An insight into the inhibitory mechanism of phytochemicals and FDA-approved drugs on the ACE2-Spike complex of SARS-CoV-2 using computational methods

Evaluating therapeutic potential of AYUSH-64 constituents against omicron variant of SARS-CoV-2 using ensemble docking and simulations

The COVID-19 pandemic in the later phase showed the presence of the B.1.1.529 variant of the SARS-CoV-2 designated as Omicron. AYUSH-64 a poly herbal drug developed by Central Council for Research in Ayurvedic Sciences (CCRAS) has been recommended by Ministry of Ayush in asymptomatic, mild to moderate COVID-19 patients. One of the earlier, in-silico study has shown the binding of the constituents of AYUSH-64 to the main protease (Mpro) of the SARS-CoV-2. This study enlisted four phytochemicals of AYUSH-64, which were found to have significant binding with the Mpro. In continuation to the same, the current study proposes to understand the binding of these four phytochemicals to main protease (Mpro) and receptor binding domain (RBD) of spike protein of the Omicron variant. An enhanced molecular docking methodology, namely, ensemble docking has been used to find the most efficiently binding phytochemical. Using molecular dynamics (MD) simulations and clustering approach it was observed that the Mpro and RBD Spike of Omicron variant of SARS-CoV-2 in complex with human ACE2 tends to attain 4 and 8 conformational respectively. Based on the docking studies, the best binding phytochemical of the AYUSH-64, akummicine N-oxide was selected for MD simulations. MD simulations of akummicine N-oxide bound to omicron variant of Mpro and RBD Spike-ACE complex was performed. The conformational, interaction and binding energy analysis suggested that the akummicine N-oxide binds well with Mpro and RBD Spike-ACE2 complex. The interaction between RBD Spike and ACE2 was observed to weaken in the presence of akummicine N-oxide. Hence, it can be inferred that, these phytochemicals from AYUSH-64 formulation may have the potential to act against the Omicron variant of SARS-CoV-2.

Identification and validation of shared gene signature of kidney renal clear cell carcinoma and COVID-19

Background

COVID-19 is a severe infectious disease caused by the SARS-CoV-2 virus, and previous studies have shown that patients with kidney renal clear cell carcinoma (KIRC) are more susceptible to SARS-CoV-2 infection than the general population. Nevertheless, their co-pathogenesis remains incompletely elucidated.

Methods

We obtained shared genes between these two diseases based on public datasets, constructed a prognostic risk model consisting of hub genes, and validated the accuracy of the model using internal and external validation sets. We further analyzed the immune landscape of the prognostic risk model, investigated the biological functions of the hub genes, and detected their expression in renal cell carcinoma cells using qPCR. Finally, we searched the candidate drugs associated with hub gene-related targets from DSigDB and CellMiner databases.

Results

We obtained 156 shared genes between KIRC and COVID-19 and constructed a prognostic risk model consisting of four hub genes. Both shared genes and hub genes were highly enriched in immune-related functions and pathways. Hub genes were significantly overexpressed in COVID-19 and KIRC. ROC curves, nomograms, etc., showed the reliability and robustness of the risk model, which was validated in both internal and external datasets. Moreover, patients in the high-risk group showed a higher proportion of immune cells, higher expression of immune checkpoint genes, and more active immune-related functions. Finally, we identified promising drugs for COVID-19 and KIRC, such as etoposide, fulvestrant, and topotecan.

Conclusion

This study identified and validated four shared genes for KIRC and COVID-19. These genes are associated with immune functions and may serve as potential prognostic biomarkers for KIRC. The shared pathways and genes may provide new insights for further mechanistic research and treatment of comorbidities.

Computational insights into binding mechanism of drugs as potential inhibitors against SARS-CoV-2 targets

Because of the scale of the novel coronavirus (COVID-19) pandemic and the swift transmission of this highly contagious respiratory virus, repurposing existing drugs has become an urgent treatment approach. The objective of our study is to unravel the binding mechanism of the Food and Drug Administration (FDA)-approved dexamethasone (Dex) and boceprevir (Boc) drugs with selected COVID-19 protein targets SARS-CoV-2 spike protein C-terminal domain (spike-CTD), main protease (M^pro), and interleukin-6 (IL-6). Another objective is to analyze the effects of binding Dex and Boc drugs on the interactions of viral spike protein to human angiotensin-converting enzyme 2 (hACE2). Molecular docking and one-microsecond-long molecular dynamics simulations of each of the six protein–drug complexes along with steered molecular dynamics (SMD) and umbrella sampling (US) methods have revealed the binding mode interactions and the physicochemical stability of the three targeted proteins with two drugs. Results have shown that both drugs bind strongly with the three protein targets through hydrogen bonding and hydrophobic interactions. A major finding from this study is how the binding of the drugs with viral spike protein affects its interactions at the binding interface with hACE2 protein. Simulations of drug-bound spike-CTD with hACE2 show that due to the presence of a drug at the binding interface of spike-CTD, hACE2 is being blocked from making putative interactions with viral protein at such interface. These important findings regarding the binding affinity and stability of the two FDA-approved drugs with the main targets of COVID-19 along with the effect of drugs on hACE2 interactions would contribute to COVID-19 drug discovery and development.