Amara S

References (18)

Title : Prevention of neurotoxicity and cognitive impairment induced by zinc nanoparticles by oral administration of saffron extract - Hamdi_2023_J.Anim.Physiol.Anim.Nutr.(Berl)__
Author(s) : Hamdi E , Muniz-Gonzalez AB , Hidouri S , Bermejo AM , Sakly M , Venero C , Amara S
Ref : J Anim Physiol Anim Nutr (Berl) , : , 2023
Abstract : The accumulation of relatively higher dose of zinc oxide nanoparticles in brain was reported to produce neurotoxicity. Indeed, nanoparticles have a high ability to penetrate biological membranes and be uptaken by cells, which may cause cell disorders and physiological dysfunctions. The aim of the current study was to evaluate, whether oral administration of saffron extract, in rats, can protect from neurotoxicity and behavioural disturbances induced by chronic administration of ZnO-NPs. Daily oral administration of ZnO-NPs was performed for 21 consecutive days to induce oxidative stress-like situation. Then after the saffron extract was concomitantly administrated in several rat groups to overcome the nanotoxicological effect induced by ZnO-NPs. In the frontal cortex, the hippocampus and the cerebellum, ZnO-NPs induced a H(2) O(2) -oxydative stress-like effect reflected in reduced enzymatic activities of catalase, superoxide dismutase and glutathione S-transferase, and decreased acetylcholinesterase activity. In addition, increased levels of proinflammatory interleukins IL-6 and IL-1- occurred in the hippocampus, reveal the existence of brain inflammation. The concomitant administration of saffron extract to animals exposed to ZnO-NPs prevented the enhanced anxiety-related to the behaviour in the elevated plus-maze test, the open field test and preserved spatial learning abilities in the Morris water maze. Moreover, animals exposed to ZnO-NPs and saffron showed abnormal activity of several antioxidant enzymes as well as acetylcholinesterase activity, an effect that may underly the preserved anxiety-like behaviour and spatial learning abilities observed in these animals. Saffron extract has a potential beneficial therapeutic effect: antioxidant, anti-inflammatory and neuroprotective agent.
ESTHER : Hamdi_2023_J.Anim.Physiol.Anim.Nutr.(Berl)__
PubMedSearch : Hamdi_2023_J.Anim.Physiol.Anim.Nutr.(Berl)__
PubMedID: 37246965

Title : Quantitative monitoring of galactolipid hydrolysis by pancreatic lipase-related protein 2 using thin layer chromatography and thymol-sulfuric acid derivatization - Sahaka_2021_J.Chromatogr.B.Analyt.Technol.Biomed.Life.Sci_1173_122674
Author(s) : Sahaka M , Amara S , Lecomte J , Rodier JD , Lafont D , Villeneuve P , Gontero B , Carriere F
Ref : Journal of Chromatography B Analyt Technol Biomed Life Sciences , 1173 :122674 , 2021
Abstract : Galactolipids are the most abundant lipids on earth where they are mainly found in photosynthetic membranes of plant, algae, and cyanobacteria. Pancreatic lipase-related protein 2 (PLRP2) is an enzyme with galactolipase activity allowing mammals, especially herbivores, to digest this important source of fatty acids. We present a method for the quantitative analysis of galactolipids and galactosylated products resulting from their digestion by guinea pig PLRP2 (GPLRP2), using thin-layer-chromatography (TLC), thymol-sulfuric acid as derivatization reagent and scanning densitometry for detection. Thymol-sulfuric acid reagent has been used for the colorimetric detection of carbohydrates. It is shown here that the derivatization of galactosyl group from galactolipids by this reagent is not affected by the bound acyl glycerol, acyl chains length and number of galactose residues in the polar head. This allowed quantifying simultaneously the initial substrate and all galactosylated products generated upon the hydrolysis of monogalactosyl di-octanoylglycerol (C8-MGDG) by GPLRP2 using a single calibration with C8-MGDG as reference standard. The reaction products, monogalactosyl monooctanoyl glycerol (C8-MGMG) and monogalactosyl glycerol (MGG), were identified and quantified, MGG being recovered from the aqueous phase and analyzed by a separate TLC analysis. This method is therefore suitable to quantify the products resulting from the release of both fatty acids present in MGDG and thereby shows that PLRP2 can contribute to the complete digestion of galactolipids and further intestinal absorption of their fatty acids.
ESTHER : Sahaka_2021_J.Chromatogr.B.Analyt.Technol.Biomed.Life.Sci_1173_122674
PubMedSearch : Sahaka_2021_J.Chromatogr.B.Analyt.Technol.Biomed.Life.Sci_1173_122674
PubMedID: 33827017

Title : Characterization of all the lipolytic activities in pancreatin and comparison with porcine and human pancreatic juices - Salhi_2020_Biochimie_169_106
Author(s) : Salhi A , Amara S , Mansuelle P , Puppo R , Lebrun R , Gontero B , Aloulou A , Carriere F
Ref : Biochimie , 169 :106 , 2020
Abstract : Porcine pancreatic extracts (PPE), also named pancreatin, are commonly used as a global source of pancreatic enzymes for enzyme replacement therapy in patients with exocrine pancreatic insufficiency. They are considered as a good substitute of human pancreatic enzymes and they have become a material of choice for in vitro models of digestion. Nevertheless, while the global PPE contents in lipase, protease and amylase activities are well characterized, little is known about individual enzymes. Here we characterized the lipase, phospholipase, cholesterol esterase and galactolipase activities of PPE and compared them with those of porcine (PPJ) and human (HPJ) pancreatic juices. The phospholipase to lipase activity ratio was similar in PPJ and HPJ, but was 4-fold lower in PPE. The galactolipase and cholesterol esterase activities were found at lower levels in PPJ compared to HPJ, and they were further reduced in PPE. The enzymes known to display these activities in HPJ, pancreatic lipase-related protein 2 (PLRP2) and carboxylester hydrolase/bile salt-stimulated lipase (CEH/BSSL), were identified in PPJ using gel filtration experiments, SDS-PAGE and LC-MS/MS analysis. The galactolipase and cholesterol esterase activities of PPE indicated that PLRP2 and CEH/BSSL are still present at low levels in this enzyme preparation, but they were not detected by mass spectrometry. Besides differences between porcine and human enzymes, the lower levels of phospholipase, galactolipase and cholesterol esterase activities in PPE are probably due to some proteolysis occurring during the production process. In conclusion, PPE do not provide a full substitution of the lipolytic enzymes present in HPJ.
ESTHER : Salhi_2020_Biochimie_169_106
PubMedSearch : Salhi_2020_Biochimie_169_106
PubMedID: 31288050

Title : The digestion of galactolipids and its ubiquitous function in Nature for the uptake of the essential alpha-linolenic acid - Sahaka_2020_Food.Funct_11_6710
Author(s) : Sahaka M , Amara S , Wattanakul J , Gedi MA , Aldai N , Parsiegla G , Lecomte J , Christeller JT , Gray D , Gontero B , Villeneuve P , Carriere F
Ref : Food Funct , 11 :6710-6744 , 2020
Abstract : Galactolipids, mainly monogalactosyl diglycerides and digalactosyl diglycerides are the main lipids found in the membranes of plants, algae and photosynthetic microorganisms like microalgae and cyanobacteria. As such, they are the main lipids present at the surface of earth. They may represent up to 80% of the fatty acid stocks, including a large proportion of polyunsaturated fatty acids mainly alpha-linolenic acid (ALA). Nevertheless, the interest in these lipids for nutrition and other applications remains overlooked, probably because they are dispersed in the biomass and are not as easy to extract as vegetable oils from oleaginous fruit and oil seeds. Another reason is that galactolipids only represent a small fraction of the acylglycerolipids present in modern human diet. In herbivores such as horses, fish and folivorous insects, galactolipids may however represent the main source of dietary fatty acids due to their dietary habits and digestion physiology. The development of galactolipase assays has led to the identification and characterization of the enzymes involved in the digestion of galactolipids in the gastrointestinal tract, as well as by microorganisms. Pancreatic lipase-related protein 2 (PLRP2) has been identified as an important factor of galactolipid digestion in humans, together with pancreatic carboxyl ester hydrolase (CEH). The levels of PLRP2 are particularly high in monogastric herbivores thus highlighting the peculiar role of PLRP2 in the digestion of plant lipids. Similarly, pancreatic lipase homologs are found to be expressed in the midgut of folivorous insects, in which a high galactolipase activity can be measured. In fish, however, CEH is the main galactolipase involved. This review discusses the origins and fatty acid composition of galactolipids and the physiological contribution of galactolipid digestion in various species. This overlooked aspect of lipid digestion ensures not only the intake of ALA from its main natural source, but also the main lipid source of energy for growth of some herbivorous species.
ESTHER : Sahaka_2020_Food.Funct_11_6710
PubMedSearch : Sahaka_2020_Food.Funct_11_6710
PubMedID: 32687132
Gene_locus related to this paper: helam-a0a2w1b5z2 , cavpo-2plrp

Title : Galactolipase activity of Talaromyces thermophilus lipase on galactolipid micelles, monomolecular films and UV-absorbing surface-coated substrate - Belhaj_2018_Biochim.Biophys.Acta.Mol.Cell.Biol.Lipids_1863_1006
Author(s) : Belhaj I , Amara S , Parsiegla G , Sutto-Ortiz P , Sahaka M , Belghith H , Rousset A , Lafont D , Carriere F
Ref : Biochimica & Biophysica Acta Molecular & Cellular Biology Lipids , 1863 :1006 , 2018
Abstract : Talaromyces thermophilus lipase (TTL) was found to hydrolyze monogalactosyl diacylglycerol (MGDG) and digalactosyl diacylglycerol (DGDG) substrates presented in various forms to the enzyme. Different assay techniques were used for each substrate: pHstat with dioctanoyl galactolipid-bile salt mixed micelles, barostat with dilauroyl galactolipid monomolecular films spread at the air-water interface, and UV absorption using a novel MGDG substrate containing alpha-eleostearic acid as chromophore and coated on microtiter plates. The kinetic properties of TTL were compared to those of the homologous lipase from Thermomyces lanuginosus (TLL), guinea pig pancreatic lipase-related protein 2 and Fusarium solani cutinase. TTL was found to be the most active galactolipase, with a higher activity on micelles than on monomolecular films or surface-coated MGDG. Nevertheless, the UV absorption assay with coated MGDG was highly sensitive and allowed measuring significant activities with about 10ng of enzymes, against 100ng to 10mug with the pHstat. TTL showed longer lag times than TLL for reaching steady state kinetics of hydrolysis with monomolecular films or surface-coated MGDG. These findings and 3D-modelling of TTL based on the known structure of TLL pointed out to two phenylalanine to leucine substitutions in TTL, that could be responsible for its slower adsorption at lipid-water interface. TTL was found to be more active on MGDG than on DGDG using both galactolipid-bile salt mixed micelles and galactolipid monomolecular films. These later experiments suggest that the second galactose on galactolipid polar head impairs the enzyme adsorption on its aggregated substrate.
ESTHER : Belhaj_2018_Biochim.Biophys.Acta.Mol.Cell.Biol.Lipids_1863_1006
PubMedSearch : Belhaj_2018_Biochim.Biophys.Acta.Mol.Cell.Biol.Lipids_1863_1006
PubMedID: 29859246
Gene_locus related to this paper: talth-f6lqk7

Title : Aluminium oxide nanoparticles compromise spatial learning and memory performance in rats - M'Rad_2018_EXCLI.J_17_200
Author(s) : M'Rad I , Jeljeli M , Rihane N , Hilber P , Sakly M , Amara S
Ref : EXCLI J , 17 :200 , 2018
Abstract : Recently, the biosafety and potential influences of nanoparticles on central nervous system have received more attention. In the present study, we assessed the effect of aluminium oxide nanoparticles (Al2O3-NPs) on spatial cognition. Male Wistar rats were intravenously administered Al2O3-NP suspension (20 mg/kg body weight/day) for four consecutive days, after which they were assessed. The results indicated that Al2O3-NPs impaired spatial learning and memory ability. An increment in malondialdehyde levels with a concomitant decrease in superoxide dismutase activity confirmed the induction of oxidative stress in the hippocampus. Additionally, our findings showed that exposure to Al2O3-NPs resulted in decreased acetylcholinesterase activity in the hippocampus. Furthermore, Al2O3-NPs enhanced aluminium (Al) accumulation and disrupted mineral element homoeostasis in the hippocampus. However, they did not change the morphology of the hippocampus. Our results show a connection among oxidative stress, disruption of mineral element homoeostasis, and Al accumulation in the hippocampus, which leads to spatial memory deficit in rats treated with Al2O3-NPs.
ESTHER : M'Rad_2018_EXCLI.J_17_200
PubMedSearch : M'Rad_2018_EXCLI.J_17_200
PubMedID: 29743858

Title : Probing Conformational Changes and Interfacial Recognition Site of Lipases With Surfactants and Inhibitors - Mateos-Diaz_2017_Methods.Enzymol_583_279
Author(s) : Mateos-Diaz E , Amara S , Roussel A , Longhi S , Cambillau C , Carriere F
Ref : Methods Enzymol , 583 :279 , 2017
Abstract : Structural studies on lipases by X-ray crystallography have revealed conformational changes occurring in the presence of surfactants/inhibitors and the pivotal role played by a molecular "lid" of variable size and structure depending on the enzyme. Besides controlling the access to the enzyme active site, the lid is involved in lipase activation, formation of the interfacial recognition site (IRS), and substrate docking within the active site. The combined use of surfactants and inhibitors has been critical for a better understanding of lipase structure-function relationships. An overview of crystal structures of lipases in complex with surfactants and inhibitors reveals common structural features and shows how surfactants monomers interact with the lid in its open conformation. The location of surfactants, inhibitors, and hydrophobic residues exposed upon lid opening provides insights into the IRS of lipases. The mechanism by which surfactants promote the lid opening can be further investigated in solution by site-directed spin labeling of lipase coupled to electron paramagnetic resonance spectroscopy. These experimental approaches are illustrated here by results obtained with mammalian digestive lipases, fungal lipases, and cutinases.
ESTHER : Mateos-Diaz_2017_Methods.Enzymol_583_279
PubMedSearch : Mateos-Diaz_2017_Methods.Enzymol_583_279
PubMedID: 28063495

Title : Constitutive expression of human gastric lipase in Pichia pastoris and site-directed mutagenesis of key lid-stabilizing residues - Sams_2017_Biochim.Biophys.Acta_1862_1025
Author(s) : Sams L , Amara S , Chakroun A , Coudre S , Paume J , Giallo J , Carriere F
Ref : Biochimica & Biophysica Acta , 1862 :1025 , 2017
Abstract : The cDNA encoding human gastric lipase (HGL) was integrated into the genome of Pichia pastoris using the pGAPZalpha A transfer vector. The HGL signal peptide was replaced by the yeast alpha-factor to achieve an efficient secretion. Active rHGL was produced by the transformed yeast but its levels and stability were dependent on the pH. The highest activity was obtained upon buffering the culture medium at pH5, a condition that allowed preserving enzyme activity over time. A large fraction (72+/-2%) of secreted rHGL remained however bound to the yeast cells, and was released by washing the cell pellet with an acid glycine-HCl buffer (pH2.2). This procedure allowed establishing a first step of purification that was completed by size exclusion chromatography. N-terminal sequencing and MALDI-ToF mass spectrometry revealed that rHGL was produced in its mature form, with a global mass of 50,837+/-32Da corresponding to a N-glycosylated form of HGL polypeptide (43,193Da). rHGL activity was characterized as a function of pH, various substrates and in the presence of bile salts and pepsin, and was found similar to native HGL, except for slight changes in pH optima. We then studied by site-directed mutagenesis the role of three key residues (K4, E225, R229) involved in salt bridges stabilizing the lid domain that controls the access to the active site and is part of the interfacial recognition site. Their substitution has an impact on the pH-dependent activity of rHGL and its relative activities on medium and long chain triglycerides.
ESTHER : Sams_2017_Biochim.Biophys.Acta_1862_1025
PubMedSearch : Sams_2017_Biochim.Biophys.Acta_1862_1025
PubMedID: 28694218
Gene_locus related to this paper: human-LIPF

Title : The galactolipase activity of Fusarium solani (phospho)lipase - Jallouli_2015_Biochim.Biophys.Acta_1851_282
Author(s) : Jallouli R , Othman H , Amara S , Parsiegla G , Carriere F , Srairi-Abid N , Gargouri Y , Bezzine S
Ref : Biochimica & Biophysica Acta , 1851 :282 , 2015
Abstract : The purified (phospho)lipase of Fusarium solani (FSL), was known to be active on both triglycerides and phospholipids. This study aimed at assessing the potential of this enzyme in hydrolyzing galactolipids. FSL was found to hydrolyze at high rates of synthetic medium chains monogalactosyldiacylglycerol (4658+/-146U/mg on DiC8-MGDG) and digalactosyldiacylglycerol (3785+/-83U/mg on DiC8-DGDG) and natural long chain monogalactosyldiacylglycerol extracted from leek leaves (991+/-85U/mg). It is the microbial enzyme with the highest activity on galactolipids identified so far with a level of activity comparable to that of pancreatic lipase-related protein 2. FSL maximum activity on galactolipids was measured at pH8. The analysis of the hydrolysis product of natural MGDG from leek showed that FSL hydrolyzes preferentially the ester bond at the sn-1 position of galactolipids. To investigate the structure-activity relationships of FSL, a 3D model of this enzyme was built. In silico docking of medium chains MGDG and DGDG and phospholipid in the active site of FSL reveals structural solutions which are in concordance with in vitro tests.
ESTHER : Jallouli_2015_Biochim.Biophys.Acta_1851_282
PubMedSearch : Jallouli_2015_Biochim.Biophys.Acta_1851_282
PubMedID: 25529980
Gene_locus related to this paper: nech7-c7yuz1

Title : A Cutinase from Trichoderma reesei with a Lid-Covered Active Site and Kinetic Properties of True Lipases - Roussel_2014_J.Mol.Biol_426_3757
Author(s) : Roussel A , Amara S , Nyyssola A , Mateos-Diaz E , Blangy S , Kontkanen H , Westerholm-Parvinen A , Carriere F , Cambillau C
Ref : Journal of Molecular Biology , 426 :3757 , 2014
Abstract : Cutinases belong to the alpha/beta-hydrolase fold family of enzymes and degrade cutin and various esters, including triglycerides, phospholipids and galactolipids. Cutinases are able to degrade aggregated and soluble substrates because, in contrast with true lipases, they do not have a lid covering their catalytic machinery. We report here the structure of a cutinase from the fungus Trichoderma reesei (Tr) in native and inhibitor-bound conformations, along with its enzymatic characterization. A rare characteristic of Tr cutinase is its optimal activity at acidic pH. Furthermore, Tr cutinase, in contrast with classical cutinases, possesses a lid covering its active site and requires the presence of detergents for activity. In addition to the presence of the lid, the core of the Tr enzyme is very similar to other cutinase cores, with a central five-stranded beta-sheet covered by helices on either side. The catalytic residues form a catalytic triad involving Ser164, His229 and Asp216 that is covered by the two N-terminal helices, which form the lid. This lid opens in the presence of surfactants, such as beta-octylglucoside, and uncovers the catalytic crevice, allowing a C11Y4 phosphonate inhibitor to bind to the catalytic serine. Taken together, these results reveal Tr cutinase to be a member of a new group of lipolytic enzymes resembling cutinases but with kinetic and structural features of true lipases and a heightened specificity for long-chain triglycerides.
ESTHER : Roussel_2014_J.Mol.Biol_426_3757
PubMedSearch : Roussel_2014_J.Mol.Biol_426_3757
PubMedID: 25219509
Gene_locus related to this paper: hypjq-g0rh85

Title : Partial deletion of beta9 loop in pancreatic lipase-related protein 2 reduces enzyme activity with a larger effect on long acyl chain substrates - Dridi_2013_Biochim.Biophys.Acta_1831_1293
Author(s) : Dridi K , Amara S , Bezzine S , Rodriguez JA , Carriere F , Gaussier H
Ref : Biochimica & Biophysica Acta , 1831 :1293 , 2013
Abstract : Structural studies on pancreatic lipase have revealed a complex architecture of surface loops surrounding the enzyme active site and potentially involved in interactions with lipids. Two of them, the lid and beta loop, expose a large hydrophobic surface and are considered as acyl chain binding sites based on their interaction with an alkyl phosphonate inhibitor. While the role of the lid in substrate recognition and selectivity has been extensively studied, the implication of beta9 loop in acyl chain stabilization remained hypothetical. The characterization of an enzyme with a natural deletion of the lid, guinea pig pancreatic lipase-related protein 2 (GPLRP2), suggests however an essential contribution of the beta9 loop in the stabilization of the acyl enzyme intermediate formed during the lipolysis reaction. A GPLRP2 mutant with a seven-residue deletion of beta9 loop (GPLRP2-deltabeta9) was produced and its enzyme activity was measured using various substrates (triglycerides, monoglycerides, galactolipids, phospholipids, vinyl esters) with short, medium and long acyl chains. Whatever the substrate tested, GPLRP2-deltabeta9 activity is drastically reduced compared to that of wild-type GPLRP2 and this effect is more pronounced as the length of substrate acyl chain increases. Changes in relative substrate selectivity and stereoselectivity remained however weak. The deletion within beta9 loop has also a negative effect on the rate of enzyme inhibition by alkyl phosphonates. All these findings indicate that the reduced enzyme turnover observed with GPLRP2-deltabeta9 results from a weaker stabilization of the acyl enzyme intermediate due to a loss of hydrophobic interactions.
ESTHER : Dridi_2013_Biochim.Biophys.Acta_1831_1293
PubMedSearch : Dridi_2013_Biochim.Biophys.Acta_1831_1293
PubMedID: 24046870
Gene_locus related to this paper: human-PNLIPRP2

Title : The galactolipase activity of some microbial lipases and pancreatic enzymes - Amara_2013_Eur.J.Lipid.Sci.Technol_115_442
Author(s) : Amara S , Lafont D , Parsiegla G , Point V , Chabannes A , Rousset A , Carriere F
Ref : Eur J Lipid Sci Technol , 115 :442 , 2013
Abstract : Several well known microbial lipases were screened for their ability to hydrolyze synthetic medium chain monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG). Fusarium solani cutinase and Thermomyces lanuginosus lipase (TLL) were found to hydrolyze MGDG at high rates (984 +/- 62 and 450 +/-41 U/mg, respectively). These activities remained however lower than those measured with pancreatic lipase-related protein 2 (PLRP2) on the same substrate. As previously observed with PLRP2, galactolipid-bile salt mixed micelles were found to be the best substrate form for microbial enzymes. The galactolipid to bile salt molar ratios for measuring maximum galactolipase activities were found to be similar to those previously established with PLRP2, suggesting that bile salts have mainly an effect on the substrate and not on the enzyme itself. The galactolipase activity of cutinase and TLL, as well as human and guinea pig PLRP2s were also measured using galactolipid monomolecular films. Enzymes having a lid (TLL and human PLRP2) were found to act at higher surface pressures than those with no lid (cutinase and guinea pig PLRP2). In silico docking of medium chain MGDG and DGDG in the active site of guinea pig PLRP2 and TLL reveals some structural analogies between these enzymes
ESTHER : Amara_2013_Eur.J.Lipid.Sci.Technol_115_442
PubMedSearch : Amara_2013_Eur.J.Lipid.Sci.Technol_115_442
Gene_locus related to this paper: bovin-balip , human-CEL

Title : Inhibition of phospholipase A1, lipase and galactolipase activities of pancreatic lipase-related protein 2 by methyl arachidonyl fluorophosphonate (MAFP) - Amara_2012_Biochim.Biophys.Acta_1821_1379
Author(s) : Amara S , Delorme V , Record M , Carriere F
Ref : Biochimica & Biophysica Acta , 1821 :1379 , 2012
Abstract : Methyl arachidonyl fluorophosphonate (MAFP) is a known inhibitor of cytosolic phospholipase A2 and some other serine enzymes. MAFP was found here to be an irreversible inhibitor of human pancreatic lipase-related protein 2 (HPLRP2), an enzyme displaying lipase, phospholipase A1 and galactolipase activities. In the presence of MAFP, mass spectrometry analysis of HPLRP2 revealed a mass increase of 351Da, suggesting a covalent binding of MAFP to the active site serine residue. When HPLRP2 was pre-incubated with MAFP before measuring residual activity, a direct inhibition of HPLRP2 occurred, confirming that HPLRP2 has an active site freely accessible to solvent and differs from most lipases in solution. HPLRP2 activities on tributyrin (TC4), phosphatidylcholine (PC) and monogalactosyl dioctanoylglycerol (C8-MGDG) were equally inhibited under these conditions. Bile salts were not required to trigger the inhibition, but they significantly increased the rate of HPLRP2 inhibition, probably because of MAFP micellar solubilization. Since HPLRP2 is active on various substrates that self-organize differently in the presence of water, HPLRP2 inhibition by MAFP was tested in the presence of these substrates after adding MAFP in the course of the lipolysis reaction. In this case, the rates of inhibition of lipase, phospholipase A1 and galactolipase activities were not equivalent (triglycerides>PC>MGDG), suggesting different enzyme/inhibitor partitioning between the aqueous phase and lipid aggregates. The inhibition by MAFP of a well identified phospholipase A1 (HPLRP2), present in pancreatic juice and also in human monocytes, indicates that MAFP cannot be used for discriminating phospholipase A2 from A1 activities at the cellular level.
ESTHER : Amara_2012_Biochim.Biophys.Acta_1821_1379
PubMedSearch : Amara_2012_Biochim.Biophys.Acta_1821_1379
PubMedID: 22835523
Gene_locus related to this paper: human-PNLIPRP2

Title : Analysis of the discriminative inhibition of mammalian digestive lipases by 3-phenyl substituted 1,3,4-oxadiazol-2(3H)-ones. - Point_2012_Eur.J.Med.Chem_58_452
Author(s) : Point V , Pavan Kumar KV , Marc S , Delorme V , Parsiegla G , Amara S , Carriere F , Buono G , Fotiadu F , Canaan S , Leclaire J , Cavalier JF
Ref : Eur Journal of Medicinal Chemistry , 58 :452 , 2012
Abstract : We report here the reactivity and selectivity of three 5-Methoxy-N-3-Phenyl substituted-1,3,4-Oxadiazol-2(3H)-ones (MPOX, as well as meta and para-PhenoxyPhenyl derivatives, i.e.MmPPOX and MpPPOX) with respect to the inhibition of mammalian digestive lipases: dog gastric lipase (DGL), human (HPL) and porcine (PPL) pancreatic lipases, human (HPLRP2) and guinea pig (GPLRP2) pancreatic lipase-related proteins 2, human pancreatic carboxyl ester hydrolase (hCEH), and porcine pancreatic extracts (PPE). All three oxadiazolones displayed similar inhibitory activities on DGL, PLRP2s and hCEH than the FDA-approved anti-obesity drug Orlistat towards the same enzymes. These compounds appeared however to be discriminative of HPL (poorly inhibited) and PPL (fully inhibited). The inhibitory activities obtained experimentally in vitro were further rationalized using in silico molecular docking. In the case of DGL, we demonstrated that the phenoxy group plays a key role in specific molecular interactions within the lipase's active site. The absence of this group in the case of MPOX, as well as its connectivity to the neighbouring aromatic ring in the case of MmPPOX and MpPPOX, strongly impacts the inhibitory efficiency of these oxadiazolones and leads to a significant gain in selectivity towards the lipases tested. The powerful inhibition of PPL, DGL, PLRP2s, hCEH and to a lesser extend HPL, suggests that oxadiazolone derivatives could also provide useful leads for the development of novel and more discriminative inhibitors of digestive lipases. These inhibitors could be used for a better understanding of individual lipase function as well as for drug development aiming at the regulation of the whole gastrointestinal lipolysis process.
ESTHER : Point_2012_Eur.J.Med.Chem_58_452
PubMedSearch : Point_2012_Eur.J.Med.Chem_58_452
PubMedID: 23153815
Gene_locus related to this paper: canfa-1lipg , cavpo-2plrp , human-CEL , human-PNLIP , human-PNLIPRP2 , pig-1plip

Title : Bis (monoacylglycero) phosphate interfacial properties and lipolysis by pancreatic lipase-related protein 2, an enzyme present in THP-1 human monocytes - Record_2011_Biochim.Biophys.Acta_1811_419
Author(s) : Record M , Amara S , Subra C , Jiang G , Prestwich GD , Ferrato F , Carriere F
Ref : Biochimica & Biophysica Acta , 1811 :419 , 2011
Abstract : The interfacial physical properties of bis(monoacylglycero)phosphate (BMP) and its derivatives with three oleoyl chains (hemi-BDP) and four oleoyl chains (bis(diacylglycero)phosphate, BDP) were investigated using Langmuir monomolecular films. The mean molecular area of BMP at the collapse surface pressure (45mN m(-1)) was similar to those measured with other phospholipids bearing two acyl chains (66 and 59.6A(2) molecule(-1) at pH 5.5 and 8.0, respectively). In Hemi-BDP and BDP, the mean molecular area increased by 26 and 35A(2) molecule(-1) per additional acyl chain at pH 5.5 and 8.0, respectively. When BMP was added to a phospholipid mixture mimicking late endosome membrane composition at pH 8.0, the mean phospholipid molecular area increased by 7% regardless of the surface pressure. In contrast, the variation in molecular area was surface pressure-dependent at pH 5.5, a pH value close to that of intra-endosomal content. BMP and hemi-BDP, but not BDP, were hydrolyzed by pancreatic lipase-related protein 2 (PLRP2), which exhibits phospholipase A(1) activity. At pH 5.5, the maximum activities of PLRP2 on BMP were recorded at high surface pressures (25-35mN/m). At pH 8.0, the PLRP2 activity vs. surface pressure showed a bell-shaped curve with maximum activities at 15mN/m for both BMP and hemi-BDP. This is a new activity for this enzyme which could degrade cellular BMP since both human PLRP2 (HPLRP2) and BMP were localized in human monocytic THP-1 cells. This is the first report on the cellular localization of HPLRP2 in human monocytes.
ESTHER : Record_2011_Biochim.Biophys.Acta_1811_419
PubMedSearch : Record_2011_Biochim.Biophys.Acta_1811_419
PubMedID: 21554982

Title : Galactolipase, phospholipase and triacylglycerol lipase activities in the midgut of six species of lepidopteran larvae feeding on different lipid diets - Christeller_2011_J.Insect.Physiol_57_1232
Author(s) : Christeller JT , Amara S , Carriere F
Ref : J Insect Physiol , 57 :1232 , 2011
Abstract : Galactolipase, phospholipase and triacylglycerol lipase activities were measured from the midgut of six species of lepidopteran larvae, two folivores, Epiphyas postvittana (Tortricidae) and Helicoverpa armigera (Noctuidae); two granivores, Plodia interpunctella (Pyralidae) and Ephestia kuehniella (Pyrallidae); a presumptive carnivore, Galleria mellonella (Pyralidae); and a keratinophage, Tineola bisselliella (Tineidae). Galactolipase has not been previously reported in insects. Galactolipase and phospholipase activities were high in the folivores and triacylglycerol lipase activity was low, matching the high galactolipid content of leaves. Conversely, galactolipase and phospholipase activities were low, but not absent, and triacylglycerol lipase activity high in the four other non-folivorous species, matching the high acylglycerol content of their diets. These data suggest the utility of reclassification, for evolutionary studies, of phytophagous lepidoptera into two feeding classes; folivore and granivore, the latter having similarity to the fungivore line of feeders in terms of its lipase activities and ability to retrieve essential polyunsaturated long chain fatty acids from their diets. All the digestive lipases have alkaline pH optima for activity, matching the pH of the lepidopteran midgut and their amino acid content show modifications likely to stabilize the proteins in that environment.
ESTHER : Christeller_2011_J.Insect.Physiol_57_1232
PubMedSearch : Christeller_2011_J.Insect.Physiol_57_1232
PubMedID: 21704634

Title : Lipolysis of natural long chain and synthetic medium chain galactolipids by pancreatic lipase-related protein 2 - Amara_2010_Biochim.Biophys.Acta_1801_508
Author(s) : Amara S , Barouh N , Lecomte J , Lafont D , Robert S , Villeneuve P , de Caro A , Carriere F
Ref : Biochimica & Biophysica Acta , 1801 :508 , 2010
Abstract : Monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG) are the most abundant lipids in nature, mainly as important components of plant leaves and chloroplast membranes. Pancreatic lipase-related protein 2 (PLRP2) was previously found to express galactolipase activity, and it is assumed to be the main enzyme involved in the digestion of these common vegetable lipids in the gastrointestinal tract. Most of the previous in vitro studies were however performed with medium chain synthetic galactolipids as substrates. It was shown here that recombinant guinea pig (Cavia porcellus) as well as human PLRP2 hydrolyzed at high rates natural DGDG and MGDG extracted from spinach leaves. Their specific activities were estimated by combining the pH-stat technique, thin layer chromatography coupled to scanning densitometry and gas chromatography. The optimum assay conditions for hydrolysis of these natural long chain galactolipids were investigated and the optimum bile salt to substrate ratio was found to be different from that established with synthetic medium chains MGDG and DGDG. Nevertheless the length of acyl chains and the nature of the galactosyl polar head of the galactolipid did not have major effects on the specific activities of PLRP2, which were found to be very high on both medium chain [1786+/-100 to 5420+/-85U/mg] and long chain [1756+/-208 to 4167+/-167U/mg] galactolipids. Fatty acid composition analysis of natural MGDG, DGDG and their lipolysis products revealed that PLRP2 only hydrolyzed one ester bond at the sn-1 position of galactolipids. PLRP2 might be used to produce lipid and free fatty acid fractions enriched in either 16:3 n-3 or 18:3 n-3 fatty acids, both found at high levels in galactolipids.
ESTHER : Amara_2010_Biochim.Biophys.Acta_1801_508
PubMedSearch : Amara_2010_Biochim.Biophys.Acta_1801_508
PubMedID: 20083229
Gene_locus related to this paper: human-PNLIPRP2

Title : Continuous measurement of galactolipid hydrolysis by pancreatic lipolytic enzymes using the pH-stat technique and a medium chain monogalactosyl diglyceride as substrate - Amara_2009_Biochim.Biophys.Acta_1791_983
Author(s) : Amara S , Lafont D , Fiorentino B , Boullanger P , Carriere F , de Caro A
Ref : Biochimica & Biophysica Acta , 1791 :983 , 2009
Abstract : Galactolipids are the main lipids from plants and galactolipases play a major role in their metabolism. These enzymes were however poorly studied so far and only few assays have been developed. A specific and continuous galactolipase assay using synthetic medium chain monogalactosyl diacylglycerol (MGDG) as substrate was developed using the pH-stat technique and recombinant human (rHPLRP2) and guinea pig (rGPLRP2) pancreatic lipase-related protein 2 as model enzymes. PLRP2s are the main enzymes involved in the digestion of galactolipids in the gastrointestinal tract. Monogalactosyl di-octanoylglycerol was mixed with bile salt solutions by sonication to form a micellar substrate before launching the assay. The nature of the bile salt and the bile salt to MGDG ratio were found to significantly affect the rate of MGDG hydrolysis by rHPLRP2 and rGPLRP2. The maximum galactolipase activity of both enzymes was recorded with sodium deoxycholate (NaDC) and at a NaDC to MGDG ratio of 1.33 and at basic pH values (8.0-9.0). The maximum rates of hydrolysis were obtained using a MGDG concentration of 10(-2) M and calcium chloride was found to be not necessary to obtain the maximum of activity. Under these conditions, the maximum turnovers of rGPLRP2 and rHPLRP2 on mixed NaDC/MGDG micelles were found to be 8000+/-500 and 2800+/-60 micromol/min/mg (U/mg), respectively. These activities are in the same order of magnitude as the activities on triglycerides of lipases and they are the highest specific activities ever reported for galactolipases. For the sake of comparison, the hydrolysis of mixed bile salt/MGDG micelles was also tested using other pancreatic lipolytic enzymes and only native and recombinant human carboxyl ester hydrolase were found to display significant but lower activities (240+/-17 and 432+/-62 U/mg, respectively) on MGDG.
ESTHER : Amara_2009_Biochim.Biophys.Acta_1791_983
PubMedSearch : Amara_2009_Biochim.Biophys.Acta_1791_983
PubMedID: 19447192
Gene_locus related to this paper: cavpo-2plrp , human-PNLIPRP2