Human Induced Pluripotent Stem Cells-Derived Neural Organoids as a Novel In Vitro Platform for Developmental Neurotoxicity Assessment

Rotenone is a neurotoxic substance that inhibits mitochondrial respiratory chain complex I, decreases ATP production and increases oxidative stress. It exhibits neurotoxic effects, particularly on dopamine-producing neurons, and is associated with the etiology of Parkinson’s disease. To better understand the impact of rotenone on neural development and function, we examined the effect of rotenone on gene expression using human induced pluripotent stem (iPS) cells-derived neural organoids. Cells were treated with rotenone as well as the controls at varying concentrations (0.3 μM, 1 μM, and 25 μM) for 48 hours. RNA was subsequently extracted, and RNA sequencing (RNA-seq) was performed to analyze gene expression profiles. The results revealed that rotenone exposure potentially suppresses critical ligand-receptor interactions involved in neural development. Network interaction analysis of KEGG signaling pathways highlighted the involvement of the focal adhesion pathway and the neuroactive ligand-receptor interaction pathway in the neurotoxic effects of rotenone. To evaluate the effects of rotenone exposure on the expression of genes related to neurodevelopment and synaptic transmission, undifferentiated hiPS cells were exposed to rotenone (0.3 μM, 1 μM, 25 μM) for 48 hours on the second day of differentiation. On day 4, total RNA was collected, RNA-seq data was obtained, and gene expression profiling analysis was performed.