Oxidant-induced activation of nuclear factor-kappa B in cultured guinea pig gastric epithelial cells

The aim of this study was to reveal oxidant-sensitive components in gastric epithelial cells, which may regulate inflammatory processes in gastric mucosa. Gel mobility shift assay showed that treatment of cultured guinea pig gastric epithelial cells with hydrogen peroxide or diamide produced a KB oligonucleotide-protein complex within 5 min. The binding proteins consisted of a p50/p65 heterodimer, which was identified by immunosupershift, UV cross-linking, and immunoprecipitation analyses. Immunocytochemical study demonstrated that surface epithelial cells and parietal cells expressed p500 and p65 mainly in the cytosol, and the oxidants rapidly initiated the nuclear translocation of the components. The oxidants caused the up-regulation of p105 (a p50 precursor) synthesis and the expression of inducible nitric oxide synthase mRNA. These results suggest that the oxidant-sensitive p50/p65 heterodimer in gastric epithelial cells may play an important role in transcriptional activation of genes involved in inflammatory responses of the stomach.