Cyclooxygenase-2 inhibition protects cultured cerebellar granule neurons from glutamate-mediated cell death
Cyclooxygenase-2 inhibition protects cultured cerebellar granule neurons from glutamate-mediated cell death
复制标题
DOI：
10.1089/089771502753754091
复制
发表时间：
2002-05-01
影响因子：
4.2
通讯作者：
Marini, AM
中科院分区：
文献类型：
--
作者：
Strauss, KI;Marini, AM
对大脑的主要损伤会引发谷氨酸释放，从而可能导致兴奋性毒性，然后导致神经元细胞死亡。这一次级过程由体内 N-甲基-D-天冬氨酸 (NMDA) 和非 NMDA 受体介导，并且需要新的基因表达。脑损伤后，神经元环氧合酶 2 (COX2) 表达通过谷氨酸能和炎症机制上调。 COX2 的产物是生物活性前列腺素和活性氧，可能在神经元存活中发挥作用。本研究利用培养的小脑颗粒神经元（体外第 8 天）探讨神经元 COX2 在谷氨酸兴奋毒性中的作用。用兴奋毒性浓度的谷氨酸或红藻氨酸处理可短暂诱导 COX2 mRNA（6 小时时分别为两倍和三倍，p < 0.05，Dunnett）和前列腺素产生（30 分钟时分别为五倍和六倍，p < 0.05，Dunnett）。 COX2 诱导在这些兴奋性氨基酸的毒性浓度下达到峰值。令人惊讶的是，NMDA、L-quisqualate 和 trans-ACPD 在任何测试浓度下均不会诱导 COX2 mRNA。谷氨酸受体拮抗剂 NBQX（5 μM，AMPA/红藻氨酸受体）完全抑制红藻氨酸诱导的 COX2 mRNA 并部分抑制谷氨酸诱导的 COX2（p < 0.05，Dunnett）。其他谷氨酸受体拮抗剂，例如 MK-801（1 μM，NMDA 受体）或 MCPG（500 μM，1 类代谢型受体），部分减弱谷氨酸诱导的 COX2 mRNA。这些拮抗剂均降低稳态 COX2 mRNA（p < 0.05，Dunnett）。为了确定COX2是否可能是兴奋性毒性细胞死亡的效应子，在谷氨酸攻击之前，用COX2特异性酶抑制剂DFU（5,5-二甲基-3-(3-氟苯基)-4-(4-甲基磺酰基)苯基-2(H-5)-呋喃酮）对小脑颗粒细胞进行预处理（24小时）。 DFU（1 至 1000 nM）完全保护培养的神经元免受谷氨酸介导的神经毒性。未观察到对 NMDA 介导的神经毒性有约 50% 的保护，但没有观察到对红藻氨酸介导的神经毒性的保护。因此，谷氨酸介导的 COX2 诱导导致兴奋性神经元死亡。这些结果表明谷氨酸、NMDA 和红藻氨酸神经毒性涉及不同的兴奋性毒性途径，并且谷氨酸和 NMDA 途径可能在 COX2 水平上交叉。
Primary insults to the brain can initiate glutamate release that may result in excitotoxicity followed by neuronal cell death. This secondary process is mediated by both N-methyl-D-aspartate (NMDA) and non-NMDA receptors in vivo and requires new gene expression. Neuronal cyclooxygenase-2 (COX2) expression is upregulated following brain insults, via glutamatergic and inflammatory mechanisms. The products of COX2 are bioactive prostanoids and reactive oxygen species that may play a role in neuronal survival. This study explores the role of neuronal COX2 in glutamate excitotoxicity using cultured cerebellar granule neurons (day 8 in vitro). Treatment with excitotoxic concentrations of glutamate or kainate transiently induced COX2 mRNA (two- and threefold at 6 h, respectively,p < 0.05, Dunnett) and prostaglandin production (five- and sixfold at 30 min, respectively, p < 0.05, Dunnett). COX2 induction peaked at toxic concentrations of these excitatory amino acids. Surprisingly, NMDA, L-quisqualate, and trans-ACPD did not induce COX2 mRNA at any concentration tested. The glutamate receptor antagonist NBQX (5 muM, AMPA/kainate receptor) completely inhibited kainate-induced COX2 mRNA and partially inhibited glutamate-induced COX2 (p < 0.05, Dunnett). Other glutamate receptor antagonists, such as MK-801 (1 muM, NMDA receptor) or MCPG (500 muM, class 1 metabotropic receptors), partially attenuated glutamate-induced COX2 mRNA. These antagonists all reduced steady-state COX2 mRNA (p < 0.05, Dunnett). To determine whether COX2 might be an effector of excitotoxic cell death, cerebellar granule cells were pretreated (24 h) with the COX2-specific enzyme inhibitor, DFU (5,5-dimethyl-3-(3-fluorophenyl)-4-(4-methylsulphonyl) phenyl-2(H-5)-furanone) prior to glutamate challenge. DFU (1 to 1000 nM) completely protected cultured neurons from glutamate-mediated neurotoxicity. Approximately 50% protection from NMDA-mediated neurotoxicity, and no protection from kainate-mediated neurotoxicity was observed. Therefore, glutamate-mediated COX2 induction contributes to excitotoxic neuronal death. These results suggest that glutamate, NMDA, and kainate neurotoxicity involve distinct excitotoxic pathways, and that the glutamate and NMDA pathways may intersect at the level of COX2.