title: Suppression of matrix metalloproteinase-9 transcription by transforming growth factor-beta is mediated by a nuclear factor-kappaB site.
abstract: TGF-beta (transforming growth factor-beta) plays a critical role in modulating the inflammatory response and other biological processes through its regulation of the production of MMPs (matrix metalloproteinases). In both Mono-Mac-6 and RAW264.7 monocyte/macrophage cells, TGF-beta abrogated lipopolysaccharide-induced increases in the enzymic activity and mRNA level of MMP-9. A fragment of the human MMP-9 promoter was used to characterize its regulation by TGF-beta signalling. In RAW264.7 cells, TGF-beta or its downstream signalling protein, Smad3 (Sma- and Mad-related protein 3), inhibited lipopolysaccharide-stimulated promoter activity. The suppressive activity of TGF-beta on the MMP-9 promoter was abrogated by an inhibitory Smad, Smad7. The MMP-9 promoter contains a putative TIE (TGF-beta inhibitory element). However, neither mutation nor deletion of the TIE had any effect on the inhibitory activity of TGF-beta on MMP-9 transcription, indicating that the consensus TIE is not required for this effect of TGF-beta. Analysis using a series of deletion mutants of the MMP-9 promoter revealed that a region containing a consensus NF-kappaB (nuclear factor-kappaB) site is required for the basal activity and TGF-beta-mediated suppression of the promoter. Mutation of the putative NF-kappaB site not only markedly reduced the basal transcriptional activity of the promoter, but also abrogated the responsiveness of the promoter to TGF-beta. In addition, a minimal promoter containing one copy of the NF-kappaB sequence was responsive to TGF-beta treatment. Furthermore, an electrophoretic mobility shift assay was performed with the nuclear extracts from RAW264.7 cells, and it was found that TGF-beta treatment did not disrupt the binding of NF-kappaB p50 and p65 proteins to the NF-kappaB sequence. Taken together, these studies indicate that the NF-kappaB site is indispensable for the suppressive activity of TGF-beta in the regulation of MMP-9 transcription.
authors.affiliation: Department of Medical and Molecular Genetics, Walther Oncology Center, Indiana University School of Medicine and the Walther Cancer Institute, Indianapolis, IN 46202, USA.
authors.forename: Kenji
authors.initials: K
authors.lastname: Ogawa
authors.forename: Feifei
authors.initials: F
authors.lastname: Chen
authors.forename: Chenzhong
authors.initials: C
authors.lastname: Kuang
authors.forename: Yan
authors.initials: Y
authors.lastname: Chen
mesh_terms: D001665:Binding Sites; D002460:Cell Line; D045744:Cell Line, Tumor; D005786:Gene Expression Regulation / Q000502:physiology*; D006801:Humans; D007948:Leukemia, Monocytic, Acute / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D008264:Macrophages / Q000737:chemistry / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000235:genetics* / Q000378:metabolism; D009000:Monocytes / Q000737:chemistry / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism / Q000502:physiology*; D052002:NF-kappa B p50 Subunit; D011401:Promoter Regions, Genetic / Q000502:physiology; D011485:Protein Binding; D015398:Signal Transduction / Q000502:physiology; D051996:Transcription Factor RelA; D014158:Transcription, Genetic / Q000502:physiology; D016212:Transforming Growth Factor beta / Q000378:metabolism / Q000502:physiology*
chemical_list: D016328:NF-kappa B; D052002:NF-kappa B p50 Subunit; D051996:Transcription Factor RelA; D016212:Transforming Growth Factor beta; D020780:Matrix Metalloproteinase 9