Induction of MMP-9 in normal human bronchial epithelial cells by TNF-alphavia NF-kappa B-mediated pathway

In this study, we determined whether the proinflammatory cytokines tumor ne crosis factor (TNF)-alpha and interleukin-1 beta contribute to the regulati on of matrix metalloproteinase (MMP)-9 in human bronchial epithelial cells and whether the induction of MMP-9 is regulated by the transcription factor nuclear factor (NF)-kappaB. We demonstrated that TNF-alpha induced MMP-9 a t both the protein and mRNA levels in human bronchial epithelial cells and that interleukin-1 beta did not. In contrast, induction of the tissue inhib itor of metalloproteinase-1 by TNF-alpha was less than that of interleukin- 1b. Increased expression of MMP-9 and NF-kappaB activation induced by TNF-a lpha were inhibited by pyrrolidine dithiocarbamate and N-acetyl-L-cysteine but were not inhibited by curcumin. These results suggest that TNF-alpha in duces the expression of MMP-9 in human bronchial epithelial cells and that this induction is mediated via the NF-kappaB-mediated pathway.