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节的事件，它们将单个细胞构建为复杂的生物体。一个 早期胚胎发育中的关键里程碑是胃，当身体计划首先由行为塑造时 成千上万个单个细胞。但是，这些细胞如何通信以确保正确形态发生不是 完全理解。中胚层和神经外胚层（NE，未来神经元管）组织形态发生驱动 通过收敛和延伸（C＆E），当细胞插入到同时狭窄并拉长身体时 轴并将神经折叠夹融合在一起，以确保正确的神经管闭合。这些高度破坏 保守的细胞运动会导致神经管缺陷，影响全球许多妊娠。 nodal是一个 构成良好的信号通路，在过度期间活跃，并且以其在其中所扮演的作用而闻名 脊椎动物中的中胚层和内胚层规格。但是，关于节点在 C＆E形态发生独立于中胚层形成，特别是在NE中。通过使用斑马鱼前体和 在体内模型中，我将研究节点在形态发生中的作用，而不是其较知名的 在组织规范期间的功能。为了检查淋巴结潜在的NE形态发生的作用，我可以 使用离体斑马鱼胚层外植体独立分析NE扩展 形成所有三个细菌层并响应外源性淋巴结信号转导的细胞。 Epplants中淋巴结信号的早期峰促进了中胚层的扩展和规范。然而， 我们实验室的初步数据表明，淋巴结信号的相对延迟峰促进了NE- 特定的C＆E形态发生与其在中胚层规范中的作用无关。这表明 淋巴结调节NE特异性形态发生的临时调节。根据我的诺言初步数据，我 假设节点信号传导激活了一种新型的，暂时调节的，NE的转录程序 这驱动C＆E形态发生独立于中胚层规范。为了检验这一假设，我提出了3 目的：AIM 1将研究临时淋巴结信号传导动力学在NE特异性形态发生中的作用 光遗传学淋巴结受体，以精确操纵胚胎外植体中的信号传导。在AIM 2中，我将还原 淋巴结信号传导是在Nodal缺乏斑马鱼胚胎中使用创新的转基因线 确定淋巴结是否可以在没有中胚层的情况下驱动体内延伸。最后，在目标3中，我会 对表达和暂时调节的候选基因进行敲除以确定它们是否是 NE特异性扩展的驱动因素和体内。该建议将定义基本知识 关于节点在NE特异性形态发生中的主要作用，其中可能有助于神经管 缺陷患病率和严重性。