A decrease in phosphorylation of cAMP-response element-binding protein (CREBP) promotes retinal degeneration.
A decrease in phosphorylation of cAMP-response element-binding protein (CREBP) promotes retinal degeneration.
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DOI：
10.1016/j.exer.2011.03.017
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发表时间：
2011-06
影响因子：
3.4
通讯作者：
Chintala, Shravan K.
中科院分区：
文献类型：
--
作者：
Mali, Raghuveer S.;Zhang, Xiao M.;Chintala, Shravan K.
由N-甲基-D-天冬氨酸（NMDA）或红藻氨酸（KA）诱导的兴奋性毒性促进视网膜神经节细胞（RGC）的不可逆损失。尽管兴奋性毒性细胞死亡的细胞内信号传导机制尚不清楚，但最近对视网膜的研究表明，NMDA通过增加环AMP（cAMP）反应元件（CRE）结合蛋白（CREBP）的磷酸化来促进RGC死亡，而对中枢神经系统的研究表明，KA通过减少CREBP的磷酸化来促进神经元细胞死亡，提示CREBP可引起依赖于兴奋性毒物的双重反应。有趣的是，CREBP在KA介导的RGC死亡中的作用尚未研究。因此，通过使用兴奋性毒性的动物模型，本研究的目的是调查是否兴奋性毒性诱导RGC死亡减少Ser 133-CREBP在视网膜中。通过玻璃体内注射20 nmol红藻氨酸（KA）诱导CD-1小鼠的RGCs死亡。CREBP水平的降低通过免疫组织化学、蛋白质印迹分析和电泳迁移率凝胶位移测定（EMSA）来确定。免疫组织化学分析表明CREBP在CD-1小鼠的神经节细胞层（GCL）和内核层（INL）的细胞核中组成性表达。KA注射后6 h，GCL中Ser 133-CREBP的核定位减少。KA注射后24 h，GCL和INL中Ser 133-CREBP进一步降低，并且Ser 133-CREBP的降低与RGCs和无长突细胞的凋亡相关。Western blot分析表明，KA降低视网膜蛋白提取物中Ser 133-CREBP的水平。EMSA分析表明，KA也减少了Ser 133-CREBP与CRE共有寡核苷酸的结合。相反，玻璃体内注射非NMDA谷氨酸受体拮抗剂CNQX，恢复KA诱导的GCL和INL中Ser 133-CREBP的减少，并抑制RGCs和无长突细胞的丢失。这些结果首次表明KA通过减少视网膜中Ser 133-CREBP的磷酸化而促进视网膜变性。
Excitotoxicity, induced either by N-Methyl-D-aspartate (NMDA) or kainic acid (KA), promotes irreversible loss of retinal ganglion cells (RGCs). Although the intracellular signaling mechanisms underlying excitotoxic cell death are still unclear, recent studies on the retina indicate that NMDA promotes RGC death by increasing phosphorylation of cyclic AMP (cAMP) response element (CRE)-binding protein (CREBP), while studies on the central nervous system indicate that KA promotes neuronal cell death by decreasing phosphorylation of CREBP, suggesting that CREBP can elicit dual responses depending on the excitotoxic-agent. Interestingly, the role of CREBP in KA-mediated death of RGCs has not been investigated. Therefore, by using an animal model of excitotoxicity, the aim of this study was to investigate whether excitotoxicity induces RGC death by decreasing Ser133-CREBP in the retina. Death of RGCs was induced in CD-1 mice by an intravitreal injection of 20 n moles of kainic acid (KA). Decrease in CREBP levels was determined by immunohistochemistry, western blot analysis, and electrophoretic mobility gel shift assays (EMSAs). Immunohistochemical analysis indicated that CREBP was constitutively expressed in the nuclei of cells both in the ganglion cell layer (GCL) and in the inner nuclear layer (INL) of CD-1 mice. At 6 h after KA injection, nuclear localization of Ser133-CREBP was decreased in the GCL. At 24 h after KA injection, Ser133-CREBP was decreased further in GCL and the INL, and a decrease in Ser133-CREBP correlated with apoptotic death of RGCs and amacrine cells. Western blot analysis indicated that KA decreased Ser133-CREBP levels in retinal protein extracts. EMSA assays indicated that KA also reduced the binding of Ser133-CREBP to CRE consensus oligonucleotides. In contrast, intravitreal injection of CNQX, a non-NMDA glutamate receptor antagonist, restored the KA-induced decrease in Ser133-CREBP both in in the GCL and INL, and inhibited loss of RGCs and amacrine cells. These results, for the first time, suggest that KA promotes retinal degeneration by reducing phosphorylation of Ser133-CREBP in the retina.
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DOI：
10.1073/pnas.83.18.6682
发表时间：
1986-09-01
影响因子：
11.1
作者：
MONTMINY, MR;SEVARINO, KA;GOODMAN, RH
通讯作者：
GOODMAN, RH
影响因子：
5.3
作者：
Mabuchi, T;Kitagawa, K;Matsumoto, M
通讯作者：
Matsumoto, M
影响因子：
1.9
作者：
SILIPRANDI, R;CANELLA, R;VANTINI, G
通讯作者：
VANTINI, G
影响因子：
6.1
作者：
Hansen, HH;Briem, T;Ikonomidou, C
通讯作者：
Ikonomidou, C
影响因子：
4.8
作者：
Chintala, SK;Sawaya, R;Rao, JS
通讯作者：
Rao, JS