RAP1调控线粒体自噬影响代谢性脂肪肝病发生发展的研究

代谢相关脂肪性肝病（MAFLD）发病率高，但致病机理及诊疗手段尚不完善。MAFLD中存在复杂的线粒体功能调节，但相关蛋白能否作为MAFLD诊疗标志物鲜有报道。前期，我们首次发现RAP1能定位于线粒体，并在MAFLD小鼠肝脏中表达量下降，且肝脏特异性Rap1敲除能显著减缓饮食诱导的肥胖，推测RAP1可作为MAFLD的精准诊疗标志物。初步机制分析发现RAP1敲降后线粒体自噬增强，且与Parkin介导的线粒体自噬调节因子ANT2存在相互作用，我们推测RAP1可能经由ANT2促进Parkin介导的线粒体自噬，减缓MAFLD的发生发展。为验证假设，我们将利用生物化学技术在体内外水平明确RAP1调控线粒体自噬的机制以及对MAFLD发生发展的影响；通过实验室已有人类组织标本库检测不同病程MAFLD肝脏样本的RAP1表达和线粒体自噬激活情况，为基于RAP1的MAFLD早期诊断和治疗提供理论依据。

Metabolic-associated fatty liver disease (MAFLD) is increasing in incidence worldwide, but the mechanisms and diagnosis methods are still incompletely characterized. Mitochondrion plays a complex regulation role in MAFLD, however, it is rarely reported whether mitochondrial-related proteins can be used as an accurate diagnosis marker and treatment target for MAFLD. As suggested in the preliminary work, we found for the first time that RAP1 can be localized in mitochondria, and the expression of RAP1 decreased in the liver of MAFLD mice, moreover, liver-specific knockout of RAP1 could significantly alleviate obesity induced by a high-fat diet. These results suggested that RAP1 could be used as a precise diagnosis and treatment marker for MAFLD. Preliminary mechanism analysis revealed that mitophagy was enhanced after knockdown of RAP1， and RAP1 could interacted with ANT2, a regulator involved in Parkin-mediated mitophagy. Based on these results, we speculate that RAP1 is very likely to promote mitophagy through interaction with ANT2, and slow down the occurrence and development of MAFLD. To test our idea, classical biochemical technology will be performed to clarify the mechanism of RAP1 in regulating mitophagy and the development of MAFLD in vivo and in vitro; liver samples of MAFLD patients with different pathological grades from human tissue specimen library in the laboratory will be constructed to measure the RAP1 expression and mitophagy activation, for the theoretical foundation of the early diagnosis and treatment of MAFLD based on RAP1.