Matsunaga Toshiyuki, Kamase Kyoko, Takasawa Hiroaki, Yamaji Yukiko, Endo Satoshi, El-Kabbani Ossama, Ikari Akira
Laboratory of Biochemistry, Gifu Pharmaceutical University, Gifu, 501-1196, Japan.
Laboratory of Biochemistry, Gifu Pharmaceutical University, Gifu, 501-1196, Japan.
Chem Biol Interact. 2018 Jan 5;279:10-20. doi: 10.1016/j.cbi.2017.10.028. Epub 2017 Nov 10.
9,10-Phenanthrenequinone (PQ), a major quinone component in diesel exhaust particles, is considered to provoke damage of respiratory and vascular cells through highly producing reactive oxygen species (ROS), but little is known about its pathophysiological role in neuronal cell damage. In this study, we found that incubation with 1,2-naphthoquinone, 1,4-naphthoquinone and PQ, major quinone components in diesel exhausts, provokes apoptosis of human neuroblastoma cell lines. SK-N-SH cell treatment with a lethal concentration of PQ facilitated ROS production within 6 h. The treatment also promoted formation of 8-hydroxy-deoxyguanosine, p53 activation, elevation of Bax/Bcl-2 ratio, lowering of mitochondrial membrane potential, and resultant activation of caspase-9 and caspase-3, inferring that ROS production, DNA damage and mitochondrial dysfunction are crucial processes of the PQ-triggered SK-N-SH cell apoptosis. The PQ treatment of SK-N-SH cells elevated the level of 4-hydroxynonenal (HNE), a cytotoxic reactive aldehyde generated from lipid peroxidation. The treatment with PQ and HNE also decreased cellular levels of total and reduced glutathiones, and the damage elicited by HNE was ameliorated and deteriorated by pretreating with cell-permeable glutathione analog and the depletor, respectively. Moreover, the treatment with PQ and HNE decreased the proteasomal proteolytic activities, suggesting a contribution of decrease in the antioxidant abilities to the ROS-mediated neuroblastoma cell apoptosis. Our comparative analyses of 17 cells showed a positive correlation between the PQ reductase and NAD(P)H:quinone oxidoreductase 1 (NQO1) activities. In addition, overexpression and knockdown of NQO1 augmented and lowered, respectively, the ROS production through PQ redox-cycling and the quinone toxicity. Furthermore, the treatment with PQ and HNE up-regulated the NQO1 expression. Taken together, PQ exposure produces large amounts of ROS in neuroblastoma cells via NQO1 up-regulation and resultant acceleration of its redox-cycling, followed by activation of the ROS-dependent apoptotic mechanism.
9,10-菲醌（PQ）是柴油废气颗粒中的一种主要醌类成分，被认为可通过大量产生活性氧（ROS）引发呼吸道和血管细胞损伤，但关于其在神经元细胞损伤中的病理生理作用知之甚少。在本研究中，我们发现用柴油废气中的主要醌类成分1,2-萘醌、1,4-萘醌和PQ孵育可引发人神经母细胞瘤细胞系的凋亡。用致死浓度的PQ处理SK-N-SH细胞可在6小时内促进ROS生成。该处理还促进了8-羟基脱氧鸟苷的形成、p53激活、Bax/Bcl-2比值升高、线粒体膜电位降低以及随后caspase-9和caspase-3的激活，推测ROS生成、DNA损伤和线粒体功能障碍是PQ触发SK-N-SH细胞凋亡的关键过程。对SK-N-SH细胞进行PQ处理可提高4-羟基壬烯醛（HNE）的水平，HNE是一种由脂质过氧化产生的细胞毒性反应性醛。用PQ和HNE处理还会降低细胞内总谷胱甘肽和还原型谷胱甘肽的水平，而分别用细胞可渗透的谷胱甘肽类似物和谷胱甘肽消耗剂预处理可改善和加剧HNE引起的损伤。此外，用PQ和HNE处理会降低蛋白酶体的蛋白水解活性，表明抗氧化能力的降低对ROS介导的神经母细胞瘤细胞凋亡有一定作用。我们对17种细胞的比较分析表明，PQ还原酶与NAD(P)H：醌氧化还原酶1（NQO1）活性之间呈正相关。此外，NQO1的过表达和敲低分别通过PQ氧化还原循环增加和降低了ROS生成以及醌毒性。此外，用PQ和HNE处理会上调NQO1的表达。综上所述，PQ暴露通过上调NQO1并加速其氧化还原循环，在神经母细胞瘤细胞中产生大量ROS，随后激活ROS依赖性凋亡机制。
