血管紧张素II受体及其信号对类风湿关节炎异常活化的巨噬细胞样滑膜细胞的调控作用

Angiotensin Ⅱ(AngⅡ) and receptors participate in the modulation of inflamation and immunity. Ang Ⅱ type 1 receptor (AT1R) blocker ameliorates the rheumatoid arthritis (RA) and experimental models progression, and improves the synoviocytes dysfunction and activation. Ang Ⅱtype 2 receptor (AT2R) mainly exerts counter-regulatory actions to AT1R. Our previous study indicated that AT2R agonist alleviated the synovitis, and AT1R/AT2R imbanlance promoted RA development. Based on rat collagen induced arthritis (CIA) and RA macrophage-like synoviocyte (MLS), the change of MLS dysfunction and activation, as well as the role of Ang Ⅱ receptors signaling and MAPKs cross-talk, were studied using the the laser confocal microscopy, electrophoretic mobility shift assay,co-immunoprecipitation,siRNA, and Ang Ⅱ receptors pharmacology tools. Also, the fluence of Ang Ⅱ receptors signaling on MLS dysfunction and activation was studied using AT1R or AT2R knock-out mouse. The designed work will illustrate the role of Ang Ⅱ receptors signaling on MLS activation, and provide evidence for AT2R for treating RA as novel target.

血管紧张素Ⅱ（AngⅡ）及受体参与炎症免疫调节。阻断AngⅡ1型受体（AT1R）缓解类风湿关节炎（RA）及动物模型炎症免疫反应，改善滑膜细胞活化、功能。AngⅡ2型受体（AT2R）及信号转导可拮抗AT1R功能。课题组发现，AT2R激动剂缓解滑膜炎，AT1R/AT2R失平衡促进RA进展。本项目利用大鼠胶原性关节炎（CIA）和RA患者巨噬细胞样滑膜细胞（MLS），采用激光共聚焦、免疫共沉淀、电泳迁移实验、基因表达谱芯片、siRNA及AT2R、AT1R药理学工具，研究RA的MLS活化、功能变化；探讨AT2R、AT1R信号转导及与MAPKs交叉对话在MLS活化、功能变化的作用；利用AT1R或AT2R敲除小鼠制备CIA模型，研究AT2R、AT1R信号对CIA的MLS活化、功能的影响。为揭示AngⅡ及受体信号对RA异常活化MLS的调节作用以及发现AT2R作为RA滑膜炎治疗靶点提供实验依据。

本项目以类风湿关节炎（RA）患者滑膜组织样本和动物模型为研究对象，研究血管紧张素Ⅱ（AngⅡ）通过1型受体（AT1R）和2型受体（AT2R）对巨噬细胞样滑膜细胞（MLS）的影响，探讨AT1R/AT2R信号传导失平衡对MLS的可能作用和分子机制，明确AT2R表达、功能操控通过MAPKs信号传导通路对关节滑膜炎中MLS的调控作用和对RA临床治疗的潜在应用价值。. 研究发现，RA患者外周血单个核细胞和关节滑膜巨噬细胞呈炎性状态，且AT1R、AT2R的表达异常增高。使用动物模型研究发现，AT2R药理学激动剂缓解大鼠胶原性关节炎（CIA）炎症免疫反应，改善炎症滑膜中巨噬细胞浸润，抑制滑膜炎巨噬细胞异常活化，促进滑膜巨噬细胞从促炎型向抗炎型的转化。进一步发现，在小鼠系统性敲除AT2R基因后，胶原抗体诱导关节炎（CAIA）诱导的小鼠炎症状况显著加剧，炎性细胞浸润增加，关节滑膜组织增生，关节间隙变窄、结构紊乱，关节面可见轻度的畸形。AT2R的缺失可能导致了单核细胞分化异常，出现了CD11bhiF4/80low细胞群并呈现炎性巨噬细胞的特点，可能是导致关节炎疾病恶化重要影响因素。活化AT2R后抑制LPS诱导的大鼠滑膜巨噬细胞的异常活化和分化，AT2R的活化能够下调NF-κB信号通路以及抑制MAPK信号通路中ERK的磷酸化。. 本项目揭示了AngⅡ及受体信号对RA异常活化MLS的调节是RA滑膜炎发病新的病理机制，发现AT2R可能成为RA滑膜炎新的治疗靶点提供实验依据，这为临床治疗类风湿关节炎及其研发创新治疗药物提出了新思路。