趋化因子受体CXCR3在原发性胆汁性肝硬化发病机制中作用的研究

Primary biliary cirrhosis(PBC) is an organ-specific autoimmune liver disease characterized by the destruction of small intrahepatic bile ducts with portal inflammation,leading to liver cirrhosis.However,the precise nature of the autoimmune effector mechanisms of biliary ductular damage remains unclear.C-X-C chemokine receptor type3(CXCR3) is one of chemokine receptors, highly expressed on activated T cells,and is thought to play an important role in the recruitment of T cells to sites of inflammation.T cells have been reported to play a key role in development of PBC.CD8+T cells infliltrated the portal tract and specifically targeted bile duct cells.Although CD8+T cells appeared to be a major determinant in the pathogenesis of PBC in previous studies as adoptive transfer of CD8+ but not CD4+T cells from transforming growth factor beta receptor II (dnTGF-βRⅡ) mice into B6/Rag1-/- mice led to liver histopathology remarkably similar to PBC,it hasn't been reported whether CXCR3 and its ligands were crucial in directing CD8+T cells to liver in PBC.In present study, we propose that CXCR3 and its ligands mediate the recruitment of T cells to liver in PBC. Our previous study suggested that there was a marked increase of the level of plasma IP-10 and the frequency of CXCR3-expressing cells in periheral blood of poly I:C induced PBC model compared to controls.Further,CXCR3-positive cells were found in the portal areas of diseased livers.Knockout of CXCR3 might delay the PBC model disease progression..The next step,we would perform a series of experiments to determine the important role of CXCR3 and its ligands in pathogenesis of PBC.We would examine expression of CXCR3 and its ligands on liver,serum and peripheral blood mononuclear cells of dnTGF-βRII mice and PBC patients based on our PBC patients database by various methods,such as Enzyme-Linked Immunosorbent Assay(ELISA),flow cytometry,immunohistochemistry,western boltting and real-time quantitative polymerase chain reaction(PCR) etc.CD8+T cells were purified and transferred from dnTGF-βRⅡCXCR3-/- mice into Rag1-/- mice to determine whether CXCR3 were crucial in recruiting CD8+ T cells to liver in PBC model.In vitro transwell assays were also used to study chemotaxis of CXCR3 in PBC.Treatment of anti-CXCR3 blocking antibody would be applicated on PBC murine models compared with untreated controls.In addition,further research would be needed to understand the downstream and upstream signaling pathways regulating CXCR3 and its ligands by western blotting method etc.In conclusion,we will further investigate the important role of CXCR3 and its ligands in pathogenesis of PBC and look for a class of novel interventions against PBC by the chemokine and receptor in this study.

原发性胆汁性肝硬化（PBC）主要表现为肝内小胆管进行性破坏伴门脉炎症性改变，发病机制未明，治疗药物单一，最终导致纤维化及肝硬化。目前已有研究证明CD8+T细胞在PBC的发病中起至关重要的作用，而CD8+T细胞通过何种机制迁徙至肝脏发挥作用尚无报道。CXCR3是主要表达在活化T细胞上的趋化因子受体，本课题旨在研究CXCR3在PBC发病中所发挥的重要作用。.本课题将在我们前期研究的基础上，应用PBC患者数据库的平台和国际公认的小鼠模型，检测CXCR3及配体在大样本PBC患者和dnTGF-βRⅡ小鼠模型血清和肝脏中的表达，验证PBC发病中CXCR3的重要作用，应用体外趋化性检测和体内转输方法确定致病性CD8+T是否通过CXCR3及其配体迁徙至肝脏，研究CXCR3对T细胞活化的影响及受体活化后的信号转导通路，进一步阐明PBC的致病机制,并应用CXCR3拮抗剂注射PBC模型，探索治疗PBC的新方法。

原发性胆汁性肝硬化（PBC）主要表现为肝内小胆管进行性破坏伴门脉炎症性改变，治疗药物单一，最终导致纤维化及肝硬化，研究其发病机制利于寻找新的治疗方法。目前研究已证明T 细胞尤其CD8T细胞在PBC致病中起重要作用，然而CD8T细胞通过何种机制迁移至肝脏浸润以及如何发挥致病作用国内外尚无报道。CXCR3是主要表达在效应T细胞上的趋化因子受体，我们前期研究发现表达CXCR3的CD8T细胞在PBC模型鼠dnTGF-βRⅡ小鼠肝脏中显著多于野生型小鼠，并随疾病的发展而逐渐增多。本项目将利用PBC模型鼠和CXCR3缺失的PBC模型鼠对CXCR3在PBC中的作用机制予以探究，具体内容如下： 1）明确CXCR3缺失后PBC模型小鼠的疾病发展程度尤其是肝脏中CD8T细胞浸润的程度发生怎样的变化；2）探究CXCR3是否通过趋化作用招募致病性的CD8T细胞在肝脏中聚集从而发挥致病作用；3）进一步研究CXCR3是否通过调控CD8T细胞的活化状态以及功能的发挥从而影响CD8T细胞的致病性并阐明其具体机制。