Evaluation of developmental toxicants and signaling pathways in a functional test based on the migration of human neural crest cells

Abstract

BACKGROUND: Information on the potential developmental toxicity (DT) of the majority of chemicals is scarce, and test capacities for further animal-based testing are limited. Therefore, new approaches with higher throughput are required. A screening strategy based on the use of relevant human cell types has been proposed by the EPA and others. As impaired neural crest (NC) function is one of the known causes for teratologic effects, testing of toxicant effects on NC is desirable for a DT test battery.OBJECTIVE: To develop a robust and widely applicable human-relevant NC function assay, allowing sensitive screening of environmental toxicants, and a definition of toxicity pathways.METHODS: We generated NC cells from human embryonic stem cells, and after establishing a migration assay of NC (MINC), we tested environmental toxicants as well as inhibitors of physiological signal transduction pathways.RESULTS: Methylmercury (50 nM), valproic acid (> 10 µM) and Lead-acetate (1 µM) affected migration of NC more potently than migration of other cell types. The MINC assay correctly identified the neural crest toxicants triadimefon and triadimenol, additionally it showed different sensitivities to various organic and inorganic mercury compounds. Applying classic pharmacologic inhibitors and large-scale microarray gene expression profiling, we found several signaling pathways that are relevant for the migration of NC in the MINC.CONCLUSIONS: The MINC assay faithfully models human NC migration, and reveals impairment of this function by developmental toxicants with good sensitivity and specificity.