title: H2O2 accelerates cellular senescence by accumulation of acetylated p53 via decrease in the function of SIRT1 by NAD+ depletion.
abstract: It has been reported that p53 acetylation, which promotes cellular senescence, can be regulated by the NAD(+)-dependent deacetylase SIRT1, the human homolog of yeast Sir2, a protein that modulates lifespan. To clarify the role of SIRT1 in cellular senescence induced by oxidative stress, we treated normal human diploid fibroblast TIG-3 cells with H(2)O(2) and examined DNA cleavage, depletion of intracellular NAD(+), expression of p21, SIRT1, and acetylated p53, cell cycle arrest, and senescence-associated beta-galactosidase (SA-beta-gal) activity. DNA cleavage was observed immediately in TIG-3 cells treated with H(2)O(2), though no cell death was observed. NAD(+) levels in TIG-3 cells treated with H(2)O(2) were also decreased significantly. Pre-incubation with the poly (ADP-ribose) polymerase (PARP) inhibitor resulted in preservation of intracellular NAD(+) levels. The amount of acetylated p53 was increased in TIG-3 cells at 4h after H(2)O(2) treatment, while there was little to no decrease in SIRT1 protein expression. The expression level of p21 was increased at 12h and continued to increase for up to 24h. Additionally, exposure of TIG-3 cells to H(2)O(2) induced cell cycle arrest at 24h and increased SA-beta-gal activity at 48h. This pathway likely plays an important role in the acceleration of cellular senescence by oxidative stress.
authors.affiliation: Department of Environmental and Molecular Medicine, Mie University Graduate School of Medicine, Mie, Japan.
authors.forename: Ayako
authors.initials: A
authors.lastname: Furukawa
authors.forename: Saeko
authors.initials: S
authors.lastname: Tada-Oikawa
authors.forename: Shosuke
authors.initials: S
authors.lastname: Kawanishi
authors.forename: Shinji
authors.initials: S
authors.lastname: Oikawa
mesh_terms: D000107:Acetylation; D001483:Base Sequence; D002453:Cell Cycle / Q000187:drug effects; D002460:Cell Line; D016922:Cellular Senescence / Q000187:drug effects* / Q000502:physiology*; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D004249:DNA Damage; D006801:Humans; D006861:Hydrogen Peroxide / Q000633:toxicity*; D009243:NAD / Q000378:metabolism; D018384:Oxidative Stress; D034741:RNA, Small Interfering / Q000235:genetics; D056564:Sirtuin 1; D037761:Sirtuins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000737:chemistry / Q000378:metabolism*; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D034741:RNA, Small Interfering; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D009243:NAD; D006861:Hydrogen Peroxide; D001616:beta-Galactosidase; C447939:SIRT1 protein, human; D056564:Sirtuin 1; D037761:Sirtuins