降脂颗粒调节Th17/Treg免疫平衡治疗非酒精性脂肪性肝炎的分子机制

Nonalcoholic steatohepatitis (NASH) is the leading cause of liver diseases and associated mortality. Traditional Chinese medicine is a promising strategy in treating NASH but the mechanisms are not clear. We developed formula called Jiangzhikeli（JZKL）to treat fatty liver disease, and which has confirmed to be safe and effective in clinical trial stage II. Animal experiments have realized that JZKL inhibited the activation of NLRP3 inflammasome, effectively improved lipotoxicity related liver injury in MCD diet induced NASH mice. Notably, it increased the expression of FoxP3 in peripheral blood and liver tissues, promoted the differentiation of regulatory T cells and inhibited the expression of Th17 cells and the secreted cytokines. Thus, we propose the hypothesis that JZKL might treat NASH through regulating Th17/Treg immunologic balance. We aim to explore the interchange of Th17/Treg in the development of NASH, clarify the regulation of JZKL on the Th17/Treg immunologic balance in promoting cell differentiation and immune-regulation function of Treg in peripheral blood from NASH patients and liver tissues of NASH animals. We hope that the results will be of great value both in promoting the application of traditional Chinese medicine in NASH prevention and treatment and in recognizing the regulation of acquired immunity in NASH.

非酒精性脂肪性肝炎(NASH)是导致肝脏病变进展和肝病相关死亡率增加的首要因素，中医药治疗NASH具有明显效果但作用机制尚不明确。课题组研制的新药降脂颗粒经II期临床试验证实对脂肪肝治疗安全有效；机制研究发现降脂颗粒在抑制NLRP3炎症小体活化、有效改善MCD饮食诱导NASH小鼠脂毒性肝损伤的同时，上调了外周血和肝脏组织中Foxp3的表达，增加了Treg的比例，同时抑制Th17辅助细胞及其细胞因子的表达。在此基础上，我们提出“降脂颗粒调节Th17/Treg免疫平衡治疗NASH”的科学假说。本项目拟通过临床和实验研究，探索Th17/Treg交互作用在NASH发展进程中的变化规律，明确降脂颗粒对于Th17/Treg免疫平衡的调控及促进Treg在NASH外周血和肝组织中的细胞分化与免疫调节功能的分子机制。预期研究结果对促进中医药防治NASH的应用及获得性免疫在NASH中的调控机制均具有重要意义。

非酒精性脂肪性肝炎(NASH)是导致脂肪肝疾病慢性化和复杂化的拐点，也是导致终末期进展的重要危险因素。课题组自行研制的降脂颗粒前期研究证实对NAFLD治疗安全有效，但对NASH治疗效果尚未开展深入。本研究临床部分共招募符合纳排标准的NASH受试者32人及健康对照组32人。采用单臂前后对照实验，证实降脂颗粒可有效改善NASH患者HOMA-IR指数及血清ALT，AST水平；并采用流式细胞术对外周血Treg细胞比例进行检测，与健康受试者比较NASH患者Treg比例显著降低，降脂颗粒可显著升高NASH受试者外周血Treg/CD4+T细胞比例，并且下调Th17细胞分泌IL17A的水平。初步证明Th17/Treg免疫平衡可以作为NASH治疗新的靶点，但仍需进一步扩大样本量，对Th17/Treg免疫平衡与血清肝功能改善、脂肪因子和细胞因子的相关性做进一步分析。采用MCD饮食诱导NASH小鼠模型，验证降脂颗粒对NASH的改善作用。结果提示，降脂颗粒干预可显著改善NASH小鼠的肝损伤、对肝脏病理也有明显改善作用。流式细胞术结合免疫组化对NASH小鼠体内Treg、Th17细胞分布进行检测，证实药物对Th17/Treg免疫平衡的调节作用主要是通过抑制肝脏SOCS2介导的IL6/STAT3信号通路，抑制Naive T细胞向Th17细胞的分化，降低IL17A促炎因子的分泌，从而抑制下游NF-κB信号通路的活化，改善肝脏的炎症免疫微环境。因此，本研究认为，Th17/Treg可以作为NASH的治疗靶点，降脂颗粒可以通过调控Th17/Treg免疫平衡改善NASH肝脏炎症免疫微环境。