The soluble factor milieu in IPF and in COPD exacerbations dysregulates epithelial differentiation

In idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD), epithelial abnormalities are present including bronchiolization and alveolar cell death and dysfunction. As epithelial progenitor cells are directed by their microenvironment, we hypothesized that changes in the microenvironment disrupt normal epithelial growth and differentiation. We therefore mimicked the soluble factor microenvironment in IPF using an IPF cocktail (IPFc), composed of 9 factors which are increased in IPF lungs (CCL2, IL-1β, IL-4, IL-8, IL-13, IL-33, TGF-β, TNFα and TSLP) and in COPD exacerbations using an exacerbation cocktail (EC) composed of 4 factors that are increased during an exacerbation of COPD (TNFα, IL-1β, IL-6, IL-8). We asked whether the soluble factor milieu in IPF and COPD exacerbations affects epithelial growth and differentiation. Mouse lung organoids (primary EpCAM+ cells co-cultured with CCL206 fibroblasts) were used to study epithelial growth and differentiation. Organoids exposed to IPFc, EC or TGF-β (as a comparator) were resorted into EpCAM+ and CCL206 fractions, and subjected to RNA-sequencing.