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.

项目摘要 器官发生需要执行交织的图案化过程， 一个器官的组成部分，具有精致的特异性。在胚胎心脏的背景下， 每个心腔内的起搏细胞都具有独特的属性：例如，位于心腔内的起搏细胞。 心房流入道（IFT）具有特定的传导特性，这些传导特性是其在启动心房收缩中的作用不可或缺的。 心跳心脏起搏活动必须限制在心脏的离散区域，以避免 心律失常，但我们还没有完全了解定义IFT维度的遗传途径。 如何在IFT中建立适当数量的特化心肌细胞？先前的研究 显示IFT祖细胞栖息在前侧板中胚层（ALPM）的离散外围区域。 此外，我们已经证明，典型的Wnt信号在这些外围区域是活跃的， 配体Wnt5b起驱动IFT分化的作用。因此，Wnt信号传导在促进IFT中起关键作用 虽然Wnt通路的活性在ALPM的发育过程中起着重要作用，但我们还不清楚Wnt通路的活性是如何被限制在ALPM的边缘的。 在这里，我们建议利用一套遗传和胚胎学方法在斑马鱼， 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限制， 两个阶段的过程，不同的信号通路在连续的发展阶段。一是在 在早期胚胎中，我们提出Hedgehog（Hh）信号限制了祖细胞在胚胎中的分配。 IFT血统。后来，在ALPM中，我们提出Fgf信号传导加强了对IFT数量的限制。 通过限制Wnt信号传导的分布来抑制心肌细胞。我们的初步数据显示， Hh和Fgf信号传导的先前未被认识的作用，并提出了一种新的分子模型， 限制IFT大小的机制。为了测试这个模型，我们将使用功能丧失和功能获得 分析、命运作图和镶嵌分析，以便（1）确定Hedgehog信号传导是否抑制了 IFT祖细胞的特化和（2）确定Fgf信号传导是否限制IFT祖细胞的分化 心肌细胞此外，我们的模型预测，IFT祖细胞具有不同的分子， 在它们明显分化为IFT心肌细胞之前，它们具有这些特征。为了验证这一点，我们将（3）定义 通过整合空间和转录组学数据，揭示了IFT祖细胞的发育路径， 指定IFT谱系的信号传导途径为IFT心肌的分化设置了阶段。 总之，我们提出的研究将为信号通路网络提供新的见解， 控制IFT尺寸，从而为心脏模式的调节提供新的范例。此外，委员会认为， 我们的工作有可能揭示先天性心脏传导的发育起源 疾病，也可能促进再生医学的未来创新。