S124 Single-cell transcriptomics identifies unique pathways regulating airway hyperresponsiveness via circadian regulator Rev-erba in airway epithelium

• DOI: 10.1136/thorax-2024-btsabstracts.129
• Publication Date: 2024-11-04T09:40:58Z
• Authors: A Chakraborty; J Cain; R Maidstone; V Deugi; K Krakowiak; N Begley; J Gibbs; H Durrington
• Keywords: Airway hyperresponsiveness

<h3>Introduction and Objectives</h3> Asthma exhibits diurnal variation, with symptoms worsening at night, coincident increased airway inflammation narrowing overnight. Our research has highlighted the role of molecular clock in regulating hyperresponsiveness (AHR), a critical feature asthma. This study aims to investigate how epithelial regulates AHR variation. <h3>Methods</h3> We used Cre-lox system generate mice specific deletion <i>Rev-erbα</i> CCSP-expressing cells (CCSP-Rev-erbα^-/-, cKO, figure 1A). These underwent 5-week thrice-weekly intranasal HDM challenge. Lung function was assessed non-invasively every 6 hours using Dual Chamber Plethysmography (DCP). Inflammatory cell analysis lung histology were performed. tissue, harvested hours, subjected nuclei isolation single-nuclei RNA sequencing (snRNAseq) Parse Bioscience WT v2 kit. Sequencing performed on Illumina NovaSeq6000 an average depth 68,023 reads per cell. <h3>Results</h3> DCP measurements Tidal mid-expiratory flow (EF50), rhythmic wild-type (WT) animals (PBS p=0.04, HDM-treated, p&lt;0.01), 1B. EF50 reduced HDM-treated compared PBS controls Rhythmic variation lost cKO (both HDM-treated) PBS-treated mice. Single-nuclei identified 19 clusters (figure 1C), more alveolar type II 1D). treatment elevated genes related allergic responses cells, including <i>Sftpd, Malt1, CD166, Tnfaip2</i>, <i>Il31ra</i> 1E) while <i>Foxp1</i> expression endothelial (lung regulator), <i>Prx+</i> (nerve interactions), <i>slc26a4</i> (ion channel regulator) 1F). GSE enriched KEGG2019 pathways (FDR&lt;0.05) revealed adherent junctions, vascular smooth muscle contraction, tight junction regulation, calcium signalling, cortisol, glutamatergic synapse non-immune subsets upon 1G) Notch signalling circadian entrainment being affected additionally 1H). <h3>Conclusions</h3> results suggest that responsiveness perhaps through Notch-mediated pathway controlling innervation.