Molecular mechanism of bone destruction by rheumatoid synovium and its treatment

破骨细胞可能参与了类风湿骨质破坏的过程。为了验证这一假设，我们建立了一个体外模型，不使用任何诱导剂，从培养的类风湿滑膜组织中提取的破骨细胞样细胞破坏骨。取自类风湿性关节炎和骨关节炎患者的滑膜组织，培养出约2 mm^3的含有滑膜衬里的组织块。对来自培养的滑膜组织的多核细胞进行了细胞化学和形态学研究，以寻找破骨细胞特异性标志物。组织块中成纤维细胞样细胞和巨噬细胞样细胞在淋巴细胞共存时增殖。培养14天后，出现具有抗酒石酸酸性磷酸酶活性的多核细胞。这些细胞表达液泡H~+-ATPase、玻璃体连接素受体和组织蛋白酶K。虽然[^&lt；125&gt；L]-鲑鱼降钙素结合率很低，但细胞中含有F-肌动蛋白的环状结构，并表现出很强的骨Res…。象牙切片上的加工活动更多。在有成纤维细胞样细胞存在的培养6个月中，巨噬细胞样细胞继续增殖并形成多核细胞。类风湿滑膜组织来源的多核细胞的骨吸收活性远高于骨性关节炎滑膜组织来源的细胞，并与类风湿关节炎的疾病活动有关。我们的培养体系在体外复制了类风湿滑膜的骨破坏过程，包括前体细胞的增殖和融合、极化、激活和骨组织吸收。为了阐明滑膜细胞向破骨细胞分化的分子机制，我们检测了RNAKL/RANK依赖或独立途径的参与。RANKL的诱骗受体Osteoprotergrin阻断RANKL/RANK依赖的信号，显著减少培养的类风湿滑膜的骨吸收。在体外骨吸收中，通过肿瘤坏死因子受体II介导的对肿瘤坏死因子α作用的阻断也减少。我们的数据提示，在体外骨破坏模型中，RANKL依赖和独立的信号都可能参与破骨细胞的形成。较少

Osteoclasts may be involved in the process of rheumatoid bone destruction. To test this hypothesis, we developed an in vitro model of bone destruction by osteoclast-like cells derived from cultured rheumatoid synovial tissue without using any inducers. Synovial tissues were obtained from rheumatoid arthritis and osteoarthritis patients and tissue pieces of about 2 mm^3 that contained synovial lining were cultured. Multinucleated cells derived from cultured synovial tissues were studied cytochemically and morphologically for osteoclast-specific markers. Fibroblast-like and macrophage-like cells from the tissue pieces proliferated in the coexistence of lymphocytes. After 14 days of culture, multinucleated cells with tartrate-resistant acid phosphatase activity appeared. These cells expressed vacuolar H^+ -ATPase, the vitronectin receptor, and cathepsin K. Although [^<125>l]-salmon calcitonin binding was very low, the cells contained ringed structures of F-actin and showed strong bone res … More orbing activity on ivory slices. Proliferation of macrophage-like cells and formation of multinucleated cells continued during 6 months of culture in the presence of fibroblast-like cells. The bone-resorbing activity of multinucleated cells derived from rheumatoid synovial tissue was much higher than that of cells from osteoarthritis synovial tissue, and was related to the disease activity of rheumatoid arthritis Our culture system reproduced in vitro the process of bone destruction by rheumatoid synovium, including the proliferation and fusion of precursor cells, polarization, activation, and bone tissue resorption. To clarify the molecular mechanism of the differentiation from synovial cells to osteoclasts, we tested the involvement of RNAKL/RANK-dependent or independent pathway. Blocking of RANKL/RANK-dependent signals by osteoprotergrin, a decoy receptor of RANKL significantly reduced bone resorption by cultured rheumatoid synovium. Blockade of TNFα action mediated through TNF-recptor II also decreased in vitrop bone resorption. Our data suggest that both RANKL-dependent and independent signals might be involved in the formation of osteoclasts in the in vitro model of bone derstruction. Less