基于miR-378b-p110α-PI3K/Akt通路甲基阿魏酸改善糖脂代谢抗ALD的机制研究

Studies have found that the glucose and lipid metabolism disorder caused by ethanol inhibiting the hepatic insulin signaling pathway is the main reason for the development of alcoholic liver disease (ALD). In the pre-experiment, we were surprised to find that Methyl ferulic acid (MFA) modulated the PI3K-Akt signal pathway and some glucose-lipid metabolism-related proteins and can effectively against ALD in alcoholic-induced liver disease model. However, the underlying mechanism is not fully clear. The results of miRNA sequencing showed that MFA can downregulate the expression of miRNA-378b significantly. It has been reported in the literature that miR-378 and its homologous sequences regulate the key genes of insulin signaling and lipid metabolism in different aspects. MiR-378b can bind to p110α subunit directly, and downregulation of miRNA-378b can activate PI3K-Akt signal pathway . Therefore, MFA is most likely to be a good new potential drug for the treatment of ALD. This study intends to elucidate how MFA works on miR-378b-p110α-PI3K/Akt signal pathway and its molecular mechanisms by using L-02 cell model, NIAAA rat model and miR-378 knockout or overexpressed mouse model , combining with the miR-378b mimic and inhibitor, p110α RNAi interference and overexpression. It is very profound for clearly explaining the pathogenesis of ALD and understanding the mechanism of the effect of MFA on ALD.The study provides new ideas and new targets for the discovery and research of new anti-ALD drugs.

研究发现乙醇抑制肝脏胰岛素信号通路导致糖脂代谢紊乱是酒精性肝病(ALD)发生发展的主要原因。预实验发现甲基阿魏酸(MFA)对PI3K-Akt通路和糖脂代谢相关蛋白调控能有效抑制ALD，其机制不清楚。ALD大鼠肝组织miRNA测序显示MFA能显著下调miR-378b表达。文献报道miR-378及其同源序列在不同环节对胰岛素信号传导和脂代谢关键基因有调控作用。本实验组推测MFA抗ALD机制可能与下调miR-378b表达，调控PI3K-Akt信号通路，改善糖脂代谢有关。本项目拟采用L-02细胞模型、NIAAA大鼠模型及miR-378b敲除或过表达小鼠模型,结合miR-378bmimic和inhibitor技术，p110αRNAi干扰和过表达技术，阐明MFA调控miR-378b-p110α-PI3K/Akt信号通路抗ALD的分子机制。该研究为新型抗ALD药物的发现与研究提供了新思路和新靶点。

酒精性肝病（alcoholic liver disease ALD）的发病率在我国每年均在不断增加，已经比肩与病毒性肝炎而成为排名第二的肝脏疾病，对人民身体健康造成极大危害。ALD最初一般表现为脂肪肝，可进一步发展成酒精性肝炎、肝纤维化和肝硬化，并且可引发广泛性肝细胞坏死甚至肝功能衰竭。目前对ALD的治疗没有有效的方法。从蝉翼藤根茎中分离得到一种白色针状化合物，经结构鉴定为甲基阿魏酸（methyl ferulicacid ,MFA），化学名称为 3,4-二甲氧基-苯丙烯酸，别称咖啡酸二甲醚。.本课题利用乙醇诱导L-02细胞酒精性肝病模型和Lieber-DeCarli液体饲料加急性酒精灌胃建立酒精性肝病小鼠模型，评价甲基阿魏酸抗ALD的药效并探索了其机制。结果均显示，不同剂量的MFA能够逆转乙醇所致L-02细胞和酒精喂养小鼠肝脏中miR-378b表达的异常增加，同时提高了作为miR-378b靶点的IR、p110α的mRNA和蛋白表达水平。总之，本研究通过体内外实验证实了miR-378b调控IR和p110α转录，调节PI3K-Akt及其下游信号通路（GSK3、FoxO1、SREBP-1）信号通路，是抗ALD的关键靶点，这对人类认识ALD的发病机制提供崭新的视角，对新药发现、对预防和治疗ALD有重要价值。MFA可改善ALD脂代谢并对ALD中肝胰岛素抵抗的积极影响，并首次提出MFA的作用机制至少部分通过抑制miR-378b靶向调控IR和p110α，介导PI3K-Akt通路的激活，从而改善酒精性肝病糖脂代谢。本项目的开展对促进广西民族草药五味藤（蝉翼藤）活性成分的深入研发、为MFA用于防治ALD提供了实验依据，该研究具有重要科学意义和应用前景。