Site-specific interactions of neurotrophin-3 and fibroblast growth factor (FGF2) in the embryonic development of the mouse cochlear nucleus
Site-specific interactions of neurotrophin-3 and fibroblast growth factor (FGF2) in the embryonic development of the mouse cochlear nucleus
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DOI：
10.1002/neu.20264
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发表时间：
2006-08-01
期刊：
影响因子：
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通讯作者：
Morest, D. Kent
中科院分区：
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作者：
Hossain, Waheeda A.;D'Sa, Chrystal;Morest, D. Kent
神经营养因子和成纤维细胞生长因子2有助于耳蜗核的形成，但它们在耳蜗核发育中的作用尚不清楚。这些因素在耳蜗核和耳蜗核中的作用可能不同，它们可能会相互影响对方的发育。在正常的形态发生序列中，分析这些因素对细胞结构的影响是很重要的。本研究采用免疫组织化学方法对因子进行原位定位，并对其在体外模型中的作用假说进行了验证。特异性抗体染色显示，NT3受体TrkC存在于胚胎出生前至出生后的神经前体细胞中。NT3在迁移过程中(E13-E15)出现在前体细胞中，出生时消失。TrkC和NT3存在于相同的结构中，包括生长中的轴突、终末和它们的突触靶标。因此，NT3在TrkC定义的窗口内跟踪迁移路线和形态发生序列。在体外，从E11胚胎中移植出耳蜗核原基。将培养物分成不同的组，分别用固定的培养基加或不加FGF2、BDNF和NT3的补充剂，单独或混合饲喂7天。当神经母细胞迁移分化时，免疫组织化学染色定位NT3和TrkC在形态发生序列中，溴脱氧尿嘧啶核苷用于增殖，突触囊泡蛋白用于突触发生。通过时间推移成像和定量测量，结果支持FGF2促进增殖和迁移的假设。NT3与成纤维细胞生长因子2和脑源性神经营养因子相互作用，促进轴突生长、丛生和突触形成。因子和受体定位于发生关键变化的结构部位。(C)2006年威利期刊公司。
Neurotrophins and FGF2 contribute to formation of the cochlea, but their roles in cochlear nucleus development are unknown. The effects of these factors may differ in the cochlea and cochlear nucleus, which may influence each other's development. It is important to analyze the effects of these factors on cellular structures at well-defined steps in the normal morphogenetic sequence. The present study used immunohistochemistry to localize factors in situ and to test hypotheses about their roles in an in vitro model. Specific antibody staining revealed that TrkC, the NT3 receptor, is present in neural precursors prior to embryonic day Ell until after birth. NT3 appeared in precursor cells during migration (E13-E15) and disappeared at birth. TrkC and NT3 occurred in the same structures, including growing axons, terminals, and their synaptic targets. Thus, NT3 tracks the migration routes and the morphogenetic sequences within a window defined by TrkC. In vitro, the cochlear nucleus anlage was explanted from Ell embryos. Cultures were divided into groups fed with defined medium, with or without FGF2, BDNF, and NT3 supplements, alone or in combinations, for 7 days. When neuroblasts migrated and differentiated, immunostaining was used for locating NT3 and TrkC in the morphogenetic sequence, bromodeoxyuridine for proliferation, and synaptic vesicle protein for synaptogenesis. By time-lapse imaging and quantitative measures, the results support the hypothesis that FGF2 promotes proliferation and migration. NT3 interacts with FGF2 and BDNF to promote neurite outgrowth, fasciculation, and synapse formation. Factors and receptors localize to the structural sites undergoing critical changes. (c) 2006 Wiley Periodicals, Inc.