Young H M, Turner K N, Bergner A J
Department of Anatomy and Cell Biology, University of Melbourne, 3010, Melbourne, Victoria, Australia.
Cell Tissue Res. 2005 Apr;320(1):1-9. doi: 10.1007/s00441-004-1057-5. Epub 2005 Feb 16.
Neural crest cells that originate in the caudal hindbrain migrate into and along the developing gastrointestinal tract to form the enteric nervous system. While they are migrating, neural-crest-derived cells are also proliferating. Previous studies have shown that the expression of glial-derived neurotrophic factor (GDNF) and endothelin-3 is highest in the embryonic caecum, and that GDNF alone or in combination with endothelin-3 promotes the proliferation of enteric neural-crest-derived cells in vitro. However, whether neural proliferative zones, like those in the central nervous system, are found along the developing gut is unknown. We used a fluorescent nucleic acid stain to identify dividing cells or BrdU labelling (2 h after administration of BrdU to the mother), combined with antibodies specific to neural crest cells to determine the percentage of proliferating crest-derived cells in various gut regions of embryonic day 11.5 (E11.5) and E12.5 mice. The rate of proliferation of crest-derived cells did not vary significantly in different regions of the gut (including the caecum) or at different distances from the migratory wavefront of vagal crest-derived cells. The phenotype of mitotic enteric crest-derived cells was also examined. Cells expressing the pan-neuronal markers, neurofilament-M and Hu, or the glial marker, S100b, were observed undergoing mitosis. However, no evidence was found for proliferation of cells expressing neuron-type-specific markers, such as nitric oxide synthase (at E12.5) or calcitonin gene-related peptide (at E18.5). Thus, for enteric neurons, exit from the cell cycle appears to occur after the expression of pan-neuronal proteins but prior to the expression of markers of terminally differentiated neurons.
起源于后脑尾部的神经嵴细胞迁移至发育中的胃肠道并沿着其迁移，以形成肠神经系统。在迁移过程中，神经嵴衍生细胞也在增殖。先前的研究表明，胶质细胞源性神经营养因子（GDNF）和内皮素-3在胚胎盲肠中的表达最高，并且单独的GDNF或与内皮素-3联合使用可在体外促进肠神经嵴衍生细胞的增殖。然而，沿发育中的肠道是否存在像中枢神经系统中那样的神经增殖区尚不清楚。我们使用荧光核酸染料来识别分裂细胞或进行BrdU标记（给母体注射BrdU后2小时），并结合针对神经嵴细胞的特异性抗体，以确定胚胎第11.5天（E11.5）和E12.5天小鼠不同肠道区域中增殖的嵴衍生细胞的百分比。嵴衍生细胞的增殖率在肠道的不同区域（包括盲肠）或距迷走神经嵴衍生细胞迁移波前不同距离处并无显著差异。我们还检查了有丝分裂的肠嵴衍生细胞的表型。观察到表达泛神经元标志物神经丝蛋白-M和Hu或胶质标志物S100b的细胞正在进行有丝分裂。然而，未发现表达神经元类型特异性标志物（如一氧化氮合酶（在E12.5时）或降钙素基因相关肽（在E18.5时））的细胞增殖的证据。因此，对于肠神经元而言，细胞周期退出似乎发生在泛神经元蛋白表达之后但在终末分化神经元标志物表达之前。
