Pomeranz H D, Sherman D L, Smalheiser N R, Tennyson V M, Gershon M D
Department of Anatomy and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, New York 10032.
J Comp Neurol. 1991 Nov 22;313(4):625-42. doi: 10.1002/cne.903130408.
In order to give rise to the enteric nervous system (ENS), cells migrating from the neural crest must find the bowel and cease migrating at appropriate locations within the gut. Previous studies of the development of the ENS in a mutant mouse have led to the hypothesis that laminin in the enteric mesenchyme may act as a signal to crest-derived cells to cease migrating and extend neurites (or glial processes). Implied in this hypothesis is the idea that crest-derived cells, as a prelude to their participation in ganglion formation, acquire a neurally related laminin receptor, which they do not express at pre-enteric stages of migration. As a partial test of this hypothesis, single and double label immunocytochemistry at light and electron microscopic (EM) levels were used to study the expression of cell surface laminin binding proteins by crest-derived cells in the process of migrating to or within the developing chick gut. Two antibodies (called 3070 and alpha-110) raised against neuronal cell surface laminin binding proteins were employed for this purpose. Laminin binding protein immunoreactivity was found to be expressed within the bowel and ganglion of Remak by a subset of crest-derived cells (identified immunocytochemically with NC-1/HNK-1 antibodies) and by all of those developing as neurons (identified immunocytochemically with antibodies to neurofilament-associated proteins). Laminin binding protein immunoreactivity was also found to be expressed in fixed neural structures elsewhere in the embryos, including cranial and spinal roots, nerves, and ganglia. In contrast, laminin binding protein immunoreactivity was not expressed by migrating crest-derived cells in the vicinity of the vagal or sacral regions of the neuraxis (from which the precursors of the ENS take origin); nor was it expressed by juxta-pharyngeal vagal crest-derived cells migrating to the foregut through the caudal branchial arches or by the caudal stream of sacral crest-derived cells approaching the hindgut. EM immunocytochemistry confirmed that laminin binding protein immunoreactivity in the bowel was located on the surfaces of crest-derived cells, and was exhibited both by those cells that could only be distinguished from their neighbors by their NC-1/HNK-1 immunoreactivity and by cells developing as neurons or glia. EM immunocytochemistry also revealed that the surfaces of crest-derived cells migrating through the enteric mesenchyme were contacted by many small osmiophilic "puffs" of laminin-immunoreactive extracellular material. These puffs coincided in location with membrane sites that expressed the immunoreactivity of the laminin binding protein. These observations are consistent with the hypothesis that laminin plays a role in the formation of enteric ganglia.
为了形成肠神经系统（ENS），从神经嵴迁移而来的细胞必须找到肠道，并在肠道内的适当位置停止迁移。先前对突变小鼠中ENS发育的研究提出了一种假说，即肠间充质中的层粘连蛋白可能作为一种信号，促使源自神经嵴的细胞停止迁移并延伸神经突（或神经胶质突起）。该假说暗示，源自神经嵴的细胞在参与神经节形成之前，会获得一种与神经相关的层粘连蛋白受体，而在进入肠道前的迁移阶段它们并不表达这种受体。作为对该假说的部分验证，利用光镜和电镜（EM）水平的单标和双标免疫细胞化学技术，研究了在迁移至发育中的鸡肠道或在肠道内的过程中，源自神经嵴的细胞表面层粘连蛋白结合蛋白的表达情况。为此使用了两种针对神经元细胞表面层粘连蛋白结合蛋白产生的抗体（分别称为3070和α - 110）。发现层粘连蛋白结合蛋白免疫反应性在Remak神经节和肠道内由一部分源自神经嵴的细胞（用NC - 1/HNK - 1抗体免疫细胞化学鉴定）以及所有发育为神经元的细胞（用神经丝相关蛋白抗体免疫细胞化学鉴定）表达。在胚胎其他部位的固定神经结构中也发现了层粘连蛋白结合蛋白免疫反应性的表达，包括颅神经和脊神经根、神经以及神经节。相比之下，在神经轴的迷走或骶区附近迁移的源自神经嵴的细胞（ENS的前体由此起源）不表达层粘连蛋白结合蛋白免疫反应性；通过尾鳃弓迁移至前肠的近咽迷走神经嵴衍生细胞或接近后肠的骶神经嵴衍生细胞的尾流也不表达。电镜免疫细胞化学证实，肠道中层粘连蛋白结合蛋白免疫反应性位于源自神经嵴的细胞表面，那些只能通过其NC - 1/HNK - 1免疫反应性与相邻细胞区分开来的细胞以及发育为神经元或神经胶质的细胞均有表达。电镜免疫细胞化学还显示，穿过肠间充质迁移的源自神经嵴的细胞表面与许多小的嗜锇性“泡状物”接触，这些泡状物为层粘连蛋白免疫反应性细胞外物质。这些泡状物的位置与表达层粘连蛋白结合蛋白免疫反应性的膜位点一致。这些观察结果与层粘连蛋白在肠神经节形成中起作用的假说相符。
