m6A调控MMP-7/骨桥蛋白轴在胆道闭锁肝纤维化中的作用机制研究

进行性肝纤维化是胆道闭锁（biliary atresia，BA）终末期肝病的主要病因，具体机制不明。本项目前期发现m6A甲基化调控MMP-7表达，MMP-7、骨桥蛋白（osteopontin，OPN）在BA胆管上皮细胞特异性表达，且较对照组明显升高，两者之间呈明显正相关，且MMP-7、OPN的表达均与BA肝纤维化程度正相关；单细胞测序进一步揭示胆管上皮细胞分泌OPN促进肝星状细胞COL3A1表达，因此我们推测m6A调控MMP-7剪切OPN促进BA肝纤维化。本项目从3方面入手：①m6A对MMP-7的具体调控机制；②MMP-7对OPN的剪切作用；③MMP-7/OPN代谢轴在肝星状细胞活化及BA小鼠肝纤维化中的作用机制。本项目创新性的发现MMP-7的上游表观调控机制，并且拓展了MMP-7在BA肝纤维化中的分子机制。通过靶向干预MMP-7/OPN代谢轴，为今后缓解BA肝纤维化提供了有力的证据支持。

Progressive liver fibrosis is the main cause of end-stage liver disease in biliary atresia (BA) with unknown mechanism. We previously found that m6A methylation regulated the MMP-7 expression in BA, MMP-7 and osteopontin (OPN) were exclusively expressed in the biliary epithelial cells (BECs) of BA, and their expressions were significantly higher than those in the control group. Furthermore, MMP-7 was positively correlated with OPN, and both of their expressions were associated with the liver fibrosis of BA. Additionally, single-cell RNA sequencing revealed that BECs secreted OPN to promote COL3A1 expression in hepatic stellate cells. Therefore, it can be inferred that m6A regulated MMP-7 to hydrolyze OPN promoting BA liver fibrosis. This project was designed from three aspects: ① The specific regulatory mechanisms of m6A on MMP-7; ② The hydrolysis effect of MMP-7 on OPN; ③ The mechanism of MMP-7/OPN metabolic axis in the hepatic stellate cell activation and liver fibrosis of BA mice. This project innovatively discovers the upstream epigenetic regulation mechanism of MMP-7, and extends the molecular mechanism of MMP-7 in BA liver fibrosis. Targeting intervention of the MMP-7/OPN metabolic axis may provide convincing evidence for the future therapy to alleviate BA liver fibrosis.