Response of cochlear hair cells to pathological changes in the auditory system

项目摘要/摘要 老鼠的耳蜗只有800个内毛细胞，外毛细胞的数量大约是内毛细胞的三倍。这么低 细胞的数量阻碍了内耳细胞分子生物学研究的进展。 单个毛细胞基因表达谱的使用有可能将这一缺点转变为主要的 优势，因为它允许通过产生高分辨率定量基因来对器官进行过度采样 Corti器官的数千个内毛细胞和外毛细胞的表达图谱，这是本研究的第一个目标 批准申请。预计这些基于单细胞RNA-Seq数据的图谱几乎不会丢失 例如，与视网膜等其他感觉系统进行比较时的信息，其中对 几千个感光细胞将占感觉细胞总数的0.05%。预计 这些图谱将揭示基因表达的梯度如何影响内毛和外毛的功能紧张性。 细胞。此外，生成的地图将作为识别耳蜗毛的明显变化的基线 噪声诱导细胞暂时性阈值漂移。在这里，预计分析将揭示功能 共同调控的发束基因模块以及候选基因调控网络 噪音引起的听力损失。第二系列实验旨在通过以下方式确定分子机制 哪种非创伤性声音暴露可暂时降低永久性噪声诱发阈值的易感性 换档。这项研究有可能阐明与噪音易感性有关的基因和机制。 最后，建议在分子水平上研究内、外毛细胞的代偿性变化。 对诸如缺乏功能性传入或传出的耳蜗性整合的持续变化作出反应 外毛细胞与被膜之间有神经支配或缺乏联系。除了识别 以共调控基因群为例，参与耳蜗扩增，预计这项研究将 揭示毛细胞如何受到不会立即引发毛细胞丢失的病理情况的影响。

Project Summary / Abstract The mouse cochlea harbors only 800 inner hair cells and about three times as many outer hair cells. This low number of cells has hampered progress specifically in the study of the molecular biology of inner ear cells. The use of single hair cell gene expression profiling has the potential to turn this disadvantage into a major advantage because it allows for oversampling the organ by generating high resolution quantitative gene expression maps for thousands of inner and outer hair cells of the organ of Corti, which is the first Aim of this grant application. It is anticipated that these maps, based on single cell RNA-Seq data will miss little information when compared for example with other sensory systems such as the retina, where analysis of a few thousand photoreceptor cells would represent <0.05% of the sensory cell population. It is anticipated that the maps will reveal how gradients of gene expression contribute to functional tonotopy in inner and outer hair cells. Moreover, the generated maps will serve as base line for identifying distinct changes in cochlear hair cells after noise-induced temporary threshold shift. Here, it is anticipated that the analysis will reveal functional modules of co-regulated hair bundle genes as well as candidate gene regulatory networks for susceptibility to noise-induced hearing loss. A second series of experiments aims to identify the molecular mechanisms by which non-traumatic sound exposure temporarily reduces susceptibility for permanent noise induced threshold shift. This research has the potential of elucidating genes and mechanisms involved in susceptibility to noise. Finally, it is proposed to investigate at the molecular level compensatory changes in inner and outer hair cells in response to sustained changes in cochlear integration such as lack of functional afferent or efferent innervation or lack of connection between outer hair cells and the tectorial membrane. Beside identification of co-regulated gene groups for example involved in cochlear amplification, it is expected that this research will reveal how hair cells are affected by pathological situations that do not trigger immediate hair cell loss.