Bioaccumulation and molecular effects of carbamazepine and methylmercury co-exposure in males of Dreissena polymorpha

• Published in: The Science of the total environment 2023-11, Vol.897, p.165379-165379, Article 165379
• Main Authors: Baratange, Clément, Baali, Hugo, Gaillet, Véronique, Bonnard, Isabelle, Delahaut, Laurence, Gaillard, Jean-Charles, Grandjean, Dominique, Sayen, Stéphanie, Gallorini, Andrea, Le Bris, Nathalie, Renault, David, Breider, Florian, Loizeau, Jean-Luc, Armengaud, Jean, Cosio, Claudia
• Format: Article
• Language: English
• Subjects: Bivalve; Environmental Sciences; Freshwater; Multi-omics; Toxicity pathways
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2023.165379

Dreissena polymorpha is a bivalve promising for biomonitoring in freshwater ecosystems thanks to its abundance and high filtration activity allowing rapid uptake of toxicants and identification of their negative effects. Nonetheless, we still lack knowledge on its molecular responses to stress under realistic scenario, e.g. multi-contamination. Carbamazepine (CBZ) and Hg are ubiquitous pollutants sharing molecular toxicity pathways, e.g. oxidative stress. A previous study in zebra mussels showed their co-exposure to cause more alterations than single exposures, but molecular toxicity pathways remained unidentified. D. polymorpha was exposed 24 h (T24) and 72 h (T72) to CBZ (6.1 ± 0.1 μg L−1), MeHg (430 ± 10 ng L−1) and the co-exposure (6.1 ± 0.1 μg L−1CBZ and 500 ± 10 ng L−1 MeHg) at concentrations representative of polluted areas (~10× EQS). RedOx system at the gene and enzyme level, the proteome and the metabolome were compared. The co-exposure resulted in 108 differential abundant proteins (DAPs), as well as 9 and 10 modulated metabolites at T24 and T72, respectively. The co-exposure specifically modulated DAPs and metabolites involved in neurotransmission, e.g. dopaminergic synapse and GABA. CBZ specifically modulated 46 DAPs involved in calcium signaling pathways and 7 amino acids at T24. MeHg specifically modulated 55 DAPs involved in the cytoskeleton remodeling and hypoxia-induced factor 1 pathway, without altering the metabolome. Single and co-exposures commonly modulated proteins and metabolites involved in energy and amino acid metabolisms, response to stress and development. Concomitantly, lipid peroxidation and antioxidant activities were unchanged, supporting that D. polymorpha tolerated experimental conditions. The co-exposure was confirmed to cause more alterations than single exposures. This was attributed to the combined toxicity of CBZ and MeHg. Altogether, this study underlined the necessity to better characterize molecular toxicity pathways of multi-contamination that are not predictable on responses to single exposures, to better anticipate adverse effects in biota and improve risk assessment. [Display omitted] •Carbamazepine (CBZ), methylmercury (MeHg) and the co-exposure were studied in Dreissena polymorpha.•Proteins and metabolites involved in amino acid and energy metabolisms, response to stress and cellular development were altered.•CBZ, MeHg & the co-exposure modulated proteins involved in the Ca2+ pathway, cytoskeleton and neuro