Biotransformation of the Mycotoxin Zearalenone to its Metabolites Hydrolyzed Zearalenone (HZEN) and Decarboxylated Hydrolyzed Zearalenone (DHZEN) Diminishes its Estrogenicity In Vitro and In Vivo

• Published in: Toxins 2019-08, Vol.11 (8), p.481
• Main Authors: Fruhauf, Sebastian, Novak, Barbara, Nagl, Veronika, Hackl, Matthias, Hartinger, Doris, Rainer, Valentina, Labudová, Silvia, Adam, Gerhard, Aleschko, Markus, Moll, Wulf-Dieter, Thamhesl, Michaela, Grenier, Bertrand
• Format: Article
• Language: English
• Subjects: Animals; Bioassays; Biotransformation; Breast cancer; Cancer therapies; Cell culture; Cell growth; Cell proliferation; Enzymes; estrogen receptor; estrogen response element; Estrogenic activity; Estrogens; Feed additives; Feeds; Gene expression; Hogs; Livestock; Metabolites; Microorganisms; MicroRNAs; miRNA; Morphology; Mycotoxins; Reaction products; Reporter gene; Reproductive system; Ribonucleic acid; RNA; Swine; Transcription; Uterus; Vulva; Xenoestrogens; Yeasts; Zearalenone
• ISSN: 2072-6651; 2072-6651
• DOI: 10.3390/toxins11080481

Zearalenone (ZEN)-degrading enzymes are a promising strategy to counteract the negative effects of this mycotoxin in livestock. The reaction products of such enzymes need to be thoroughly characterized before technological application as a feed additive can be envisaged. Here, we evaluated the estrogenic activity of the metabolites hydrolyzed zearalenone (HZEN) and decarboxylated hydrolyzed zearalenone (DHZEN) formed by hydrolysis of ZEN by the zearalenone-lactonase Zhd101p. ZEN, HZEN, and DHZEN were tested in two in vitro models, the MCF-7 cell proliferation assay (0.01-500 nM) and an estrogen-sensitive yeast bioassay (1-10,000 nM). In addition, we compared the impact of dietary ZEN (4.58 mg/kg) and equimolar dietary concentrations of HZEN and DHZEN on reproductive tract morphology as well as uterine mRNA and microRNA expression in female piglets (n = 6, four weeks exposure). While ZEN increased cell proliferation and reporter gene transcription, neither HZEN nor DHZEN elicited an estrogenic response, suggesting that these metabolites are at least 50-10,000 times less estrogenic than ZEN . In piglets, HZEN and DHZEN did not increase vulva size or uterus weight. Moreover, RNA transcripts altered upon ZEN treatment (EBAG9, miR-135a-5p, miR-187-3p and miR-204-5p) were unaffected by HZEN and DHZEN. Our study shows that both metabolites exhibit markedly reduced estrogenicity in vitro and , and thus provides an important basis for further evaluation of ZEN-degrading enzymes.