肠-肝轴中TFF3信号通路在非酒精性脂肪性肝炎中的作用及降脂颗粒的干预

The prevalence of nonalcoholic steatohepatitis (NASH) is rapidly increasing. Based on the pathological mechanism of fatty liver disease “Spleen-Deficiency as the primary cause, Damp-Heat and Blood Stasis as the representation” in traditional Chinese medicine (TCM), the herb formula “Jiangzhi Granule” developed by our study group, has been proved effective in improving fatty liver disease in clinic or animal experiments. Metabolic dysfunction and oxidative stress of liver was commonly regarded as the major causes. However, as the function of gut-liver axis in chronic liver disease draws more attention in recent years, intestine barrier injury becomes to be one focus of NASH study. Trefoil factor 3 (TFF3) is an important agent in preventing epithelial damage and aiding repair in biliary duct and intestine. It was also found secreted in hepatocyte to promoting injury regeneration. Therefore, TFF3 may contribute to maintain the healthy gut-liver axis. Our previous study has found the dramatic difference of serum TFF3 level between NASH patient and normal human, as well as low expression of TFF3 in the liver of NASH mice and up-regulated TFF3 after the intervention of Jiangzhi Granule. According to the aforementioned reason, this project plans to investigate the change and role of TFF3 together with its relative molecules both in liver and intestine in NASH pathogenesis through studying clinic cases and in vitro / in vivo experiments. And the study on whether Jiangzhi Granule could improve NASH through regulating TFF3 will also be carried out. This project will help develop new target of diagnosis and therapy for NASH, and discover an alternative therapeutic mechanism of Jiangzhi Granule to provide more scientific basis for its widespread clinic application.

非酒精性脂肪性肝炎（NASH）发病率逐年升高，课题组基于其“脾虚为本，湿热淤血为标”病机研制的中药复方降脂颗粒在临床及动物试验中均有效改善脂肪肝。肝脏代谢失衡与氧化应激被认为是NASH主要因素，近年来随着肠-肝轴在慢性肝病中的作用受到重视，肠道屏障损伤成为NASH研究热点。三叶因子3（TFF3）有保护肠道和胆管上皮、促进上皮再生作用，肝细胞也可分泌TFF3促进损伤修复，推测在维持肠-肝轴正常功能中发挥作用。前期研究发现TFF3血清含量在NASH病人中显著升高，另外TFF3在NASH小鼠肝脏表达有所下调，而降脂颗粒干预使其上调。基于此，本项目拟通过临床病例、动物和细胞试验观察肠与肝TFF3及相关分子在NASH中的变化及作用，以期发现NASH诊疗新靶标，并研究降脂颗粒对TFF3通路的干预，阐述其基于中医药理论治疗NASH的药效机理，为其在临床应用和和推广提供科学依据。

非酒精性脂肪性肝炎（NASH）发病率逐年升高，目前仍然缺乏NASH有效诊疗方法。课题组基于其“脾虚为本，湿热淤血为标”病机研制的中药复方降脂颗粒在临床及动物试验中均有效改善脂肪性肝病。近年来肠-肝轴在NASH病理机制中的作用受到关注，三叶因子3（TFF3）有保护肠道粘膜和胆管上皮、促进上皮再生的作用，肝细胞也可分泌TFF3促进损伤修复，推测其在维持肠-肝轴正常功能中发挥作用。.. 本研究检测NASH患者血清TFF3水平，发现TFF3在NASH患者血清中含量下调，并与肝损伤、炎症、内毒素水平负相关。应用棕榈酸（PA）和/脂多糖（LPS）诱导肝细胞、胆管细胞、肠上皮细胞、巨噬细胞损伤模拟NASH模型，通过TFF3过表达或重组TFF3观察其干预作用，结果表明TFF3具有减轻PA和LPS诱导的肝细胞、胆管细胞、肠上皮细胞损伤的作用，及抑制巨噬细胞炎症反应、改善肠上皮细胞间紧密连接、改善肝细胞糖耐量的作用；在体内NASH小鼠模型肝脏和肠道组织中TFF3表达下调，促进肝脏和肠道屏障损伤；TFF3缺乏导致肠道、肝脏损伤加重。进一步探讨TFF3发挥作用的信号途径，发现TFF3可通过促进EGFR/AKT活化减轻肝脏和肠道上皮细胞凋亡、促进组织修复，另外可抑制NF-κB活化抑制炎症，通过下调糖异生改善糖耐量。应用降脂颗粒干预NASH小鼠，发现降脂颗粒上调肝组织TFF3表达，促进EGFR/AKT活化，抑制NF-κB活化，减轻炎症和损伤，敲除TFF3导致降脂颗粒对肝脏和肠道损伤的改善作用下降。肠道屏障异常导致LPS通过循环进入肝脏，促进炎症和代谢异常。因此调控TFF3表达影响肝脏、肠道屏障的病理变化及对肠-肝轴的改善是降脂颗粒治疗NASH的部分机制。.. 本项目探讨了TFF3表达及其相关的EGFR/AKT活化、NF-κB活化、糖异生途径等在NASH病理机制中的作用，可为NASH机制研究、诊疗新靶标提供思路。另外，本项目阐述了降脂颗粒基于TFF3对肝脏和肠道损伤及肠肝对话的改善治疗NASH新机制，阐释其基于“健脾活血、清热利湿”理论治疗NAFLD的科学内涵，为促进其在临床中的应用和推广提供依据。