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: 9273635
• 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/9273635
• 关键词: Ablation; Acute; Afferent Neurons; Anatomy; Animals; Biology; Brain; Breathing; C Fiber; 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; Image-Guided Surgery; 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 calcium imaging; 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管道。在呼吸道内，迷走神经感觉神经元在潮式呼吸期间检测肺的机械拉伸，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，并采用遗传工具来映射，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（P2 RY 1，NPY 2 R）进行了基因标记，这些神经传入神经对呼吸产生强大而相反的影响（Cell，2015）。P2 RY 1神经元在很大程度上是快速传导纤维，其支配称为神经上皮体的肺内分泌细胞簇。迷走神经P2 RY 1神经元的光遗传刺激停止呼吸，使动物陷入呼气，而不会严重影响心率或胃压，这些也在迷走神经控制下。NPY 2 R神经元主要是辣椒素反应性C纤维，迷走神经NPY 2 R神经元的光遗传学激活导致快速和浅呼吸。基于这些结果，我们假设迷走神经P2 RY 1神经元介导Hering-Breuer吸气反射，而迷走神经NPY 2 R神经元参与肺防御。这些发现提出了关于气道中激活P2 RY 1和NPY 2 R神经元的感觉刺激的基本问题，这些神经元是否是正常呼吸所需的，以及这些神经元如何感知和识别气道提示。我们将使用P2 ry 1-ires-Cre和Npy 2 r-ires-Cre小鼠，以及用于体内成像、神经元消融和细胞特异性基因敲除的遗传方法来探测迷走神经P2 RY 1和NPY 2 R神经元的感觉生物学。在目的1中，我们开发了一种新的在体成像范式，涉及一个遗传编码的钙指标，迷走神经节，并将使用这种技术来查询迷走神经P2 RY 1和NPY 2 R神经元的特定响应特性。在目标2中，我们将通过控制白喉毒素介导的细胞消融选择性地消除P2 RY 1和NPY 2 R神经元，并确定对呼吸生理的影响。在目标3中，我们将探索特定细胞表面受体在迷走神经传入中的作用，使用在部分或全部迷走神经感觉神经元中缺乏Piezo 2或P2 RY 1的敲除小鼠。Piezo 2在一组气道神经支配的感觉神经元中大量表达，并且是介导气道机械感觉的一个方面的主要候选者。总之，这些研究应该提供深入了解细胞机制的激活和调节呼吸控制通路的外周线索。了解迷走神经中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。