Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, PR China.
Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, PR China.
Fish Shellfish Immunol. 2020 Mar;98:908-916. doi: 10.1016/j.fsi.2019.11.053. Epub 2019 Nov 23.
Autophagy is an evolutionarily conserved cellular degradation process that is essential for homeostasis. As a cell steward, autophagy is thought to be a process that may have evolved to combat intracellular pathogens. However, some virus can subvert or utilize autophagy-related membrane structures to increase viral replication. The red-spotted grouper nervous necrosis virus (RGNNV) is a fish pathogen which leads to disastrous viral nervous necrosis in larvae and juvenile groupers and other marine fishes. To better comprehend the pathogenesis and replication mechanism of RGNNV, we investigated the relationship between RGNNV and autophagy. Here, we demonstrated that RGNNV induced autophagy in grouper spleen (GS) cells, as the significant increase in ultrastructural autophagosome-like vesicles, fluorescent punctate pattern of microtubule-associated protein 1 light chain 3 (LC3), and the conversion of LC3-I to LC3-II. Additionally, ultraviolet-inactivated RGNNV and the capsid protein also triggered autophagy. Enhancement of autophagy contributed to RGNNV replication, whereas blocked autophagy decreased RGNNV replication. Moreover, impeded fusion of autophagosomes and lysosomes also reduced RGNNV replication, indicating that RGNNV utilized the different steps of autophagy pathway to facilitate viral replication. The further study showed that RGNNV induced autophagy through activating the phosphorylation of eIF2α and inhibiting the phosphorylation of mTOR. These results will assist the search for novel drugs targets and vaccine design against RGNNV from the perspective of downregulating autophagy.
自噬是一种进化上保守的细胞降解过程，对维持细胞内环境稳定至关重要。作为细胞管家，自噬被认为是一种可能进化而来的过程，可以对抗细胞内病原体。然而，一些病毒可以颠覆或利用与自噬相关的膜结构来增加病毒复制。红鳍东方鲀神经坏死病毒（RGNNV）是一种鱼类病原体，可导致幼鱼和幼鱼阶段的东方鲀和其他海洋鱼类发生灾难性的病毒性神经坏死病。为了更好地理解 RGNNV 的发病机制和复制机制，我们研究了 RGNNV 与自噬之间的关系。在这里，我们证明 RGNNV 诱导了东方鲀脾脏（GS）细胞中的自噬，表现为超微结构自噬体样囊泡的显著增加、微管相关蛋白 1 轻链 3（LC3）的荧光点状模式以及 LC3-I 向 LC3-II 的转化。此外，紫外灭活的 RGNNV 和衣壳蛋白也触发了自噬。增强自噬有助于 RGNNV 的复制，而阻断自噬则减少了 RGNNV 的复制。此外，抑制自噬体与溶酶体的融合也减少了 RGNNV 的复制，表明 RGNNV 利用自噬途径的不同步骤来促进病毒复制。进一步的研究表明，RGNNV 通过激活 eIF2α 的磷酸化和抑制 mTOR 的磷酸化来诱导自噬。这些结果将有助于从下调自噬的角度寻找针对 RGNNV 的新型药物靶点和疫苗设计。
