穿心莲内酯调控STAT3通路抑制Th17分化治疗类风湿关节炎的研究

Dysfunction of Th17 cells plays a central role in in the pathogenesis of rheumatoid arthritis (RA). JAK/STAT3 signaling and activating retinoic acid receptor-related orphan nuclear receptor (RORγt) were crucial for Th17 differentiation. Our previous study in RA patients found that pretreatment with andrographolide significantly decreased the proportion of Th17 cells, and reduced the production of IL-17 and the Th17 transcription factor RORγt in stimulated CD4+T cells. These results suggested that andrographolide, regulating the STAT3 pathway, might be a promising treatment for RA. The aims of the present project were as follows: (1) to assess the utility of andrographolide as an agent for the treatment of RA by inhibiting STAT3 activation and regulation of Th17 cell differentiation; and to investigate if andrographolide further inhibited the production of inflammation cytokines and chemokines; (2) to clarify if andrographolide could attenuate the incidence and severity of collagen-induced arthritis (CIA) . Our results may will help to find new targets and agents for RA treatment.

Th17细胞异常分化在类风湿性关节炎（RA）发病中起关键作用。信号转导及转录激活蛋白3（STAT3）和其激活的维甲酸相关孤核受体γt（RORγt）是Th17细胞分化的特异性转录因子。我们前期研究发现穿心莲内酯可显著降低RA患者T细胞中RORγt表达，从而抑制Th17细胞分化以及白介素-17（IL-17）分泌，推测穿心莲内酯有望作为STAT3/RORγt通路抑制剂，通过抑制Th17分化和功能对RA起治疗作用。本项目将系统验证上述推测：1、验证穿心莲内酯是否通过调控STAT3通路而影响Th17的分化和功能，进而抑制炎性因子、趋化因子释放；2、验证穿心莲内酯是否通过阻断胶原诱导关节炎（CIA）小鼠体内STAT3表达和磷酸化，抑制下游RORγt的表达，从而调节Th17细胞的活化及功能，缓解CIA小鼠关节病理学损伤。本项目旨在通过对上述机制的研究，探索穿心莲内酯作为RA新的免疫靶向治疗的可能。

Th17细胞异常分化在类风湿性关节炎（RA）发病中起关键作用，本课题运用分子生物学和现代免疫学技术，观察广东省特色中药材穿心莲的单体提取物穿心莲内酯（AD）对RA的治疗作用及其机制。研究发现，RA患者外周血中存在异常增高的Th17细胞，且IL-17、IL-22、IL-21的表达也显著升高。RA患者外周血CD4+T细胞中的STAT3通路过度活化。AD可下调小鼠脾脏CD4+T细胞中ROR-γt的mRNA水平，上调Foxp3的mRNA水平表达。在非极化及极化条件下，AD均可抑制CD4+T细胞向Thl7细胞分化，同时诱导Treg细胞生成，改善Thl7/Treg失衡状态。AD减少IL-17、IL-22、IL-21分泌的同时促进IL-10分泌。体内实验中，我们发现AD可改善小鼠胶原诱导关节炎（CIA）模型的临床症状和滑膜病理，减少IL-17的分泌，AD主要通过抑制STAT3 磷酸化进而调控Th17分化。上述研究结果提示，AD通过STAT3介导的信号通路调节Th17分化，抑制RA的发展，AD可能是治疗RA的新药物。