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.

概括 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生物体。 早期胚胎发育的关键里程碑是原肠胚形成，此时身体计划首先由行为形成 然而，这些细胞如何通讯以确保正确的形态发生却并不明确。 完全了解中胚层和神经外胚层（NE，未来的神经管）组织形态发生。 通过会聚和延伸 (C&E)，当细胞插入时，身体会同时变窄和拉长 轴并将神经褶皱聚集在一起，以确保这些高度的神经管正确闭合。 保守的细胞运动可能导致神经管缺陷，影响全球许多怀孕。 保守的信号通路，在原肠胚形成过程中活跃，并且以其在 然而，对于 Nodal 在脊椎动物中的作用知之甚少。 C&E 形态发生独立于中胚层形成，特别是在 NE 中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，独立于其更广为人知的 为了检查节点在 NE 形态发生过程中的作用，我可以 使用离体斑马鱼胚盘外植体、幼稚胚胎簇独立分析 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。 外植体中节点信号的早期峰值促进中胚层延伸和规范。 我们实验室的初步数据表明，相对延迟的 Nodal 信号峰值会促进 NE- 特定的 C&E 形态发生与其在中胚层规范中的作用无关。 节点的时间调节调节 NE 特异性形态发生 根据我有希望的初步数据，我。 研究表明，Nodal 信号传导激活一种新颖的、时间调节的、NE 特异性转录程序 为了检验这个假设，我提出了 3 个独立于中胚层规范的驱动 C&E 形态发生的因素。 目标：目标 1 将研究颞节点信号动力学在 NE 特异性形态发生中的作用 光遗传学节点受体精确操纵胚胎外植体中的信号传导 在目标 2 中，我将恢复。 使用创新转基因系在节点缺陷斑马鱼胚胎的 NE 内特异地进行节点信号传导 确定Nodal是否可以在没有中胚层的情况下驱动体内NE延伸最后，在目标3中我将。 对临时调节的候选基因进行过度表达和敲低以确定它们是否 外植体和体内 NE 特异性延伸的驱动因素 该提案将定义基础知识。 关于 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。