LONG AMYLOID BETA-PROTEIN SECRETED FROM WILD-TYPE HUMAN NEUROBLASTOMA IMR-32 CELLS
LONG AMYLOID BETA-PROTEIN SECRETED FROM WILD-TYPE HUMAN NEUROBLASTOMA IMR-32 CELLS
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DOI：
10.1021/bi00032a022
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发表时间：
1995-08-15
期刊：
影响因子：
2.9
通讯作者：
SUZUKI, N
中科院分区：
文献类型：
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作者：
ASAMIODAKA, A;ISHIBASHI, Y;SUZUKI, N
在阿尔茨海默病中，39到43个氨基酸的淀粉样β蛋白(Aβ)以淀粉样蛋白的形式沉积。最近的研究表明，短Aβ(Aβ(39)或Aβ(40))和长Aβ(Aβ(42)或Aβ(43))在阿尔茨海默病类型的病理中扮演着不同的角色。然而，很少有人试图单独研究短的和长的Aβ产生的细胞机制。在本报告中，我们首先使用区分长Aβ和短Aβ的高灵敏夹心ELISA，测量了具有神经元或神经胶质样特性的野生型人和啮齿动物细胞分泌的短Aβ和长Aβ的量。结果表明，所有细胞分泌的长Aβ约占总Aβ的10%。为了鉴定Long Aβ的分子种类，我们接下来通过亲和层析、凝胶过滤高效液相色谱和反相高效液相色谱分离了人神经母细胞瘤IMR-32细胞分泌的Aβ种类。质谱分析明确表明，IMR-32细胞产生Aβ(1-42)，同时产生Aβ(1-37)、Aβ(1-38)、Aβ(1-39)，最主要的是Aβ(1-40)。最后，为了研究产生Aβ(1-42)的细胞机制，我们研究了灯盏花素A和莫能菌素对IMR-32细胞产生Aβ(1-40)和Aβ(1-42)的影响。这些试剂以浓度依赖的方式同时减少BASH Aβ(1-40)和Aβ(1-42)的产生。这些结果表明，处理野生型淀粉样前体蛋白通常会产生Aβ(1-42)，其比例为10%，并且Aβ(1-40)和Aβ(1-42)具有共同的分泌机制，涉及酸性间隔，如高尔基体晚期或早期内小体。
The 39- to 43-amino acid amyloid beta-protein (A beta) is deposited as amyloid in Alzheimer's disease. Recent studies have suggested that short A beta (A beta(39) or A beta(40)) and long A beta (A beta(42) or A beta(43)) play different roles in Alzheimer-type pathology. However, little attempt has been made to investigate the cellular mechanisms underlying the generation of short and long A beta individually. In the present report, we first measured the amount of short and long A beta that are secreted from wild-type human and rodent cells with neuron- or glia-like properties using highly sensitive sandwich-ELISAs that discriminate long A beta from short A beta. The results showed that long A beta secreted by all cells constitutes approximately 10% of the total A beta. To identify the molecular species of long A beta, we next isolated the A beta species secreted from human neuroblastoma IMR-32 cells by affinity chromatography, gel-filtration HPLC, and reverse-phase HPLC. Mass spectrometric analysis demonstrated unequivocally that IMR-32 cells produce A beta(1-42) together with A beta(1-37), A beta(1-38), A beta(1-39), and most predominantly, A beta(1-40). Finally, to investigate the cellular mechanisms that generate A beta(1-42), we studied the effects of brefeldin A and monensin on the production of A beta(1-40) and A beta(1-42) in IMR-32 cells. These reagents reduced the production of bath A beta(1-40) and A beta(1-42) simultaneously in a concentration-dependent manner. These results indicate that processing of wild-type amyloid precursor protein normally generates A beta(1-42) at a ratio of 10% to total A beta and that A beta(1-40) and A beta(1-42) share a common secretory mechanism that involves acidic compartments such as the late Golgi or early endosomes.