The Hippo-YAP Pathway Regulates the Proliferation of Alveolar Epithelial Progenitors after Acute Lung Injury.

Regeneration of pulmonary epithelial cells plays an important role in the recovery of acute lung injury (ALI) which is defined by pulmonary epithelial cell death. However, the mechanism of the regenerative capacity of alveolar epithelial cells is unknown. Using a lung injury mouse model induced by hemorrhagic shock and LPS, a protein mass spectrometry-based high-throughput screening and linage tracing technology to mark alveolar epithelial type 2 cells (AEC2s), we analyzed the mechanism of alveolar epithelial cells proliferation. We demonstrated that the expression of Hippo-YAP1 (Yes-associated protein 1) key proteins were highly consistent with the regularity of the proliferation of alveolar epithelial type 2 cells after ALI. Furthermore, the results showed that YAP1-positive cells in lung tissue after ALI were mainly Sftpc lineage-labeled AEC2s. An in vitro proliferation assay of AEC2s demonstrated that AEC2 proliferation was significantly inhibited by both YAP1 siRNA and Hippo inhibitor. These findings revealed that YAP functioned as a key regulator to promote AEC2s proliferation, with the Hippo signaling pathway playing a pivotal role in this process.