Cellular miR-24-3p inhibits vaccinia virus replication by targeting kinesin-like protein KIF21B

Microribonucleic acids (miRNAs) play diverse roles in numerous biological processes. miRNA-24-3p (miR-24-3p) has been reported to play an important role in viral infection. However, little is known about the involvement of miR-24-3p in persistent vaccinia virus infection. In this study, we discovered that vaccinia virus Western Reserve (VACV-WR) infection suppressed miR-24-3p expression. Delivery of synthetic miR-24-3p mimics into cells reduced viral genome replication, protein levels, and viral titers in VACV-WR-infected cells. Target prediction analysis identified KIF21B as a host target of miR-24-3p, and KIF21B deficiency significantly decreased VACV-WR replication and infection, suggesting that KIF21B is an important host factor facilitating VACV replication. Finally, in a VACV-infected mouse model, miR-24-3p was delivered using lipid nanoparticles (LNP), resulting in attenuated weight loss, higher survival rates, and lower viral loads, confirming that miR-24-3p overexpression significantly restricts VACV replication. In summary, our study demonstrates that miR-24-3p targets the host KIF21B sequence to coordinate suppression of VACV replication, providing a potential therapeutic strategy for VACV treatment.