Imai H, Sumi D, Sakamoto H, Hanamoto A, Arai M, Chiba N, Nakagawa Y
School of Pharmaceutical Sciences, Kitasato University, Tokyo, Japan.
Biochem Biophys Res Commun. 1996 May 15;222(2):432-8. doi: 10.1006/bbrc.1996.0762.
The role of phospholipid hydroperoxide glutathione peroxidase (PHGPx) in the cellular defense against oxidative stress was investigated in a novel cell model. We isolated stable transfectants of RBL-2H3 cells that overexpressed PHGPx. The activity of PHGPx in RBL2H3 cells that had been transfected with the 761bp cDNA for rat PHGPx (RPHGPx2) that we had cloned previously was 3.8 times higher than that in parent cells and in cells that had been mock-transfected with the vector without a cDNA insert. Cells that overexpressed PHGPx were three times more resistant than parent cells and mock-transfected cells to the cytotoxic effects of an radical initiator (AAPH) that induced the oxidative stress. This resistance to damage by AAPH of cells that overexpressed PHGPx was not observed after pretreatment with buthionine sulfoximine (BSO), an inhibitor of the synthesis of glutathione. Overexpression of PHGPx could suppress the peroxidation of membrane lipids and, in particular, the production of phosphatidylcholine hydroperoxide by AAPH in RBL2H3 cells. PHGPx was also able to prevent cell death in response to extracellular attack by a lipid peroxide. This is the first report to indicate directly that PHGPx can scavenge phosphatidylcholine hydroperoxide, which induces oxidative damage at the cellular level.
在一种新型细胞模型中研究了磷脂氢过氧化物谷胱甘肽过氧化物酶（PHGPx）在细胞抗氧化应激防御中的作用。我们分离出了过表达PHGPx的RBL-2H3细胞稳定转染子。用我们之前克隆的大鼠PHGPx（RPHGPx2）的761bp cDNA转染的RBL2H3细胞中，PHGPx的活性比亲代细胞和用无cDNA插入片段的载体进行空转染的细胞高3.8倍。过表达PHGPx的细胞对诱导氧化应激的自由基引发剂（AAPH）的细胞毒性作用的抗性比亲代细胞和空转染细胞高三倍。在用谷胱甘肽合成抑制剂丁硫氨酸亚砜胺（BSO）预处理后，未观察到过表达PHGPx的细胞对AAPH损伤的这种抗性。PHGPx的过表达可以抑制膜脂过氧化，特别是抑制RBL2H3细胞中AAPH诱导的磷脂酰胆碱氢过氧化物的产生。PHGPx还能够防止细胞因脂质过氧化物的细胞外攻击而死亡。这是第一份直接表明PHGPx可以清除在细胞水平诱导氧化损伤的磷脂酰胆碱氢过氧化物的报告。
