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

Abstract

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 vitro. 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 in vivo, and thus provides an important basis for further evaluation of ZEN-degrading enzymes.

Detoxification of Mycotoxins through Biotransformation

“…In addition, ZEN (33) was converted to hydrolyzed ZEN (155) through hydrolysis, and then to decarboxylated hydrolyzed ZEN (156) through spontaneous decarboxylation by Bacillus pumilus ( Figure S84) [122]. Similar biotransformation of ZEN (33) was also observed by using a lactonase named ZHD101 from Clonostachys rosea [123,124].…”

“…T-2 toxin (31) HT-2 toxin (122) Eubacterium BBSH 797 (bacterium) [86] HT-2 toxin (122),15-acetyl-tetraol (123),T-2 tetraol (124) Liver and intestines of rats [102] Neosolaniol ( Bacillus amyloliquefaciens (bacterium) [98] Lactone-opened ochratoxin A (OP-OTA, 120) Rats [99] Ochratoxin C (OTC) = Ochratoxin A ethyl ester (121) Ochratoxin A (OTA, 21)…”

“…Bacillus pumilus (bacterium) [122] Hydrolysis, spontaneous decarboxylation Lactonase [123] Hydrolysis, spontaneous decarboxylation Lactonase [124] Iso-DOM-3-GlcA (95) and iso-DOM-8-GlcA (96) Isomerization and glucuronization RLM [71] Fomannoxin (40) Fomannoxin acid (59) and fomannoxin acid β-glucoside (145) Oxidation and glycosylation Cell cultures of Pinus sylvestris [44] Fumonisin B1 (115) Hydrolyzed fumonisin B1 = Aminopentol 1 (AP1, 116) and 2-keto AP1 (132)…”

Zearalenone Removal from Corn Oil by an Enzymatic Strategy

“…Subsequently, the lactonohydrolase ZHD101 from C. rosea catalyzing this reaction was characterized and its encoding gene was found and cloned [23]. Further, the reaction mechanism was also unveiled [24] and the structures of degradation products were confirmed as well, which were followed by evaluation on the toxicity of these products ( Figure 1) including hydrolyzed ZEN (HZEN) and decarboxylated hydrolyzed ZEN (DHZEN) [25].…”

Novel Approaches to Minimizing Mycotoxin Contamination

“…With respect to enzymatic detoxification, Alberts et al [10] developed an innovative method using the commercial fumonisin esterase FumD to reduce fumonisin B in whole maize, resulting in the formation of the hydrolyzed breakdown product, HFB1, associated with the aqueous phase to be discarded. Fruhauf et al [11] concluded that the cleavage of ZEA by the zearalenone-lactonase Zhd101p reduces its estrogenicity in piglets, providing an important basis for the further evaluation of ZEA-degrading enzymes.…”