Hsiao Yuan-Chao, Chang Chih-Wei, Yeh Chau-Ting, Ke Po-Yuan
Department of Biochemistry & Molecular Biology, Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan.
Liver Research Center, Chang Gung Memorial Hospital, Taoyuan 33305, Taiwan.
Pathogens. 2024 Dec 23;13(12):1139. doi: 10.3390/pathogens13121139.
Chronic HCV infection is a risk factor for end-stage liver disease, leading to a major burden on public health. Mitophagy is a specific form of selective autophagy that eliminates mitochondria to maintain mitochondrial integrity. HCV NS5A is a multifunctional protein that regulates the HCV life cycle and may induce host mitophagy. However, the molecular mechanism by which HCV NS5A activates mitophagy remains largely unknown. Here, for the first time, we delineate the dynamic process of HCV NS5A-activated PINK1/Parkin-dependent mitophagy. By performing live-cell imaging and CLEM analyses of HCV NS5A-expressing cells, we demonstrate the degradation of mitochondria within autophagic vacuoles, a process that is dependent on Parkin and ubiquitin translocation onto mitochondria and PINK1 stabilization. In addition, the cargo receptors of mitophagy, NDP52 and OPTN, are recruited to the mitochondria and required for HCV NS5A-induced mitophagy. Moreover, ATG5 and DFCP1, which function in autophagosome closure and phagophore formation, are translocated near mitochondria for HCV NS5A-induced mitophagy. Furthermore, autophagy-initiating proteins, including ATG14 and ULK1, are recruited near the mitochondria for HCV NS5A-triggered mitophagy. Together, these findings demonstrate that HCV NS5A may induce PINK1/Parkin-dependent mitophagy through the recognition of mitochondria by cargo receptors and the nascent formation of phagophores close to mitochondria.
慢性丙型肝炎病毒（HCV）感染是终末期肝病的一个危险因素，给公共卫生带来了重大负担。线粒体自噬是一种选择性自噬的特殊形式，可清除线粒体以维持线粒体的完整性。HCV NS5A是一种多功能蛋白，可调节HCV生命周期并可能诱导宿主线粒体自噬。然而，HCV NS5A激活线粒体自噬的分子机制在很大程度上仍不清楚。在此，我们首次描绘了HCV NS5A激活的依赖PINK1/Parkin的线粒体自噬的动态过程。通过对表达HCV NS5A的细胞进行活细胞成像和相关光电子显微镜分析，我们证明了自噬泡内线粒体的降解，这一过程依赖于Parkin以及泛素向线粒体的转运和PINK1的稳定。此外，线粒体自噬的货物受体NDP52和OPTN被招募到线粒体上，并且是HCV NS5A诱导的线粒体自噬所必需的。而且，在自噬体封闭和吞噬泡形成中起作用的ATG5和DFCP1会转移到线粒体附近，以参与HCV NS5A诱导的线粒体自噬。此外，包括ATG14和ULK1在内的自噬起始蛋白会被招募到线粒体附近，以参与HCV NS5A触发的线粒体自噬。总之，这些发现表明，HCV NS5A可能通过货物受体对线粒体的识别以及靠近线粒体的吞噬泡的新生形成来诱导依赖PINK1/Parkin的线粒体自噬。
