Impact of Pclaf/Paf knock-out on murine lung regeneration (scRNA-seq)

The spatiotemporal orchestration of lung stem/progenitor cells is essential for lung regeneration, of which failure leads to lung disease, including fibrosis. We sought to identify mechanisms controlling lung stem/progenitor cells during lung regeneration. We previously found that PCLAF/PAF/KIAA0101 remodels the DREAM complex for cell quiescence exit and cell proliferation. PCLAF is expressed explicitly in the pulmonary proliferative cells (PPC), along with the DREAM target genes. Pclaf expression and Pclaf-expressing cells were acutely increased upon lung injury. Intriguingly, Pclaf knock-out mice exhibited lung fibrosis with impaired alveolar regeneration, resulting from the loss of alveolar type I cells. The single-cell transcriptome and organoid analyses showed that Pclaf transactivated the DREAM target gene expression for alveolar type I cells repopulation from alveolar type 2 cells. Additionally, pharmacological mimicking of the Pclaf-mediated transcriptome markedly increased alveolar regeneration in vitro and in vivo, without neoplasia. Together, our study unveiled the pivotal roles of the PCLAF-DREAM axis in controlling stem/progenitor cell activation and cell lineage, further proposing the potentially viable option for lung regenerative medicine. After 1 week of bleomycin (1.35 U/kg) insitllation into Pclaf WT and Pclaf KO mice, lung epithelial cells (Cd31-/Cd45-/Epcam+) were isolated by FACS and subjected to generate single-cell RNA library.