Contribution of mitogen-activated protein kinases to NMDA-induced neurotoxicity in the rat retina
Contribution of mitogen-activated protein kinases to NMDA-induced neurotoxicity in the rat retina
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DOI：
10.1016/j.brainres.2005.03.014
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发表时间：
2005-05-24
期刊：
影响因子：
2.9
通讯作者：
Ueno, S
中科院分区：
文献类型：
--
作者：
Munemasa, Y;Ohtani-Kaneko, R;Ueno, S
我们检测了丝裂原活化蛋白激酶（MAPKs）家族[细胞外信号调节激酶（ERK）， p38激酶（p38）和c-Jun n-末端激酶（JNK）]对n-甲基- d -天冬氨酸（NMDA）诱导的大鼠视网膜神经毒性的贡献。用末端脱氧核苷酸转移酶介导的dutp -生物素镍端标记法（TUNEL）染色检测视网膜神经节细胞层（RGCL）和内核层（INL）凋亡细胞死亡，从玻璃体内注射NMDA （100 nmol）后6 h开始，此后持续增加。Western blot分析显示，磷酸化MAPKs （p-MAPKs）在视网膜中的表达具有时间性：磷酸化ERK （p-ERK）在注射后1 h达到最大表达，磷酸化p38 （pp38）在注射后6 h达到最大表达，磷酸化JNK （p-JNK）在注射后6 h开始显著增加。免疫组织化学/TUNEL共定位研究表明，RGCL中p-JNK和p-p38阳性细胞经常呈TUNEL阳性，而p- erk阳性细胞很少呈TUNEL阳性。此外，通过tunel阳性细胞计数显示，JNK （0.2 nmol SP600125）和/或p38 （2.0 nmol SB203580）抑制剂与NMDA共同注射后12 h，可有效改善NMDA诱导的RGCL凋亡细胞损失。注射后7天的RGCL细胞计数和IPL厚度测量等形态学研究表明，这些抑制剂还能保护内视网膜。另一方面，ERK抑制剂（2.0 nmol U0126）不能抑制nmda诱导的RGCL细胞死亡，也不能抑制IPL变薄。这些结果表明JNK和p38在nmda诱导的RGCL细胞死亡中起促凋亡作用，而ERK不起作用。2005 Elsevier B.V.版权所有
We examined the contributions of the mitogen-activated protein kinases (MAPKs) family [extracellular signal-regulated kinase (ERK), p38 kinase (p38), and c-Jun N-terminal kinase (JNK)] to N-methyl-D-aspartate (NMDA)-induced neurotoxicity in the rat retina. Detection of apoptotic cell death in the retinal ganglion cell layer (RGCL) and the inner nuclear layer (INL) by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL) staining began 6 h after intravitreal NMDA (100 nmol) injection and continued to increase thereafter. Western blot analysis showed that phosphorylated MAPKs (p-MAPKs) were expressed in the retina following a temporal, manner: maximal expression of phosphorylated ERK (p-ERK) at 1 h, maximal expression of phosphorylated p38 (pp38) at 6 h, and beginning of phosphorylated JNK (p-JNK) significant increase at 6 It after injection. An immunohistochemical/TUNEL co-localization study showed that p-JNK- and p-p38-positive cells in the RGCL were frequently TUNEL-positive, whereas few p-ERK-positive cells were TUNEL-positive. Moreover, co-injection of inhibitors for JNK (0.2 mnol SP600125) and/or p38 (2.0 nmol SB203580) with NMDA was effective in ameliorating NMDA-induced apoptotic cell loss in the RGCL 12 h after injection, as shown by TUNEL-positive cell counts. These inhibitors also protected the inner retina as shown by morphometric studies such as cell counts in the RGCL and measurement of the IPL thickness 7 days after injection. On the other hand, an ERK inhibitor (2.0 nmol U0126) did not suppress NMDA-induced cell death in the RGCL nor thinning of the IPL. These findings suggest that JNK and p38 are proapoptotic in NMDA-induced cell death in the RGCL, but not ERK. 2005 Elsevier B.V. All rights reserved.