Metabolic control of resistance of human epithelial cells to H2O2 and NO stresses
Metabolic control of resistance of human epithelial cells to H2O2 and NO stresses
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DOI：
10.1042/bj20011856
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发表时间：
2002-06-01
影响因子：
4.1
通讯作者：
Laboisse, CL
中科院分区：
文献类型：
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作者：
Le Goffe, C;Vallette, G;Laboisse, CL
通过戊糖磷酸途径（PPP）的氧化分支的碳通量可以被视为通过NADPH的产生的抗氧化机制的集成器。因此，它可以用作细胞对氧化应激反应的控制点。用半乳糖替代葡萄糖使人上皮细胞系HGT-1对H2 O2应激敏感。在这里，我们证明，由于限制半乳糖流入PPP，H2 O2应激导致早期细胞起泡，随后细胞坏死，这些变化与NADPH/NADP（+）比值下降和GSH耗尽有关。通过添加2-脱氧葡萄糖（2dGlc）来防止H2 O2的细胞毒性。这种保护作用与2-脱氧葡萄糖6-磷酸流入PPP氧化分支的增加以及NADPH/NADP（+）下降的预防和细胞内GSH氧化还原稳态的维持有关。连接PPP到GSH再循环的酶途径的抑制剂废除了2dGlc保护。在无碳水化合物培养条件下，2dGlc剂量依赖性保护作用被2dGlc剂量依赖性流入PPP所抵消，导致细胞内氧化还原状态的维持。相比之下，在葡萄糖喂养的细胞中，PPP不是细胞对H2 O2应激的抗性的控制点，因为它们保持高NADPH/NADP（+）比率。2dGlc和Glc都通过维持GSH氧化还原状态来抑制NO对含半乳糖的Dulbecco改良Eagle培养基（Gal-DMEM）饲养的细胞的细胞毒性。2dGlc不能阻止NO处理的Gal-DMEM饲养细胞中ATP含量的下降，表明NO的细胞毒性基本上是由于GSH氧化还原稳态的破坏，而不是线粒体呼吸链ATP产生的改变。维持ATP含量在NO处理的葡萄糖喂养的细胞是由于他们的能力，以获得他们的能量从无氧糖酵解。总之，Gal-DMEM和2dGlc补充的Gal-DMEM提供了一个有用的系统，以破译和组织成一个层次的目标，在完整的屏障上皮细胞的水平上的几个应力。
The carbon flux through the oxidative branch of the pentose phosphate pathway (PPP) can be viewed as an integrator of the antioxidant mechanisms via the generation of NADPH. It could therefore be used as a control point of the cellular response to an oxidative stress. Replacement of glucose by galactose sensitized the human epithelial cell line HGT-1 to H2O2 stress. Here we demonstrate that, due to the restricted galactose flux into the PPP, the H2O2 stress led to early cellular blebbing followed by cell necrosis, these changes being associated with a fall in the NADPH/NADP(+) ratio and GSH depletion. H2O2 cytotoxicity was prevented by adding 2-deoxyglucose (2dGlc). This protection was associated with an increased flow of 2-deoxyglucose 6-phosphate into the oxidative branch of the PPP together with the prevention of the NADPH/NADP(+) fall and the maintenance of intracellular GSH redox homoeostasis. Inhibitors of enzyme pathways connecting the PPP to GSH recycling abolished the 2dGlc protection. In carbohydrate-free culture conditions, 2dGlc dose-dependent protective effect was paralleled by a dose-dependent influx of 2dGlc into the PPP leading to the maintenance of the intracellular redox status. By contrast, in Glc-fed cells, the PPP was not a control point of the cellular resistance to H2O2 stress as they maintained a high NADPH/NADP(+) ratio. Both 2dGlc and Glc inhibited, through the maintenance of GSH redox status, NO cytotoxicity on galactose-containing Dulbecco's modified Eagle's medium (Gal-DMEM)-fed cells. 2dGlc did not prevent the fall of ATP content in NO-treated Gal-DMEM-fed cells, indicating that NO cytotoxicity was essentially due to the disruption of GSH redox homoeostasis and not to the alteration of ATP production by the mitochondrial respiratory chain. The maintenance of ATP content in NO-treated glucose-fed cells was due to their ability to derive their energy from anaerobic glycolysis. In conclusion, Gal-DMEM and 2dGlc-supplemented Gal-DMEM provide a useful system to decipher and organize into a hierarchy the targets of several stresses at the level of intact barrier epithelial cells.