Nav1.5的O-GlcNAc修饰及其在糖尿病心肌病所致心律失常中的作用及机制研究

Diabetes is a dangerous etiological factor of cardiovascular disease. Myocardial diastolic dysfunction as an early manifestation of diabetic cardiomyopathy (DCM), myocardial systolic dysfunction as an late manifestation of DCM. DCM eventually caused a variety of arrhythmias, heart failure, and even cardiac sudden death. The exact mechanism of DCM inducing arrhythmias has not been illuminated, and majority considered that it was correlated with the ion channel function and expression abnormalities of in ion homeostasis. This topic used neonatal rat cardiac cells, cultured primary cell with high glucose medium, and simulated diabetes cell model in vitro. In preliminary experiments, we observed that the level of O-GlcNAc modification of the total protein in cardiomyocytes after high glucose processing was increased, while the expression of Nav1.5 was increased. Our study speculated that in diabetes patients, the elevated levels of O-GlcNAc modification of myocardial tissue Nav1.5 sodium channel protein can induce cardiac electrophysiological disorder, which may be a new mechanism of DCM inducing arrhythmia. To confirm this hypothesis, we intend to build diabetes arrhythmia model, we revealed the relationship between O-GlcNAc modificatory Nav1.5 with DCM induced arrhythmias which elucidate the mechanism of exogenous anti-O-GlcNAc glucose treatment protecting DCM.

糖尿病是心血管疾病发生的重要危险因素。糖尿病性心肌病（DCM）是发生于糖尿病患者的心肌病，可引起心律失常，甚至猝死。蛋白质的氧连-N-乙酰葡萄糖胺（O-GlcNAc）修饰，被发现可以参与心律失常的发病过程。DCM致心律失常多认为与离子通道功能及表达异常有关，具体机制尚未阐明。预实验结果显示，高糖处理的心肌细胞钠离子通道蛋白Nav1.5表达增加，并且Nav1.5的O-GlcNAc修饰水平升高。故假设心肌细胞Nav1.5的O-GlcNAc修饰水平升高可诱导心电生理紊乱，导致心律失常。本课题拟用高糖诱导的心肌细胞、糖尿病大鼠和db/db鼠构建心律失常模型，观察Nav1.5的O-GlcNAc修饰水平的变化及机制，检测Nav1.5 O-GlcNAc修饰水平改变后离子通道功能的变化，以探讨Nav1.5的O-GlcNAc修饰在糖尿病心肌病所致心律失常中的作用及机制，为治疗DCM致心律失常提供实验依据。

研究内容按照原计划进行并顺利完成，首次揭示糖尿病O-GlcNAc调控钠离子通道（Nav1.5）在心律失常中的作用及其机制。发现：1、在细胞水平和动物水平，采用Western blot、免疫共沉淀、激光共聚焦、膜片钳等分子生物学方法，探讨了Nav1.5的O-GlcNAc修饰在糖尿病致心律失常中的作用及其机制（Yu P. et al. Int J Cardiology，2018，影响因子4.034）；2、糖基化研究成果，受大会特邀演讲1次，2017年8月13日在中国心脏大会(CHC2017)心血管疾病精准医学与转化论坛发言：O-GlcNAc糖基化修饰Nav1.5蛋白参与糖尿病心肌损伤所致心律失常；3、培养博士生3名，硕士生3名。博士研究生余鹏于2017年在韩国举行的亚太心律失常会议上进行口头交流，题目：New Mechanism Contributing to Diabetic Cardiomyopathy Induced Arrhythmia: O-GlcNAcylation of Cardiac Sodium Channel Nav1.5 protein, 9ST Asia-Pacific Heart Rhythm SocietyScientific Session,APHRS2016，地点：Korea Seoul，时间13 October 2016.