Manganese superoxide dismutase induction by iron is impaired in Friedreich ataxia cells

FEBS Lett. 2001 Nov 30;509(1):101-5. doi: 10.1016/s0014-5793(01)03140-4.


Iron-mediated oxidative stress has been implicated in the pathology of the neurodegenerative disease Friedreich ataxia (FRDA). Here, we show that normal upregulation of the stress defense protein manganese superoxide dismutase (MnSOD) fails to occur in FRDA fibroblasts exposed to iron. This impaired induction was observed at iron levels in which increased activation of the redox-sensitive factor NF-kappaB was absent. Furthermore, MnSOD induction could only be partially suppressed by antioxidants. We conclude that an NF-kappaB-independent pathway that may not require free radical signaling is responsible for the reduction of MnSOD induction. This impairment could constitute both a novel defense mechanism against iron-mediated oxidative stress in cells with mitochondrial iron overload and conversely, an alternative source of free radicals that could contribute to the disease pathology.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Antioxidants / pharmacology
  • Apoptosis
  • Blotting, Western
  • Cell Nucleus / metabolism
  • Cells, Cultured
  • DNA, Complementary / metabolism
  • Dose-Response Relationship, Drug
  • Fibroblasts / metabolism
  • Free Radical Scavengers / pharmacology
  • Free Radicals / metabolism
  • Friedreich Ataxia / metabolism*
  • Humans
  • Iron / metabolism*
  • Mitochondria / metabolism
  • NF-kappa B / metabolism
  • Nucleic Acid Hybridization
  • Oxidation-Reduction
  • Oxidative Stress
  • Phenotype
  • RNA / metabolism
  • Superoxide Dismutase / metabolism*
  • Time Factors
  • Transcription, Genetic
  • Up-Regulation


  • Antioxidants
  • DNA, Complementary
  • Free Radical Scavengers
  • Free Radicals
  • NF-kappa B
  • RNA
  • Iron
  • Superoxide Dismutase