Racchi M, Sironi M, Caprera A, König G, Govoni S
Dept of Experimental and Applied Pharmacology, University of Pavia, Italy.
Mol Psychiatry. 2001 Sep;6(5):520-8. doi: 10.1038/sj.mp.4000878.
We have investigated the acute and chronic effect of metrifonate (MTF) and dichlorvos (DDVP), respectively the prodrug and active acetylcholinesterase inhibitor, on the secretory processing of the amyloid precursor protein (APP) in SH-SY5Y neuroblastoma cells. We demonstrate that the acute treatment of SH-SY5Y cells with both compounds results in an increased secretion of the soluble fragment of APP (sAPPalpha) into the conditioned media of cells, with a pattern correlated to the level of acetycholinesterase inhibition. The regulation of APP processing in these conditions is mediated by an indirect cholinergic effect on muscarinic receptors, as demonstrated by inhibition with atropine. We have also followed APP expression and metabolism after long-term treatment with metrifonate. Treated cells showed reduced AChE activity after 24, 48 h and also following 7 days of repeated treatment, a time point at which increased AChE expression was detectable. At all time points sAPPalpha release was unaffected suggesting that enhanced sAPPalpha release by MTF is transitory, nevertheless the sensitivity of cholinergic receptors was unchanged, as indicated by the fact that cholinergic response can be elicited similarly in untreated and treated cells. APP gene expression was unaffected by long-term AChE inhibition suggesting that increased short-term sAPPalpha release does not elicit compensatory effects.
我们分别研究了敌百虫（MTF）和敌敌畏（DDVP）（前者为前体药物，后者为活性乙酰胆碱酯酶抑制剂）对SH-SY5Y神经母细胞瘤细胞中淀粉样前体蛋白（APP）分泌加工的急性和慢性影响。我们证明，用这两种化合物对SH-SY5Y细胞进行急性处理会导致APP可溶性片段（sAPPα）分泌到细胞条件培养基中的量增加，其模式与乙酰胆碱酯酶抑制水平相关。在这些条件下，APP加工的调节是由对毒蕈碱受体的间接胆碱能作用介导的，这一点通过阿托品抑制得以证明。我们还追踪了用敌百虫长期处理后APP的表达和代谢情况。处理后的细胞在24、48小时以及重复处理7天后乙酰胆碱酯酶（AChE）活性降低，而在这个时间点可检测到AChE表达增加。在所有时间点，sAPPα的释放均未受影响，这表明敌百虫增强sAPPα释放是短暂的，不过胆碱能受体的敏感性未变，这一点由未处理和处理过的细胞中能类似地引发胆碱能反应这一事实表明。长期抑制AChE对APP基因表达没有影响，这表明短期sAPPα释放增加不会引发代偿效应。
