Probing how hair bundle mechanical properties shape the mechanotransducer receptor current

探讨发束机械特性如何塑造机械传感器受体电流

• 批准号: 10778103
• 负责人: Anthony J Ricci
• 金额: $ 66.42万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-18 至 2028-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10778103
• 关键词: ATP phosphohydrolase; Acoustic Stimulation; Actins; Address; Age; Aging; Animals; Auditory; Biophysics; Brain; Buffers; Calcium; Cells; Characteristics; Cochlea; Coupled; Data; Data Set; Endolymph; Foundations; Frequencies; Generations; Genetic Diseases; Goals; Hair; Hair Cells; Image; Individual; Inner Hair Cells; Intervention; Investigation; Ion Channel Gating; Kinetics; Labyrinth; Link; Liquid substance; Location; Mechanical Stimulation; Mechanics; Modeling; Molecular; Monitor; Morphology; Motion; Motor; Mus; Noise; Organ; Organ Model; Organelles; Outer Hair Cells; Phosphatidylinositol 4,5-Diphosphate; Physiological; Positioning Attribute; Predisposition; Prevention therapy; Process; Property; Protocols documentation; Rana; Rattus; Receptor Cell; Reporting; Role; Rotation; Saccule structure; Sensory; Sensory Hair; Shapes; Signal Pathway; Signal Transduction; Site; Speed; Stereocilium; Stimulus; Technology; Testing; Translating; Turtles; Usher Syndrome; Work; antagonist; biophysical properties; cell type; channel blockers; experimental study; genetic manipulation; insight; mechanical properties; receptor; response; restoration; synergism; tectorial membrane; theories; therapy design; tongue papilla; voltage

Abstract: Auditory and vestibular sensory cells use the hair bundle, a stair-cased array of actin filled stereocilia, to translate mechanical motion into an electrical signal. Mechanically-gated (MET) ion channels located at the tips of shorter stereocilia are activated by force created by the pulling of a tip link that extends between stereocilia. As sensory hair bundles are a major site for both genetic disorders like Ushers syndrome and are also susceptible to damage from noise and aging, understanding how these bundles operate is critical to designing therapies for prevention and restoration of function. Mammalian cochlear hair bundles have unusual morphologies and interstereocilia connectivity that is not as tight as other inner ear end organs. There is considerable debate as to the mechanisms underlying processes impacting MET currents and hair bundle mechanics, like fast and slow adaptation, gating compliance and voltage driven responses. There is further controversy over whether we truly have causal links between MET current responses and mechanical, molecular mechanisms. Before being able to use the power of genetic manipulation of newly identified MET molecules, we need a clear understanding of hair bundle biophysical properties and how they impact MET receptor currents. We hypothesize that the lack of connectivity in bundle motion is to optimize the hair bundle's response to natural stimulation and that synchronization of stereocilia comes from the tectorial membrane (OHCs) or the fluid stimulation (IHCs). We further hypothesize that we will identify mechanical correlates for fast and slow adaptation as well as gating compliance; however, we do expect there to be less slow adaptation as compared to other hair cell types but also that the mechanism of slow adaptation will not align with classical theories. And finally. we hypothesize that MET channel properties work with hair bundle mechanics to create tuning of the receptor current. We will investigate each of these hypotheses in the following specific aims. SA1 will generate a comprehensive data set of MET channel and hair bundle properties at multiple frequency positions from rats and mice P10-12 of age. By taking advantage of three modes of stimulations, wide probe, fluid jet and the newly developed narrow probe, we can separate between MET channel and hair bundle properties. SA2 will directly address hair bundle mechanics and known hair bundle properties using the newly developed high-speed imaging with either narrow probe or fluid jet technology. Experiments will target MET channel gating compliance, fast and slow adaptation and voltage dependent mechanical hair bundle responses. SA3 will generate frequency response curves under physiological conditions using the wide probe and fluid jet to define the filtering properties of the channel and the hair bundle. Completion of these aims will provide an unprecedented level of quantitative information as to how the hair bundle moves and how this motion shapes the MET receptor current generated. They will be the standard by which molecular manipulations can be assessed.

摘要：听觉和前庭感觉细胞使用发束，这是一个充满肌动蛋白的阶梯阵列。 静纤毛，将机械运动转化为电信号。机械门控 (MET) 离子通道 位于较短静纤毛的尖端，通过拉动延伸的尖端连杆产生的力来激活 静纤毛之间。由于感觉毛束是亚瑟综合症等遗传性疾病的主要部位 并且还容易受到噪音和老化的损坏，了解这些束的工作原理至关重要 设计预防和恢复功能的疗法。哺乳动物的耳蜗毛束具有不寻常的特征 形态和立体纤毛间的连接不像其他内耳末端器官那么紧密。有 关于影响 MET 电流和发束的潜在过程的机制存在相当多的争论 机制，例如快速和慢速适应、门控顺应性和电压驱动响应。还有进一步 关于 MET 当前反应与机械、分子之间是否确实存在因果关系的争议 机制。在能够利用新鉴定的 MET 分子的基因操纵能力之前，我们 需要清楚地了解发束的生物物理特性以及它们如何影响 MET 受体电流。 我们假设发束运动中缺乏连通性是为了优化发束对自然的响应 刺激和静纤毛的同步来自盖膜 (OHC) 或液体 刺激（IHC）。我们进一步假设我们将识别快速和慢速适应的机械相关性 以及控制合规性；然而，我们确实预计与其他毛发相比，适应速度不会那么慢 细胞类型，而且缓慢适应的机制与经典理论不一致。最后。我们 假设 MET 通道特性与发束力学一起作用以调节受体 当前的。我们将在以下具体目标中研究每个假设。 SA1将生成一个 大鼠和小鼠在多个频率位置的 MET 通道和发束特性的综合数据集 P10-12 龄小鼠。通过利用三种刺激模式：宽探头、流体喷射和最新的 开发了窄探头，我们可以区分 MET 通道和发束特性。 SA2将直接 使用新开发的高速成像技术解决发束力学和已知的发束特性 采用窄探头或流体喷射技术。实验将针对 MET 通道门控合规性、快速且 缓慢的适应和电压依赖的机械发束响应。 SA3将产生频率 生理条件下的响应曲线，使用宽探头和流体射流来定义过滤特性 通道和发束。这些目标的完成将提供前所未有的定量水平 有关发束如何移动以及该运动如何塑造所产生的 MET 受体电流的信息。 它们将成为评估分子操作的标准。