Molecular Mechanisms of Atrial Development and Regeneration

项目摘要/摘要 先天性心脏病是最常见的先天性畸形。然而，分子 大多数先天性心脏病的病因仍然知之甚少。此外，即使是手术后的先天性心脏病也可能导致 到晚年导致心律失常、中风和过早死亡的并发症。为了发展小说 能够预防冠心病的疗法和针对特定心血管组织的靶向疗法，至关重要的是获得 了解指导正常心腔发育和再生的基本机制。 因此，我们实验室的长期目标是了解指导疾病发展的保守机制 脊椎动物再生过程中使用的单个心腔和心腔特有的机制。 已知的是，很少有信号需要通过特定的心房调节器来具体地指导心房的发育 再生不被理解。这项提议的具体目的是通过以下方式阐明这些机制 共线长非编码RNA(LncRNA)家族限制Nr2f转录因子的表达，并 破译Nr2f蛋白水平如何影响成人发育和心房再生过程中的心房异质性 斑马鱼。这项建议中的研究与人类健康有关，因为现在有大量的基因组分析 这表明Nr2f2的突变与CHD，特别是人类的ASD有关。而Nr2f2基因敲除 小鼠和人类干细胞的体外研究表明，心房对Nr2f1和Nr2f2都有需求 Nr2f蛋白指导心房正常发育的机制还不完全 明白了。重要的是，目前还不了解依赖于lncRNA的调节Nr2f的机制 蛋白质。我们对一种我们称为as-oca的lncRNA的分析表明，在体内它抑制了nr2f1a的翻译，即 在功能上相当于哺乳动物的Nr2f2。此外，我们发现Nr2f1a水平以前调节 胚胎心房中心房心肌细胞的未知异质性与心房再生。在目标1中， 我们将研究AS-oca抑制nr2f1a翻译的具体机制以及它的保守性。 人诱导多能干细胞中与NR2F相关的lncRNA家族之间的机制。在目标2中，我们 我将研究Nr2f1a和规范的Wnt信号在生成心房心肌细胞中的需求 先前未被识别的心房亚群的多样性和转录签名。在《目标3》中，我们将 心房再生对心外膜的需求及心房内Nr2f1a的需求 心外膜。由于Nr2f转录因子在所有脊椎动物的心房发育中发挥着保守的作用， 这些研究将极大地提高我们对转录后调控正常的机制的理解 脊椎动物的心房发育和在心房再生过程中使用的独特机制。最终，这些 研究将获得可用于改进治疗方法的知识基础，这些疗法能够预防和 改善冠心病，有效修复受伤的心脏。

Project Summary/Abstract Congenital heart defects (CHDs) are the most common congenital malformations. However, the molecular etiology underlying most CHDs remain poorly understood. Furthermore, CHDs even following surgery can lead to complications later in life that result in arrhythmias, stroke, and premature death. In order to develop novel therapies able to prevent CHDs and target therapies to specific cardiovascular tissues, it is critical to garner understanding of fundamental mechanisms directing normal cardiac chamber development and regeneration. Therefore, long-term goals of our lab are to understand conserved mechanisms that direct the development of individual cardiac chambers and chamber-specific mechanisms utilized during regeneration in vertebrates. Few signals are known to be required that specifically direct atrial development, with specific regulators of atrial regeneration not being understood. The specific aims of this proposal are to elucidate the mechanisms by which a syntenic long non-coding RNA (lncRNA) family limits the expression of Nr2f transcription factors and decipher how Nr2f protein levels affect atrial heterogeneity during development and atrial regeneration in adult zebrafish. The studies in this proposal are relevant to human health as numerous genomic analyses now indicate that mutations in Nr2f2 are associated with CHDs, in particular ASDs in humans. While Nr2f2 knockout mice and in vitro studies with human stem cells have revealed requirements for both Nr2f1 and Nr2f2 in atrial development, the mechanisms by which Nr2f proteins direct proper atrial development are not completely understood. Importantly, there is currently no understanding of lncRNA-dependent mechanisms regulating Nr2f proteins. Our analysis of a lncRNA we call as-oca shows that in vivo it represses the translation of nr2f1a, the functional equivalent of mammalian Nr2f2. Moreover, we find that Nr2f1a levels regulate previously unrecognized heterogeneity of atrial cardiomyocytes in the embryonic atrium and atrial regeneration. In Aim 1, we will examine the specific mechanism that as-oca inhibits nr2f1a translation and the conservation of this mechanism among the NR2F-associated lncRNA family in human induced pluripotent stem cells. In Aim 2, we will examine the requirements of Nr2f1a and canonical Wnt signaling in generating atrial cardiomyocyte diversity and the transcriptional signature of a previously unrecognized atrial subpopulation. In Aim 3, we will examine the requirement of the epicardium in atrial regeneration and requirement of Nr2f1a within the atrial epicardium. Because Nr2f transcription factors play conserved roles in atrial development of all vertebrates, these studies will dramatically improve our understanding of post-transcriptional mechanisms regulating normal vertebrate atrial development and unique mechanisms employed during atrial regeneration. Ultimately, these studies will garner a foundation of knowledge that can be used to improve therapies capable of preventing and ameliorating CHDs and efficiently repairing injured hearts.