Choe Jung-Yoon, Park Ki-Yeun, Park Sung-Hoon, Lee Sang-Il, Kim Seong-Kyu
Arthritis Res Ther. 2013 Feb 13;15(1):R26. doi: 10.1186/ar4162.
This study investigated whether the calcineurin inhibitor, tacrolimus, suppresses receptor activator of NF-κB ligand (RANKL) expression in fibroblast-like synoviocytes (FLS) through regulation of IL-6/Janus activated kinase (JAK2)/signal transducer and activator of transcription-3 (STAT3) and suppressor of cytokine signaling (SOCS3) signaling.
The expression of RANKL, JAK2, STAT3, and SOCS3 proteins was assessed by western blot analysis, real-time PCR and ELISA in IL-6 combined with soluble IL-6 receptor (sIL-6R)-stimulated rheumatoid arthritis (RA)-FLS with or without tacrolimus treatment. The effects of tacrolimus on synovial inflammation and bone erosion were assessed using mice with arthritis induced by K/BxN serum. Immunofluorescent staining was performed to identify the effect of tacrolimus on RANKL and SOCS3. The tartrate-resistant acid phosphatase staining assay was performed to assess the effect of tacrolimus on osteoclast differentiation.
We found that RANKL expression in RA FLS is regulated by the IL-6/sIL-6R/JAK2/STAT3/SOCS3 pathway. Inhibitory effects of tacrolimus on RANKL expression in a serum-induced arthritis mice model were identified. Tacrolimus inhibits RANKL expression in IL-6/sIL-6R-stimulated FLS by suppressing STAT3. Among negative regulators of the JAK/STAT pathway, such as CIS1, SOCS1, and SOCS3, only SOCS3 is significantly induced by tacrolimus. As compared to dexamethasone and methotrexate, tacrolimus more potently suppresses RANKL expression in FLS. By up-regulating SOCS3, tacrolimus down-regulates activation of the JAK-STAT pathway by IL-6/sIL-6R trans-signaling, thus decreasing RANKL expression in FLS.
These data suggest that tacrolimus might affect the RANKL expression in IL-6 stimulated FLS through STAT3 suppression, together with up-regulation of SOCS3.
本研究调查了钙调神经磷酸酶抑制剂他克莫司是否通过调节白细胞介素-6（IL-6）/Janus激活激酶2（JAK2）/信号转导及转录激活因子3（STAT3）和细胞因子信号转导抑制因子3（SOCS3）信号通路，抑制成纤维样滑膜细胞（FLS）中核因子κB受体激活剂配体（RANKL）的表达。
在有或无他克莫司治疗的情况下，通过蛋白质印迹分析、实时聚合酶链反应（PCR）和酶联免疫吸附测定（ELISA）评估IL-6联合可溶性IL-6受体（sIL-6R）刺激的类风湿关节炎（RA）-FLS中RANKL、JAK2、STAT3和SOCS3蛋白的表达。使用K/BxN血清诱导关节炎的小鼠评估他克莫司对滑膜炎症和骨侵蚀的影响。进行免疫荧光染色以确定他克莫司对RANKL和SOCS3的作用。进行抗酒石酸酸性磷酸酶染色试验以评估他克莫司对破骨细胞分化的影响。
我们发现RA-FLS中RANKL的表达受IL-6/sIL-6R/JAK2/STAT3/SOCS3信号通路调节。在血清诱导的关节炎小鼠模型中确定了他克莫司对RANKL表达的抑制作用。他克莫司通过抑制STAT3抑制IL-6/sIL-6R刺激的FLS中RANKL的表达。在JAK/STAT信号通路的负调节因子中，如CIS1、SOCS1和SOCS3中，只有SOCS3被他克莫司显著诱导。与地塞米松和甲氨蝶呤相比，他克莫司更有效地抑制FLS中RANKL的表达。通过上调SOCS3，他克莫司下调IL-6/sIL-6R转导信号对JAK-STAT信号通路的激活，从而降低FLS中RANKL的表达。
这些数据表明，他克莫司可能通过抑制STAT3以及上调SOCS3来影响IL-6刺激的FLS中RANKL的表达。
