Mitochondrial Function and Energy Metabolism in Neuronal HT22 Cells Resistant to Oxidative Stress

Br J Pharmacol. 2014 Apr;171(8):2147-58. doi: 10.1111/bph.12549.


Background and purpose: The hippocampal cell line HT22 is an excellent model for studying the consequences of endogenous oxidative stress. Extracellular glutamate depletes cellular glutathione by blocking the glutamate/cystine antiporter system xc-. Glutathione depletion induces a well-defined programme of cell death characterized by an increase in reactive oxygen species and mitochondrial dysfunction.

Experimental approach: We compared the mitochondrial shape, the abundance of mitochondrial complexes and the mitochondrial respiration of HT22 cells, selected based on their resistance to glutamate, with those of the glutamate-sensitive parental cell line.

Key results: Glutamate-resistant mitochondria were less fragmented and displayed seemingly contradictory features: mitochondrial calcium and superoxide were increased while high-resolution respirometry suggested a reduction in mitochondrial respiration. This was interpreted as a reverse activity of the ATP synthase under oxidative stress, leading to hydrolysis of ATP to maintain or even elevate the mitochondrial membrane potential, suggesting these cells endure ineffective energy metabolism to protect their membrane potential. Glutamate-resistant cells were also resistant to oligomycin, an inhibitor of the ATP synthase, but sensitive to deoxyglucose, an inhibitor of hexokinases. Exchanging glucose with galactose rendered resistant cells 1000-fold more sensitive to oligomycin. These results, together with a strong increase in cytosolic hexokinase 1 and 2, a reduced lactate production and an increased activity of glucose-6-phosphate dehydrogenase, suggest that glutamate-resistant HT22 cells shuttle most available glucose towards the hexose monophosphate shunt to increase glutathione recovery.

Conclusions and implications: These results indicate that mitochondrial and metabolic adaptations play an important role in the resistance of cells to oxidative stress.

Keywords: cell death; fusion/fission; glycolysis; mitochondria; oxidative phosphorylation; oxidative stress.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium / metabolism
  • Cell Count
  • Cell Death / drug effects
  • Cell Death / physiology
  • Cell Respiration / drug effects
  • Cell Respiration / physiology
  • Deoxyglucose / pharmacology
  • Drug Resistance / physiology
  • Energy Metabolism / drug effects
  • Energy Metabolism / physiology*
  • Glucosephosphate Dehydrogenase / metabolism
  • Glutamic Acid / pharmacology
  • Glutathione / metabolism
  • Hexokinase / metabolism
  • Hippocampus / drug effects
  • Hippocampus / physiopathology*
  • Lactic Acid / metabolism
  • Mechanistic Target of Rapamycin Complex 1
  • Mice
  • Mitochondria / drug effects
  • Mitochondria / metabolism
  • Mitochondria / physiology*
  • Multiprotein Complexes / metabolism
  • Neurons / drug effects
  • Neurons / enzymology
  • Neurons / metabolism
  • Neurons / physiology*
  • Oligomycins / pharmacology
  • Oxidative Stress / physiology*
  • Oxygen Consumption / drug effects
  • Superoxides / metabolism
  • TOR Serine-Threonine Kinases / metabolism


  • Multiprotein Complexes
  • Oligomycins
  • Superoxides
  • Lactic Acid
  • Glutamic Acid
  • Deoxyglucose
  • Glucosephosphate Dehydrogenase
  • HK1 protein, mouse
  • Hexokinase
  • TOR Serine-Threonine Kinases
  • Mechanistic Target of Rapamycin Complex 1
  • Glutathione
  • Calcium