Oxalomalate, a Competitive Inhibitor of NADP+-dependent Isocitrate Dehydrogenase, Enhances Lipid Peroxidation-Mediated Oxidative Damage in U937 Cells

Arch Biochem Biophys. 2003 Aug 1;416(1):31-7. doi: 10.1016/s0003-9861(03)00291-1.

Abstract

Membrane lipid peroxidation processes yield products that may react with DNA and proteins to cause oxidative modifications. Cytosolic NADP+-dependent isocitrate dehydrogenase (ICDH) in U937 cells produces NADPH, an essential reducing equivalent for the antioxidant system. The protective role of ICDH against lipid peroxidation-mediated oxidative damage in U937 cells was investigated in control cells pre-treated with oxalomalate, a competitive inhibitor of ICDH. Upon exposure to 2,2'-azobis(2-amidinopropane) hydrochloride (AAPH) to U937 cells, which induces lipid peroxidation in membranes, the viability was lower and the protein oxidation, lipid peroxidation, and oxidative DNA damage, reflected by an increase in 8-hydroxy-2'-deoxyguanosine, were higher in oxalomalate-treated cells as compared to control cells. We also observed the significant increase in the endogenous production of reactive oxygen species, as measured by the oxidation of 2',7'-dichlorodihydrofluorescin, as well as the significant decrease in the intracellular GSH level in oxalomalate-treated U937 cells upon exposure to AAPH. These results suggest that ICDH plays an important role as an antioxidant enzyme in cellular defense against lipid peroxidation-mediated oxidative damage through the removal of reactive oxygen species.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amidines / pharmacology
  • Cells, Cultured
  • Enzyme Inhibitors / pharmacology*
  • Glutathione / metabolism
  • Humans
  • Isocitrate Dehydrogenase / antagonists & inhibitors*
  • Isocitrate Dehydrogenase / metabolism*
  • Lipid Peroxidation / drug effects*
  • Lipid Peroxidation / physiology
  • Malondialdehyde / analysis
  • Malondialdehyde / metabolism
  • Microscopy, Confocal / methods
  • NADP / metabolism*
  • Organophosphorus Compounds / analysis
  • Organophosphorus Compounds / metabolism
  • Oxalates / pharmacology*
  • Oxidants / pharmacology
  • Oxidation-Reduction / drug effects
  • Oxidative Stress / drug effects
  • Pyrenes / analysis
  • Pyrenes / metabolism
  • U937 Cells

Substances

  • Amidines
  • Enzyme Inhibitors
  • Organophosphorus Compounds
  • Oxalates
  • Oxidants
  • Pyrenes
  • diphenyl-1-pyrenylphosphine
  • oxalomalic acid
  • Malondialdehyde
  • NADP
  • 2,2'-azobis(2-amidinopropane)
  • Isocitrate Dehydrogenase
  • isocitrate dehydrogenase (NADP+)
  • Glutathione