Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Extremadura, 06071 Badajoz, Spain.
Apoptosis. 2012 Nov;17(11):1170-81. doi: 10.1007/s10495-012-0760-z.
The persistent xenobiotic agent 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induces neurotoxic effects that alters neurodevelopment and behavior both during development and adulthood. There are many ongoing efforts to determine the molecular mechanisms of TCDD-mediated neurotoxicity, the signaling pathways involved and its molecular targets in neurons. In this work, we have used SHSY5Y human neuroblastoma cells to characterize the TCDD-induced toxicity. TCDD produces a loss of viability linked to an increased caspase-3 activity, PARP-1 fragmentation, DNA laddering, nuclear fragmentation and hypodiploid (apoptotic) DNA content, in a similar way than staurosporine, a prototypical molecule of apoptosis induction. In addition, TCDD produces a decrease of mitochondrial membrane potential and an increase of intracellular calcium concentration (P < 0.05). Finally, based on the high lipophilic properties of the dioxin, we test the TCDD effect on the membrane integrity using sarcoplasmic reticulum vesicles as a model. TCDD produces calcium efflux through the membrane and an anisotropy decrease (P < 0.05) that reflects an increase in membrane fluidity. Altogether these results support the hypothesis that TCDD toxicity in SHSY5Y neuroblastoma cells provokes the disruption of calcium homeostasis, probably affecting membrane structural integrity, leading to an apoptotic process.
持久性外来化学物质 2,3,7,8-四氯二苯并对二恶英（TCDD）会引起神经毒性作用，这种作用会在发育和成年期改变神经发育和行为。目前有许多正在进行的努力旨在确定 TCDD 介导的神经毒性的分子机制、涉及的信号通路及其在神经元中的分子靶标。在这项工作中，我们使用 SHSY5Y 人神经母细胞瘤细胞来表征 TCDD 诱导的毒性。TCDD 产生与 caspase-3 活性增加、PARP-1 片段化、DNA 梯状条带、核片段化和低倍体（凋亡）DNA 含量相关的活力丧失，这与凋亡诱导的典型分子星孢菌素相似。此外，TCDD 还会降低线粒体膜电位并增加细胞内钙离子浓度（P<0.05）。最后，基于二恶英的高亲脂性，我们使用肌浆网囊泡作为模型测试 TCDD 对膜完整性的影响。TCDD 通过膜产生钙外流并降低各向异性（P<0.05），这反映了膜流动性的增加。总之，这些结果支持了 TCDD 在 SHSY5Y 神经母细胞瘤细胞中的毒性会破坏钙稳态的假设，可能会影响膜结构的完整性，导致凋亡过程。
