RIP3介导的程序性坏死通路在自身免疫性肝炎巨噬细胞免疫炎症和耐受应答中的作用和机制研究

The immune inflammation and tolerant response to external antigens of liver macrophages are closely related to the pathogenesis of autoimmune hepatitis (AIH), but the mechanism is yet unclear. Recent evidences show that programmed necrosis mediated by receptor-interacting protein 3 (RIP3) plays a key role in regulating the functions and cell death of macrophages. In our previous study, we found that in AIH patients, the expression levels of RIP3 in the macrophages of liver tissues were correlated to the severity of liver injury, as well as the RIP3 expression of peripheral monocytes. Furthermore, we identified that RIP3 signaling was activated by lipopolysaccharide (LPS) and promotes the secretion of interlukin-6 (IL-6) in macrophages. Moreover, the activity of RIP3 was targeted by the immunosuppressant azathioprine. However, the mechanisms of RIP3 activation and the regulating effects on the functions of macrophages remains unclear. In this study, using primary monocytes in vitro and rip3-/ -mice in vivo, we will first analyze the effects of RIP3 activation on the differentiation of macrophages' surface molecules, the change cytokine profiles, and the regulation on the proliferation of Treg cells. Second, we will study the effects of enterogenous bacteria on the activity of RIP3 signaling of liver macrophages in the primary cells and mice. In addition, we will study the correlation between activities of RIP3 signaling associated molecules and the clinicopathology of AIH patients to explore the clinical values of RIP3 pathway. Taken together, this study will reveal the pathogenesis of AIH and provide new clues for clinical prevention and treatment.

肝脏巨噬细胞对外界抗原的免疫炎症和耐受应答与自身免疫性肝炎（AIH）发病密切相关，但机制未明。最近发现，RIP3介导的程序性坏死通路是调控巨噬细胞功能和死亡的关键通路。我们前期发现，AIH患者肝巨噬细胞和外周血单核细胞RIP3表达量与肝损伤程度平行；RIP3可被LPS激活促进巨噬细胞IL6分泌，且是免疫抑制剂硫唑嘌呤作用靶点。然而，RIP3活化的诱因和对AIH巨噬细胞功能的影响及其临床价值未明。本研究首先在细胞和RIP3-/-小鼠中分析RIP3活化对巨噬细胞表面分子、细胞因子和Th17/Treg分化的影响，从而评价RIP3对免疫炎症和耐受功能的调控；再在细胞和小鼠中分析肠源性细菌对肝巨噬细胞RIP3活性的影响，初步探讨RIP3活化原因；进而在AIH患者外周血和肝组织中分析RIP3活化与临床病理的相关性；评价RIP3通路相关标志物的临床应用前景。旨在探索AIH发病机制并为临床防治提供新线索。

自身免疫性肝炎（autoimmune hepatitis, AIH）是一种慢性进行性肝脏炎症性疾病，其发病机制尚未阐明,仍缺乏有效防治手段和疾病活动度监测指标。肝脏巨噬细胞对外界抗原的免疫炎症和耐受应答与自身免疫性肝炎发病密切关，RIP3介导的程序性坏死通路是调控巨噬细胞功能和死亡的关键通路。我们前期发现AIH患者肝脏巨噬细胞RIP3表达增加，但机制未明。在本项目中我们证明了：1. RIP3介导自身免疫性肝炎肝脏单核细胞来源巨噬细胞募集；2.RIP3阻断通过髓源性抑制细胞依赖机制预防免疫介导的肝炎；3. 微生态失调驱动的肠漏通过RIP3信号通路增强肝巨噬细胞的活化和募集；4.双岐乳杆菌B420通过调节肠道屏障和肝脏免疫细胞减轻自身免疫性肝炎。此外还对自身免疫性肝病相关的临床特征进行了统计分析，发现：1. 腹部淋巴结肿大是自身免疫性肝病的特征之一；2.AILD患者合并胆囊结石临床特征分析；3.应用常规体检指标组合预测肝病风险可以作为肝病的一种临床筛查模型；4.新HLA-DRB1等位基因增加原发性胆汁性胆管炎的疾病易感性风险。本项目结合临床样本发现，从RIP3信号通路入手，为探索自身免疫性肝病发病机制及临床防治提供了新线索，为自身免疫性肝病的临床干预提供了理论基础。成果以论文的形式提交，已在SCI期刊发表论文7篇，中文核心期刊8篇，使3名博士生获得系统的科研技能和扎实的知识基础，并促进了新疆和田地区的沟通发展和人才培养，为其培养了两名在读硕士。