A cis-acting region regulates oxidized lipid-mediated induction of the human heme oxygenase-1 gene in endothelial cells

Academic Article

Abstract

  • Objective - Several proatherogenic agents including oxidized LDL and its major component, 13-hydroperoxyoctadecadienoic acid (13-HPODE), upregulate heme oxygenase-1 (HO-1). Our previous studies have demonstrated that 13-HPODE-mediated HO-1 induction occurs via transcriptional mechanisms. The purpose of this study was to evaluate the molecular regulation and identify the signaling pathways involved in 13-HPODE-mediated HO-1 induction in human aortic endothelial cells. Methods and Results - The half-life of HO-1 mRNA after stimulation with 13-HPODE was ≈1.8 hours. Antioxidants such as N-acetylcysteine, iron chelation with deferoxamine mesylate, and protein kinase C inhibition with Gö6976 blocked HO-1 induction. Using promoter constructs up to 9.1 kb, no significant reporter activity was observed in response to 13-HPODE. A 13-HPODE-inducible DNase I hypersensitive site was identified that maps to a region ≈10 to 11 kb from the transcription start site of the human HO-1 gene. Based on the DNase I analysis, a -11.6-kb human HO-1 promoter construct was generated and elicited a 2.5-fold increase in reporter activity, indicating that 13-HPODE-mediated human HO-1 induction requires, at least in part, sequences that reside between 9.1 and 11.6 kb of the human HO-1 promoter. Conclusions - Elucidation of the molecular mechanisms which control HO-1 gene expression will allow us to develop therapeutic strategies to enhance the cytoprotective potential of HO-1 in atherosclerosis.
  • Digital Object Identifier (doi)

    Author List

  • Hill-Kapturczak N; Voakes C; Garcia J; Visner G; Nick HS; Agarwal A
  • Start Page

  • 1416
  • End Page

  • 1422
  • Volume

  • 23
  • Issue

  • 8