Elucidation of Under-Investigated Biological Mechanisms of Age-Related Hearing Loss

摘要 该提案将建立一个关于自噬和年龄相关性听力损失（ARHL）的概念验证; 是我们不断扩大的老龄化人口中一种高度流行的沟通和神经感觉障碍， 全世界数以亿计，每年花费数十亿美元用于管理和干预。 临床干预在许多方面特别具有挑战性，因为ARHL的机制并不复杂。 清楚该提案具有高度创新性，因为它旨在为新的生物技术进行转化研究。 突破性的策略，基于听觉系统中与年龄相关的自噬变化与 ARHL的进展。在正在进行的实验中，我们发现了与年龄相关的自噬积累， 哺乳动物耳蜗中的LC 3和p62等标志物。我们的体内周转实验表明， 自噬流应激可能存在于自溶酶体形成步骤中。我们还发现抑制自噬 膜Na，K-ATPase（NKA）和Na ~+-氯化钾（KCl）的表达均降低 在SV-细胞系（SV-K1）中的协同转运蛋白（NKCC 1）。这是两个关键的离子通道， 耳蜗内电位（EP）正常听力。根据我们的新发现，我们假设衰老可能会影响 耳蜗的感觉、神经和代谢方面通过与年龄相关的自噬应激。所以我们 建议进行逐步的细胞机制研究，以全面了解 老年耳蜗的自噬现象本提案的目的有三：首先，我们将确定 自噬应激是否是听力损失的普遍特征。几种自噬抑制剂将用于 处理年轻的成年CBA/CaJ小鼠，并测量它们的听力和生物标志物的变化。第二、 自噬通量应激在耳蜗中的功能作用，包括年龄相关的凋亡和SV相关的离子 将调查信道活动。第三，我们将确定自噬通量中的目标步骤， 在耳蜗中施加影响，并为ARHL的未来干预探索原始可行的方法。这 该项目有望为ARHL生物学机制的未知领域提供新的见解， 解决了许多谜团，这不仅将促进对耳蜗老化过程的更好理解， 促进制定更复杂和有效的ARHL预防和治疗方案。

ABSTRACT This proposal will establish a proof-of-concept relating autophagy and age-related hearing loss (ARHL); which is a highly-prevalent communication and neurosensory disorder of our expanding aging population, affecting hundreds of millions worldwide, and costing billions of dollars annually for management and interventions. Clinical interventions are particularly challenging in many ways, because the mechanisms of ARHL are not clear. This proposal is highly innovative because it aims to carry out translational research for new breakthrough strategies, based upon links between age-related autophagy changes in the auditory system and the progression of ARHL. In ongoing experiments, we have found age-related accumulations of autophagy markers such as LC3 and p62 in the mammalian cochlea. Our in vivo turnover experiments showed that an autophagic flux stress may exist in autolysosomal formation steps. We also found that inhibition of autophagy flux decreased the membrane expressions of Na,K-ATPase (NKA) and sodium potassium chloride cotransporter (NKCC1) in the SV-cell line (SV-K1). These are the two key ion channels that maintain the endocochlear potential (EP) for normal hearing. Given our new findings, we hypothesis that aging may affect sensory, neural and metabolic aspects of the cochlea through age-related autophagic stress. Therefore, we propose to carry out step-by-step cellular mechanism studies to yield a comprehensive view of the role of autophagy in the aged cochlea. The aims of this proposal are threefold: First, we are going to determine whether autophagy stress is a general feature of hearing loss. Several autophagy inhibitors will be used to treat young adult CBA/CaJ mice and their hearing abilities and biomarker changes will be measured. Second, the functional roles of autophagy flux stress in the cochlea, including age-related apoptosis and SV-related ion channel activity will be investigated. Third, we will identify target step(s) in autophagic flux on which aging exerts influences in the cochlea, and explore original, feasible ways for future interventions for ARHL. This project is expected to provide novel insights into unknown areas of the biological mechanisms of ARHL, and resolve many of the mysteries that will not only fuel a better understanding of cochlear aging process, but will facilitate the development of more sophisticated and effective prevention and treatment options for ARHL.