骨桥蛋白（OPN）抑制肠道抗菌肽表达促进慢加急性肝衰竭肠道稳态恶化的机制研究

肠道稳态恶化是介导慢加急性肝衰竭（ACLF）时系统性免疫反应（SIRS）发生及高死亡率的关键上游事件，但其发生机制一直少有探究。我们前期研究发现，急性肝衰竭及ACLF时，骨桥蛋白（OPN）是肝细胞释放的一种与SIRS反应有关的损伤相关分子（DAMP）。进一步研究发现，ACLF模型中肝细胞敲除OPN小鼠相较于对照组，肠道菌群数量及组成，SIRS反应及小鼠的死亡率均显著降低，且肠道抗菌肽表达明显增高而上皮细胞焦亡显著降低，提示OPN可能通过诱导肠道上皮细胞焦亡抑制抗菌肽表达，进而促进ACLF时肠道稳态恶化。拟进一步采用体外类器官培养肠道上皮细胞体系，分析OPN抑制肠道上皮细胞抗菌肽的机制，以及诱导肠道上皮细胞焦亡的受体及通路，明确其促进ACLF病理过程中肠道稳态恶化，SIRS发生的分子机制。探讨靶向OPN阻断肠道稳态恶化减轻SIRS反应及死亡率的可能性，为ACLF的防治提供新的策略和理论依据。

Dysbiosis of intestinal barrier and gut microbiota are upper key events and contributing to systemic immune response and high mortality during ACLF. Our recently research found that Osteopontin (OPN) is a new damage-associated molecular pattern (DAMP) from damaged hepatocytes in acute liver failure or ACLF. We further found that OPN is a key regulator of dysbiosis of intestinal barrier and gut microbiota in ACLF. In this proposal, we plan to identify the function and mechanism of OPN on intestinal mucosa and gut epithial cells, to determine the molecular mechanism of Dysbiosis of intestinal barrier and gut microbiota in ACLF. Meanwhile, given that the pyroptosis in gut tissues were much lower and anti-microbial-peptides were higher in inducible hepatocyte-specific knockout OPN mice compared to their control mice in ACLF models, suggesting that the mechanism of OPN promoted dysbiosis of intestinal barrier and gut microbiota was associated with its induction of pyroptosis in gut epithial cells. We further plan to adopt organoid live cells systems to elucidate the receptor and signaling pathways of OPN in gut epithial cells. Put together, these proposed studies will enable us to better understand the role and mechanisms of OPN in promotion of dysbiosis of intestinal barrier and gut microbiota, with the potential to develop new therapeutic strategy for ACLF.