Molecular mechanisms of cochlear hair bundle mechanics

耳蜗毛束力学的分子机制

• 批准号: 10393598
• 负责人: Anthony Wei Peng
• 金额: $ 44.48万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-06-07 至 2023-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10393598
• 关键词: ATP phosphohydrolase; Acute; Apical; Auditory; Auditory system; Automobile Driving; Bilateral Hearing Loss; Biological Assay; Biology; CRISPR/Cas technology; Calcium; Cells; Cochlea; Complex; Consumption; Coupled; Cytoskeleton; DNA Sequence Alteration; Data; Defect; Development; Discrimination; Disease; Electrophysiology (science); Frequencies; Generations; Genes; Genetic study; Hair; Hair Cells; Hearing; Human; Image; Investigation; Knowledge; Lead; Link; Lipids; MYO7A gene; Mammals; Mechanics; Mechanoreceptor Cell; Mediating; Membrane Lipids; Modeling; Molecular; Monitor; Morphology; Motor; Mutation; Myosin ATPase; Ouabain; Peptide Hydrolases; Persons; Pharmacology; Positioning Attribute; Prevention; Process; Property; Protein Isoforms; Proteins; Rana; Reporting; Role; Sensory; Sensory Hair; Side; Signal Transduction; Site; Speed; Stimulus; Sulfate; System; Technology; Testing; Therapeutic; Translating; Turtles; Vanadates; Work; analog; auditory processing; base; cell motility; deafness; experience; experimental study; extracellular; hearing impairment; hearing restoration; in vivo; inhibitor; mechanotransduction; mouse model; myosin XVA; neuronal cell body; new technology; receptor; response; sound; vibration

Project Summary Cochlear amplification is the process by which our auditory system amplifies and tunes responses to incoming sounds, bestowing us with our excellent sound level sensitivity, large dynamic range, and fine frequency discrimination. Auditory sensory cells have two processes hypothesized to contribute to cochlear amplification: somatic motility that occurs in the cell soma and active hair bundle mechanics that occurs in the apical stereocilia hair bundle. To assay the contribution of active hair bundle mechanics to cochlear amplification requires further understanding of the processes related to it. Hair cell mechanotransduction (MET), the process of converting sound stimuli into electrical signals in the hair bundle, is the driver of active hair bundle mechanics. MET adaptation is one key mechanism that is hypothesized to contribute to active hair bundle mechanics. Previous work in non-mammalian models show that adaptation is separated into fast and slow processes, both of which rely on the influx of calcium to drive the process. Data in the mammalian cochlea indicate that adaptation also consists of fast and slow components, but our work shows that the underlying biology driving the fast and slow processes in the cochlea is fundamentally different from what has been previously reported in non- mammalian hair cells. Thus, new investigations are needed to understand the molecular machinery responsible for both fast and slow adaptation, and their contributions to mammalian auditory processing. From new data about properties of cochlear MET, we hypothesize that tension is essential for adaptation mechanisms. In Aim 1 of this study, we will investigate the contribution of myosin motors to adaptation and hair bundle mechanics. We assay this using new, faster stimulation and high-speed imaging to monitor mechanical changes in the hair bundle coupled with hair cell electrophysiology and pharmacological manipulation. With numerous myosin motors known to be important for auditory function, in Aim 2 we will explore the contributions of specific myosin motors to adaptation and hair bundle mechanics using existing mouse models. For Aim 3, we developed a new mouse model using CRISPR/Cas9 technology to acutely inactivate myosin VIIa motor function, and we will assess the role of myosin VIIa in tension generation. The experiments in this proposal will further our understanding of the molecular mechanisms of mammalian cochlear adaptation and hair bundle mechanics to develop a new model of the mammalian auditory MET process. We are uniquely positioned to accomplish this with the new technologies that we have and continue to develop. Basic mechanistic knowledge of auditory MET will lead to experiments where we can interrogate the system in vivo to determine specific molecular contributions to cochlear amplification. Understanding cochlear amplification can lead to better prevention and/or restoration of hearing.

项目摘要 耳蜗放大是我们的听觉系统放大和调谐对声音的反应的过程。 传入的声音，赋予我们出色的声级灵敏度，大动态范围， 频率鉴别听觉感觉细胞有两个过程假设有助于耳蜗 扩增：发生在细胞索马中的体细胞运动和发生在细胞中的活跃的毛束力学。 顶端静纤毛毛束。分析主动毛束力学对耳蜗放大的贡献 需要进一步了解与之相关的过程。毛细胞机械转导（MET），这一过程 将声音刺激转换为发束中的电信号的过程，是主动发束力学的驱动器。 MET适应是一个关键机制，假设有助于活跃的毛束力学。 以前在非哺乳动物模型中的工作表明，适应分为快速和缓慢的过程， 其中依赖于钙的流入来驱动这一过程。哺乳动物耳蜗的数据表明， 也由快和慢的成分组成，但我们的工作表明，驱动快和慢的基本生物学， 耳蜗中的缓慢过程与以前在非耳蜗中报道的过程根本不同， 哺乳动物的毛细胞因此，需要新的研究来了解负责的分子机制 快速和缓慢的适应，以及它们对哺乳动物听觉处理的贡献。 从关于耳蜗MET特性的新数据中，我们假设张力对于适应是必不可少的 机制等在本研究的目的1中，我们将研究肌球蛋白马达对适应和毛发的贡献。 束力学我们使用新的，更快的刺激和高速成像来监测机械 毛束的变化与毛细胞电生理学和药理学操作相结合。与 已知许多肌球蛋白马达对听觉功能很重要，在目标2中，我们将探讨肌球蛋白马达的作用。 特定的肌球蛋白马达的适应和毛束力学使用现有的小鼠模型。目标3： 使用CRISPR/Cas9技术开发了一种新的小鼠模型，以急性抑制肌球蛋白VIIa运动功能， 我们将评估肌球蛋白VIIa在张力产生中的作用。 本实验将进一步加深我们对哺乳动物细胞凋亡的分子机制的认识 耳蜗适应和毛束力学，以开发哺乳动物听觉MET的新模型 过程我们拥有独特的优势，可以利用我们拥有的新技术实现这一目标，并将继续 开发.听觉MET的基本机械知识将导致实验，我们可以询问 系统在体内，以确定特定的分子贡献耳蜗放大。了解耳蜗 放大可以导致更好的听力预防和/或恢复。