Project description:Silver nanomaterials (AgNMs) are broadly used in many products and also rate among the most studied nanoscaled materials. Their ecotoxicological impact in soil invertebrates has been covered, mostly using standard testing, where endpoints like survival and reproduction are assessed. The underlying molecular mechanisms have been assessed to a much less extent. Hence, we here assessed differentially expressed proteins (DEPs) and metabolites (DEMs) by high-throughput (HTP) techniques (HPLC-MS/MS with tandem mass tags for proteome analysis, as well as reversed-phase (RP)- or hydrophilic interaction liquid chromatography (HILIC) with mass spectrometric detection for metabolome analysis. The standard soil model Enchytraeus crypticus was exposed to Ag NM300K and soluble AgNO3, at the reproduction EC20 and EC50, in a time series of 0, 7, and 14 days. The impact was clearly larger after 14 days. Ag NM300K caused more upregulated DEPs/DEMs, and more so at the EC20, compared to the EC50, whereas AgNO3 caused a dose response increase of DEPs/DEMs. Similar pathways were activated, although often via opposite regulation (up vs down) of DEPs hence dissimilar mechanisms underlie the apical impact. Affected pathways include e.g. energy metabolism transport proteins, detoxifying enzymes, histidine (e.g. neurotransmission by gamma-aminobutyric acid (GABA)) and lipid metabolism. Uniquely affected by AgNO3 were catalase, malate dehydrogenase and ATP-citrate synthase, and by Ag NM300K were heat shock proteins (HSP70) and ferritin. The gene expression-based data in Adverse Outcome Pathway (AOP) was confirmed and additional key events were added. Evidences support that toxicity of Ag NM increases in longer-term exposure.
