Zearalenone as an endocrine disruptor in humans

Comparison of Strategies to Overcome Drug Resistance: Learning from Various Kingdoms

Drug resistance, especially antibiotic resistance, is a growing threat to human health. To overcome this problem, it is significant to know precisely the mechanisms of drug resistance and/or self-resistance in various kingdoms, from bacteria through plants to animals, once more. This review compares the molecular mechanisms of the resistance against phycotoxins, toxins from marine and terrestrial animals, plants and fungi, and antibiotics. The results reveal that each kingdom possesses the characteristic features. The main mechanisms in each kingdom are transporters/efflux pumps in phycotoxins, mutation and modification of targets and sequestration in marine and terrestrial animal toxins, ABC transporters and sequestration in plant toxins, transporters in fungal toxins, and various or mixed mechanisms in antibiotics. Antibiotic producers in particular make tremendous efforts for avoiding suicide, and are more flexible and adaptable to the changes of environments. With these features in mind, potential alternative strategies to overcome these resistance problems are discussed. This paper will provide clues for solving the issues of drug resistance.

Zearalenone regulates endometrial stromal cell apoptosis and migration via the promotion of mitochondrial fission by activation of the JNK/Drp1 pathway

Increased endometrial stromal cell (ESC) survival and migration is responsible for the development and progression of endometriosis. However, little is known about the mechanisms underlying ESC survival and migration, and limited therapeutic strategies that are able to reverse these abnormalities are available. The present study investigated the effects of zearalenone (ZEA) on ESC survival and migration, particularly focusing on mitochondrial fission and the c‑Jun N‑terminal kinase (JNK)/dynamin‑related protein 1 (Drp1) pathway. The results revealed that ZEA induced ESC apoptosis in a dose‑dependent manner. Furthermore, ZEA treatment triggered excessive mitochondrial fission resulting in structural and functional mitochondrial damage, leading to the collapse of the mitochondrial membrane potential and subsequent leakage of cytochrome c into the cytoplasm. This triggered the mitochondrial pathway of apoptosis. Additionally, ZEA‑induced mitochondrial fission decreased ESC migration through F‑actin/G‑actin homeostasis dysregulation. ZEA also increased JNK phosphorylation and subsequently Drp1 phosphorylation at the serine 616 position, resulting in Drp1 activation. JNK/Drp1 pathway inhibition abolished the inhibitory effects of ZEA on ESC survival and migration. In summary, the present study demonstrated that ZEA reduced ESC survival and migration through the stimulation of mitochondrial fission by activation of the JNK/Drp1 pathway.

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.

Zearalenone Uptake and Biotransformation in Micropropagated Triticum durum Desf. Plants: A Xenobolomic Approach

A model was set up to elucidate the uptake, translocation, and metabolic fate of zearalenone (ZEN) in durum wheat. After treatment with ZEN, roots and shoots were profiled with LC-HRMS. A comprehensive description of in planta ZEN biotransformation and a biotechnological evaluation of the model were obtained. Up to 200 μg ZEN were removed by each plantlet after 14 days. Most ZEN and its masked forms were retained in roots, while minimal amounts were detected in leaves. Sixty-two chromatographic peaks were obtained, resulting in 7 putative phase I and 18 putative phase II metabolites. ZEN16Glc and ZEN14Glc were most abundant in roots, sulfo-conjugates and zearalenol derivatives were unable to gain systemic distribution, while distinct isomers of malonyl conjugates were found in leaves and roots. This study underlines the potential ZEN occurrence in plants without an ongoing Fusarium infection. Micropropagation may represent a tool to investigate the interplay between mycotoxins and wheat.

Individual and Combined Effects of Fumonisin B₁, Deoxynivalenol and Zearalenone on the Hepatic and Renal Membrane Lipid Integrity of Rats

(1) Background and (2) Methods: A 14-day in vivo, multitoxic (pure mycotoxins) rat experiment was conducted with zearalenone (ZEA; 15 μg/animal/day), deoxynivalenol (DON; 30 μg/animal/day) and fumonisin B₁ (FB₁; 150 μg/animal/day), as individual mycotoxins, binary (FD, FZ and DZ) and ternary combinations (FDZ), via gavage in 1 mL water boluses. (3) Results: Body weight was unaffected, while liver (ZEA↑ vs. DON) and kidney weight (ZEA↑ vs. FDZ) increased. Hepatocellular membrane lipid fatty acids (FAs) referred to ceramide synthesis disturbance (C20:0, C22:0), and decreased unsaturation (C22:5 n3 and unsat. index), mainly induced by DON and to a lesser extent by ZEA. The DON-FB₁ interaction was additive on C20:0 in liver lipids. In renal phospholipids, ZEA had the strongest effect on the FA profile, affecting the saturated (C18:0) and many n6 FAs; ZEA was in an antagonistic relationship with FB₁ (C18:0) or DON (C18:2 n6, C20:1 n9). Hepatic oxidative stress was the most expressed in FD (reduced glutathione and glutathione peroxidase), while the nephrotoxic effect was further supported by lipid peroxidation (malondialdehyde) in the DON treatment. (4) Conclusions: In vivo study results refer to multiple mycotoxin interactions on membrane FAs, antioxidants and lipid peroxidation compounds, needing further testing.

Application of Activated Carbon Derived from Seed Shells of Jatropha curcas for Decontamination of Zearalenone Mycotoxin

In the present study, activated carbon (AC) was derived from seed shells of Jatropha curcas and applied to decontaminate the zearalenone (ZEA) mycotoxin. The AC of J. curcas (ACJC) was prepared by ZnCl₂ chemical activation method and its crystalline structure was determined by X-ray diffraction analysis. The crystalline graphitic nature of ACJC was confirmed from the Raman spectroscopy. Scanning electron microscope showed the porous surface morphology of the ACJC surface with high pore density and presence of elemental carbon was identified from the energy dispersive X-ray analysis. From Brunauer–Emmett–Teller (BET) analysis, S_BET, micropore area, and average pore diameter of ACJC were calculated as 822.78 (m²/g), 255.36 (m²/g), and 8.5980 (Å), respectively. The adsorption of ZEA by ACJC was accomplished with varying contact time, concentration of ZEA and ACJC, and pH of media. The ACJC has adsorbed the ZEA over a short period of time and adsorption of ZEA was dependent on the dose of ACJC. The effect of different pH on adsorption of ZEA by ACJC was not much effective. Desorption studies confirmed that adsorption of ZEA by ACJC was stable. The adsorption isotherm of ZEA by ACJC was well fitted with Langmuir model rather than Freundlich and concluded the homogeneous process of sorption. The maximum adsorption of ZEA by ACJC was detected as 23.14 μg/mg. Finally, adsorption property of ACJC was utilized to establish ACJC as an antidote against ZEA-induced toxicity under in vitro in neuro-2a cells. The percentage of live cells was high in cells treated together with a combination of ZEA and ACJC compared to ZEA treated cells. In a similar way, ΔΨ_M was not dropped in cells exposed to combination of ACJC and ZEA compared to ZEA treated cells. Furthermore, cells treated with a combination of ZEA and ACJC exhibited lower level of intracellular reactive oxygen species and caspase-3 compared to ZEA treated cells. These in vitro studies concluded that ACJC has successfully protected the cells from ZEA-induced toxicity by lowering the availability of ZEA in media as a result of adsorption of ZEA. The study concluded that ACJC was a potent decontaminating agent for ZEA and could be used as an antidote against ZEA-induced toxicity.

Characterization and crystal structure of a novel zearalenone hydrolase from Cladophialophora bantiana

Zearalenone (ZEN) is a mycotoxin which causes huge economic losses in the food and animal feed industries. The lactonase ZHD101 from Clonostachys rosea, which catalyzes the hydrolytic degradation of ZEN, is the only known ZEN-detoxifying enzyme. Here, a protein homologous to ZHD101, denoted CbZHD, from Cladophialophora batiana was expressed and characterized. Sequence alignment indicates that CbZHD possesses the same catalytic triad and ZEN-interacting residues as found in ZHD101. CbZHD exhibits optimal enzyme activity at 35°C and pH 8, and is sensitive to heat treatment. The crystal structure of apo CbZHD was determined to 1.75 Å resolution. The active-site compositions of CbZHD and ZHD101 were analyzed.

The dose-dependent effect of zearalenone on mitochondrial metabolism, plasma membrane permeabilization and cell cycle in human prostate cancer cell lines

Zearalenone (ZEA) is a nonsteroidal mycotoxin produced by several fungi of the genus Fusarium spp. It is known to play various roles in the regulation of the prostate cancer cell cycle, including carcinogenesis. The present study evaluates the influence of ZEA on the mitochondrial metabolism, plasma membrane permeabilization and cell cycle of prostate cancer cells. At concentrations of 100 nM and 0.3 nM, ZEA caused a decrease in the oxidative activity of mitochondria, as well as increases in LDH release, apoptosis induction and the number of cells in the G0/G1 phase. The opposite effect was observed for lower concentrations (0.1 nM and 0.001 nM). These in vitro studies indicate that ZEA might have pro- and antiproliferative properties in prostate cancer cells, at concentrations 0.1 nM, 0.001 nM and 0.3 nM, 100 nM, respectively.

Risks for animal health related to the presence of zearalenone and its modified forms in feed

Zearalenone (ZEN), a mycotoxin primarily produced by Fusarium fungi, occurs predominantly in cereal grains. The European Commission asked EFSA for a scientific opinion on the risk to animal health related to ZEN and its modified forms in feed. Modified forms of ZEN occurring in feed include phase I metabolites α‐zearalenol (α‐ZEL), β‐zearalenol (β‐ZEL), α‐zearalanol (α‐ZAL), β‐zearalanol (β‐ZAL), zearalanone (ZAN) and phase II conjugates. ZEN has oestrogenic activity and the oestrogenic activity of the modified forms of ZEN differs considerably. For ZEN, the EFSA Panel on Contaminants in the Food Chain (CONTAM) established no observed adverse effect levels (NOAELs) for pig (piglets and gilts), poultry (chicken and fattening turkeys), sheep and fish (extrapolated from carp) and lowest observed effect level (LOAEL) for dogs. No reference points could be established for cattle, ducks, goats, horses, rabbits, mink and cats. For modified forms, no reference points could be established for any animal species and relative potency factors previously established from rodents by the CONTAM Panel in 2016 were used. The dietary exposure was estimated on 17,706 analytical results with high proportions of left‐censored data (ZEN about 60%, ZAN about 70%, others close to 100%). Samples for ZEN were collected between 2001 and 2015 in 25 different European countries, whereas samples for the modified forms were collected mostly between 2013 and 2015 from three Member States. Based on exposure estimates, the risk of adverse health effects of feed containing ZEN was considered extremely low for poultry and low for sheep, dog, pig and fish. The same conclusions also apply to the sum of ZEN and its modified forms.

Occurrence, Toxicity, and Analysis of Major Mycotoxins in Food

Mycotoxins are toxic secondary metabolites produced by certain filamentous fungi (molds). These low molecular weight compounds (usually less than 1000 Daltons) are naturally occurring and practically unavoidable. They can enter our food chain either directly from plant-based food components contaminated with mycotoxins or by indirect contamination from the growth of toxigenic fungi on food. Mycotoxins can accumulate in maturing corn, cereals, soybeans, sorghum, peanuts, and other food and feed crops in the field and in grain during transportation. Consumption of mycotoxin-contaminated food or feed can cause acute or chronic toxicity in human and animals. In addition to concerns over adverse effects from direct consumption of mycotoxin-contaminated foods and feeds, there is also public health concern over the potential ingestion of animal-derived food products, such as meat, milk, or eggs, containing residues or metabolites of mycotoxins. Members of three fungal genera, Aspergillus, Fusarium, and Penicillium, are the major mycotoxin producers. While over 300 mycotoxins have been identified, six (aflatoxins, trichothecenes, zearalenone, fumonisins, ochratoxins, and patulin) are regularly found in food, posing unpredictable and ongoing food safety problems worldwide. This review summarizes the toxicity of the six mycotoxins, foods commonly contaminated by one or more of them, and the current methods for detection and analysis of these mycotoxins.

Forthcoming Challenges in Mycotoxins Toxicology Research for Safer Food-A Need for Multi-Omics Approach

The presence of mycotoxins in food represents a severe threat for public health and welfare, and poses relevant research challenges in the food toxicology field. Nowadays, food toxicologists have to provide answers to food-related toxicological issues, but at the same time they should provide the appropriate knowledge in background to effectively support the evidence-based decision-making in food safety. Therefore, keeping in mind that regulatory actions should be based on sound scientific findings, the present opinion addresses the main challenges in providing reliable data for supporting the risk assessment of foodborne mycotoxins.