Cytoskeletal Regulation of Outer Hair Cell Motility

我们研究的长期目标是了解参与的分子机制， 外毛细胞（OHC）运动和耳蜗放大的调节，这是发展耳蜗的关键知识。 旨在预防耳蜗损伤和感音神经性听力损失的战略。我们已经确认了罗 GTP酶（RhoA、Rac和Cdc 42）作为体内稳态调节的关键信号分子 和不依赖于Prestin的OHC运动。稳态控制最终将通过 Rho介导的肌动蛋白丝动力学、肌动蛋白-血影蛋白网络的完整性、肌动蛋白-肌动蛋白-血影蛋白-肌动蛋白 质膜-细胞骨架连接，或在所有上述复杂的分子网络 细胞皮层不同层次的反应。我们以前的研究赋予了一个重要的作用， RhoA/ROCK/LIMK 2/cofilin和RhoA/ROCK/内收蛋白信号级联调节OHC运动， 并提出Rac 1/Cdc 42介导的信号也可能是这一过程的关键。这些结果 使我们充分研究了细胞因子介导的调节的分子信号通路， OHC运动性，以理解OHC机械稳态的分子基础。作为 短期目标，我们建议使用电生理学，药理学，显微镜和分子 生物技术以及一种新的方法和创新的图像分析系统 基于超高速摄像机的记录来阐明的调节途径 prestin依赖性和prestin非依赖性OHC运动在低和听觉频率，通过解决 1.确定Rac 1-Cdc 42/PAK 1/LIMK 1/cofilin信号通路在 OHC运动的调节，及其与RhoA/ROCK/LIMK 2/cofilin途径的相互作用。二- 确定RhoA/mDia 1/profilin信号通路在OHC运动调节中的作用;以及3 - 确定RhoA/ROCK-PKC/内收蛋白信号通路在OHC运动调节中的作用。我们 我们相信，实现这些目标将提供有关的作用， 细胞骨架在OHC运动调节中的作用。 OHC的损伤和耳蜗放大机制是感觉神经性聋最常见的原因， 听力损失，这是一种困扰世界各地数百万人的疾病。了解细胞和分子 OHC运动和耳蜗放大的基础将提供关键的见解， 正常人听力和耳聋，这是制定临床策略的关键一步， 预防或改善感音神经性听力损失。

The long-term objective of our research is to understand the molecular mechanisms involved in the regulation of outer hair cell (OHC) motility and cochlear amplification, a critical knowledge for developing strategies aimed at preventing cochlear damage and sensorineural hearing loss. We have identified Rho GTPases (RhoA, Rac and Cdc42) as key signaling molecules in the homeostatic regulation of prestindependent and prestin-independent OHC motility. Homeostatic control would be ultimately achieved through Rho-mediated changes in actin-filament dynamics, in the integrity of the actin-spectrin network, in the plasma membrane-cytoskeleton connection, or in all of the above in a complex network of molecular reactions at different levels of the cell cortex. Our previous studies assigned an important role to the RhoA/ROCK/LIMK2/cofilin and RhoA/ROCK/adducin signaling cascades in the regulation of OHC motility, and suggested that Rac1/Cdc42-mediated signals could also be crucial for this process. These results have led us to fully investigate the molecular signaling pathways underlying cytoskeleton-mediated regulation of OHC motility towards an understanding of the molecular basis of OHCs' mechanical homeostasis. As a short-term objective, we propose to use electrophysiological, pharmacological, microscopy and molecular biology techniques ¿as well as a novel methodological approach and an innovative image analysis system based on recordings with an ultra high-speed video camera¿ to elucidate the regulatory pathways of prestin-dependent and prestin-independent OHC motility at low and auditory frequencies, by addressing the following Specific Aims: 1 - Determine the role of the Rac1-Cdc42/PAK1/LIMK1/cofilin signaling pathway in the regulation of OHC motility, and its interaction with the RhoA/ROCK/LIMK2/cofilin pathway. 2 - Determine the role of the RhoA/mDia1/profilin signaling pathway in the regulation of OHC motility; and 3 - Determine the role of the RhoA/ROCK-PKC/adducin signaling pathway in the regulation of OHC motility. We are confident that accomplishing these aims will provide essential information about the role of the cytoskeleton in the regulation of OHC motility. Damage of OHCs and the mechanism of cochlear amplification is the most common cause of sensorineural hearing loss, a condition afflicting millions of people around the world. Understanding the cell and molecular basis of OHC motility and cochlear amplification will provide critical insights into the basic mechanisms of both normal human hearing and deafness, a critical step for developing clinical strategies aimed at preventing or ameliorating sensorineural hearing loss.