Le Douarin N M
Institut d'Embryologie Cellulaire et Moléculaire du CNRS, Nogent-sur-Marne, France.
Ann Endocrinol (Paris). 1988;49(4-5):256-69.
The peripheral nervous system (PNS) is derived from a transitory embryonic structure, the neural crest with an additional contribution of the cephalic ectodermal placodes to the sensory ganglia of certain cranial nerves. In vivo grafting experiments, taking advantage of the quail/chick marker system, allowed the fate map of the neural crest to be constructed and the precise level of origin along the neuraxis of the component cells of PNS ganglia to be defined. It appeared that the neural crest is regionalized in different areas from which a limited number of phenotypes arise. However, if the position of neural crest fragments is experimentally changed prior to the onset of migration, it turns out that virtually all the cell types represented in PNS ganglia can arise from any level of the neural crest, provided it is transplanted into the appropriate level of the neuraxis. This means that the microenvironment into which the neural crest cells migrate plays a critical role in directing their differentiation. Further in vivo studies along with in vitro clonal analysis of neural crest developmental potencies revealed that, during the migratory phase, the crest cells are already highly heterogeneous in their state of commitment. When they reach the sites of gangliogenesis, they exhibit different requirements for growth and differentiation. Our current studies are aimed at identifying the factors that, in spinal and sympathetic ganglia respectively, trigger the differentiation of sensory and adrenergic sympathetic neurons. The brain-derived neurotrophic factor (BDNF) and insulin (and/or IGF1) have been shown to play a role in these processes.
外周神经系统（PNS）起源于一个短暂的胚胎结构——神经嵴，某些颅神经的感觉神经节还额外有头部外胚层基板的贡献。利用鹌鹑/鸡标记系统进行的体内移植实验，使得构建神经嵴的命运图谱以及确定PNS神经节组成细胞沿神经轴的精确起源水平成为可能。结果表明，神经嵴在不同区域呈现区域化，由此产生数量有限的表型。然而，如果在迁移开始前通过实验改变神经嵴片段的位置，结果发现，只要将其移植到神经轴的适当水平，PNS神经节中几乎所有的细胞类型都可以从神经嵴的任何水平产生。这意味着神经嵴细胞迁移进入的微环境在指导其分化过程中起着关键作用。进一步的体内研究以及对神经嵴发育潜能的体外克隆分析表明，在迁移阶段，嵴细胞在其分化状态上已经高度异质。当它们到达神经节形成部位时，对生长和分化表现出不同的需求。我们目前的研究旨在分别确定在脊髓和交感神经节中触发感觉神经元和肾上腺素能交感神经元分化的因素。脑源性神经营养因子（BDNF）和胰岛素（和/或IGF1）已被证明在这些过程中发挥作用。
