Cytokines reprogram airway sensory neurons in asthma

Abstract

Nociceptor neurons play a crucial role in maintaining the body's equilibrium by detecting and responding to potential dangers in the environment. However, this function can be detrimental during allergic reactions, since vagal nociceptors can contribute to immune cell infiltration, bronchial hypersensitivity, and mucus imbalance, in addition to causing pain and coughing. Despite this, the specific mechanisms by which nociceptors acquire pro-inflammatory characteristics during allergic reactions are not yet fully understood. In this study, we aimed to investigate the molecular profile of airway nociceptor neurons during allergic airway inflammation and identify the signals driving such reprogramming. Using retrograde tracing and lineage reporting, we identified a class of inflammatory vagal nociceptor neurons that exclusively innervate the airways. Using an ovalbumin mouse model of airway inflammation, we found that these neurons undergo significant reprogramming characterized by the upregulation of the NPY receptor Npy1r, along with Il6. A screening of asthma-driving cytokines revealed that IL-13 drives part of this reprogramming, including Npy1r overexpression via the JAK/STAT6 pathway, while IL-1β induces IL-6 expression and release. Additionally, we observed that sympathetic neurons release NPY in the bronchoalveolar fluid of asthmatic mice, which limits the excitability of nociceptor neurons. In summary, allergic airway inflammation reprograms airway nociceptor neurons to acquire a pro-inflammatory phenotype, characterized by the release of IL-6, while a compensatory mechanism involving NPY1R limits nociceptor neurons' activity.