Different routes, same pathways: Molecular mechanisms under silver ion and nanoparticle exposures in the soil sentinel Eisenia fetida

• Published in: Environmental pollution (1987) Vol. 205; pp. 385 - 393
• Main Authors: Novo, Marta, Lahive, Elma, Díez-Ortiz, María, Matzke, Marianne, Morgan, Andrew J., Spurgeon, David J., Svendsen, Claus, Kille, Peter
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-10-2015
• Subjects: Animals; Cellular; Cryptic lineage; Eisenia fetida; Electron Transport Complex IV - genetics; Electron Transport Complex IV - metabolism; Exposure; Gene Expression Regulation; Histones; Ions; Metal Nanoparticles - toxicity; Molecular Sequence Data; Nanoparticles; Nanostructure; Oligochaeta - drug effects; Oligochaeta - genetics; Oligochaeta - metabolism; Pathways; Phylogeny; Protein metabolism; Sequence Analysis, DNA; Silver; Silver - toxicity; Soil (material); Soil Pollutants - toxicity; Soil sentinel; Toxicokinetics; Nanoparticles; Toxicokinetics; Silver; Ions; Soil sentinel; Cryptic lineage
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2015.07.010

Use of nanotechnology products is increasing; with silver (Ag) nanoparticles particularly widely used. A key uncertainty surrounding the risk assessment of AgNPs is whether their effects are driven through the same mechanism of action that underlies the toxic effects of Ag ions. We present the first full transcriptome study of the effects of Ag ions and NPs in an ecotoxicological model soil invertebrate, the earthworm Eisenia fetida. Gene expression analyses indicated similar mechanisms for both silver forms with toxicity being exerted through pathways related to ribosome function, sugar and protein metabolism, molecular stress, disruption of energy production and histones. The main difference seen between Ag ions and NPs was associated with potential toxicokinetic effects related to cellular internalisation and communication, with pathways related to endocytosis and cilia being significantly enriched. These results point to a common final toxicodynamic response, but initial internalisation driven by different exposure routes and toxicokinetic mechanisms.
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•Molecular effects underlying Ag ions and NPs exposure were studied in Eisenia fetida.•Full transcriptomic study of a genetically characterised lineage.•NPs and ions presented a similar toxicodynamic response.•Internalisation of the two Ag forms by different toxicokinetic mechanisms.
Transcriptomic analyses after exposure of earthworms to silver NPs or ions showed a final common toxicodynamic response, but internalisation by different toxicokinetic mechanisms.