Human Furin Research Articles

The kpc-1 3'UTR facilitates dendritic transport and translation efficiency of mRNAs for dendrite arborization of a mechanosensory neuron important for male courtship.

A recently reported Schizophrenia-associated genetic variant in the 3'UTR of the human furin gene, a homolog of C. elegans kpc-1, highlights an important role of the furin 3'UTR in neuronal development. We isolate three kpc-1 mutants that display abnormal dendrite arborization in PVD neurons and defective male mating behaviors. We show that the kpc-1 3'UTR participates in dendrite branching and self-avoidance. The kpc-1 3'UTR facilitates mRNA localization to branching points and contact points between sibling dendrites and promotes translation efficiency. A predicted secondary structural motif in the kpc-1 3'UTR is required for dendrite self-avoidance. Animals with over-expression of DMA-1, a PVD dendrite receptor, exhibit similar dendrite branching and self-avoidance defects that are suppressed with kpc-1 over-expression. Our results support a model in which KPC-1 proteins are synthesized at branching points and contact points to locally down-regulate DMA-1 receptors to promote dendrite branching and self-avoidance of a mechanosensory neuron important for male courtship.

Docking, MD Simulations, and DFT Calculations: Assessing W254's Function and Sartan Binding in Furin.

Furins are serine endoproteases that are involved in many biological processes, where they play important roles in normal metabolism, in the activation of various pathogens, while they are a target for therapeutic intervention. Dichlorophenyl-pyridine "BOS" compounds are well known drugs that are used as inhibitors of human furin by an induced-fit mechanism, in which tryptophan W254 in the furin catalytic cleft acts as a molecular transition energy gate. The binding of "BOS" drug into the active center of furin has been computationally studied using the density functional theory (DFT) and ONIOM multiscaling methodologies. The binding enthalpies of the W254 with the furin-BOS is -32.8 kcal/mol ("open") and -18.8 kcal/mol ("closed"), while the calculated torsion barrier was found at 30 kcal/mol. It is significantly smaller than the value of previous MD calculations due to the relaxation of the environment, i.e., nearby groups of the W254, leading to the reduction of the energy demands. The significant lower barrier explains the experimental finding that the dihedral barrier of W254 is overcome. Furthermore, sartans were studied to evaluate their potential as furin inhibitors. Sartans are AT1 antagonists, and they effectively inhibit the hypertensive effects induced by the peptide hormone Angiotensin II. Here, they have been docked into the cavity to evaluate their effect on the BOS ligand via docking and molecular dynamics simulations. A consistent binding of sartans within the cavity during the simulation was found, suggesting that they could act as furin inhibitors. Finally, sartans interact with the same amino acids as W254, leading to a competitive binding that may influence the pharmacological efficacy and potential drug interactions of sartans.

Large-scale synthesis of CISe/ZnS core-shell quantum dots and its effects on the enzymatic activity of recombinant human furin (an activator of SARS-COV-2 S1/S2 spike proteins)

We herein report, for the first time, the activity of copper indium selenide/zinc sulphide core-shell quantum dots (CISe/ZnS QDs) as an inhibitor against recombinant human furin, an enzyme that has been implicated in the aetiology of many diseases, including Covid-19. The cell viability of the as-synthesised CISe/ZnS QDs was tested against mouse colon carcinoma cells (C26), while the Furin activity was measured by hydrolysis of peptide substrate Pyr-RTKR-AMC liberating the fluorogenic 7-amino-4-methyl coumarin. The result showed that the as-synthesised stable near-infrared emitting (840 nm) CISe-ZnS QDs is biocompatible against C26 and can inhibit furin with an inhibition constant, Ki, of 15.66 μM. The IC50 was 11.29 ± 0.54 μM, while the enzymatic activity was abolished at about 23 μM of the inhibitor concentration. The results indicate the chemotherapeutic potential of CISe-ZnS QDs as an enzyme inhibitor, which may find application in managing diseases whose pathogenesis involves hyperactivity of furin.

Structural insights into the effect of mutations in the spike protein of SARS-CoV-2 on the binding with human furin protein

The SARS COV-2 and its variants are spreading around the world at an alarming speed, due to its higher transmissibility and the conformational changes caused by mutations. The resulting COVID-19 pandemic has imposed severe health consequences on human health. Several countries of the world including Pakistan have studied its genome extensively and provided productive findings. In the current study, the mCSM, DynaMut2, and I-Mutant servers were used to analyze the effect of identified mutations on the structural stability of spike protein however, the molecular docking and simulations approaches were used to evaluate the dynamics of the bonding network between the wild-type and mutant spike proteins with furin. We addressed the mutational modifications that have occurred in the spike protein of SARS-COV-2 that were found in 215 Pakistani's isolates of COVID-19 patients to study the influence of mutations on the stability of the protein and its interaction with the host cell. We found 7 single amino acid substitute mutations in various domains that reside in spike protein. The H49Y, N74K, G181V, and G446V were found in the S1 domain while the D614A, V622F, and Q677H mutations were found in the central helices of the spike protein. Based on the observation, G181V, G446V, D614A, and V622F mutants were found highly destabilizing and responsible for structural perturbation. Protein-protein docking and molecular simulation analysis with that of furin have predicted that all the mutants enhanced the binding efficiency however, the V622F mutant has greatly altered the binding capacity which is further verified by the KD value (7.1 E−14) and therefore may enhance the spike protein cleavage by Furin and increase the rate of infectivity by SARS-CoV-2. On the other hand, the total binding energy for each complex was calculated which revealed −50.57 kcal/mol for the wild type, for G181V −52.69 kcal/mol, for G446V −56.44 kcal/mol, for D614A −59.78 kcal/mol while for V622F the TBE was calculated to be −85.84 kcal/mol. Overall, the current finding shows that these mutations have increased the binding of Furin for spike protein and shows that D614A and V622F have significant effects on the binding and infectivity.

SARS-CoV-2 S Mutations: A Lesson from the Viral World to Understand How Human Furin Works.

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is the etiological agent responsible for the worldwide pandemic and has now claimed millions of lives. The virus combines several unusual characteristics and an extraordinary ability to spread among humans. In particular, the dependence of the maturation of the envelope glycoprotein S from Furin enables the invasion and replication of the virus virtually within the entire body, since this cellular protease is ubiquitously expressed. Here, we analyzed the naturally occurring variation of the amino acids sequence around the cleavage site of S. We found that the virus grossly mutates preferentially at P positions, resulting in single residue replacements that associate with gain-of-function phenotypes in specific conditions. Interestingly, some combinations of amino acids are absent, despite the evidence supporting some cleavability of the respective synthetic surrogates. In any case, the polybasic signature is maintained and, as a consequence, Furin dependence is preserved. Thus, no escape variants to Furin are observed in the population. Overall, the SARS-CoV-2 system per se represents an outstanding example of the evolution of substrate-enzyme interaction, demonstrating a fast-tracked optimization of a protein stretch towards the Furin catalytic pocket. Ultimately, these data disclose important information for the development of drugs targeting Furin and Furin-dependent pathogens.

W254 in furin functions as a molecular gate promoting anti-viral drug binding: Elucidation of putative drug tunneling and docking by non-equilibrium molecular dynamics

Furins are serine endoproteases that process precursor proteins into their biologically active forms, and they play essential roles in normal metabolism and disease presentation, including promoting expression of bacterial virulence factors and viral pathogenesis. Thus, furins represent vital targets for development of antimicrobial and antiviral therapeutics. Recent experimental evidence indicated that dichlorophenyl (DCP)-pyridine “BOS” drugs (e.g., BOS-318) competitively inhibit human furin by an induced-fit mechanism in which tryptophan W254 in the furin catalytic cleft (FCC) functions as a molecular gate, rotating nearly 180o through a steep energy barrier about its chi-1 dihedral to an “open” orientation, exposing a buried (i.e., cryptic) hydrophobic pocket 1. Once exposed, the non-polar DCP group of BOS-318, and similar halo-phenyl groups of analogs, enter the cryptic pocket, stabilizing drug binding. Here, we demonstrate flexible-receptor docking of BOS-318 (and various analogs) was unable to emulate the induced-fit motif, even when tryptophan was replaced with less bulky phenylalanine or glycine. While either substitution allowed access to the hydrophobic pocket for most ligands tested, optimal binding was observed only for W254, inferring a stabilizing effect of the indole sidechain. Furthermore, non-equilibrium steered molecular dynamics (sMD) in which the bound drugs (or their fragments) were extracted from the FCC did not cause closure of the open W254 gate, consistent with the thermodynamic stability of the open or closed W254 orientations. Finally, interactive molecular dynamics (iMD) revealed two putative conduits of drug entry and binding into the FCC, each coupled with W254 dihedral rotation and opening of the cryptic pocket. The iMD simulations further revealed ligand entry and binding in the FCC is likely driven in part by energy fluxes stemming from disruption and re-formation of ligand and protein solvation shells during drug migration from the solution phase into the FCC.

Consensus docking and MM-PBSA computations identify putative furin protease inhibitors for developing potential therapeutics against COVID-19.

The coronavirus disease 2019 (COVID-19) is a pandemic that has severely posed substantial health challenges and claimed millions of lives. Though vaccines have been produced to stem the spread of this disease, the death rate remains high since drugs used for treatment have therapeutic challenges. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes the disease, has a slew of potential therapeutic targets. Among them is the furin protease, which has a cleavage site on the virus’s spike protein. The cleavage site facilitates the entry of the virus into human cells via cell–cell fusion. This critical involvement of furin in the disease pathogenicity has made it a viable therapeutic strategy against the virus. This study employs the consensus docking approach using HYBRID and AutoDock Vina to virtually screen a pre-filtered library of 3942 natural product compounds of African origin against the human furin protease (PDB: 4RYD). Twenty of these compounds were selected as hits after meeting molecular docking cut-off of − 7 kcal.mol−1, pose alignment inspection, and having favorable furin-ligand interactions. An area under the curve (AUC) value of 0.72 was computed from the receiver operator characteristic (ROC) curve, and Boltzmann-enhanced discrimination of the ROC curve (BEDROC) value of 0.65 showed that AutoDock Vina was a reasonable tool for selecting actives for this target. Seven of these hits were proposed as potential leads having had bonding interactions with catalytic triad residues Ser368, His194, and Asp153, and other essential residues in the active site with plausible binding free energies between − 189 and − 95 kJ/mol from the Molecular Mechanics Poisson-Boltzmann Surface Area (MM-PBSA) calculations as well as favorable ADME/Tox properties. The molecules were also predicted as antiviral, anti-inflammatory, membrane permeability inhibitors, RNA synthesis inhibitors, cytoprotective, and hepatoprotective with probable activity (Pa) above 0.5 and probable inactivity values below 0.1. Some of them also have anti-influenza activity. Influenza virus has many similarities with SARS-CoV-2 in their mode of entry into human cells as both are facilitated by the furin protease. Pinobanksin 3-(E)-caffeate, one of the potential leads is a propolis compound. Propolis compounds have shown inhibitory effects against ACE2, TMPRSS2, and PAK1 signaling pathways of SARS-CoV-2 in previous studies. Likewise, quercitrin is structurally similar to isoquercetin, which is currently in clinical trials as possible medication for COVID-19.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11224-022-02056-1.

Loss of the Schizophrenia-Linked Furin Protein from Drosophila Mushroom Body Neurons Results in Antipsychotic-Reversible Habituation Deficits.

Habituation is a conserved adaptive process essential for incoming information assessment, which drives the behavioral response decrement to recurrent inconsequential stimuli and does not involve sensory adaptation or fatigue. Although the molecular mechanisms underlying the process are not well understood, habituation has been reported to be defective in a number of disorders including schizophrenia. We demonstrate that loss of furin1, the Drosophila homolog of a gene whose transcriptional downregulation has been linked to schizophrenia, results in defective habituation to recurrent footshocks in mixed sex populations. The deficit is reversible by transgenic expression of the Drosophila or human Furin in adult α'/β' mushroom body neurons and by acute oral delivery of the typical antipsychotic haloperidol and the atypical clozapine, which are commonly used to treat schizophrenic patients. The results validate the proposed contribution of Furin downregulation in schizophrenia and suggest that defective footshock habituation is a Drosophila protophenotype of the human disorder.SIGNIFICANCE STATEMENT Genome-wide association studies have revealed a number of loci linked to schizophrenia, but most have not been verified experimentally in a relevant behavioral task. Habituation deficits constitute a schizophrenia endophenotype. Drosophila with attenuated expression of the schizophrenia-linked highly conserved Furin gene present delayed habituation reversible with acute exposure to antipsychotics. This strongly suggests that footshock habituation defects constitute a schizophrenia protophenotype in Drosophila Furthermore, determination of the neurons whose regulated activity is required for footshock habituation provides a facile metazoan system to expediently validate putative schizophrenia genes and variants in a well understood simple brain.

Cationic Geminoid Peptide Amphiphiles Inhibit DENV2 Protease, Furin, and Viral Replication.

Dengue is an important arboviral infectious disease for which there is currently no specific cure. We report gemini-like (geminoid) alkylated amphiphilic peptides containing lysines in combination with glycines or alanines (C15H31C(O)-Lys-(Gly or Ala)nLys-NHC16H33, shorthand notation C16-KXnK-C16 with X = A or G, and n = 0–2). The representatives with 1 or 2 Ala inhibit dengue protease and human furin, two serine proteases involved in dengue virus infection that have peptides with cationic amino acids as their preferred substrates, with IC50 values in the lower µM range. The geminoid C16-KAK-C16 combined inhibition of DENV2 protease (IC50 2.3 µM) with efficacy against replication of wildtype DENV2 in LLC-MK2 cells (EC50 4.1 µM) and an absence of toxicity. We conclude that the lysine-based geminoids have activity against dengue virus infection, which is based on their inhibition of the proteases involved in viral replication and are therefore promising leads to further developing antiviral therapeutics, not limited to dengue.

Chemi-Informatic Approach to Investigate Putative Pharmacoactive Agents of Plant Origin to Eradicate COVID-19

Background:: The scientific community has supported from the medicinal flora of ancient as well as modern times in extracting chemicals, which holds therapeutic potential. In many previous studies, it was discovered Amentoflavone as an anti-viral agent and its presence as a bioactive constituent in many plants of different families Selaginellaceae, Euphorbiaceae, and Calophyllaceae etc. Withania somnifera (Ashwagandha) is already considered significant anti-viral agent in traditional medicine, and it is the main source of Somniferine-A, Withanolide-B. Objective:: In this study phytochemicals such as Withanolide-B, Somniferine-A, Stigmasterol, Amentoflavone, and Chavicine were analyzed to screen protein inhibitors out of them; such proteins are involved in SARS-Cov-2's internalization and interaction with human cytological domains. This will help in developing check point for SARS-Cov-2 internalization. Material and methods:: Chemi-informatic tools like basic local alignment search tool (BLAST), AutoDock-vina, SwissADME, MDWeb, Molsoft, ProTox-II, and LigPlot were deployed to examine the action of pharmacoactive agents against SARS-Cov-2. The many tools deployed in the study were based on finest algorithms like Artificial neural networking, Machine Learning, and Artificial intelligence. Results:: On the basis of binding energies less than equal to -8.5 kcal/mol. Amentoflavone, Stigmasterol, and Somniferine-A were found to be most effective against COVID-19 disease as these chemical agents exhibit hydrogen bond interactions and competitively inhibit major proteins (SARS-Cov-2 Spike, Human ACE-2 receptor, Human Furin protease, SARS-Cov-2 RNA binding protein) that are found to involved in its infection and pathogenesis. Simulation analysis provides more validity to the selection of drug candidate Amentoflavone. ADMET properties were found to be in feasible range for putative drug candidates. Conclusion:: Computational analysis was successfully deployed in searching pharmacoactive phytochemicals Like Amentoflavone, Somniferine-A, and Stigmasterol that can bring control over COVID-19 expansion. This new methodology was found to be efficient, as reduces monetary expenditures and time consumption, aftermath molecular wet-lab validations will provide better approval for finalizing our selected drug model for controlling COVID-19 pandemic.

Discovery of diminazene as a dual inhibitor of SARS-CoV-2 human host proteases TMPRSS2 and furin using cell-based assays.

The proteases TMPRSS2 (transmembrane protease serine 2) and furin are known to play important roles in viral infectivity including systematic COVID-19 infection through priming of the spike protein of SARS-CoV-2 and related viruses. To discover small-molecules capable of inhibiting these host proteases, we established convenient and cost-effective cell-based assays employing Vero cells overexpressing TMPRSS2 and furin. A cell-based proteolytic assay for broad-spectrum protease inhibitors was also established using human prostate cancer cell line LNCaP. Evaluation of camostat, nafamostat, and gabexate in these cell-based assays confirmed their known TMPRSS2 inhibitory activities. Diminazene, a veterinary medicinal agent and a known furin inhibitor was found to inhibit both TMPRSS2 and furin with IC50s of 1.35 and 13.2 μM, respectively. Establishment and the use of cell-based assays for evaluation TMPRSS2 and furin inhibitory activity and implications of dual activity of diminazene vs TMPRSS2 and furin are presented.

Iterated Virtual Screening-Assisted Antiviral and Enzyme Inhibition Assays Reveal the Discovery of Novel Promising Anti-SARS-CoV-2 with Dual Activity

Unfortunately, COVID-19 is still a threat to humankind and has a dramatic impact on human health, social life, the world economy, and food security. With the limited number of suggested therapies under clinical trials, the discovery of novel therapeutic agents is essential. Here, a previously identified anti-SARS-CoV-2 compound named Compound 13 (1,2,5-Oxadiazole-3-carboximidic acid, 4,4′-(methylenediimino) bis,bis[[(2-hydroxyphenyl)methylene]hydrazide) was subjected to an iterated virtual screening against SARS-CoV-2 Mpro using a combination of Ligand Designer and PathFinder. PathFinder, a computational reaction enumeration tool, was used for the rapid generation of enumerated structures via default reaction library. Ligand designer was employed for the computerized lead optimization and selection of the best structural modification that resulted in a favorable ligand–protein complex. The obtained compounds that showed the best binding to Mpro were re-screened against TMPRSS2, leading to the identification of 20 shared compounds. The compounds were further visually inspected, which resulted in the identification of five shared compounds M1–5 with dual binding affinity. In vitro evaluation and enzyme inhibition assay indicated that M3, an analogue of Compound 13 afforded by replacing the phenolic moiety with pyridinyl, possesses an improved antiviral activity and safety. M3 displayed in vitro antiviral activity with IC50 0.016 µM and Mpro inhibition activity with IC50 0.013 µM, 7-fold more potent than the parent Compound 13 and potent than the antivirals drugs that are currently under clinical trials. Moreover, M3 showed potent activity against human TMPRSS2 and furin enzymes with IC50 0.05, and 0.08 µM, respectively. Molecular docking, WaterMap analysis, molecular dynamics simulation, and R-group analysis confirmed the superiority of the binding fit to M3 with the target enzymes. WaterMap analysis calculated the thermodynamic properties of the hydration site in the binding pocket that significantly affects the biological activity. Loading M3 on zinc oxide nanoparticles (ZnO NPs) increased the antiviral activity of the compound 1.5-fold, while maintaining a higher safety profile. In conclusion, lead optimized discovery following an iterated virtual screening in association with molecular docking and biological evaluation revealed a novel compound named M3 with promising dual activity against SARS-CoV-2. The compound deserves further investigation for potential clinical-based studies.

Site-Specific Glycosylation of Recombinant Viral Glycoproteins Produced in Nicotiana benthamiana.

There is an urgent need to establish large scale biopharmaceutical manufacturing capacity in Africa where the infrastructure for biologics production is severely limited. Molecular farming, whereby pharmaceuticals are produced in plants, offers a cheaper alternative to mainstream expression platforms, and is amenable to rapid large-scale production. However, there are several differences along the plant protein secretory pathway compared to mammalian systems, which constrain the production of complex pharmaceuticals. Viral envelope glycoproteins are important targets for immunization, yet in some cases they accumulate poorly in plants and may not be properly processed. Whilst the co-expression of human chaperones and furin proteases has shown promise, it is presently unclear how plant-specific differences in glycosylation impact the production of these proteins. In many cases it may be necessary to reproduce features of their native glycosylation to produce immunologically relevant vaccines, given that glycosylation is central to the folding and immunogenicity of these antigens. Building on previous work, we transiently expressed model glycoproteins from HIV and Marburg virus in Nicotiana benthamiana and mammalian cells. The proteins were purified and their site-specific glycosylation was determined by mass-spectrometry. Both glycoproteins yielded increased amounts of protein aggregates when produced in plants compared to the equivalent mammalian cell-derived proteins. The glycosylation profiles of the plant-produced glycoproteins were distinct from the mammalian cell produced proteins: they displayed lower levels of glycan occupancy, reduced complex glycans and large amounts of paucimannosidic structures. The elucidation of the site-specific glycosylation of viral glycoproteins produced in N. benthamiana is an important step toward producing heterologous viral glycoproteins in plants with authentic human-like glycosylation.

A Comparative Study of Approved Drugs for SARS-CoV-2 by Molecular Docking

SARS-CoV-2, a new type of Coronavirus, has affected more millions of people worldwide. From the spread of this infection, many studies related to this virus and drug designing for the treatment have been started. Most of the studies target the SARS-CoV-2 main protease, spike protein of SASR-CoV-2, and some are targeting the human furin protease. In the current work, we chose the clinically used drug molecules remdesivir, favipiravir, lopinavir, hydroxychloroquine, and chloroquine onto the target protein SARS-CoV-2 main protease. Docking studies were performed using Arguslab, while Discovery Studio collected 2D and 3D pose views with the crystal structure of COVID-19 main protease in complex with an inhibitor N3 with PDB ID 6LU7. Computational studies reveal that all ligands provided good binding affinities towards the target protein. Among all the chosen drugs, lopinavir showed the highest docking score of -11.75 kcal/mol. The results from this molecular docking study encourage the use of lopinavir as the first-line treatment drug due to its highest binding affinity.

Promising anti-SARS-CoV-2 drugs by effective dual targeting against the viral and host proteases

SARS-CoV-2 caused dramatic health, social and economic threats to the globe. With this threat, the expectation of future outbreak, and the shortage of anti-viral drugs, scientists were challenged to develop novel antivirals. The objective of this study is to develop novel anti-SARS-CoV-2 compounds with dual activity by targeting valuable less-mutated enzymes. Here, we have mapped the binding affinity of >500,000 compounds for potential activity against SARS-CoV-2 main protease (Mpro), papain protease (PLpro) and human furin protease. The enzyme inhibition activity of most promising hits was screened and tested in vitro on SARS-CoV-2 clinical isolate incubated with Vero cells. Computational modelling and toxicity of the compounds were validated. The results revealed that 16 compounds showed potential binding activity against Mpro, two of them showed binding affinity against PLpro and furin protease. Respectively, compounds 7 and 13 showed inhibition activity against Mpro at IC50 0.45 and 0.11 µM, against PLpro at IC50 0.085 and 0.063 µM, and against furin protease at IC50 0.29 µM. Computational modelling validated the binding affinity against all proteases. Compounds 7 and 13 showed significant inhibition activity against the virus at IC50 0.77 and 0.11 µM, respectively. Both compounds showed no toxicity on mammalian cells. The data obtained indicated that compounds 7 and 13 exhibited potent dual inhibition activity against SARS-CoV-2. The dual activity of both compounds can be of great promise not only during the current pandemic but also for future outbreaks since the compounds’ targets are of limited mutation and critical importance to the viral infection.

Potential combination therapy using twenty phytochemicals from twenty plants to prevent SARS- CoV-2 infection: An in silico Approach.

Covid 19 caused by novel strain SARS- CoV-2 has become a pandemic due to its contagious nature of infection. It enters by binding with ACE2 receptor present on the outer surface of a cell by cleaving S1/S2 with proteolytic protein Furin. Further viral replication or transcription then takes place with the help of main protease 3CLpro and polymerase RdRp. This in silco study was carried out to block ACE2, Furin, 3CLpro and RdRP with various phytochemicals to prevent SARS- CoV-2 entry and replication or transcription. Twenty different phytochemicals were screened to understand the drug-likeliness obeying Lipinski’s rule 5 and further, molecular docking was performed using these phytochemicals to block their respective target proteins. All the phytochemicals follow Lipinski’s rule of five and molecular docking result shows best binding affinity of Podofilox − 7.54 kcal/mol with ACE2, Psoralidin − 8.04 kcal/mol with Furin, Ursolic acid − 8.88 kcal/mol with 3CLpro and Epiafzelechin − 8.26 kcal/mol with RdRp. Thus, blocking two human receptors ACE2 and Furin with Podofilox and Psoralidin respectively may prevent the viral entry into the cells. Also blocking viral proteins 3CLpro and RdRp with Ursolic acid and Epiafzelechin may prevent viral replication or transcription. Using this combination therapy of blocking the receptors responsible for viral entry and viral proteins responsible for replication or transcription may prevent SARS- CoV-2 infection.

Comparison of clinically approved molecules on SARS-CoV-2 drug target proteins: a molecular docking study.

The new type of coronavirus, SARS-CoV-2 has affected more than 22.6 million people worldwide. Since the first day the virus was spotted in Wuhan, China, numerous drug design studies have been conducted all over the globe. Most of these studies target the receptor-binding domain of spike protein of SARS-CoV-2, which is known to bind to the human ACE2 receptor and SARS-CoV-2 main protease, vital for the virus’ replication. However, there might be a third target, human furin protease, which cleaves the virus’ S1-S2 domains playing an active role in its entry into the host cell. In this study, we docked five clinically used drug molecules, favipiravir, hydroxychloroquine, remdesivir, lopinavir, and ritonavir onto three target proteins, the receptor-binding domain of SARS-CoV-2 spike protein, SARS-CoV-2 main protease, and human furin protease. Results of molecular docking simulations revealed that human furin protease might be targeted by COVID-19. Remdesivir, a nucleic acid derivative, strongly bound to the active site of this protease, suggesting that this molecule can be used as a template for designing novel furin protease inhibitors to fight against the disease. Protein-drug interactions revealed in this study at the molecular level, can pave the way for better drug design for each specific target.

Identification of potential inhibitors of SARS-CoV-2 from Artemisia annua compounds by In silico evaluation and their density functional theory (DFT)

The genus Artemisia has recognized medicinal value and its use by humans Dates back to centuries ago. With the appearance of the new coronavirus, end of 2019, several countries have recommended the use of herbal teas consisting mainly of Artemisia. The individual analysis of the constituents of this species is crucial to characterize and optimize its antiSARS-Cov-2 action. We evaluated by molecular docking the inhibitory action of major compounds of the Artemisia genus (Artemisinin, Arteannuin B, Alpha Thujone, P-Hydroxyacetophenone, Fisetin, Cirsimaritin, Capillin, β-Sitosterol, and Quercetin) against three targets namely SARS-CoV-2 main protease (Mp), SARS-CoV-2 receptor binding domain (RBD) and human furin protease (HF protease). The two flavonols, quercetin and fisetin, have the best binding energies with the three targets. Quercetin/Fisetin possesses binding energy of -7.17/-6.9, -6.3/-6.15 and – 5.98/- 5.49 kcal/mol with MP, RBD and HF protease respectively. Their physicochemical properties meet the requirements of an oral active principle and are not toxic according to predictive simulations. Thereby DFT calculation has been used to analyze the electronic and geometric characteristics of these two compounds. The gap energies were also deduced for the stable structure and their reactivity. The abundance of Quercetin in different plants may be another advantage in the use of this bio-compound in the treatment of coronavirus. Keywords: Artemisia annua, DFT, Docking Molecular, SARS-Cov-2, Quercetin and Fisetin

Assessing the consequences of environmental exposures on the expression of the human receptor and proteases involved in SARS-CoV-2 cell-entry

The role of environmental condition on the infection by the novel pathogenic SARS-CoV-2 virus remains uncertain. In here, exploiting a large panel of publicly available genome-wide data, we investigated whether the human receptor ACE2 and human proteases TMPRSS2, FURIN and CATHEPSINs (B, L and V), which are involved in SARS-CoV-2 cell entry, are transcriptionally regulated by environmental cues. We report that more than 50 chemicals modulate the expression of ACE2 or human proteases important for SARS-CoV-2 cell entry. We further demonstrate that transcription factor AhR, which is commonly activated by pollutants, binds to the promoter of TMPRSS2 and enhancers and/or promoters of Cathepsin B, L and V encoding genes. Our exploratory study documents an influence of environmental exposures on the expression of genes involved in SARS-CoV-2 cell entry. These results could be conceptually and medically relevant to our understanding of the COVID-19 disease, and should be further explored in laboratory and epidemiologic studies.

Design, Engineering and Discovery of Novel α-Helical and β-Boomerang Antimicrobial Peptides against Drug Resistant Bacteria.

In an era where the pipeline of new antibiotic development is drying up, the continuous rise of multi-drug resistant (MDR) and extensively drug resistant (XDR) bacteria are genuine threats to human health. Although antimicrobial peptides (AMPs) may serve as promising leads against drug resistant bacteria, only a few AMPs are in advanced clinical trials. The limitations of AMPs, namely their low in vivo activity, toxicity, and poor bioavailability, need to be addressed. Here, we review engineering of frog derived short α-helical AMPs (aurein, temporins) and lipopolysaccharide (LPS) binding designed β-boomerang AMPs for further development. The discovery of novel cell selective AMPs from the human proprotein convertase furin is also discussed.