Regulation of choline acetyltransferase activity by cell density in a cultured human neuroblastoma cell line.
Regulation of choline acetyltransferase activity by cell density in a cultured human neuroblastoma cell line.
复制标题
在培养的人神经母细胞瘤细胞系中通过细胞密度调节胆碱乙酰转移酶活性。
DOI：
10.1159/000111975
复制
发表时间：
1988
影响因子：
2.9
通讯作者：
Davies,P
中科院分区：
文献类型：
--
作者：
Casper,D;Davies,P
胆碱乙酰转移酶（Choline acetyltransferase, ChAT）是乙酰胆碱代谢的生物合成酶，在人胆碱能神经母细胞瘤细胞系中表达；MC-IXC。我们证明，ChAT活性在该细胞系中受细胞密度调节。据认为，刺激酶活性的机制涉及细胞接触，因为由高密度细胞调节的培养基不能模拟单独的密度效应，胰蛋白酶化逆转了这种效应。在MC-IXC培养中，密度没有增加乙酰胆碱酯酶活性，这是胆碱能表型的另一个标志，表明这两种胆碱能酶的独立调节。由于增加的密度减慢了细胞分裂的速度，我们使用了DNA合成抑制剂来从细胞密度中分离DNA复制。这对ChAT的特异性活性没有影响，表明细胞-细胞接触是中介因素。对其他神经母细胞瘤细胞系进行了测试，只有已经含有ChAT活性的细胞系对细胞间接触对其调节敏感，这表明细胞间接触在这一过程中是允许的，而不是指导性的。我们还讨论了细胞传代对ChAT活性的影响。
Choline acetyltransferase (ChAT), the biosynthetic enzyme for acetylcholine metabolism, is expressed in a human cholinergic neuroblastoma cell line; MC-IXC. We demonstrate that ChAT activity is regulated in this cell line by cell density. It is believed that the mechanism of stimulation of enzyme activity involves cellular contact, as medium conditioned by cells of high density failed to mimic the effect of density alone, and trypsinization reversed this effect. Density did not increase acetylcholinesterase activity, another marker for the cholinergic phenotype, in MC-IXC cultures, demonstrating the independent regulation of these two cholinergic enzymes. Since increased density slows the rate of cell division, we used a DNA synthesis inhibitor to uncouple DNA replication from cell density. This had no effect on the specific activity of ChAT, suggesting that a cell-cell contact was the mediating factor. Other neuroblastoma cell lines were tested, and only cell lines which already contain ChAT activity were sensitive to its regulation by cell-cell contact, suggesting that cell-cell contact is permissive rather than instructive in this process. The effect of cell passage on ChAT activity is also discussed.