Using High-Throughput Screening to Evaluate Perturbations Potentially Linked to Neurobehavioral Outcomes: A Case...

There is growing evidence from human and animal studies indicating an association between exposure to synthetic food dyes and adverse neurobehavioral outcomes in children. However, data gaps persist for potential mechanisms by which the synthetic food dyes could elicit neurobehavioral impacts. We developed an approach to evaluate seven US FDA-batch-certified food dyes using publicly available high-throughput screening (HTS) data from the US EPA's Toxicity Forecaster to assess potential underlying molecular mechanisms that may be linked to neurological pathway perturbations. The dyes were screened through 270 assays identified based on whether they had a neurological-related gene target and/or were mapped to neurodevelopmental processes or neurobehavioral outcomes, and were conducted in brain tissue, targeted specific hormone receptors, or targeted oxidative stress and inflammation. Some results provided support for neurological impacts found in human and animal studies, while other results showed a lack of correlation with in vivo findings. The azo dyes had a range of activity in assays mapped to G-protein-coupled receptors and were active in assays targeting dopaminergic, serotonergic, and opioid receptors. Assays mapped to nuclear receptors (androgen, estrogen, and thyroid hormone) also exhibited activity with the food dyes. Other molecular targets included the aryl hydrocarbon receptor, acetylcholinesterase, and monoamine oxidase. The Toxicological Prioritization Index tool was used to visualize the results of the Novascreen assays. Our results highlight certain limitations of HTS assays but provide insight into potential underlying mechanisms of neurobehavioral effects observed in in vivo animal toxicology studies and human clinical studies.