Disturbance of antioxidant capacity produced by beauvericin in CHO-K1 cells

Exploring potential molecular targets and therapeutic efficacy of beauvericin in triple-negative breast cancer cells

Triple negative breast cancer (TNBC) presents a significant global health concern due to its aggressive nature, high mortality rate and limited treatment options, highlighting the urgent need for targeted therapies. Beauvericin, a bioactive fungal secondary metabolite, possess significant anticancer potential, although its molecular targets in cancer cells remain unexplored. This study has investigated possible molecular targets of beauvericin and its therapeutic insights in TNBC cells. In silico studies using molecular docking and MD simulation predicted the molecular targets of beauvericin. The identified targets included MRP-1 (ABCC1), HDAC-1, HDAC-2, LCK and SYK with average binding energy of -90.1, -44.3, -72.1, -105 and -60.8 KJ/mol, respectively, implying its multifaceted roles in reversing drug resistance, inhibiting epigenetic modulators and oncogenic tyrosine kinases. Beauvericin has significantly reduced the viability of MDA-MB-231 and MDA-MB-468 cells, with IC50 concentrations of 4.4 and 3.9 µM, while concurrently elevating the intracellular ROS by 9.0 and 7.9 folds, respectively. Subsequent reduction of mitochondrial transmembrane potential in TNBC cells, has confirmed the induction of oxidative stress, leading to apoptotic cell death, as observed by flow cytometric analyses. Beauvericin has also arrested cell cycle at G1-phase and impaired the spheroid formation and clonal expansion abilities of TNBC cells. The viability of spheroids was reduced upon beauvericin treatment, exhibiting IC50 concentrations of 10.3 and 6.2 µM in MDA-MB-468 and MDA-MB-231 cells, respectively. In conclusion, beauvericin has demonstrated promising therapeutic potential against TNBC cells through possible inhibition of MRP-1 (ABCC1), HDAC-1, HDAC-2, LCK and SYK.

Beauvericin Reverses Epithelial-to-Mesenchymal Transition in Triple-Negative Breast Cancer Cells through Regulation of Notch Signaling and Autophagy

Metastasis stands as a prime contributor to triple-negative breast cancer (TNBC) associated mortality worldwide, presenting heightened severity and significant challenges due to limited treatment options. Addressing TNBC metastasis necessitates innovative approaches and novel therapeutics to specifically target its propensity for dissemination to distant organs. Targeted therapies capable of reversing epithelial-to-mesenchymal transition (EMT) play a crucial role in suppressing metastasis and enhancing the treatment response. Beauvericin, a promising fungal secondary metabolite, exhibits significant potential in diminishing the viability of EMT-induced TNBC cells by triggering intracellular oxidative stress, as evidenced by an enhanced reactive oxygen species level and reduced mitochondrial transmembrane potential. In monolayer cultures, it has exhibited an IC50 of 2.3 μM in both MDA-MB-468 and MDA-MB-231 cells, while in 3D spheroids, the IC50 values are 9.7 and 7.1 μM, respectively. Beauvericin has also reduced the migratory capability of MDA-MB-468 and MDA-MB-231 cells by 1.5- and 1.7-fold, respectively. Both qRT-PCR and Western blot analysis have shown significant upregulation in the expression of epithelial marker (E-cadherin) and downregulation in the expression of mesenchymal markers (N-cadherin, vimentin, Snail, Slug, and β-catenin), following treatment, indicating reversal of EMT. Furthermore, beauvericin has suppressed the Notch signaling pathway by substantially downregulating Notch-1, Notch-3, Hes-1, and cyclinD3 expression and induced autophagy as observed by elevated expression of autophagy markers LC3 and Beclin-1. In conclusion, beauvericin has successfully downregulated TNBC cell survival by inducing oxidative stress and suppressed their migratory potential by reversing EMT through the inhibition of Notch signaling and activation of autophagy.

Curcumin alleviates zearalenone-induced liver injury in mice by scavenging reactive oxygen species and inhibiting mitochondrial apoptosis pathway

Curcumin (CUR) is a compound extracted from turmeric that has a variety of functions including antioxidant and anti-inflammatory. As an estrogen-like mycotoxin, zearalenone (ZEN) not only attacks the reproductive system, but also has toxic effects on the liver. However, whether CUR can alleviate ZEN-induced liver injury remains unclear. This paper aims to investigate the protective effect of CUR against ZEN-induced liver injury in mice and explore the molecular mechanism involved. BALB/c mice were randomly divided into control (CON) group, CUR group (200 mg/kg b. w. CUR), ZEN group (40 mg/kg b. w. ZEN) and CUR+ZEN group (200 mg/kg b. w. CUR+40 mg/kg b. w. ZEN). 28 d after ZEN exposure and CUR treatment, blood and liver samples were collected for subsequent testing. The results showed that CUR reversed ZEN-induced hepatocyte swelling and necrosis in mice. It significantly reduced the serum alkaline phosphatase (ALP), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels in mice (p < 0.05). In addition, CUR significantly reduced hepatic ROS, malondialdehyde, hydrogen peroxide and apoptosis levels in mice (p < 0.05). Quantitative RT-PCR and Western blot results showed that CUR significantly reduced the expression of Bax and Caspase3, and reversed the increase of Nrf2, HO-1 and NQO1 expression in the liver of mice induced by ZEN (p < 0.05). In conclusion, CUR alleviated ZEN-induced liver injury in mice by scavenging ROS and inhibiting the mitochondrial apoptotic pathway.

Toxicity of the emerging mycotoxins beauvericin and enniatins: A mini-review

Beauvericin and enniatins, emerging mycotoxins produced mainly by Fusarium species, are natural contaminants of cereals and cereal products. These mycotoxins are cyclic hexadepsipeptides with ionophore properties and their toxicity mechanism is related to their ability to transport cations across the cell membrane. Beauvericin and enniatins are cytotoxic, as they decrease cell viability, promote cell cycle arrest, and increase apoptosis and the generation of reactive oxygen species in several cell lines. They also cause changes at the transcriptomic level and have immunomodulatory effects in vitro and in vivo. Toxicokinetic results are scarce, and, despite its proven toxic effects in vitro, no regulation or risk assessment has yet been performed due to a lack of in vivo data. This mini-review aims to report the information available in the literature on studies of in vitro and in vivo toxic effects with beauvericin and enniatins, which are mycotoxins of increasing interest to animal and human health.

Dietary beauvericin and enniatin B exposure cause different adverse health effects in farmed Atlantic salmon

The extensive use of plant ingredients in novel aquafeeds have introduced mycotoxins to the farming of seafood. The emerging enniatin B (ENNB) and beauvericin (BEA) mycotoxins have been found in the novel aquafeeds and farmed fish. Little is known about the potential toxicity of ENNs and BEA in farmed fish and their feed-to-organ transfer. Atlantic salmon (Salmo salar) pre-smolt (75.3 ± 8.10 g) were fed four graded levels of spiked chemical pure ENNB or BEA feeds for three months, in triplicate tanks. Organismal adverse health end-point assessment included intestinal function (protein digestibility), disturbed hematology (red blood cell formation), bone formation (spinal deformity), overall energy use (feed utilization), and lipid oxidative status (vitamin E). Both dietary BEA and ENNB had a low (<∼0.01%) transfer to organs (kidney > liver > brain > muscle), with a higher transfer for ENNB compared to BEA. BEA caused a growth reduction combined with a decreased protein digestion and feed conversion rate- ENNB caused a stunted growth, unrelated to feed utilization capacity. In addition, ENNB caused anemia while BEA gave an oxidative stress response. Lower bench-mark dose regression assessment showed that high background levels of ENNB in commercial salmon feed could pose a risk for animal health, but not in the case of BEA.

Stressful Effects of T-2 Metabolites and Defense Capability of HepG2 Cells

The T-2 toxin (T-2), a mycotoxin produced by several species of Fusarium which belongs to group A of trichothecenes, is rapidly metabolized, and its main metabolites are HT-2, Neosolaniol (Neo), T2-triol and T2-tetraol. In this work, the antioxidant defense system of HepG2 cells against oxidative stress induced by T-2 and its metabolites was evaluated. The results obtained demonstrated that there is an overall decrease in glutathione (GSH) levels after all mycotoxins exposure. Moreover, the GSH levels and the enzymatic activities related to GSH (GPx and GST) increased with NAC pre-treatment (glutathione precursor) and decreased with BSO pre-treatment (glutathione inhibitor). The GPx activity is increased by T2-tetraol. The GST activity increased after T-2 and T2-triol exposure; however, T2-tetraol decreased its activity. Furthermore, CAT activity increased after T-2 and T2-triol; nevertheless, Neo decreased its activity. Finally, SOD activity is increased by all mycotoxins, except after T-2 exposure. So, the damage associated with oxidative stress by T-2 and its metabolites is relieved by the antioxidant enzymes system on HepG2 cells.

Zearalenone Exposure Affects the Keap1-Nrf2 Signaling Pathway and Glucose Nutrient Absorption Related Genes of Porcine Jejunal Epithelial Cells

This study aims to examine the impact of zearalenone (ZEA) on glucose nutrient absorption and the role of the Kelch-like erythroid cell-derived protein with CNC homology-associated protein 1 (Keap1)-nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway in zearalenone-induced oxidative stress of porcine jejunal epithelial cells (IPEC-J2). For 24 and 36 h, the IPEC-J2 cells were exposed to ZEA at concentrations of 0, 10, 20, and 40 (Control, ZEA10, ZEA20, ZEA40) mol/L. With the increase of ZEA concentration and prolongation of the action time, the apoptosis rate and malondialdehyde level and relative expression of sodium-dependent glucose co-transporter 1 (Sglt1), glucose transporter 2 (Glut2), Nrf2, quinone oxidoreductase 1 (Nqo1), and hemeoxygenase 1 (Ho1) at mRNA and protein level, fluorescence intensity of Nrf2 and reactive oxygen species increased significantly (p < 0.05), total superoxide dismutase and glutathione peroxidase activities and relative expression of Keap1 at mRNA and protein level, fluorescence intensity of Sglt1 around the cytoplasm and the cell membrane of IPEC-J2 reduced significantly (p < 0.05). In conclusion, ZEA can impact glucose absorption by affecting the expression of Sglt1 and Glut2, and ZEA can activate the Keap1-Nrf2 signaling pathway by enhancing Nrf2, Nqo1, and Ho1 expression of IPEC-J2.

Role of Nrf2 Nucleus Translocation in Beauvericin-Induced Cell Damage in Rat Hepatocytes

Beauvericin (BEA), a food-borne mycotoxin metabolite derived from the fungus Beauveria Bassiana, is proven to exhibit high hepatotoxicity. However, the molecular mechanism underlying BEA-induced liver damage is not fully understood. Herein, the effect of Nrf2 nuclear translocation-induced by BEA in hepatocytes was investigated. CCK8 solution was used to determine the appropriate concentrations of BEA (0, 1, 1.5 and 2 μmol/L), and BRL3A cells were then exposed to different concentrations of BEA for 12 h. Our results reveal that BEA exposure is associated with high cytotoxicity, lowered cell viability, damaged cellular morphology, and increased apoptosis rate. BEA could lead to oxidative damage through the overproduction of ROS and unbalanced redox, trigger the activation of Nrf2 signaling pathway and Nrf2 nuclear translocation for transcriptional activation of downstream antioxidative genes. Additionally, BEA treatment upregulated the expression of autophagy-related proteins (LC3, p62, Beclin1, and ATG5) indicating a correlation between Nrf2 activation and autophagy, which warrants further studies. Furthermore, ML385, an Nrf2 inhibitor, partially ameliorated BEA-induced cell injury while CDDO, an Nrf2 activator, aggravated liver damage. The present study emphasizes the role of Nrf2 nuclear translocation in BEA-induced oxidative stress associated with the hepatotoxic nature of BEA.

Effects of Voghiera garlic extracts in neuronal human cell line against zearalenone's derivates and beauvericin

The Fusarium toxins constitute one of the largest groups of mycotoxins produced by Fusarium species, which are major pathogens of cereal plants. In the present study neuroprotection effect of Allium sativum L garlic extract which is known as Voghiera garlic, from a local garlic ecotype of Ferrara (Italy) was examined on an undifferentiated SH-SY5Y neuronal cells against ZEA's metabolites (α-zearalenol (α-ZEL) and β-zearalenol (β-ZEL)) and beauvericin (BEA) mycotoxins which are considered as the most reported Fusarium mycotoxins, via MTT (3-4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay, over 24 h and 48 h through direct treatment, simultaneous treatment and pre-treatment strategies. The results demonstrated remarkable improvement in cells viability in simultaneous and pre-treatment strategy with Voghiera garlic extract (VGE); specifically, for simultaneous treatment of VGE with β-ZEL which viability increased significantly up to 56%, and subsequently with α-ZEL and BEA by up to 38% and 37% respectively, compared to each mycotoxin tested alone for their highest concentrations assayed, while direct treatments for each mycotoxins individually decreased significantly (for α-ZEL up to 69%, for β-ZEL 82% and for BEA up to 43%). It is proposed by the present study that VGE extract found to be effective in reducing the cytotoxicity/neurotoxicity of α-ZEL, β-ZEL and BEA mycotoxins encountered in food and feed commodity.

Beauvericin (BEA) and enniatin B (ENNB)-induced impairment of mitochondria and lysosomes - Potential sources of intracellular reactive iron triggering ferroptosis in Atlantic salmon primary hepatocytes

Beauvericin (BEA) and enniatin B (ENNB) are emerging mycotoxins frequently detected in plant-based fish feed. With ionophoric properties, they have shown cytotoxic potential in mammalian models. Sensitivity in fish is still largely unknown. Primary hepatocytes isolated from Atlantic salmon (Salmo salar) were used as a model and exposed to BEA and ENNB (0.05-10 μM) for 48 h. Microscopy, evaluation of cell viability, total ATP, total H₂O₂, total iron content, total Gpx enzyme activity, and RNA sequencing were used to characterize the toxicodynamics of BEA and ENNB. Both mycotoxins became cytotoxic at ≥ 5 μM, causing condensation of the hepatocytes followed by formation of blister-like protrusions on the cell's membrane. RNA sequencing analysis at sub-cytotoxic levels indicated BEA and ENNB exposed hepatocytes to experience increased energy expenditure, elevated oxidative stress, and iron homeostasis disturbances sensitizing the hepatocytes to ferroptosis. The present study provides valuable knowledge disclosing the toxic action of these mycotoxins in Atlantic salmon primary hepatocytes.

Study of enzymatic activity in human neuroblastoma cells SH-SY5Y exposed to zearalenone's derivates and beauvericin

Beauvericin (BEA), α-zearalenol (α-ZEL) and β-zearalenol (β-ZEL), are produced by several Fusarium species that contaminate cereal grains. These mycotoxins can cause cytotoxicity and neurotoxicity in various cell lines and they are also capable of produce oxidative stress at molecular level. However, mammalian cells are equipped with a protective endogenous antioxidant system formed by no-enzymatic antioxidant and enzymatic protective systems such as glutathione peroxidase (GPx), glutathione S-transferase (GST), catalase (CAT) and superoxide dismutase (SOD). The aim of this study was evaluating the effects of α-ZEL, β-ZEL and BEA, on enzymatic GPx, GST, CAT and SOD activity in human neuroblastoma cells using the SH-SY5Y cell line, over 24 h and 48 h with different treatments at the following concentration range: from 1.56 to 12.5 μM for α-ZEL and β-ZEL, from 0.39 to 2.5 μM for BEA, from 1.87 to 25 μM for binary combinations and from 3.43 to 27.5 μM for tertiary combination. SH-SY5Y cells exposed to α-ZEL, β-ZEL and BEA revealed an overall increase in the activity of i) GPx, after 24 h of exposure up to 24-fold in individual treatments and 15-fold in binary combination; ii) GST after 24 h of exposure up to 10-fold (only in combination forms), and iii) SOD up to 3.5- and 5-fold in individual and combined treatment, respectively after 48 h of exposure. On the other hand, CAT activity decreased significantly in all treatments up to 92% after 24 h except for β-ZEL + BEA, which revealed the opposite.

Neurotoxicity of zearalenone's metabolites and beauvericin mycotoxins via apoptosis and cell cycle disruption

Cell cycle progression and programmed cell death are imposed by pathological stimuli of extrinsic or intrinsic including the exposure to neurotoxins, oxidative stress and DNA damage. All can cause abrupt or delayed cell death, inactivate normal cell survival or cell death networks. Nevertheless, the mechanisms of the neuronal cell death are unresolved. One of the cell deaths triggers which have been wildly studied, correspond to mycotoxins produced by Fusarium species, which have been demonstrated cytotoxicity and neurotoxicity through impairing cell proliferation, gene expression and induction of oxidative stress. The aim of present study was to analyze the cell cycle progression and cell death pathway by flow cytometry in undifferentiated SH-SY5Y neuronal cells exposed to α-zearalenol (α-ZEL), β-zearalenol (β-ZEL) and beauvericin (BEA) over 24 h and 48 h individually and combined at the following concentration ranges: from 1.56 to 12.5 μM for α-ZEL and β-ZEL, from 0.39 to 2.5 μM for BEA, from 1.87 to 25 μM for binary combinations and from 3.43 to 27.5 μM for tertiary combination. Alterations in cell cycle were observed remarkably for β-ZEL at the highest concentration in all treatments where engaged (β-ZEL, β-ZEL + BEA and β-ZEL + α-ZEL), for both 24 h and 48 h. by activating the cell proliferation in G0/G1 phase (up to 43.6 %) and causing delays or arrests in S and G2/M phases (up to 19.6 %). Tertiary mixtures revealed increases of cell proliferation in subG0 phase by 4-folds versus control. Similarly, for cell death among individual treatments β-ZEL showed a significant growth in early apoptotic cells population at the highest concentration assayed as well as for all combination treatments where β-ZEL was involved, in both early apoptotic and apoptotic/necrotic cell death pathways.

Beauvericin and Enniatins: In Vitro Intestinal Effects

Food and feed contamination by emerging mycotoxins beauvericin and enniatins is a worldwide health problem and a matter of great concern nowadays, and data on their toxicological behavior are still scarce. As ingestion is the major route of exposure to mycotoxins in food and feed, the gastrointestinal tract represents the first barrier encountered by these natural contaminants and the first structure that could be affected by their potential detrimental effects. In order to perform a complete and reliable toxicological evaluation, this fundamental site cannot be disregarded. Several in vitro intestinal models able to recreate the different traits of the intestinal environment have been applied to investigate the various aspects related to the intestinal toxicity of emerging mycotoxins. This review aims to depict an overall and comprehensive representation of the in vitro intestinal effects of beauvericin and enniatins in humans from a species-specific perspective. Moreover, information on the occurrence in food and feed and notions on the regulatory aspects will be provided.

The mycotoxin beauvericin impairs development, fertility and life span in the nematode Caenorhabditis elegans accompanied by increased germ cell apoptosis and lipofuscin accumulation

Beauvericin is an ubiquitous mycotoxin with relevant occurrence in food and feed. It causes a high toxicity in several cell lines, but its general mechanism of action is not fully understood and only limited in vivo studies have been performed. We used Caenorhabditis elegans as a model organism to investigate effects of beauvericin. The mycotoxin displays a moderate acute toxicity at 100 μM; at this concentration also reproductive toxicity occurred (reduction of total progeny to 32.1 %), developmental toxicity was detectable at 250 μM. However, even lower concentrations were capable to reduce stress resistance and life span of the nematode: A significant reduction was detected at 10 μM beauvericin (decrease in mean survival time of 4.3 % and reduction in life span of 12.9 %). An increase in lipofuscin fluorescence was demonstrated starting at 10 μM suggesting oxidative stress as a mechanism of beauvericin toxicity. Beauvericin (100 μM) increases the number of apoptotic germ cells comparable to the positive control UV-C (400 J/m²). Conclusion: Low concentrations of beauvericin are capable to cause adverse effects in C. elegans, which may be relevant for hazard identification of this compound.

Individual and Combined Effect of Zearalenone Derivates and Beauvericin Mycotoxins on SH-SY5Y Cells

Beauvericin (BEA) and zearalenone derivatives, α-zearalenol (α-ZEL), and β-zearalenol (β-ZEL), are produced by several Fusarium species. Considering the impact of various mycotoxins on human's health, this study determined and evaluated the cytotoxic effect of individual, binary, and tertiary mycotoxin treatments consisting of α-ZEL, β-ZEL, and BEA at different concentrations over 24, 48, and 72 h on SH-SY5Y neuronal cells, by using the MTT assay (3-(4,5-dimethylthiazol-2-yl)-2,5diphenyltetrazoliumbromide). Subsequently, the isobologram method was applied to elucidate if the mixtures produced synergism, antagonism, or additive effects. Ultimately, we determined the amount of mycotoxin recovered from the media after treatment using liquid chromatography coupled with electrospray ionization-quadrupole time-of-flight mass spectrometry (LC-ESI-qTOF-MS). The IC50 values detected at all assayed times ranged from 95 to 0.2 μM for the individual treatments. The result indicated that β-ZEL was the most cytotoxic mycotoxin when tested individually. The major effect detected for all combinations assayed was synergism. Among the combinations assayed, α-ZEL + β-ZEL + BEA and α-ZEL + BEA presented the highest cytotoxic potential with respect to the IC value. At all assayed times, BEA was the mycotoxin recovered at the highest concentration in individual form, and β-ZEL + BEA was the combination recovered at the highest concentration.

Beauvericin and ochratoxin A mycotoxins individually and combined in HepG2 cells alter lipid peroxidation, levels of reactive oxygen species and glutathione

The co-presence of more than one mycotoxin in food is being evidenced in last food surveys as reported in the literature. Beauvericin (BEA) is a non-legislated emergent mycotoxin while Ochratoxin A (OTA) has been widely studied and legislated. Concentration range individually studied was from 2.5 to 0.3 μM for BEA and from 25 to 3.1 μM for OTA; binary mixture [BEA + OTA] comprised concentrations of 1:10 ratio from [2.5 + 25] to [3.1 + 0.3] μM. Potential of toxicity of BEA in HepG2 cells was the highest at all times assayed (24, 48 and 72h). LPO was performed through malondyaldehyde (MDA) detection denoting in the binary mixture for [1.25 + 12.5] μM and at 24 and 72h the highest disturbance values. ROS denoted differences respect to the control at different times specially for OTA, while in binary combination only for few point times was denoted. Effects detected for ROS and LPO were connected with alterations detected for glutathione levels of oxidized and reduced form. A real scenario of consumers chronically exposed to different mycotoxins and their mixtures is here presented highlighting the good methodology to assess the risk from exposure to combinations of chemicals in food.

The mycotoxin beauvericin induces oocyte mitochondrial dysfunction and affects embryo development in the juvenile sheep

Beauvericin (BEA) is a mycotoxin produced by Beauveria bassiana and Fusarium species recently reported as toxic on porcine oocyte maturation and embryo development. The aim of this study was to assess, in the juvenile sheep, whether its effects are due to alterations of oocyte and/or embryo bioenergetic/oxidative status. Cumulus-oocyte-complexes (COCs) were exposed to BEA during in vitro maturation (IVM), evaluated for cumulus cell (CC) apoptosis, oocyte maturation and bioenergetic/oxidative status or subjected to in vitro fertilization (IVF) and embryo culture (IVEC). Oocyte nuclear maturation and embryo development were assessed after Hoechst staining and CC apoptosis was analysed by terminal deoxynucleotidyl transferase-mediated dUTP nick-End labeling assay and chromatin morphology after Hoechst staining by epifluorescence microscopy. Oocyte and blastocyst bioenergetic/oxidative status were assessed by confocal microscopy after mitochondria and reactive oxygen species labelling with specific probes. BEA showed various toxic effects, that is, short-term effects on somatic and germinal compartment of the COC (CCs and the oocyte) and long-term carry-over effects on developing embryos. In detail, at 5 µM, it significantly reduced oocyte maturation and immature oocytes showed increased late-stage (Type C) CC apoptosis and DNA fragmentation while matured oocytes showed unaffected CC viability but abnormal mitochondrial distribution patterns. At lower tested concentrations (3-0.5 µM), BEA did not affect oocyte maturation, but matured oocytes showed reduced mitochondrial activity. At low concentrations, BEA impaired embryo developmental capacity and blastocyst quality after IVF and IVEC. In conclusion, in the juvenile sheep, COC exposure to BEA induces CC apoptosis and oocyte mitochondrial dysfunction with negative impact on embryo development.

Fusarium Molds and Mycotoxins: Potential Species-Specific Effects

This review summarizes the information on biochemical and biological activity of the main Fusarium mycotoxins, focusing on toxicological aspects in terms of species-specific effects. Both in vitro and in vivo studies have centered on the peculiarity of the responses to mycotoxins, demonstrating that toxicokinetics, bioavailability and the mechanisms of action of these substances vary depending on the species involved, but additional studies are needed to better understand the specific responses. The aim of this review is to summarize the toxicological responses of the main species affected by Fusarium mycotoxins.

In vitro mechanisms of Beauvericin toxicity: A review

Beauvericin (BEA) is a mycotoxin produced by many species of fungus Fusarium and by Beauveria bassiana; BEA is a natural contaminant of cereals and cereals based products and possesses a wide variety of biological properties. The mechanism of action seems to be related to its ionophoric activity, that increases ion permeability in biological membranes. As a consequence, BEA causes cytotoxicity in several cell lines and is capable to produce oxidative stress at molecular level. Moreover, BEA is genotoxic (produces DNA fragmentation, chromosomal aberrations and micronucleus) and causes apoptosis with the involvement of mitochondrial pathway. However, several antioxidant mechanisms protect cells against oxidative stress produced by BEA. Despite its strong cytotoxicity, no risk assessment have been still carried out by authorities due to a lack of toxicity data, so research on BEA toxicological impact is still going on. This review reports information available regarding BEA mechanistic toxicology with the aim of updating information regarding last researches on this mycotoxin.

Transcriptomic study of the toxic mechanism triggered by beauvericin in Jurkat cells

Beauvericin (BEA), an ionophoric cyclic hexadepsipeptide mycotoxin, is able to increase oxidative stress by altering membrane ion permeability and uncoupling oxidative phosphorylation. A toxicogenomic study was performed to investigate gene expression changes triggered by BEA exposure (1.5, 3 and 5 μM; 24 h) in Jurkat cells through RNA-sequencing and differential gene expression analysis. Perturbed gene expression was observed in a concentration dependent manner, with 43 differentially expressed genes (DEGs) overlapped in the three studied concentrations. Gene ontology (GO) analysis showed several biological processes related to electron transport chain, oxidative phosphorylation, and cellular respiration significantly altered. Molecular functions linked to mitochondrial respiratory chain and oxidoreductase activity were over-represented (q-value < 0.01). Pathway analysis revealed oxidative phosphorylation and electron transport chain as the most significantly altered pathways in all studied doses (z-score > 1.96; adj p-value < 0.05). 77 genes involved in the respiratory chain were significantly down-regulated at least at one dose. Moreover, 21 genes related to apoptosis and programmed cell death, and 12 genes related to caspase activity were significantly altered, mainly affecting initiator caspases 8, 9 and 10. The results demonstrated BEA-induced mitochondrial damage affecting the respiratory chain, and pointing to apoptosis through the caspase cascade in human lymphoblastic T cells.

Emerging Mycotoxins: Beyond Traditionally Determined Food Contaminants

Modern analytical techniques can determine a multitude of fungal metabolites contaminating food and feed. In addition to known mycotoxins, for which maximum levels in food are enforced, also currently unregulated, so-called "emerging mycotoxins" were shown to occur frequently in agricultural products. The aim of this review is to critically discuss the relevance of selected emerging mycotoxins to food and feed safety. Acute and chronic toxicity as well as occurrence data are presented for enniatins, beauvericin, moniliformin, fusaproliferin, fusaric acid, culmorin, butenolide, sterigmatocystin, emodin, mycophenolic acid, alternariol, alternariol monomethyl ether, and tenuazonic acid. By far not all of the detected compounds are toxicologically relevant at their naturally occurring levels and are therefore of little or no health concern to consumers. Still, gaps in knowledge have been identified for several compounds. These gaps should be closed by the scientific community in the coming years to allow a proper risk assessment.

Occurrence, toxicity, bioaccessibility and mitigation strategies of beauvericin, a minor Fusarium mycotoxin

Emerging Fusarium mycotoxins include the toxic secondary metabolites fusaproliferin, enniatins, beauvericin (BEA), and moniliform. BEA is produced by some entomo- and phytopathogenic Fusarium species and occurs naturally on corn and corn-based foods and feeds infected by Fusarium spp. BEA has shown various biological activities (antibacterial, antifungal, and insecticidal) and possesses toxic activity, including the induction of apoptosis, increase cytoplasmic calcium concentration and lead to DNA fragmentation in mammalian cell lines. Cereals food processing has an important effect on mycotoxin stability, leading to less-contaminated food compared to the raw materials. Different industrial processes have shown to be effective practices to reduce BEA contents due to thermal food processing applied, such as cooking, boiling, baking, frying, roasting and pasteurization. Some studies demonstrated the capacity of lactic acid bacteria to reduce the presence of the BEA in model solution and in food chain through fermentation processes, modifying this mycotoxin in a less toxic derivate. Prebiotic and probiotic ingredient can modulate the bioaccessibility of BEA reducing the risk of intake of this minor Fusarium mycotoxin. This review summarizes the existing data on occurrence, toxicity and especially on BEA reduction strategies in food and feed such as chemical reduction, biocontrol and food processing.

Oxidative damage and disturbance of antioxidant capacity by zearalenone and its metabolites in human cells

Mycotoxin contamination of foods and feeds represent a serious problem worldwide. Zearalenone (ZEA) is a secondary metabolite produced by Fusarium species. This study explores oxidative cellular damage and intracellular defense mechanisms (enzymatic and non-enzymatic) in the hepatoma cell line HepG2 after exposure to ZEA and its metabolites (α-zearalenol, α-ZOL; β-zearalenol, β-ZOL). Our results demonstrated that HepG2 cells exposed to ZEA, α-ZOL or β-ZOL at different concentrations (0, 6.25, 12.5 and 25μM) showed: (i) elevated ROS levels (1.5- to 7-fold) based on the formation of the highly fluorescent 2',7'-dichlorofluorescein (DCF), (ii) increased DNA damage measured by the comet assay (9-45% higher), (iii) decreased GSH levels and CAT activity (decreased by 54%-25% and by 62%-25% for GSH and CAT, respectively) and (iv) increased GPx and SOD activities (increased by 50%-90% and by 26%-70%, respectively), compared to untreated cells. Our results suggest that mycotoxin-induced oxidative stress and damage may play a major role in the cytotoxic effects of ZEA and its metabolites. GSH and endogenous enzymes function together in protecting cells from ROS and the consequent damage after mycotoxin exposure. ZEA has a lower capacity to induce oxidative stress and damage in HepG2 cells than its metabolites at the tested concentrations.

Effect of Fusarium-Derived Metabolites on the Barrier Integrity of Differentiated Intestinal Porcine Epithelial Cells (IPEC-J2)

The human, animal and plant pathogen Fusarium, which contaminates agricultural commodities worldwide, produces numerous secondary metabolites. An example is the thoroughly-investigated deoxynivalenol (DON), which severely impairs gastrointestinal barrier integrity. However, to date, the toxicological profile of other Fusarium-derived metabolites, such as enniatins, beauvericin, moniliformin, apicidin, aurofusarin, rubrofusarin, equisetin and bikaverin, are poorly characterized. Thus we examined their effects—as metabolites alone and as metabolites in combination with DON—on the intestinal barrier function of differentiated intestinal porcine epithelial cells (IPEC-J2) over 72 h. Transepithelial electrical resistance (TEER) was measured at 24-h intervals, followed by evaluation of cell viability using neutral red (NR) assay. Enniatins A, A1, B and B1, apicidin, aurofusarin and beauvericin significantly reduced TEER. Moniliformin, equisetin, bikaverin and rubrofusarin had no effect on TEER. In the case of apicidin, aurofusarin and beauvericin, TEER reductions were further substantiated by the addition of otherwise no-effect DON concentrations. In all cases, viability was unaffected, confirming that TEER reductions were not due to compromised viability. Considering the prevalence of mycotoxin contamination and the diseases associated with intestinal barrier disruption, consumption of contaminated food or feed may have substantial health implications.

Toxicity of beauvericin on porcine oocyte maturation and preimplantation embryo development

Beauvericin (BEA) is one of many toxins produced by Fusarium species that contaminate feed materials. The aim of this study was to assess its effects on porcine oocyte maturation and preimplantation embryo development. Cumulus-oocyte-complexes and developing embryos were exposed to BEA and cultured until the blastocyst stage. Cumulus cells, oocytes and embryos were examined for viability, progesterone synthesis, multidrug resistance protein (MDR1), ATP content and gene expression related to MDR1 function, oxidative phosphorylation, steroidogenesis and apoptosis. BEA was toxic in embryos, oocytes and cumulus cells at concentrations exceeding 0.5μM, and embryos were most vulnerable after the four-cell stage. Since BEA exerted different effects in embryos, oocytes and cumulus cells, the toxic mechanism is suggested to involve different pathways. Currently there are no consistent data on adverse effects of BEA in pig farms.

Cytotoxic effects of zearalenone and its metabolites and antioxidant cell defense in CHO-K1 cells

Zearalenone (ZEA) and its metabolites (α-zearalenol; α-ZOL, β-zearalenol; β-ZOL) are secondary metabolites of Fusarium fungi that produce cell injury. The present study explores mycotoxin-induced cell damage and cellular protection mechanisms in CHO-K1 cells. Cytotoxicity has been determined by reactive oxygen species (ROS) production and DNA damage. ROS production was determined using the fluorescein assay and DNA strand breakage by comet assay. Intracellular protection systems were glutathione (GSH), glutathione peroxidase (GPx), catalase (CAT) and superoxide dismutase (SOD). The results demonstrated that all mycotoxins increased the ROS levels up to 5.3-fold the control levels in CHO-K1 cells. Zearalenone metabolites, but not ZEA, increased DNA damage 43% (α-ZOL) and 28% (β-ZOL) compared to control cells. The GSH levels decreased from 18% to 36%. The GPx and SOD activities respectively increased from 26% to 62% and from 23% to 69% in CHO-K1 cells, whereas CAT activity decreased from 14% to 52%. In addition, intracellular ROS production was induced by ZEA and its metabolites. The endogenous antioxidant system components GSH, GPx and SOD were activated against ZEA and its metabolites. These antioxidant system components thus could contribute to decrease cell injury by ZEA and its metabolites.

An in vitro investigation on the cytotoxic and nuclear receptor transcriptional activity of the mycotoxins fumonisin B1 and beauvericin

Fumonisin B1 (FB1) and beauvericin (BEA) are secondary metabolites of filamentous fungi, which under appropriate temperature and humidity conditions may develop on various foods and feeds. To date few studies have been performed to evaluate the toxicological and endocrine disrupting effects of FB1 and BEA. The present study makes use of various in vitro bioassays including; oestrogen, androgen, progestagen and glucocorticoid reporter gene assays (RGAs) for the study of nuclear receptor transcriptional activity, the thiazolyl blue tetrazolium bromide (MTT) assay to monitor cytotoxicity and high content analysis (HCA) for the detection of pre-lethal toxicity in the RGA and Caco-2 human colon adenocarcinoma cells. At the receptor level, 0.001-10μM BEA or FB1 did not induce any agonist responses in the RGAs. However at non-cytotoxic concentrations, an antagonistic effect was exhibited by FB1 on the androgen nuclear receptor transcriptional activity at 10μM and BEA on the progestagen and glucocorticoid receptors at 1μM. MTT analysis showed no decrease in cell viability at any concentration of FB1, whereas BEA showed a significant decrease in viability at 10μM. HCA analysis confirmed that the reduction in the progestagen receptor transcriptional activity at 1μM BEA was not due to pre-lethal toxicity. In addition, BEA (10μM) induced significant toxicity in both the TM-Luc (progestagen responsive) and Caco-2 cells.

Gastroprotective effect of 2-mercaptoethane sulfonate against acute gastric mucosal damage induced by ethanol

Gastric mucosal damage induced by ethanol is a serious medical problem. Recent evidences suggest that reactive oxygen species and inflammatory mediators play a key role in the destruction of gastric mucosa. The present study was aimed to evaluate the potential beneficial effect of MESNA (2-mercaptoethane sulfonate) against ethanol-induced gastric mucosal damage in mice. The animals were orally pretreated with vehicle or MESNA and then treated with acidified ethanol to induce gastric mucosal damage. One hour after ethanol ingestion mice were euthanized and stomach samples were collected for biochemical analysis. Macroscopic and histopathological evaluation of gastric mucosa showed that pretreatment with MESNA attenuated gastric lesions induced by ethanol. Administration of MESNA significantly increased glutathione content and superoxide dismutase and catalase activity in the gastric tissues. In addition, MESNA markedly reduced ethanol-induced lipid peroxidation, myeloperoxidase activity, tumor necrosis factor-alpha, interleukin (IL)-1β, IL-6, and monocyte chemotactic protein-1 levels. These findings suggest that the thiol-containing compound MESNA is able to decrease alcohol-induced oxidative stress and inflammation in the gastric tissue. It seems that MESNA may have a protective effect against ethanol-induced gastric mucosal damage.

Cytotoxic effects induced by patulin, sterigmatocystin and beauvericin on CHO-K1 cells

Mycotoxins are produced by different genera of fungi; mainly Aspergillus, Penicillium and Fusarium. The natural co-occurrence of beauvericin (BEA), patulin (PAT) and sterigmatocystin (STE) has been proved in feed and food commodities. This study investigates the cytotoxicity of individual and combined mycotoxins BEA, PAT and STE. The cytotoxicity on immortalized ovarian cells (CHO-K1) was evaluated using the MTT assay. After 24, 48 and 72 h, the IC50 values were 2.9 μM for PAT and ranged from 10.7 to 2.2 μM and from 25.0 to 12.5 μM for BEA and STE, respectively. Cytotoxic interactions were assayed by the isobologram method, which provides a combination index (CI) value as a quantitative measure of the three mycotoxin interaction's degree. Binary and tertiary combinations showed a dose dependent effect. At low fraction affected, mycotoxin combinations were synergetic; whereas, at higher fraction affected, the combinations showed additive effect. Our results indicate that the co-occurrence of low concentrations of mycotoxin in food may increase their toxic effects.