Airway-derived p63+ facultative progenitors contribute to alveolar regeneration after lung injury.

Lung injury activates potential stem cells or progenitors for alveolar repair and regeneration. However, the activation program and source of injury-induced facultative progenitors remain incompletely known. Here, we find that lung injury induces emergence of p63-expressing progenitors, which rapidly proliferate and differentiate into alveolar type-1 (AT1) and type-2 (AT2) cells. scRNA-seq analysis uncovers that a subset of p63+ progenitors exhibit two distinct parallele transient stages before differentiation into mature AT1 and AT2 cells, respectively. Dual recombinases-mediated sequential genetic tracing reveals that facultative p63+ progenitors originate from the distal airway secretory cells and subsequently regenerate alveoli. Functioanlly, secretory cell-specific knockout of p63 significantly impairs their contribution to alveolar epithelium during lung regeneration. Our study identified secretory cell-derived facultative p63+ progenitors that contribute to alveolar regeneration, indicating a potential therapeutic target for lung treatment after injuires. Overall design: tdT+ and tdT- lung epithelial cell of the p63-CreER; R26-tdT mice were isolated by Fluorescence-activated cell sorting (FACS) and analyzed using scRNAseq.