Effects of prostaglandin lipid mediators on agonist-induced lung endothelial permeability and inflammation

Abstract

Prostaglandins (PG), the products of cyclooxygenase-mediated conversion of arachidonic acid, become upregulated in many situations including allergic response, inflammation, and injury, and exhibit a variety of biological activities. Previous studies described barrier-enhancing and anti-inflammatory effects of PGE2 and PGI2 on vascular endothelial cells (EC). Yet, the effects of other PG members on EC barrier and inflammatory activation have not been systematically analyzed. This study compared effects of PGE2, PGI2, PGF2α, PGA2, PGJ2, and PGD2 on human pulmonary EC. EC permeability was assessed by measurements of transendothelial electrical resistance and cell monolayer permeability for FITC-labeled tracer. Anti-inflammatory effects of PGs were evaluated by analysis of expression of adhesion molecule ICAM1 and secretion of soluble ICAM1 and cytokines by EC. PGE2, PGI2, and PGA2 exhibited the most potent barrier-enhancing effects and most efficient attenuation of thrombin-induced EC permeability and contractile response, whereas PGI2 effectively suppressed thrombin-induced permeability but was less efficient in the attenuation of prolonged EC hyperpermeability caused by interleukin-6 or bacterial wall lipopolysaccharide, LPS. PGD2 showed a modest protective effect on the EC inflammatory response, whereas PGF2α and PGJ2 were without effect on agonist-induced EC barrier dysfunction. In vivo, PGE2, PGI2, and PGA2 attenuated LPS-induced lung inflammation, whereas PGF2α and PGJ2 were without effect. Interestingly, PGD2 exhibited a protective effect in the in vivo model of LPS-induced lung injury. This study provides a comprehensive analysis of barrier-protective and anti-inflammatory effects of different prostaglandins on lung EC in vitro and in vivo and identifies PGE2, PGI2, and PGA2 as prostaglandins with the most potent protective properties.