Figure 6. Viral infection expands CEBPA-dependent plasticity in mature AT2 cells.

(A) Experimental timeline of tamoxifen injection (Tam, 3 mg), Sendai virus (SeV) or saline (PBS) administration, and lung harvest at 14 dpi (day post-infection). Confocal images of immunostained infected Cebpa mutant and littermate control lungs, showing mutant-specific activation of SOX9 and increase in KI67 near airways (aw) and lobe edges (inset; scale: 10 um). Scale: 100 um. (B) Confocal images of lungs in (A) showing increased KRT8 and CLDN4. Scale: 100 um (inset: 10 um). (C) Confocal images of lungs in (A) showing lineage-labeled HOPX+ cells with little LAMP3 (arrowhead). Scale: 10 um. (D) Quantification of (A), (B) and (C). Each symbol represents one mouse from littermate pairs (Student’s t-test). (E) Sc-multiome UMAPs of purified epithelial cells from infected Cebpa mutant and littermate control lungs color coded by cell type (left) and the corresponding percentages (right). Esc, escaper; prolif, proliferating. (F) Dot plot showing the lineage marker (Sun1GFP), Cebpa, and cell type markers. (G) Sc-multiome UMAP color coded for genotype (left) and feature plots of metagene scores (top) and representative genes (bottom). A published damage-associated transient progenitor (DATP) score¹⁸ marks KRT8/CLDN4+ cells. See Table S6 for raw data including metagene lists.