Contribution of CFTR to Alveolar Fluid Clearance by Lipoxin A4via PI3K/Akt Pathway in LPS-Induced Acute Lung Injury

Abstract

The lipoxins are the first proresolution mediators to be recognized and described as the endogenous “braking signals” for inflammation. We evaluated the anti-inflammatory and proresolution bioactions of lipoxin A4in our lipopolysaccharide (LPS-)induced lung injury model. We demonstrated that lipoxin A4significantly improved histology of rat lungs and inhibited IL-6 and TNF-αin LPS-induced lung injury. In addition, lipoxin A4increased alveolar fluid clearance (AFC) and the effect of lipoxin A4on AFC was abolished byCFTRinh-172(a specific inhibitor of CFTR). Moreover, lipoxin A4could increase cystic fibrosis transmembrane conductance regulator (CFTR) protein expressionin vitroandin vivo. In rat primary alveolar type II (ATII) cells, LPS decreased CFTR protein expression via activation of PI3K/Akt, and lipoxin A4suppressed LPS-stimulated phosphorylation of Akt. These results showed that lipoxin A4enhanced CFTR protein expression and increased AFC via PI3K/Akt pathway. Thus, lipoxin A4may provide a potential therapeutic approach for acute lung injury.