The Role of HDAC3 in Cardiac Growth and Development

描述(申请人提供)：心脏发育的过程包括细胞分化和增殖，这导致了成熟心脏的形成。心脏发育异常会导致先天性心脏病，这是人类最常见的出生缺陷形式。更具体地说，影响心脏生长的通路中断可能是部分出生时左心或右心发育不良的儿童的潜在病因。了解心脏发生过程中信号通路控制增殖的心肌特异性分子机制是心脏发育和疾病的中心问题。这些途径是复杂的，在许多情况下涉及转录因子和细胞周期调节因子。共价染色质修饰在转录调节和细胞周期进程中起着关键作用，因此预计也会影响心脏的这些过程。在这些修饰中，组蛋白乙酰转移酶(HATS)的乙酰化和组蛋白脱乙酰酶(HDAC)逆转组蛋白乙酰转移酶(HATS)的乙酰化被认为是调节这些过程的关键事件。小鼠和斑马鱼模型的实验数据表明，HDAC1是HDAC家族的I类成员，在胚胎心脏的生长和发育中发挥着重要作用。然而，其他I类HDAC在心脏生长发育中的作用仍不清楚。作为主要研究人员对胚胎心肌生长和发育的兴趣的延伸，他启动了对除HDAC1以外的I类HDAC的作用的全面分析。初步研究表明，HDAC3是I类成员，在心脏生长和发育过程中都发挥着重要作用。在这项初步研究中，研究人员提议进行实验，以深入了解HDAC3在胚胎心脏生长和发育中的作用。他们将追求两个目标：特定目标1将确定HDAC3缺乏对斑马鱼胚胎心脏的影响。研究人员将通过用吗啉反义寡核苷酸破坏HDAC3的功能并将它们与HDAC3突变体进行比较来产生HDAC3缺失的斑马鱼胚胎来解决这个问题。HDAC3缺陷的胚胎将通过形态和功能分析进行评估，特别是心脏。通过使用分子标志物、细胞计数测定、细胞凋亡和增殖试验来评估分化，从而完成心脏的特征描述。特定目标2将确定由于心肌细胞内HDAC3功能丧失或由于其他支持组织中细胞功能的影响而导致的HDAC3缺陷胚胎中的心脏缺陷是什么？研究人员将通过在对照胚胎和HDAC3缺陷胚胎之间进行相互细胞移植来解决这个问题。他们还将使用选定的分子标记来解剖与心脏发育相关的心外过程，这些过程可能会在HDAC3缺陷的胚胎中受到影响。

DESCRIPTION (provided by applicant): The process of cardiac development incorporates cell differentiation and proliferation, which lead to the formation of the mature heart. Abnormalities in cardiac development result in congenital heart diseases, which is the most frequent form of birth defects in humans. More specifically, disruption of pathways affecting cardiac growth could be the underlying etiology in a subset of children born with hypoplastic left or right heart. Understanding the myocardial-specific molecular mechanisms by which signaling pathways control proliferation during cardiogenesis is a central issue in cardiac development and disease. These pathways are complex, and in many cases implicate transcription factors and cell cycle regulators. Covalent chromatin modifications play a critical role in transcriptional regulation and cell cycle progression, and therefore are expected to affect theses processes in the heart as well. Of these modifications, acetylation by histone acetyltransferases (HATs) and its reversal by histone deacetylases (HDACs) have been most studied and appreciated as a key event in regulating these processes. Experimental data from the mouse and zebrafish models suggest that HDAC1, a class I HDAC family member, plays an important role in embryonic cardiac growth and development. However, the role of other class I HDACs in cardiac growth and development remains unknown. As an extension of the principal investigator's interest in embryonic myocardial growth and development, he initiated a comprehensive analysis of the role of class I HDACs other than HDAC1. Preliminary studies suggest an important role for HDAC3, a class I member, both in cardiac growth and in development. In this pilot study, the investigators propose experiments that will offer insights into the role of HDAC3 in embryonic cardiac growth and development. They will pursue two aims: Specific Aim 1 will determine the effect of hdac3 deficiency in the zebrafish embryonic heart. The investigators will address this question by generating hdac3-deficient zebrafish embryos by disrupting hdac3 function with morpholino antisense oligonucleotides and comparing them with hdac3 mutants. The hdac3 deficient embryos will be evaluated by morphological and functional analysis with particular emphasis on the heart. Heart characterization will be completed by assessment of differentiation by the use of molecular markers, cell count determination, apoptosis, and proliferation assays. Specific Aim 2 will determine what are the cardiac defects in the hdac3 deficient embryos due to the loss of hdac3 function within cardiomyocytes or due to effects upon cellular functions in other support tissues? The investigators will address this question by reciprocal cell transplantations between control and hdac3-deficient embryos. They will also use selected molecular markers to dissect extracardiac processes relevant to cardiac development that are potentially affected in the hdac3 deficient embryos.