Toxicity testing is a crucial step in the development and approval of chemical compounds for human contact and consumption. However, existing model systems often fall short in their prediction of human toxicity in vivo because they may not sufficiently recapitulate the human physiology. The complexity of three-dimensional (3D) human organ-like cell culture systems (“organoids”) can generate potentially more relevant models of human physiology and disease, including toxicity predictions. However, so far, the inherent biological heterogeneity and cumbersome generation and analysis of organoids has rendered efficient, unbiased, high throughput evaluation of toxic effects in these systems challenging. Recent advances in both standardization and quantitative fluorescent imaging enabled us to dissect the toxicities of compound exposure to separate cellular subpopulations within human organoids at the single cell level in a framework that is compatible with high throughput approaches. Screening a library of 84 compounds in standardized human automated midbrain organoids (AMOs) generated from two independent cell lines correctly recognized known nigrostriatal toxicants. This approach further identified the flame retardant 3,3’,5,5’-tetrabromobisphenol A (TBBPA) as a selective toxicant for dopaminergic neurons in the context of human midbrain-like tissues for the first time. Results were verified with high reproducibility in more detailed dose-response experiments. Further, we demonstrate higher sensitivity in 3D AMOs than in 2D cultures to the known neurotoxic effects of the pesticide lindane. Overall, the automated nature of our workflow is freely scalable and demonstrates the feasibility of quantitatively assessing cell type-specific toxicity in human organoids in vitro.

中文翻译：

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人中脑类器官的细胞类型特异性高通量毒性测试

毒性测试是开发和批准用于人类接触和消费的化合物的关键步骤。然而，现有的模型系统通常无法预测人体体内毒性，因为它们可能无法充分概括人体生理学。三维 (3D) 人体器官样细胞培养系统（“类器官”）的复杂性可以产生潜在的更相关的人体生理学和疾病模型，包括毒性预测。然而，到目前为止，类器官固有的生物异质性和繁琐的生成和分析使得对这些系统中毒性效应的高效、公正、高通量评估具有挑战性。标准化和定量荧光成像的最新进展使我们能够在与高通量方法兼容的框架中，在单细胞水平上剖析化合物暴露于人体类器官内不同细胞亚群的毒性。筛选由两个独立细胞系生成的标准化人类自动化中脑类器官 (AMO) 中的 84 种化合物库，正确识别了已知的黑质纹状体毒物。这种方法进一步首次将阻燃剂 3,3',5,5'-四溴双酚 A (TBBPA) 鉴定为人类中脑样组织中多巴胺能神经元的选择性毒物。结果在更详细的剂量反应实验中得到了高度可重复性的验证。更远，我们证明 3D AMO 比 2D 培养对农药林丹的已知神经毒性作用具有更高的敏感性。总体而言，我们工作流程的自动化性质可自由扩展，并证明了在体外定量评估人体类器官中细胞类型特异性毒性的可行性。