Effect of glucocorticoids on the synthesis of antimicrobial peptides in amphibian skin

Gene-encoded peptide antibiotics are widespread in insects, plants and vertebrates and confer protection against bacterial and fungal infections, NF-kappa B is an important transcription factor for many immunity-related mammalian proteins and also for insect immune genes, The activity of NF-kappa B is regulated by the interaction,vith an inhibitor, I kappa B, It was recently demonstrated that glucocorticoids induce the synthesis of I kappa B in human cell lines, So far, all genes for peptide antibiotics have promoter motifs with NF-kappa B binding sites, but its actual function in peptide regulation has been studied only in insects, Here me show that glucocorticoid treatment of the frog Rana esculenta inhibits the transcription of all genes encoding antibacterial peptides by inducing the synthesis of I kappa B alpha. These results suggest that also in vertebrates peptide-mediated innate immunity is controlled by NF-kappa B-regulated transcription. (C) 1997 Federation of European Biochemical Societies.