dnTGF Beta RII Mice and PBC

描述(申请人提供)：原发性胆汁性肝硬变(PBC)是一种胆道特有的自身免疫性疾病，其特征是汇管内淋巴细胞渗入、抗线粒体抗体(AMAs)和选择性地破坏胆管上皮。尽管PBC通常被认为是一种典型的自身免疫性疾病，在定义PBC患者的晚期自身免疫效应因子(自身抗体、T细胞和B/T自身表位)方面也取得了重大进展，但这些数据尚未转化为新的治疗方法。在人类PBC中有一个延长的沉默的临床前阶段，因此，导致胆道损害的最早事件在很大程度上是未知的。发病和临床症状之间的这种差距阻碍了人们理解导致自我耐受障碍的事件的努力。我们的实验室将利用一种独特的PBC小鼠模型，即在CD4启动子控制下表达显性负向转化生长因子受体II基因的小鼠。这些小鼠出现强烈的炎症性胆道疾病和100%的AMA外显性。我们在当前资助期间的进展导致了重要的、新颖的、在某些情况下令人惊讶的结果，使我们能够解决三个关键领域，这三个领域有可能确定导致违反耐受性、胆管炎和肝纤维化的免疫病理学。首先，CD8T细胞介导胆道病理，更重要的是，KLRG1+效应CD8T细胞亚群聚集在肝脏中，但仅在存在缺陷的dnTGF-？RII Tregs的情况下。我们的目标将是确定KLRG1+的表型，其传播疾病的能力，以及Treg介导的对这一关键细胞亚群的控制机制。其次，我们已经证明，在dnTFbRII小鼠中，IL-12p35的缺失不仅会导致门脉炎症和胆管损伤，还会导致纤维化，并伴随着一种独特的细胞因子 侧写。我们将利用这一观察并连续监测这些事件，以确定在功能失调的转化生长因子信号转导过程中病理细胞因子的来源，并通过利用缺乏IL-17A、IL-17F、IL-22、IL-23p19或IL-17RA的转基因dn转化生长因子RII小鼠以及独特的骨髓嵌合小鼠模型，确定在慢性免疫反应过程中细胞因子如何交叉调节IL-17信号转导。最后，我们发表的数据表明，microRNA失调在自身反应性CD8T细胞介导的胆道病理中起主要作用。我们现有的模型和新提出的方法将使我们能够纠正这种失调，并测试正确的miRNA生物合成对T细胞激活状态的影响，更重要的是，对免疫病理学的影响。我们认为，这项研究的结果将为深入了解CD8效应器介导的损伤的作用机制提供机会，将为建立早期免疫介导的纤维化事件的生物网络提供机会，并最终提供关于microRNA在自身免疫性胆管炎中作用的关键机制信息。重要的是，我们相信这些数据可能会确定治疗靶向的新途径。

DESCRIPTION (provided by applicant): Primary biliary cirrhosis (PBC) is a biliary specific autoimmune disease characterized by lymphocytic infiltrates of portal tracts, anti-mitochondrial antibodies (AMAs) and selected destruction of the biliary epithelium. Although PBC is often considered a model autoimmune disease and there have been significant advances in defining the late stage autoimmune effectors (autoantibodies, T cells, and B/T autoepitopes) in PBC patients, such data has not been translated to new therapies. There is an extended silent preclinical phase in human PBC and, as such, the earliest events that lead to biliary damage are largely unknown. This gap between onset and clinical symptoms has frustrated efforts to understand the events that lead to breach of self-tolerance. Our laboratories will take advantage of a unique murine model of PBC, mice that express a dominant-negative TGF-ß receptor II gene under control of the promoter for CD4 (dnTGF-ßRII). These mice develop a robust inflammatory biliary disease and 100% penetrance of AMAs. Our progress during the current period of funding has led to important, novel and in some cases surprising results that allow us to address three critical areas that have the potential to define the immunopathology leading to breach of tolerance, cholangitis and hepatic fibrosis. First, CD8 T cells mediate biliary pathology and, more importantly, the KLRG1+ effector CD8 T cell subset accumulates in the liver, but only in the presence of defective dnTGF-ßRII Tregs. Our goal will be to define the KLRG1+ phenotype, its ability to transfer disease, and the mechanism of Treg-mediated control of this critical cell subset. Second, we have shown that deletion of IL-12p35 in dnTGF-ßRII mice leads not only to portal inflammation and bile duct damage, but also to fibrosis with a distinct cytokine profile. We will take advantage of this observation and serially monitor these events to define the sources of pathologic cytokines in the course of dysfunctional TGF-ß signaling as well as define how IL-17 signaling is cross-regulated by cytokines in the course of a chronic immune response by taking advantage of transgenic dnTGF-ßRII mice that lack IL-17A, IL-17F, IL-22, IL- 23p19 or IL-17RA in addition to unique bone marrow chimeric mouse models. Finally, our published data show that microRNA dysregulation plays a major role in autoreactive CD8 T cell mediated biliary pathology. Our existing models and novel proposed methods will allow us to correct this dysregulation and to test the effect of corrected miRNA biosynthesis on T cell activation status, and, more importantly, on immunopathology. We submit that the results of this proposal will provide insight into the mechanisms of action of CD8 effector mediated damage, will provide the opportunity to develop a biologic network of the earliest immune mediated fibrotic events and finally critical mechanistic information on the role of micro- RNA in autoimmune cholangitis. Importantly, we believe these data will potentially identify new pathways for therapeutic targeting.