An airway protection program revealed by sweeping genetic control of vagal afferents

Sensory neurons evoke a suite of defensive reflexes to ensure airway integrity. Dysfunction of laryngeal neurons is life-threatening, causing pulmonary aspiration, dysphagia, and choking, yet relevant sensory pathways remain poorly understood. Here, we discover rare throat-innervating neurons (~100 neurons/mouse) that guard the airways against assault. We used genetic tools that broadly cover a vagal/glossopharyngeal sensory neuron atlas to map, ablate, and control specific afferent populations. Optogenetic activation of vagal P2RY1 neurons evokes a coordinated airway defense program- apnea, vocal fold adduction, swallowing, and expiratory reflexes. Selective ablation of vagal P2RY1 neurons eliminates protective responses to laryngeal water and acid challenge. Anatomical mapping revealed numerous terminal morphologies in the larynx, with P2RY1 neurons forming corpuscular endings that appose laryngeal taste buds. Epithelial cells are primary airway sentinels that communicate with second-order P2RY1 neurons through ATP. These findings provide mechanistic insights into airway defense, and a general molecular/genetic roadmap for internal organ sensation by the vagus nerve. Single-neuron sequencing of murine vagal sensory ganglia感觉神经元可引发一系列防御反射以维持气道完整性。喉神经元功能障碍可危及生命，引发肺误吸（pulmonary aspiration）、吞咽困难（dysphagia）与窒息（choking），但目前学界对相关感觉通路的认知仍十分有限。本研究发现了一类罕见的喉支配神经元（每只小鼠约含100个此类神经元），可保护气道免受外界侵害。我们采用可覆盖迷走/舌咽感觉神经元全图谱的广谱遗传工具，对特定传入神经元群进行定位、消融与精准操控。光遗传（Optogenetic）激活迷走P2RY1神经元可触发一套协调统一的气道防御程序：包括呼吸暂停、声带内收、吞咽及呼气反射。选择性消融迷走P2RY1神经元可完全消除机体针对喉内水与酸性刺激的防御应答。解剖定位结果显示，喉内存在多种神经末梢形态，其中P2RY1神经元可形成与喉味蕾紧密毗邻的小体样末梢。上皮细胞作为气道的初级哨兵，可通过三磷酸腺苷（ATP）与二级P2RY1神经元进行信号通讯。本研究结果为气道防御机制提供了机制层面的新见解，同时为迷走神经（vagus nerve）介导的内脏感觉研究提供了一套通用的分子/遗传研究路线图。本研究还完成了小鼠迷走感觉神经节的单细胞测序。