Investigating collective myocardial cell movement during heart tube formation

研究心管形成过程中心肌细胞的集体运动

• 批准号: 10439340
• 负责人: Joshua Eli Bloomekatz
• 金额: $ 41.2万
• 依托单位: UNIVERSITY OF MISSISSIPPI
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10439340
• 关键词: Ablation; Affect; Animal Model; Anterior; Architecture; Automobile Driving; Bilateral; Biological; Biomechanics; Cardiac; Cardiac Myocytes; Cardiovascular system; Cell Shape; Cell Size; Cell physiology; Cells; Communication; Congenital Abnormality; Data; Defect; Development; Developmental Biology; Disease; Educational process of instructing; Endoderm; Environment; Etiology; Event; Exhibits; Foundations; Future; Genes; Genetic; Genetic Techniques; Goals; Heart; Heart Abnormalities; Heart Diseases; Image; Individual; Laboratories; Lasers; Lateral; Lead; Ligands; Location; Medial; Mediating; Mesoderm; Mission; Mississippi; Molecular; Morphogenesis; Movement; Mus; Mutation; Myocardial; Myocardial dysfunction; Myocardium; Organ; Organogenesis; Pathogenesis; Pathway interactions; Pattern; Platelet-Derived Growth Factor; Platelet-Derived Growth Factor alpha Receptor; Population; Process; Property; Pseudopodia; Regulation; Research; Resolution; Rest; Rheology; Role; Signal Transduction; Signaling Molecule; Students; Techniques; Testing; Time; Tissues; Training; Transgenes; Tube; Universities; Vertebrates; Zebrafish; base; cardiogenesis; cell behavior; cell motility; citizen science; genetic analysis; graduate student; in vivo; insight; mutant; paracrine; programs; response; small molecule inhibitor; source localization; undergraduate student; university student; viscoelasticity

Project Summary Organ formation is critically regulated by inter-tissue communication. The architecture of the mature heart is a result of sequential morphogenetic events, starting with the primitive heart tube, which is the foundation upon which the rest of the heart is built. The process of building the primitive heart tube starts with the collective movement of myocardial cells from bilateral locations in the anterior lateral plate mesoderm to the midline, a process called cardiac fusion which is conserved in all vertebrates. Genetic analysis has revealed that the adjacent endoderm is critical for these movements. However, the signals or molecules by which the endoderm communicates to the myocardium remain unknown. Furthermore, the molecular mechanism by which myocardial cells in vertebrates respond to these signals and collectively move towards the midline is also poorly understood. To elucidate these mechanisms, undergraduate and graduate students from the University of Mississippi will take a multi-dimensional approach examining cardiac fusion at the tissue, molecular, cellular and biomechanical level. We have found that mutations in the Platelet-derived growth factor receptor alpha (Pdgfra) leads to cardiac fusion defects in both zebrafish and mice. Myocardial movement appears to occur in response to a localized source of the PDGF ligand pdgf-aa, which we found is expressed in the endoderm medially adjacent to pdgfra expression in the myocardium. Furthermore, our preliminary data reveals that disruption of PI3K signaling in zebrafish also causes cardiac fusion defects. And that myocardial cells exhibit protrusions and display heterogenous changes in cell shape during cardiac fusion. Together, this data suggests the hypothesis that paracrine PDGF signals from the endoderm activates Pdgfra-mediated PI3K signaling in the myocardium to create medial oriented migratory protrusions which create asymmetric biomechanical tension in the myocardium facilitating medial movement. We will test this hypothesis by using tissue- specific genetic techniques to determine the tissues in which pdgfra and pdgf-aa function (Aim 1) as well as determine whether PI3K signaling and migratory protrusions are activated downstream of Pdgfra (Aim2). Additionally, we will use micro-rheology and micro-laser ablation in combination with pdgfra mutants to examine the biomechanical properties in the myocardium controlled by PDGF signaling (Aim 3). In summary, these studies are likely to elucidate the molecular mechanisms that underlie how myocardial cells sense and respond to their local environment and in the long-term identify the fundamental principles that underlie cardiac morphogenesis in both development and disease. Furthermore, this proposal will help to establish a research program that intertwines student research opportunities with the discovery of fundamental molecular mechanisms underlying inter-tissue communication during organ morphogenesis.

项目概要 器官形成受到组织间通讯的严格调节。成熟心灵的架构 是连续形态发生事件的结果，从原始心管开始，这是 心的其余部分都建立在这个基础上。建造原始心管的过程开始 随着心肌细胞从前侧板两侧位置的集体运动 中胚层到中线，这个过程称为心脏融合，在所有脊椎动物中都是保守的。遗传 分析表明，邻近的内胚层对于这些运动至关重要。然而，信号 或内胚层与心肌通讯的分子仍然未知。此外， 脊椎动物心肌细胞响应这些信号的分子机制 集体走向中线也知之甚少。为了阐明这些机制， 密西西比大学的本科生和研究生将采取多维的 在组织、分子、细胞和生物力学水平上检查心脏融合的方法。我们有 发现血小板衍生生长因子受体α（Pdgfra）的突变导致心脏融合 斑马鱼和小鼠都有缺陷。心肌运动似乎是对局部的反应而发生的 PDGF 配体 pdgf-aa 的来源，我们发现它在邻近内侧的内胚层中表达 pdgfra 在心肌中的表达。此外，我们的初步数据表明 PI3K 的破坏 斑马鱼的信号传导也会导致心脏融合缺陷。心肌细胞表现出突起 并在心脏融合过程中显示出细胞形状的异质变化。总之，这些数据表明 假设来自内胚层的旁分泌 PDGF 信号激活 Pdgfra 介导的 PI3K 信号 心肌产生向内定向的迁移突出，从而产生不对称的生物力学 心肌张力促进内侧运动。我们将通过使用组织来检验这个假设 特定的遗传技术来确定 pdgfra 和 pdgf-aa 发挥功能的组织（目标 1） 确定 PI3K 信号传导和迁移突起是否在 Pdgfra 下游被激活 （目标2）。此外，我们将结合 pdgfra 使用微流变学和微激光烧蚀 突变体来检查由 PDGF 信号控制的心肌生物力学特性（目的 3）。总之，这些研究可能会阐明其背后的分子机制。 心肌细胞感知并响应其局部环境，并长期识别 发育和疾病中心脏形态发生的基本原理。 此外，该提案将有助于建立一个将学生研究交织在一起的研究计划 发现组织间基本分子机制的机会 器官形态发生过程中的通讯。