An evaluation of a human stem cell line to identify risk of developmental neurotoxicity with antiepileptic drugs

• Human stem cells may aid the evaluation of neurotoxicity with psychotropic drugs.
• Antiepileptics impaired differentiation of human stem cells into neurons.
• The impact of antiepileptics on stem cells in vitro correlated with risk in vivo.
• Exploiting stem cells in vitro may improve predictive neurotoxicology in vivo.

Determination of the impact of a drug on human brain development relies instead on surrogate animal studies. Here we have exploited the human stem cell line, TERA2.cl.SP12 to differentiate into neurons and addressed their value as an in vitro model to evaluate the risk of developmental neurotoxicity with antiepileptic drugs (AEDs). The effects of four AEDs were investigated on cell viability, cell cycle and neural differentiation. Exposure to either phenobarbital (10–1000 μM), valproic acid (10–1000 μM), lamotrigine (1–100 μM) or carbamazepine (1–100 μM) for 3 days reduced viability in non-differentiating cells only at the highest concentrations tested. Viability was also reduced with lower concentrations of all AEDs in cells undergoing neural differentiation. Valproic acid and carbamazepine increased DNA fragmentation and reduced cell cycle progression. 3 days exposure at the start of neural differentiation to phenobarbital, valproic acid or lamotrigine also significantly reduced the proportion of stem cells that subsequently differentiated into neurons at 15 days in vitro. The two control agents tested, ciprofloxacin and perfluorooctanoic acid had no impact on neurogenesis in vitro. These new data show that modelling neurogenesis in vitro using a human stem cell line may be a powerful method to predict risks of developmental neurotoxicity in vivo with psychotropic drugs.