Activation of extracellular signal-regulated kinase 1/2 has been demonstrated in acute brain ischemia. We hypothesized that activated extracellular signal-regulated kinase 1/2 can protect hippocampal neurons from inju...Activation of extracellular signal-regulated kinase 1/2 has been demonstrated in acute brain ischemia. We hypothesized that activated extracellular signal-regulated kinase 1/2 can protect hippocampal neurons from injury in a diabetic model after cerebral ischemia/reperfusion. In this study, transient whole-brain ischemia was induced by four-vessel occlusion in normal and diabetic rats, and extracellular signal-regulated kinase 1/2 inhibitor （U0126） was administered into diabetic rats 30 minutes before ischemia as a pretreatment. Results showed that the number of surviving neurons in the hippocampal CA1 region was reduced, extracellular signal-regulated kinase 1/2 phosphorylation and KuT0 activity were decreased, and pro-apoptotic Bax expression was upregulated after intervention using U0126. These findings demonstrate that inhibition of extracellular signal-regulated kinase 1/2 activity aggravated neuronal loss in the hippocampus in a diabetic rat after cerebral ischemia/reperfusion, further decreased DNA repairing ability and ac- celerated apoptosis in hippocampal neurons. Extracellular signal-regulated kinase 1/2 activation plays a neuroprotective role in hippocampal neurons in a diabetic rat after cerebral ischemia/ reperfusion.展开更多
The mitogen activated protein kinases-extracellular signal regulated kinases (MAPK-ERK) pathway is involved in regulation of multiple cellular processes including the cell cycle. In the present study using a Huh7 cell...The mitogen activated protein kinases-extracellular signal regulated kinases (MAPK-ERK) pathway is involved in regulation of multiple cellular processes including the cell cycle. In the present study using a Huh7 cell line Con1 with an HCV replicon, we have shown that the MAPK-ERK pathway plays a significant role in the modulation of HCV replication and protein expression and might influence IFN-α signalling. Epithelial growth factor (EGF) was able to stimulate ERK activation and decreased HCV RNA load while a MAPK-ERK pathway inhibitor U0126 led to an elevated HCV RNA load and higher NS5A protein amounts in Con1 cells. It could be further demonstrated that the inhibition of the MAPK-ERK pathway facilitated the translation directed by the HCV internal ribosome entry site. Consistently, a U0126 treatment enhanced activity of the HCV reporter replicon in transient transfection assays. Thus, the MAPK-ERK pathway plays an important role in the regulation of HCV gene expression and replication. In addition, cyclin-dependent kinases (CDKs) downstream of ERK may also be involved in the modulation of HCV replication since roscovitine, an inhibitor of CDKs had a similar effect to that of U0126. Modulation of the cell cycle progression by cell cycle inhibitor or RNAi resulted consistently in changes of HCV RNA levels. Further, the replication of HCV replicon in Con1 cells was inhibited by IFN-α. The inhibitory effect of IFN-α could be partly reversed by pre-incubation of Con-1 cells with inhibitors of the MAPK-ERK pathway and CDKs. It could be shown that the MAPK-ERK inhibitors are able to partially modulate the expression of interferon-stimulated genes.展开更多
目的探索Jurkat T细胞中胞外调节蛋白激酶(extracellular regulated protein kinases,ERK)活性动力学以及基质刚度对ERK活性的影响。方法利用荧光共振能量转移(fluorescence resonance energy transfer,FRET)技术实时观测Jurkat细胞中ER...目的探索Jurkat T细胞中胞外调节蛋白激酶(extracellular regulated protein kinases,ERK)活性动力学以及基质刚度对ERK活性的影响。方法利用荧光共振能量转移(fluorescence resonance energy transfer,FRET)技术实时观测Jurkat细胞中ERK活性的变化,或细胞处于I型胶原基质胶中检测其影响。结果部分Jurkat细胞中存在ERK活性脉冲现象,频率约为3次/h,FRET振幅变化约为20%。在抗体激活T细胞抗原受体(T-cell receptor,TCR)的条件下,ERK脉冲依然存在,频率和振幅无显著变化。当细胞处于I型胶原水凝胶中,随着胶基质刚度增加,脉冲频率有所下调。结论Jurkat T细胞中存在自发的ERK活性脉冲现象,初步实验显示其频率受基质刚度影响。而该信号波动的生理意义和分子机制仍有待探索。展开更多
目的：探讨细胞外信号调节蛋白激酶（ERK）通路在慢性哮喘大鼠气道平滑肌细胞（ASMC）凋亡中的作用及其机制。方法：30只Wistar大鼠分为正常对照组（A组）和慢性哮喘组（B组），用原位末端标记法和Annexin—V FIT CPI双染色法观察ASMC...目的：探讨细胞外信号调节蛋白激酶（ERK）通路在慢性哮喘大鼠气道平滑肌细胞（ASMC）凋亡中的作用及其机制。方法：30只Wistar大鼠分为正常对照组（A组）和慢性哮喘组（B组），用原位末端标记法和Annexin—V FIT CPI双染色法观察ASMC凋亡，免疫组织化学法检测bcl-2和bax的表达，Western blot检测caspase-3蛋白的表达，并用ERK激动剂表皮生长因子（EGF）和抑制剂PD98059干预两组ASMC，观察上述指标的变化。结果：与正常对照组ASMC比较，慢性哮喘组ASMC凋亡指数、早期凋亡细胞百分率明显下降。经PD98059干预之后，慢性哮喘组ASMC的凋亡指数与早期凋亡细胞百分率、bax蛋白表达量和caspase-3蛋白含量明显增高，bcl-2蛋白表达量明显降低。经EGF干预之后，慢性哮喘组ASMC凋亡指数与早期凋亡细胞百分率进一步下降，而这一作用可以被PD98059所抑制。结论：慢性哮喘组大鼠ASMC内源性增殖活性增加的同时，伴有凋亡活性下降。ERK1／2参与慢性哮喘ASMC凋亡调控，其机制与bcl-2家族和caspace-3有关。展开更多
基金supported by the Hebei Province Natural Science Program,No.H2012401007a grant from the foundation Key Project of Hebei Province Education Ministry,No.ZD2010106
文摘Activation of extracellular signal-regulated kinase 1/2 has been demonstrated in acute brain ischemia. We hypothesized that activated extracellular signal-regulated kinase 1/2 can protect hippocampal neurons from injury in a diabetic model after cerebral ischemia/reperfusion. In this study, transient whole-brain ischemia was induced by four-vessel occlusion in normal and diabetic rats, and extracellular signal-regulated kinase 1/2 inhibitor （U0126） was administered into diabetic rats 30 minutes before ischemia as a pretreatment. Results showed that the number of surviving neurons in the hippocampal CA1 region was reduced, extracellular signal-regulated kinase 1/2 phosphorylation and KuT0 activity were decreased, and pro-apoptotic Bax expression was upregulated after intervention using U0126. These findings demonstrate that inhibition of extracellular signal-regulated kinase 1/2 activity aggravated neuronal loss in the hippocampus in a diabetic rat after cerebral ischemia/reperfusion, further decreased DNA repairing ability and ac- celerated apoptosis in hippocampal neurons. Extracellular signal-regulated kinase 1/2 activation plays a neuroprotective role in hippocampal neurons in a diabetic rat after cerebral ischemia/ reperfusion.
基金supported by a joint grant of Chinese Academy of Science and Deutsche Akademische Austausch Dienstthe National Basic Research Priorities Program ofChina(2009CB522501,2005CB522901,2007CB512901)
文摘The mitogen activated protein kinases-extracellular signal regulated kinases (MAPK-ERK) pathway is involved in regulation of multiple cellular processes including the cell cycle. In the present study using a Huh7 cell line Con1 with an HCV replicon, we have shown that the MAPK-ERK pathway plays a significant role in the modulation of HCV replication and protein expression and might influence IFN-α signalling. Epithelial growth factor (EGF) was able to stimulate ERK activation and decreased HCV RNA load while a MAPK-ERK pathway inhibitor U0126 led to an elevated HCV RNA load and higher NS5A protein amounts in Con1 cells. It could be further demonstrated that the inhibition of the MAPK-ERK pathway facilitated the translation directed by the HCV internal ribosome entry site. Consistently, a U0126 treatment enhanced activity of the HCV reporter replicon in transient transfection assays. Thus, the MAPK-ERK pathway plays an important role in the regulation of HCV gene expression and replication. In addition, cyclin-dependent kinases (CDKs) downstream of ERK may also be involved in the modulation of HCV replication since roscovitine, an inhibitor of CDKs had a similar effect to that of U0126. Modulation of the cell cycle progression by cell cycle inhibitor or RNAi resulted consistently in changes of HCV RNA levels. Further, the replication of HCV replicon in Con1 cells was inhibited by IFN-α. The inhibitory effect of IFN-α could be partly reversed by pre-incubation of Con-1 cells with inhibitors of the MAPK-ERK pathway and CDKs. It could be shown that the MAPK-ERK inhibitors are able to partially modulate the expression of interferon-stimulated genes.
文摘目的探索Jurkat T细胞中胞外调节蛋白激酶(extracellular regulated protein kinases,ERK)活性动力学以及基质刚度对ERK活性的影响。方法利用荧光共振能量转移(fluorescence resonance energy transfer,FRET)技术实时观测Jurkat细胞中ERK活性的变化,或细胞处于I型胶原基质胶中检测其影响。结果部分Jurkat细胞中存在ERK活性脉冲现象,频率约为3次/h,FRET振幅变化约为20%。在抗体激活T细胞抗原受体(T-cell receptor,TCR)的条件下,ERK脉冲依然存在,频率和振幅无显著变化。当细胞处于I型胶原水凝胶中,随着胶基质刚度增加,脉冲频率有所下调。结论Jurkat T细胞中存在自发的ERK活性脉冲现象,初步实验显示其频率受基质刚度影响。而该信号波动的生理意义和分子机制仍有待探索。
文摘目的：探讨细胞外信号调节蛋白激酶（ERK）通路在慢性哮喘大鼠气道平滑肌细胞（ASMC）凋亡中的作用及其机制。方法：30只Wistar大鼠分为正常对照组（A组）和慢性哮喘组（B组），用原位末端标记法和Annexin—V FIT CPI双染色法观察ASMC凋亡，免疫组织化学法检测bcl-2和bax的表达，Western blot检测caspase-3蛋白的表达，并用ERK激动剂表皮生长因子（EGF）和抑制剂PD98059干预两组ASMC，观察上述指标的变化。结果：与正常对照组ASMC比较，慢性哮喘组ASMC凋亡指数、早期凋亡细胞百分率明显下降。经PD98059干预之后，慢性哮喘组ASMC的凋亡指数与早期凋亡细胞百分率、bax蛋白表达量和caspase-3蛋白含量明显增高，bcl-2蛋白表达量明显降低。经EGF干预之后，慢性哮喘组ASMC凋亡指数与早期凋亡细胞百分率进一步下降，而这一作用可以被PD98059所抑制。结论：慢性哮喘组大鼠ASMC内源性增殖活性增加的同时，伴有凋亡活性下降。ERK1／2参与慢性哮喘ASMC凋亡调控，其机制与bcl-2家族和caspace-3有关。
