title: Upstream stimulatory factor-2 mediates quercetin-induced suppression of PAI-1 gene expression in human endothelial cells.
abstract: The polyphenol quercetin (Quer) represses expression of the cardiovascular disease risk factor plasminogen activator inhibitor-1 (PAI-1) in cultured endothelial cells (ECs). Transfection of PAI-1 promoter-luciferase reporter deletion constructs identified a 251-bp fragment (nucleotides -800 to -549) responsive to Quer. Two E-box motifs (CACGTG), at map positions -691 (E-box1) and -575 (E-box2), are platforms for occupancy by several members of the c-MYC family of basic helix-loop-helix leucine zipper (bHLH-LZ) proteins. Promoter truncation and electrophoretic mobility shift/supershift analyses identified upstream stimulatory factor (USF)-1 and USF-2 as E-box1/E-box2 binding factors. ECs co-transfected with a 251 bp PAI-1 promoter fragment containing the two E-box motifs (p251/luc) and a USF-2 expression vector (pUSF-2/pcDNA) exhibited reduced luciferase activity versus p251/luc alone. Overexpression of USF-2 decreased, while transfection of a dominant-negative USF construct increased, EC growth consistent with the known anti-proliferative properties of USF proteins. Quer-induced decreases in PAI-1 expression and reduced cell proliferation may contribute, at least in part, to the cardioprotective benefit associated with daily intake of polyphenols.
authors.affiliation: Department of Medicine, University of Alabama at Birmingham, Alabama, USA.
authors.forename: Nélida C
authors.initials: NC
authors.lastname: Olave
authors.forename: Maximiliano H
authors.initials: MH
authors.lastname: Grenett
authors.forename: Martin
authors.initials: M
authors.lastname: Cadeiras
authors.forename: Hernan E
authors.initials: HE
authors.lastname: Grenett
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Higgins
mesh_terms: D002316:Cardiotonic Agents; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D015536:Down-Regulation / Q000187:drug effects / Q000235:genetics; D024721:E-Box Elements; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D016350:Leucine Zippers / Q000235:genetics; D010446:Peptide Fragments; D017395:Plasminogen Activator Inhibitor 1 / Q000096:biosynthesis / Q000235:genetics*; D011794:Quercetin / Q000494:pharmacology*; D051720:Upstream Stimulatory Factors / Q000502:physiology*
chemical_list: D002316:Cardiotonic Agents; D010446:Peptide Fragments; D017395:Plasminogen Activator Inhibitor 1; C497184:USF2 protein, human; D051720:Upstream Stimulatory Factors; D011794:Quercetin