ABSTRACT
Insights into host-virus interactions during SARS-CoV-2 infection are needed to understand COVID-19 pathogenesis and may help to guide the design of novel antiviral therapeutics. N 6-Methyladenosine modification (m6A), one of the most abundant cellular RNA modifications, regulates key processes in RNA metabolism during stress response. Gene expression profiles observed postinfection with different SARS-CoV-2 variants show changes in the expression of genes related to RNA catabolism, including m6A readers and erasers. We found that infection with SARS-CoV-2 variants causes a loss of m6A in cellular RNAs, whereas m6A is detected abundantly in viral RNA. METTL3, the m6A methyltransferase, shows an unusual cytoplasmic localization postinfection. The B.1.351 variant has a less-pronounced effect on METTL3 localization and loss of m6A than did the B.1 and B.1.1.7 variants. We also observed a loss of m6A upon SARS-CoV-2 infection in air/liquid interface cultures of human airway epithelia, confirming that m6A loss is characteristic of SARS-CoV-2-infected cells. Further, transcripts with m6A modification are preferentially down-regulated postinfection. Inhibition of the export protein XPO1 results in the restoration of METTL3 localization, recovery of m6A on cellular RNA, and increased mRNA expression. Stress granule formation, which is compromised by SARS-CoV-2 infection, is restored by XPO1 inhibition and accompanied by a reduced viral infection in vitro. Together, our study elucidates how SARS-CoV-2 inhibits the stress response and perturbs cellular gene expression in an m6A-dependent manner.
Subject(s)
COVID-19 , SARS-CoV-2 , Humans , SARS-CoV-2/genetics , COVID-19/genetics , Methylation , RNA , RNA, Viral/genetics , Methyltransferases/geneticsABSTRACT
The global coronavirus pandemic has burdened the human population with mass fatalities and disastrous socio-economic consequences. The frequent occurrence of these new variants has fueled the already prevailing challenge. There is still a necessity for highly effective small molecular agents to prevent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Here, we targeted the human transmembrane surface protease TMPRSS2, which is essential for proteolytic activation of SARS-CoV-2. Camostat is a well-known inhibitor of serine proteases and an effective TMPRSS2 inhibitor. A virtual library of camostat-like compounds was computationally screened against the catalytic site of TMPRSS2. Following a sequential in-depth molecular docking and dynamics simulation, we report the compounds that exhibited promising efficacy against TMPRSS2. The molecular docking and MM/PBSA free energy calculation study indicates these compounds carry excellent binding affinity against TMPRSS2 and found them more effective than camostat. The study will open doors for the effective treatment of coronavirus disease 2019.
ABSTRACT
The recent emergence of novel SARS-CoV-2 variants has threatened the efforts to contain the COVID-19 pandemic. The emergence of these "variants of concern" has increased immune escape and has supplanted the ancestral strains. The novel variants harbored by the B.1.617 lineage (kappa and delta) carry mutations within the receptor-binding domain of spike (S) protein (L452R + E484Q and L452R + T478K), the region binding to the host receptor. The double mutations carried by these novel variants are primarily responsible for an upsurge number of COVID-19 cases in India. In this study, we thoroughly investigated the impact of these double mutations on the binding capability to the human host receptor. We performed several structural analyses and found that the studied double mutations increase the binding affinity of the spike protein to the human host receptor (ACE2). Furthermore, our study showed that these double mutants might be a dominant contributor enhancing the receptor-binding affinity of SARS-CoV-2 and consequently making it more stable. We also investigated the impact of these mutations on the binding affinity of two monoclonal antibodies (Abs) (2-15 and LY-CoV555) and found that the presence of the double mutations also hinders its binding with the studied Abs. The principal component analysis, free energy landscape, intermolecular interaction, and other investigations provided a deeper structural insight to better understand the molecular mechanism responsible for increased viral transmissibility of these variants.
Subject(s)
Angiotensin-Converting Enzyme 2/chemistry , COVID-19/virology , Molecular Dynamics Simulation , SARS-CoV-2/chemistry , Spike Glycoprotein, Coronavirus/chemistry , Angiotensin-Converting Enzyme 2/immunology , Antibodies, Monoclonal, Humanized/immunology , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Binding Sites , COVID-19/immunology , COVID-19/transmission , Humans , India , Mutation , Protein Binding , Protein Conformation , SARS-CoV-2/genetics , SARS-CoV-2/immunology , SARS-CoV-2/pathogenicity , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunologyABSTRACT
The COVID-19 outbreak continues to spread worldwide at a rapid rate. Currently, the absence of any effective antiviral treatment is the major concern for the global population. The reports of the occurrence of various point mutations within the important therapeutic target protein of SARS-CoV-2 has elevated the problem. The SARS-CoV-2 main protease (Mpro) is a major therapeutic target for new antiviral designs. In this study, the efficacy of PF-00835231 was investigated (a Mpro inhibitor under clinical trials) against the Mpro and their reported mutants. Various in silico approaches were used to investigate and compare the efficacy of PF-00835231 and five drugs previously documented to inhibit the Mpro. Our study shows that PF-00835231 is not only effective against the wild type but demonstrates a high affinity against the studied mutants as well.
Subject(s)
Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Coronavirus 3C Proteases/antagonists & inhibitors , Indoles/chemistry , Indoles/pharmacology , Leucine/chemistry , Leucine/pharmacology , Protease Inhibitors/chemistry , Protease Inhibitors/pharmacology , Pyrrolidinones/chemistry , Pyrrolidinones/pharmacology , Binding Sites , Computer Simulation , Coronavirus 3C Proteases/chemistry , Coronavirus 3C Proteases/genetics , Databases, Protein , Diarylquinolines/chemistry , Diarylquinolines/pharmacology , Dihydropyridines/chemistry , Dihydropyridines/pharmacology , Humans , Ligands , Molecular Docking Simulation , Molecular Dynamics Simulation , Nitrobenzenes/chemistry , Nitrobenzenes/pharmacology , Nitrophenols/chemistry , Nitrophenols/pharmacology , Organophosphorus Compounds/chemistry , Organophosphorus Compounds/pharmacology , Piperazines/chemistry , Piperazines/pharmacology , Proline/analogs & derivatives , Proline/chemistry , Proline/pharmacology , SARS-CoV-2/drug effects , SARS-CoV-2/genetics , COVID-19 Drug TreatmentABSTRACT
SARS-CoV-2, previously named 2019 novel coronavirus (2019-nCoV), has been associated with the global pandemic of acute respiratory distress syndrome. First reported in December 2019 in the Wuhan province of China, this new RNA virus has several folds higher transmission among humans than its other family member (SARS-CoV and MERS-CoV). The SARS-CoV-2 spike receptor-binding domain (RBD) is the region mediating the binding of the virus to host cells via Angiotensin-converting enzyme 2 (ACE2), a critical step of viral. Here in this study, we have utilized in silico approach for the virtual screening of antiviral library extracted from the Asinex database against the Receptor binding domain (RBD) of the S1 subunit of the SARS-CoV-2 spike glycoprotein. Further, the molecules were ranked based on their binding affinity against RBD, and the top 15 molecules were selected. The affinity of these selected molecules to interrupt the ACE2-Spike interaction was also studied. It was found that the chosen molecules were demonstrating excellent binding affinity against spike protein, and these molecules were also very effectively interrupting the ACE2-RBD interaction. Furthermore, molecular dynamics (MD) simulation studies were utilized to investigate the top 3 selected molecules' stability in the ACE2-RBD complexes. To the best of our knowledge, this is the first study where molecules' inhibitory potential against the Receptor binding domain (RBD) of the S1 subunit of the SARS-CoV-2 spike glycoprotein and their inhibitory potential against the ACE2-Spike has been studied. We believe that these compounds can be further tested as a potential therapeutic option against COVID-19.
ABSTRACT
The current 2019-nCoV outbreak is becoming extremely harmful and has affected the whole world. Its control is challenging because there is no effective vaccine or drug available for coronavirus disease. The Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), previously named as 2019 novel coronavirus (2019-nCoV), primarily targets the human respiratory system to lung lesions and lethal pneumonia. Natural products have always shown a crucial role in the process of drug development against various diseases. They may serve as leads for further drug development to combat emergent mutants of the coronavirus. In this review, the current status of natural compounds and their derivatives acting against different species of CoV are discussed.