Nr2f1a promotes atrial maintenance and ventricular growth in the embryonic zebrafish heart

项目概要/摘要 先天性心脏病（CHD）是最常见的先天性畸形类型， 与出生缺陷相关的婴儿死亡率。CHD可以影响心脏内的许多不同结构，包括 心房和心室间隔以及流出道（OFT）。房间隔缺损（ASD）通常与 心律失常和传导缺陷，这可能同时发生，由于基因突变，这两个早期 心脏腔室的发育和窦房结（SAN）的发育，其中容纳了 心脏的起搏细胞。虽然手术干预可以纠正一些冠心病，但手术通常不能修复 相关的传导缺陷。此外，心律失常是老年人发病率和死亡率的主要原因。 成人CHD孤儿核激素受体转录因子NR 2F 2的突变 家族，与多种类型的CHD相关，最常见的是ASD，但最近心室和 OFT缺陷也有报道。NR 2F 2特异性表达于两组的心房心肌细胞（AC）中， 人类和小鼠，小鼠研究表明Nr 2f 2是心房发育和维持所必需的; 然而，这些蛋白质在AC中发挥作用的机制以及NR 2F 2突变如何导致AC中的突变， 心脏病的频谱影响心房和心室还没有得到很好的理解。我们实验室最近的工作 确定斑马鱼Nr 2f 1a是哺乳动物Nr 2f 2的功能等同物。我们使用斑马鱼的初步数据 揭示了在Nr 2f 1a缺失的情况下，AC内SAN身份的进行性异位扩张。 此外，对分离的AC的RNA-seq和ATAC-seq分析的整合表明，Nr 2f 1a抑制 核心SAN基因调控网络（GRN）通过维持AC内nkx2.5的表达。在目标1中，我们 检验Nr 2f 1a通过直接维持Nkx2.5的表达来抑制SAN身份所需的假设。 此外，我们的初步数据揭示了心室发育对Nr 2f 1a的新需求。在Aim中 2、我们将检验Nr 2f 1a细胞非自主地促进心室生长的假设。最终 拟议的研究有可能阐明以前未知的分子和遗传病因学的基础 先天性心律失常和心脏病影响心房和心室与NR 2F 2突变有关， 在人类身上。

Project Summary/Abstract Congenital heart defects (CHDs) are the most common type of congenital malformation and the leading cause of birth defect associated infant death. CHDs can affect many different structures within the heart, including the atrial and ventricular septa and outflow tract (OFT). Atrial septal defects (ASDs) are often associated with arrhythmias and conduction defects, which can occur concurrently due to mutations in genes vital for both early development of the cardiac chambers and development of the sinoatrial node (SAN), which houses the pacemaker cells of the heart. While surgical intervention can correct some CHDs, surgery often does not repair associated conduction defects. Furthermore, arrhythmias are the leading cause of morbidity and mortality in adults with CHDs. Mutations in NR2F2, a member of the orphan nuclear hormone receptor transcription factor family, have been associated with multiple types of CHDs, most commonly ASDs but recently ventricular and OFT defects have been reported as well. NR2F2 is specifically expressed in atrial cardiomyocytes (ACs) in both humans and mice, and mouse studies have shown that Nr2f2 is required for atrial development and maintenance; however, the mechanisms by which these proteins function within ACs and how mutations in NR2F2 result in a spectrum of CHDs affecting both the atria and ventricles are not well understood. Recent work from our lab has identified zebrafish Nr2f1a as the functional equivalent of mammalian Nr2f2. Our preliminary data using zebrafish has revealed that in the absence of Nr2f1a there is a progressive ectopic expansion of SAN identity within ACs. Furthermore, integration of RNA-seq and ATAC-seq analysis of isolated ACs suggests that Nr2f1a represses the core SAN gene regulatory network (GRN) by maintaining expression nkx2.5 within ACs. In Aim 1, we will test the hypothesis that Nr2f1a is required to repress SAN identity by directly maintaining expression of Nkx2.5. Additionally, our preliminary data has revealed a novel requirement for Nr2f1a in ventricular development. In Aim 2, we will test the hypothesis that Nr2f1a cell non-autonomously promotes ventricular growth. Ultimately, the proposed studies have the potential to illuminate previously unknown molecular and genetic etiology underlying congenital arrhythmias and CHDs affecting both the atria and ventricles associated with NR2F2 mutations found in humans.