Background: SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) is a highly transmissible and pathogenic coronavirus that first emerged in late 2019 and has since triggered a pandemic of acute respiratory disease named "coronavirus disease 2019" (COVID-19), poses a significant threat to all public health institutions in the absence of specific antiviral treatment.
Methods: The innate RNA interference (RNAi) pathway, on the other hand, allows for the development of nucleic acid-based antiviral drugs. It is a cellular gene-silencing event in which complementary small interfering RNA (siRNA) molecules cause sequence-specific degradation of target mRNA. Hence, in this current study, the potential of RNAi was utilized to construct siRNA molecules against specific target genes of SARS-CoV-2 structural proteins, such as the envelope protein gene (E), membrane protein gene (M), nucleocapsid phosphoprotein gene (N), and surface glycoprotein gene (S).
Results: Conserved sequence from 811 SARS-CoV-2 strains from around India was collected to construct 157 siRNAs that can inactivate E, M, N and S genes. The proposed siRNA molecules possessed sufficient nucleotide-based and other features for effective gene silencing and siRNAs' targets revealed no significant matches across the whole human genome and hence, siRNAs were found to have no off-target effects on the genome, ruling out the possibility of off-target silencing.
Conclusions: Finally, based on GC content, free energy of folding, free energy of binding, melting temperature and molecular docking analysis, 4 effective siRNA molecules were selected for each target gene which is proposed to exert the best action. Our engineered siRNA candidates could be used as a genome-level therapeutic treatment against various sequenced SARS-CoV-2 strains in India. However, future applications will necessitate additional validations in vitro and in vivo animal models.