title: Molecular mechanisms of syndecan-4 upregulation by TNF-α in the endothelium-like EAhy926 cells.
abstract: Syndecan-4, a cell-surface heparan sulfate proteoglycan, can participate in inflammation and wound healing as a host defense molecule. Tumour necrosis factor (TNF)-α, one of the most potent proinflammatory cytokines, is known to upregulate syndecan-4 expression, but the precise mechanisms are unclear. To elucidate these mechanisms in detail, we examined syndecan-4 upregulation by TNF-α in the endothelium-like EAhy926 cell. Of the two putative nuclear factor kappa-B (NF-κB) binding sites in the syndecan-4 gene (SDC4) promoter, deletion or mutation of one or both sites significantly diminished the effects of TNF-α. Electrophoretic mobility shift assays showed that p65 and c-Rel, but not p50, bound to these NF-κB binding sites, whereas pull-down assays showed binding of all three NF-κB components. Chromatin immunoprecipitation assays clearly showed that p65 and phosphorylated p65, but not p50 or c-Rel, bound to the SDC4 promoter. An NF-κB inhibitor, p65 knockdown and a transcriptional elongation inhibitor completely blocked the effect of TNF-α on SDC4 promoter activity and significantly, but not completely, blocked that on SDC4 mRNA expression. These data suggest that NF-κB p65 could be a key mediator of syndecan-4 upregulation by TNF-α through two binding sites in the SDC4 promoter, but other NF-κB-p65 independent pathways might also be involved through transcriptional elongation.
authors.affiliation: Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya 461-8673, Japan.
authors.forename: Eriko
authors.initials: E
authors.lastname: Okuyama
authors.forename: Atsuo
authors.initials: A
authors.lastname: Suzuki
authors.forename: Moe
authors.initials: M
authors.lastname: Murata
authors.forename: Yumi
authors.initials: Y
authors.lastname: Ando
authors.forename: Io
authors.initials: I
authors.lastname: Kato
authors.forename: Yuki
authors.initials: Y
authors.lastname: Takagi
authors.forename: Akira
authors.initials: A
authors.lastname: Takagi
authors.forename: Takashi
authors.initials: T
authors.lastname: Murate
authors.forename: Hidehiko
authors.initials: H
authors.lastname: Saito
authors.forename: Tetsuhito
authors.initials: T
authors.lastname: Kojima
mesh_terms: D001665:Binding Sites / Q000235:genetics; D004004:Dichlororibofuranosylbenzimidazole / Q000494:pharmacology; D042783:Endothelial Cells / Q000378:metabolism; D055785:Gene Knockdown Techniques; D006801:Humans; D006822:Hybrid Cells; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism; D009570:Nitriles / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013450:Sulfones / Q000494:pharmacology; D053671:Syndecan-4 / Q000235:genetics*; D061805:Transcription Elongation, Genetic; D051996:Transcription Factor RelA / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*; D015854:Up-Regulation / Q000187:drug effects
chemical_list: C434003:3-(4-methylphenylsulfonyl)-2-propenenitrile; D016328:NF-kappa B; D009570:Nitriles; C498143:RELA protein, human; D012333:RNA, Messenger; C508304:SDC4 protein, human; D013450:Sulfones; D053671:Syndecan-4; D051996:Transcription Factor RelA; D014409:Tumor Necrosis Factor-alpha; D004004:Dichlororibofuranosylbenzimidazole
keywords: NF-κB; TNF-α; p65; syndecan-4; upregulation