肠道VDR/MLCK/MLC信号通路在非酒精性脂肪性肝炎中的作用及降脂颗粒调控的机制研究

Non-alcoholic steatohepatitis (NASH) attracted widespread attention as the progressed stage of NAFLD, impaired intestinal mucosal barrier function is considered to play a key role in the progression of NAFLD to NASH. Our group had developed a herb formula named Jiangzhi granule in treating NAFLD, which was confirmed to be effective and safe, in previous research, we found that Jiangzhi granule could improve intestinal mucosal barrier function and gut derived endotoxemia, increase the expression of intestine vitamin D receptor in NASH model, combined with intestinal VDR pathway is a new therapeutic target for NASH, we propose the hypothesis that Jiangzhi granule may regulate intestinal VDR/MLCK/MLC pathway to improve the intestinal mucosa barrier function of NASH. In order to test this hypothesis, we intends to adopt the HF-VDD induced NASH mice model,by setting up VDR agonist group, observe the effect of Jiangzhi granule, and further investigate the influence of Jiangzhi granule on intestinal mucosal barrier function and VDR pathway; in LPS-Caco-2 cell model, employing VDR inhibitor and agonist to discuss the regulation effect of Jiangzhi granule on this pathway from two aspects. This project are expected to have important foundation and application value for the promotion of Traditional Chinese medicine in preventing and treating NASH.

非酒精性脂肪性肝炎(NSAH)作为NAFLD的进展阶段受到广泛关注，肠黏膜屏障功能受损被认为是NAFLD进展为NASH的关键环节。课题组研制的降脂颗粒经临床及实验研究证实对NAFLD安全有效，前期研究发现降脂颗粒能改善NASH小鼠的肠黏膜屏障功能和肠源性内毒素血症，上调肠道维生素D受体(VDR)的表达，结合肠道VDR通路是NASH治疗靶点的新认识，我们提出“降脂颗粒调控肠道VDR/MLCK/MLC信号通路改善NASH肠黏膜屏障功能”的假说。为验证该假说，本课题拟采用高脂联合维生素D缺乏饮食诱导的NASH小鼠模型，设立VDR激动剂对照评价降脂颗粒的效应，及对肠黏膜屏障和VDR通路的影响；体外应用LPS-Caco-2细胞模型，通过siRNA抑制VDR表达或维生素D过表达VDR，从正反两方面探讨降脂颗粒对这一通路相关分子的调节作用。预期研究结果对促进中医药防治NASH有重要的基础及应用价值。

非酒精性脂肪性肝炎（NASH）引起的肝脏和代谢危害日趋严重，但治疗手段有限。中医药治疗NASH效果显著，但作用机制尚不明确。肠黏膜屏障功能受损被 认为是NAFLD进展为NASH的关键环节。课题组研制的降脂颗粒经临床及实验研究证实对NAFLD安全有效，前期研究发现降脂颗粒能改善NASH小鼠的肠黏膜屏障功能和肠源性内毒素血症，上调肠道维生素D受体(VDR)的表达，结合肠道VDR通路是NASH治疗靶点的新认识，我们聚焦降脂颗粒调控肠道VDR/MLCK/MLC信号通路改善NASH肠黏膜屏障功能。我们应用维生素D缺乏饮食诱导小鼠NASH模型，研究了VDR状态以及VDR/MLCK/MLC信号通路改变对NASH病理进程的影响，证实了VDR低表达促进NASH进程的效应；在高脂联合维生素D缺乏饮食诱导的NASH小鼠中验证了降脂颗粒的药理效应，明确了降脂颗粒上调VDR表达以及抑制MLCK/MLC通路的作用不依赖于维生素D的水平。VDR是胆汁酸受体，我们进而通过分析粪便胆汁酸谱发现降脂颗粒上调次级胆汁酸的比例，活化VDR/MLCK/MLC信号通路改善肠道紧密连接的作用机制。通过体外细胞实验，明确了VDR活化可对抗炎症，而shRNA敲低VDR可抵消降脂颗粒有效成分的抗炎效应，此外，VDR活化可促进肠细胞紧密连接的表达，改善肠道环境。我们的研究从胆汁酸谱的改变证实了降脂颗粒内源性活化VDR改善NASH，研究结果对促进中医药防治NASH有重要的基础及应用价值。