Influence of T-2 and HT-2 toxin on the blood-brain barrier in vitro: new experimental hints for neurotoxic effects

Human next-generation risk assessment of trichothecene toxicity

Trichothecenes are naturally occurring chemicals, produced by fungi, that can be found in contaminated crops. Trichothecenes have the potential to indirectly damage DNA and exacerbate genotoxic effects of genotoxicants. However, genotoxicity data for most trichothecenes are limited and data gaps remain. Here we use the γH2AX/pH3 assay to evaluate DNA damage in vitro of 13 trichothecenes. Three human cell lines (SH-SY5Y, ACHN, and HepG2) were exposed to each trichothecene (0.001-100 μM) to assess toxicity as models for the brain, kidney, and liver, respectively. Concentration-dependent induction of DNA damage, illustrated by γH2AX induction, was observed for all trichothecenes. In vitro-in vivo extrapolation (IVIVE) modeling was employed to support in vivo equivalent potency ranking and screen for risk potential. Diacetoxyscirpenol, T-2, and HT-2 had the highest genotoxic potency, notably in SH-SY5Y cells. Administered equivalent doses (AEDs) derived from IVIVE were compared against exposure data from French total diet studies to assess risk potential. AEDs derived for T-2 and HT-2 from the SH-SY5Y model were within 100-fold of exposure levels for infants aged one year or less. Overall, the potential for trichothecenes to damage DNA and higher exposures in infants highlights the need to investigate the cumulative effects across the broader trichothecene family.

The role of BTG2/PI3K/AKT pathway-mediated microglial activation in T-2 toxin-induced neurotoxicity

T-2 toxin is one of the mycotoxins widely distributed in human food and animal feed. Our recent work has shown that microglial activation may contribute to T-2 toxin-induced neurotoxicity. However, the molecular mechanisms involved need to be further clarified. To address this, we employed high-throughput transcriptome sequencing and found altered B cell translocation gene 2 (BTG2) expression levels in microglia following T-2 toxin treatment. It has been shown that altered BTG2 expression is involved in a range of neurological pathologies, but whether it's involved in the regulation of microglial activation is unclear. The aim of this study was to investigate the role of BTG2 in T-2 toxin-induced microglial activation. The results of animal experiments showed that T-2 toxin caused neurobehavioral disorders and promoted the expression of microglial BTG2 and pro-inflammatory activation of microglia in hippocampus and cortical, while microglial inhibitor minocycline inhibited these changes. The results of in vitro experiments showed that T-2 toxin enhanced BTG2 expression and pro-inflammatory microglial activation, and inhibited BTG2 expression weakened T-2 toxin-induced microglial activation. Moreover, T-2 toxin activated PI3K/AKT and its downstream NF-κB signaling pathway, which could be reversed after knock-down of BTG2 expression. Meanwhile, the PI3K inhibitor LY294002 also blocked this process. Therefore, BTG2 may be involved in T-2 toxin's ability to cause microglial activation through PI3K/AKT/NF-κB pathway.

Neurotoxic mechanisms of mycotoxins: Focus on aflatoxin B1 and T-2 toxin

Aflatoxin B1 (AFB1) and T-2 toxin are commonly found in animal feed and stored grain, posing a serious threat to human and animal health. Mycotoxins can penetrate brain tissue by compromising the blood-brain barrier, triggering oxidative stress and neuroinflammation, and leading to oxidative damage and apoptosis of brain cells. The potential neurotoxic mechanisms of AFB1 and T-2 toxin were discussed by summarizing the relevant research reports from the past ten years. AFB1 and T-2 toxin cause neuronal damage in the cerebral cortex and hippocampus, leading to synaptic transmission dysfunction, ultimately impairing the nervous system function of the body. The toxic mechanism is related to excessive reactive oxygen species (ROS), oxidative stress, mitochondrial dysfunction, apoptosis, autophagy, and an exaggerated inflammatory response. After passing through the blood-brain barrier, toxins can directly affect glial cells, alter the activation state of microglia and astrocytes, thereby promoting brain inflammation, disrupting the blood-brain barrier, and influencing the synaptic transmission process. We discussed the diverse effects of various concentrations of toxins and different modes of exposure on neurotoxicity. In addition, toxins can also cross the placental barrier, causing neurotoxic symptoms in offspring, as demonstrated in various species. Our goal is to uncover the underlying mechanisms of the neurotoxicity of AFB1 and T-2 toxin and to provide insights for future research, including investigating the impact of mycotoxins on interactions between microglia and astrocytes.

Review of neurotoxicity of T-2 toxin

T-2 toxin is a representative trichothecene that is widely detected in corn, wheat and other grain feeds. T-2 toxin has stable physical and chemical properties, making it difficult to remove from food and feed. Hence, T-2 toxin has become an unavoidable pollutant in food for humans and animals. T-2 toxin can enter brain tissue by crossing the blood-brain barrier and leads to congestion, swelling and even apoptosis of neurons. T-2 toxin poisoning can directly lead to clinical symptoms (anti-feeding reaction and decline of learning and memory function in humans and animals). Maternal T-2 toxin exposure also exerted toxic effects on the central nervous system of offspring. Oxidative stress is the core neurotoxicity mechanism underlying T-2 toxin poison. Oxidative stress-mediated apoptosis, mitochondrial oxidative damage and inflammation are all involved in the neurotoxicity induced by T-2 toxin. Thus, alleviating oxidative stress has become a potential target for relieving the neurotoxicity induced by T-2 toxin. Future efforts should be devoted to revealing the neurotoxic molecular mechanism of T-2 toxin and exploring effective therapeutic drugs to alleviate T-2 toxin-induced neurotoxicity.

Investigation of the effects of T-2 toxin in chicken-derived three-dimensional hepatic cell cultures

Despite being one of the most common contaminants of poultry feed, the molecular effects of T-2 toxin on the liver of the exposed animals are still not fully elucidated. To gain more accurate understanding, the effects of T-2 toxin were investigated in the present study in chicken-derived three-dimensional (3D) primary hepatic cell cultures. 3D spheroids were treated with three concentrations (100, 500, 1000 nM) of T-2 toxin for 24 h. Cellular metabolic activity declined in all treated groups as reflected by the Cell Counting Kit-8 assay, while extracellular lactate dehydrogenase activity was increased after 500 nM T-2 toxin exposure. The levels of oxidative stress markers malondialdehyde and protein carbonyl were reduced by the toxin, suggesting effective antioxidant compensatory mechanisms of the liver. Concerning the pro-inflammatory cytokines, IL-6 concentration was decreased, while IL-8 concentration was increased by 100 nM T-2 toxin exposure, indicating the multifaceted immunomodulatory action of the toxin. Further, the metabolic profile of hepatic spheroids was also modulated, confirming the altered lipid and amino acid metabolism of toxin-exposed liver cells. Based on these results, T-2 toxin affected cell viability, hepatocellular metabolism and inflammatory response, likely carried out its toxic effects by affecting the oxidative homeostasis of the cells.

Daucosterol confers protection against T-2 toxin induced blood-brain barrier toxicity through the PGC-1α-mediated defensive response in vitro and in vivo

T-2 toxin is a common environmental pollutant and contaminant in food and animal feed that represents a great challenge to human and animal' health throughout the world. Using natural compounds to prevent the detrimental effects of T-2 toxin represents an attractive strategy. Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) is a critical regulator in various cellular processes. Recently, PGC-1α activation has been reported to confer protection against neurological injuries. We aimed to identify a potent PGC-1α activator from plants as a chemopreventive compound and to demonstrate the efficacy of the compound in attenuating T-2 toxin-induced blood-brain barrier (BBB) toxicity. We identified daucosterol, which binds directly to the 71-74 (-1100 to -1000 bp) position of the second promoter of human PGC-1α by hydrogen bonding. An in vitro and in vivo T-2 toxin induced BBB injury model revealed that this compound can protect against this injury by increasing transepithelial/transendothelial electrical resistance, reducing sodium fluorescein (NaF) infiltration and increasing the expression of tight junction-related proteins (zonula occludens-1 (ZO-1), occludin (OCLN), claudin-5 (CLDN5)) expression. In conclusion, we identified daucosterol as representing a novel of PGC-1α activators and illustrated the mechanism of specific binding site. Furthermore, we have demonstrated the feasibility of using natural compounds targeting PGC-1α as a therapeutic approach to protect humans from environmental insults that may occur daily such as lipopolysaccharide.

Traditional and emerging Fusarium mycotoxins disrupt homeostasis of bovine mammary cells by altering cell permeability and innate immune function

High incidence of traditional and emerging Fusarium mycotoxins in cereal grains and silages can be a potential threat to feed safety and ruminants. Inadequate biodegradation of Fusarium mycotoxins by rumen microflora following ingestion of mycotoxin-contaminated feeds can lead to their circulatory transport to target tissues such as mammary gland. The bovine udder plays a pivotal role in maintaining milk yield and composition, thus, human health. However, toxic effects of Fusarium mycotoxins on bovine mammary gland are rarely studied. In this study, the bovine mammary epithelial cell line was used as an in-vitro model of bovine mammary epithelium to investigate effects of deoxynivalenol (DON), enniatin B (ENB) and beauvericin (BEA) on bovine mammary gland homeostasis. Results indicated that exposure to DON, ENB and BEA for 48 h significantly decreased cell viability in a concentration-dependent manner (P < 0.001). Exposure to DON at 0.39 μmol/L and BEA at 2.5 μmol/L for 48 h also decreased paracellular flux of FITC-40 kDa dextran (P < 0.05), whereas none of the mycotoxins affected transepithelial electrical resistance after 48 h exposure. The qPCR was performed for assessment of expression of gene coding tight junction (TJ) proteins, toll-like receptor 4 (TLR4) and cytokines after 4, 24 and 48 h of exposure. DON, ENB and BEA significantly upregulated the TJ protein zonula occludens-1, whereas markedly downregulated claudin 3 (P < 0.05). Exposure to DON at 1.35 μmol/L for 4 h significantly increased expression of occludin (P < 0.01). DON, ENB and BEA significant downregulated TLR4 (P < 0.05). In contrast, ENB markedly increased expression of cytokines interleukin-6 (IL-6) (P < 0.001), tumor necrosis factor α (TNF-a) (P < 0.05) and transforming growth factor-β (TGF-β) (P < 0.01). BEA significantly upregulated IL- 6 (P < 0.001) and TGF-β (P = 0.01), but downregulated TNF-α (P < 0.001). These results suggest that DON, ENB and BEA can disrupt mammary gland homeostasis by inducing cell death as well as altering its paracellular permeability and expression of genes involved in innate immune function.

Ochratoxin A and Citrinin Differentially Modulate Bovine Mammary Epithelial Cell Permeability and Innate Immune Function

Frequent detection of mycotoxins ochratoxin A (OTA) and citrinin (CIT) in ruminant feed and feedstuff can be a potential threat to feed safety, animal performance and health. Ineffective biodegradation of these mycotoxins by rumen microflora following ingestion of contaminated feeds can lead to their circulatory transport to tissues such as mammary gland as the result of their biodistribution throughout the body. The bovine mammary epithelium plays a pivotal role in maintaining milk yield and composition and contributes to innate immune defense of the udder. The present study is the first to investigate individual effects of OTA and CIT on barrier and innate immune functions of the bovine mammary epithelium using a bovine mammary epithelial cell line (MAC-T). Results indicated that OTA and CIT exposure for 48 h significantly decreased cell viability in a concentration-dependent manner (p < 0.05). A decrease in transepithelial electrical resistance and increase in paracellular flux of FITC-40 kDa dextran was significantly induced by OTA treatment (p < 0.05), but not by CIT after 48 h exposure. qPCR was performed for assessment of expression of tight-junction proteins, Toll-like receptor 4 (TLR4) and cytokines after 4, 24 and 48 h of exposure. Both OTA and CIT markedly downregulated expression of claudin 3 and occludin (p < 0.05), whereas CIT did not affect zonula occludens-1 expression. Expression of TLR4 was significantly upregulated by OTA (p < 0.001) but downregulated by CIT (p < 0.05) at 48 h. Expression of IL-6, TNF-a and TGF-β was significantly upregulated by OTA (p < 0.05), whereas IL-6 and TGF-β expression was downregulated by CIT (p < 0.01). These results suggest that OTA and CIT could potentially differentially modulate barrier and innate immune functions of mammary epithelium. The present study not only throws light on the individual toxicity of each mycotoxin on bovine mammary epithelium but also lays the foundation for future studies on the combined effects of the two mycotoxins.

NRF2/PGC-1α-mediated mitochondrial biogenesis contributes to T-2 toxin-induced toxicity in human neuroblastoma SH-SY5Y cells

The T-2 toxin is a highly toxic trichothecene mycotoxin that would cause serious toxicity in humans and animals. Recent studies suggest that the central nervous system (CNS) is susceptible to T-2 toxin, which can easily cross the blood-brain barrier, accumulate in brain tissues, and cause neurotoxicity. The growing evidence indicates that oxidative damage and mitochondrial dysfunction play a critical role in T-2 toxin-induced neurotoxicity, but the mechanisms are still poorly understood. Our present study showed that T-2 toxin decreased cell viability and increased lactate dehydrogenase leakage in human neuroblastoma SH-SY5Y cells in a concentration- and time-dependent manner. T-2 toxin elicited prominent oxidative stress and mitochondrial dysfunction, as evidenced by the promotion of cellular reactive oxygen species generation, disruption of the mitochondrial membrane potential, depletion of glutathione and reduction of the cellular ATP content. T-2 toxin impaired mitochondrial biogenesis, including decreased mitochondrial DNA copy number and affected the nuclear factor erythroid 2 related factor 2 (NRF2) / peroxisome proliferator-activated receptor γ coactivator 1 alpha (PGC-1α) pathway by upregulating NRF2 mRNA and protein expression while inhibiting the expression of PGC-1α, nuclear respiratory factor (NRF1) and mitochondrial transcription factor A (TFAM). NRF2 knockdown was found to significantly exacerbate T-2 toxin-induced cytotoxicity, oxidative stress, and mitochondrial dysfunction, as well as aggravate mitochondrial biogenesis impairment. NRF2 knockdown compromised T-2 toxin-induced upregulation of NRF2, but augmented the inhibition of PGC-1α, NRF1, and TFAM by T-2 toxin. Taken together, these findings suggest that T-2 toxin-induced oxidative stress and mitochondrial dysfunction in SH-SY5Y cells, at least in part by, NRF2/PGC-1α pathway-mediated mitochondrial biogenesis.

Betulinic acid attenuates cognitive dysfunction, oxidative stress, and inflammation in a model of T-2 toxin-induced brain damage

T-2 toxin is a mycotoxin that has harmful effects on the immune system and cognitive function. Betulinic acid (BA) is a plant-derived pentacyclic lupane-type triterpenoid which possesses a wide spectrum of bioactivities. The study was aimed to explore whether BA has a protective effect on cognitive impairment and oxidative stress caused by T-2 toxin. BA was suspended in 1% soluble starch by continuous intragastric administration for 14 days, then the brain damage in mice was induced by a single intraperitoneal injection of T-2 toxin (4 mg/kg). It was found that BA alleviated the reduction of discrimination index in T-2 toxin-treated mice, and enhanced dopamine (DA), 5-hydroxytryptamine (5-HT), and acetylcholine (ACH) levels of brain neurotransmitter. Meanwhile, BA pretreatment ameliorated oxidative stress through increase of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and glutathione (GSH) levels, and inhibition of the generation of reactive oxygen species (ROS) and malondialdehyde (MDA) in the brain of mice exposed to T-2 toxin. Moreover, BA reduced brain hemorrhage and ecchymosis, improved the mitochondrial morphology, enriched the number of organelles, and inhibited cell apoptosis in brain challenged with T-2 toxin. Furthermore, BA inhibited mRNA expression of pro-inflammatory cytokines such as interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α) as well as enhanced mRNA expression of anti-inflammatory cytokine such as IL-10 in the brain of T-2 toxin-triggered mice. Therefore, BA could improve the cognitive function, enhance the antioxidant capacity, and inhibit the secretion of proinflammatory cytokines in brain, thereby playing a preventive and protective role against brain damage caused by T-2 toxin.

Neuroimmune disruptions from naturally occurring levels of mycotoxins

Substantial pieces of evidence support the potential of exogenous toxins in disrupting neuroimmune homeostasis. It appears that mycotoxins are one of the noticeable sources of naturally occurring substances dysregulating the immune system, which involves the physiology of many organs, such as the central nervous system (CNS). The induction of inflammatory responses in microglial cells and astrocytes, the CNS resident cells with immunological characteristics, could interrupt the hemostasis upon even with low-level exposure to mycotoxins. The inevitable widespread occurrence of a low level of mycotoxins in foods and feed is likely increasing worldwide, predisposing individuals to potential neuroimmunological dysregulations. This paper reviews the current understanding of mycotoxins' neuro-immunotoxic features under low-dose exposure and the possible ways for detoxification and clearance as a perspective.

Efflux at the Blood-Brain Barrier Reduces the Cerebral Exposure to Ochratoxin A, Ochratoxin α, Citrinin and Dihydrocitrinone

Recent studies have implied that environmental toxins, such as mycotoxins, are risk factors for neurodegenerative diseases. To act directly as neurotoxins, mycotoxins need to penetrate or affect the integrity of the blood-brain barrier, which protects the mammalian brain from potentially harmful substances. As common food and feed contaminants of fungal origin, the interest in the potential neurotoxicity of ochratoxin A, citrinin and their metabolites has recently increased. Primary porcine brain capillary endothelial cells were used to investigate cytotoxic or barrier-weakening effects of ochratoxin A, ochratoxin α, citrinin and dihydrocitrinone. The transfer and transport properties of the mycotoxins across the barrier formed by porcine brain capillary endothelial cell monolayers were analysed using HPLC-MS/MS. High levels of Ochratoxin A caused cytotoxic and barrier-weakening effects, whereas ochratoxin α, citrinin and dihydrocitrinone showed no adverse effects up to 10 µM. Likely due to efflux transporter proteins, the transfer to the brain compartment was much slower than expected from their high lipophilicity. Due to their slow transfer across the blood-brain barrier, cerebral exposure of ochratoxin A, ochratoxin α, citrinin and dihydrocitrinone is low and neurotoxicity is likely to play a subordinate role in their toxicity at common physiological concentrations.

Effects of a Low Dose of T-2 Toxin on the Percentage of T and B Lymphocytes and Cytokine Secretion in the Porcine Ileal Wall

Plant materials used in the production of pig feed are frequently contaminated with mycotoxins. T-2 toxin is a secondary metabolite of selected Fusarium species, and it can exert a harmful influence on living organisms. Most mycotoxins enter the body via the gastrointestinal tract, and they can modulate the gut-associated lymphoid tissue (GALT) function. However, little is known about the influence of low T-2 toxin doses on GALT. Therefore, the aim of this study was to evaluate the effect of T-2 toxin administered at 50% of the lowest-observed-adverse-effect level (LOAEL) on the percentage of CD2+ T cells, CD4+ T helper cells, CD8+ cytotoxic T cells, CD4+CD8+ double-positive T cells, TCRγδ+ cells, CD5+CD8- B1 cells, and CD21+ B2 cells, and the secretion of proinflammatory (IFN-γ, IL-1β, IL-2, IL-12/23p40, IL-17A), anti-inflammatory, and regulatory (IL-4, IL-10, TGF-β) cytokines in the porcine ileal wall. The results of the study revealed that T-2 toxin disrupts the development of tolerance to food antigens by enhancing the secretion of proinflammatory and regulatory cytokines and decreasing the production of anti-inflammatory TGF-β. T-2 toxin triggered the cellular response, which was manifested by an increase in the percentage of CD8+ T cells and a decrease in the percentage of B2 and Tγδ lymphocytes.

Targeting HMGB1 inhibits T-2 toxin-induced neurotoxicity via regulation of oxidative stress, neuroinflammation and neuronal apoptosis

T-2 toxin, a food-derived mycotoxin, has been identified as a neurotoxin. Nonetheless, T-2 toxin-induced neuroinflammation has never been revealed. As an important therapeutic target for inflammatory diseases and cancers, the role of high mobility group B1 (HMGB1) in mycotoxin-mediated neurotoxicity remains a mystery. In current study, we found that PC12 cells were sensitive to trace amounts of T-2 toxin less than 12 ng/mL, distinguished by decreased cell viability and increased release of lactate dehydrogenase (LDH). Oxidative stress and mitochondrial damage were observed in PC12 cells, manifested as accumulation of oxidative stress products, up-regulation of Nrf2/HO-1 pathway and decrease of mitochondrial membrane potential (MMP), leading to mitochondria-dependent apoptosis. Meanwhile, we first discovered that tiny amounts of T-2 toxin triggered neuroinflammation directly, including raising the expression and translocation of NF-κB and promoting secretion of proinflammatory cytokines such as TNF-α, IL-6, IL-8 and IL-1β. Most interestingly, the increased of HMGB1 was detected both inside and outside the cells. Conversely, HMGB1 siRNA reduced T-2 toxin-mediated oxidative stress, apoptosis and neuroinflammatory outbreak, accompanied by lessened caspase-3 and caspase-9, and decreased secretion of pro-inflammatory cytokines. Taken together, T-2 toxin-stimulated PC12 cells simultaneously displayed apoptosis and inflammation, whereas HMGB1 played a critical role in these neurotoxic processes.

Quercetin mitigates the deoxynivalenol mycotoxin induced apoptosis in SH-SY5Y cells by modulating the oxidative stress mediators

Deoxynivalenol (DON) is Fusarium mycotoxin that is frequently found in many cereal-based foods, and its ingestion has a deleterious impact on human health. In this investigation, we studied the mechanism of DON-induced neurotoxicity and followed by cytoprotective efficacy of quercetin (QUE) in contradiction of DON-induced neurotoxicity through assessing the oxidative stress and apoptotic demise in the human neuronal model, i.e. SH-SY5Y cells. DON diminished the proliferation of cells in the manner of dose and time-dependent as revealed by cell viability investigations, i.e. MTT and lactate dehydrogenase assays. Additional studies, such as intracellular reactive oxygen species (ROS), lipid peroxidation (LPO), mitochondrial membrane potential (MMP), DNA damage, cell cycle, and neuronal biomarkers (amino acid decarboxylase, tyrosine hydroxylase, and brain-derived neurotrophic factor) demonstrated that DON induces apoptotic demise in neuronal cells through oxidative stress intermediaries. On another hand, pre-treatment of neuronal cells with 1 mM of quercetin (QUE) showed decent viability upon exposure to 100 µM of DON. In detailed studies demonstrated that QUE (1 mM) pre-treated cells show strong attenuation efficiency against DON-induced ROS generation, LPO, MMP loss, DNA impairment, cell cycle arrest, and down-regulation of neuronal biomarkers. The consequences of the investigation concluded that QUE mitigates the DON-induced stress viz., decreased ROS production and LPO generation, upholding MMP and DNA integrity and regulation of neuronal biomarker gene expression in SH-SY5Y cells.

Environmental toxins and Alzheimer's disease progression

Alzheimer's disease (AD) is the most common form of dementia, which causes progressive memory loss and cognitive decline. Effective strategies to treat or prevent remains one of the most challenging undertakings in the medical field. AD is a complex and multifactorial disease that involves several risk factors. Aging and genetic factors both play important roles in the onset of the AD, however; certain environmental factors have been reported to increase the risk of AD. Chronic exposure to toxins has been seen as an environmental factor that may increase the risk of developing a neurodegenerative disease such as AD. Exposure to metals and biotoxins produced by bacteria, molds, and viruses may contribute to the cognitive decline and pathophysiology associated with AD. Toxins may contribute to the pathology of the disease through various mechanisms such as deposition of amyloid-beta (Aβ) plaques and tangles in the brain, induction of apoptosis, inflammation, or oxidative damage. Here, we will review how toxins affect brain physiology with a focus on mechanisms by which toxins may contribute to the development and progression of AD. A better understanding of these mechanisms may help contribute towards the development of an effective strategy to slow the progression of AD.

Quality of Dietary Supplements Containing Plant-Derived Ingredients Reconsidered by Microbiological Approach

Dietary supplements cover a wide range of products, the most popular are those containing plant-based ingredients. Supplements are consumed by consumers of all ages as well as by both healthy and sick people. The lack of unified regulation in this sector increases the probability that supplements are poor chemical and microbiological quality and can be dangerous for patients. The aim of this paper is to highlight selected issues associated with the microbiological quality of dietary supplements containing plant materials. We focus on the most recent reports referring to bacterial and fungal contaminations as well as the presence of mycotoxins. Dietary supplements containing plant ingredients commonly show a variety of microbial contaminants, which might be crucial for consumer safety. They often contain microorganisms potentially pathogenic to humans. Metabolites produced by microorganisms may pose a threat to the health of consumers. Because of that, in this review, we emphasize the risk that may be associated with the lack of appropriate studies of the quality of the supplements.

An update on T-2 toxin and its modified forms: metabolism, immunotoxicity mechanism, and human exposure assessment

T-2 toxin is the most toxic trichothecene mycotoxin, and it exerts potent toxic effects, including immunotoxicity, neurotoxicity, and reproductive toxicity. Recently, several novel metabolites, including 3',4'-dihydroxy-T-2 toxin and 4',4'-dihydroxy-T-2 toxin, have been uncovered. The enzymes CYP3A4 and carboxylesterase contribute to T-2 toxin metabolism, with 3'-hydroxy-T-2 toxin and HT-2 toxin as the corresponding primary products. Modified forms of T-2 toxin, including T-2-3-glucoside, exert their immunotoxic effects by signaling through JAK/STAT but not MAPK. T-2-3-glucoside results from hydrolyzation of the corresponding parent mycotoxin and other metabolites by the intestinal microbiota, which leads to enhanced toxicity. Increasing evidence has shown that autophagy, hypoxia-inducible factors, and exosomes are involved in T-2 toxin-induced immunotoxicity. Autophagy promotes the immunosuppression induced by T-2 toxin, and a complex crosstalk between apoptosis and autophagy exists. Very recently, "immune evasion" activity was reported to be associated with this toxin; this activity is initiated inside cells and allows pathogens to escape the host immune response. Moreover, T-2 toxin has the potential to trigger hypoxia in cells, which is related to activation of hypoxia-inducible factor and the release of exosomes, leading to immunotoxicity. Based on the data from a series of human exposure studies, free T-2 toxin, HT-2 toxin, and HT-2-4-glucuronide should be considered human T-2 toxin biomarkers in the urine. The present review focuses on novel findings related to the metabolism, immunotoxicity, and human exposure assessment of T-2 toxin and its modified forms. In particular, the immunotoxicity mechanisms of T-2 toxin and the toxicity mechanism of its modified form, as well as human T-2 toxin biomarkers, are discussed. This work will contribute to an improved understanding of the immunotoxicity mechanism of T-2 toxin and its modified forms.

The neurotoxicity of trichothecenes T-2 toxin and deoxynivalenol (DON): Current status and future perspectives

During the last decade, the neurotoxicity of the trichothecenes T-2 toxin and deoxynivalenol (DON) has been a major concern, and many important findings have been reported on this topic. Through a summary of relevant research reports in recent years, we discuss the potential neurotoxic mechanisms of T-2 toxin and DON. In neuronal cells, T-2 toxin induces mitochondrial dysfunction and oxidative stress through a series of signalling pathways, including Nrf2/HO-1 and p53. This toxin crosses the blood-brain barrier (BBB) by altering permeability and induces oxidative stress responses, including ROS generation, lipid peroxidation, and protein carbonyl formation. Cellular metabolites (for example, HT-2 toxin) further promote neurotoxic effects. The type B trichothecene DON induces neuronal cell apoptosis via the MAPK and mitochondrial apoptosis pathways. This molecule induces inflammation of the central nervous system, increasing the expression of proinflammatory molecules. DON directly affects brain neurons and glial cells after passing through the BBB and affects the vitality and function of astrocytes and microglia. Exposure to trichothecenes alters brain dopamine levels, decreases ganglion area, and further induces brain damage. In this review, we mainly discuss the neurotoxicity of T-2 toxin and DON. However, our main goal was to reveal the potential mechanism(s) and offer new topics, including the potential of hypoxia-inducible factors, immune evasion, and exosomes, for future research in this context. This review should help elucidate the neurotoxic mechanism of trichothecenes and provides some potential inspiration for the follow-up study of neurotoxicity of mycotoxins.

Development of Brain Targeting Peptide Based MMP-9 Inhibiting Nanoparticles for the Treatment of Brain Diseases with Elevated MMP-9 Activity

Latent and active levels of cerebral matrix metalloproteinase 9 (MMP-9) are elevated in neurological diseases and brain injuries, contributing to neurological damage and poor clinical outcomes. This study aimed developing peptide-based nanoparticles with ability to cross the blood-brain-barrier (BBB) and inhibit MMP-9. Three amphiphilic peptides were synthesised containing brain-targeting ligands (HAIYPRH or CKAPETALC) conjugated with MMP-9 inhibiting peptide (CTTHWGFTLC) linked by glycine (spacer) at the N-terminus, and the peptide sequences were conjugated at the N- terminus to cholesterol. ¹⁹F NMR assay was developed to measure MMP-9 inhibition. Cell toxicity was evaluated by the LDH assay, and dialysis studies were conducted with/without fetal bovine serum. An in vitro model was employed to evaluate the ability of nanoparticles crossing the BBB. The amphiphilic peptide (Cholesterol-GGGCTTHWGFTLCHAIYPRH) formed nanoparticles (average size of 202.8 nm) with ability to cross the BBB model. MMP-9 inhibiting nanoparticles were non-toxic to cells, and reduced MMP-9 activity from kobs of 4.5 × 10^-6s^-1 to complete inhibition. Dialysis studies showed that nanoparticles did not disassemble by extreme dilution (40 folds), but gradually hydrolysed by serum enzymes. In conclusion, the MMP-9 inhibiting nanoparticles reduced the activity of MMP-9, with acceptable serum stability, minimal cell toxicity and ability to cross the in vitro BBB model.

Does low concentration mycotoxin exposure induce toxicity in HepG2 cells through oxidative stress?

The purpose of this study was to determine whether exposure to low concentrations of deoxynivalenol (DON), T-2 toxin (T-2) and patulin (PAT) in a human hepatocellular carcinoma cell line (HepG2) exerts toxic effects through mechanisms related to oxidative stress, and how cells deal with such exposure. Cell viability was determined by the MTT and protein content (PC) assays over 24, 48 and 72 h. The IC₅₀ values detected ranged from >10 to 2.53 ± 0.21 μM (DON), 0.050 ± 0.025 to 0.034 ± 0.007 μM (T-2) and 2.66 ± 0.66 to 1.17 ± 0.21 µM (PAT). The key players in oxidative stress are the generation of reactive oxygen species (ROS), lipid peroxidation (LPO) and mitochondrial membrane potential (MMP) dysfunction. The results obtained showed that PAT, DON and T-2 did not significantly increase LPO or ROS production with respect to the controls. Moreover, PAT and DON did not alter MMP, though T-2 increased MMP at the higher concentrations tested (17 and 34 nM). In conclusion, the exposure of HepG2 cells to nontoxic concentrations of T-2 condition them against subsequent cellular oxidative conditions induced by even higher concentrations of mycotoxin.

In Silico and In Vitro Studies of Mycotoxins and Their Cocktails; Their Toxicity and Its Mitigation by Silibinin Pre-Treatment

Mycotoxins found in randomly selected commercial milk thistle dietary supplement were evaluated for their toxicity in silico and in vitro. Using in silico methods, the basic physicochemical, pharmacological, and toxicological properties of the mycotoxins were predicted using ACD/Percepta. The in vitro cytotoxicity of individual mycotoxins was determined in mouse macrophage (RAW 264.7), human hepatoblastoma (HepG2), and human embryonic kidney (HEK 293T) cells. In addition, we studied the bioavailability potential of mycotoxins and silibinin utilizing an in vitro transwell system with differentiated human colon adenocarcinoma cells (Caco-2) simulating mycotoxin transfer through the intestinal epithelial barrier. The IC50 values for individual mycotoxins in studied cells were in the biologically relevant ranges as follows: 3.57-13.37 nM (T-2 toxin), 5.07-47.44 nM (HT-2 toxin), 3.66-17.74 nM (diacetoxyscirpenol). Furthermore, no acute toxicity was obtained for deoxynivalenol, beauvericin, zearalenone, enniatinENN-A, enniatin-A1, enniatin-B, enniatin-B1, alternariol, alternariol-9-methyl ether, tentoxin, and mycophenolic acid up to the 50 nM concentration. The acute toxicity of these mycotoxins in binary combinations exhibited antagonistic effects in the combinations of T-2 with DON, ENN-A1, or ENN-B, while the rest showed synergistic or additive effects. Silibinin had a significant protective effect against both the cytotoxicity of three mycotoxins (T-2 toxin, HT-2 toxin, DAS) and genotoxicity of AME, AOH, DON, and ENNs on HEK 293T. The bioavailability results confirmed that AME, DAS, ENN-B, TEN, T-2, and silibinin are transported through the epithelial cell layer and further metabolized. The bioavailability of silibinin is very similar to mycotoxins poor penetration.

Endocrine Disruptors Induced Distinct Expression of Thyroid and Estrogen Receptors in Rat versus Mouse Primary Cerebellar Cell Cultures

The endocrine system of animals consists of fine-tuned self-regulating mechanisms that maintain the hormonal and neuronal milieu during tissue development. This complex system can be influenced by endocrine disruptors (ED)—substances that can alter the hormonal regulation even in small concentrations. By now, thousands of substances—either synthesized by the plastic, cosmetic, agricultural, or medical industry or occurring naturally in plants or in polluted groundwater—can act as EDs. Their identification and testing has been a hard-to-solve problem; Recent indications that the ED effects may be species-specific just further complicated the determination of biological ED effects. Here we compare the effects of bisphenol-A, zearalenone, and arsenic (well-known EDs) exerted on mouse and rat neural cell cultures by measuring the differences of the ED-affected neural estrogen- and thyroid receptors. EDs alters the receptor expression in a species-like manner detectable in the magnitude as well as in the nature of biological responses. It is concluded that the interspecies differences (or species specificity) in ED effects should be considered in the future testing of ED effects.

Chronic neurodegeneration by aflatoxin B1 depends on alterations of brain enzyme activity and immunoexpression of astrocyte in male rats

Aflatoxin B1 poses the greatest risk among the mycotoxins to target-organisms particularly human, however, no studies addressed the neurotoxicity of chronic exposure of aflatoxin. The oral dose level 1/600th of LD50 for 30, 60, and 90 days was used for three aflatoxin groups, respective to negative and vehicle control groups. Activity levels of brain antioxidants viz: superoxide dismutase, catalase, glutathione, and glutathione peroxidase significantly decreased in the three experimental durations in time-dependent trend, in contrast, lipid peroxidation showed a significant increase compared to controls. Significantly, chronic-dependent increase trend was noticed in the AF60 and AF90 group for acid phosphatase (16.1%, 35.2%), alkaline phosphatase (32.1%, 50.8%), aspartate aminotransferase (38.7%, 120.0%) and lactate dehydrogenase (30.6%, 42.1%) activities, respectively. However, a significant 23.7% decrease in the brain creatine kinase activity following 90 days of AFB1administration. Chronic administration of aflatoxin also causes alterations in activities of protein carbonyl with a maximum increase (twofold) after 90 days. Further, histopathological and immunohistochemical results confirmed time-related vasodilation, necrosis and astrocytes gliosis by high glial fibrillary acidic protein immunostaining in response to AFB1. These findings infer that long-term exposure to AFB1 results in several pathophysiological circumstances in a duration-dependent manner concerning neurodegeneration especially Alzheimer's disease.

T-2 toxin neurotoxicity: role of oxidative stress and mitochondrial dysfunction

Mycotoxins are highly diverse secondary metabolites produced in nature by a wide variety of fungi. Mycotoxins cause animal feed and food contamination, resulting in mycotoxicosis. T-2 toxin is one of the most common and toxic trichothecene mycotoxins. For the last decade, it has garnered considerable attention due to its potent neurotoxicity. Worryingly, T-2 toxin can cross the blood-brain barrier and accumulate in the central nervous system (CNS) to cause neurotoxicity. This review covers the current knowledge base on the molecular mechanisms of T-2 toxin-induced oxidative stress and mitochondrial dysfunction in the CNS. In vitro and animal data have shown that induction of reactive oxygen species (ROS) and oxidative stress plays a critical role during T-2 toxin-induced neurotoxicity. Mitochondrial dysfunction and cascade signaling pathways including p53, MAPK, Akt/mTOR, PKA/CREB and NF-κB contribute to T-2 toxin-induced neuronal cell death. T-2 toxin exposure can also result in perturbations of mitochondrial respiratory chain complex and mitochondrial biogenesis. T-2 toxin exposure decreases the mitochondria unfolded protein response and dampens mitochondrial energy metabolism. Antioxidants such as N-acetylcysteine (NAC), activation of Nrf2/HO-1 and autophagy have been shown to provide a protective effect against these detrimental effects. Clearly, translational research and the discovery of effective treatment strategies are urgently required against this common food-borne threat to human health and livestock.

Species-specific models in toxicology: in vitro epithelial barriers

Species-specific in vitro epithelial barriers represent interesting predictive tools for risk assessment evaluation in toxicological studies. Moreover, these models could be applied either as stand-alone methods for the study of absorption, bioavailability, excretion, transport, effects of xenobiotics, or through an Integrated Testing Strategy. The aim of this review is to give a comprehensive overview of in vitro species-specific epithelial barrier models from bovine, dog and swine. Bovine mammary epithelial barrier as a fundamental instrument for the evaluation of the toxicant excretion, the blood brain barrier as a useful first approach in toxicological and pharmacological studies, the porcine intestinal barrier, the canine skin barrier, and finally the pulmonary barrier from bovine and swine species are described in this review.

T-2 toxin downregulates LHCGR expression, steroidogenesis, and cAMP level in human cumulus granulosa cells

Our goals were to investigate whether environmentally relevant doses of T-2 toxin can affect human ovarian granulosa cells' function and to reveal the potential mechanism of T-2 toxin's action. Results showed that T-2 toxin strongly attenuated luteinizing hormone/choriogonadotropin receptor (LHCGR) mRNA expression in follicle-stimulating hormone (FSH)-stimulated human cumulus granulosa cells. Addition of human chorionic gonadotropin was not able to elicit maximal response of ovulatory genes amphiregulin, epiregulin, and progesterone receptor. T-2 toxin reduced mRNA levels of CYP19A1 and steroidogenic acute regulatory protein (STAR) and lowered FSH-stimulated estradiol and progesterone production. Mechanistic experiments demonstrated that T-2 toxin decreased FSH-stimulated cyclic adenosine monophosphate (cAMP) production. Addition of total PDE inhibitor 3-isobutyl-1-methylxanthine prevented T-2 toxin's action on LHCGR, STAR, and CYP19A1 mRNA expression in FSH-stimulated human cumulus granulosa cells. Furthermore, T-2 toxin partially decreased 8-bromoadenosine 3'5'-cyclic monophosphate (8-Br-cAMP)-stimulated LHCGR and STAR, but did not affect 8-Br-cAMP-stimulated CYP19A1 mRNA expression in human cumulus granulosa cells. Overall, our data indicate that environmentally relevant dose of T-2 toxin decreases steroidogenesis and ovulatory potency in human cumulus granulosa cells probably through activation of PDE, thus posing a significant risk for female fertility.

Transport of enniatin B and enniatin B1 across the blood-brain barrier and hints for neurotoxic effects in cerebral cells

Enniatins are common contaminants of food and feed and belong to the group of the "emerging" mycotoxins, which are produced by various Fusarium species. Although a wide range of toxic effects, like antibacterial, antifungal, insecticidal and cytotoxic properties, have been described in vitro, so far, no cases of mycotoxicosis connected to enniatins in vivo are reported. Among this group of mycotoxins, enniatin B and enniatin B1 are the most prevalent compounds and therefore are present in the human diet. Enniatins can reach systemic circulation, thus, the investigation of possible neurotoxic effects is of importance. Different cerebral cells were used to address effects on cell death having an impact on the blood-brain barrier. The influence of enniatin B and enniatin B1 on cellular viability was examined via Cell Counting kit-8 assay (CCK-8) in three different cell types of the blood-brain barrier: porcine brain capillary endothelial cells (PBCEC), human brain microvascular endothelial cells (HBMEC) and human astrocytoma cells (CCF-STTG1). CCF-STTG1 cells were more sensitive to enniatin B (IC50 = 8.9 μM) and enniatin B1 (IC50 = 4.4 μM) than both endothelial cell types. In CCF-STTG1 cells, caspase-3 activation and lactate dehydrogenase (LDH) release were evaluated. Both compounds did not induce any LDH release and only enniatin B increased caspase-3 activity as a marker for apoptosis. The transport kinetics of enniatin B and enniatin B1 across the blood-brain barrier in vitro were evaluated using PBCEC, cultivated on Transwell® filter inserts. Analysis of the apical and the basolateral compartment by high performance liquid chromatography-mass spectrometry revealed high influx rates for enniatin B and enniatin B1. Thus, both compounds can reach the brain parenchyma where neurotoxic effects cannot be ruled out.

Comparative Analysis of Zearalenone Effects on Thyroid Receptor Alpha (TRα) and Beta (TRβ) Expression in Rat Primary Cerebellar Cell Cultures

Thyroid receptors play an important role in postnatal brain development. Zearalenone (ZEN), a major mycotoxin of Fusarium fungi, is well known to cause serious health problems in animals and humans through various mechanisms, including the physiological pathways of thyroid hormone (TH). In the present study, we aimed to investigate the expression of thyroid receptors α (TRα) and β (TRβ) in primary cerebellar neurons in the presence or absence of glia and following ZEN treatment, using quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and Western blot. Primary cerebellar granule cells were treated with low doses of ZEN (0.1 nM) in combination with physiologically relevant concentrations of l-thyroxine (T4), 3,3′,5-triiodo-l-thyronine (T3) and 17β-estradiol (E2). Expression levels of TRα and TRβ at mRNA and protein levels were slightly modified by ZEN administered alone; however, along with thyroid and steroid hormones, modelling the physiological conditions, expression levels of TRs varied highly depending on the given treatment. Gene expression levels were also highly modulated by the presence or absence of glial cells, with mostly contrasting effects. Our results demonstrate divergent transcriptional and translational mechanisms involved in the expression of TRs implied by ZEN and hormonal milieu, as well as culturing conditions.

Effects of T-2 and Fumonisin B1 combined treatment on in vitro mouse embryo development and blastocyst quality

In the temperate region, most common mycotoxins are members of fusariotoxins. It often happens that food and forage are contaminated with two or more fusariotoxins at the same time. Effects of co-contamination are poorly documented, especially in the field of reproduction. The aim of our study was to assess the combined effect of the two common fusariotoxins, T-2 toxin (T-2) and Fumonisin B1 on early mouse embryo development in vitro. Embryo culture media contained either (1) 0.5 ng/ml T-2; 1, 2, or 10 ng/ml FB1 (group A, B, and C, respectively); or (2) 0.5 ng/ml T-2 and 1, 2, or 10 ng/ml FB1 (group TA, TB, and TC, respectively). Developmental rate, blastocoel expansion, cell number, and micronucleus rate were measured following 96 h culture. Although the developmental rate was similar to the control group (86.43% vs. 83.33, 78.79, 85.98, and 86.67%, respectively) in the case of single toxin treatments, the combined treatments induced significant decreases (14.5, 33.6, and 22.8% in TA, TB, and TC, respectively). The proportion of late blastocysts was lower in all treatments compared to control (83.6% vs. 0–83.6%). Combined treatment resulted in a significantly lower proportion of late blastocysts (25% in TA and 0% in TB and TC). Cell numbers decreased in all toxin-treated groups with a higher rate after combined treatments. No differences were detected in the micronucleus rate in the single or combined treatments compared to control. Our study shows that T-2 and FB1 toxins do not necessarily decrease the developmental rate, but co-contamination results in a significantly lower blastocyst rate and disturbs the blastocoel expansion as well. One possible explanation of this observation could be that the presence of two mycotoxins in the culture media intensifies their negative effects. All toxin treatments decreased the cell number in the blastocysts and this negative effect was more expressed after combined treatment.

The Impact of T-2 Toxin on Vasoactive Intestinal Polypeptide-Like Immunoreactive (VIP-LI) Nerve Structures in the Wall of the Porcine Stomach and Duodenum

T-2 toxin is a secondary metabolite of some Fusarium species. It is well-known that this substance can harmfully impact living organisms. Among others, thanks to the ability of crossing the blood–brain barrier, T-2 toxin can affect the central nervous system. Mycotoxins mostly get into the organism through the digestive tract; therefore, first of all they have to break the intestinal barrier, wherein the important component is the enteric nervous system (ENS). However, knowledge about the impact of T-2 toxin on the ENS is rather scant. As a result of the influence of various physiological and pathological agents, ENS can undergo adaptive and reparative processes which manifest as changes in the immunoreactivity of perikaryons for neuronal active substances. So, the aim of the present investigation was to study how low doses of T-2 toxin affect vasoactive intestinal polypeptide-like immunoreactive (VIP-LI) nervous structures in the ENS of the porcine stomach and duodenum. Obtained results have shown that T-2 toxin causes an percentage increase of VIP-LI nerve cells and nerve fibers in every enteric plexus in both fragments of gastrointestinal tract studied. This shows that even low doses of T-2 toxin can have an influence on living organisms.

T-2 mycotoxin treatment of newborn rat pups does not significantly affect nervous system functions in adulthood

T-2 toxin is primarily produced by Fusarium sp. abundant under temperate climatic conditions. Its main harmful effect is the inhibition of protein synthesis. Causing oxidative stress, it also promotes lipid peroxidation and changes plasma membrane phospholipid composition; this may lead to nervous system alterations. The aim of the present study was to examine whether a single dose of T-2 toxin administered at newborn age has any long-lasting effects on nervous system functions. Rat pups were treated on the first postnatal day with a single intraperitoneal dose of T-2 toxin (0.2 mg/bwkg). Body weight of treated pups was lower during the second and third week of life, compared to littermates; later, weight gain was recovered. At young adulthood, behavior was tested in the open field, and no difference was observed between treated and control rats. Field potential recordings from somatosensory cortex and hippocampus slices did not reveal any significant difference in neuronal network functions. In case of neocortical field EPSP, the shape was slightly different in treated pups. Long-term synaptic plasticity was also comparable in both groups. Seizure susceptibility of the slices was not different, either. In conclusion, T-2 toxin did not significantly affect basic nervous system functions at this dose.

T-2 toxin-induced toxicity in neuroblastoma-2a cells involves the generation of reactive oxygen, mitochondrial dysfunction and inhibition of Nrf2/HO-1 pathway

The molecular mechanisms of T-2 mycotoxin induced neurotoxicity remains enigmatic. In the present study we show that T-2 toxin induced neurotoxicity in mouse neuroblastoma2a (N2a) cells is both dose- and time-dependent and is associated with oxidative stress, mitochondrial dysfunction and apoptosis. T-2 toxin treatment of N2a cells at 10, 20, 40 and 80 ng/mL for 24 h significantly up-regulated the mRNA expression of p53, Bax, and caspase-8 and down-regulated the expression of Nrf2 and HO-1 mRNA and protein expression. Activation of caspases-8, -9 and -3 was also evident in a concentration-dependent manner. Pre-treatment of the cells with the antioxidant N-acetyl-cysteine markedly suppressed T-2 toxin-induced neurotoxicity and caspase activation. Conversely, pre-treatment of the cells with the Nrf2 inhibitor brusatol or the HO-1 inhibitor zinc protoporphyrin IX, enhanced T-2 toxin induced neurotoxicity and increased the activation of caspase-9 and -3. Taken together, these novel findings suggest that T-2 toxin-induced neurotoxicity in N2a cells involves oxidative stress, mitochondrial dysfunction and apoptosis via the inhibition of the Nrf2/HO-1 and activation of p53 pathway. The present study highlights the potential of developing much needed pharmacological interventions to prevent T-2 toxin neurotoxicity.

Antioxidant agents against trichothecenes: new hints for oxidative stress treatment

Trichothecenes are a group of mycotoxins mainly produced by fungi of genus Fusarium. Due to high toxicity and widespread dissemination, T-2 toxin and deoxynivalenol (DON) are considered to be the most important compounds of this class. Trichothecenes generate free radicals, including reactive oxygen species (ROS), which induce lipid peroxidation, decrease levels of antioxidant enzymes, and ultimately lead to apoptosis. Consequently, oxidative stress is an active area of research on the toxic mechanisms of trichothecenes, and identification of antioxidant agents that could be used against trichothecenes is crucial for human health. Numerous natural compounds have been analyzed and have shown to function very effectively as antioxidants against trichothecenes. In this review, we summarize the molecular mechanisms underlying oxidative stress induced by these compounds, and discuss current knowledge regarding such antioxidant agents as vitamins, quercetin, selenium, glucomannan, nucleotides, antimicrobial peptides, bacteria, polyunsaturated fatty acids, oligosaccharides, and plant extracts. These products inhibit trichothecene-induced oxidative stress by (1) inhibiting ROS generation and induced DNA damage and lipid peroxidation; (2) increasing antioxidant enzyme activity; (3) blocking the MAPK and NF-κB signaling pathways; (4) inhibiting caspase activity and apoptosis; (5) protecting mitochondria; and (6) regulating anti-inflammatory actions. Finally, we summarize some decontamination methods, including bacterial and yeast biotransformation and degradation, as well as mycotoxin-binding agents. This review provides a comprehensive overview of antioxidant agents against trichothecenes and casts new light on the attenuation of oxidative stress.

T-2 toxin induces cytotoxicity and disrupts tight junction barrier in SerW3 cells

T-2 toxin, which is produced in grain and grain products as a secondary metabolite by Fusarium species, is also potentially dangerous for human health. Up to date, no study was reported the cytotoxicity of T-2 toxin on SerW3 cells in the perspective of junctional barriers. This study focused on revealing the cytotoxic effects of T-2 on Sertoli cells associated with cell junctional barriers. In the present study, SerW3 cells were exposed to T-2 toxin at 12, 120 and 1200ng/ml doses for 24 and 48h. Cytotoxicity tests including cell viability (MTT), lactate dehydrogenase (LDH) cytotoxicity test and trypan blue exclusion assay were performed. Occludin, ZO-1, N-cadherin and β-catenin were immunolabelled, expressions of occludin and N-cadherin were determined by western blotting. SerW3 cell barrier integrity was measured by transepithelial electrical resistance (TEER). Cytotoxicity caused by T-2 toxin increased in a dose dependent manner, expressions of proteins and TEER measurement decreased. This study may underlie the early targets of T-2 toxin on SerW3 cells mimicking blood-testis barrier in vitro.

The Influence of Low Doses of Zearalenone and T-2 Toxin on Calcitonin Gene Related Peptide-Like Immunoreactive (CGRP-LI) Neurons in the ENS of the Porcine Descending Colon

The enteric nervous system (ENS) can undergo adaptive and reparative changes in response to physiological and pathological stimuli. These manifest primarily as alterations in the levels of active substances expressed by the enteric neuron. While it is known that mycotoxins can affect the function of the central and peripheral nervous systems, knowledge about their influence on the ENS is limited. Therefore, the aim of the present study was to investigate the influence of low doses of zearalenone (ZEN) and T-2 toxin on calcitonin gene related peptide-like immunoreactive (CGRP-LI) neurons in the ENS of the porcine descending colon using a double immunofluorescence technique. Both mycotoxins led to an increase in the percentage of CGRP-LI neurons in all types of enteric plexuses and changed the degree of co-localization of CGRP with other neuronal active substances, such as substance P, galanin, nitric oxide synthase, and cocaine- and amphetamine-regulated transcript peptide. The obtained results demonstrate that even low doses of ZEN and T-2 can affect living organisms and cause changes in the neurochemical profile of enteric neurons.

T2 Toxin-Induced Changes in Cocaine- and Amphetamine-Regulated Transcript (CART)-Like Immunoreactivity in the Enteric Nervous System Within Selected Fragments of the Porcine Digestive Tract

T-2 toxin is a mycotoxin produced by some Fusarium species, which may affect the synthesis of DNA and RNA and causes various pathological processes. Till now, the influence of T-2 toxin on the enteric nervous system (ENS) located in the wall of gastrointestinal tract has not been studied. On the other hand, cocaine- and amphetamine-regulated transcript (CART) is one of enteric neuronal factors, whose exact functions in the intestines still remain not fully explained. The present study describes the influence of low doses of T-2 toxin on CART-positive neuronal structures in porcine stomach, duodenum, and descending colon. Distribution of CART was studied using the double immunofluorescence technique in the plexuses of the ENS, as well as in nerve fibers within the circular muscle and mucosal layers of porcine gastrointestinal tract. Generally, after T-2 toxin administration the greater number of CART-LI structures were studied, but intensity of changes depended on part of the ENS and digestive tract fragment studied. The obtained results show that even low doses of T-2 toxin may change the expression of CART in the ENS.

Exposure to HT-2 toxin causes oxidative stress induced apoptosis/autophagy in porcine oocytes

T-2 toxin is a main type A trichothecene mycotoxin which is the most toxic trichothecence. T-2 toxin has posed various toxic effects on human and animals in vigorous cell proliferation tissues like lymphoid, hematopoietic and gastrointestinal tissues, while HT-2 toxin is the major metabolite which is deacetylated by T-2 toxin. In this study, we focused on the toxic effects of HT-2 on porcine oocyte maturation. We treated the porcine oocyte with HT-2 toxin in vitro, and we first found that HT-2 treatment inhibited porcine oocyte polar body extrusion and cumulus cell expansion. We observed the disrupted meiotic spindle morphology after treatment, which might be due to the reduced p-MAPK protein level. Actin distribution was also disturbed, indicating that HT-2 affects cytoskeleton of porcine oocytes. We next explored the causes for the failure of oocyte maturation after HT-2 treatment. We found that HT-2 treated oocytes showed the increased ROS level, which indicated that oxidative stress had occurred. We also detected autophagy as well as early apoptosis in the treatment oocytes. Due to the fact that oxidative stress could induced apoptosis, our results indicated that HT-2 toxin caused oxidative stress induced apoptosis and autophagy, which further affected porcine oocyte maturation.

No Association between Mycotoxin Exposure and Autism: A Pilot Case-Control Study in School-Aged Children

Evaluation of environmental risk factors in the development of autism spectrum disorder (ASD) is needed for a more complete understanding of disease etiology and best approaches for prevention, diagnosis, and treatment. A pilot experiment in 54 children (n = 25 ASD, n = 29 controls; aged 12.4 ± 3.9 years) screened for 87 urinary mycotoxins via liquid chromatography-tandem mass spectrometry to assess current exposure. Zearalenone, zearalenone-4-glucoside, 3-acetyldeoxynivalenol, and altenuene were detected in 9/54 (20%) samples, most near the limit of detection. No mycotoxin/group of mycotoxins was associated with ASD-diagnosed children. To identify potential correlates of mycotoxin presence in urine, we further compared the nine subjects where a urinary mycotoxin was confirmed to the remaining 45 participants and found no difference based on the presence or absence of mycotoxin for age (t-test; p = 0.322), gender (Fisher’s exact test; p = 0.456), exposure or not to selective serotonin reuptake inhibitors (Fisher’s exact test; p = 0.367), or to other medications (Fisher’s exact test; p = 1.00). While no positive association was found, more sophisticated sample preparation techniques and instrumentation, coupled with selectivity for a smaller group of mycotoxins, could improve sensitivity and detection. Further, broadening sampling to in utero (mothers) and newborn-toddler years would cover additional exposure windows.

Critical review evaluating the pig as a model for human nutritional physiology

The present review examines the pig as a model for physiological studies in human subjects related to nutrient sensing, appetite regulation, gut barrier function, intestinal microbiota and nutritional neuroscience. The nutrient-sensing mechanisms regarding acids (sour), carbohydrates (sweet), glutamic acid (umami) and fatty acids are conserved between humans and pigs. In contrast, pigs show limited perception of high-intensity sweeteners and NaCl and sense a wider array of amino acids than humans. Differences on bitter taste may reflect the adaptation to ecosystems. In relation to appetite regulation, plasma concentrations of cholecystokinin and glucagon-like peptide-1 are similar in pigs and humans, while peptide YY in pigs is ten to twenty times higher and ghrelin two to five times lower than in humans. Pigs are an excellent model for human studies for vagal nerve function related to the hormonal regulation of food intake. Similarly, the study of gut barrier functions reveals conserved defence mechanisms between the two species particularly in functional permeability. However, human data are scant for some of the defence systems and nutritional programming. The pig model has been valuable for studying the changes in human microbiota following nutritional interventions. In particular, the use of human flora-associated pigs is a useful model for infants, but the long-term stability of the implanted human microbiota in pigs remains to be investigated. The similarity of the pig and human brain anatomy and development is paradigmatic. Brain explorations and therapies described in pig, when compared with available human data, highlight their value in nutritional neuroscience, particularly regarding functional neuroimaging techniques.

Mycotoxins modify the barrier function of Caco-2 cells through differential gene expression of specific claudin isoforms: Protective effect of illite mineral clay

Aflatoxin B1 (AFB1), fumonisin B1 (FB1), ochratoxin A (OTA) and T-2 toxin (T2) are mycotoxins that commonly contaminate the food chain and cause various toxicological effects. Their global occurrence is regarded as an important risk factor for human and animal health. In this study, the results demonstrate that, in human Caco-2 cells, AFB1, FB1, OTA and T2 origin cytotoxic effects, determining cell viability through MTT assay and LDH leakage, and decrease trans-epithelial electrical resistance (TEER). The decrease in barrier properties is concomitant with a reduction in the expression levels of the tight junction constituents claudin-3, claudin-4 and occludin. The protective effect of mineral clays (diosmectite, montmorillonite and illite) on alterations in cell viability and epithelial barrier function induced by the mycotoxins was also evaluated. Illite was the best clay to prevent the mycotoxin effects. Illite plus mycotoxin co-treatment completely abolished AFB1 and FB1-induced cytotoxicity. Also, the decreases in the gene expression of claudins and the reduction of TEER induced by mycotoxins were reversed by the illite plus mycotoxin co-treatment. In conclusion, these results demonstrated that mycotoxins AFB1, FB1, T2 and OTA disrupt the intestinal barrier permeability by a mechanism involving reduction of claudin isoform expressions, and illite counteracts this disruption.

Overnutrition Determines LPS Regulation of Mycotoxin Induced Neurotoxicity in Neurodegenerative Diseases

Chronic neurodegenerative diseases are now associated with obesity and diabetes and linked to the developing and developed world. Interests in healthy diets have escalated that may prevent neurodegenerative diseases such as Parkinson's and Alzheimer's disease. The global metabolic syndrome involves lipoprotein abnormalities and insulin resistance and is the major disorder for induction of neurological disease. The effects of bacterial lipopolysaccharides (LPS) on dyslipidemia and NAFLD indicate that the clearance and metabolism of fungal mycotoxins are linked to hypercholesterolemia and amyloid beta oligomers. LPS and mycotoxins are associated with membrane lipid disturbances with effects on cholesterol interacting proteins, lipoprotein metabolism, and membrane apo E/amyloid beta interactions relevant to hypercholesterolemia with close connections to neurological diseases. The influence of diet on mycotoxin metabolism has accelerated with the close association between mycotoxin contamination from agricultural products such as apple juice, grains, alcohol, and coffee. Cholesterol efflux in lipoproteins and membrane cholesterol are determined by LPS with involvement of mycotoxin on amyloid beta metabolism. Nutritional interventions such as diets low in fat/carbohydrate/cholesterol have become of interest with relevance to low absorption of lipophilic LPS and mycotoxin into lipoproteins with rapid metabolism of mycotoxin to the liver with the prevention of neurodegeneration.

Blood-Brain Barrier Effects of the Fusarium Mycotoxins Deoxynivalenol, 3 Acetyldeoxynivalenol, and Moniliformin and Their Transfer to the Brain

BACKGROUND

Secondary metabolites produced by Fusarium fungi frequently contaminate food and feed and have adverse effects on human and animal health. Fusarium mycotoxins exhibit a wide structural and biosynthetic diversity leading to different toxicokinetics and toxicodynamics. Several studies investigated the toxicity of mycotoxins, focusing on very specific targets, like the brain. However, it still remains unclear how fast mycotoxins reach the brain and if they impair the integrity of the blood-brain barrier. This study investigated and compared the effects of the Fusarium mycotoxins deoxynivalenol, 3-acetyldeoxynivalenol and moniliformin on the blood-brain barrier. Furthermore, the transfer properties to the brain were analyzed, which are required for risk assessment, including potential neurotoxic effects.

METHODS

Primary porcine brain capillary endothelial cells were cultivated to study the effects of the examined mycotoxins on the blood-brain barrier in vitro. The barrier integrity was monitored by cellular impedance spectroscopy and 14C radiolabeled sucrose permeability measurements. The distribution of the applied toxins between blood and brain compartments of the cell monolayer was analyzed by high performance liquid chromatography-mass spectrometry to calculate transfer rates and permeability coefficients.

RESULTS

Deoxynivalenol reduced the barrier integrity and caused cytotoxic effects at 10 μM concentrations. Slight alterations of the barrier integrity were also detected for 3-acetyldeoxynivalenol. The latter was transferred very quickly across the barrier and additionally cleaved to deoxynivalenol. The transfer of deoxynivalenol and moniliformin was slower, but clearly exceeded the permeability of the negative control. None of the compounds was enriched in one of the compartments, indicating that no efflux transport protein is involved in their transport.