Impaired nuclear Nrf2 translocation undermines the oxidative stress response in Friedreich ataxia.
BACKGROUND
Friedreich ataxia originates from a decrease in mitochondrial frataxin, which causes the death of a subset of neurons. The biochemical hallmarks of the disease include low activity of the iron sulfur cluster-containing proteins (ISP) and impairment of antioxidant defense mechanisms that may play a major role in disease progression.


RESULTS
We thus investigated signaling pathways involved in antioxidant defense mechanisms. We showed that cultured fibroblasts from patients with Friedreich ataxia exhibited hypersensitivity to oxidative insults because of an impairment in the Nrf2 signaling pathway, which led to faulty induction of antioxidant enzymes. This impairment originated from previously reported actin remodeling by hydrogen peroxide.


CONCLUSIONS
Thus, the defective machinery for ISP synthesis by causing mitochondrial iron dysmetabolism increases hydrogen peroxide production that accounts for the increased susceptibility to oxidative stress.
Paupe
Vincent
V
Inserm, U676, Hôpital Robert Debré, Bât. Ecran, Paris, France.
Dassa
Emmanuel P
EP
Goncalves
Sergio
S
Auchère
Françoise
F
Lönn
Maria
M
Holmgren
Arne
A
Rustin
Pierre
P
D021581:Active Transport, Cell Nucleus; D000975:Antioxidants / Q000378:metabolism; D018450:Disease Progression; D005347:Fibroblasts / Q000378:metabolism; D005621:Friedreich Ataxia / Q000378:metabolism* / Q000473:pathology; D005786:Gene Expression Regulation; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D007506:Iron-Sulfur Proteins / Q000737:chemistry; D008954:Models, Biological; D051267:NF-E2-Related Factor 2 / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D015398:Signal Transduction
D000975:Antioxidants; D007506:Iron-Sulfur Proteins; D051267:NF-E2-Related Factor 2; C495635:NFE2L2 protein, human; D006861:Hydrogen Peroxide