SHP调控肝星状细胞自噬在肝纤维化中的作用及机制

Inhibition of activated hepatic stellate cell (HSC) is the key to prevent and treat liver fibrosis. Recent studies proved that autophagy promote HSC activation and inhibition of HSC autophagy could probably alleviate the liver fibrosis. Our previous results revealed that targeted elevation of SHP in HSC could significantly suppress the HSC activation and liver fibrosis. We found that increase of SHP could reduce the formation of autophagy vehicle in HSC and significantly decrease the autophagy-related protein expression. Recent studies revealed that, FoxO3 is an important regulatory factor of autophagy, which is independent of the mTOR signaling pathway. Based on our previous results, we found that SHP might regulate FoxO3 activation, leading us to hypothesize that SHP could inhibit the HSC activation and liver fibrosis through the regulation of FoxO3-mediated-autophagy. To identify this assumption, we design to apply the activated HSC-targeted drug delivery system, developed by our lab, to increase the SHP expression in HSC of mice and establish the SHP over-expression and low-expression HSC cell lines. Then we will monitor the autophagic activity and HSC activation. Meanwhile, we will examine the autophagy-related protein expression by in vivo and in vitro experiments. Further, we will determine the activation of FoxO3 signaling pathway and measure the expression of its target genes to explore the potential mechanisms of SHP in regulation of autophagy. This study will have new insight into HSC activation and liver fibrosis, which will help to find the new strategy to treat the patients suffering from liver fibrosis.

抑制肝星状细胞（HSC）活化是防治肝纤维化的关键。近期研究证实自噬促进HSC活化，因此抑制HSC自噬有望减轻肝纤维化。我们前期研究发现靶向上调活化型HSC内小异二聚体伴侣（SHP）蛋白的表达可有效抑制HSC活化及肝纤维化，同时显著降低HSC自噬强度及自噬相关蛋白表达。FoxO3是mTOR信号通路以外重要的自噬调控因子。因此，我们推测SHP可能通过抑制FoxO3介导的自噬，从而减轻HSC活化及肝纤维化。本项目拟应用我们自主研发的靶向载药系统，选择性上调肝纤维化小鼠肝内活化型HSC中SHP表达，同时建立SHP稳定过表达及沉默的HSC细胞系，利用体内外实验观察HSC自噬及HSC活化水平的变化，明确SHP与HSC自噬的重要关系，并深入阐明SHP通过FoxO3相关信号通路调控HSC自噬的分子机制。本研究将揭示自噬介导的HSC活化及肝纤维化的分子机制，为肝纤维化的防治提供新靶标和新思路。

肝纤维化是各种慢性肝病发生发展的共同病理基础和特征。肝星状细胞（HSC）的活化是肝纤维化的中心事件，抑制其活化是防治肝纤维化的关键环节。近期研究证实HSC自噬促进HSC活化，因此抑制HSC自噬有望减轻肝纤维化。本课题从体内和体外实验两方面分析和探讨了小异二聚体伴侣（SHP）对HSC的调控作用，发现靶向上调活化型HSC内SHP表达可有效抑制HSC活化及肝纤维化，同时显著降低HSC自噬强度及自噬相关蛋白表达。我们成功制备靶向于活化型HSC的基因载药系统RGD-PEG-PEI/SHP，通过体外研究证实RGD-PEG-PEI/SHP的HSC靶向性，并利用小鼠模型证实靶向HSC的SHP载药系统具有显著的抗肝纤维化作用。我们利用LX2细胞系构建SHP梯度表达体系以及过表达/低表达体系，发现SHP的表达水平与HSC活化水平及其自噬程度呈显著负相关，提示SHP可能通过下调HSC自噬水平抑制HSC活化，从而缓解肝脏纤维化。总之，我们的研究有助于阐述SHP与HSC活化的相互关系及其参与调控肝纤维化的相关机制，为靶向治疗肝纤维化打下理论基础。本项研究按计划按时完成了预期目标，目前已发表SCI论著5篇，中文核心期刊论著2篇，在国际权威会议大会壁报交流3次，培养硕士研究生1名。