Pan-India influenza-like illness (ILI) and Severe acute respiratory infection (SARI) surveillance: epidemiological, clinical and genomic analysis.

Background: Over time, COVID-19 testing has significantly declined across the world. However, it is critical to monitor the virus through surveillance. In late 2020, WHO released interim guidance advising the use of the existing Global Influenza Surveillance and Response System (GISRS) for the integrated surveillance of influenza and SARS-CoV-2. Methods: In July 2021, we initiated a pan-India integrated surveillance for influenza and SARS-CoV-2 through the geographically representative network of Virus Research and Diagnostic Laboratories (VRDLs) across 26 hospital and laboratory sites and 70 community sites. A total of 34,260 cases of influenza-like illness (ILI) and Severe acute respiratory infection (SARI) were enrolled from 4 July 2021 to 31 October 2022. Findings: Influenza A(H3) and B/Victoria dominated during 2021 monsoon season while A(H1N1)pdm09 dominated during 2022 monsoon season. The SARS-CoV-2 "variants of concern" (VoC) Delta and Omicron predominated in 2021 and 2022, respectively. Increased proportion of SARI was seen in extremes of age: 90% cases in < 1 year; 68% in 1 to 5 years and 61% in ≥ 8 years age group. Approximately 40.7% of enrolled cases only partially fulfilled WHO ILI and SARI case definitions. Influenza- and SARS-CoV-2-infected comorbid patients had higher risks of hospitalization, ICU admission, and oxygen requirement. Interpretation: The results depicted the varying strains and transmission dynamics of influenza and SARS-CoV-2 viruses over time, thus emphasizing the need to continue and expand surveillance across countries for improved decision making. The study also describes important information related to clinical outcomes of ILI and SARI patients and highlights the need to review existing WHO ILI and SARI case definitions.

Molecular docking analysis of Omt-A protein model from Aspergillus flavus with synthetic compounds.

Aflatoxin is a potent mycotoxin of Aspergillus flavus that has been classified as a Group I carcinogen. O-methyltransferase A (Omt-A) is a critical enzyme in the formation of aflatoxin. It catalyzes the methylation of norsalic acid to form the highly toxic intermediate averantin. The ligand-protein interaction of Omt-A was performed with piperlonguminin and blasticidins. The maximum affinity of -10.6 was found for the 5ICC_A piperlonguminine at site1 (X,Y,Z: -15.282, 21.785, 5.672). Compounds such as Blasticidin S, Neoeriocitrin, Blasticidin S - hydrochloric acid, 6,6''-Bigenkwanin, Pipernomaline, and Eriodictyol were found to have binding features to protein residues, as shown by computational interaction at the molecular level.

A Review of miRNA Regulation in Japanese Encephalitis (JEV) Virus Infection.

Japanese encephalitis (JE) is a mosquito-borne disease that causes neuronal damage and inflammation of microglia, and in severe cases, it can be fatal. JE infection can resist cellular immune responses and survive in host cells. Japanese encephalitis virus (JEV) infects macrophages and peripheral blood lymphocytes. In addition to regulating biological signaling pathways, microRNAs in cells also influence virus-host interactions. Under certain circumstances, viruses can change microRNA production. These changes affect the replication and spread of the virus. Host miRNAs can contain viral pathogenicity by downregulating the antiviral immune response pathways. Simultaneous profiling of miRNA and messenger RNA (mRNA) could help us detect pathogenic factors, and dual RNA detection is possible. This work highlights important miRNAs involved in human JE infection. In this study, we have shown the important miRNAs that play significant roles in JEV infection. We found that during JEV infection, miRNA-155, miR-29b, miRNA-15b, miR-146a, miRNA-125b-5p, miRNA-30la, miR-19b-3p, and miR-124, cause upregulation of human genes whereas miRNA-432, miRNA-370, microRNA-33a-5p, and miRNA-466d-3p are responsible for downregulation of human genes respectively. Further, these miRNAs are also responsible for the inflammatory effects. Although several other miRNAs critical to the JEV life cycle are yet unknown, there is currently no evidence for the role of miRNAs in persistence.

Interaction between Cfd1 and Nbp35 proteins involved in cytosolic FeS cluster assembly machinery deciphers a stable complexation in Leishmania donovani.

Leishmania donovani is the causative unicellular parasite for visceral leishmaniasis (VL); and FeS proteins are likely to be very essential for their survival and viability. Cytosolic FeS cluster assembly (CIA) machinery is one of the four systems for the biosynthesis and transfer of FeS clusters among eukaryotes; Cfd1 and Nbp35 are the scaffold components for cytosolic FeS cluster biogenesis. We investigated the role of CIA machinery components and purified Cfd1 and Nbp35 proteins of L. donovani. We also investigated the interactive nature between LdCfd1 and LdNbp35 proteins by in silico analysis, in vitro co-purification, pull down assays along with in vivo immuno-precipitation; which inferred that both LdCfd1 and LdNbp35 proteins are interacting with each other. Thus, our collective data revealed the interaction between these two proteins which forms a stable complex that can be attributed to the cellular process of FeS clusters biogenesis, and transfer to target apo-proteins of L. donovani. The expression of Cfd1 and Nbp35 proteins in Amp B resistant parasites is up-regulated leading to increased amount of FeS proteins. Hence, it favors increased tolerance towards ROS level, which helps parasites survival under drug pressure contributing in Amphotericin B resistance.

Hepatitis C virus seroprevalence among patients enrolled at the opioid substitution therapy center in Bihar: A cross-sectional study.

BACKGROUND AND AIM: Hepatitis C virus (HCV) infection poses a major public health challenge in Indian settings due to its huge population and easy transmissibility of HCV among individuals who inject drugs (PWID, which is increasing in India). The National AIDS Control Organization (NACO), India has started the Opioid Substitution Therapy (OST) centers to improve the health status of opioid dependent PWID and prevent the spread of HIV/AIDS among them. We conducted a cross-sectional study to find out the HCV sero-positive status and associated determinants in patients attending the OST centre in the ICMR-RMRIMS, Patna. MATERIALS AND METHODS: We utilized the routinely collected (as a part of the National AIDS Control Program) and de-identified data from the OST center from 2014 to 2022 (N = 268). We abstracted the information for exposure variables (such as socio-demographic features and drug history) and outcome variable (HCV serostatus). The association of exposure variables with HCV serostatus was examined using robust Poisson regression. RESULTS: All the enrolled participants were male and the prevalence of HCV seropositivity was 28% [95% confidence interval (CI): 22.7% - 33.8%)]. There was a rising prevalence of HCV seropositivity with number of years of injection use (p-trend <0.001) and age (p-trend 0.025). Approximately, 6.3% participants were injecting drugs for >10 years and reported the maximum prevalence of HCV seropositivity (47.1%, 95% CI: 23.3%-70.8%). In adjusted analyses, being employed compared to unemployed patients [adjusted prevalence ratio (aPR) = 0.59; 95% CI: 0.38-0.89]; graduated patients compared to illiterate patients [aPR = 0.11; 95% CI: 0.02-0.78]; and patients with education up to higher secondary compared to illiterate patients [aPR = 0.64; 95% CI: 0.43-0.94] had significantly lesser HCV seropositivity. A-one year increase in injection use [aPR = 1.07; 95% CI: 1.04-1.10] was associated with 7% higher prevalence of HCV seropositivity. CONCLUSIONS: In this OST center-based study of 268 PWIDs residing in Patna, ~28% of patients were HCV seropositive, which was positively associated with years of injection use, unemployment, and illiteracy. Our findings suggest that OST centers offer an opportunity to reach a high-risk difficult to reach group for HCV infection and thus support the notion of integrating HCV care into the OST or de-addiction centres.

Zika a Vector Borne Disease Detected in Newer States of India Amidst the COVID-19 Pandemic.

Background: During the second wave of the COVID-19 pandemic, outbreaks of Zika were reported from Kerala, Uttar Pradesh, and Maharashtra, India in 2021. The Dengue and Chikungunya negative samples were retrospectively screened to determine the presence of the Zika virus from different geographical regions of India. Methods: During May to October 2021, the clinical samples of 1475 patients, across 13 states and a union territory of India were screened and re-tested for Dengue, Chikungunya and Zika by CDC Trioplex Real time RT-PCR. The Zika rRTPCR positive samples were further screened with anti-Zika IgM and Plaque Reduction Neutralization Test. Next generation sequencing was used for further molecular characterization. Results: The positivity was observed for Zika (67), Dengue (121), and Chikungunya (10) amongst screened cases. The co-infections of Dengue/Chikungunya, Dengue/Zika, and Dengue/Chikungunya/Zika were also observed. All Zika cases were symptomatic with fever (84%) and rash (78%) as major presenting symptoms. Of them, four patients had respiratory distress, one presented with seizures, and one with suspected microcephaly at birth. The Asian Lineage of Zika and all four serotypes of Dengue were found in circulation. Conclusion: Our study indicates the spread of the Zika virus to several states of India and an urgent need to strengthen its surveillance.

Green synthesis, characterization, antimicrobial and cytotoxic effect of silver nanoparticles using arabinoxylan isolated from Kalmegh.

A green synthesis of silver nanoparticles was synthesized by AgNO3 with arabinoxylan, isolated from green stem of Andrographis paniculata (Kalmegh). The synthesized Ag NPs-arabinoxylan conjugates were characterized by UV-vis spectroscopy, FE-SEM, TEM, XRD, TGA, EDX, and Zeta potential experiments. The Ag NPs formation was established by the surface plasmon resonance band ~410.25 nm. SEM image showed mostly spherical morphology of Ag NPs. The fcc crystalline nature was identified by XRD, SAED and the size were 24.5 and 25 nm from TEM and XRD analysis respectively. The prepared Ag NPs showed dose-dependent antimicrobial activity against Streptococcus pneumonia, Candida albicans and E. coli. The nanoparciles damage 4% hemolysis to human RBCs at 12.5 µg/mL. MTT assay of Ag NPs showed that half of the cell killed at 10 µg/mL and wound healing assay observed effective inhibition cell proliferation.

Removal of As(V), Cr(VI) and Cu(II) using novel amine functionalized composite nanofiltration membranes fabricated on ceramic tubular substrate.

Novel amine functionalized composite membranes were prepared over tubular ceramic substrate using facile dip-coating and cross-flow filtration approach. The two fabricated membranes, P-60S and P-60S-EDTA with polyethyleneimine (PEI) and EDTA-modified PEI as functional layers respectively, were characterized in terms of EDX, FTIR, XPS, FESEM, AFM and contact angle analyses which confirmed their stable physical and chemical structure for use in high pressure application. Clean water permeability and MWCO study revealed the superior permeability and rejection efficiency of the P-60S-EDTA compared to the P-60S membrane. Incorporation of bulky EDTA molecules in the membrane functional layer simultaneously decreased pore size and increased membrane hydrophilicity. The removal of As(V), Cr(VI) and Cu(II) heavy metals by both membranes were found to be highly pH dependent and overall rejection improved in case of P-60S-EDTA membrane [99.82% for Cu(II), 96.75% for As(V) and 97.22% for Cr(VI)]. Interestingly, rejection of As(V) and Cr(VI) was significantly improved in presence of Cu(II) due to volume resistance provided by EDTA-Cu(II) complex towards the passage of other heavy metal ions. Excellent stability of P-60S-EDTA membrane in continuous operation of 36 h in both ideal and practical water environment suggests its promising application in real field heavy metal contaminated waste water treatment.

Computational and experimental elucidation of Plasmodium falciparum phosphoethanolamine methyltransferase inhibitors: Pivotal drug target.

INTRODUCTION: Plasmodium falciparum synthesizes phosphatidylcholine for the membrane development through serine decarboxylase-phosphoethanolamine methyltransferase pathway for growth in human host. Phosphoethanolamine-methyltransferase (PfPMT) is a crucial enzyme for the synthesis of phosphocholine which is a precursor for phosphatidylcholine synthesis and is considered as a pivotal drug target as it is absent in the host. The inhibition of PfPMT may kill malaria parasite and hence is being considered as potential target for rational antimalarial drug designing. METHODS: In this study, we have used computer aided drug designing (CADD) approaches to establish potential PfPMT inhibitors from Asinex compound library virtually screened for ADMET and the docking affinity. The selected compounds were tested for in-vitro schizonticidal, gametocidal and cytotoxicity activity. Nontoxic compounds were further studied for PfPMT enzyme specificity and antimalarial efficacy for P. berghei in albino mice model. RESULTS: Our results have identified two nontoxic PfPMT competitive inhibitors ASN.1 and ASN.3 with better schizonticidal and gametocidal activity which were found to inhibit PfPMT at IC50 1.49µM and 2.31µM respectively. The promising reduction in parasitaemia was found both in orally (50 & 10 mg/kg) and intravenous (IV) (5& 1 mg/kg) however, the better growth inhibition was found in intravenous groups. CONCLUSION: We report that the compounds containing Pyridinyl-Pyrimidine and Phenyl-Furan scaffolds as the potential inhibitors of PfPMT and thus may act as promising antimalarial inhibitor candidates which can be further optimized and used as leads for template based antimalarial drug development.

Docking predictions based Plasmodium falciparum phosphoethanolamine methyl transferase inhibitor identification and in-vitro antimalarial activity analysis.

The increased multidrug resistance among antimalarial drugs produces the urgency of potent anti malarial to combat resistant malaria and the malaria burden worldwide. The protein which may prevent the growth or transmission of malaria parasite may be the great target for rational drug designing. Plasmodium falciparum phosphoethanolamine methyltransferase (Pfpmt) absent in human catalyzes triple methylation of ethanolamine into phosphocholine for phosphatidylcholine biosynthesis from serine decarboxylation phosphoethanolamine methyltransferase pathway for the membrane development at asexual as well as sexual stages of parasite. The Plasmodium requires production of membrane rapidly for growth and multiplication. Hence, the phosphoethanolamine methyltransferase of Plasmodium falciparum was selected as drug target for rational drug designing. Using Discovery studio 3.5 software the library of zinc compounds was screened against target and analyzed. The compounds with better druglike properties and docking affinity and binding interaction for target protein were procured for in vitro analysis against Plasmodium falciparum culture (IC50). Compounds ZINC02103914 and ZINC12882412 were found to have good druglike properties and affinity for Pfpmt also inhibited P. falciparum growth at very low µM IC50 concentration 3.0 µM and 2.1 µM respectively also found nontoxic in vitro against HEK-293 cells. Simulation study of best inhibitor revealed the specificity for the target protein. Hence, the compounds possessed the immense probability of being inhibitors of Pfpmt and may be optimized as antimalarial agent for combinational therapy to overcome the multidrug resistance and may also be used as template for optimization and rational drug designing.

Molecular docking studies of chloroquine and its derivatives against P23pro-zbd domain of chikungunya virus: Implication in designing of novel therapeutic strategies.

The arthropod-transmitted chikungunya virus has emerged as an epidemic menace that causes debilitating polyarthritis. With this life-threatening impact on humans, the possible treatment requires to cure the viral infectivity. But, devoid of any vaccine against the chikungunya virus (CHIKV), there is a need to develop a novel chemotherapeutic strategy to treat this noxious infection. CHIKV carries highly compact P23pro-zbd structure that possesses potential RNA-binding surface domains which extremely influences the use of RNA template during genome replication at the time of infection and pathogenesis. Therefore, computational approaches were used to explore the novel small molecule inhibitors targeting P23pro-zbd domain. The tertiary structure was modeled and optimized using in silico approaches. The results obtained from PROCHECK (93.1% residues in favored regions), ERRAT (87.480 overall model quality) and ProSA (Z-score: -11.72) revealed the reliability of the proposed model. Interestingly, a previously reported inhibitor, chloroquine possesses good binding affinities with the target domain. In-depth analysis revealed that chloroquine derivatives such as didesethyl chloroquine hydroxyacetamide, cletoquine, hydroxychloroquine exhibited a better binding affinity. Notably, MD simulation analysis exhibited that Thr1312, Ala1355, Ala1356, Asn1357, Asp1364, Val1366, Cys1367, Ala1401, Gly1403, Ser1443, Tyr1444, Gly1445, Asn1459, and Thr1463 residues are the key amino acid responsible for stable ligand-protein interaction. The results obtained from this study provide new insights and advances the understanding to develop a new approach to consider effective and novel drug against chikungunya. However, a detailed in vivo study is required to explore its drug likeliness against this life-threatening disease.

Iron oxide nanoparticles based antiviral activity of H1N1 influenza A virus.

Influenza virus is a common human pathogenic agent that has caused serious respiratory illness and death over the past century and in recent year. Treatment options against pandemic influenza strain A/H1N1 are very limited and unsatisfactory. Therefore we have developed iron oxide nanoparticles (IO-NPs) with particle size in the range of 10-15 nm against pandemic influenza strain A/H1N1/Eastern India/66/PR8-H1N1. Cell viability and anti-influenza activity was measured by MTT assay, plaque inhibition and quantifying viral transcripts using quantitative real-time PCR with Iron oxide nanoparticles in a dose- and time-dependent manner. 50% cell viability (TD50) was observed at 4.25 pg ± .2 pg of Iron oxide nanoparticles. The percentage of plaque inhibition relative to the infection and the IC50 (50% virus reduction) of PR8-H1N1strain (0.5 moi) were measured in vitro by the plate forming unit (pfu) in MA104 cells. Finding were observed at 01 pg after 72 h. The Antiviral activity determined by change in viral RNA transcripts within 24 h of virus infection by RT-PCR, 08 fold reductions in virus found when treated with Iron oxide nanoparticles Thus; it opens a new avenue for use of IP-NPs against virus infections.

In-silico screening and validation of high-affinity tetra-peptide inhibitor of Leishmania donovani O-acetyl serine sulfhydrylase (OASS).

OASS is a specific enzyme that helps Leishmania parasite to survive the oxidative stress condition in human macrophages. SAT C-terminal peptides in several organisms, including Leishmania, were reported to inhibit or reduce the activity of OASS. Small peptide and small molecules mimicking the SAT C-terminal residues are designed and tested for the inhibition of OASS in different organisms. Hence, in this study, all the possible tetra-peptide combinations were designed and screened based on the docking ability with Leishmania donovani OASS (Ld-OASS). The top ranked peptides were further validated for the stability using 50 ns molecular dynamic simulation. In order to identify the better binding capability of the peptides, the top peptides complexed with Ld-OASS were also subjected to molecular dynamic simulation. The docking and simulation results favored the peptide EWSI to possess greater advantage than previously reported peptide (DWSI) in binding with Ld-OASS active site. Also, screening of non-peptide inhibitor of Asinex Biodesign library based on the shape similarity of EWSI and DWSI was performed. The top similar molecules of each peptides were docked on to Ld-OASS active site and subsequently simulated for 20 ns. The results suggested that the ligand that shares high shape similarity with EWSI possess better binding capability than the ligand that shares high shape similarity with DWSI. This study revealed that the tetra-peptide EWSI had marginal advantage over DWSI in binding with Ld-OASS, thereby providing basis for defining a pharmacophoric scaffold for the design of peptidomimetic inhibitors as well as non-peptide inhibitors of Ld-OASS. Communicated by Ramaswamy H. Sarma.

Acid-Sensing Ion Channels Structural Aspects, Pathophysiological Importance and Experimental Mutational Data Available Across Various Species to Target Human ASIC1.

The H+-gated (proton) currents are widely present in brain sensory neuronal system and various studies identified the structural units and deciphered the physiological and pathological function of ion channels. The normal neuron requires an optimal pH to carry out its functions. In acidosis, the ASICs (Acid-sensing Ion Channels) are activated in both the CNS (central nervous system) and PNS (peripheral nervous system). ASICs are related to degenerin channels (DEGs), epithelial sodium cation channels (ENaCs), and FMRF-amide (Phe-Met-Arg-Phe-NH2)-gated channels (FaNaC). Its activation leads physiologically to pain perception, synaptic plasticity, learning and memory, fear, ischemic neuronal injury, seizure termination, neuronal degeneration, and mechanosensation. It detects the level of acid fluctuation in the extracellular environment and responds to acidic pH by increasing the rate of membrane depolarization. It conducts cations like Na+ (Sodium) and Ca2+ (Calcium) ions across the membrane upon protonation. The ASICs subtypes are characterized by differing biophysical properties and pH sensitivities. The subtype ASIC1 is involved in various CNS diseases and therefore focusing on its specific functional properties will guide in drug design methods. The review highlights the cASIC1 (Chicken ASIC1) crystal structures, involvement in physiological environment and limitations of currently available inhibitors. In addition, it details the mutational data available to design an inhibitor against hASIC1 (Human ASIC1).

The potential HLA Class I-restricted epitopes derived from LeIF and TSA of Leishmania donovani evoke anti-leishmania CD8+ T lymphocyte response.

To explore new protective measure against visceral leishmaniasis, reverse vaccinology approach was employed to identify key immunogenic regions which can mediate long-term immunity. In-depth computational analysis revealed nine promiscuous epitopes which can possibly be presented by 46 human leukocyte antigen, thereby broadening the worldwide population up to 94.16%. This is of reasonable significance that most of the epitopes shared 100% sequence homology with other Leishmania species and could evoke a common pattern of protective immune response. Transporter associated with antigen processing binding affinity, molecular docking approach followed by dynamics simulation and human leukocyte antigen stabilization assay suggested that the best five optimal set of epitopes bind in between α1 and α2 binding groove with sufficient affinity and stability which allows the translocation of intact epitope to the cell surface. Fascinatingly, the human leukocyte antigen stabilization assay exhibited a modest correlation with the positive immunogenicity score predicted by class I pMHC immunogenicity predictor. A support for this notion came from ELISA and FACS analysis where the epitopes as a cocktail induced CD8+ IFN-γ and Granzyme B levels significantly in treated visceral leishmaniasis subject which suggests the immunogenic ability of the selected epitopes.

Noninvasive Sweat-Based Diagnosis of Visceral Leishmaniasis and Post Kala-Azar Dermal Leishmaniasis.

The diagnosis of visceral leishmaniasis (VL) is one of the foremost barriers in the control of this disease, as demonstration of the parasite by splenic/bone marrow aspiration is relatively difficult and requires expertise and laboratory support. The aim of the present study was to find a noninvasive diagnostic approach using the existing recombinant kinesine-39 (rK-39) immunochromatographic nitrocellulose strips test (ICT) with a human sweat specimen for the diagnosis of VL. The investigation was carried out on specimens (blood, sweat, and urine) collected from 58 confirmed VL, 50 confirmed post kala-azar dermal leishmaniasis (PKDL), 36 healthy control, and 35 patients from other diseases. The data obtained from this study reveal that 96.6% clinically confirmed active VL participants were found to be positive when tested against a sweat specimen. Interestingly, the scenario was similar when tested against a blood specimen (96.6% positive by rK-39). Moreover, a test of both sweats and blood specimens from 50 PKDL participants resulted in 100% positivity, whereas no healthy control participants were found to be rK-39 positive. The sensitivity of the rK-39 ICT in sweat specimen was 94.7%, whereas the specificity was 100% in healthy controls from endemic, nonendemic, and other infectious diseases, respectively. No difference was observed in sweat specimen of VL and PKDL cases which signifies its reliability. However, further evaluation of this method on a larger scale could enhance the reliability of the proposed model so that it could be used efficiently in VL management and eradication.

Mining the Proteome of Leishmania donovani for the Development of Novel MHC Class I Restricted Epitope for the Control of Visceral Leishmaniasis.

Although, the precise host defence mechanism(s) is not completely understood, T cell-mediated immune responses is believed to play a pivotal role in controlling parasite infection. Here we target the stage dependent over expressed gene. Here, the consensus based computational approach was adopted for the screening of potential major histocompatibility complex class I restricted epitopes. Based on the computational analysis and previously published report, a set 19 antigenic proteins derived from Leishmania donovani were screened for further characterization as vaccine candidates. A total of 49 epitopes were predicted, which revealed a comprehensive binding affinity to the 40 different MHC class I supertypes. Based on the population coverage and HLA cross presentation, nine highly promiscuous epitopes such as LTYDDVWTV (P1), FLFPQRTAL(P2), FLFSNGAVV (P3), YIYNFGIRV (P4), YMTAAFAAL (P5), KLLRPFAPL (P6), FMLGWIVTI (P7), SLFERNKRV (P8), and SVWNRIFTL (P9) which have either a high or an intermediate TAP binding affinity were selected for further analysis. Theoretical population coverage analysis of polytope vaccine (P1-P9) revealed more than 92% population. Stimulation with the cocktail of peptide revealed a proliferative CD8+ T cell response and increased IFN-γ production. An upregulated NF-κB activity is thought to be play a pivotal role in T cell proliferation against the selected peptide. The Th1-type cytokine profile (presence of IFN-γ and absence of IL-10) suggests the potentiality of the cocktail of epitope as a subunit vaccine against leishmaniasis. However, the efficiency of these epitopes to trigger other Th1 cytokines and chemokines in a humanized mice model could explore its plausibility as a vaccine candidate. J. Cell. Biochem. 119: 378-391, 2018. © 2017 Wiley Periodicals, Inc.

Computational elucidation, mutational and hot spot-based designing of potential inhibitors against human acid-sensing ion channels (hASIC-1a) to treat various physiological conditions.

Acid-sensing ion channels are ligand/proton-gated ion channels belonging to the family of the degenerin/epithelial Na+ channel (DEG/ENaC). They function as a sodium-selective pore for Ca2+ entry into neuronal cells during pathological conditions. The blocking of this channel has therapeutic importance, because at basal physiological pH (7.2), it is in a closed state and under a more acidic condition, and the ASIC1a ion channel is activated. To investigate the different states of the hASIC1a channel based on mutational analysis, structure-based virtual screening and molecular dynamics simulation studies. The system showed stability after 30 ns (after 1500 frame), and it was stabilized to an average value around 2.2Å. During the simulation, the ion channel residues in persistent contact with toxin PcTx1 were D237, E238, D347, D351, E219 and E355. These residues are important physiologically for the activation of the channel. From in silico alanine scanning, the significant hotspots obtained in hASIC1 are E344, P347, F352, D351, E355 and E219. From the sitemap analysis, it was evident that the sitemap found one of the active sites at the PcTx1 binding site with a site score of 1.086 and a D-score of 1.035 for hASIC1. We obtained a few promising hits and final potential hits from the virtual screening in hASIC1 that made interactions with the residues in the acidic pocket (E344, P347, F352, D351, E355 and E219). Based on these studies, the hits and scaffolds of potential therapeutic interest against various pathological conditions are associated with hASIC1a for future studies.