PTTG1 promotes CD34+CD45+ cells to repair the pulmonary vascular barrier via activating the VEGF-bFGF/PI3K/AKT/eNOS signaling pathway in rats with phosgene-induced acute lung injury
Yu Dun, Hanbing Hu, Fuli Liu, Yiru Shao, Daikun He, Lin Zhang, Jie Shen
Abstract
Accidental exposure to phosgene can cause acute lung injury (ALI), characterized by uncontrolled inflammation and impaired lung blood-gas barrier. CD34+CD45+ cells with high pituitary tumor transforming gene 1 (PTTG1) expression were identified around rat pulmonary vessels through single-cell RNA sequencing, and have been shown to attenuate P-ALI by promoting lung vascular barrier repair. As a transcription factor closely related to angiogenesis, whether PTTG1 plays a role in CD34+CD45+ cell repairing the pulmonary vascular barrier in rats with P-ALI remains unclear. This study provided compelling evidence that CD34+CD45+ cells possess endothelial differentiation potential. Rats with P-ALI were intratracheally administered with CD34+CD45+ cells transfected with or without PTTG1-overexpressing and sh-PTTG1 lentivirus. It was found that CD34+CD45+ cells reduced the pulmonary vascular permeability and mitigated the lung inflammation, which could be reversed by knocking down PTTG1. Although PTTG1 overexpression enhanced the ability of CD34+CD45+ cells to attenuate P-ALI, no significant difference was found. PTTG1 was found to regulate the endothelial differentiation of CD34+CD45+ cells. In addition, knocking down of PTTG1 significantly reduced the protein levels of VEGF and bFGF, as well as their receptors, which in turn inhibited the activation of the PI3K/AKT/eNOS signaling pathway in CD34+CD45+ cells. Moreover, LY294002 (PI3K inhibitor) treatment inhibited the endothelial differentiation of CD34+CD45+ cells, while SC79 (AKT activator) yielded the opposite effect. These findings suggest that PTTG1 can promote the endothelial differentiation of CD34+CD45+ cells by activating the VEGF-bFGF/PI3K/AKT/eNOS signaling pathway, leading to the repair of the pulmonary vascular barrier in rats with P-ALI.