SIRT1 Deficiency Downregulates PTEN/JNK/FOXO1 Pathway to Block Reactive Oxygen Species-Induced Apoptosis in Mouse Embryonic Stem Cells
SIRT1 Deficiency Downregulates PTEN/JNK/FOXO1 Pathway to Block Reactive Oxygen Species-Induced Apoptosis in Mouse Embryonic Stem Cells
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DOI：
10.1089/scd.2010.0465
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发表时间：
2011-07-01
影响因子：
4
通讯作者：
Broxmeyer, Hal E.
中科院分区：
文献类型：
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作者：
Chae, Hee-Don;Broxmeyer, Hal E.
沉默交配型信息调节 2 同源物 1 (SIRT1) 在活性氧引发的小鼠胚胎干 (mES) 细胞凋亡中发挥着关键作用。在这里，我们研究了 PTEN/Akt/JNK 通路在 SIRT1 介导的 mES 细胞凋亡通路中的可能作用。 Akt 通过去除 SIRT1(-/-) mES 细胞中的抗氧化剂 2-巯基乙醇而被激活。由于 PTEN 是 Akt 的负调节因子，并且其活性可以通过乙酰化来调节，因此我们研究了 SIRT1 去乙酰化 PTEN 是否会下调 Akt，从而在无抗氧化剂的培养条件下触发细胞凋亡。在 SIRT1(-/-) mES 细胞中，PTEN 被过度乙酰化并被排除在细胞核之外，这与增强的 Akt 活性一致。 SIRT1 缺陷增强了 FOXO1 的乙酰化/磷酸化水平，随后抑制了 FOXO1 的核定位。细胞乙酰化水平是通过 DNA 损伤剂而不是通过去除抗氧化剂来增强的。 c-Jun NH2 末端激酶 (JNK) 通过以 SIRT1 依赖性方式去除抗氧化剂而被激活。尽管 p53 乙酰化在 SIRT1(-/-) mES 细胞中更强，但无论 SIRT1 如何，DNA 损伤性应激都会激活磷酸化并增强 p53 的细胞水平，而去除抗氧化剂仅会在 SIRT1 作用下轻微激活 p53。 Bim 和 Puma 的表达水平在无抗氧化剂的培养条件下以 SIRT1 依赖性方式增加，并且用 JNK 抑制剂处理可阻断 Bim 表达的诱导。无论 SIRT1 如何，DNA 损伤剂都会激活 caspase3。我们的数据支持 SIRT1 在准备 PTEN/JNK/FOXO1 途径响应细胞活性氧中发挥重要作用。
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.