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.

为这一提议进行的研究意义重大，因为它代表了对这一角色的第一次调查 因此，将产生关于新的信号通路的新的基本知识 与耳蜗机能有关。我们还将定义对听力健康影响的潜在安全顾虑 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。 食欲素是一个由两个肽组成的家族，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大脑各处。食欲素信号有缺陷 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 食欲素信号针对睡眠/觉醒行为的研究。利用免疫组织化学方法，我们证明了 食欲素前激素原和两种成熟的食欲素肽及其受体均在耳蜗处表达。我们 证明食欲素A/B前激素原基因缺失的小鼠(因此缺乏所有食欲素配体)不能康复 在野生型小鼠中引起典型TTS的噪声暴露后的ABR阈值。这是一个翻译过来的 重大发现，因为Ox1R和Ox2R是增食欲素受体拮抗剂药物的靶点，如 Suvorexant(BelSomra®)用于治疗失眠。在美国，大约30%的成年人报告有症状 在2013年美国疾病控制与预防中心的一项民意调查中，有4%的人报告说在2013年之前的一个月里使用了处方助眠药物。在帮助睡眠时 用于短期使用，通常用于较长时间(几个月到几年)。这是 尤其是老年人和患有许多其他疾病(创伤后应激障碍、焦虑、 等)。一个主要的问题是，使用食欲素靶向失眠药物是否存在潜在风险--做这些 药物会使患者面临听力障碍的风险，特别是如果持续服用会导致听力障碍 在未完全清除毒品的情况下？这项工作在翻译上更具相关性，因为睡眠辅助设备通常 由老年人使用，他们作为一个群体患有不正常的睡眠模式/失眠，而且通常 正在经历正常的年龄相关性听力障碍。我们这个项目的目标是：1)验证和扩展 我们用食欲素配体获得的初步数据表明，哪种受体(Ox1R、Ox2R或两者都)为空 在中等水平的声音暴露后导致听力损失；以及2)开始评估 观察到的功能障碍背后的机制与食欲素信号的丢失有关。我们将使用 形态(IHC下传入突触的免疫染色)、生理(ABR和 DPS)，以及蛋白质表达(细胞因子阵列)分析，以研究增食欲素信号在 噪声暴露后保持听力敏感度。我们还将研究噪声引起的局部 通过评估炎症状态和免疫细胞数评估耳蜗炎后的免疫反应 食欲素受体基因操作和噪声暴露后的耳蜗组织。