从CaN/NFAT信号通路探讨青藤碱抑制胶原诱导性关节炎MDSCs分化为OCs的机制

Abnormal activation of osteoclasts (OCs) is the core mechanism of bone destruction in rheumatoid arthritis (RA). The suppression of OCs differentiation and bone erosion is the one of the main objectives of treatment. Our previous research indicated that myeloid-derived suppressor cells (MDSCs) had a critical pro-inflammatory role, and could potentially differentiate into OCs. And our studies also suggested that the counts of OCs derived from MDSCs declined obviously by inhibiting calcineurin/nuclear factor of activated T cell (CaN/NFAT) signaling pathway. Additionally, it has been reported that sinomenine (SIN) could significantly restrain bone destruction, but further research is need to clarify whether SIN suppresses differentiation of MDSCs into functional OCs by inhibiting CaN/NFAT signaling pathway. In the light of the above, our project will establish collagen-induced arthritis (CIA) model, and investigate the influence of MDSCs and their OCs differentiation potential, and also reveal the mechanisms after intervention by SIN using pathology, immunology or molecular biology techniques. On the other hand, we will also establish a model of MDSCs polarization in vitro, and further confirm the mechanisms of MDSCs differentiation into OCs after intervention by SIN or CaN/NFAT signaling pathway inhibitor. In conclusion, we expect to explicit the new idea on suppression of bone destruction by SIN, and provide theoretical foundation for the drug development of RA.

破骨细胞(OCs)的异常活化是类风湿关节炎（RA）骨破坏的核心机制，抑制OCs分化，阻止骨侵蚀进程，是目前RA治疗的主要目标之一。课题组前期研究发现，髓系来源的抑制性细胞(MDSCs)在RA中具有重要的促炎作用，且具有分化为OCs的潜能；抑制CaN/NFAT信号通路能显著抑制MDSCs分化为OCs。既往的研究表明中药青藤碱（SIN）具有良好的抑制RA骨破坏作用，但SIN能否通过抑制CaN/NFAT信号通路，阻止MDSCs分化为OCs，缓解关节炎骨破坏尚有待进一步研究。本研究拟建立胶原诱导性关节炎(CIA)模型，通过病理学、免疫学和分子生物学等实验手段，探讨SIN干预对CIA MDSCs分化为OCs的作用及机制；建立MDSCs体外培养，SIN及CaN/NFAT信号通路抑制剂干预细胞模型，进一步阐明SIN干预对MDSCs分化为OCs的作用及机制，为RA骨破坏防治和新药研发提供新思路和理论依据。

髓系来源的抑制性细胞(myeloid derived suppressor cell, MDSC)在类风湿关节炎（rheumatoid arthritis, RA）中具有重要的促炎作用，但与骨破坏关系不明确。循证医学证据显示中药青藤碱（sinomenine, SIN）治疗RA具有良好的疗效，但作用机制尚未完全阐明。本研究系统综述MDSCs和SIN在RA发病中的重要作用；评价SIN制剂正清风痛宁治疗RA随机对照试验的方法学和报告学质量；运用网络药理学方法探索SIN治疗RA的潜在靶点；体内外的实验探讨SIN干预对MDSCs分化为破骨细胞(osteoclast, OC)的影响及机制。结果显示：(1)MDSCs是机体免疫系统调节免疫反应的细胞群，能对多种免疫细胞，如T淋巴细胞、B淋巴细胞、树突状细胞、巨噬细胞及OCs等发挥其免疫调节功能，参与RA发病；(2)SIN通过降低TNF-α、IL-1、IL-6、IL-17等细胞因子水平以及抑制OC分化相关信号通路，如NF-κB、NFATc1、MAPK、Ca2+、JAK/STAT等信号通路活性，从而降低骨破坏的发生；(3)SIN制剂正清风痛宁治疗RA随机对照试验的方法学和报告学质量较低，研究人员应遵循AMSTAR 2量表、PRISMA声明和GRADE系统，以期在将来设计高质量的研究；(4)成功挖掘了SIN治疗RA的潜在作用靶点和信号通路，有助于阐明SIN可能通过抑制血管生成、滑膜增生和骨破坏治疗RA的作用机制；(5)SIN可能通过抑制CaN/NFAT信号通路，抑制OCs分化，改善胶原诱导性性关节炎(collagen-induced arthritis, CIA)小鼠骨破坏；(6)CIA小鼠MDSC分化为功能性的OCs，而SIN通过抑制NF-κB信号通路抑制CIA小鼠MDSC分化为OC，缓解免疫性关节炎骨破坏的发生。总之，本研究表明CIA-MDSCs分化为功能性的OCs，参与免疫性关节炎骨破坏的作用及机制，阐明SIN抑制关节炎骨破坏新的药理作用，为临床RA防治提供新思路和新药研发提供理论依据。