Insulin-like growth factor 1 specifically up-regulates expression of modifier subunit of glutamate-cysteine ligase and enhances glutathione synthesis in SH-SY5Y cells.
Insulin-like growth factor 1 specifically up-regulates expression of modifier subunit of glutamate-cysteine ligase and enhances glutathione synthesis in SH-SY5Y cells.
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DOI：
10.1016/j.ejphar.2015.12.013
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发表时间：
2016-01
影响因子：
5
通讯作者：
Shuhei Takahashi;A. Hisatsune;Y. Kurauchi;T. Seki;H. Katsuki
中科院分区：
文献类型：
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作者：
Shuhei Takahashi;A. Hisatsune;Y. Kurauchi;T. Seki;H. Katsuki
谷胱甘肽是所有哺乳动物氧化平衡的关键调节剂，特别是在中枢神经系统中。谷胱甘肽合成的第一步由谷氨酸-半胱氨酸连接酶（GCL）催化，GCL由催化亚基和修饰亚基（分别为GCLC和GCLM）组成。在非神经细胞和组织中，胰岛素和胰岛素样生长因子1 （IGF-1）可刺激GCLC基因的转录。在这里，我们发现用胰岛素或IGF-1治疗人神经母细胞瘤SH-SY5Y细胞增加GCLM mRNA水平，但不增加GCLC mRNA水平，并以浓度和时间依赖的方式。相比之下，胰岛素没有增加大鼠C6胶质瘤细胞中GCL的表达。我们还证实IGF-1增加了SH-SY5Y细胞中GCLM蛋白水平和细胞谷胱甘肽含量。此外，IGF-1增加SH-SY5Y细胞核部分的核因子红系2相关因子2 （Nrf2）蛋白。sirna介导的Nrf2蛋白表达下调消除了igf -1诱导的GCLM mRNA表达上调。最后，igf -1诱导的核Nrf2蛋白和GCLM mRNA表达升高被磷酸肌苷3激酶抑制剂LY294002消除。这些结果表明，胰岛素和IGF-1能够通过特异性上调GCLM的表达来促进神经细胞中谷胱甘肽的生物合成。
Glutathione is a key regulator of oxidative balance in all mammals, especially in the central nervous system. The first step of glutathione synthesis is catalyzed by glutamate-cysteine ligase (GCL), which is composed of catalytic and modifier subunits (GCLC and GCLM, respectively). In non-neural cells and tissues, insulin and insulin-like growth factor 1 (IGF-1) have been found to stimulate transcription of GCLC gene. Here we found that treatment of human neuroblastoma SH-SY5Y cells with insulin or IGF-1 increased mRNA level of GCLM, but not of GCLC, in a concentration- and time-dependent manner. In contrast, insulin did not increase GCL expression in rat C6 glioma cells. We also confirmed that IGF-1 increased protein level of GCLM and cellular glutathione content in SH-SY5Y cells. In addition, IGF-1 increased nuclear factor erythroid 2-related factor 2 (Nrf2) protein in the nuclear fraction of SH-SY5Y cells. siRNA-mediated knockdown of Nrf2 protein expression abrogated IGF-1-induced up-regulation of GCLM mRNA expression. Finally, IGF-1-induced increase in nuclear Nrf2 protein and GCLM mRNA expression was abolished by LY294002, a phosphoinositide 3-kinase inhibitor. These results indicate that insulin and IGF-1 have the ability to enhance glutathione biosynthesis in neuronal cells via specific up-regulation of GCLM expression.