Lung endothelial cells regulate pulmonary fibrosis through FOXF1/R-Ras signaling (Mouse II).

Pulmonary fibrosis results from dysregulated repair of damaged tissue caused by persistent injury of lung epithelium. Multiple cell types in the lung are involved in the process of repair. During lung fibrogenesis, normal endothelial cells (EC) are re-programmed into fibrosis-associated EC. Transcriptional factors that control re-programming are poorly understood. Using single cell RNA-sequencing of EC from donor and idiopathic pulmonary fibrosis (IPF) lungs, and lungs from bleomycin-treated mice, we identified endothelial transcription factors (TF) that were differentially expressed during fibrosis. Focusing on one of endothelial TF, FOXF1, we demonstrated that FOXF1 is decreased in EC within human IPF and mouse bleomycin-injured fibrotic lungs. Dissociated single-cell preparations from bleomycin treated both tamoxifen- induced deletion in endFoxf1+/- mice (n = 3; PdGFb-creER; foxf1fl/+ ) and control mice (n=3; foxf1fl/+) were enriched for endothelial cells by FACS for CD45 (hematopoietic) negative, CD31 (endothelial) positive cells after dissociation by proteases. RNA from endothelial cells were extracted.