SIRT1 overexpression in the rheumatoid arthritis synovium contributes to proinflammatory cytokine production and apoptosis resistance
SIRT1 overexpression in the rheumatoid arthritis synovium contributes to proinflammatory cytokine production and apoptosis resistance
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DOI：
10.1136/ard.2010.148957
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发表时间：
2011-10-01
影响因子：
27.4
通讯作者：
Kyburz, Diego
中科院分区：
文献类型：
--
作者：
Niederer, Fabienne;Ospelt, Caroline;Kyburz, Diego
目的分析SIRT 1在类风湿关节炎（RA）患者滑膜组织和细胞中的表达，探讨SIRT 1在RA炎症和细胞凋亡中的作用。方法采用实时荧光定量PCR和Western blotting方法检测Toll样受体配体刺激RA患者滑膜组织和细胞前后SIRT 1的表达水平，肿瘤坏死因子α（TNF α）和白细胞介素1 β（IL-1 β）。免疫组织化学用于研究SIRT 1的定位。采用荧光激活细胞分选技术检测SIRT 1对细胞凋亡的影响。外周血单核细胞和类风湿性关节炎滑膜成纤维细胞（RASF）转染野生型或酶失活SIRT 1表达载体或siRNA靶向SIRT 1。采用ELISA法检测IL-6、IL-8和TNF α，研究SIRT 1在RA患者滑膜组织和细胞中的表达。结果与骨关节炎患者相比，RA患者滑膜组织和细胞中SIRT 1表达上调。TNF α刺激RASF和单核细胞导致SIRT 1的进一步诱导表达水平。SIRT 1沉默促进RASFs的凋亡，而SIRT 1过表达保护细胞免于凋亡。通过抑制剂、siRNA和SIRT 1的酶失活形式的过表达抑制SIRT 1酶活性降低单核细胞中脂多糖诱导的TNF α水平。结论TNF α诱导RA滑膜细胞SIRT 1过表达，通过促进促炎细胞因子的产生和抑制细胞凋亡，参与RA慢性炎症的发生。
Objective To analyse the expression of SIRT1 in synovial tissues and cells of patients with rheumatoid arthritis (RA) and to study the function of SIRT1 in inflammation and apoptosis in RA.Methods Levels of SIRT1 expression were analysed in synovial tissues and cells from patients with RA by real-time PCR and western blotting before and after stimulation with toll-like receptor ligands, tumour necrosis factor alpha (TNF alpha) and interleukin 1 beta(IL-1 beta). Immunohistochemistry was used to study the localisation of SIRT1. Fluorescence activated cell sorting analysis was performed to investigate the effect of SIRT1 on apoptosis. Peripheral blood monocytes and rheumatoid arthritis synovial fibroblasts (RASFs) were transfected with wildtype or enzymatically inactive SIRT1 expression vectors or with siRNA targeting SIRT1. Cytokine analysis of IL-6, IL-8 and TNFa were performed by ELISA to study the role of SIRT1 on proinflammatory mediators of RA.Results SIRT1 was found to be constitutively upregulated in synovial tissues and cells from patients with RA compared to osteoarthritis. TNFa stimulation of RASFs and monocytes resulted in further induced expression levels of SIRT1. Silencing of SIRT1 promoted apoptosis in RASFs, whereas SIRT1 overexpression protected cells from apoptosis. Inhibition of SIRT1 enzymatic activity by inhibitors, siRNA and overexpression of an enzymatically inactive form of SIRT1 reduced lipopolysaccharide-induced levels of TNFa in monocytes. Similarly, knockdown of SIRT1 resulted in a reduction of proinflammatory IL-6 and IL-8 in RASFs.Conclusion The TNF alpha-induced overexpression of SIRT1 in RA synovial cells contributes to chronic inflammation by promoting proinflammatory cytokine production and inhibiting apoptosis.