人参总皂苷通过Hippo信号通路重塑肝脏免疫微环境治疗自身免疫性肝炎的机制研究

There’s Study found that Myeloid-derived suppressor cells may be the key factor of the body's immune regulation，YAP which is the downstream factor Hippo pathways can activate the MDSCs, and glucocorticoid inhibits the Hippo-YAP pathway to suppress immune. But the role of MDSCs in autoimmune hepatitis and the relationship with immunosuppression related pathways is unclear. Previous work showed that ginseng total saponins can increase GR, then inhibiting the Hippo pathway to activate MDSCs, which shows have good immune inhibition, so we speculate that GSS may be the agonist of MDSCs. Therefore, this project adopts the cell culture and animal experiment of autoimmune hepatitis, to investigate the relationship between the Hippo-YAP and MDSCs activation，the influence of GR on Hippo pathway and its key downstream factors, thereby we further explore the mechanism of GSS reshaping the immune microenvironment. We want to confirmed that: ①the key role of MDSCs in autoimmune hepatitis ② the correlation between the Hippo signaling pathway and MDSCs activation ③GSS can activate MDSCs through Hippo-YAP signaling pathways by the regulation of GR to reshape the liver immune microenvironment. In order to explore the prevention and treatment of autoimmune hepatitis, and particularly for searching the new targets and mechanisms of the effective Chinese medicine monomer.

研究发现MDSCs可能是机体免疫调节的关键因子，Hippo调控的下游因子YAP可活化MDSCs，糖皮质激素能抑制Hippo-YAP通路从而抑制免疫。但MDSCs在AIH中的作用及免疫相关调控机制仍不清楚。前期工作表明人参皂苷具有GC样作用，可上调GR表达，是GC的增效剂。预实验证实GSS能够抑制Hippo通路从而激活MDSCs发挥免疫抑制作用，推测GSS可能是治疗AIH的有效药物。为此，本项目采用细胞和免疫性肝损伤动物模型，探讨Hippo-YAP与MDSCs活化的关系及GR的调控作用，在此基础上初步探讨GSS重塑免疫微环境治疗AIH的作用机制。拟证实:①自身免疫性肝炎中MDSCs的关键作用；②Hippo信号通路与MDSCs活化的关系；③GSS通过GR调控Hippo-YAP信号通路激活MDSCs重塑肝脏免疫微环境发挥保肝抗炎的作用机制。课题对自身免疫性肝炎防治、发现疗效确切的药物提供实验依据

自身免疫性肝炎（AIH）是一种基于免疫应答缺陷而诱导的进行性肝实质性炎症性疾病。目前，临床上缺乏特效药，糖皮质激素（GC）仍是AIH治疗的首选药物。然而，GC的长期应用带来的副作用限制了它的临床应用。在国家自然科学基金的支持下，本项目通过构建ConA诱导的小鼠AIH模型及体外MDSCs和T细胞共培养体系，并根据不同实验目的分别采用不同药物进行体内外干预，阐明Hippo通路在AIH中的活性及与MDSCs/T细胞的相关性，以及GR治疗AIH的可能作用机制，并在此基础上初步探讨了GSS对AIH紊乱的免疫微环境、Hippo通路及GR的影响，阐明GSS缓解AIH肝损伤的机制。研究发现：①MDSCs的增殖活化对AIH的发生发展具有显著影响，促进MDSCs增殖活化可以抑制过度激活的免疫系统，维持免疫微环境稳态；②在AIH中Hippo通路存在表达变化，Hippo-YAP/TAZ-TEAD通路对MDSCs及免疫T细胞的增殖活化具有调节作用；③在AIH中GR表达变化对Hippo-YAP/TAZ-TEAD信号通路具有调节作用，从而影响MDSCs及T细胞的分化，进而发挥免疫抑制的作用；④GSS在AIH中可以通过GR途径，发挥糖皮质激素样作用，并进一步激活Hippo-YAP/TAZ-TEAD信号通路，进而促进MDSCs的增殖，增强其向M-MDSCs亚型分化，调节T细胞的增殖分化从而重建免疫微环境稳态，发挥治疗AIH的作用。本课题的完成，不仅证实了GSS新的药理作用机制和作用靶点，还进一步验证了GSS可能是人参调节免疫、发挥抗炎保肝的共同药理学作用的物质基础。为人参在中医临床多病症的应用提供一些现代药理学理论和实验支持，有望作为未来临床治疗AIH的潜在用药。