Molecular mechanisms of cochlear hair bundle mechanics

耳蜗毛束力学的分子机制

• 批准号: 9920119
• 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 2023-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9920119
• 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; 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/antagonist; 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音的过程 传入的声音，以我们出色的声音敏感性，较大的动态范围和良好的声音赋予我们 频率歧视。听觉感觉细胞有两个过程，假设有助于人工耳蜗 放大：在细胞体内发生的体细胞运动和发生在活跃的头发束机制中 顶端立体胶质束。分析主动发束力学对人工耳蜗扩增的贡献 需要进一步了解与之相关的过程。毛细胞机械转导（MET），该过程 主动束机械师的驱动力是将声音刺激转换为发束的电信号。 MET适应性是一种关键机制，该机制是一种有助于主动束机械师的关键机制。 非哺乳动物模型中的先前工作表明，适应被分为快速和缓慢的过程 其中依靠钙的涌入来推动过程。哺乳动物耳蜗中的数据表明适应 还包括快速和缓慢的组成部分，但我们的工作表明，潜在的生物学驱动了快速和 耳蜗中的缓慢过程与以前在非 - 哺乳动物毛细胞。因此，需要进行新的研究以了解负责的分子机械 对于快速和缓慢的适应，及其对哺乳动物听觉处理的贡献。 从有关人工耳蜗属性的新数据中，我们假设张力对于适应至关重要 机制。在本研究的目标1中，我们将研究肌球蛋白电机对适应和头发的贡献 捆绑机制。我们使用新的，更快的刺激和高速成像来监测机械，对此进行测定 头发束的变化以及毛细胞电生理学和药理操作的变化。和 许多已知对听觉功能很重要的肌球蛋白电动机，在AIM 2中，我们将探索贡献 使用现有鼠标模型的特定肌球蛋白电动机来适应和发束力学。对于目标3，我们 使用CRISPR/CAS9技术开发了一种新的鼠标模型，以急性灭活肌球蛋白VIIA运动功能， 我们将评估肌球蛋白VIIA在张力产生中的作用。 该提案中的实验将进一步了解我们对哺乳动物分子机制的理解 人工耳蜗适应和发束机制以开发哺乳动物听觉的新模型 过程。我们拥有独特的位置，可以用我们拥有并继续的新技术来实现这一目标 发展。听觉的基本机械知识将导致实验，我们可以在其中询问 体内系统，以确定对耳蜗扩增的特定分子贡献。了解人工耳蜗 扩增会导致更好的预防和/或恢复听力。