Mitochondrial Phospholipid Hydroperoxide Glutathione Peroxidase Inhibits the Release of Cytochrome C From Mitochondria by Suppressing the Peroxidation of Cardiolipin in Hypoglycaemia-Induced Apoptosis

Biochem J. 2000 Oct 1;351(Pt 1):183-93. doi: 10.1042/0264-6021:3510183.

Abstract

Cytochrome c (cyt. c) is a proapoptotic factor that binds preferentially to cardiolipin (CL), a mitochondrial lipid, but not to cardiolipin hydroperoxide (CL-OOH). Cyt. c that had bound to CL liposomes was liberated on peroxidation of the liposomes by a radical. The generation of CL-OOH in mitochondria occurred before the release of cyt. c in rat basophile leukaemia (RBL)2H3 cells that had been induced to undergo apoptosis by exposure to hypoglycaemia with 2-deoxyglucose (2DG). The amount of cyt. c bound to CL prepared from the mitochondria of 2DG-treated cells was lower than that of untreated cells. The release of cyt. c was completely suppressed when the production of CL-OOH in mitochondria was inhibited by the overexpression of mitochondrial phospholipid hydroperoxide glutathione peroxidase (PHGPx). The fluorescence from CL-labelling dye (10-N-nonyl Acridine Orange) decreased on the induction of apoptosis by 2DG. However, no decrease in fluorescence was observed in PHGPx-overexpressing cells. Cyt. c was released from mitochondria that had been isolated from control cells on peroxidation by t-butylhydroperoxide, but no similar liberation of cyt. c from mitochondria isolated from mitochondrial PHGPx-overexpressing cells was observed. These findings suggest that the generation of CL-OOH in mitochondria might be a primary event that triggers the release of cyt. c from mitochondria in the apoptotic process in which mitochondrial PHGPx participates as an anti-apoptotic factor by preventing the formation of CL-OOH.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acridine Orange / analogs & derivatives*
  • Acridine Orange / metabolism
  • Animals
  • Apoptosis* / drug effects
  • Cardiolipins / metabolism*
  • Cytochrome c Group / metabolism*
  • Deoxyglucose / pharmacology
  • Fluorescence
  • Glutathione Peroxidase / genetics
  • Glutathione Peroxidase / metabolism*
  • Hypoglycemia / chemically induced
  • Hypoglycemia / metabolism
  • Hypoglycemia / pathology*
  • Intracellular Membranes / drug effects
  • Intracellular Membranes / enzymology
  • Intracellular Membranes / metabolism
  • Lipid Peroxidation* / drug effects
  • Liposomes / chemistry
  • Liposomes / metabolism
  • Malates / pharmacology
  • Mitochondria / drug effects
  • Mitochondria / enzymology
  • Mitochondria / metabolism*
  • Mitochondria / pathology
  • Oxidation-Reduction
  • Phospholipid Hydroperoxide Glutathione Peroxidase
  • Phospholipids / metabolism
  • Protein Binding / drug effects
  • Rats
  • Tumor Cells, Cultured
  • tert-Butylhydroperoxide / pharmacology

Substances

  • Cardiolipins
  • Cytochrome c Group
  • Liposomes
  • Malates
  • Phospholipids
  • N(10)-nonylacridine orange
  • diethyl malate
  • tert-Butylhydroperoxide
  • Deoxyglucose
  • Phospholipid Hydroperoxide Glutathione Peroxidase
  • Glutathione Peroxidase
  • Acridine Orange