Transcriptional regulation of the human interleukin 1beta gene by fibronectin: role of protein kinase C and activator protein 1 (AP-1).
Interleukin 1beta (IL-1beta) is a multifunctional polypeptide considered a key cytokine during inflammation. Fibronectin (FN), a matrix glycoprotein highly expressed in injured tissues, can induce expression of IL-1beta in human blood monocytic cells. Herein, we explore the intracellular signals and transcriptional mechanisms responsible for IL-1beta induction by FN using human promonocytic U937 cells transfected with the human IL-1beta promoter connected to a reporter gene. Exposure of transfected U937s to FN resulted in increased expression of the full-length IL-1beta promoter. This effect, mediated via the alpha5beta1 integrin, was associated with activation of mitogen-activated protein kinases (MAPKs) and was abolished by pre-treatment of cells with Calphostin C, a specific inhibitor of protein kinase C (PKC) activation. Deletion analysis and co-transfection studies using consensus activator protein 1 (AP-1) oligonucleotides suggested that an AP-1 site present in the 5' end of the IL-1beta promoter was involved in the FN-induced response. Finally, electrophoretic mobility shift assays showed that FN induced binding of AP-1, but not NF-kappaB. Together, these experiments demonstrate that FN binding to the alpha5beta1 integrin activates MAPK-dependent signal pathways, and results in the transcription of the IL-1beta promoter in U937 cells by activating PKC and inducing AP-1.
Roman
J
J
Pulmonary and Critical Care Division, Department of Medicine, Atlanta Veterans Affairs Medical Center and Emory University School of Medicine, Atlanta, Georgia, USA. roman-rodriguez.jesse@atlanta.va.gov
Ritzenthaler
J D
JD
Fenton
M J
MJ
Roser
S
S
Schuyler
W
W
D015152:Blotting, Northern; D015153:Blotting, Western; D002448:Cell Adhesion; D015500:Chloramphenicol O-Acetyltransferase / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D018274:Electroporation; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005353:Fibronectins / Q000378:metabolism* / Q000494:pharmacology; D017353:Gene Deletion; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D006801:Humans; D007375:Interleukin-1 / Q000235:genetics* / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology; D020935:MAP Kinase Signaling System; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D009281:Naphthalenes / Q000494:pharmacology; D009842:Oligopeptides / Q000494:pharmacology; D011233:Precipitin Tests; D011401:Promoter Regions, Genetic; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism; D017469:Receptors, Fibronectin / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D018808:Transcription Factor AP-1 / Q000502:physiology*; D014158:Transcription, Genetic; D014162:Transfection; D020298:U937 Cells
D004791:Enzyme Inhibitors; D005353:Fibronectins; D007375:Interleukin-1; D008070:Lipopolysaccharides; D016328:NF-kappa B; D009281:Naphthalenes; D009842:Oligopeptides; D012333:RNA, Messenger; D017469:Receptors, Fibronectin; D018808:Transcription Factor AP-1; C047981:arginyl-glycyl-aspartic acid; D015500:Chloramphenicol O-Acetyltransferase; D011493:Protein Kinase C; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; C058819:calphostin C; D013755:Tetradecanoylphorbol Acetate