Late Breaking Abstract - Preceding allergic airway inflammation impacts epithelial differentiation processes in mouse lung-derived bronchial organoids

Remodelling processes within the airways involving different cell types resemble an essential feature of chronic asthma. The direct impact of allergic airway inflammation (AAI) on early differentiation and activation processes of bronchial epithelial cells is still poorly investigated which was therefore the aim of the present study. Bronchial lung organoids were generated from mouse lungs affected by a preceding house dust mite-induced AAI and healthy control mice. After several weeks of culture such organoids were analysed by flow cytometry, qPCR and single cell sequencing (scSeq). The morphological appearance of organoids differed between those derived from control and AAI mice, with a spherical appearance in the first and a budding-like shaped appearance in the latter group. Based on the presence of subtype-specific surface markers and mRNA expression levels, a lack of ciliated cells was detected in AAI-derived organoids, specifically proved by downregulation of genes like Tuba1a and Foxj1. This was paralleled by an increase in secretory cells as confirmed by high expression of Scgb1a1 in organoids derived from AAI mice. Subsequent scSeq confirmed these findings and further identified three distinct secretory/club cell populations which varied in their presence between the experimental groups. Further, cells expressing basal cell markers such as Krt5, Krt14 and Krt17 were more abundant in the control group while other epithelial cell progenitor markers such as Pdpn, Trp63 and Itga6 appeared to be upregulated under AAI conditions. Thus, AAI significantly impacts early epithelial differentiation processes ideally to be investigated using lung organoids.