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）的高灵敏度和急剧的频率选择性。 OHC也是内耳中最脆弱的细胞，并且参与了大多数感觉性听力损失。尽管通过干细胞置换或基因疗法的OHC再生在将来提供了令人兴奋的选择，但防止毛细胞损失仍然是处理毛细胞损失以及包括再生的最直接和现实的方法。因此，我们的建议将集中于维持毛细胞，尤其是外毛细胞。 OHC死亡与已知会破坏细胞的活性氧（ROS）的产生密切相关。为什么与Corti器官中其他细胞相比，OHC更容易受到ROS的影响。 OHC的主要功能是通过其体细胞电动性扩增机械信号。该独家属性由一种名为Prestin的独特运动蛋白执行，该蛋白仅在OHC中表达。过去，研究OHC扩增机制和防止OHC丢失被认为是两个独立的研究领域。出乎意料的是，我们发现Prestin（499-Prestin突变体）中的非功能点突变导致OHC死亡。此外，普雷斯汀不仅与参​​与ROS产生的蛋白质有关，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，以最大程度地减少ROS。这些数据表明Prestin的功能与OHC的脆弱性之间有密切的联系。该提案的目的是了解此链接，然后寻找更好的策略来预防OHCS损失。该建议的目的I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OHC是Corti器官中最脆弱的细胞。这些知识将使我们能够制定更好的策略来防止OHC损失。在AIM II中，我们将比较wt-prestin和突变体499-prestin表达细胞之间的细胞特性。然后，随后开发系统和方法来监视Prestin功能与细胞脆弱性之间的连接，然后将用于测试不同抗OHC损耗试剂对Prestin功能的影响。从AIM II获得的信息将有助于我们了解Prestin功能与细胞水平上的细胞死亡之间的关系，并为选择更好的OHC方法提供指导。 AIM III将通过小分子化合物库筛选程序专注于搜索新化合物。我们的目的是找到可能对普雷斯汀的氧化还原酶能力具有特定且有效影响的新型化合物，因此可用于预防OHC损失。将使用各种细胞，生化和分子生物学方法。我们防止毛细胞损失的策略是基于了解Prestin功能的知识，而Prestin的功能是OHC的独特之处。这种创新的方法不仅将提供有关人工耳蜗放大基本机制的关键信息，而且还将导致对与OHC死亡相关的过程的更深入了解。后者可能导致直接治疗或预防OHC损害。拟议的工作是翻译研究的第一步，它桥接了人工耳蜗生理和听力障碍的治疗方法的基本机制。 公共卫生相关性：外毛细胞构成人工耳蜗放大器，对于提供高灵敏度和听力的频率选择性至关重要。它们也是内耳中最脆弱的细胞，并且参与了影响数百万人听力的大多数感觉性听力损失。 Prestin是外毛细胞的运动蛋白，是人工耳蜗扩增所必需的。该提案的目的是调查Prestin对耳朵中氧化应激的保护作用。从这些研究中收集的数据不仅会扩大对分子水平上基于OHC的人工耳蜗的知识，而且还会对与外毛细胞损失相关的机制产生更深入的了解，并可能为预防OHC损害提供新的方法。