Cilia in Heart Development and Disease

先天性心脏病(CHD)是最常见的出生缺陷，影响到所有活产婴儿的1%。而当 约90%的CHD患者存活到成年，有许多并发症使CHD成为 日益严重的公共卫生问题。大量冠心病患者的基因组分析 发现了导致冠心病的显著遗传因素，但病因和临床结果之间的联系仍然存在。 一个重要的问题。当我开始寻找先天性心脏病的病因时，我发现纤毛是 左-右(LR)轴与心脏发育，最近，作为儿科心脏基因组学的一部分 发现了影响纤毛和染色质重塑的突变的重大贡献 基因与人类冠心病的关系。然而，纤毛功能障碍究竟如何影响CHD的问题仍然存在。 无人接听。我召集了一组在老鼠和斑马鱼方面有专长的合作调查员 开发、活细胞成像、光遗传学和基因组学多管齐下理解 纤毛在心脏发育中的核心作用，长期目标是利用这些数据进行 改善冠心病临床结局的基因组和临床研究。首先，我们将解决长期存在的 纤毛如何引导心脏下缘不对称的问题。我们将使用单细胞RNAseq来定义细胞 左-右组织器(LRO)的组成，这是一种短暂的纤毛器官，对指导心脏 不对称。然后，我们将建立连接LRO纤毛信号与心脏LR的分子机制 小鼠和斑马鱼胚胎的发育。总之，这些实验将通过以下方式揭示这种机制 胚胎决定了LR的不对称性，并提供了将为寻找人类CHD提供信息的基因集 候选基因。其次，我们将研究纤毛在心脏瓣膜形成中的作用。我们发现了 在斑马鱼心脏假定的房室瓣膜区域的动态的、流动敏感的纤毛，并将测试 假设阀门规格是由以下界面上发生的机械力驱动的 差动收缩腔，瓣膜纤毛是机械换能器，导致 KLF2/KLF4转录与下游瓣膜形态发生第三，我们将揭开 表观遗传因素影响心脏发育。染色质重塑基因在人类中的重要作用 CHD提出了这样一个问题：这些基因中是否有任何一个在转录上调节心脏发育中的纤毛。我们 已经发现组蛋白H_2B单素化(H_2Bub1)在转录上调节纤毛功能 LRO。我们现在正在测试H_2Bub1如何影响小鼠胚胎和人类IPSC的心脏发育。 通过纤毛依赖和/或纤毛非依赖机制获得心肌细胞(S)。我们的长期目标是 将基本的生物和基因组数据转化为临床影响将通过返回机制来解决 我们纤毛的遗传数据将用于PCGC CHD基因组学项目，因此由此产生的发现将导致 到冠心病患者的个性化用药。 好了！

Congenital Heart Disease (CHD) is the most common birth defect affecting 1% of all live born infants. While ~90% of patients with CHD survive into adulthood, there are many comorbidities that make CHD an increasingly significant public health problem. Genomic analyses of large cohorts of CHD patients have identified a significant genetic contribution to CHD, but the link between etiology and clinical outcome remains an important question. When I began my search for the cause of CHD, I identified the cilium as being central to left-right (LR) axis and cardiac development, and most recently, as part of the Pediatric Cardiac Genomics Consortium (PCGC), identified significant contributions from mutations affecting cilia and chromatin remodeling genes to human CHD. However, the question of how cilia dysfunction precisely influences CHD remains unanswered. I have assembled a group of co-investigators with expertise in mouse and zebrafish development, live-cell imaging, optogenetics and genomics to take a multi-pronged approach to understanding the central role of the cilium in heart development with the long-term goal of leveraging this data with ongoing genomic and clinical studies to improve clinical outcomes of CHD. First, we will resolve the long-standing question of how cilia instruct cardiac LR asymmetry. We will use single-cell RNAseq to define the cellular composition of the left-right organizer (LRO), a transient ciliated organ that is essential for instructing cardiac asymmetry. We will then establish the molecular mechanism linking cilia signaling at the LRO to cardiac LR development in mouse and zebrafish embryos. Together these experiments will uncover the mechanism by which an embryo determines LR asymmetry, and provide gene sets that will inform the search for human CHD candidate genes. Second, we will investigate the role of cilia in cardiac valve formation. We have found dynamic, flow-sensitive cilia in the presumptive atrio-ventricular valve region of the zebrafish heart, and will test the hypothesis that valve specification is driven by the mechanical forces occurring at interfaces between differentially contracting chambers, and that valve cilia are the mechanotransducers leading to changes in transcription of klf2/klf4 and downstream valve morphogenesis. Third, we will unravel the mechanism by which epigenetic factors influence cardiac development. The important role of chromatin remodeling genes in human CHD has raised the question whether any of these transcriptionally regulate cilia in heart development. We have already found that histone H2B monoubiquitination (H2BUb1) transcriptionally regulates cilia function at the LRO. We are now testing how H2BUb1 affects cardiac development in mouse embryos and human iPSC- derived cardiomyocytes through cilia-dependent and/or cilia-independent mechanism(s). Our long-term goal of translating the basic biologic and genomic data to clinical impact will be addressed by returning mechanistic and genetic data from our cilia work to the PCGC CHD genomics project so that the resulting discoveries lead to personalized medicine for patients with CHD. !