Transfer and Transcriptomic Profiling in Liver and Brain of European Eels Anguilla anguilla After Diet‐borne Exposure to Gold Nanoparticles

Nanometric revolution is underway, promising technical innovations in a wide range of applications, leading to a potential boost in environmental discharges. Nanoparticle propensity to be transferred throughout trophic chains and to generate toxicity was mainly assessed in primary consumers while a lack of knowledge for higher trophic levels persists. This study focused on a predatory fish, the European eel Anguilla anguilla exposed to gold nanoparticles (AuNP, 10 nm, PEG-coated) for 21 days at three concentration levels in food: 0 (NP0), 1 (NP1) and 10 (NP10) mg Au.kg-1 . Transfer was assessed by gold quantification in eel tissues and transcriptomic responses in the liver and brain were revealed by a high-throughput RNA-sequencing approach. Eels fed at NP10 presented an erratic feeding behaviour while gold quantification only indicated transfer to intestine and kidney of NP1 exposed eels. RNA-Sequencing was performed in NP0 and NP1 eels. A total of 258 genes and 156 genes were significantly differentially transcribed in response to AuNP trophic exposure in the liver and brain, respectively. Enrichment analysis highlighted modifications in the immune system-related processes in the liver. In addition, results pointed out a shared response of both organs regarding 13 genes, most of them being involved in immune functions. This finding may shed light into the mode of action and toxicity of AuNP in fish. This article is protected by copyright. All rights reserved.