Molecular Interactions During Neural Crest Formation

描述（由申请人提供）：本项目的长期目标是促进我们对控制神经嵴发育的细胞和分子机制的理解。神经嵴细胞是脊椎动物特有的，在发育早期出现，广泛迁移并分化成几种衍生物，包括：颅面成分（肌肉和软骨等），外周神经系统和皮肤的黑色素细胞。神经嵴发育和体内平衡的缺陷导致称为“神经损伤”的人类病理学，包括唇/腭裂、Waardenburg综合征和黑素瘤等。推进我们对神经嵴细胞生物学的理解是帮助诊断和治疗方法的基础。该项目研究神经嵴形成的早期阶段，并侧重于信号通路的贡献。这项工作集中在两个模型-鸟类胚胎和一种基于人类胚胎干细胞的人类神经嵴发育的新模型。在鸡中，我们利用囊胚胚胎，而在人类干细胞模型中，我们解决了分化的最早时间点。在这两种模型中，Wnt和FGF信号通路的作用将特别关注转录效应子。目的1是为了阐明不同的FGF信号分支在囊胚和原肠胚阶段的具体贡献，并建立不同的反应和Pea 3亚家族的转录效应。目的2剖析了主导的经典和替代的非经典Wnt通路的贡献。这里的重点将针对转录因子Tcf和Lef。目的3：建立一个有效的人胚胎干细胞神经嵴发育模型，并建立这两条信号通路（FGF、Wnt）对人神经嵴发育的作用机制。这项工作将阐明高等脊椎动物（鸟类和哺乳动物）神经嵴形成的基本原理，并将振兴人类神经嵴研究。

DESCRIPTION (provided by applicant): The long term goal of this project is to advance our understanding of the cellular and molecular mechanisms that control neural crest development. Neural crest cells are vertebrate-specific, appear early in development, migrate extensively and differentiate into several derivatives, including: craniofacial components (muscle and cartilage amongst others), peripheral nervous system and melanocytes of the skin. Defects in neural crest development and homeostasis result in human pathologies known as "neurocristopathies" that include cleft lip/palate, Waardenburg syndrome, and melanoma, amongst others. Advancing our understanding of the biology of neural crest cells is fundamental to aid in diagnostic and therapeutic approaches. This project investigates early stages of neural crest formation, and focuses on the contributions made by signaling pathways. This work centers in two models - the avian embryo and a novel model of human neural crest development based on human embryonic stem cells. In the chick we utilize blastula embryos, while in the human stem cell model we address the earliest time points of differentiation. In both models, the role of Wnt and FGF signaling pathways will be scrutinized with particular focus on transcriptional effectors. Aim 1 is directed to elucidate the specific contributions made by distinct FGF-signaling branches during blastula and gastrula stages, and to establish differential responses and transcriptional effectors of the Pea3 sub-family. Aim 2 dissects the contributions made by the dominant canonical and alternative non- canonical Wnt pathways. Here emphasis will be directed to the transcriptional factors Tcf and Lef. Aim 3 will validate and eficcient model of human NC development, and establish the contributions made by these two signaling pathways (FGF, Wnt) to human neural crest development using an efficient and robust model based in human embryonic stem cells. This work will illuminate fundamental principles of neural crest formation in higher vertebrates (birds and mammals), and will invigorate human neural crest studies.