HCV活化内源性大麻素系统诱导不完全线粒体自噬在慢性肝病进展中的作用

Hepatitis C virus (HCV) infection easily causes chronic hepatitis, liver fibrosis, cirrhosis and even hepatocellular carcinoma, which seriously does harm to human health. Endocannabinoids system and mitochondrial autophagy (mitophagy) play important roles in the development of fatty liver, fibrosis and cirrhosis by HCV infection. But the molecular mechanism behind this phenomenon is still unclear. Our former work confirmed that endocannabinoids system activation by HCV infection led to mitochondrial function disorders of hepatocytes and imbalance of induction and degradation of autophagy. We suppose that HCV infection activates endocannabinoids system to suppress mitochondrial function, not only induces incomplete mitophagy of hepatocytes, hepatic stellate cell and Kupffer cell by PI3K/Akt/mTOR signaling pathway to cause hepatocytes apoptosis, inflammatory response and liver fibrosis, but also induces incomplete lipophagy of hepatocytes to cause lipid metabolism disorder and promote HCV replication. Utilizing the co-culture of replicon cell with Kupffer cells and stellate cells, and harboring HCV adenovirus vectors mice, we study the role of apoptosis, steatosis, inflammatory and fibrosis by HCV activation endocannabinoids system to induce incomplete mitophagy and lipophagy of hepatocytes, incomplete mitophagy of hepatic stellate cell and Kupffer cell, which lays a foundation for retrieving endocannabinoids system activity (blockade CB1R or activation CB2R) as new target of anti-HCV therapy.

HCV感染易引起慢性肝炎、肝纤维化、肝硬化甚至肝癌，严重危害公众健康。内源性大麻素系统（ECS）和线粒体自噬在HCV所致的脂肪肝、肝纤维化、肝硬化的发生中起重要作用，但具体机制不清。我们前期研究表明HCV活化ECS导致肝细胞线粒体功能紊乱，引起自噬诱导和降解失衡。我们推测HCV活化ECS通过PI3K/Akt/mTOR信号通路诱导肝细胞、肝星状细胞、Kuffer细胞发生不完全线粒体自噬，导致肝细胞凋亡，增加炎症反应，促进肝纤维化；不完全脂滴自噬导致肝细胞脂代谢紊乱促进自身复制。拟利用HCV复制子细胞与肝星状细胞、Kupffer细胞共培养及携带HCV腺病毒载体的鼠模型，阐明HCV活化ECS诱导肝细胞、肝星状细胞、Kuffer细胞发生不完全线粒体自噬、不完全脂滴自噬在肝细胞凋亡、脂肪变、炎症、纤维化中的作用，为阻断CB1R或激活CB2R成为抗HCV治疗的新靶标奠定理论基础。

HCV感染易引起慢性肝炎、肝纤维化、肝硬化甚至肝癌，严重危害公众健康。内源性大麻素系统（ECS）和线粒体自噬在HCV所致的脂肪肝、肝纤维化、肝硬化的发生中起重要作用。我们利用表达HCV核心蛋白的HepG2细胞与肝星状细胞共培养，证实HCV核心蛋白增加肝星状细胞2-AG水平，上调肝细胞CB1R表达；增加线粒体ROS水平和Ca2+浓度，降低线粒体膜电位；下调Akt和mTOR活性，自噬相关蛋白LC3-II水平增加，而p62蛋白表达水平无变化，引起不完全线粒体自噬。利用HCV小鼠进一步发现HCV核心蛋白活化内源性大麻素系统，下调脂联素及受体表达，自噬相关蛋白LC3-II水平增加，而p62蛋白表达水平无变化，引起不完全脂滴自噬，导致肝脂肪变性。利用表达HCV核心蛋白的HepG2细胞与肝窦内皮细胞、肝星状细胞共培养，发现HCV感染(尤其是HCV核心蛋白) 下调SIRT1信号活化内源性大麻素系统，通过SIRT1-脂联素信号通路改变肝窦内皮细胞功能导致肝窦微循环障碍；通过脂联素受体-AMPK-SIRT1信号通路活化肝星状细胞导致肝纤维化。这些结果为改变内源性大麻素系统活性成为抗HCV治疗的新靶标奠定理论基础。