Regulation of neuroectoderm morphogenesis by Nodal signaling programs

Nodal 信号传导程序对神经外胚层形态发生的调节

• 批准号: 10606406
• 负责人: Alyssa Nicole Emig
• 金额: $ 4.77万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-03-01 至 2025-02-28
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10606406
• 关键词: Affect; Anencephaly and spina bifida X linked; Anterior; Automobile Driving; Behavior; Blastoderm; Candidate Disease Gene; Cell Communication; Cells; Childhood; Complex; Congenital Abnormality; Coupled; Data; Development; Embryo; Embryonic Development; Endoderm; Ensure; Event; Future; Genes; Genetic; Genetic Transcription; Germ Layers; Individual; Intercalated Cell; Knowledge; Ligands; Literature; Mesoderm; Modeling; Morphogenesis; Neural Fold; Neural Tube Closure; Neural Tube Defects; Neural tube; Neuroectoderm; Nodal; Organism; Play; Pregnancy; Prevalence; Process; Regulation; Research; Role; Series; Severities; Shapes; Signal Pathway; Signal Transduction; Signaling Molecule; Specific qualifier value; Spinal Cord; Spinal Dysraphism; Spontaneous abortion; Techniques; Testing; Time; Tissues; Transgenic Organisms; Vertebrates; Zebrafish; blastomere structure; brain shape; cell motility; chordin; constitutive active receptor; embryo cell; gastrulation; gene function; in vivo; in vivo Model; innovation; knock-down; loss of function; morphogens; mortality; novel; optogenetics; overexpression; polarized cell; programs; receptor; response; transcriptome sequencing; vertebrate embryos

Summary Embryonic development is a series of tightly regulated events that build a single cell into a complex organism. A key milestone in early embryonic development is gastrulation, when the body plan is first shaped by the behaviors of thousands of individual cells. However, how these cells communicate to ensure proper morphogenesis is not completely understood. Mesoderm and neuroectoderm (NE, future neural tube) tissue morphogenesis is driven by convergence and extension (C&E), when cells intercalate to simultaneously narrow and elongate the body axis and bring the neural folds together to ensure proper neural tube closure. Disruptions in these highly conserved cell movements can result in neural tube defects that affect many pregnancies worldwide. Nodal is a well conserved signaling pathway that is active during gastrulation and most well-known for the role it plays in mesoderm and endoderm specification in vertebrates. However, little is understood about the role of Nodal in C&E morphogenesis independent of mesoderm formation, particularly in NE. By utilizing zebrafish ex vivo and in vivo models, I will study the role of Nodal specifically in morphogenesis independent of its better-known function during tissue specification. To examine the role of Nodal underlying NE morphogenesis, I can independently analyze NE extension using ex vivo zebrafish blastoderm explants, naïve clusters of embryonic cells that form all three germ layers and undergo C&E morphogenesis in response to exogenous Nodal signaling. An early peak of Nodal signaling in explants promotes mesoderm extension and specification. However, preliminary data from our lab demonstrated that a relatively delayed peak of Nodal signaling promotes NE- specific C&E morphogenesis that is independent of its role in mesoderm specification. This suggests that the temporal regulation of Nodal regulates NE-specific morphogenesis. Based on my promising preliminary data, I hypothesize that Nodal signaling activates a novel, temporally regulated, NE-specific transcriptional program that drives C&E morphogenesis independent of mesoderm specification. To test this hypothesis, I propose 3 aims: Aim 1 will investigate the role of temporal Nodal signaling dynamics in NE-specific morphogenesis using optogenetic Nodal receptors to precisely manipulate signaling in embryonic explants. In Aim 2, I will restore Nodal signaling specifically within the NE of Nodal-deficient zebrafish embryos using innovative transgenic lines to determine whether Nodal can drive in vivo NE extension in the absence of mesoderm. Finally, in Aim 3 I will perform over expression and knock-down of temporally regulated candidate genes to determine if they are drivers of NE-specific extension both explants and in vivo. This proposal will define the foundational knowledge on the primary role of Nodal in NE-specific morphogenesis, disruptions in which may contribute to neural tube defect prevalence and severity.

总结 胚胎发育是一系列严格调控的事件，将单个细胞构建成复杂的有机体。一 早期胚胎发育的一个重要里程碑是原肠胚形成，此时， 成千上万的细胞。然而，这些细胞如何沟通，以确保适当的形态发生是不 完全理解中胚层和神经外胚层（NE，未来的神经管）组织形态发生是由 通过会聚和伸展（C&E），当细胞插入同时缩小和延长身体时， 轴，使神经褶皱在一起，以确保适当的神经管关闭。在这些高度 保守的细胞运动会导致神经管缺陷，影响世界各地的许多孕妇。Nodal是一个 在原肠胚形成期间活跃的非常保守的信号传导途径，最为人所知的是它在 脊椎动物中胚层和内胚层的特化。然而，人们对Nodal在以下方面的作用了解甚少： C&E形态发生独立于中胚层形成，特别是在NE。通过利用斑马鱼离体和 在体内模型中，我将研究Nodal在形态发生中的作用， 在组织规范期间发挥作用。为了研究Nodal在NE形态发生中的作用，我可以 使用离体斑马鱼胚盘外植体、未处理的胚胎细胞簇和未处理的胚胎细胞簇独立地分析NE延伸 形成所有三个胚层并响应外源Nodal信号而经历C&E形态发生的细胞。 外植体中Nodal信号的早期峰值促进中胚层延伸和特化。然而，在这方面， 我们实验室的初步数据表明，Nodal信号传导的相对延迟的峰值促进NE- 特异性C&E形态发生，独立于其在中胚层特化中的作用。这表明 Nodal的时间调节调节NE特异性形态发生。根据我的初步数据，我 假设Nodal信号激活一种新的、时间调节的NE特异性转录程序 驱动C&E形态发生独立于中胚层特化。为了检验这个假设，我提出3 目的：目的1将研究时间节点信号动力学在NE特异性形态发生中的作用， 光遗传学Nodal受体，以精确操纵胚胎外植体中的信号传导。在目标2中，我将恢复 使用创新的转基因品系在Nodal缺陷斑马鱼胚胎NE内特异性Nodal信号传导 以确定Nodal是否可以在不存在中胚层的情况下驱动体内NE延伸。最后，在目标3中，我将 进行时间调节的候选基因的过表达和敲低，以确定它们是否 NE特异性延伸的驱动因子，包括外植体和体内。本提案将定义基础知识 Nodal在NE特异性形态发生中的主要作用，其中的破坏可能有助于神经管 缺陷发生率和严重程度。