Nuclear RNAi Modulates Influenza A Virus Infectivity By Downregulating Type-I Interferon Response. Nuclear RNAi Modulates Influenza A Virus Infectivity By Downregulating Type-I Interferon Response

The role of Argonaute (AGO) proteins and the RNA interference (RNAi) machinery in mammalian antiviral response has been debated. Therefore, we set out to investigate how mammalian RNAi impacts influenza A virus (IAV) infection. We demonstrate that IAV infection triggers nuclear accumulation of AGO2, which is directly facilitated by p53 activation. Mechanistically, we show that IAV induces nuclear AGO2 targeting of TRIM71, a proposed AGO2 E3 ligase, and type-I interferon-pathway genes for silencing. Hence, the RNAi machinery is highjacked by the virus to evade the immune system and support viral replication. We demonstrate that the FDA approved drug arsenic trioxide prevents nuclear AGO2:p53 accumulation, thereby increasing interferon response and decreasing viral replication in vitro and in a mouse model in vivo. Our data indicates that targeting the AGO2:p53-mediated silencing of innate immunity may offer a promising strategy to mitigate viral infections. Overall design: We performed miRNAseq after AGO1-4 IP in cells treated wih PR8 virus in HEK293 cells that were fractionatd into cytoplasmic andn nuclear fraction

关于Argonaute（AGO）蛋白与RNA干扰（RNAi）分子机器在哺乳动物抗病毒应答中的作用，学界长期存在争议。为此，我们旨在探究哺乳动物RNAi系统对甲型流感病毒（IAV）感染过程的影响。本研究证实，IAV感染可诱导AGO2发生核积累，且该过程直接由p53活化所介导。机制层面研究显示，IAV可诱导核内AGO2靶向TRIM71（一种已被报道的AGO2 E3泛素连接酶）以及I型干扰素通路相关基因以实现转录沉默。由此可见，病毒会劫持RNA干扰系统以逃避免疫监视并促进自身复制。我们证实，美国食品药品监督管理局（FDA）获批药物三氧化二砷可阻断AGO2:p53复合物的核积累，进而在体外实验与小鼠体内模型中增强干扰素应答并抑制病毒复制。本研究数据表明，靶向AGO2:p53介导的先天免疫沉默通路，或可为病毒感染的防治提供极具潜力的新策略。实验整体设计：我们将经PR8病毒处理的HEK293细胞分级分离为细胞质与细胞核组分，随后对AGO1-4进行免疫沉淀（IP）并开展microRNA测序（miRNAseq）。