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.

翻译后摘要：听觉和前庭感觉细胞使用的毛束，一个阶梯状阵列的肌动蛋白填充 静纤毛，将机械运动转化为电信号。机械门控（MET）离子通道 位于较短的静纤毛的顶端的“第一”和“第二”被通过拉动顶端链接而产生的力激活， 在静纤毛之间由于感觉毛束是遗传性疾病如Ushers综合征的主要部位， 而且也容易受到噪音和老化的影响，因此了解这些线束的工作方式至关重要 设计预防和恢复功能的治疗方法。哺乳动物耳蜗毛束有着不寻常的 形态和静纤毛间连接性不像其他内耳末端器官那样紧密。有 关于影响MET电流和毛束的潜在过程的机制存在相当大的争论 机制，如快速和缓慢的适应，门控顺应性和电压驱动的响应。有进一步 关于我们是否真的有MET电流反应和机械，分子 机制等在能够使用新发现的MET分子的遗传操作的力量之前，我们 需要清楚地了解毛束的生物物理特性以及它们如何影响MET受体电流。 我们假设在发束运动中缺乏连通性是为了优化发束对自然光的响应。 静纤毛刺激和同步化来自于顶盖膜（OHCs）或液体 刺激（IHC）。我们进一步假设，我们将确定机械相关的快速和缓慢的适应 以及门控依从性;然而，我们确实希望与其他毛发相比， 细胞类型，而且缓慢适应的机制将不符合经典理论。最后我们 假设MET通道特性与毛束力学一起工作以产生受体调谐 电流我们将在以下具体目标中研究这些假设中的每一个。SA 1将生成一个 大鼠MET通道和毛束在多个频率位置的特性的综合数据集， 小鼠P10-12龄。利用宽探头、流体射流和新的 开发的窄探针，我们可以分开MET通道和毛束属性。SA 2将直接 使用新开发的高速成像解决发束力学和已知发束特性 使用窄探头或流体喷射技术。实验将针对MET通道门控合规性、快速和 缓慢适应和电压依赖性机械毛束反应。SA 3将生成频率 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 通道和发束之间的距离这些目标的完成将提供前所未有的数量水平， 关于发束如何移动以及这种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。