Human rheumatoid synovial fibroblasts promote osteoclastogenic activity by activating RANKL via TLR-2 and TLR-4 activation
Human rheumatoid synovial fibroblasts promote osteoclastogenic activity by activating RANKL via TLR-2 and TLR-4 activation
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DOI：
10.1016/j.imlet.2007.03.004
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发表时间：
2007-05-15
影响因子：
4.4
通讯作者：
Kim, Ho-Youn
中科院分区：
文献类型：
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作者：
Kim, Kyoung-Woon;Cho, Mi-La;Kim, Ho-Youn
类风湿性关节炎(RA)患者关节中的先天免疫系统和炎性骨破坏之间的相互作用尚不清楚。本研究旨在探讨成纤维细胞样滑膜细胞(FLS)中Toll样受体(TLR)信号对RANKL表达和诱导破骨细胞活性的影响。采用逆转录聚合酶链式反应(RT-PCR)、实时荧光定量聚合酶链式反应(Real-time PCR)和免疫组织化学方法检测RANKL基因的表达水平。将单核细胞与经TLR配体刺激的RA-FLS在新鲜培养液中共同培养，然后进行抗酒石酸酸性磷酸酶(TRAP)活性染色。用实时定量聚合酶链式反应检测破骨细胞分子标志物。TLR-2和TLR-4在RA-FLS中的表达高于OA-FLS和正常皮肤成纤维细胞。TLR-2和TLR-4配体诱导RA-FLS表达RANKL。刺激RA-FLS的TLR也可在一定程度上诱导IL-1β和TNF-α的产生，但对IL-47的产生无影响。抑制TLR诱导的IL-1β的产生，部分逆转了TLR配体诱导的RANKL的上调。经TLR-2和TLR-4配体刺激并与人单核细胞共同培养的RA-FLS可诱导高水平的TRAP、RANK、组织蛋白酶K、降钙素受体和基质金属蛋白酶-9的表达，提示RA-FLS促进破骨细胞分化。结果提示，TLR信号通路通过TLR-2和TLR-4诱导RA-FLS中RANKL的表达，RANKL的表达促进RA滑膜中破骨细胞的分化。靶向TLRs可能是预防类风湿关节炎发病机制中炎症性骨破坏的一种有前景的方法。(C)2007 Elsevier B.V.保留所有权利。
The interplay between the innate immune system and inflammatory bone destruction in the joints of individuals with rheumatoid arthritis (RA) remains unclear. This study was undertaken to explore the effect of toll-like receptor (TLR) signaling in fibroblast-like synoviocytes (FLS) on the expression of RANKL and induction of osteoclastogenic activity. The levels of RANKL mRNA and protein were measured using RT-PCR, real-time PCR, and immunostaining. Monocytes were cocultured with RA -FLS that had been stimulated with TLR ligands in fresh media and subsequently stained for tartrate-resistant acid phosphatase (TRAP) activity. Osteoclast molecule markers were measured using real-time PCR. Expression of TLR-2 and TLR-4 was higher in RA-FLS than in OA-FLS and normal skin fibroblasts. TLR-2 and TLR-4 ligands induced RANKL expression in RA-FLS. TLR stimulation of RA-FLS also induced the production of IL-1 beta and TNF-alpha to a lesser extent; however, it had no effect on IL-47 production. Inhibition of TLR induced IL-1 beta production, which partially reversed the upregulation of RANKL induced by TLR ligands. RA-FLS stimulated by TLR-2 and TLR-4 ligands and cocultured with human monocytes induced high levels of expression of TRAP, RANK, cathepsin K, calcitonin receptor, and matrix metalloproteinase-9, suggesting that RA-FLS promote osteoclast differentiation. Our results suggest that the TLR signaling pathway, through TLR-2 and TLR-4, induces RANKL expression in RA-FLS and the expression of RANKL promotes the differentiation of osteoclasts in RA synovium. Targeting specific TLRs may be a promising approach to prevent inflammatory bone destruction in the pathogenesis of RA. (C) 2007 Elsevier B.V. All rights reserved.