Platelet-activating factor induces NF-kappa B activation through a G protein-coupled pathway.
The capability of platelet-activating factor (PAF) to induce transcription factor activation was examined. In stably transfected Chinese hamster ovary cells expressing the PAF receptor (CHO-PAFR), PAF stimulation resulted in the nuclear expression of a DNA binding activity with specificity to the kappa B sequence. The p50 and p65 proteins, constituents of the prototypic nuclear factor kappa B (NF-kappa B), were identified as components of the DNA protein complexes by antipeptide antibodies in gel supershift as well as UV cross-linking experiments. PAF induced an initial decrease and subsequent increase of cytoplasmic I kappa B alpha levels, accompanied by up-regulation of the I kappa B alpha messenger RNA, a feature of NF-kappa B activation. PAF-induced kappa B binding activity was detected within 15 min after agonist stimulation, peaked at 30-40 min, and remained detectable by 2.5 h. SR 27417, a PAF receptor antagonist, blocked PAF-induced kappa B binding activity but not that induced by tumor necrosis factor-alpha (TNF alpha). Cholera toxin treatment markedly reduced PAF-induced kappa B binding activity, whereas pertussis toxin had no significant inhibitory effect. Neither of the two toxins affected the kappa B binding activity induced by TNF alpha in the same cells. In addition to the CHO-PAFR cells, PAF stimulated kappa B binding activity in the murine P388D1 macrophage and the human ASK.0 B cell lines that express endogenous PAF receptors. These results imply a potential role of PAF in the regulation of gene expression through a G protein-coupled transcription factor activation pathway.
Kravchenko
V V
VV
Department of Immunology, Scripps Research Institute, La Jolla, CA 92037, USA.
Pan
Z
Z
Han
J
J
Herbert
J M
JM
Ulevitch
R J
RJ
Ye
R D
RD
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D016466:CHO Cells; D002460:Cell Line; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D006224:Cricetinae; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000378:metabolism*; D015870:Gene Expression; D006801:Humans; D007700:Kinetics; D008264:Macrophages; D051379:Mice; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000096:biosynthesis* / Q000378:metabolism; D009838:Oligodeoxyribonucleotides; D010972:Platelet Activating Factor / Q000378:metabolism / Q000494:pharmacology*; D010980:Platelet Membrane Glycoproteins / Q000096:biosynthesis / Q000502:physiology*; D011401:Promoter Regions, Genetic; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000378:metabolism; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D016328:NF-kappa B; D009838:Oligodeoxyribonucleotides; D010972:Platelet Activating Factor; D010980:Platelet Membrane Glycoproteins; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; C039351:platelet activating factor receptor; D004247:DNA; D019204:GTP-Binding Proteins