SIRT3-p53/PGC-1α通路介导电针抑制肥胖小鼠白色脂肪细胞线粒体自噬的研究

Abnormal energy metabolism of adipocytes is an important mechanism for the pathogenesis of obesity, and it is also a target for electroacupuncture. The preliminary study of our team confirmed that electroacupuncture can effectively promote the browning of white adipocytes and accelerate their energy metabolism. The detailed mechanism needs further study. Evidence suggests that mitochondrial autophagy (Mitophagy) plays an important role in the browning of white adipocytes. It is recently discovered that intracellular energy-sensing factor Sirtulin3 can inhibit mitophagy by regulating downstream p53 and PGC-1α. Therefore, it is proposed that electroacupuncture can regulate the downstream p53/PGC-1α signal by up-regulating Sirt3 expression, thereby inhibiting mitophagy and promoting browning of white adipocytes, which may be an important mechanism for electroacupuncture to regulate fat metabolism. In order to verify the hypothesis, we plan to establish an obese animal model through high-fat diet. After electroacupuncture intervention, browning of white adipocytes, the effect of electroacupuncture on mitophagy and the relationship between Sirt3-p53/PGC-1α signaling-mediated mitophagy and acupuncture will be observed through tissue histomorphology and molecular biology methods. Our study intends to provide a theoretical basis for the treatment of obesity by improving the metabolism of white adipocytes of electroacupuncture and to provide new directions and new strategies for the clinical treatment of obesity.

脂肪细胞能量代谢异常是肥胖病发病重要机制，同时也是电针的作用靶点。项目组前期研究证实电针能有效促进白色脂肪细胞褐色化，加速其能量代谢，其详细机制有待深入研究。证据表明线粒体自噬在白色脂肪细胞褐色化中发挥重要作用，最新发现细胞内能量感受因子Sirtulin3可通过调节下游p53及PGC-1α抑制线粒体自噬。因此提出”电针可以通过上调Sirt3表达调控其下游p53/PGC-1α信号，从而抑制线粒体自噬，并促进白色脂肪细胞褐色化，是电针调节脂肪代谢的重要机制”。为验证假说，本项目拟通过高脂饮食建立肥胖动物模型并予电针干预，通过组织形态学和分子生物学方法重点观察电针促肥胖小鼠白色脂肪褐色化效应，电针调节线粒体自噬作用以及Sirt3-p53/PGC-1α信号介导的线粒体自噬与针刺减肥效应的关系。以期为电针通过改善脂肪细胞代谢治疗肥胖病提供理论基础，并为肥胖病的临床治疗提供新方向和新策略。

肥胖目前已成为人类社会面临的重要健康问题，而电针减肥因其有效性和安全性成为了有潜力的肥胖预防和治疗方法。但是，电针减肥的具体分子机制仍不明确。本课题以高脂饮食诱导的肥胖小鼠为研究对象，首先通过对肥胖参数、各组织重量、代谢产物水平以及RER指数得测定，明确了电针减肥的有效性。随后通过Western blot、qPCR、免疫荧光染色、组织学染色等技术检测方法检测了电针干预下白色脂肪褐色样标志物表达、线粒体自噬相关标志物表达以及Sirt3基因上调情况下电针对肥胖小鼠的作用以及p53/PGC-1α信号通路相关因子的表达情况，观察了电针对白色脂肪褐色化、线粒体自噬的干预效应以及关键因子Sirt3在此过程中的调控作用。实验结果表明：1）电针干预后的肥胖小鼠体重、脂肪组织体积、肥胖相关参数均明显下降，白色脂肪褐色化标志物UCP1、Cidea、PRDM16、Pgc-1α、Sirt3增加，p53下调，说明电针能够有效干预肥胖小鼠的减肥效应。且该效应与电针促进白色脂肪褐色化有关；2）肥胖小鼠在电针干预后，线粒体自噬相关标志物LC3、beclin1、parkin及PINK1下降，p62上调，表示电针对肥胖小鼠脂肪细胞线粒体自噬存在抑制作用；3）相比单纯电针干预的肥胖小鼠，Sirt3基因上调结合电针干预组减肥效果更好、白色脂肪褐色化程度更高、线粒体自噬抑制增强，且Sirt3-p53/Pgc-1α信号通路相关因子均受到显著影响。以上结果提示电针通过影响白色脂肪褐色化和调控线粒体自噬，作用于Sirt3-p53/Pgc-1α信号通路从而达到减肥效果。该研究进一步探究了电针治疗肥胖的潜在机制，为电针减肥在临床上的推广提供了一定的理论依据。