NF-kappaB is involved in the regulation of CD154 (CD40 ligand) expression in primary human T cells.
Cognate interactions between CD154 (CD40 ligand, CD40L) on activated T cells and its receptor CD40 on various antigen-presenting cells are involved in thymus-dependent humoral immune responses and multiple other cell-mediated immune responses. We have studied the regulation of CD154 expression in human T cells after activation with anti-CD3 and anti-CD28 antibodies or after pharmacological activation of protein kinase C with phorbol 12-myristate 13-acetate, and the calcium ionophore ionomycin. Under these conditions, transcription of the CD154 gene was rapidly induced without requiring de novo protein synthesis. Pharmacological inhibitors of NF-kappaB activation down-regulated CD154 mRNA and protein levels. Cyclosporin A, an inhibitor of NF-AT activation, acted similarly, and the effects of both inhibitors were additive. A potential NF-kappaB binding site is present within the CD154 promoter at positions -1190 to - 1181. In electrophoretic mobility shift assays, this sequence was specifically bound by NF-kappaB present in nuclear extracts from activated T cells. Furthermore, in transient co-transfection of Jurkat T cells, p65 activated the transcription of a reporter construct containing a multimer of this NF-kappaB binding site. These observations demonstrate a role of NF-kappaB transcription factors in the regulation of CD40L expression in activated primary human T cells.
Srahna
M
M
Laboratory for Experimental Hematology, University of Leuven, Belgium.
Remacle
J E
JE
Annamalai
K
K
Pype
S
S
Huylebroeck
D
D
Boogaerts
M A
MA
Vandenberghe
P
P
D000328:Adult; D001665:Binding Sites; D023201:CD40 Ligand / Q000096:biosynthesis / Q000235:genetics*; D002478:Cells, Cultured; D003513:Cycloheximide / Q000494:pharmacology; D016572:Cyclosporine / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology; D017930:Genes, Reporter; D006801:Humans; D020672:I-kappa B Proteins; D019169:Jurkat Cells; D008213:Lymphocyte Activation / Q000187:drug effects; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000502:physiology*; D009842:Oligopeptides / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D011480:Protease Inhibitors / Q000494:pharmacology; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D015533:Transcriptional Activation; D014162:Transfection
D004268:DNA-Binding Proteins; D020672:I-kappa B Proteins; D016328:NF-kappa B; C000606204:NFKBIA protein, human; D009842:Oligopeptides; D011480:Protease Inhibitors; D011500:Protein Synthesis Inhibitors; D012333:RNA, Messenger; C090535:benzyloxycarbonyl-isoleucyl-glutamyl(O-tert-butyl)-alanyl-leucinal; D000072000:NF-KappaB Inhibitor alpha; D023201:CD40 Ligand; D016572:Cyclosporine; D003513:Cycloheximide