Department of Pathology, Iwate Medical University, Morioka, Shiwa-gun, Japan.
Int J Rheum Dis. 2012 Feb;15(1):36-44. doi: 10.1111/j.1756-185X.2011.01656.x. Epub 2011 Sep 14.
A disintegrin-like and metalloproteinase with thrombospondin type 1 motif (ADAMTS)-4 and ADAMTS-5 play crucial roles in the cleavage of aggrecan. Several recent studies have demonstrated the effect of cytokines such as interleukin (IL)-1β, tumor necrosis factor-α and transforming growth factor-β on the expression of ADAMTS-4 and ADAMTS-5 in fibroblast-like synoviocytes (FLS). However, the effect of IL-6 remains unclear. The aim of this study is to investigate the expression of ADAMTS-4 and ADAMTS-5 in FLS of rheumatoid arthritis (RA) patients after IL-6 stimulation.
Immunohistochemical staining was performed to examine the expression and localization of ADAMTS-4 and ADAMTS-5 in RA synovium. FLS isolated from RA patients were stimulated by IL-6 and soluble IL-6 receptor (sIL-6R) in the presence or absence of anti-IL-6R antibody, and the expression levels of ADAMTS-4 and ADAMTS-5 messenger RNA (mRNA) were assessed using real-time polymerase chain reaction. Furthermore, the IL-6 signaling pathway for regulation of ADAMTS-4 and ADAMTS-5 was also examined.
Staining for ADAMTS-4 and ADAMTS-5 was mainly observed in the sublining layer of synovial membrane and pannus. The expression of ADAMTS-4 mRNA was increased by IL-6/sIL-6R, whereas that of ADAMTS-5 was decreased. Anti-IL-6R antibody suppressed the effect of IL-6/sIL-6R. Mitogen-activated protein kinase (MAPK)/extracellular signal-related kinase (ERK) kinase (MEK)1/2 inhibitor U0126 inhibited the effect of IL-6/sIL-6R on ADAMTS-4 mRNA expression in FLS. Signal transducer and activator of transcription 3 (STAT3) inhibitor parthenolide inhibited the effect of IL-6/sIL-6R on ADAMTS-4, and downregulated ADAMTS-5 expression.
These results suggest IL-6 may participate in cartilage destruction in RA as an inducer of ADAMTS-4 expression from FLS.
解整合素样金属蛋白酶与凝血酶 1 型基质金属蛋白酶（ADAMTS）-4 和 ADAMTS-5 在蛋白聚糖的裂解中发挥关键作用。几项最近的研究表明，细胞因子如白细胞介素（IL）-1β、肿瘤坏死因子-α 和转化生长因子-β 对成纤维样滑膜细胞（FLS）中 ADAMTS-4 和 ADAMTS-5 的表达有影响。然而，IL-6 的作用尚不清楚。本研究旨在探讨 IL-6 刺激后类风湿关节炎（RA）患者 FLS 中 ADAMTS-4 和 ADAMTS-5 的表达。
采用免疫组织化学染色法检测 RA 滑膜中 ADAMTS-4 和 ADAMTS-5 的表达和定位。用 IL-6 和可溶性 IL-6 受体（sIL-6R）刺激从 RA 患者中分离的 FLS，并在存在或不存在抗 IL-6R 抗体的情况下，采用实时聚合酶链反应评估 ADAMTS-4 和 ADAMTS-5 信使 RNA（mRNA）的表达水平。此外，还研究了 IL-6 信号通路对 ADAMTS-4 和 ADAMTS-5 的调节作用。
ADAMTS-4 和 ADAMTS-5 的染色主要观察到在滑膜膜的衬里下层和血管翳中。IL-6/sIL-6R 增加了 ADAMTS-4 mRNA 的表达，而 ADAMTS-5 的表达则减少。抗 IL-6R 抗体抑制了 IL-6/sIL-6R 的作用。丝裂原活化蛋白激酶（MAPK）/细胞外信号调节激酶（ERK）激酶（MEK）1/2 抑制剂 U0126 抑制了 IL-6/sIL-6R 对 FLS 中 ADAMTS-4 mRNA 表达的作用。信号转导和转录激活因子 3（STAT3）抑制剂白藜芦醇抑制了 IL-6/sIL-6R 对 ADAMTS-4 的作用，并下调了 ADAMTS-5 的表达。
这些结果表明，IL-6 可能作为 FLS 中 ADAMTS-4 表达的诱导剂，参与 RA 中的软骨破坏。
