Figure 5. Identification of the proliferative lung EC subpopulation during the regeneration phase.

(A) UMAP of 5318 individual lung ECs isolated at 3 days after systemic LPS injury. (B) The GO terms indicate the enriched biological processes of proEC. P values are indicated on the left in a color scale. (C) The expression levels of representative marker genes are visualized by UMAP. The color bars in UMAP indicate gene expression level in log₂ scale. (D) Confocal images of RNA-FISH of mouse lung sections obtained at 3 days after LPS injury. The lung structures are shown in D by enhancing autofluorescence of lung tissues. The lung ECs express tdTomato (Td). The RNAs of Ccne1 were probed and labeled with gray. Scale bar: 20 μm. Nuclei were stained by DAPI. (E) The quantification of cell number of Td⁺/Ccne1⁺ cells in lung sections of mice at baseline, LPS 24 hours, LPS 2 days, and LPS 3 days. Data are shown as mean ± SE from 3 independent mice at different time points. ****P < 0.0001 compared with baseline by 1-way ANOVA. (F) Pseudo-time trajectory of devECs from baseline, LPS 6 hours, LPS 1 day, LPS 2 days, and proEC of LPS 3 days. Colored by time points of LPS treatment.