Combined estrogenic effects of mycotoxin zearalenone with other phyto-, xeno-, and mycoestrogens on Tg(vtg1:mCherry) zebrafish embryos

Zearalenone (ZEN) is mycoestrogen that is produced by Fusarium fungi. Despite the increasing recognition that humans and wildlife are typically exposed to complex mixtures of endocrine-disrupting chemicals rather than individual compounds, the interactions between naturally occurring xenoestrogens and/or phytoestrogens remain poorly understood and mostly evaluated based on in vitro experiments. In the current study, the combined estrogenic effects of ZEN with phytoestrogens (daidzein and genistein), pesticide-related compounds (glyphosate and aminomethylphosphonic acid), plastic-derived xenoestrogens (bisphenol A and S), its own conjugated metabolites (ZEN-14- O -sulfate and ZEN-14- O -glucuronide), and other mycoestrogens (alternariol and alternariol-3- O -sulfate) were examined applying the Tg( vtg1 :mCherry) transgenic zebrafish embryo model. Genistein, glyphosate, and bisphenols markedly increased ZEN-induced estrogenicity, even at nanomolar and/or low micromolar levels where they did not show estrogenic impacts alone in the model used. However, ZEN-14- O -sulfate and alternariol-3- O -sulfate reduced the ZEN-induced response, showing their most dominant actions at nanomolar concentrations. Interestingly, ZEN-14- O -sulfate can also decrease the impact of 17β-estradiol while alternariol-3- O -sulfate enhanced it, suggesting complex modulatory ability of the latter metabolite. Response-additivity analysis identified significant supra-additivity with genistein (0.75 μM), bisphenol A (0.25 μM and 0.75 μM), and bisphenol S (0.75 μM); while sub-additivity was noticed with aminomethylphosphonic acid (0.25 μM) and alternariol-3- O -sulfate (all concentrations tested).