Evaluation of neurotoxicity of drugs from morphological and electrophysiological endpoints using human iPSC-derived neural cell models.

INTRODUCTION: Genome-edited human induced pluripotent stem cells (iPSCs) were first generated in 2007, and have been applied in pharmaceutical research, development, and clinical therapy as an in vitro platform for personalised phenotyping and drug discovery. iPSCs can differentiate into multiple types of neural cells, the in vitro hiPSC-derived neural model may also be an effective tool for early screening and evaluating potential neurotoxicants. Neurotoxicity is one of the limiting factors in the clinical application of many drugs. However, there is currently no set of standardized in vitro evaluation procedures and regulatory guidance documents for preclinical safety evaluation of new drugs, and traditional animal testing methods, including histopathological examination and behavioural testing, are inadequate for assessing the therapeutic effects and neurotoxicity of neurotherapeutic drugs.

METHODS: In this study, we developed a hiPSC-derived neural model that is suitable for testing neurospecific morphology and electrophysiology endpoints.

RESULTS: The research results showed that oxaliplatin and emodin at concentrations higher than 10 μg/mL, phenytoin sodium at concentrations exceeding 50 μg/mL, acrylamide and amantadine at concentrations exceeding 100 μg/mL, as well as aconitine and isoniazid (100 μg/mL) have a toxic effect on neurite outgrowth (p<0.05, p<0.01). No significant neurite outgrowth toxicity was observed in any of the dose groups of ethambutol. In MEA detection, phenytoin sodium and amantadine reduced the Number of Spikes, Mean Firing Rates, Number of Bursts, and Synchrony Index in a concentration-dependent manner. Phenytoin sodium, amantadine, and nano-Iron oxide all exhibited potent inhibitory effects on neuronal firing. Ethambutol exhibited a time-dependent and dose-dependent excitatory/inhibitory effect. The effect of isoniazid on neural electrical activity shifted from inhibition to excitation with the increase of administration dose and the extension of exposure time. This model enables a more comprehensive evaluation of neurotoxicity in neurotherapeutic drugs, nano-pharmaceuticals, and environmental organic compounds from the perspective of changes in neurite outgrowth and neural network functionality.

DISCUSSION: The method has specific test endpoints and high sensitivity, and can achieve high-throughput drug screening, which is expected to be applied to the safety risk assessment and scientific supervision of drugs with potential neurotoxicity, especially various types of neurotherapeutic drugs.