Altered p53 and NOX1 activity cause bioenergetic defects in a SCA7 polyglutamine disease model

Spinocerebellar ataxia type 7 (SCA7) is one of the nine neurodegenerative disorders caused by expanded polyglutamine (polyQ) domains. Common pathogenic mechanisms, including bioenergetics defects, have been suggested for these so called polyQ diseases. However, the exact molecular mechanism(s) behin...

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Veröffentlicht in:Biochimica et biophysica acta 2015-04, Vol.1847 (4-5), p.418-428
Hauptverfasser: Ajayi, Abiodun, Yu, Xin, Wahlo-Svedin, Carolina, Tsirigotaki, Galateia, Karlström, Victor, Ström, Anna-Lena
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Sprache:eng
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Zusammenfassung:Spinocerebellar ataxia type 7 (SCA7) is one of the nine neurodegenerative disorders caused by expanded polyglutamine (polyQ) domains. Common pathogenic mechanisms, including bioenergetics defects, have been suggested for these so called polyQ diseases. However, the exact molecular mechanism(s) behind the metabolic dysfunction is still unclear. In this study we identified a previously unreported mechanism, involving disruption of p53 and NADPH oxidase 1 (NOX1) activity, by which the expanded SCA7 disease protein ATXN7 causes metabolic dysregulation. The NOX1 protein is known to promote glycolytic activity, whereas the transcription factor p53 inhibits this process and instead promotes mitochondrial respiration. In a stable inducible PC12 model of SCA7, p53 and mutant ATXN7 co-aggregated and the transcriptional activity of p53 was reduced, resulting in a 50% decrease of key p53 target proteins, like AIF and TIGAR. In contrast, the expression of NOX1 was increased approximately 2 times in SCA7 cells. Together these alterations resulted in a decreased respiratory capacity, an increased reliance on glycolysis for energy production and a subsequent 20% reduction of ATP in SCA7 cells. Restoring p53 function, or suppressing NOX1 activity, both reversed the metabolic dysfunction and ameliorated mutant ATXN7 toxicity. These results hence not only enhance the understanding of the mechanisms causing metabolic dysfunction in SCA7 disease, but also identify NOX1 as a novel potential therapeutic target in SCA7 and possibly other polyQ diseases. •We studied the mechanisms underlying the metabolic dysfunction in a SCA7 polyQ model.•Decreased p53 levels and a 50% change in p53-regulated metabolic proteins were found.•NOX1, but not NOX2, levels were induced 2 fold in SCA7 cells.•The altered p53 and NOX1 activity caused reduced mitochondrial OxPhos and ATP levels.•Reversal of p53 or NOX1 activity restored the metabolic phenotype and viability in SCA7 cells.
ISSN:0005-2728
0006-3002
1879-2650
1879-2650
DOI:10.1016/j.bbabio.2015.01.012