外泌体miR-885-5p调控Wnt5a信号通路在非酒精性脂肪肝炎中的作用机制研究

Nonalcoholic steatohepatitis (NASH) with high incidence, is particularly important to study the pathophysiological process and find a noninvasive target for diagnosis and treatment. In our previous study, it was confirmed that the down-regulated wnt5a over activated canonical wnt/β-catenin signaling. It is resulted in sustained activation of hepatic stellate cells, liver fibrosis and tissue reconstruction. Based on the literature, it was found that exosomes carrying miRNAs targeting Wnt5a affected the progression of NASH. From plasma exosomes of patients with NASH and healthy control, the differentially expressed miR-885-5p was screened by sequencing. So we put forward a hypothesis that exosomal miR-885-5p was capable to be a biomarker for the diagnosis of NASH, and through regulating wnt5a/β-catenin to promote the progression. The purpose of this study was mining population data of exosomal miR-885-5p to establish the specific diagnostic value of NASH, and to elucidate the molecular mechanism of NASH. It is helpful to provide the corresponding diagnostic and therapeutic targets.

非酒精性脂肪肝炎(non-alcoholic steatohepatitis, NASH)发病率高，深入研究NASH病理生理过程，寻找无创的作为NASH诊疗的靶点尤为重要。课题组前期证实在NASH中，Wnt5a表达下调，经典Wnt/β-catenin信号过度活化，引起肝星状细胞持续性激活，促进纤维化和肝组织重建；结合文献分析发现外泌体携带miRNAs可通过靶向Wnt5a影响NASH疾病进展。课题组通过分离NASH患者和表观健康人群血浆外泌体miRNAs，高通量测序筛选出差异表达miR-885-5p。基于此提出假说：在NASH中，外泌体miR-885-5p可作为NASH诊断的生物学标志物，调控Wnt5a/β-catenin促进NASH疾病进展。本研究拟从群体数据挖掘NASH诊断的特异性生物学标志物，通过细胞实验阐明外泌体miR-885-5p调控NASH的分子机制，为寻找相应诊疗靶点提供线索。

本研究在汉族人群中发现3种血浆外泌体miRNAs（miR-148a-3p、miR-192-5p和miR-122-5p）在MAFLD患者中较健康对照组明显上调，可能是MAFLD潜在的新型诊断标志物。其中miR-148a-3p具有特异性，相较于健康对照和疾病对照，仅在MAFLD组高表达。采用Logistic回归法整合外泌体miRNAs和BMI构建诊断模型是优化MAFLD诊断的可行方法，“miRNAs +BMI模型”表现出更好的诊断效能，AUROC为 0.905（95%CI 0.847-0.963），敏感度为77.9%，特异度为95.7%。进一步动物实验结果显示MAFLD小鼠血浆外泌体miR-122-5p和miR-148a-3p表达水平相较于健康对照组升高，而在肝脏组织中表达降低，并且生化检测也观察到肝酶、血糖的升高。脂毒性肝细胞来源的外泌体miR-122-5p通过调节CS蛋白，使促炎Kupffer细胞（M1）激活在MAFLD疾病进展中发挥关键作用。尚未发现脂毒性肝细胞来源外泌体miR-148a-3p可影响Kupffer细胞极化。.课题组按照计划已完成相关课题研究，并在专业期刊上发表相关学术论文9篇，课题负责人参加国际交流1次，培养博士研究生和硕士研究生毕业各1名。