• Yolanda Olmos, Francisco J Sánchez-Gómez, Brigitte Wild, Nieves García-Quintans, Sofía Cabezudo, Santiago Lamas, and María Monsalve.
• 1 Fundación Centro Nacional de Investigaciones Cardiovasculares Carlos III , Madrid, Spain .
• Antioxid. Redox Signal. 2013 Nov 1;19(13):1507-21.

UnlabelledSirT1 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.AimsHere we investigated SirT1 regulation of antioxidant genes and the roles played by FoxO3a and PGC-1α in this regulation.ResultsWe 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.InnovationA unifying mechanism for SirT1 activities is suggested.ConclusionWe show that SirT1 regulation of antioxidant genes in vascular endothelial cells depends on the formation of a FoxO3a/PGC-1α complex.

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