Activation of nuclear factor-kappa B in cultured endothelial cells by increased glucose concentration: Prevention by calphostin C

Nuclear factor kappa B (NF kappa B) plays a pivotal role in early gene responses by promoting messenger RNA (mRNA) synthesis for various cell-adhesion molecules and inducible nitric oxide synthase. In this study, we examined whether increases in glucose concentration enhance NF kappa B expression in nuclear fractions of endothelial cells by using electrophoretic mobility shift assay. Bovine aortic endothelial cells (BAECs) were incubated in media containing 5.5-35 mM glucose. NF kappa B activity was increased as early as 1 h (peak activation at 2-4 h) after incubation with 35 mM glucose compared with 5.5 mM. Similar increases at 2 h of incubation were observed by using 25 but not 15 mM glucose. Glucose-induced NF kappa B activation was blocked by inhibiting nuclear translocation by using a peptide (SN-50) containing the nuclear-localization sequence of NF kappa B p50 linked to a membrane-permeable motif of the sequence for Kaposi fibroblast growth factor. Co-incubation with a selective protein kinase C (PKC) inhibitor, calphostin C, produced a concentration-dependent inhibition of glucose-induced NF kappa B activation. Thus NF kappa B activation is an early event in response to elevations in glucose, which may elicit multiple pathways contributing to the origin of hyperglycemia- or diabetes-induced endothelial cell injury.