UP-REGULATION OF VASCULAR ENDOTHELIAL GROWTH-FACTOR BY H2O2 IN RAT-HEART ENDOTHELIAL, CELLS

Hydrogen peroxide (H2O2) is a reactive oxygen species generated by sev eral metabolic pathways in mammalian cells. Endothelial cells are extr emely susceptible to oxidative stress. H2O2 has been reported to incre ase the permeability in these cells. Using rat heart endothelial cell culture as a model system, we examined the effect of H2O2 on the gene expression of vascular endothelial growth factor (VEGF), a potent mito gen of endothelial cells and a vascular permeability factor. By Northe rn blot analysis we found that VEGF mRNA responded to H2O2 in a dose-a nd time-dependent manner. The induction was superinduced by cyclohexim ide and blocked by actinomycin D. N-Acetylcysteine, a synthetic antiox idant, was able to suppress the induction. H7, a protein kinase C inhi bitor, could also block the induction. Electrophoretic mobility shift assay revealed an enhanced binding of transcription factors, AP-1 and NF-kappa B. Immunoblot analysis showed that the amount of secreted VEG F was elevated in the medium 4 h after H2O2 stimulation. Our results d emonstrate that VEGF gene expression is upregulated by H2O2 in these e ndothelial cells. (C) 1998 Elsevier Science Inc.