Genetic regulation of cardiac inflow tract formation in zebrafish

斑马鱼心脏流入道形成的遗传调控

• 批准号: 10405548
• 负责人: Neil C Chi
• 金额: $ 49.77万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-05-14 至 2025-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10405548
• 关键词: Anterior; Arrhythmia; Cardiac; Cardiac Myocytes; Characteristics; Comprehension; Data; Development; Dimensions; Disease; Embryo; Embryonic Heart; Erinaceidae; Evaluation; Future; Gene Expression; Genes; Genetic; Genetic Epistasis; Heart; Heart Atrium; Lateral; Ligands; Light; Mesoderm; Modeling; Molecular; Molecular Profiling; Mosaicism; Myocardium; Organ; Organism; Organogenesis; Pacemakers; Pathway interactions; Pattern; Pharmacology; Phase; Play; Process; Property; Regenerative Medicine; Regulation; Resolution; Role; Signal Pathway; Signal Transduction; Specific qualifier value; Specificity; Testing; Tissues; WNT Signaling Pathway; Work; Zebrafish; antagonist; congenital heart disorder; gain of function; improved; innovation; insight; molecular modeling; mutant; network models; nodal myocyte; novel; predictive modeling; progenitor; regenerative approach; single-cell RNA sequencing; smoothened signaling pathway; stem cells; transcriptomics

PROJECT SUMMARY Organogenesis requires the execution of interwoven patterning processes that sculpt the distinct functional components of an organ with exquisite specificity. In the context of the embryonic heart, specific territories within each cardiac chamber take on unique attributes: for example, the pacemaker cells that reside within the atrial inflow tract (IFT) have particular conductive properties that are integral to their role in initiating the heartbeat. Cardiac pacemaking activity must be confined to a discrete region of the heart in order to avoid arrhythmia, but we do not yet fully understand the genetic pathways that define the dimensions of the IFT. How are an appropriate number of specialized cardiomyocytes established at the IFT? Prior studies have shown that IFT progenitor cells inhabit discrete outlying regions of the anterior lateral plate mesoderm (ALPM). Moreover, we have demonstrated that canonical Wnt signaling is active in these outlying regions and that the ligand Wnt5b acts to drive IFT differentiation. Thus, Wnt signaling plays a key role in promoting IFT development, but we do not yet understand how Wnt pathway activity is restricted to the edges of the ALPM. Here, we propose to utilize the suite of genetic and embryological approaches available in the zebrafish in order to identify essential patterning mechanisms that constrain IFT dimensions. Importantly, our preliminary studies suggest that the number of IFT cardiomyocytes is constrained through a two-phase process, with distinct signaling pathways operating at successive developmental stages. First, in the early embryo, we propose that Hedgehog (Hh) signaling restricts the allocation of progenitor cells into the IFT lineage. Later, in the ALPM, we propose that Fgf signaling reinforces constraints on the number of IFT cardiomyocytes by restricting the distribution of Wnt signaling. Together, our preliminary data highlight previously unappreciated roles for both Hh and Fgf signaling and suggest a novel model for the molecular mechanisms that restrict the size of the IFT. To test this model, we will employ loss- and gain-of-function analysis, fate mapping, and mosaic analysis in order to (1) determine whether Hedgehog signaling constrains specification of IFT progenitor cells and (2) ascertain whether Fgf signaling constrains differentiation of IFT cardiomyocytes. In addition, our model predicts that IFT progenitor cells possess distinct molecular characteristics prior to their overt differentiation into IFT cardiomyocytes. To test this, we will (3) define the developmental path of IFT progenitors by integrating spatial and transcriptomic data, thereby revealing how the signaling pathways that specify the IFT lineage set the stage for differentiation of the IFT myocardium. Taken together, our proposed studies will provide novel insight into the network of signaling pathways that control IFT dimensions, thereby illuminating new paradigms for the regulation of cardiac patterning. Moreover, our work has the potential to shed light on the developmental origins of congenital cardiac conduction disorders and may also facilitate future innovations in regenerative medicine.

项目总结 器官发生需要执行相互交织的图案化过程，以雕刻出不同的功能 器官的组成部分具有精致的专一性。在胚胎心脏的背景下，特定的领土 在每个心腔内具有独特的属性：例如，驻留在 心房流入道(IFT)具有特殊的传导特性，这些特性是其在起搏过程中所不可或缺的。 心跳。心脏起搏活动必须限制在心脏的一个离散区域，以避免 心律失常，但我们还不完全了解定义IFT维度的遗传途径。 IFT如何建立合适数量的特化心肌细胞？先前的研究已经 结果显示，IFT前体细胞位于前外侧板中胚层(ALPM)的离散边远区域。 此外，我们已经证明了规范的Wnt信号在这些边远地区是活跃的，并且 配体Wnt5b在促进IFT分化中起作用。因此，Wnt信号在促进IFT中起着关键作用 发展，但我们还不知道Wnt途径的活性如何被限制在ALPM的边缘。 在这里，我们建议利用在斑马鱼中可用的一套遗传和胚胎学方法 以确定约束IFT尺寸的基本图案化机制。 重要的是，我们的初步研究表明，IFT心肌细胞的数量受到 两个阶段的过程，在连续的发育阶段有不同的信号通路运行。首先，在 在早期胚胎中，我们认为Hedgehog(HH)信号限制祖细胞分配到 IFT血统。后来，在ALPM中，我们提出了成纤维细胞生长因子信号加强了对IFT数量的限制 通过限制Wnt信号在心肌细胞中的分布。总而言之，我们的初步数据强调 HH和成纤维细胞生长因子信号转导之前未被认识到的作用，并为分子提出了一个新的模型 限制IFT大小的机制。为了测试这个模型，我们将使用函数损失和函数增益 分析、命运映射和镶嵌分析，以便(1)确定Hedgehog信号是否限制 确定IFT祖细胞的规范和(2)确定成纤维细胞生长因子信号是否抑制IFT的分化 心肌细胞。此外，我们的模型预测IFT祖细胞具有不同的分子 分化为IFT心肌细胞前的特征。为了测试这一点，我们将(3)定义 通过整合空间数据和转录组数据，揭示IFT祖先的发展路径 指定IFT谱系的信号通路为IFT心肌的分化奠定了基础。 综上所述，我们提议的研究将提供对信号通路网络的新见解， 控制IFT的尺寸，从而为心脏模式的调节提供新的范例。此外， 我们的工作有可能阐明先天性心脏传导的发育起源 此外，它还可能促进未来再生医学领域的创新。