Murphy E P, McEvoy A, Conneely O M, Bresnihan B, FitzGerald O
Department of Rheumatology, Education and Research Center, St. Vincent's University Hospital, Dublin, Ireland.
Arthritis Rheum. 2001 Apr;44(4):782-93. doi: 10.1002/1529-0131(200104)44:4<782::AID-ANR134>3.0.CO;2-H.
To examine the regulation and mode of action of peripheral corticotropin-releasing hormone (CRH) in human inflammatory arthritis.
CRH messenger RNA (mRNA) levels were measured in normal and inflamed synovial tissue and in primary synoviocytes prior to and following cytokine stimulation. Primary synoviocytes were transiently transfected with CRH promoter/reporter constructs, and promoter activity in response to cytokines was assessed. Immunohistochemical staining established CRH receptor expression, and Northern blot analysis confirmed that the nuclear transcription factors NUR77 and NURR1 contributed to synovial CRH receptor-mediated signaling. Primary synoviocytes were treated with pro- and antiinflammatory mediators, and the time course of NURR1 and NUR77 modulation was examined. Nuclear extracts were analyzed by electrophoretic mobility shift assay to determine NURR1 binding to the CRH promoter/enhancer.
CRH mRNA was up-regulated in the synovial tissue in rheumatoid arthritis (RA), psoriatic arthritis (PsA), and sarcoid arthritis, but not in normal synovium. Inflammatory cytokines, such as interleukin-1beta and tumor necrosis factor alpha, enhanced the transcriptional activity of the human CRH promoter and increased levels of CRH mRNA in primary synoviocytes. Synovial CRH functioned in a paracrine manner to induce NURR1 and NUR77. NURR1 was abundantly expressed in the inflammatory cells of both RA and PsA synovium. NURR1 and NUR77 were differentially regulated, and NURR1 was the major cytokine-regulated member of the NURR subfamily as well as the mediator of cytokine- and CRH-dependent inflammatory responses in synovium. Furthermore, glucocorticoids dramatically suppressed cytokine- and CRH-induced synovial NURR1 mRNA.
These data demonstrate the involvement of the transcription factor NURR1 in the regulation of CRH expression and activity in human inflammatory arthritis.
研究外周促肾上腺皮质激素释放激素（CRH）在人类炎性关节炎中的调控及作用模式。
在细胞因子刺激前后，检测正常及炎性滑膜组织和原代滑膜细胞中CRH信使核糖核酸（mRNA）水平。用CRH启动子/报告基因构建体瞬时转染原代滑膜细胞，评估细胞因子刺激后的启动子活性。免疫组织化学染色确定CRH受体表达，Northern印迹分析证实核转录因子NUR77和NURR1参与滑膜CRH受体介导的信号传导。用促炎和抗炎介质处理原代滑膜细胞，检测NURR1和NUR77调节的时间进程。通过电泳迁移率变动分析检测核提取物，以确定NURR1与CRH启动子/增强子的结合情况。
类风湿关节炎（RA）、银屑病关节炎（PsA）和结节病关节炎患者的滑膜组织中CRH mRNA上调，而正常滑膜组织中未上调。白细胞介素-1β和肿瘤坏死因子α等炎性细胞因子可增强人CRH启动子的转录活性，并增加原代滑膜细胞中CRH mRNA水平。滑膜CRH以旁分泌方式诱导NURR1和NUR77。NURR1在RA和PsA滑膜的炎性细胞中大量表达。NURR1和NUR77受到不同调节，NURR1是NURR亚家族中主要受细胞因子调节的成员，也是滑膜中细胞因子和CRH依赖性炎症反应的介质。此外，糖皮质激素可显著抑制细胞因子和CRH诱导的滑膜NURR1 mRNA表达。
这些数据表明转录因子NURR1参与人类炎性关节炎中CRH表达和活性的调控。
