Basic Mechanisms on Hearing Loss of Cochlear Origin

目的：感音神经性听力损失（SNHL）与军事的许多方面密切相关 包括爆炸伤。这项建议的总体目标是改善预防工作， 和退伍军人中SNHL的治疗。 研究设计：我们以前使用体外筛选来鉴定可以保护 毛细胞（HC）的耳毒性损伤。我们在体内测试了它们对噪音引起的听力损失的影响 （NIHL），并发现部分保护。我们还使用了高分辨率蛋白质组学来识别额外的 参与NIHL的过程。总之，我们的研究结果表明，许多细胞过程有助于HC 损害在本申请中，我们提出筛选靶向不同HC的化合物组合 破坏和生存过程，以确定最有效的组合。这将使我们能够 确定进一步开发作为人类药理学干预的最佳策略， 化合物组合和/或多作用化合物。 方法学：将在体外使用氨基糖苷类药物损伤或在体内使用噪声进行研究 对耳蜗的损伤对于体内研究，脑内或鼓室内递送HC保护剂 将在暴露后立即开始。我们将使用一个完善的噪音损伤小鼠模型， 用渗透微型泵将化合物长期递送至耳蜗外淋巴或圆窗， 听性脑干反应（ABR）和畸变产物耳声发射（DPOAE） 听力测定和耳蜗毛细胞和传入神经末梢的形态学评价。 过去供资期间的进展：在过去供资期间，利用哺乳动物 Corti器官是唯一含有损伤敏感的哺乳动物外毛细胞的组织，我们筛选了 几个复合图书馆。我们鉴定了一系列针对不同细胞的化合物， 这些工艺在保护碳氢化合物方面是有效的。然后，我们将选定的化合物转移到一个 噪声性听力损失（NIHL）的体内模型，我们也注意到了保护。我们也 完成了首次NIHL的高分辨率蛋白质组学研究，鉴定了许多蛋白质 以及以前不知道的与噪声损害有关的过程，这些过程是潜在的目标 用于药物治疗我们还进行了第一个高分辨率的蛋白质组研究分离的HC。 此外，我们完成了HC再生相关基因调控的研究，发现 用espin 1的基因治疗显著增强了再生毛细胞上的静纤毛形成。我们 发现了一种由ATP受体介导的新的保护性HC途径， 更高的刺激水平，保护他们免受噪音的伤害。我们的研究导致了18个同行评审 出版至今。 临床关系：SNHL的预防和治疗对退伍军人非常重要 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 在VA中占比任何其他疾病的残疾赔偿金和康复费用 很高。拟议的研究旨在开发新的和改进的治疗方法， 预防和治疗这一严重的健康问题。

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.