Nontoxic concentrations of OTA aggravate DON-induced intestinal barrier dysfunction in IPEC-J2 cells via activation of NF-κB signaling pathway

Copper induces cytotoxicity in freshwater bivalve Anodonta woodiana hemocytes

Hemocytes of freshwater bivalves are an important target model for evaluating copper (Cu) toxicity in vitro, with excess Cu causing adverse responses in these organisms. Despite this, the mechanisms underlying cytotoxicity remain poorly understood. The freshwater bivalve Anodonta woodiana, employed as a model organism in freshwater environments, was utilized in this study. Hemocytes of A. woodiana were exposed to various aqueous Cu treatments (0.001, 0.01, 0.1, 1, and 10 mg/L), and a control group (no Cu added) for 3 h to investigate the cytotoxic mechanisms of Cu. The results showed a significant increase in the production of reactive oxygen species in hemocytes of all Cu exposed groups compared to the control (p < 0.05). Remarkably, Cu treatments disrupted the cellular membrane (p < 0.05) but did not induce significant changes in the stability of the lysosomal membrane. Cu targeted the mitochondria, leading to a reduction in mitochondrial membrane potential. Additionally, all Cu treatments significantly increased the degree of DNA damage (p < 0.05). Cellular damage and a significant decline in cell viability were observed when the Cu exposure concentration reached 0.1, 1, and 10 mg/L (p < 0.05). Our study provides new insights into the cytotoxicity mechanisms triggered by Cu in hemocytes of the freshwater bivalve A. woodiana, even under environmentally relevant conditions of 0.01 mg/L exposure.

Deoxynivalenol and T-2 toxin cause liver damage and egg quality degradation through endoplasmic reticulum stress in summer laying hens

The present study aimed to find whether low doses of mixed mycotoxins would affect egg quality in laying hens, and to explore the oxidative stress induced liver damage through endoplasmic reticulum during summer stress. A total of 96 Jinghong laying hens, 36 wks of age, were divided into four treatments, with eight repetitions per treatment and three hens per repetition. All the hens were raised in summer (average temperature: 31.3 ± 0.5℃; average humidity: 85.5 ± 0.2%) for 28d. One treatment was fed a basal diet as control (CON), and the other three treatments were fed the same diets containing 3.0 mg/kg deoxynivalenol (DON), 0.5 mg/kg T-2 toxin (T-2), and 1.5 mg/kg DON + 0.25 mg/kg T-2 toxin (Mix). Albumen height and Haugh unit were decreased (P < 0.05) in the Mix group on day 14 and 28. The activity of total antioxidant capacity, glutathione peroxidase, catalase, and superoxide dismutase were decreased (P < 0.05) in the DON, T-2, and Mix groups. The alkaline phosphatase level in DON, T-2, and Mix groups was significantly increased (P < 0.05). The level of interleukin-1β, interferon-γ, and tumor necrosis factor-α in the Mix group were higher (P < 0.05) than CON, DON, and T-2 groups. Mix group upregulated the mRNA expressions of protein kinase RNA-like ER kinase, activating transcription factor4, IL-1β, nuclear factor-κ-gene binding, and nuclear respiratory factor 2 in the liver (P < 0.05). The results showed that low doses of DON and T-2 toxin could cause oxidative stress in the liver, but DON and T-2 toxin have a cumulative effect on virulence, which can reduce egg quality and cause endoplasmic reticulum stress in the liver.

Toxicodynamic of combined mycotoxins: MicroRNAs and acute-phase proteins as diagnostic biomarkers

Mycotoxins, ubiquitous contaminants in food, present a global threat to human health and well-being. Mitigation efforts, such as the implementation of sound agricultural practices, thorough food processing, and the advancement of mycotoxin control technologies, have been instrumental in reducing mycotoxin exposure and associated toxicity. To comprehensively assess mycotoxins and their toxicodynamic implications, the deployment of effective and predictive strategies is imperative. Understanding the manner of action, transformation, and cumulative toxic effects of mycotoxins, moreover, their interactions with food matrices can be gleaned through gene expression and transcriptome analyses at cellular and molecular levels. MicroRNAs (miRNAs) govern the expression of target genes and enzymes that play pivotal roles in physiological, pathological, and toxicological responses, whereas acute phase proteins (APPs) exert regulatory control over the metabolism of therapeutic agents, both endogenously and posttranscriptionally. Consequently, this review aims to consolidate current knowledge concerning the regulatory role of miRNAs in the initiation of toxicological pathways by mycotoxins and explores the potential of APPs as biomarkers following mycotoxin exposure. The findings of this research highlight the potential utility of miRNAs and APPs as indicators for the detection and management of mycotoxins in food through biological processes. These markers offer promising avenues for enhancing the safety and quality of food products.

Ochratoxin A (OTA) causes intestinal aging damage through the NLRP3 signaling pathway mediated by calcium overload and oxidative stress

Ochratoxin A (OTA) is a widespread environmental toxin that poses a serious threat to human and animal health. OTA has been shown to cause cellular and tissue damage and is a global public health problem. However, the effects of OTA on gastrointestinal aging have not been reported. The aim of this study was to investigate the effects of OTA on intestinal aging in vitro and in vivo. In vitro experiments showed that OTA induced cellular inflammation through calcium overload and oxidative stress, significantly up-regulated the expression of P16, P21, and P53 proteins, markedly increased senescence-associated β-galactosidase activity (SA-β-gal) positive cells, and obviously decreased the expression of proliferating cell nuclear antigen (PCNA) proteins, which led to intestinal cell senescence. Meanwhile, we found that treatment with β-carotene ameliorated OTA-induced intestinal cell senescence. Consistent with the results of the in vitro experiments, in vivo studies showed that the intestinal aging of mice fed OTA was significantly higher than that of the control group. In conclusion, OTA may induce intestinal aging through calcium overload, oxidative stress and inflammation. This study lays a foundation for further research on the toxicological effects of OTA.

The coexistence of aflatoxin M1 and ochratoxin A induced intestinal barrier disruption via the regulation of key differentially expressed microRNAs and long non-coding RNAs in BALB/c mice

Food safety can be seriously threatened by the existence of both aflatoxin M1 (AFM1) and ochratoxin A (OTA) in milk and corresponding products. The importance of intestine integrity in preserving human health is widely understood in vitro, but the fundamental processes by which AFM1 and OTA cause disruption of the intestinal barrier are as yet unknown, especially in vivo. Based on the analysis of the whole transcriptome of BALB/c mice, the competing endogenous RNA (ceRNA) regulation network was obtained in the current study. Each of 12 mice were separated into five treatments: saline solution treatment, 1.0% DMSO vehicle control treatment, 3.0 mg/kg b.w. individual AFM1 treatment (AFM1), 3.0 mg/kg b.w. individual OTA treatment (OTA), and combined mycotoxins treatment (AFM1 +OTA). The study period lasted 28 days. The jejunum tissue was collected for the histological assessment and whole transcriptome analysis, and the whole blood was collected, and determination of serum biochemical indicators. The phenotypic results demonstrated that AFM1 and OTA caused intestinal barrier disruption via an increased apoptosis level and decreased expression of tight junction (TJ) proteins. The ceRNA network demonstrated that AFM1 and OTA induced cell apoptosis through activating the expression of DUSP9 and suppressing the expression of PLA2G2D, which were regulated by differentially expressed microRNAs (DEmiRNAs) (miR-124-y, miR-194-z, miR-224-x, and miR-452-x) and differentially expressed long non-coding RNAs (DElncRNAs) (FUT8 and GPR31C). And AFM1 and OTA decreased TJ proteins via inhibiting the expression of PAK6, which was regulated by several important DEmiRNAs and DElncRNAs. These DE RNAs in intestinal integrity were involved in MAPK and Ras signaling pathway. Overall, our findings expand the current knowledge regarding the potential mechanisms of intestinal integrity disruption brought on by AFM1 and OTA in vivo.

Deoxynivalenol: Emerging Toxic Mechanisms and Control Strategies, Current and Future Perspectives

Deoxynivalenol (DON) is the most frequently present mycotoxin contaminant in food and feed, causing a variety of toxic effects in humans and animals. Currently, a series of mechanisms involved in DON toxicity have been identified. In addition to the activation of oxidative stress and the MAPK signaling pathway, DON can activate hypoxia-inducible factor-1α, which further regulates reactive oxygen species production and cancer cell apoptosis. Noncoding RNA and signaling pathways including Wnt/β-catenin, FOXO, and TLR4/NF-κB also participate in DON toxicity. The intestinal microbiota and the brain-gut axis play a crucial role in DON-induced growth inhibition. In view of the synergistic toxic effect of DON and other mycotoxins, strategies to detect DON and control it biologically and the development of enzymes for the biodegradation of various mycotoxins and their introduction in the market are the current and future research hotspots.

iE-DAP Induced Inflammatory Response and Tight Junction Disruption in Bovine Mammary Epithelial Cells via NOD1-Dependent NF-κB and MLCK Signaling Pathway

γ-D-glutamyl-meso-diaminopimelic acid (iE-DAP), a bacterial cell wall component, can trigger an inflammatory response. A mammary inflammatory response causes tight junction (TJ) dysfunction. This study aimed to explore the effects and involved mechanisms of iE-DAP-induced inflammatory response on the TJ integrity in bovine mammary epithelial cells (BMECs). The results showed that iE-DAP-induced inflammatory response and TJ disruption was associated with increased expression levels of inflammatory cytokines and decreased gene expression of ZO-1 and Occludin, as well as a reduction in transepithelial electrical resistance and elevation in paracellular dextran passage. While MLCK inhibitor ML-7 reversed the TJ disruption induced by iE-DAP. NF-κB inhibitor BAY 11-7085 hindered the activation of NF-κB and MLCK signaling pathways, the inflammatory response and TJ disruption induced by iE-DAP. NOD1-specific shRNA also inhibited the activation of the NOD1/NF-κB signaling pathway and reversed the inflammatory response and TJ injury in iE-DAP-treated BMECs. Above results suggest that iE-DAP activated the NF-κB and MLCK signaling pathway in NOD1-dependent manner, which promoted the transcription of inflammatory cytokines and altered the expression and distribution of tight junction proteins, finally caused inflammatory response and TJ disruption. This study might provide theoretical basis and scientific support for the prevention and treatment of mastitis.

Absorption and Transport Mechanism of Red Meat-Derived N-glycolylneuraminic Acid and Its Damage to Intestinal Barrier Function through the NF-κB Signaling Pathway

N-glycolylneuraminic acid (Neu5Gc) is a specific factor in red meat that induces intestinal disease. Our aim was to investigate the effect of Neu5Gc on the intestinal barrier as well as its mechanism of endocytosis and exocytosis. Ten specific inhibitors were used to explore the mechanism of Neu5Gc endocytosis and exocytosis by Caco-2 cells. Amiloride hydrochloride and cytochalasin D had the strongest inhibitory effect on the endocytosis of Neu5Gc. Sodium azide, dynasore, chlorpromazine hydrochloride, and nystatin also inhibited Neu5Gc endocytosis. Dynasore exhibited a stronger inhibitory effect than that of chlorpromazine hydrochloride or nystatin alone. Exocytosis inhibitors, including nocodazole, brefeldin A, monensin, and bafilomycin A, inhibited the transmembrane transport of Neu5Gc. Monensin promoted the exocytosis of Neu5Gc from Caco-2 cells. In another experiment, we observed no significant inhibitory effects of monensin and brefeldin A. Dietary concentrations of Neu5Gc induced prominent damage to intestinal tight junction proteins zonula occludens-1 (ZO-1), occludin, and claudin-1 and promoted the phosphorylation of IκB-α and P65 to activate the canonical Nuclear Factor kappa-B (NF-κB) pathway. Neu5Gc increased the RNA levels of pro-inflammatory factors IL-1β, IL-6, and TNF-α and inhibited those of anti-inflammatory factors TGF-β and IL-10. BAY, an NF-κB signaling pathway inhibitor, attenuated these changes. Reductions in the levels of ZO-1, occludin, and claudin-1 were recovered in response to BAY. Our data reveal the endocytosis and exocytosis mechanism of Neu5Gc and prove that Neu5Gc can activate the canonical NF-κB signaling pathway, regulate the transcription of inflammatory factors, thereby damaging intestinal barrier function.

Nontoxic Concentration of Ochratoxin A Aggravates Renal Fibrosis Induced by Adriamycin/Cyclosporine A Nephropathy via TGF-β1/SMAD2/3

Ochratoxin A (OTA) is the most common contaminant in food and feed, which causes nephrotoxicity. Studies revealed that a low level of OTA contamination could also cause physiological dysfunction. Chronic kidney disease (CKD) has become an important public health problem with increasing morbidity. However, the potential effect of nontoxic OTA on CKD remains uncertain. In this study, adriamycin (ADR) and cyclosporine A (CSA) were used to stimulate glomerular nephropathy and tubular nephropathy, respectively. Renal injury was aggravated due to OTA (0.25 mg/kg) exposure in the mouse nephropathy models, assessing by renal histomorphology and the detection of blood urea nitrogen (BUN) and serum creatine (SCr) levels. We noticed that nontoxic dosage of OTA increased the expression of fibrotic factors, α-smooth muscle actin (α-SMA), and Vimentin in a nephropathic mouse, which indicated the exacerbation of ADR/CSA-induced renal fibrosis. We conducted in vitro experiments in glomerular mesangial cells and renal tubular epithelial cells. Nontoxic concentration of OTA was found to exacerbate the cytotoxicity of ADR/CSA and intensify renal fibrosis by activating TGF-β1/SMAD2/3. Thus, this study may provide convincing evidence for the prevention of CKD aggravation and the renewal of food hygiene standards in mycotoxin contamination.

Analysis of the roles of the Notch1 signalling pathway in modulating deoxynivalenol cytotoxicity

Deoxynivalenol (DON) is a trichothecenes produced by fungi that is widespread and poses a threat to human and animal health. The Notch1 signalling pathway is tightly involved in cell fate determination. The aim of this study was to investigate the role of the Notch1 signalling pathway in DON exposure. Herein, we found that the Notch1 signalling pathway was significantly activated after DON exposure, while Notch1 expression was negatively regulated by DON-induced ROS. Then, the Notch1 signalling pathway was blocked by the γ-secretase inhibitor DAPT in DON exposure. Flow cytometry analysis and antioxidant parameter measurements revealed that DAPT treatment significantly aggravated the oxidative stress induced by DON. The detection of apoptosis showed that DAPT treatment increased the cell apoptotic rate. Further analysis revealed that inhibiting the Notch1 signalling pathway reduced autophagy upon DON exposure. RT-qPCR and Western blot analysis showed that inhibiting the Notch1 signalling pathway aggravated cellular inflammation and activated the MAPK pathway, indicating that the MAPK pathway may be the downstream signalling pathway. Taken together, our research revealed that the Notch1 signalling pathway is essential for protection against DON. Inhibition of Notch1 signalling increases oxidative stress, causes cell apoptosis, reduces autophagy and aggravates cell inflammation after DON exposure. This study investigated the role of the Notch1 signalling pathway in DON exposure and provided a basis for exploring the mechanism of DON.

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.

Gene expression profiling after ochratoxin A treatment in small intestinal epithelial cells from pigs

Ochratoxin A (OTA) is a well-known mycotoxin that causes disease through the ingestion of contaminated food or feed, for example, in the porcine industry. The intestinal epithelium acts as the first barrier against food contamination. We conducted a study on the exposure of the porcine intestinal epithelium to OTA. We used the intestinal porcine epithelial cell line IPEC-J2 as an in vitro model to evaluate the altered molecular mechanisms following OTA exposure. Gene expression profiling revealed that OTA upregulated 782 genes and downregulated 896, totalling 1678 differentially expressed genes. Furthermore, immunofluorescence, quantitative real-time polymerase chain reaction, and western blotting confirmed that OTA damages the tight junction protein ZO-1. Moreover, OTA activated the expression of inflammatory genes (IL-6, IL-8, IL-10, NF-kB, TLR4, and TNF-α). In summary, this study confirmed that OTA alters various molecular mechanisms and has several adverse effects on IPEC-J2 cells.

Protective and detoxifying effects conferred by selenium against mycotoxins and livestock viruses: A review

Animal feed can easily be infected with molds during production and storage processes, and this can lead to the production of secondary metabolites, such as mycotoxins, which eventually threaten human and animal health. Furthermore, livestock production is also not free from viral infections. Under these conditions, the essential trace element, selenium (Se), can confer various biological benefits to humans and animals, especially due to its anticancer, antiviral, and antioxidant properties, as well as its ability to regulate immune responses. This article reviews the latest literature on the antagonistic effects of Se on mycotoxin toxicity and viral infections in animals. We outlined the systemic toxicity of mycotoxins and the primary mechanisms of mycotoxin-induced toxicity in this analysis. In addition, we pay close attention to how mycotoxins and viral infections in livestock interact. The use of Se supplementation against mycotoxin-induced toxicity and cattle viral infection was the topic of our final discussion. The coronavirus disease 2019 (COVID-19) pandemic, which is currently causing a health catastrophe, has altered our perspective on health concerns to one that is more holistic and increasingly embraces the One Health Concept, which acknowledges the interdependence of humans, animals, and the environment. In light of this, we have made an effort to present a thorough and wide-ranging background on the protective functions of selenium in successfully reducing mycotoxin toxicity and livestock viral infection. It concluded that mycotoxins could be systemically harmful and pose a severe risk to human and animal health. On the contrary, animal mycotoxins and viral illnesses have a close connection. Last but not least, these findings show that the interaction between Se status and host response to mycotoxins and cattle virus infection is crucial.

Effects of deoxynivalenol on the histomorphology of the liver and kidneys and the expression of MAPKs in weaned rabbits

Deoxynivalenol (DON) is widely present in grain-based feeds and food. It has attracted great attention due to its high contamination rate and strong toxicity. The objective of this study was to analyse the toxic effects of DON on the liver and kidneys of weaned rabbits. 45 weaned male rabbits were allocated into control, low DON dose (0.5 mg/kg body weight), and high DON dose (1.5 mg/kg body weight) groups. Saline or DON was administrated intragastrically in the empty stomach of rabbits every morning. After 24 days of treatment, liver and kidney samples were collected for histological, reverse transcription-quantitative polymerase chain reaction (qRT-PCR), and immunohistochemistry analyses. Haematoxylin eosin staining showed that 0.5 mg/kg BW DON caused mild damage to the liver and kidney morphology, while 1.5 mg/kg body weight DON resulted in hepatic vacuolation and necrosis, as well as tubular stenosis and lesions. Data from qRT-PCR, Western blot, and immunohistochemistry revealed that the mRNA and protein expression and the distribution range of extracellular signal-regulated kinase, p38, and c-Jun NH2-terminal kinase were increased in the liver and kidneys. In conclusion, DON at the tested concentrations damaged the liver and kidneys of rabbits by affecting the expression of key proteins from the mitogen-activated protein kinase signalling pathway. The damage extent was proportional to the amount of DON ingested.

Phenethyl isothiocyanate as an anti-nutritional factor attenuates deoxynivalenol-induced IPEC-J2 cell injury through inhibiting ROS-mediated autophagy

Deoxynivalenol (DON) is considered to be the most harmful mycotoxin that affects the intestinal health of animals and humans. Phenethyl isothiocyanate (PEITC) in feedstuff is an anti-nutritional factor and impairs nutrient digestion and absorption in the animal intestinal. In the current study, we aimed to explore the effects of PEITC on DON-induced apoptosis, intestinal tight junction disorder, and its potential molecular mechanism in the porcine jejunum epithelial cell line (IPEC-J2). Our results indicated that PEITC treatment markedly alleviated DON-induced cytotoxicity, decreasing the apoptotic cell percentage and pro-apoptotic mRNA/protein levels, and increasing zonula occludens-1 (ZO-1), occludin and claudin-1 mRNA/protein expression. Meanwhile, PEITC treatment ameliorated DON-induced an increase of the inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2) mRNA levels and intracellular reactive oxygen species (ROS) level, and a decrease of glutathione peroxidase 1 (GPx1), superoxide dismutase 2 (SOD2), catalase (CAT) and heme oxygenase 1 (HO-1) mRNA levels. Additionally, PEITC treatment significantly down-regulated autophagy-related protein 5 (ATG5), beclin-1 and microtubule-associated protein 1 light chain 3B (LC3-Ⅱ) mRNA/protein levels, decreased the number of green fluorescent protein-microtubule-associated protein 1 light-chain 3 (GFP-LC3) puncta and phosphatidylinositol 3 kinase (PI3K) protein expression, and up-regulated phospho-protein kinase B (p-Akt) and phospho-mammalian target of rapamycin (p-mTOR) protein expression against DON. However, the activation of autophagy by rapamycin, an autophagy agonist, abolished the protective effects of PEITC against DON-induced cytotoxicity, apoptosis and intestinal tight junction disorder. Collectively, PEITC could confer protection against DON-induced porcine intestinal epithelial cell injury by suppressing ROS-mediated autophagy.

Ex Vivo and In Vitro Studies Revealed Underlying Mechanisms of Immature Intestinal Inflammatory Responses Caused by Aflatoxin M1 Together with Ochratoxin A

Aflatoxin M1 (AFM1) and ochratoxin A (OTA), which are occasionally detected in milk and commercial baby foods, could easily enter and reach the gastrointestinal tract, posing impairment to the first line of defense and causing dysfunction of the tissue. The objective of this study was to investigate the immunostimulatory roles of individual and combined AFM1 and OTA on the immature intestine. Thus, we used ELISA assays to evaluate the generation of cytokines from ex vivo CD-1 fetal mouse jejunum induced by AFM1 and OTA and explored the related regulatory pathways and pivot genes using RNA-seq analysis. It was found that OTA exhibited much stronger ability in stimulating pro-inflammatory cytokine IL-6 from jejunum tissues than AFM1 (OTA of 4 μM versus AFM1 of 50 μM), whereas the combination of the two toxins seemed to exert antagonistic actions. In addition, transcriptomics also showed that most gene members in the enriched pathway ‘cytokine–cytokine receptor interaction’ were more highly expressed in OTA than the AFM1 group. By means of PPI network analysis, NFKB1 and RelB were regarded as hub genes in response to OTA but not AFM1. In the human FHs 74 Int cell line, both AFM1 and OTA enhanced the content of reactive oxygen species, and the oxidative response was more apparent in OTA-treated cells in comparison with AFM1. Furthermore, OTA and AFM1 + OTA raised the protein abundance of p50/RelB, and triggered the translocation of the dimer from cytosol to nucleus. Therefore, the experimental data ex vivo and in vitro showed that OTA-induced inflammation was thought to be bound up with the up-regulation and translocation of NF-κB, though AFM1 seemed to have no obvious impact. Since it was the first attempt to uncover the appearances and inner mechanisms regarding inflammation provoked by AFM1 and OTA on immature intestinal models, further efforts are needed to understand the detailed metabolic steps of the toxin in cells and to clarify their causal relationship with the signals proposed from current research.

In vitro and in vivo evaluation of AFB1 and OTA-toxicity through immunofluorescence and flow cytometry techniques: A systematic review

Due to the globalization, mycotoxins have been considered a major risk to human health being the main contaminants of foodstuffs. Among them, AFB1 and OTA are the most toxic and studied. Therefore, the goal of this review is to deepen the knowledge about the toxicological effects that AFB1 and OTA can induce on human health by using flow cytometry and immunofluorescence techniques in vitro and in vivo models. The examination of the selected reports shows that the majority of them are focused on immunotoxicity while the rest are concerned about nephrotoxicity, hepatotoxicity, gastrointestinal toxicity, neurotoxicity, embryotoxicity, reproductive system, breast, esophageal and lung toxicity. In relation to immunofluorescence analysis, biological processes related to AFB1- and OTA-toxicity were evaluated such as inflammation, neuronal differentiation, DNA damage, oxidative stress and cell death. In flow cytometry analysis, a wide range of assays have been performed across the reviewed studies being apoptosis assay, cell cycle analysis and intracellular ROS measurement the most employed. Although, the toxic effects of AFB1 and OTA have been reported, further research is needed to clarify AFB1 and OTA-mechanism of action on human health.

Lycopene Protects Intestinal Epithelium from Deoxynivalenol-Induced Oxidative Damage via Regulating Keap1/Nrf2 Signaling

Deoxynivalenol (DON) is a threatening mycotoxin primarily present in the agricultural environment, especially in food commodities and animal forages, and exerts significant global health hazards. Lycopene (LYC) is a potent antioxidant carotenoid mainly present in tomatoes and other fruits with enormous health benefits. The present study was designed to ascertain whether LYC could protect DON-induced intestinal epithelium oxidative injury by regulating Keap1/Nrf2 signaling in the intestine of mice. A total of forty-eight mice were randomly distributed into four groups (n = 12), Control (CON), 10 mg/kg BW LYC, 3 mg/kg BW DON, and 3 mg/kg DON + 10 mg/kg LYC BW (DON + LYC). The experimental groups were treated by intragastric administration for 11 days. Our results showed that LYC significantly increased average daily feed intake (ADFI), average daily gain (ADG), and repaired intestinal injury and barrier dysfunction, as evident by increased trans-epithelial electrical resistance (TEER) and decreased diamine oxidase (DAO) activity, as well as up-regulated tight junction proteins (occludin, claudin-1) under DON exposure. Furthermore, LYC treatment stabilized the functions of intestinal epithelial cells (Lgr5, PCNA, MUC2, LYZ, and Villin) under DON exposure. Additionally, LYC alleviated DON-induced oxidative stress by reducing ROS and MDA accumulation and enhancing the activity of antioxidant enzymes (CAT, T-SOD, T-AOC, and GSH-Px), which was linked with the activation of Nrf2 signaling and degradation of Keap1 expression. Conclusively, our findings demonstrated that LYC protects intestinal epithelium from oxidative injury by modulating the Keap1/Nrf2 signaling pathway under DON exposure. These novel findings could lead to future research into the therapeutic use of LYC to protect the DON-induced harmful effects in humans and/or animals.

Whole transcriptome-based ceRNA network analysis revealed ochratoxin A-induced compromised intestinal tight junction proteins through WNT/Ca2+ signaling pathway

Ochratoxin A (OTA) is a widespread environmental pollutant that is a threat to humans and livestock and remains a global concern to public health. It has negative effects on both humans and animals that are in a continuously exposed environment. The compromised intestinal barrier caused by OTA has aroused widespread concern. This study aimed to investigate the mechanism of OTA-induced tight junction (TJ) protein damage and the relevant components of the intestinal barrier through in vivo whole transcriptome analysis combined with in vitro functional verification. Bioinformatics analysis in OTA-treated Balb/c mice demonstrated that regulated TJ protein related mRNAs were perturbed, and activated the WNT/Ca2+ signaling pathway possibly regulated by key lncRNAs and miRNAs. Competing endogenous RNA (ceRNA) network analysis revealed that lncRNA Zeb1 regulated FZD4 binding with WNT5a to release Ca2+ by targeting miR-1258-x and reduced the expression of TJ proteins, thus damaging the function of the intestinal barrier. An in vitro experiment with Caco-2 cells verified that an increase in Ca2+ level was involved in OTA-induced decreases in the expression of TJ proteins. Taken together, these results will help to identify targets in the intestinal barrier that are compromised by OTA, and will provide the basis for preventing the associated hazard and risk.

Comparative sensitivity of proliferative and differentiated intestinal epithelial cells to the food contaminant, deoxynivalenol

The intestinal epithelium is a functional and physical barrier formed by a cell monolayer that constantly differentiates from a stem cell in the crypt. This is the first target for food contaminants, especially mycotoxins. Deoxynivalenol (DON) is one of the most prevalent mycotoxins. This study compared the effects of DON (0-100 μM) on proliferative and differentiated intestinal epithelial cells. Three cell viability assays (LDH release, ATP content and neutral red uptake) indicated that proliferative Caco-2 cells are more sensitive to DON than differentiated ones. The establishment of transepithelial electrical resistance (TEER), as a read out of the differentiation process, was delayed in proliferative cells after exposure to 1 μM DON. Transcriptome analysis of proliferative and differentiated exposure to 0-3 μM DON for 24 h revealed 4862 differentially expressed genes (DEG) and indicated an effect of both the differentiation status and the DON treatment. KEGG enrichment analysis indicated involvement of metabolism, ECM receptors and tight junctions in the differentiation process, while ribosome biogenesis, mRNA surveillance, and the MAPK pathway were involved in the response to DON. The number of differentially expressed genes and the amplitude of the effect were higher in proliferative cells exposed to DON than that in differentiated cells. In conclusion, our study shows that proliferative cells are more susceptible than differentiated ones to DON and that the mycotoxin delays the differentiation process.

Nontoxic dose of Phenethyl isothiocyanate ameliorates deoxynivalenol-induced cytotoxicity and inflammation in IPEC-J2 cells

The intestinal tract is a target for the deoxynivalenol (DON), which has adverse effects in animals and humans' health by affecting intestinal functions. Phenethyl isothiocyanate (PEITC) is an important degradation product of glucosinolates (GSLs), belonging to an anti-nutritional factor that affects the digestion and absorption of nutrients in the animals' intestinal. However, little attention has been paid to the interaction and its mechanism between DON and PEITC. Therefore, the purpose of this study was to assess the effects of PEITC on DON-induced cytotoxicity and inflammation, and explore the potential mechanisms in IPEC-J2 cells. Our results showed that DON exposure could decrease the cell viability and pro-inflammatory cytokine expression in IPEC-J2 cells in a dose-dependent manner. PEITC treatment at the concentrations of 1.25-5 μM had no significant effect on IPEC-J2 cells viability, but above 10 μM of PEITC treatment significantly reduced the cell viability. Interestingly, 1.25-5 μM of PEITC treatment could suppress 4 μM of DON-induced decrease in cell viability and increase in pro-inflammatory cytokine expression. Meanwhile, the protein ratios of p-p65/p-65 and p-IκBα/IκBα were markedly decreased in the groups treated with 1.25-5 μM PEITC compared to DON exposure alone. However, the protective effects of PEITC treatment were significantly blocked after pre-treatment with LPS, NF-κB activator, in IPEC-J2 cells. In conclusion, these findings indicated that the nontoxic dose of PEITC could alleviate DON-induced cytotoxicity and inflammation responses via suppressing the NF-κB signaling pathway in IPEC-J2 cells. Our results provide a new theoretical basis for the rational addition of rapeseed meal in animal feedstuff.

Astaxanthin Alleviates Ochratoxin A-Induced Cecum Injury and Inflammation in Mice by Regulating the Diversity of Cecal Microbiota and TLR4/MyD88/NF-κB Signaling Pathway

Ochratoxin A (OTA) is a common environmental pollutant found in a variety of foods and grains, and excessive OTA consumption causes serious global health effects on animals and humans. Astaxanthin (AST) is a natural carotenoid that has anti-inflammatory, antiapoptotic, immunomodulatory, antitumor, antidiabetes, and other biological activities. The present study is aimed at investigating the effects of AST on OTA-induced cecum injury and its mechanism of action. Eighty C57 mice were randomly divided into four groups, including the control group, OTA group (5 mg/kg body weight), AST group (100 mg/kg body weight), and AST intervention group (100 mg/kg body weight AST+5 mg/kg body weight OTA). It was found that AST decreased the endotoxin content, effectively prevented the shortening of mouse cecum villi, and increased the expression levels of tight junction (TJ) proteins, consisting of occludin, claudin-1, and zonula occludens-1 (ZO-1). AST increased the number of goblet cells, the contents of mucin-2 (MUC2), and defensins (Defa5 and β-pD2) significantly, while the expression of mucin-1 (MUC1) decreased significantly. The 16S rRNA sequencing showed that AST affected the richness and diversity of cecum flora, decreased the proportion of lactobacillus, and also decreased the contents of short-chain fatty acids (SCFAs) (acetate and butyrate). In addition, AST significantly decreased the expression of TLR4, MyD88, and p-p65, while increasing the expression of p65. Meanwhile, the expression of inflammatory factors including TNF-α and INF-γ decreased, while the expression of IL-10 increased. In conclusion, AST reduced OTA-induced cecum injury by regulating the cecum barrier function and TLR4/MyD88/NF-κB signaling pathway.

Maternally expressed 3 protects the intestinal barrier from cardiac arrest-induced ischemia/reperfusion injury via miR-34a-3p/sirtuin 1/nuclear factor kappa B signaling

BACKGROUND

Cardiac arrest (CA), a common disease with a high mortality rate, is a leading cause of ischemia/reperfusion (I/R)-induced dysfunction of the intestinal barrier. Long non-coding RNAs (lncRNAs) play crucial roles in multiple pathological processes. However, the effect of the lncRNA maternally expressed 3 (MEG3) on intestinal I/R injury and the intestinal barrier has not been fully determined. Therefore, this study aimed to investigate the function of MEG3 in CA-induced intestinal barrier dysfunction.

METHODS

The oxygen and glucose deprivation (OGD) model in the human colorectal adenocarcinoma Caco-2 cells and in vivo cardiac arrest-induced intestinal barrier dysfunction model in Sprague-Dawley (SD) rats were established. The effect and underlying mechanism of MEG3 on the intestinal barrier from cardiac arrest-induced ischemia/reperfusion injury were analyzed by methyl thiazolyl tetrazolium (MTT) assays, Annexin V-FITC/PI apoptosis detection kit, Terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL) staining, quantitative polymerase chain reaction (qPCR) assays, Western blot analysis, luciferase reporter gene assays, transepithelial electrical resistance (TEER) measurements, immunofluorescence analysis, and enzyme-linked immunosorbent assay (ELISA) assays.

RESULTS

Interestingly, we found that MEG3 could protect Caco-2 cells from oxygen-glucose deprivation (OGD)/reoxygenation-induced I/R injury by modulating cell proliferation and apoptosis. Moreover, MEG3 relieved OGD-induced intestinal barrier dysfunction in vitro, as demonstrated by its significant rescue effect on transepithelial electrical resistance and the expression of tight junction proteins such as occludin and claudin-1 (CLDN1), which were impaired in OGD-treated Caco-2 cells. Mechanistically, MEG3 inhibited the expression of inflammatory factors including interleukin (IL)-1β, tumor necrosis factor (TNF)-α, interferon-gamma (IFN)-γ, inflammatory factors including interleukin (IL)-10, and transforming growth factor beta (TGFb)-1, as well as nuclear factor-kappa B (NF-κB) signaling. In response to OGD treatment in vitro, MEG3 also activated the expression of sirtuin 1 (SIRT1) by Caco-2 cells via sponging miR-34a-3p. Furthermore, MEG3 relieved CA-induced intestinal barrier dysfunction through NF-κB signaling in vivo.

CONCLUSIONS

LncRNA MEG3 can protect the intestinal barrier from cardiac arrest-induced I/R injury via miR-34a-3p/SIRT1/NF-κB signaling. This finding provides new insight into the mechanism by which MEG3 restores intestinal barrier function following I/R injury, presenting it as a potential therapeutic candidate or strategy in intestinal injury.

The Compromised Intestinal Barrier Induced by Mycotoxins

Mycotoxins are fungal metabolites that occur in human foods and animal feeds, potentially threatening human and animal health. The intestine is considered as the first barrier against these external contaminants, and it consists of interconnected physical, chemical, immunological, and microbial barriers. In this context, based on in vitro, ex vivo, and in vivo models, we summarize the literature for compromised intestinal barrier issues caused by various mycotoxins, and we reviewed events related to disrupted intestinal integrity (physical barrier), thinned mucus layer (chemical barrier), imbalanced inflammatory factors (immunological barrier), and dysfunctional bacterial homeostasis (microbial barrier). We also provide important information on deoxynivalenol, a leading mycotoxin implicated in intestinal dysfunction, and other adverse intestinal effects induced by other mycotoxins, including aflatoxins and ochratoxin A. In addition, intestinal perturbations caused by mycotoxins may also contribute to the development of mycotoxicosis, including human chronic intestinal inflammatory diseases. Therefore, we provide a clear understanding of compromised intestinal barrier induced by mycotoxins, with a view to potentially develop innovative strategies to prevent and treat mycotoxicosis. In addition, because of increased combinatorial interactions between mycotoxins, we explore the interactive effects of multiple mycotoxins in this review.

Deoxynivalenol induced spermatogenesis disorder by blood-testis barrier disruption associated with testosterone deficiency and inflammation in mice

Deoxynivalenol (DON) is an unavoidable cereal crops contaminants and environmental pollutants, which seriously threated the health of human and animal. DON has been reported to exert significant toxicity effects on spermatogenesis, but the underlying mechanisms remain largely inconclusive. The blood-testis barrier (BTB) provides a specialized biochemical microenvironment for maintaining spermatogenesis. Thus, we hypothesized that DON could impair BTB and lead to spermatogenesis disorder. To confirm this hypothesis, sixty male mice were intragastrically administered with 0, 1.2, 2.4 and 4.8 mg/kg body weight DON for 28 days, and several important observations were obtained in present study. First, we found that DON induced spermatogenesis disorder, reflected by the declines of sperm concentration and quality, sperm ultrastructural damage as well as seminiferous tubular damage. Then, we proved that DON induced BTB disruption as well as decreased the expressions of BTB junction proteins, including Occludin, Connexin 43 and N-cadherin. Finally, the present study showed that DON induced inflammation and inhibited T biosynthesis in testis of mice. These results revealed that DON induced spermatogenesis disorder by BTB disruption associated with testosterone deficiency and inflammation in mice, which shed a new light on the potential mechanisms of reproductive toxicity induced by DON.

Nontoxic-dose deoxynivalenol aggravates lipopolysaccharides-induced inflammation and tight junction disorder in IPEC-J2 cells through activation of NF-κB and LC3B

Lipopolysaccharide (LPS) is the key factor in various intestinal inflammation which could disrupt the epithelial barrier function. Deoxynivalenol (DON), a well-known mycotoxin, can induce intestinal injury. However, the combined enterotoxicity of LPS and DON has rarely been studied. In this study, IPEC-J2 cell monolayers were exposed to LPS and nontoxic-dose DON for 12 and 24 h to investigate the effects of DON on LPS-induced inflammatory response and tight junction variation, and specific inhibitor and CRISPR-Cas9 were used to explore the underlying mechanisms. Our results showed that nontoxic-dose DON aggravated LPS-induced cellular inflammatory response, reflecting on more significant changes of inflammatory cytokines mRNA expression, higher protein expression of NOD-like receptor protein 3 (NLRP3) and procaspase-1. Moreover, nontoxic-dose DON aggravated LPS-induced mRNA and protein expression decreased, and distribution confused of tight junction proteins. We found that DON further enhanced LPS-induced phosphorylation and nucleus translocation of p65, and expression of LC3B-Ⅱ. NF-κB inhibitor and CRISPR-Cas9-mediated knockout of LC3B attenuated the effects of combination which indicated nontoxic-dose DON aggravated LPS-induced intestinal inflammation and tight junction disorder through activating NF-κB signaling pathway and autophagy-related protein LC3B. It further warns that ingesting low doses of mycotoxins may exacerbate the effects of intestinal pathogens on the body.

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Nontoxic-dose DON aggravates LPS-induced cellular inflammatory response in IPEC-J2 cell monolayers.

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Nontoxic-dose DON aggravates LPS-induced decrease and distribution disorder of tight junction in IPEC-J2 cell monolayers.

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Nontoxic-dose DON aggravates LPS-induced inflammatory response and tight junction disorder by activating NF-κB and LC3B.

Deoxynivalenol Induces Inflammation in IPEC-J2 Cells by Activating P38 Mapk And Erk1/2

Fusarium-derived mycotoxin deoxynivalenol (DON) usually induces diarrhea, vomiting and gastrointestinal inflammation. We studied the cytotoxic effect of DON on porcine small intestinal epithelium using the intestinal porcine epithelial cell line IPEC-J2. We screened out differentially expressed genes (DEGs) using RNA-seq and identified 320 upregulated genes and 160 downregulated genes. The enrichment pathways of these DEGs focused on immune-related pathways. DON induced proinflammatory gene expression, including cytokines, chemokines and other inflammation-related genes. DON increased IL1A, IL6 and TNF-α release and DON activated the phosphorylation of extracellular signal-regulated kinase-1 and-2 (ERK1/2), JUN N-terminal kinase (JNK) and p38 MAPK. A p38 inhibitor attenuated DON-induced IL6, TNF-α, CXCL2, CXCL8, IL12A, IL1A, CCL20, CCL4 and IL15 production, while an ERK1/2 inhibitor had only a small inhibitory effect on IL15 and IL6. An inhibitor of p38 MAPK decreased the release of IL1A, IL6 and TNF-α and an inhibitor of ERK1/2 partly attenuated protein levels of IL6. These data demonstrate that DON induces proinflammatory factor production in IPEC-J2 cells by activating p38 and ERK1/2.

Mycotoxin Altertoxin II Induces Lipid Peroxidation Connecting Mitochondrial Stress Response to NF-κB Inhibition in THP-1 Macrophages

Prolonged exposure to mycotoxins, even in subtoxic concentrations, might contribute to modulate pro- or anti-inflammatory cascades and ultimately have long-term consequences on our health. In line, there is an increasing need to describe and comprehend the potential immunomodulatory effects of toxins that can be produced from fungi proliferating even in a domestic environment like, for instance, Alternaria alternata. Taking this as a starting point, we investigated the effects of one of the most potent genotoxic compounds produced by this fungi type, namely altertoxin II (ATXII) on THP-1 macrophages. In noncytotoxic concentrations (0.1-1 μM), ATXII inhibited the activation of the transcription factor NF-κB, and this event was accompanied by significant mitochondrial superoxide production (1 μM ATXII). Both responses seemed dependent on membrane structure and morphology since they were modulated by the coincubation with the cholesterol complexing agent methyl-β-cyclodextrin (MβCD, 10-50 μM). Moreover, toxicity of ATXII was enhanced by cholesterol load (cholesterol-MβCD). The mycotoxin induced also lipid peroxidation (1-10 μM, ATXII) possibly streaming down at the mitochondrial level and suppressing NF-κB activation in THP-1 macrophages.

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.