Toxicogenomics of iron oxide nanoparticles in the nematode C. elegans.

We present a mechanistic study of the effect of iron oxide nanoparticles (SPIONs) in Caenorhabditis elegans combining a genome-wide analysis with the investigation of specific molecular markers frequently linked to nanotoxicity. The effects of two different coatings were explored: citrate, an anionic stabilizer, and bovine serum albumin, as a pre-formed protein corona. The transcriptomic study identified differentially expressed genes following an exposure to SPIONs. The expression of genes involved in oxidative stress, metal detoxification response, endocytosis, intestinal integrity and iron homeostasis was quantitatively evaluated. The role of oxidative stress was confirmed by gene expression analysis and by synchrotron Fourier Transform infrared microscopy based on the higher tissue oxidation of NP-treated animals. The observed transcriptional modulation of key signaling pathways such as MAPK and Wnt suggests that SPIONs might be endocytosed by clathrin-mediated processes, a putative mechanism of nanotoxicity which deserves further mechanistic investigations.