Cys C/Wnt通路在高龄急性心肌梗死心肌损伤中的作用及新机制

Acute myocardial infarction (AMI) is a serious threat to the health of Chinese people. Chinese elderly population is growing rapidly. The cardiac function is injured seriously and the prognosis is poor in elderly AMI patients. It is very important to make clear the inherent mechanism of myocardial injury aggravation in elderly AMI patients. Our previous research found that the level of serum cystatin C (Cys C) increased significantly, which was associated with deterioration of heart function and was an independent risk factor of death in elderly AMI patients. Some papers indicated that Cys C causethe apoptosis of myocardial cells and myocardial injury. But the specific molecular mechanism is not clear. On the basis of previous research, the present study is planed to be done as follows: first, establish an AMI model in elderly mice and a hypoxia myocardial cells model in aging cells; then, in the whole animal model level and cell molecular level respectively, using the gene silencing and over expression method, observe the relationship between the level of Cys C expression and myocardial injury in elderly AMI models, and the impacts of Cys C/ Wnt pathway activation on cardiomyocyte apoptosis, angiogenesis and fibrosis, cardiac function and survival rate; and further investigate the regulating mechanism of Cys C on synthesis of Wnt/ beta –catenin protein in aged and aging conditions. Our project will provide a new experimental evidence and prevention target point for elderly AMI clinical treatment by investigating the new mechanism of myocardium injury in elderly AMI patients.

我国高龄人口迅速增长，高龄急性心肌梗死（AMI）患者心功能受损严重、预后差，明确高龄AMI患者心肌损伤加重机制意义重大。申请人研究发现，高龄AMI患者血清胱抑素C(Cys C)明显升高且与心功能下降相关，是高龄AMI患者死亡的独立危险因素。有研究显示，Cys C导致心肌细胞凋亡和心肌损伤加重，但具体机制不明确。本项目拟在前期研究基础上，建立高龄小鼠AMI和缺氧衰老心肌细胞模型，分别在动物整体水平和细胞分子水平，采用基因沉默和过表达方法，观察Cys C表达变化与高龄AMI心肌损伤间的关系，Cys C/Wnt通路活化对心肌细胞凋亡、血管新生和纤维化、心功能和存活率的影响，进一步探讨Cys C在高龄和衰老状态下对心肌合成Wnt/β-catenin调节作用的机制。本项目通过探索临床高龄AMI患者心肌损伤新机制，为临床治疗提供新的实验依据和防治靶点。

我国高龄人口迅速增长，高龄急性心肌梗死（AMI）患者心功能受损严重、预后差，明确高龄AMI患者心肌损伤加重机制意义重大。课题组成员以衰老心肌细胞、高龄小鼠为研究对象，在细胞分子水平、动物整体水平上，探讨Wnt/β-catenin调控Cys C信号通路在高龄AMI心肌损伤中的具体机制，并在高龄AMI人群中进行验证。首先采用衰老缺氧心肌细胞为模型，对Wnt/β-catenin/Cys C/ROS/线粒体通路中的不同因素进行高表达或抑制表达干预，观察对细胞形态、活性、凋亡等生物学功能的影响，证实了该通路中各蛋白的上下游关系，Wnt/β-catenin是该通路的上游保护蛋白，可以抑制Cys C/ROS表达，减轻线粒体损伤，降低心肌细胞凋亡。Cys C通过ROS/线粒体信号通路发挥对缺氧衰老心肌细胞的损伤作用。抑制该通路，可有效降低衰老心肌细胞凋亡。接下来采用衰老小鼠AMI模型，对Wnt/Cys C通路的在体功能进行研究，证实了Wnt/β-catenin是该通路的上游保护蛋白，可以抑制Cys C/ROS表达，减轻线粒体损伤，降低心肌细胞凋亡。抑制该通路，可有效改善高龄AMI小鼠的心脏结构和功能。首次建立和完善我国高龄AMI患者流行病学数据库。首次提出Cys C水平是评价高龄AMI预后的关键指标并明确诊断界值。Cys C与同型半胱氨酸联合应用，可进一步提高诊断及预后的敏感性。本研究结果，为高龄AMI的临床治疗提供新的实验依据和防治靶点。为建立高龄AMI的预后评价体系提供良好临床证据。