APOE4 Regulates Synaptic Function by Directly Modulating the SNARE Complex Assembly

Background: The ε4 allele of the Apolipoprotein E (APOE) gene is a major genetic risk determinant of sporadic Alzheimer's disease (AD). Its protein product APOE4 has been demonstrated to coffers deleterious effects for various neurodegenerative disorders related to cognitive impairment, including AD. A line of evidence implied that APOE4 affects these diseases partly through its synaptic damage. However, the mechanisms underlying this have not been fully interpreted.Methods: Proteomics analysis, Co-immunoprecipitation assay (Co-IP), Bimolecular fluorescence complementation (BIFC), and Proximity ligation assay (PLA) assays were used to screen and verify the interactome of APOE, which in an APOE4-priority manner. The molecular docking and molecular dynamic analysis were conducted to elucidate the molecular mechanisms that APOE3 differs from APOE4 in the binding ability of VAMP2. Adeno-associated virus expressing APOE3 and APOE4 was stereotaxically injected into the Hippocampus of Apoe-/- mice, and in vitro recombinant proteins experiments were conducted to verify the AOPE on soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex assemble. FM4-64 fluorescent dye labeling assay was explored in hippocampus from APOE3-TR and APOE4-TR mice to study the APOE genotype effect on synaptic vesicle release.Results:Using proteomics analysis, we screened interactomes of APOE3 and APOE4 in neurons, respectively. Then, VAMP2 protein was selected for further analysis through related bioinformatics analysis. Via Co-IP, BIFC, and PLA assays,we demonstrated that APOE directly interacts with VAMP2 in an E4 > E3 manner in vitro and in vivo. The molecular docking and molecular dynamic analysis suggested that the APOE4-VAMP2 complex was more stable and had higher affinity than APOE3-VAMP2, may due to the increased contribution of hydrogen bonding, hamper VAMP2 to form the SNARE complex. The further in vitro and in vivo results suggest that APOE4 blocks the SNARE complex assembly, negatively regulating synaptic vesicle release, finally contributing to the synaptic damage and cognitive impairment.Conclusions:Our findings identify SNARE protein as an APOE interactor, and APOE4 isoform effects on SNARE complex formation, mediates APOE4-induced synaptic dysfunction. Our results provide insights into APOE4-mediated synapse toxicity, and suggested new avenues for specifically targeting early presynaptic dysfunction in AD.

Phytochemical and Molecular Dynamic Analysis of Novel Biomolecule Lancifotarene Extracted From Conocarpus Lancifolius as Cytotoxic, Antiurease and Antidiabetic Agent

The authors have requested that this preprint be withdrawn due to erroneous posting.

In Silico Screening of the DrugBank Database to Search for Possible Drugs against SARS-CoV-2

Coronavirus desease 2019 (COVID-19) is responsible for more than 1.80 M deaths worldwide. A Quantitative Structure-Activity Relationships (QSAR) model is developed based on experimental pIC50 values reported for a structurally diverse dataset. A robust model with only five descriptors is found, with values of R2 = 0.897, Q2LOO = 0.854, and Q2ext = 0.876 and complying with all the parameters established in the validation Tropsha’s test. The analysis of the applicability domain (AD) reveals coverage of about 90% for the external test set. Docking and molecular dynamic analysis are performed on the three most relevant biological targets for SARS-CoV-2: main protease, papain-like protease, and RNA-dependent RNA polymerase. A screening of the DrugBank database is executed, predicting the pIC50 value of 6664 drugs, which are IN the AD of the model (coverage = 79%). Fifty-seven possible potent anti-COVID-19 candidates with pIC50 values > 6.6 are identified, and based on a pharmacophore modelling analysis, four compounds of this set can be suggested as potent candidates to be potential inhibitors of SARS-CoV-2. Finally, the biological activity of the compounds was related to the frontier molecular orbitals shapes.

Virtual Screening, Molecular Dynamics and ADME-Tox Tools for Finding Potential Inhibitors of Phosphoglycerate Mutase 1 from Plasmodium falciparum

Background: Nowadays, malaria is still one of the most important and lethal diseases worldwide, causing 445,000 deaths in a year. Due to the actual treatment resistance, there is an emergency to find new drugs. Objective: The aim of this work was to find potential inhibitors of phosphoglycerate mutase 1 from P. falciparum. Results: Through virtual screening of a chemical library of 15,123 small molecules, analyzed by two programs, four potential inhibitors of phosphoglycerate mutase 1 from P. falciparum were found: ZINC64219552, ZINC39095354, ZINC04593310, and ZINC04343691; their binding energies in SP mode were -7.3, -7.41, -7.4, and -7.18 kcal/mol respectively. Molecular dynamic analysis revealed that these molecules interact with residues important for enzyme catalysis and molecule ZINC04343691 provoked the highest structural changes. Physiochemical and toxicological profiles evaluation of these inhibitors with ADME-Tox method suggested that they can be considered as potential drugs. Furthermore, analysis of human PGAM-B suggested that these molecules could be selective for the parasitic enzyme. Conclusion: The compounds reported here are the first selective potential inhibitors of phosphoglycerate mutase 1 from P. falciparum, and can serve as a starting point in the search of a new chemotherapy against malaria.