Department of Molecular Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
Cell Death Dis. 2012 Nov 15;3(11):e422. doi: 10.1038/cddis.2012.156.
Mitochondrial respiratory dysfunction has intimate relationship with redox regulation. The key mechanism about how the mitochondrial respiration-defective cells survive oxidative stress is still elusive. Here, we report that transcription factor zinc-finger protein 143 (ZNF143) expression and glutathione peroxidase (GPX) activity are markedly increased in the mitochondrial respiratory-defective cells induced by dominant-negative DNA polymerase γ (POLGdn). In this work, investigation of the cellular antioxidant glutathione (GSH) and enzyme GPX activity in the mitochondrial dysfunction revealed the presence of an increased synthesis of GSH through the activation of GCLC (glutamate-cysteine ligase catalytic subunit) and GCLM (glutamate-cysteine ligase regulatory subunit) gene expression, and also a positive upregulation of glutathione peroxidase 1 (GPX1) activity by the transcription factor ZNF143. Significant increase in gene expression of SepSecS, the key enzyme responsible for selenocysteine transfer RNA (tRNA) synthesis, further confirmed the activation of the selenocysteine synthesis pathway. By using both GPX1 and ZNF143 knockdown, we provided insight into the involvement of ZNF143 in promoting GPX1 activity and protecting cells from oxidative damage and cisplatin treatment in the mitochondrial dysfunction. Furthermore, we reported the possible regulation of mitochondrial transcription factor A (TFAM) in the mitochondrial dysfunction. Our findings delineate an important antioxidant survival pathway that allows the mitochondrial-defective cells to survive oxidative stress and cisplatin treatment.
线粒体呼吸功能障碍与氧化还原调节密切相关。线粒体呼吸缺陷细胞如何在氧化应激下存活的关键机制仍不清楚。在这里,我们报告转录因子锌指蛋白 143(ZNF143)的表达和谷胱甘肽过氧化物酶(GPX)活性在由显性负突变 DNA 聚合酶γ(POLGdn)诱导的线粒体呼吸缺陷细胞中显著增加。在这项工作中,对线粒体功能障碍细胞内抗氧化谷胱甘肽(GSH)和酶 GPX 活性的研究表明,通过激活 GCLC(谷氨酸-半胱氨酸连接酶催化亚基)和 GCLM(谷氨酸-半胱氨酸连接酶调节亚基)基因表达,GSH 的合成增加,并且谷胱甘肽过氧化物酶 1(GPX1)的活性也通过转录因子 ZNF143 被正向上调。参与硒代半胱氨酸 tRNA(tRNA)合成的关键酶 SepSecS 的基因表达显著增加,进一步证实了硒代半胱氨酸合成途径的激活。通过使用 GPX1 和 ZNF143 的敲低,我们深入了解了 ZNF143 在促进 GPX1 活性和保护线粒体功能障碍细胞免受氧化损伤和顺铂治疗中的作用。此外,我们报道了线粒体转录因子 A(TFAM)在线粒体功能障碍中的可能调节作用。我们的发现描绘了一条重要的抗氧化生存途径,使线粒体缺陷细胞能够在氧化应激和顺铂治疗下存活。