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）：感觉毛细胞的头发束的挠度（机械转移）导致毛细单元的电响应，这是试镜的主要信号。通过噪声，耳毒剂或衰老来破坏这一途径，导致疾病，例如阈值移位（临时和永久性），听力损失，极端的耳聋，甚至可能是某些形式的耳鸣。了解机械转移过程中涉及的机制应有助于确定干预和预防听力损失的地点，并可能为开发替代疗法（例如毛细胞再生）提供指南。尽管在过去25年中，关于机械转移的大量知识已有很多，但有关机制和功能的许多基本问题仍有待阐明。这里的实验将使用最先进的光学和电气技术，再加上组织培养和药理学工具，以探测有关毛细胞机械转移的几个基本问​​题。特定的目标（SA）1将通过利用内毛细胞束的形态排列来确定功能机械电气转导（MET）通道是否位于立体胶质的顶部或沿立体胶质的侧面。它将通过将单个立体胶质的钙成像与MET电流的测量结合钙成像来确定每个立体胶质的通道数。最后，它将确定膜张力在通道门控的作用，该膜张力应深入了解MET通道是否直接束缚在尖端连接或细胞骨架上，或者是否通过膜拉伸激活。 SA2将通过耦合Ca2+成像，Ca2+分离和电生理测量值来研究适应和激活的Ca2+依赖性。这些实验将尝试将依赖钙的反应与机械刺激分开，并应产生有关转导和适应的钙调节的重要新动力学信息。实验还将探索发束力学的Ca2+依赖性。 SA3将研究单个通道符合特性，以确定CA2+调节通道电导和开放时间的机制。 SA4将测试MET的假设，即MET为毛细单元提供机械调整。