Division of Clinical Pharmacology & Toxicology, University Hospital of Basel, Switzerland; Department of Biomedicine, University of Basel, Switzerland; Swiss Centre for Applied Human Toxicology (SCAHT), Basel, Switzerland.
Division of Clinical Pharmacology & Toxicology, University Hospital of Basel, Switzerland; Department of Biomedicine, University of Basel, Switzerland.
Free Radic Biol Med. 2020 May 20;152:216-226. doi: 10.1016/j.freeradbiomed.2020.03.009. Epub 2020 Mar 17.
The uricosuric benzbromarone is a mitochondrial toxicant associated with severe liver injury in patients treated with this drug. Since dysfunctional mitochondria can increase mitochondrial superoxide (O) production, we investigated the consequences of benzbromarone-induced mitochondrial oxidative stress on the hepatic antioxidative defense system. We exposed HepG2 cells (a human hepatocellular carcinoma cell line) to increasing concentrations of benzbromarone (1-100 μM) for different durations (2-24 h), and investigated markers of antioxidative defense and oxidative damage. At high concentrations (≥50 μM), benzbromarone caused accumulation of mitochondrial superoxide (O) and cellular reactive oxygen species (ROS). At concentrations >50 μM, benzbromarone increased the mitochondrial and cellular GSSG/GSH ratio and increased the oxidized portion of the mitochondrial thioredoxin 2. Benzbromarone stabilized the transcription factor NRF2 and caused its translocation into the nucleus. Consequently, the expression of the NRF2-regulated antioxidative proteins superoxide dismutase 1 (SOD1) and 2 (SOD2), glutathione peroxidase 1 (GPX1) and 4 (GPX4), as well as thioredoxin 1 (TRX1) and 2 (TRX2) increased. Finally, upregulation of NRF2 by siRNA-mediated knock-down of KEAP1 partially protected HepG2 cells from benzbromarone-induced membrane damage and ATP depletion. In conclusion, benzbromarone increased mitochondrial O accumulation and activates the NRF2 signaling pathway in HepG2 cells, thereby strengthening the cytosolic and mitochondrial antioxidative defense. Impaired antioxidative defense may represent a risk factor for benzbromarone-induced hepatotoxicity.
苯溴马隆是一种促进尿酸排泄的药物,与接受该药治疗的患者的严重肝损伤有关。由于功能失调的线粒体可以增加线粒体超氧化物(O)的产生,因此我们研究了苯溴马隆诱导的线粒体氧化应激对肝抗氧化防御系统的影响。我们将 HepG2 细胞(人肝癌细胞系)暴露于不同浓度(1-100 μM)的苯溴马隆(2-24 小时)中,并研究了抗氧化防御和氧化损伤的标志物。在高浓度(≥50 μM)时,苯溴马隆会导致线粒体超氧化物(O)和细胞内活性氧(ROS)的积累。在浓度>50 μM 时,苯溴马隆增加了线粒体和细胞的 GSSG/GSH 比值,并增加了线粒体硫氧还蛋白 2 的氧化部分。苯溴马隆稳定了转录因子 NRF2 并使其易位到细胞核中。因此,NRF2 调节的抗氧化蛋白超氧化物歧化酶 1(SOD1)和 2(SOD2)、谷胱甘肽过氧化物酶 1(GPX1)和 4(GPX4)以及硫氧还蛋白 1(TRX1)和 2(TRX2)的表达增加。最后,通过 siRNA 介导的 KEAP1 敲低上调 NRF2 可部分保护 HepG2 细胞免受苯溴马隆诱导的膜损伤和 ATP 耗竭。总之,苯溴马隆增加了 HepG2 细胞中线粒体 O 的积累并激活了 NRF2 信号通路,从而增强了细胞溶质和线粒体的抗氧化防御能力。抗氧化防御受损可能是苯溴马隆诱导肝毒性的一个危险因素。