The role of ZIC3 within cardiomyocyte precursors in cardiac morphogenesis

项目总结 尽管对心脏发育的理解日益复杂，但心脏发育的潜在机制 先天性心脏病是最常见的出生缺陷，其病因、外显性和表型多样性， 都没有被很好地理解。这对风险分层、改进的治疗方法和预防 先心病。我们研究了异位综合征的遗传和发育基础，这是一种多系统障碍。 有一系列先天性心脏病，至少部分可归因于心脏循环形态发生异常。 尽管已证实胚胎早期左-右轴形成异常 发展导致先天性心脏病在异位，所遇到的室腔形态缺陷较多 比简单地破坏左右轴所预期的要复杂得多。我们假设严重的异质性 CHDS是心脏祖细胞异常细胞命运的结果，这是一种独特的CHD发病机制 来自后来的LR图案化介导的CHD。X-小鼠模型的单细胞RNA测序(scRNA-seq) 连锁异质性，Zic3缺失小鼠，支持这一假说。数据显示异常的中胚层与 神经外胚层在心脏发生之前的分配，导致心肌细胞的异常命运。与 我们关于Zic3基因缺失小鼠异常原始条纹形成的数据，这些研究揭示了以下必要 ZIC3基因调控网络(GRN)在细胞多能性向LR转变过程中的研究 模式，以了解不同类型CHD的机制基础。我们将配合这次调查 凭借我们在基因组分析和全基因组测序(WGS)数据方面的专业知识， 异位型冠心病患者队列。我们的初步数据显示冠心病患者罕见的变异负荷增加 候选基因，提示复杂的CHD可能是由多个 易感等位基因。这种方法将用于测试单基因和少基因疾病的候选基因。 协会。本研究的目的是：1)检验将ZIC3DNA-入住率数据与 ZIC3功能丧失引起的转录和表观遗传学变化将识别心脏新的GRN 2)检验ZIC3GRN内的遗传变异与CHD相关的假设。 这一建议的首要假设是ZIC3调节网络基因是室性心脏病的危险因素 导致冠心病的形态发生缺陷。通过鉴定ZIC3通路在原肠形成过程中的过渡态 对于心脏形成，我们将发现心脏形成所需的不同的ZIC3GRN。这一点的整合 多组学数据将为心脏祖细胞规格提供新的见解。调查其重要性 在这些ZIC3 GRN和发育阶段的特定途径中，人类对冠心病的易感性将提供关键的 翻译信息。总而言之，我们将确定对密封室重要的新的ZIC3 GRN 并提供了有关单基因和少基因途径贡献的基本信息。 调控心肌细胞命运与人类异位性先心病的发展。

PROJECT SUMMARY Despite an increasingly sophisticated understanding of cardiac development, the mechanisms underlying the causes, penetrance, and phenotypic diversity of congenital heart defects (CHDs), the most common birth defect, are not well understood. This represents a barrier to risk stratification, improved therapeutics, and prevention of CHD. We have studied the genetic and developmental basis of heterotaxy syndrome, a multisystem disorder with a spectrum of CHDs that are attributable, at least in part, to abnormal cardiac looping morphogenesis. Although it has been proven that abnormalities in left-right (LR) axis formation during early embryonic development lead to CHDs in heterotaxy, the ventricular chamber morphogenic defects encountered are more diverse than would be expected from simple disruption of the LR axis. We hypothesize that severe heterotaxy CHDs result from abnormal cell fate of cardiac progenitors and that this is a distinct CHD causing mechanism from later LR patterning-mediated CHDs. Single cell RNA sequencing (scRNA-seq) from a mouse model of X- linked heterotaxy, Zic3 null mice, supports this hypothesis. The data demonstrate an abnormal mesoderm versus neuroectoderm allocation prior to cardiogenesis that results in abnormal cardiomyocyte cell fate. Combined with our data on abnormal primitive streak formation in Zic3 null mice, these studies reveal an essential need to investigate the ZIC3 gene regulatory networks (GRNs) during the transition from cell pluripotency through LR patterning to understand the mechanistic underpinnings of a diverse set CHDs. We will pair this investigation with our expertise in genomic analyses and whole genome sequencing (WGS) data in our well-phenotyped cohort of heterotaxy CHD patients. Our preliminary data demonstrate increased rare variant burden in CHD candidate genes, suggesting that complex CHD can result from combinatorial interactions of multiple susceptibility alleles. This approach will be used to test candidate genes for monogenic and oligogenic disease association. The aims of this study are to: 1) test the hypothesis that integrating ZIC3 DNA-occupancy data with transcriptional and epigenetic changes caused by ZIC3 loss-of-function will identify novel GRNs for cardiac morphogenesis; and 2) test the hypothesis that genetic variation within the ZIC3 GRN is associated with CHD. The overarching hypothesis of this proposal is that ZIC3 regulatory network genes are risk factors for ventricular morphogenesis defects that result in CHD. By identifying ZIC3 pathways during transition states from gastrulation to cardiogenesis, we will discover distinct ZIC3 GRNs required for heart formation. The integration of this multiomics data will provide novel insight into cardiac progenitor cell specification. Investigating the importance of these ZIC3 GRNs and developmental-stage specific pathways to human CHD susceptibility will provide critical translational information. Collectively, we will have identified novel ZIC3 GRNs important for chamber morphogenesis and provided essential information on monogenic and oligogenic contributions of pathways regulating cardiac cell fate to the development of human heterotaxy CHDs.