The Activation of Antiviral RNA Interference Not Only Exist in Neural Progenitor Cells But Also in Somatic Cells in Mammals

The RNA interference (RNAi) pathway directs an important antiviral immunity mechanism in plants and invertebrates. Recently, we and others have demonstrated that the induction and suppression of antiviral RNAi response are also conserved in mammals, at least to five distinct RNA viruses, including Zika virus (ZIKV). ZIKV preferentially infects neuronal progenitor cells (NPCs) in the developing fetal brain. Xu et al. have revealed that ex vivo ZIKV infection induces RNAi-mediated antiviral response in human NPCs, but not in the more differentiated NPCs or somatic cells. However, less is known about the in vivo property or function of the virus-derived small-interfering RNAs (vsiRNAs) targeting Zika virus. Here we report a surprising observation: viral small RNAs (vsRNAs) targeting ZIKV were produced in vivo upon infection in both central neuron system (CNS) and muscle tissues. In addition, our findings demonstrate the production of canonical vsiRNAs in murine CNS upon antiviral RNAi activation by Sindbis virus, suggesting the possibility of antiviral immune strategy applied by mammals in the CNS.