Division of Clinical Immunology and Rheumatology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
Am J Pathol. 2010 Dec;177(6):3010-24. doi: 10.2353/ajpath.2010.091053. Epub 2010 Oct 22.
Changes in the expression and activation status of Ras proteins are thought to contribute to the pathological phenotype of stromal fibroblast-like synoviocytes (FLS) in rheumatoid arthritis, a prototypical immune-mediated inflammatory disease. Broad inhibition of Ras and related proteins has shown protective effects in animal models of arthritis, but each of the Ras family homologues (ie, H-, K-, and N-Ras) makes distinct contributions to cellular activation. We examined the expression of each Ras protein in synovial tissue and FLS obtained from patients with rheumatoid arthritis and other forms of inflammatory arthritis. Each Ras protein was expressed in synovial tissue and cultured FLS. Each homolog was also activated following FLS stimulation with tumor necrosis factor-α or interleukin (IL)-1β. Constitutively active mutants of each Ras protein enhanced IL-1β-induced FLS matrix metalloproteinase-3 production, while only active H-Ras enhanced IL-8 production. Gene silencing demonstrated that each Ras protein contributed to IL-1β-dependent IL-6 production, while H-Ras and N-Ras supported IL-1β-dependent matrix metalloproteinase-3 and IL-8 production, respectively. The overlap in contributions of Ras homologues to FLS activation suggests that broad targeting of Ras GTPases in vivo suppresses global inflammation and joint destruction in arthritis. Consistent with this, simultaneous silencing of H-Ras, K-Ras, and N-Ras expression significantly reduces inflammation and joint destruction in murine collagen-induced arthritis, while specific targeting of N-Ras alone is less effective in providing clinical benefits.
Ras 蛋白表达和激活状态的改变被认为有助于类风湿关节炎（一种典型的免疫介导的炎症性疾病）中基质成纤维样滑膜细胞（FLS）的病理表型。Ras 和相关蛋白的广泛抑制在关节炎动物模型中显示出保护作用，但 Ras 家族的每个同源物（即 H-、K-和 N-Ras）对细胞激活都有不同的贡献。我们检查了从类风湿关节炎和其他形式的炎症性关节炎患者获得的滑膜组织和 FLS 中每种 Ras 蛋白的表达。每种 Ras 蛋白在滑膜组织和培养的 FLS 中均有表达。每种同源物在 FLS 受到肿瘤坏死因子-α或白细胞介素（IL）-1β刺激后也被激活。每种 Ras 蛋白的组成性激活突变增强了 IL-1β诱导的 FLS 基质金属蛋白酶-3 的产生，而只有活性 H-Ras 增强了 IL-8 的产生。基因沉默表明，每种 Ras 蛋白都有助于依赖于 IL-1β的 IL-6 的产生，而 H-Ras 和 N-Ras 分别支持依赖于 IL-1β的基质金属蛋白酶-3 和 IL-8 的产生。Ras 同源物对 FLS 激活的贡献重叠表明，体内 Ras GTPases 的广泛靶向抑制关节炎中的全身炎症和关节破坏。与此一致，同时沉默 H-Ras、K-Ras 和 N-Ras 的表达可显著减少小鼠胶原诱导性关节炎中的炎症和关节破坏，而单独针对 N-Ras 的特异性靶向在提供临床益处方面效果较差。
