Aizenman E, Stout A K, Hartnett K A, Dineley K E, McLaughlin B, Reynolds I J
Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, USA.
J Neurochem. 2000 Nov;75(5):1878-88. doi: 10.1046/j.1471-4159.2000.0751878.x.
The membrane-permeant oxidizing agent 2,2'-dithiodipyridine (DTDP) can induce Zn(2+) release from metalloproteins in cell-free systems. Here, we report that brief exposure to DTDP triggers apoptotic cell death in cultured neurons, detected by the presence of both DNA laddering and asymmetric chromatin formation. Neuronal death was blocked by increased extracellular potassium levels, by tetraethylammonium, and by the broad-spectrum cysteine protease inhibitor butoxy-carbonyl-aspartate-fluoromethylketone. N,N,N', N'-Tetrakis-(2-pyridylmethyl)ethylenediamine (TPEN) and other cell-permeant metal chelators also effectively blocked DTDP-induced toxicity in neurons. Cell death, however, was not abolished by the NMDA receptor blocker MK-801, by the intracellular calcium release antagonist dantrolene, or by high concentrations of ryanodine. DTDP generated increases in fluorescence signals in cultured neurons loaded with the zinc-selective dye Newport Green. The fluorescence signals following DTDP treatment also increased in fura-2- and magfura-2-loaded neurons. These responses were completely reversed by TPEN, consistent with a DTDP-mediated increase in intracellular free Zn(2+) concentrations. Our studies suggest that under conditions of oxidative stress, Zn(2+) released from intracellular stores may contribute to the initiation of neuronal apoptosis.
膜通透性氧化剂2,2'-二硫代二吡啶（DTDP）可在无细胞体系中诱导金属蛋白释放锌离子（Zn²⁺）。在此，我们报告短暂暴露于DTDP会引发培养神经元的凋亡性细胞死亡，这可通过DNA梯状条带和不对称染色质形成来检测。细胞外钾离子浓度升高、四乙铵以及广谱半胱氨酸蛋白酶抑制剂丁氧羰基天冬氨酸氟甲基酮可阻断神经元死亡。N,N,N',N'-四（2 - 吡啶甲基）乙二胺（TPEN）和其他细胞通透性金属螯合剂也能有效阻断DTDP诱导的神经元毒性。然而，N - 甲基 - D - 天冬氨酸（NMDA）受体阻滞剂MK - 801、细胞内钙释放拮抗剂丹曲林或高浓度的ryanodine并不能消除细胞死亡。DTDP使加载了锌选择性染料纽波特绿的培养神经元中的荧光信号增强。在加载了fura - 2和magfura - 2的神经元中，DTDP处理后的荧光信号也增强。这些反应被TPEN完全逆转，这与DTDP介导的细胞内游离锌离子（Zn²⁺）浓度增加一致。我们的研究表明，在氧化应激条件下，从细胞内储存释放的锌离子（Zn²⁺）可能有助于启动神经元凋亡。
