Transcriptomic insight into cadmium-induced neurotoxicity in embryonic neural stem/progenitor cells

Cadmium exposure has raised great public concern. Extensive studies have revealed the neurotoxic effects of cadmium exposure during brain development. However, more evidence is still needed to reach a consistent conclusion and uncover the underlying mechanisms. Here, we used primary mouse embryonic neural stem/progenitor cells (NSPCs) as a cell model and exposed the cells to 0, 1, 2 or 4 μM cadmium. High-throughput mRNA-seq technology was used to explore the global transcriptome changes in NSPCs after exposure to 2 μM cadmium. We found that cadmium exposure remarkably influenced the expression of genes involved in cell growth, proliferation, cell cycle and survival. Pathway-Act-Network analysis revealed that these altered genes were targeted to the P53, PI3K-AKT, MAPK, calcium, and NF-kappa B signaling pathways. In vitro experiments using cultured NSPCs verified that cadmium exposure reduced cell viability, proliferation, neurosphere formation and caused cell cycle arrest at low concentrations (≤ 2 μM), while induced cell apoptosis at high concentrations (≥ 4 μM). Real-time PCR results confirmed the concentration-dependent effects of cadmium exposure on the expression of critical genes in the above signaling pathways. Together, our results provide transcriptomic insight into cadmium-induced developmental neurotoxic effects and the underlying mechanisms.