SARS-CoV-2 encoded microRNAs are involved in the process of virus infection and host immune response

The outbreak of COVID-19 caused by SARS-CoV-2 is spreading worldwide, with the pathogenesis mostly unclear. Both virus and host-derived microRNA (miRNA) play essential roles in the pathology of virus infection. This study aims to uncover the mechanism for SARS-CoV-2 pathogenicity from the perspective of miRNA. We scanned the SARS-CoV-2 genome for putative miRNA genes and miRNA targets and conducted in vivo experiments to validate the virus-encoded miRNAs and their regulatory role on the putative targets. One of such virus-encoded miRNAs, MR147-3p, was overexpressed that resulted in significantly decreased transcript levels of all of the predicted targets in human, i.e., EXOC7, RAD9A, and TFE3 in the virus-infected cells. The analysis showed that the immune response and cytoskeleton organization are two of the most notable biological processes regulated by the infection-modulated miRNAs. Additionally, the genomic mutation of SARS-CoV-2 contributed to the changed miRNA repository and targets, suggesting a possible role of miRNAs in the attenuated phenotype of SARS-CoV-2 during its evolution. This study provided a comprehensive view of the miRNA-involved regulatory system during SARS-CoV-2 infection, indicating possible antiviral therapeutics against SARS-CoV-2 through intervening miRNA regulation.