Title: Research progress on the protective mechanism of a novel soluble epoxide hydrolase inhibitor TPPU on ischemic stroke Huang P Ref: Front Neurol, 14:1083972, 2023 : PubMed
Arachidonic Acid (AA) is the precursor of cerebrovascular active substances in the human body, and its metabolites are closely associated with the pathogenesis of cerebrovascular diseases. In recent years, the cytochrome P450 (CYP) metabolic pathway of AA has become a research hotspot. Furthermore, the CYP metabolic pathway of AA is regulated by soluble epoxide hydrolase (sEH). 1-trifluoromethoxyphenyl-3(1-propionylpiperidin-4-yl) urea (TPPU) is a novel sEH inhibitor that exerts cerebrovascular protective activity. This article reviews the mechanism of TPPU's protective effect on ischemic stroke disease.
As natural functional bioactive ingredients found in foods and plants, polyphenols play various antioxidant and anti-inflammatory roles to prevent the development of disease and restore human health. The multi-target modulation of polyphenols provides a novel practical therapeutic strategy for neurodegenerative diseases that are difficult to treat with traditional drugs like glutathione and cholinesterase inhibitors. This review mainly focuses on the efficacy of polyphenols on ischemic stroke, Parkinson's disease and Alzheimer's disease, including in vivo and in vitro experimental studies. It is further emphasized that polyphenols exert neuroprotective effects primarily through inhibiting production of oxidative stress and inflammatory cytokines, which may be the underlying mechanism. However, polyphenols are still rarely used as medicines to treat neurodegenerative diseases. Due to the lack of clinical trials, the mechanism of polyphenols is still in the stage of insufficient exploration. Future large-scale multi-center randomized controlled trials and in-depth mechanism studies are still needed to fully assess the safety, efficacy and side effects of polyphenols.
Both strigolactones (SLs) and nitric oxide (NO) are regulatory signals with diverse roles during stress responses. At present, the interaction and mechanism of SLs and NO in tomato salt tolerance remain unclear. In the current study, tomato 'Micro-Tom' was used to study the roles and interactions of SLs and NO in salinity stress tolerance. The results show that 15 microM SLs synthetic analogs GR24 and 10 microM NO donor S-nitrosoglutathione (GSNO) promoted seedling growth under salt stress. TIS108 (an inhibitor of strigolactone synthesis) suppressed the positive roles of NO in tomato growth under salt stress, indicating that endogenous SLs might be involved in NO-induced salt response in tomato seedlings. Meanwhile, under salt stress, GSNO or GR24 treatment induced the increase of endogenous SLs content in tomato seedlings. Moreover, GR24 or GSNO treatment effectively increased the content of chlorophyll, carotenoids and ascorbic acid (ASA), and enhanced the activities of antioxidant enzymes (superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase), glutathione reductase (GR) and cleavage dioxygenase (CCD) enzyme. Additionally, GSNO or GR24 treatment also up-regulated the expression of SLs synthesis genes (SlCCD7, SlCCD8, SlD27 and SlMAX1) and its signal transduction genes (SlD14 and SlMAX2) in tomato seedlings under salt stress. While, a strigolactone synthesis inhibitor TIS108 blocked the increase of endogenous SLs, chlorophyll, carotenoids and ASA content, and antioxidant enzyme, GR, CCD enzyme activity and SLs-related gene expression levels induced by GSNO. Thus, SLs may play an important role in NO-enhanced salinity tolerance in tomato seedlings by increasing photosynthetic pigment content, enhancing antioxidant capacity and improving endogenous SLs synthesis.
Huperzine A (HupA) is a natural acetylcholinesterase inhibitor (AChEI) with the advantages of high efficiency, selectivity as well as reversibility and can exhibit significant therapeutic effects against certain neurodegenerative diseases. It is also beneficial in reducing the neurological impairment and neuroinflammation of experimental autoimmune encephalomyelitis (EAE), a classic model for multiple sclerosis (MS). However, whether HupA can directly regulate oligodendrocyte differentiation and maturation and promote remyelination has not been investigated previously. In this study, we have analyzed the potential protective effects of HupA on the demylination model of MS induced by cuprizone (CPZ). It was found that HupA significantly attenuated anxiety-like behavior, as well as augmented motor and cognitive functions in CPZ mice. It also decreased demyelination and axonal injury in CPZ mice. Moreover, in CPZ mice, HupA increased mRNA levels of the various anti-inflammatory cytokines (Arg1, CD206) while reducing the levels of different pro-inflammatory cytokines (iNOS, IL-1beta, IL-18, CD16, and TNF-alpha). Mecamylamine, a nicotinic acetylcholinergic receptor antagonist, could effectively reverse the effects of HupA. Therefore, we concluded that HupA primarily exerts its therapeutic effects on multiple sclerosis through alleviating demyelination and neuroinflammation.
Title: Early Use of Blood Purification in Severe Epstein-Barr Virus-Associated Hemophagocytic Syndrome Huang P, Huang C, Xu H, Lu J, Tian R, Wang Z, Chen Y Ref: Pediatrics, :, 2020 : PubMed
Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis (EBV-HLH) is a common type of hemophagocytic lymphohistiocytosis (HLH) that exhibits high rates of morbidity and fatalities. Multiorgan failure caused by Epstein-Barr virus (EBV)-induced hypercytokinemia is one of the main reasons for early deaths. Blood purification techniques have been successfully applied in previously treated hypercytokinemia. However, there were insufficient studies to support the combination of plasma exchange (PE) and continuous renal replacement therapy (CRRT) in treating patients with severe EBV-HLH. In this article, we have summarized the effects of early incorporation of PE and CRRT, together with HLH-2004 chemoimmunotherapy, in 8 pediatric patients with severe EBV-HLH. Early use of PE and CRRT appeared to be well tolerated, and no serious side effects and early deaths were observed. After PE and CRRT procedures, cytokine levels were reduced to normal values, except for soluble interleukin 2 receptor, and significant reductions in EBV DNA, serum ferritin, aspartate transaminase, total bilirubin, total bile acid, lactate dehydrogenase, and body temperature values and increases in the neutrophil count in addition to hemoglobin, albumin, and cholinesterase values were observed. Furthermore, through continuous HLH-2004 treatment regimens, lower limits of detection were exhibited for EBV DNA levels, and all other observational indicator levels were restored to normal. Finally, 7 patients achieved and maintained complete remission for 15 to 24 months, culminating in August 2019. Therefore, it is our suggestion that early incorporation of PE and CRRT with chemoimmunotherapy might be a safe and effective treatment for patients with severe EBV-HLH.
The ability to directly measure acetylcholine (ACh) release is an essential step toward understanding its physiological function. Here we optimized the GRAB(ACh) (GPCR-activation-based ACh) sensor to achieve substantially improved sensitivity in ACh detection, as well as reduced downstream coupling to intracellular pathways. The improved version of the ACh sensor retains the subsecond response kinetics, physiologically relevant affinity and precise molecular specificity for ACh of its predecessor. Using this sensor, we revealed compartmental ACh signals in the olfactory center of transgenic flies in response to external stimuli including odor and body shock. Using fiber photometry recording and two-photon imaging, our ACh sensor also enabled sensitive detection of single-trial ACh dynamics in multiple brain regions in mice performing a variety of behaviors.
Clethodim is one of the most widely used herbicides in agriculture, however, its potential toxic effects on organisms and the underlying toxicity mechanism are still poorly understood. In this study, zebrafish embryos at 6h post-fertilization (hpf) were exposed to 10mg/L, 20mg/L, and 30mg/L clethodim for up to 24 hpf, and zebrafish larvae at 6 days post-fertilization (dpf) were exposed to the same density gradient for 24h. Our results showed that clethodim could cause head and cardiovascular malformations in embryos: blurred brain ventricles, unapparent brain regions, condensation of nucleus and cytoplasm in brain cells, increased intercellular space, developmental malformations of eyes and ears, reduced neonatal neurons, disorder migration of neural ridge cells; morphological aberrations of the vascular ICM, slowing of heart beat and blood flow, reduction of circulating red blood cells, and delayed development of head and tail blood vessels. These defects could be a result of clethodim-induced oxidative stress and decreased acetylcholinesterase (AChE) activity, which in turn affected the expression of neurodevelopmental genes, decreased ATPase activity, and ultimately led to developmental malformations. The swimming behaviour of zebrafish larvae was observed to decrease with increasing concentration of clethodim exposure, but the angular velocity and mobility increased. These could be due to reduced AChE activity and disturbed gene expression of GABA, dopamine and glutamatergic neurotransmitter systems, which thus altered the locomotor behaviour. In summary, we found that clethodim induces developmental toxicity and neurotoxicity in zebrafish embryos and larvae.
The overuse of antibiotics in animal agriculture and medicine has caused a series of potential threats to public health. Macleaya cordata is a medicinal plant species from the Papaveraceae family, providing a safe resource for the manufacture of antimicrobial feed additive for livestock. The active constituents from M. cordata are known to include benzylisoquinoline alkaloids (BIAs) such as sanguinarine (SAN) and chelerythrine (CHE), but their metabolic pathways have yet to be studied in this non-model plant. The active biosynthesis of SAN and CHE in M. cordata was first examined and confirmed by feeding (13)C-labeled tyrosine. To gain further insights, we de novo sequenced the whole genome of M. cordata, the first to be sequenced from the Papaveraceae family. The M. cordata genome covering 378 Mb encodes 22,328 predicted protein-coding genes with 43.5% being transposable elements. As a member of basal eudicot, M. cordata genome lacks the paleohexaploidy event that occurred in almost all eudicots. From the genomics data, a complete set of 16 metabolic genes for SAN and CHE biosynthesis was retrieved, and 14 of their biochemical activities were validated. These genomics and metabolic data show the conserved BIA metabolic pathways in M. cordata and provide the knowledge foundation for future productions of SAN and CHE by crop improvement or microbial pathway reconstruction.
Title: Large-Scale First-Principles Molecular Dynamics Simulations with Electrostatic Embedding: Application to Acetylcholinesterase Catalysis Fattebert JL, Lau EY, Bennion BJ, Huang P, Lightstone FC Ref: J Chem Theory Comput, 11:5688, 2015 : PubMed
Enzymes are complicated solvated systems that typically require many atoms to simulate their function with any degree of accuracy. We have recently developed numerical techniques for large scale first-principles molecular dynamics simulations and applied them to the study of the enzymatic reaction catalyzed by acetylcholinesterase. We carried out density functional theory calculations for a quantum-mechanical (QM) subsystem consisting of 612 atoms with an O(N) complexity finite-difference approach. The QM subsystem is embedded inside an external potential field representing the electrostatic effect due to the environment. We obtained finite-temperature sampling by first-principles molecular dynamics for the acylation reaction of acetylcholine catalyzed by acetylcholinesterase. Our calculations show two energy barriers along the reaction coordinate for the enzyme-catalyzed acylation of acetylcholine. The second barrier (8.5 kcal/mol) is rate-limiting for the acylation reaction and in good agreement with experiment.
Traditional chemical weapon agents (CWAs) are known to bind acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). Their lethality is known to be different for different mammalian species. We have modeled the binding affinity of CWAs to AChE and BuChE in human, rabbit, rat and mouse using molecular docking and free energy calculations. Through molecular docking we are able to correctly bind the CWAs at the active site. Using molecular mechanics generalized Born surface area (MMGBSA) calculations, we determined the binding free energy in the active site. Through these calculations, we observe that correct orientation at the active site is critical to binding.
Uncompetitive N-methyl-d-aspartate (NMDA) receptor antagonists with fast off-rate (UFO) may represent promising drug candidates for various neurodegenerative disorders. In this study, we report that bis(propyl)-cognitin, a novel dimeric acetylcholinesterase inhibitor and gamma-aminobutyric acid subtype A receptor antagonist, is such an antagonist of NMDA receptors. In cultured rat hippocampal neurons, we demonstrated that bis(propyl)-cognitin voltage-dependently, selectively, and moderately inhibited NMDA-activated currents. The inhibitory effects of bis(propyl)-cognitin increased with the rise in NMDA and glycine concentrations. Kinetics analysis showed that the inhibition was of fast onset and offset with an off-rate time constant of 1.9 s. Molecular docking simulations showed moderate hydrophobic interaction between bis(propyl)-cognitin and the MK-801 binding region in the ion channel pore of the NMDA receptor. Bis(propyl)-cognitin was further found to compete with [(3)H]MK-801 with a K(i) value of 0.27 mum, and the mutation of NR1(N616R) significantly reduced its inhibitory potency. Under glutamate-mediated pathological conditions, bis(propyl)-cognitin, in contrast to bis(heptyl)-cognitin, prevented excitotoxicity with increasing effectiveness against escalating levels of glutamate and much more effectively protected against middle cerebral artery occlusion-induced brain damage than did memantine. More interestingly, under NMDA receptor-mediated physiological conditions, bis(propyl)-cognitin enhanced long-term potentiation in hippocampal slices, whereas MK-801 reduced and memantine did not alter this process. These results suggest that bis(propyl)-cognitin is a UFO antagonist of NMDA receptors with moderate affinity, which may provide a pathologically activated therapy for various neurodegenerative disorders associated with NMDA receptor dysregulation.
Title: [Comparison of curative effect of low flow rate plasma exchange combined with hemofiltration for treatment of liver failure] Yang YF, Huang P, Zhang N, Gai XD, Feng XN, Zhong YD, Wang LR, Yang YJ, Zhao W Ref: Zhongguo Wei Zhong Bing Ji Jiu Yi Xue, 21:111, 2009 : PubMed
OBJECTIVE: To investigate the effect of plasma exchange (PE) combined with hemofiltration (HF) on liver failure. METHODS: Seventy-seven inpatients with liver failure admitted during January 2006 to August 2007 were randomly assigned to receive PE combined with HF (PE+HF group, 38 cases), or PE alone (PE group, 39 cases). Forty-one inpatients with liver failure who had not received artificial liver support treatment were assigned to serve as control group. The survival rates and biochemical parameters of three groups were compared. RESULTS: There was no significant difference in biochemical parameters before treatment among three groups. Compared with pre-treatment values, albumin (Alb), cholinesterase (ChE) and prothrombin activity (PTA) of both PE group and PE+HF group were significantly increased after treatment, and total bilirubin (TBIL), alanine transaminase (ALT), aspartate transaminase (AST) of both PE group and PE+HF group were significantly decreased after treatment (P<0.05 or P<0.01). The survival rate of PE group, PE+HF group and control group was 48.7% (19/39), 68.4% (26/38), and 29.3% (12/41) respectively. The survival rate of PE+HF group was significantly higher than that of control group (chi(2)=12.11, P<0.01). The rate of recovery of consciousness of patients with hepatic encephalopathy in PE+HF group was higher than that of PE group (42.8% vs. 0, P<0.05). Compared with PE alone, the result was better when it was combined with HF in correction of electrolyte disturbance and acid-base imbalance (19/23 vs. 0/21, P<0.05). CONCLUSION: Treatment of liver failure by PE combined with HF is safe and effective, and its efficacy is higher than PE alone.
Genomics provides an unprecedented opportunity to probe in minute detail into the genomes of the world's most deadly pathogenic bacteria- Yersinia pestis. Here we report the complete genome sequence of Y. pestis strain 91001, a human-avirulent strain isolated from the rodent Brandt's vole-Microtus brandti. The genome of strain 91001 consists of one chromosome and four plasmids (pPCP1, pCD1, pMT1 and pCRY). The 9609-bp pPCP1 plasmid of strain 91001 is almost identical to the counterparts from reference strains (CO92 and KIM). There are 98 genes in the 70,159-bp range of plasmid pCD1. The 106,642-bp plasmid pMT1 has slightly different architecture compared with the reference ones. pCRY is a novel plasmid discovered in this work. It is 21,742 bp long and harbors a cryptic type IV secretory system. The chromosome of 91001 is 4,595,065 bp in length. Among the 4037 predicted genes, 141 are possible pseudo-genes. Due to the rearrangements mediated by insertion elements, the structure of the 91001 chromosome shows dramatic differences compared with CO92 and KIM. Based on the analysis of plasmids and chromosome architectures, pseudogene distribution, nitrate reduction negative mechanism and gene comparison, we conclude that strain 91001 and other strains isolated from M. brandti might have evolved from ancestral Y. pestis in a different lineage. The large genome fragment deletions in the 91001 chromosome and some pseudogenes may contribute to its unique nonpathogenicity to humans and host-specificity.
Yersinia pestis has been historically divided into three biovars: antiqua, mediaevalis, and orientalis. On the basis of this study, strains from Microtus-related plague foci are proposed to constitute a new biovar, microtus. Based on the ability to ferment glycerol and arabinose and to reduce nitrate, Y. pestis strains can be assigned to one of four biovars: antiqua (glycerol positive, arabinose positive, and nitrate positive), mediaevalis (glycerol positive, arabinose positive, and nitrate negative), orientalis (glycerol negative, arabinose positive, and nitrate positive), and microtus (glycerol positive, arabinose negative, and nitrate negative). A 93-bp in-frame deletion in glpD gene results in the glycerol-negative characteristic of biovar orientalis strains. Two kinds of point mutations in the napA gene may cause the nitrate reduction-negative characteristic in biovars mediaevalis and microtus, respectively. A 122-bp frameshift deletion in the araC gene may lead to the arabinose-negative phenotype of biovar microtus strains. Biovar microtus strains have a unique genomic profile of gene loss and pseudogene distribution, which most likely accounts for the human attenuation of this new biovar. Focused, hypothesis-based investigations on these specific genes will help delineate the determinants that enable this deadly pathogen to be virulent to humans and give insight into the evolution of Y. pestis and plague pathogenesis. Moreover, there may be the implications for development of biovar microtus strains as a potential vaccine.
Analogs of A-98593 (1) and its enantiomer ABT-594 (2) with diverse substituents on the pyridine ring were prepared and tested for affinity to nicotinic acetylcholine receptor binding sites in rat brain and for analgesic activity in the mouse hot plate assay. Numerous types of modifications were consistent with high affinity for [3H]cytisine binding sites. By contrast, only selected modifications resulted in retention of analgesic potency in the same range as 1 and 2. Analogs of 2 with one or two methyl substituents at the 3-position of the azetidine ring also were prepared and found to be substantially less active in both assays.
