Structural Landscape of SARS-CoV-2 entry & activation of spike glycoprotein & potential interventions.

The pandemic COVID19 illness caused by SARS-CoV-2, which produces pneumonia and lower respiratory tract infections, is a serious public health concern, with frightening mutations causing over 4.5 million deaths globally. Whilst effective immunisation shows promise globally, several antiviral treatments are being clinically evaluated to fill the "therapeutic gap" in treating infected people. Understanding the entire repertoire of diverse host factors engaged by SARS-CoV-2 for entry and pathogenicity is required for long-lasting potential therapeutics or vaccines. Here, using a structural and molecular approach, we show multistage processing of SARS-CoV-2 spike-protein for virion activation, infection, and how mutations influence it. We solved the structures of spike-protein in complex with different host cell factors (TMPRSS2, Furin, CD26 (DPP4), and NRP1) with functional activity, and these insights into uncovering how viral spike-protein engages and primed with these multiple host factors, in addition to ACE2, to hijack host cell entry. Furthermore, our COVID19 patient genome sequencing reveals that allele in TMPRSS2 (V160M) and Furin provided protection from COVID19 infection, and its structural mechanism is further addressed and potential drug clinical trials. Additionally, our large-scale retrospective cohort studies proved Arbidol and derivatives as potential therapies for COVID19, using structural studies, we demonstrated the mechanism of action of Arbidol in disrupting spike function. These findings cognize the complete mechanism of viral spike-glycoprotein processing/priming that leads to cascading entry into the host cell, paving the door for future vaccine development and identifying key targets. Our comprehensive, multifaceted research reveals the complexity of the SARS-CoV-2 spike-protein and clinical studies aid in therapies. References: 1. Li, F., et al., Nature Communications 12, 866 (2021). 2. Vankadari, N. & Jacqline, A., Emeging Microbes & Infections, 9(1), 601-604 (2020). 3. Vankadari, N. Int. Journal of Antimirobial Agents, 56(2),105998 (2020) 4. Andersen, K.G., et al., Nature Medicine 26, 450-452 (2020). 5. Qibin Liu et al., MedRxiv CSH Press (2021), March 22 (2) 6. Ravikanth, V et al., mGENE (2021), 5, e100930. NEJM (Reviewed) 7. Vankadari, N. ACS Journal of Physical Chemistry Letters, 11(16), 6655-663 (2020).