Estrogenic activity of zearalenone, α-zearalenol and β-zearalenol assessed using the E-screen assay in MCF-7 cells

A diverse Fusarium community is responsible for contamination of rice with a variety of Fusarium toxins

Rice plays an important role in the daily diet in China and therefore its quality and safety have been of great concern. However, few systematic studies have investigated Fusarium community and toxins in rice grains. Here, we collected 1381 rice samples from Jiangsu Province in eastern China and found a higher frequency of zearalenone (ZEN), deoxynivalenol (DON), fumonisins (FBs), and beauvericin (BEA). The positive samples were individually contaminated with a minimum of one and a maximum of ten toxins. Fusarium was isolated and identified as the major fungus, which exhibited temporal and geographical distribution. The most prevalent species complexes within this genus were Fusarium incarnatum-equiseti species complex (FIESC), Fusarium fujikuroi species complex (FFSC), and Fusarium sambucinum species complex (FSAMSC). Nevertheless, the amplicon sequence analysis revealed a low relative abundance of Fusarium in the rice panicles, and the fungal community exhibited an irregular change along with the symptom's emergence. In vitro toxigenic profiles of Fusarium strains showed significant complexity and specificity depending on the type and content. FIESC strains were non-pathogenic to wheat heads and weakly pathogenic to maize ears, respectively, accumulating lower amounts of toxins than F. asiaticum and F. fujikuroi. There was no significant variation in the ability to cause panicle blight in rice among the various species tested. Our study provides detailed information about the contamination of Fusarium toxins and community in rice after harvest. This information is valuable for understanding the relationship between Fusarium and rice and for developing effective control strategies.

Estrogenic, androgenic, and genotoxic activities of zearalenone and deoxynivalenol in in vitro bioassays including exogenous metabolic activation

Zearalenone (ZEN) and deoxynivalenol (DON) and their derivatives are well-known mycotoxins, which can occur not only in crops but also in water bodies, including drinking water sources. In vitro bioassays can be used to detect biological effects of hazardous compounds in water. To this, when studying biological effects and toxicity in vitro, metabolism is important to consider. In this study, ZEN, α-zearalenol (α-ZEL), DON, 3-acetyl DON, and 15-acetyl DON were evaluated in vitro for hormone receptor-mediated effects (estrogen receptor [ER] and androgen receptor [AR]) and genotoxicity (micronucleus assay) in the presence of an exogenous metabolic activation system (MAS). The ER bioassay proved to be a highly sensitive method to detect low concentrations of the ZEN compounds (EC10 values of 31.4 pM for ZEN, 3.59 pM for α-ZEL) in aqueous solutions. In the presence of the MAS, reduced estrogenic effects were observed for both ZEN compounds (EC10 values of 6.47 × 103 pM for ZEN, 1.55 × 102 pM for α-ZEL). Of the DON compounds, only 3-acetyl DON was estrogenic (EC10 of 0.31 µM), and the effect was removed in the presence of the MAS. Anti-androgenic effects of the ZEN compounds and androgenic effects of the DON compounds were detected in the micromolar range. No induction of genotoxicity was detected for ZEN or DON in the presence of the MAS. Our study highlighted that inclusion of exogenous MAS is a useful tool to detect biological effects of metabolites in in vitro bioassays.

Cell proliferation assay for determination of estrogenic components in food: a systematic review

Due to the widespread use and environmental pollution of estrogenic chemicals, the need for screening tests to detect these compounds is felt more than ever. These compounds lead to cell proliferation. Therefore, studies used cell proliferation to evaluate estrogenic compounds was studied in this systematic review. This systematic review was performed with the keywords; DNA proliferation, cell proliferation, estrogenic component, estrogen, food, bioassay, screening, and detection. After initial screening and full text quality assessment, 16 manuscripts were selected and data were extracted. Four cell lines, MCF-7, MDA-MB-231, Ishikawa, and T47D cells were used in the studies. MCF-7 was more sensitive to estrogenic compounds than other lines. Most of the samples studied were plant compounds and mycotoxins and substances that migrate from packaging to food. This screening test is valid and has similar results as others.

Endocrine-disrupting compounds and metabolomic reprogramming in breast cancer

Endocrine-disrupting chemicals pose a growing threat to human health through their increasing presence in the environment and their potential interactions with the mammalian endocrine systems. Due to their structural similarity to hormones like estrogen, these chemicals can interfere with endocrine signaling, leading to many deleterious effects. Exposure to estrogenic endocrine-disrupting compounds (EDC) is a suggested risk factor for the development of breast cancer, one of the most frequently diagnosed cancers in women. However, the mechanisms through which EDCs contribute to breast cancer development remain elusive. To rapidly proliferate, cancer cells undertake distinct metabolic programs to utilize existing nutrients in the tumor microenvironment and synthesize macromolecules de novo. EDCs are known to dysregulate cell signaling pathways related to cellular metabolism, which may be an important mechanism through which they exert their cancer-promoting effects. These altered pathways can be studied via metabolomic analysis, a new advancement in -omics technologies that can interrogate molecular pathways that favor cancer development and progression. This review will summarize recent discoveries regarding EDCs and the metabolic reprogramming that they may induce to facilitate the development of breast cancer.

Relationship Between Mycotoxin Production and Gene Expression in Fusarium graminearum Species Complex Strains Under Various Environmental Conditions

The Fusarium graminearum species complex (FGSC) can produce various mycotoxins and is a major concern for food quantity and quality worldwide. In this study, we determined the effects of water activity (a_w), temperature, incubation time and their interactions on mycotoxin accumulation and the expression levels of biosynthetic genes in FGSC strains from maize samples in China. The highest deoxynivalenol (DON), 3-acetyldeoxynivalenol(3ADON) and 15-acetyldeoxynivalenol (15ADON) levels of the F. boothii and F. graminearum strains were observed at 0.98 a_w/30 °C or 0.99 a_w/25 °C. F. asiaticum and F. meridionale reached maximum nivalenol (NIV) and 4-acetylnivalenol (4ANIV) contents at 0.99 a_w and 30 °C. With the extension of the incubation time, the concentrations of DON and NIV gradually increased, while those of their derivatives decreased. F. boothii, F. meridionale and one F. asiaticum strain had the highest zearalenone (ZEN) values at 0.95 a_w and 25 °C, while the optimum conditions for the other F. asiaticum strain and F. graminearum were 0.99 a_w and 30 °C. Four genes associated with trichothecene and zearalenone synthesis were significantly induced under higher water stress in the early stage of production. The results indicated independence of mycotoxin production and gene expression, as maximum amounts of these toxic metabolites were observed at higher a_w in most cases. This study provides useful information for the monitoring and prevention of such toxins entering the maize production chain.

Whole-genome sequencing and phylogenomic analyses of a novel zearalenone-degrading Bacillus subtilis B72

Bacillus strain B72 was previously isolated as a novel zearalenone (ZEN) degradation strain from the oil field soil in Xinjiang, China. The genome of B72 was sequenced with a 400 bp paired-end using the Illumina HiSeq X Ten platform. De novo genome assembly was performed using SOAPdenovo2 assemblers. Phylogenetic analysis using 16S rRNA gene sequencing demonstrated that B72 is closely related to the novel Bacillus subtilis (B. subtilis) strain DSM 10. A phylogenetic tree based on 31 housekeeping genes, constructed with 19 strains closest at the species level, showed that B72 was closely related to B. subtilis 168, B. licheniformis PT-9, and B. tequilensis KCTC 13622. Detailed phylogenomic analysis using average nucleotide identity (ANI) and genome-to-genome distance calculator (GGDC) demonstrated that B72 might be classified as a novel B. subtilis strain. Our study demonstrated that B72 could degrade 100% of ZEN in minimal medium after 8 h of incubation, which makes it the fastest degrading strain to date. Moreover, we confirmed that ZEN degradation by B72 might involve degrading enzymes produced during the initial period of bacterial growth. Subsequently, functional genome annotation revealed that the laccase-encoding genes yfiH (gene 1743) and cotA (gene 2671) might be related to ZEN degradation in B72. The genome sequence of B. subtilis B72 reported here will provide a reference for genomic research on ZEN degradation in the field of food and feed.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03517-y.

Cytoprotective, Antiproliferative, and Anti-Oxidant Potential of the Hydroethanolic Extract of Fridericia chica Leaves on Human Cancer Cell Lines Exposed to α- and β-Zearalenol

Fridericia chica (Bignoniaceae) is a Colombian Caribbean plant with numerous health benefits, including properties such as wound healing, immune system stimulation, and antioxidant capacity, among others. Mycotoxins alpha-zearalenol (α-ZEL) and beta-zearalenol (β-ZEL) are phase I metabolites of zearalenone, a natural product involved in endocrine disruption and cell proliferation processes. This study aimed to investigate the cytotoxic potential of the hydroethanolic extract of F. chica leaves (HEFc) and determine their protective effects against proliferation induced by α-ZEL and β-ZEL on human hepatoma HepG2, lung cancer Calu-1, and primary normal human epidermal keratinocytes, neonatal (HEKn). The cytotoxicity of HEFc was measured in a range from 4 to 1000 µg/mL and from 0.4 to 100 μM for both α-ZEL and β-ZEL. Cell production of intracellular ROS was monitored using the H2-DCFDA probe. The cells exposed to HEFc presented IC50 of 128, 249, and 602 µg/mL for the HepG2, Calu-1, and HEKn cells, respectively. A greater selectivity was seen in HepG2 cells [selectivity index (SI) = 3.5] than in Calu-1 cells (SI = 2.4). Cells treated with mycotoxins remained viable during the first day, and cell proliferation increased at low tested concentrations (0.4-6.3 µM) in all three cell lines. However, after 48 h treatment, cells exposed to 50 and 100 µM of α-ZEL and β-ZEL displayed decreased viability. HEFc at 16 µg/mL was able to give some protection against cytotoxicity induced by high concentrations of β-ZEL in HepG2, reducing also cell proliferation elicited at low levels of α-ZEL and β-ZEL. ROS production was not observed in cells treated with this HEFc concentration; however, it prevented ROS formation induced by treatment with 50 µM α-ZEL or β-ZEL. In summary, HEFc isolated from plants grown in northern Colombia displayed promising results against cell proliferation and oxidative stress caused by mycotoxins.

Betulinic acid alleviates zearalenone-induced uterine injury in mice

Zearalenone (ZEA) is a mycotoxin with estrogen-like biological activity, which widely present in feed and raw materials, with strong reproductive system toxicity and a major threat to animal reproduction. Betulinic acid (BA) is a natural plant compound with antioxidant, anti-inflammatory and other pharmacological activities. However, the mechanism of ZEA-induced uterine injury and the protective effect of BA have not been reported. Our results show that ZEA could cause uterine histopathological damage and cellular ultrastructural damage, affecting the secretion of sex hormones, such as estradiol (E2) and progesterone (P4), and increase the mRNA and protein expression of estrogen receptor α (ERα). ZEA could inhibit the activities of catalase (CAT) and superoxide dismutase (SOD), increase the production of malondialdehyde (MDA) and reactive oxygen species (ROS), and cause uterine oxidative stress. Furthermore, ZEA affected the homeostasis of uterine cell proliferation and death by regulating the expression of proliferating cell nuclear antigen (PCNA) and activating the mitochondrial apoptotic pathway. ZEA-induced uterine injury might be related to the activation of p38/ERK MAPK signaling pathway. However, the regulatory effect of ZEA on the uterus was reversed after BA treatment. In conclusion, the uterus is an important target organ attacked by ZEA, and BA showed a good therapeutic effect.

Recent Research on Fusarium Mycotoxins in Maize-A Review

Maize (Zea mays L.) is one of the most susceptible crops to pathogenic fungal infections, and in particular to the Fusarium species. Secondary metabolites of Fusarium spp.-mycotoxins are not only phytotoxic, but also harmful to humans and animals. They can cause acute or chronic diseases with various toxic effects. The European Union member states apply standards and legal regulations on the permissible levels of mycotoxins in food and feed. This review summarises the most recent knowledge on the occurrence of toxic secondary metabolites of Fusarium in maize, taking into account modified forms of mycotoxins, the progress in research related to the health effects of consuming food or feed contaminated with mycotoxins, and also the development of biological methods for limiting and/or eliminating the presence of the same in the food chain and in compound feed.

Immunoaffinity Cleanup and Isotope Dilution-Based Liquid Chromatography Tandem Mass Spectrometry for the Determination of Six Major Mycotoxins in Feed and Feedstuff

In this study, a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for simultaneous determination of deoxynivalenol, aflatoxin B₁, zearalenone, ochratoxin A, T-2 toxin and fumonisin B₁ in feed and feedstuff was established. The sample was extracted with an acetonitrile–water mixture (60:40, v/v), purified by an immunoaffinity column, eluted with a methanol–acetic acid mixture (98:2, v/v), and reconstituted with a methanol–water mixture (50:50, v/v) after drying with nitrogen. Finally, the reconstituted solution was detected by LC-MS/MS and quantified by isotope internal standard method. The six mycotoxins had a good linear relationship in a certain concentration range, the correlation coefficients were all greater than 0.99, the limits of detection were between 0.075 and 1.5 µg·kg⁻¹, and the limits of quantification were between 0.5 and 5 µg·kg⁻¹. The average spike recoveries in the four feed matrices ranged from 84.2% to 117.1% with relative standard deviations less than 11.6%. Thirty-six actual feed samples were analyzed for mycotoxins, and at least one mycotoxin was detected in each sample. The proposed method is reliable and suitable for detecting common mycotoxins in feed samples.

Raman spectral analysis for rapid determination of zearalenone and alpha-zearalanol

Mycotoxins, including zearalenone, are important natural products produced by fungi that occasionally contaminate agricultural commodities and pose serious health risks to consumers of food and feed. Zearalenone and its metabolite, α-zearalanol, are of significant concern due to their estrogenic and anabolic steroid activity. Several governments have regulatory standards and advisory guidelines for zearalenone and α-zearalanol. Raman and ultraviolet spectroscopy were employed with density functional theory methods to evaluate spectroscopic properties to distinguish between zearalenone and α-zearalanol systematically. Raman bands were assigned based on vibrational frequency calculations. A portable Raman spectroscopy instrument (785 nm laser) distinguished between zearalenone and α-zearalanol in a label-free manner. Many vibrational bands of zearalenone and α-zearalanol are similar, including high-intensity peaks at 1315 cm^-1 and 1650 cm^-1. However, the intensities in the Raman spectra at 1465 cm^-1, 1495 cm^-1, and 1620 cm^-1 enabled the identification of zearalenone. The Raman peak at 1450 cm^-1 is associated with α-zearalanol. These vibrational bands serve as spectral indicators to differentiate between the structurally similar zearalenone and α-zearalanol.

Bacillus velezensis A2 Inhibited the Cecal Inflammation Induced by Zearalenone by Regulating Intestinal Flora and Short-Chain Fatty Acids

Zearalenone (ZEA) as an estrogen-like mycotoxin can cause the inflammatory injury of the cecum. How to reduce the harm that ZEA causes to humans and animals is a current concern for researchers. In this study, we aimed to ascertain whether Bacillus velezensis A2 (A2) could alleviate injury caused by ZEA by regulating the intestinal flora and the content of short chain fatty acids in the cecum among mice. Our results showed that Bacillus velezensis A2 improved the fold height, myometrial thickness, and crypt depth of the cecum induced by ZEA. Enzyme-linked immunosorbent assay and Western blotting results showed that A2 could decrease the ZEA-induced increase in expression levels of IL-2, IL-6, IFN-γ, TNF-α, and FC. Studies also showed that A2 increased the content of SCFA in the cecum which was decreased by ZEA. The microbial communities in the cecum were changed when given ZEA or A2. A2 was found to greatly reduce the ZEN-induced increase in the relative abundance of p_Actinobacteria, p_Protebacteria, o_Coriobacteriales, g_Anaerotruncus, g_Pseudoflavonifractor, g_Lachnoclostridium, g_Enterorhabdus, and f_Oscillospiraceae, and increase the ZEN-induced decrease in the relative abundance of f_Coriobacteriales. Results indicated that Bacillus velezensis A2 can largely ameliorate the intestinal inflammatory injury induced by ZEA in mice by regulating the microflora and short chain fatty acids content.

Potential protective effect of lactic acid bacteria against zearalenone causing reprotoxicity in male mice

Zearalenone (ZEN) is a worldwide fusarotoxin that poses a threat to the consumer due to its chronic toxicity. Herein we examined the effects of ZEN on adult mouse testis, focusing on oxidative stress, biochemical and morphological parameters. In addition, since cytoskeletal remodeling is a key event for the production of good quality gametes, the expression and localization of two proteins, Dishevelled-associated activator of morphogenesis 1 (DAAM1) and Prolyl endopeptidase (PREP), involved in cytoskeletal dynamics during spermatogenesis were evaluated. To ameliorate the testicular dysfunction induced by ZEN we tested the eventual protective effects of lactic bacteria Lactobacillus plantarum MON03 (LP) on its reprotoxicity. Adult male mice were then treated daily for 2 wks by oral gavage with ZEN and/or LP. The results confirmed that ZEN altered sperm parameters, generated oxidative stress and provoked structural alteration, evidenced by the increased number of abnormal seminiferous tubules and of apoptotic cells, particularly Leydig cells. Interestingly, at molecular level we evaluated, for the first time, the ability of ZEN to alter DAAM1 and PREP protein level and localization. Moreover, the co-treatment with LP, thanks to its capacity to reduce ZEN bioavailability in the gastrointestinal tract, ameliorated all the considered parameters. These results suggest the use of this probiotic as food supplement to prevent/counteract ZEN-induced reprotoxicity.

Elucidation of xenoestrogen metabolism by non-targeted, stable isotope-assisted mass spectrometry in breast cancer cells

Environmental exposure to xenoestrogens, i.e., chemicals that imitate the hormone 17β-estradiol, has the potential to influence hormone homeostasis and action. Detailed knowledge of xenobiotic biotransformation processes in cell models is key when transferring knowledge learned from in vitro models to in vivo relevance. This study elucidated the metabolism of two naturally-occurring phyto- and mycoestrogens; namely genistein and zearalenone, in an estrogen receptor positive breast cancer cell line (MCF-7) with the aid of stable isotope-assisted metabolomics and the bioinformatic tool MetExtract II. Metabolism was studied in a time course experiment after 2 h, 6 h and 24 h incubation. Twelve and six biotransformation products of zearalenone and genistein were detected, respectively, clearly demonstrating the abundant xenobiotic biotransformation capability of the cells. Zearalenone underwent extensive phase-I metabolism resulting in α-zearalenol (α-ZEL), a molecule known to possess a significantly higher estrogenicity, and several phase-II metabolites (sulfo- and glycoconjugates) of the native compound and the major phase I metabolite α-ZEL. Moreover, potential adducts of zearalenone with a vitamin and several hydroxylated metabolites were annotated. Genistein metabolism resulted in sulfation, combined sulfation and hydroxylation, acetylation, glucuronidation and unexpectedly adduct formation with pentose- and hexose sugars. Kinetics of metabolite formation and subsequent excretion into the extracellular medium revealed a time-dependent increase in most biotransformation products. The untargeted elucidation of biotransformation products formed during cell culture experiments enables an improved and more meaningful interpretation of toxicological assays and has the potential to identify unexpected or unknown metabolites.

Updated Review of the Toxicity of Selected Fusarium Toxins and Their Modified Forms

Mycotoxins are one of the most dangerous food and feed contaminants, hence they have significant influence on human and animal health. This study reviews the information reported over the last few years on the toxic effects of the most relevant and studied Fusarium toxins and their modified forms. Deoxynivalenol (DON) and its metabolites can induce intracellular oxidative stress, resulting in DNA damage. Recent studies have also revealed the capability of DON and its metabolites to disturb the cell cycle and alter amino acid expression. Several studies have attempted to explore the mechanism of action of T-2 and HT-2 toxins in anorexia induction. Among other findings, two neurotransmitters associated with this process have been identified, namely substance P and serotonin (5-hydroxytryptamine). For zearalenone (ZEN) and its metabolites, the literature points out that, in addition to their generally acknowledged estrogenic and oxidative potentials, they can also modify DNA by altering methylation patterns and histone acetylation. The ability of the compounds to induce alterations in the expression of major metabolic genes suggests that these compounds can contribute to the development of numerous metabolic diseases, including type 2 diabetes.

Tannic acid repair of zearalenone-induced damage by regulating the death receptor and mitochondrial apoptosis signaling pathway in mice

Zearalenone (ZEA) is an estrogenic toxin produced by Fusarium strains, that is widely present in crops, and endangers the reproductive system of animals. Tannic acid (TA) is a natural polyphenolic substance that is widespread in the roots, stems, and leaves of plants, and has special pharmacological activity. This study was designed to investigate the therapeutic effect of TA on ZEA-induced ovarian damage in mice and to explore the molecular mechanism involved. Ninety healthy Kunming female mice were divided into six equal groups. All the groups but the control group were administered daily with ZEA [10 mg/kg body weight (bw)] orally, for 7 days, to induce damage to the reproductive system. Some groups were also administered with TA (50, 100, and 200 mg/bw) for 7 days. Mice were euthanized 24 h later to allow for collection of serum and ovaries. TA can effectively alleviate the appearance of congestion and redness of the ovary, caused by ZEA, and increase the number of healthy growing follicles. Moreover, the estrogen content and the levels of MDA and ROS in the ovaries can be effectively reduced by TA. It can also reduce the apoptosis of ovarian cells, decreases the protein expression of the estrogen receptor, Fas, Fasl, caspase-3, caspase-8, caspase-9, and Bax, and increases the protein expression of Bcl-2. Our study indicates that TA reduces the strong estrogen and oxidative damage induced by ZEA, and these therapeutic effects may be partially mediated by the death receptor and mitochondrial apoptosis signaling pathway.

Deoxynivalenol and Zearalenone-Synergistic or Antagonistic Agri-Food Chain Co-Contaminants?

Deoxynivalenol (DON) and Zearalenone (ZEN) are two commonly co-occurring mycotoxins produced by members of the genus Fusarium. As important food chain contaminants, these can adversely affect both human and animal health. Critically, as they are formed prior to harvesting, their occurrence cannot be eliminated during food production, leading to ongoing contamination challenges. DON is one of the most commonly occurring mycotoxins and is found as a contaminant of cereal grains that are consumed by humans and animals. Consumption of DON-contaminated feed can result in vomiting, diarrhoea, refusal of feed, and reduced weight gain in animals. ZEN is an oestrogenic mycotoxin that has been shown to have a negative effect on the reproductive function of animals. Individually, their mode of action and impacts have been well-studied; however, their co-occurrence is less well understood. This common co-occurrence of DON and ZEN makes it a critical issue for the Agri-Food industry, with a fundamental understanding required to develop mitigation strategies. To address this issue, in this targeted review, we appraise what is known of the mechanisms of action of DON and ZEN with particular attention to studies that have assessed their toxic effects when present together. We demonstrate that parameters that impact toxicity include species and cell type, relative concentration, exposure time and administration methods, and we highlight additional research required to further elucidate mechanisms of action and mitigation strategies.

Endocrine disrupting chemicals (EDCs) and sex steroid receptors

Sex-steroid receptors (SSRs) are essential mediators of estrogen, progestin, and androgen signaling that are critical in vast aspects of human development and multi-organ homeostasis. Dysregulation of SSR function has been implicated in numerous pathologies including cancers, obesity, Type II diabetes mellitus, neuroendocrine disorders, cardiovascular disease, hyperlipidemia, male and female infertility, and other reproductive disorders. Endocrine disrupting chemicals (EDCs) modulate SSR function in a wide variety of cell and tissues. There exists strong experimental, clinical, and epidemiological evidence that engagement of EDCs with SSRs may disrupt endogenous hormone signaling leading to physiological abnormalities that may manifest in disease. In this chapter, we discuss the molecular mechanisms by which EDCs interact with estrogen, progestin, and androgen receptors and alter SSR functions in target cells. In addition, the pathological consequences of disruption of SSR action in reproductive and other organs by EDCs is described with an emphasis on underlying mechanisms of receptors dysfunction.

Fungal Toxins and Host Immune Responses

Fungi are ubiquitous organisms that thrive in diverse natural environments including soils, plants, animals, and the human body. In response to warmth, humidity, and moisture, certain fungi which grow on crops and harvested foodstuffs can produce mycotoxins; secondary metabolites which when ingested have a deleterious impact on health. Ongoing research indicates that some mycotoxins and, more recently, peptide toxins are also produced during active fungal infection in humans and experimental models. A combination of innate and adaptive immune recognition allows the host to eliminate invading pathogens from the body. However, imbalances in immune homeostasis often facilitate microbial infection. Despite the wide-ranging effects of fungal toxins on health, our understanding of toxin-mediated modulation of immune responses is incomplete. This review will explore the current understanding of fungal toxins and how they contribute to the modulation of host immunity.

Identification of a Bacillus amyloliquefaciens H6 Thioesterase Involved in Zearalenone Detoxification by Transcriptomic Analysis

Zearalenone (ZEA), a nonsteroidal estrogenic mycotoxin produced by Fusarium graminearum, induces hyperestrogenic responses in mammals and can cause reproductive disorders in farm animals. In this study, a transcriptome analysis of Bacillus amyloliquefaciens H6, which was previously identified as a ZEA-degrading bacterium, was conducted with high-throughput sequencing technology, and the differentially expressed genes were subjected to gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG) enrichment analyses. Among the 16 upregulated genes, BAMF_RS30125 was predicted to be the key gene responsible for ZEA degradation. The protein encoded by BAMF_RS30125 was then expressed in Escherichia coli, and this recombinant protein (named ZTE138) significantly reduced the ZEA content, as determined by the enzyme-linked immunosorbent assay (ELISA) and high-performance liquid chromatography (HPLC), and decreased the proliferating activity of ZEA in MCF-7 cells. What is more, the liquid chromatography-tandem mass spectrometry (LC-MS/MS) results showed that the relative molecular mass and the structure of ZEA also changed. Sequence alignment of the ZTE138 protein showed that it is a protease that belongs to the YBGC/FADM family of coenzyme A thioesterases, and thus, the protein can presumably cleave the ZEA lactone bond and break down its macrolide ring.

Zearalenone nephrotoxicity: DNA fragmentation, apoptotic gene expression and oxidative stress protected by Lactobacillus plantarum MON03

The present study was conducted to determine the abilities of the living Lactobacillus plantarum MON03 cells to degrade Zearalenone (ZEN) in liquid medium, and to elucidate the preventive effect in ZEN-contaminated balb/c mice showing kidney damage. The DNA fragmentation, Bcl-2 and Bax gene expression, caspase-3 activity, mRNA level of inflammation-regulating cytokines and histology of kidney tissues were examined. Female Balb/c mice were divided into four groups (10/group) and treated daily for 2 wk by oral gavage with lactic acid bacteria (L. plantarum MON03) 2 × 10⁹ CFU/L, ~2 mg/kg only, ZEN (40 mg/kg BW) only, ZEN (40 mg/kg BW) + lactic acid bacteria (L. plantarum MON03, 2 × 10⁹ CFU/L, ~2 mg/kg). Control group received vehicle. At the end of experiment, the kidney was collected for the determination of DNA fragmentation, Bcl-2 and Bax gene expression,caspase-3 activity, Malondialdehyde (MDA), and glutathione peroxidase (GSH-Px) content, as well as for any alterations in expression of total antioxidant activity (TAC) and mRNA levels of inflammation-regulating cytokines (e.g., IL-10, IL-6, TNF-alpha). The results indicated that, kidney cells exposure to ZEN led to increased caspase-3 activity, MDA, and IL-10, IL-6, TNF-alpha and Bax mRNA levels, but decreased TAC content and down-regulated expression of GSH-Px and CAT and Bcl-2 mRNA. Co-treatment with ZEN plus LP suppressed the levels of DNA fragmentation; normalized kidney MDA and increased CAT levels, up-regulated expression of GSH-Px and CAT, and normalized mRNA levels of the analyzed cytokines. It's concluded that ZEN might have toxic effects in kidney. Further, it can be seen that use of LP induced protective effects against the oxidative stress and kidney toxicity of ZEN in part through adhesion (and so likely diminished bioavailability).

Transfer and Metabolism of the Xenoestrogen Zearalenone in Human Perfused Placenta

BACKGROUND

Pregnancy is a sensitive condition during which adverse environmental exposures should be monitored thoroughly and minimized whenever possible. In particular, the hormone balance during gestation is delicate, and disturbance may cause acute or chronic long-term health effects. A potential endocrine disruption may be provoked by in utero exposure to xenoestrogens mimicking endogenous estrogens. The mycoestrogen zearalenone (ZEN), a toxic fungal secondary metabolite and mycotoxin found frequently in food and feed, constitutes a prominent example.

OBJECTIVES

We performed a comprehensive assessment of the transfer as well as phase I and phase II metabolism of ZEN at the human placental barrier.

METHODS

Human placentas were perfused with 1μM (318μg/L) ZEN for 6 h. Samples from the maternal and fetal compartment, placental tissue, and fetal plasma were analyzed by a highly sensitive UHPLC-MS/MS assay to detect ZEN as well as nine key metabolites (α-zearalenol, β-zearalenol, zearalanone, α-zearalanol, β-zearalanol, ZEN-14-glucuronide, α-zearalenol-14-glucuronide, β-zearalenol-14-glucuronide, ZEN-14-sulfate).

RESULTS

The model revealed a fast maternofetal transfer of ZEN across the human placental barrier. We also unraveled phase I and phase II metabolism of the parent toxin ZEN into the approximately 70-times more estrogenic α-zearalenol and the less active ZEN-14-sulfate conjugate, which are effectively released into the maternal and fetal circulation in considerable amounts.

CONCLUSIONS

Our findings suggest that exposure to ZEN (such as through consumption of ZEN-contaminated cereal-based products) during pregnancy may result in in utero exposure of the fetus, not only to ZEN but also some of its highly estrogenically active metabolites. In the light of the known affinity of ZEN and potentially co-occurring xenoestrogens to the estrogen receptor, and our results demonstrating placental transfer of ZEN and its metabolites in an ex vivo model, we recommend further research and more comprehensive assessment of gestational exposures in women. https://doi.org/10.1289/EHP4860.

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

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.

The effect of individual and mixtures of mycotoxins and persistent organochloride pesticides on oestrogen receptor transcriptional activation using in vitro reporter gene assays

The mycotoxins zearalenone (ZEN) and alpha-zearalenone (α-ZOL), which are common contaminants of agri-food products, are known for their oestrogenic potential. In addition to mycotoxins, food may also contain pesticides with oestrogenic properties such as 1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane (p,p'-DDT) and 1,1-dichloro-2,2-bis(p-chlorophenyl) ethylene (p,p'-DDE), raising the question on the potential effects of individual and combinations of these xeno-oestrogens on the action of natural oestrogens. The present study employed a mammalian reporter gene assay to assess the effects individual and binary combinations of these environmental and food-borne contaminants on oestrogen nuclear receptor (ER) transactivation. As expected, α-ZOL and ZEN exhibited the strongest oestrogenic potency (EC₅₀: 0.27 ± 0.121 nM and 1.32 ± 0.0956 nM, respectively) whereas p,p'-DDT and p,p'-DDE had weak ER agonistic activity with the maximal response of 28.70 ± 2.97% and 18.65 ± 1.77%, respectively. Concurrent treatment of the mycotoxins and/or pesticides, individually or in binary combination, with 17β-oestradiol (E₂) showed either additive, synergistic or antagonistic interactive effects on E₂-mediated ER response, depending on the combination ratios, the concentration range of xeno-oestrogens, and the concentration of E₂. This study highlights the importance of assessing the mixture effects of chemical contaminants in risk assessment, especially in the area of reproductive and developmental toxicity.

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Zearalenone (ZEA) is a non-steroidal estrogen mycotoxin produced by several Gibberella and Fusarium species. Accumulating evidence has indicated that ZEA strongly stimulates cell proliferation. However the detailed molecular and cellular mechanisms of ZEA-mediated induction of cell proliferation have not yet been completely explained. The aim of this study was to detect the role of miRNAs in ZEA-mediated induction of cell proliferation. The effects of ZEA on cell proliferation were assessed using a cell counting kit assay and xCELLigence system. Micro-RNA sequencing was performed after treatment of TM3 cells with ZEA (0.01 μmol/L) for different time periods (0, 2, 6 and 18 h). Cell function and pathway analysis of the miRNA target genes were performed by Ingenuity Pathway Analysis (IPA). We found that ZEA promotes TM3 cell proliferation at low concentrations. miRNA sequenceing revealed 66 differentially expressed miRNAs in ZEA-treated cells in comparison to the untreated control ( p < 0.05). The miRNA sequencing indicated that compared to control group, there were 66 miRNAs significant change (p < 0.05) in ZEA-treated groups. IPA analysis showed that the predicated miRNAs target gene involved in cell Bio-functions including cell cycle, growth and proliferation, and in signaling pathways including MAPK and RAS-RAF-MEK-ERK pathways. Results from flow cytometry and Western Blot analysis validated the predictions that ZEA can affect cell cycle, and the MAPK signaling pathway. Taking these together, the cell proliferation induced ZEA is regulated by miRNAs. The results shed light on the molecular and cellular mechanisms for the mediation of ZEA to induce proliferation.

Cytotoxic and inflammatory effects of individual and combined exposure of HepG2 cells to zearalenone and its metabolites

Zearalenone (ZEA), a mycotoxin produced by several Fusarium spp., is most commonly found as a contaminant in stored grain. ZEA derivatives (α-zearalenol (α-ZOL), β-zearalenol (β-ZOL)) can also be produced by Fusarium spp. in corn stems infected by fungi in the field. Also, following oral exposure, zearalenone is metabolized in various tissues, particularly in the liver, the major metabolites being α-ZOL and β-ZOL. The co-exposure of cells to mixture of a combination of mycotoxins may cause an increase of toxicity produced by these mycotoxins. In this in vitro study, we investigated the combined effects of ZEA, α-ZOL, β-ZOL in binary mixtures on the viability and inflammatory response of human liver cancer cell line (HepG2). Cell viability was assessed after 72 h using a neutral red assay. Effect of the toxins and their binary combinations on the expression of genes involved in inflammation (IL-1β, TNF-α, and IL-8) were assessed through qPCR. Our viability data showed that irrespective of the toxin combinations, the toxins have synergistic effect. ZEA + α-ZOL and ZEA + β-ZOL mixtures have induced a slight to high antagonistic response on inflammatory cytokines at low concentrations that have turned into strong synergism for high concentrations. α-ZOL + β-ZOL showed antagonistic effects on inflammation for IL-1β and TNF-α, but act synergic for IL-8 at high toxin concentrations. This study clearly shows that co-contamination of food and feed with ZEA metabolites should be taken into consideration, as the co-exposure to mycotoxins might result in stronger adverse effect than resulted from the exposure to individual toxin.

Effects of zearalenone and its derivatives on the synthesis and secretion of mammalian sex steroid hormones: A review

Zearalenone (ZEA), a non-steroidal estrogen mycotoxin produced by several species of Fusarium fungi, can be metabolized into many other derivatives by microorganisms, plants, animals and humans. It can affect mammalian reproductive capability by impacting the synthesis and secretion of sex hormones, including testosterone, estradiol and progesterone. This review summarizes the mechanisms in which ZEA and its derivatives disturb the synthesis and secretion of sex steroid hormones. Because of its structural analogy to estrogen, ZEA and its derivatives can exert a variety of estrogen-like effects and engage in estrogen negative feedback regulation, which can result in mediating the production of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) in the pituitary gland. ZEA and its derivatives can ultimately reduce the number of Leydig cells and granulosa cells by inducing oxidative stress, endoplasmic reticulum (ER) stress, cell cycle arrest, cell apoptosis, and cell regeneration delay. Additionally, they can disrupt the mitochondrial structure and influence mitochondrial functions through overproduction of reactive oxygen species (ROS) and aberrant autophagy signaling ways. Finally, ZEA and its derivatives can disturb the expressions and activities of the related steroidogenic enzymes through cross talking between membrane and nuclear estrogen receptors.

Zearalenone Promotes Cell Proliferation or Causes Cell Death?

Zearalenone (ZEA), one of the mycotoxins, exerts different mechanisms of toxicity in different cell types at different doses. It can not only stimulate cell proliferation but also inhibit cell viability, induce cell apoptosis, and cause cell death. Thus, the objective of this review is to summarize the available mechanisms and current evidence of what is known about the cell proliferation or cell death induced by ZEA. An increasing number of studies have suggested that ZEA promoted cell proliferation attributing to its estrogen-like effects and carcinogenic properties. What’s more, many studies have indicated that ZEA caused cell death via affecting the distribution of the cell cycle, stimulating oxidative stress and inducing apoptosis. In addition, several studies have revealed that autophagy and some antioxidants can reverse the damage or cell death induced by ZEA. This review thoroughly summarized the metabolic process of ZEA and the molecular mechanisms of ZEA stimulating cell proliferation and cell death. It concluded that a low dose of ZEA can exert estrogen-like effects and carcinogenic properties, which can stimulate the proliferation of cells. While, in addition, a high dose of ZEA can cause cell death through inducing cell cycle arrest, oxidative stress, DNA damage, mitochondrial damage, and apoptosis.

Estrogen Receptor α Is Crucial in Zearalenone-Induced Invasion and Migration of Prostate Cancer Cells

Zearalenone (ZEA), a mycotoxin produced in the genus Fusarium, binds to estrogen receptors (ER) and is therefore regarded as an endocrine disruptor. ZEA has also been found to modulate the proliferation and apoptosis of prostate cancer cells in a dose-dependent manner. This study evaluates whether the effect of a low dose of ZEA (0.1 and 0.001 nM) on the invasion and migration of prostate cancer cell line PC3 is associated with ERs expression. The invasion and migration was evaluated by modified Boyden chamber assay, scratch assay, gelatin zymography, Real Time qPCR (RTqPCR) and Western blot. The involvement of ERs was evaluated with the selective ER antagonists: estrogen receptor α (ERα) antagonist 1,3-bis (4-hydroxyphenyl)-4-methyl-5-[4-(2-piperidinylethoxy) phenol]-1H-pyrazole dihydrochloride (MPP) and estrogen receptor β (ERβ) antagonist 4-[2–phenyl-5,7–bis (trifluoromethyl) pyrazolo [1,5-a]-pyrimidin-3-yl] phenol (PHTPP). ZEA was found to modulate cell motility dependent on estrogen receptors, particularly ERα. Increased cell migration and invasion were associated with increased MMP-2 and MMP-9 activity as well as the up-regulation of the EMT-associated genes vimentin (VIM), zinc finger E-box-binding homeobox 1/2 (ZEB1/2) and transforming growth factor β 1 (TGFβ1). In conclusion, ZEA might modulate the invasiveness of prostate cancer cells dependently on ERα expression.

Toxicodynamics of Mycotoxins in the Framework of Food Risk Assessment-An In Silico Perspective

Mycotoxins severely threaten the health of humans and animals. For this reason, many countries have enforced regulations and recommendations to reduce the dietary exposure. However, even though regulatory actions must be based on solid scientific knowledge, many aspects of their toxicological activity are still poorly understood. In particular, deepening knowledge on the primal molecular events triggering the toxic stimulus may be relevant to better understand the mechanisms of action of mycotoxins. The present work presents the use of in silico approaches in studying the mycotoxins toxicodynamics, and discusses how they may contribute in widening the background of knowledge. A particular emphasis has been posed on the methods accounting the molecular initiating events of toxic action. In more details, the key concepts and challenges of mycotoxins toxicology have been introduced. Then, topical case studies have been presented and some possible practical implementations of studying mycotoxins toxicodynamics have been discussed.