Calpain activation and Na+/Ca2+ exchanger degradation occur downstream of calcium deregulation in hippocampal neurons exposed to excitotoxic glutamate.
Calpain activation and Na+/Ca2+ exchanger degradation occur downstream of calcium deregulation in hippocampal neurons exposed to excitotoxic glutamate.
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DOI：
10.1002/jnr.22295
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发表时间：
2010-05-01
影响因子：
4.2
通讯作者：
Brustovetsky, Nickolay
中科院分区：
文献类型：
--
作者：
Brustovetsky, Tatiana;Bolshakov, Alexey;Brustovetsky, Nickolay
迟发性钙失调（DCD）在谷氨酸兴奋性毒性中起重要作用，谷氨酸兴奋性毒性是中风、创伤性脑损伤和各种神经退行性变的主要有害因素。在本研究中，我们研究了钙蛋白酶激活和Na+/Ca 2+交换（NCX）降解的DCD和兴奋性毒性细胞死亡在培养的海马神经元的作用。神经元暴露于谷氨酸引起DCD伴随着二次线粒体去极化。通过检测NCX同种型3（NCX 3）降解产物证实钙蛋白酶的激活。NCX异构体1（NCX 1）的降解低于蛋白质印迹法的检测限。仅在与谷氨酸盐孵育1小时后检测到NCX 3的降解，而DCD平均在谷氨酸盐施用后15分钟内发生。钙蛋白酶抑制剂钙肽酶，显着减弱NCX 3降解，但未能抑制DCD和兴奋性毒性神经元死亡。钙蛋白酶抑制剂I、III和VI也未能影响DCD和谷氨酸诱导的神经元死亡。另一方面，MK 801，一种谷氨酸受体的NMDA亚型的抑制剂，在最初的谷氨酸诱导的胞质Ca 2+跳跃后不久加入，完全阻止了DCD和钙蛋白酶的激活，并强烈保护神经元免受兴奋性毒性。两者合计，我们的研究结果表明，在谷氨酸处理的海马神经元，胞质Ca 2+的初始增加之前DCD是不足以持续钙蛋白酶激活，这最有可能发生在DCD的下游。
Delayed calcium deregulation (DCD) plays an essential role in glutamate excitotoxicity, a major detrimental factor in stroke, traumatic brain injury, and various neurodegenerations. In the present study, we examined the role of calpain activation and Na+/Ca2+ exchanger (NCX) degradation in DCD and excitotoxic cell death in cultured hippocampal neurons. Exposure of neurons to glutamate caused DCD accompanied by secondary mitochondrial depolarization. Activation of calpain was evidenced by detecting NCX isoform 3 (NCX3) degradation products. Degradation of NCX isoform 1 (NCX1) was below the detection limit of western blotting. Degradation of NCX3 was detected only after an hour of incubation with glutamate, while DCD occurred on average within 15 minutes after glutamate application. Calpeptin, an inhibitor of calpain, significantly attenuated NCX3 degradation but failed to inhibit DCD and excitotoxic neuronal death. Calpain inhibitors I, III, and VI also failed to influence DCD and glutamate-induced neuronal death. On the other hand, MK801, an inhibitor of the NMDA-subtype of glutamate receptors, added shortly after the initial glutamate-induced jump in cytosolic Ca2+, completely prevented DCD and activation of calpain and strongly protected neurons against excitotoxicity. Taken together, our results suggest that, in glutamate-treated hippocampal neurons, the initial increase in cytosolic Ca2+ that precedes DCD is insufficient for sustained calpain activation, which most likely occurs downstream of DCD.
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影响因子：
4.7
作者：
Bevers, Matthew B.;Lawrence, Eric;Neumar, Robert W.
通讯作者：
Neumar, Robert W.
影响因子：
12.4
作者：
Araujo, I. M.;Carreira, B. P.;Carvalho, C. M.
通讯作者：
Carvalho, C. M.
影响因子：
3.6
作者：
Dineley, KE;Malaiyandi, LM;Reynolds, IJ
通讯作者：
Reynolds, IJ
影响因子：
4.7
作者：
Kiedrowski, L;Czyz, A;Lytton, J
通讯作者：
Lytton, J
影响因子：
5.3
作者：
Li, Viacheslav;Brustovetsky, Tatiana;Brustovetsky, Nickolay
通讯作者：
Brustovetsky, Nickolay