Silver Nanoparticles Suppress Retinoic Acid-Induced Neuronal Differentiation in Human-Derived Neuroblastoma SH-SY5Y Cells

Nanoparticles are being used in an increasing number of applications in a wide range of fields; however, these particles can migrate to the brain, raising concerns over their potential as risk factors of neurodevelopment disorders. Here, we examined the effects of silver nanoparticles with a diameter of 10 nm (nAg10) on neural differentiation in human-derived neuro-blastoma SH-SY5Y cells. SH-SY5Y cells treated with retinoic acid undergo neuronal differentiation characterized by increased expression of brain-derived neurotrophic factor (BDNF); however, co-treatment of these cells with retinoic acid (RA) and nAg10 significantly mitigated this RA-induced BDNF expression. RA-induced neurite outgrowth and extracellular secretion of dopamine were significantly suppressed by nAg10 in a concentration-dependent manner. Reactive oxygen species (ROS) production was enhanced in cells co-treated with RA and nAg10, and the expression level of BDNF was restored by co-treatment with nAg10 and an ROS inhibitor (N-acetylcysteine). nAg10-induced mitochondrial ROS production and decreased mitochondrial fusion-related gene expression. In summary, nAg10 suppressed retinoic acid-induced neuronal differentiation in SH-SY5Y cells via the oxidative stress pathway, induced mitochondrial ROS production, and decreased mitochondrial fusion-related gene expression.