In vitro culture of basal-like cells from fibrotic peripheral lung tissue

Rationale: In idiopathic pulmonary fibrosis (IPF) atypical basal-like cells are present in the alveolar compartment. We recently cultured cells with distinct morphology, which readily grew from peripheral fibrotic lung tissue, but only rarely from non-fibrotic tissue. Intrigued by their disease-enriched outgrowth and unique morphology we aimed to characterize these cells under different culture conditions and confirm their identity in IPF tissue in vivo. Methods: Cells were cultured from fibrotic peripheral lung tissue in DMEM/10%FCS or Cnt-PR-A. Samples were analysed by single cell RNA sequencing (scRNA-seq), TaqMan-PCR, or immunofluorescence (IF). Results: A high proportion of cells expressed the basal cell markers cytokeratin (KRT) 5, KRT17, KRT14 and TP63 when cultured in DMEM/FCS. Furthermore, about 75% showed close transcriptomic similarity to the recently described aberrant basaloid cells, co-expressing mesenchymal markers. In Cnt-PR-A, basal cell marker expression increased, whereas that of mesenchymal makers decreased. KRT5+/KRT17+ basal-like cells were mainly located within honeycomb cysts in peripheral IPF tissue. Conclusion: We here cultured basal-like cells from peripheral fibrotic lung tissue. Dependent on the culture conditions, these cells show similarities to airway basal cells or to the recently described aberrant basaloid cells, suggesting that the cells microenvironment determines their characteristics and possibly their function. Supported by a Sinergia (CRSII3.160704) and project grant (310030_192536) by the Swiss National Research Foundation.