Apolipoprotein E enhances uptake of soluble but not aggregated amyloid-β protein into synaptic terminals
Apolipoprotein E enhances uptake of soluble but not aggregated amyloid-β protein into synaptic terminals
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DOI：
10.1046/j.1471-4159.2003.01643.x
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发表时间：
2003-03-01
影响因子：
4.7
通讯作者：
Cole, GM
中科院分区：
文献类型：
--
作者：
Gylys, KH;Fein, JA;Cole, GM
载脂蛋白E（apoE）影响阿尔茨海默病（AD）发病机制的细胞机制尚不清楚。我们研究了载脂蛋白E对外源性淀粉样蛋白β 1-40（A β 40）内化到大鼠脑粗突触体制剂中的影响。将可溶（在缓冲液中稀释1小时内）或聚集（在缓冲液中稀释前老化4天）形式的A β 40肽与脂化apoE预孵育，然后加入突触体;在用抗A β（10 G4）抗体免疫标记后，使用流式细胞术定量末端内淀粉样蛋白-β标记。与单独使用可溶性Abeta 40相比，使用可溶性Abeta/apoE混合物处理后，Abeta阳性突触体的数量增加（接近50%）。然而，当Abeta聚集时，形成较少的十二烷基硫酸钠（SDS）稳定的Abeta/apoE复合物，并且apoE的加入减少了Abeta阳性末端的数量。添加脂蛋白受体相关蛋白（LRP）拮抗剂受体相关蛋白（RAP）抑制apoE诱导的突触体Abeta增加，胰蛋白酶和肝素酶处理的对照证实了大多数可溶性Abeta的末端内定位。通过背根神经节（DRG）神经元的免疫细胞化学证实了apoE介导的Abeta标记增加。这些结果表明，与apoE的复合物形成增强了可溶性Abeta摄取进入末端的内化。
The cellular mechanism by which apolipoprotein E (apoE) affects the pathogenesis of Alzheimer's disease (AD) is not understood. We have examined the effect of apolipoprotein E on the internalization of exogenous amyloid-beta 1-40 (Abeta40) into a rat brain crude synaptosomal preparation. Abeta40 peptide in soluble (within 1 h of dilution in buffer) or aggregated (aged 4 days before dilution in buffer) form was pre-incubated with lipidated apoE then added to synaptosomes; intraterminal amyloid-beta labeling was quantified using flow cytometry following immunolabeling with the anti-Abeta (10G4) antibody. The number of Abeta-positive synaptosomes was increased (similar to50%) by treatment with a soluble Abeta/apoE mixture compared with treatment with soluble Abeta40 alone. However, when the Abeta was aggregated, less sodium dodecyl sulfate (SDS)-stable Abeta/apoE complex was formed and the addition of apoE decreased the number of Abeta-positive terminals. The addition of the lipoprotein-receptor related protein (LRP) antagonist receptor-associated protein (RAP) inhibited the apoE-induced increase in synaptosomal Abeta, and controls treated with trypsin and heparinase confirm intraterminal localization of the majority of the soluble Abeta. The apoE-mediated increase in Abeta labeling was confirmed in intact cells by immunocytochemistry of dorsal root ganglion (DRG) neurons. These results suggest that complex formation with apoE enhances internalization of soluble Abeta uptake into terminals.