Chang Louis K, Schmidt Robert E, Johnson Eugene M
Washington University School of Medicine, Saint Louis, MO 63110, USA.
J Cell Biol. 2003 Jul 21;162(2):245-56. doi: 10.1083/jcb.200302109.
Mitochondrial release of cytochrome c in apoptotic cells activates caspases, which execute apoptotic cell death. However, the events themselves that culminate in caspase activation can have deleterious effects because caspase inhibitor-saved cells ultimately die in a caspase-independent manner. To determine what events may underlie this form of cell death, we examined bioenergetic changes in sympathetic neurons deprived of NGF in the presence of a broad-spectrum caspase inhibitor, boc-aspartyl-(OMe)-fluoromethylketone. Here, we report that NGF-deprived, boc-aspartyl-(OMe)-fluoromethylketone-saved neurons rely heavily on glycolysis for ATP generation and for survival. Second, the activity of F0F1 contributes to caspase-independent death, but has only a minor role in the maintenance of mitochondrial membrane potential, which is maintained primarily by electron transport. Third, permeability transition pore inhibition by cyclosporin A attenuates NGF deprivation-induced loss of mitochondrial proteins, suggesting that permeability transition pore opening may have a function in regulating the degradation of mitochondria after cytochrome c release. Identification of changes in caspase inhibitor-saved cells may provide the basis for rational strategies to augment the effectiveness of the therapeutic use of postmitochondrial interventions.
凋亡细胞中细胞色素c从线粒体释放会激活半胱天冬酶，后者执行凋亡性细胞死亡。然而，最终导致半胱天冬酶激活的这些事件本身可能具有有害作用，因为用半胱天冬酶抑制剂挽救的细胞最终会以一种不依赖半胱天冬酶的方式死亡。为了确定这种细胞死亡形式可能的潜在机制，我们在存在广谱半胱天冬酶抑制剂boc-天冬氨酸-（OMe）-氟甲基酮的情况下，检测了缺乏神经生长因子（NGF）的交感神经元的生物能量变化。在此，我们报告，缺乏NGF但被boc-天冬氨酸-（OMe）-氟甲基酮挽救的神经元严重依赖糖酵解来产生ATP并维持存活。其次，F0F1的活性促成不依赖半胱天冬酶的死亡，但在维持线粒体膜电位方面仅起次要作用，线粒体膜电位主要由电子传递维持。第三，环孢素A抑制通透性转换孔可减轻NGF剥夺诱导的线粒体蛋白丢失，这表明通透性转换孔开放可能在细胞色素c释放后调节线粒体降解中发挥作用。确定半胱天冬酶抑制剂挽救的细胞中的变化可能为合理策略提供基础，以增强线粒体后干预治疗用途的有效性。
