Calcium Regulation of Mechanotransduction

机械传导的钙调节

• 批准号: 7850399
• 负责人: Anthony J Ricci
• 金额: $ 35.21万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-17 至 2011-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7850399
• 关键词: Accounting; Address; Affect; Age; Anatomy; Arts; Auditory system; Calcium; Cells; Cochlea; Coupled; Coupling; Cytoskeleton; Dependence; Development; Dose; Electron Microscopy; Environment; Event; Frequencies; Guidelines; Hair; Hair Cells; Image; Individual; Injection of therapeutic agent; Inner Hair Cells; Kinetics; Knowledge; Laser Scanning Confocal Microscopy; Link; Lipids; Measurement; Measures; Mechanical Stimulation; Mechanics; Membrane; Molecular; Movement; Myosin ATPase; Noise; Optics; Pathway interactions; Preventive Intervention; Process; Property; Rattus; Regulation; Relative (related person); Replacement Therapy; Research Personnel; Role; Sensory Hair; Side; Signal Transduction; Site; Stereocilium; Stretching; System; Techniques; Testing; Time; Tinnitus; Turtles; Variant; deafness; hair cell regeneration; hearing impairment; insight; mathematical model; prevent; research study; response; sound; tissue culture; tool; two-photon; vibration; voltage

DESCRIPTION (provided by applicant): Deflection of the sensory hair cell's hair bundle (mechanotransduction) results in an electrical response from the hair cell that is the primary signal for audition. Disruption of this pathway by noise, ototoxic agents or aging leads to maladies such as threshold shifts (both temporary and permanent), hearing loss, deafness at an extreme and may even underlie some forms of Tinnitus. Understanding the mechanisms involved in the mechanotransduction process should help identify sites for intervention and prevention of hearing loss and may also provide guidelines for development of replacement therapies such as hair cell regeneration. Although a great deal of knowledge regarding mechanotransduction has accrued over the past 25 years, many fundamental questions regarding mechanisms and functions remain to be elucidated. Experiments herein will use state of the art optical and electrical techniques coupled with tissue culture and pharmacological tools to probe several basic questions regarding hair cell mechanotransduction. Specific Aim (SA) 1 will determine whether the functional mechano electric transduction (MET) channels are located at the tops or along the sides of the stereocilia by taking advantage of the morphological arrangement of inner hair cell bundles. It will determine the number of channels per stereocilia by coupling calcium imaging of individual stereocilia with measurements of MET current. Finally, it will determine the role of membrane tension on channel gating which should give insight into whether the MET channel is directly tethered to the tip-link or cytoskeleton or whether it is activated via membrane stretch. SA2 will investigate the Ca2+ dependence of adaptation and activation by coupling Ca2+ imaging, Ca2+ uncaging and electrophysiological measurements of MET currents. These experiments will attempt to separate calcium-dependent responses from mechanical stimulation and should yield important new kinetic information regarding the calcium regulation of transduction and adaptation. Experiments will also explore the Ca2+ dependence of hair bundle mechanics. SA3 will investigate single channel MET properties to determine the mechanism by which Ca2+ regulates channel conductance and open time. SA4 will test the hypothesis that MET provides mechanical tuning to the hair cell.

描述（由申请人提供）：感觉毛细胞毛束的偏转（机械转导）导致毛细胞产生电响应，这是听觉的主要信号。噪音、耳毒性物质或衰老对这条通路的破坏会导致疾病，例如阈值变化（暂时的和永久性的）、听力损失、极度耳聋，甚至可能导致某些形式的耳鸣。了解机械转导过程中涉及的机制应有助于确定干预和预防听力损失的部位，还可以为开发毛细胞再生等替代疗法提供指导。尽管在过去 25 年里人们积累了大量有关机械转导的知识，但有关机制和功能的许多基本问题仍有待阐明。本文的实验将使用最先进的光学和电学技术以及组织培养和药理学工具来探讨有关毛细胞机械转导的几个基本问​​题。具体目标 (SA) 1 将利用内毛细胞束的形态排列来确定功能性机械电转导 (MET) 通道是位于静纤毛的顶部还是沿着其侧面。它将通过将单个静纤毛的钙成像与 MET 电流测量相结合来确定每个静纤毛的通道数量。最后，它将确定膜张力对通道门控的作用，从而深入了解 MET 通道是否直接连接到尖端连接或细胞骨架，或者是否通过膜拉伸激活。 SA2 将通过耦合 Ca2+ 成像、Ca2+ 解笼锁和 MET 电流的电生理测量来研究适应和激活的 Ca2+ 依赖性。这些实验将尝试将钙依赖性反应与机械刺激分开，并应产生关于转导和适应的钙调节的重要的新动力学信息。实验还将探索发束力学对 Ca2+ 的依赖性。 SA3 将研究单通道 MET 特性，以确定 Ca2+ 调节通道电导和开放时间的机制。 SA4 将测试 MET 为毛细胞提供机械调节的假设。