State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, China.
PLoS One. 2013;8(1):e52909. doi: 10.1371/journal.pone.0052909. Epub 2013 Jan 8.
In addition to manipulating cellular homeostasis and survivability, autophagy also plays a crucial role in numerous viral infections. In this study, we discover that Japanese encephalitis virus (JEV) infection results in the accumulation of microtubule-associated protein 1 light chain 3-II (LC3-II) protein and GFP-LC3 puncta in vitro and an increase in autophagosomes/autolysosomes in vivo. The fusion between autophagosomes and lysosomes is essential for virus replication. Knockdown of autophagy-related genes reduced JEV replication in vitro, as indicated by viral RNA and protein levels. We also note that JEV infection in autophagy-impaired cells displayed active caspases cleavage and cell death. Moreover, we find that JEV induces higher type I interferon (IFN) activation in cells deficient in autophagy-related genes as the cells exhibited increased phosphorylation and dimerization of interferon regulatory factor 3 (IRF3) and mitochondrial antiviral signaling protein (MAVS) aggregation. Finally, we find that autophagy is indispensable for efficient JEV replication even in an IFN-defective background. Overall, our studies provide the first description of the mechanism of the autophagic innate immune signaling pathway during JEV infection.
除了操纵细胞内稳态和存活能力外，自噬在许多病毒感染中也起着至关重要的作用。在这项研究中，我们发现日本脑炎病毒（JEV）感染导致体外微管相关蛋白 1 轻链 3-II（LC3-II）蛋白和 GFP-LC3 斑点的积累，以及体内自噬体/溶酶体的增加。自噬体与溶酶体之间的融合对于病毒复制是必不可少的。自噬相关基因的敲低减少了体外 JEV 的复制，这可以从病毒 RNA 和蛋白水平上看出。我们还注意到，在自噬受损的细胞中，JEV 感染显示出活性半胱天冬酶的切割和细胞死亡。此外，我们发现 JEV 在自噬相关基因缺陷的细胞中诱导更高水平的 I 型干扰素（IFN）激活，因为细胞中干扰素调节因子 3（IRF3）和线粒体抗病毒信号蛋白（MAVS）的磷酸化和二聚化以及聚集增加。最后，我们发现即使在 IFN 缺陷的背景下，自噬对于 JEV 的有效复制也是不可或缺的。总的来说，我们的研究首次描述了 JEV 感染期间自噬先天免疫信号通路的机制。
