Guemez-Gamboa Alicia, Morán Julio
Departamento de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México D.F., México.
J Neurosci Res. 2009 Aug 15;87(11):2531-40. doi: 10.1002/jnr.22079.
Neuronal apoptotic death involves the participation of reactive oxygen species (ROS), but their sources have not been completely elucidated. Previous studies have demonstrated that the ROS-producing enzyme NADPH oxidase is present in neuronal cells and that this enzyme could participate in the apoptotic neuronal death. Cerebellar granule neurons (CGN) undergo apoptosis when cells are transferred from a medium with 25 mM KCl (K25) to a 5 mM KCl (K5) medium or when they are treated with staurosporine (ST). Under these conditions, apoptotic death of CGN is dependent on ROS production. In this study, we evaluated the role of NOX2, an NADPH oxidase homolog, in the apoptotic death of CGN induced by two different conditions. In CGN from NOX2-deficient (ko) mice, a significantly lower rate of apoptotic death occurs compared with wild-type (wt) CGN. Also, caspase-3 activation, NADPH oxidase activity, and superoxide anion production induced by ST were markedly lower in ko neurons than in wt CGN. In contrast to the case with ST, when CGN were treated with K5, no differences were observed between ko and wt cells in any of the parameters measured. However, all NADPH oxidase inhibitors tested noticeably reduced cell death and apoptotic parameters induced by K5 in both wt and ko CGN. These results suggest that NOX2 could be necessary for apoptotic death induced by ST, but not by K5, which could require other member of the NOX family in the apoptotic process.
神经元凋亡性死亡涉及活性氧（ROS）的参与，但其来源尚未完全阐明。先前的研究表明，产生活性氧的酶——烟酰胺腺嘌呤二核苷酸磷酸（NADPH）氧化酶存在于神经元细胞中，且该酶可能参与神经元的凋亡性死亡。当小脑颗粒神经元（CGN）从含有25 mM氯化钾（K25）的培养基转移至5 mM氯化钾（K5）培养基中，或用星形孢菌素（ST）处理时，会发生凋亡。在这些条件下，CGN的凋亡性死亡依赖于活性氧的产生。在本研究中，我们评估了NADPH氧化酶同系物NOX2在两种不同条件诱导的CGN凋亡性死亡中的作用。在来自NOX2缺陷（ko）小鼠的CGN中，与野生型（wt）CGN相比，凋亡性死亡率显著降低。此外，ko神经元中由ST诱导的半胱天冬酶-3激活、NADPH氧化酶活性和超氧阴离子产生明显低于wt CGN。与ST处理的情况相反，当CGN用K5处理时，在测量的任何参数中，ko细胞和wt细胞之间均未观察到差异。然而，所有测试的NADPH氧化酶抑制剂均显著降低了wt和ko CGN中由K5诱导的细胞死亡和凋亡参数。这些结果表明，NOX2可能是ST诱导的凋亡性死亡所必需的，但不是K5诱导的凋亡性死亡所必需的，K5诱导的凋亡过程可能需要NOX家族的其他成员。
