The role N-terminal acetylation in dilated cardiomyopathy and associated arrhythmia

项目总结 心肌病和心力衰竭是世界范围内发病率和死亡率的主要原因。在……里面 除了心功能不全外，心力衰竭相关的室性心律失常还会导致猝发 死亡，几乎没有改变疾病的治疗方法。心肌传导改变，纤维化增加， 离子通道特征和遗传易感性的改变都被认为是 心力衰竭导致心律失常的风险增加，但其统一机制尚不清楚。邮寄- 心肌蛋白质的翻译修饰(PTM)已成为介导 当调节失调时，生理功能正常或导致心脏病。最近，该基因的突变 N末端乙酰基转移酶复合体A型(NatA)在先天性心脏病患者中已被发现 心脏病、心肌病和心律失常。这种蛋白质复合体使N-末端乙酰化。 调节稳定性、亚细胞定位和复合体形成的新生蛋白质，近40% 作为潜在靶点的蛋白质组。我们最近发现了一个具有新突变的大家族 在NatA的催化亚基NAA10中。男性患者QTS严重延长，复发 女性患者的心律失常、发育迟缓、学习障碍和心肌病 更易受影响的是。我们使用诱导多能干细胞建立了NAA10功能障碍的模型 来自几个受影响的男性患者的细胞(IPSCs)。分化型的电生理分析 IPSC来源的心肌细胞(IPSC-CMS)表现为动作电位时程(APD) 肌节结构的延长、异常、钙处理及相应 钠、钾电流调节失调。建立合作伙伴网络，我们 研究了NAA10功能障碍的机制，并建立了一种心脏功能障碍的动物模型。 NAA10的特异性消融。我们建议使用我们的可伸缩模型系统来研究 目前尚不清楚心脏内N-末端乙酰化作为了解的切入点的作用 心力衰竭中心律失常风险的机制。在目标1中，我们将确定如何 N-末端乙酰化调节钠和钾离子通道以及其他 靶蛋白。在目标2中，我们将使用最近开发的小鼠模型来选择性地消融Naa10 和心脏内的副链NAA12来确定N-末端的致病机制 乙酰化与心力衰竭和心律失常的发生。在目标3中，我们考察了N-末端的贡献 包括人类心力衰竭在内的获得性心脏病的乙酰化。这是变革性的 该提案将提供对N-末端鲜为人知的作用的新的机械性见解 心血管疾病中的乙酰化有可能改善心律失常风险分层和 治疗方面的发展。

PROJECT SUMMARY Cardiomyopathy and heart failure are leading causes of morbidity and mortality world-wide. In addition to ventricular dysfunction, heart-failure associated ventricular arrhythmias cause sudden death with few disease-modifying therapies. Changes in myocardial conduction, increased fibrosis, alterations of ion channel characteristics and genetic susceptibilities have all been postulated to underlie the increased risk of arrhythmia in heart failure, but no unifying mechanism is known. Post- translational modifications (PTMs) of cardiac proteins have emerged as critical factors in mediating normal physiologic function or leading to heart disease when dysregulated. Recently mutations in the N-terminal acetyltransferase complex type A (NatA) have been identified in patients with congenital heart disease, cardiomyopathy, and arrhythmia. This protein complex acetylates the N-terminus of nascent proteins regulating stability, subcellular localization, and complex formation, with nearly 40% of the proteome as potential targets. We have recently identified a large family with a novel mutation in the catalytic subunit of NatA, NAA10. Male patients have severely prolonged QTs, recurrent arrhythmias, developmental delay, learning disabilities, and cardiomyopathy, with female patients more variably affected. We created models of NAA10 dysfunction using induced pluripotent stem cells (iPSCs) derived from several affected male patients. Electrophysiologic analysis of differentiated iPSC-derived cardiomyocytes (iPSC-CMs) demonstrated action potential duration (APD) prolongation, abnormalities of sarcomeric structure, calcium handling and corresponding dysregulation of sodium and potassium currents. Establishing a network of collaborators, we investigated the mechanism of NAA10 dysfunction and developed an animal model for cardiac- specific ablation of NAA10. We propose to use our scalable model systems to investigate the currently unknown role of N-terminal acetylation within the heart as an entry point to understanding the mechanisms of arrhythmia risk in heart failure. In Aim 1, we will determine the mechanism of how N-terminal acetylation regulates sodium and potassium ion channels along with the discovery of other target proteins. In Aim 2, we will use recently developed murine models to selectively ablate Naa10 and the paralogue Naa12 within the heart to determine the causative mechanisms of N-terminal acetylation in heart failure and arrhythmogenesis. In Aim 3, we examine the contribution of N-terminal acetylation in acquired forms of heart disease including human heart failure. This transformative proposal will provide novel mechanistic insight into the poorly understood role of N-terminal acetylation in cardiovascular disease with potential for improved arrhythmia risk stratification and therapeutic development.