SARS-CoV-2 Variants Impact on Key Signaling Pathways Metamorphoses into Severity

The Severe Acute Respiratory Syndrome Coronavirus-2 causes a dreadful Coronavirus Disease namely COVID-19. Respiratory system is the primary target of the virus. It also impairs other major organs such as kidney, heart, liver, brain etc. Multiple novel variants of SARS-CoV-2 have appeared since the SARS-CoV-2 pandemic occurred which are linked to increased virulence, disease transmission and severity. The virus attacks the host signalling pathways to maintain a favourable environment for its spread. The present study focuses on the comprehensive analysis of major signaling pathways affected due to several variants of SARS-CoV-2 leading to abnormalities in cell growth and differentiation. The information was curated from the weblinks of several platforms like WHO, CDC, PANGO, Nextstrain clade and GISAID clade. The data on signaling pathways and comorbidities was generated by screening of different research and review articles. SARS-CoV-2 consolidates the cytoskeleton of the host for effective cell invasion and modulates the transcription processes to enable the translation of viral protein(s). These events lead to significant increase and prolonged hyper inflammation. Further, a decreased interferon (IFN) response along with increased interleukin production leading to cytokine storm is observed. Deregulation of interleukin pathways, TNF-alpha signalling through JAK/STAT-3 signalling, MAPK1, mTOR, PI3K are few other signalling pathways that are affected on SARS-CoV-2 infection. This review represents a comprehensive analysis of the vigorous life cycle of SARS CoV-2, its different variants affecting host signalling pathways which eventually cause dysfunctioning of several organs and development of comorbidities.