PTEN-mediated senescence of lung epithelial cells drives ventilator-induced pulmonary fibrosis.

Rationale: Mechanical ventilation (MV), a life-saving intervention for acute respiratory distress syndrome (ARDS), may exacerbate pulmonary fibrosis (PF) through unclear mechanisms. Although Phosphatase and Tensin homolog (PTEN) suppresses chronic PF, its role in MV-induced PF remains unknown. This study will determine whether PTEN mediates MV-PF via lung epithelial cell senescence. Methods: Human lung epithelial cells exposed to hydrochloric acid (HCl) and mechanical stretch (48 hours) and a murine "two-hit" (HCl+MV) model (14-day observation) were used. PTEN's role was assessed via siRNA (in vitro) and knockout (in vivo). Single-cell transcriptomics analyzed senescence-associated secretory phenotype (SASP) and pathway enrichment. RG7388 (MDM2-P53 inhibitor) was administered to PTEN knockout mice to evaluate P53-mediated senescence. Results: HCl+MV induced epithelial-mesenchymal transition (EMT) and fibrosis in vitro and in vivo. PTEN knockout or knockdown attenuated these effects. Single-cell profiling indicated PTEN's role in EMT and fibrosis via cell senescence pathways, particularly in epithelial cells exhibiting imbalances in the SASP scores. Furthermore, our experiments confirmed that senescence activation during fibrosis was reversed by PTEN inhibition. RG7388 treatment in PTEN knockout mice implicated P53-mediated senescence in PTEN's regulatory role. Conclusions: Our study demonstrates that PTEN plays a pivotal role in MV-PF, by mediating pulmonary epithelial cell senescence. Future studies may focus on developing strategies to modulate PTEN activity and cell senescence to prevent or treat this devastating disease.