丹参酚酸A通过激活Sirt3调控线粒体自噬防治酒精性肝病的作用机制研究

Alcohol liver disease (ALD) has been a leading risk factor for mortality worldwide. However, the safe and effective therapies for ALD in humans remain elusive, mainly due to the lack of our understanding on its detailed pathogenesis. Although Salvia, a kind of traditional Chinese medicine, has unique advantages in the prevention and treatment of ALD, its application in clinical treatment is limited as for its unclear mechanism. Our preliminary data show that exposure to salvianolic acid (SAA), a major derivative present in Salvia, can ameliorate oleic acid-induced lipid accumulation, while remains the mechanism unclear. Emerging evidence suggests that mitophagy suppression play pivotal roles in the onset and progression of ALD. Our previous results demonstrated that SAA can up-regulate the protein level of Sirt3 and Parkin. These data altogether support the following hypothesis: SAA mediated mitophagy induction through Sirt3/Pink/Parkin signaling pathway followed by inhibiting mitochondrial injury-induced cell death, and improved the abnormal lipids metabolism, ameliorated the lipid accumulation and the alcohol associated liver injury. In this proposal, we will employ multiple state-of-the-arts biomedical technologies and coupled the systematics and cellular signaling pathway to determine the significant role and the potential mechanism of mitophagy induction in ALD suppression regulated by SAA both in in vivo and in vitro model. Our ultimate goal is to provide new strategies for the clinical treatment and the development of novel therapeutic drugs based on SAA in treatment of ALD.

酒精性肝病(ALD)危害严重，且临床尚无有效治疗手段。活血化瘀中药丹参防治ALD具有独特优势，但作用机理不甚明确，限制了在临床治疗的应用。课题组前期研究发现，丹参主要单体丹参酚酸A(SAA)可以显著降低油酸诱导的肝细胞脂肪蓄积，然而机制尚不清楚。线粒体自噬是ALD发生发展的一个新机制。我们进一步研究表明，SAA可以通过活化去乙酰化酶Sirt3显著上调线粒体自噬标志蛋白Parkin（一种E3泛素连接酶）的表达。据此提出以下假说；SAA通过激活Sirt3介导的肝细胞线粒体自噬，抑制线粒体损伤引起的肝细胞死亡，改善肝脏脂质代谢，减少肝细胞脂肪累积，减轻酒精及代谢产物对肝脏的损伤是丹参治疗ALD的作用机制之一。拟从体内、体外两方面，利用RNA干扰等技术从系统学和细胞信号调控水平明确SAA激活线粒体自噬防治ALD的作用，并阐明其确切机制及靶点，为以SAA为主的治疗ALD的新型药物研发提供新思路。

ALD是由长期、大量饮酒导致的肝脏疾病，是全世界最普遍的肝病之一。酒精在体内代谢过程中引起的肝损伤和肝脏脂质蓄积能进一步进展成肝炎、肝硬化甚至是肝癌。流行病学结果发现，大部分 ALD 的患病人群集中在酒精性脂肪肝与酒精性肝炎的阶段。该阶段的主要病理表现肝细胞脂质蓄积与肝细胞损伤是可逆的。项目组研究发现SAA能有效改善酒精诱导的肝细胞损伤与肝脏脂质蓄积。为进一步探究SAA干预改善ALD的作用机制，项目组将SAA结合ALD发生发展的新机制——线粒体自噬，通过体内外实验相结合的方式，利用RNA干扰等技术手段探索防治ALD的新途径与新靶点，为新药的研发提供科学依据。.目前已按计划完成全部研究内容，共发表论文8篇，参与会议7次，博士研究生2人，硕士研究生3人。具体研究结果如下：.1. 明确了SAA对ALD的防治作用，SAA干预能够改善酒精诱导的肝损伤和肝脏脂质蓄积。.2. SAA干预能够激活ALD小鼠肝细胞自噬，而抑制肝细胞自噬显著加强了酒精诱导的肝细胞损伤和脂质蓄积。.3. SAA通过Sirt3/AMPK信号通路介导自噬改善酒精诱导的肝细胞损伤与肝脏脂质代谢异常。.上述研究结果表明，SAA能够有效改善酒精诱导的肝损伤与肝脏脂质代谢异常，针对自噬开发丹参类药物治疗ALD将有重要的现实意义。