H2O2 accelerates cellular senescence by accumulation of acetylated p53 via decrease in the function of SIRT1 by NAD+ depletion
H2O2 accelerates cellular senescence by accumulation of acetylated p53 via decrease in the function of SIRT1 by NAD+ depletion
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DOI：
10.1159/000104152
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发表时间：
2007-01-01
影响因子：
--
通讯作者：
Oikawa, Shinji
中科院分区：
文献类型：
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作者：
Furukawa, Ayako;Tada-Oikawa, Saeko;Oikawa, Shinji
据报道，促进细胞衰老的p53乙酰化可以由NAD（+）依赖性脱乙酰酶SIRT 1调节，SIRT 1是酵母Sir 2的人类同源物，是一种调节寿命的蛋白质。为了阐明SIRT 1在氧化应激诱导的细胞衰老中的作用，我们用H2 O2处理正常人二倍体成纤维细胞TIG-3细胞，并检测DNA切割、细胞内NAD（+）的消耗、p21、SIRT 1和乙酰化p53的表达、细胞周期停滞和衰老相关的β-半乳糖苷酶（SA-β-gal）活性。在用H2 O2处理的TIG-3细胞中立即观察到DNA切割，尽管没有观察到细胞死亡。H_2O_2处理后的TIG-3细胞NAD（+）水平明显降低。用聚（ADP-核糖）聚合酶（PARP）抑制剂预孵育可保持细胞内NAD（+）水平。H2 O2处理后4小时，TIG-3细胞中乙酰化p53的量增加，而SIRT 1蛋白表达几乎没有下降。p21表达水平在12 h时增加，并持续增加至24 h。此外，暴露于H2 O2的TIG-3细胞在24小时诱导细胞周期停滞，并在48小时增加SA-β-gal活性。该途径可能在氧化应激加速细胞衰老中起重要作用。
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 H2O2 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 H2O2, though no cell death was observed. NAD(+) levels in TIG-3 cells treated with H2O2 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 H2O2 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 H2O2 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.