Aβ42寡聚体对突触内外谷氨酸受体表达的影响  

Effects of Aβ42 oligomers on expression of synaptic and extrasynaptic glutamate receptors

作　　者：陈秋旋 贺娅旎 刘玉香 冯一[1] 张珂珂 魏伟[1] CHEN Qiuxuan;HE Yani;LIU Yuxiang;FENG Yi;ZHANG Keke;WEI Wei(Department of Pathophysiology,Key Laboratory of National Administration of Traditional Chinese Medicine,School of Medicine,Jinan University,Guangzhou 510632,China)

机构地区：[1]暨南大学基础医学与公共卫生学院病理生理学系,国家中医药管理局病理生理实验室,广东广州510632

出　　处：《中国病理生理杂志》2024年第6期1025-1032,共8页Chinese Journal of Pathophysiology

基　　金：广东省自然科学基金资助项目(No.2023A1515010585);广州市科技计划项目(No.201904010040)。

摘　　要：目的:通过体内外实验探讨阿尔茨海默病关键发病分子β-淀粉样蛋白42寡聚体(Aβ42Os)作用下离子型谷氨酸受体N-甲基-D-天冬氨酸受体(NMDAR)亚基(NR2A、NR2B和NR1)和代谢型谷氨酸受体5(mGluR5)在突触内外的表达分布变化。方法:(1)用不同浓度的Aβ42Os处理乳小鼠原代神经元,Western blot和免疫荧光染色检测原代神经元中mGluR5和NMDAR的表达和分布情况。(2)在C57BL/6小鼠侧脑室立体定位注射不同浓度的Aβ42Os,Western blot检测海马组织中mGluR5和NMDAR在突触内外的蛋白水平,以及mGluR5下游磷脂酰肌醇3-激酶(PI3K)/蛋白激酶B(PKB/AKT)信号通路相关蛋白、钙信号下游通路相关蛋白和突触相关蛋白的表达。结果:(1)高浓度Aβ42Os处理原代小鼠神经元增加mGluR5表达(P<0.01),减少NR2A、NR2B和NR1表达(P<0.01);引起mGluR5膜表面聚集,而使NR2A、NR2B和NR1膜表面表达分布减少。(2)高浓度Aβ42Os引起小鼠海马组织中突触mGluR5表达增加(P<0.01),NR2A(P<0.05)和NR2B(P<0.01)表达减少,突触外NR2B表达增加(P<0.01);抑制PI3K表达及AKT和细胞外信号调节激酶(ERK)磷酸化,过度激活钙/钙调蛋白依赖性蛋白激酶IIα(CaMKIIα);引起突触后致密蛋白95、亲棘蛋白(spinophilin)、突触小泡蛋白(synaptophysin)和微管相关蛋白2表达减少(P<0.01)。结论:(1)高浓度Aβ42Os引起神经元突触mGluR5过度聚集,NR2A、NR2B和NR1表达减少,而突触外NR2B表达增加。(2)高浓度Aβ42Os抑制PI3K/AKT和ERK信号通路,过度激活CaMKIIα通路,损伤突触结构。AIM:To explore the expression and distribution of synaptic and extrasynaptic glutamate receptors under the action of amyloidβ-protein 42 oligomers(Aβ42Os)in Alzheimer disease.METHODS:In vitro,primary neurons from neonatal mice were treated with different concentrations of Aβ42Os.In vivo,Aβ42Os were stereotaxically injected into the lateral ventricle of C57BL/6 mice.Western blot was used to detect the protein levels of metabotropic gultamate receptor 5(mGluR5)and N-methyl-D-aspartate receptor(NMDAR)subunits(NR2A,NR2B and NR1)in mouse primary neurons and mice.Immunofluorescence staining was performed to observe the distribution of mGluR5 and NMDAR.Additionally,Western blot was employed to examine the expression of mGluR5 downstream phosphatidylinositol 3-kinase(PI3K)/protein kinase B(PKB/AKT)signaling pathway-related proteins,calcium signaling pathway-related proteins and synapse-related proteins in mouse hippocampal tissues.RESULTS:(1)High concentrations of Aβ42Os increased mGluR5 expression in mouse primary neurons,but reduced the expression of NR2A,NR2B and NR1(P<0.01).Treatment of primary neurons with high concentration of Aβ42Os resulted in aggregation of mGluR5 on the membrane surface,and reduced the expression of NR2A,NR2B and NR1 on the membrane surface.(2)High concentration of Aβ42Os increased the expression of synaptic mGluR5 in mouse hippocampal tissues(P<0.01),but reduced the expression of synaptic NR2A(P<0.05)and NR2B(P<0.01)and increased the expression of extrasynaptic NR2B(P<0.01).High concentration of Aβ42Os inhibited the expression of PI3K and the phosphorylation of AKT and extracellular signal-regulated kinase(ERK),and overactivated calcium/calmodulin-dependent protein kinase IIα(CaMKIIα).High concentration of Aβ42 decreased the expression of postsynaptic density protein 95,spinophilin,synaptophysin and microtubule-associated protein 2(P<0.01).CONCLUSION:(1)High concentrations of Aβ42Os increase mGluR5 expression and decrease NR2A,NR2B and NR1 expression in synapse,along with an increa

关 键 词：阿尔茨海默病 β-淀粉样蛋白42寡聚体 代谢型谷氨酸受体5 N-甲基-D-天冬氨酸受体 突触 

分 类 号：R742[医药卫生—神经病学与精神病学] R363.2[医药卫生—临床医学] R971