CX3CL1 通过 CX3CR1、c-Raf、MEK、ERK 和 NF-κB 信号通路促进骨关节炎滑膜成纤维细胞中 MMP-3 的产生。
CX3CL1 promotes MMP-3 production via the CX3CR1, c-Raf, MEK, ERK, and NF-κB signaling pathway in osteoarthritis synovial fibroblasts.
机构信息
Department of Orthopedic Surgery, Shin Kong Wu Ho-Su Memorial Hospital, No. 95, Wen Chang Road, Taipei, 111, Taiwan.
Department of Orthopedic Surgery, National Taiwan University Hospital, No. 1, Jen-Ai Road, Taipei, 100, Taiwan.
出版信息
Arthritis Res Ther. 2017 Dec 21;19(1):282. doi: 10.1186/s13075-017-1487-6.
BACKGROUND
Osteoarthritis (OA) is a degenerative joint disease that affects the cartilage, synovium, and subchondral bone and is the leading cause of disability in older populations. Specific diagnostic biomarkers are lacking; hence, treatment options for OA are limited. Synovial inflammation is very common in OA joints and has been associated with both OA's symptoms and pathogenesis. Confirming the role of the synovium in OA pathogenesis is a promising strategy for mitigating the symptoms and progression of OA. CX3CL1 is the only member of the CX3C class of chemokines that combines the properties of chemoattractants and adhesion molecules. CX3CL1 levels in the synovium and serum were both discovered to be positively associated with OA pathogenesis. CX3CL1 and its receptor CX3CR1 belong to a family of G protein-coupled receptors. Matrix metalloproteinases (MMPs), which are responsible for matrix degradation, play a crucial role in OA progression. The relationship between CX3CL1 and MMPs in the pathophysiology of OA is still unclear.
METHODS
CX3CL1-induced MMP-3 production was assessed with quantitative real-time PCR and ELISA. The mechanisms of action of CX3CL1 in different signaling pathways were studied using western blot analysis, quantitative real-time PCR and ELISA. Neutralization antibodies of integrin were achieved to block the CX3CR1 signaling pathway. Luciferase assays were used to study NF-κB promoter activity.
RESULTS
We investigated the signaling pathway involved in CX3CL1-induced MMP-3 production in osteoarthritis synovial fibroblasts (OASFs). CX3CL1 was found to induce MMP-3 production in a concentration-dependent and time-dependent manner. Using pharmacological inhibitors and CX3CR1 small interfering RNA to block CX3CR1 revealed that the CX3CR1 receptor was involved in the CX3CL1-mediated upregulation of MMP-3. CX3CL1-mediated MMP-3 production was attenuated by c-Raf inhibitors (GW5074) and MEK/ERK inhibitors (PD98059 and U0126). The OASFs were stimulated using CX3CL1-activated p65 phosphorylation.
CONCLUSIONS
Our results demonstrate that CX3CL1 activates c-Raf, MEK, ERK, and NF-κB on the MMP-3 promoter through CX3CR1, thus contributing to cartilage destruction during OA.
背景
骨关节炎（OA）是一种退行性关节疾病，影响软骨、滑膜和软骨下骨，是老年人群致残的主要原因。目前缺乏特定的诊断生物标志物，因此 OA 的治疗选择有限。OA 关节中滑膜炎症非常常见，与 OA 的症状和发病机制都有关联。确认滑膜在 OA 发病机制中的作用是减轻 OA 症状和进展的一种很有前途的策略。CX3CL1 是 CX3C 类趋化因子家族中唯一的一种趋化因子，兼具趋化因子和黏附分子的特性。研究发现，滑膜和血清中的 CX3CL1 水平与 OA 的发病机制呈正相关。CX3CL1 和其受体 CX3CR1 都属于 G 蛋白偶联受体家族。基质金属蛋白酶（MMPs）负责基质降解，在 OA 进展中发挥关键作用。CX3CL1 与 MMPs 在 OA 病理生理学中的关系尚不清楚。
方法
通过定量实时 PCR 和 ELISA 评估 CX3CL1 诱导的 MMP-3 产生。通过 Western blot 分析、定量实时 PCR 和 ELISA 研究 CX3CL1 在不同信号通路中的作用机制。采用整合素中和抗体阻断 CX3CR1 信号通路。采用荧光素酶检测法研究 NF-κB 启动子活性。
结果
我们研究了 CX3CL1 诱导 OA 滑膜成纤维细胞（OASFs）中 MMP-3 产生的信号通路。结果发现，CX3CL1 呈浓度和时间依赖性诱导 MMP-3 产生。使用药理学抑制剂和 CX3CR1 小干扰 RNA 阻断 CX3CR1 表明，CX3CR1 受体参与了 CX3CL1 介导的 MMP-3 上调。c-Raf 抑制剂（GW5074）和 MEK/ERK 抑制剂（PD98059 和 U0126）可减弱 CX3CL1 介导的 MMP-3 产生。CX3CL1 激活 p65 磷酸化可刺激 OASFs。
结论
我们的研究结果表明，CX3CL1 通过 CX3CR1 激活 MMP-3 启动子上的 c-Raf、MEK、ERK 和 NF-κB，从而在 OA 过程中导致软骨破坏。
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