Regenerative pathways in the avian cochlea

项目摘要/摘要 30多年来，人们已经知道，通常静止的鸟类听力器官中的支持细胞 基底乳头，可对感觉毛细胞死亡作出反应，伴随着S期的进入，有丝分裂，并生成 替换毛细胞。这里提出的工作利用了几个方法论上的进步， 全面、系统地清点氨基糖苷类药物诱导的基因表达变化 毛细胞死亡和反应中的支持细胞。从单个小区获得的多个时间点的导频数据 从鸡基底乳头感觉上皮分离的研究表明，激活一条新的通路与 蛋白水解酶激活受体-2是支持细胞和毛细胞进入S时相所必需的 再生。该项目对激活途径提出了一种特殊的假设，这将是明确的 并进行了彻底的评估。此外，新的再生途径的同源基因将是 在一种新的成年小鼠模型中评估长期毛细胞丢失。在这里，重点是S-阶段进入 氨基糖苷类药物致小鼠毛细胞丢失4周后，小鼠的椭圆囊和Corti器支持细胞。 最后，该项目将专注于通过重建新再生的毛细胞来表征 当新的毛细胞成熟时发生的时间转录变化。同时，还提议 将转录数据与原位观察相结合，如毛束形成、平面细胞变化 极性，突触连接的重建，以及电生理特征，如 机电转换和电气调谐。

Project Summary / Abstract It is known for more than 30 years that supporting cells in the normally quiescent avian hearing organ, the basilar papilla, can respond to sensory hair cell death with S-phase entry, mitotic division, and generation of replacement hair cells. The work proposed here utilizes several methodological advances for an unbiased, comprehensive, and systematic inventorying of changes in gene expression during aminoglycoside-induced hair cell death and in responding supporting cells. Pilot data obtained at multiple time points from single cells isolated from the chicken basilar papilla sensory epithelium revealed that activation of a novel pathway linked to protease-activated receptor-2, PAR2, is essential for S-phase entry of supporting cells and hair cell regeneration. The project puts forward a speci?c hypothesis for the activation pathway, which will be explicitly and thoroughly evaluated. Moreover, the identi?ed e?ector genes for the novel regeneration pathway will be assessed in a new adult mouse model for long-term hair cell loss. Here, the focus is on S-phase entry of mouse utricle and organ of Corti supporting cells four weeks after aminoglycoside-induced hair cell loss. Finally, the project will focus on the characterization of newly regenerated hair cells by reconstructing the temporal transcriptomic changes that happen when the new hair cells mature. In parallel, it is proposed to align transcriptomic data with in situ observations such as hair bundle formation, changes in planar cell polarity, reestablishment of synaptic connections, and electrophysiological features such as mechanoelectrical transduction and electrical tuning.