Sp1 sites mediate activation of the plasminogen activator inhibitor-1 promoter by glucose in vascular smooth muscle cells

Yan Qun Chen, Ming Su, Rampyari Raja Walia, Qin Hao, Joseph W. Covington, Douglas E. Vaughan*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

164 Scopus citations

Abstract

This study was designed to characterize the direct effects of hyperglycemia on plasminogen activator inhibitor-1 (PAI-1) expression in cultured vascular smooth muscle cells. Glucose induced dose- and time- dependent increases of PAI-1 mRNA expression in rat aortic smooth muscle (RASM) calls in vitro. Using a series of luciferase reporter gene constructs containing PAI-1 5'-flanking sequence (from -6.4 kilobase to -42 base pairs (bp)) transfected into RASM, we found that glucose (25 mM) consistently induced a 4-fold increase in luciferase activity, with the response localized to sequence between -85 and -42 bp. Mutagenesis of two putative Sp1-binding sites located in the region of interest essentially obliterated the glucose- response. Electrophoretic mobility shift assays with radiolabeled oligonucleotides containing the two putative Sp1-binding sites from PAI-1 promoter and nuclear extracts from RASM cells revealed that glucose treatment markedly changed the mobility pattern of the major protein-DNA complexes. Supershift assay showed that transcription factor Sp1 was present in the complexes under control and hyperglycemic conditions. These results suggest that glucose regulates PAI-1 gene expression in RASM cells through an effect on two adjacent Sp1 sites located between -85 and -42 bp of the PAI-1 5'- flanking region and that the release of a transcriptional repressor from the Sp1 complexes may explain the activation of the PAI-1 gene under high glucose conditions in RASM cells.

Original languageEnglish (US)
Pages (from-to)8225-8231
Number of pages7
JournalJournal of Biological Chemistry
Volume273
Issue number14
DOIs
StatePublished - Apr 3 1998

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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