Transcriptomic analyses in brains of exposed F0 zebrafish and their unexposed F2 offspring after exposure to a mixture of PCBs and PBDEs

Polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) are persistent organic pollutants still present in aquatic environments despite their total or partial ban. Previously, we observed that an environmentally realistic mixture of these compounds affects energy balance, growth, and reproduction in exposed zebrafish (F0), and behavior in their unexposed offspring (F1-F4). In the present work, we performed lipidomic and transcriptomic analyses on brains of zebrafish (F0-F2) from exposed and control lineages to identify molecular changes that could explain the observed phenotypes. The use of both technologies highlighted that F0 zebrafish displayed impaired mitochondrial function and lipid metabolism dysregulation (depletion in triacylglycerols and phospholipids) which can explain disruption of energy homeostasis. A subset of the dysregulated biological pathways (Gene Ontology and Reactome databases) related to energetic metabolism and neurotransmission were inherited in F2. In addition, there were increasing effects on epigenetic pathways from the F0 to the F2 generation. Altogether, we show that the effects of an environmental exposure to PCBs and PBDEs on energetic metabolism as well as neurotransmission extend over 2 generations of zebrafish, possibly due to transgenerational epigenetic inheritance. Overall design: RNA-sequencing was performed on F0 male fish from the F0 generation (6 replicates treatment, 6 replicates control), on F2 female fish (4 replicates treatment, 4 replicates control) and on F2 male fish (2 replicates treatment, 2 replicates control).