Preventing hair cell loss by regulating prestin's function

通过调节 prestin 的功能来防止毛细胞损失

• 批准号: 7933797
• 负责人: Jing Zheng
• 金额: $ 49.08万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-17 至 2012-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7933797
• 关键词: Affect; Amplifiers; Antioxidants; Biochemical; Biological; Carrier Proteins; Cell Death; Cell Survival; Cell physiology; Cells; Data; Development; Ear; Electron Transport; Enzymes; Frequencies; Future; Generations; Goals; Hair Cells; Hearing; Human; In Vitro; Knowledge; Laboratories; Labyrinth; Lead; Libraries; Link; Maintenance; Mammals; Mechanics; Mediating; Membrane; Metabolic; Methods; Molecular; Monitor; Motor; Natural regeneration; Organ of Corti; Outer Hair Cells; Oxidants; Oxidation-Reduction; Oxidative Stress; Physiology; Point Mutation; Prevention; Process; Production; Property; Proteins; Reactive Oxygen Species; Reagent; Reporting; Research; Role; Screening procedure; Sensorineural Hearing Loss; Signal Transduction; Source; Stem cells; System; Testing; Transgenic Mice; Translational Research; Work; base; cell injury; cell motility; design; enzyme activity; gene therapy; hair cell regeneration; hearing impairment; indexing; innovation; mouse model; mutant; novel; prevent; public health relevance; rat Pres protein; response; small molecule; yeast two hybrid system

DESCRIPTION (provided by applicant): Mammals including humans need amplification by outer hair cells (OHCs) for their high sensitivity and sharp frequency selectivity. OHCs are also the most vulnerable cells in the inner ear and are involved in a majority of sensorineural hearing loss. Although OHC regeneration through either stem cell replacement or gene therapy provides an exciting option in the future, preventing hair cell loss is still the most direct and realistic approach to deal with hair cell loss, and including regenerated ones. Therefore, our proposal will focus on the maintenance of hair cells, particularly outer hair cells. OHC death is strongly connected with the generation of reactive oxygen species (ROS) that are known to destroy cells. Why OHCs, as compared to other cells in the organ of Corti, are more vulnerable to ROS is not fully understood. The main function of OHCs is to amplify mechanical signals through their somatic electromotility. This exclusive property is executed by a unique motor protein called prestin, which is expressed only in OHCs. In the past, studying OHC amplification mechanisms and preventing OHC loss were considered as two separate research fields. Unexpectedly, we discovered that non-functional point mutations in prestin (499-prestin mutant) leads to OHC death. In addition, prestin is not only associated with proteins involved in ROS generation, but prestin itself may have redox enzymatic activity, which could be a part of the OHC defense system to minimize ROS. These data indicate a close connection between prestin's function and the vulnerability of OHCs. The goal of this proposal is to understand this link, and subsequently to search for better strategies to prevent OHCs loss. Aim I of this proposal is designed to systematically characterize prestin's redox enzymatic activity in an in vitro system in order to reveal why the OHCs are the most vulnerable cells in the organ of Corti. This knowledge will allow us to develop a better strategy to prevent OHC loss. In Aim II, we will compare cell properties between wt-prestin and mutant 499-prestin expressing cells. Subsequent development of a system and method(s) to monitor the connection between prestin's function and cell vulnerability will then be used to test the effects of different anti-OHC loss reagents on prestin's functions. The information obtained from AIM II will help us to understand the relationship between prestin's function and cell death at the cellular level and provide guidance for selecting better approaches to protect OHCs. Aim III will focus on a search for new compounds through small molecule compound library screening procedures. Our purpose is to find novel compounds that may have specific and potent effects on prestin's redox enzymatic capacity, and are therefore usable for preventing OHC loss. Various cellular, biochemical and molecular biological methods will be used. Our strategies to prevent hair cell loss are based on knowledge derived from understanding prestin's function, which is unique to OHCs. This innovative approach will not only provide crucial information about basic mechanisms of cochlear amplification but it will also lead to a deeper understanding of processes associated with OHC death. The latter may lead to direct treatments or prevention of OHC damage. The proposed work is a first-step in translational research, which bridges basic mechanisms of cochlear physiology and treatments for hearing impairment. PUBLIC HEALTH RELEVANCE: Outer hair cells constitute the cochlear amplifier, essential for providing high sensitivity and frequency selectivity of hearing. They are also the most vulnerable cells in the inner ear and are involved in a majority of sensorineural hearing loss that affects the hearing of millions of people. Prestin, the motor protein of outer hair cells, is required for cochlear amplification. The goal of this proposal is to investigate prestin's protection role against oxidative stress in the ear. Data collected from these studies will not only expand knowledge of prestin as the OHC-based cochlear amplifier at the molecular level, but also produce a deeper understanding of mechanisms associated with outer hair cells loss, and may offer new methods for the prevention of OHC damage.

描述（由申请人提供）：包括人类在内的哺乳动物需要外毛细胞（ohc）扩增，因为它们具有高灵敏度和高频率选择性。OHCs也是内耳中最脆弱的细胞，与大多数感音神经性听力损失有关。虽然通过干细胞替代或基因治疗的OHC再生在未来提供了一个令人兴奋的选择，但防止毛细胞损失仍然是处理毛细胞损失的最直接和最现实的方法，包括再生的毛细胞。因此，我们的建议将重点放在毛细胞的维护，特别是外毛细胞。OHC死亡与活性氧（ROS）的产生密切相关，活性氧可以破坏细胞。为什么OHCs与Corti器官中的其他细胞相比，更容易受到ROS的伤害，目前还不完全清楚。OHCs的主要功能是通过其体电运动性放大机械信号。这种排他性是由一种称为prestin的独特马达蛋白执行的，该蛋白仅在ohc中表达。过去，研究热含量放大机制和防止热含量损失被视为两个独立的研究领域。出乎意料的是，我们发现prestin的无功能点突变（499-prestin突变）导致OHC死亡。此外，prestin不仅与参与ROS生成的蛋白质相关，而且prestin本身可能具有氧化还原酶活性，这可能是OHC防御系统的一部分，以减少ROS。这些数据表明，prestin的功能与OHCs的脆弱性密切相关。本建议的目标是了解这种联系，并随后寻求更好的战略来防止OHCs的损失。本提案的目的1旨在系统地表征prestin在体外系统中的氧化还原酶活性，以揭示为什么OHCs是Corti器官中最脆弱的细胞。这一知识将使我们能够制定更好的战略来防止热盐流失。在Aim II中，我们将比较wt-prestin和突变型499-prestin表达细胞之间的细胞特性。随后开发的系统和方法来监测prestin的功能和细胞脆弱性之间的联系，然后将用于测试不同的抗ohc损失试剂对prestin功能的影响。AIM II获得的信息将有助于我们在细胞水平上理解prestin的功能与细胞死亡之间的关系，并为选择更好的OHCs保护方法提供指导。Aim III将专注于通过小分子化合物库筛选程序寻找新化合物。我们的目的是寻找可能对prestin的氧化还原酶能力具有特异性和强效作用的新化合物，因此可用于防止OHC损失。将使用各种细胞、生化和分子生物学方法。我们预防毛细胞损失的策略是基于对前列腺素功能的理解，这是OHCs所独有的。这种创新的方法不仅将提供有关耳蜗放大基本机制的重要信息，而且还将导致对OHC死亡相关过程的更深入理解。后者可能导致直接治疗或预防OHC损伤。这项工作是翻译研究的第一步，它将耳蜗生理学的基本机制与听力障碍的治疗联系起来。