Mechanisms of Cell Death Induced by the Mitochondrial Toxin 3-Nitropropionic Acid: Acute Excitotoxic Necrosis and Delayed Apoptosis
Mechanisms of Cell Death Induced by the Mitochondrial Toxin 3-Nitropropionic Acid: Acute Excitotoxic Necrosis and Delayed Apoptosis
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DOI：
10.1523/jneurosci.17-09-03064.1997
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发表时间：
1997-05
期刊：
影响因子：
--
通讯作者：
Z. Pang;J. Geddes
中科院分区：
文献类型：
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作者：
Z. Pang;J. Geddes
能量代谢受损可能在脑缺血后神经细胞死亡和迟发性神经退行性疾病中起重要作用。兴奋性坏死和细胞凋亡都与代谢损伤引起的细胞死亡有关。然而，决定细胞是否发生凋亡或坏死的因素尚不清楚。本研究用琥珀酸脱氢酶的自杀性抑制剂3-硝基丙酸(3-NP)诱导代谢损伤。用3-NP处理培养的大鼠海马神经元，可导致两种不同形态、药理和生化特征的细胞死亡。N-甲基-D-天冬氨酸受体拮抗剂MK-801(10μm)可完全阻止以细胞肿胀和核收缩为特征的快速坏死性细胞死亡，并可剂量依赖地增强细胞外低微摩尔水平的谷氨酸。MK-801不能减轻以核碎裂为特征的缓慢发展的细胞凋亡，但放线菌酮(1μg/ml)可阻止其发生。MK-801和放线菌亚胺联用对3-NP诱导的细胞死亡几乎完全有保护作用。用末端脱氧核苷酸转移酶介导的dUTP-X 3‘缺口末端标记技术检测到的DNA断裂是细胞凋亡的晚期事件，也发生在坏死细胞死亡之后。在3-NP诱导的神经元变性中，ATP耗竭是一个早期事件，谷氨酸加剧了ATP的下降。我们得出结论，3-NP可触发两种不同的细胞死亡途径：一种是NMDA受体激活引起的兴奋性毒性坏死，另一种是NMDA受体非依赖的迟发性细胞凋亡。轻微升高的细胞外谷氨酸水平将细胞死亡机制从凋亡转变为坏死。
Impaired energy metabolism may play an important role in neuronal cell death after brain ischemia and in late-onset neurodegenerative diseases. Both excitotoxic necrosis and apoptosis have been implicated in cell death induced by metabolic impairment. However, the factors that determine whether cells undergo apoptosis or necrosis are not known. In the present study, metabolic impairment was induced by 3-nitropropionic acid (3-NP), a suicide inhibitor of succinate dehydrogenase. Treatment of cultured rat hippocampal neurons with 3-NP resulted in two types of cell death with distinct morphological, pharmacological, and biochemical features. A rapid necrotic cell death, characterized by cell swelling and nuclear shrinkage, could be completely prevented by the NMDA receptor antagonist MK-801 (10 μm) and dose-dependently potentiated by low micromolar levels of extracellular glutamate. A slowly evolving apoptotic death, characterized by nuclear fragmentation, was not attenuated by MK-801 but was prevented by cycloheximide (1 μg/ml). The combination of MK-801 and cycloheximide resulted in an almost complete protection against 3-NP-induced cell death. DNA fragmentation, detected by the terminal deoxynucleotidyl transferase-mediated dUTP-X 3′ nick end-labeling technique, was a late event in apoptosis and also occurred after necrotic cell death. ATP depletion was an early event in the 3-NP-induced neuronal degeneration, and the decline in ATP was exacerbated by glutamate. We conclude that 3-NP triggers two separate cell death pathways: an excitotoxic necrosis as a result of NMDA receptor activation and a delayed apoptosis that is NMDA receptor-independent. Mildly elevated levels of extracellular glutamate shift the cell death mechanism from apoptosis to necrosis.