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: 10409742
• 负责人: Austen Anne Sitko
• 金额: $ 7.39万
• 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/10409742
• 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; Gene Expression Profile; 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; cochlear development; 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.

项目摘要 橄榄石神经元（OCNS）居住在听觉脑干中，并向耳蜗投射出来 除了螺旋神经神经元（SGN）的传入电路之外 耳蜗。 OCN保护耳蜗免受噪声损害和调节声输入，并在 听觉电路的传入和传出组件对于正确的听觉功能至关重要。 OCN是 由内侧橄榄石神经元（MOC）和外侧橄榄石神经元（LOC）组成，该神经元（LOC）支配 外毛细胞（OHC）和SGN。 MOC轴突在LOC前到达耳蜗， 在SGN传入的重要时期，瞬时支配内毛细胞（IHC） 电路。因此，MOC在影响SGN的发展和后来派生的主要位置 OCN轴突。 到目前为止，缺乏遗传进入MOC和LOC的障碍阻碍了识别细胞 - 细胞相互作用的进展 在早期人工耳蜗开发过程中，OCN和SGN之间，留下了许多关于如何中心的开放问题 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 遗传工具选择性标记和扰动OCN，以解决早期OCN的假设 轴突与SGNS和IHC相互作用，以塑造耳蜗电路的发展。 AIM 1将尽早使用 诱导牵头小鼠重组以稀疏和有选择地标记第一个进入该轴突 耳蜗。将分析标记的OCN纤维和突触，以提供关键交互的详细说明 在MOC轴突和SGNS和IHC之间。 AIM 2将首先转录介绍胚胎MOC和LOC 使用单细胞RNA测序来识别可能引导OCN 发展。最后，将在Epha4和Ephrin-A5突变体中评估传出/传入的布线 关于传出的探路机制以及epha4/ephrin-a5如何介导的多个方面 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 在建立功能性听觉电路的耳蜗中的OCN轴突和其他细胞之间。 研究培训计划将在听觉系统，分子遗传学上提供广泛的培训 方法，定量图像分析和基本生物信息学。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介绍研究 会议，部门会谈和会议。根据本计划发展的技能将为 听觉神经生物学领域的独立研究职业，研究Axon-Axon互动的作用 在听觉电路的开发中。