Integrative Multiomics and Regulatory Network Analyses Uncovers the Role of OAS3, TRAFD1, miR-222-3p, and miR-125b-5p in Hepatitis E Virus Infection.

The hepatitis E virus (HEV) is a long-ignored virus that has spread globally with time. It ranked 6th among the top risk-ranking viruses with high zoonotic spillover potential; thus, considering its viral threats is a pressing priority. The molecular pathophysiology of HEV infection or the underlying cause is limited. Therefore, we incorporated an unbiased, systematic methodology to get insights into the biological heterogeneity associated with the HEV. Our study fetched 93 and 2016 differentially expressed genes (DEGs) from chronic HEV (CHEV) infection in kidney-transplant patients, followed by hub module selection from a weighted gene co-expression network (WGCN). Most of the hub genes identified in this study were associated with interferon (IFN) signaling pathways. Amongst the genes induced by IFNs, the 2'-5'-oligoadenylate synthase 3 (OAS3) protein was upregulated. Protein-protein interaction (PPI) modular, functional enrichment, and feed-forward loop (FFL) analyses led to the identification of two key miRNAs, i.e., miR-222-3p and miR-125b-5p, which showed a strong association with the OAS3 gene and TRAF-type zinc finger domain containing 1 (TRAFD1) transcription factor (TF) based on essential centrality measures. Further experimental studies are required to substantiate the significance of these FFL-associated genes and miRNAs with their respective functions in CHEV. To our knowledge, it is the first time that miR-222-3p has been described as a reference miRNA for use in CHEV sample analyses. In conclusion, our study has enlightened a few budding targets of HEV, which might help us understand the cellular and molecular pathways dysregulated in HEV through various factors. Thus, providing a novel insight into its pathophysiology and progression dynamics.

Targeting Natural Plant Metabolites for Hunting SARS-CoV-2 Omicron BA.1 Variant Inhibitors: Extraction, Molecular Docking, Molecular Dynamics, and Physicochemical Properties Study.

(1) Background: SARS-CoV-2 Omicron BA.1 is the most common variation found in most countries and is responsible for 99% of cases in the United States. To overcome this challenge, there is an urgent need to discover effective inhibitors to prevent the emerging BA.1 variant. Natural products, particularly flavonoids, have had widespread success in reducing COVID-19 prevalence. (2) Methods: In the ongoing study, fifteen compounds were annotated from Echium angustifolium and peach (Prunus persica), which were computationally analyzed using various in silico techniques. Molecular docking calculations were performed for the identified phytochemicals to investigate their efficacy. Molecular dynamics (MD) simulations over 200 ns followed by molecular mechanics Poisson-Boltzmann surface area calculations (MM/PBSA) were performed to estimate the binding energy. Bioactivity was also calculated for the best components in terms of drug likeness and drug score. (3) Results: The data obtained from the molecular docking study demonstrated that five compounds exhibited remarkable potency, with docking scores greater than -9.0 kcal/mol. Among them, compounds 1, 2 and 4 showed higher stability within the active site of Omicron BA.1, with ΔGbinding values of -49.02, -48.07, and -67.47 KJ/mol, respectively. These findings imply that the discovered phytoconstituents are promising in the search for anti-Omicron BA.1 drugs and should be investigated in future in vitro and in vivo research.

Therapeutic Potential of Myrrh, a Natural Resin, in Health Management through Modulation of Oxidative Stress, Inflammation, and Advanced Glycation End Products Formation Using In Vitro and In Silico Analysis

Oxidative stress, hyper-inflammatory responses, and protein glycation are the chief contributing factors in the pathogenesis of several diseases. This study aimed to explore the therapeutic role of myrrh in health management through in vitro and in silico studies. Antioxidant potential, anti-inflammatory potential, antiglycation, and advanced glycation end products (AGEs) formation inhibition activities were determined by various in vitro assays. Molecular docking was performed to predict the non-covalent binding of macromolecules (receptor) and a small molecule (ligand). Myrrh extract contained significant antioxidant activity as reflected by FRAP value (16.12 µg ascorbic acid/100 mg dry weight), the maximum percentage of DPPH scavenging (57.71%), and maximum hydrogen peroxide reducing activity (58.71%) at a concentration of 600 µg/mL. Further, the extract exhibited maximum protection from bovine serum albumin (BSA) denaturation inhibition (53.47%), anti-proteinase action (43.517%), and egg albumin denaturation inhibition (44.95%) at a dose of 600 µg/mL concentration. Myrrh is used in pharmacy as an antiseptic, anti-inflammatory, antimicrobial, antifungal, and anti-venom remedy. This study aimed to explore the antioxidant, anti-inflammatory, antiarthritic, antiglycation, and advanced glycation end products (AGEs) formation inhibition ability of methanolic myrrh extract. It was found that myrrh has good antioxidant potential due to plenty of flavonoids and polyphenolic compounds, as reflected by results of the 2,2′-diphenyl-1-picrylhydrazyl radical (DPPH) assay, FRAP (ferric reducing antioxidant power) test, and hydrogen peroxide reducing test. Furthermore, myrrh methanolic extract was found to be significantly effective against heat-induced albumin denaturation, and percent inhibition of denaturation increases with increased extract concentration. The presence of myrrh extract at a dose of 600 μg/mL decreased browning intensity (59.38%), percent aggregation index (59.88%), and percentage amyloid structure (56.13%). We used molecular docking tools to study the role of myrrh in oxidative stress (Catalase), antioxidant property (Superoxide dismutase), and antiviral property (spike protein S). The molecular docking analysis confirmed four phytoconstituents;2,3-Furandione, Curzerene, delta-Elemene, and Furanoeudesma-1,3-Diene interact with catalase and superoxide dismutase. Curzerene and Furanoeudesma-1,3-Diene showed remarkable interaction with SARS-CoV-2 spike protein S. Our data suggest that myrrh resin extract can be used to develop a suitable alternative therapy for various diseases linked with oxidative stress, inflammation, glycation, and AGEs.

Clinical Characteristics, Outcomes and Prognostic Factors for Critical Illness in Hospitalized COVID-19 Patients in Saudi Arabia: A Retrospective Cohort Study.

Background: A good understanding of the possible risk factors for coronavirus disease 19 (COVID-19) severity could help clinicians in identifying patients who need prioritized treatment to prevent disease progression and adverse outcome. In the present study, we aimed to correlate clinical and laboratory characteristics of hospitalized COVID-19 patients to disease outcome in Saudi Arabia. Materials and Methods: The present study included 199 COVID-19 patients admitted to King Fahd Specialist Hospital, Buraydah, Qassim, Saudi Arabia, from April to December 2020. Patients were followed-up until discharge either for recovery or death. Demographic data, clinical data and laboratory results were retrieved from electronic patient records. Results: Critical COVID-19 cases showed higher mean of age and higher prevalence of co-morbid conditions. Fifty-five patients died during the observation period. Risk factors for in hospital death for COVID 19 patients were leukocytosis (OR 1.89, 95% CI 1.008-3.548, p = 0.081), lymphocytopenia (OR 2.152, 95% CI 1.079-4.295, p = 0.020), neutrophilia (OR 1.839, 95% CI 0.951-3.55, p = 0.047), thrombocytopenia (OR 2.152, 95% CI 0.852-5.430, p = 0.085), liver injury (OR 2.689, 95% CI 1.373-4.944, p = 0.003), acute kidney injury (OR 1.248, 95% CI 0.631-2.467 p = 0.319), pancreatic injury (OR 1.973, 95% CI 0.939-4.144, p = 0.056) and high D dimer (OR 2.635, 95% CI 0.747-9.287, p = 0.091). Conclusion: Clinical and laboratory data of COVID-19 patients may help understanding the pathogenesis of the disease and subsequently improve of the outcome of patients by determination of the associated risk factors and recognition of high risk group who are more liable for complications and in hospital death. The present study put an eye on some parameters (laboratory and clinical) that should be alarming signs that the patient is at high risk bad prognosis.

Encapsulation of MERS antigen into α-GalCer-bearing-liposomes elicits stronger effector and memory immune responses in immunocompetent and leukopenic mice.

Objectives: Here, we prepared a liposome-based vaccine formulation containing Middle East Respiratory Syndrome Coronavirus papain-like protease (MERS-CoV-PLpro). Methods: A persistent leukopenic condition was induced in mice by injecting cyclophosphamide (CYP) three days before each dose of immunization. Mice were immunized on days 0, 14 and 21 with α-GalCer-bearing MERS-CoV PLpro-encapsulated DPPC-liposomes (α-GalCer-MERS-PLpro-liposomes or MERS-CoV PLpo-encapsulated DPPC-liposomes (MERS-PLpro-liposomes), whereas the antigen emulsified in Alum (MERS-PLpro-Alum) was taken as a control. On day 26, the blood was taken from the immunized mice to analyze IgG titer, whereas the splenocytes were used to analyze the lymphocyte proliferation and the level of cytokines. In order to assess the memory immune response, mice were given a booster dose after 150 days of the last immunization. Results: The higher levels of MERS-CoV-PLpro-specific antibody titer, IgG2a and lymphocyte proliferation were noticed in mice immunized with α-GalCer-MERS-PLpro-liposomes. Besides, the splenocytes from mice immunized with α-GalCer-MERS-PLpro-liposomes produced larger amounts of IFN-γ as compared to the splenocytes from MERS-PLpro-liposomes or MERS- PLpro-Alum immunized mice. Importantly, an efficient antigen-specific memory immune response was observed in α-GalCer-MERS-PLpro-liposomes immunized mice. Conclusions: These findings suggest that α-GalCer-MERS-PLpro-liposomes may substantiate to be a successful vaccine formulation against MERS-CoV infection, particularly in immunocompromised individuals.

Synthesis of indole-based oxadiazoles and their interaction with bacterial peptidoglycan and SARS-CoV-2 main protease: In vitro, molecular docking and in silico ADME/Tox study

In the present study, Indole-based-oxadiazole (1A-17A) compounds were successfully synthesized. The structures of all synthesized compounds were fully characterized by different sophisticated spectroscopic techniques such 1H NMR, 13C NMR, EI-MS and HREI-MS. Further, the synthesized compounds were explored to investigate their broad-spectrum antibacterial and antibiofilm potential against multidrug resistant Pseudomonas aeruginosa (MDR-PA) and methicillin resistant Staphylococcus aureus (MRSA). The compounds possessed a broad spectrum of antibacterial activity having MIC values of values 1-8 mg/ml against the tested microorganisms. Compound A6 and A7 shows maximum antibacterial activity against MDR-PA, whereas A6, A7 and A11 shows highest activity against MRSA. Furthermore, antibiofilm assay shows that A6, A7 and A11 showed maximum inhibition of biofilm formation and it was found that at 4 mg/ml;A6, A7 and A11 inhibit MRSA biofilm formation by 81.1, 77.5 and 75.9%, respectively;whereas in case of P. aeruginosa;A6 and A7 showed maximum biofilm inhibition and inhibit biofilm formation by 81.5 and 73.7%, respectively. Molecular docking study showed that compounds A6, A7, A8, A10, and A11 had high binding affinity to bacterial peptidoglycan, indicating their potential inhibitory activity against tested bacteria, whereas A6 and A11 were found to be the most effective inhibitors of SARS CoV-2 main protease (3CLpro), with a binding affinity of −7.78 kcal/mol. Furthermore, SwissADME and pkCSM-pharmacokinetics online tools was applied to calculate the ADME/Tox profile of the synthesized compounds and the toxicity of these chemicals was found to be low. The Lipinski, Veber, Ghose, and Consensus LogP criteria were also used to predict drug-likeness levels of the compounds. Our findings imply that the synthesized compounds could be a useful for the preventing and treating biofilm-related microbial infection as well as SARS-CoV2 infections.

Role of Ajwa Date Fruit Pulp and Seed in the Management of Diseases through In Vitro and In Silico Analysis.

This study investigated the health-promoting activities of methanolic extracts of Ajwa date seed and fruit pulp extracts through in vitro studies. These studies confirmed potential antioxidant, anti-hemolytic, anti-proteolytic, and anti-bacterial activities associated with Ajwa dates. The EC50 values of fruit pulp and seed extracts in methanol were reported to be 1580.35 ± 0.37 and 1272.68 ± 0.27 µg/mL, respectively, in the DPPH test. The maximum percentage of hydrogen peroxide-reducing activity was 71.3 and 65.38% for both extracts at 600 µg/mL. Fruit pulp and seed extracts inhibited heat-induced BSA denaturation by 68.11 and 60.308%, heat-induced hemolysis by 63.84% and 58.10%, and hypersalinity-induced hemolysis by 61.71% and 57.27%, and showed the maximum anti-proteinase potential of 56.8 and 51.31% at 600 µg/mL, respectively. Seed and fruit pulp inhibited heat-induced egg albumin denaturation at the same concentration by 44.31 and 50.84%, respectively. Ajwa seed showed minimum browning intensity by 63.2%, percent aggregation index by 64.2%, and amyloid structure by 63.8% at 600 µg/mL. At 100 mg/mL, Ajwa seed extract exhibited good antibacterial activity. Molecular docking analysis showed that ten active constituents of Ajwa seeds bind with the critical antioxidant enzymes, catalase (1DGH) and superoxide dismutase (5YTU). The functional residues involved in such interactions include Arg72, Ala357, and Leu144 in 1DGH, and Gly37, Pro13, and Asp11 in 5YTU. Hence, Ajwa dates can be used to develop a suitable alternative therapy in various diseases, including diabetes and possibly COVID-19-associated complications.

TAT-peptide conjugated repurposing drug against SARS-CoV-2 main protease (3CLpro): Potential therapeutic intervention to combat COVID-19.

The Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that originated in Chinese city of Wuhan has caused around 906,092 deaths and 28,040,853 confirmed cases worldwide (https://covid19.who.int/, 11 September 2020). In a life-threatening situation, where there is no specific and licensed anti-COVID-19 vaccine or medicine available; the repurposed drug might act as a silver bullet. Currently, more than 211 vaccines, 80 antibodies, 31 antiviral drugs, 35 cell-based, 6 RNA-based and 131 other drugs are in clinical trials. It is therefore utter need of the hour to develop an effective drug that can be used for the treatment of COVID-19 before a vaccine can be developed. One of the best-characterized and attractive drug targets among coronaviruses is the main protease (3CLpro). Therefore, the current study focuses on the molecular docking analysis of TAT-peptide47-57 (GRKKRRQRRRP)-conjugated repurposed drugs (i.e., lopinavir, ritonavir, favipiravir, and hydroxychloroquine) with SARS-CoV-2 main protease (3CLpro) to discover potential efficacy of TAT-peptide (TP) - conjugated repurposing drugs against SARS-CoV-2. The molecular docking results validated that TP-conjugated ritonavir, lopinavir, favipiravir, and hydroxychloroquine have superior and significantly enhanced interactions with the target SARS-CoV-2 main protease. In-silico approach employed in this study suggests that the combination of the drug with TP is an excelling alternative to develop a novel drug for the treatment of SARS-CoV-2 infected patients. The development of TP based delivery of repurposing drugs might be an excellent approach to enhance the efficacy of the existing drugs for the treatment of COVID-19. The predictions from the results obtained provide invaluable information that can be utilized for the choice of candidate drugs for in vitro, in vivo and clinical trials. The outcome from this work prove crucial for exploring and developing novel cost-effective and biocompatible TP conjugated anti-SARS-CoV-2 therapeutic agents in immediate future.

Insights into the Binding of Receptor-Binding Domain (RBD) of SARS-CoV-2 Wild Type and B.1.620 Variant with hACE2 Using Molecular Docking and Simulation Approaches.

Recently, a new variant, B.1620, with mutations (S477N-E484K) in the spike protein's receptor-binding domain (RBD) has been reported in Europe. In order to design therapeutic strategies suitable for B.1.620, further studies are required. A detailed investigation of the structural features and variations caused by these substitutions, that is, a molecular level investigation, is essential to uncover the role of these changes. To determine whether and how the binding affinity of ACE2-RBD is affected, we used protein-protein docking and all-atom simulation approaches. Our analysis revealed that B.1.620 binds more strongly than the wild type and alters the hydrogen bonding network. The docking score for the wild type was reported to be -122.6 +/- 0.7 kcal/mol, while for B.1.620, the docking score was -124.9 +/- 3.8 kcal/mol. A comparative binding investigation showed that the wild-type complex has 11 hydrogen bonds and one salt bridge, while the B.1.620 complex has 14 hydrogen bonds and one salt bridge, among which most of the interactions are preserved between the wild type and B.1.620. A dynamic analysis of the two complexes revealed stable dynamics, which corroborated the global stability trend, compactness, and flexibility of the three essential loops, providing a better conformational optimization opportunity and binding. Furthermore, binding free energy revealed that the wild type had a total binding energy of -51.14 kcal/mol, while for B.1.628, the total binding energy was -68.25 kcal/mol. The current findings based on protein complex modeling and bio-simulation methods revealed the atomic features of the B.1.620 variant harboring S477N and E484K mutations in the RBD and the basis for infectivity. In conclusion, the current study presents distinguishing features of B.1.620, which can be used to design structure-based drugs against the B.1.620 variant.

Manifestations of renal system involvement in hospitalized patients with COVID-19 in Saudi Arabia.

BACKGROUND: Although COVID-19 is an acute disease that usually resolves rapidly in most cases, the disease can be fatal and has a mortality rate of about 1% to 56%. Alveolar injury and respiratory failure are the main causes of death in patients with COVID 19. In addition, the effect of the disease on other organs is not fully understood. Renal system affection has been reported in patients with COVID 19 and is associated with a higher rate of diverse outcomes, including mortality. Therefore, in the present work, we reported the clinical characteristics and laboratory data of hospitalized patients with COVID-19 and analyzed the manifestations that indicated renal system involvement and their impact on clinical outcomes. MATERIALS AND METHODS: This was an observational retrospective study conducted at King Fahd Specialist Hospital, Buraydah, Saudi Arabia. All patients with COVID-19 who were admitted to this Hospital from April to December 2020 were included in the study. The patients' findings at presentation were recorded. Demographic data and laboratory results (hematuria, proteinuria, urinary sediment cast and pus cell presence, and kidney function tests) were retrieved from electronic patient records. RESULTS: One hundred and ninety-three patients with confirmed COVID 19 were included in the study. Dipstick examinations of all urine samples showed proteinuria and hematuria in 53.9% and 22.3% of patients, respectively, whereas microscopic examination revealed the presence of pus and brown muddy granular casts in 33.7% and 12.4% of samples, respectively. Acute kidney injury was reported in 23.3% of patients. A multivariable analysis demonstrated that hematuria was associated with acute kidney injury (AKI) (OR, 2.4; 95% CI, 1.2-4.9; P = 0.001), ICU admission (OR, 3.789; 95% CI, 1.913-7.505; P = 0.003), and mortality (OR, 8.084; 95% CI, 3.756-17.397; P = 0.002). Conversely, proteinuria was less significantly associated with the risk of AKI (OR, 1.56; 95% CI, 1.91-7.50; P = 0.003), ICU admission (OR, 2.493; 95% CI, 1.25-4.72; P = 0.001), and mortality (OR, 2.764; 95% CI, 1.368-5.121; P = 0.003). Patients with AKI had a higher probability for mortality than did those without AKI (OR, 14.208; 95% CI, 6.434-31.375; P = 0.003). CONCLUSION: The manifestations of the involvement of the renal system are not uncommon in COVID-19. These manifestations included proteinuria, hematuria, and AKI and were usually associated with a poor prognosis, including high incidences of both ICU admission and mortality.

Therapeutic development by repurposing drugs targeting SARS-CoV-2 spike protein interactions by simulation studies.

The human-to-human transmitted respiratory illness in COVID-19 affected by the pathogenic Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2), which appeared in the last of December 2019 in Wuhan, China, and rapidly spread in many countries. Thereon, based on the urgent need for therapeutic molecules, we conducted in silico based docking and simulation molecular interaction studies on repurposing drugs, targeting SARS-CoV-2 spike protein. Further, the best binding energy of doxorubicin interacting with virus spike protein (PDB: 6VYB) was observed to be -6.38 kcal/mol and it was followed by exemestane and gatifloxacin. The molecular simulation dynamics analysis of doxorubicin, Reference Mean Square Deviation (RMSD), Root Mean Square fluctuation (RMSF), Radius of Gyration (Rg), and formation of hydrogen bonds plot interpretation suggested, a significant deviation and fluctuation of Doxorubicin-Spike RBD complex during the whole simulation period. The Rg analysis has stated that the Doxorubicin-Spike RBD complex was stable during 15,000-35,000 ps MDS. The results have suggested that doxorubicin could inhibit the virus spike protein and prevent the access of the SARS-CoV-2 to the host cell. Thus, in-vitro/in-vivo research on these drugs could be advantageous to evaluate significant molecules that control the COVID-19 disease.

Natural Products and Nutrients against Different Viral Diseases: Prospects in Prevention and Treatment of SARS-CoV-2.

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has caused a global pandemic and is posing a serious challenge to mankind. As per the current scenario, there is an urgent need for antiviral that could act as a protective and therapeutic against SARS-CoV-2. Previous studies have shown that SARS-CoV-2 is much similar to the SARS-CoV bat that occurred in 2002-03. Since it is a zoonotic virus, the exact source is still unknown, but it is believed bats may be the primary reservoir of SARS-CoV-2 through which it has been transferred to humans. In this review, we have tried to summarize some of the approaches that could be effective against SARS-CoV-2. Firstly, plants or plant-based products have been effective against different viral diseases, and secondly, plants or plant-based natural products have the minimum adverse effect. We have also highlighted a few vitamins and minerals that could be beneficial against SARS-CoV-2.

Novel Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV2) and Other Coronaviruses: A Genome-wide Comparative Annotation and Analysis.

Novel strain of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV2) causes mild to severe respiratory illness. The early symptoms may be fever, dry cough, sour throat, and difficulty in breathing which may lead to death in severe cases. Compared to previous outbreaks like SARS-CoV and Middle East Respiratory Syndrome (MERS), SARS-CoV2 disease (COVID-19) outbreak has been much distressing due to its high rate of infection but low infection fatality rate (IFR) with 1.4% around the world. World Health Organization (WHO) has declared (COVID-19) a pandemic on March 11, 2020. In the month of January 2020, the whole genome of SARS-CoV2 was sequenced which made work easy for researchers to develop diagnostic kits and to carry out drug repurposing to effectively alleviate the pandemic situation in the world. Now, it is important to understand why this virus has high rate of infectivity or is there any factor involved at the genome level which actually facilitates this virus infection globally? In this study, we have extensively analyzed the whole genomes of different coronaviruses infecting humans and animals in different geographical locations around the world. The main aim of the study is to identify the similarity and the mutational adaptation of the coronaviruses from different host and geographical locations to the SARS-CoV2 and provide a better strategy to understand the mutational rate for specific target-based drug designing. This study is focused to every annotation in a comparative manner which includes SNPs, repeat analysis with the different categorization of the short-sequence repeats and long-sequence repeats, different UTR's, transcriptional factors, and the predicted matured peptides with the specific length and positions on the genomes. The extensive analysis on SNPs revealed that Wuhan SARS-CoV2 and Indian SARS-CoV2 are having only eight SNPs. Collectively, phylogenetic analysis, repeat analysis, and the polymorphism revealed the genomic conserveness within the SARS-CoV2 and few other coronaviruses with very less mutational chances and the huge distance and mutations from the few other species.

SARS-CoV-2: An Update on Genomics, Risk Assessment, Potential Therapeutics and Vaccine Development.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a great threat to public health, being a causative pathogen of a deadly coronavirus disease (COVID-19). It has spread to more than 200 countries and infected millions of individuals globally. Although SARS-CoV-2 has structural/genomic similarities with the previously reported SARS-CoV and MERS-CoV, the specific mutations in its genome make it a novel virus. Available therapeutic strategies failed to control this virus. Despite strict standard operating procedures (SOPs), SARS-CoV-2 has spread globally and it is mutating gradually as well. Diligent efforts, special care, and awareness are needed to reduce transmission among susceptible masses particularly elder people, children, and health care workers. In this review, we highlighted the basic genome organization and structure of SARS-CoV-2. Its transmission dynamics, symptoms, and associated risk factors are discussed. This review also presents the latest mutations identified in its genome, the potential therapeutic options being used, and a brief explanation of vaccine development efforts against COVID-19. The effort will not only help readers to understand the deadly SARS-CoV-2 virus but also provide updated information to researchers for their research work.

In Silico Evaluation of Prospective Anti-COVID-19 Drug Candidates as Potential SARS-CoV-2 Main Protease Inhibitors.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a recently emanating human infectious coronavirus that causes COVID-19 disease. On 11th March 2020, it has been announced as a pandemic by the World Health Organization (WHO). Recently, several repositioned drugs have been subjected to clinical investigations as anti-COVID-19 drugs. Here, in silico drug discovery tools were utilized to evaluate the binding affinities and features of eighteen anti-COVID-19 drug candidates against SARS-CoV-2 main protease (Mpro). Molecular docking calculations using Autodock Vina showed considerable binding affinities of the investigated drugs with docking scores ranging from - 5.3 to - 8.3 kcal/mol, with higher binding affinities for HIV drugs compared to the other antiviral drugs. Molecular dynamics (MD) simulations were performed for the predicted drug-Mpro complexes for 50 ns, followed by binding energy calculations utilizing molecular mechanics-generalized Born surface area (MM-GBSA) approach. MM-GBSA calculations demonstrated promising binding affinities of TMC-310911 and ritonavir towards SARS-CoV-2 Mpro, with binding energy values of - 52.8 and - 49.4 kcal/mol, respectively. Surpass potentialities of TMC-310911 and ritonavir are returned to their capabilities of forming multiple hydrogen bonds with the proximal amino acids inside Mpro's binding site. Structural and energetic analyses involving root-mean-square deviation, binding energy per-frame, center-of-mass distance, and hydrogen bond length demonstrated the stability of TMC-310911 and ritonavir inside the Mpro's active site over the 50 ns MD simulation. This study sheds light on HIV protease drugs as prospective SARS-CoV-2 Mpro inhibitors.

COVID-19: The Emerging Immunopathological Determinants for Recovery or Death.

Hyperactivation of the host immune system during infection by SARS-CoV-2 is the leading cause of death in COVID-19 patients. It is also evident that patients who develop mild/moderate symptoms and successfully recover display functional and well-regulated immune response. Whereas a delayed initial interferon response is associated with severe disease outcome and can be the tipping point towards immunopathological deterioration, often preceding death in COVID-19 patients. Further, adaptive immune response during COVID-19 is heterogeneous and poorly understood. At the same time, some studies suggest activated T and B cell response in severe and critically ill patients and the presence of SARS-CoV2-specific antibodies. Thus, understanding this problem and the underlying molecular pathways implicated in host immune function/dysfunction is imperative to devise effective therapeutic interventions. In this comprehensive review, we discuss the emerging immunopathological determinants and the mechanism of virus evasion by the host cell immune system. Using the knowledge gained from previous respiratory viruses and the emerging clinical and molecular findings on SARS-CoV-2, we have tried to provide a holistic understanding of the host innate and adaptive immune response that may determine disease outcome. Considering the critical role of the adaptive immune system during the viral clearance, we have presented the molecular insights of the plausible mechanisms involved in impaired T cell function/dysfunction during various stages of COVID-19.