Molecular drivers of tissue-specific morphogenetic programs

组织特异性形态发生程序的分子驱动因素

• 批准号: 10650730
• 负责人: Margot L.K. Williams
• 金额: $ 44.35万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-06-22 至 2027-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10650730
• 关键词: Address; Age; American; Animals; Automobile Driving; Brain; Cause of Death; Cells; Child; Congenital Abnormality; Coupled; Defect; Development; Developmental Process; Diagnosis; Embryo; Embryonic Development; Ephrins; Exhibits; Extracellular Matrix; Failure; Family; Future; Gene Expression; Gene Expression Profile; Genes; Germ Layers; Head; Heart; Individual; Instruction; Intuition; Ligands; Link; Mesoderm; Methods; Modeling; Molecular; Morphogenesis; Movement; Neural Fold; Neural Tube Closure; Neural Tube Defects; Neural Tube Development; Neural tube; Neuroectoderm; Nodal; Organ; Pattern; Prevention strategy; Procedures; Process; Reporting; Rod; Role; Shapes; Signal Transduction; Signaling Molecule; Specific qualifier value; Spinal Cord; Tail; Testing; Tissue-Specific Gene Expression; Tissues; Tube; Variant; Zebrafish; cell behavior; cell motility; cell type; embryo cell; embryo tissue; experimental study; gastrulation; genetic manipulation; genetic risk factor; improved; in vivo; innovation; morphogens; neural; notochord; novel; optogenetics; pharmacologic; programs; prospective; receptor; response; transcriptomic profiling; treatment strategy; vertebrate embryos

Project summary Congenital malformations, or birth defects, are the leading cause of death of American children under the age of nine. Neural tube defects (NTDs) are among the most common and devastating congenital malformations, and result from a failure of the neural tube to close during early embryonic development. Neural tube closure requires not only that the paired neural folds raise and fuse together, but also that the neuroectoderm (precursor to the neural tube), narrows sufficiently for the neural folds to meet along the midline. This critical narrowing begins during gastrulation and is coupled to a concurrent anteroposterior (AP) extension of the neuroectoderm that results from the polarized rearrangement of cells into a longer and narrower array. This process, appropriately termed convergence & extension (C&E), is a highly conserved morphogenetic mechanism with essential roles in shaping numerous embryonic tissues and establishing the animal body plan. Neural tube closure and extension of the primary AP embryonic axis are driven by C&E of both the neuroectoderm and the underlying mesoderm, each of which exhibits a distinct suite of cell behaviors and contributes actively to axis extension. It remains poorly understood, however, how tissue identity is coordinated with tissue-specific cell behavior programs. Here, we address the tissue-specific morphogenesis underlying axis extension in zebrafish, a model vertebrate embryo. We recently reported that the TGF- family morphogen Nodal is not only necessary for C&E gastrulation movements in zebrafish, but also sufficient to promote these cell behaviors in otherwise naïve zebrafish embryonic explants. By varying the method of Nodal signaling activation, we can drive tissue- specific C&E of either the neuroectoderm or mesoderm within these explants. Importantly, this allows us to uncouple morphogenesis of individual tissue layers and distinguish the mechanisms that control cell identity from those that control cell movement. Each mode of C&E is associated with a specific developmental peak of Nodal activity and transcriptional profile, leading us to hypothesize that temporal patterns of Nodal activity define tissue-specific morphogenesis via distinct downstream molecular programs. Using cutting-edge optogenetic approaches to precisely manipulate Nodal activity, experiments proposed in Aim 1 will test how variations in temporal signaling dynamics control tissue-specific C&E both in and ex vivo. In Aims 2 and 3, we will define the specific components of each Nodal-dependent gene expression program that are necessary and/or sufficient for tissue-specific C&E of the mesoderm and neuroectoderm, respectively. This proposal leverages the unique advantages of our innovative explant model and optogenetic approaches to identify genes with novel roles in axis extension, thereby advancing a fundamental understanding of neural tube closure essential for improved diagnosis, prevention, and treatment strategies for NTDs.

项目摘要 先天性畸形，或出生缺陷，是美国儿童死亡的主要原因， 九个。神经管缺陷（NTD）是最常见和最具破坏性的先天性畸形之一， 这是由于在早期胚胎发育过程中神经管未能闭合而导致的。神经管闭合 不仅要求成对的神经褶皱隆起并融合在一起，而且要求神经外胚层 （神经管的前体），足够窄以使神经褶皱沿着中线相遇。这一关键 狭窄在原肠胚形成期间开始，并与同时发生的前后（AP）延伸相耦合。 由细胞极性重排形成更长更窄排列的神经外胚层。这 过程，适当地称为收敛和延伸（C&E），是一个高度保守的形态发生过程。 在塑造众多胚胎组织和建立动物身体计划中起着重要作用的机制。 神经管的闭合和原代AP胚胎轴的延伸是由两个细胞的C&E驱动的。 神经外胚层和下面的中胚层，其中每一个都表现出一套不同的细胞行为， 有助于轴的延伸。然而，对于组织特性是如何协调的， 组织特异性细胞行为程序。 在这里，我们解决组织特异性形态发生的基础轴延伸在斑马鱼，一个模型， 脊椎动物胚胎我们最近报道，TGF-β家族形态发生蛋白Nodal不仅是 C&E原肠胚运动在斑马鱼，但也足以促进这些细胞的行为，否则 斑马鱼胚胎移植。通过改变Nodal信号激活的方法，我们可以驱动组织- 这些外植体内的神经外胚层或中胚层的特异性C&E。重要的是，这使我们能够 分离单个组织层的形态发生并区分控制细胞身份的机制 与那些控制细胞运动的细胞不同。C&E的每种模式都与特定的发育高峰有关。 Nodal活性和转录谱，使我们假设Nodal活性的时间模式 通过不同的下游分子程序定义组织特异性形态发生。使用尖端 光遗传学方法来精确操纵Nodal活性，目标1中提出的实验将测试如何 时间信号动力学的变化控制体内和体外的组织特异性C&E。在目标2和3中，我们 将定义每个Nodal依赖性基因表达程序的特定组件， 和/或分别足以用于中胚层和神经外胚层的组织特异性C&E。这项建议 利用我们创新的外植体模型和光遗传学方法的独特优势来识别 在轴延伸中具有新作用的基因，从而推进了对神经管的基本理解。 闭合对于改善NTD的诊断、预防和治疗策略至关重要。