HIF-1 attenuates Ref-1 expression in endothelial cells: reversal by siRNA and inhibition of geranylgeranylation

Vascul Pharmacol. Aug-Sep 2009;51(2-3):133-9. doi: 10.1016/j.vph.2009.05.005. Epub 2009 Jun 11.

Abstract

Redox factor-1 (Ref-1), a multifunctional protein with DNA repairing activities, plays a cytoprotective function by post-translational redox modification of numerous transcription factors, including hypoxia inducible factor-1 (HIF-1). In the present study, activation of HIF-1 by hypoxia and dimethyloxaloylglycine (DMOG), a hypoxia mimic, diminished Ref-1 mRNA and protein expression in human microvascular endothelial cells (HMEC-1). Similarly, adenoviral delivery of the stabilized form of HIF-1alpha decreased Ref-1 mRNA and protein levels. Accordingly, HIF-1alpha siRNA abolished the hypoxia-induced inhibition of Ref-1 expression, indicating the role of HIF-1 in down-regulation of Ref-1. Also, translocation of Ref-1 from nucleus to cytoplasm after HIF-1 activation was noted. Interestingly, we observed the restoration of Ref-1 expression in hypoxia by pharmacologically relevant doses of atorvastatin. This effect was dependent on the inhibition of protein geranylgeranylation, but not farnesylation, as only the inhibitor of the former but not the latter prenylation step restored the Ref-1 expression. The regulation of Ref-1 by statins may be considered as a novel mechanism of their beneficial effects on endothelium.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkyl and Aryl Transferases / antagonists & inhibitors
  • Amino Acids, Dicarboxylic / genetics
  • Amino Acids, Dicarboxylic / metabolism
  • Atorvastatin
  • Cell Hypoxia / genetics*
  • Cell Line
  • DNA Repair / physiology
  • DNA-(Apurinic or Apyrimidinic Site) Lyase / genetics*
  • DNA-(Apurinic or Apyrimidinic Site) Lyase / metabolism
  • Endothelial Cells / metabolism*
  • Gene Expression Regulation, Enzymologic*
  • Heptanoic Acids / pharmacology
  • Humans
  • Hydroxymethylglutaryl-CoA Reductase Inhibitors / metabolism
  • Hydroxymethylglutaryl-CoA Reductase Inhibitors / pharmacology
  • Hypoxia-Inducible Factor 1 / genetics
  • Hypoxia-Inducible Factor 1 / metabolism*
  • Hypoxia-Inducible Factor 1, alpha Subunit / genetics
  • Hypoxia-Inducible Factor 1, alpha Subunit / metabolism
  • Immunohistochemistry
  • Iron Chelating Agents / metabolism
  • Microvessels
  • Point Mutation
  • Prenylation / genetics
  • Protein Transport
  • Pyrroles / pharmacology
  • RNA Interference*
  • RNA, Messenger / metabolism
  • RNA, Small Interfering
  • Transduction, Genetic

Substances

  • Amino Acids, Dicarboxylic
  • Heptanoic Acids
  • Hydroxymethylglutaryl-CoA Reductase Inhibitors
  • Hypoxia-Inducible Factor 1
  • Hypoxia-Inducible Factor 1, alpha Subunit
  • Iron Chelating Agents
  • Pyrroles
  • RNA, Messenger
  • RNA, Small Interfering
  • Atorvastatin
  • Alkyl and Aryl Transferases
  • geranylgeranyltransferase type-I
  • APEX1 protein, human
  • DNA-(Apurinic or Apyrimidinic Site) Lyase
  • oxalylglycine