Department of Pharmacy and Pharmacology, University of Bath, Bath, UK.
San Raffaele Scientific Institute, Milan, Italy.
Free Radic Biol Med. 2014 Mar;68(100):87-100. doi: 10.1016/j.freeradbiomed.2013.12.006. Epub 2013 Dec 12.
To examine the role of intracellular labile iron pool (LIP), ferritin (Ft), and antioxidant defence in cellular resistance to oxidative stress on chronic adaptation, a new H2O2-resistant Jurkat T cell line "HJ16" was developed by gradual adaptation of parental "J16" cells to high concentrations of H2O2. Compared to J16 cells, HJ16 cells exhibited much higher resistance to H2O2-induced oxidative damage and necrotic cell death (up to 3mM) and had enhanced antioxidant defence in the form of significantly higher intracellular glutathione and mitochondrial ferritin (FtMt) levels as well as higher glutathione-peroxidase (GPx) activity. In contrast, the level of the Ft H-subunit (FtH) in the H2O2-adapted cell line was found to be 7-fold lower than in the parental J16 cell line. While H2O2 concentrations higher than 0.1mM fully depleted the glutathione content of J16 cells, in HJ16 cells the same treatments decreased the cellular glutathione content to only half of the original value. In HJ16 cells, H2O2 concentrations higher than 0.1mM increased the level of FtMt up to 4-fold of their control values but had no effect on the FtMt levels in J16 cells. Furthermore, while the basal cytosolic level of LIP was similar in both cell lines, H2O2 treatment substantially increased the cytosolic LIP levels in J16 but not in HJ16 cells. H2O2 treatment also substantially decreased the FtH levels in J16 cells (up to 70% of the control value). In contrast in HJ16 cells, FtH levels were not affected by H2O2 treatment. These results indicate that chronic adaptation of J16 cells to high concentrations of H2O2 has provoked a series of novel and specific cellular adaptive responses that contribute to higher resistance of HJ16 cells to oxidative damage and cell death. These include increased cellular antioxidant defence in the form of higher glutathione and FtMt levels, higher GPx activity, and lower FtH levels. Further adaptive responses include the significantly reduced cellular response to oxidant-mediated glutathione depletion, FtH modulation, and labile iron release and a significant increase in FtMt levels following H2O2 treatment.
为了研究细胞内可利用铁池（LIP）、铁蛋白（Ft）和抗氧化防御在慢性适应过程中细胞对氧化应激的抵抗作用中的作用，通过逐渐适应高浓度 H2O2，开发了一种新的 H2O2 抗性 Jurkat T 细胞系“HJ16”。与 J16 细胞相比，HJ16 细胞对 H2O2 诱导的氧化损伤和坏死性细胞死亡（高达 3mM）具有更高的抗性，并且具有增强的抗氧化防御，表现为细胞内谷胱甘肽和线粒体铁蛋白（FtMt）水平显著升高以及谷胱甘肽过氧化物酶（GPx）活性升高。相比之下，在 H2O2 适应的细胞系中，Ft 的 H 亚基（FtH）的水平发现比亲本 J16 细胞系低 7 倍。虽然 H2O2 浓度高于 0.1mM 可使 J16 细胞的谷胱甘肽含量完全耗尽，但在 HJ16 细胞中，相同的处理仅将细胞内谷胱甘肽含量降低至原始值的一半。在 HJ16 细胞中，H2O2 浓度高于 0.1mM 可使 FtMt 的水平增加到对照值的 4 倍，但对 J16 细胞的 FtMt 水平没有影响。此外，虽然两种细胞系的基础细胞质 LIP 水平相似，但 H2O2 处理可大大增加 J16 细胞质 LIP 水平，但不会增加 HJ16 细胞的 LIP 水平。H2O2 处理还可使 J16 细胞中的 FtH 水平降低（达对照值的 70％）。相反，在 HJ16 细胞中，H2O2 处理不会影响 FtH 水平。这些结果表明，J16 细胞对高浓度 H2O2 的慢性适应引发了一系列新的、特异的细胞适应性反应，有助于 HJ16 细胞对氧化损伤和细胞死亡的更高抗性。这些反应包括更高的谷胱甘肽和 FtMt 水平、更高的 GPx 活性和更低的 FtH 水平的形式的细胞抗氧化防御增强，以及氧化应激介导的谷胱甘肽耗竭、FtH 调节、细胞内不稳定铁释放以及 H2O2 处理后 FtMt 水平的显著增加的显著降低的细胞反应。
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