Synergistic disruption of brain metabolism and inflammatory signaling in adult zebrafish by co-exposure to alternariol monomethyl ether and titanium dioxide nanoparticles at physiologically relevant levels.

The combined health risks of mycotoxins and nanoparticles (NPs) remain poorly understood, particularly at physiologically relevant concentrations. Herein, we investigated the neurotoxic effects of 21-day exposure to alternariol monomethyl ether (AME, 0.2 nM) and titanium dioxide (TiO2) NPs (4.2 μg/mL), alone and in combination, in 5-month-old adult male zebrafish. While individual exposures caused minimal histopathological alterations and modest increase in swimming distance, metabolomic profiling revealed striking synergistic effects, that co-exposure altered 33 brain metabolites (vs. 11 by AME alone), predominantly affecting energy metabolism pathways (purine/pyrimidine metabolism, starch/sucrose conversion) and inflammatory signaling (arachidonic acid cascade). Specifically, combined treatment upregulated key glycolytic intermediates (glucose 1,6-bisphosphate, glucose-6-phosphate), pro-inflammatory PGE2, and nucleotide metabolites (ADP, GMP) while depleting deoxyribonucleotides (dAMP, dCMP). RT-PCR data confirmed pathway-level dysregulation, with co-exposure inducing up-regulation of prostaglandin synthases (ptgs1, ptgs2a), pro-inflammatory cytokines (tnf-α, ilβ), and rate-limiting enzymes in glycolysis (pfk) and pentose phosphate pathway (g6pd). Notably, despite AME alone increasing oxidative stress markers (oxidized glutathione), coordinated antioxidant responses (nrf2, sod2, gpx1a) were only triggered in co-exposed group. Our findings demonstrate that TiO2 NPs potentiate AME-induced metabolic rewiring and neuroinflammation at physiologically relevant levels, underscoring the necessity to reassess combined toxicities of emerging contaminants through pathway-based approaches.