Delayed treatment with diethyl maleate prevents E-selectin expression in human endothelial cells

Background. Polymorphonuclear leukocyte (PMN) infiltration is a significant contributor to tissue damage in many disease states and is known to occur through an orderly set of events. The endothelial cell adhesion molecule E- selection is involved in the initial rolling of PMNs on the endothelium at sites of inflammation. We have previously shown that the glutathione deplet ing agent diethyl maleate (DEM) attenuates lung injury in a rodent model of intratracheal LPS stimulation. Te hypothesized that DEM might attenuate E- selectin in LPS-treated human umbilical vein endothelial cells as a mechani sm underlying this effect. Further, we investigated the role of delayed tre atment with DEM on E-selectin expression. Methods. Human umbilical vein endothelial cells were treated with DEM (100 to 400 mu mol/L) before of after LPS stimulation (1 mu g/mL). Surface expre ssion of E-selectin was examined using a cellular enzyme-linked immunosorbe nt assay. E-selectin mRNA transcripts were detected by Northern blot analys is. Nuclear factor-kappa B (NF-kappa B) activity was detected with gel shif t assays. Results. DEM significantly inhibited LPS-induced E-selectin surface express ion and mRNA levels in a dose-dependent fashion, with complete inhibition a t 250 mu mol/L, affecting cell viability. This inhibitory effect was seen e ven if DEM was added up to 60 minutes after LPS. DEM inhibited NF-kappa B n uclear translocation in a manner that mirrored protein and mRNA levels. Conclusion. Delayed treatment with DEM attenuates NF-kappa B nuclear transl ocation and E-selectin expression in human umbilical vein endothelial cells up to 60 minutes after the onset of LPS stimulation. Thus, DEM may represe nt an effective intervention for PMN-mediated organ injury even when given after an inflammatory insult.