Morphogenesis and growth of the ventricular wall in development and disease

摘要 先天性心脏病是最常见的出生缺陷。尽管很普遍，但 大多数CHD的潜在分子病因学尚不清楚。本计划的中心主题是项目赠款 应用是阐明调控脑室生长和形态发生的机制。 发展。我们的目标是更好地理解表观遗传、转录和细胞信号 心脏祖细胞和胚胎心肌细胞内的调节影响心脏规范， 分化和心室形态发生。四个互动性和互补性很强的项目是 建议。项目1将研究早期CPC中导致CHD发生的分子机制。 这些研究建立在斯蒂芬妮·威尔博士实验室工作的基础上，并将检验总体假设 ZIC3 X连锁异位症患者的CHDS是由心脏祖细胞异常引起的 命运。这种机制可以解释为什么在这些患者中遇到的先心病更严重。 而不是由于侧向的改变而预期的结果。项目2将研究表观遗传机制。 调节bHLH转录因子HAND1，这对左心室、乳头肌和心脏是关键的 传导系统(CCS)形态发生。这些研究建立在安东尼·菲鲁利博士的实验室和 将检验HAND1转录的表观遗传调控引导正常心肌细胞的总体假设 图案化。其他研究将确定HAND1DNA的占位和相互作用的转录伙伴，因此 建立调控左心室、乳头肌和CCS形态发生的基因调控网络。 项目3将研究对中内胚层规范和心源性分化至关重要的表观遗传学机制。 这些研究建立在休卫年博士的实验室工作的基础上，并将检验总体假设 赖氨酸甲基转移酶SMYD4调节组蛋白修饰，这对于建立正确的 CPCS。项目4将研究一种新的平面细胞极性效应蛋白SHROOM3在发病机制中的作用 先心病的风险。这些研究建立在马修·德宾博士的实验室工作的基础上，并将检验整个假设 SHROOM3在PCP途径中的一些关键点相互作用，并且识别出罕见的CHD患者- 特定的SHROOM3变异体破坏心肌细胞内的PCP。拟议的工作将由 三个核心的参与(核心A--管理；核心B--胚胎干细胞生长和遗传 改进的模型；以及核心C-心脏生理学和成像)。归根结底，该计划中提出的研究 项目拨款申请将说明表观遗传、转录和信号机制如何发生在 心脏祖细胞和胚胎心肌细胞都建立了必要的基因调控网络 心脏形态发生。重要的是，确定这些事件的分子机制将为干预措施提供信息 旨在减轻冠心病的有害影响。

ABSTRACT Congenital heart defects (CHDs) are the most commonly encountered birth defect. Despite its prevalence, the underlying molecular etiology of most CHDs is not yet known. The central theme of this Program Project Grant application is to elucidate mechanisms that regulate growth and morphogenesis of the ventricle during development. Our objectives are to better understand how epigenetic, transcriptional, and cell signaling regulation within cardiac progenitor cells (CPCs) and embryonic cardiomyocytes impact cardiac specification, differentiation, and ventricular morphogenesis. Four highly interactive and complementary Projects are proposed. Project 1 will study the molecular mechanisms contributing to the genesis of CHDs in early CPCs. These studies build on work from Dr. Stephanie Ware’s laboratory and will test the overall hypothesis that severe CHDs encountered in patients with ZIC3 X-linked heterotaxy result from abnormalities in cardiac progenitor cell fate. Such mechanisms would explain why the spectrum of CHDs encountered in these patients is more severe than what would be anticipated as a result of altered sidedness. Project 2 will study the epigenetic mechanisms regulating the bHLH transcription factor HAND1, which is critical for left ventricular, papillary muscle, and cardiac conduction system (CCS) morphogenesis. These studies build on work from Dr. Anthony Firulli’s laboratory and will test the overall hypothesis that epigenetic regulation of HAND1 transcription directs normal cardiomyocyte patterning. Other studies will identify HAND1 DNA occupancy and interacting transcriptional partners, and thus establish the gene regulatory networks regulating left ventricle, papillary muscle, and CCS morphogenesis. Project 3 will study epigenetic mechanisms critical to mesendoderm specification and cardiogenic differentiation. These studies build on work from Dr. Weinian Shou’s laboratory and will test the overall hypothesis that the lysine methyltransferase SMYD4 regulates Histone modifications essential for establishing correct numbers of CPCs. Project 4 will study the role of a novel planar cell polarity effector protein, SHROOM3, in the pathogenesis of CHDs. These studies build on work from Dr. Matthew Durbin’s laboratory and will test the overall hypothesis that SHROOM3 interacts at a number of key points within the PCP pathway, and that identified rare CHD patient- specific SHROOM3 variants disrupt PCP within cardiomyocytes. The proposed work will be facilitated by the participation of three cores (Core A – Administration; Core B - Embryonic stem cell growth and genetically modified models; and Core C - Cardiac physiology and imaging). Ultimately, the studies proposed in this Program Project Grant application will illustrate how epigenetic, transcriptional, and signaling mechanisms occurring within both cardiac progenitors and embryonic cardiomyocytes establish the gene regulatory networks necessary for cardiac morphogenesis. Importantly, defining the molecular mechanisms of these events will inform interventions aiming to mitigate deleterious impacts of CHD.