Integrative multi-omic analysis reveals epigenetic and neurotransmitter signaling disruption induced by tributyltin in zebrafish eleutheroembryos.

Environmental exposure to endocrine disruptors such as Tributyltin (TBT) has been established as a serious threat causing neurological impairment, reproduction dysfunction and lipid dysregulation. However, the molecular mechanisms underlying TBT-induced toxicity, particularly its capacity to disrupt epigenetic programming during critical developmental windows, remain poorly understood. State-of-the-art multi-omic approaches have emerged to consider the complexity of the different omic systems, crucial for a better characterization of the mechanisms of action of pollutants. In the present study, a novel multi-omic analysis integrating epigenomics, transcriptomics, and metabolomics was conducted on zebrafish eleutheroembryos exposed from 2 to 5 days post-fertilization to two non-toxic TBT concentrations (3 and 30 nM). To capture not only the toxic mechanisms but also multifaceted molecular interactions from gene to phenotype, multi-omics results were complemented by behavioural and neurotransmitter content analyses at the end of the exposures and after a 3-day clearance period. TBT induced the appearance of 5 280 differentially methylated regions, with significant enrichment in intergenic, CpG islands, and promoter regions. Our results also revealed that altered differentially methylated regions were involved in key biological processes, including nervous system development, synaptic signaling, and muscle structure development. Multi-omic analysis identified significant alterations in neurotransmitter signaling pathways, which were then confirmed through neurotransmitter content analysis. TBT also affected responses at the organismal level, particularly impairing cognitive performance. Altogether, the integration of multi-omic strategies demonstrated the potential to revolutionize the future of toxicology by enhancing the understanding of environmental pollutant effects, paving the way for more refined risk assessment and regulatory frameworks.