p53 maintains lineage fidelity during lung capillary injury-repair in neonatal hyperoxia
Lisandra Vila Ellis, Jonathan D. Bywaters, Amanda Ceas, Yun Liu, Jennifer M.S. Sucre, Jichao Chen
Lisandra Vila Ellis, Jonathan D. Bywaters, Amanda Ceas, Yun Liu, Jennifer M.S. Sucre, Jichao Chen
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Research Article Development Pulmonology Vascular biology

p53 maintains lineage fidelity during lung capillary injury-repair in neonatal hyperoxia

Abstract

Bronchopulmonary dysplasia (BPD), a prevalent and chronic lung disease affecting premature newborns, results in vascular rarefaction and alveolar simplification. Although the vasculature has been recognized as a main player in this disease, the recently found capillary heterogeneity and cellular dynamics of endothelial subpopulations in BPD remain unclear. Here, we showed that Cap2 cells were damaged during neonatal hyperoxic injury, leading to their replacement by Cap1 cells, which, in turn, significantly declined. Single-cell RNA-Seq identified the activation of numerous p53 target genes in endothelial cells (ECs), including Cdkn1a (p21). While global deletion of p53 resulted in worsened vasculature, EC-specific deletion of p53 reversed the vascular phenotype and improved alveolar simplification during hyperoxia. This recovery was associated with the emergence of a transitional EC state, enriched for oxidative stress response genes and growth factors. Notably, this transitional EC gene signature was conserved in an aberrant capillary population identified in human BPD with pulmonary hypertension, underscoring the biological and clinical relevance of our findings. These results reveal a key role for p53 in maintaining endothelial lineage fidelity during pulmonary capillary repair following hyperoxic injury and highlight the critical contribution of the endothelium to BPD pathogenesis.

Authors

Lisandra Vila Ellis, Jonathan D. Bywaters, Amanda Ceas, Yun Liu, Jennifer M.S. Sucre, Jichao Chen

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Figure 4

Global p53 deletion in hyperoxia results in increased EC proliferation and Cap2-specific decrease.

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Global p53 deletion in hyperoxia results in increased EC proliferation a...
(A) En face view of immunostained lungs demonstrating efficient deletion of p53 in the hyperoxia p53-null condition compared with hyperoxia control by P21 staining. (B) En face view of immunostained lungs showing the effect of p53 deletion on total EC nuclei (ERG), Cap1 vasculature (PLVAP), and Cap2 vasculature (CAR4) in room air and hyperoxia, demonstrating a decrease in CAR4 staining in the hyperoxia p53-null group. (C) Quantification of Cap1 surface area, Cap2 surface area, and total vessel surface area (as measured by ICAM2 staining) in each condition (1-way ANOVA with Tukey’s multiple comparisons), demonstrating a significant reduction in Cap2 and total vessel area in the hyperoxia p53-null group. (D) Section immunostaining showing the effect of p53 deletion and hyperoxia treatment on cell proliferation (KI67) in ECs (ERG, white arrowheads) and non-ECs. (E) Quantification showing hyperoxia exposure or p53 deletion alone did not result in a significant increase in overall proliferation or EC proliferation compared with room air controls, but hyperoxia p53-null mice exhibited significant increases in both EC-specific and overall proliferation (1-way ANOVA with Tukey’s multiple comparisons). (F) Section immunostaining evaluating DNA damage (γH2AX) in hyperoxia-treated control and p53-null lungs. DNA damage is higher in hyperoxia p53-null lungs compared with hyperoxia controls, with sporadic colocalization of γH2AX to ECs (ERG) in the hyperoxia p53-null lung, indicating endothelial damage (white arrowheads). Boxed regions are shown at a higher magnification to the right. Images are representative of at least 3 littermate pairs. For quantification, each symbol represents the average of 3 distinct regions imaged within 1 mouse lung. m, macrophage. Scale bars: 10 μm.