PFKM表达和乙酰化修饰调控心肌糖酵解能量代谢对房颤的影响及机制研究

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, yet molecular mechanisms of AF incidence and development remain largely unknown. In the preliminary study, we found that 517 differential expressed proteins including PFKM (phosphofructokinase, muscle type), the rate-limiting enzyme of glycolysis process, were differently expressed in atrial tissue of AF patients, and the acetylation level of PFKM was also higher in those patients. It has been identified that acetylation of proteins was the critical factor of regulating cellular biological activity, and could be effected by phosphorylation. Thus, we suppose that PFKM would be regulated by acetylation, and would regulate myocardial energy metabolism of glycolysis through the modification of expression and acetylation, and then influence AF incidence and persistence. Phosphorylation may effects the expression level of acetylation of PFKM. In this project, we will construct wild-type and mutated PFKM over-expression viruses to investigate their effects on glycolysis, energy metabolism and AF incidence and persistence. Moreover, the acetylation sites of PFKM and the effects of phosphorylation on PFKM acetylation will be defined on canine model and primary cardiac myocyte. This project is likely to illustrate the influence of PFKM expression and acetylation modification on regulating energy metabolism during AF, which may contribute to new theoretical basis and therapeutic targets for AF prevention and treatment.

心房颤动（房颤）是临床上最常见的持续性心律失常，其发病机制未完全阐明；我们前期研究发现肌肉型磷酸果糖激酶（PFKM）（糖酵解限速酶）等517个与心肌能量代谢相关的蛋白质在房颤患者心肌中差异表达，且PFKM乙酰化水平显著上调。已知乙酰化修饰是细胞内调控蛋白质活性的关键因素，而磷酸化修饰能影响蛋白质乙酰化水平。据此我们提出假说：PFKM受乙酰化修饰调控，通过差异表达调节心肌糖酵解代谢途径影响房颤发生发展；磷酸化修饰则调控PFKM乙酰化水平影响PFKM表达。本研究拟构建PFKM野生型/乙酰化位点突变型病毒，在犬房颤和原代心肌细胞模型上：①研究PFKM的表达及乙酰化修饰对能量代谢的影响，②明确房颤时PFKM乙酰化调节位点及磷酸化修饰对其乙酰化水平的影响，以期阐明PFKM及其乙酰化修饰调控房颤患者心肌能量代谢受损的机制，为房颤的防治提供新的理论依据和靶点。

研究背景：本课题组在前期研究发现与窦律患者相比，房颤患者心耳蛋白质组学表达存在差异，但其机制不明。.主要研究内容：通过建立犬急性房颤模型，研究PFKM在房颤中的作用，以及二甲双胍与迷走神经刺激对房颤时PFKM及房颤易感性的影响；建立犬慢性房颤模型，分析慢性房颤模型心房肌代谢底物的变化情况，以及糖脂代谢关键酶的改变；扩大临床房颤患者心耳标本，测定乙酰化及琥珀酰化蛋白质组，分析房颤相关翻译后修饰蛋白质组学差异与关联。 .重要结果/关键数据：研究发现二甲双胍通过AMPK/PFK-2/PFK-1通路调控急性房颤心肌糖酵解，减少房颤易感性；慢性房颤时心肌糖脂代谢底物和相关代谢酶发生改变，提示心肌能量代谢重构；房颤患者的心房组织蛋白质组学和翻译后修饰组学结果提示乙酰化和琥珀酰化修饰存在相互作用，与房颤心肌能量代谢密切相关。.科学意义：本课题发现能量代谢重构在房颤发生发展过程中的重要作用以及乙酰化和琥珀酰化翻译后修饰相互作用对心肌能量代谢有重要影响，为房颤的防治提供新的理论依据和靶点。