The endoplasmic reticulum is the central organelle within a eukaryotic cell where newly synthesized proteins are processed and properly folded. An excess of unfolded or mis-folded proteins induces ER stress signalling...The endoplasmic reticulum is the central organelle within a eukaryotic cell where newly synthesized proteins are processed and properly folded. An excess of unfolded or mis-folded proteins induces ER stress signalling pathways. Usually this means a pro-survival strategy for the cell, whereas under extended stress conditions the ER stress signalling pathways have a pro-apoptotic function. CK2 plays a key role in the regulation of the pro-survival as well as the proapoptotic ER stress signalling by directly modulating the activities of members of the ER stress signalling pathways by phosphorylation, regulating the expression of the key factors of the signalling pathways or binding to regulator proteins. The present review will summarize the state of the art in this new emerging field.展开更多
目的:探讨蛋白激酶RNA样ER激酶(protein kinase RNA-like ER kinase,PERK)信号通路介导的线粒体未折叠蛋白反应(mitochondrial unfolded protein response,mtUPR)在缺氧缺血性脑损伤(hypoxic-ischemic brain injury,HIBI)中的作用。方法...目的:探讨蛋白激酶RNA样ER激酶(protein kinase RNA-like ER kinase,PERK)信号通路介导的线粒体未折叠蛋白反应(mitochondrial unfolded protein response,mtUPR)在缺氧缺血性脑损伤(hypoxic-ischemic brain injury,HIBI)中的作用。方法:将大鼠随机分为假手术(Sham)组和5个HIBI亚组(HIBI后3、6、12、24、48 h)。用于蛋白质印迹检测PERK、转录激活因子4(activating transcription factor 4,ATF4)、热休克蛋白60(heat shock protein 60,HSP60)蛋白的时程表达。将大鼠随机分为Sham组、HIBI组、HIBI+PERK组和HIBI+载体(Vector)组,每组15只。HIBI+PERK组和HIBI+Vector组大鼠在HIBI手术前1 h,将基于腺病毒相关病毒(adeno-associated virus,AAV)的PERK过表达质粒或AAV载体注射到脑室内,用于特异性表达PERK。在HIBI后24 h进行FJC染色分析神经元变性和DHE染色、酶联免疫吸附试验分析氧化应激。将大鼠随机分为Sham组、HIBI组、HIBI+PERK激动剂(CCT020312)组,每组12只。在HIBI手术前1 h,向HIBI+CCT020312组大鼠脑室内注射CCT020312。在HIBI后3周进行开阔场地测试和莫里斯水迷宫测试。结果:与Sham组相比,PERK、ATF4、HSP60在HIBI后3 h开始明显升高,在12 h达到高峰,然后逐渐下降,直到48 h(F=60.23、56.72、74.31,均P<0.001)。与HIBI组相比,HIBI+PERK组神经元变性的数量(100.2±3.1 vs. 582.4±15.7,P<0.001)、活性氧(reactive oxygen species,ROS)(42.4±2.9 vs. 17.7±2.1,P<0.01)、丙二醛(Malondialdehyde,MDA)(0.81±0.06 vs. 0.54±0.04,P<0.001)水平显著降低,和谷胱甘肽过氧化物酶(glutathione peroxidase,GSHPx)(112.4±3.6 vs. 177.5±6.6,P<0.05)、超氧化物歧化酶(superoxide Dismutase,SOD)活性(46.3±1.9 vs. 64.2±2.3,P<0.05)活性明显增加。与Sham组相比,HIBI组大鼠海马组织中PERK(1.00±0.03 vs. 1.66±0.08,P<0.01)、ATF4(1.00±0.04 vs.1.53±0.06,P<0.05)、动力蛋白相关蛋白1(dynamin-related protein 1,Drp1)(1.00±0.02 vs. 1.98±0.07,P<0.01)、HSP60(1.00±0.03 vs. 1.37±0.04,P<0.05)蛋白表达均明显增加(P<0.05)。与HIBI组相比,HIBI+PERK组大鼠海马组织中PERK(1.66±0.08vs. 2.95±0.17,P<0.01)、ATF4(1.53±0.06 vs. 3.42±0.22,P<0.01)、HSP60(1.37±0.04 vs. 2.03±0.09,P<0.05)蛋白表达均明显增加(F=46.72、30.63、20.64,P<0.001),和Drp1(1.98±0.07 vs. 1.04±0.05,P<0.05)蛋白表达明显降低(F=35.72,P<0.001)。HIBI+CCT020312组的平均逃避潜伏期和平台穿越次数均较HIBI组明显增加(F=246.84、113.62,P<0.001)。结论:PERK减轻HIBI模型诱导的氧化应激和神经元凋亡,其机制可能涉及PERK/ATF4信号通路对mtUPR的调节。通过CCT020312给药具有神经保护作用。展开更多
BACKGROUND： Endoplasmic reticulum （ER） stress impairs ER functions and leads to the accumulation of unfolded or misfolded proteins in the ER lumen. ER stress-induced cell death plays an important role in cerebral i...BACKGROUND： Endoplasmic reticulum （ER） stress impairs ER functions and leads to the accumulation of unfolded or misfolded proteins in the ER lumen. ER stress-induced cell death plays an important role in cerebral ischemia. Edaravon （3-methyl-1-phenyl-2-pyrazolin-5-one） is a potent and novel scavenger of free radicals that inhibit delayed neuronal death, as demonstrated by in vitro and animal studies. However, its effect on ER stress and induced neuronal apoptosis in a rat model of brief middle cerebral artery occlusion remains unclear. OBJECTIVE： To explore the effects of edaravone on the expression of ER stress-related factors and neuronal apoptosis, based on the hypothesis that edaravone influences ER stress in a rat model of cerebral ischemia/reperfusion. DESIGN, TIME AND SETTING： A randomized, controlled, animal study was performed at the Laboratory of Department of Neurology, Xiangya Hospital and the Department of Laboratory Animals, Xiangya Medical College, Central South University in China from June 2005 to May 2006. MATERIALS： Edaravone was purchased from Simcere Pharmaceutical Group, China. METHODS： A total of 216 adult, male, Sprague Dawley rats were randomly assigned to sham-surgery, model and edaravone groups, with 72 rats in each group, Brief middle cerebral artery occlusion was established in the model and edaravone groups. In addition, the edaravone group rats were injected with 3 mg/kg edaravone through the tail vein. MAIN OUTCOME MEASURES： RNA-dependent protein kinase-like endoplasmic reticulum eukaryotic translation initiation factor 2a kinase （PERK） and C/EBP homology protein （CHOP） mRNA expression in the ischemic parietal cortex was determined by reverse transcriptionpolymerase chain reaction; phosphorylated PERK and CHOP protein expression was detected by immunohistochemistry; neuronal apoptosis was detected by TdT-mediated-dUTP nick end labeling. RESULTS： Neurological deficit scores were significantly reduced in the edaravone group compared to the model group at 12, 24, and 72 hours following reperfusion （P〈 0.05）. In addition, PERK and CHOP mRNA as well as phosphorylated PERK and CHOP protein expression were significantly reduced in the edaravone group compared to the model group at 1,3, and 6 hours following reperfusion （P 〈 0.05, P 〈 0.01）. CHOP mRNA expression was decreased in the edaravone group compared to the model group at 3, 6, 12, and 24 hours following reperfusion （P〈 0.01）, while CHOP protein expression was less than the model group at 6, 12, and 24 hours following reperfusion （P 〈 0.05）. CONCLUSION： Edaravone treatment resulted in decreased PERK and CHOP expression following ischemia/reperfusion, as well as reduced neuronal apoptosis. Edaravone exhibited a neuroprotective role by inhibiting endoplasmic reticulum stress.展开更多
Cerebral ischemia triggers secondary ischemia/reperfusion injury and endoplasmic reticulum stress initiates cell apoptosis. However, the regulatory mechanism of the signaling pathway remains unclear. We hypothesize th...Cerebral ischemia triggers secondary ischemia/reperfusion injury and endoplasmic reticulum stress initiates cell apoptosis. However, the regulatory mechanism of the signaling pathway remains unclear. We hypothesize that the regulatory mechanisms are mediated by the protein kinase-like endoplasmic reticulum kinase/eukaryotic initiation factor 2α in the endoplasmic reticulum stress signaling pathway. To verify this hypothesis, we occluded the middle cerebral artery in rats to establish focal cerebral ischemia/reperfusion model. Results showed that the expression levels of protein kinase-like endoplasmic reticulum kinase and caspase-3, as well as the phosphorylation of eukaryotic initiation factor 2α, were increased after ischemia/reperfusion. Administration of atorvastatin decreased the expression of protein kinase-like endoplasmic reticulum kinase, caspase-3 and phosphorylated eukaryotic initiation factor 2α, reduced the infarct volume and improved ultrastructure in the rat brain. After salubrinal, the specific inhibitor of phosphorylated eukaryotic initiation factor 2α was given into the rats intragastrically, the expression levels of caspase-3 and phosphorylated eukaryotic initiation factor 2α in the were decreased, a reduction of the infarct volume and less ultrastructural damage were observed than the untreated, ischemic brain. However, salubrinal had no impact on the expression of protein kinase-like endoplasmic reticulum kinase. Experimental findings indicate that atorvastatin inhibits endoplasmic reticulum stress and exerts neuroprotective effects. The underlying mechanisms of attenuating ischemia/reperfusion injury are associated with the protein kinase-like endoplasmic reticulum kinase/eukaryotic initiation factor 2α/caspase-3 pathway.展开更多
Both environmental and genetic factors contribute to the development of diabetes mellitus and although monogenic disorders are rare,they offer unique insights into the fundamental biology underlying the disease.Mutati...Both environmental and genetic factors contribute to the development of diabetes mellitus and although monogenic disorders are rare,they offer unique insights into the fundamental biology underlying the disease.Mutations of the insulin gene or genes involved in the response to protein misfolding cause early onset diabetes.These have revealed an important role for endoplasmic reticulum stress in β-cell survival.This form of cellular stress occurs when secretory proteins fail to fold efficiently.Of all the professional secretory cells we possess,β-cells are the most sensitive to endoplasmic reticulum stress because of the large fluctuations in protein synthesis they face daily.Studies of endoplasmic reticulum stress signaling therefore offer the potential to identify new drug targets to treat diabetes.展开更多
文摘The endoplasmic reticulum is the central organelle within a eukaryotic cell where newly synthesized proteins are processed and properly folded. An excess of unfolded or mis-folded proteins induces ER stress signalling pathways. Usually this means a pro-survival strategy for the cell, whereas under extended stress conditions the ER stress signalling pathways have a pro-apoptotic function. CK2 plays a key role in the regulation of the pro-survival as well as the proapoptotic ER stress signalling by directly modulating the activities of members of the ER stress signalling pathways by phosphorylation, regulating the expression of the key factors of the signalling pathways or binding to regulator proteins. The present review will summarize the state of the art in this new emerging field.
文摘目的:探讨蛋白激酶RNA样ER激酶(protein kinase RNA-like ER kinase,PERK)信号通路介导的线粒体未折叠蛋白反应(mitochondrial unfolded protein response,mtUPR)在缺氧缺血性脑损伤(hypoxic-ischemic brain injury,HIBI)中的作用。方法:将大鼠随机分为假手术(Sham)组和5个HIBI亚组(HIBI后3、6、12、24、48 h)。用于蛋白质印迹检测PERK、转录激活因子4(activating transcription factor 4,ATF4)、热休克蛋白60(heat shock protein 60,HSP60)蛋白的时程表达。将大鼠随机分为Sham组、HIBI组、HIBI+PERK组和HIBI+载体(Vector)组,每组15只。HIBI+PERK组和HIBI+Vector组大鼠在HIBI手术前1 h,将基于腺病毒相关病毒(adeno-associated virus,AAV)的PERK过表达质粒或AAV载体注射到脑室内,用于特异性表达PERK。在HIBI后24 h进行FJC染色分析神经元变性和DHE染色、酶联免疫吸附试验分析氧化应激。将大鼠随机分为Sham组、HIBI组、HIBI+PERK激动剂(CCT020312)组,每组12只。在HIBI手术前1 h,向HIBI+CCT020312组大鼠脑室内注射CCT020312。在HIBI后3周进行开阔场地测试和莫里斯水迷宫测试。结果:与Sham组相比,PERK、ATF4、HSP60在HIBI后3 h开始明显升高,在12 h达到高峰,然后逐渐下降,直到48 h(F=60.23、56.72、74.31,均P<0.001)。与HIBI组相比,HIBI+PERK组神经元变性的数量(100.2±3.1 vs. 582.4±15.7,P<0.001)、活性氧(reactive oxygen species,ROS)(42.4±2.9 vs. 17.7±2.1,P<0.01)、丙二醛(Malondialdehyde,MDA)(0.81±0.06 vs. 0.54±0.04,P<0.001)水平显著降低,和谷胱甘肽过氧化物酶(glutathione peroxidase,GSHPx)(112.4±3.6 vs. 177.5±6.6,P<0.05)、超氧化物歧化酶(superoxide Dismutase,SOD)活性(46.3±1.9 vs. 64.2±2.3,P<0.05)活性明显增加。与Sham组相比,HIBI组大鼠海马组织中PERK(1.00±0.03 vs. 1.66±0.08,P<0.01)、ATF4(1.00±0.04 vs.1.53±0.06,P<0.05)、动力蛋白相关蛋白1(dynamin-related protein 1,Drp1)(1.00±0.02 vs. 1.98±0.07,P<0.01)、HSP60(1.00±0.03 vs. 1.37±0.04,P<0.05)蛋白表达均明显增加(P<0.05)。与HIBI组相比,HIBI+PERK组大鼠海马组织中PERK(1.66±0.08vs. 2.95±0.17,P<0.01)、ATF4(1.53±0.06 vs. 3.42±0.22,P<0.01)、HSP60(1.37±0.04 vs. 2.03±0.09,P<0.05)蛋白表达均明显增加(F=46.72、30.63、20.64,P<0.001),和Drp1(1.98±0.07 vs. 1.04±0.05,P<0.05)蛋白表达明显降低(F=35.72,P<0.001)。HIBI+CCT020312组的平均逃避潜伏期和平台穿越次数均较HIBI组明显增加(F=246.84、113.62,P<0.001)。结论:PERK减轻HIBI模型诱导的氧化应激和神经元凋亡,其机制可能涉及PERK/ATF4信号通路对mtUPR的调节。通过CCT020312给药具有神经保护作用。
文摘BACKGROUND： Endoplasmic reticulum （ER） stress impairs ER functions and leads to the accumulation of unfolded or misfolded proteins in the ER lumen. ER stress-induced cell death plays an important role in cerebral ischemia. Edaravon （3-methyl-1-phenyl-2-pyrazolin-5-one） is a potent and novel scavenger of free radicals that inhibit delayed neuronal death, as demonstrated by in vitro and animal studies. However, its effect on ER stress and induced neuronal apoptosis in a rat model of brief middle cerebral artery occlusion remains unclear. OBJECTIVE： To explore the effects of edaravone on the expression of ER stress-related factors and neuronal apoptosis, based on the hypothesis that edaravone influences ER stress in a rat model of cerebral ischemia/reperfusion. DESIGN, TIME AND SETTING： A randomized, controlled, animal study was performed at the Laboratory of Department of Neurology, Xiangya Hospital and the Department of Laboratory Animals, Xiangya Medical College, Central South University in China from June 2005 to May 2006. MATERIALS： Edaravone was purchased from Simcere Pharmaceutical Group, China. METHODS： A total of 216 adult, male, Sprague Dawley rats were randomly assigned to sham-surgery, model and edaravone groups, with 72 rats in each group, Brief middle cerebral artery occlusion was established in the model and edaravone groups. In addition, the edaravone group rats were injected with 3 mg/kg edaravone through the tail vein. MAIN OUTCOME MEASURES： RNA-dependent protein kinase-like endoplasmic reticulum eukaryotic translation initiation factor 2a kinase （PERK） and C/EBP homology protein （CHOP） mRNA expression in the ischemic parietal cortex was determined by reverse transcriptionpolymerase chain reaction; phosphorylated PERK and CHOP protein expression was detected by immunohistochemistry; neuronal apoptosis was detected by TdT-mediated-dUTP nick end labeling. RESULTS： Neurological deficit scores were significantly reduced in the edaravone group compared to the model group at 12, 24, and 72 hours following reperfusion （P〈 0.05）. In addition, PERK and CHOP mRNA as well as phosphorylated PERK and CHOP protein expression were significantly reduced in the edaravone group compared to the model group at 1,3, and 6 hours following reperfusion （P 〈 0.05, P 〈 0.01）. CHOP mRNA expression was decreased in the edaravone group compared to the model group at 3, 6, 12, and 24 hours following reperfusion （P〈 0.01）, while CHOP protein expression was less than the model group at 6, 12, and 24 hours following reperfusion （P 〈 0.05）. CONCLUSION： Edaravone treatment resulted in decreased PERK and CHOP expression following ischemia/reperfusion, as well as reduced neuronal apoptosis. Edaravone exhibited a neuroprotective role by inhibiting endoplasmic reticulum stress.
文摘Cerebral ischemia triggers secondary ischemia/reperfusion injury and endoplasmic reticulum stress initiates cell apoptosis. However, the regulatory mechanism of the signaling pathway remains unclear. We hypothesize that the regulatory mechanisms are mediated by the protein kinase-like endoplasmic reticulum kinase/eukaryotic initiation factor 2α in the endoplasmic reticulum stress signaling pathway. To verify this hypothesis, we occluded the middle cerebral artery in rats to establish focal cerebral ischemia/reperfusion model. Results showed that the expression levels of protein kinase-like endoplasmic reticulum kinase and caspase-3, as well as the phosphorylation of eukaryotic initiation factor 2α, were increased after ischemia/reperfusion. Administration of atorvastatin decreased the expression of protein kinase-like endoplasmic reticulum kinase, caspase-3 and phosphorylated eukaryotic initiation factor 2α, reduced the infarct volume and improved ultrastructure in the rat brain. After salubrinal, the specific inhibitor of phosphorylated eukaryotic initiation factor 2α was given into the rats intragastrically, the expression levels of caspase-3 and phosphorylated eukaryotic initiation factor 2α in the were decreased, a reduction of the infarct volume and less ultrastructural damage were observed than the untreated, ischemic brain. However, salubrinal had no impact on the expression of protein kinase-like endoplasmic reticulum kinase. Experimental findings indicate that atorvastatin inhibits endoplasmic reticulum stress and exerts neuroprotective effects. The underlying mechanisms of attenuating ischemia/reperfusion injury are associated with the protein kinase-like endoplasmic reticulum kinase/eukaryotic initiation factor 2α/caspase-3 pathway.
基金Supported by a PhD studentship form Diabetes UK (for Thomas SE)
文摘Both environmental and genetic factors contribute to the development of diabetes mellitus and although monogenic disorders are rare,they offer unique insights into the fundamental biology underlying the disease.Mutations of the insulin gene or genes involved in the response to protein misfolding cause early onset diabetes.These have revealed an important role for endoplasmic reticulum stress in β-cell survival.This form of cellular stress occurs when secretory proteins fail to fold efficiently.Of all the professional secretory cells we possess,β-cells are the most sensitive to endoplasmic reticulum stress because of the large fluctuations in protein synthesis they face daily.Studies of endoplasmic reticulum stress signaling therefore offer the potential to identify new drug targets to treat diabetes.
