Development of spontaneous neuropathy in NF-κBp50-deficient mice by calcineurin-signal involving impaired NF-κB activation
Development of spontaneous neuropathy in NF-κBp50-deficient mice by calcineurin-signal involving impaired NF-κB activation
复制标题
DOI：
--
复制
发表时间：
2011-08
期刊：
影响因子：
2.2
通讯作者：
Tomoko Nakamura-Yanagidaira;Yasuko Takahashi;K. Sano;T. Murata;Takuma Hayashi
中科院分区：
文献类型：
--
作者：
Tomoko Nakamura-Yanagidaira;Yasuko Takahashi;K. Sano;T. Murata;Takuma Hayashi
目的核转录因子-κ B（NF-κB）/Rel家族参与神经细胞的死亡和存活。以前，我们报道了NF-κ Bp 50缺陷（p50缺陷）小鼠表现出许多类似于人类正常眼压性青光眼（NTG）的特征。人NTG的发育机制尚不清楚，根治性治疗尚未建立。我们的目的是阐明信号级联介导的自发性视神经病变的p50缺陷小鼠作为模型的NTG。方法采用免疫印迹法（WB）和荧光素酶报告基因检测p50基因缺陷小鼠视网膜神经节细胞（RGC-5）中促凋亡因子的表达和激活，并与野生型和p50基因缺陷小鼠视网膜神经节细胞（RGC-5）进行比较。此外，我们测试了化学试剂（美金刚，洛美利嗪，他克莫司）对N-甲基-D-天冬氨酸（NMDA）敏感的RGC损伤的神经保护作用，根据RGC-5细胞的体外实验。为了阐明NF-κ B介导的死亡信号，通过组织病理学研究来检测化学试剂对自发性视神经病变的影响。结果WB实验和荧光素酶报告基因检测显示，NF-κ B诱导的BCL 2相关X蛋白（Bax）和促凋亡因子活化的caspase 3在p50缺陷小鼠视网膜和NMDA处理的RGC-5细胞中均有表达。此外，在p50缺陷小鼠的视网膜以及NMDA处理的RGC-5细胞中检测到了钙调神经磷酸酶（CaN）的组成性活性形式，这已被报道会导致细胞凋亡。他克莫司预处理显著保护RGC-5细胞免受NMDA诱导的神经毒性，然后通过长期给药他克莫司显著减少p50缺陷小鼠中自发RGC死亡和视神经退行性变化。培养的RGC-5细胞实验支持p50缺陷小鼠的组织学检查结果，表明CaN激活导致NF-κ B诱导的Bax激活和caspase 3激活，并介导p50缺陷小鼠的自发性视神经病变。结论长期应用他克莫司可明显减轻p50基因缺陷小鼠的自发性视神经病变。我们证明了一个潜在的CaN信号级联，自发诱导年龄依赖性RGC死亡和p50缺陷小鼠的退行性视神经变化。
Purpose The transcriptional regulator, nuclear factor-kappa B (NF-κB)/Rel family are involved in neuronal cell death and survival. Previously, we reported that NF-κBp50-deficient (p50-deficient) mice exhibit many features resembling human normal tension glaucoma (NTG). The developmental mechanism of human NTG is not clearly understood, and a radical curative treatment has yet to be established. Our aim is to elucidate the signal cascade which mediates the spontaneous optic neuropathy in p50-deficient mice as a model of NTG. Methods To demonstrate the expression and activation of pro-apoptotic factors, which mediate the death of retinal ganglion cells (RGCs) in p50-deficient mice, western blot (WB) and luciferase reporter assays with retinas from p50-deficient and wild type mice, and cultured RGC-5 cells were performed. Furthermore, we tested the neuroprotective effects of chemical reagents (memantine, lomerizine, and tacrolimus) against N-methyl-D-aspartate (NMDA)-susceptible RGC damage according to in vitro experiments with RGC-5 cells. To elucidate the NF-κB-mediated death signaling, the effects of chemical reagents on spontaneous optic neuropathy were examined by histopathological studies. Results WB experiments and luciferase reporter assays showed that NF-κB-inducible BCL2-associated X protein (Bax) and a pro-apoptotic factor, activated caspase 3 were expressed in the retina of p50-deficient mice as well as NMDA-treated RGC-5 cells. Further, the constitutivelyactivecleaved forms of calcineurin (CaN), which havebeen reported to lead to apoptosis, were detected in the retina of p50-deficient mice as well as NMDA-treated RGC-5 cells. Pre-treatment with tacrolimus markedlyprotected RGC-5 cells from NMDA-induced neurotoxicity, and then both spontaneous RGC death and degenerative changes to the optic nerve in p50-deficient mice were significantlyreduced by the chronic administration of tacrolimus. The experiments with cultured RGC-5 cells supported the results of histological examinations with p50-deficient mice, suggesting that CaN activation leads to NF-κB-induced Bax activation and caspase 3 activation, and mediates spontaneous optic neuropathy in p50-deficient mice. Conclusions Research findings show that the chronic administration of tacrolimus significantly reduces spontaneous optic neuropathy in p50-deficient mice. We demonstrated a potential CaN signal cascade, which spontaneously induces age-dependent RGC death and degenerative optic nerve changes in p50-deficient mice.