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，旨在提供对该系统如何发展的基线了解，并开始确定至少一些调节耳蜗神经支配的因素。 首先，我们开始使用几种抗体标记对螺旋神经节神经元的形成和分化进行描述性研究。初步结果表明，在毛细胞形成之前，神经元突起在发育中的耳蜗间，但特定接触的形成依赖于发育中的毛细胞的存在。 在第二系列实验中，我们使用了一种遗传方法，用黄色荧光蛋白标记了一小部分发育中的螺旋神经节神经元。这种方法将使我们能够将单个神经突起视作与毛细胞建立联系.在未来，我们将把这项技术与时间推移图像相结合，以观察特定连接是如何建立的 最后，作为第三种方法，我们研究了螺旋神经节神经突入耳蜗前必须通过的一组间充质细胞的影响。Pou3f4是一种已知的耳聋基因，仅在间充质中表达，对突变小鼠的分析表明，神经元路径发现存在缺陷，表明间充质细胞在耳蜗发育中发挥关键作用。

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.