HDMCP及Hadha在非酒精性脂肪性肝炎中的作用机制及microRNA调控研究

Mitochondrial dysfunction plays a pivotal role in the pathogenesis of nonalcoholic steatohepatitis (NASH), which might be related with uncoupling protein (UCP) guided oxidative phosphorylation. Supported by National Natural Science Foundation of China (81000169), we demonstrated increased HDMCP (a novel found UCP) level in NASH. Furthermore, targeting HDMCP can alleviate inflammation degree in NASH cell model, which was found to be involved with ATP and hydrogen peroxide levels change. Nevertheless, though we successfully changed HDMCP level in NASH rat model, there is no change in inflammation degree, which suggested the existence of other regulation mechanisms in complicated in vivo environment. Therefore, we raised two hypothesis:“1, HDMCP might be regulated by miRNA;2, there might be other mitochondrial proteins with uncoupling activity that took part in the pathogenesis of NASH”. To answer this question, we plan to use our previously accumulated data in NASH proteomics and miRNA expression for further research. We plan to investigate the uncoupling activity of Hadha that belongs to mitochondrial inner protein and is similar to the sequence of known UCPs. Researches on the effect and miRNA regulation of Hadha are also carried out. As miRNA-15a was found to suppress UCP2 expression, we will further investigate its regulation on HDMCP. Other potential miRNAs-HDMCP regulation network predicted by informatics will also be investigated. With the increased prevalence of NASH in the world, our research will provide novel mechanism and therapeutic method for NASH.

线粒体功能失调在非酒精性脂肪性肝炎(NASH)发生发展中发挥重要作用，这可能与解偶联蛋白(UCP)介导的氧化磷酸化解偶联相关，但具体机制不明。我们前期在国家自然科学基金(81000169)资助下，已经阐明新型解偶联蛋白 HDMCP在NASH阶段显著增高，而在细胞模型中以其为靶点可改善NASH炎症程度，可能与调节ATP与过氧化氢水平有关。但在NASH大鼠模型中成功干扰HDMCP表达后，NASH炎症程度无显著性改变，提示在体内复杂的环境中可能存在其他调控机制。为此，本课题组提出“1，HDMCP可能受miRNA调控；2，可能存在其他具有解偶联功能的线粒体蛋白在NASH发病中起作用”这两大假说。我们拟在前期积累的NASH蛋白质组及miRNA表达谱数据的基础上，重点研究与已知UCP序列相近的线粒体内膜蛋白Hadha的解偶联功能、其在NASH发生发展中的作用机制以及上游miRNA调控。同时已知miRN

线粒体功能失调在非酒精性脂肪性肝炎(NASH)发生发展中发挥重要作用，这可能与解偶联蛋白(UCP)介导的氧化磷酸化解偶联相关，但具体作用机制及调控因子仍然不明。在本项国家自然科学基金的支持下，课题组首先发现肝脏特异性解偶联蛋白HDMCP在NASH阶段显著性升高，后通过双荧光素酶报告基因法证实miR-146是其上游调控因子。而以HDMCP干扰RNA进行干扰后，于体内及体外层面均发现NASH得到不同程度的改善（包括脂质沉积、细胞凋亡和炎症反应等），可能下游机制是影响H2O2和ATP水平。接下来，课题组阐明线粒体内膜蛋白Hadha在NASH中的变化及干扰其表达对NASH的治疗作用，但Hadha的解偶联功能因在氧电极法和膜电位测定法中的到的结果不同而需进一步验证。最后，课题组以芯片初筛结合qRT-PCR验证的方法，得到NASH特异性circRNA表达谱；并以此为基础，综合运用生物信息学方法，发现若干条在NASH发生发展中起到重要作用的circRNA-miRNA-mRNA通路，为后续NASH研究提供新思路。在NASH发病率日益增高的现状下，本课题为丰富疾病发病机制及拓展治疗方法做出了有益的尝试。我们共发表标注课题资助的SCI相关文章6篇，参加国际会议交流1次，访问国外合作者实验室1次，协助培养博士研究生2名，成功申请到自然科学基金面上项目（81770574）1项。