SIRT1/AMPK信号通路介导肝细胞-肝星状细胞交叉对话调控酒精性肝病的作用机制研究

Alcoholic liver disease (ALD) is a result of long-term heavy drinking. ALD is mainly characterized by liver injury, excessive accumulation of lipid and activation of hepatic stellate cells (HSCs). SIRT1 and AMPK are the key regulators of energy metabolism, which activated feedback circuit to maintain the homeostasis of energy metabolism to provide a new target for the treatment of ALD. We found that SIRT1 agonist and AMPK agonist reduced the accumulation of lipid in chronic alcohol-feeding mice and also inhibited the activation of HSCs primed by ethanol. Therefore, we assume that activating the feedback circuit of SIRT1/AMPK will block the crosstalk between hepatocytes and HSCs, eventually improve lipid metabolism and reverse fibrotic changes in alcoholic liver fibrosis. Herein, by applying gene knock-down or over-expression cell lines and cell co-culture system, we elucidate cell type-specific role of SIRT1/AMPK signaling pathway to modulate hepatocytes accumulation of lipid and HSCs activation; and then applying in vivo model of Lieber-DeCarli ethanol-containing diets induced ALD and gene knockout mice to investigate the underlying mechanisms of alcoholic fatty liver and alcoholic liver fibrosis modulated by SIRT1/AMPK signaling pathway. Thus, this work will add the new knowledge for prevention and treatment of ALD.

酒精性肝病（ALD）是由长期过量饮酒导致的肝脏疾病。肝脏损伤-肝细胞脂肪蓄积-肝星状细胞激活是ALD发生发展的核心环节。SIRT1及AMPK是能量代谢的关键调节因子，可相互激活形成反馈回路从而维持机体能量代谢稳态，为ALD的治疗提供新的干预靶点。我们发现SIRT1及AMPK激动剂可减轻肝脏脂肪蓄积，并能抑制酒精刺激的肝星状细胞活化。由此提出激活SIRT1/AMPK信号通路及其反馈回路，阻断肝细胞与肝星状细胞交叉对话，将改善肝脏脂质代谢并逆转酒精性肝纤维化。本项目拟利用基因过表达和RNA干扰技术及细胞共培养体外模型，明确SIRT1/AMPK信号通路调控肝细胞脂肪蓄积-肝星状细胞激活的多靶向调控网络的关键位点；采用Lieber-DeCarli酒精液体饲料诱导ALD小鼠模型和基因敲除小鼠，阐明SIRT1/AMPK信号通路调控酒精性脂肪肝-酒精性肝纤维化进程的作用机制，为ALD的防治提供新的思路。

酒精性肝病是我国常见的肝脏疾病之一，疾病谱包括酒精性脂肪肝、酒精性肝炎、酒精性肝纤维化、酒精性肝硬化及肝癌。酒精性肝纤维化是酒精性肝病向酒精性肝硬化发展的必经阶段，其主要特征是脂肪变性、肝细胞损伤、肝脏炎症、肝星状细胞活化，在治疗上缺乏有效的治疗方案，因此探究影响酒精性肝病进展的致病机制可为将来的治疗提供潜在的干预靶点。本项目通过细胞模型及动物模型，对酒精性肝病的发病机制进行初步研究。我们利用慢性酒精喂养加急性酒精灌胃建立酒精性肝病小鼠模型，SRT1720（SIRT1激动剂）、AICAR（AMPK激动剂）显著减少小鼠肝脏组织中脂肪沉积，炎性细胞浸润以及胶原组织生成，从体内角度深入研究SIRT1/AMPK信号通路介导的肝细胞脂肪蓄积-肝星状细胞激活的分子机制。体外模型中采用肝细胞、肝星状细胞单独培养及共培养，模拟体内实际作用机制，SRT1720及AICAR处理后可以有效增加肝细胞、肝星状细胞共培养中酒精诱导的SIRT1表达及AMPK磷酸化水平，进一步阐明SIRT1/AMPK信号通路是肝细胞-肝星状细胞交叉对话调控酒精性脂肪肝-酒精性肝纤维化的共同关键信号网络。本研究以SIRT1/AMPK作为切入点，明确了其在肝细胞与肝星状细胞交叉对话中的反馈调节及其作用关键位点，阐明SIRT1/AMPK信号通路调节酒精性脂肪肝-酒精性肝纤维化进程的作用机制，为相关酒精性肝病的防治及在药物应用上提供充分的理论基础。