基于Adam8介导的胞外微环境病变研究体外培育牛黄改善胆汁淤积性肝损伤的机制

胆汁淤积性肝损伤（CLI）广泛存在于各种急、慢性肝病中，中医将其归属于“黄疸”范畴。CLI发病机制复杂，传统聚焦于改善肝细胞内胆汁酸失衡的药物疗效欠佳，调控胞外微环境病变成为近年来的研究热点。我们前期发现：CLI机体内疏水性胆汁酸累积可上调肝细胞Adam8的表达并与胞外炎症、增生和纤维化病变有关，中药体外培育牛黄（CBS）可下调Adam8而逆转上述异常。国内外研究显示Adam8是一种膜脱落酶，可通过向胞外域脱落相关底物参与细胞间信号交互。据此假说：CLI发病中，疏水性胆汁酸上调肝细胞Adam8并介导底物向胞外域脱落，促进胞外微环境炎症、增生和纤维化病变，而CBS可通过干预Adam8显著逆转。本课题拟从整体、细胞和分子水平，运用基因功能获得与缺失、血清药理学、血清药物化学等技术，阐明CBS干预Adam8脱落底物缓解CLI胞外微环境病变的作用机制及物质基础，为CLI提供新的治疗药物和靶点。

Cholestatic liver injury (CLI) widely exists in all kinds of acute and chronic liver diseases, which belongs to "jaundice" in Traditional Chinese Medicine. The pathogenesis of CLI is complicated, and drugs traditionally focusing on bile acid homeostasis in hepatocytes are not effective. The regulation of extracellular microenvironment has become a hotspot in recent years. We previously found that the accumulation of hydrophobic bile acids induced the upregulation of Adam8 in hepatocytes, which was correlated to extracellular inflammation, proliferation, and fibrosis in CLI, while Calculus Bovis Sativus (CBS) could downregulate Adam8 expression and significantly reverse the above abnormalities. Domestic and foreign studies have shown that Adam8 is a membrane shedding enzyme which participates in intercellular signal interaction by ectodomain shedding of related substrates. Based on these, we hypothesized that hydrophobic bile acids upregulate the expression of Adam8 in hepatocytes and mediate the ectodomain shedding of substrates, which promote inflammation, proliferation and fibrosis of the extracellular microenvironment, while CBS can significantly reverse these by intervening the expression of Adam8. This study intends to use techniques, such as overexpression- and knockout-genes, serum pharmacology, and serum medicinal chemistry, to clarify the mechanism and material basis of CBS in improving the extracellular microenvironmental pathology of CLI by intervening Adam8-mediated shedding from the animal, cellular and molecular levels, which will provide new therapeutic drugs and targets for CLI.