SUMO化相关蛋白对RA 关节滑膜细胞活化、迁移和侵袭的调控及其机制研究

Abnormal activation, migration and invasion of fibroblast like synoviocytes (FLS) play a key role in the initiation and progress of rheumatoid arthritis (RA), however, the mechanisms contributing to those abnormal changes of biology are still poorly understood. In recent years, it was shown that small ubiquitin-related modifier (SUMO) participates in modulation of migration and invasion of several cell lines, and related proteins that regulate sumoylation may modulate cell migration via modifying Rho family proteins. Our previous studies demonstrated that Rho family proteins activation has an important role in regulating RA synovial inflammation, migration and invasion. Increased expression of PIAS3 and Ubc9 was found in RA synovial tissue and FLS, and is associated with migration and invasion of FLS. Therefore, based on our previous studies, we will further investigate the role of sumoylation on regulating activation, migration and invasion through modifying Rho family proteins in RA FLS. Furthermore, we will determine the in vivo effects of modulation of sumoylation-related proteins expression on migration, invasion of RA FLS, as well as on pathological change and clinical symptom of joint, by use of severe combined immunodeficient (SCID) mice and collagen-induced arthritis (CIA) model. Our results may provide evidence of the role of sumoylation-related proteins in synovial inflammation and joint destruction in RA, and will help to find new targets for RA treatment.

滑膜成纤维细胞（FLS）异常活化、迁移和侵袭在类风湿关节炎（RA）的发病和病情进展中起关键作用，但其机制尚不清楚。近年发现SUMO（small ubiquitin-related modifier）化修饰是调控细胞迁移、侵袭的重要因素；参与调控SUMO化的相关蛋白可能通过修饰Rho蛋白调节细胞迁移。我们前期发现Rho蛋白参与调控RA滑膜炎症、迁移和侵袭；SUMO化相关蛋白PIAS3和Ubc9在RA滑膜中表达增高，并且与滑膜迁移、侵袭密切相关。因此，基于我们以往的工作基础，本课题通过研究SUMO化相关蛋白对FLS活化、迁移和侵袭的调节作用及其是否通过Rho蛋白介导；并利用严重免疫缺陷和胶原诱导关节炎模型，观察体内调控SUMO化相关蛋白表达对FLS迁移、侵袭的影响以及关节病理损害和症状的改善作用，旨在研究SUMO化相关蛋白对RA滑膜炎症和关节破坏的调控作用，为研制新型RA治疗药物提供理论基础。

滑膜成纤维细胞（FLS）过度活化、增生和具有侵袭性是类风湿关节炎（RA）关节炎症和破坏持续进展的关键环节。本课题运用分子生物学和现代免疫学技术研究发现，RA患者关节滑膜组织和FLS中PIAS3、UBC9、SAE1/2和SUMO-1表达显著高于骨关节炎患者和正常对照组，而PIAS1、PIASx、PIASy表达在各组间则无明显差异。IL-1β和TNFα均能刺激RA滑膜成纤维细胞PIAS3、UBC9、SAE1/2和SUMO-1表达。利用shRNA或siRNA分别抑制PIAS3、UBC9、SAE1/2和SUMO-1蛋白表达能显著抑制RA FLS迁移、侵袭、细胞骨架重排以及基质金属蛋白酶和炎症因子分泌。进一步的机制研究发现，抑制PIAS3、UBC9、SAE1/2和SUMO-1蛋白表达能显著抑制Rac1/PAK1和RhoA/ROCK活性，以及Rac1和RhoA的SUMO化；而抑制Rac1/PAK1和RhoA/ROCK可抑制RA FLS的迁移、侵袭和炎症因子分泌，提示Rac1、RhoA通路介导PIAS3、UBC9、SAE1/2对RA滑膜的功能影响。利用CIA动物模型体内证实抑制关节腔内PIAS3、UBC9、SAE1/2蛋白表达能改善大鼠的关节病理损害和临床症状。上述研究提示PIAS3、UBC9、SAE1/2蛋白参与调控RA滑膜活化、迁移和侵袭，通过调控上述SUMO化相关蛋白表达可能是RA关节破坏治疗的新思路。