Targeting the airway epithelial cell clock in attenuating airway hyperresponsiveness associated with T2 asthma

Asthma is a highly rhythmic disease with increased airway sputum eosinophilia and decline in lung function (FEV1) observed early morning. We have previously shown that airway hyperresponsiveness (AHR) is regulated by the clock gene Reverbα. Using the Cre/Lox system, we developed mice lacking Reverbα in CCSP-expressing airway epithelial cells (cKO, Fig 1A). These mice were subjected to a 5-week regimen of thrice-weekly intranasal house dust mite (HDM) challenges followed by non-invasive lung function measurement at 6-hour intervals(DCP) and terminally measured invasively at 6-hour intervals (Flexivent). Comprehensive inflammatory cell analysis and lung histopathology were conducted. Lung tissue was subjected to single-nuclei RNA sequencing (snRNAseq). <fig><object-id>erj;66/suppl_69/PA2600/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig> WT mice showed rhythmic EF50, reduced by HDM but disrupted in cKO (Fig 1B). Terminal lung function evaluations indicated significant temporal variations in WT mice, which were absent in cKO mice (Fig 1C). WT mice treated with HDM demonstrated a time-of-day effect on peri-bronchial inflammation (Fig 1D) perhaps due to infiltration of immune cells mainly eosinophils (Fig 1E). SnRNAseq identified 17 distinct cell clusters (Fig 1F) with HDM exposure-induced upregulation of allergen-responsive genes in alveolar type II cells & altered gene expression in endothelial cells of cKO mice (Fig 1G). Our finding suggests AHR is modulated by the airway epithelial clock.