Sensory biology of respiratory control neurons in the vagus nerve

迷走神经呼吸控制神经元的感觉生物学

• 批准号: 9077705
• 负责人: STEPHEN Daniel LIBERLES
• 金额: $ 42.38万
• 依托单位: HARVARD MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-05-15 至 2020-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9077705
• 关键词: Ablation; Afferent Neurons; Animals; Biology; Brain; Breathing; C Fiber; Calcium; Capsaicin; Cell Surface Receptors; Cells; Collection; Confocal Microscopy; Coughing; Cues; Data; Diphtheria Toxin; Disease; Electrophysiology (science); Endocrine; Exhalation; Fiber; Ganglia; Genetic; Genetic Identity; Heart Rate; Image; Individual; Inflammation; Intervention; Irritants; Knock-in Mouse; Knockout Mice; Lung; Lung diseases; Maps; Measures; Mechanics; Mechanoreceptors; Mediating; Molecular; Molecular Analysis; Molecular Genetics; Mus; Neuroepithelial Bodies; Neurons; Operative Surgical Procedures; Pathway interactions; Peripheral; Peripheral Nervous System; Physiology; Population; Preparation; Process; Property; Reflex action; Reporter; Respiration; Respiratory physiology; Role; Secretory Cell; Sensory; Sensory Ganglia; Signal Transduction; Stimulus; Stomach; Stretching; Techniques; Touch sensation; Vagotomy; Vagus nerve structure; base; calcium indicator; cohort; defense response; genetic analysis; genetic approach; in vivo; in vivo imaging; insight; knockout gene; nerve supply; neuroregulation; novel; optogenetics; pressure; public health relevance; receptor; relating to nervous system; respiratory; respiratory gas; respiratory health; response; sensor; sensory stimulus; therapeutic target; tool

 DESCRIPTION (provided by applicant): The vagus nerve is a major conduit between lung and brain required for normal respiration. Within the airways, vagal sensory neurons detect mechanical stretch of the lung during tidal breathing, cues associated with inflammation and illness, and irritants that in some species evoke cough. However, molecular mechanisms by which vagal sensory neurons detect and encode respiratory stimuli remain poorly understood. In preliminary data, we used a molecular and genetic approach to classify sensory afferents in the airways, and adapted genetic tools to map, image, ablate, and functionally control vagal sensory neurons. We genetically tagged two sparse populations of vagal afferents (P2RY1, NPY2R) that exert powerful and opposing effects on breathing (Cell, 2015). P2RY1 neurons are largely fast-conducting a fibers that innervate clusters of pulmonary endocrine cells termed neuroepithelial bodies. Optogenetic stimulation of vagal P2RY1 neurons stops breathing, trapping animals in exhalation, without acutely impacting heart rate or gastric pressure, which are also under vagal control. NPY2R neurons are largely capsaicin-responsive C fibers, and optogenetic activation of vagal NPY2R neurons causes rapid and shallow breathing. Based on these results, we hypothesize that vagal P2RY1 neurons mediate the Hering-Breuer inspiratory reflex, while vagal NPY2R neurons are involved in pulmonary defense. These findings raise basic questions regarding the sensory stimuli in the airways that activate P2RY1 and NPY2R neurons, whether these neurons are required for normal respiration, and how these neurons sense and transduce airway cues. We will use P2ry1-ires-Cre and Npy2r-ires-Cre mice, and genetic approaches for in vivo imaging, neuron ablation, and cell-specific gene knockout to probe the sensory biology of vagal P2RY1 and NPY2R neurons. In Aim 1, we developed a new in vivo imaging paradigm in vagal ganglia that involves a genetically encoded calcium indicator, and will use this technique to query the specific response properties of vagal P2RY1 and NPY2R neurons. In Aim 2, we will selectively eliminate P2RY1 and NPY2R neurons by controlled diphtheria toxin-mediated cell ablation and determine the impact on respiratory physiology. In Aim 3, we will explore the roles of particular cell surface receptors in vagal afferents using knockout mice that lack Piezo2 or P2RY1 in some or all vagal sensory neurons. Piezo2 is abundantly expressed in a cohort of airway- innervating sensory neurons, and is a prime candidate to mediate an aspect of airway mechanosensation. Together, these studies should provide insights into cellular mechanisms underlying activation and modulation of breathing control pathways by peripheral cues. Understanding the sensory biology of respiratory control neurons in the vagus nerve may provide therapeutic targets for airway disease intervention.

 描述（由申请人提供）：迷走神经是正常呼吸所需的肺和脑之间的主要导管。在气道内，迷走神经感觉神经元检测潮式呼吸期间肺部的机械拉伸、与炎症和疾病相关的线索，以及在某些物种中引起咳嗽的刺激物。然而，迷走神经感觉神经元检测和编码呼吸刺激的分子机制仍然知之甚少。在初步数据中，我们使用分子和遗传方法对气道中的感觉传入进行分类，并采用遗传工具来绘制、成像、消融和功能控制迷走神经感觉神经元。我们对两个稀疏的迷走神经传入神经群（P2RY1、NPY2R）进行了基因标记，它们对呼吸产生强大而相反的影响（Cell，2015）。 P2RY1 神经元主要是快速传导纤维，支配称为神经上皮体的肺内分泌细胞簇。迷走神经 P2RY1 神经元的光遗传学刺激会停止呼吸，使动物陷入呼气状态，而不会严重影响同样受迷走神经控制的心率或胃压。 NPY2R 神经元主要是辣椒素反应性 C 纤维，迷走神经 NPY2R 神经元的光遗传学激活会导致快速而浅的呼吸。基于这些结果，我们假设迷走神经 P2RY1 神经元介导 Hering-Breuer 吸气反射，而迷走神经 NPY2R 神经元参与肺防御。这些发现提出了一些基本问题：气道中激活 P2RY1 和 NPY2R 神经元的感觉刺激、这些神经元是否是正常呼吸所必需的，以及这些神经元如何感知和转导气道信号。我们将使用 P2ry1-ires-Cre 和 Npy2r-ires-Cre 小鼠，以及体内成像、神经元消融和细胞特异性基因敲除的遗传方法来探讨迷走神经 P2RY1 和 NPY2R 神经元的感觉生物学。在目标 1 中，我们在迷走神经节中开发了一种新的体内成像范例，其中涉及基因编码的钙指示剂，并将使用该技术来查询迷走神经 P2RY1 和 NPY2R 神经元的特定反应特性。在目标 2 中，我们将通过受控白喉毒素介导的细胞消融选择性消除 P2RY1 和 NPY2R 神经元，并确定对呼吸生理学的影响。在目标 3 中，我们将使用部分或全部迷走神经感觉神经元中缺乏 Piezo2 或 P2RY1 的基因敲除小鼠来探索特定细胞表面受体在迷走神经传入中的作用。 Piezo2 在一组支配气道的感觉神经元中大量表达，并且是介导气道机械感觉方面的主要候选者。总之，这些研究应该可以深入了解外周信号激活和调节呼吸控制途径的细胞机制。了解迷走神经呼吸控制神经元的感觉生物学可能为气道疾病干预提供治疗靶点。