Functional analysis of copper homeostasis in cell culture models: a new perspective on internal copper transport
Functional analysis of copper homeostasis in cell culture models: a new perspective on internal copper transport
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DOI：
10.1093/ajcn/67.5.988s
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发表时间：
1998-05-01
影响因子：
7.1
通讯作者：
Reedy, MCM
中科院分区：
文献类型：
--
作者：
Harris, ED;Qian, YC;Reedy, MCM
铜离子穿过重要器官和组织的膜屏障的运动是营养学中的优先主题，并且仍然对其机制知之甚少。膜结合，铜转运腺苷三磷酸酶（Cu-ATP酶）的报告选择性铜离子带来了新的焦点问题，并促使新的想法。使用细胞培养模型的方法，我们试图了解是否运输进出细胞依赖于Cu-ATPase。在成纤维细胞，脑胶质细胞，神经母细胞瘤细胞和胎盘细胞的运输动力学的测量显示铜的吸收率和巯基试剂的反应的差异。Be Wo细胞是一种人绒毛膜癌胎盘细胞系，其行为与Menkes成纤维细胞一样，通过贪婪地吸收铜但不将铜释放到直接环境中。进一步的测试表明，Be Wo细胞不表达已被鉴定为Menkes综合征的膜结合Cu-ATPase的转录本。然而，转录诱导是通过在允许顶端和基底侧表面形成的多孔过滤器上生长Be Wo细胞来实现的。随着转录表达，细胞显示出将铜释放到培养基中的能力。Be Wo细胞还合成了一种形式的血浆铜蓝蛋白，其结构与血浆蛋白不同，因此可能是不同基因的产物。Be Wo细胞也可能表达Wilson病的基因，从而将Menkes和Wilson蛋白与母亲的铜传递联系起来。我们构建了一个模型，其中两种ATP酶在一个基于囊泡的运输机制中协同工作。囊泡模型可以帮助我们理解铜在胎盘和所有细胞中的转运。
The movement of copper ions across membrane barriers of vital organs and tissues is a priority topic in nutrition and one for which there continues to be little understanding of the mechanism. Reports of membrane-bound, copper-transporting adenosine triphosphatases (Cu-ATPases) selective for copper ions have brought new focus to the problem and prompted fresh ideas. Using a cell culture model approach, we attempted to learn whether transport into and out of cells depends on a Cu-ATPase. Measurement of transport kinetics in fibroblasts, brain glial cells, neuroblastoma cells, and placental cells showed differences in the rates of copper uptake and response to sulfhydryl reagents. Be Wo cells, a human choriocarcinoma placental cell line, behaved as did Menkes fibroblasts by avidly absorbing copper but not releasing copper to the immediate environment. Further tests showed that Be Wo cells did not express the transcript for the membrane-bound Cu-ATPase that has been identified with Menkes syndrome. Transcript induction, however, was achieved by growing Be Wo cells on porous filters that allowed apical and basolateral surfaces to form. With transcript expression, the cells showed a capacity to release copper into the medium. Be Wo cells also synthesized a form of ceruloplasmin whose structure differed from that of the plasma protein and hence may be a product of a different gene. Be Wo cells may also express the gene for Wilson disease, thus linking Menkes and Wilson proteins to maternal delivery of copper. We constructed a model in which both ATPases work in concert in a vesicle-based transport mechanism. The vesicle model may help us understand the transport of copper across the placenta and all cells in general.