目的研究葛根素对氧糖剥夺(oxygen and glucose deprivation,OGD)血管性痴呆细胞模型细胞黏附分子(CaM)、钙调蛋白激酶Ⅱ(CaMKⅡ)、脑源性神经营养因子(BDNF)及Akt表达的影响。方法选取生长良好的PC12细胞传代、分化,行OGD准备血管性痴...目的研究葛根素对氧糖剥夺(oxygen and glucose deprivation,OGD)血管性痴呆细胞模型细胞黏附分子(CaM)、钙调蛋白激酶Ⅱ(CaMKⅡ)、脑源性神经营养因子(BDNF)及Akt表达的影响。方法选取生长良好的PC12细胞传代、分化,行OGD准备血管性痴呆细胞模型,随机分为对照组、模型组及低、中、高剂量葛根素组。MTT法测定细胞存活率并确定合适的葛根素干预浓度及OGD处理时间;检测乳酸脱氢酶(LDH)释放量评定细胞损伤程度,鉴定细胞模型;Western blot检测CaM、CaMKⅡ、MECP2、BDNF及Akt蛋白的表达水平。结果 PC12细胞存活率随OGD时间延长而逐渐降低,呈时间依赖性;PC12细胞存活率随葛根素浓度增加而逐渐升高,呈浓度依赖性。葛根素有效干预浓度为0.1～10μmol/L;OGD最佳处理时间为6h。与对照组相比,模型组LDH释放量明显增高(P<0.05);葛根素干预组LDH释放量随葛根素浓度增加而减少(P<0.05)。模型组CaM蛋白表达明显升高,BDNF表达量明显减少(P<0.05),MECP2表达及CaMKⅡ、Akt蛋白磷酸化水平均未见明显变化(P>0.05)。葛根素干预可下调CaM蛋白水平,提高MECP2、BDNF的表达及CaMKⅡ磷酸化水平,中、高剂量葛根素组亦能升高Akt蛋白磷酸化水平(P<0.05)。结论葛根素可能通过提高Ca2+-CaM复合物介导CaMKⅡ自身磷酸化水平,诱导MECP2磷酸化,上调BDNF的表达,激活下游PI3K-Akt通路,抑制凋亡基因及蛋白表达,发挥神经保护作用。展开更多
目的构建稳定的α7 n AChR沉默的神经母细胞瘤细胞(SH-SY5Y)细胞,研究α7神经型尼古丁受体(n AChR)基因沉默对钙调蛋白(Ca M)、钙调素依赖性蛋白激酶Ⅱ(Ca MKⅡ)水平的影响,了解α7 n AChR神经保护作用及其与阿尔茨海默病(AD)发病机制...目的构建稳定的α7 n AChR沉默的神经母细胞瘤细胞(SH-SY5Y)细胞,研究α7神经型尼古丁受体(n AChR)基因沉默对钙调蛋白(Ca M)、钙调素依赖性蛋白激酶Ⅱ(Ca MKⅡ)水平的影响,了解α7 n AChR神经保护作用及其与阿尔茨海默病(AD)发病机制的关系。方法将α7 n AChR shRNA重组质转染到SH-SY5Y,用含嘌呤霉素的培养液筛选,挑选阳性克隆后采用实时荧光定量PCR和蛋白质印迹方法(Western-blot)检测细胞中α7n AChR mRNA及蛋白表达水平的变化;Western-blot方法测定Ca M、Ca MKⅡ蛋白表达水平。结果获得稳定转染α7 n AChR shRNA重组质粒的细胞克隆株,与对照组相比,α7 n AChR mRNA及蛋白表达量分别减少了95%和80%。Ca M、Ca MKⅡ蛋白表达量分别减少了48.5%和35%。结论成功构建了α7 n AChR mRNA沉默的SH-SY5Y细胞细胞株,α7 n AChR沉默降低了Ca M、Ca MKⅡ的蛋白水平,可能影响信号通路转导,这可能与阿尔茨海默病(AD)的发病有一定的关系。展开更多
OBJECTIVE Alzheimer disease(AD) is the most common type of dementia and is featured by the accumulation of β-amyloid peptide(Aβ) in the brain. The Alpha 7 nicotinic acetylcholine receptor family(α7 nAChR) was widel...OBJECTIVE Alzheimer disease(AD) is the most common type of dementia and is featured by the accumulation of β-amyloid peptide(Aβ) in the brain. The Alpha 7 nicotinic acetylcholine receptor family(α7 nAChR) was widely considered to interact with that Aβ, mediate neuroprotection and improve cognitive performance. However, the mechanisms underlying these interactions remain elusive. The present study aimed to determine how this interaction contribute to AD pathology. METHODS In vitro model of AD(primary culture of mice hippocampus treated with Aβ) and in vivo, a mouse model of AD(APPswe/PSEN1 d E9 double transgenic mice, APP/PS1_DT mice) were used to study to the possible inter-action of α7 nAChR and Aβ in the pathogenesis of AD. In vitro experiments, the primary hippocampal neurons cell was exposed to Aβ1-42 peptides in combination with PNU. In vivo experiments, different drugs/operations was applied to APP/PS1_DT mice for setting up of the following groups: WP group, wild-type C57 mice treated with PNU(α7 nAChR specific agonist);AP group, APP/PS1_DT mice treated with PNU;APP/PS1 group, the APP/PS1_DT mice injected intraperitoneally with the same amount of normal saline for 5 d;Control group, wild-type C57 mice injected intraperitoneally with the same amount of normal saline for 5 d. A transmission electron microscope was used to observed the synaptic morphological changes of hippocampal neurons. Reverse transcription quantitative PCR(RT-q PCR) and Western blot analysis were used to detect the expression levels of synaptic-associated proteins(SYN, SNAP25 etc). The learning and memory abilities of mice were detected by Morris water maze. RESULTS In vitro, it was found that α7 nAChR acts as an anti-Aβ-induced synaptic injury to nerve cell by increased the expression of synaptic-associated proteins and attenuated apoptosis induced by Aβ oligomers. In vivo, α7 nAChR attenuated synaptic loss induced by Aβ1-42, reduced the deposition of Aβ1-42 in the hippocampus and maintained the integrity of synaptic structures in the hippocampus. Furthermore, in the Morris water maze test, α7 nAChR improved the learning and memory ability of the APP/PS1_DT mice. CONCLUSION Theα7 nAChR attenuate the toxic effect of Aβ in vivo and in vitro, eg reduced the deposition of Aβ in the hippocampus,prevented the synaptic loss, partially restored the expression levels of synaptic-associated proteins, and improved the learning and memory abilities of APP/PS1_DT mice. Our results also suggested that the α7 nAChR interacted with Aβby mediated by Ca M-Ca MKⅡ-CREB signalling pathway, which was imbalanced by deposition of Aβ.展开更多
文摘目的构建稳定的α7 n AChR沉默的神经母细胞瘤细胞(SH-SY5Y)细胞,研究α7神经型尼古丁受体(n AChR)基因沉默对钙调蛋白(Ca M)、钙调素依赖性蛋白激酶Ⅱ(Ca MKⅡ)水平的影响,了解α7 n AChR神经保护作用及其与阿尔茨海默病(AD)发病机制的关系。方法将α7 n AChR shRNA重组质转染到SH-SY5Y,用含嘌呤霉素的培养液筛选,挑选阳性克隆后采用实时荧光定量PCR和蛋白质印迹方法(Western-blot)检测细胞中α7n AChR mRNA及蛋白表达水平的变化;Western-blot方法测定Ca M、Ca MKⅡ蛋白表达水平。结果获得稳定转染α7 n AChR shRNA重组质粒的细胞克隆株,与对照组相比,α7 n AChR mRNA及蛋白表达量分别减少了95%和80%。Ca M、Ca MKⅡ蛋白表达量分别减少了48.5%和35%。结论成功构建了α7 n AChR mRNA沉默的SH-SY5Y细胞细胞株,α7 n AChR沉默降低了Ca M、Ca MKⅡ的蛋白水平,可能影响信号通路转导,这可能与阿尔茨海默病(AD)的发病有一定的关系。
文摘OBJECTIVE Alzheimer disease(AD) is the most common type of dementia and is featured by the accumulation of β-amyloid peptide(Aβ) in the brain. The Alpha 7 nicotinic acetylcholine receptor family(α7 nAChR) was widely considered to interact with that Aβ, mediate neuroprotection and improve cognitive performance. However, the mechanisms underlying these interactions remain elusive. The present study aimed to determine how this interaction contribute to AD pathology. METHODS In vitro model of AD(primary culture of mice hippocampus treated with Aβ) and in vivo, a mouse model of AD(APPswe/PSEN1 d E9 double transgenic mice, APP/PS1_DT mice) were used to study to the possible inter-action of α7 nAChR and Aβ in the pathogenesis of AD. In vitro experiments, the primary hippocampal neurons cell was exposed to Aβ1-42 peptides in combination with PNU. In vivo experiments, different drugs/operations was applied to APP/PS1_DT mice for setting up of the following groups: WP group, wild-type C57 mice treated with PNU(α7 nAChR specific agonist);AP group, APP/PS1_DT mice treated with PNU;APP/PS1 group, the APP/PS1_DT mice injected intraperitoneally with the same amount of normal saline for 5 d;Control group, wild-type C57 mice injected intraperitoneally with the same amount of normal saline for 5 d. A transmission electron microscope was used to observed the synaptic morphological changes of hippocampal neurons. Reverse transcription quantitative PCR(RT-q PCR) and Western blot analysis were used to detect the expression levels of synaptic-associated proteins(SYN, SNAP25 etc). The learning and memory abilities of mice were detected by Morris water maze. RESULTS In vitro, it was found that α7 nAChR acts as an anti-Aβ-induced synaptic injury to nerve cell by increased the expression of synaptic-associated proteins and attenuated apoptosis induced by Aβ oligomers. In vivo, α7 nAChR attenuated synaptic loss induced by Aβ1-42, reduced the deposition of Aβ1-42 in the hippocampus and maintained the integrity of synaptic structures in the hippocampus. Furthermore, in the Morris water maze test, α7 nAChR improved the learning and memory ability of the APP/PS1_DT mice. CONCLUSION Theα7 nAChR attenuate the toxic effect of Aβ in vivo and in vitro, eg reduced the deposition of Aβ in the hippocampus,prevented the synaptic loss, partially restored the expression levels of synaptic-associated proteins, and improved the learning and memory abilities of APP/PS1_DT mice. Our results also suggested that the α7 nAChR interacted with Aβby mediated by Ca M-Ca MKⅡ-CREB signalling pathway, which was imbalanced by deposition of Aβ.
