Transcriptome profile analysis reveals specific signatures of pollutants in Atlantic eels

Abstract

Identifying specific effects of contaminants in a multi-stress field context remain a challenge in ecotoxicology. In this context, ''omics'' technologies, by allowing the simultaneous measurement of numerous biological endpoints, could help unravel the in situ toxicity of contaminants. In this study, wild Atlantic eels were sampled in 8 sites presenting a broad contamination gradient in France and Canada. The global hepatic transcriptome of animals was determined by RNA-Seq. In parallel, the contamination level of fish to 8 metals and 25 organic pollutants was determined. Factor analysis for multiple testing was used to identify genes that are most likely to be related to a single factor. Among the variables analyzed, arsenic (As), cadmium (Cd), lindane (c-HCH) and the hepato-somatic index (HSI) were found to be the main factors affecting eel's transcriptome. Genes associated with As exposure were involved in the mechanisms that have been described during As vasculotoxicity in mammals. Genes correlated with Cd were involved in cell cycle and energy metabolism. For c-HCH, genes were involved in lipolysis and cell growth. Genes associated with HSI were involved in protein, lipid and iron metabolisms. Our study proposes specific gene signatures of pollutants and their impacts in fish exposed to multi-stress conditions.

Detecting the exposure to Cd and PCBs by means of a non-invasive transcriptomic approach in laboratory and wild contaminated European eels (Anguilla anguilla)

“…The gene rras2 encodes a protein that transduces growth inhibitory signals across the cell membrane. Such a result is in accordance with our previous work (Baillon et al 2015a). Genes involved in cell cycle arrest or in the inhibition of cell proliferation were upregulated in the liver of wild Cd-contaminated yellow eels.…”

“…In a previous study (Baillon et al 2015a), we used RNASeq technology on both the liver of European and American (Anguilla rostrata) eels. The main objective of that previous study was to discover without any a priori statistically confident Bcandidate genes' that are more likely related to contaminant exposure than to natural stressors.…”

Transcriptomic responses of the endangered freshwater mussel Margaritifera margaritifera to trace metal contamination in the Dronne River, France

“…In order to favor strong correlations, the R package FAMT (Causeur et al 2011) was used with a FDR value of 0.01. This approach proved its usefulness in previous ecotoxicology studies (Baillon et al 2015). The FDR was increased to 0.05 when comparing age classes due to the smaller number of individuals.…”

Gonadal transcriptome analysis of wild contaminated female European eels during artificial gonad maturation

“…Migrating female silver eels (Anguillla anguilla) were captured during their continental downstream migration in winter 2012-2013, in the Arcachon Bay in the Domaine de Certes salt marshes (southwest of France, 44°41 0 18 00 N 1°1 0 39 00 W) a site considered as ''clean'', and in the Gironde estuary (45°12 0 06.62 00 N 0°43 0 34.72 00 O), considered as highly contaminated (Baillon et al, 2015). The animals were transferred to the laboratory (Irstea experimental station), individually marked with pit-tags and randomly mixed in two separate swim tanks (salinity 30‰, natural seawater) thermostated at 15°C.…”

“…The aim of this study was to investigate the possible impacts of contaminants on gonad growth as well as the toxic mechanisms of contaminants on gonads during artificial maturation of European female silver eels by means of a transcriptomic approach using a DNA microarray comprising 1000 candidate gene targets (Baillon et al, 2015).…”