PEDF-MT2A信号通路在心肌梗死中抗氧化应激的作用及机制研究

Recent studies have found that the pigment epithelium derived factor (PEDF) is closely related to antioxidative stress after myocardial infarction (MI). We have previously demonstrated that metallothionein 2A (MT2A) was a specific binding molecule of PEDF on cardiomyocytes. The existence of PEDF-MT2A molecular pathways play a role of resistance to oxidative stress after MI and the mechanism in myocardial cells is not clear. Based on our previous research, the cardiac-conditional knock-out mice (PEDF-cKO and MT2A-cKO) and double cardiac-conditional knock-out mice (PEDF/MT2A-dcKO) were used, this proposal is to investigate the anti-oxidative function of PEDF-MT2A in MI and cardiomyocytes, and to determine the molecular mechanism of PEDF-MT2A signaling in mediating cardiac oxidative stress. The outcome of this proposal could be a new therapeutic strategy in future treatment of cardiac oxidative stress, and provide a novel theory and experimental basis for prevention of MI oxidative stress.

新近研究发现，色素上皮衍生因子(PEDF)与心肌梗死(MI)后抗氧化应激作用密切相关，申请者前期预实验发现抗氧化蛋白金属硫蛋白2A(MT2A)是PEDF在心肌细胞的特异性结合分子。然而，MI后心肌细胞内是否存在PEDF-MT2A分子通路发挥抗氧化应激作用及其机制尚不清楚。本项目拟在前期研究的基础上，采用心脏条件性基因敲除小鼠(PEDF-cKO和MT2A-cKO)、双基因敲除小鼠(PEDF/MT2A-dcKO)，从整体和细胞水平研究心肌低氧性损伤后PEDF-MT2A信号通路抗氧化应激的功能及其分子信号机制，其研究成果将可能成为心脏氧化应激干预的新着眼点，为临床MI后氧化应激的防治提供新的理论基础和实验依据。

心肌梗死可以导致心肌细胞发生一系列功能变化，观察到低氧状态下心肌细胞氧化应激、凋亡、自噬的变化，并阐明其三者间的协同关系。进一步通过金属硫蛋白2A（MT2A）慢病毒转染模型证明MT2A通过减弱ROS而抗氧化应激、减少caspase-3而抗凋亡、调节LC3和P62参与自噬，进而改善心肌缺血再灌注损伤。在此基础上，进一步明确氧化应激在缺血再灌注损伤中的作用，阐明MT2A对心肌细胞缺血再灌注损伤过程中抗氧化应激是通过p-p38-MAPK信号通路起作用的，明确其分子信号通路，并表明其变化可以影响心肌细胞的功能。细胞功能是一个整体，单一的病理过程变化往往在现实生活中不存在，进而对其协同作用的研究在现实生活中有很重要的意义。进一步检测MT2A对MAPKs（ERK/INK/p38）在常氧、低氧和再复氧的表达，并检测了MT2A对心肌细胞再复氧后自噬相关LC3和P62的表达变化。