Aviram M

General

Full name : Aviram Michael

First name : Michael

Mail : The Lipid Research Laboratory, Technion, Faculty of Medicine, The Rappaport Family Institute for Research in the Medical Science, Rambam Medical Center, Haifa

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Country : Israel

Email : aviram@tx.technion.ac.il

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References (115)

Title : Paraoxonase-1 overexpression prevents experimental abdominal aortic aneurysm progression - Burillo_2016_Clin.Sci.(Lond)_130_1027
Author(s) : Burillo E , Tarin C , Torres-Fonseca MM , Fernandez-Garcia CE , Martinez-Pinna R , Martinez-Lopez D , Llamas-Granda P , Camafeita E , Lopez JA , Vega de Ceniga M , Aviram M , Egido J , Blanco-Colio LM , Martin-Ventura JL
Ref : Clinical Science (Lond) , 130 :1027 , 2016
Abstract : Abdominal aortic aneurysm (AAA) is a permanent dilation of the aorta due to excessive proteolytic, oxidative and inflammatory injury of the aortic wall. We aimed to identify novel mediators involved in AAA pathophysiology, which could lead to novel therapeutic approaches. For that purpose, plasma from four AAA patients and four controls were analysed by a label-free proteomic approach. Among identified proteins, paraoxonase-1 (PON1) was decreased in plasma of AAA patients compared with controls, which was further validated in a bigger cohort of samples by ELISA. The phenylesterase enzymatic activity of PON1 was also decreased in serum of AAA patients compared with controls. To address the potential role of PON1 as a mediator of AAA, experimental AAA was induced by aortic elastase perfusion in wild-type (WT) mice and human transgenic PON1 (HuTgPON1) mice. Similar to humans, PON1 activity was also decreased in serum of elastase-induced AAA mice compared with healthy mice. Interestingly, overexpression of PON1 was accompanied by smaller aortic dilation and higher elastin and vascular smooth muscle cell (VSMC) content in the AAA of HuTgPON1 compared with WT mice. Moreover, HuTgPON1 mice display decreased oxidative stress and apoptosis, as well as macrophage infiltration and monocyte chemoattractant protein-1 (MCP1) expression, in elastase-induced AAA. In conclusion, decreased circulating PON1 activity is associated with human and experimental AAA. PON1 overexpression in mice protects against AAA progression by reducing oxidative stress, apoptosis and inflammation, suggesting that strategies aimed at increasing PON1 activity could prevent AAA.
ESTHER : Burillo_2016_Clin.Sci.(Lond)_130_1027
PubMedSearch : Burillo_2016_Clin.Sci.(Lond)_130_1027
PubMedID: 26993251

Title : Paraoxonase 1 (PON1) and pomegranate influence circadian gene expression and period length - Loizides-Mangold_2016_Chronobiol.Int_33_453
Author(s) : Loizides-Mangold U , Koren-Gluzer M , Skarupelova S , Makhlouf AM , Hayek T , Aviram M , Dibner C
Ref : Chronobiol Int , 33 :453 , 2016
Abstract : The circadian timing system regulates key aspects of mammalian physiology. Here, we analyzed the effect of the endogenous antioxidant paraoxonase 1 (PON1), a high-density lipoprotein-associated lipolactonase that hydrolyses lipid peroxides and attenuates atherogenesis, on circadian gene expression in C57BL/6J and PON1KO mice fed a normal chow diet or a high-fat diet (HFD). Expression levels of core-clock transcripts Nr1d1, Per2, Cry2 and Bmal1 were altered in skeletal muscle in PON1-deficient mice in response to HFD. These findings were supported by circadian bioluminescence reporter assessments in mouse C2C12 and human primary myotubes, synchronized in vitro, where administration of PON1 or pomegranate juice modulated circadian period length.
ESTHER : Loizides-Mangold_2016_Chronobiol.Int_33_453
PubMedSearch : Loizides-Mangold_2016_Chronobiol.Int_33_453
PubMedID: 27010443

Title : Paraoxsonase2 (PON2) and oxidative stress involvement in pomegranate juice protection against cigarette smoke-induced macrophage cholesterol accumulation - Rom_2016_Chem.Biol.Interact_259_394
Author(s) : Rom O , Aviram M
Ref : Chemico-Biological Interactions , 259 :394 , 2016
Abstract : Exposure to cigarette smoke (CS) promotes various stages of atherosclerosis development. Macrophages are the predominant cells in early atherogenesis, and the polyphenolic-rich pomegranate juice (PJ) is known for its protective role against macrophage atherogenicity. The aim of the current study was to examine the atherogenic effects of CS on macrophages, and to evaluate the protective effects of PJ against CS-induced macrophage atherogenicity. Murine J774A.1 macrophages were treated with CS-exposed medium in the absence or presence of PJ. Parameters of lipid peroxidation in CS-exposed medium were measured by the lipid peroxides and thiobarbituric acid reactive substances (TBARS) assays. Atherogenicity of macrophages incubated with increasing concentrations of CS-exposed medium was assessed by cytotoxicity, oxidative stress determined by generation of reactive oxygen species (ROS) using DCFH-DA, activity of the cellular anti-oxidant paraoxonase2 (PON2), macrophage accumulation of cholesterol and triglycerides, as well as through high density lipoprotein (HDL)-mediated cholesterol efflux from the cells. CS exposure resulted in significant and dose-dependent increases in lipid peroxides and TBARS medium levels (up to 3 and 8-fold, respectively). Incubation of macrophages with CS-exposed medium resulted in dose-dependent increases in macrophage damage/injury (up to 6-fold), intracellular ROS levels (up to 31%), PON2 activity (up to 2-fold), and macrophage cholesterol content (up to 24%). The latter might be explained by reduced HDL-mediated cholesterol efflux from CS-exposed macrophages (by 21%). PJ protected macrophages from CS-induced increases in intracellular ROS levels and cholesterol accumulation, as well as the attenuated efflux of cholesterol. These data indicate that CS stimulates macrophage oxidation and activates PON2 as a possible compensatory response to the oxidative burden. CS impairs HDL-mediated cholesterol efflux from macrophages leading to cellular accumulation of cholesterol. The atherogenic and oxidative effects of CS are attenuated by PJ, a polyphenolic-rich anti-oxidant.
ESTHER : Rom_2016_Chem.Biol.Interact_259_394
PubMedSearch : Rom_2016_Chem.Biol.Interact_259_394
PubMedID: 27163848

Title : Paraoxonase 1 (PON1) reduces macrophage inflammatory responses - Aharoni_2013_Atherosclerosis_228_353
Author(s) : Aharoni S , Aviram M , Fuhrman B
Ref : Atherosclerosis , 228 :353 , 2013
Abstract : OBJECTIVES: Paraoxonase 1 (PON1) was suggested to play an anti-inflammatory role. In the present study we questioned whether PON1 has a direct impact on macrophage inflammatory responses, and the possible functional implications of such effects. METHODS AND
RESULTS: Ex-vivo studies were performed with bone marrow-derived macrophages (BMDM) harvested from C57BL/6 and human-PON1 transgenic (PON1-Tg) mice, and for the in vitro studies the J774.A1 macrophage-like cell line was used. Pro-inflammatory (M1) activation was induced by LPS and INFgamma. The spontaneous and M1-induced TNFalpha and IL-6 secretion were significantly reduced in BMDM derived from PON1-Tg vs. C57BL/6 mice. In vitro, PON1 dose-dependently attenuated both the spontaneous and M1-induced TNFalpha and IL-6 secretion, and contributed to the anti-inflammatory activity of HDL. Functionally, PON1 attenuated M1-induced production of reactive oxygen species (ROS), phagocytosis, and necrotic macrophage death. PON1 anti-inflammatory activity was mediated, at least in part, via binding to SR-BI, but was independent of the enzyme catalytic activity or of cholesterol efflux stimulation, and did not involve binding to ABCA1.
CONCLUSIONS: The present study demonstrates, for the first time, that PON1 directly suppresses macrophage pro-inflammatory responses. These findings suggest that PON1 decreases sustained pro-inflammatory reactions, which subsequently can attenuate plaque progression.
ESTHER : Aharoni_2013_Atherosclerosis_228_353
PubMedSearch : Aharoni_2013_Atherosclerosis_228_353
PubMedID: 23582715

Title : Paraoxonase1 (PON1) reduces insulin resistance in mice fed a high-fat diet, and promotes GLUT4 overexpression in myocytes, via the IRS-1\/Akt pathway - Koren-Gluzer_2013_Atherosclerosis_229_71
Author(s) : Koren-Gluzer M , Aviram M , Hayek T
Ref : Atherosclerosis , 229 :71 , 2013
Abstract : OBJECTIVE: To analyze Paraoxonase1 (PON1) impact on GLUT4 expression, glucose metabolism, and the insulin signaling pathway in skeletal muscle cells. METHODS AND
RESULTS: We analyzed the effect of PON1 in high-fat-diet-induced insulin resistance in C57BL/6J and in PON1KO mice. Mice were fed normal diet (ND) or high Fat Diet (HFD) for 8 weeks. PON1 deficiency caused enhanced insulin resistance in both ND and HFD mice. PON1 deficiency was associated with increased oxidative stress (OS), increased p38MAPK activity and attenuated insulin-mediated tyrosine phosphorylation of muscle insulin receptor substrate-1 (IRS-1), with a corresponding increase in serine phosphorylation. These effects resulted in decreased glucose uptake in whole-body level, as reflected by glucose tolerance test (GTT), by insulin tolerance test (ITT) and by cellular glycogen accumulation in the liver and in the muscles. PON1 addition to cultured C2 muscle cells enhanced GLUT4 mRNA expression, in a time and concentration dependent manner, increased GLUT4 protein and cellular glycogen accumulation. These effects were mediated via inhibition of p38MAPK activity, resulting in reduced IRS-1 serine phosphorylation and in enhanced IRS-1 tyrosine phosphorylation. The ability of PON1 to increase myocytes GLUT4 expression was partially inhibited upon blocking PON1 SH group, and completely abolished upon PON1 mutation in HIS115 of its catalytic site. CONCLUSION: PON1 plays a beneficial role in glucose regulation and metabolism and may serve as an important tool in diabetes control.
ESTHER : Koren-Gluzer_2013_Atherosclerosis_229_71
PubMedSearch : Koren-Gluzer_2013_Atherosclerosis_229_71
PubMedID: 23639858

Title : Pomegranate for your cardiovascular health - Aviram_2013_Rambam.Maimonides.Med.J_4_e0013
Author(s) : Aviram M , Rosenblat M
Ref : Rambam Maimonides Med J , 4 :e0013 , 2013
Abstract : Pomegranate is a source of some very potent antioxidants (tannins, anthocyanins) which are considered to be also potent anti-atherogenic agents. The combination of the above unique various types of pomegranate polyphenols provides a much wider spectrum of action against several types of free radicals. Indeed, pomegranate is superior in comparison to other antioxidants in protecting low-density lipoprotein (LDL, "the bad cholesterol") and high-density lipoprotein (HDL, "the good cholesterol") from oxidation, and as a result it attenuates atherosclerosis development and its consequent cardiovascular events. Pomegranate antioxidants are not free, but are attached to the pomegranate sugars, and hence were shown to be beneficial even in diabetic patients. Furthermore, pomegranate antioxidants are unique in their ability to increase the activity of the HDL-associated paraoxonase 1 (PON1), which breaks down harmful oxidized lipids in lipoproteins, in macrophages, and in atherosclerotic plaques. Finally, unique pomegranate antioxidants beneficially decrease blood pressure. All the above beneficial characteristics make the pomegranate a uniquely healthy fruit.
ESTHER : Aviram_2013_Rambam.Maimonides.Med.J_4_e0013
PubMedSearch : Aviram_2013_Rambam.Maimonides.Med.J_4_e0013
PubMedID: 23908863

Title : Monocyte-macrophage membrane possesses free radicals scavenging activity: stimulation by polyphenols or by paraoxonase 1 (PON1) - Rosenblat_2013_Free.Radic.Res_47_257
Author(s) : Rosenblat M , Elias A , Volkova N , Aviram M
Ref : Free Radical Research , 47 :257 , 2013
Abstract : In the current study, we analysed free radicals scavenging activity of monocytes-macrophages in the absence or presence of antioxidants such as polyphenols or paraoxonase 1 (PON1). THP-1 human monocytic cell line, murine J774A.1 macrophages, as well as human primary monocytes have the capability to scavenge free radicals, as measured by the 1-diphenyl-2-picryl-hydrazyl (DPPH) assay. This effect (which could be attributed to the cell's membrane) was cell number and incubation time dependent. Upon incubation of J774A.1 macrophages with acetylated LDL (Ac-LDL), with VLDL, or with the radical generator, AAPH, the cells' lipid peroxides content, and paraoxonase 2 (PON2) activity were significantly increased. While non-treated cells decreased DPPH absorbance by 65%, the Ac-LDL-, VLDL- or AAPH-treated cells, decreased it by only 33%, 30%, or 45%, respectively. We next analysed the effect of J774A.1 macrophage enrichment with antioxidants, such as polyphenols or PON1 on the cells' free radicals scavenging activity. Non-treated cells decreased DPPH absorbance by 50%, whereas vitamin E-, punicalagin- or PJ-treated cells significantly further decreased it, by 75%. Similarly, in PON1-treated cells DPPH absorbance was further decreased by 63%, in association with 23% increment in PON1 catalytic activity. In cells under oxidative stress [treated with AAPH-, or with oxidized LDL], PON1 activity was decreased by 31% or 40%, as compared to the activity observed in PON1 incubated with non-treated cells. We conclude that monocytes-macrophages possess free radicals scavenging activity, which is decreased under atherogenic conditions, and increased upon cell enrichment with potent antioxidants such as nutritional polyphenols, or PON1.
ESTHER : Rosenblat_2013_Free.Radic.Res_47_257
PubMedSearch : Rosenblat_2013_Free.Radic.Res_47_257
PubMedID: 23316782

Title : Paraoxonase 1 activities, regulation, and interactions with atherosclerotic lesion - Aviram_2013_Curr.Opin.Lipidol_24_339
Author(s) : Aviram M , Vaya J
Ref : Curr Opin Lipidol , 24 :339 , 2013
Abstract : PURPOSE OF REVIEW: Improving serum levels of HDL and its subfractions, as well as, oxidative/inflammatory properties has become a fundamental aim in today's atherosclerosis research. Efforts to reach this goal are paralleled by achievements in drug development toward decreasing serum LDL levels and oxidative status. RECENT FINDINGS: Paraoxonase1 (PON1) is an HDL-associated enzyme that is deemed responsible for many of the HDL's antiatherogenic and cardioprotective characteristics. PON1 is highly sensitive to variations in its milieu, and endogenous compounds (fatty acids, phospholipids), nutritional ingredients (flavonoids and other antioxidants), and environmental elements (reactive nitrogen and oxygen species, metals, surfactants), significantly affect the enzyme's activities. PON1 was shown to be responsible for some of the HDL antiatherogenic characteristics such as HDL-mediated cholesterol efflux from macrophages, and the inhibition of LDL oxidation. SUMMARY: The present review summarizes the recent literature related to various elements in PON1's milieu that regulate its activities, with an emphasis on its interrelation with components of the human carotid atherosclerotic lesion (plaque) which are in constant contact with circulating HDL-associated PON1.
ESTHER : Aviram_2013_Curr.Opin.Lipidol_24_339
PubMedSearch : Aviram_2013_Curr.Opin.Lipidol_24_339
PubMedID: 23508039

Title : Pomegranate phytosterol (beta-sitosterol) and polyphenolic antioxidant (punicalagin) addition to statin, significantly protected against macrophage foam cells formation - Rosenblat_2013_Atherosclerosis_226_110
Author(s) : Rosenblat M , Volkova N , Aviram M
Ref : Atherosclerosis , 226 :110 , 2013
Abstract : OBJECTIVE: To assess the anti-atherogenic effects on macrophage cholesterol biosynthesis rate, and on cellular oxidative stress by the combination of simvastatin with a potent polyphenolic antioxidant (punicalagin), or with a phytosterol (beta-sitosterol), or with pomegranate juice (POM, that contains both of them). METHODS AND
RESULTS: Simvastatin (15 mug/ml) decreased J774A.1 macrophage cholesterol biosynthesis rate by 42% as compared to control cells. The addition to the statin of either punicalagin (15 or 30 muM), or beta-sitosterol (50 or 100 muM), increased the inhibitory effect of the statin up to 62% or 57%, respectively. Similarly, the combination of POM and simvastatin, resulted in an inhibitory effect up to 59%. While simvastatin inhibited the rate limiting enzyme HMGCoA-reductase, punicalagin, beta-sitosterol or POM inhibited macrophage cholesterol biosynthesis downstream to mevalonate. Simvastatin (15 mug/ml) also modestly decreased macrophage reactive oxygen species (ROS) formation by 11%. In the presence of punicalagin (15 or 30 muM) however, a remarkable further inhibition was noted (by 61% or 79%, respectively). Although beta-sitosterol alone showed some pro-oxidant activity, the combination of simvastatin, beta-sitosterol and punicalagin, clearly demonstrated a remarkable 73% reduction in ROS production. Similarly, simvastatin + POM decreased the extent of ROS formation by up to 63%. These improved antioxidant effects of the combinations could be related to various anti-oxidative properties of the different compounds, including free radicals scavenging capacity, upregulation of paraoxonase 2, and stimulation of reduced glutathione. CONCLUSION: The combination of simvastatin with potent antioxidant and phytosterol (such as present in pomegranate) could lead to attenuation of macrophage foam cell formation and atherogenesis.
ESTHER : Rosenblat_2013_Atherosclerosis_226_110
PubMedSearch : Rosenblat_2013_Atherosclerosis_226_110
PubMedID: 23141585

Title : Atherosclerosis: cell biology and lipoproteins - paraoxonases protect against atherosclerosis and diabetes development -
Author(s) : Aviram M
Ref : Curr Opin Lipidol , 23 :169 , 2012
PubMedID: 22418576

Title : Paraoxonase1 deficiency in mice is associated with hypotension and increased levels of 5,6-epoxyeicosatrienoic acid - Gamliel-Lazarovich_2012_Atherosclerosis_222_92
Author(s) : Gamliel-Lazarovich A , Abassi Z , Khatib S , Tavori H , Vaya J , Aviram M , Keidar S
Ref : Atherosclerosis , 222 :92 , 2012
Abstract : AIM: Serum paraoxonase 1 (PON1) is an HDL-associated lipolactonase and its association with hypertension is controversial. We studied the possible role of PON1 in blood pressure (BP) regulation, by using PON1 knockout (PON1KO) mice. METHODS AND
RESULTS: Both, systolic and diastolic BPs were lower in PON1KO compared to WT mice. Hypotension detected in PON1KO is probably neither related to nitric oxide/guanylate cyclase-mediated vasodilation nor to angiotensin II or aldosterone-mediated vasoconstriction. Surprisingly, when challenged by high-salt diet, BP was further reduced in PON1KO mice. The later, pointed to a possible involvement of transient receptor potential vanilloid 4 (TRPV4), and indeed, administration of ruthenium red, a TRPV4 blocker, resulted in a sharp rise in BP. The protein levels of TRPV4 in kidneys of PON1KO were not higher than in WT. However, the renal level of 5,6-epoxyeicosatrienoic acid (5,6-EET), a TRPV4 specific agonist, was significantly higher in PON1KO compared with WT mice. 5,6-EET levels were further elevated under high-salt diet or administration of arachidonic acid. Injection of inhibitor of CYP450 epoxygenase resulted in increased BP in PON1KO mice. Injection of recombinant human PON1 resulted in elevation of BP and a concomitant reduction in renal content of 5,6-EET. PON1, in vitro, metabolized 5,6-EET, but not other EETs, to its corresponding diol. Vasodilation, blocked by excess of dietary K(+) but not reversed by depletion of cellular Ca(2+) stores, point to endothelial-derived hyperpolarization-like response. CONCLUSION: The present study shows causal, direct relationship between PON1 and blood pressure which is mediated, at least in part, by the regulation of 5,6-EET.
ESTHER : Gamliel-Lazarovich_2012_Atherosclerosis_222_92
PubMedSearch : Gamliel-Lazarovich_2012_Atherosclerosis_222_92
PubMedID: 22365750

Title : Triglyceride accumulation in macrophages upregulates paraoxonase 2 (PON2) expression via ROS-mediated JNK\/c-Jun signaling pathway activation - Rosenblat_2012_Biofactors_38_458
Author(s) : Rosenblat M , Volkova N , Paland N , Aviram M
Ref : Biofactors , 38 :458 , 2012
Abstract : The aim of this study was to analyze the effect and mechanism of action of macrophage triglyceride accumulation on cellular PON2 expression. Incubation of J774A.1 (murine macrophages) with VLDL (0-75 mug protein/mL) significantly and dose-dependently increased cellular triglyceride mass, and reactive oxygen species (ROS) formation, by up to 3.3- or 1.8-fold, respectively. PON2 expression (mRNA, protein, activity) in cells treated with VLDL (50 mug protein/mL) was higher by 2- to 3-fold, as compared with control cells. Similar effects were noted upon using THP-1 (human macrophages). Incubation of macrophages with synthetic triglyceride or triglyceride fraction from carotid lesion resulted in similar effects, as shown for VLDL. Upon using specific inhibitors of MEK1/2 (UO126, 10 muM), p38 (SB203580, 10 muM), or JNK (SP600125, 20 muM), we demonstrated that MEK, as well as JNK, but not p38, are involved in VLDL-induced macrophage PON2 upregulation. VLDL activated JNK (but not ERK), which resulted in c-Jun phosphorylation. This signaling pathway is probably activated by ROS, since the antioxidant reduced glutathione (GSH), significantly decreased VLDL-induced macrophage ROS formation, c-Jun phosphorylation and PON2 overexpression. We conclude that macrophage triglyceride accumulation upregulates PON2 expression via MEK/ JNK/c-Jun pathway, and these effects could be related, at least in part, to cellular triglycerides-induced ROS formation. (c)
ESTHER : Rosenblat_2012_Biofactors_38_458
PubMedSearch : Rosenblat_2012_Biofactors_38_458
PubMedID: 23047827

Title : VLDL triglycerides inhibit HDL-associated paraoxonase 1 (PON1) activity: in vitro and in vivo studies - Rosenblat_2012_Biofactors_38_292
Author(s) : Rosenblat M , Ward S , Volkova N , Hayek T , Aviram M
Ref : Biofactors , 38 :292 , 2012
Abstract : We analyzed, for the first time, both in vitro and in vivo, the effect of very low density lipoprotein (VLDL), or of pure triglycerides, on high-density lipoprotein (HDL)-associated paraoxonase1 (PON1) catalytic activities. Incubation of serum or HDL from healthy subjects with VLDL (0-330 mug protein/mL) significantly decreased serum PON1 lactonase or arylesterase activities by up to 11% or 24%, and HDL-associated PON1 lactonase or arylesterase activities by up to 32% or 46%, respectively, in a VLDL dose-dependent manner. VLDL (0-660 mug protein/mL) also inhibited recombinant PON1 (rePON1) lactonase or arylesterase activities by up to 20% or 42%, respectively. Similar inhibitory effect was noted upon rePON1 incubation with pure triglyceride emulsion. Bezafibrate therapy to three hypertriglyceridemic patients (400 mg/day, for one month) significantly decreased serum triglyceride concentration by 67%, and increased serum HDL cholesterol levels by 48%. PON1 arylesterase or paraoxonase activities in the patients' HDL fractions after drug therapy were significantly increased by 86-88%, as compared to PON1 activities before treatment. Similarly, HDL-PON1 protein levels significantly increased after bezafibrate therapy. Finally, bezafibrate therapy improved HDL biological activity, as HDL obtained after drug therapy showed increased ability to induce cholesterol efflux from J774A.1 macrophages, by 19%, as compared to HDL derived before therapy. We thus conclude that VLDL triglycerides inhibit PON1 catalytic activities, and bezafibrate therapy significantly improved HDL-PON1 catalytic and biological activities.
ESTHER : Rosenblat_2012_Biofactors_38_292
PubMedSearch : Rosenblat_2012_Biofactors_38_292
PubMedID: 22674772

Title : Paraoxonase activity and expression is modulated by therapeutics in experimental rat nonalcoholic Fatty liver disease - Hussein_2012_Int.J.Hepatol_2012_265305
Author(s) : Hussein O , Zidan J , Abu Jabal K , Shams I , Szvalb S , Grozovski M , Bersudsky I , Karry R , Aviram M
Ref : Int Journal of Hepatology , 2012 :265305 , 2012
Abstract : Objective. The objective of the present study is to investigate the effect of rosiglitazone, metformin, ezetimibe, and valsartan (alone or in combinations) on paraoxonase (PON) activity and PON-mRNA expression in nonalcoholic fatty liver disease (NAFLD). Methods. 54 Male Sprague-Dawley rats were divided to 9 groups: chow diet group (15 weeks); methionine-choline-deficient diet (MCDD) group (15 weeks); MCDD-treated groups for the last 6 weeks with either metformin (M), rosiglitazone (R), metformin plus rosiglitazone (M+R), ezetimibe (E), valsartan (V), or a combination of R+M+V or of R+M+V+E for a total period of 15 weeks. Results. PON activities in serum and liver were decreased in MCDD rats. PON activity in serum increased significantly in all treatment groups. PON activity in liver was also increased significantly, except only in groups R, E, V, R+M+V, and R+M+V+E. Liver PON3 mRNA expression increased significantly in groups R+M, E, V, R+M+V, and R+M+V+E whereas liver PON2 mRNA expression increased significantly in MCDD, R+M, E, V, R+M+V, and R+M+V+E. Conclusions. PON activities in serum and liver were decreased in NAFLD. Treatment with insulin sensitizers, ezetimibe, and valsartan increased PON activity and reduced oxidative stress both in serum and liver.
ESTHER : Hussein_2012_Int.J.Hepatol_2012_265305
PubMedSearch : Hussein_2012_Int.J.Hepatol_2012_265305
PubMedID: 22536512

Title : Increased Levels of Human Carotid Lesion Linoleic Acid Hydroperoxide in Symptomatic and Asymptomatic Patients Is Inversely Correlated with Serum HDL and Paraoxonase 1 Activity - Cohen_2012_J.Lipids_2012_762560
Author(s) : Cohen E , Aviram M , Khatib S , Rabin A , Mannheim D , Karmeli R , Vaya J
Ref : J Lipids , 2012 :762560 , 2012
Abstract : Human carotid plaque components interact directly with circulating blood elements and thus they might affect each other. We determined plaque paraoxonase1 (PON1) hydrolytic-catalytic activity and compared plaque and blood levels of lipids, HDL, PON1, and HbA1c, as well as plaque-oxidized lipids in symptomatic and asymptomatic patients. Human carotid plaques were obtained from symptomatic and asymptomatic patients undergoing routine endarterectomy, and the lesions were ground and extracted for PON activity and lipid content determinations. Plaque PONs preserved paraoxonase, arylesterase, and lactonase activities. The PON1-specific inhibitor 2-hydroxyquinoline almost completely inhibited paraoxonase and lactonase activities, while only moderately inhibiting arylesterase activity. Oxysterol and triglyceride levels in plaques from symptomatic and asymptomatic patients did not differ significantly, but plaques from symptomatic patients had significantly higher (135%) linoleic acid hydroperoxide (LA-13OOH) levels. Their serum PON1 activity, cholesterol and triglyceride levels did not differ significantly, but symptomatic patients had significantly lower (28%) serum HDL levels and higher (18%) HbA1c levels. Thus LA-13OOH, a major atherogenic plaque element, showed significant negative correlations with serum PON1 activity and HDL levels, and a positive correlation with the prodiabetic atherogenic HbA1c. Plaque PON1 retains its activity and may decrease plaque atherogenicity by reducing specific oxidized lipids (e.g., LA-13OOH). The inverse correlation between plaque LA-13OOH level and serum HDL level and PON1 activity suggests a role for serum HDL and PON1 in LA-13OOH accumulation.
ESTHER : Cohen_2012_J.Lipids_2012_762560
PubMedSearch : Cohen_2012_J.Lipids_2012_762560
PubMedID: 22690338

Title : Urokinase-type plasminogen activator downregulates paraoxonase 1 expression in hepatocytes by stimulating peroxisome proliferator-activated receptor-gamma nuclear export - Khateeb_2012_Arterioscler.Thromb.Vasc.Biol_32_449
Author(s) : Khateeb J , Kiyan Y , Aviram M , Tkachuk S , Dumler I , Fuhrman B
Ref : Arterioscler Thromb Vasc Biol , 32 :449 , 2012
Abstract : OBJECTIVE: The atherosclerotic lesion is characterized by lipid peroxide accumulation. Paraoxonase 1 (PON1) reduces atherosclerotic lesion oxidative stress, whereas urokinase-type plasminogen activator (uPA) increases oxidative stress in atherosclerotic lesions and contributes to the progression and complications of atherosclerosis. We hypothesized that uPA may promote oxidative stress in the arterial wall via modulation of PON1 activity. Because the liver is the main site for PON1 production, in the present study, we tested whether uPA influences PON1 expression in hepatocytes. METHODS AND
RESULTS: HuH7 hepatocytes were incubated in culture with increasing concentrations of uPA. uPA decreased PON1 gene expression and activity in a dose-dependent manner and accordingly suppressed PON1 secretion from hepatocytes. This effect required uPA/uPA receptor interaction. uPA downregulated PON1 gene expression via inactivation of peroxisome proliferator-activated receptor-gamma (PPARgamma) activity, and this effect was dependent on uPA-mediated mitogen-activated protein kinase kinase activation. Mechanistic studies showed that uPA enhanced mitogen-activated protein kinase kinase-PPARgamma interaction, resulting in PPARgamma nuclear export to the cytosol.
CONCLUSIONS: This study provides the first evidence that uPA interferes with PPARgamma transcriptional activity in hepatocytes, resulting in downregulation of PON1 expression and its secretion to the medium. This may explain, at least in part, the prooxidative effect of uPA in the vascular wall.
ESTHER : Khateeb_2012_Arterioscler.Thromb.Vasc.Biol_32_449
PubMedSearch : Khateeb_2012_Arterioscler.Thromb.Vasc.Biol_32_449
PubMedID: 22155455

Title : Human carotid lesion linoleic acid hydroperoxide inhibits paraoxonase 1 (PON1) activity via reaction with PON1 free sulfhydryl cysteine 284 - Tavori_2011_Free.Radic.Biol.Med_50_148
Author(s) : Tavori H , Aviram M , Khatib S , Musa R , Mannheim D , Karmeli R , Vaya J
Ref : Free Radic Biol Med , 50 :148 , 2011
Abstract : Paraoxonase 1 (PON1) is an HDL-associated lactonase with antiatherogenic properties. These include dampening the oxidation properties of human carotid lesion lipid extract (LLE), which in turn inactivates the enzyme. The aims of this study were to identify the PON1 inhibitor in LLE and explore the mechanism of inhibition. LLE inhibited both recombinant PON1 and HDL-PON1 lactonase activity in a dose- and time-dependent manner. Addition of antioxidants or electrophiles to LLE did not prevent PON1 inhibition. LLE was unable to inhibit a PON1 mutant lacking Cys284, whereas it did inhibit all other PON1 mutants tested. The inhibitor in the LLE was identified as linoleic acid hydroperoxide (LA-OOH) and inhibition was specific to this hydroperoxide. During its inhibition, PON1 acted like a peroxidase enzyme, reducing LA-OOH to LA-hydroxide via its Cys284. A similar reaction occurred with external thiols, such as DDT or cysteine, which also prevented PON1 inhibition and restored enzyme activity after inhibition. Thus, the antiatherogenic properties of HDL could be, at least in part, related to the sulfhydryl-reducing characteristics of its associated PON1, which are further protected and recycled by the sulfhydryl amino acid cysteine.
ESTHER : Tavori_2011_Free.Radic.Biol.Med_50_148
PubMedSearch : Tavori_2011_Free.Radic.Biol.Med_50_148
PubMedID: 21044882

Title : Paraoxonase 1 protects macrophages from atherogenicity of a specific triglyceride isolated from human carotid lesion - Tavori_2011_Free.Radic.Biol.Med_51_234
Author(s) : Tavori H , Aviram M , Khatib S , Musa R , Mannheim D , Karmeli R , Vaya J
Ref : Free Radic Biol Med , 51 :234 , 2011
Abstract : Human atherosclerotic lesions contain oxidized lipids that facilitate further oxidation of macrophages, LDLs, and oxidative stress (OS)-sensitive markers and inhibit the antiatherogenic enzyme paraoxonase 1 (PON1). Our aim was to isolate and identify the oxidizing agent in a human atherosclerotic lesion lipid extract (LLE) and to explore the mechanisms of oxidation and of PON1's effect on the oxidizing agent. Of the five main fractions separated from the LLE, only fraction 2 (F2) promoted macrophage reactive oxygen species (ROS) production via a mechanism requiring mitochondrial involvement, whereas the NADPH oxidase system was not involved. Incubation of F2 with PON1 abridged the former's peroxide value and reduced its capacity to oxidize OS markers. The active agent was a triglyceride composed of palmitic, oleic, and linoleic acids, with 0.3% of its linoleic moiety in oxidized form. Incubation of either F2 or an identical synthetic triglyceride with PON1 reduced their ability to oxidize macrophages, without affecting cellular accumulation of triglycerides. We conclude that macrophage ROS production by LLE occurs in the presence of a specific triglyceride and requires mitochondrial involvement. Lipid peroxide in the triglyceride can also facilitate lipid autoxidation. Both atherogenic pathways are suppressed by PON1, which acts as an antiatherogenic element.
ESTHER : Tavori_2011_Free.Radic.Biol.Med_51_234
PubMedSearch : Tavori_2011_Free.Radic.Biol.Med_51_234
PubMedID: 21530644

Title : Atherosclerosis: cell biology and lipoproteins--inflammation and oxidative stress in atherogenesis: protective role for paraoxonases -
Author(s) : Aviram M
Ref : Curr Opin Lipidol , 22 :243 , 2011
PubMedID: 21562389

Title : The antioxidant HDL-associated paraoxonase-1 (PON1) attenuates diabetes development and stimulates beta-cell insulin release - Koren-Gluzer_2011_Atherosclerosis_219_510
Author(s) : Koren-Gluzer M , Aviram M , Meilin E , Hayek T
Ref : Atherosclerosis , 219 :510 , 2011
Abstract : OBJECTIVE: To analyze the direct effects of paraoxonase-1 (PON1) on diabetes development and on beta-cell insulin release. METHODS AND
RESULTS: Injection of rePON1 to mice, prior to STZ-induced diabetes, resulted in reduced incidence of diabetes, as well as, in higher serum insulin levels. Incubation of beta-cells with PON1 also dose-dependently increased insulin secretion and its cellular content. PON1 increased cell survival under high glucose levels, but not under high STZ concentrations. The addition of the PON1 carrier in the circulation - HDL, to betaTC3 cell line, had an additive effect on PON1-induced insulin secretion. PON1 administration to mice or incubation with beta-cells was associated with a substantial decreased oxidative stress. Just like PON1, the dietary anti-oxidants, pomegranate juice, punicalagin (major polyphenol in pomegranate) or vitamin E, also increased insulin release from betaTC3, but unlike PON1, failed to increase insulin cellular content, suggesting a possible role for PON1 in insulin biosynthesis, separately from PON1 antioxidative effect. Both, PON1 catalytic activity and PON1 association to HDL, were not required for PON1 stimulation of insulin release from beta-cells. However, the PON1 free sulfhydryl group was shown to be essential for insulin release by PON1, as blocking the PON1 SH group, abolished PON1 stimulatory effect on insulin secretion. CONCLUSION: PON1 is a potent anti-diabetic enzyme that exerts this protection against diabetes through its antioxidative, as well as via its insulin stimulation properties on beta-cells.
ESTHER : Koren-Gluzer_2011_Atherosclerosis_219_510
PubMedSearch : Koren-Gluzer_2011_Atherosclerosis_219_510
PubMedID: 21862013

Title : Insulin increases macrophage triglyceride accumulation under diabetic conditions through the down regulation of hormone sensitive lipase and adipose triglyceride lipase - Meilin_2011_Biofactors_37_95
Author(s) : Meilin E , Aviram M , Hayek T
Ref : Biofactors , 37 :95 , 2011
Abstract : Diabetes mellitus (DM) is a major risk factor for the development of atherosclerosis, and high-serum levels of insulin are strongly associated with type 2 DM. Atherosclerosis is characterized by lipid-laden macrophage foam cell formations, which contain substantial amount of cholesterol and triglycerides (TG). This study analyzed for the first time, the effects of insulin on TG metabolism in macrophages under normal and diabetic conditions. Mouse peritoneal macrophages from C57BL6 mice were cultured under normal (5 mM) or high (diabetic condition, 25 mM) glucose concentration, with or without insulin, followed by the assessment of TGs metabolism in these cells. Under diabetic condition, insulin increased TG accumulation in macrophages by 100%, decreased cellular TG degradation by 21%, and increased C-reactive protein levels in macrophages by 83%. Insulin decreased hormone-sensitive lipase mRNA and protein expression by 28 and 60%, respectively, and adipose TG lipase (ATGL) protein expression by 36%, with no significant reduction in ATGL mRNA levels. The inhibition of insulin-mediated phosphorylation, and the addition of cyclic adenosine 3'5'-monoposphate, abolished the insulin-mediated inhibition of TGs degradation in cells. Insulin increases macrophage TGs accumulation only under diabetic conditions, suggesting that impaired glycemic control in diabetic patients treated with insulin may contribute to foam cell formations and enhanced inflammation in macrophages.
ESTHER : Meilin_2011_Biofactors_37_95
PubMedSearch : Meilin_2011_Biofactors_37_95
PubMedID: 21344529

Title : Pomegranate juice protects macrophages from triglyceride accumulation: inhibitory effect on DGAT1 activity and on triglyceride biosynthesis - Rosenblat_2011_Ann.Nutr.Metab_58_1
Author(s) : Rosenblat M , Aviram M
Ref : Ann Nutr Metab , 58 :1 , 2011
Abstract : BACKGROUND/AIMS: To analyze the effects of pomegranate juice (PJ) and punicalagin on macrophage triglyceride metabolism.
METHODS: Triglyceride metabolism was analyzed in PJ- or punicalagin-treated J774A.1 macrophages or in mouse peritoneal macrophages (MPM) harvested from C57BL/6 mice or from paraoxonase 2 (PON2)-deficient mice.
RESULTS: PJ (0-50 muM) significantly and dose-dependently decreased the triglyceride content and triglyceride biosynthesis rate in J774A.1 macrophages or in C57BL/6 MPM by about 30%. Similarly, punicalagin, the major PJ polyphenol, inhibited the MPM triglyceride biosynthesis rate by 40%. The triglyceride hydrolytic rate, however, was not significantly affected by PJ or punicalagin. The activity of diacylglycerol acyltransferase 1 (DGAT1; the rate-limiting enzyme in triglyceride biosynthesis) was significantly inhibited, by 54%, in C57BL/6 MPM that were treated with 50 muM PJ or punicalagin, with no significant effect on DGAT1 mRNA or protein expression. Both PJ and punicalagin increased (1.7-fold) MPM PON2 mRNA expression, and PON2 was previously shown to inhibit DGAT1 activity. However, the addition of PJ or punicalagin (50 muM) to microsomes from PON2-deficient MPM still resulted in a significant reduction (50-58%) in DGAT1 activity.
CONCLUSIONS: We conclude that the inhibitory effect of PJ on triglyceride biosynthesis could be attributed to a direct effect of PJ on DGAT1 activity.
ESTHER : Rosenblat_2011_Ann.Nutr.Metab_58_1
PubMedSearch : Rosenblat_2011_Ann.Nutr.Metab_58_1
PubMedID: 21212659

Title : Paraoxonase-1 and clopidogrel efficacy -
Author(s) : Camps J , Joven J , Mackness B , Mackness MI , Tawfik DS , Draganov DI , Costa LG , Paragh G , Seres I , Horke S , James RW , Hernandez AF , Reddy ST , Shih DM , Navab M , Rochu D , Aviram M
Ref : Nat Med , 17 :1041 , 2011
PubMedID: 21900915

Title : Consumption of pomegranate decreases serum oxidative stress and reduces disease activity in patients with active rheumatoid arthritis: a pilot study - Balbir-Gurman_2011_Isr.Med.Assoc.J_13_474
Author(s) : Balbir-Gurman A , Fuhrman B , Braun-Moscovici Y , Markovits D , Aviram M
Ref : Isr Med Assoc J , 13 :474 , 2011
Abstract : BACKGROUND: Pomegranate extract (POMx) consumption has been shown to reduce the incidence and severity of collagen-induced arthritis in mice. OBJECTIVES: To investigate whether pomegranate consumption affects disease activity in patients with rheumatoid arthritis (RA), in relation to their serum oxidative status.
METHODS: In this pilot 12 week open-labeled study eight patients with active RA consumed POMx (10 ml/day) for 12 weeks. Patients' joint status and serum oxidative status (lipid peroxidation, total thiols group, paraoxonase 1 activity) were evaluated at baseline and at week 12.
RESULTS: Six patients completed the study. POMx consumption significantly (P < 0.02) reduced the composite Disease Activity Index (DAS28) by 17%, which could be related mostly to a significant (P < 0.005) reduction in the tender joint count (by 62%). These results were associated with a significant (P < 0.02) reduction in serum oxidative status and a moderate but significant (P < 0.02) increase in serum high density lipoprotein-associated paraoxonase 1 (PON1) activity. The addition of POMx to serum from RA patients reduced free radical-induced lipid peroxidation by up to 25%.
CONCLUSIONS: The pomegranate consumption reduced DAS28 in RA patients, and this effect could be related to the antioxidative property of pomegranates. Dietary supplementation with pomegranates may be a useful complementary strategy to attenuate clinical symptoms in RA patients.
ESTHER : Balbir-Gurman_2011_Isr.Med.Assoc.J_13_474
PubMedSearch : Balbir-Gurman_2011_Isr.Med.Assoc.J_13_474
PubMedID: 21910371

Title : Injection of paraoxonase 1 (PON1) to mice stimulates their HDL and macrophage antiatherogenicity - Rosenblat_2011_Biofactors_37_462
Author(s) : Rosenblat M , Volkova N , Aviram M
Ref : Biofactors , 37 :462 , 2011
Abstract : We analyzed, for the first time, the effects of recombinant PON1 (rePON1) intraperitoneal injection to C(5)(7)BL/6 mice on their HDL and macrophage antiatherogenic properties. Thioglycolate-treated mice were injected with either saline (Control), or rePON1 (50 mug/mouse), and 20 H post injection, their blood samples and peritoneal macrophages (MPM) were collected. A significant increase in serum and HDL-PON1 arylesterase and lactonase activities was noted. Similarly, a significant increment, by 3.8 and 2.8 fold, in MPM-PON1 arylesterase and lactonase activities, respectively, as compared to the activities in control MPM was observed. The HDL from rePON1-injected mice was resistant to oxidation by copper ions as compared to control HDL. Furthermore, enrichment of the mouse HDL with rePON1 increased its ability to induce cholesterol efflux from J774A.1 macrophage cell line, and to inhibit macrophage-mediated LDL oxidation. In MPM from rePON1-injected mice vs. control MPM, there was a significant reduction in cholesterol mass, by 42%, in association with inhibition in cellular cholesterol biosynthesis rate, by 33%, and with significant stimulation, by 65%, of human HDL-mediated cholesterol efflux from the cells. We conclude that rePON1 injection to mice improved the mice HDL and MPM antiatherogenic properties, and these effects could probably lead to attenuation of atherosclerosis development.
ESTHER : Rosenblat_2011_Biofactors_37_462
PubMedSearch : Rosenblat_2011_Biofactors_37_462
PubMedID: 22162319

Title : Paraoxonase 1 (PON1) inhibits monocyte-to-macrophage differentiation - Rosenblat_2011_Atherosclerosis_219_49
Author(s) : Rosenblat M , Volkova N , Ward J , Aviram M
Ref : Atherosclerosis , 219 :49 , 2011
Abstract : OBJECTIVE: To analyze paraoxonase 1 (PON1) effect on monocyte-to-macrophage differentiation. METHODS AND
RESULTS: THP-1 monocytic cell-line and mouse peritoneal macrophages (MPM) were studied. Markers for monocytes differentiation included: morphological changes, CD11b and CD36 expression, and cellular oxidative stress. PON1KO MPM were more differentiated than control C57BL/6 MPM. Intraperitoneal injection of recombinant PON1 (rePON1) to C57BL/6 or to PON1KO mice significantly increased serum, MPM, and tissues PON1 activities. These effects were associated with a significant decrease in CD11b in C57BL/6 and PON1KO MPM (by 21% and 35%, respectively), in CD36 (by 35% and 38%, respectively), and in cellular total peroxides content (by 18% and 20%, respectively). rePON1 also significantly inhibited CD11b and CD36 expression, and cellular total peroxides during PMA-induced THP-1 monocytes differentiation, by 68%, 56% and 53%, respectively. Similar effects were observed upon using reconstituted HDL (rHDL) +rePON1, or human HDL +rePON1, in comparison to rHDL or to human HDL, as well as, HDL from C57BL/6 vs. PON1KO mice. Inhibition of monocyte-to-macrophage differentiation was demonstrated also by several dietary antioxidants such as vitamin E, gallic acid, or punicalagin (the major polyphenol in pomegranate). Whereas NADPH oxidase was not involved in PON1 anti-differentiation effect, mitochondrial complex I could be involved, as rotenone (complex I inhibitor) significantly decreased (by 77%) the expression of CD11b during THP-1 differentiation. Finally, blocking PON1 sulfhydryl group with N-ethylmalemide significantly attenuated PON1 inhibitory effect on THP-I monocyte-to-macrophage differentiation. CONCLUSION: HDL-associated PON1 inhibits monocyte-to-macrophage differentiation, and this effect could be related to PON1 peroxidase-like activity which involves its free sulfhydryl group.
ESTHER : Rosenblat_2011_Atherosclerosis_219_49
PubMedSearch : Rosenblat_2011_Atherosclerosis_219_49
PubMedID: 21798540

Title : Paraoxonase 1 attenuates human plaque atherogenicity: relevance to the enzyme lactonase activity - Tavori_2010_Adv.Exp.Med.Biol_660_99
Author(s) : Tavori H , Vaya J , Aviram M
Ref : Advances in Experimental Medicine & Biology , 660 :99 , 2010
Abstract : Human atherosclerotic lesions contain a variety of lipids and oxidized lipids, which can induce atherogenic properties such as macrophage oxidation, lipoprotein oxidation and inhibition of cholesterol efflux from macrophages. These atherogenic properties of the plaque's lipid fraction are associated with the inhibition of paraoxonase 1 (PON1) lactonase activity. In contrast, incubation of PON1 with the plaque's lipid fraction reduces the lesion's atherogenic properties by lowering the capacity of the oxidized lipids to induce further oxidation. The mechanism of PON1's protective action and its endogenous substrate however remain elusive. Modeling studies may characterize PON1's possible active site, and help envisage the structure of potential endogenous and exogenous lactones as PON1 ligands. Such modeling thus may lead to a better understanding of PON1's anti-atherogenic mechanism of action.
ESTHER : Tavori_2010_Adv.Exp.Med.Biol_660_99
PubMedSearch : Tavori_2010_Adv.Exp.Med.Biol_660_99
PubMedID: 20221874

Title : Paraoxonase 1 interactions with HDL, antioxidants and macrophages regulate atherogenesis - a protective role for HDL phospholipids - Efrat_2010_Adv.Exp.Med.Biol_660_153
Author(s) : Efrat M , Aviram M
Ref : Advances in Experimental Medicine & Biology , 660 :153 , 2010
Abstract : Macrophage cholesterol accumulation and foam cell formation is the hallmark of early atherogenesis. In addition to macrophages, at least three more major players regulate atherosclerosis development; paraoxonase 1 (PON1), antioxidants, and HDL. PON1 is an HDL-associated lactonase which posses antioxidant and anti-atherogenic properties. PON1 protects against macrophage-mediated LDL oxidation, and increases HDL binding to macrophages which, in turn, stimulates HDL's ability to promote cholesterol efflux. These two major anti-atherogenic properties of HDL (and of PON1) require, at least in part, macrophage binding sites for HDL-associated PON1. Indeed, PON1, as well as HDL-associated PON1, specifically binds to macrophages, leading to anti-atherogenic effects. Macrophage PON1 binding sites may thus be a target for future cardioprotection therapy. Studying the interactions among PON1, antioxidants, and macrophages can thus assist in achieving appropriate treatment and prevention of atherosclerosis.
ESTHER : Efrat_2010_Adv.Exp.Med.Biol_660_153
PubMedSearch : Efrat_2010_Adv.Exp.Med.Biol_660_153
PubMedID: 20221878

Title : Atherosclerosis: cell biology and lipoproteins--oxidative stress and paraoxonases regulate atherogenesis -
Author(s) : Aviram M
Ref : Curr Opin Lipidol , 21 :163 , 2010
PubMedID: 20616631

Title : Paraoxonase 1 (PON1) deficiency in mice is associated with reduced expression of macrophage SR-BI and consequently the loss of HDL cytoprotection against apoptosis - Fuhrman_2010_Atherosclerosis_211_61
Author(s) : Fuhrman B , Gantman A , Aviram M
Ref : Atherosclerosis , 211 :61 , 2010
Abstract : BACKGROUND: Paraoxonase 1 (PON1) was shown to stimulate HDL binding and HDL-mediated cholesterol efflux from macrophages. This study examined the role of PON1 in the expression of proteins that enhance macrophage HDL binding, i.e. ABCA1 and SR-BI. METHODS AND
RESULTS: ABCA1 expression was similar, whereas SR-BI expression (mRNA and protein determined by FACS, Western blot, or immunocytochemistry) was significantly decreased in peritoneal macrophages from PON1 deficient (MPM-PON1(0)) in comparison to C57Bl/6 (MPM-Control) mice. PON1 deficiency correction with HDL-control, recombinant PON1 (rePON1), or by transfection with a plasmid containing the rePON1 gene, increased SR-BI expression in MPM-PON1(0), whereas rePON1/H115Gln mutant, or the H115Q/H134Q double mutant, which lack catalytic activity, did not stimulate SR-BI expression. Lysophosphatidyl choline (LPC) resulting from PON1 action on macrophage PC, upregulated SR-BI expression in MPM-PON1(0) via activation of ERK1/2 and PI3K. Functionally, HDL bound to MPM-PON1(0) significantly less than to MPM-Control, and failed to inhibit tunicamycin-induced apoptosis, but had no significant effect on HDL-mediated cholesterol efflux from macrophages.
CONCLUSIONS: PON1 deficiency in mice is associated with decreased macrophage SR-BI expression, decreased cellular HDL binding, and consequently the loss of HDL-mediated cytoprotection against apoptosis, which may contribute to the accelerated atherosclerosis observed in PON1(0) mice. These findings add new insights into the function of SR-BI in macrophages, and define the potential role of PON1 in regulating SR-BI-mediated HDL protection against macrophages apoptosis.
ESTHER : Fuhrman_2010_Atherosclerosis_211_61
PubMedSearch : Fuhrman_2010_Atherosclerosis_211_61
PubMedID: 20149374

Title : Pomegranate juice polyphenols increase recombinant paraoxonase-1 binding to high-density lipoprotein: studies in vitro and in diabetic patients - Fuhrman_2010_Nutrition_26_359
Author(s) : Fuhrman B , Volkova N , Aviram M
Ref : Nutrition , 26 :359 , 2010
Abstract : OBJECTIVE: The high-density lipoprotein (HDL)-associated paraoxonase-1 (PON1)/free PON1 ratio is lower in diabetic patients in comparison with healthy controls. Because diabetes is associated with increased oxidative stress, we hypothesized that a labeled recombinant PON1 (rePON1) would detect differences in HDL capacity to bind PON1 under specific experimental conditions, such as oxidation, addition of polyphenols, or in vivo dosing of diabetic patients with polyphenols.
METHODS: In the present study we determined labeled rePON1 binding to HDL under various oxidative conditions by using polyacrylamide gel electrophoresis for the separation of free labeled rePON1 from HDL-bound labeled rePON1.
RESULTS: The HDL-rePON1/free rePON1 ratio gradually decreased as the extent of HDL oxidation increased, and the antioxidants vitamin E or pomegranate juice (PJ) inhibited the redistribution of rePON1. PJ or its purified polyphenols, punicalagin, gallic acid, or ellagic acid, increased rePON1 binding also to non-oxidized HDL. Further, rePON1 associated more efficiently with HDLs isolated from diabetic patients after PJ consumption versus HDLs isolated before PJ consumption.
CONCLUSIONS: We conclude that 1) oxidative stress impairs binding of fluorescein isothiocyanate-labeled rePON1 to HDL and 2) PJ polyphenols directly increase the HDL-rePON1 association beyond their antioxidative effect.
ESTHER : Fuhrman_2010_Nutrition_26_359
PubMedSearch : Fuhrman_2010_Nutrition_26_359
PubMedID: 19762215

Title : ApoE induces serum paraoxonase PON1 activity and stability similar to ApoA-I - Gaidukov_2010_Biochemistry_49_532
Author(s) : Gaidukov L , Viji RI , Yacobson S , Rosenblat M , Aviram M , Tawfik DS
Ref : Biochemistry , 49 :532 , 2010
Abstract : Serum paraoxonase (PON1) is an anti-atherogenic interfacially activated lipo-lactonase that was shown to selectively bind high-density lipoprotein (HDL) carrying apolipoprotein A-I (apoA-I). ApoA-I binding occurs with nanomolar affinity and induces a dramatic increase in enzyme stability and lactonase activity. This study examined the association of PON1 with reconstituted HDL (rHDL) carrying apolipoprotein E, and its consequences on the stability and enzymatic activity of PON1, and on its anti-atherogenic potential. The results indicate that reconstituted HDL particles prepared with two most common isoforms of apoE (apoE3 and apoE4) associate with rePON1 in a manner and affinity similar to those of apoA-I. Binding to apoE-HDL stimulates the lactonase activity and stabilizes the enzyme, although the latter occurs to a >10-fold lesser extent compared to apoA-I-HDL particles. The anti-atherogenic potential of PON1, measured by inhibition of LDL oxidation and stimulation of macrophage cholesterol efflux, was also stimulated by apoE-HDL, at levels of 40-96% compared to apoA-I-HDL. Overall, reconstituted apoE-HDL exhibits properties similar to those of apoA-I-HDL, but with a lower capacity to stabilize PON1 and to induce its anti-atherogenic functions. ApoE, apoA-I, and to a lesser degree apoA-IV show distinct structural and functional similarities but little sequence homology. That these apolipoproteins, but not apoA-II, bind PON1 with high affinity and stimulate its activity suggests that PON1-HDL recognition is based primarily on surface properties of the apolipoproteins and that specific protein-protein interactions may play only a secondary role.
ESTHER : Gaidukov_2010_Biochemistry_49_532
PubMedSearch : Gaidukov_2010_Biochemistry_49_532
PubMedID: 20025294

Title : Paraoxonase 1 deficiency in mice is associated with reduced steroid biosynthesis: effects on HDL binding, cholesteryl ester accumulation and scavenger receptor type BI expression - Gamliel-Lazarovich_2010_Atherosclerosis_211_130
Author(s) : Gamliel-Lazarovich A , Gantman A , Shiner M , Coleman R , Aviram M , Keidar S
Ref : Atherosclerosis , 211 :130 , 2010
Abstract : OBJECTIVE: Selective uptake of high density lipoprotein (HDL) cholesteryl ester (CE) is considered as the major source of cholesterol for production of steroids in the adrenal gland in rodents. As paraoxonase 1 (PON1) is an HDL-associated lipo-lactonase that has been shown to increase binding of HDL to macrophages, we used PON1 knock-out (PON1KO) mice to test the possible role of PON1 in corticosterone (CS) biosynthesis. METHODS AND
RESULTS: PON1 deficiency was associated with reduced serum CS concentration. Adrenal glands obtained from PON1KO mice had significantly lower CE content compared to adrenals from C57Bl6 control mice. Binding of HDL obtained from PON1KO mice to human adrenocortical carcinoma cell line was found to be significantly lower than that of control HDL, and was associated with decreased CS biosynthesis. Addition of purified PON1 to HDL from PON1KO mice increased HDL binding and CS synthesis. Furthermore, the expression of the HDL receptor, SR-BI, protein and mRNA, was reduced in adrenals from PON1KO mice compared to control mice. When challenged with low salt diet, PON1KO mice demonstrated an increase in adrenal SR-BI gene expression and in serum corticosterone which reached levels similar to those obtained in control mice. CONCLUSION: PON1 regulates adrenal CS biosynthesis at two levels: (a) via an accessory role in HDL binding properties, and (b) a supportive role in SR-BI expression and CE supply to the cells.
ESTHER : Gamliel-Lazarovich_2010_Atherosclerosis_211_130
PubMedSearch : Gamliel-Lazarovich_2010_Atherosclerosis_211_130
PubMedID: 20189567

Title : Consumption of polyphenolic-rich beverages (mostly pomegranate and black currant juices) by healthy subjects for a short term increased serum antioxidant status, and the serum's ability to attenuate macrophage cholesterol accumulation - Rosenblat_2010_Food.Funct_1_99
Author(s) : Rosenblat M , Volkova N , Attias J , Mahamid R , Aviram M
Ref : Food Funct , 1 :99 , 2010
Abstract : The present study analyzed the antioxidative effects of various beverages, in vitro, and also the effect of short term consumption of beverages richest in polyphenols by healthy subjects on serum anti-atherogenic properties. Healthy subjects consumed 250 mL of the selected beverages for 2 h, or daily, for up to 1 week.We hypothesized that differences in the anti-atherogenic properties of the studied beverages could be related, not only to the quantity of polyphenols, but also to their quality. Furthermore, we hypothesized that consumption of these juices by healthy subjects for just a short-term, will increase their serum anti-atherogenic properties, as was demonstrated previously in long-term consumption studies.Of 35 beverages studied, both 100% Wonderful-variety pomegranate and 100% black currant juices were the most potent antioxidants in vitro, as they inhibited copper ion-induced LDL oxidation by up to 94% and AAPH-induced serum lipid peroxidation by up to 38%. Furthermore, they increased in vitro serum paraoxonase 1 (PON1) lactonase activity by up to 51%. Consumption of five selected polyphenol rich beverages by healthy subjects increased serum sulfhydryl group (SH) levels and serum PON1 activities after 2 h, and more so after 1 week of drinking these beverages. These effects were most pronounced after the consumption of 100% Wonderful-variety pomegranate and 100% black currant juices. In conclusion, polyphenolic-rich juices with impressive in vitro antioxidant properties, also demonstrate antioxidant effects in vivo when analyzed for short term consumption. In this respect, 100% Wonderful-variety pomegranate and 100% black currant juices were most the potent.
ESTHER : Rosenblat_2010_Food.Funct_1_99
PubMedSearch : Rosenblat_2010_Food.Funct_1_99
PubMedID: 21776460

Title : Macrophage endoplasmic reticulum (ER) proteins and reducing elements stabilize paraoxonase 2 (PON2) - Rosenblat_2010_Atherosclerosis_213_408
Author(s) : Rosenblat M , Volkova N , Aviram M
Ref : Atherosclerosis , 213 :408 , 2010
Abstract : OBJECTIVE: To analyze the ability of macrophage sub-cellular fractions to stabilize paraoxonase 2 (PON2).
METHODS: Nuclei, mitochondria, lysosomes, endoplasmic reticulum (ER) and cytosol were isolated from J774A.1 macrophage cell line and incubated with recombinant PON2.
RESULTS: Among the fractions analyzed the ER contains the highest PON2 lactonase activity, and was the most potent one in stabilizing recombinant PON2 (rePON2). Whereas control rePON2 activity was decreased by 40% after 20 h of incubation at 37 degrees C, in the presence of ER it decreased by only 15%. This effect could be attributed to the ER aqueous phase, and not to the ER lipids. The ER proteins fraction was responsible for PON2 stabilization, since heated ER or proteinase K-treated ER was not able to protect rePON2 from inactivation, while the protein fraction (after ammonium sulfate precipitation) completely prevented rePON2 inactivation. Since in the macrophage ER, there are increased levels of NADPH, secondary to glutathione reductase deficiency, we next studied the effect of the redox environment on PON2 inactivation. Incubation of rePON2 with DTT protected PON2 from inactivation. Similarly, NADPH, but not NADP, significantly increased rePON2 lactonase activity by up to 19%, after 20h of incubation as compared to control rePON2. Unlike ER from non-treated macrophages, ER harvested from oxidized-, or from cholesterol loaded-macrophages showed a significant lower basal PON2 lactonase activity, and did not protect PON2 from inactivation but rather increased it. CONCLUSION: Under normal conditions macrophage ER stabilizes PON2 activity, and this effect could be attributed to ER proteins and redox status.
ESTHER : Rosenblat_2010_Atherosclerosis_213_408
PubMedSearch : Rosenblat_2010_Atherosclerosis_213_408
PubMedID: 21036357

Title : Pomegranate juice (PJ) consumption antioxidative properties on mouse macrophages, but not PJ beneficial effects on macrophage cholesterol and triglyceride metabolism, are mediated via PJ-induced stimulation of macrophage PON2 - Rosenblat_2010_Atherosclerosis_212_86
Author(s) : Rosenblat M , Volkova N , Aviram M
Ref : Atherosclerosis , 212 :86 , 2010
Abstract : OBJECTIVE: To examine whether the beneficial effects of PJ consumption by mice on their macrophages are mediated via PJ-induced increment in serum paraoxonase 1 (PON1) activity and/or in macrophage PON2 expression. METHODS AND
RESULTS: We performed studies in peritoneal macrophages (MPM) from C57BL/6 control mice, or from PON1KO mice, or from PON2KO mice that consumed PJ (200 microg of gallic acid equivalents/mouse/day, for 1 month period). PJ consumption by C57BL/6 mice resulted in a significant increment, by 36% in serum PON1 catalytic activities, and upregulated MPM PON2 expression. In MPM from C57BL/6 or from PON1KO mice that consumed PJ, the extent of cell-mediated LDL oxidation was decreased by 22%, and that of cellular superoxide release by 20-26%. In contrast, PJ consumption by PON2KO mice resulted in a minimal inhibitory effect on macrophage oxidative stress by only 4-9%. Unlike PJ antioxidative effects in MPM, PJ anti-atherogenic effects on MPM cholesterol and triglyceride metabolism were similar in all mice groups that consumed PJ. After PJ consumption, cellular cholesterol content was decreased by 14-19%, and this could be attributed to a significant inhibition in MPM cholesterol biosynthesis rate by 20-32%, and/or to stimulation of HDL-mediated cholesterol efflux from the cells by 22-37%. Similarly, MPM triglyceride content and triglyceride biosynthesis rate were both significantly decreased after PJ consumption, by 16-27% and by 22-28%, respectively. CONCLUSION: PJ consumption antioxidative properties on mouse macrophages, but not PJ beneficial effects on macrophage cholesterol and triglyceride metabolism, are mediated via PJ-induced stimulation of macrophage PON2 expression. Serum PON1 stimulation by PJ consumption, however, was not involved in PJ-induced effects on macrophages.
ESTHER : Rosenblat_2010_Atherosclerosis_212_86
PubMedSearch : Rosenblat_2010_Atherosclerosis_212_86
PubMedID: 20537330

Title : Increased macrophage cholesterol biosynthesis and decreased cellular paraoxonase 2 (PON2) expression in Delta6-desaturase knockout (6-DS KO) mice: beneficial effects of arachidonic acid - Rosenblat_2010_Atherosclerosis_210_414
Author(s) : Rosenblat M , Volkova N , Roqueta-Rivera M , Nakamura MT , Aviram M
Ref : Atherosclerosis , 210 :414 , 2010
Abstract : OBJECTIVE: To analyze the possible role of arachidonic acid (AA) in macrophage cholesterol biosynthesis and in PON2 expression. METHODS AND
RESULTS: We used peritoneal macrophages (MPM) from the 6-DS KO mice that were fed a diet without or with AA. Macrophage cholesterol biosynthesis rate and HMGCoA-reductase mRNA levels were substantially increased, by 98% and 67%, respectively, in MPM from 6-DS KO vs. control (C57BL/6) mice. Furthermore, in the 6-DS KO vs. control mice MPM PON2 expression (mRNA and lactonase activity) was substantially decreased. In line with the above results, AA supplementation to 6-DS KO mice significantly decreased MPM cholesterol biosynthesis rate and HMGCoA-reductase mRNA levels, by 45% and by 4-fold respectively, and increased MPM PON2 lactonase activity and PON2 mRNA, by 119% and 2.3-fold, respectively. Similarly, incubation of control mice MPM or J774A.1 with AA, significantly and dose-dependently decreased cellular cholesterol biosynthesis rate, and increased PON2 expression. These effects were specific for AA since incubation of the cells with docosahexaenoic acid (DHA, another product of 6-DS) had no significant effects on cholesterol biosynthesis rate, and on PON2 activity.
CONCLUSIONS: AA decreased macrophage cholesterol biosynthesis rate, and increased PON2 expression. These effects could protect the cells from cholesterol accumulation and oxidation, and from foam cell formation, the hallmark of early atherogenesis.
ESTHER : Rosenblat_2010_Atherosclerosis_210_414
PubMedSearch : Rosenblat_2010_Atherosclerosis_210_414
PubMedID: 20042190

Title : Paraoxonase 2 (PON2) decreases high glucose-induced macrophage triglycerides (TG) accumulation, via inhibition of NADPH-oxidase and DGAT1 activity: studies in PON2-deficient mice - Meilin_2010_Atherosclerosis_208_390
Author(s) : Meilin E , Aviram M , Hayek T
Ref : Atherosclerosis , 208 :390 , 2010
Abstract : OBJECTIVE: The present study investigates the role of paraoxonase 2 (PON2) in the attenuation of macrophage triglycerides (TG) biosynthesis, and oxidative stress, under diabetic conditions.
METHODS: Peritoneal macrophages (MPM) from PON2-deficient and from C57BL/6 control mice were harvested and cultured under normal (5mM) or high glucose concentration (30mM), and evaluated for cellular TG metabolism as well as for their oxidative stress.
RESULTS: In PON2-deficient MPM vs. control MPM, under diabetic conditions (high glucose concentration), we observed substantial increment in TG accumulation (3 fold), TG biosynthesis (2.6 fold) and microsomal diacylglycerol acyltransferase1 (DGAT1) activity (+60%). Furthermore, in these cells we have demonstrated increased oxidative stress, as expressed by significant increment in cellular oxidative stress (+25%), macrophage-mediated LDL oxidation (+41%) and expression of the receptor for advanced glycation end products - RAGE (+18%). Apocynin, an NADPH-oxidase inhibitor, abolished the increment in MPM TG accumulation, MPM TG biosynthesis, and microsomal DGAT1 activity, as a result of PON2-deficiency, under diabetic conditions. CONCLUSION: We conclude that PON2 has a significant protective role against macrophage triglyceride accumulation, macrophage TG biosynthesis, microsomal DGAT1 activity and macrophage oxidative stress, under high glucose concentrations. We suggest that this protective effect may be mediated by PON2 through the attenuation of NADPH-oxidase activity. The use of appropriate means to increase macrophage PON2 expression can lead to attenuation in macrophage TG accumulation and in cellular oxidative stress, under diabetic conditions, and thus may contribute to the decrement in macrophage atherogenicity and foam cell formation, attenuating the development of vascular complications in diabetes mellitus.
ESTHER : Meilin_2010_Atherosclerosis_208_390
PubMedSearch : Meilin_2010_Atherosclerosis_208_390
PubMedID: 19748094

Title : Paraoxonase 1 (PON1) expression in hepatocytes is upregulated by pomegranate polyphenols: a role for PPAR-gamma pathway - Khateeb_2010_Atherosclerosis_208_119
Author(s) : Khateeb J , Gantman A , Kreitenberg AJ , Aviram M , Fuhrman B
Ref : Atherosclerosis , 208 :119 , 2010
Abstract : OBJECTIVE: Serum paraoxonase-1 (PON1) expression is regulated by polyphenols, shown to activate the peroxisome proliferator-activated receptor gamma (PPARgamma). Pomegranate juice (PJ) is a polyphenol-rich fruit. Because promoter sequence of PON1 gene indicates that it could be regulated by nuclear receptors, we investigated the effect of PJ polyphenols on PON1 gene expression in HuH7 hepatocytes. METHODS AND
RESULTS: PON1 protein or mRNA expression, determined by immunocytochemistry, or quantitative PCR, respectively, as well as PON1 gene promoter activation, was significantly increased in hepatocytes incubated with PJ or with its major polyphenols punicalagin, or gallic acid (GA). Ellagic acid (EA) elicited only modest stimulatory effect. Accordingly, PJ, punicalagin, GA, and less so EA, dose-dependently increased cell-associated and hepatocyte-secreted PON1 arylesterase activity. Functionally, the secreted PON1 exhibited biological activity by protecting LDL and HDL from oxidation. Finally, PJ polyphenols upregulated the hepatocyte PON1 expression, at least in part, via the intracellular signaling cascade PPARgamma-PKA-cAMP.
CONCLUSIONS: This study shows for the first time that PJ polyphenols have a specific transcriptional role in hepatocyte PON1 expression upregulation, and its secretion to the medium. We conclude that the anti-atherogenic characteristics of PJ polyphenols are modulated, at least in part, via hepatocyte PON1 upregulation and its subsequent release to the medium.
ESTHER : Khateeb_2010_Atherosclerosis_208_119
PubMedSearch : Khateeb_2010_Atherosclerosis_208_119
PubMedID: 19783251

Title : Directed evolution of serum paraoxonase PON3 by family shuffling and ancestor\/consensus mutagenesis, and its biochemical characterization - Khersonsky_2009_Biochemistry_48_6644
Author(s) : Khersonsky O , Rosenblat M , Toker L , Yacobson S , Hugenmatter A , Silman I , Sussman JL , Aviram M , Tawfik DS
Ref : Biochemistry , 48 :6644 , 2009
Abstract : Serum paraoxonases (PONs) are calcium-dependent lactonases with anti-atherogenic and detoxification functions. Here we describe the directed evolution and characterization of recombinant variants of serum paraoxonase PON3 that express in an active and soluble manner in Escherichia coli. These variants were obtained by combining family shuffling and phylogeny-based mutagenesis: the limited diversity of accessible, cloned PON3 genes was complemented by spiking the shuffling reaction with ancestor/consensus mutations, mutations to residues that comprise the consensus or appear in the predicted ancestors of the PON family. We screened the resulting libraries for PON3's lactonase activity while ensuring that the selected variants retained the substrate specificity of wild-type mammalian PON3s. The availability of highly stable, recombinant PON3 that is free of all other serum components enabled us to explore unknown biochemical features of PON3, including its binding to HDL particles, the effect of HDL on PON3's stability and enzymatic activity, and ex vivo tests of its anti-atherogenic properties. Overall, it appears that PON3 possesses properties very similar to those of PON1: the enzyme's lactonase activity is selectively stimulated by binding to apoAI-HDL, with a concomitant increase in its stability. PON3 also exhibits potentially anti-atherogenic functions, although at levels lower than those of PON1.
ESTHER : Khersonsky_2009_Biochemistry_48_6644
PubMedSearch : Khersonsky_2009_Biochemistry_48_6644
PubMedID: 19492856

Title : Human carotid atherosclerotic plaque increases oxidative state of macrophages and low-density lipoproteins, whereas paraoxonase 1 (PON1) decreases such atherogenic effects - Tavori_2009_Free.Radic.Biol.Med_46_607
Author(s) : Tavori H , Aviram M , Khatib S , Musa R , Nitecki S , Hoffman A , Vaya J
Ref : Free Radic Biol Med , 46 :607 , 2009
Abstract : Human atherosclerotic plaque contains a variety of oxidized lipids, which can facilitate further oxidation. Paraoxonase 1 (PON1) is a high-density lipoprotein (HDL)-associated esterase (lipolactonase), exhibiting antiatherogenic properties. The aims of the present study were to examine the oxidizing potency of the human carotid plaque lipid extract (LE), and the antiatherogenic role of PON1 on LE oxidation competence. Human carotid plaques were extracted by organic solvent, and the extract was incubated with lipoprotein particles, with macrophages, or with probes sensitive to oxidative stress, with or without preincubation with PON1, followed by oxidative-stress assessment. Our findings imply that the LE oxidized LDL, macrophages, and exogenous probes and decreases HDL-mediated cholesterol efflux from macrophages, in a dose-dependent manner. Incubation of PON1 with LE significantly affects LE composition, reduces LE atherogenic properties, and decreases the extract's total peroxide concentration by 44%, macrophage oxidation by 25%, and probe oxidation by up to 52%. We conclude that these results expand our understanding of how the plaque itself accelerates atherogenesis and provides an important mechanism for attenuation of atherosclerosis development by the antioxidant action of PON1 on the atherosclerotic plaque.
ESTHER : Tavori_2009_Free.Radic.Biol.Med_46_607
PubMedSearch : Tavori_2009_Free.Radic.Biol.Med_46_607
PubMedID: 19103284

Title : Di-oleoyl phosphatidylcholine (PC-18:1) stimulates paraoxonase 1 (PON1) enzymatic and biological activities: in vitro and in vivo studies - Efrat_2009_Atherosclerosis_202_461
Author(s) : Efrat M , Rosenblat M , Mahmood S , Vaya J , Aviram M
Ref : Atherosclerosis , 202 :461 , 2009
Abstract : OBJECTIVE: Paraoxonase 1 (PON1) is a high-density lipoprotein (HDL)-associated enzyme which possess anti-atherogenic properties. Our aim was to analyze the effect of HDL phospholipids on HDL-associated paraoxonase (PON1) catalytic and biological activities. METHODS AND
RESULTS: In HDL isolated from di-oleoyl-phosphatidylcholine (PC-18:1)-enriched serum, HDL-PC-18:1 levels, as well as PON1 lactonase, arylesterase and paraoxonase activities were increased by 23%, 35%, 47% and 63%, respectively, as compared to control HDL (p<0.01). Furthermore, PON1 contribution to HDL-mediated cholesterol efflux from J774A.1 macrophages was higher in PC-18:1-enriched HDL in comparison to control HDL. In vivo olive oil consumption by Balb C mice increased HDL phospholipids/protein (30%), and HDL-PON1 arylesterase (150%) and lactonase (94%) activities (p<0.01). Furthermore, in the olive oil-treated mice PON1 contribution to HDL-mediated macrophage cholesterol efflux was higher by 100%, in comparison to placebo mouse HDL (p<0.01). Similarly, olive oil consumption by healthy subjects increased HDL-PC-18:1 levels, HDL-PON1 arylesterase (88%), lactonase (52%), paraoxonase (140%) activities and PON1 stimulatory effect on HDL-mediated cholesterol efflux (53%) as compared to HDL before treatment (p<0.01). PC-18:1 stimulatory effect on recombinant PON1 mutant (lacks 20 amino acids at the N-terminal region) paraoxonase and lactonase activities was lower by 56% and 57%, respectively, in comparison to its effect on wild type PON1 (p<0.01). CONCLUSION: Intervention to increase PON1 activities by HDL enrichment with PC-18:1 could be proven as a beneficial anti-atherogenic therapy.
ESTHER : Efrat_2009_Atherosclerosis_202_461
PubMedSearch : Efrat_2009_Atherosclerosis_202_461
PubMedID: 18585720

Title : Effects of date ( Phoenix dactylifera L., Medjool or Hallawi Variety) consumption by healthy subjects on serum glucose and lipid levels and on serum oxidative status: a pilot study - Rock_2009_J.Agric.Food.Chem_57_8010
Author(s) : Rock W , Rosenblat M , Borochov-Neori H , Volkova N , Judeinstein S , Elias M , Aviram M
Ref : Journal of Agricultural and Food Chemistry , 57 :8010 , 2009
Abstract : The present pilot study analyzed, for the first time, the in vivo effect of Medjool or Hallawi date consumption by healthy subjects on serum glucose, lipids, and oxidative stress. Total phenolics concentration in the Hallawi versus Medjool dates was greater by 20-31%. The major proportion of the soluble phenolics in both date varieties consisted of phenolic acids, mainly ferulic acid and coumaric acid derivatives, and also chlorogenic and caffeic acid derivatives. Unlike the Medjool dates, Hallawi dates contained a significant proportion of catechins as well. In addition, both varieties contained a quercetin derivative. Both date varieties possess antioxidative properties in vitro, but the ferric ion reducing antioxidant power of Hallawi versus Medjool dates was higher by 24%. Ten healthy subjects consumed, for a period of 4 weeks 100 g/day of either Medjool or Hallawi dates. The date consumption did not significantly affect the subjects' body mass index (BMI), their serum total cholesterol, or their cholesterol levels in the VLDL, LDL, or HDL fractions. Most important, fasting serum glucose and triacylglycerol levels were not increased after consumption of either date variety, and serum triacylglycerol levels even significantly (p < 0.05) decreased, by 8 or 15% after Medjool or Hallawi date consumption, respectively. Basal serum oxidative status was significantly (p < 0.01) decreased by 33%, as compared to the levels observed before consumption, after Hallawi (but not Medjool) date consumption. Similarly, the susceptibility of serum to AAPH-induced lipid peroxidation decreased by 12%, but only after Hallawi date consumption. In agreement with the above results, serum activity of the HDL-associated antioxidant enzyme paraoxonase 1 (PON1) significantly increased, by 8%, after Hallawi date consumption. It is concluded that date consumption (and mainly the Hallawi variety) by healthy subjects, despite their high sugar content, demonstrates beneficial effects on serum triacylglycerol and oxidative stress and does not worsen serum glucose and lipid/lipoprotein patterns, and thus can be considered an antiatherogenic nutrient .
ESTHER : Rock_2009_J.Agric.Food.Chem_57_8010
PubMedSearch : Rock_2009_J.Agric.Food.Chem_57_8010
PubMedID: 19681613

Title : Urokinase activates macrophage PON2 gene transcription via the PI3K\/ROS\/MEK\/SREBP-2 signalling cascade mediated by the PDGFR-beta - Fuhrman_2009_Cardiovasc.Res_84_145
Author(s) : Fuhrman B , Gantman A , Khateeb J , Volkova N , Horke S , Kiyan J , Dumler I , Aviram M
Ref : Cardiovascular Research , 84 :145 , 2009
Abstract : AIMS: We have recently shown that urokinase plasminogen activator (uPA) increases oxidative stress (OS), cholesterol biosynthesis, and paraoxonase 2 (PON2) expression in macrophages via binding to its receptor, the uPAR. Since PON2 is regulated by both OS and cholesterol content, we hypothesized that uPA elicits a cascade of signal transduction events shared by NADPH oxidase and cholesterol biosynthesis that culminates in PON2 gene expression. Here, we investigated the signalling pathway that leads to the expression of PON2 in macrophages in response to uPA. METHODS AND
RESULTS: The increase in macrophage PON2 mRNA levels in response to uPA was shown to depend on PON2 gene promoter activation and mRNA transcription. LDL abolished these effects, suggesting a possible role for a transcription factor involved in cellular cholesterogenesis. Indeed, uPA upregulated PON2 expression in a sterol regulatory binding protein-2 (SREBP-2)-dependent manner, since blocking SREBP-2 maturation by 4-(2-aminoethyl)-benzenesulfonyl fluoride abolished uPA-stimulation of PON2, whereas inhibition of SREBP-2 catabolism by N-acetyl-leucyl-norleucinal had an opposite effect. The upstream signalling mechanisms include uPA activation of extracellular signal-regulated kinases (ERK1/2), which was dependent on NADPH oxidase and phosphatidylinositol 3-kinase activation, and these latter effects were mediated by the tyrosine kinase activity of the platelet-derived growth factor receptor-beta. CONCLUSION: These findings provide a framework linking interactions among cellular signalling pathways associated with reactive oxygen species production, macrophage cholesterol biosynthesis, and cellular PON2 expression in vascular pathophysiology.
ESTHER : Fuhrman_2009_Cardiovasc.Res_84_145
PubMedSearch : Fuhrman_2009_Cardiovasc.Res_84_145
PubMedID: 19497963

Title : Paraoxonases role in the prevention of cardiovascular diseases - Rosenblat_2009_Biofactors_35_98
Author(s) : Rosenblat M , Aviram M
Ref : Biofactors , 35 :98 , 2009
Abstract : Increased oxidative stress is a characteristic of patients with high risk for atherosclerosis development (hypercholesterolemic, hypertensive, diabetic), and the above phenomenon was shown to be associated with attenuated antioxidative status. The increased oxidative stress in atherosclerotic patients is present in their blood, as well as in their arterial wall cells, including macrophages, the hallmark of foam cells formation during early atherogenesis. Serum high density lipoprotein (HDL)-associated paraoxonase 1 (PON1) reduces oxidative stress in lipoproteins, in macrophages, and in the atherosclerotic lesion, whereas paraoxonase 2 (PON2, which is present in tissues, but not in serum) acts as an antioxidant at the cellular and not humoral level. Both PON1 and PON2 protect against atherosclerosis development, and this phenomenon could be related to their antioxidative properties. The use of nutritional antioxidants such as vitamin E, carotenoids (lycopene and beta-carotene), and mainly polyphenols (such as those present in red wine, licorice root ethanolic extract, or in pomegranate) by atherosclerotic animals and also by cardiovascular patients, leads to a reduction in oxidative stress and to the attenuation of atherosclerosis development. These latter phenomena could be related to the nutritional antioxidants-induced increase in HDL PON1 activity (effects on gene expression, on preventing enzyme inactivation, and on increasing PON1 stability through its binding to HDL), as well as an increase in macrophage PON2 activation (at the gene expression level).
ESTHER : Rosenblat_2009_Biofactors_35_98
PubMedSearch : Rosenblat_2009_Biofactors_35_98
PubMedID: 19319852

Title : Paraoxonase 2 attenuates macrophage triglyceride accumulation via inhibition of diacylglycerol acyltransferase 1 - Rosenblat_2009_J.Lipid.Res_50_870
Author(s) : Rosenblat M , Coleman R , Reddy ST , Aviram M
Ref : J Lipid Res , 50 :870 , 2009
Abstract : This study questioned the role of paraoxonase 2 (PON2) in attenuation of macrophage lipids accumulation. Mouse peritoneal macrophages (MPMs) harvested from PON2-deficient mice versus control C57BL/6 mice, look like foam cells and were larger in size and filled with lipid droplets. Macrophage triglyceride (but not cholesterol) content, biosynthesis rate, and microsomal acyl-CoA:diacylglycerol acyltransferase 1 (DGAT1) activity (not mRNA and protein) in PON2-deficient versus control MPM were all significantly increased by 4.6-, 3.6-, and 4.4-fold, respectively. Similarly, microsomal DGAT1 activity and cellular triglyceride content were significantly decreased in human PON2-transfected cells as well as upon incubation of PON2-deficient MPM with recombinant PON2. In all the above experimental systems, PON2 also decreased macrophage oxidative state. Incubation of PON2-deficient MPM with the free radicals generator 2,2'-amidinopropane hydrochloride increased cellular oxidative stress and DGAT1 activity by 2.2- and 3.4-fold, respectively, whereas incubation of microsomes from PON2-deficient MPM with superoxide dismutase decreased DGAT1 activity by 40%. We thus conclude that PON2 attenuates macrophage triglyceride accumulation and foam cell formation via inhibition of microsomal DGAT1 activity, which appears to be sensitive to oxidative state.
ESTHER : Rosenblat_2009_J.Lipid.Res_50_870
PubMedSearch : Rosenblat_2009_J.Lipid.Res_50_870
PubMedID: 19091699

Title : Macrophages from alpha 7 nicotinic acetylcholine receptor knockout mice demonstrate increased cholesterol accumulation and decreased cellular paraoxonase expression: a possible link between the nervous system and atherosclerosis development - Wilund_2009_Biochem.Biophys.Res.Commun_390_148
Author(s) : Wilund KR , Rosenblat M , Chung HR , Volkova N , Kaplan M , Woods JA , Aviram M
Ref : Biochemical & Biophysical Research Communications , 390 :148 , 2009
Abstract : OBJECTIVE: The parasympathetic nervous system regulates inflammation in peripheral tissues through a pathway termed the "cholinergic anti-inflammatory reflex" (CAIR). Mice deficient in the alpha 7 nicotinic acetylcholine receptor (alpha7(-/-)) have an impaired CAIR due to decreased signaling through this pathway. The purpose of this study was to determine if the increased inflammation in alpha7(-/-) mice is associated with enhanced serum and macrophage atherogenicity.
METHODS: We measured serum markers of inflammation and oxidative stress, and macrophage atherogenicity in mouse peritoneal macrophages harvested from alpha7(-/-) mice on the background of C57BL/6 mice, as well as on the background of the atherosclerotic Apolipoprotein E-deficient (ApoE(-/-)) mice.
RESULTS: alpha7-Deficiency had no significant effects on serum cholesterol, or on markers of serum oxidative stress (TBARS and paraoxonase1 activities). However, alpha7-deficiency significantly increased serum CRP and IL-6 (p<0.05) levels in atherosclerotic mice, confirming an anti-inflammatory role for the alpha7 receptor. Macrophage cholesterol mass was increased by 25% in both normal and atherosclerotic mice in the absence of the alpha7 receptor (p<0.05). This was accompanied by conditional increases in oxidized LDL uptake and in macrophage total peroxide levels. Furthermore, alpha7-deficiency reduced macrophage paraoxonase2 mRNA and activity by 50-100% in normal and atherosclerotic mice (p<0.05 for each), indicating a reduction in macrophage anti-oxidant capacity in the alpha7(-/-) mice. CONCLUSION: The above results suggest an anti-atherogenic role for the macrophage alpha7nAchr, through a mechanism that involves attenuated macrophage oxidative stress and decreased uptake of oxidized LDL.
ESTHER : Wilund_2009_Biochem.Biophys.Res.Commun_390_148
PubMedSearch : Wilund_2009_Biochem.Biophys.Res.Commun_390_148
PubMedID: 19785985

Title : Lipid profile and serum characteristics of the blind subterranean mole rat, Spalax - Nasser_2009_PLoS.One_4_e4528
Author(s) : Nasser NJ , Kaplan M , Nevo E , Aviram M
Ref : PLoS ONE , 4 :e4528 , 2009
Abstract : BACKGROUND: Spalax (blind subterranean mole rat), is a mammal adapted to live in fluctuating oxygen levels, and can survive severe hypoxia and hypercapnia. The adaptive evolution of Spalax to underground life resulted in structural and molecular-genetic differences comparing to above-ground mammals. These differences include higher myocardial maximal oxygen consumption, increased lung diffusion capacity, increased blood vessels density, and unique expression patterns of cancer and angiogenesis related genes such as heparanase, vascular endothelial growth factor, and P53. METHODOLOGY/PRINCIPAL FINDINGS: Here we elucidate the main characteristics of Spalax lipid profile, as well as its main antioxidant and serum parameters. Compared to human, Spalax possesses lower total-cholesterol, low density lipoproteins (LDL) and triglycerides levels, and higher levels of high density lipoproteins (HDL). Apolipoprotein A-I and apolipoprotein B-100 were significantly lower in Spalax compared to human. Paraoxonase (PON) 1 arylesterase activity, was higher in Spalax compared to both human and mouse serum levels. Analysis of serum chemistry of Spalax revealed special features in this mammal. CONCLUSIONS/SIGNIFICANCE: Spalax possesses a unique lipid profile with high HDL and low LDL lipoproteins. The antioxidant serum content in the mole rat is higher than that of human and mouse. Serum C reactive protein (CRP) levels are significantly lower in Spalax compared to that of human or mouse, reflecting low levels of inflammation. These differences between Spalax, human and mouse are due to several factors including the intensive activity life-style that Spalax pursue underground, dietary components, and evolutionary genetic adaptations. Unfolding the genetic basis of these differences will probably result in unique treatments for a variety of human diseases such as dyslipedemias, inflammation and cancer.
ESTHER : Nasser_2009_PLoS.One_4_e4528
PubMedSearch : Nasser_2009_PLoS.One_4_e4528
PubMedID: 19229331

Title : Characterization of the PON1 active site using modeling simulation, in relation to PON1 lactonase activity - Tavori_2008_Bioorg.Med.Chem_16_7504
Author(s) : Tavori H , Khatib S , Aviram M , Vaya J
Ref : Bioorganic & Medicinal Chemistry , 16 :7504 , 2008
Abstract : Paraoxonase1 (PON1) is a HDL bound enzyme and many of the anti-atherogenic properties of HDL are attributed to PON1. The enzyme precise mechanism of protective action and its endogenous substrate remain elusive. PON1 hydrolyzes organophosphates, arylesters and lactones, whereas the lactones activity is assumed as the physio/pathological one. This study is aimed to predict the location of the PON1 active site within PON1 crystal structure, and the lactone structure suitability as PON1 ligand, by employing modeling techniques. Based on such calculations the ligands-PON1 interactions were characterized, and relating lactones rate of hydrolysis revealed an inverse correlation with the docking energy of the ligands-PON1 complex, and a direct correlation with the lactone side chain length. In conclusion, this study characterized the PON1 possible active site and proposes a tool which may make it possible to envisage the structure of potential endogenous and exogenous lactones such as the PON1 ligand.
ESTHER : Tavori_2008_Bioorg.Med.Chem_16_7504
PubMedSearch : Tavori_2008_Bioorg.Med.Chem_16_7504
PubMedID: 18572410

Title : Macrophage paraoxonase 1 (PON1) binding sites - Efrat_2008_Biochem.Biophys.Res.Commun_376_105
Author(s) : Efrat M , Aviram M
Ref : Biochemical & Biophysical Research Communications , 376 :105 , 2008
Abstract : Paraoxonase 1 (PON1), an HDL-associated esterase, is known to possess anti-oxidant and anti-atherogenic properties. PON1 was shown to protect macrophages from oxidative stress, to inhibit macrophage cholesterol biosynthesis, and to stimulate HDL-mediated cholesterol efflux from the cells. The aim of the present study was to characterize macrophage PON1 binding sites which could be responsible for the above anti-atherogenic activities. Incubation of FITC-labeled recombinant PON1 with J774 A.1 macrophage-like cell line at 37 degrees C, resulted in cellular binding and internalization of PON1, leading to PON1 localization in the cell's cytoplasm compartment. In order to determine whether PON1 uptake is mediated via a specific binding to the macrophage, FITC-labeled recombinant PON1 was incubated with macrophages at 4 degrees C, followed by cell membranes separation. Macrophage membrane fluorescence was shown to be directly and dose-dependently related to the labeled PON1 concentration. Furthermore, binding assays performed at 4 and at 37 degrees C, using labeled and non-labeled recombinant PON1 (for competitive inhibition), demonstrated a dose-dependent significant 30% decrement in labeled PON1 binding to the macrophages, by the non-labeled PON1. Similarly, binding assays, using labeled PON1 and non-labeled HDL (the natural carrier of PON1 in the circulation) indicated that HDL decreased the binding of labeled PON1 to macrophages by 25%. Unlike HDL, LDL had no effect on labeled PON1 binding to macrophages. Finally, HDL were pre incubated without or with PON1 or apolipoprotein AI (apoAI) antibodies, in order to block PON1 or apoAI ability to bind to the cells. HDL incubation with antibody to PON1 or to apoAI significantly decreased HDL ability to inhibit macrophages-mediated LDL oxidation (by 32% or by 25%, respectively). A similar trend was also observed for HDL-mediated cholesterol efflux from macrophages, with an inhibitory effect of 35% or 19%, respectively. These results suggest that blocking HDL binding to macrophages through its apo A-I, and more so, via its PON1, results in the attenuation of HDL-PON1 biological activities. In conclusion, PON1 specifically binds to macrophage binding sites, leading to anti-atherogenic effects. Macrophage PON1 binding sites may thus be a target for future cardio protection therapy.
ESTHER : Efrat_2008_Biochem.Biophys.Res.Commun_376_105
PubMedSearch : Efrat_2008_Biochem.Biophys.Res.Commun_376_105
PubMedID: 18762170

Title : Consumption of wonderful variety pomegranate juice and extract by diabetic patients increases paraoxonase 1 association with high-density lipoprotein and stimulates its catalytic activities - Rock_2008_J.Agric.Food.Chem_56_8704
Author(s) : Rock W , Rosenblat M , Miller-Lotan R , Levy AP , Elias M , Aviram M
Ref : Journal of Agricultural and Food Chemistry , 56 :8704 , 2008
Abstract : Association of paraoxonase 1 (PON1) with high-density lipoprotein (HDL) stabilizes the enzyme. In diabetic patients, PON1 dissociates from HDL and, as a consequence, is less biologically active. Our aim was to investigate the effects of Wonderful variety pomegranate juice (WPJ) and pomegranate polyphenol extract (WPOMxl) consumption on PON1 association with HDL in diabetic patients. Thirty patients with type 2 diabetes mellitus participated in the study. Ten male patients and 10 female patients received concentrated WPJ (50 mL/day for 4 weeks), while another group of 10 male patients received WPOMxl (5 mL/day for 6 weeks). There were no significant effects of WPJ or WPOMxl consumption on fasting blood glucose or hemoglobin A1c levels. After 4 weeks of WPJ consumption by male patients, basal serum oxidative stress was significantly decreased by 35%, whereas serum concentrations of thiol groups significantly increased by 25%. Moreover, HDL-associated PON1 arylesterase, paraoxonase, and lactonase activities increased significantly after WPJ consumption by 34-45%, as compared to the baseline levels. PON1 protein binding to HDL was significantly increased by 30% following WPJ consumption, and the enzyme became more stable. In male patients that consumed WPOMxl and in female patients that consumed PJ, a similar pattern was observed, although to a lesser extent. We conclude that WPJ as well as WPOMxl consumption by diabetic patients does not worsen their diabetic parameters. Furthermore, WPJ as well as WPOMxl consumption contribute to PON1 stabilization, increased association with HDL, and enhanced catalytic activities. These beneficial effects of pomegranate consumption on serum PON1 stability and activity could lead to retardation of atherosclerosis development in diabetic patients.
ESTHER : Rock_2008_J.Agric.Food.Chem_56_8704
PubMedSearch : Rock_2008_J.Agric.Food.Chem_56_8704
PubMedID: 18759451

Title : Urokinase plasminogen activator upregulates paraoxonase 2 expression in macrophages via an NADPH oxidase-dependent mechanism - Fuhrman_2008_Arterioscler.Thromb.Vasc.Biol_28_1361
Author(s) : Fuhrman B , Khateeb J , Shiner M , Nitzan O , Karry R , Volkova N , Aviram M
Ref : Arterioscler Thromb Vasc Biol , 28 :1361 , 2008
Abstract : OBJECTIVE: Macrophage foam cells are characterized by increased oxidative stress. Macrophage urokinase plasminogen activator (uPA) was shown to contribute to atherosclerosis progression. We hypothesized that uPA atherogenicity is related to its ability to increase macrophage oxidative stress. Increased macrophage oxidative stress in turn was shown to enhance PON2 expression. In the present study we investigated the effect of uPA on macrophage PON2 expression in relation to cellular oxidative stress. METHODS AND
RESULTS: uPA increased PON2 expression in THP-1 macrophages in a dose-dependent manner. This effect required uPA/uPAR interaction and was abolished by cell treatment with antioxidants. uPA increased macrophage oxidative stress, measured by increased lipid peroxides, reactive oxygen species formation, superoxide anion release, and cell-mediated LDL oxidation. These effects were related to uPA-mediated activation of NADPH oxidase, and could not be reproduced in mouse peritoneal macrophages (MPM) harvested from p47(phox)-/- mice, suggesting a causal relationship between NADPH oxidase activation and the effects of uPA on macrophage oxidative stress and PON2 expression. Finally, MPM from PON2(-/-) mice were more susceptible to uPA-induced cellular oxidative stress than wild-type MPM, suggesting that PON2 protects against uPA-stimulated macrophage oxidative stress.
CONCLUSIONS: Upregulation of macrophage PON2 may provide a compensatory protective mechanism against uPA-stimulation of macrophage oxidative stress during atherogenesis.
ESTHER : Fuhrman_2008_Arterioscler.Thromb.Vasc.Biol_28_1361
PubMedSearch : Fuhrman_2008_Arterioscler.Thromb.Vasc.Biol_28_1361
PubMedID: 18436804

Title : Paraoxonases (PON1, PON2, PON3) analyses in vitro and in vivo in relation to cardiovascular diseases - Aviram_2008_Methods.Mol.Biol_477_259
Author(s) : Aviram M , Rosenblat M
Ref : Methods Mol Biol , 477 :259 , 2008
Abstract : Mammalian paraoxonases (PON1, PON2, PON3) are a unique family of calcium-dependent hydrolases, with enzymatic activities toward a broad range of substrates (lactones, thiolactones, carbonates, esters, phosphotriesters). Although PONs physiological substrates were not yet identified, some studies suggest that they could be some lactones, or some specific oxidized phospholipids, or products of both enzymatic and nonenzymatic oxidation of arachidonic and docosahexaenoic acid, as well as N-acyl-homoserine lactones (which are quorum-sensing signals of pathogenic bacteria). Since no endogenous substrates for PONs activity determination are available yet, synthetic substrates such as paraoxon, phenyl acetate, and several lactones are used for PONs activity assays. All three members of the PON family (PON 1/2/3) were shown to protect from atherosclerosis development. Their anti-atherogenic biological activities were studied in vitro using serum or cell cultures, and also in vivo, using PON 1/2/3 knockout or transgenic mice, as well as humans - healthy volunteers and atherosclerotic patients (diabetics, hypercholesterolemics, and hypertensives).
ESTHER : Aviram_2008_Methods.Mol.Biol_477_259
PubMedSearch : Aviram_2008_Methods.Mol.Biol_477_259
PubMedID: 19082953

Title : Pomegranate phenolics from the peels, arils, and flowers are antiatherogenic: studies in vivo in atherosclerotic apolipoprotein e-deficient (E 0) mice and in vitro in cultured macrophages and lipoproteins - Aviram_2008_J.Agric.Food.Chem_56_1148
Author(s) : Aviram M , Volkova N , Coleman R , Dreher M , Reddy MK , Ferreira D , Rosenblat M
Ref : Journal of Agricultural and Food Chemistry , 56 :1148 , 2008
Abstract : We have analyzed in vivo and in vitro the antiatherogenic properties and mechanisms of action of all pomegranate fruit parts: peels (POMxl, POMxp), arils (POMa), seeds (POMo), and flowers (POMf), in comparison to whole fruit juice (PJ). Atherosclerotic E 0 mice consumed POM extracts [200 microg of gallic acid equivalents (GAE)/mouse/day] for 3 months. Blood samples, peritoneal macrophages (MPM), and aortas were then collected. All POM extracts possess antioxidative properties in vitro. After consumption of PJ, POMxl, POMxp, POMa, or POMf by E (0) mice, the atherosclerotic lesion area was significantly decreased by 44, 38, 39, 6, or 70%, respectively, as compared to placebo-treated group, while POMo had no effect. POMf consumption reduced serum lipids, and glucose levels by 18-25%. PJ, POMxl, POMxp, POMf, or POMa consumption resulted in a significant decrement, by 53, 42, 35, 27, or 13%, respectively, in MPM total peroxides content, and increased cellular paraoxonase 2 (PON2) activity, as compared to placebo-treated mice. The uptake rates of oxidized-LDL by E (0)-MPM were significantly reduced by approximately 15% after consumption of PJ, POMxl, or POMxp. Similar results were obtained on using J774A.1 macrophage cell line. Finally, pomegranate phenolics (punicalagin, punicalin, gallic acid, and ellagic acid), as well as pomegranate unique complexed sugars, could mimic the antiatherogenic effects of pomegranate extracts. We conclude that attenuation of atherosclerosis development by some of the POM extracts and, in particular, POMf, could be related to the combined beneficial effects on serum lipids levels and on macrophage atherogenic properties.
ESTHER : Aviram_2008_J.Agric.Food.Chem_56_1148
PubMedSearch : Aviram_2008_J.Agric.Food.Chem_56_1148
PubMedID: 18173244

Title : Antiatherogenicity of extra virgin olive oil and its enrichment with green tea polyphenols in the atherosclerotic apolipoprotein-E-deficient mice: enhanced macrophage cholesterol efflux - Rosenblat_2008_J.Nutr.Biochem_19_514
Author(s) : Rosenblat M , Volkova N , Coleman R , Almagor Y , Aviram M
Ref : J Nutr Biochem , 19 :514 , 2008
Abstract : The antiatherogenic properties of extra virgin olive oil (EVOO) enriched with green tea polyphenols (GTPPs; hereafter called EVOO-GTPP), in comparison to EVOO, were studied in the atherosclerotic apolipoprotein-E-deficient (E0) mice. E0 mice (eight mice in each group) consumed EVOO or EVOO-GTPP (7 microl/mouse/day, for 2 months) by gavage feeding. The placebo group received only water. At the end of the study, blood samples, peritoneal macrophages and aortas were collected. Consumption of EVOO or EVOO-GTPP resulted in a minimal increase in serum total and high-density lipoprotein (HDL) cholesterol levels (by 12%) and in serum paraoxonase 1 activity (by 6% and 10%). EVOO-GTPP (but not EVOO) decreased the susceptibility of the mouse serum to AAPH-induced lipid peroxidation (by 18%), as compared to the placebo-treated mice. The major effect of both EVOO and EVOO-GTPP consumption was on HDL-mediated macrophage cholesterol efflux. Consumption of EVOO stimulated cholesterol efflux rate from mouse peritoneal macrophages (MPMs) by 42%, while EVOO-GTPP increased it by as much as 139%, as compared to MPMs from placebo-treated mice. Finally, the atherosclerotic lesion size of mice was significantly reduced by 11% or 20%, after consumption of EVOO or EVOO-GTPP, respectively. We thus conclude that EVOO possesses beneficial antiatherogenic effects, and its enrichment with GTPPs further improved these effects, leading to the attenuation of atherosclerosis development.
ESTHER : Rosenblat_2008_J.Nutr.Biochem_19_514
PubMedSearch : Rosenblat_2008_J.Nutr.Biochem_19_514
PubMedID: 17904345

Title : Paraoxonase 1 (PON1) attenuates diabetes development in mice through its antioxidative properties - Rozenberg_2008_Free.Radic.Biol.Med_44_1951
Author(s) : Rozenberg O , Shiner M , Aviram M , Hayek T
Ref : Free Radic Biol Med , 44 :1951 , 2008
Abstract : Paraoxonase 1 (PON1) is a lipo-lactonase which is associated with HDL and possesses antioxidative properties. Diabetes is characterized by increased oxidative stress and by decreased PON1 activity. We aimed to analyze whether oxidative status and PON1 levels in mouse sera and macrophages could affect streptozotocin (STZ)-induced diabetes development. We have used two models of mice under low oxidative stress: STZ-injected apolipoprotein E-deficient mice supplemented with the antioxidant vitamin E, and P47(phox) knockout mice. In both mice models the decreased serum basal oxidative stress, was associated with a decreased rate of diabetes development, compared with control STZ-injected apolipoprotein E-deficient mice or with C57BL mice respectively. These data suggest that oxidative stress accelerates diabetes development. Next, we analyzed the effect of PON1 on macrophage oxidative stress and on diabetes development in STZ-injected C57BL mice, PON1 knockout mice, and PON1 transgenic mice. PON1 overexpression was associated with decreased diabetes-induced macrophage oxidative stress, decreased diabetes development, and decreased mortality, in comparison to C57BL mice, and even more so when compared to PON1KO mice. We thus concluded that on increasing PON1 expression in mice, diabetes development is attenuated, a phenomenon which could be attributed to the antioxidative properties of PON1, as decrement of oxidative stress significantly attenuated STZ-induced diabetes development.
ESTHER : Rozenberg_2008_Free.Radic.Biol.Med_44_1951
PubMedSearch : Rozenberg_2008_Free.Radic.Biol.Med_44_1951
PubMedID: 18358245

Title : Consumption of a novel dietary formula of plant sterol esters of canola oil fatty acids, in a canola oil matrix containing 1,3-diacylglycerol, reduces oxidative stress in atherosclerotic apolipoprotein E-deficient mice - Fuhrman_2007_J.Agric.Food.Chem_55_2028
Author(s) : Fuhrman B , Plat D , Herzog Y , Aviram M
Ref : Journal of Agricultural and Food Chemistry , 55 :2028 , 2007
Abstract : The antiatherogenic properties of a novel dietary formula (PS-CO) of plant sterol esters of fatty acids, produced by enzymatic interesterification of plant sterols with canola oil (CO), in a CO matrix containing 1,3-diacylglycerol, were evaluated in apolipoprotein E-deficient mice. PS-CO consumption strongly tended to lower total plasma cholesterol levels by 21%, compared to the placebo group. Blood triglycerides were reduced by 38% and 36% compared to CO and placebo-fed mice, respectively. Serum lipid peroxide levels were lowered following PS-CO administration by 62% and 63%, compared to CO and placebo administration, respectively. Unlike CO supplementation, PS-CO consumption preserved serum paraoxonase (PON1) activity. Mouse peritoneal macrophages from PS-CO-fed mice exhibited reduced cellular uptake of oxidized-LDL compared to those from placebo-fed mice and demonstrated a tendency toward a decreased capability to release superoxide anions. These findings indicate that PS-CO supplementation is beneficial in reducing serum lipid levels, and serum and macrophage oxidative stress, thus contributing to the reduction in atherogenic risk factors.
ESTHER : Fuhrman_2007_J.Agric.Food.Chem_55_2028
PubMedSearch : Fuhrman_2007_J.Agric.Food.Chem_55_2028
PubMedID: 17284051

Title : Anti-oxidant and anti-atherogenic properties of liposomal glutathione: studies in vitro, and in the atherosclerotic apolipoprotein E-deficient mice - Rosenblat_2007_Atherosclerosis_195_e61
Author(s) : Rosenblat M , Volkova N , Coleman R , Aviram M
Ref : Atherosclerosis , 195 :e61 , 2007
Abstract : Liposomal glutathione, but not the control liposomes (with no glutathione), dose-dependently inhibited copper ion-induced low density lipoprotein (LDL) and HDL oxidation. As peroxidase activity was found to be present in both LDL and HDL, it has contributed to the anti-oxidative effects of liposomal glutathione. In-vitro, no significant effect of liposomal glutathione on J774 A.1 macrophage cell-line oxidative stress and on cellular cholesterol metabolism was observed. In contrast, in the atherosclerotic apolipoprotein E-deficient (E(0)) mice, consumption of liposomal glutathione (12.5 or 50mg/kg/day, for 2 months), but not control liposomes, resulted in a significant reduction in the serum susceptibility to AAPH-induced oxidation by 33%. Liposomal glutathione (50mg/kg/day) consumption also resulted in an increment (by 12%) in the mice peritoneal macrophages (MPM) glutathione content, paralleled by a significant reduction in total cellular lipid peroxides content (by 40%), compared to placebo-treated mice MPM. MPM paraoxonase 2 activity was significantly increased by 27% and by 121%, after liposomal glutathione consumption (12.5 or 50mg/kg/day, respectively). Analyses of cellular cholesterol fluxes revealed that, liposomal glutathione (12.5mg/kg/day) consumption, decreased the extent of oxidized-LDL (Ox-LDL) uptake by 17% and the cellular cholesterol biosynthesis rate, by 34%, and stimulated HDL-induced macrophage cholesterol efflux, by 19%. Most important, a significant reduction in macrophage cholesterol mass (by 24%), and in the atherosclerotic lesion area (by 30%) was noted. We thus conclude that liposomal glutathione possesses anti-oxidative and anti-atherogenic properties towards lipoproteins and macrophages, leading to attenuation of atherosclerosis development.
ESTHER : Rosenblat_2007_Atherosclerosis_195_e61
PubMedSearch : Rosenblat_2007_Atherosclerosis_195_e61
PubMedID: 17588583

Title : Macrophage NADPH oxidase activation, impaired cholesterol fluxes, and increased cholesterol biosynthesis in diabetic mice: a stimulatory role for D-glucose - Hayek_2007_Atherosclerosis_195_277
Author(s) : Hayek T , Kaplan M , Kerry R , Aviram M
Ref : Atherosclerosis , 195 :277 , 2007
Abstract : Diabetes is clearly associated with accelerated atherosclerosis development, but molecular mechanisms involved in diabetes-induced atherosclerosis remain to be clarified. The aim of this study was to identify cellular mechanisms involved in diabetes-induced macrophage foam cell formation, the hallmark of early atherogenesis. Mouse peritoneal macrophages (MPMs) isolated from Balb-C streptozotocin-induced diabetic mice, exhibited significantly higher total peroxides, lipid peroxides and paraoxonase 2 (PON2) activity by 290%, 61% and 55%, respectively, compared to non-diabetic mice. In vitro studies revealed that glucose-induced oxidative stress was obtained by D-glucose, but not by L-glucose and it involved activation of the NADPH oxidase complex, and up-regulation of the macrophage PON2. Next, MPMs isolated from Balb-C diabetic mice, compared to control Balb-C mice, demonstrated increased cholesterol content by 4.2-fold associated with increased cholesterol biosynthesis and increased uptake of oxidized LDL (Ox-LDL) by 5.9-fold and 31%, respectively. These effects on cellular cholesterol metabolism were associated with up-regulation of the scavenger receptors for Ox-LDL (CD-36 and SR-A), and of HMG-CoA reductase (cholesterol biosynthesis rate limiting enzyme). Finally, using pravastatin (inhibitor of HMG-CoA reductase) and the antioxidant Vitamin E, we have shown that D-glucose-induced macrophage oxidative stress is secondary to its stimulatory effect on macrophage cholesterol biosynthesis. In conclusion, macrophages from diabetic mice demonstrate increased oxidative stress associated with activation of NADPH oxidase and up-regulation of cellular PON2, as well as increased macrophages cholesterol uptake and biosynthesis (increased expression of CD-36 and HMG-CoA reductase). The above mechanisms in diabetic mice could be the result of the effect of high D-glucose on macrophages.
ESTHER : Hayek_2007_Atherosclerosis_195_277
PubMedSearch : Hayek_2007_Atherosclerosis_195_277
PubMedID: 17258748

Title : Macrophage paraoxonase 2 (PON2) expression is up-regulated by pomegranate juice phenolic anti-oxidants via PPAR gamma and AP-1 pathway activation - Shiner_2007_Atherosclerosis_195_313
Author(s) : Shiner M , Fuhrman B , Aviram M
Ref : Atherosclerosis , 195 :313 , 2007
Abstract : Paraoxonase 2 (PON2), a member of the paraoxonase gene family, was shown to protect macrophages against oxidative stress. Pomegranate juice (PJ), which contains potent polyphenol anti-oxidants, exhibits similar effects. We questioned possible association between PJ polyphenolics, macrophage oxidative stress, and cellular PON2 expression, in relation to the activation of specific PON2 transcription factors. Incubation of J774A.1 macrophages with PJ (0-50 microM of total polyphenols) dose-dependently increased expression (mRNA, protein) and activity and reduced macrophage oxidative status. These effects could be attributed to the PJ unique polyphenols, punicalagin and gallic acid. PJ polyphenol-induced up-regulation of PON2 was inhibited by 40% upon using the PPAR gamma inhibitor GW9662 (50 microM). Accordingly, the PPAR gamma ligand, rosiglitazone, dose-dependently stimulated macrophage PON2 expression, by up to 80%. Inhibition of AP-1 activation with SP600125, attenuated PJ-induced up-regulation of PON2 by 40%. Similarly, incubation of macrophages with PJ polyphenols in the presence of GW9662 or SP600125, significantly reduced their capacity to protect the cells against oxidative stress. We conclude that the anti-oxidative characteristics of PJ unique phenolics punicalagin and gallic acid could be related, at least in part, to their stimulatory effect on macrophage PON2 expression, a phenomenon which was shown to be associated with activation of the transcription factors PAPR gamma and AP-1.
ESTHER : Shiner_2007_Atherosclerosis_195_313
PubMedSearch : Shiner_2007_Atherosclerosis_195_313
PubMedID: 17292903

Title : Macrophage paraoxonase 2 (PON2) expression is upregulated by unesterified cholesterol through activation of the phosphatidylinositol 3-kinase (PI3K) pathway - Shiner_2007_Biol.Chem_388_1353
Author(s) : Shiner M , Fuhrman B , Aviram M
Ref : Biol Chem , 388 :1353 , 2007
Abstract : Advanced atherosclerotic lesions are characterized by a progressive increase in the unesterified cholesterol (UC) content and a decrease in its cholesteryl ester (CE) content. In the present study, we examined mechanisms involved in the effect of UC and CE on the expression of paraoxonase 2 (PON2) in macrophages. J774A.1 macrophages were enriched with CE or UC by incubation for 14-48 h with 50 microg acetylated low-density lipoprotein in the absence or presence of the acyl-CoA:cholesterol acyltransferase (ACAT) inhibitor 58035 (50 microg/ml), respectively. Macrophage PON2 mRNA expression, protein abundance and activity were increased only in the UC-enriched cells. In UC-enriched cells, inhibition of phosphatidylinositol 3-kinase (PI(3)K; using wortmannin or LY294002) attenuated the increase in PON2 mRNA expression by 50%, compared to untreated cells. In addition, we evidenced an increased phosphorylation of Akt in UC-enriched cells. Thus, we conclude from our data that macrophage PON2 expression is upregulated in UC-enriched macrophages through activation of the PI(3)K signal pathway.
ESTHER : Shiner_2007_Biol.Chem_388_1353
PubMedSearch : Shiner_2007_Biol.Chem_388_1353
PubMedID: 18020951

Title : HDL--associated paraoxonase 1 (PON1) and dietary antioxidants attenuate lipoprotein oxidation, macrophage foam cells formation and atherosclerosis development -
Author(s) : Aviram M
Ref : Pathophysiol Haemost Thromb , 35 :146 , 2006
PubMedID: 16855361

Title : Postprandial serum triacylglycerols and oxidative stress in mice after consumption of fish oil, soy oil or olive oil: possible role for paraoxonase-1 triacylglycerol lipase-like activity - Fuhrman_2006_Nutrition_22_922
Author(s) : Fuhrman B , Volkova N , Aviram M
Ref : Nutrition , 22 :922 , 2006
Abstract : OBJECTIVE: Postprandial triacylglycerols and oxidative stress responses are influenced by the type of fat consumed. We investigated the effect of individual unsaturated fatty acids or oils (fish, soy, or olive) on postprandial triglyceridemia response in association with serum resistance to oxidation and paraoxonase-1 (PON1) activity.
METHODS: Balb/C mice were supplemented with phosphate buffered saline (control), docosahexaenoic acid (omega-3), linoleic acid (omega-6), or oleic acid (omega-9; 500 microg/300 microL of phosphate buffered saline) and with fish, soy, or olive oil (300 microL); blood samples were collected 2 h after feeding.
RESULTS: Serum triacylglycerol and oxidative stress responses increased after intake of all unsaturated fatty acids and oil supplements. However, ingestion of fish oil or its major fatty acid, docosahexaenoic acid, induced the most remarkable increase in postprandial serum triacylglycerols and in the susceptibility of serum to in vitro oxidation. Serum PON1 activity was decreased by 24% after fish oil ingestion. The increase in postprandial serum susceptibility to oxidation was lower after soy oil supplementation to PON1-transgenic mice in comparison with Balb/C mice, showing that PON1 attenuates the postprandial serum oxidative response. In parallel, in PON1-transgenic mice, a decreased postprandial triacylglycerol response was noted, suggesting PON1 involvement in triacylglycerol metabolism. PON1 exhibited a triacylglycerol lipase-like activity on chylomicrons. CONCLUSION: PON1 attenuates the postprandial oxidative stress response, and this could have resulted from PON1 lipase-like activity on chylomicron triacylglycerols.
ESTHER : Fuhrman_2006_Nutrition_22_922
PubMedSearch : Fuhrman_2006_Nutrition_22_922
PubMedID: 16814984

Title : The catalytic histidine dyad of high density lipoprotein-associated serum paraoxonase-1 (PON1) is essential for PON1-mediated inhibition of low density lipoprotein oxidation and stimulation of macrophage cholesterol efflux - Rosenblat_2006_J.Biol.Chem_281_7657
Author(s) : Rosenblat M , Gaidukov L , Khersonsky O , Vaya J , Oren R , Tawfik DS , Aviram M
Ref : Journal of Biological Chemistry , 281 :7657 , 2006
Abstract : High density lipoprotein (HDL)-associated paraoxonase-1 (PON1) anti-atherogenic properties in macrophages, i.e. inhibition of cell-mediated oxidation of low density lipoprotein (LDL) and stimulation of cholesterol efflux, were studied using recombinant variants of PON1 and apoA-I expressed in Escherichia coli and reconstituted HDL (rHDL) particles composed of phosphatidylcholine/free cholesterol (PC/FC) and apoA-I. PON1 lactonase activity is stimulated by apoA-I by approximately 7-fold relative to PC/FC particles. Wild-type (WT) PON1 bound to rHDL inhibited macrophage-mediated LDL oxidation and stimulated cholesterol efflux from the cells to 2.3- and 3.2-fold greater extents, respectively, compared with WT PON1 bound to PC/FC particles without apoA-I. We also tested PON1 catalytic histidine dyad mutants (H115Q and H134Q) that are properly folded and that bind HDL in a similar mode compared with WT PON1, but that exhibit almost no lactonase activity. These could not inhibit macrophage-mediated LDL oxidation or stimulate rHDL-mediated cholesterol efflux from the cells. Furthermore, whereas HDL-bound WT PON1 induced the formation of lysophosphatidylcholine (LPC) in macrophages, the His dyad mutants did not, suggesting that the above anti-atherogenic properties of HDL-associated PON1 involve LPC release. Indeed, enrichment of macrophages with increasing concentrations of LPC resulted in inhibition of the cells' capability to oxidize LDL and in stimulation of HDL-mediated cholesterol efflux from the macrophages in an LPC dose-dependent manner. Thus, we provide the first direct indication that the anti-atherogenic properties of PON1 are related to its lipolactonase activity and propose a model in which PON1 acts as a lipolactonase to break down oxidized lipids and to generate LPC.
ESTHER : Rosenblat_2006_J.Biol.Chem_281_7657
PubMedSearch : Rosenblat_2006_J.Biol.Chem_281_7657
PubMedID: 16407304

Title : The 192R\/Q polymorphs of serum paraoxonase PON1 differ in HDL binding, lipolactonase stimulation, and cholesterol efflux - Gaidukov_2006_J.Lipid.Res_47_2492
Author(s) : Gaidukov L , Rosenblat M , Aviram M , Tawfik DS
Ref : J Lipid Res , 47 :2492 , 2006
Abstract : Serum paraoxonase (PON1) is a HDL-associated enzyme exhibiting potentially antiatherogenic properties. Here, we examined the common PON1-192R/Q human polymorphism. Despite numerous studies, the effect of this polymorphism on the antiatherogenic potential of PON1 is yet unresolved. Our structural model suggests that amino acid 192 constitutes part of the HDL-anchoring surface and active site of PON1. Based on our findings that PON1 is an interfacially activated lipolactonase that selectively binds HDL carrying apolipoprotein A-I (apoA-I) and is thereby greatly stabilized and catalytically activated, we examined the interaction of the PON1-192 isozymes with reconstituted HDL-apoA-I particles. We found that PON1 position 192 is indeed involved in HDL binding. The PON1-192Q binds HDL with a 3-fold lower affinity than the R isozyme and consequently exhibits significantly reduced stability, lipolactonase activity, and macrophage cholesterol efflux. We also observed the lower affinity and stability of the 192Q versus the 192R isozyme in sera of individuals belonging to the corresponding genotypes. The observed differences in the properties of PON1-192R/Q isozymes provide a basis for further analysis of the contribution of the 192R/Q polymorphism to the susceptibility to atherosclerosis, although other factors, such as the overall levels of PON1, may play a more significant role.
ESTHER : Gaidukov_2006_J.Lipid.Res_47_2492
PubMedSearch : Gaidukov_2006_J.Lipid.Res_47_2492
PubMedID: 16914770

Title : Anti-oxidative effects of pomegranate juice (PJ) consumption by diabetic patients on serum and on macrophages - Rosenblat_2006_Atherosclerosis_187_363
Author(s) : Rosenblat M , Hayek T , Aviram M
Ref : Atherosclerosis , 187 :363 , 2006
Abstract : Diabetes is associated with increased oxidative stress and atherosclerosis development. In the present study, we investigated the effects of pomegranate juice (PJ; which contains sugars and potent anti-oxidants) consumption by diabetic patients on blood diabetic parameters, and on oxidative stress in their serum and macrophages. Ten healthy subjects (controls) and 10 non-insulin dependent diabetes mellitus (NIDDM) patients who consumed PJ (50ml per day for 3 months) participated in the study. In the patients versus controls serum levels of lipid peroxides and thiobarbituric acid reactive substances (TBARS) were both increased, by 350% and 51%, respectively, whereas serum SH groups content and paraoxonase 1 (PON1) activity, were both decreased (by 23%). PJ consumption did not affect serum glucose, cholesterol and triglyceride levels, but it resulted in a significant reduction in serum lipid peroxides and TBARS levels by 56% and 28%, whereas serum SH groups and PON1 activity significantly increased by 12% and 24%, respectively. In the patients versus controls monocytes-derived macrophages (HMDM), we observed increased level of cellular peroxides (by 36%), and decreased glutathione content (by 64%). PJ consumption significantly reduced cellular peroxides (by 71%), and increased glutathione levels (by 141%) in the patients' HMDM. The patients' versus control HMDM took up oxidized LDL (Ox-LDL) at enhanced rate (by 37%) and PJ consumption significantly decreased the extent of Ox-LDL cellular uptake (by 39%). We thus conclude that PJ consumption by diabetic patients did not worsen the diabetic parameters, but rather resulted in anti-oxidative effects on serum and macrophages, which could contribute to attenuation of atherosclerosis development in these patients.
ESTHER : Rosenblat_2006_Atherosclerosis_187_363
PubMedSearch : Rosenblat_2006_Atherosclerosis_187_363
PubMedID: 16226266

Title : Paraoxonase 1 (PON1) is a more potent antioxidant and stimulant of macrophage cholesterol efflux, when present in HDL than in lipoprotein-deficient serum: relevance to diabetes - Rosenblat_2006_Atherosclerosis_187_74
Author(s) : Rosenblat M , Karry R , Aviram M
Ref : Atherosclerosis , 187 :74 , 2006
Abstract : The present study analyzed serum paraoxonase 1 (PON1) distribution among HDL and lipoprotein-deficient serum (LPDS) in atherosclerotic patients, and compared PON1 biological functions in these fractions. Serum HDL and LPDS fractions were isolated from control healthy subjects, diabetic and hypercholesterolemic patients. PON1 activities and protein in HDL/LPDS, as well as its ability to protect against lipid peroxidation and to stimulate HDL/LPDS-mediated macrophage cholesterol efflux were measured. In LPDS from controls, PON1 protein and a significant paraoxonase activity were found, whereas arylesterase and lactonase activities were substantially reduced compared to HDL, by 78% and 88%, respectively. In diabetic patients, PON1 protein and paraoxonase activity in HDL were significantly decreased by 2.8- and 1.7-fold, respectively, compared with controls' HDL. In parallel, in these patient's LPDS, PON1 protein and paraoxonase activity were markedly increased by 3.7- and 1.7-fold, respectively, compared with controls' LPDS. PON1 in HDL (but not PON1 in LPDS) significantly decreased AAPH-induced lipid peroxides formation by 33%, and increased macrophage cholesterol efflux by 31%. We conclude that PON1 is less antiatherogenic when present in LPDS than in HDL. The abnormal serum PON1 distribution in diabetic patients, could be responsible for the accelerated atherosclerosis development in these patients.
ESTHER : Rosenblat_2006_Atherosclerosis_187_74
PubMedSearch : Rosenblat_2006_Atherosclerosis_187_74
PubMedID: 16229851

Title : Lysophosphatidylcholine (LPC) attenuates macrophage-mediated oxidation of LDL - Rosenblat_2006_Biochem.Biophys.Res.Commun_344_1271
Author(s) : Rosenblat M , Oren R , Aviram M
Ref : Biochemical & Biophysical Research Communications , 344 :1271 , 2006
Abstract : We have previously shown that paraoxonase 1 action on macrophages produced lysophosphatidylcholine (LPC) and significantly decreased cell-mediated LDL oxidation. Thus, in the present study, we questioned whether LPC can directly inhibit macrophage-mediated oxidation of LDL. Addition of increasing LPC concentrations (0-5 microM) to J774A.1 macrophages, mouse peritoneal macrophages (MPM), or to human monocytes-derived macrophages (HMDM) resulted in up to 83%, 67%, and 75% inhibition in cell-mediated oxidation of LDL, respectively. The mechanism for this LPC effect involves up to 60% inhibition of superoxide anion release from MPM in response to phorbol ester (PMA), 26% inhibition of PMA-induced NADPH oxidase activation (p47phox translocation from the cytosol to the plasma membrane), and a 2-fold stimulation of the macrophage paraoxonase 2 (PON2) lactonase activity. We thus conclude that inhibition of macrophage-mediated oxidation of LDL by LPC can contribute to attenuation of macrophage foam cell formation and atherosclerotic lesion development.
ESTHER : Rosenblat_2006_Biochem.Biophys.Res.Commun_344_1271
PubMedSearch : Rosenblat_2006_Biochem.Biophys.Res.Commun_344_1271
PubMedID: 16650824

Title : Pomegranate byproduct administration to apolipoprotein e-deficient mice attenuates atherosclerosis development as a result of decreased macrophage oxidative stress and reduced cellular uptake of oxidized low-density lipoprotein - Rosenblat_2006_J.Agric.Food.Chem_54_1928
Author(s) : Rosenblat M , Volkova N , Coleman R , Aviram M
Ref : Journal of Agricultural and Food Chemistry , 54 :1928 , 2006
Abstract : The effects of a pomegranate byproduct (PBP, which includes the whole pomegranate fruit left after juice preparation) on atherosclerosis development in apolipoprotein E-deficient (E degrees ) mice were studied. Consumption of PBP (17 or 51.5 microg of gallic acid equiv/kg/day) by the mice resulted in a significant reduction in atherosclerotic lesion size by up to 57%. PBP consumption significantly reduced oxidative stress in the mice peritoneal macrophages (MPM): Cellular lipid peroxide content decreased by up to 42%, the reduced glutathione levels increased by up to 53%, and paraoxonase 2 lactonase activity increased by up to 50%, as compared to MPM from E degrees mice that consumed only water. Furthermore, oxidized low-density lipoprotein (Ox-LDL) uptake by the MPM was reduced by up to 19%. Similar results were observed also in vitro. Treatment of J774A.1 macrophages with PBP (10 or 50 micromol/L of total polyphenols) significantly decreased both cellular total peroxide content and Ox-LDL uptake. It was thus concluded that PBP significantly attenuates atherosclerosis development by its antioxidant properties.
ESTHER : Rosenblat_2006_J.Agric.Food.Chem_54_1928
PubMedSearch : Rosenblat_2006_J.Agric.Food.Chem_54_1928
PubMedID: 16506855

Title : Effect of a Mediterranean meal on postprandial carotenoids, paraoxonase activity and C-reactive protein levels - Blum_2006_Ann.Nutr.Metab_50_20
Author(s) : Blum S , Aviram M , Ben-Amotz A , Levy Y
Ref : Ann Nutr Metab , 50 :20 , 2006
Abstract : BACKGROUND AND AIM: Atherosclerosis involves oxidative and inflammatory mediators regulated by fat and antioxidants. Therefore, we studied the postprandial evolution of plasma lipids, carotenoids, C-reactive protein (CRP), and human serum paraoxanase activity (PON1) following two different fatty meals. SUBJECTS AND
METHODS: Eight healthy males consumed a 45% fat 1,000 Kcal Mediterranean-like (Med) meal (monounsaturated 61% of fat) compared to a Western-like (Wes) (saturated 57% of fat) meal. Blood was collected at baseline (time 0) 2, 4 and 7 h postprandial. Plasma lipids, glucose, insulin, total carotenoids, CRP, and PON1 were analyzed.
RESULTS: There was a marginal increase in cholesterol and glucose after both meals. Triglycerides increased modestly (to less than 200 mg/dl) and insulin increased (more in the Wes-like meal) but still within normal range, indicating a low glycemic index for both meals. Only the Med-like meal resulted in a significant increase in both PON1 activity (16%, p < 0.02) and carotenoids (74%, p < 0.02) with a 2-hour postprandial decrease in CRP (6%, p < 0.02). CONCLUSION: A postprandial monounsaturated fatty acid rich meal increases both plasma carotenoids and PON1 with a decrease in CRP levels, thus providing a novel potential explanation to the protective properties of a Mediterranean diet against atherogenesis.
ESTHER : Blum_2006_Ann.Nutr.Metab_50_20
PubMedSearch : Blum_2006_Ann.Nutr.Metab_50_20
PubMedID: 16276071

Title : S-Glutathionylation regulates HDL-associated paraoxonase 1 (PON1) activity - Rozenberg_2006_Biochem.Biophys.Res.Commun_351_492
Author(s) : Rozenberg O , Aviram M
Ref : Biochemical & Biophysical Research Communications , 351 :492 , 2006
Abstract : HDL-associated paraoxonase 1 (PON1) undergoes inactivation under oxidative stress and is preserved by dietary antioxidants. PON1 cysteines can affect PON1 enzymatic activities. S-Glutathionylation, a redox regulatory mechanism characterized by the formation of a mixed disulfide between a protein thiol and oxidized glutathione (GSSG), was shown to preserve some enzymes from irreversible inactivation under pathological conditions. We questioned whether PON1 activity is regulated by S-glutathionylation. Incubation of PON1 or HDL with GSSG indeed resulted in a dose-dependent inactivation of PON1 activities, including its physiological activity to increase HDL-mediated macrophage cholesterol efflux. This PON1 inactivation was associated with the formation of a mixed disulfide bond between GSSG and PON1's cysteine residue(s), as detected by immunoblotting with anti-glutathione IgG. PON1 activity was recovered following the addition of a reducing agent, DL-Dithiothreitol (DTT), to the PON1-SSG complex. We thus conclude that HDL-associated serum PON1 can undergo S-glutathionylation under oxidative stress with a consequent reversible inactivation.
ESTHER : Rozenberg_2006_Biochem.Biophys.Res.Commun_351_492
PubMedSearch : Rozenberg_2006_Biochem.Biophys.Res.Commun_351_492
PubMedID: 17070779

Title : Pomegranate juice sugar fraction reduces macrophage oxidative state, whereas white grape juice sugar fraction increases it - Rozenberg_2006_Atherosclerosis_188_68
Author(s) : Rozenberg O , Howell A , Aviram M
Ref : Atherosclerosis , 188 :68 , 2006
Abstract : The antiatherogenic properties of pomegranate juice (PJ) were attributed to its antioxidant potency and to its capacity to decrease macrophage oxidative stress, the hallmark of early atherogeneis. PJ polyphenols and sugar-containing polyphenolic anthocyanins were shown to confer PJ its antioxidant capacity. In the present study, we questioned whether PJ simple or complex sugars contribute to the antioxidative properties of PJ in comparison to white grape juice (WGJ) sugars. Whole PJ decreased cellular peroxide levels in J774A.1 macrophage cell-line by 23% more than PJ polyphenol fraction alone. Thus, we next determined the contribution of the PJ sugar fraction to the decrease in macrophage oxidative state. Increasing concentrations of the PJ sugar fraction resulted in a dose-dependent decrement in macrophage peroxide levels, up to 72%, compared to control cells. On the contrary, incubation of the cells with WGJ sugar fraction at the same concentrations resulted in a dose-dependent increment in peroxide levels by up to 37%. The two sugar fractions from PJ and from WGJ showed opposite effects (antioxidant for PJ and pro-oxidant for WGJ) also in mouse peritoneal macrophages (MPM) from control as well as from streptozotocin-induced diabetic Balb/C mice. PJ sugar consumption by diabetic mice for 10 days resulted in a small but significant decrement in their peritoneal macrophage total peroxide levels and an increment in cellular glutathione content, compared to MPM harvested from control diabetic mice administrated with water. In contrast, WGJ sugar consumption by diabetic mice resulted in a 22% increment in macrophage total peroxide levels and a 45% decrement in cellular glutathione content. Paraoxonase 2 activity in macrophages increases under oxidative stress conditions. Indeed, macrophage paraoxonase 2 activity was decreased after PJ sugars supplementation, but increased after WGJ sugars supplementation. We conclude that PJ sugar fraction, unlike WGJ sugar fraction, decreases macrophage oxidative state under normal and under diabetic conditions. These antioxidant/antiatherogenic effects could be due to the presence of unique complex sugars and/or phenolic sugars in PJ.
ESTHER : Rozenberg_2006_Atherosclerosis_188_68
PubMedSearch : Rozenberg_2006_Atherosclerosis_188_68
PubMedID: 16332370

Title : A biphasic U-shape effect of cellular oxidative stress on the macrophage anti-oxidant paraoxonase 2 (PON2) enzymatic activity - Shiner_2006_Biochem.Biophys.Res.Commun_349_1094
Author(s) : Shiner M , Fuhrman B , Aviram M
Ref : Biochemical & Biophysical Research Communications , 349 :1094 , 2006
Abstract : Expression of macrophage paraoxonase 2 (PON2), a cellular lactonase with anti-oxidant and anti-atherogenic properties, was shown to be upregulated under high oxidative stress. The aim of the present study was to analyze the relationship between the extent of cellular oxidative stress in J774A.1 macrophage and PON2 lactonase activity under various levels of oxidation, obtained by cell incubation with either anti-oxidants or oxidants. PON2 activity exhibited a U-shape response curve. In the oxidative stress range below that of control untreated cells, PON2 activity decreased upon increasing macrophage oxidative state, whereas in the range over that of control untreated cells, PON2 activity increased. The biphasic effect of oxidative stress on macrophage PON2 activity could be related to PON2 inactivation (decreased enzymatic activity) under oxidative stress induction at its low range, whereas at high range of oxidative stress, macrophage anti-oxidant compensatory mechanism up-regulates PON2 (increased protein expression), in order to cope with oxidative burden.
ESTHER : Shiner_2006_Biochem.Biophys.Res.Commun_349_1094
PubMedSearch : Shiner_2006_Biochem.Biophys.Res.Commun_349_1094
PubMedID: 16970920

Title : Dietary antioxidants and paraoxonases against LDL oxidation and atherosclerosis development - Aviram_2005_Handb.Exp.Pharmacol_170_263
Author(s) : Aviram M , Kaplan M , Rosenblat M , Fuhrman B
Ref : Handbook of Experimental Pharmacology , 170 :263 , 2005
Abstract : Oxidative modification of low-density lipoprotein (LDL) in the arterial wall plays a key role in the pathogenesis of atherosclerosis. Under oxidative stress LDL is exposed to oxidative modifications by arterial wall cells including macrophages. Oxidative stress also induces cellular-lipid peroxidation, resulting in the formation of 'oxidized macrophages', which demonstrate increased capacity to oxidize LDL and increased uptake of oxidized LDL. Macrophage-mediated oxidation of LDL depends on the balance between pro-oxidants and antioxidants in the lipoprotein and in the cells. LDL is protected from oxidation by antioxidants, as well as by a second line of defense--paraoxonase 1 (PON1), which is a high-density lipoprotein-associated esterase that can hydrolyze and reduce lipid peroxides in lipoproteins and in arterial cells. Cellular paraoxonases (PON2 and PON3) may also play an important protective role against oxidative stress at the cellular level. Many epidemiological studies have indicated a protective role for a diet rich in fruits and vegetables against the development and progression of cardiovascular disease. A large number of studies provide data suggesting that consumption of dietary antioxidants is associated with reduced risk for cardiovascular diseases. Basic research provides plausible mechanisms by which dietary antioxidants might reduce the development of atherosclerosis. These mechanisms include inhibition of LDL oxidation, inhibition of cellular lipid peroxidation and consequently attenuation of cell-mediated oxidation of LDL. An additional possible mechanism is preservation/increment of paraoxonases activity by dietary antioxidants. This review chapter presents recent data on the anti-atherosclerotic effects and mechanism of action of three major groups of dietary antioxidants-vitamin E, carotenoids and polyphenolic flavonoids.
ESTHER : Aviram_2005_Handb.Exp.Pharmacol_170_263
PubMedSearch : Aviram_2005_Handb.Exp.Pharmacol_170_263
PubMedID: 16596803

Title : Paraoxonases and cardiovascular diseases: pharmacological and nutritional influences - Aviram_2005_Curr.Opin.Lipidol_16_393
Author(s) : Aviram M , Rosenblat M
Ref : Curr Opin Lipidol , 16 :393 , 2005
Abstract : PURPOSE OF REVIEW: To summarize the new articles published in the last year on paraoxonases, including their expression in cardiovascular diseases, and regulation by pharmacological and nutritional means. RECENT FINDINGS: The elucidation of the crystal structure of the paraoxonase 1 (PON1) gene, obtained by directed evolution, shows that it consists of a six-bladed beta-propeller with a unique active site. PON1 is present in HDL but also in lipoprotein-deficient serum, in VLDL and in chylomicrons. PON1 protects lipids in lipoproteins, in macrophages and in erythrocytes from oxidation. Cellular PON2 and PON3 were also shown to reduce oxidative stress. Beyond its antioxidative properties, PON1 possesses additional antiatherogenic properties against macrophage foam cell formation: attenuation of cholesterol and oxidized lipids influx, inhibition of macrophage cholesterol biosynthesis and stimulation of macrophage cholesterol efflux. The PON1 gene is regulated by Sp1 and protein kinase C, whereas the PON2 gene in macrophages is regulated by nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. PON1 activity and mass are both reduced in cardiovascular diseases and the hypocholesterolemic drugs, statins, increase serum PON1 activity (by reducing oxidative stress, or by upregulating hepatic PON1 expression). Expression of cellular PON2, like PON1, was upregulated by statins. Nutritional antioxidants, such as polyphenols, increase PON1 mRNA expression and activity, by an aryl hydrocarbon receptor-dependent mechanism. SUMMARY: The elucidation of PON1 structure and its active center has enabled a better understanding of its mechanism of action, including its physio-pathological substrate(s). Some drugs and nutrients including dietary antioxidants and polyphenols considerably increase the activities of paraoxonases which, in turn, can reduce oxidative stress and atherosclerosis development.
ESTHER : Aviram_2005_Curr.Opin.Lipidol_16_393
PubMedSearch : Aviram_2005_Curr.Opin.Lipidol_16_393
PubMedID: 15990587

Title : Paraoxonase 1 (PON1) is present in postprandial chylomicrons - Fuhrman_2005_Atherosclerosis_180_55
Author(s) : Fuhrman B , Volkova N , Aviram M
Ref : Atherosclerosis , 180 :55 , 2005
Abstract : Paraoxonase 1 (PON1) is an esterase, associated in serum with high density lipoprotein (HDL). As diet affects serum PON1 activity, we questioned whether PON1 is also carried by postprandial chylomicrons. Chylomicrons were isolated by ultracentrifugation from plasma of 10 healthy men, 3h after the consumption of a high fat, high carbohydrate meal, and were analyzed for the presence of PON1 arylesterase activity and protein. The present study shows for the first time that, in addition to the presence of PON1 mainly on HDL, postprandial chylomicrons also contain minor, but significant amount of PON1. PON1 was also present in chylomicrons derived from fasted patients with hyperchylomicronemia. In addition, PON1 was detected in very low density lipoprotein (VLDL), but not in LDL. The origin of chylomicron PON1 could be partly attributed to its transfer from HDL. Finally, this study demonstrates that postprandial chylomicrons inhibit copper ion-induced LDL oxidation, secondary to hydrolysis of lipid peroxides, a phenomenon which could be related, at least in part, to the chylomicron PON1 content. We conclude that postprandial chylomicrons contain PON1, which may function in the removal of atherogenic oxidized lipids.
ESTHER : Fuhrman_2005_Atherosclerosis_180_55
PubMedSearch : Fuhrman_2005_Atherosclerosis_180_55
PubMedID: 15823275

Title : Paraoxonase 1 (PON1) enhances HDL-mediated macrophage cholesterol efflux via the ABCA1 transporter in association with increased HDL binding to the cells: a possible role for lysophosphatidylcholine - Rosenblat_2005_Atherosclerosis_179_69
Author(s) : Rosenblat M , Vaya J , Shih DM , Aviram M
Ref : Atherosclerosis , 179 :69 , 2005
Abstract : We investigated the role of HDL-associated paraoxonase 1 (PON1) in HDL-mediated macrophage cholesterol efflux by using HDL derived from wild type mice (Control-HDL), from human PON1-transgenic mice (HDL-PON1Tg) or from PON1-knockout mice (HDL-PON1(0)). Cholesterol efflux from mouse peritoneal macrophages (MPM) or from J774 A.1 macrophage cell line by HDL-PON1Tg, was significantly increased (by 60%) compared to HDL-PON1(0). We demonstrated that this PON1 effect was associated with an increased HDL binding to the cells, as the binding of HDL-PON1Tg (or HDL-PON1(0) that was enriched with PON1) was increased by 50% compared to that of HDL-PON1(0). Using either a cAMP analogue, to increase ABCA1 receptor expression, or rabbit anti-mouse SR-BI specific antibody to block the SR-BI receptor, PON1 stimulation of HDL binding and of HDL-mediated macrophage cholesterol efflux, were both found to involve the ABCA1 transporter. Studies with PON1 specific inhibitors revealed that PON1 activity was required for its stimulation of HDL-mediated macrophage cholesterol efflux. Upon incubation of macrophages with Control-HDL or with HDL-PON1Tg, macrophage lysophosphatidylcholine (LPC) content was increased by 3.7- and 7.5-fold, respectively. Such an LPC enrichment of macrophages resulted in up to 60% increased HDL binding to the cells, and a 41% increased HDL-mediated cholesterol efflux. Similarly, macrophage loading with LPC (by either adding LPC, or PON1 or phospholipase A(2)) significantly increased apolipoprotein A-I (apoA-I) mediated cholesterol efflux by 104, 65 and 56%, respectively, in ABCA1 overexpressing macrophages. We conclude that HDL-associated PON1 may contribute to the attenuation of atherosclerosis development by its ability to act on macrophage phospholipids, to form LPC, in turn, stimulates HDL binding and HDL-mediated macrophage cholesterol efflux via the ABCA1 transporter.
ESTHER : Rosenblat_2005_Atherosclerosis_179_69
PubMedSearch : Rosenblat_2005_Atherosclerosis_179_69
PubMedID: 15721011

Title : Paraoxonase 1 (PON1) attenuates macrophage oxidative status: studies in PON1 transfected cells and in PON1 transgenic mice - Rozenberg_2005_Atherosclerosis_181_9
Author(s) : Rozenberg O , Shih DM , Aviram M
Ref : Atherosclerosis , 181 :9 , 2005
Abstract : OBJECTIVE: High density lipoprotein (HDL)-associated paraoxonase 1 (PON1), hydrolyzes oxidized lipids in oxidized low density lipoprotein (LDL) and thus protects against atherosclerosis development. Increased susceptibility to atherosclerosis observed in PON1 knockout (PON1(0)) mice was associated with increased LDL lipid peroxidation as well as increased macrophage oxidative stress. Thus, the aim of the present study is to characterize the direct effect of PON1 on oxidative status processes in macrophages. METHODS AND
RESULTS: We used in vitro and in vivo models of PON1 expression in macrophages, as PON1 is not synthesized by these cells. Peritoneal macrophages (MPM) harvested from PON1(0) mice were transfected with human (hPON1). These cells exhibited reduced total peroxide levels by 47% and decreased capacity to release superoxide anions by 69%, associated with a small but significant increment of the reduced form of glutathione (GSH), a major cellular anti-oxidant, compared to control cells. MPM were also harvested from PON1 transgenic (PON1Tg) mice. Unexpectedly, these cells expressed hPON1 (mRNA and activity). Compared to MPM derived from control C57BL/6J mice, PON1Tg mouse MPM exhibited 35% decreased cellular total peroxide levels, decreased capacity to produce superoxide anions and 47% decreased capacity to oxidize LDL. PON1Tg mouse MPM were also characterized by 51% increased levels of GSH, compared to control MPM. Similarly, MPM harvested from PON1Tg on the genetic background of the atherosclerotic apolipoprotein E knockout (PON1Tg/E(0)) mice also exhibited decreased oxidative stress, compared to E(0) mouse MPM. Aortas obtained from these mice were characterized by decreased lipid peroxide levels, decreased capacity to oxidize LDL, and also increased GSH levels, compared to aortas obtained from E(0) mice. The decreased macrophage and aortic oxidative stress in PON1Tg/E(0) mice was associated with 2.7-fold decreased atherosclerotic lesion size in comparison to E(0) mice.
CONCLUSIONS: PON1 directly reduced macrophage and aortic oxidative status, which was associated with decreased superoxide anion production and increased glutathione content. These phenomena could be responsible for the observed attenuated atherosclerosis development in PON1Tg mice in comparison to control mice.
ESTHER : Rozenberg_2005_Atherosclerosis_181_9
PubMedSearch : Rozenberg_2005_Atherosclerosis_181_9
PubMedID: 15939049

Title : Paraoxonases (PONs) 1, 2, and 3 are expressed in human and mouse gastrointestinal tract and in Caco-2 cell line: selective secretion of PON1 and PON2 - Shamir_2005_Free.Radic.Biol.Med_39_336
Author(s) : Shamir R , Hartman C , Karry R , Pavlotzky E , Eliakim R , Lachter J , Suissa A , Aviram M
Ref : Free Radic Biol Med , 39 :336 , 2005
Abstract : The paraoxonase (PON) family contains three genes (PON1/2/3) that are believed to be involved in the protection against oxidative stress. PON1 and PON3 are circulating in serum attached to high-density lipoprotein fraction (HDL), whereas PON2 is ubiquitously expressed. The intestine is the second major organ that synthesizes lipoproteins; therefore, we examined PON mRNA expression and protein levels in gastrointestinal biopsies from humans, from C57BL6 mice, and from Caco-2 cells, a colon carcinoma-derived cell line that exhibits properties of intestinal epithelium at differentiation. PON 1/2/3 mRNA and proteins were present in human biopsies with variable expression among different gastrointestinal segments. Only PON2 and PON3 were present in mice. All PON mRNA, proteins, and enzymatic activities were present in Caco-2 cells. Oxidation of CaCo-2 cells with ferrum ascorbate had no significant effect on PON mRNA expression, but it increased paraoxonase and lactonase activity, whereas statinase activity was decreased. We showed polarized secretion of PON1 (basolateral) and PON2 (apical) into Caco-2 culture medium, raising the possibility that intestine is capable of producing and releasing PON1 and PON3 to the circulation, whereas PON2 is released at the brush-border membrane to intestinal lumen where it may perform another yet unclear function.
ESTHER : Shamir_2005_Free.Radic.Biol.Med_39_336
PubMedSearch : Shamir_2005_Free.Radic.Biol.Med_39_336
PubMedID: 15993332

Title : Introduction to the serial review on paraoxonases, oxidative stress, and cardiovascular diseases -
Author(s) : Aviram M
Ref : Free Radic Biol Med , 37 :1301 , 2004
PubMedID: 15454270

Title : Acetylcholine esterase protects LDL against oxidation - Fuhrman_2004_Biochem.Biophys.Res.Commun_322_974
Author(s) : Fuhrman B , Partoush A , Aviram M
Ref : Biochemical & Biophysical Research Communications , 322 :974 , 2004
Abstract : Acetylcholine esterase (AChE) and paraoxonase 1 (PON1) are both serum ester hydrolases, which are associated with the prevalence of myocardial infarction. Both genes are located in close proximity on chromosome 7q21-22. As PON1 was suggested to protect against cardiovascular diseases secondary to its ability to break down oxidized lipids and to inhibit LDL oxidation, we examined AChE capacity to protect LDL against oxidation. Preincubation of LDL with AChE retarded the onset of copper ion-induced LDL oxidation in a concentration-dependent manner. AChE significantly reduced the formation of lipid peroxides and TBARS during the course of LDL oxidation, by up to 45%. This effect was associated with AChE-mediated hydrolysis of lipid peroxides, which accounts for the inhibition in the onset of LDL oxidation, the oxidative propagation phase, and aldehyde formation. We conclude that AChE, similar to PON1, can hydrolyze lipid peroxides and thus may prevent the accumulation of oxidized LDL and attenuate atherosclerosis development.
ESTHER : Fuhrman_2004_Biochem.Biophys.Res.Commun_322_974
PubMedSearch : Fuhrman_2004_Biochem.Biophys.Res.Commun_322_974
PubMedID: 15336559

Title : Paraoxonases 1, 2, and 3, oxidative stress, and macrophage foam cell formation during atherosclerosis development - Aviram_2004_Free.Radic.Biol.Med_37_1304
Author(s) : Aviram M , Rosenblat M
Ref : Free Radic Biol Med , 37 :1304 , 2004
Abstract : Paraoxonases PON1 and PON3, which are both associated in serum with HDL, protect the serum lipids from oxidation, probably as a result of their ability to hydrolyze specific oxidized lipids. The activity of HDL-associated PON1 seems to involve an activity (phospholipase A2-like activity, peroxidase-like activity, lactonase activity) which produces LPC. To study the possible role of PON1 in macrophage foam cell formation and atherogenesis we used macrophages from control mice, from PON1 knockout mice, and from PON1 transgenic mice. Furthermore, we analyzed PON1-treated macrophages and PON1-transfected cells to demonstrate the contribution of PON1 to the attenuation of macrophage cholesterol and oxidized lipid accumulation and foam cell formation. PON1 was shown to inhibit cholesterol influx [by reducing the formation of oxidized LDL (Ox-LDL), increasing the breakdown of specific oxidized lipids in Ox-LDL, and decreasing macrophage uptake of Ox-LDL]. PON1 also inhibits cholesterol biosynthesis and stimulates HDL-mediated cholesterol efflux from macrophages. PON2 and PON3 protect against oxidative stress, with PON2 acting mainly at the cellular level. Whereas serum PON1 and PON3 were inactivated under oxidative stress, macrophage PON2 expression and activity were increased under oxidative stress, probably as a compensatory mechanism against oxidative stress. Intervention to increase the paraoxonases (cellular and humoral) by dietary or pharmacological means can reduce macrophage foam cell formation and attenuate atherosclerosis development.
ESTHER : Aviram_2004_Free.Radic.Biol.Med_37_1304
PubMedSearch : Aviram_2004_Free.Radic.Biol.Med_37_1304
PubMedID: 15454271

Title : Pomegranate juice consumption for 3 years by patients with carotid artery stenosis reduces common carotid intima-media thickness, blood pressure and LDL oxidation - Aviram_2004_Clin.Nutr_23_423
Author(s) : Aviram M , Rosenblat M , Gaitini D , Nitecki S , Hoffman A , Dornfeld L , Volkova N , Presser D , Attias J , Liker H , Hayek T
Ref : Clin Nutr , 23 :423 , 2004
Abstract : Dietary supplementation with polyphenolic antioxidants to animals was shown to be associated with inhibition of LDL oxidation and macrophage foam cell formation, and attenuation of atherosclerosis development. We investigated the effects of pomegranate juice (PJ, which contains potent tannins and anthocyanins) consumption by atherosclerotic patients with carotid artery stenosis (CAS) on the progression of carotid lesions and changes in oxidative stress and blood pressure. Ten patients were supplemented with PJ for 1 year and five of them continued for up to 3 years. Blood samples were collected before treatment and during PJ consumption. In the control group that did not consume PJ, common carotid intima-media thickness (IMT) increased by 9% during 1 year, whereas, PJ consumption resulted in a significant IMT reduction, by up to 30%, after 1 year. The patients' serum paraoxonase 1 (PON 1) activity was increased by 83%, whereas serum LDL basal oxidative state and LDL susceptibility to copper ion-induced oxidation were both significantly reduced, by 90% and 59%, respectively, after 12 months of PJ consumption, compared to values obtained before PJ consumption. Furthermore, serum levels of antibodies against oxidized LDL were decreased by 19%, and in parallel serum total antioxidant status (TAS) was increased by 130% after 1 year of PJ consumption. Systolic blood pressure was reduced after 1 year of PJ consumption by 12% [corrected] and was not further reduced along 3 years of PJ consumption. For all studied parameters, the maximal effects were observed after 1 year of PJ consumption. Further consumption of PJ, for up to 3 years, had no additional beneficial effects on IMT and serum PON1 activity, whereas serum lipid peroxidation was further reduced by up to 16% after 3 years of PJ consumption. The results of the present study thus suggest that PJ consumption by patients with CAS decreases carotid IMT and systolic blood pressure and these effects could be related to the potent antioxidant characteristics of PJ polyphenols.
ESTHER : Aviram_2004_Clin.Nutr_23_423
PubMedSearch : Aviram_2004_Clin.Nutr_23_423
PubMedID: 15158307

Title : Decreased macrophage paraoxonase 2 expression in patients with hypercholesterolemia is the result of their increased cellular cholesterol content: effect of atorvastatin therapy - Rosenblat_2004_Arterioscler.Thromb.Vasc.Biol_24_175
Author(s) : Rosenblat M , Hayek T , Hussein K , Aviram M
Ref : Arterioscler Thromb Vasc Biol , 24 :175 , 2004
Abstract : OBJECTIVE: To analyze paraoxonase2 (PON2) expression in human monocyte-derived macrophages (HMDM) from patients with hypercholesterolemia in relation to cellular cholesterol and oxidative stress. METHODS AND
RESULTS: Ten healthy subjects (controls) and 10 patients with hypercholesterolema who received 20-mg/d atorvastatin participated in the study. The patients' versus controls' HMDM demonstrated increased cholesterol content (270%) and oxidative stress (30% to 45%). Atorvastatin therapy reduced these parameters (59% and 25%, respectively). The patients' versus controls' macrophage-PON2 mRNA expression and PON2 activity were lower (100% and 40%, respectively), and atorvastatin therapy increased these parameters (76% and 200%, respectively). Untreated patient HMDM incubation with atorvastatin (0 to 10 micromol/L) resulted in a dose-dependent reduction in cellular cholesterol content and in cell-mediated low-density lipoprotein (LDL) oxidation up to 79% and 66%, respectively. In parallel, PON2 mRNA expression and PON2 activity increased dose-dependently up to 3.6- and 2.1-fold, respectively. On incubation of control HMDM with acetylated-LDL or aggregated-LDL, cellular cholesterol content increased (77% and 100%), and macrophage-PON2 activity decreased (49% and 22%), respectively. In contrast, oxidized LDL increased both cellular oxidative stress and PON2 expression.
CONCLUSIONS: HMDM-PON2 expression is reduced in patients with hypercholesterolemia as a result of their increased cellular cholesterol content. Atorvastatin therapy reduced both macrophage oxidative stress and cholesterol content, and upregulated PON2 expression, thus contributing to attenuation of foam cells formation.
ESTHER : Rosenblat_2004_Arterioscler.Thromb.Vasc.Biol_24_175
PubMedSearch : Rosenblat_2004_Arterioscler.Thromb.Vasc.Biol_24_175
PubMedID: 14592851

Title : Omapatrilat decreased macrophage oxidative status and atherosclerosis progression in atherosclerotic apolipoprotein E-deficient mice - Hayek_2004_J.Cardiovasc.Pharmacol_43_140
Author(s) : Hayek T , Hamoud S , Keidar S , Pavlotzky E , Coleman R , Aviram M , Kaplan M
Ref : J Cardiovasc Pharmacol , 43 :140 , 2004
Abstract : Oxidative stress is an important risk factor in the pathogenesis of atherosclerosis. Angiotensin-converting enzyme (ACE) inhibitors attenuate atherosclerosis and oxidative stress in animal models. Omapatrilat, a VasoPeptidase-inhibitor, selectively inhibits both Neutral-Endo-Peptidase (NEP) and ACE. OBJECTIVE: In this study, we analyzed the effect of Omapatrilat administration (1, 4, or 20mg/kg/d, for 12 weeks) to atherosclerotic apolipoprotein E-deficient (E0) mice on their blood pressure (BP), serum and macrophage oxidative status, and atherosclerotic lesion area.
RESULTS: Following administration of Omapatrilat (4 mg/kg/d and 20 mg/kg/d), the mice systolic and diastolic BP significantly decreased by up to 33% and 25% respectively, compared with placebo-treated mice. However, administration of Omapatrilat at 1mg/kg/d did not affect the mice BP. The Omapatrilat-treated mice serum susceptibility to lipid peroxidation was reduced by up to 21%, and their serum paraoxonase activity was increased by up to 24%, compared with placebo-treated mice. Peritoneal macrophages from Omapatrilat-treated (20 mg/kg/d) mice exhibited a reduced oxidative stress, evidenced by a reduction in macrophage lipid peroxide content (by 45%), cholesteryl-linoleate hydroperoxide content (by 48%), and oxidized glutathione levels (by 40%). Finally, the area of the mice atherosclerotic lesion was dose-dependently reduced, by 50%, 67%, and 82%, following Omapatrilat administration at 1mg/kg/d, 4 mg/kg/d, and 20 mg/kg/d respectively, compared with placebo-treated mice. CONCLUSION: Omapatrilat has a substantial anti-atherosclerotic effect, which can be related not only to BP reduction but also to its ability to reduce oxidative stress in atherosclerotic E0 mice.
ESTHER : Hayek_2004_J.Cardiovasc.Pharmacol_43_140
PubMedSearch : Hayek_2004_J.Cardiovasc.Pharmacol_43_140
PubMedID: 14668580

Title : Paraoxonase 2 (PON2) expression is upregulated via a reduced-nicotinamide-adenine-dinucleotide-phosphate (NADPH)-oxidase-dependent mechanism during monocytes differentiation into macrophages - Shiner_2004_Free.Radic.Biol.Med_37_2052
Author(s) : Shiner M , Fuhrman B , Aviram M
Ref : Free Radic Biol Med , 37 :2052 , 2004
Abstract : Paraoxonase 2 (PON2) is a member of the paraoxonases gene family. PON2 is ubiquitously present in cells, including macrophages, and it was shown to protect against cellular oxidative stress. The aim of the present study was to analyze mechanisms involved in PON2 expression during monocyte/macrophage differentiation. PON2 expression was analyzed in vitro in THP-1 cells differentiated with 1alpha,25-dihydroxyvitamin D3 and in vivo in mouse peritoneal macrophages (MPM) isolated at increasing time intervals after intraperitoneal thioglycollate injection. PON2 expression (mRNA and protein) and activity gradually increased during monocyte/macrophage differentiation, up to five fold and eight fold in vitro and in vivo, respectively. This effect was associated with a gradual increase in cellular superoxide anion production. Supplementation of vitamin E to Balb/C mice inhibited the reduced nicotinamide adenine dinuleotide phosphate (NADPH)-oxidase-dependent increase in cellular superoxide anion production by 50% and down-regulated PON2 mRNA expression and activity by 30 and 60%, respectively. Furthermore, PON2 expression was lower by nine fold in MPM isolated from P47(phox-/-) (inactive NADPH oxidase) mice, in comparison to MPM from control mice. PON2 expression was found to be regulated, at least in part, by the transcription factor AP-1, as suggested by decreased JDP2 (AP-1 repressor) protein expression in the nucleus and by decreased PON2 expression in the presence of a Jun N-terminal kinase inhibitor (SP600125). The present study demonstrates, for the first time, that PON2 expression increases in monocytes during their maturation into macrophage as a result of NADPH-oxidase activation, and this process is partly regulated by the transcription factor AP-1. PON2 stimulation may represent a compensatory mechanism against the increase in cellular superoxide anion production and atherogenesis.
ESTHER : Shiner_2004_Free.Radic.Biol.Med_37_2052
PubMedSearch : Shiner_2004_Free.Radic.Biol.Med_37_2052
PubMedID: 15544923

Title : Mouse macrophage paraoxonase 2 activity is increased whereas cellular paraoxonase 3 activity is decreased under oxidative stress - Rosenblat_2003_Arterioscler.Thromb.Vasc.Biol_23_468
Author(s) : Rosenblat M , Draganov DI , Watson CE , Bisgaier CL , La Du BN , Aviram M
Ref : Arterioscler Thromb Vasc Biol , 23 :468 , 2003
Abstract : OBJECTIVE: To determine whether paraoxonases (PONs) are expressed in macrophages and to analyze the oxidative stress effect on their expression and activities. METHODS AND
RESULTS: We demonstrated the presence (mRNA, protein, activity) of PON2 and PON3 but not PON1 in murine macrophages, whereas in human macrophages, only PON2 was expressed. Under oxidative stress as present in mouse peritoneal macrophages (MPMs) from apoE-deficient (E0) mice as well as in C57BL6 mice, MPMs that were incubated with buthionine sulfoximine, with angiotensin II, with 7-ketocholesterol, or with oxidized phosphatidylcholine, PON2 mRNA levels and lactonase activity toward dihydrocoumarin significantly increased (by 50% to 130%). In contrast, PON3 lactonase activity toward lovastatin was markedly reduced (by 29% to 57%) compared with control cells. The supplementation of E0 mice with dietary antioxidants (vitamin E, pomegranate juice) significantly increased macrophage PON3 activity (by 23% to 40%), suggesting that oxidative stress was the cause for the reduced macrophage PON3 activity. Incubation of purified PON2 or PON3 with E0 mice MPMs resulted in reduced cellular lipid peroxides content by 14% to 19% and inhibition of cell-mediated LDL oxidation by 32% to 39%.
CONCLUSIONS: Increased macrophage PON2 expression under oxidative stress could represent a selective cellular response to reduce oxidative burden, which may lead to attenuation of macrophage foam cell formation.
ESTHER : Rosenblat_2003_Arterioscler.Thromb.Vasc.Biol_23_468
PubMedSearch : Rosenblat_2003_Arterioscler.Thromb.Vasc.Biol_23_468
PubMedID: 12615656

Title : Paraoxonase (PON1) deficiency is associated with increased macrophage oxidative stress: studies in PON1-knockout mice - Rozenberg_2003_Free.Radic.Biol.Med_34_774
Author(s) : Rozenberg O , Rosenblat M , Coleman R , Shih DM , Aviram M
Ref : Free Radic Biol Med , 34 :774 , 2003
Abstract : Human serum paraoxonase (PON1), an HDL-associated esterase, protects lipoproteins against oxidation, probably by hydrolyzing specific lipid peroxides. As arterial macrophages play a key role in oxidative stress in early atherogenesis, the aim of the present study was to examine the effect of PON1 on macrophage oxidative stress. For this purpose we used mouse arterial and peritoneal macrophages (MPM) that were harvested from two populations of PON1 knockout (KO) mice: one on the genetic background of C57BL/6J (PON1(0)) and the other one on the genetic background of apolipoproteinE KO (PON1(0)/E(0)). Serum and LDL, but not HDL, lipids peroxidation was increased in PON1(0), compared to C57BL/6J mice, by 84% and by 220%, respectively. Increased oxidative stress was shown in peritoneal and in arterial macrophages derived from either PON1(0) or PON1(0)/E(0) mice, compared to their appropriate controls. Macrophage oxidative stress was expressed by increased lipid peroxides content in MPM from PON1(0) and from PON1(0)/E(0) mice by 48% and by 80%, respectively, and by decreased reduced glutathione (GSH) content, compared to the appropriate controls. Furthermore, increased capacity of MPM from PON1(0) and PON1(0)/E(0) mice to oxidize LDL (by 40% and by 19%, respectively) and to release superoxide anions was observed. In accordance with these results, PON1(0) mice MPM exhibited 130% increased translocation of the cytosolic p47phox component of NADPH-oxidase to the macrophage plasma membrane, suggesting increased activation of macrophage NADPH-oxidase in PON1(0) mice, compared to control mice MPM. The increase in oxidative stress in PON1-deficient mice was observed despite the presence of the two other members of the PON gene family. PON2 and PON3 activities and mRNA expression were both found to be present in PON1-deficient mice MPM. Upon incubation of PON1(0)/E(0) derived macrophages with human PON1 (7.5 arylesterase units/ml), cellular peroxides content was decreased by 18%, macrophage superoxide anion release was decreased by 33%, and macrophage-mediated oxidation of LDL was reduced by 22%. Finally, a 42% increase in the atherosclerotic lesion area was observed in PON1(0)/E(0) mice, in comparison to E(0) mice under regular chow diet. We thus concluded that PON1 can directly reduce oxidative stress in macrophages and in serum, and that PON1-deficiency results in increased oxidative stress not only in serum, but also in macrophages, a phenomenon that can contribute to the accelerated atherosclerosis shown in PON1-deficient mice.
ESTHER : Rozenberg_2003_Free.Radic.Biol.Med_34_774
PubMedSearch : Rozenberg_2003_Free.Radic.Biol.Med_34_774
PubMedID: 12633754

Title : Human serum paraoxonase 1 decreases macrophage cholesterol biosynthesis: possible role for its phospholipase-A2-like activity and lysophosphatidylcholine formation - Rozenberg_2003_Arterioscler.Thromb.Vasc.Biol_23_461
Author(s) : Rozenberg O , Shih DM , Aviram M
Ref : Arterioscler Thromb Vasc Biol , 23 :461 , 2003
Abstract : OBJECTIVE: Human serum paraoxonase 1 (PON1) activity is inversely related to the risk of developing an atherosclerotic lesion, which contains cholesterol-loaded macrophage foam cells. To assess a possible mechanism for this relationship, we analyzed the effect of PON1 on cellular cholesterol biosynthesis. METHODS AND
RESULTS: Mouse peritoneal macrophages (MPMs) were harvested from PON1-deficient mice (PON1o and PON1o/Eo mice on the genetic background of C57BL/6J and Eo mice, respectively). PON1o/Eo mice exhibited a significantly 51% increased atherosclerotic lesion area and 35% increased macrophage cholesterol content compared with control E degrees mice. In parallel, macrophage cholesterol biosynthesis rates were increased in PON1-deficient mice MPMs by 50% compared with their controls. Incubation of macrophages with human PON1 revealed a dose-dependent inhibitory effect (up to 84%) on macrophage cholesterol biosynthesis. We demonstrated a PON1 phospholipase-A2-like activity on MPMs, evidenced by release of polyunsaturated fatty acids and formation of lysophosphatidylcholine. On incubation of macrophages with lysophosphatidylcholine, a dose-dependent inhibition (up to 40%) of cellular cholesterol biosynthesis was noted. The inhibitory effect of PON1 on macrophage cholesterol biosynthesis was shown to be downstream to mevalonate, probably at the lanosterol metabolic point.
CONCLUSIONS: PON1 inhibits macrophage cholesterol biosynthesis and atherogenesis probably through its phospholipase-A2-like activity.
ESTHER : Rozenberg_2003_Arterioscler.Thromb.Vasc.Biol_23_461
PubMedSearch : Rozenberg_2003_Arterioscler.Thromb.Vasc.Biol_23_461
PubMedID: 12615663

Title : Tissue angiotensin-converting-enzyme (ACE) deficiency leads to a reduction in oxidative stress and in atherosclerosis: studies in ACE-knockout mice type 2 - Hayek_2003_Arterioscler.Thromb.Vasc.Biol_23_2090
Author(s) : Hayek T , Pavlotzky E , Hamoud S , Coleman R , Keidar S , Aviram M , Kaplan M
Ref : Arterioscler Thromb Vasc Biol , 23 :2090 , 2003
Abstract : Background- Angiotensin II, produced by angiotensin-converting-enzyme (ACE), enhances oxidative stress and atherogenesis. In this study, we analyzed whether tissue ACE deficiency in ACE-knockout mice type-2 would affect their oxidative status. Moreover, by crossbreeding the ACE-knockout mice with atherosclerotic apolipoprotein E (apo E)-deficient (E0) mice, we questioned whether tissue ACE deficiency affects atherogenesis. METHODS AND
RESULTS: ACE-deficient mice type-2 (ACE+/-) exhibited reduced serum lipid peroxidation compared with ACE+/+ mice. Peritoneal macrophages from ACE+/- mice demonstrated lower oxidative status, as exhibited by decreases of 47%, 33% 56%, and 51%, in their lipid peroxides, superoxide release, dichlorofluorescein fluorescence, and LDL oxidation, respectively, compared with ACE+/+ mice. ACE+/- mice crossbred with E0 mice, resulting in atherosclerotic mice heterozygous for ACE (ACE+/-/E0 mice), exhibited reduced lipid peroxidation, increased paraoxonase activity, and lower macrophage LDL oxidation compared with E0 and ACE+/+/E0 mice. ACE+/-/E0 mice also exhibited reduced NADPH-induced aortic superoxide ion production by 52% and a reduction of 43% in their atherosclerotic lesion size compared with E0 mice. Finally, 2 animals genotyped as homozygous-knockout for both ACE and APOE genes (ACE-/-/E0), exhibited a striking reduction of 86% in their atherosclerotic lesion area compared with E0 mice.
CONCLUSIONS: Reduction of tissue ACE with the ACE-knockout mouse type-2 model inhibited oxidative stress and atherogenesis.
ESTHER : Hayek_2003_Arterioscler.Thromb.Vasc.Biol_23_2090
PubMedSearch : Hayek_2003_Arterioscler.Thromb.Vasc.Biol_23_2090
PubMedID: 14525797

Title : Effect of eplerenone, a selective aldosterone blocker, on blood pressure, serum and macrophage oxidative stress, and atherosclerosis in apolipoprotein E-deficient mice - Keidar_2003_J.Cardiovasc.Pharmacol_41_955
Author(s) : Keidar S , Hayek T , Kaplan M , Pavlotzky E , Hamoud S , Coleman R , Aviram M
Ref : J Cardiovasc Pharmacol , 41 :955 , 2003
Abstract : Oxidative stress is involved in the pathogenesis of atherosclerosis, and angiotensin II (AT-II) induces oxidative stress and enhances atherogenesis. Aldosterone, which has an important role in the pathology of heart failure, has recently been implicated as a mediator of AT-II biologic activities. In this study, we analyzed whether administration of the selective aldosterone blocker eplerenone to atherosclerotic apolipoprotein E-deficient (E0) mice would affect their oxidative status and atherogenesis. Apolipoprotein E-deficient mice were administered chow containing eplerenone (200 mg/kg/day) for 3 months. Blood pressure, serum and macrophage oxidative status, and aortic atherosclerotic lesion area were evaluated in mice treated with eplerenone compared with untreated mice. Eplerenone administration significantly decreased systolic and diastolic blood pressure by 12% and 11%, respectively, compared with untreated mice. Serum susceptibility to lipid peroxidation decreased by as much as 26%, and serum paraoxonase activity increased by 28% in eplerenone-treated mice compared with untreated mice. Peritoneal macrophages from eplerenone-treated mice contained reduced levels of lipid peroxides, and their macrophage oxidation of low-density lipoprotein (LDL) and superoxide ion release were significantly reduced (by 17% and 43%, respectively), compared to untreated mice. Daily injections of AT-II (0.1 mL, 10(-)7M) during the final 3 weeks of the study in eplerenone-treated mice substantially attenuated the eplerenone-mediated reduction in macrophage superoxide release and LDL oxidation. Finally, the atherosclerotic lesion area in aortas of eplerenone-treated mice was significantly reduced (by 35%) versus untreated mice, and this effect was reversed by AT-II. Administration of the selective aldosterone blocker eplerenone significantly reduced oxidative stress and atherosclerosis progression in E0 mice. These data suggest that aldosterone could have a significant pro-oxidative role in the pathogenesis of atherosclerosis.
ESTHER : Keidar_2003_J.Cardiovasc.Pharmacol_41_955
PubMedSearch : Keidar_2003_J.Cardiovasc.Pharmacol_41_955
PubMedID: 12775976

Title : Preservation of paraoxonase activity by wine flavonoids: possible role in protection of LDL from lipid peroxidation - Fuhrman_2002_Ann.N.Y.Acad.Sci_957_321
Author(s) : Fuhrman B , Aviram M
Ref : Annals of the New York Academy of Sciences , 957 :321 , 2002
Abstract : Paraoxonase is an esterase physically associated with HDL, and its activity has been shown to be inversely related to the risk of cardiovascular diseases. We have shown that paraoxonase can hydrolyze specific lipid peroxides in oxidized lipoproteins and in atherosclerotic lesions. Paroxonase was shown to be inactivated by oxidative stress. Consumption of wine flavonoids was shown to preserve paraoxonase activity by reducing the oxidative stress in apolipoprotein E-deficient mice, thereby contributing to paraoxonase hydrolytic activity on lipid peroxides in oxidized lipoproteins and atherosclerotic lesions.
ESTHER : Fuhrman_2002_Ann.N.Y.Acad.Sci_957_321
PubMedSearch : Fuhrman_2002_Ann.N.Y.Acad.Sci_957_321
PubMedID: 12074989

Title : Pomegranate juice flavonoids inhibit low-density lipoprotein oxidation and cardiovascular diseases: studies in atherosclerotic mice and in humans - Aviram_2002_Drugs.Exp.Clin.Res_28_49
Author(s) : Aviram M , Dornfeld L , Kaplan M , Coleman R , Gaitini D , Nitecki S , Hofman A , Rosenblat M , Volkova N , Presser D , Attias J , Hayek T , Fuhrman B
Ref : Drugs Under Experimental & Clinical Research , 28 :49 , 2002
Abstract : The beneficial health effects attributed to the consumption of fruit and vegetables are related, at least in part, to their antioxidant activity. Of special interest is the inverse relationship between the intake of dietary nutrients rich in polyphenols and cardiovascular diseases. This effect is attributed to polyphenols' ability to inhibit low-density lipoprotein (LDL) oxidation, macrophage foam cell formation and atherosclerosis. Pomegranate polyphenols can protect LDL against cell-mediated oxidation via two pathways, including either direct interaction of the polyphenols with the lipoprotein and/or an indirect effect through accumulation of polyphenols in arterial macrophages. Pomegranate polyphenols were shown to reduce the capacity of macrophages to oxidatively modify LDL, due to their interaction with LDL to inhibit its oxidation by scavenging reactive oxygen species and reactive nitrogen species and also due to accumulation of polyphenols in arterial macrophages; hence, the inhibition of macrophage lipid peroxidation and the formation of lipid peroxide-rich macrophages. Furthermore, pomegranate polyphenols increase serum paraoxonase activity, resulting in the hydrolysis of lipid peroxides in oxidized lipoproteins and in atherosclerotic lesions. These antioxidative and antiatherogenic effects of pomegranate polyphenols were demonstrated in vitro, as well as in vivo in humans and in atherosclerotic apolipoprotein E deficient mice. Dietary supplementation of polyphenol-rich pomegranate juice to atherosclerotic mice significantly inhibited the development of atherosclerotic lesions and this may be attributed to the protection of LDL against oxidation.
ESTHER : Aviram_2002_Drugs.Exp.Clin.Res_28_49
PubMedSearch : Aviram_2002_Drugs.Exp.Clin.Res_28_49
PubMedID: 12224378

Title : Wine flavonoids protect against LDL oxidation and atherosclerosis - Aviram_2002_Ann.N.Y.Acad.Sci_957_146
Author(s) : Aviram M , Fuhrman B
Ref : Annals of the New York Academy of Sciences , 957 :146 , 2002
Abstract : We have previously shown that consumption of red wine, but not of white wine, by healthy volunteers, resulted in the enrichment of their plasma LDL with flavonoid antioxidants such as quercetin, the potent free radicals scavenger flavanol, which binds to the LDL via a glycosidic ether bond. This phenomenon was associated with a significant three-fold reduction in copper ion-induced LDL oxidation. The ineffectiveness of flavonoid-poor white wine could be overcome by grape's skin contact for 18 hours in the presence of alcohol, which extracts grape's skin flavonoids. Recently, we observed that the high antioxidant potency of Israeli red wine could be related to an increased content of flavonols, which are very potent antioxidants and their biosynthesis is stimulated by sunlight exposure. To find out the effect (and mechanisms) of red wine consumption on atherosclerosis, we used the apo E deficient (E(0)) mice. In these mice, red wine consumption for two months resulted in a 40% decrement in basal LDL oxidation, a similar decrement in LDL oxidizability and aggregation, a 35% reduction in lesion size, and a marked attenuation in the number and morphology of lesion's macrophage foam cells. Red wine consumption resulted in accumulation of flavonoids in the mouse macrophages and these cells oxidized LDL and took up LDL about 40% less than macrophages from placebo-treated mice. Finally, the activity of serum paraoxonase (which can hydrolyze specific lipid peroxides in oxidized LDL and in atherosclerotic lesions) was significantly increased following consumption of red wine by E(0) mice. Red wine consumption thus acts against the accumulation of oxidized LDL in lesions as a first line of defense (by a direct inhibition of LDL oxidation), and as a second line of defense (by paraoxonase elevation and removal of atherogenic lesion's and lipoprotein's oxidized lipids).
ESTHER : Aviram_2002_Ann.N.Y.Acad.Sci_957_146
PubMedSearch : Aviram_2002_Ann.N.Y.Acad.Sci_957_146
PubMedID: 12074969

Title : Atorvastatin therapy in hypercholesterolemic patients suppresses cellular uptake of oxidized-LDL by differentiating monocytes - Fuhrman_2002_Atherosclerosis_164_179
Author(s) : Fuhrman B , Koren L , Volkova N , Keidar S , Hayek T , Aviram M
Ref : Atherosclerosis , 164 :179 , 2002
Abstract : Atherosclerosis is characterized by macrophage foam cells formation, which originate from differentiating blood monocytes that have taken up oxidized LDL (Ox-LDL) at enhanced rate. Statin therapy exhibit pleiotropic effects on many components of atherosclerosis. We have studied the effect of atorvastatin therapy in hypercholesterolemic patients, on the cellular uptake of Ox-LDL by their monocytes during differentiation into macrophages. Eleven hypercholesterolemic men were treated with 20 mg/day of atorvastatin for a period of 1 month. Peripheral blood monocytes harvested from control subjects and from patients before and after atorvastatin therapy were allowed to differentiate in culture for up to 9 days in the presence of 20% autologous serum. In control monocytes/macrophages the cellular uptake of Ox-LDL and the scavenger receptors CD36, SRA-I and SRA-II mRNA expression were upregulated during differentiation, and this upregulation was significantly enhanced in cells from hypercholesterolemic patients. Atorvastatin therapy suppressed the upregulation in Ox-LDL degradation and scavenger receptors expression in differentiating monocytes. These effects could be related at least in part to antioxidant characteristics of atorvastatin. Reduced susceptibility of plasma to free radical-induced lipid peroxidation (by 35%), increased plasma total antioxidant status (TAS; by 30%), and increased serum paraoxonase activity (by 53%), were noted following drug therapy. We conclude that atorvastatin therapy in hypercholesterolemic patients reduces the enhanced cellular uptake of Ox-LDL during ex-vivo differentiation of monocytes into macrophages, and decreases cellular scavenger receptors gene expression. These effects may account for the attenuation of atherogenesis in hypercholesterolemic patients following atorvastatin treatment.
ESTHER : Fuhrman_2002_Atherosclerosis_164_179
PubMedSearch : Fuhrman_2002_Atherosclerosis_164_179
PubMedID: 12119208

Title : Oxidative stress increases the expression of the CD36 scavenger receptor and the cellular uptake of oxidized low-density lipoprotein in macrophages from atherosclerotic mice: protective role of antioxidants and of paraoxonase - Fuhrman_2002_Atherosclerosis_161_307
Author(s) : Fuhrman B , Volkova N , Aviram M
Ref : Atherosclerosis , 161 :307 , 2002
Abstract : Little is known about the effects of oxidative stress on macrophage lipid peroxidation and on their atherogenic consequences. Therefore, we questioned the causal relationship between cellular lipid peroxides content and macrophage uptake of oxidized low-density lipoprotein (Ox-LDL). Lipid peroxide content in mouse peritoneal macrophages (MPMs) from E-deficient (E(0)) mice increased progressively by up to 4.6 fold during mice aging, and this was accompanied by an age-dependent increase in the cellular uptake of Ox-LDL (90%), and in the expression of the scavenger receptor CD36 mRNA (41%). Inhibition or stimulation of cellular oxidative stress by administration of dietary potent antioxidants (vitamin E or glabridin) or by inducing cellular glutathione depletion (by using buthionine sulfoximine), respectively, resulted in a significant increment or inhibition of macrophage uptake of Ox-LDL and in cellular CD36 mRNA expression, respectively. Intraperitoneal injection of human serum paraoxonase (PON1) into E(0) mice, resulted in a 40-65% decrement in the lipid peroxide content in MPM harvested from E(0) mice at 2-5 months of age, which subsequently resulted in a similar reduced uptake of Ox-LDL and expression of CD36 mRNA (by 30-40%). In conclusion, our results are the first to demonstrate that macrophage lipid peroxidation stimulates CD36 mRNA expression and enhances the cellular uptake of Ox-LDL.
ESTHER : Fuhrman_2002_Atherosclerosis_161_307
PubMedSearch : Fuhrman_2002_Atherosclerosis_161_307
PubMedID: 11888513

Title : Serum paraoxonase activity and the extent of lipid peroxidation are not affected by increased levels of human apolipoprotein A-I: studies in transgenic mice - Rosenblat_2002_Clin.Chem.Lab.Med_40_9
Author(s) : Rosenblat M , Grunfeld O , Hayek T , Aviram M
Ref : Clinical Chemistry & Laboratory Medicine , 40 :9 , 2002
Abstract : The present study analyzed the effect of increased concentrations of human apolipoprotein (apo) A-I in transgenic mice serum on paraoxonase activity and on lipid peroxidation. In the transgenic mice serum, in comparison to control (non-transgenic) C57BL/6 mice, we found high concentrations of human apoA-I and high-density lipoprotein (HDL)-cholesterol, but serum lipid peroxidation (basal and free radical-induced) and serum paraoxonase activity were similar in the two mouse groups. Comparing the individual results, no significant correlation was found between free radical-induced serum lipid peroxidation and apoA-I concentrations. Serum paraoxonase activity also did not correlate with serum concentrations of human apoA-I. However, a significant inverse relationship (R2=0.75) was observed between the individual values of paraoxonase activity and free radical-induced lipid peroxidation in both mouse groups. Direct analysis of the effect of pure human apoA-I and paraoxonase (using the specific paraoxonase inhibitor PD-92770) on lipid peroxidation also revealed that paraoxonase, but not apoA-I, protects serum lipids from oxidation. We thus conclude that the increased human apoA-I concentration in the mouse serum neither affect serum paraoxonase activity, nor protects against lipid peroxidation, whereas paraoxonase significantly inhibits serum lipid peroxidation.
ESTHER : Rosenblat_2002_Clin.Chem.Lab.Med_40_9
PubMedSearch : Rosenblat_2002_Clin.Chem.Lab.Med_40_9
PubMedID: 11916277

Title : Pomegranate juice supplementation to atherosclerotic mice reduces macrophage lipid peroxidation, cellular cholesterol accumulation and development of atherosclerosis - Kaplan_2001_J.Nutr_131_2082
Author(s) : Kaplan M , Hayek T , Raz A , Coleman R , Dornfeld L , Vaya J , Aviram M
Ref : J Nutr , 131 :2082 , 2001
Abstract : Inhibition of lipid peroxidation contributes to the attenuation of macrophage cholesterol accumulation, foam-cell formation and atherosclerosis. Evidence suggests that nutritional antioxidants such as pomegranate juice (PJ) can contribute to the reduction of oxidative stress and atherogenesis. The goals of the present study were to determine whether such beneficial effects of PJ exist when supplemented to apolipoprotein E-deficient (E(0)) mice with advanced atherosclerosis and to analyze the antiatherosclerotic activity of a tannin-fraction isolated from PJ. Mice (4-mo-old) were supplemented with PJ in their drinking water for 2 mo and compared with age-matched placebo-treated mice, as well as to young (4-mo-old) control mice, for their mouse peritoneal macrophage (MPM) oxidative state, cholesterol flux and mice atherosclerotic lesion size. PJ supplementation reduced each of the proatherogenic variables determined in the present study compared with age-matched placebo-treated mice. It significantly induced serum paraoxonase activity and reduced MPM lipid peroxide content compared with placebo-treated mice and control mice. PJ administration to E(0) mice significantly reduced the oxidized (Ox)-LDL MPM uptake by 31% and MPM cholesterol esterification and increased macrophage cholesterol efflux by 39% compared with age-matched, placebo-treated mice. PJ consumption reduced macrophage Ox-LDL uptake and cholesterol esterification to levels lower than those in 4-mo-old, unsupplemented controls. PJ supplementation to E(0) mice with advanced atherosclerosis reduced the lesion size by 17% compared with placebo-treated mice. In a separate study, supplementation of young (2-mo-old) E(0) mice for 2 mo with a tannin fraction isolated from PJ reduced their atherosclerotic lesion size, paralleled by reduced plasma lipid peroxidation and decreased Ox-LDL MPM uptake. PJ supplementation to mice with advanced atherosclerosis reduced their macrophage oxidative stress, their macrophage cholesterol flux and even attenuated the development of atherosclerosis. Moreover, a tannin-fraction isolated from PJ had a significant antiatherosclerotic activity.
ESTHER : Kaplan_2001_J.Nutr_131_2082
PubMedSearch : Kaplan_2001_J.Nutr_131_2082
PubMedID: 11481398

Title : Review of human studies on oxidative damage and antioxidant protection related to cardiovascular diseases - Aviram_2000_Free.Radic.Res_33 Suppl_S85
Author(s) : Aviram M
Ref : Free Radical Research , 33 Suppl :S85 , 2000
Abstract : Under oxidative stress, which is associated with atherosclerosis, oxidative modifications of LDL take place. A major effect of antioxidants in the LDL environment is to prevent the formation of oxidized LDL during atherogenesis. The question that arises is what are the body's capabilities to inhibit LDL oxidation and to remove and/or to neutralize atherogenic Ox-LDL when formed. Strategies to reduce LDL oxidation and atherogenesis can involve the enrichment of the LDL and arterial cells with potent antioxidants that can prevent oxidative damage to the arterial wall. There seems to be a clear cause and effect relationship between LDL oxidation and atherosclerosis. Atherosclerosis is a multifactorial disease and LDL is oxidized by all major cells of the arterial wall during the development of atherosclerosis via more than one mechanism. The various LDL oxidation pathways produce several lipid peroxidation products such as isoprostanes from arachidonic, eicosapentaenoic and docosahexaenoic acids, oxysterols from unesterified and esterified cholesterol, hydroxy fatty acids, lipid peroxides and aldehydes. Thus, one single assay of lipid peroxidation is probably not sufficient to serve as a marker for cardiovascular risk and there is a need for measurements of several markers. The use of biomarkers provides a logical scientific basis for major intervention trials of antioxidants; such trials will, in turn, eventually validate or disprove the biomarker concept. Any intervention trial that does take place should be accompanied by measurements of one or more relevant biomarkers at intervals during the study. If the endpoint of the trial is disease incidence or mortality, such studies will help to validate or disprove the biomarker concept. They might also help to explore the possibility that in vivo levels of oxidative lipid damage are early predictors of subsequent development of cardiovascular disease. In addition, specific antioxidants in serum, as well as serum paraoxonase activity can provide very useful information on the risk for cardiovascular diseases. For vascular disease risk, in addition to the markers in use for lipid peroxidation, there is a need to include also markers for endothelial dysfunction, monocyte adhesion, macrophage uptake of lipoproteins, thrombotic, and inflammatory processes.
ESTHER : Aviram_2000_Free.Radic.Res_33 Suppl_S85
PubMedSearch : Aviram_2000_Free.Radic.Res_33 Suppl_S85
PubMedID: 11191279

Title : Pomegranate juice consumption reduces oxidative stress, atherogenic modifications to LDL, and platelet aggregation: studies in humans and in atherosclerotic apolipoprotein E-deficient mice - Aviram_2000_Am.J.Clin.Nutr_71_1062
Author(s) : Aviram M , Dornfeld L , Rosenblat M , Volkova N , Kaplan M , Coleman R , Hayek T , Presser D , Fuhrman B
Ref : Am J Clin Nutr , 71 :1062 , 2000
Abstract : BACKGROUND: Dietary supplementation with nutrients rich in antioxidants is associated with inhibition of atherogenic modifications to LDL, macrophage foam cell formation, and atherosclerosis. Pomegranates are a source of polyphenols and other antioxidants. OBJECTIVE: We analyzed, in healthy male volunteers and in atherosclerotic apolipoprotein E-deficient (E(0)) mice, the effect of pomegranate juice consumption on lipoprotein oxidation, aggregation, and retention; macrophage atherogenicity; platelet aggregation; and atherosclerosis. DESIGN: Potent antioxidative effects of pomegranate juice against lipid peroxidation in whole plasma and in isolated lipoproteins (HDL and LDL) were assessed in humans and in E(0) mice after pomegranate juice consumption for <=2 and 14 wk, respectively.
RESULTS: In humans, pomegranate juice consumption decreased LDL susceptibility to aggregation and retention and increased the activity of serum paraoxonase (an HDL-associated esterase that can protect against lipid peroxidation) by 20%. In E(0) mice, oxidation of LDL by peritoneal macrophages was reduced by up to 90% after pomegranate juice consumption and this effect was associated with reduced cellular lipid peroxidation and superoxide release. The uptake of oxidized LDL and native LDL by mouse peritoneal macrophages obtained after pomegranate juice administration was reduced by 20%. Finally, pomegranate juice supplementation of E(0) mice reduced the size of their atherosclerotic lesions by 44% and also the number of foam cells compared with control E(0) mice supplemented with water. CONCLUSION: Pomegranate juice had potent antiatherogenic effects in healthy humans and in atherosclerotic mice that may be attributable to its antioxidative properties.
ESTHER : Aviram_2000_Am.J.Clin.Nutr_71_1062
PubMedSearch : Aviram_2000_Am.J.Clin.Nutr_71_1062
PubMedID: 10799367

Title : Human serum paraoxonases (PON1) Q and R selectively decrease lipid peroxides in human coronary and carotid atherosclerotic lesions: PON1 esterase and peroxidase-like activities - Aviram_2000_Circulation_101_2510
Author(s) : Aviram M , Hardak E , Vaya J , Mahmood S , Milo S , Hoffman A , Billicke S , Draganov DI , Rosenblat M
Ref : Circulation , 101 :2510 , 2000
Abstract : BACKGROUND: Human serum paraoxonase (PON1) exists in two polymorphic forms: one that differs in the amino acid at position 192 (glutamine and arginine, Q and R, respectively) and the second one that differs in the amino acid at position 55 (methionine and leucine, M and L, respectively). PON1 protects LDL from oxidation, and during LDL oxidation, PON1 is inactivated. METHODS AND
RESULTS: The present study compared PON1 isoforms Q and R for their effect on lipid peroxide content in human coronary and carotid lesions. After 24 hours of incubation with PON1Q or PON1R (10 arylesterase units/mL), lipid peroxides content in both coronary and carotid lesion homogenates (0.1 g/mL) was reduced up to 27% and 16%, respectively. The above incubation was associated with inactivation of PON1Q and PON1R by 15% and 45%, respectively. Lesion cholesteryl linoleate hydroperoxides and cholesteryl linoleate hydroxides were hydrolyzed by PON1 to yield linoleic acid hydroperoxides and linoleic acid hydroxides. Furthermore, lesion and pure linoleic acid hydroperoxides were reduced to yield linoleic acid hydroxides. These results thus indicate that PON1 demonstrates esterase-like and peroxidase-like activities. Recombinant PON1 mutants in which the PON1-free sulfhydryl group at cysteine-284 was replaced with either alanine or serine were no longer able to reduce lipid peroxide content in carotid lesions.
CONCLUSIONS: We conclude that PON1 may be antiatherogenic because it hydrolyzes lipid peroxides in human atherosclerotic lesions.
ESTHER : Aviram_2000_Circulation_101_2510
PubMedSearch : Aviram_2000_Circulation_101_2510
PubMedID: 10831526

Title : [Cholesterol oxidation, macrophage foam cells and atherosclerosis: importance of antioxidants and paraoxonase] -
Author(s) : Aviram M
Ref : Harefuah , 136 :620 , 1999
PubMedID: 10955072

Title : Does paraoxonase play a role in susceptibility to cardiovascular disease? - Aviram_1999_Mol.Med.Today_5_381
Author(s) : Aviram M
Ref : Mol Med Today , 5 :381 , 1999
Abstract : Human serum paraoxonase (PON1) is an esterase that is bound to high-density lipoproteins (HDLs). It can hydrolyze organophosphates and its activity is inversely related to atherosclerosis. Some studies also suggest that a relationship exists between polymorphisms of the gene that encodes paraoxonase and coronary heart disease (CHD), whereas other studies, in different populations, have not found such an association. One mechanism by which certain PON1 allozymes might protect against atherosclerosis is by inhibition of the oxidation of HDL and low-density lipoprotein (LDL). Experimental studies suggest that this protection is associated with the ability of PON1 to hydrolyze specific lipid peroxides in oxidized lipoproteins. Interventions that preserve or enhance PON1 activity, as well as manipulations of PON1 polymorphisms, might help delay the onset of CHD.
ESTHER : Aviram_1999_Mol.Med.Today_5_381
PubMedSearch : Aviram_1999_Mol.Med.Today_5_381
PubMedID: 10462749

Title : Macrophage foam cell formation during early atherogenesis is determined by the balance between pro-oxidants and anti-oxidants in arterial cells and blood lipoproteins - Aviram_1999_Antioxid.Redox.Signal_1_585
Author(s) : Aviram M
Ref : Antioxid Redox Signal , 1 :585 , 1999
Abstract : Atherosclerosis is a multifactorial disease, where more than one mechanism, along more than one step, contributes to macrophage cholesterol accumulation and foam cell formation, the hallmark of early atherogenesis. Arterial macrophages take up oxidized low-density lipoproteins (Ox-LDL), leading to cellular accumulation of cholesterol and oxysterols. Atherogenic modifications of LDL include, in addition to oxidation, retention and aggregation. Intervention to inhibit LDL oxidation can affect the above additional LDL modifications. Indeed, we have demonstrated in the atherosclerotic apolipoprotein E-deficient mice that consumption of vitamin E or of flavonoids from red wine or licorice decreased LDL oxidation, LDL retention, and LDL aggregation and attenuated macrophage foam cell formation and atherosclerosis. The balance between pro-oxidants and anti-oxidants in the LDL particle (such as cholesteryl ester vs. vitamin E), as well as in arterial wall macrophages (such as NADPH oxidase vs. glutathione), determines the extent of LDL oxidation. Antioxidants can protect LDL from oxidation not only by their binding to the lipoprotein, but also following their accumulation in cells of the arterial wall. Whereas antioxidants can prevent the formation of Ox-LDL, human serum paraoxonase (PON 1), an HDL-associated esterase that hydrolyzes organophosphates, can eliminate oxidized LDL (by hydrolysis of its lipid peroxides), which is formed when antioxidant protection is not sufficient. Ox-LDL, in turn, can inactivate paraoxonase activity. Thus, the combination of antioxidants together with active paraoxonase decreases the formation of Ox-LDL and preserves PON1's ability to hydrolyze this atherogenic lipoprotein and hence, to attenuate atherosclerosis.
ESTHER : Aviram_1999_Antioxid.Redox.Signal_1_585
PubMedSearch : Aviram_1999_Antioxid.Redox.Signal_1_585
PubMedID: 11233155

Title : Human serum paraoxonase (PON 1) is inactivated by oxidized low density lipoprotein and preserved by antioxidants - Aviram_1999_Free.Radic.Biol.Med_26_892
Author(s) : Aviram M , Rosenblat M , Billecke S , Erogul J , Sorenson R , Bisgaier CL , Newton RS , La Du BN
Ref : Free Radic Biol Med , 26 :892 , 1999
Abstract : Human serum paraoxonase (PON1) can protect low density lipoprotein (LDL) from oxidation induced by either copper ion or by the free radical generator azo bis amidinopropane hydrochloride (AAPH). During LDL oxidation in both of these systems, a time-dependent inactivation of PON arylesterase activity was observed. Oxidized LDL (Ox-LDL) produced by lipoprotein incubation with either copper ion or with AAPH, indeed inactivated PON arylesterase activity by up to 47% or 58%, respectively. Three possible mechanisms for PON inactivation during LDL oxidation were considered and investigated: copper ion binding to PON, free radical attack on PON, and/or the effect of lipoprotein-associated peroxides on the enzyme. As both residual copper ion and AAPH are present in the Ox-LDL preparations and could independently inactivate the enzyme, the effect of minimally oxidized (Ox-LDL produced by LDL storage in the air) on PON activity was also examined. Oxidized LDL, as well as oxidized palmitoyl arachidonoyl phosphatidylcholine (PAPC), lysophosphatidylcholine (LPC, which is produced during LDL oxidation by phospholipase A2-like activity), and oxidized cholesteryl arachidonate (Ox-CA), were all potent inactivators of PON arylesterase activity (PON activity was inhibited by 35%-61%). PON treatment with Ox-LDL (but not with native LDL), or with oxidized lipids, inhibited its arylesterase activity and also reduced the ability of the enzyme to protect LDL against oxidation. PON Arylesterase activity however was not inhibited when PON was pretreated with the sulfhydryl blocking agent, p-hydroxymercurybenzoate (PHMB). Similarly, on using recombinant PON in which the enzyme's only free sulfhydryl group at the position of cysteine-284 was mutated, no inactivation of the enzyme arylesterase activity by Ox-LDL could be shown. These results suggest that Ox-LDL inactivation of PON involves the interaction of oxidized lipids in Ox-LDL with the PON's free sulfhydryl group. Antioxidants such as the flavonoids glabridin or quercetin, when present during LDL oxidation in the presence of PON, reduced the amount of lipoprotein-associated lipid peroxides and preserved PON activities, including its ability to hydrolyze Ox-LDL cholesteryl linoleate hydroperoxides. We conclude that PON's ability to protect LDL against oxidation is accompanied by inactivation of the enzyme. PON inactivation results from an interaction between the enzyme free sulfhydryl group and oxidized lipids such as oxidized phospholipids, oxidized cholesteryl ester or lysophosphatidylcholine, which are formed during LDL oxidation. The action of antioxidants and PON on LDL during its oxidation can be of special benefit against atherosclerosis since these agents reduce the accumulation of Ox-LDL by a dual effect: i.e. prevention of its formation, and removal of Ox-LDL associated oxidized lipids which are generated during LDL oxidation.
ESTHER : Aviram_1999_Free.Radic.Biol.Med_26_892
PubMedSearch : Aviram_1999_Free.Radic.Biol.Med_26_892
PubMedID: 10232833

Title : Properties of the retained N-terminal hydrophobic leader sequence in human serum paraoxonase\/arylesterase - Sorenson_1999_Chem.Biol.Interact_119-120_243
Author(s) : Sorenson RC , Aviram M , Bisgaier CL , Billecke S , Hsu C , La Du BN
Ref : Chemico-Biological Interactions , 119-120 :243 , 1999
Abstract : Human serum paraoxonase/arylesterase (PON1) is HDL-associated and appears to protect low density lipoproteins (LDL) from oxidation. Mature PON1 retains its N-terminal hydrophobic signal sequence, which may be needed for binding to HDL. By site-directed mutagenesis, we created a mutant PON1 (A19A20) with a cleavable N-terminus to determine if this peptide mediated binding to lipoproteins. As a model system, we studied binding of mutant and wild type PON1s to lipoproteins in fetal bovine serum-containing expression medium and found that the wild type recombinant enzyme associated with lipoproteins whereas the A19A20 mutant did not. These results show that the N-terminus is required for binding to either apolipoproteins or phospholipids. Furthermore, we showed that wild type enzyme can bind to phospholipids directly without apolipoproteins. To determine if lipid binding is a requirement for PON1's protection against LDL oxidation, we used a copper ion-induced oxidation system and found that the wild type enzyme and A19A20 mutant showed similar reductions in both peroxide and aldehyde formation. We conclude that PON1 depends upon its N-terminal hydrophobic peptide for its association with serum lipoproteins.
ESTHER : Sorenson_1999_Chem.Biol.Interact_119-120_243
PubMedSearch : Sorenson_1999_Chem.Biol.Interact_119-120_243
PubMedID: 10421458

Title : On the physiological role(s) of the paraoxonases - La Du_1999_Chem.Biol.Interact_119-120_379
Author(s) : La Du BN , Aviram M , Billecke S , Navab M , Primo-Parmo S , Sorenson RC , Standiford TJ
Ref : Chemico-Biological Interactions , 119-120 :379 , 1999
Abstract : In recent years several lines of evidence have indicated that serum paraoxonase (PON1), and perhaps other mammalian paraoxonases, act as important guardians against cellular damage from toxic agents, such as organophosphates, oxidized lipids in the plasma low density lipoproteins (LDL), and against bacterial endotoxins. For some of these protective activities but not all, PON1 requires calcium ion. The catalyzed chemical reactions generally seem to be hydrolytic, but for some types of protection this may not be so. Several other metals have very high affinity for PON1 and may displace calcium. Replacement or substitution of calcium by other metals could extend the range of catalytic properties and the substrate specificity of the paraoxonases, as it does for the mammalian DFPases. Although this Third International Meeting on Esterases Reacting with Organophosphorus Compounds focuses on the organophosphatase activities of paraoxonase and related enzymes, it is important to also briefly review some of the current directions in several laboratories searching for additional functions of the paraoxonases to extend our understanding of the properties of this family of enzymes which now seem to have both physiological and toxicological importance.
ESTHER : La Du_1999_Chem.Biol.Interact_119-120_379
PubMedSearch : La Du_1999_Chem.Biol.Interact_119-120_379
PubMedID: 10421474

Title : Oxidized low density lipoprotein: atherogenic and proinflammatory characteristics during macrophage foam cell formation. An inhibitory role for nutritional antioxidants and serum paraoxonase - Kaplan_1999_Clin.Chem.Lab.Med_37_777
Author(s) : Kaplan M , Aviram M
Ref : Clinical Chemistry & Laboratory Medicine , 37 :777 , 1999
Abstract : Oxidative stress and inflammatory processes are of major importance in atherogenesis because they stimulate oxidized LDL (Ox-LDL)-induced macrophage cholesterol accumulation and foam cell formation, the hallmark of early atherosclerosis. Under oxidative stress, both blood monocytes and plasma lipoproteins invade the arterial wall, where they are exposed to atherogenic modifications. Oxidative stress stimulates endothelial secretion of monocyte chemoattractant protein 1 (MCP-1) and of macrophage colony stimulating factor (M-CSF), leading to monocyte adhesion and differentiation, respectively. LDL binds to extracellular matrix (ECM secreted by endothelial cells, smooth muscle cells and macrophages) proteoglycans, in a process that contributes to the enhanced susceptibility of the lipoprotein to oxidation by arterial wall macrophages. ECM-retained Ox-LDL is taken up by activated macrophages via their scavenger receptors. This leads to cellular cholesterol accumulation and enhanced atherogenesis. Protection of LDL against oxidation by antioxidants that can act directly on the LDL, or indirectly on the cellular oxidative machinery, or conversion of Ox-LDL to a non-atherogenic particle by HDL-associated paraoxonase (PON-1), can contribute to attenuation of atherosclerosis.
ESTHER : Kaplan_1999_Clin.Chem.Lab.Med_37_777
PubMedSearch : Kaplan_1999_Clin.Chem.Lab.Med_37_777
PubMedID: 10536926

Title : Human serum Paraoxonase\/Arylesterase's retained hydrophobic N-terminal leader sequence associates with HDLs by binding phospholipids : apolipoprotein A-I stabilizes activity - Sorenson_1999_Arterioscler.Thromb.Vasc.Biol_19_2214
Author(s) : Sorenson RC , Bisgaier CL , Aviram M , Hsu C , Billecke S , La Du BN
Ref : Arterioscler Thromb Vasc Biol , 19 :2214 , 1999
Abstract : In serum, human paraoxonase/arylesterase (PON1) is found exclusively associated with high density lipoprotein (HDL) and contributes to its antiatherogenic properties by inhibiting low density lipoprotein (LDL) oxidation. Difficulties in purifying PON1 from apolipoprotein A-I (apoA-I) suggested that PON1's association with HDL may occur through a direct binding between these 2 proteins. An unusual property of PON1 is that the mature protein retains its hydrophobic N-terminal signal sequence. By expressing in vitro a mutant PON1 with a cleavable N-terminus, we demonstrate that PON1 associates with lipoproteins through its N-terminus by binding phospholipids directly rather than binding apoA-I. Nonetheless, apoA-I stabilized arylesterase activity more than did phospholipid alone, apoA-II, or apoE. Consequently, we studied the role of apoA-I in PON1 expression and HDL association in mice genetically deficient in apoA-I. Though present in HDL fractions at decreased levels, PON1 arylesterase activity was less stable than in control mice. Furthermore, PON1 could be competitively removed from HDL by phospholipids, suggesting that PON1's retained N-terminal peptide allows transfer of the enzyme between phospholipid surfaces. Thus, our data suggest that PON1 is stabilized by apoA-I, and its binding to HDL and physiological distribution are dependent on the direct binding of the retained hydrophobic N-terminus to phospholipids optimally presented in association with apoA-I.
ESTHER : Sorenson_1999_Arterioscler.Thromb.Vasc.Biol_19_2214
PubMedSearch : Sorenson_1999_Arterioscler.Thromb.Vasc.Biol_19_2214
PubMedID: 10479665

Title : Paraoxonase active site required for protection against LDL oxidation involves its free sulfhydryl group and is different from that required for its arylesterase\/paraoxonase activities: selective action of human paraoxonase allozymes Q and R - Aviram_1998_Arterioscler.Thromb.Vasc.Biol_18_1617
Author(s) : Aviram M , Billecke S , Sorenson R , Bisgaier C , Newton R , Rosenblat M , Erogul J , Hsu C , Dunlop C , La Du BN
Ref : Arterioscler Thromb Vasc Biol , 18 :1617 , 1998
Abstract : Human serum paraoxonase (PON 1) exists in 2 major polymorphic forms (Q and R), which differ in the amino acid at position 191 (glutamine and arginine, respectively). These PON allozymes hydrolyze organophosphates and aromatic esters, and both also protect LDL from copper ion-induced oxidation. We have compared purified serum PONs of both forms and evaluated their effects on LDL oxidation, in respect to their arylesterase/paraoxonase activities. Copper ion-induced LDL oxidation, measured by the production of peroxides and aldehydes after 4 hours of incubation, were reduced up to 61% and 58%, respectively, by PON Q, but only up to 46% and 38%, respectively, by an equivalent concentration of PON R. These phenomena were PON-concentration dependent. Recombinant PON Q and PON R demonstrated similar patterns to that shown for the purified serum allozymes. PON Q and PON R differences in protection of LDL against oxidation were further evaluated in the presence of glutathione peroxidase (GPx). GPx (0.1 U/mL) alone reduced copper ion-induced LDL oxidation by 20% after 4 hours of incubation. The addition of PON R to the above system resulted in an additive inhibitory effect on LDL oxidation, whereas PON Q had no such additive effect. The 2 PON allozymes also differed by their ability to inhibit initiation, as well as propagation, of LDL oxidation. PON Q was more efficient in blocking LDL oxidation if added when oxidation was initiated, whereas PON R was more potent when added 1 hour after the initiation of LDL oxidation. These data suggest that the 2 allozymes act on different substrates. Both PON allozymes were also able to reduce the oxidation of phospholipids and cholesteryl ester. PON Q arylesterase activity was reduced after 4 hours of LDL oxidation by only 28%, whereas the arylesterase activity of PON R was reduced by up to 55%. Inactivation of the calcium-dependent PON arylesterase activity by using the metal chelator EDTA, or by calcium ion removal on a Chelex column, did not alter PON's ability to inhibit LDL oxidation. However, blockage of the PON free sulfhydryl group at position 283 with p-hydroxymercuribenzoate inhibited both its arylesterase activity and its protection of LDL from oxidation. Recombinant PON mutants in which the PON free sulfhydryl group was replaced by either alanine or serine were no longer able to protect against LDL oxidation, even though they retained paraoxonase and arylesterase activities. Overall, these studies demonstrate that PON's arylesterase/paraoxonase activities and the protection against LDL oxidation do not involve the active site on the enzyme in exactly the same way, and PON's ability to protect LDL from oxidation requires the cysteine residue at position 283.
ESTHER : Aviram_1998_Arterioscler.Thromb.Vasc.Biol_18_1617
PubMedSearch : Aviram_1998_Arterioscler.Thromb.Vasc.Biol_18_1617
PubMedID: 9763535

Title : LDL oxidation by arterial wall macrophages depends on the oxidative status in the lipoprotein and in the cells: role of prooxidants vs. antioxidants - Aviram_1998_Mol.Cell.Biochem_188_149
Author(s) : Aviram M , Fuhrman B
Ref : Molecular & Cellular Biochemistry , 188 :149 , 1998
Abstract : Oxidized LDL is highly atherogenic as it stimulates macrophage cholesterol accumulation and foam cell formation, it is cytotoxic to cells of the arterial wall and it stimulates inflammatory and thrombotic processes. LDL oxidation can lead to its subsequent aggregation, which further increases cellular cholesterol accumulation. All major cells in the arterial wall including endothelial cells, smooth muscle cells and monocyte derived macrophages can oxidize LDL. Macrophage-mediated oxidation of LDL is probably a hallmark in early atherosclerosis, and it depends on the oxidative state of the LDL and that of the macrophages. The LDL oxidative state is elevated by increased ratio of poly/mono unsaturated fatty acids, and it is reduced by elevation of LDL-associated antioxidants such as vitamin E, beta-carotene, lycopene, and polyphenolic flavonoids. The macrophage oxidative state depends on the balance between cellular NADPH-oxidase and the glutathione system. LDL-associated polyphenolic flavonoids which inhibit its oxidation, can also reduce macrophage oxidative state, and subsequently the cell-mediated oxidation of LDL. Oxidation of the macrophage lipids, which occurs under oxidative stress, can lead to cell-mediated oxidation of LDL even in the absence of transition metal ions, and may be operable in vivo. Finally, elimination of Ox-LDL from extracellular spaces, after it was formed under excessive oxidative stress, can possibly be achieved by the hydrolytic action of HDL-associated paraoxonase on lipoprotein's lipid peroxides. The present review article summarizes the above issues with an emphasis on our own data.
ESTHER : Aviram_1998_Mol.Cell.Biochem_188_149
PubMedSearch : Aviram_1998_Mol.Cell.Biochem_188_149
PubMedID: 9823020

Title : Atorvastatin and gemfibrozil metabolites, but not the parent drugs, are potent antioxidants against lipoprotein oxidation - Aviram_1998_Atherosclerosis_138_271
Author(s) : Aviram M , Rosenblat M , Bisgaier CL , Newton RS
Ref : Atherosclerosis , 138 :271 , 1998
Abstract : Increased atherosclerosis risk in hyperlipidemic patients may be a result of the enhanced oxidizability of their plasma lipoproteins. We have previously shown that hypocholesterolemic drug therapy, including the 3-hydroxy-3-methyl-glutaryl CoenzymeA (HMG-CoA) reductase inhibitors, and the hypotriglyceridemic drug bezafibrate, significantly reduced the enhanced susceptibility to oxidation of low density lipoprotein (LDL) isolated from hyperlipidemic patients. Although this antioxidative effect could not be obtained in vitro with all of these drugs, the active drug metabolites, which are formed in vivo, could affect lipoprotein oxidizability. We thus sought to analyze the effect of atorvastatin and gemfibrozil, as well as specific hydroxylated metabolites, on the susceptibility of LDL, very low density lipoprotein (VLDL), and high density lipoprotein (HDL) to oxidation. LDL oxidation induced by either copper ions (10 microM CuSO4), by the free radical generator system 2'-2'-azobis 2-amidino propane hydrochloride (5 mM AAPH), or by the J-774A.1 macrophage-like cell line, was not inhibited by the parent forms of atorvastatin or gemfibrozil, but was substantially inhibited (57-97%), in a concentration-dependent manner, by pharmacological concentrations of the o-hydroxy and the p-hydroxy metabolites of atorvastatin, as well as by the p-hydroxy metabolite (metabolite I) of gemfibrozil. On using the atorvastatin o-hydroxy metabolite and gemfibrozil metabolite I in combination an additive inhibitory effect on LDL oxidizability was found. Similar inhibitory effects (37-96%) of the above metabolites were obtained for the susceptibility of VLDL and HDL to oxidation in the oxidation systems outlined above. The inhibitory effects of these metabolites on LDL, VLDL, and HDL oxidation could be related to their free radical scavenging activity, as well as (mainly for the gemfibrozil metabolite I) to their metal ion chelation capacities. In addition, inhibition of HDL oxidation was associated with the preservation of HDL-associated paraoxonase activity. We conclude that atorvastatin hydroxy metabolites, and gemfibrozil metabolite I possess potent antioxidative potential, and as a result protect LDL, VLDL, and HDL from oxidation. We hypothesize that in addition to their beneficial lipid regulating activity, specific metabolites of both drugs may also reduce the atherogenic potential of lipoproteins through their antioxidant properties.
ESTHER : Aviram_1998_Atherosclerosis_138_271
PubMedSearch : Aviram_1998_Atherosclerosis_138_271
PubMedID: 9690910

Title : Paraoxonase inhibits high-density lipoprotein oxidation and preserves its functions. A possible peroxidative role for paraoxonase - Aviram_1998_J.Clin.Invest_101_1581
Author(s) : Aviram M , Rosenblat M , Bisgaier CL , Newton RS , Primo-Parmo SL , La Du BN
Ref : J Clinical Investigation , 101 :1581 , 1998
Abstract : HDL levels are inversely related to the risk of developing atherosclerosis. In serum, paraoxonase (PON) is associated with HDL, and was shown to inhibit LDL oxidation. Whether PON also protects HDL from oxidation is unknown, and was determined in the present study. In humans, we found serum HDL PON activity and HDL susceptibility to oxidation to be inversely correlated (r2 = 0.77, n = 15). Supplementing human HDL with purified PON inhibited copper-induced HDL oxidation in a concentration-dependent manner. Adding PON to HDL prolonged the oxidation lag phase and reduced HDL peroxide and aldehyde formation by up to 95%. This inhibitory effect was most pronounced when PON was added before oxidation initiation. When purified PON was added to whole serum, essentially all of it became HDL-associated. The PON-enriched HDL was more resistant to copper ion-induced oxidation than was control HDL. Compared with control HDL, HDL from PON-treated serum showed a 66% prolongation in the lag phase of its oxidation, and up to a 40% reduction in peroxide and aldehyde content. In contrast, in the presence of various PON inhibitors, HDL oxidation induced by either copper ions or by a free radical generating system was markedly enhanced. As PON inhibited HDL oxidation, two major functions of HDL were assessed: macrophage cholesterol efflux, and LDL protection from oxidation. Compared with oxidized untreated HDL, oxidized PON-treated HDL caused a 45% increase in cellular cholesterol efflux from J-774 A.1 macrophages. Both HDL-associated PON and purified PON were potent inhibitors of LDL oxidation. Searching for a possible mechanism for PON-induced inhibition of HDL oxidation revealed PON (2 paraoxonase U/ml)-mediated hydrolysis of lipid peroxides (by 19%) and of cholesteryl linoleate hydroperoxides (by 90%) in oxidized HDL. HDL-associated PON, as well as purified PON, were also able to substantially hydrolyze (up to 25%) hydrogen peroxide (H2O2), a major reactive oxygen species produced under oxidative stress during atherogenesis. Finally, we analyzed serum PON activity in the atherosclerotic apolipoprotein E-deficient mice during aging and development of atherosclerotic lesions. With age, serum lipid peroxidation and lesion size increased, whereas serum PON activity decreased. We thus conclude that HDL-associated PON possesses peroxidase-like activity that can contribute to the protective effect of PON against lipoprotein oxidation. The presence of PON in HDL may thus be a major contributor to the antiatherogenicity of this lipoprotein.
ESTHER : Aviram_1998_J.Clin.Invest_101_1581
PubMedSearch : Aviram_1998_J.Clin.Invest_101_1581
PubMedID: 9541487

Title : Reduced progression of atherosclerosis in apolipoprotein E-deficient mice following consumption of red wine, or its polyphenols quercetin or catechin, is associated with reduced susceptibility of LDL to oxidation and aggregation - Hayek_1997_Arterioscler.Thromb.Vasc.Biol_17_2744
Author(s) : Hayek T , Fuhrman B , Vaya J , Rosenblat M , Belinky P , Coleman R , Elis A , Aviram M
Ref : Arterioscler Thromb Vasc Biol , 17 :2744 , 1997
Abstract : The effect of consuming red wine, or its major polyphenol constituents catechin or quercetin, on the development of atherosclerotic lesions, in relation to the susceptibility of plasma LDL to oxidation and to aggregation, was studied in atherosclerotic apolipoprotein E deficient (E degree) mice. Forty E degree mice at the age of 4 weeks were divided into four groups, 10 mice in each group, and were supplemented for up to 6 weeks in their drinking water with placebo (1.1% alcohol); catechin or quercetin (50 micrograms/d per mouse), or red wine (0.5 mL/d per mouse). Consumption of catechin, quercetin, or red wine had no effect on plasma LDL or HDL cholesterol levels. The atherosclerotic lesion area was smaller in the treated mice by 39%, 46%, and 48%, respectively, in comparison with E degree mice that were treated with placebo. In accordance with these findings, cellular uptake of LDL derived after catechin, quercetin, or red wine consumption was found to be reduced by 31%, 40%, and 52%, respectively. These results were associated with reduced susceptibility to oxidation (induced by different modes such as copper ions, free radical generator, or macrophages) of LDL isolated after red wine or quercetin and, to a lesser extent after catechin consumption, in comparison with LDL isolated from the placebo group. Similar results were obtained when LDL was preincubated in vitro with red wine or with the polyphenols prior to its oxidation. Even in the basal oxidative state (not induced oxidation), LDL isolated from E degree mice that consumed catechin, quercetin, or red wine for 2 weeks was found to be less oxidized in comparison with LDL isolated from E degree mice that received placebo, as evidenced by 39%, 48%, and 49% reduced content of LDL-associated lipid peroxides, respectively. This effect could be related to enhanced serum paraoxonase activity in the polyphenol-treated mice. LDL oxidation was previously shown to lead to its aggregation. The present study demonstrated that the susceptibility of LDL to aggregation was reduced in comparison with placebo-treated mice, by 63%, 48%, or 50% by catechin, quercetin, and red wine consumption, respectively, and this effect could be shown also in vitro. The inhibition of LDL oxidation by polyphenols could be related, at least in part, to a direct effect of the polyphenols on the LDL, since both quercetin and catechin were found to bind to the LDL particle via the formation of an ether bond. We thus conclude that dietary consumption by E degree mice of red wine or its polyphenolic flavonoids quercetin and, to a lesser extent, catechin leads to attenuation in the development of the atherosclerotic lesion, and this effect is associated with reduced susceptibility of their LDL to oxidation and aggregation.
ESTHER : Hayek_1997_Arterioscler.Thromb.Vasc.Biol_17_2744
PubMedSearch : Hayek_1997_Arterioscler.Thromb.Vasc.Biol_17_2744
PubMedID: 9409251

Title : Modification of low density lipoprotein by lipoprotein lipase or hepatic lipase induces enhanced uptake and cholesterol accumulation in cells - Aviram_1988_J.Biol.Chem_263_15416
Author(s) : Aviram M , Bierman EL , Chait A
Ref : Journal of Biological Chemistry , 263 :15416 , 1988
Abstract : Incubation of low density lipoprotein(s) (LDL) with either lipoprotein lipase or hepatic lipase led to modification of the core lipid composition of LDL. Both lipases modified LDL by substantially reducing core triglyceride content without producing marked differences in size, charge, or lipid peroxide content in comparison to native LDL. The triglyceride-depleted forms of LDL that result from treatment with these two enzymes were degraded at approximately twice the rate of native LDL by human monocyte-derived macrophages (HMDM). Lipase-modified LDL degradation was inhibited by chloroquine, suggesting lysosomal involvement in LDL cellular processing. The increased degradation by macrophages of the LDL modified by these lipases was accompanied by enhanced cholesterol esterification rates, as well as by an increase in cellular free and esterified cholesterol content. In a patient with hepatic triglyceride lipase deficiency, degradation of the triglyceride-rich LDL by HMDM was approximately half that of normal LDL. Following in vitro incubation of LDL from this patient with either lipoprotein or hepatic lipase, lipoprotein degradation increased to normal. Several lines of evidence indicate that LDL modified by both lipases were taken up by the LDL receptor and not by the scavenger receptor. 1) The degradation of lipase-modified LDL in nonphagocytic cells (human skin fibroblast and arterial smooth muscle cells) as well as in phagocytic cells (HMDM, J-774, HL-60, and U-937 cell lines) could be dissociated from that of acetylated LDL and was always higher than that of native LDL. A similar pattern was found for cellular cholesterol esterification and cholesterol mass. 2) LDL receptor-negative fibroblasts did not degrade lipase-modified LDL. 3) A monoclonal antibody to the LDL receptor inhibited macrophage degradation of the lipase-modified LDL. 4) Excess amounts of unlabeled LDL competed substantially with 125I-labeled lipase-modified LDL for degradation by both macrophages and fibroblasts. Thus, lipase-modified LDL can cause significant cholesterol accumulation in macrophages even though it is taken up by LDL and not by the scavenger receptor. This effect could possibly be related to the reduced triglyceride content in the core of LDL, which may alter presentation of the LDL receptor-binding domain of apolipoprotein B on the particle surface, thereby leading to increased recognition and cellular uptake via the LDL receptor pathway.
ESTHER : Aviram_1988_J.Biol.Chem_263_15416
PubMedSearch : Aviram_1988_J.Biol.Chem_263_15416
PubMedID: 3170589