Functional analysis of early vagal neural crest and ENS development

描述(申请人提供)：肠神经系统(ENS)是周围神经系统中最复杂和最大的部分。ENS由一系列相互连接的神经元和神经胶质细胞组成，它们控制肠道运动并调节肠壁内的血液流动。在发育过程中，ENS产生于迷走神经脊细胞，这些细胞在后脑尾侧水平从神经管中迁出。到达前肠后，迷走神经来源的肠神经脊细胞沿着发育中的肠道向尾部迁移，并分化为 肠神经细胞和神经胶质细胞类型。在先天性异常中，如先天性巨结肠，肠道远端缺乏肠神经元或神经胶质细胞，导致巨结肠和慢性便秘。目前，许多研究都集中在肠神经脊细胞迁移的功能分析上。 ENS发育后期的肠道，调节其迁移的分子机制，以及早期迷走神经和肠神经脊细胞的定位，目前还知之甚少。这项计划中的实验将利用斑马鱼和鸡的胚胎，以加强我们对迷走神经脊和ENS发育早期调控机制的理解。鸡和斑马鱼的胚胎都是在外部发育的，因此很容易进行实验操作和观察。此外，斑马鱼胚胎在发育过程中是透明的，因此可以对神经脊细胞迁移进行高分辨率分析。本研究的具体目的是：1.研究Meis3在斑马鱼肠神经脊发育中的作用；2.阐明HOXB5在迷走神经和肠神经脊发育中的作用和调控。这些实验的结果将显著提高我们对肠神经嵴细胞迁移和命运指定的基本理解，从而提供一个 为上游翻译研究工作奠定坚实的基础。

DESCRIPTION (provided by applicant): The enteric nervous system (ENS) is the most complex and largest portion of the peripheral nervous system. The ENS is comprised of a complex series of interconnected neurons and glia that control intestinal motility and regulate blood flow within the gut wall. During development, ENS arises from vagal neural crest cells that emigrate from the neural tube at caudal hindbrain levels. Upon reaching the foregut, the vagal-derived enteric neural crest cells migrate caudally along the developing gut and differentiate into enteric neurons and glial cell types. Abnormalities in migration to or along the gut or along resul in birth anomalies like Hirschsprung's Disease, in which the distal portion of the intestine is devoid of enteric neurons or glia, resulting in megacolon and chronic constipation. While much research attention has focused on the functional analysis of enteric neural crest cell migration in the gut during later phases of ENS development, the molecular mechanisms that regulate their migration and the designation of early vagal and enteric neural crest cell identity is poorly understood. The experiments in this proposal will utilize zebrafish and chicken embryos in order to enhance our understanding of the mechanisms that regulate early phases of vagal neural crest and ENS development. Both chicken and zebrafish embryos develop externally, allowing for easy experimental manipulation and observation. Furthermore, zebrafish embryos are transparent during development allowing for high-resolution analysis of neural crest cell migration. The specific aims are to 1. Investigate the role of Meis3 in development of the zebrafish enteric neural crest, and 2. Elucidate the role and regulation of Hoxb5 in vagal and enteric neural crest development. The results of these experiments will significantly improve our basic understanding of enteric neural crest cell migration and fate specification, thus providing a solid foundation on which to base upstream translational research endeavors.