Interferon enhances tumor necrosis factor-induced vascular cell adhesion molecule 1 (CD106) expression in human endothelial cells by an interferon-related factor 1-dependent pathway.
Tumor necrosis factor (TNF) and interleukin 1 are known to initiate endothelial vascular cell adhesion molecule (VCAM)-1 transcription primarily by activating nuclear factor (NF)-kappaB, which translocates to the nucleus. In addition to two NF-kappaB elements found within the minimal cytokine-inducible VCAM-1 promoter, an interferon-related factor (IRF) element (IRF-1) has been identified close to the transcription initiation site, suggesting that cytokines that induce IRF-1 might affect VCAM-1 expression levels. We therefore investigated the effects of interferons (IFNs), which strongly induce IRF-1, on VCAM-1 transcription and expression. We show that IFN-alpha and -gamma enhance TNF-induced VCAM-1 mRNA transcription and protein expression in human endothelial cells. IFN enhancement of TNF-induced expression is also seen using chloramphenicol acetyl transferase reporter genes linked to the minimal cytokine inducible VCAM-1 promoter. Nuclear IRF-1 is the molecular basis of IFN enhancement, because (a) IFN plus TNF-treated cells displayed increased nuclear IRF-1 levels and increased IRF-1 binding to the VCAM-1 promoter, compared with cells treated with TNF alone; (b) kinetics of nuclear IRF-1 levels correlated with VCAM-1 mRNA levels; (c) transfection with an IRF-1 construct substituted for IFN treatment; and (d) transfection with an expression construct encoding IRF-2, a competitive inhibitor of IRF-1, reduced TNF-induced VCAM-1 expression. Our experiments show that IFN amplifies TNF-induced VCAM-1 expression at the transcriptional level by an IRF-1-dependent pathway.
Lechleitner
S
S
Department of Dermatology, Division of General Dermatology, University of Vienna Medical School, Vienna, A-1090 Austria.
Gille
J
J
Johnson
D R
DR
Petzelbauer
P
P
D002451:Cell Compartmentation; D002467:Cell Nucleus / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D004347:Drug Interactions; D019040:E-Selectin / Q000096:biosynthesis; D004730:Endothelium, Vascular / Q000187:drug effects*; D017930:Genes, Reporter; D006801:Humans; D050856:Interferon Regulatory Factor-1; D007372:Interferons / Q000494:pharmacology*; D010750:Phosphoproteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012867:Skin / Q000098:blood supply; D014158:Transcription, Genetic; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D019010:Vascular Cell Adhesion Molecule-1 / Q000096:biosynthesis* / Q000235:genetics
D004268:DNA-Binding Proteins; D019040:E-Selectin; C494257:IRF1 protein, human; D050856:Interferon Regulatory Factor-1; D010750:Phosphoproteins; D014409:Tumor Necrosis Factor-alpha; D019010:Vascular Cell Adhesion Molecule-1; D007372:Interferons