title: SirT1 regulation of antioxidant genes is dependent on the formation of a FoxO3a/PGC-1α complex.
abstract: SirT1 is a class III histone deacetylase that has been implicated in metabolic and reactive oxygen species control. In the vasculature it has been shown to decrease endothelial superoxide production, prevent endothelial dysfunction and atherosclerosis. However, the mechanisms that mediate SirT1 antioxidant functions remain to be characterized. The transcription factor FoxO3a and the transcriptional coactivator peroxisome proliferator activated receptor γ-coactivator 1α (PGC-1α) have been shown to induce the expression of antioxidant genes and to be deacetylated by SirT1.
  
  
  OBJECTIVE
  Here we investigated SirT1 regulation of antioxidant genes and the roles played by FoxO3a and PGC-1α in this regulation.
  
  
  RESULTS
  We found that SirT1 regulates the expression of several antioxidant genes in bovine aortic endothelial cells, including Mn superoxide dismutase (MnSOD), catalase, peroxiredoxins 3 and 5 (Prx3, Prx5), thioredoxin 2 (Trx2), thioredoxin reductase 2 (TR2), and uncoupling protein 2 (UCP-2) and can be localized in the regulatory regions of these genes. We also found that knockdown of either FoxO3a or PGC-1α prevented the induction of antioxidant genes by SirT1 over-expression. Furthermore, SirT1 increased the formation of a FoxO3a/PGC-1α complex as determined by co-immunoprecipitation (IP) assays, concomitantly reducing H2O2-dependent FoxO3a and PGC-1α acetylation. Data showing that FoxO3a knockdown increases PGC-1α acetylation levels and vice versa, suggest that SirT1 activity on FoxO3a and PGC-1α may be dependent of the formation of a FoxO3a/PGC-1α complex.
  
  
  METHODS
  A unifying mechanism for SirT1 activities is suggested.
  
  
  CONCLUSIONS
  We show that SirT1 regulation of antioxidant genes in vascular endothelial cells depends on the formation of a FoxO3a/PGC-1α complex.
authors: 1 Fundación Centro Nacional de Investigaciones Cardiovasculares Carlos III , Madrid, Spain .
authors: Yolanda
authors: Y
authors: Olmos
authors: Francisco J
authors: FJ
authors: Sánchez-Gómez
authors: Brigitte
authors: B
authors: Wild
authors: Nieves
authors: N
authors: García-Quintans
authors: Sofía
authors: S
authors: Cabezudo
authors: Santiago
authors: S
authors: Lamas
authors: María
authors: M
authors: Monsalve
mesh_terms: D000818:Animals; D000975:Antioxidants; D002374:Catalase / Q000235:genetics / Q000378:metabolism; D002417:Cattle; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism; D000071316:Forkhead Box Protein O3; D051858:Forkhead Transcription Factors / Q000378:metabolism*; D005786:Gene Expression Regulation; D007473:Ion Channels / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism; D018384:Oxidative Stress; D061105:Peroxiredoxin III / Q000235:genetics / Q000378:metabolism; D054464:Peroxiredoxins / Q000235:genetics / Q000378:metabolism; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D010766:Phosphorylation; D017382:Reactive Oxygen Species / Q000378:metabolism; D056564:Sirtuin 1 / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism; D054482:Thioredoxin Reductase 2 / Q000235:genetics / Q000378:metabolism; D013879:Thioredoxins / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*; D000071246:Uncoupling Protein 2
chemical_list: D000975:Antioxidants; D000071316:Forkhead Box Protein O3; D051858:Forkhead Transcription Factors; C474033:FoxO3 protein, mouse; D007473:Ion Channels; D024101:Mitochondrial Proteins; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; C485290:Ppargc1a protein, mouse; C516116:Prdx3 protein, mouse; D017382:Reactive Oxygen Species; D014157:Transcription Factors; C516112:Txn2 protein, mouse; C000604390:Ucp2 protein, mouse; D000071246:Uncoupling Protein 2; D013879:Thioredoxins; D061105:Peroxiredoxin III; D054464:Peroxiredoxins; C515975:Prdx5 protein, mouse; D002374:Catalase; D013482:Superoxide Dismutase; D054482:Thioredoxin Reductase 2; C516128:Txnrd2 protein, mouse; C470545:Sirt1 protein, mouse; D056564:Sirtuin 1