Among reactive oxygen species (ROS), H₂O₂ alone acts as a signaling molecule that promotes diverse phenotypes depending on the intracellular concentration. Mitochondria have been suggested as both sources and sinks of cellular H₂O₂, and mitochondrial dysfunction has been implicated in diseases such as cancer. A genetically encoded H₂O₂ generator, d-amino acid oxidase (DAAO), was targeted to the mitochondria of human cells, and its utility in investigating cellular response to a range of H₂O₂ doses over time was assessed. Organelle-specific peroxiredoxin dimerization and protein S-glutathionylation were measured as indicators of increased H₂O₂ flux due to the activity of DAAO. Cell death was observed in a concentration- and time-dependent manner, and protein oxidation shifted in localization as the dose increased. This work presents the first systematic study of H₂O₂-specific perturbation of mitochondria in human cells, and it reveals a marked sensitivity of this organelle to increases in H₂O₂ in comparison with prior studies that targeted the cytosol.

中文翻译：

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线粒体H ₂ O _2的生成使用可调的化学生成工具来扰乱人体细胞中的氧化还原稳态并诱导细胞死亡

在活性氧（ROS）中，单独的H ₂ O ₂充当信号分子，根据细胞内浓度促进不同的表型。线粒体被认为是细胞H ₂ O _2的来源和汇聚体，线粒体功能障碍与癌症等疾病有关。遗传编码的H ₂ O ₂产生剂d-氨基酸氧化酶（DAAO）靶向人类细胞的线粒体，并评估了其在研究细胞对H ₂ O ₂剂量随时间变化的反应中的效用。细胞器特有的过氧化物酶二聚体和蛋白S测量了谷胱甘肽酰化作为由于DAAO的活性而增加的H ₂ O ₂通量的指标。以浓度和时间依赖性的方式观察到细胞死亡，并且随着剂量的增加，蛋白质的氧化在局部发生转移。这项工作提出了人类细胞中线粒体对H ₂ O ₂特异性扰动的第一个系统研究，并且与针对细胞溶质的先前研究相比，它揭示了该细胞器对H ₂ O ₂升高的显着敏感性。