榼藤调控A20/NF-κB信号通路的活性成分解析及其抗类风湿关节炎作用机制研究

Rheumatoid arthritis (RA) as a chronic autoinflammatory is characterized by widespread joint inflammation. New treatment options have been used in clinical but few patients are reaching sustained remission, and refractory patients continue to be a problem. A20 as a potential target against RA could regulate the cytokines related to the immune-inflammatory response. The stems of Entada phaseoloides is a well-known traditional medicine for treatment of rheumatoid arthritis by some ethnic minority groups in south China, but its exact mechanisms are still unknown. Our preliminary studies strongly indicated that it may significantly attenuate arthritis through regulating the A20/NF-κB signaling pathway. To further investigate this hypothesis, two parts of work will be conducted in this project, as following: 1) Through HPLC, LC-MS techniques, the fingerprints and quantitative composition activity relationship will be established to identify the effective substances from E.phaseoloides, combined with different models for anti-inflammatory activity evaluation of components in vitro. 2) Whether and how it switch A20/NF-κB signaling pathway and result in changes of inflammatory cytokine levels in vivo and vitro will be defined by using behavior research, RT-PCR and Western blot techniques. Together, this project will extensively study A20/NF-κB signaling pathway in the etiology of RA and as a therapeutic target for RA treatment, and providing scientific data for application of substances from E. phaseoloides in RA management.

类风湿关节炎（RA）是一种自身免疫性疾病，具有高度致残性，现有药物因耐药性和选择局限性不能持久有效缓解RA症状，因此亟需深入开展抗RA药物开发研究。A20能调节RA炎症免疫反应的不同活性物质，综合调控NF-κB信号通路。课题组前期研究发现，南方民族地区常用药物榼藤能显著改善RA的症状，调控A20表达，但其抗RA的活性成分与作用机制尚待深入研究。本项目拟在前期工作基础上，以A20/NF-κB为切入点，1）采用HPLC和LC-MS等方法，建立榼藤的化学指纹图谱和代谢图谱；应用BMDM、RA-FLS等细胞模型对各组分进行活性评价，从体内外成分差异和谱效相关性角度，阐明榼藤治疗RA的活性成分组成和结构特征；2）应用行为学、RT-PCR、Western blot等检测手段，从分子、细胞、动物层次，多维度阐释榼藤活性成分抗RA的作用机制。以期为榼藤的临床合理用药和RA创新药物研发提供有益参考。

榼藤为豆科榼藤属植物榼藤Entada phaseoloides (Linn.)Merr.的干燥藤茎，具有强筋健骨，补益腰肾之功效，是南方民族地区最常用的药物之一，主治风湿麻痹及风湿骨痛，治疗RA疗效显著，但其药理作用仅是比类取象的自然哲学式学说，尚无其抗类风湿关节炎药效物质基础的科学阐释。本研究以榼藤为研究对象，1）LC-MS等方法，建立榼藤药效成分组的特征图谱并阐释其科学内涵； 2）建立CIA动物模型，以行为学、组织学、细胞和分子生物学等手段，从整体动物水平和细胞分子水平检测不同炎症/免疫因子的表达，相关蛋白和信号通路的调控作用，阐述榼藤活性成分抗RA的确切作用机制。研究发现，以榼藤子酸为其主要苷元的三萜皂苷为其治疗类风湿关节炎的主要药效成分（简称ES）。ES能有效降低CIA大鼠的关节指数，抑制其关节肿胀、提高机械痛阈值，改善CIA关节部位的炎性细胞浸润和关节软骨、松质骨损伤，缓解CIA关节炎的进展。进一步研究发现ES能调节CD4+ /CD8+ T 淋巴细胞平衡，改善脾肿大；降低滑膜组织炎性因子mRNA表达水平、减少血清中IL-17, IL-1β 和TNF-α等促炎因子的释放，下调关节组织中IL-17和TNF-α的蛋白表达水平；调控关节组织A20蛋白表达，抑制MAPKs关键蛋白p38 和 Erk1/2的磷酸化水平，抑制脊髓组织中p38 的磷酸化，进而起到治疗RA的作用。该研究结果为指导榼藤临床合理用药提供科学基础，亦为榼藤的再次开发和寻找基于A20靶点的抗类风湿关节炎化合物实体提供理论支撑。