Morphological and Molecular Development of Efferent Innervation of the Cochlea

耳蜗传出神经支配的形态和分子发育

• 批准号: 10066467
• 负责人: Austen Anne Sitko
• 金额: $ 6.74万
• 依托单位: HARVARD MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-06-01 至 2023-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10066467
• 关键词: Acoustic Trauma; Acoustics; Address; Affect; Afferent Neurons; Auditory; Auditory system; Axon; Binding; Bioinformatics; Brain Stem; Candidate Disease Gene; Cell Communication; Cell Nucleus; Cells; Cochlea; Cochlear nucleus; Communities; Complex; Data; Data Analyses; Development; Developmental Process; Embryo; Ensure; Environment; Ephrin-A5; Ephrins; Feedback; Fiber; Genetic; Genetic Recombination; Genetic Transcription; Group Meetings; Hearing; Image Analysis; Inner Hair Cells; Knowledge; Label; Labyrinth; Lateral; Light; Medial; Mediating; Molecular; Molecular Genetics; Morphology; Motor Neurons; Mus; Mutant Strains Mice; Neurobiology; Neurons; Noise; Outer Hair Cells; Pattern; Peripheral; Peripheral Nervous System; Play; Positioning Attribute; Process; Research; Research Training; Rodent; Role; Series; Shapes; Synapses; Testing; Time; Training; axon growth; axon guidance; axonal pathfinding; base; career; cell type; cholinergic; conditional knockout; differential expression; genetic approach; insight; lateral superior olive; mutant; nerve supply; neurodevelopment; neuron development; neuronal cell body; postnatal; quantitative imaging; single-cell RNA sequencing; skills; spiral ganglion; student mentoring; symposium; tool; trapezoid body

Project Summary Olivocochlear neurons (OCNs) reside in the auditory brainstem and project to the cochlea, providing efferent innervation in addition to the afferent circuitry of the spiral ganglion neurons (SGNs), housed within the cochlea. OCNs protect the cochlea from noise damage and modulate acoustic input, and alignment between the afferent and efferent components of auditory circuitry is crucial for proper auditory functioning. OCNs are composed of medial olivocochlear neurons (MOCs) and lateral olivocochlear neurons (LOCs), which innervate the outer hair cells (OHCs) and SGNs, respectively. MOC axons arrive in the cochlea before LOCs and transiently innervate inner hair cells (IHCs) during an important period of development of the SGN afferent circuitry. MOCs are therefore in a prime position to influence both the development of SGNs and later-arriving OCN axons. A lack of genetic access to MOCs and LOCs has so far hindered progress in identifying the cell-cell interactions between OCNs and SGNs during early cochlear development, leaving many open questions about how central and peripheral components of the auditory system align. This research training plan will use newly identified genetic tools to selectively label and perturb OCNs in order to address the hypothesis that early arriving OCN axons interact with SGNs and IHCs to shape the development of cochlear circuitry. Aim 1 will use early induction of recombination in RetCreER mice to sparsely and selectively label the first MOC axons to enter the cochlea. Labeled OCN fibers and synapses will be analyzed to provide a detailed account of key interactions between MOC axons and SGNs and IHCs. Aim 2 will first transcriptionally profile embryonic MOCs and LOCs using single-cell RNA-sequencing to identify Ephs, ephrins, and other molecules that may guide OCN development. Finally, efferent/afferent wiring will be assessed in EphA4 and ephrin-A5 mutants to shed light on efferent pathfinding mechanisms and how EphA4/ephrin-A5 interactions mediate multiple aspects of cochlear circuitry. Results from these studies will reveal important morphological and molecular interactions between OCN axons and other cells in the cochlea that establish a functioning auditory circuit. The research training plan will provide extensive training in the auditory system, molecular genetics approaches, quantitative image analysis, and basic bioinformatics. Additionally, the training plan will offer professional development opportunities, including mentoring students and presenting research at small group meetings, departmental talks, and conferences. The skills developed under this plan will pave the way for an independent research career in the field of auditory neurobiology, studying the role of axon-axon interactions in the development of auditory circuitry.

项目概要 橄榄耳蜗神经元 (OCN) 驻留在听觉脑干中并投射到耳蜗，提供传出信号 除了位于螺旋神经节神经元 (SGN) 内的传入回路外，还有神经支配 耳蜗。 OCN 保护耳蜗免受噪声损害并调节声输入以及耳蜗之间的对齐 听觉电路的传入和传出组件对于正常的听觉功能至关重要。 OCN 是 由内侧橄榄耳蜗神经元 (MOC) 和外侧橄榄耳蜗神经元 (LOC) 组成， 分别为外毛细胞 (OHC) 和 SGN。 MOC 轴突先于 LOC 到达耳蜗， 在 SGN 传入神经发育的重要时期短暂地支配内毛细胞 (IHC) 电路。因此，MOC 处于影响 SGN 和后来出现的发展的首要位置。 OCN 轴突。 迄今为止，缺乏 MOC 和 LOC 的遗传途径阻碍了识别细胞间相互作用的进展 在早期耳蜗发育过程中，OCN 和 SGN 之间存在着差异，留下了许多悬而未决的问题： 和听觉系统的外围组件对齐。该研究培训计划将使用新确定的 遗传工具选择性地标记和扰乱 OCN，以解决早期到达的 OCN 的假设 轴突与 SGN 和 IHC 相互作用，塑造耳蜗回路的发育。目标1将尽早使用 在 RetCreER 小鼠中诱导重组，以稀疏且选择性地标记第一个进入的 MOC 轴突 耳蜗。将分析标记的 OCN 纤维和突触，以提供关键相互作用的详细说明 MOC 轴突与 SGN 和 IHC 之间。目标 2 将首先对胚胎 MOC 和 LOC 进行转录分析 使用单细胞 RNA 测序来识别 Ephs、ephrins 和其他可能指导 OCN 的分子 发展。最后，将评估 EphA4 和 ephrin-A5 突变体的传出/传入线路以揭示真相 传出寻路机制以及 EphA4/ephrin-A5 相互作用如何介导多个方面 耳蜗电路。这些研究的结果将揭示重要的形态和分子相互作用 OCN 轴突和耳蜗中其他细胞之间建立功能性听觉回路。 研究培训计划将提供听觉系统、分子遗传学方面的广泛培训 方法、定量图像分析和基础生物信息学。此外，培训计划将提供 专业发展机会，包括指导学生和在小组中展示研究成果 会议、部门会谈和会议。根据该计划开发的技能将为 听觉神经生物学领域的独立研究生涯，研究轴突-轴突相互作用的作用 听觉电路的发展。