Multiscale approaches to characterize Cellular Interaction, Trophic transfer and TOXIC impacts of metallic Nanoparticles in aquatic organisms

Informations

Funding country

France

Acronym

CITTOXIC-Nano

URL

-

Start date

1/1/2014

End date

-

Budget

440,000 EUR

Fundings

Abstract

This interdisciplinary project aims to study for the first time the behaviour, the interactive capacity, the internalization, the toxic impact and the trophic transfer of functionalized metallic nanoparticles (NPs), considered as models of NPs potentially encountered in natural ecosystems, in aquatic organisms. Besides their broad use in biotech industries, their physical and chemical specific properties present assets making them trackable in laboratory experiments in order to evaluate the nature of interactions and possible toxic impacts in the different biological compartments, and to forecast environmental consequences along trophic webs in freshwaters. Therefore different strategies at different levels of organization (molecular, cellular, organism and trophic chain) are proposed to study the biological impact of gold (Au) and silver (Ag) NPs in various freshwater organisms (periphytic diatoms, bivalve molluscs and fish). Developments in terms of NPs synthesis and characterization will be first conducted to propose different types of NPs in size, shape, coating and charge, adapted to the different proposed experiments. New molecular targets of the transcriptome of organisms studied will be developed, notably on diatoms and bivalves to extend the possibilities to understand the mechanisms of action of NPs towards aquatic organisms. The NPs interactions with different cell types (diatoms, bivalve hemocytes and eel hepatocytes) will be studied in order to quantify the functional groups implied in NPs fixation and also to characterize the mechanisms of internalization of these particles by cells in culture. At the organism level, the bioaccumulation of NPs will be quantified by metals analysis in the different organs, and the tissue and intra-cellular localization of the particles will be determined by correlative microscopy (optical, confocal, fluorescence and transmission electron) and 2D and 3D X-ray based imaging techniques. Toxic impacts generated by these particles will be also assessed by histology analyses, quantification of proteins implied in the metals detoxification, gestion of oxidative stress, and quantitative analysis of gene expression implied in different functions (oxidative stress, detoxification, mitochondrial metabolism, apoptosis, genotoxicity). Trophic transfer of metallic NPs between periphytic diatoms and organisms such as fish will be then studied, with two to three levels of trophic transfer. The final consumer of this chain will be the carnivore European eel Anguilla anguilla on which in vivo ingestion of AuNPs labelled by a fluorescent probe will be studied by fluorescence imaging and toxic impacts by the use of a DNA microarray. The construction of this microarray of around 1000 genes is currently developed in our laboratory in another project (International ANR IMMORTEEL France/Québec), and it will allow us to characterize the gene expression pattern specific to NP exposure and to precisely define the mechanisms of toxicity involved in fish in relation with the accurate location and quantification of NPs at the tissue and cellular levels. Finally, considering the incorporation of NPs into consumer products and domestic sources accounting for a significant dispersion of NPs into ecosystems, the Human Ecology approach, especially the family ecology approach, will aim to identify which consumer products are concerned, to clarify their use and to assess NPs outputs, in order to link the use of consumer products and the ecotoxicological impacts in aquatic ecosystems. All these different approaches will help us to realize a complete diagnosis of the attacks and impacts which might be expected in aquatic organisms and along the trophic web, after a contamination by Au or AgNPs.