Differentially transcriptional regulation on cell cycle pathway by silver nanoparticles from ionic silver in larval...

Silver nanoparticles (AgNPs) have a strong antibacterial activity and the relevant modes of actions have regarded as direct or indirect causes of toxicity observed in the environment. In this study, the transcriptomic profiles in larval zebrafish (Danio rerio) exposed to AgNPs (about 50 nm in size) and AgNO₃ as a comparative ionic silver were investigated and analyzed using differential expressed gene (DEG), Gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) pathway analyses. Results indicated that underlying molecular mechanisms are different each other. Interestingly, the global gene expression profiling showed that cell cycle pathway is affected by both AgNPs and dissolved Ag⁺, however its regulation pattern was opposite each other. To the best of our knowledge, the up-regulation of cell cycle pathway by AgNPs and down-regulation by Ag⁺ is the first reporting and suggests the distinguished toxicological perspective from a well-known hypothesis that Ag⁺ mainly regulates the cell cycle. This study provides novel insights onto the genotoxicological mechanisms of AgNPs.