Protein kinase C-zeta mediates TNF-alpha-induced ICAM-1 gene transcriptionin endothelial cells

We addressed the role of protein kinase C (PKC) isozymes in mediating tumor necrosis factor-alpha (TNF-alpha)-induced oxidant generation in endothelia l cells, a requirement for nuclear factor-kappa B (NF-kappa B) activation a nd intercellular adhesion molecule-1 (ICAM-1) gene transcription. Depletion of the conventional (c) and novel (n) PKC isozymes following 24 h exposure of human pulmonary artery endothelial (HPAE) cells with the phorbol ester, phorbol 12-myristate 13-acetate (500 nM), failed to prevent TNF-alpha-indu ced oxidant generation. In contrast, inhibition of PKC-zeta synthesis by th e antisense oligonucleotide prevented the oxidant generation following the TNF-alpha stimulation. We observed that PKC-zeta also induced the TNF-alpha -induced NF-kappa B binding to the ICAM-1 promoter and the resultant ICAM-1 gene transcription. We showed that expression of the dominant negative mut ant of PKC-zeta prevented the TNF-alpha-induced ICAM-1 promoter activity, w hereas overexpression of the wild-type PKC-zeta augmented the response. The se data imply a critical role for the PKC-zeta isozyme in regulating TNF-al pha-induced oxidant generation and in signaling the activation of NF-kappa B and ICAM-1 transcription in endothelial cells.