Fig. 3: Cellular composition of epithelial cells during normal and hyperoxia-impaired late murine lung development.

a A total of five clusters of epithelial cells were identified in developing lungs. Cell populations are colored as indicated by the legend. b UMAP plots showing expression of principal identifiers of different epithelial cell types. The intensity of expression is indicated by purple coloring. c Heatmap of top five most differentially expressed genes across epithelial clusters. The intensity of expression is indicated as specified by the color legend. d Violin plots depicting changes in gene expression of some normoxia (21% O₂, green) and hyperoxia-specific (85% O₂, red) genes in the two AT2 clusters at P14. e Representative images from fluorescent RNA in situ hybridization for AT2-Lyz1⁺ marker Lyz1 (white) and pan-AT2 marker Sftpc (red) in developing mouse lungs. Magnification: 40×. Scale bar = 40 µm. Three 14-days old animals/group were analyzed. f UMAP plots depicting cell identity in regard to developmental time points in normally (purple) and aberrantly (green) developing lung epithelium. The intensity of expression is indicated as specified by the color legend. g Selected hyperoxia-impacted signaling pathways in AT2 (purple) and AT2-Lyz1⁺ (pink) clusters, as identified by gene set enrichment analysis (GSEA). All terms are significantly enriched (adjusted p value < 0.05) and normalized enrichment scores (NES) are shown. NES values were computed by gene set enrichment analysis on fold change-ranked genes. Expression values in Heatmap and violin plots represent Z-score-transformed log(TP10k + 1) values. Expression levels in UMAP plots are presented as log(TP10k + 1) values. Log(TP10k + 1) corresponds to log-transformed UMIs per 10k.