Heat shock protein 70 regulates cellular redox status by modulating glutathione-related enzyme activities
Heat shock protein 70 regulates cellular redox status by modulating glutathione-related enzyme activities
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DOI：
10.1379/csc-265.1
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发表时间：
2007-09-01
影响因子：
3.8
通讯作者：
Shi, Honglian
中科院分区：
文献类型：
--
作者：
Guo, Shuhong;Wharton, Walker;Shi, Honglian
热休克蛋白（Hsp）70已被报道可以保护各种细胞和组织免受。缺血性损伤然而，保护的分子机制还不完全清楚。缺血诱导细胞氧化还原状态的显著改变，其在细胞存活/死亡途径中起关键作用。我们研究了Hsp 70过表达对缺氧和缺血条件下Madin-Darby犬肾（MDCK）细胞氧化还原状态的影响，采用3种不同的方法：荧光探针法测量活性氧（ROS），羟胺自旋探针法评价氧化还原环境，谷胱甘肽/谷胱甘肽二硫化物（GSH/GSSG）比值法评价氧化还原状态。从这些方法的结果表明，在Hsp 70细胞的氧化还原状态比在缺氧或氧和葡萄糖剥夺（OGD）条件下的对照细胞。为了确定介导Hsp 70细胞氧化还原状态改变的机制，我们测量了谷胱甘肽过氧化物酶（GPx）和谷胱甘肽还原酶（GR），两种谷胱甘肽相关的抗氧化酶的活性。我们发现，OGD暴露增加GPx和GR活动47%和55%，从他们的基础水平（无应力）在Hsp 70细胞，相比之下，只有18%和0%的增加，分别在控制细胞。这些数据，第一次表明，热休克蛋白70调节GPx和GR的活动，调节细胞的氧化还原状态，在响应缺血应激，这可能是重要的热休克蛋白70的细胞保护作用。
Heat shock protein (Hsp) 70 has been reported to protect various cells and tissues from. ischemic damage. However, the molecular mechanisms of the protection are incompletely understood. Ischemia induces significant alterations in cellular redox status that plays a critical role in cell survival/death pathways. We investigated the effects of Hsp70 overexpression on cellular redox status in Madin-Darby canine kidney (MDCK) cells under both hypoxic and ischemic conditions with 3 different approaches: reactive oxygen species (ROS) measurement by a fluorescence probe, redox environment evaluation by a hydroxylamine spin probe, and redox status assessment by the glutathione/glutathione disulfide (GSH/GSSG) ratio. Results from each of these approaches showed that the redox status in Hsp70 cells was more reducing than that in control cells under either hypoxic or oxygen and glucose deprivation (OGD) conditions. In order to determine the mechanisms that mediated the alterations in redox state in Hsp70 cells, we measured the activities of glutathione peroxidase (GPx) and glutathione reductase (GR), two GSH-related antioxidant enzymes. We found that OGD exposure increased GPx and GR activities 47% and 55% from their basal levels (no stress) in Hsp70 cells, compared to only 18% and 0% increase in control cells, respectively. These data, for the first time, indicate that Hsp70 modulates the activities of GPx and GR that regulate cellular redox status in response to ischemic stress, which may be important in Hsp70's cytoprotective effects.