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70 result(s) for "Shekhar, Nishant"
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Drug targets for corona virus: A systematic review
The 2019-novel coronavirus (nCoV) is a major source of disaster in the 21th century. However, the lack of specific drugs to prevent/treat an attack is a major need at this current point of time. In this regard, we conducted a systematic review to identify major druggable targets in coronavirus (CoV). We searched PubMed and RCSB database with keywords HCoV, NCoV, corona virus, SERS-CoV, MERS-CoV, 2019-nCoV, crystal structure, X-ray crystallography structure, NMR structure, target, and drug target till Feb 3, 2020. The search identified seven major targets (spike protein, envelop protein, membrane protein, protease, nucleocapsid protein, hemagglutinin esterase, and helicase) for which drug design can be considered. There are other 16 nonstructural proteins (NSPs), which can also be considered from the drug design perspective. The major structural proteins and NSPs may serve an important role from drug design perspectives. However, the occurrence of frequent recombination events is a major deterrent factor toward the development of CoV-specific vaccines/drugs.
In-silico discovery of dual active molecule to restore synaptic wiring against autism spectrum disorder via HDAC2 and H3R inhibition
Metal-dependent histone deacetylases (HDACs) are essential epigenetic regulators; their molecular and pharmacological roles in medically critical diseases such as neuropsychiatric disorders, neurodegeneration, and cancer are being studied globally. HDAC2’s differential expression in the central nervous system makes it an appealing therapeutic target for chronic neurological diseases like autism spectrum disorder. In this study, we identified H3R inhibitor molecules that are computationally effective at binding to the HDAC2 metal-coordinated binding site. The study highlights the importance of pitolisant in screening the potential H3R inhibitors by using a hybrid workflow of ligand and receptor-based drug discovery. The screened lead compounds with PubChem SIDs 103179850, 103185945, and 103362074 show viable binding with HDAC2 in silico . The importance of ligand contacts with the Zn 2+ ion in the HDAC2 catalytic site is also discussed and investigated for a significant role in enzyme inhibition. The proposed H3R inhibitors 103179850, 103185945, and 103362074 are estimated as dual-active molecules to block the HDAC2-mediated deacetylation of the EAAT2 gene (SLC1A2) and H3R-mediated synaptic transmission irregularity and are, therefore, open for experimental validation.
Antiparasitic effect of Farnesol against Leishmania major: A rationale from in vitro and in silico investigations
Leishmaniasis is a vector-borne parasitic infection caused by the infective bite of female Phlebotomine sandflies. Treatment of leishmaniasis by conventional synthetic compounds is met by challenges pertaining to adverse effects which call for the discovery of newer anti-leishmanial molecules. This study was performed to evaluate the effect and modes of action of a sesquiterpene alcoholic molecule Farnesol on Leishmania major, the causative agent of Zoonotic CL. The cytotoxic effect of Farnesol against L . major promastigotes, amastigotes and macrophages was assessed by MTT test and counting. The IC 50 on promastigotes by Farnesol on L . major was also evaluated by flow cytometry. In the findings, promastigotes were reduced at 167μM. The mean numbers of L . major amastigotes in macrophages were significantly decreased on exposure to Farnesol at 172μM. In addition, Farnesol induced significant apoptosis dose-dependent on L . major promastigotes. In silico protein-ligand_binding analyses indicated the effect of Farnesol in perturbation of the ergosterol synthesis pathway of Leishmania with attributes suggesting inhibition of Lanosterol-α-demethylase, the terminal enzyme of ergosterol synthesis machinery. Findings from flow cytometry reveal the role of Farnesol in apoptosis-induced killing in promastigotes. Farnesol was effective at very lower concentrations when compared to Paromomycin. Further studies are crucial to evaluate the therapeutic potential of Farnesol alone or in combination with other conventional drugs in animal models.
Emergence of Bordetella holmesii –Associated Pertussis-Like Illness, Northern India, 2019–2023
We investigated Bordetella holmesii and Bordetella pertussis in 935 suspected pertussis cases in northern India (2019-2023) using PCR and serology. B. holmesii showed increased prevalence in pertussis cases, particularly in older children, highlighting its emerging role and the need for ongoing surveillance and adjusted prevention strategies.
Investigating the novel-binding site of RPA2 on Menin and predicting the effect of point mutation of Menin through protein–protein interactions
Protein–protein interactions (PPIs) play a critical role in all biological processes. Menin is tumor suppressor protein, mutated in multiple endocrine neoplasia type 1 syndrome and has been shown to interact with multiple transcription factors including (RPA2) subunit of replication protein A (RPA). RPA2, heterotrimeric protein required for DNA repair, recombination and replication. However, it’s still remains unclear the specific amino acid residues that have been involved in Menin-RPA2 interaction. Thus, accurately predicting the specific amino acid involved in interaction and effects of MEN1 mutations on biological systems is of great interests. The experimental approaches for identifying amino acids in menin-RPA2 interactions are expensive, time-consuming, and challenging. This study leverages computational tools, free energy decomposition and configurational entropy scheme to annotate the menin-RPA2 interaction and effect on menin point mutation, thereby proposing a viable model of menin-RPA2 interaction. The menin–RPA2 interaction pattern was calculated on the basis of different 3D structures of menin and RPA2 complexes, constructed using homology modeling and docking strategy, generating three best-fit models: Model 8 (− 74.89 kJ/mol), Model 28 (− 92.04 kJ/mol) and Model 9 (− 100.4 kJ/mol). The molecular dynamic (MD) was performed for 200 ns and binding free energies and energy decomposition analysis were calculated using Molecular Mechanics Poisson–Boltzmann Surface Area (MM/PBSA) in GROMACS. From binding free energy change, model 8 of Menin-RPA2 exhibited most negative binding energy of − 205.624 kJ/mol, followed by model 28 of Menin-RPA2 with − 177.382 kJ/mol. After S606F point mutation in Menin, increase of BFE (ΔG bind ) by − 34.09 kJ/mol in Model 8 of mutant Menin-RPA2 occurs. Interestingly, we found a significant reduction of BFE (ΔG bind ) and configurational entropy by − 97.54 kJ/mol and − 2618 kJ/mol in mutant model 28 as compared the o wild type. Collectively, this is the first study to highlight the configurational entropy of protein–protein interactions thereby strengthening the prediction of two significant important interaction sites in menin for the binding of RPA2. These predicted sites could be vulnerable for structural alternation in terms of binding free energy and configurational entropy after missense mutation in menin.
Efficacy and safety of steroid therapy in COVID-19: A rapid systematic review and Meta-analysis
PURPOSE: Although the use of steroids in the management of COVID-19 has been addressed by a few systematic review and meta-analysis, however, they also used data from \"SARS-CoV\" and \"MERS-CoV.\" Again, most of these studies addressed only one severity category of patients or addressed only one efficacy endpoint (mortality). In this context, we conducted this meta-analysis to evaluate the efficacy and safety of steroid therapy among all severity categories of patients with COVID-19 (mild to moderate and severe to critical category) in terms of \"mortality,\" \"requirement of mechanical ventilation,\" \"requirement of ICU\" and clinical cure parameters. METHODS: 11 databases were screened. Only randomized controlled trials (RCTs) or high quality (on the basis of risk of bias analysis) comparative-observational studies were included in the analysis. RevMan5.3 was used for the meta-analysis. RESULTS: A total of 15 studies (3 RCT and 12 comparative-observational studies) were included. In the mechanically-ventilated COVID-19 population, treatment with dexamethasone showed significant protection against mortality (single study). Among severe and critically ill combined population, steroid administration was significantly associated with lowered mortality (risk ratio [RR] 0.83 [0.76-0.910]), lowered requirement of mechanical ventilation (RR 0.59 [0.51-0.69]), decreased requirement of intensive care unit (ICU) (RR 0.62 [0.45-0.86]), lowered length of ICU stay (single-study) and decreased duration of mechanical ventilation (two-studies). In mild to moderate population, steroid treatment was associated with a higher \"duration of hospital stay,\" while no difference was seen in other domains. In patients at risk of progression to \"acute respiratory distress syndrome,\" steroid administration was associated with \"reduced requirement of mechanical ventilation\" (single-study). CONCLUSION: This study guides the use of steroid across patients with different severity categories of COVID-19. Among mechanically ventilated patients, steroid therapy may be beneficial in terms of reduced mortality. Among \"severe and critical\" patients; steroid therapy was associated with lowered mortality, decreased requirement of mechanical ventilation, and ICU. However, no benefit was observed in \"mild to moderate\" population. To conclude, among properly selected patient populations (based-upon clinical severity and biomarker status), steroid administration may prove beneficial in patients with COVID-19.
In Silico Structure-Based Repositioning of Approved Drugs for Spike Glycoprotein S2 Domain Fusion Peptide of SARS-CoV-2: Rationale from Molecular Dynamics and Binding Free Energy Calculations
The present study provides the structural identification of the viable binding residues of the SARS-CoV-2 S2 fusion peptide region, which holds prime importance in the virus’s host cell fusion and entry mechanism. The classical molecular mechanics simulations were set on values that mimic physiological standards for a good approximation of the dynamic behavior of selected drugs in biological systems. The drug molecules screened and analyzed here have relevant antiviral properties, which are reported here and which might hint toward their utilization in the coronavirus disease 2019 (COVID-19) pandemic owing to their attributes of binding to the fusion protein binding region shown in this study. The membrane-anchored spike (S) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has a pivotal role in directing the fusion of the virus particle mediated by the host cell receptor angiotensin-converting enzyme 2 (ACE-2). The fusion peptide region of the S protein S2 domain provides SARS-CoV-2 with the biological machinery needed for direct fusion to the host lipid membrane. In our present study, computer-aided drug design strategies were used for the identification of FDA-approved small molecules using the optimal structure of the S2 domain, which exhibits optimal interaction ratios, structural features, and energy variables, which were evaluated based on their performances in molecular docking, molecular dynamics simulations, molecular mechanics/generalized Born model and solvent accessibility binding free energy calculations of molecular dynamics trajectories, and statistical inferences. Among the 2,625 FDA-approved small molecules, chloramphenicol succinate, imipenem, and imidurea turned out to be the molecules that bound the best at the fusion peptide hydrophobic pocket. The principal interactions of the selected molecules suggest that the potential binding site at the fusion peptide region is centralized amid the Lys790, Thr791, Lys795, Asp808, and Gln872 residues. IMPORTANCE The present study provides the structural identification of the viable binding residues of the SARS-CoV-2 S2 fusion peptide region, which holds prime importance in the virus’s host cell fusion and entry mechanism. The classical molecular mechanics simulations were set on values that mimic physiological standards for a good approximation of the dynamic behavior of selected drugs in biological systems. The drug molecules screened and analyzed here have relevant antiviral properties, which are reported here and which might hint toward their utilization in the coronavirus disease 2019 (COVID-19) pandemic owing to their attributes of binding to the fusion protein binding region shown in this study.
Structural-Based Virtual Screening of FDA-Approved Drugs Repository for NSP16 Inhibitors, Essential for SARS-COV-2 Invasion Into Host Cells: Elucidation From MM/PBSA Calculation
NSP16 is one of the structural proteins of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) necessary for its entrance to the host cells. It exhibits 2’O-methyl-transferase (2’O-MTase) activity of NSP16 using methyl group from S-adenosyl methionine (SAM) by methylating the 5-end of virally encoded mRNAs and shields viral RNA, and also controls its replication as well as infection. In the present study, we used in silico approaches of drug repurposing to target and inhibit the SAM binding site in NSP16 using Food and Drug Administration (FDA)-approved small molecules set from Drug Bank database. Among the 2 456 FDA-approved molecules, framycetin, paromomycin, and amikacin were found to be significant binders against the SAM binding cryptic pocket of NSP16 with docking score of –13.708, –14.997 and –15.841 kcal/mol, respectively. Classical molecular dynamics (MD) simulation and molecular mechanics Poisson−Boltzmann surface area (MM/PBSA)-based binding free energy calculation depicted that all these three framycetin, paromomycin, and amikacin might be promising therapeutic leads towards SARS-CoV-2 infections via host immune escape inhibition pathway.
In silico docking and comparative ADMET profile of different glycogen synthase kinase 3 beta inhibitors as the potential leads for the development of anti-Alzheimer drug therapy
Glycogen synthase kinase 3 beta (GSK3 β) plays a key role in pathologic hyper phosphorylation of tau and plays an important role in the pathogenesis of Alzheimer's disease. In the present study, we have screened a set of potential hits in in silico platform to gain insight regarding binding profile with the target (GSK3 β) from molecular docking, ADME/T, and molecular dynamics (MD) simulations. The three screened compounds 6-BIBEO, 6-BIO, and SB216763 topped the docking score chart when subjected to hard scoring function extraprecision of GLIDE. The active site dynamics study through MD simulations provides insights on residues Asp133, Val135, and Ile62 which are in a state of minimum deviation from their mean special position while they interact with the respective ligands. The same molecules also displayed favorable pharmacokinetic profile, negative Ames test and falls correctly within drug-likeliness rules. These agents can be taken forward further for the development of anti-Alzheimer's drug therapy.
Update on the target structures of SARS-CoV-2: A systematic review
Knowledge of structural details is very much essential from the drug-design perspective. In the systematic review, we systematically reviewed the structural basis of different target proteins of SARS-corona virus (CoV2) from a viral life cycle and from drug design perspective. We searched four literature (PubMed, EMBASE, NATURE, and Willey online library) databases and one structural database (RCSB.org) with appropriate keywords till April 18, and finally, 26 articles were included in the systematic review. The published literature mainly centered upon the structural details of \"spike protein,\" \"main protease/M Pro/3CL pro,\" \"RNA-dependent RNA polymerase,\" and \"nonstructural protein 15 Endoribonuclease\" of SARS-CoV-2. However, inhibitor bound structures were very less. We need better structures elucidating the interactions between different targets and their inhibitors which will help us in understanding the atomic level importance of different amino acid residues in the functionality of the target structures. To summarize, we need structures with fine resolution, co-crystallized structures with biologically validated inhibitors, and functional characterization of different target proteins. Some other routes of entry of SARS-CoV-2 are also mentioned (e.g., CD147); however, these findings are not structurally validated. This review may pave way for better understanding of SARS-CoV-2 life cycle from structural biology perspective.