Department of Experimental Immunology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands Department of Clinical Immunology and Rheumatology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
Department of Inflammation Discovery, Hoffmann-La Roche, Inc., Nutley, New Jersey, USA.
Ann Rheum Dis. 2015 Aug;74(8):1603-11. doi: 10.1136/annrheumdis-2013-204143. Epub 2014 Apr 24.
Bruton's tyrosine kinase (Btk) is required for B lymphocyte and myeloid cell contributions to pathology in murine models of arthritis. Here, we examined the potential contributions of synovial Btk expression and activation to inflammation in rheumatoid arthritis (RA).
Btk was detected by immunohistochemistry and digital image analysis in synovial tissue from biologically naive RA (n=16) and psoriatic arthritis (PsA) (n=12) patients. Cell populations expressing Btk were identified by immunofluorescent double labelling confocal microscopy, quantitative (q-) PCR and immunoblotting. The effects of a Btk-specific inhibitor, RN486, on gene expression in human macrophages and RA synovial tissue explants (n=8) were assessed by qPCR, ELISA and single-plex assays.
Btk was expressed at equivalent levels in RA and PsA synovial tissue, restricted to B lymphocytes, monocytes, macrophages and mast cells. RN486 significantly inhibited macrophage IL-6 production induced by Fc receptor and CD40 ligation. RN486 also reduced mRNA expression of overlapping gene sets induced by IgG, CD40 ligand (CD40L) and RA synovial fluid, and significantly suppressed macrophage production of CD40L-induced IL-8, TNF, MMP-1 and MMP-10, LPS-induced MMP-1, MMP-7 and MMP-10 production, and spontaneous production of IL-6, PDGF, CXCL-9 and MMP-1 by RA synovial explants.
Btk is expressed equivalently in RA and PsA synovial tissue, primarily in macrophages. Btk activity is needed to drive macrophage activation in response to multiple agonists relevant to inflammatory arthritis, and promotes RA synovial tissue cytokine and MMP production. Pharmacological targeting of Btk may be of therapeutic benefit in the treatment of RA and other inflammatory diseases.
布鲁顿酪氨酸激酶（Btk）是 B 淋巴细胞和髓样细胞在关节炎小鼠模型中导致病理的必要条件。在这里，我们研究了滑液 Btk 表达和激活对类风湿关节炎（RA）炎症的潜在贡献。
通过免疫组织化学和数字图像分析检测来自生物学上无 RA（n=16）和银屑病关节炎（PsA）（n=12）患者的滑膜组织中的 Btk。通过免疫荧光双重标记共聚焦显微镜、定量（q-）PCR 和免疫印迹鉴定表达 Btk 的细胞群。通过 qPCR、ELISA 和单重分析评估 Btk 特异性抑制剂 RN486 对人巨噬细胞和 RA 滑膜组织外植体（n=8）中基因表达的影响。
Btk 在 RA 和 PsA 滑膜组织中的表达水平相当，局限于 B 淋巴细胞、单核细胞、巨噬细胞和肥大细胞。RN486 显著抑制 Fc 受体和 CD40 配体诱导的巨噬细胞 IL-6 产生。RN486 还降低了由 IgG、CD40 配体（CD40L）和 RA 滑液诱导的重叠基因集的 mRNA 表达，并显著抑制了巨噬细胞产生 CD40L 诱导的 IL-8、TNF、MMP-1 和 MMP-10、LPS 诱导的 MMP-1、MMP-7 和 MMP-10 产生，以及 RA 滑膜外植体自发产生的 IL-6、PDGF、CXCL-9 和 MMP-1。
Btk 在 RA 和 PsA 滑膜组织中的表达相当，主要在巨噬细胞中。Btk 活性对于驱动多种与炎症性关节炎相关的激动剂诱导的巨噬细胞激活是必要的，并促进 RA 滑膜组织细胞因子和 MMP 产生。Btk 的药物靶向可能对治疗 RA 和其他炎症性疾病具有治疗益处。
