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: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: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: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: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:Energy homeostasis requires precise measurement of the quantity and quality of ingested food. The vagus nerve innervates the gut and can detect diverse interoceptive cues, but the identity of the key sensory neurons and corresponding signals that regulate food intake remains unknown. Here we use an approach for target-specific, single-cell RNA sequencing to generate a map of the vagal cell types that innervate the gastrointestinal tract. We show that unique molecular markers identify vagal neurons with distinct innervation patterns, sensory endings, and function. Surprisingly, we find that food intake is most sensitive to stimulation of mechanoreceptors in the intestine, whereas nutrient-activated mucosal afferents have no effect. Peripheral manipulations combined with central recordings reveal that intestinal mechanoreceptors, but not other cell types, potently and durably inhibit hunger-promoting AgRP neurons in the hypothalamus. These findings identify a key role for intestinal mechanoreceptors in the regulation of feeding.
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:While the inflammatory immune response of the lung to allergens and pathogens has been extensively studied, little is known about how sensory nerves change in response to an inflammatory insult within the organ they innervate. In our study we describe the collection of vagal sensory neurons innervating the mouse lung, labelled with a retrograde fluorescent tracer instilled into the airways, and the analysis of their transcriptomes by RNAseq. We also determined transcriptomes of the complete sensory ganglia (vagal, trigeminal, DRG) for comparison. We identified transcripts of genes exclusively expressed in vagal nerves, and not in any other sensory nerve type or any other organ. These include unique ion channels, G-protein coupled receptors and several transcripts of unknown function.