Jian Wenying, Lee Seon Hwa, Mesaros Clementina, Oe Tomoyuki, Elipe Maria V Silva, Blair Ian A
Centers for Cancer Pharmacology and Excellence in Environmental Toxicology, University of Pennsylvania School of Medicine, 854 BRB II/III, 421 Curie Boulevard, Philadelphia Pennsylvania 19104-6160, USA.
Chem Res Toxicol. 2007 Jul;20(7):1008-18. doi: 10.1021/tx700001t. Epub 2007 Jun 6.
Cellular oxidative stress causes increased lipid peroxidation with the concomitant formation of DNA and protein reactive bifunctional electrophiles. Glutathione (GSH) detoxifies these bifunctional electrophiles by forming GSH adducts. Several years ago we discovered 4-oxo-2(E)-nonenal (ONE) as a major bifunctional electrophile derived from lipid hydroperoxides. We have now made the unexpected discovery that glutathione-S-transferase (GST)-mediated GSH addition to ONE occurs primarily to C-1 of the alpha,beta-unsaturated ketone rather than to C-3 of the alpha,beta-unsaturated aldehyde. The resulting intermediate rapidly undergoes two intramolecular cyclizations followed by two separate dehydration reactions to provide an unusual thiadiazabicyclo-ONE-GSH adduct (TOG). Quantification of intracellular TOG was performed using stable isotope dilution liquid chromatography-multiple reaction monitoring/mass spectrometry after the addition of ONE to cells or as an endogenously derived adduct during peroxide-induced oxidative stress. TOG represents the first member of a new class of thiadiazabicyclo GSH adducts that are formed through GST-mediated addition of GSH to reactive intermediates containing the ONE motif during intracellular oxidative stress. ONE formation can potentially result from free radical pathways as well as cyclooxygenase- and lipoxygenase-mediated pathways. Its aldo-keto reductase-mediated reduction product, 4-oxo-2(E)-nonenol (ONO), was also formed and converted to GSH adducts similar to those formed by 4-hydroxy-2(E)-nonenal (HNE). ONO is isomeric with HNE; therefore, protein and peptide adducts ascribed to arise solely from reactions with endogenous HNE will need to be re-appraised.
细胞氧化应激会导致脂质过氧化增加，并伴随形成DNA和蛋白质反应性双功能亲电试剂。谷胱甘肽（GSH）通过形成GSH加合物来解毒这些双功能亲电试剂。几年前，我们发现4-氧代-2（E）-壬烯醛（ONE）是一种主要的源自脂质氢过氧化物的双功能亲电试剂。我们现在有了一个意外的发现，即谷胱甘肽-S-转移酶（GST）介导的GSH与ONE的加成主要发生在α，β-不饱和酮的C-1位，而不是α，β-不饱和醛的C-3位。生成的中间体迅速经历两次分子内环化，随后进行两次单独的脱水反应，以提供一种不寻常的噻二氮杂双环-ONE-GSH加合物（TOG）。在向细胞中添加ONE后，或在过氧化物诱导的氧化应激期间作为内源性衍生的加合物，使用稳定同位素稀释液相色谱-多反应监测/质谱法对细胞内TOG进行定量。TOG代表了一类新的噻二氮杂双环GSH加合物中的第一个成员，这类加合物是在细胞内氧化应激期间通过GST介导的GSH与含有ONE基序的反应性中间体加成而形成的。ONE的形成可能源于自由基途径以及环氧化酶和脂氧合酶介导的途径。其醛酮还原酶介导的还原产物4-氧代-2（E）-壬烯醇（ONO）也会形成，并转化为与4-羟基-2（E）-壬烯醛（HNE）形成的GSH加合物类似的加合物。ONO与HNE是同分异构体；因此，归因于仅与内源性HNE反应产生的蛋白质和肽加合物需要重新评估。
