Isoform-specific proteolysis of apolipoprotein-E in the brain
Isoform-specific proteolysis of apolipoprotein-E in the brain
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DOI：
10.1016/j.neurobiolaging.2009.02.006
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发表时间：
2011-02-01
影响因子：
4.2
通讯作者：
Garner, Brett
中科院分区：
文献类型：
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作者：
Elliott, David A.;Tsoi, Kayan;Garner, Brett
载脂蛋白-E (apoE) 在神经生物学中发挥着重要作用，apoE4 亚型会增加患阿尔茨海默病 (AD) 的风险。 ApoE 肽具有生物活性，可能在大脑中产生。目前尚不清楚 apoE 蛋白水解是否依赖于同种型或 AD 状态，这一点已在此处解决。将海马、额叶皮质、枕叶和小脑样品匀浆成可溶于 Tris 缓冲盐水 (TBS)、Triton X-100 或盐酸胍的级分，并通过蛋白质印迹分析 apoE 片段。大约 20% 的 apoE3 被检测为片段，并且主要是 TBS 可溶级分中的 25 kDa 肽。与 apoE4 受试者相比，apoE3 受试者中 TBS 可溶性 apoE 片段的浓度高出两到三倍。在所检查的大脑的所有区域中都观察到这种差异，并且与 AD 状态无关。组织蛋白酶-D 处理产生的 apoE 片段与在大脑中检测到的片段非常相似，但是，没有检测到组织蛋白酶-D 蛋白水解敏感性方面的 apoE 异构体特异性差异。这表明，apoE 在人脑中形成可溶性片段的蛋白水解过程取决于 apoE 亚型，而不是 AD 状态。 (C) 2009 Elsevier Inc. 保留所有权利。
Apolipoprotein-E (apoE) plays important roles in neurobiology and the apoE4 isoform increases risk for Alzheimer's disease (AD). ApoE peptides are biologically active and may be produced in the brain. It is unclear if apoE proteolysis is dependent on isoform or AD status and this was addressed here. Hippocampus, frontal cortex, occipital lobe and cerebellum samples were homogenized into fractions that were soluble in Tris-buffered saline (TBS), Triton X-100 or guanidine hydrochloride and analysed for apoE fragmentation by Western blotting. Approximately 20% of apoE3 was detected as fragments and this was predominantly as a 25 kDa peptide in TBS-soluble fractions. The concentration of TBS-soluble apoE fragments was two- to three-fold higher in apoE3 compared to apoE4 subjects. This difference was observed in all areas of the brain examined and was not related to AD status. Cathepsin-D treatment generated apoE fragments that were very similar to those detected in brain, however, no apoE isoform-specific differences in susceptibility to cathepsin-D proteolysis were detected. This indicates that proteolytic processing of apoE to form soluble fragments in the human brain is dependent on apoE isoform but not AD status. (C) 2009 Elsevier Inc. All rights reserved.