The impact of influenza pulmonary infection and inflammation on vagal bronchopulmonary sensory neurons
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ABSTRACT: Influenza A virus (IAV) is rapidly detected in the airways by the immune system, with resident parenchymal cells and leukocytes orchestrating viral sensing and the induction of antiviral inflammatory responses. The airways are innervated by heterogenous populations of vagal sensory neurons which also play an important role in pulmonary defense. How these neurons respond to IAV respiratory infection remains unclear. Here, we use a murine model to provide the first evidence that vagal sensory neurons undergo significant transcriptional changes following a respiratory IAV infection. RNA sequencing on vagal sensory ganglia showed that IAV infection induced the expression of many genes associated with an antiviral and pro-inflammatory response
Project description:Airway integrity must be continuously maintained throughout life. Sensory neurons guard against airway obstruction and on a moment-by-moment basis, enact vital reflexes to maintain respiratory function. Decreased lung capacity is common and life-threatening across many respiratory diseases, and lung collapse can be acutely evoked by chest wall trauma, pneumothorax, or airway compression. Here, we characterize a neuronal reflex of the vagus nerve evoked by airway closure that leads to gasping. In vivo vagal ganglion imaging revealed dedicated sensory neurons that detect airway compression but not airway stretch. Vagal neurons expressing PVALB mediate airway closure responses, and innervate clusters of lung epithelial cells called neuroepithelial bodies (NEBs). Stimulating NEBs or vagal PVALB neurons evoked gasping in the absence of airway threats, while ablating NEBs or vagal PVALB neurons eliminated gasping to airway closure. Single-cell RNA sequencing revealed that NEBs uniformly express the mechanoreceptor PIEZO2, and targeted knockout of PIEZO2 in NEBs also eliminated responses to airway closure. NEBs are dispensable for the Hering-Breuer inspiratory reflex, indicating that discrete terminal structures detect airway closure and inflation. Like Merkel cells involved in touch sensation, NEBs are PIEZO2-expressing epithelial cells, and moreover, are critical for an aspect of lung mechanosensation. These findings expand our understanding of neuronal diversity in the airways, and reveal a dedicated vagal pathway that detects airway closure to help preserve respiratory function.
Project description:Mammalian airways and lungs are richly innervated by bronchopulmonary sensory neurons, the vast majority of which are derived from the vagal sensory ganglia. In the present study we set out to perform high coverage single cell RNA sequencing on a population of identified murine bronchopulmonary sensory neurons collected from the vagal sensory ganglia to better define the molecular expression profiles of these cell types. Given the importance of P2X2 in differentiating nodose from jugular sensory neurons, we further aimed to investigate the relationship between transcriptional expression of identified genes and P2X2 expression.
Project description: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.
Project description:Respiratory defensive behaviors, like coughing, play a crucial role in protecting the respiratory system, ensuring its integrity and optimal function. How these critical behaviors are regulated by sensory stimuli within the body remains largely unknown. Here, we show that the nucleus of the solitary tract (NTS) in mice, a key hub in the brain for processing internal sensory signals and mediating interoceptive processes, contains heterogenous neuronal populations that differentially control breathing. Within these subtypes, activation of tachykinin 1 (Tac1) neurons triggers a specific respiratory behavior. Our detailed characterization of respiratory defensive behaviors reveals that these responses are cough-like behaviors. Chemogenetic silencing or genetic ablation of Tac1 neurons significantly reduces cough-like behaviors induced by tussive challenges. These Tac1 neurons receive synaptic inputs from the bronchopulmonary chemosensory and mechanosensory neurons in the vagal ganglion, and directly integrate the medullary regions to control sequential phases of cough-like defensive behaviors. We propose that these Tac1 neurons are a key component of the airway-vagal-brain neural circuit that controls cough-like defensive behaviors in mice, and they coordinate the downstream modular circuits to elicit the sequential motor pattern of forceful expiratory responses.
Project description:We report that molecularly distinct populations of vagal sensory neurons would play a role in causing differences in metabolic homeostasis between the sexes.
Project description:Sensory functions of the vagus nerve are critical for specific aware perceptions and for monitoring visceral functions in the cardio-pulmonary and gastrointestinal systems. Here we present a comprehensive identification, classification, and validation of the neuron types in the neural crest (jugular) and placode (nodose) derived vagal ganglia by single cell transcriptomic (scRNA-seq) analysis. Our results reveal major differences between neurons derived from different embryonic origins. Jugular neurons exhibit fundamental similarities to the somatosensory spinal neurons, including major types such as C-low threshold mechanoreceptors (C-LTMRs), A-LTMRs, Aδ-nociceptors, cold-, and mechano-heat C-nociceptors. In contrast, the nodose ganglion contains 18 distinct types dedicated to surveying the physiological state of the internal body. Our results reveal a vast diversity of vagal neuron types including many previously unanticipated types as well as proposed types that are consistent with chemoreceptors, nutrient detectors, baroreceptors, and stretch and volume mechanoreceptors of the respiratory, gastrointestinal, and cardiovascular systems.
Project description:Vagal neurons are an incredibly heterogeneous population of sensory neurons that are important for homeostasis. We used single cell RNA sequencing (scRNA-seq) to interrogate their molecular diversity shortly after birth.