SIRT1 deficiency downregulates PTEN/JNK/FOXO1 pathway to block reactive oxygen species-induced apoptosis in mouse embryonic stem cells

Stem Cells Dev. 2011 Jul;20(7):1277-85. doi: 10.1089/scd.2010.0465. Epub 2011 Jan 3.

Abstract

Silent mating type information regulation 2 homolog 1 (SIRT1) plays a critical role in reactive oxygen species-triggered apoptosis in mouse embryonic stem (mES) cells. Here, we investigated a possible role for the PTEN/Akt/JNK pathway in the SIRT1-mediated apoptosis pathway in mES cells. Akt was activated by removal of anti-oxidant 2-mercaptoethanol in SIRT1(-/-) mES cells. Since PTEN is a negative regulator of Akt and its activity can be modulated by acetylation, we investigated if SIRT1 deacetylated PTEN to downregulate Akt to trigger apoptosis in anti-oxidant-free culture conditions. PTEN was hyperacetylated and excluded from the nucleus in SIRT1(-/-) mES cells, consistent with enhanced Akt activity. SIRT1 deficiency enhanced the acetylation/phosphorylation level of FOXO1 and subsequently inhibited the nuclear localization of FOXO1. Cellular acetylation levels were enhanced by DNA-damaging agent, not by removal of anti-oxidant. c-Jun NH2-terminal kinase (JNK) was activated by removal of anti-oxidant in SIRT1-dependent manner. Although p53 acetylation was stronger in SIRT1(-/-) mES cells, DNA-damaging stress activated phosphorylation and enhanced cellular levels of p53 irrespective of SIRT1, whereas removal of anti-oxidant slightly activated p53 only with SIRT1. Expression levels of Bim and Puma were increased in anti-oxidant-free culture conditions in an SIRT1-dependent manner and treatment with JNK inhibitor blocked induction of Bim expression. DNA-damaging agent activated caspase3 regardless of SIRT1. Our data support an important role for SIRT1 in preparing the PTEN/JNK/FOXO1 pathway to respond to cellular reactive oxygen species.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Acetylation
  • Animals
  • Anthracenes / pharmacology
  • Apoptosis Regulatory Proteins / metabolism
  • Apoptosis*
  • Bcl-2-Like Protein 11
  • Cell Differentiation
  • Cell Line
  • Cell Nucleus / metabolism
  • Down-Regulation
  • Embryonic Stem Cells / cytology*
  • Embryonic Stem Cells / metabolism
  • Forkhead Box Protein O1
  • Forkhead Transcription Factors / metabolism
  • JNK Mitogen-Activated Protein Kinases / antagonists & inhibitors
  • JNK Mitogen-Activated Protein Kinases / metabolism
  • Membrane Proteins / metabolism
  • Mercaptoethanol / pharmacology
  • Mice
  • PTEN Phosphohydrolase / metabolism
  • Phosphorylation
  • Protein Isoforms
  • Proto-Oncogene Proteins / metabolism
  • Reactive Oxygen Species / metabolism*
  • Sirtuin 1 / deficiency*
  • Sirtuin 1 / metabolism
  • Tumor Suppressor Protein p53 / metabolism
  • Tumor Suppressor Proteins / metabolism

Substances

  • Anthracenes
  • Apoptosis Regulatory Proteins
  • Bcl-2-Like Protein 11
  • Bcl2l11 protein, mouse
  • Forkhead Box Protein O1
  • Forkhead Transcription Factors
  • Foxo1 protein, mouse
  • Membrane Proteins
  • PUMA protein, mouse
  • Protein Isoforms
  • Proto-Oncogene Proteins
  • Reactive Oxygen Species
  • Tumor Suppressor Protein p53
  • Tumor Suppressor Proteins
  • pyrazolanthrone
  • Mercaptoethanol
  • JNK Mitogen-Activated Protein Kinases
  • PTEN Phosphohydrolase
  • Pten protein, mouse
  • Sirt1 protein, mouse
  • Sirtuin 1