自噬在非酒精性脂肪性肝炎中的作用及机制研究

The pathogenesis of nonalcoholic fatty liver disease (NAFLD) is still not clear. Recent studies showed that autophagy play an important role in lipid deposition stage and liver fibrosis stage of NAFLD, but the role of macrophages in the non-alcoholic steatohepatitis (NASH) is still in blank. NASH is considered to be important in NAFLD development,and it has been a hot research focus in recent years.In our preliminary study, we had successfully constructed a rat NASH model by high fat diet, and used fatty acid induced steatosis in hepatocyte.We also detected LC3 expression in liver of NASH rats and found that LC3Ⅱ/Ⅰlevels in NASH rats much lower than control rats.This project intends to detect LC3 expression and to observe the formation of autophagosomes in NASH model and control group. Then autophagy blocker or agonists, autophagy gene Atg5 interfering RNA or Atg5 overexpression vectors were applied.In order to explore the upstream and downstream of autophagy regulation, we detect ATP, IL-6, MDA levels and proteins involved in AMPK/mTOR and Akt/mTOR pathways. This study, for the first time, investigate the role of autophages in NASH and its possible mechanism. This project provides a new idea for the exploration of NASH pathogenesis and therapeutic targets.

非酒精性脂肪性肝病（NAFLD）的发病机制尚不明确。最新研究发现自噬在NAFLD脂质沉积阶段甚至肝纤维化阶段发挥重要作用，但自噬在非酒精性脂肪性肝炎（NASH）中的作用仍是空白，而NASH可进展为肝硬化、肝癌，被认为是NAFLD发展中的重要阶段。前期研究成功构建NASH大鼠模型和脂肪变性肝细胞模型，并检测到肝组织中自噬体膜标识蛋白LC3表达的变化。本课题拟分别构建两种NASH动物和细胞模型，检测NASH模型中LC3表达，观察自噬体的形成；使用自噬阻断剂或激动剂，或以自噬表达基因Atg5干扰RNA或真核过表达载体转染细胞模型，检测ATP、IL-6、MDA水平和AMPK/mTOR和Akt/mTOR通路相关蛋白表达水平，探索自噬的上下游调控物。本研究首次研究自噬在NASH中的作用并探讨可能的作用机制，为阐明NASH的发病机制和探索治疗靶点提供新思路。

非酒精性脂肪性肝病（NAFLD）的发病机制尚不明确。最新研究发现自噬在NAFLD脂质沉积阶段甚至肝纤维化阶段发挥重要作用，但自噬在非酒精性脂肪性肝炎（NASH）中的作用仍是空白，而NASH 可进展为肝硬化、肝癌，被认为是NAFLD 发展中的重要阶段。本研究通过体内和体外实验观察了高脂和蛋氨酸胆碱缺乏诱导的NASH模型中自噬的发生情况，并通过自噬特异性调节物包括自噬阻断和自噬激活，探究自噬在非酒精性脂肪肝病中所起的作用。体内体外研究研发自噬阻断加剧NASH病变的进程，而自噬激活则能减轻NASH脂肪变性和炎症反映。体内外研究发现自噬激动剂白藜芦醇能显著抑制蛋氨酸胆碱缺乏诱导的NASH肝细胞的脂质蓄积、氧化应激和炎症反应用，其机制可能与激活自噬AMPK途径有关，而加入自噬抑制剂氯喹后，白藜芦醇对减轻NASH的作用减弱。本研究结果提示自噬通过AMPK通路在NASH中发挥重要作用，而自噬激动剂白藜芦醇干预能减轻NASH发展进程，为NASH的饮食/药物防治提供参考。