Abstract

Background:

Inhibition of acetylcholinesterase (AChE), a biomarker of organophosphorous and carbamate exposure in environmental and occupational human health, has been commonly used to identify potential safety liabilities. So far, many environmental chemicals, including drug candidates, food additives, and industrial chemicals, have not been thoroughly evaluated for their inhibitory effects on AChE activity. AChE inhibitors can have therapeutic applications (e.g., tacrine and donepezil) or neurotoxic consequences (e.g., insecticides and nerve agents).

Objectives:

The objective of the current study was to identify environmental chemicals that inhibit AChE activity using in vitro and in silico models.

Methods:

To identify AChE inhibitors rapidly and efficiently, we have screened the Toxicology in the 21st Century (Tox21) 10K compound library in a quantitative high-throughput screening (qHTS) platform by using the homogenous cell-based AChE inhibition assay and enzyme-based AChE inhibition assays (with or without microsomes). AChE inhibitors identified from the primary screening were further tested in monolayer or spheroid formed by SH-SY5Y and neural stem cell models. The inhibition and binding modes of these identified compounds were studied with time-dependent enzyme-based AChE inhibition assay and molecular docking, respectively.

Results:

A group of known AChE inhibitors, such as donepezil, ambenonium dichloride, and tacrine hydrochloride, as well as many previously unreported AChE inhibitors, such as chelerythrine chloride and cilostazol, were identified in this study. Many of these compounds, such as pyrazophos, phosalone, and triazophos, needed metabolic activation. This study identified both reversible (e.g., donepezil and tacrine) and irreversible inhibitors (e.g., chlorpyrifos and bromophos-ethyl). Molecular docking analyses were performed to explain the relative inhibitory potency of selected compounds.

Conclusions:

Our tiered qHTS approach allowed us to generate a robust and reliable data set to evaluate large sets of environmental compounds for their AChE inhibitory activity. https://doi.org/10.1289/EHP6993

中文翻译：

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分析用于乙酰胆碱酯酶抑制的 Tox21 化学集合

摘要

背景：

乙酰胆碱酯酶 (AChE) 的抑制作用是环境和职业人类健康中有机磷和氨基甲酸酯暴露的生物标志物，通常用于识别潜在的安全责任。迄今为止，许多环境化学品，包括候选药物、食品添加剂和工业化学品，尚未对它们对 AChE 活性的抑制作用进行彻底评估。AChE 抑制剂可以具有治疗应用（例如，他克林和多奈哌齐）或神经毒性后果（例如，杀虫剂和神经毒剂）。

目标：

当前研究的目的是使用体外和计算机模型确定抑制 AChE 活性的环境化学物质。

方法：

为了快速有效地鉴定 AChE 抑制剂，我们在定量高通量筛选 (qHTS) 平台中使用基于细胞的同质 AChE 抑制测定和基于酶的 AChE 抑制筛选了 21 世纪毒理学 (Tox21) 10K 化合物库化验（有或没有微粒体）。从初步筛选中确定的 AChE 抑制剂在由 SH-SY5Y 和神经干细胞模型形成的单层或球体中进一步测试。分别使用基于时间依赖性酶的 AChE 抑制测定和分子对接研究了这些鉴定化合物的抑制和结合模式。

结果：

本研究确定了一组已知的 AChE 抑制剂，如多奈哌齐、二氯化氨苯溴铵和盐酸他克林，以及许多以前未报道的 AChE 抑制剂，如氯化白屈菜红碱和西洛他唑。许多这些化合物，如吡唑磷、膦酮和三唑磷，需要代谢活化。该研究确定了可逆（例如，多奈哌齐和他克林）和不可逆抑制剂（例如，毒死蜱和溴磷）。进行分子对接分析以解释所选化合物的相对抑制效力。

结论：

我们的分层 qHTS 方法使我们能够生成强大而可靠的数据集，以评估大量环境化合物的 AChE 抑制活性。https://doi.org/10.1289/EHP6993