Nrf2 is activated by disruption of mitochondrial thiol homeostasis but not by enhanced mitochondrial superoxide production.
Nrf2 is activated by disruption of mitochondrial thiol homeostasis but not by enhanced mitochondrial superoxide production.
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DOI：
10.1074/jbc.ra120.016551
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发表时间：
2021-01
期刊：
影响因子：
--
通讯作者：
Murphy MP
中科院分区：
文献类型：
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作者：
Cvetko F;Caldwell ST;Higgins M;Suzuki T;Yamamoto M;Prag HA;Hartley RC;Dinkova-Kostova AT;Murphy MP
转录因子核因子红细胞2相关因子2（Nrf 2）调节参与抗氧化防御的基因的表达，以调节基本的细胞过程，如线粒体功能和GSH代谢。先前的报告提出，线粒体活性氧的产生和GSH池的破坏激活Nrf 2途径，表明Nrf 2感知线粒体氧化还原信号和/或氧化损伤，并向细胞核发出信号以做出适当的反应。然而，到目前为止，它还没有能够解开线粒体超氧化物/过氧化氢生产的重叠影响，作为一个氧化还原信号的变化，线粒体巯基稳态对Nrf 2。最近，我们开发了一种靶向线粒体的试剂，可以独立地诱导线粒体超氧化物和过氧化氢的产生mitoParaquat（MitoPQ）或选择性地破坏线粒体巯基稳态MitoChlorodinitrobenzoic acid（MitoCDNB）。使用这些试剂，在这里，我们已经确定了如何增强线粒体超氧化物和过氧化氢的生成或线粒体巯基稳态的破坏影响细胞中Nrf 2系统的激活，这是通过Nrf 2蛋白水平，核转位和其靶基因的表达来评估的。我们发现，线粒体GSH池的选择性破坏和MitoCDNB对其硫氧还蛋白系统的抑制导致Nrf 2活化，而使用MitoPQ单独增强线粒体超氧化物和过氧化氢的产生则没有。我们进一步表明，MitoCDNB激活Nrf 2需要Kelch样ECH相关蛋白1（Keap 1）的半胱氨酸传感器。这些发现提供了关于线粒体氧化还原稳态的破坏如何在细胞质中被感知并向细胞核发出信号的重要信息。
The transcription factor nuclear factor erythroid 2–related factor 2 (Nrf2) regulates the expression of genes involved in antioxidant defenses to modulate fundamental cellular processes such as mitochondrial function and GSH metabolism. Previous reports proposed that mitochondrial reactive oxygen species production and disruption of the GSH pool activate the Nrf2 pathway, suggesting that Nrf2 senses mitochondrial redox signals and/or oxidative damage and signals to the nucleus to respond appropriately. However, until now, it has not been possible to disentangle the overlapping effects of mitochondrial superoxide/hydrogen peroxide production as a redox signal from changes to mitochondrial thiol homeostasis on Nrf2. Recently, we developed mitochondria-targeted reagents that can independently induce mitochondrial superoxide and hydrogen peroxide production mitoParaquat (MitoPQ) or selectively disrupt mitochondrial thiol homeostasis MitoChlorodinitrobenzoic acid (MitoCDNB). Using these reagents, here we have determined how enhanced generation of mitochondrial superoxide and hydrogen peroxide or disruption of mitochondrial thiol homeostasis affects activation of the Nrf2 system in cells, which was assessed by the Nrf2 protein level, nuclear translocation, and expression of its target genes. We found that selective disruption of the mitochondrial GSH pool and inhibition of its thioredoxin system by MitoCDNB led to Nrf2 activation, whereas using MitoPQ to enhance the production of mitochondrial superoxide and hydrogen peroxide alone did not. We further showed that Nrf2 activation by MitoCDNB requires cysteine sensors of Kelch-like ECH-associated protein 1 (Keap1). These findings provide important information on how disruption to mitochondrial redox homeostasis is sensed in the cytoplasm and signaled to the nucleus.