【摘要】 在发现了GADD45β在类风湿关节炎(rheumatoid arthritis,RA)病灶局部组织细胞中、CD4+T细胞表达增高并参与介导IFN-γ产生的基础上,进一步探讨GADD45β参与RA的其他机制。用siRNA干扰人PBMC中GADD45β基因表达。Real-time PCR检测GADD45β和凋亡相关基因的表达格局。用RA患者滑膜液(RA synovial fluid,RA SF)刺激GADD45β基因敲除的健康人PBMC并用流式细胞仪检测细胞凋亡。结果RA患者的SFMC中T细胞凋亡减少。用SF刺激正常人PBMC时细胞凋亡减少。经siRNA干扰后PBMC中GADD45β的表达明显降低,同时细胞凋亡增加。同时检测与凋亡相关基因发现SF刺激后Bcl-2分子在凋亡的细胞中表达明显降低,而Fas-FasL、Bcl-2家族其他分子如Bcl-xl、Bax、Bim等变化不明显。GADD45β参与介导RA的炎症性T细胞凋亡,而Bcl-2分子参与了由GADD45β介导抗凋亡作用,而这一作用与RA患者滑膜液中炎症细胞能够长期存活并介导炎症可能有密切关系。更多还原

【Abstract】 Based on the discovery if the growth arrest and DNA damage factor 45β(GADD45β) in lesions of local tissue cells and the increased expression of CD4+ T cells mediating the production of IFN-γ,the mechanism of their roles participating pathogenesis of rheumatoid arthritis(RA) was further investigated.The expression of GADD45β in PBMC and the apoptosis-related genes(Bcl-2,BclxL,Bax,Fas and FasL) mRNAs were analyzed by real-time PCR and flow cytometry.PBMC from healthy individuals was cultured with synovial fluid from RA patients and the percentage of apoptotic cells were analysed by staining with annexin V and PI.The CD4+/CD8+ T cells in PBMC were identified by flow cytometry and special staining with specific antibodies.It was found that the number of apoptotic CD4+ T cells from synovial fluid of RA patients were obviously decreased in comparison with those from PBMC and the synovial fluid of RA patients could inhibit apoptosis of CD4+ T cells.Furthermore,by using siRNA to silence the expression of GADD45β and to stimulate the production of synovial fluid,apoptosis of CD4+ T cells could be demonstrated.As demonstrated by relative apoptosis gene profile assay,the expression of Bcl-2 was high in anti-apoptotic CD4+ T cells co-cultured with synovial fluid,while those of Bcl-xl and Fas showed no obvious change.The same result could be demonstrated by using the special staining of cells with specific antibodies.From these observations,it is apparent that GADD45β participates and mediates apoptosis of inflammatory T cells in RA.While the Bcl-2 molecule is involved in the anti-apoptotic action,which may be related to the survival of inflammatory cells in synovial fluid for a longer time or to mediate the inflammatory reactions.更多还原