Lisek Malwina, Stragierowicz Joanna, Guo Feng, Prosseda Philipp P, Wiktorska Magdalena, Ferenc Bozena, Kilanowicz Anna, Zylinska Ludmila, Boczek Tomasz
Department of Molecular Neurochemistry, Medical University of Lodz, 92215 Lodz, Poland.
Department of Toxicology, Medical University of Lodz, 90151 Lodz, Poland.
Oxid Med Cell Longev. 2020 Jun 26;2020:2479234. doi: 10.1155/2020/2479234. eCollection 2020.
Hexachloronaphthalene (PCN67) is one of the most toxic among polychlorinated naphthalenes. Despite the known high bioaccumulation and persistence of PCN67 in the environment, it is still unclear to what extent exposure to these substances may interfere with normal neuronal physiology and lead to neurotoxicity. Therefore, the primary goal of this study was to assess the effect of PCN67 in neuronal models. Neuronal death was assessed upon PCN67 treatment using differentiated PC12 cells and primary hippocampal neurons. At 72 h postexposure, cell viability assays showed an IC value of 0.35 g/ml and dose-dependent damage of neurites and concomitant downregulation of neurofilaments L and M. Moreover, we found that younger primary neurons (DIV4) were much more sensitive to PCN67 toxicity than mature cultures (DIV14). Our comprehensive analysis indicated that the application of PCN67 at the IC concentration caused necrosis, which was reflected by an increase in LDH release, HMGB1 protein export to the cytosol, nuclear swelling, and loss of homeostatic control of energy balance. The blockage of mitochondrial calcium uniporter partially rescued the cell viability, loss of mitochondrial membrane potential ( ), and the overproduction of reactive oxygen species, suggesting that the underlying mechanism of neurotoxicity involved mitochondrial calcium accumulation. Increased lipid peroxidation as a consequence of oxidative stress was additionally seen for 0.1 g/ml of PCN67, while this concentration did not affect and plasma membrane permeability. Our results show for the first time that neuronal mitochondria act as a target for PCN67 and indicate that exposure to this drug may result in neuron loss via mitochondrial-dependent mechanisms.
六氯萘（PCN67）是多氯萘中毒性最强的物质之一。尽管已知PCN67在环境中具有高生物累积性和持久性，但这些物质的暴露在多大程度上会干扰正常神经元生理并导致神经毒性仍不清楚。因此，本研究的主要目的是评估PCN67在神经元模型中的作用。使用分化的PC12细胞和原代海马神经元，在PCN67处理后评估神经元死亡情况。暴露72小时后，细胞活力测定显示IC值为0.35μg/ml，神经突出现剂量依赖性损伤，同时神经丝L和M下调。此外，我们发现较年轻的原代神经元（DIV4）对PCN67毒性比成熟培养物（DIV14）敏感得多。我们的综合分析表明，以IC浓度应用PCN67会导致坏死，这表现为乳酸脱氢酶释放增加、HMGB1蛋白输出到细胞质、核肿胀以及能量平衡稳态控制丧失。线粒体钙单向转运体的阻断部分挽救了细胞活力、线粒体膜电位丧失以及活性氧的过量产生，表明神经毒性的潜在机制涉及线粒体钙积累。对于0.1μg/ml的PCN67，还观察到氧化应激导致脂质过氧化增加，而该浓度不影响线粒体膜电位和质膜通透性。我们的结果首次表明神经元线粒体是PCN67的作用靶点，并表明接触该药物可能通过线粒体依赖性机制导致神经元丧失。
