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

Abstract

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.

Nanomaterials and Annelid Immunity: A Comparative Survey to Reveal the Common Stress and Defense Responses of Two Sentinel Species to Nanomaterials in the Environment

“…One of the limited studies on this topic investigated the transcriptomic changes of AgNP exposure in the earthworm E. fetida [ 78 ]. It brought interesting results of upregulation of genes coding for endocytosis and functions of cell cilia.…”

Is a Water Content of 60% Maximum Water Holding Capacity Suitable for Folsomia candida Reproduction Tests? A Study with Silver Nanoparticles and AgNO3

“…Currently the environmental concentrations are still very low, for example, 20–350 ng·kg −1 [ 3 ] in Denmark, but are expected to increase. Numerous studies have examined the toxicity of AgNP to soil invertebrates and detected negative effects on reproduction, survival, biomass, and gene expression (e.g., [ 4 , 5 , 6 , 7 , 8 , 9 ]). Species-, particle-, and concentration-dependent effects were found.…”

Collembola Reproduction Decreases with Aging of Silver Nanoparticles in a Sewage Sludge-Treated Soil

“…The focus in ecotoxicological testing of AgNP in soil has, thus far, been more on microorganisms (Schlich et al, 2013b;Engelke et al, 2014;McKee and Filser, 2016), earthworms (Heckmann et al, 2011;Shoults-Wilson et al, 2011a;Schlich et al, 2013a;van der Ploeg et al, 2014;Novo et al, 2015), enchytraeids (Gomes et al, 2013(Gomes et al, , 2015Ribeiro et al, 2015;Bicho et al, 2016) and nematodes (Roh et al, 2009;Meyer et al, 2010). Collembola have received less attention.…”