Objective： To explore the role that ceramide plays in the activation of mitogen-activated protein kinases （MAPKs） during cerebral ischemia and reperfusion. Methods： Rats were subjected to ischemia by the fourvesse...Objective： To explore the role that ceramide plays in the activation of mitogen-activated protein kinases （MAPKs） during cerebral ischemia and reperfusion. Methods： Rats were subjected to ischemia by the fourvessel occlusion （4-VO） method. The sphingomyelinase inhibitor TPCK was administered to the CA1 subregion of the rat hippocampus before inducing ischemia. Western blot was used to examine the activity of extracellular- signal regulated kinase （ERK） and c-Jun N-terminal protein kinase （JNK） using antibodies against ERK, JNK and diphosphorylated ERK and JNK. Results： At lh reperfusion post-ischemia, JNK reached its peak activity while ERK was undergoing a sharp inactivation （P 〈 0.05）. The level of diphosphorylated JNK was significantly reduced but the sharp inactivation of ERK was visibly reversed （P 〈 0.05） by the sphingomyelinase inhibitor. Conclusion： The ceramide signaling pathway is up-regulated through sphingomyelin hydrolysis in brain ischemia, promoting JNK activation and suppressing ERK activation, culminating in the ischemic lesion.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
Objective: This study was designed to explore whether inhibition of the extracellular-regulated kinase (ERK) and phosphatidylinositol-3-kinase (PI3K) signaling pathways can inhibit the growth of xenografts of endometr...Objective: This study was designed to explore whether inhibition of the extracellular-regulated kinase (ERK) and phosphatidylinositol-3-kinase (PI3K) signaling pathways can inhibit the growth of xenografts of endometrial cancer cell lines with different estrogen receptors (ER) profiles in vivo and to provide preliminary laboratory basis for the probability of endometrial adenocarcinoma treatment with blockage of the two pathways, especially to endometrial cancer with low ER status. Methods: Human endometrial cancer Ishikawa bearing ER and HEC-1Awith low ER status cells were subcutaneously injected into BALB/c nude mice to establish endometrial cancer xenograft tumor models. The effects of PI3K/Akt inhibitor LY294002, MAPK/ERK1/2 inhibitor PD-98059 and their combinations on the growth of the xenograft tumors and apoptotic state of Ishikawa and HEC-1Acells were tested in vivo using the inhibitory rate, the terminal deoxynucleotidyl transferase-mediated nick-end labeling assay, H/E-stain. Western blot analysis was used to detect the alterations of activated ERK (P-ERK) and AKT (P-AKT) during this process. Results: LY294002, a PI3K/Akt pathway inhibitor, induced significant suppression in the growth of both Ishikawa and HEC-1Acell xenograft tumors, concomitant with increased apoptosis in xenografts as evidenced by TUNEL. A similar effect was also observed when the MAPK/ERK1/2 signaling pathway was inhibited by PD98059. Concurrent inhibition of the PI3K/Akt and MAPK/ERK1/2 pathways showed enhanced anti-tumor effects in vivo as indicated by increased apoptosis. At the same time, the levels of P-ERK and P-AKT in both xenograft tumors decreased, and their levels in combination group was the lowest. Conclusions: PD98059, LY294002 and their combinations showed remarkable inhibitory effects on xenograft tumors of endometrial carcinoma cell lines with different expression status of ER in vivo through blockage of PI3K/Akt and MAPK/ERK1/2 signaling pathways. This suggests that targeting these pathways may be an effective therapeutic strategy against endometrial carcinomas, especially for ER-negative cancers which show poor response to endocrinal therapy.展开更多
目的:研究支气管哮喘不同时期细胞外信号调节激酶(External signal regulated kinase,ERK)的磷酸化与c-Fos表达,以探讨ERK信号转导途径在支气管哮喘气道重塑中的作用。方法:复制大鼠哮喘模型,随机分为对照组(包括4周、8周及12周对照组)...目的:研究支气管哮喘不同时期细胞外信号调节激酶(External signal regulated kinase,ERK)的磷酸化与c-Fos表达,以探讨ERK信号转导途径在支气管哮喘气道重塑中的作用。方法:复制大鼠哮喘模型,随机分为对照组(包括4周、8周及12周对照组)、哮喘组(包括4周、8周及12周哮喘组),图像分析软件测定支气管壁厚度(Wat)和平滑肌厚度(Wam),免疫组化测定肺组织磷酸化的ERK(Phospho-ERK,P-ERK)与c-Fos表达,免疫印迹法测定磷酸化的ERK水平,直线相关分析法显示Wat和Wam与P-ERK的相关性。结果:各哮喘组Wat和Wam,P-ERK和c-Fos的平均吸光度均显著高于相应对照组(P均<0.01);各哮喘组磷酸化的ERK水平均显著高于相应对照组(其中A12也与C8组比)(P<0.01);Wat、Wam与P-ERK平均吸光度均呈显著正相关性(P<0.01)。结论:ERK磷酸化水平和c-Fos在哮喘大鼠均增加,ERK信号转导途径在支气管哮喘气道重塑中起重要作用。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 grants from the National Natural Science Foundation of China (No.30871200)the Practice and Innovation Training Program for Students in Colleges and Universities of Jiangsu Province (NO.20090370)
文摘Objective： To explore the role that ceramide plays in the activation of mitogen-activated protein kinases （MAPKs） during cerebral ischemia and reperfusion. Methods： Rats were subjected to ischemia by the fourvessel occlusion （4-VO） method. The sphingomyelinase inhibitor TPCK was administered to the CA1 subregion of the rat hippocampus before inducing ischemia. Western blot was used to examine the activity of extracellular- signal regulated kinase （ERK） and c-Jun N-terminal protein kinase （JNK） using antibodies against ERK, JNK and diphosphorylated ERK and JNK. Results： At lh reperfusion post-ischemia, JNK reached its peak activity while ERK was undergoing a sharp inactivation （P 〈 0.05）. The level of diphosphorylated JNK was significantly reduced but the sharp inactivation of ERK was visibly reversed （P 〈 0.05） by the sphingomyelinase inhibitor. Conclusion： The ceramide signaling pathway is up-regulated through sphingomyelin hydrolysis in brain ischemia, promoting JNK activation and suppressing ERK activation, culminating in the ischemic lesion.
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Objective: This study was designed to explore whether inhibition of the extracellular-regulated kinase (ERK) and phosphatidylinositol-3-kinase (PI3K) signaling pathways can inhibit the growth of xenografts of endometrial cancer cell lines with different estrogen receptors (ER) profiles in vivo and to provide preliminary laboratory basis for the probability of endometrial adenocarcinoma treatment with blockage of the two pathways, especially to endometrial cancer with low ER status. Methods: Human endometrial cancer Ishikawa bearing ER and HEC-1Awith low ER status cells were subcutaneously injected into BALB/c nude mice to establish endometrial cancer xenograft tumor models. The effects of PI3K/Akt inhibitor LY294002, MAPK/ERK1/2 inhibitor PD-98059 and their combinations on the growth of the xenograft tumors and apoptotic state of Ishikawa and HEC-1Acells were tested in vivo using the inhibitory rate, the terminal deoxynucleotidyl transferase-mediated nick-end labeling assay, H/E-stain. Western blot analysis was used to detect the alterations of activated ERK (P-ERK) and AKT (P-AKT) during this process. Results: LY294002, a PI3K/Akt pathway inhibitor, induced significant suppression in the growth of both Ishikawa and HEC-1Acell xenograft tumors, concomitant with increased apoptosis in xenografts as evidenced by TUNEL. A similar effect was also observed when the MAPK/ERK1/2 signaling pathway was inhibited by PD98059. Concurrent inhibition of the PI3K/Akt and MAPK/ERK1/2 pathways showed enhanced anti-tumor effects in vivo as indicated by increased apoptosis. At the same time, the levels of P-ERK and P-AKT in both xenograft tumors decreased, and their levels in combination group was the lowest. Conclusions: PD98059, LY294002 and their combinations showed remarkable inhibitory effects on xenograft tumors of endometrial carcinoma cell lines with different expression status of ER in vivo through blockage of PI3K/Akt and MAPK/ERK1/2 signaling pathways. This suggests that targeting these pathways may be an effective therapeutic strategy against endometrial carcinomas, especially for ER-negative cancers which show poor response to endocrinal therapy.
文摘目的:研究支气管哮喘不同时期细胞外信号调节激酶(External signal regulated kinase,ERK)的磷酸化与c-Fos表达,以探讨ERK信号转导途径在支气管哮喘气道重塑中的作用。方法:复制大鼠哮喘模型,随机分为对照组(包括4周、8周及12周对照组)、哮喘组(包括4周、8周及12周哮喘组),图像分析软件测定支气管壁厚度(Wat)和平滑肌厚度(Wam),免疫组化测定肺组织磷酸化的ERK(Phospho-ERK,P-ERK)与c-Fos表达,免疫印迹法测定磷酸化的ERK水平,直线相关分析法显示Wat和Wam与P-ERK的相关性。结果:各哮喘组Wat和Wam,P-ERK和c-Fos的平均吸光度均显著高于相应对照组(P均<0.01);各哮喘组磷酸化的ERK水平均显著高于相应对照组(其中A12也与C8组比)(P<0.01);Wat、Wam与P-ERK平均吸光度均呈显著正相关性(P<0.01)。结论:ERK磷酸化水平和c-Fos在哮喘大鼠均增加,ERK信号转导途径在支气管哮喘气道重塑中起重要作用。
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。
