Spiral ganglion cell development and patterning in the mammalian cochlea

在这个项目的第一年，我们启动了三个子项目，旨在提供一个基线的了解如何这个系统的发展，以及开始，以确定至少一些因素，介导耳蜗内的神经支配。 首先，我们开始使用几种抗体标记的螺旋神经节神经元的形成和分化的描述性研究。 初步结果表明，在毛细胞形成之前，发育中的耳蜗中存在神经元过程，但特定接触的形成取决于发育中的毛细胞的存在。 在第二个系列的实验中，我们使用了一种遗传方法，用黄色荧光蛋白标记一小部分正在发育的螺旋神经节神经元。 这种方法将使我们能够可视化单个神经突与毛细胞建立连接。 将来，我们将联合收割机与延时成像技术相结合，观察特定的连接是如何建立的 最后，作为第三种方法，我们研究了螺旋神经节神经突在进入耳蜗之前必须通过的间充质细胞群体的影响。 对Pou3f4（一种仅在间充质中表达的已知耳聋基因）突变小鼠的分析表明，神经元寻路存在缺陷，这表明间充质细胞在耳蜗发育中起着关键作用。

In the first year of this project we initiated three sub-projects designed to provide a baseline understanding of how this system develops as well as to begin to identify at least some of the factors that mediate innervation within the cochlea. First, we began a descriptive study of the formation and differenation of spiral ganglion neurons using several antibody markers. Preliminary results indicate neuronal processes inter the developing cochlea prior to hair cell formation, but that the formation of specific contacts is dependent on the presence of developing hair cells. In a second series of experiments we used an genetic approach to label a small subset of developing spiral gangion neurons with yellow fluorescent protein. This approach will allow us to visualize single neurites as the establish connections with hair cells. In the future we will combine this technique with time lapse imagery to observe how specific connections are established Finally, as a third approach we have examined the effects of a population of mesenchymal cells that spiral ganglion neurites must pass through prior to entering the cochlea. Analysis of mice with a mutation in Pou3f4, a known deafness gene expressed exclusively in mesenchyme, indicates defects in neuronal pathfinding, indicating that mesenchymal cells play a key role in cochlear development.