Yap与Hedgehog 信号在激活HSC诱发肝纤维化中的相互作用机制探索

Liver fibrosis is the primary and must be stage of chronic liver disease. Early detection and treatment of liver fibrosis is significant for liver disease prevention. The central mechanism of liver fibrosis is the transformation of Hepatic stellate cells (HSC) to myofibroblasts (MF). At present, mechanism of HSC early activation is still need to be explored. Recently, it was found that Yap can drive early HSC activation. Hedgehog (Hh) signal is also involved in HSC activation and liver fibrosis regulation. It was reported that the two factors have interactions in some disease. Thus, we infer that Yap and Hh may have interations with each other during activating HSC and inducing liver fibrosis. Previously we have found that Yap overexpression is related with zebrafish liver fibrosis. In this project, iCRISPR-Cas9 will be used to establish liver-specific Yap knockout transgenic zebrafish. Combining with HSC labeled transgenic line and fibrosis stress, we will systematically verify that Yap can initiate HSC activation and induce liver fibrosis, and explore the interactions between Yap and Hh signal. The conclusion will be as a supplementary for HSC activation mechanism and will provide experimental support for early diagnosis of liver fibrosis and anti-fibrosis drug research.

肝纤维化是慢性肝病发展的必经阶段，及早发现与治疗对肝重病防治具有重要意义。肝星状细胞（Hepatic stellate cells，HSC）活化是肝纤维化发生、发展的核心。目前，HSC活化早期机制尚不明晰。近期发现基因Yap（Yes-associated protein）启动HSC早期活化，Hedgehog（Hh）信号促进HSC活化及肝纤维化，Yap与Hh信号在一些疾病调控中相互促进，据此推断Yap与Hh信号相互促进启动HSC活化诱导肝纤维化。我们前期初步发现Yap与斑马鱼肝纤维化相关。本项目中，运用iCRISPR-Cas9建立可诱导肝脏特异敲除Yap转基因斑马鱼，在肝纤维化刺激下结合HSC标记品系，从形态、病理组织及基因表达水平系统论证Yap启动HSC活化及诱发肝纤维化，探究Yap与Hh信号在其中的相互作用。本结论将补充HSC活化机制，并为肝纤维化早期诊断及抗纤维化药物研究提供实验基础。

肝纤维化是慢性肝病发展的必经阶段，及早发现与治疗对肝重病防治具有重要意义。近年发现Yap驱动肝星状细胞活化，但其在体内水平与肝纤维化发生的相关性尚不明晰。Hedgehog（Hh）信号是参与肝纤维化的重要通路，其信号分子与Yap在其他疾病中有相互作用，但Hh信号与Yap在肝纤维化中的相互作用仍未阐明。本项目运用硫代乙酰胺诱导斑马鱼胚胎及成鱼肝纤维化，通过吗啉代在胚胎水平敲除基因Yap，并分别运用Yap抑制剂维替泊芬及Hh信号抑制剂环巴胺，在生物信息学分析、病理组织及基因表达水平探索Yap在肝纤维化中的作用及其与Hh信号的相关性。转录组学结果表明Yap是斑马鱼胚胎肝脏正常发育的重要基因，胚胎Yap基因敲除导致Hh信号分子表达的显著性异常；病理结果表明胚胎Yap基因的抑制对TAA诱导肝脏病变具有减轻作用，但并不能抑制肝纤维化进程；基因表达结果表明Yap基因敲除对TAA诱导肝纤维化特征因子的变化具有抑制作用，Yap与Hh信号分子Gli1在TAA诱导肝纤维化过程中具有显著相关性，而与Shh、Smo无显著相关性。此外，本研究发现Yap辅助因子Wbp2在TAA诱导肝纤维化的发生过程中具有重要作用。本研究结论为肝纤维化早期诊断及抗纤维化药物研究提供实验基础。