Regulation of Cardiomyocyte Maturation

项目概要/摘要 成年心肌细胞（CM）专门用于在心肌收缩过程中强制收缩和放松数十亿次。 动物的一生一些适应性改变使成年CM能够完成这一角色，包括：大而细长的形状; 高度组织化的细胞-细胞连接网络;依赖于氧化代谢; 肌节;围绕质膜网络的钙释放单位的特征性组织 称为T-小管的内陷;细胞周期退出;和成人CM特异性收缩，钙离子 处理和离子通道基因。在小鼠中，大多数这些适应是在出生后的前三个月获得的。 周关于CM成熟程序的分子调控知之甚少。这种信息鸿沟 限制了刺激干细胞衍生的CM成熟的合理方法的开发。再者是 可能是先天性心脏病基因突变或心脏应激异常引起的先天性心脏病 畸形影响CM成熟，对先天性心脏病的长期心肌性能有影响。 心脏病患者。 我们的长期目标是了解管理CM成熟的调节程序。我们 初步数据表明，GATA 4和GATA 6（GATA 4/6）转录因子是CM所必需的 成熟此外，一项正向遗传筛选发现了TAF 3，它是RNA聚合酶II的一种组分， 前起始复合物和H3 K4 me 3表观遗传标记的阅读器，作为一种新的成熟调节剂。使用 一些独特的和新颖的工具和方法，这项建议将调查机制，控制CM 成熟目的1将剖析GATA 4和GATA 6调节增强子活性的机制， CM成熟。目的2将进一步描述TAF 3突变体的特征，并剖析其调节的机制。 成熟Aim 3将应用我们创新的体内正向遗传筛选来发现信号分子， 先天性心脏病的基因是必不可少的CM成熟。 胎儿CM向其成熟对应物的协调转化是最不好的 了解心脏发育的各个方面成功实现这一建议的目标将促进我们的知识， 这是心脏发育的未开发前沿。

Project Summary/Abstract Adult cardiomyocytes (CMs) are specialized to forcefully contract and relax billions of times during an animal's lifetime. A number of adaptations allow adult CMs to fulfill this role, including: large, elongated shape; highly organized network of cell-cell junctions; reliance on oxidative metabolism; nearly crystalline array of sarcomeres; characteristic organization of calcium release units around a network of plasma membrane invaginations known as T-tubules; cell cycle exit; and expression of adult CM-specific contractile, calcium handling, and ion channel genes. In mouse, most of these adaptations are acquired in the first three postnatal weeks. Little is known about the molecular regulation of the CM maturation program. This information gap limits development of rational approaches to stimulate maturation of stem-cell derived CMs. Furthermore, it is likely that congenital heart disease mutations or abnormal cardiac stress caused by congenital heart malformations impact CM maturation, with implications for long term myocardial performance of congenital heart disease patients. Our long term goal is to understand the regulatory program that governs CM maturation. Our preliminary data show that GATA4 and GATA6 (GATA4/6) transcription factors are essential for CM maturation. In addition, a forward genetic screen uncovered TAF3, a component of the RNA Polymerase II pre-initiation complex and a reader of H3K4me3 epigenetic marks, as a novel maturation regulators. Using a number of unique and novel tools and approaches, this proposal will investigate mechanisms that control CM maturation. Aim 1 will dissect the mechanisms by which GATA4 and GATA6 regulate enhancer activity during CM maturation. Aim 2 will further characterize TAF3 mutants and dissect the mechanisms by which it regulates maturation. Aim 3 will apply our innovative in vivo forward genetic screen to discover signaling molecules and congenital heart disease genes that are essential for CM maturation. The coordinated transformation of fetal CMs to their mature counterparts is among the least well understood aspects of cardiac development. Success with this proposal's aims will advance our knowledge in this unexplored frontier of cardiac development.