Actin glutathionylation increases in fibroblasts of patients with Friedreich's ataxia: a potential role in the pathogenesis of the disease.
Increasing evidence suggests that iron-mediated oxidative stress might underlie the development of neurodegeneration in Friedreich's ataxia (FRDA), an autosomal recessive ataxia caused by decreased expression of frataxin, a protein implicated in iron metabolism. In this study, we demonstrate that, in fibroblasts of patients with FRDA, the cellular redox equilibrium is shifted toward more protein-bound glutathione. Furthermore, we found that actin is glutathionylated, probably as a result of the accumulation of reactive oxygen species, generated by iron overload in the disease. Indeed, high-pressure liquid chromatography analysis of control fibroblasts in vivo treated with FeSO4 showed a significant increase in the protein-bound/free GSH ratio, and Western blot analysis indicated a relevant rise in glutathionylation. Actin glutathionylation contributes to impaired microfilament organization in FRDA fibroblasts. Rhodamine phalloidin staining revealed a disarray of actin filaments and a reduced signal of F-actin fluorescence. The same hematoxylin/eosin-stained cells showed abnormalities in size and shape. When we treated FRDA fibroblasts with reduced glutathione, we obtained a complete rescue of cytoskeletal abnormalities and cell viability. Thus, we conclude that oxidative stress may induce actin glutathionylation and impairment of cytoskeletal functions in FRDA fibroblasts.
Pastore
Anna
A
Laboratory of Biochemistry, Children's Hospital and Research Institute Bambino Gesù, Piazza S. Onofrio 4, 00165 Rome, Italy.
Tozzi
Giulia
G
Gaeta
Laura Maria
LM
Bertini
Enrico
E
Serafini
Valentina
V
Di Cesare
Silvia
S
Bonetto
Valentina
V
Casoni
Filippo
F
Carrozzo
Rosalba
R
Federici
Giorgio
G
Piemonte
Fiorella
F
D000199:Actins / Q000378:metabolism*; D000975:Antioxidants / Q000494:pharmacology; D015153:Blotting, Western; D016022:Case-Control Studies; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D005260:Female; D005296:Ferrous Compounds / Q000494:pharmacology; D005347:Fibroblasts / Q000378:metabolism*; D005621:Friedreich Ataxia / Q000378:metabolism / Q000473:pathology*; D005978:Glutathione / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D008297:Male; D010084:Oxidation-Reduction; D012867:Skin / Q000737:chemistry / Q000473:pathology
D000199:Actins; D000975:Antioxidants; D005296:Ferrous Compounds; C020748:ferrous sulfate; D005978:Glutathione