Heme oxygenase-1 gene expression by a glutathione depletor, phorone, mediated through AP-1 activation in rats.

This study shows that induction of heme oxygenase-1 (HO-1) gene expression by a glutathione (GSH) depletor, phorone, is inhibited by cycloheximide pretreatment and involves changes in c-jun, not c-fos, mRNA. Buthionine sulfoximine (BSO) enhanced markedly both c-jun and HO-1 gene expression evoked by phorone. Phorone dramatically increased AP-1 binding activity, which was blocked by unlabeled AP-1 oligonucleotide and abolished by anit-Jun antibodies, but not anti-Fos antibodies. In addition, pretreatment with dexamethasone, an inhibitor of AP-1 DNA binding, inhibited phorone-mediated HO-1 mRNA induction. These findings suggest that HO-1 induction by phorone is likely to involve in the activation of AP-1 (Jun/Jun) binding, which could be associating with GSH depletion.