Basic Mechanisms on Hearing Loss of Cochlear Origin

目的：感音神经性耳聋(SNHL)与军事上的许多方面密切相关 包括爆炸伤在内的服务。这项建议的总体目标是改善预防 以及退伍军人SNHL的治疗。 研究设计：我们先前使用体外筛选的方法来确定能够保护 毛细胞(HCS)免受耳毒性损伤。我们在体内测试了它们对抗噪音引起的听力损失。 (NIHL)，并发现了部分保护。我们还使用了高分辨率蛋白质组学来识别其他 NIHL涉及的流程。总体而言，我们的结果表明，许多细胞过程对HC有贡献 损坏。在本应用中，我们建议筛选针对不同HC的化合物组合 损害和生存过程，以确定最有效的组合。这将使我们能够 确定进一步发展的最佳策略，作为对人类的药物干预，使用 化合物组合和/或多作用化合物。 方法：使用氨基糖苷损伤进行体外研究，或使用噪声进行体内研究 对耳蜗骨造成损伤。对于活体研究，HC保护剂的卵泡内或鼓室内给药 将在暴露后立即开始。我们将使用一个成熟的噪声损伤小鼠模型， 将化合物慢性输送到耳蜗外淋巴或带有渗透性小泵的圆形窗口， 系列听性脑干反应和失真产物耳声发射 测听，并对耳蜗轴突和传入神经末梢进行形态评价。 过去筹资期间的进展：在过去筹资期间，使用哺乳动物 Corti器官，唯一包含损伤敏感的哺乳动物外层HCS的组织，我们筛选出 几个复合库。我们确定了一系列针对不同细胞的化合物 进程，这些进程有效地保护了HC。然后我们将选定的化合物转移到In 噪声性听力损失(NIHL)的活体模型，我们还注意到了保护作用。我们也 完成了有史以来第一次NIHL的高分辨率蛋白质组学研究，鉴定了许多蛋白质 以及以前未知的涉及噪声损害的进程，这些进程是潜在的目标 接受药物治疗。我们还对分离的HCS进行了第一次高分辨率蛋白质组学研究。 此外，我们完成了与HC再生相关的基因调控研究，发现 使用espin1的基因治疗显著促进再生的hcs上的立体纤毛形成。我们 发现了一种由ATP受体介导的新的保护性HC通路，该通路可降低Hcs的活性 高刺激水平，保护它们免受噪音损害。我们的研究结果是18项同行评议 到目前为止的出版物。 临床关系：预防和治疗SNHL对退伍军人至关重要 和退伍军人事务部。SNHL对退伍军人生活质量的影响是巨大的。SNHL和耳鸣也 退伍军人事务部的残疾补偿比其他任何疾病都要多，康复费用也更高 都很高。这项拟议的研究旨在开发新的和改进的治疗方法 预防和治疗这一重要的健康问题。

Objectives: Sensorineural hearing loss (SNHL) is strongly associated with many aspects of military service including blast injury. The overall objectives of this proposal are to improve the prevention and treatment of SNHL in Veterans. Research Design: We previously used in vitro screening to identify novel compounds that can protect hair cells (HCs) from ototoxic damage. We tested them in vivo against noise-induced hearing loss (NIHL) and found partial protection. We also used high-resolution proteomics to identify additional processes involved in NIHL. Overall, our results suggest that many cellular processes contribute to HC damage. In this application we propose to screen compound combinations targeting diverse HC damage and survival processes, to identify the most effective combinations. This will allow us to identify optimal strategies for further development as pharmacological interventions in humans, using compound combinations and/or multi-acting compounds. Methodology: Studies will be performed in vitro using aminoglycoside damage or in vivo using noise damage to the cochlea. For in vivo studies, intracochlear or intratympanic delivery of HC protectants will begin immediately after exposure. We will use a well-established mouse model of noise damage, chronic delivery of compounds to cochlear perilymph or the round window with osmotic minipumps, serial auditory brainstem response (ABR) and distortion product otoacoustic emission (DPOAE) audiometry, and morphological evaluation of cochlear HCs and afferent nerve endings. Progress over the past period of funding: During the past period of funding, using the mammalian organ of Corti, the only tissue containing the damage-sensitive mammalian outer HCs, we screened several compound libraries. We identified a broad range of compounds targeting different cellular processes, that were effective in protecting HCs. We then transferred selected compounds to an in vivo model of noise-induced hearing loss (NIHL), where we also noted protection. We also completed the first-ever high-resolution proteomics study of NIHL, which identified many proteins and processes not previously known to be involved in noise damage, and which are potential targets for pharmacotherapy. We also performed the first high-resolution proteomic study of isolated HCs. In addition, we completed studies of gene regulation relevant to HC regeneration, and found that gene therapy with espin1 dramatically enhanced stereocilia formation on regenerating HCs. We discovered a novel protective HC pathway mediated by ATP receptors that reduce activity in HCs at high stimulus levels, protecting them from noise damage. Our studies resulted in 18 peer-reviewed publications to date. Clinical Relationship: The prevention and treatment of SNHL is of great importance to Veterans and the VA. The effects of SNHL on Veterans’ quality of life are substantial. SNHL and tinnitus also account for more disability compensation in the VA than any other disorder, and rehabilitation costs are high. The proposed research is targeted at developing new and improved therapies for prevention and treatment of this important health problem.