Ser9 phosphorylation of mitochondrial GSK-3β is a primary mechanism of cardiomyocyte protection by erythropoietin against oxidant-induced apoptosis
Ser9 phosphorylation of mitochondrial GSK-3β is a primary mechanism of cardiomyocyte protection by erythropoietin against oxidant-induced apoptosis
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DOI：
10.1152/ajpheart.00092.2008
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发表时间：
2008-11-01
影响因子：
4.8
通讯作者：
Shimamoto, Kazuaki
中科院分区：
文献类型：
--
作者：
Ohori, Katsuhiko;Miura, Tetsuji;Shimamoto, Kazuaki
[10]杨文，李文，李文.线粒体GSK-3 β的Ser 9磷酸化是促红细胞生成素保护心肌细胞对抗氧化剂诱导凋亡的主要机制。美国生理学杂志心脏循环生理学295：H2079-H2086，2008年。首次发表于2008年9月19日; doi：10.1152/ajpheart.00092.2008。本研究的目的是确定GSK-3 β在促红细胞生成素（EPO）对氧化应激诱导的细胞凋亡的心肌细胞保护中的作用。用EPO（10单位/ml）处理诱导Akt的Ser 473磷酸化和GSK-3 β的Ser 9磷酸化，并显著降低暴露于H2 O2后凋亡H9 c2心肌细胞的比例，从38.3 +/- 2.7%降至26.0 +/-2.9%。这种保护作用在用组成型活性GSK-3 β（S9 A）转染的细胞中未检测到，后者缺乏抑制磷酸化的Ser 9。EPO的抗凋亡作用完全通过使用小干扰RNA敲低GSK-3 β来模拟，部分通过转染激酶缺陷型GSK-3 β（K85 R）来模拟。通过增强的绿色荧光蛋白标记的GSK-3 β或免疫细胞化学评估的细胞内GSK-3 β与线粒体的共定位水平没有被EPO处理改变。然而，EPO以磷脂酰肌醇3-激酶依赖性方式使与线粒体共定位的Ser 9-磷酸GSK-3 β水平增加50%。EPO预处理和GSK-3 β敲低可抑制暴露于H2 O2后Bcl 2相关X蛋白（BAX）的线粒体易位。这些结果表明，通过线粒体中Akt介导的Ser 9磷酸化抑制GSK-3 β活性，可能通过抑制BAX进入线粒体，使心肌细胞耐受氧化剂诱导的细胞凋亡。
Ohori K, Miura T, Tanno M, Miki T, Sato T, Ishikawa S, Horio Y, Shimamoto K. Ser9 phosphorylation of mitochondrial GSK-3 beta is a primary mechanism of cardiomyocyte protection by erythropoietin against oxidant-induced apoptosis. Am J Physiol Heart Circ Physiol 295: H2079-H2086, 2008. First published September 19, 2008; doi: 10.1152/ajpheart.00092.2008.-The aim of this study was to determine the role of GSK-3 beta in cardiomyocyte protection afforded by erythropoietin (EPO) against oxidant stress-induced apoptosis. Treatment with EPO (10 units/ml) induced Ser473 phosphorylation of Akt and Ser9 phosphorylation of GSK-3 beta and significantly reduced the proportion of apoptotic H9c2 cardiomyocytes after exposure to H2O2 from 38.3 +/- 2.7% to 26.0 +/- 2.9%. This protection was not detected in cells transfected with constitutively active GSK-3 beta (S9A), which lacks Ser9 for inhibitory phosphorylation. The antiapoptotic effect of EPO was mimicked completely by GSK-3 beta knockdown using small interfering RNA and partly by the transfection with kinase-deficient GSK-3 beta (K85R). The level of colocalization of intracellular GSK-3 beta with mitochondria assessed by enhanced green fluorescent proteintagged GSK-3 beta or immunocytochemistry was not altered by EPO treatment. However, EPO increased the level of Ser9-phosphoGSK-3 beta colocalized with mitochondria by 50% in a phosphatidylinositol 3-kinase-dependent manner. Mitochondrial translocation of Bcl2-associated X protein (BAX) after exposure to H2O2 was inhibited by EPO pretreatment and by GSK-3 beta knockdown. These results suggest that the suppression of GSK-3 beta activity by Akt-mediated Ser9 phosphorylation in the mitochondria affords cardiomyocytes tolerance against oxidant-induced apoptosis, possibly by inhibiting the access of BAX to the mitochondria.