Mass Spectrometric Enzyme Histochemistry Method Developed for Visualizing In Situ Cholinesterase Activity in Mus musculus and Drosophila melanogaster
Mass Spectrometric Enzyme Histochemistry Method Developed for Visualizing In Situ Cholinesterase Activity in Mus musculus and Drosophila melanogaster
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DOI：
10.1021/acs.analchem.0c02106
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发表时间：
2020-09-15
影响因子：
7.4
通讯作者：
Shimma, Shuichi
中科院分区：
文献类型：
--
作者：
Takeo, Emi;Fukusaki, Eiichiro;Shimma, Shuichi
酶组织化学促进酶活性原位可视化;然而，由于它是基于颜色的方法，分子定量是禁止的。本研究旨在建立一种半定量、基于质谱成像（MSI）的内源性胆碱酯酶（ChE）酶组织化学检测方法。使用氘标记的乙酰胆碱（ACh-d9）作为底物，以区分ACh-d9和胆碱-d9从内源性乙酰胆碱和胆碱，分别，从头胆碱酯酶活性的异质性本地化可视化使用MSI，没有来自原位因素的干扰。此外，涉及两个胆碱酯酶抑制剂在小鼠大脑中的组织抑制剂测定揭示了特定的胆碱酯酶抑制胼胝体。据我们所知，这项研究是第一个报告的可视化方法，总胆碱酯酶活性的神经节和腹部的果蝇，表明其适用于不同的动物。目前的结果提供了新的见解，酶组织化学的适用性，通过MSI的低分子量有机化合物的代谢（即，“小分子”）和半定量能力，表明MSI酶组织化学可能成为异质组织研究的有力工具。
Enzyme histochemistry facilitates enzyme activity visualization in situ; however, as it is a color-based method, molecular quantification is prohibitive. This study aimed to develop a semiquantitative, mass spectrometry imaging (MSI)-based enzyme histochemistry method to determine endogenous cholinesterase (ChE) activity. Using deuterium-labeled acetylcholine (ACh-d9) as a substrate to distinguish ACh-d9 and choline-d9 from endogenous acetylcholine and choline, respectively, the heterogeneous localization of de novo ChE activity was visualized using MSI, devoid of interferences from in situ factors. Furthermore, a tissue inhibitor assay involving two ChE inhibitors in the mouse brain revealed specific ChE inhibition in the corpus callosum. To the best of our knowledge, this study is the first to report a visualization method for total ChE activity in the ganglia and abdomen in Drosophila melanogaster, indicating its applicability among different animals. The present results provide novel insights into the applicability of enzyme histochemistry via MSI to the metabolism of low-molecular-weight organic compounds (i.e., "small molecules") and semiquantitative capability, suggesting that MSI enzyme histochemistry may become a powerful tool for heterogeneous tissue studies.