MAPK、RhoA/ROCK在SHH调控RA滑膜病变过程中所扮演的角色

Rheumatoid arthritis (RA) is an autoimmune disease characterised by panarthritis, and this disease has a high incidence and high morbidity. Our previous and other relevant studies have shown that abberant activation of Sonic Hedgehog (SHH), MAPK and RhoA/ROCK signaling pathway play key roles in RA synovial hyperplasia. Blocking SHH signaling pathway resulted in inhibition of RA-FLS proliferation and migration. However, the exact mechanism is not elucidated. Based on the previous findings, we will explore and answer the next questions in this study: (1) in vivo, SHH gene overexpression and signaling pathway agonist are utilized in two animal models (collagen induced arthritis（CIA）rats and severe combined immunodeficient (SCID) mice into which human RA FLS and cartilage are grafted), and whether blocking MAPK or RhoA/ROCK signaling pathway has any effects on synovitis and cartilage erosions caused by abberant SHH signaling activation will be investigated. (2) in vitro, whether MAPK or RhoA/ROCK signaling pathway inactivation will influence RA-FLS proliferation or migration caused by SHH signaling overexpression will be explored. Our study will further reveal the exact mechanism of SHH signaling pathway in RA synovial hyperplasia and provide evidence for developing new drug targeting SHH signaling for the treatment of RA.

类风湿关节炎（RA）是以多关节炎为主要临床表现的自身免疫性疾病，具有高发病率和高致残率的特性。我们和其它相关研究表明: Sonic Hedgehog（SHH）、MAPK、RhoA/ROCK等信号通路异常与RA关节滑膜病变存在着密切的关系；抑制SHH信号通路能抑制成纤维样滑膜细胞(FLS)的增殖和迁移，但具体的分子机制未明。本研究拟在现有工作基础上，(1) 采用基因过表达或化学药物激动剂激活SHH信号分子后，观察MAPK、RhoA/ROCK失活对胶原诱导的关节炎大鼠模型和人RA FLS-软骨-严重联合免疫缺陷（SCID）小鼠模型的滑膜炎症和软骨破坏的影响；（2）采用离体RA FLS细胞模型，观察MAPK、RhoA/ROCK信号失活对SHH引发RA FLS增殖与迁移的影响。本项目将有利于进一步阐明SHH参与调控RA滑膜病变进程的分子作用机制，为开发治疗RA新药寻找新的靶点。

类风湿关节炎（RA）是以对称性多关节炎为主要表现的慢性自身免疫性疾病。滑膜过度增生、血管翳形成是RA关节破坏的主要原因。因此，调控成纤维样滑膜细胞（RA-FLS）增殖、迁移和侵袭可能是预防和治疗关节破坏的新方法。本课题组前期研究已表明SHH信号通路与RA关节滑膜增殖、迁移密切相关。本研究通过体内和体外实验，进一步探讨SHH信号通路调控RA-FLS增殖、迁移的分子机制。.研究内容包括：（1）采用RA-FLS 细胞模型，观察 MAPK、RhoA/ROCK 信号失活对 SHH 引发 RA-FLS 增殖、迁移和侵袭的影响。（2）采用基因过表达的方式激活SHH 信号分子，观察 MAPK失活对胶原诱导的关节炎 （collagen-induced arthritis, CIA）小鼠模型和人 RA-FLS-软骨-严重联合免疫缺陷（severe combined immunodeficiency, SCID）小鼠模型软骨破坏的影响。.体外实验结果表明SHH信号通路活化可促进RA-FLS增殖、迁移和侵袭，促进RA-FLS分泌IL-6、IL-8等促炎细胞因子。SHH信号通路可进一步活化MAPK/ERK、p38-MAPK和RhoA/ROCK信号。在SHH活化的基础上阻断MAPK/ERK、p38-MAPK和RhoA/ROCK信号可显著抑制RA-FLS增殖、迁移、侵袭。体内实验结果表明抑制SHH信号通路可减轻关节炎表现，减轻关节滑膜炎症和关节骨破坏。SHH过表达导致CIA小鼠关节炎表现更严重，促进关节滑膜炎症和关节骨破坏，提示抑制SHH信号通路可有效缓解关节炎。在SHH过表达的基础上阻断p38-MAPK可显著减轻小鼠关节炎表现，并减轻关节滑膜炎症和关节骨破坏，提示SHH信号通路可能通过p38-MAPK信号促进关节炎发病。此外，通过人 RA-FLS-软骨-严重联合免疫缺陷小鼠模型，我们发现抑制SHH信号通路可阻止RA-FLS侵袭软骨，SHH过表达显著促进RA-FLS迁移，促进RA-FLS所致软骨损伤。在SHH过表达的基础上阻断p38-MAPK可减少RA-FLS迁移，并降低RA-FLS侵袭软骨的程度。.本项目进一步阐明 SHH 可能通过活化MAPK/ERK、p38-MAPK和RhoA/ROCK信号参与调控 RA 滑膜病变和关节骨破坏，为开发靶向SHH信号通路用于治疗RA的新药提供基础。