RNAi-based antiviral immunity.

RNA interference (RNAi) is a gene silencing mechanism mediated by small RNAs derived from double-stranded RNA (dsRNA), capable of silencing specific genes. Following viral invasion, the dsRNA produced during viral replication is cleaved by the host cell's Dicer protein, generating virus-derived small interfering RNAs (virus-derived small interference RNAs, vsiRNA). These vsiRNAs then guide the cleavage and degradation of viral RNA via the RNAi pathway, exerting an antiviral effect. Therefore, RNAi is also recognized as an efficient antiviral immune pathway during viral infection. However, through long-term evolution, viruses have developed various strategies to counteract RNAi. For instance, they encode specific viral suppressors of RNAi (VSRs) that target and antagonize key molecules in this pathway. Research indicates that designing drugs to specifically target VSRs can "unlock" the antiviral function of RNAi within host cells, demonstrating highly potent and relatively broad-spectrum antiviral activity. Furthermore, viral infection can also be regulated by host- or virus-derived microRNAs (miRNAs). The role of miRNAs in viral infection provides new targets for antiviral therapy. In this review, we summarize the mechanism of RNAi in antiviral immunity, recent research advances, and its application prospects in antiviral therapy, aiming to provide theoretical support for antiviral immunity research and treatment.