Curcumin调控活化型HSC衰老在抗肝纤维化中的作用及分子机理研究

Activation of HSC is the central event in hepatic fibrosis. Previous studies mainly focus on inhibition of HSC activation and induction of HSC apoptosis. Senescence of activated HSC and the related molecular mechanisms are rarely investigated. Our previous studies showed that curcumin could potently inhibit HSC activation to exert its antifibrotic effects by targeting PPARγ. We herein creationally put forward that curcumin has effects on senescence of activated HSC associated with PPARγ regulation of p53 signaling pathways. Curcumin also affects the interactions between NK cells and senescent HSC. To test these hypotheses, we first use rat liver fibrosis model induced by CCl4 and BDL to investigate the correlation between the antifibrotic effects and senescence of activated HSC. Then we use HSC culture system and p53-/- mice to further study the curcumin effects on cell cycle, telomerase system, p53 and PPARγ signal transductions. Based on the establishment of the critical role of p53 in curcumin intervention of senescence of activated HSC, we attempt to elucidate the molecular mechanisms of drug action, which may be associated with PPARγ/p53 regulation system. Finally, we investigate whether curcumin can affect the clearance of activated HSC by NK cells. Through these studies, we can interpret the actions of curcumin on HSC senescence and elucidate the underlying molecular mechanisms. These studies provide basis for developing curcumin as promising antifibrotic agent for clinical application.

肝星状细胞（HSC）活化是肝纤维化（HF）发生的核心环节。既往国内外抗HF研究多聚焦于抑制HSC活化和增殖及促进其凋亡，忽略了活化型HSC衰老及相关机制在其中扮演的重要角色。我们前期工作表明，姜黄素（Cur）可有效抑制HSC活化发挥抗HF作用并明确PPARγ为其作用靶标。本项目创新性地提出调控活化型HSC衰老可能是Cur抗HF的新机制。为此，本研究拟利用CCl4与胆管结扎HF模型，首先明确Cur对HF的抑制作用与活化型HSC衰老之间相关；然后利用活化型HSC衰老体外模型和p53-/-小鼠，研究Cur对HSC细胞周期、端粒酶系统、p53和PPARγ分子的影响，阐明Cur激活PPARγ调控p53基因从而影响活化型HSC衰老的机制；最后研究Cur对NK细胞清除衰老HSC的影响；以此从新的视角阐明Cur抗HF的作用机制，预期研究成果可望为药物防治HF提供新策略和新靶点。

本项目阐明了姜黄素（Curcumin）通过激活PPARγ/P53诱导活化型肝星状细胞（HSC）衰老的作用及分子机制研究。实验结果发现Curcumin促进了活化型HSC衰老，主要体现在诱导衰老标志物半乳糖苷酶SA-β-gal、衰老相关因子P16、P21和Hmga1的表达，阻滞细胞周期于G1期及损伤了端粒酶系统。进一步深入研究发现PPARγ在Curcumin调控活化型HSC中扮演重要角色。Curcumin促进了PPARγ入核并激活下游P53，P53的大量表达阻滞了细胞周期进程，诱导了活化型HSC衰老。衰老的HSC表面大量表达自然杀伤细胞（NK细胞）受体相关配基MICA、ULBP2，促进NK细胞向衰老型HSC聚集，通过胞吐作用杀伤靶细胞，从而起到逆转肝纤维化的作用。同时，本课题组鉴于川芎嗪在祖国医学中与姜黄素同为常用的活血化瘀药物，且具有抗实验性肝纤维化作用，但对其作用机制知之甚少的基础上，研究了川芎嗪影响活化型HSC衰老的作用及其机制，作为本研究项目的拓展与补充。项目研究期间共发表相关论文52篇，其中SCI论文34篇；共培养硕士和博士研究生18人，其中已毕业硕士8人，博士1人；在中药活性成分及其衍生物抗肝纤维化与肿瘤方面取得发明专利一项；带领大学生参加挑战杯比赛并多次获奖。