Regulation of Cardiomyocyte Maturation

项目摘要/摘要 成年心肌细胞(CMS)专门用于在一年中收缩和松弛数十亿次 动物的一生。许多适应允许成年CMS履行这一角色，包括：大的，拉长的形状； 高度组织的细胞-细胞连接网络；对氧化代谢的依赖；近乎结晶的阵列 肌节.围绕质膜网络的钙释放单元的特征组织 T管内陷；细胞周期退出；成体CM特异性收缩钙的表达 操控和离子通道基因。在小鼠中，这些适应大多是在出生后的前三个月获得的 几周。对CM成熟程序的分子调控知之甚少。这种信息鸿沟 限制了刺激干细胞来源的CMS成熟的合理方法的发展。此外，它是 很可能是先天性心脏病突变或由先天性心脏病引起的异常心脏应激 畸形对心肌成熟的影响及其对先天性心肌长期表现的影响 心脏病患者。 我们的长期目标是了解管理CM成熟的监管计划。我们的 初步数据表明，GATA4和GATA6(GATA4/6)转录因子是CM的必需转录因子 成熟。此外，正向遗传筛查发现了RNA聚合酶II的一个组成部分TAF3 预启动复合体和阅读器H3K4me3的表观遗传标记，作为一种新的成熟调节因子。使用 许多独特和新颖的工具和方法，本提案将调查控制CM的机制 成熟。目标1将剖析GATA4和GATA6调节增强子活性的机制 Cm成熟。目标2将进一步描述TAF3突变体的特征，并剖析其调节机制 成熟。AIM 3将应用我们创新的体内正向遗传筛查来发现信号分子和 先天性心脏病基因是CM成熟所必需的。 胎儿CMS向成熟CMS的协调转换是最不好的之一 了解心脏发育的各个方面。成功实现该提案的目标将在以下方面提高我们的知识 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.