EGR1/miR-212/FGF-21通路在运动防治非酒精性脂肪性肝病中的作用

Non-alcoholic fatty liver disease (NAFLD) , a common metabolic-related disease associated with obesity and diabetes ,has become an urgent health problem. Exercise is in the frontline for NAFLD patient management. Clarifying the molecular mechanism of exercise in protecting NAFLD in order to target the key pathway and mimic its role may help to improve the prognosis of patients who cannot tolerate exercise. MicroRNAs (miRNAs, miRs) have been reported to contribute to NAFLD, however, its role in exercise-induced protection against NAFLD is needed to be clarified. Our previous studies have found that exercise could attenuate mouse NAFLD, accompanied by the down-regulation of miR-212 . Meanwhile, overexpression of miR-212 in vitro could lead to the deposition of lipid in hepatocytes, whereas the inhibition of miR-212 had the opposite effect, which was mediated by its target gene FGF-21. In addition, it was predicted that EGR1, a zinc finger transcription factor, was a potential upstream regulator of miR-212 in liver. This project is intended to further investigate the role of miR-212 in exercise-induced protection against NAFLD and its molecular mechanism in vitro and in vivo, and thus to verity our hypothesis that EGR1 / miR-212 / FGF-21 may be a key pathway in exercise protection for NAFLD. Regulating EGR1 / miR-212 / FGF-21 pathway may improve NAFLD by mimicking the effect of exercise and become the target of NAFLD treatment. This project may provide an experimental basis for the later development of new tools for the treatment of NAFLD.

非酒精性脂肪性肝病（NAFLD）是与肥胖、2型糖尿病相关的代谢性疾病，可发展至肝衰竭及肝癌，成为亟待解决的健康问题。运动是首选治疗，阐明运动防治NAFLD分子机制以期靶向模拟干预有助于改善无法耐受运动病人的预后。微小RNA参与NAFLD，但是否参与介导运动对NAFLD的保护尚待阐明。我们前期研究显示：运动改善小鼠NAFLD伴随miR-212下调；细胞水平过表达miR-212可导致肝细胞脂质沉积，抑制miR-212具有反向作用，机制研究发现该过程由其靶基因FGF-21介导。此外预测发现锌指转录因子EGR1是肝脏中miR-212上游调控因子。本项目拟通过体内外实验研究miR-212模拟运动保护NAFLD的机制，验证“EGR1/miR-212/FGF-21通路是运动防治NAFLD调控通路”假说。调控该通路或可模拟运动改善NAFLD，成为治疗靶点，为后期研发NAFLD治疗新工具提供前期实验基础。

非酒精性脂肪性肝病（non-alcoholic fatty liver disease, NAFLD）是一类与肥胖、脂代谢异常、2型糖尿病密切相关的代谢性疾病，其病理改变以弥漫性肝细胞大泡性脂肪变性为主要特征，临床可表现为单纯性非酒精性脂肪肝、非酒精性脂肪性肝炎、非酒精性脂肪性肝纤维化及肝硬化，甚至可进展为肝癌，威胁人类健康。在我国NAFLD 已超越病毒性肝炎成为慢性肝病的首要病因，NAFL的10年肝硬化发生率为4%，伴有明显炎症和坏死的NASH，10年肝硬化发生率高达22%。积极防治NAFLD对改善人们生活质量及疾病预后有重要意义。目前改良生活方式仍是NAFLD首选防治手段，尚缺乏有效干预药物。临床研究显示运动能有效防止NAFLD的发生和发展。然而，由于相当部分病人因生活习惯或疾病不能坚持或耐受运动，导致NAFLD控制不良而进展恶化。微小RNA在NAFLD 发生中的作用正日益受到重视。运动可以通过调节微小RNA 有效改善肥胖、糖尿病及心血管等疾病，然而微小RNA 是否参与介导了运动对NAFLD 的保护作用尚不清楚。.我们通过本项目的研究发现：miR-212-3p与NAFLD 的形成相关，并受到运动的逆向调节。过表达miR-212-3p可以导致脂质的沉积，而抑制miR-212-3p可以模拟运动对NAFLD 的防治作用。针对该靶点，本课题设计了一种基于重组腺相关病毒8型的microRNA-212-3P海绵及其应用专利。通过动物实验证实靶向miR-212-3P的基因治疗可以模拟运动在NAFLD中的改善作用。随后，进一步的机制研究显示，miR-212-3p通过靶基因FGF-21 调控肝细胞脂质沉积，进而参与NAFLD 的形成，此过程受到运动的逆向调节。运动如何通过miR-212-3p发挥作用？我们发现运动通过激活EGR1 的表达，下调miR-212-3p表达，减少对FGF-21 的抑制，进而改善胰岛素抵抗、氧化应激，减轻肝脏脂肪沉积，改善NAFLD。EGR1/miR-212-3p/ FGF-21 通路的建立与证实，有可能为临床上不能坚持或耐受运动的患者改善NAFLD 提供潜在的治疗靶点，对改善患者预后具有重要的临床价值。