Abstracts

Rationale: The functional network of human induced pluripotent stem cell (hiPSC)-derived neurons is a potentially powerful in vitro model for evaluating drug toxicity. Epileptiform activity is one of toxicological phenomena in central nervous system. We have developed toxicological evaluation assay in cultured hiPSC-derived neurons using multi-electrode arrays system. Methods: To evaluate the dynamics of epileptiform activities and the effect of anti-convulsant drug in cultured hiPSC-derived neurons, we used the high-throughput multielectrode array (MEA) system, where we simultaneously record extracellular potentials for 16 channels per well across 24-well plates. Human iPSC-derived cortical neurons were cultured on MEAs chip. Spike analyses were performed using Mobius software (Alpha Med Scientific) and MATLAB.  Results: We firstly confirmed the modulation of activity by typical glutamatergic and GABAergic receptor antagonists/agonists in spontaneous firings. Spontaneous activities and typical responses against synaptic related drugs were detected with high S/N ratio using high-throughput MEA system. Next, we examined chemically evoked epileptiform activity. Electrophysiological seizes were induced by pentylentetrazole (PTZ), 4-Aminopyridine (4-AP), kainic acid (KA) and so on, the most widely used chemical convulsant in animal models to screen for new anti-epilepsy drugs. We also examined the anti-convulsant effects of common clinical anti-epilepsy drugs (AEDs), phenytoin. PTZ, 4-AP and KA induced an increase in synchronized burst firings (SBFs) in a concentration-dependent manner. Phenytoin suppressed induced epileptiform activity. However, the patterns of epileptiform activities and phenytoin effects were different with respect to each epilepsy drugs. Conclusions: From these results, we suggest that the electrophysiological assay in cultured human iPSC-derived neuron using high-throughput MEA system is a useful to investigate the neuronal toxicity in drug screening and pharmacological effects of human neurological disease.In addition, our assay can be adapted to iPSC-derived neurons from epilepsy patients.  Funding: iPSC Non-Clinical Experiments for Nervous System project