The phosphatidylinositol-3 kinase （PI3K）/Akt pathway and brain-derived neurotrophic factor （BDNF） are involved in neurological functional recovery following cerebral ischemia. Therefore, we hypothesized that mecha...The phosphatidylinositol-3 kinase （PI3K）/Akt pathway and brain-derived neurotrophic factor （BDNF） are involved in neurological functional recovery following cerebral ischemia. Therefore, we hypothesized that mechanisms of neuroprotection by transplantation of neural stem cells （NSCs） on cerebral ischemia contributed to activation of the PI3K/Akt pathway and enhanced BDNF expression. In the present study, Wortmannin （a specific, covalent inhibitor of PI3K） was administered adjacent to ischemic hippocampus by stereotactic transplantation to further confirm the neuroprotective mechanisms of NSC transplantation following cerebral ischemia. Results showed that focal infarct volume was significantly smaller in the NSCs group, but the neurological behavior score in the NSC group was significantly greater than the middle cerebral artery occlusion model group, Wortmannin treatment group, and NSCs ＋ Wortmannin treatment group. Protein expression of BDNF was significantly greater in the NSC group compared with the Wortmannin treatment group and NSCs ＋ Wortmannin treatment group. These results suggest that the neuroprotective role of NSC transplantation in the cerebral ischemia activated the PI3K/Akt pathway and upregulated BDNF expression in lesioned brains.展开更多
Brain-derived neurotrophic factor(BDNF)has robust effects on synaptogenesis,neuronal differentiation and synaptic transmission and plasticity.The maturation of BDNF is a complex process.Proprotein convertase 1/3(PC1/3...Brain-derived neurotrophic factor(BDNF)has robust effects on synaptogenesis,neuronal differentiation and synaptic transmission and plasticity.The maturation of BDNF is a complex process.Proprotein convertase 1/3(PC1/3)has a key role in the cleavage of protein precursors that are directed to regulated secretory pathways;however,it is not clear whether PC1/3 mediates the change in BDNF levels caused by ischemia.To clarify the role of PC1/3 in BDNF maturation in ischemic cortical neurons,primary cortical neurons from fetal rats were cultured in a humidified environment of 95%N_2 and 5%CO_2 in a glucose-free Dulbecco's modified Eagle's medium at 37℃for3 hours.Enzyme-linked immunosorbent assays and western blotting showed that after oxygen-glucose deprivation,the secreted and intracellular levels of BDNF were significantly reduced and the intracellular level of PC1/3 was decreased.Transient transfection of cortical neurons with a PC1/3 overexpression plasmid followed by oxygen-glucose deprivation resulted in increased PC1/3 levels and increased BDNF levels.When levels of the BDNF precursor protein were reduced,the concentration of BDNF in the culture medium was increased.These results indicate that PC 1/3 cleavage of BDNF is critical for the conversion of pro-BDNF in rat cortical neurons during ischemia.The study was approved by the Animal Ethics Committee of Wuhan University School of Basic Medical Sciences.展开更多
Pitx3 is strongly associated with the phenotype, differentiation, and survival of dopaminergic neurons. The relationship between Pitx3 and glial cell line-derived neurotrophic factor（GDNF） in dopaminergic neurons re...Pitx3 is strongly associated with the phenotype, differentiation, and survival of dopaminergic neurons. The relationship between Pitx3 and glial cell line-derived neurotrophic factor（GDNF） in dopaminergic neurons remains poorly understood. The present investigation sought to construct and screen a lentivirus expression plasmid carrying a rat Pitx3 short hairpin（sh）RNA and to assess the impact of Pitx3 gene knockdown on GDNF transcriptional activity in MES23.5 dopaminergic neurons. Three pairs of interference sequences were designed and separately ligated into GV102 expression vectors. These recombinant plasmids were transfected into MES23.5 cells and western blot assays were performed to detect Pitx3 protein expression. Finally, the most effective Pitx3 sh RNA and a dual-luciferase reporter gene plasmid carrying the GDNF promoter region（GDNF-luciferase） were cotransfected into MES23.5 cells. Sequencing showed that the synthesized sequences were identical to the three Pitx3 interference sequences. Inverted fluorescence microscopy revealed that the lentivirus expression plasmids carrying Pitx3-sh RNA had 40-50% transfection efficiency. Western blot assay confirmed that the corresponding Pitx3 of the third knockdown sequence had the lowest expression level. Dual-luciferase reporter gene results showed that the GDNF transcriptional activity in dopaminergic cells cotransfected with both plasmids was decreased compared with those transfected with GDNF-luciferase alone. Together, the results showed that the designed Pitx3-sh RNA interference sequence decreased Pitx3 protein expression, which decreased GDNF transcriptional activity.展开更多
目的:利用羟基磷灰石纳米颗粒(hydroxyapatite nanoparticle,HAT)携带构建的神经营养因子-3(neurotrophic factor-3,NT-3)-绿色荧光蛋白基因(enhancement type Green fluorescent protein C2,pEGFPC2),通过耳蜗灌注方法转染兴奋毒性损...目的:利用羟基磷灰石纳米颗粒(hydroxyapatite nanoparticle,HAT)携带构建的神经营养因子-3(neurotrophic factor-3,NT-3)-绿色荧光蛋白基因(enhancement type Green fluorescent protein C2,pEGFPC2),通过耳蜗灌注方法转染兴奋毒性损伤后的豚鼠耳蜗螺旋神经节细胞(spinal ganglion cells,SGCs),观察pEGFPC2-NT3的表达及其对耳蜗螺旋神经节细胞的保护作用。方法:构建携带绿色荧光蛋白报告基因的重组质粒pEGFPC2-NT3。通过耳蜗灌注海人酸(kainic acid,KA)建立豚鼠耳蜗兴奋性损伤模型,在给KA1周后利用HAT携带重组质粒进行耳蜗灌注以转染耳蜗螺旋神经节细胞,免疫组化法观察转染后1周NT-3的表达及4周后电镜下螺旋神经节细胞形态学变化,同时观察对听觉脑干诱发电位(auditory brain-stem response,ABR)的影响。结果:成功构建豚鼠耳蜗兴奋损伤模型。灌注重组质粒后1周免疫组化法观察到螺旋神经节细胞胞浆内NT-3蛋白表达。4周后电镜下螺旋神经节细胞形态学损害减轻,ABR检测听功能较兴奋毒性损害后有恢复。结论:在豚鼠耳蜗灌注KA造成耳蜗兴奋性损伤后第7天,经耳蜗鼓阶转染羟基磷灰石纳米颗粒介导的NT-3基因仍可减轻KA对耳蜗螺旋神经节细胞的兴奋性毒性损伤。展开更多
文摘The phosphatidylinositol-3 kinase （PI3K）/Akt pathway and brain-derived neurotrophic factor （BDNF） are involved in neurological functional recovery following cerebral ischemia. Therefore, we hypothesized that mechanisms of neuroprotection by transplantation of neural stem cells （NSCs） on cerebral ischemia contributed to activation of the PI3K/Akt pathway and enhanced BDNF expression. In the present study, Wortmannin （a specific, covalent inhibitor of PI3K） was administered adjacent to ischemic hippocampus by stereotactic transplantation to further confirm the neuroprotective mechanisms of NSC transplantation following cerebral ischemia. Results showed that focal infarct volume was significantly smaller in the NSCs group, but the neurological behavior score in the NSC group was significantly greater than the middle cerebral artery occlusion model group, Wortmannin treatment group, and NSCs ＋ Wortmannin treatment group. Protein expression of BDNF was significantly greater in the NSC group compared with the Wortmannin treatment group and NSCs ＋ Wortmannin treatment group. These results suggest that the neuroprotective role of NSC transplantation in the cerebral ischemia activated the PI3K/Akt pathway and upregulated BDNF expression in lesioned brains.
基金supported by the National Nature Science Foundation of China,No.81501053(to YC)
文摘Brain-derived neurotrophic factor(BDNF)has robust effects on synaptogenesis,neuronal differentiation and synaptic transmission and plasticity.The maturation of BDNF is a complex process.Proprotein convertase 1/3(PC1/3)has a key role in the cleavage of protein precursors that are directed to regulated secretory pathways;however,it is not clear whether PC1/3 mediates the change in BDNF levels caused by ischemia.To clarify the role of PC1/3 in BDNF maturation in ischemic cortical neurons,primary cortical neurons from fetal rats were cultured in a humidified environment of 95%N_2 and 5%CO_2 in a glucose-free Dulbecco's modified Eagle's medium at 37℃for3 hours.Enzyme-linked immunosorbent assays and western blotting showed that after oxygen-glucose deprivation,the secreted and intracellular levels of BDNF were significantly reduced and the intracellular level of PC1/3 was decreased.Transient transfection of cortical neurons with a PC1/3 overexpression plasmid followed by oxygen-glucose deprivation resulted in increased PC1/3 levels and increased BDNF levels.When levels of the BDNF precursor protein were reduced,the concentration of BDNF in the culture medium was increased.These results indicate that PC 1/3 cleavage of BDNF is critical for the conversion of pro-BDNF in rat cortical neurons during ischemia.The study was approved by the Animal Ethics Committee of Wuhan University School of Basic Medical Sciences.
基金supported by the National Natural Science Foundation of China,No.81372698
文摘Pitx3 is strongly associated with the phenotype, differentiation, and survival of dopaminergic neurons. The relationship between Pitx3 and glial cell line-derived neurotrophic factor（GDNF） in dopaminergic neurons remains poorly understood. The present investigation sought to construct and screen a lentivirus expression plasmid carrying a rat Pitx3 short hairpin（sh）RNA and to assess the impact of Pitx3 gene knockdown on GDNF transcriptional activity in MES23.5 dopaminergic neurons. Three pairs of interference sequences were designed and separately ligated into GV102 expression vectors. These recombinant plasmids were transfected into MES23.5 cells and western blot assays were performed to detect Pitx3 protein expression. Finally, the most effective Pitx3 sh RNA and a dual-luciferase reporter gene plasmid carrying the GDNF promoter region（GDNF-luciferase） were cotransfected into MES23.5 cells. Sequencing showed that the synthesized sequences were identical to the three Pitx3 interference sequences. Inverted fluorescence microscopy revealed that the lentivirus expression plasmids carrying Pitx3-sh RNA had 40-50% transfection efficiency. Western blot assay confirmed that the corresponding Pitx3 of the third knockdown sequence had the lowest expression level. Dual-luciferase reporter gene results showed that the GDNF transcriptional activity in dopaminergic cells cotransfected with both plasmids was decreased compared with those transfected with GDNF-luciferase alone. Together, the results showed that the designed Pitx3-sh RNA interference sequence decreased Pitx3 protein expression, which decreased GDNF transcriptional activity.
文摘目的:利用羟基磷灰石纳米颗粒(hydroxyapatite nanoparticle,HAT)携带构建的神经营养因子-3(neurotrophic factor-3,NT-3)-绿色荧光蛋白基因(enhancement type Green fluorescent protein C2,pEGFPC2),通过耳蜗灌注方法转染兴奋毒性损伤后的豚鼠耳蜗螺旋神经节细胞(spinal ganglion cells,SGCs),观察pEGFPC2-NT3的表达及其对耳蜗螺旋神经节细胞的保护作用。方法:构建携带绿色荧光蛋白报告基因的重组质粒pEGFPC2-NT3。通过耳蜗灌注海人酸(kainic acid,KA)建立豚鼠耳蜗兴奋性损伤模型,在给KA1周后利用HAT携带重组质粒进行耳蜗灌注以转染耳蜗螺旋神经节细胞,免疫组化法观察转染后1周NT-3的表达及4周后电镜下螺旋神经节细胞形态学变化,同时观察对听觉脑干诱发电位(auditory brain-stem response,ABR)的影响。结果:成功构建豚鼠耳蜗兴奋损伤模型。灌注重组质粒后1周免疫组化法观察到螺旋神经节细胞胞浆内NT-3蛋白表达。4周后电镜下螺旋神经节细胞形态学损害减轻,ABR检测听功能较兴奋毒性损害后有恢复。结论:在豚鼠耳蜗灌注KA造成耳蜗兴奋性损伤后第7天,经耳蜗鼓阶转染羟基磷灰石纳米颗粒介导的NT-3基因仍可减轻KA对耳蜗螺旋神经节细胞的兴奋性毒性损伤。
