A zebrafish fetal alcohol spectrum disorder model of congenital heart defects

描述(由申请人提供)：胎儿酒精谱系障碍(FASD)出生缺陷包括心房、室、房室间隔和圆锥干缺陷。这项工作的长期目标是阐明乙醇引起的心脏缺陷，特别是间隔缺陷的机制，以及叶酸对这些缺陷的保护作用。心脏组织起源于不同的祖细胞群体：第一心域(FHF)和第二心域(SHF)。FHF血统对两个房间都有贡献。SHF前体细胞对大部分心肌和流出道(OFT)有贡献。干扰这些祖细胞群体中的任何一个都可能导致心腔和瓣膜的缺陷。通过对不同信号分子的调控，这些祖细胞起源于胚胎中胚层的不同位置。特定的心脏转录因子和染色质重塑复合体BAF之间的相互作用通过调节心脏基因的表达来控制心脏的发育。心脏调节网络在从斑马鱼到人类的脊椎动物物种中都是保守的。初步研究表明，在不同的心源性事件中，斑马鱼胚胎暴露在乙醇中会扰乱心脏规格、心脏腔和瓣膜发育的形态发生。补充叶酸(FA)可以挽救乙醇引起的发育缺陷，包括瓣膜发育缺陷。在酒精对FASD患者心脏调节网络、祖细胞群体和瓣膜形态发生机制的影响方面，我们的知识存在显著差距。我们的总体假设是，乙醇诱导心脏转录因子和BAF染色质重塑复合体成分的表达波动，改变FHF和SHF祖细胞对心脏的贡献，导致心腔和瓣膜发育缺陷，而影响表观遗传过程的叶酸将恢复更正常的基因表达水平平衡，恢复更正常的心脏生成。我们的实验计划是在我们的斑马鱼FASD模型中剖析导致心脏缺陷的细胞和分子机制，具体涉及PA-12-232中描述的优先事项：干细胞和酒精诱导的组织损伤，目标是“胎儿酒精综合征”、“心血管疾病”和“改善酒精研究的动物模型”，特别是酒精对特定干细胞/祖细胞的影响。我们为这一项目提出了以下具体目标。具体目的1.检测乙醇对心肌祖细胞的调节作用，确定FHF和SHF来源的细胞在乙醇诱导的心脏缺陷中的作用。特定目的2.乙醇所致房室管和瓣膜发育缺陷的分子和细胞特征。拟议的研究将有助于确定酒精敏感的形态发生机制，这些机制可能导致FASD患者的心脏缺陷。该项目将剖析乙醇敏感的细胞和分子心脏发生机制，为先天性心脏病的发生和FA的保护作用提供洞察力。

DESCRIPTION (provided by applicant): Fetal alcohol spectrum disorder (FASD) birth defects include cardiac atrial, ventricular, atrioventricular septal defects, and conotruncal defects. The long-term goal of this work is to elucidate the mechanisms of ethanol induced cardiac defects, particularly septal defects, and folic acid protection of these defects. Cardiac tissues are derive from distinct progenitor populations: first heart field (FHF) and second heart field (SHF). FHF lineage contributes to both chambers. SHF progenitors contribute to most of the myocardium and outflow tract (OFT). Interfering with any of these progenitor populations could cause defects in chambers and valves. These progenitors originate in different locations from the embryonic mesoderm by controlled regulation of different signaling molecules. Interaction between specific cardiac transcription factors and chromatin remodeling complex BAF controls heart development by regulating cardiac gene expression. Cardiac regulatory networks are conserved across vertebrate species, from zebrafish to human. Initial studies showed that zebrafish embryos exposed to ethanol during distinct cardiogenic events disrupt cardiac specification, chamber and valve development morphogenesis. Folic acid (FA) supplementation rescued ethanol induced developmental defects, including valve development defects. There is a significant gap in our knowledge of ethanol effects on cardiac regulatory networks, progenitor populations and valve morphogenesis mechanisms in FASD patients. Our overall hypothesis is that ethanol induces fluctuation in expression of cardiac transcription factors and BAF chromatin remodeling complex components, alters FHF and SHF progenitor contributions to the heart causing chamber and valve development defects, and folic acid, which affects epigenetic processes, will restore a more normal balance of gene expression levels, restoring more normal cardiogenesis. Our experimental plan to dissect the cellular and molecular mechanisms underlying cardiac defects in our zebrafish model of FASD specifically addresses priorities described in PA-12-232: Stem Cells and Alcohol-induced Tissue Injuries, which targets 'fetal alcohol syndrome', 'cardiovascular disease' and 'improving animal models for alcohol research', particularly alcohol effects on specific stem/progenitor cells. We propose the following specific aims for this project. Specific Aim 1. Examine ethanol effects on regulators of myocardial progenitors and determine the contribution of FHF and SHF derived cells to ethanol induced cardiac defects. Specific Aim 2. Molecular and cellular characterization of ethanol induced atrioventricular canal and valve development defects. Proposed studies will help identify ethanol sensitive morphogenesis mechanisms that may contribute to heart defects in FASD patients. This project will dissect ethanol sensitive cellular and molecular cardiogenesis mechanisms, providing insight into congenital heart defect genesis and FA's protective role.