PDF(Pubmed)
Abstract：
Nonsteroidal anti-inflammatory drug (NSAID) use is associated with adverse consequences, including hepatic injury. The detrimental hepatotoxicity of diclofenac, a widely used NSAID, is primarily connected to oxidative damage in mitochondria, which are the primary source of reactive oxygen species (ROS). The primary ROS responsible for inducing diclofenac-related hepatocellular toxicity and the principal antioxidant that mitigates these ROS remain unknown. Peroxiredoxin III (PrxIII) is the most abundant and potent H2O2-eliminating enzyme in the mitochondria of mammalian cells. Here, we investigated the role of mitochondrial H2O2 and the protective function of PrxIII in diclofenac-induced mitochondrial dysfunction and apoptosis in hepatocytes. Mitochondrial H2O2 levels were differentiated from other types of ROS using a fluorescent H2O2 indicator. Upon diclofenac treatment, PrxIII-knockdown HepG2 human hepatoma cells showed higher levels of mitochondrial H2O2 than PrxIII-expressing controls. PrxIII-depleted cells exhibited higher mitochondrial dysfunction as measured by a lower oxygen consumption rate, loss of mitochondrial membrane potential, cardiolipin oxidation, and caspase activation, and were more sensitive to apoptosis. Ectopic expression of mitochondrially targeted catalase in PrxIII-knockdown HepG2 cells or in primary hepatocytes derived from PrxIII-knockout mice suppressed the diclofenac-induced accumulation of mitochondrial H2O2 and decreased apoptosis. Thus, we demonstrated that mitochondrial H2O2 is a key mediator of diclofenac-induced hepatocellular damage driven by mitochondrial dysfunction and apoptosis. We showed that PrxIII loss results in the critical accumulation of mitochondrial H2O2 and increases the harmful effects of diclofenac. PrxIII or other antioxidants targeting mitochondrial H2O2 could be explored as potential therapeutic agents to protect against the hepatotoxicity associated with NSAID use.
摘要：
非甾体抗炎药（NSAID）的使用与不良后果有关，包括肝损伤。双氯芬酸的有害肝毒性，一种广泛使用的非甾体抗炎药，主要与线粒体的氧化损伤有关，是活性氧（ROS）的主要来源。负责诱导双氯芬酸相关肝细胞毒性的主要ROS和减轻这些ROS的主要抗氧化剂仍然未知。过氧化物酶III（PrxIII）是哺乳动物细胞线粒体中最丰富和最有效的H2O2消除酶。这里,我们研究了线粒体H2O2和PrxIII在双氯芬酸诱导的肝细胞线粒体功能障碍和凋亡中的作用。使用荧光H2O2指示剂将线粒体H2O2水平与其他类型的ROS区分开。在双氯芬酸治疗后,与表达PrxIII的对照相比，PrxIII敲低的HepG2人肝癌细胞显示出更高水平的线粒体H2O2。通过较低的耗氧率测量，PrxIII耗竭细胞表现出更高的线粒体功能障碍，线粒体膜电位的丧失，心磷脂氧化，和半胱天冬酶激活，对细胞凋亡更敏感。线粒体靶向过氧化氢酶在PrxIII敲低的HepG2细胞或源自PrxIII敲除小鼠的原代肝细胞中的异位表达抑制了双氯芬酸诱导的线粒体H2O2积累并减少了细胞凋亡。因此，我们证明线粒体H2O2是双氯芬酸诱导的由线粒体功能障碍和细胞凋亡驱动的肝细胞损伤的关键介质。我们表明，PrxIII损失导致线粒体H2O2的临界积累，并增加了双氯芬酸的有害作用。PrxIII或其他靶向线粒体H2O2的抗氧化剂可以作为潜在的治疗剂来探索，以防止与NSAID使用相关的肝毒性。
