Background: One proinflammatory property observed during endothelial cell activation is the expression of the neutrophil adhesion molecule E-selectin on the surface of endothelial cells. An important regulatory element in endothelial cell E-selectin expression is the nuclear localization of the transcription factor nuclear factor (NK)-kappa B, which binds to and affects the function of several genes encoding proteins mediating inflammation.
Methods and results: In this study, we investigated the ability of pyrrolidine dithiocarbamate (PDTC), an agent that inhibits the nuclear localization of NF-kappa B, to (1) block endothelial cell E-selectin expression in vitro in response to tumor necrosis factor (TNF)-alpha, interleukin (IL)-1, and lipopolysaccharide (LPS) and (2) reduce neutrophil infiltration in a rabbit model of systemic inflammation. As measured with the use of an enzyme-linked immunosorbent assay, TNF-alpha, IL-1, and LPS each induced a significant increase in surface expression of E-selectin in cultured human umbilical vein endothelial cells (HUVECs) compared with HUVECs treated with medium alone. In contrast, E-selectin surface expression was blocked in HUVECs pretreated with PDTC before TNF-alpha, IL-1, or LPS stimulation. NF-kappa B was present in HUVEC nuclei treated with TNF-alpha, whereas translocation of NF-kappa B to the nucleus was absent in TNF-alpha-treated HUVECs pretreated with PDTC. In vivo, rabbits pretreated with PDTC before LPS infusion showed significantly less neutrophil infiltration in the lungs, liver, and heart compared with animals infused with LPS alone. This correlated with a reduction in E-selectin expression in vivo.
Conclusions: Our data suggest that NF-kappa B regulation of gene expression in the vascular endothelium may be an important cellular mechanism in endothelial cell activation.