Orexin Signaling in the Mouse Cochlea

小鼠耳蜗中的食欲素信号传导

• 批准号: 10598992
• 负责人: DOUGLAS E VETTER
• 金额: $ 23.25万
• 依托单位: UNIVERSITY OF MISSISSIPPI MED CTR
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-12-01 至 2024-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10598992
• 关键词: AMPA Receptors; Ablation; Adenylate Cyclase; Adult; Anxiety; Attenuated; Behavior; Brain; Cells; Cochlea; Code; Cyclic AMP-Dependent Protein Kinases; Data; Drug usage; Exposure to; Family; Feeding behaviors; Fiber; Functional disorder; Genes; Genetic; Glutamate Receptor; Glutamates; Goals; Growth; Hair Cells; Health; Hearing; Hypothalamic structure; Immune; Immune response; Immunohistochemistry; Individual; Infarction; Inflammation; Inflammatory; Inflammatory Response; Investigation; Ion Channel; Knockout Mice; Knowledge; Ligands; Link; Macrophage; Maintenance; Marketing; Mediating; Metabolic; Mind; Morphology; Mus; Narcolepsy; Nerve Fibers; Neurons; Neuropeptides; Noise; Noise-Induced Hearing Loss; Pain; Pathway interactions; Patients; Peptides; Peripheral; Persons; Pharmaceutical Preparations; Pharmacologic Substance; Physiological; Play; Population; Post-Traumatic Stress Disorders; Predisposition; Process; Proto-Oncogene Proteins c-akt; Pruritus; Recovery; Regulation; Reporting; Research; Risk; Role; Safety; Shapes; Signal Pathway; Signal Transduction; Sleep; Sleep Wake Cycle; Sleeplessness; Spinal Cord; Stains; Stroke; Supporting Cell; Symptoms; Synapses; System; Techniques; Time; Tissues; Wild Type Mouse; Work; age related; aged; antagonist; auditory stimulus; chemokine; cholinergic; cytokine; dorsal horn; drug clearance; experience; genetic manipulation; hearing impairment; hypocretin; immune cell infiltrate; immunoregulation; neural; neurotransmission; neurotransmitter release; noise exposure; novel; null mutation; orexin A; orexin B; permanent hearing loss; postsynaptic; preprohormone; protein expression; receptor; receptor expression; response; sleep abnormalities; sleep pattern; sound; theories; trafficking

The research undertaken for this proposal is significant because it represents the first investigation of the role of Orexin signaling in the cochlea and as such, will result in novel basic knowledge of a new signaling pathway related to cochlear function. We will also define potential safety concerns regarding impacts to hearing health associated with the use of an insomnia drug that is already used by a significant portion of the US population. The Orexins are a family of two peptides that in the brain are exclusively expressed in hypothalamic neurons. Both Orexin receptors, however, are widely dispersed throughout the brain. Defective Orexin signaling has been linked to sporadic nonfamilial narcolepsy, the most common form of narcolepsy, and therefore most research on Orexin signaling targets sleep/wake behavior. Using immunohistochemistry, we show that the Orexin pre-prohormone, both mature Orexins peptides, and their receptors are expressed in the cochlea. We demonstrate that Orexin A/B pre-prohormone gene null mice (thus lacking all Orexin ligands) do not recover ABR thresholds following noise exposures that induce classic TTS in wild type mice. This is a translationally significant finding because Ox1R and Ox2R are targets of Orexin receptor antagonist pharmaceuticals such as Suvorexant (Belsomra®) marketed to treat insomnia. Approximately 30% of adults in the US report symptoms of insomnia and 4% reported prescription sleep aid use in the month prior to a 2013 CDC poll. While sleep aids are meant for brief duration use, they are often used for long periods of time (months to years). This is especially true of aged individuals and those suffering from any of numerous other conditions (PTSD, anxiety, etc.). A major question is whether a latent risk exists in using Orexin-targeting insomnia medications- do these drugs leave patients at risk for hearing dysfunction, especially if taken consistently over time that would result in incomplete clearance of the drug? This work is further translationally relevant because sleep aids are often used by older individuals, who as a population suffer from abnormal sleep patterns/insomnia and also typically are experiencing normal age-related hearing dysfunction. Our goal for this project is to: 1) verify and expand our preliminary data obtained with Orexin ligand nulls by demonstrating which receptor (Ox1R , Ox2R, or both) contribute to the loss of hearing following moderate-level sound exposures; and 2) begin an assessment of the mechanisms underlying the observed dysfunction associated with loss of Orexin signaling. We will use a combination of morphological (immunostaining for afferent synapses under IHCs), physiological (ABRs and DPs), and protein expression (cytokine arrays) analyses to investigate the role of Orexin signaling in maintenance of hearing sensitivity following noise exposures. We will also examine the noise-induced local immune responses of the cochlea by assessing the inflammatory state and numbers of immune cells infiltrating the cochlea following Orexin receptor genetic manipulation and noise exposure.

针对该提案进行的研究意义重大，因为它代表了对该角色的首次调查 耳蜗中的食欲素信号传导，因此将产生新信号传导途径的新基础知识 我们还将定义与听力健康影响相关的潜在安全问题。 与使用一种已经被相当一部分美国人口使用的失眠药物有关。 食欲素是由两种肽组成的家族，在大脑中仅在下丘脑神经元中表达。 然而，这两种食欲素受体广泛分布在整个大脑中，导致食欲素信号传导缺陷。 与散发性非家族性发作性睡病有关，这是发作性睡病最常见的形式，因此大多数 通过免疫组织化学研究，食欲素信号传导针对睡眠/觉醒行为。 食欲素前激素原，都是成熟的食欲素肽，其受体在耳蜗中表达。 证明 Orexin A/B 前激素原基因缺失小鼠（因此缺乏所有 Orexin 配体）不会恢复 野生型小鼠暴露于噪声后诱导经典 TTS 的 ABR 阈值。 这是一项重大发现，因为 Ox1R 和 Ox2R 是食欲素受体拮抗剂药物的靶标，例如 Suvorexant (Belsomra®) 上市用于治疗失眠，大约 30% 的美国成年人有失眠症状。 2013 年 CDC 民意调查显示，4% 的人报告使用了处方助眠剂。 旨在短期使用，但通常会长期使用（数月至数年）。 对于老年人和患有多种其他疾病（创伤后应激障碍（PTSD）、焦虑症、 等等）。一个主要问题是使用针对食欲素的失眠药物是否存在潜在风险 - 是否这样做 患者使患者面临听力药物功能障碍的风险，特别是如果长期持续服用，会导致 这项工作具有进一步的转化相关性，因为睡眠辅助剂通常是 由老年人使用，他们作为一个群体患有异常的睡眠模式/失眠，并且通常也 正在经历与年龄相关的正常听力障碍。我们该项目的目标是：1）验证和扩展。 我们通过证明哪种受体（Ox1R、Ox2R 或两者）使用 Orexin 配体无效获得的初步数据 中等强度的声音暴露后会导致听力损失；2) 开始评估 我们将使用与食欲素信号丢失相关的观察到的功能障碍的机制。 形态学（IHC 下传入突触的免疫染色）、生理学（ABR 和 DP）和蛋白质表达（细胞因子阵列）分析，以研究 Orexin 信号传导在 噪声暴露后听力敏感性的维持 我们还将检查噪声引起的局部情况。 通过评估炎症状态和浸润的免疫细胞数量来评估耳蜗的免疫反应 食欲素受体基因操作和噪音暴露后的耳蜗。