Nath R, Probert A, McGinnis K M, Wang K K
Department of Neuroscience Therapeutics, Parke-Davis Pharmaceutical Research, Warner-Lambert Company, Ann Arbor, Michigan 48105, USA.
J Neurochem. 1998 Jul;71(1):186-95. doi: 10.1046/j.1471-4159.1998.71010186.x.
Caspase activation has been shown to be a critical step in several models of neuronal apoptosis such as staurosporine treatment of human neuroblastoma SH-SY5Y cells and potassium deprivation of rat cerebellar granule neurons. One common event is the appearance of caspase-mediated 120-kDa nonerythroid alpha-spectrin breakdown product (SBDP120). Second, inhibitors of the caspase family are effective blockers of such neuronal death. In this study, we report the appearance of caspase-mediated SBDP120 in excitotoxin-challenged fetal rat cerebrocortical neurons [N-methyl-D-aspartate (NMDA), alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid, and kainate] and rat cerebellar granule neurons (NMDA and kainate). A general caspase inhibitor, carbobenzoxy-Asp-CH2OC(O)-2,6-dichlorobenzene (Z-D-DCB), blocked the formation of SBDP120 under these conditions and attenuated the observed NMDA-induced lactate dehydrogenase (LDH) release in both cell types. Furthermore, hydrolytic activity toward a caspase-3-preferred synthetic peptide substrate, acetyl-DEVD-7-amido-4-methylcoumarin, was significantly elevated in NMDA-treated granule neurons. Lastly, oxygen-glucose deprivation (OGD)-challenged cerebrocortical cultures also showed the appearance of SBDP120. Again, Z-D-DCB blocked the SBDP120 formation as well as attenuated the LDH release from the OGD-challenged neurons. Taken together, the presence of caspase-specific SBDP120 and the neuroprotective effects of Z-D-DCB strongly suggest that caspase activation contributes at least in part to excitotoxin- and OGD-induced neuronal death.
在几种神经元凋亡模型中，如用星形孢菌素处理人神经母细胞瘤SH-SY5Y细胞以及剥夺大鼠小脑颗粒神经元的钾离子，半胱天冬酶激活已被证明是一个关键步骤。一个常见事件是半胱天冬酶介导的120-kDa非红细胞α-血影蛋白降解产物（SBDP120）的出现。其次，半胱天冬酶家族抑制剂是此类神经元死亡的有效阻滞剂。在本研究中，我们报告了在受兴奋性毒素攻击的胎鼠大脑皮质神经元 [N-甲基-D-天冬氨酸（NMDA）、α-氨基-3-羟基-5-甲基-4-异恶唑丙酸和海人藻酸] 和大鼠小脑颗粒神经元（NMDA和海人藻酸）中出现了半胱天冬酶介导的SBDP120。一种通用的半胱天冬酶抑制剂，苄氧羰基-天冬氨酸-CH2OC（O）-2,6-二氯苯（Z-D-DCB），在这些条件下阻断了SBDP120的形成，并减弱了在两种细胞类型中观察到的NMDA诱导的乳酸脱氢酶（LDH）释放。此外，在NMDA处理的颗粒神经元中，对半胱天冬酶-3偏好的合成肽底物乙酰-DEVD-7-氨基-4-甲基香豆素的水解活性显著升高。最后，氧糖剥夺（OGD）攻击的大脑皮质培养物也显示出SBDP120的出现。同样，Z-D-DCB阻断了SBDP120的形成，并减弱了OGD攻击神经元的LDH释放。综上所述，半胱天冬酶特异性SBDP120的存在以及Z-D-DCB的神经保护作用强烈表明，半胱天冬酶激活至少部分促成了兴奋性毒素和OGD诱导的神经元死亡。
