Dickkopf-1通过调控调节性T细胞促进类风湿关节炎发病的分子机制研究

Rheumatoid arthritis (RA) is an autoimmune disease of high morbidity.The articular cartilage and bone destruction caused by continuous progress of synovial inflammation is considered to be the key to the development of RA. Recently, Dkk-1,the inhibitor of Wnt signaling, is focused more and more for the association with bone destruction in RA.However, whether DKK-1 lead to cellular immune abnormalities of RA is unclear. The prophase work of this research at home and abroad first found that Dkk-1 increase the number but impaired function of regulatory T cells in peripheral blood.The study suggested DKK-1 may stimulate abnormal immune response of T cells, promote bone destruction and synovial pannus formation in RA. The research projects to further reveal the roles and molecular mechanisms of DKK-1 on the differentiation and function of regulatory T cells from molecular, cellular, animal models and RA patients, and to explore the role of Dkk-1 in the signal transduction pathway of synovial pannus formation in RA,and then provide a further mechanism for understanding of DKK-1 pathogenic role in RA with collagen induced arthritis (CIA) mice and DKK-1 transgenic mice as a platform. This study will provide new clues for understanding the pathogenesis of RA, and be expected to provide new therapeutic targets for the treatment of RA.

类风湿关节炎（RA）是一种高度致残性自身免疫病，持续进展的滑膜炎导致关节软骨和骨的破坏被认为是RA疾病进展的关键。近年来，内源性Wnt通路拮抗剂DKK-1因与RA骨破坏密切相关而备受关注，然而，DKK-1是否导致RA细胞免疫的异常还不清楚。本课题组的前期工作在国内外首次发现DKK-1可以导致外周血调节性T细胞(Treg)数量显著增多但是功能受损，上述研究提示在RA中DKK-1可能兼具刺激T细胞异常免疫反应、促进滑膜血管翳生成和导致骨破坏的多重作用。本课题拟从分子、细胞、动物模型及RA患者四个层面进一步揭示DKK-1对Treg细胞的分化及功能的调控作用及分子机制；探索RA中DKK-1导致Treg细胞功能异常的信号转导通路；以胶原诱导关节炎小鼠和DKK-1转基因鼠为平台，验证在RA中Dkk-1对Treg细胞功能异常的调控作用。本研究将为深入理解RA发病机制提供新线索，也有望为RA治疗提供新靶点

类风湿关节炎（RA）是一种高度致残性自身免疫病，持续进展的滑膜炎导致关节软骨和骨的破坏被认为是RA疾病进展的关键。近年来，内源性Wnt通路拮抗剂DKK-1因与RA骨破坏密切相关而备受关注，然而，DKK-1是否导致RA细胞免疫的异常还不清楚。本课题组的前期工作在国内外首次发现DKK-1可以导致外周血调节性T细胞(Treg)数量显著增多但是功能受损，上述研究提示在RA中DKK-1可能兼具刺激T细胞异常免疫反应、促进滑膜血管翳生成和导致骨破坏的多重作用。本课题拟从分子、细胞、动物模型及RA患者四个层面进一步揭示DKK-1对Treg细胞的分化及功能的调控作用及分子机制；探索RA中DKK-1导致Treg细胞功能异常的信号转导通路；以胶原诱导关节炎小鼠和DKK-1转基因鼠为平台，验证在RA中DKK-1对Treg细胞功能异常的调控作用。检测RA患者和健康人血浆DKK-1和核因子κB受体活化因子配体（RANKL）水平，并分析其相关性。体外分离培养 RA 患者的成纤维样滑膜细胞（FLS），利用小干扰 RNA（siRNA）靶向抑制 DKK-1，并检测RA FLS表达RANKL的变化。构建胶原诱导性关节炎（CIA）小鼠模型，通过靶向DKK-1的腺相关病毒（AAV）载体进行RNA干扰（RNAi）治疗，使小鼠Dkk1基因沉默。观察及评价小鼠的关节炎累积发病率、关节炎评分、血清DKK-1水平及关节病理组织学评分。研究结果显示，RA患者血浆DKK-1和RANKL均高于健康人，RA患者的血浆DKK-1和RANKL呈正相关。靶向DKK-1的siRNA可有效抑制RAFLS的DKK-1表达，干扰效率 36.50%；同时可抑制RA FLS 的RANKL表达，上调OPG的表达。靶向抑制DKK-1的治疗组小鼠血清DKK-1水平显著低于对照组和健康小鼠。镜下观察治疗组病变关节处的免疫细胞浸润数、破骨细胞数及关节评分均减低。本研究证明了靶向抑制DKK-1的siRNA使RA FLS 的RANKL表达减低。首次证明了靶向抑制 DKK-1 的 RNAi 治疗可以有效缓解炎性关节炎模型小鼠的关节炎症。