Department of Rheumatology and Immunology, Changhai Hospital, Second Military Medical University, 168 Changhai Road, Shanghai 200433, China.
Rheumatology (Oxford). 2014 May;53(5):802-9. doi: 10.1093/rheumatology/ket447. Epub 2014 Jan 17.
Recent studies have suggested immunomodulatory and anti-inflammatory effects of cannabinoid receptor 2 (CB2R) activation, which shows no psychoactivity. However, it is still unclear whether CB2R is expressed in fibroblast-like synoviocytes (FLS) of RA. In this study we investigated whether CB2R is expressed in FLS of RA, and whether CB2R activation modulates the function of RA-FLS.
Expression of CB2R in synovial tissue and FLS was studied by immunohistochemistry, western blotting and RT-PCR. mRNA expression levels of CB2R, IL-6 and MMPs were analysed by quantitative real-time RT-PCR. The protein concentrations of IL-6 and MMPs in culture supernatants were determined by ELISA. The protein levels of signal transducing molecules were assayed by western blotting.
Both mRNA and protein expression of CB2R were found in synovial tissue and cultured FLS with slightly higher levels in RA patients than in OA patients. In cultured RA-FLS, the expression level of CB2R was up-regulated by stimulation with IL-1β, TNF-α or lipopolysaccharide. In vitro, HU-308, a selective CB2R agonist, inhibited IL-1β-induced proliferation of RA-FLS as well as IL-1β-induced production of MMP-3, MMP-13 and IL-6 in RA-FLS in a dose-dependent manner. HU-308 also suppressed IL-1β-induced activation of extracellular signal-regulated kinase 1/2 and p38 mitogen-activated protein kinase in FLS.
In RA-FLS, proinflammatory mediators up-regulate the expression of CB2R, which negatively regulates the production of proinflammatory cytokines and MMPs. These data suggest that CB2R may be a potential therapeutic target of RA.
最近的研究表明，大麻素受体 2（CB2R）的激活具有免疫调节和抗炎作用，而不会产生精神活性。然而，CB2R 是否在类风湿关节炎（RA）的成纤维样滑膜细胞（FLS）中表达仍不清楚。本研究旨在探讨 CB2R 是否在 RA 的 FLS 中表达，以及 CB2R 的激活是否调节 RA-FLS 的功能。
通过免疫组织化学、Western blot 和 RT-PCR 研究滑膜组织和 FLS 中 CB2R 的表达。通过定量实时 RT-PCR 分析 CB2R、IL-6 和 MMPs 的 mRNA 表达水平。通过 ELISA 测定培养上清液中 IL-6 和 MMPs 的蛋白浓度。通过 Western blot 测定信号转导分子的蛋白水平。
在滑膜组织和培养的 FLS 中均发现 CB2R 的 mRNA 和蛋白表达，RA 患者的表达水平略高于 OA 患者。在培养的 RA-FLS 中，IL-1β、TNF-α 或脂多糖刺激可上调 CB2R 的表达。在体外，选择性 CB2R 激动剂 HU-308 呈剂量依赖性抑制 IL-1β 诱导的 RA-FLS 增殖以及 IL-1β 诱导的 MMP-3、MMP-13 和 IL-6 在 RA-FLS 中的产生。HU-308 还抑制了 FLS 中 IL-1β 诱导的细胞外信号调节激酶 1/2 和丝裂原活化蛋白激酶 p38 的激活。
在 RA-FLS 中，促炎介质上调 CB2R 的表达，负调节促炎细胞因子和 MMP 的产生。这些数据表明 CB2R 可能是 RA 的潜在治疗靶点。
