NF-kappa B mediates up-regulation of CFTR gene expression in Calu-3 cells by interleukin-1 beta

Inflammation of the airways is a major feature of the inherited disease cys tic fibrosis. Previous studies have shown that the pro-inflammatory cytokin es tumor necrosis factor alpha and interferon gamma reduce the expression o f the cystic fibrosis transmembrane conductance regulator (CFTR) gene (CFTR ) in HT-29 and T84 cells by acting post-transcriptionally. We have investig ated the effect of the pro-inflammatory peptide interleukin 1 beta (IL-1 be ta) on the expression of the CFTR in Calu-3 cells, IL-1 beta increased the production of CFTR mRNA in a dose- and time-dependent manner. Its action wa s inhibited by inhibitors of the NF-kappaB pathway, including N-acetyl-L-cy steine, pyrrolidine dithiocarbamate, and a synthetic cell-permeable peptide containing the NF-kappaB nuclear localization signal sequence. Gel shift a nalysis showed that IL-1 beta activated NF-kappaB in Calu-3 cells, and tran sfection experiments using p50 and RelA expressing vectors showed that exog enous transfected NF-kappaB subunits increased the concentration of CFTR mR NA. Gel shift analysis with antibody supershifting also showed that IL-1 be ta caused the binding of NF-kappaB to a kappaB-like response element at pos ition -1103 to -1093 in the CFTR 5'-flanking region. Transfection experimen ts using -2150 to +52 CFTR reporter gene constructs showed that the activit y of the CFTR promoter is enhanced by exogenous transfected NF-kappaB and I L-1 beta and that this enhancement is due, at least in part, to the -1103 t o -1093 kappaB site. We conclude that the intracellular signaling that; lea ds to increased CFTR mRNA in response to IL-1 beta in Calu-3 cells includes the binding of NF-kappaB to the -1103 kappaB element and a subsequent incr ease in CFTR promoter activity.