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 器官发生需要执行雕刻不同功能的交织图案过程 具有精美特异性的器官的组件。在胚胎心脏的背景下 在每个心脏室内都有独特的属性：例如，驻留在 心房流入道（IFT）具有特定的导电性能，这些特性与它们在启动的作用不可或缺 心跳。心脏起搏活动必须局限于心脏的离散区域，以避免 心律不齐，但我们尚未完全理解定义IFT尺寸的遗传途径。 如何在IFT建立适当数量的专门心肌细胞？先前的研究已有 表明IFT祖细胞居住在前侧板中胚层（ALPM）的离散区域。 此外，我们已经证明了规范的Wnt信号在这些偏远地区处于活动状态，并且 配体WNT5B起作用IFT分化。因此，Wnt信号在促进IFT中起关键作用 开发，但我们尚不了解Wnt途径活动如何仅限于ALPM的边缘。 在这里，我们建议利用斑马鱼中可用的遗传和胚胎学方法 为了识别限制IFT维度的基本模式机制。 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 两阶段过程，具有在连续的发育阶段运行的不同信号通路。首先，在 早期的胚胎，我们提出刺猬（HH）信号限制了祖细胞分配到 IFT谱系。后来，在ALPM中，我们提出FGF信号加强了对IFT数量的约束 心肌细胞通过限制Wnt信号的分布。一起，我们的初步数据突出显示 以前在HH和FGF信号传导中都没有批准的作用，并提出了分子的新型模型 限制IFT大小的机制。为了测试该模型，我们将采用损失和功能收益 分析，命运映射和马赛克分析，以（1）确定刺猬信号是否限制 IFT祖细胞的规范，以及（2）确定FGF信号是否限制了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 特征在其明显分化为IFT心肌细胞之前。为了测试这一点，我们将（3）定义 通过整合空间和转录组数据，IFT祖细胞的发育路径，从而揭示了如何 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，我们提出的研究将提供对信号通路网络的新见解 控制IFT维度，从而照亮了针对心脏模式的新范式。而且， 我们的工作有可能阐明先天性心脏传导的发育起源 疾病，还可能促进再生医学的未来创新。