Regulation of the versican promoter by the beta-catenin-T-cell factor complex in vascular smooth muscle cells

J Biol Chem. 2005 Apr 1;280(13):13019-28. doi: 10.1074/jbc.M411766200. Epub 2005 Jan 24.

Abstract

The proteoglycan versican is pro-atherogenic and central to vascular injury and repair events. We identified the signaling pathways and promoter elements involved in regulation of versican expression in vascular smooth muscle cells. Phosphatidylinositol 3-kinase inhibitor, LY294002, significantly decreased versican-luciferase (Luc) promoter activity and endogenous mRNA levels. We further examined the roles of protein kinase B and glycogen synthase kinase (GSK)-3beta, downstream effectors of phosphatidylinositol 3-kinase, in the regulation of versican transcription. Co-transfection of dominant negative and constitutively active protein kinase B constructs with a versican-Luc construct decreased and increased promoter activity, respectively. Inhibition of GSK-3beta activity by LiCl augmented accumulation of beta-catenin and caused induction of versican-Luc activity as well as versican mRNA levels. Beta-catenin has no DNA binding domain, therefore it cannot directly induce transcription of the versican promoter. Software analysis of the versican promoter revealed two potential binding sites for T-cell factors (TCFs), proteins that confer transcriptional activation of beta-catenin. Electrophoretic mobility shift and supershift assays revealed specific binding of human TCF-4 and beta-catenin to oligonucleotides corresponding to a potential TCF binding site in the versican promoter. In addition to binding assays, we directly assessed the dependence of versican promoter activity on TCF binding sites. Site-directed mutagenesis of the TCF site located -492 bp relative to the transcription start site markedly diminished versican-Luc activity. Co-transfection of TCF-4 with versican-Luc did not increase promoter activity, but addition of beta-catenin and TCF-4 significantly stimulated basal versican promoter activity. Our findings suggest that versican transcription is predominantly mediated by the GSK-3beta pathway via the beta-catenin-TCF transcription factor complex in smooth muscle cells, wherein such regulation contributes to the normal or aberrant formation of provisional matrix in vascular injury and repair events.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Aorta / cytology
  • Binding Sites
  • Cell Line, Tumor
  • Chondroitin Sulfate Proteoglycans / biosynthesis*
  • Chondroitin Sulfate Proteoglycans / genetics*
  • Chromones / pharmacology
  • Cytoskeletal Proteins / metabolism*
  • DNA / metabolism
  • DNA, Complementary / metabolism
  • DNA-Binding Proteins / metabolism*
  • Enzyme Inhibitors / pharmacology
  • Gene Deletion
  • Gene Expression Regulation*
  • Genes, Reporter
  • Glycogen Synthase Kinase 3 / metabolism
  • Glycogen Synthase Kinase 3 beta
  • Humans
  • Immunoblotting
  • Lectins, C-Type
  • Lithium Chloride / pharmacology
  • Luciferases / metabolism
  • Lymphoid Enhancer-Binding Factor 1
  • Models, Genetic
  • Morpholines / pharmacology
  • Muscle, Smooth, Vascular / cytology*
  • Myocytes, Smooth Muscle / cytology*
  • Oligonucleotides / chemistry
  • Phosphoinositide-3 Kinase Inhibitors
  • Promoter Regions, Genetic*
  • Protein Binding
  • Protein Serine-Threonine Kinases / metabolism
  • Protein Structure, Tertiary
  • Proto-Oncogene Proteins / metabolism
  • Proto-Oncogene Proteins c-akt
  • RNA / metabolism
  • RNA, Messenger / metabolism
  • Rats
  • Reverse Transcriptase Polymerase Chain Reaction
  • Signal Transduction
  • Trans-Activators / metabolism*
  • Transcription Factors / metabolism*
  • Transcription, Genetic
  • Transfection
  • Versicans
  • Wound Healing
  • beta Catenin

Substances

  • CTNNB1 protein, human
  • Chondroitin Sulfate Proteoglycans
  • Chromones
  • Ctnnb1 protein, rat
  • Cytoskeletal Proteins
  • DNA, Complementary
  • DNA-Binding Proteins
  • Enzyme Inhibitors
  • Lectins, C-Type
  • Lymphoid Enhancer-Binding Factor 1
  • Morpholines
  • Oligonucleotides
  • Phosphoinositide-3 Kinase Inhibitors
  • Proto-Oncogene Proteins
  • RNA, Messenger
  • Trans-Activators
  • Transcription Factors
  • VCAN protein, human
  • Vcan protein, rat
  • beta Catenin
  • Versicans
  • 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one
  • RNA
  • DNA
  • Luciferases
  • GSK3B protein, human
  • Glycogen Synthase Kinase 3 beta
  • Gsk3b protein, rat
  • Protein Serine-Threonine Kinases
  • Proto-Oncogene Proteins c-akt
  • Glycogen Synthase Kinase 3
  • Lithium Chloride