Airway hyperreactivity is a hallmark feature of asthma and can be precipitated by airway insults, such as ozone exposure or viral infection. A proposed mechanism linking airway insults to airway hyperreactivity is augmented cholinergic transmission. In the current study, we tested the hypothesis that acute potentiation of cholinergic transmission is sufficient to induce airway hyperreactivity. We atomized the cholinergic agonist bethanechol to neonatal piglets and forty-eight hours later measured airway resistance. Bethanechol-treated piglets displayed increased airway resistance in response to intravenous methacholine compared to saline-treated controls. In the absence of an airway insult, we expected to find no evidence of airway inflammation; however, transcripts for several asthma-associated cytokines, including IL17A, IL1A, and IL8, were elevated in the tracheas of bethanechol-treated piglets. In the lungs, prior bethanechol treatment increased transcripts for IFNγ and its downstream target CXCL10. These findings suggest that augmented cholinergic transmission is sufficient to induce airway hyperreactivity, and raise the possibility that cholinergic-mediated regulation of pro-inflammatory pathways might contribute.

Mainstay therapeutics are ineffective in some people with asthma, suggesting a need for additional agents. In the current study, we used vagal ganglia transcriptome profiling and connectivity mapping to identify compounds beneficial for alleviating airway hyperreactivity (AHR). As a comparison, we also used previously published transcriptome data from sensitized mouse lungs and human asthmatic endobronchial biopsies. All transcriptomes revealed agents beneficial for mitigating AHR; however, only the vagal ganglia transcriptome identified agents used clinically to treat asthma (flunisolide, isoetarine). We also tested one compound identified by vagal ganglia transcriptome profiling that had not previously been linked to asthma and found that it had bronchodilator effects in both mouse and pig airways. These data suggest that transcriptome profiling of the vagal ganglia might be a novel strategy to identify potential asthma therapeutics.

Summary Prolonged heat and sea salt aerosols pose a challenge for the mammalian airway, placing the protective airway surface liquid (ASL) at risk for desiccation. Thus, mammals inhabiting salt marshes might have acquired adaptations for ASL regulation. We studied the airways of the rice rat, a rodent that inhabits salt marshes. We discovered negligible Na + transport through the epithelial sodium channel (ENaC). In contrast, carbachol induced a large Cl − secretory current that was blocked by the calcium-activated chloride channel (CaCC) inhibitor CaCCinhi-A01. Decreased mRNA expression of α, β, and γ ENaC, and increased mRNA expression of the CaCC transmembrane member 16A, distinguished the rice rat airway. Rice rat airway cultures also secreted fluid in response to carbachol and displayed an exaggerated expansion of the ASL volume when challenged with 3.5% NaCl. These data suggest that the rice rat airway might possess unique ion transport adaptations to facilitate survival in the salt marsh environment.

Prolonged heat and sea salt aerosols pose a challenge for the mammalian airway, placing the protective airway surface liquid (ASL) at risk for desiccation.Thus, mammals inhabiting salt marshes might have acquired adaptations for ASL regulation. We studied the airways of the rice rat, a rodent that inhabits salt marshes. We discovered negligible Na + transport through the epithelial sodium channel (ENaC). In contrast, carbachol induced a large Clsecretory current that was blocked by the calcium-activated chloride channel (CaCC) inhibitor CaCCinh-A01. Decreased mRNA expression of a, b, and g ENaC, and increased mRNA expression of the CaCC transmembrane member 16A distinguished the rice rat airway. Rice rat airway cultures also secreted fluid in response to carbachol and displayed an exaggerated expansion of the ASL volume when challenged with 3.5% NaCl. These data suggest that the rice rat airway might possess unique ion transport adaptations to facilitate survival in the salt marsh environment.

Background Neuronal cell cultures are widely used in the field of neuroscience. Cell dissociation allows for the isolation of a desired cell type, yet the complexity that distinguishes the nervous system is often lost as a result. Thus, culturing neural tissues in ex vivo format provides a physiological context that more closely resembles the in vivo environment. Nodose ganglia neurons have been extensively studied both in dissociated form and acutely in slice format. However, methods to culture long-term ex vivo have not been established. New MethodWe developed a simple method to culture nodose ganglia neurons from neonatal pigs long-term in ex vivo format using an in-house media formulation derived from commercially available components. ResultsCultures were viable for approximately 12 months. mRNA expression for nestin, a marker of neural progenitor cells, was stable across time. Vasoactive intestinal peptide and tachykinin, markers of nodose neurons, showed either no statistically significant differences or decreased across time, respectively. mRNA expression for glia fibrillary acidic protein and myelin basic protein showed no statistically significant differences over time.Comparison with Existing Method(s) There are currently no methods that describe long-term culturing of porcine nodose ganglia. Further, the media formulation we developed is new and not previously reported. ConclusionsThe simple procedure we developed for culturing nodose ganglia will enable both short-term and long-term investigations aimed at understanding peripheral ganglia in vitro. It is also possible that the methods described herein can be applied to other animal models, adult samples, and other neural tissues.