Cytoskeletal Regulation of Outer Hair Cell Motility

外毛细胞运动的细胞骨架调节

基本信息

批准号：
6758563
负责人：
FEDERICO KALINEC
金额：
$ 36.45万
依托单位：
HOUSE RESEARCH INSTITUTE
依托单位国家：
美国
项目类别：
财政年份：
2002
资助国家：
美国
起止时间：
2002-07-01 至 2007-06-30
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): Cochlear outer hair cells (OHCs) are unique sensory-motor cells responsible for signal amplification and frequency discrimination in the mammalian inner ear. Strong evidence suggests that the motile response of OHCs to chemical or electrical stimulation provides the mechanical effectors to the "cochlear amplifier," the active mechanism that enhances approximately 100-fold the peak of the sound-induced basilar membrane motion. Our long-term goal is to understand the molecular mechanisms involved in the regulation of OHC motility. Based on previous studies in non-auditory cell populations, we hypothesize that OHC motility is regulated by structural and functional changes in the cytoskeleton. The recent identification of the small Rho GTPases RhoA, Rac 1 and Cdc42 as mediators in an acetyicholine (ACh)-activated signaling pathway that modulates OHC motility, offers now the opportunity to address this hypothesis at molecular and cellular levels. Moreover, our preliminary results indicate that some downstream effectors of Rho GTPases -belonging to the ACh-activated signaling pathway- are important for OHCs' mechanical homeostasis. Since these downstream effectors mediate Rho-promoted processes such as actin-spectrin association and plasma membrane-cytoskeleton interaction, these results provide a solid foundation for further investigation of the role of the cytoskeleton in the regulation of OHC motility. In this proposal, we will use a combination of electrophysiological, molecular biology, microscopical and image analysis techniques in order to: 1. Identify downstream effectors of Rho GTPases involved in the regulation of OHC motility, 2. Determine the connection pattern between Rho GTPases and their downstream effectors, and 3. Establish the structural changes induced by ACh on the OHC cytoskeleton. We are confident that accomplishing these aims will provide essential information about the role of the cytoskeleton in the regulation of OHC motility as well as critical insights into the basic mechanisms of both normal human hearing and deafness.

描述（由申请人提供）：耳蜗外毛细胞（OHC）是独特的感觉运动细胞，负责哺乳动物内耳中的信号放大和频率辨别。强有力的证据表明，OHC 对化学或电刺激的运动反应为“耳蜗放大器”提供了机械效应器，这种主动机制可将声音引起的基底膜运动峰值增强约 100 倍。我们的长期目标是了解 OHC 运动调节所涉及的分子机制。根据之前对非听觉细胞群的研究，我们假设 OHC 运动受到细胞骨架结构和功能变化的调节。最近鉴定出小 Rho GTP 酶 RhoA、Rac 1 和 Cdc42 作为乙酰胆碱 (ACh) 激活的信号通路中调节 OHC 运动的介质，这为在分子和细胞水平上解决这一假设提供了机会。此外，我们的初步结果表明，Rho GTPases 的一些下游效应器（属于 ACh 激活信号通路）对于 OHC 的机械稳态很重要。由于这些下游效应器介导 Rho 促进的过程，如肌动蛋白-血影蛋白关联和质膜-细胞骨架相互作用，这些结果为进一步研究细胞骨架在 OHC 运动调节中的作用奠定了坚实的基础。在本提案中，我们将结合使用电生理学、分子生物学、显微镜和图像分析技术，以便： 1. 识别参与 OHC 运动调节的 Rho GTPases 下游效应器， 2. 确定 Rho GTPase 和 OHC 运动之间的连接模式其下游效应子，以及 3. 确定 ACh 在 OHC 细胞骨架上诱导的结构变化。我们相信，实现这些目标将提供有关细胞骨架在 OHC 运动调节中的作用的重要信息，以及对正常人类听力和耳聋的基本机制的重要见解。