Neuroprotection against neuroblastoma cell death induced by depletion of mitochondrial glutathione

Apoptosis. 2013 Jun;18(6):702-12. doi: 10.1007/s10495-013-0836-4.

Abstract

Mitochondrial glutathione pool is vital in protecting cells against oxidative stress as the majority of the cellular reactive oxygen species are generated in mitochondria. Oxidative stress is implicated as a causative factor in neuronal death in neurodegenerative disorders. We hypothesized that depletion of mitochondrial glutathione leads to mitochondrial dysfunction and apoptotic death of SK-N-SH (human neuroblastoma) cells and investigated the neuroprotective strategies against GSH depletion. SK-N-SH cells were treated with two distinct inhibitors of glutathione metabolism: L-buthionine-(S, R)-sulfoximine (BSO) and ethacrynic acid (EA). EA treatment caused depletion of both the total and mitochondrial glutathione (while BSO had no effect on mitochondrial glutathione), enhanced rotenone-induced ROS production, and reduced the viability of SK-N-SH cells. Glutathione depletion by BSO or EA demonstrated positive features of mitochondria-mediated apoptosis in neuroblastoma cell death. Prevention of apoptosis by Bcl2 overexpression or use of antioxidant ebselen did not confer neuroprotection. Co-culture with U-87 (human glioblastoma) cells protected SK-N-SH cells from the cell death. Our data suggest that depletion of mitochondrial glutathione leads to mitochondrial dysfunction and apoptosis. The study indicates that preventing mitochondrial glutathione depletion could become a novel strategy for the development of neuroprotective therapeutics in neurodegenerative disorders.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis / drug effects*
  • Apoptosis / physiology
  • Azoles / pharmacology
  • Buthionine Sulfoximine / pharmacology
  • Cell Line, Tumor
  • Cell Survival / drug effects
  • Coculture Techniques
  • Cytochromes c / metabolism
  • Cytosol / metabolism
  • Ethacrynic Acid / pharmacology
  • Glioblastoma / metabolism
  • Glioblastoma / pathology
  • Glutathione / metabolism*
  • Humans
  • Isoindoles
  • Mitochondria / drug effects*
  • Mitochondria / metabolism
  • Neuroblastoma / metabolism
  • Neuroblastoma / pathology
  • Neurons / physiology*
  • Organoselenium Compounds / pharmacology
  • Proto-Oncogene Proteins c-bcl-2 / metabolism
  • Reactive Oxygen Species / metabolism
  • bcl-2-Associated X Protein / metabolism

Substances

  • Azoles
  • Isoindoles
  • Organoselenium Compounds
  • Proto-Oncogene Proteins c-bcl-2
  • Reactive Oxygen Species
  • bcl-2-Associated X Protein
  • ebselen
  • Buthionine Sulfoximine
  • Cytochromes c
  • Glutathione
  • Ethacrynic Acid