Endotoxin-induced activation of the nuclear transcription factor kappa B and expression of E-selectin messenger RNA in hepatocytes, Kupffer cells, and endothelial cells in vivo

Abstract

Endotoxin causes neutrophil sequestration in the liver and severe vascular and parenchymal cell injury. Inducible adhesion molecules such as intercellular adhesion molecule-1 and selectins are involved in neutrophil recruitment to an inflammatory site in vivo. The objective of our study was to characterize the translocation of the nuclear factor kappa B (NF-kappa B) from the cytoplasm to the nucleus (NF-kappa B activation) during endotoxemia using the electrophoretic mobility shift assay and to investigate its role in regulation of E-selectin gene transcription in liver cells in vivo. Administration of 0.5 mg/kg Salmonella enteritidis endotoxin to male Fischer rats induced a drastic but transient activation of NF-kappa B at the whole liver level. Major subunits identified were p50 (NF-kappa B1), p65 (RelA), and c-Rel, but not p52 (NF-kappa B2). Isolation of liver cells from control animals induced substantial NF-kappa B activation in Kupffer cells and endothelial cells and minor activation in hepatocytes. One hour after endotoxin treatment in vivo, NF-kappa B was uniformly activated in all isolated cells. At 5 h, NF-kappa B activation was reduced to various degrees in all cell types, with hepatocytes showing only a moderate decrease. Northern blot analysis indicated no E-selectin mRNA in all control cells; however, at 1 h, endotoxin induced E-selectin gene transcription transiently in endothelial cells and in Kupffer cells but not in hepatocytes. These data support the hypothesis that NF-kappa B activation is important for E-selectin gene transcription in hepatic vascular lining cells. However, the fact that hepatic parenchymal cells, despite NF-kappa B activation do not express E- selectin mRNA, suggests that NF-kappa B activation alone is not sufficient for E-selectin gene transcription in vivo.