The PERK-eIF2α signaling pathway is involved in TCDD-induced ER stress in PC12 cells
The PERK-eIF2α signaling pathway is involved in TCDD-induced ER stress in PC12 cells
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PERK-eIF2 α信号通路参与TCDD诱导的PC12细胞内质网应激
DOI：
10.1016/j.neuro.2014.06.005
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发表时间：
2014-09-01
期刊：
影响因子：
3.4
通讯作者：
Xu, Guangfei
中科院分区：
文献类型：
--
作者：
Duan, Zhiqing;Zhao, Jianya;Xu, Guangfei
研究表明，2，3，7，8-四氯二苯并-对二恶英(TCDD)可诱导神经细胞凋亡。然而，这是否是内质网(ER)应激介导的细胞凋亡的结果仍不清楚。在这项研究中，我们确定了内质网应激在TCDD诱导的嗜铬细胞瘤(PC12)细胞和原代神经元凋亡中是否起作用。将PC12细胞暴露于不同浓度的TCDD(1、10、100、200或500 nM)中不同时间(1、3、6、12或24小时)。TCDD浓度远高于10 nM(100、200或500 nM)时，葡萄糖调节蛋白(GRP78)和C/EBP同源蛋白(CHOP)水平显著增加，这是内质网应激的标志。用不同浓度的TCDD(1、10、50、200 nM)处理PC12细胞和原代神经元24 h，观察TCDD对PC12细胞和原代神经元内质网形态的影响，并用透射电子显微镜观察高浓度TCDD对PC12细胞和原代神经元ER的影响。此外，TCDD诱导的内质网应激显著促进未折叠蛋白反应(UPR)的感受器PKR样ERK(PERK)及其下游靶标真核细胞翻译起始因子2cc(eIF2α)的激活；相反，TCDD对另两个UPR感受器肌醇需求酶1(IRE1)和激活转录因子6(ATF6)似乎没有影响。重要的是，TCDD在处理6-24小时后显著抑制了elF2α的磷酸化，并触发了PC12细胞的凋亡。Salubrine激活PERK-elF2α通路，显著增强PC12细胞中eIF2α的磷酸化，并减轻TCDD诱导的细胞死亡。相反，使用小干扰RNA敲除eIF2α显著增强了TCDD诱导的细胞死亡。综上所述，这些结果表明PERK-eIF2α通路在TCDD诱导的内质网应激和PC12细胞的凋亡中起重要作用。(C)2014 Elsevier Inc.保留所有权利。
Studies have shown that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induces apoptotic cell death in neuronal cells. However, whether this is the result of endoplasmic reticulum (ER) stress-mediated apoptosis remains unknown. In this study, we determined whether ER stress plays a role in the TCDD-induced apoptosis of pheochromocytoma (PC12) cells and primary neurons. PC12 cells were exposed to different TCDD concentrations (1, 10, 100, 200, or 500 nM) for varying lengths of time (1, 3, 6, 12, or 24 h). TCDD concentrations much higher than 10 nM (100, 200, or 500 nM) markedly increased glucose-regulated protein (GRP78) and C/EBP homologous protein (CHOP) levels, which are hallmarks of ER stress. We also evaluated the effects of TCDD on ER morphology in PC12 cells and primary neurons that were treated with different TCDD concentrations (1, 10, 50, or 200 nM) for 24 h. Ultrastructural ER alterations were observed with transmission electron microscopy in PC12 cells and primary neurons treated with high concentrations of TCDD. Furthermore, TCDD-induced ER stress significantly promoted the activation of the PKR-like ER kinase (PERK), a sensor for the unfolded protein response (UPR), and its downstream target eukaryotic translation initiation factor 2 cc (eIF2 alpha.); in contrast, TCDD did not appear to affect inositol-requiring enzyme 1 (IRE1) and activating transcription factor 6 (ATF6), two other UPR sensors. Importantly, TCDD significantly inhibited elF2 alpha phosphorylation and triggered apoptosis in PC12 cells after 6-24 h of treatment. Salubrinal, which activates the PERK-elF2 alpha pathway, significantly enhanced eIF2 alpha phosphorylation in PC12 cells and attenuated the TCDD-induced cell death. In contrast, knocking down eIF2 alpha using small interfering RNA markedly enhanced TCDD-induced cell death. Together, these results indicate that the PERK-eIF2 alpha pathway plays an important role in TCDD-induced ER stress and apoptosis in PC12 cells. (C) 2014 Elsevier Inc. All rights reserved.