Mechanisms Underlying Carotid Body-dependent Sympathetic Activation by Chronic Intermittent Hypoxia

慢性间歇性缺氧引起颈动脉体依赖性交感神经激活的机制

• 批准号: 10409552
• 负责人: Nanduri R Prabhakar
• 金额: $ 45.36万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-04-15 至 2024-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10409552
• 关键词: Adenylate Cyclase; Affect; Autonomic Dysfunction; Biochemical; Biological; Biological Assay; Blood Pressure; Carotid Body; Cell membrane; Central Sleep Apnea; Chronic; Complex; Cyclic AMP; Data; Development; Exhibits; Exposure to; G-Protein-Coupled Receptors; Gases; Gene Deletion; Genetically Engineered Mouse; Glomus Cell; Goals; Hyperactivity; Hypoxia; Joints; Knockout Mice; Lead; Link; Mediating; Molecular; Mus; Nerve; Odorant Receptors; Patients; Peripheral; Persons; Physiological; Publications; Rattus; Receptor Activation; Receptor Signaling; Reflex action; Reporting; Respiratory Disease; Rodent; Rodent Model; Role; Signal Transduction; Sleep Apnea Syndromes; Techniques; Testing; Therapeutic; comorbidity; conditional knockout; cyclic-nucleotide gated ion channels; experience; experimental study; innovation; interest; member; neuromechanism; novel; olfactory receptor; response; therapeutic evaluation

Project Summary- Project 1 Sleep apnea (SA) is a highly prevalent respiratory disease affecting several million people in the USA alone. Chronic Intermittent Hypoxia (CIH) is a hallmark manifestation of SA. Patients with SA, and rodents exposed to CIH exhibit elevated sympathetic nerve activity, which has been implicated in causing autonomic co- morbidities. The overall goal of the Project 1 is to delineate peripheral neural mechanisms underlying CIH- induced sympathetic activation and assess its impact on blood pressure. A heightened carotid body (CB) chemo reflex has been implicated as a major driver of CIH-induced sympathetic activation and gaseous messenger H2S mediates CB hyperactivity by CIH. Project 1 seeks to determine how H2S causes the CB activation by CIH. We test the hypothesis that H2S acting on olfactory receptor 78 (Olfr78) in glomus cells initiates a complex signaling cascade, involving a cAMP-dependent increase in [Ca2+]I leading to CB hyperactivity by CIH. We test this possibility using a combination of physiological, biochemical and molecular biological approaches on rats and mice exposed to CIH as well as in mice exhibiting spontaneous sleep apnea, and primary cultures of CB glomus cells. Studies in AIM 1 assess the role of Olfr78 in CB activation by CIH. AIM 2 determines whether CB activation by CIH requires cAMP activation by Olfr78 by H2S. AIM 3 determines how cAMP leads to CB activation by CIH. Experiments in AIM 4, determines the importance of CB H2S-Olfr78 signaling in CB excitation and sympathetic activation in mice exhibiting sleep apnea. Major conceptual and technical innovations include: a) H2S acting through odorant receptors mediates CIH-evoked CB excitation with profound consequences on autonomic functions is conceptually novel and has not been explored beyond the preliminary data presented in this application, b) assessing the significance of findings from experimental rodent model of CIH in mice exhibiting natural sleep apnea; and c) development of novel techniques to generate CB specific deletion of genes of interest. Project 1 has tight thematic linkages to Projects 2, 3, and 4 and utilizes Core B facilities for: a) exposing rats and mice to CIH, b) obtaining genetically engineered mice, c) targeted deletion of genes, and d) biochemical and molecular biological assays. Members of the investigative team have long-standing experience and expertise with the proposed approaches and a track record of working together as evidenced by joint publications. Successful completion of Project 1 is anticipated to establish a novel role for Olfr78 in mediating biological actions of H2S, which might lead to therapeutic strategies targeting of H2S-Olfr78 signaling to block CB reflex-dependent sympathetic hyperactivity.

项目概要 - 项目 1 睡眠呼吸暂停 (SA) 是一种非常流行的呼吸系统疾病，仅在美国就有数百万人受到影响。 慢性间歇性缺氧（CIH）是 SA 的标志性表现。 SA患者和暴露的啮齿动物 CIH 表现出交感神经活动升高，这与引起自主神经协调有关 发病率。项目 1 的总体目标是描绘 CIH 背后的周围神经机制 诱导交感神经激活并评估其对血压的影响。颈动脉体增高 (CB) 化学反射被认为是 CIH 诱导的交感神经激活和气态反应的主要驱动因素。 信使 H2S 通过 CIH 介导 CB 过度活跃。项目 1 旨在确定 H2S 如何导致 CB 通过 CIH 激活。我们检验了 H2S 作用于血管球细胞中的嗅觉受体 78 (Olfr78) 的假设 启动复杂的信号级联反应，涉及 [Ca2+]I 的 cAMP 依赖性增加，导致 CB CIH 引起的多动症。我们结合生理、生化和分子来测试这种可能性 对暴露于 CIH 的大鼠和小鼠以及表现出自发睡眠的小鼠进行生物学方法 呼吸暂停和 CB 球细胞原代培养物。 AIM 1 的研究评估了 Olfr78 在 CB 激活中的作用 CIH。 AIM 2 确定 CIH 激活 CB 是否需要 H2S 激活 Olfr78 的 cAMP。目标3 决定 cAMP 如何通过 CIH 导致 CB 激活。 AIM 4中的实验，决定了CB的重要性 表现出睡眠呼吸暂停的小鼠 CB 兴奋和交感神经激活中的 H2S-Olfr78 信号传导。主要的 概念和技术创新包括： a) H2S 通过气味受体作用介导 CIH 诱发 对自主神经功能具有深远影响的 CB 激发在概念上是新颖的，并且尚未被研究。 在本申请中提供的初步数据之外进行了探索，b) 评估研究结果的重要性 来自表现出自然睡眠呼吸暂停的小鼠的 CIH 实验啮齿动物模型； c) 小说的开发 产生 CB 特异性删除感兴趣基因的技术。项目 1 与主题密切相关 项目 2、3 和 4 并利用核心 B 设施：a) 将大鼠和小鼠暴露于 CIH，b) 获得遗传信息 工程小鼠，c) 基因定向删除，d) 生化和分子生物学测定。会员 的调查团队对拟议的方法拥有长期的经验和专业知识，并且 联合出版物证明了合作的记录。项目1顺利完成 预计 Olfr78 在介导 H2S 生物作用中发挥新作用，这可能会导致 针对 H2S-Olfr78 信号传导阻断 CB 反射依赖性交感神经的治疗策略 多动症。