Modulating Morphogenesis: Genetic Regulation of Cardiac Cell Movement in Zebrafish

调节形态发生：斑马鱼心肌细胞运动的遗传调控

• 批准号: 9330923
• 负责人: DEBORAH YELON
• 金额: $ 38.75万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-15 至 2020-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9330923
• 关键词: Address; Architecture; Automobile Driving; Behavior; Bilateral; Birth; Cardiac; Cardiac Myocytes; Cells; Communities; Confocal Microscopy; Congenital Heart Defects; Cues; Data; Deposition; Destinations; Embryo; Endoderm; Extracellular Matrix; Future; Genes; Genetic; Heart; Heart Abnormalities; Individual; Integral Membrane Protein; Investigation; Ligands; Light; Live Birth; Medial; Membrane; Modeling; Molecular; Morphogenesis; Movement; Mus; Mutation; Myocardial; Myocardium; Organ; Organogenesis; Pathway interactions; Pattern; Phase; Platelet-Derived Growth Factor; Platelet-Derived Growth Factor Receptor; Play; Population; Process; Proteins; Proteomics; Regulation; Research; Role; Route; Signal Transduction; Structure; Testing; Time; Tissue Engineering; Tissues; Transgenes; Tube; Work; Zebrafish; cardiac repair; cardiogenesis; cell behavior; cell motility; cohesion; congenital heart disorder; extracellular; insight; mutant; novel; three dimensional structure; time use; vertebrate genome

PROJECT SUMMARY Organogenesis relies upon the carefully coordinated regulation of collective cell movement, in which a group of cells operate as a cohesive entity, coordinating their individual trajectories to reach a common destination. Cardiogenesis, for example, employs collective cell movement during multiple phases of morphogenesis, including the assembly of the heart tube, the protrusion of trabeculae, and the construction of septae. Despite the importance of these morphogenetic processes, we do not yet understand the molecular mechanisms that govern collective cell behavior in the developing heart. In particular, the cues that control the timing and routes of cardiac cell movement remain largely mysterious. Here, we aim to decipher the genetic pathways that control collective cell movement during heart tube assembly in the zebrafish embryo. To build the heart tube, bilateral groups of cardiomyocytes move toward the midline and merge through a process called cardiac fusion. Our prior studies have suggested a model in which interactions between the myocardium, endoderm, and extracellular matrix (ECM) act to facilitate cardiac fusion. However, the elucidation of these tissue-level interactions has not answered key open questions regarding the molecular mechanisms that drive cell behavior. Notably, we do not yet know which signals dictate the direction of cardiomyocyte trajectories or which cues control the rate of cardiomyocyte mobility. It is therefore exciting that we will investigate two novel regulators of cardiomyocyte movement – the platelet-derived growth factor receptor Pdgfra and the transmembrane protein Tmem2 – that are poised to address these unresolved issues. First, to test the hypothesis that medially-located PDGF ligands activate Pdgfra in cardiomyocytes and thereby control the direction of cardiomyocyte movement, we will (a) employ time-lapse analysis to pinpoint the impact of pdgfra on myocardial cell behavior, (b) use tissue-specific transgenes to determine where pdgfra acts to influence cardiac fusion, (c) test whether PDGF ligands act as directional cues for myocardial movement, (d) identify effector pathways acting downstream of Pdgfra in this context, and (e) evaluate whether Pdgfra plays a comparable role during cardiac fusion in mouse. Second, to test the hypothesis that the Tmem2 ectodomain facilitates an efficient rate of myocardial motility through modulation of the ECM, we will (a) employ time-lapse analysis to determine the influence of tmem2 on myocardial cell behavior, (b) determine whether tmem2 has a non-autonomous effect on myocardial movement, (c) test whether Tmem2 regulates cardiac fusion by modulating the ECM, and (d) utilize structure-function and proteomic analyses to identify which domains of Tmem2 are required for its function and which proteins interact with these domains. Together, these studies will reveal essential mechanisms of heart tube assembly, uncover new paradigms for the regulation of collective cardiac cell movement, shed light on the origins of congenital heart disease, and facilitate future tissue engineering approaches for cardiac repair.

项目概要 器官发生依赖于集体细胞运动的仔细协调调节，其中一组 细胞作为一个有凝聚力的实体运作，协调各自的轨迹以到达共同的目的地。 例如，心脏发生在形态发生的多个阶段采用集体细胞运动， 包括心管的组装、小梁的突出和隔膜的构造。 尽管这些形态发生过程的重要性，我们还不了解其分子机制 控制发育中心脏的集体细胞行为，特别是控制时间和路线的线索。 心肌细胞运动的机制在很大程度上仍然是个谜。 在这里，我们的目标是破译控制心管期间集体细胞运动的遗传途径 斑马鱼胚胎中的组装 为了构建心管，双侧心肌细胞群向着心脏方向移动。 我们之前的研究提出了一种模型，其中线和融合通过称为心脏融合的过程。 心肌、内胚层和细胞外基质 (ECM) 之间的相互作用促进心脏融合。 然而，对这些组织水平相互作用的阐明并没有回答有关 值得注意的是，我们还不知道哪些信号决定了方向。 心肌细胞轨迹或控制心肌细胞运动速率的线索因此令人兴奋。 我们将研究两种新型的心肌细胞运动调节剂——血小板衍生生长因子 受体 Pdgfra 和跨膜蛋白 Tmem2 – 有望解决这些未解决的问题。 首先，检验位于内侧的 PDGF 配体激活心肌细胞中的 Pdgfra 的假设，从而 控制心肌细胞运动的方向，我们将（a）采用延时分析来查明影响 pdgfra 对心肌细胞行为的影响，(b) 使用组织特异性转基因来确定 pdgfra 在何处发挥作用 影响心脏融合，(c) 测试 PDGF 配体是否充当心肌运动的方向线索，(d) 确定在这种情况下作用于 Pdgfra 下游的效应器途径，并且 (e) 评估 Pdgfra 是否发挥作用 其次，检验 Tmem2 胞外域的假设。 通过调节 ECM 促进心肌运动的有效速率，我们将 (a) 采用延时 分析以确定 tmem2 对心肌细胞行为的影响，(b) 确定 tmem2 是否具有 对心肌运动的非自主效应，(c) 测试 Tmem2 是否通过以下方式调节心脏融合： 调节 ECM，以及 (d) 利用结构功能和蛋白质组分析来识别哪些域 Tmem2 是其功能所必需的，以及哪些蛋白质与这些结构域相互作用。 这些研究将共同​​揭示心管组装的基本机制，揭示心脏管组装的新范例 集体心肌细胞运动的调节，揭示先天性心脏病的起源，以及 促进未来用于心脏修复的组织工程方法。