Rhabdovirus-Inducible MicroRNA-210 Modulates Antiviral Innate Immune Response via Targeting STING/MITA in Fish.

Viral infection induces type I IFN production, which plays critical roles in orchestrating the antiviral defense by inducing direct antiviral activities. To establish a persistent infection, viruses have evolved numerous strategies to specifically interfere with IFN production or its downstream mediators, thereby evading the immune responses. MicroRNAs (miRNAs) are a family of small noncoding RNAs that posttranscriptionally regulate the expressions of specific target genes. Although accumulating evidence demonstrates that miRNAs play vital roles in regulating viral infection, miRNAs that target intracellular sensors and adaptors of innate immunity have not been fully uncovered. In this paper, we identify fish miR-210 as a robust regulator involved in regulating virus-host interactions. We found that rhabdovirus significantly upregulated the expression of fish miR-210. Inducible miR-210 modulates virus-triggered type I IFN and inflammatory cytokine production by targeting stimulator of IFN genes (STING), thereby promoting viral replication. Furthermore, we demonstrated that miR-210 regulates innate immune response through NF-κB, IFN regulatory factor 3, and JAK/STAT signaling pathways. The collective findings indicate that inducible miR-210 plays a regulatory role in virus-host interactions through STING-mediated singling pathway by targeting STING.