Hepatitis C Virus Non-Structural Protein 5A (NS5A) Disrupts Mitochondrial Dynamics and Induces Mitophagy
Hepatitis C Virus Non-Structural Protein 5A (NS5A) Disrupts Mitochondrial Dynamics and Induces Mitophagy
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DOI：
10.3390/cells8040290
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发表时间：
2019-04-01
期刊：
影响因子：
6
通讯作者：
Lin, Liang-Tzung
中科院分区：
文献类型：
--
作者：
Jassey, Alagie;Liu, Ching-Hsuan;Lin, Liang-Tzung
线粒体自噬是自噬的一种选择性形式，针对受损的线粒体进行溶酶体降解。尽管 HCV 感染已被证明可诱导线粒体自噬，但其确切的潜在机制和效应蛋白仍不清楚。在此，我们证明了 HCV 非结构蛋白 5A (NS5A) 在调节细胞线粒体自噬中发挥着关键作用。具体来说，肝癌细胞中 HCV NS5A 的表达引发了线粒体自噬的特征，包括线粒体断裂、线粒体膜电位丧失和 Parkin 易位至线粒体。此外，通过 NS5A 的表达诱导线粒体自噬导致自噬通量增加，如巴弗洛霉素存在下 LC3II 的积累和 p62 蛋白水平随时间依赖性下降所证明的那样。有趣的是，NS5A 的表达同时增强了活性氧 (ROS) 的产生，并且用抗氧化剂处理减弱了 NS5A 诱导的线粒体自噬事件。这些现象在表达 NS5A 的 HCV 亚基因组复制子细胞中也有类似的重现。最后，我们证明，HCV 核心的表达（已被证明可以抑制线粒体自噬）可以阻断含有 HCV 复制亚基因组或单独表达 NS5A 的细胞中的线粒体自噬诱导。因此，我们的结果确定了 NS5A 作为 HCV 诱导的线粒体自噬的重要调节剂的新作用，并且对于拓宽我们对 HCV-线粒体自噬相互作用的理解具有重要意义。
Mitophagy is a selective form of autophagy, targeting damaged mitochondria for lysosomal degradation. Although HCV infection has been shown to induce mitophagy, the precise underlying mechanism and the effector protein responsible remain unclear. Herein, we demonstrated that the HCV non-structural protein 5A (NS5A) plays a key role in regulating cellular mitophagy. Specifically, the expression of HCV NS5A in the hepatoma cells triggered hallmarks of mitophagy including mitochondrial fragmentation, loss of mitochondrial membrane potential, and Parkin translocation to the mitochondria. Furthermore, mitophagy induction through the expression of NS5A led to an increase in autophagic flux as demonstrated by an accumulation of LC3II in the presence of bafilomycin and a time-dependent decrease in p62 protein level. Intriguingly, the expression of NS5A concomitantly enhanced reactive oxygen species (ROS) production, and treatment with an antioxidant attenuated the NS5A-induced mitophagy event. These phenomena are similarly recapitulated in the NS5A-expressing HCV subgenomic replicon cells. Finally, we demonstrated that expression of HCV core, which has been documented to inhibit mitophagy, blocked the mitophagy induction both in cells harboring HCV replicating subgenomes or expressing NS5A alone. Our results, therefore, identified a new role for NS5A as an important regulator of HCV-induced mitophagy and have implications to broadening our understanding of the HCV-mitophagy interplay.