In vitro and in vivo effects of a mycotoxin, deoxynivalenol, and a trace metal, cadmium, alone or in a mixture on the intestinal barrier

Necroptosis contributes to the intestinal toxicity of deoxynivalenol and is mediated by methyltransferase SETDB1

Deoxynivalenol (DON) is a secondary metabolite produced by fungi, which causes serious health issues worldwide due to its widespread presence in human and animal diets. Necroptosis is a newly proposed cell death mode and has been proposed as a potential mechanism of intestinal disease. This study aimed to investigate the role of necroptosis in intestinal damage caused by DON exposure. Piglets were fed diets with or without 4 mg/kg DON for 3 weeks or given a gavage of 2 mg/kg BW DON or sterile saline to investigate the effects of chronic or acute DON exposure on the gut, respectively. IPEC-1 cells were challenged with different concentrations of DON to investigate the effect of DON exposure on the intestinal epithelial cells (IECs) in vitro. Subsequently, the inhibitors of necroptosis were used to treat cells or piglets prior to DON challenge. Chronic and acute DON exposure both caused morphological damage, reduction of disaccharidase activity, decrease of tight junction protein expression, inflammation of the small intestine, and necroptosis of intestinal epithelial cells in piglets. Necroptosis was also detected when IPEC-1 cell damage was induced by DON in vitro. The suppression of necroptosis in IPEC-1 cells by inhibitors (necrostatin-1 (Nec-1), GSK'872, or GW806742X) alleviated cell death, the decrease of tight junction protein expression, oxidative stress, and the inflammatory response induced by DON. Furthermore, pre-treatment with Nec-1 in piglets was also observed to protect the intestine against DON-induced enterotoxicity. Additionally, the expression of histone methyltransferase SETDB1 was abnormally downregulated upon chronic and acute DON exposure in piglets, and necroptosis was activated in IPEC-1 cells due to knockout of SETDB1. Collectively, these results demonstrate that necroptosis of IECs is a mechanism of DON-induced enterotoxicity and SETDB1 mediates necroptosis upon DON exposure in IECs, suggesting the potential for targeted inhibition of necroptosis to alleviate mycotoxin-induced enterotoxicity and intestinal disease.

Epigallocatechin-3-gallate mitigates cadmium-induced intestinal damage through modulation of the microbiota-tryptophan-aryl hydrocarbon receptor pathway

Early studies have shown that the gut microbiota is a critical target during cadmium exposure. The prebiotic activity of epigallocatechin-3-gallate (EGCG) plays an essential role in treating intestinal inflammation and damage. However, the exact intestinal barrier protection mechanism of EGCG against cadmium exposure remains unclear. In this experiment, four-week-old mice were exposed to cadmium (5 mg kg-1) for four weeks. Through 16 S rDNA analysis, we found that cadmium disrupted the gut microbiota and inhibited the indole metabolism pathway of tryptophan (TRP), which serves as the principal microbial production route for endogenous ligands to activate the aryl hydrocarbon receptor (AhR). Additionally, cadmium downregulated the intestinal AhR signaling pathway and harmed the intestinal barrier function. Treatment with EGCG (20 mg kg-1) and the AhR agonist 6-Formylindolo[3,2-b] carbazole (FICZ) (1 μg/d) significantly activated the AhR pathway and alleviated intestinal barrier injury. Notably, EGCG partially restored the gut microbiota and upregulated the TRP-indole metabolism pathway to increase the level of indole-related AhR agonists. Our findings demonstrate that cadmium dysregulates common gut microbiota to disrupt TRP metabolism, impairing the AhR signaling pathway and intestinal barrier. EGCG reduces cadmium-induced intestinal functional impairment by intervening in the intestinal microbiota to metabolize AhR agonists. This study offers insights into the toxic mechanisms of environmental cadmium and a potential mechanism to protect the intestinal barrier with EGCG.

Tributyltin (TBT) toxicity: Effects on enteric neuronal plasticity and intestinal barrier of rats' duodenum

Tributyltin (TBT) is a biocide used in the formulation of antifouling paints and it is highly harmful. Despite the ban, the compound persists in the environment, contaminating marine foodstuffs and household products. Therefore, considering the route of exposure to the contaminant, the gastrointestinal tract (GIT) acts as an important barrier against harmful substances and is a potential biomarker for understanding the consequences of these agents. This work aimed to evaluate histological and neuronal alterations in the duodenum of male Wistar rats that received 20 ng/g TBT and 600 ng/g via gavage for 30 consecutive days. After the experimental period, the animals were euthanized, and the duodenum was intended for neuronal histochemistry (total and metabolically active populations) and histological routine (morphometry and histopathology). The results showed more severe changes in neuronal density and intestinal morphometry in rats exposed to 20 ng/g, such as total neuronal density decrease and reduction of intestinal layers. In rats exposed to 600 ng/g of TBT, it was possible to observe only an increase in intraepithelial lymphocytes. We conclude that TBT can be more harmful to intestinal homeostasis when consumed in lower concentrations.

Nano-Selenium Alleviates Cd-Induced Chronic Colitis through Intestinal Flora

BACKGROUND

Cadmium (Cd) is an environmental contaminant that poses risks to human and animal health. Selenium (Se), a beneficial element, alleviates the detrimental consequences of colitis and Cd toxicity. Se is found in food products as both inorganic Se (sodium selenite) and organic Se (typically Se-enriched yeast). Nano-selenium (nano-Se; a novel form of Se produced through the bioreduction of Se species) has recently garnered considerable interest, although its effects against Cd-induced enterotoxicity are poorly understood. The aim of this study was to investigate the impact of nano-selenium on mitigating cadmium toxicity and safeguarding the integrity of the intestinal barrier.

METHODS

For a total of two cycles, we subjected 6-week-old C57 mice to chronic colitis by exposing them to Cd and nano-selenium for two weeks, followed by DSS water for one week.

RESULTS

The application of nano-selenium mitigated the intensity of colitis and alleviated inflammation in the colon. Nano-selenium enhanced the diversity of the intestinal flora, elevated the concentration of short-chain fatty acids (SCFAs) in feces, and improved the integrity of the intestinal barrier.

CONCLUSIONS

In summary, nano-Se may reduce intestinal inflammation by regulating the growth of intestinal microorganisms and protecting the intestinal barrier.

Long-term Cu exposure alters CYP450s activity and induces jejunum injury and apoptosis in broilers

Copper (Cu) is an essential trace element that plays a crucial role in numerous physiopathological processes related to human and animal health. In the poultry industry, Cu is used to promote growth as a feed supplement, but excessive use can lead to toxicity on animals. Cytochrome P450 enzymes (CYP450s) are a superfamily of proteins that require heme as a cofactor and are essential for the metabolism of xenobiotic compounds. The purpose of this study was to explore the influence of exposure to Cu on CYP450s activity and apoptosis in the jejunum of broilers. Hence, we first simulated the Cu exposure model by feeding chickens diets containing different amounts of Cu. In the present study, histopathological observations have revealed morphological damage to the jejunum. The expression levels of genes and proteins of intestinal barrier markers were prominently downregulated. While the mRNA expression level of the gene associated with CYP450s was significantly increased. Additionally, apoptosis-related genes and proteins (Bak1, Bax, Caspase-9, Caspase-3, and CytC) were also significantly augmented by excessive Cu, while simultaneously decreasing the expression of Bcl-2. It can be concluded that long-term Cu exposure affects CYP450s activity, disrupts intestinal barrier function, and causes apoptosis in broilers that ultimately leads to jejunum damage.

Metabolomics study reveals increased deoxycholic acid contributes to deoxynivalenol-mediated intestinal barrier injury

AIMS

Deoxynivalenol (DON), namely vomitoxin, is one of the most prevalent fungal toxins in cereal crops worldwide. However, the underlying toxic mechanisms of DON remain largely unknown.

MAIN METHODS

DON exposure-caused changes in the murine plasma metabolome and gut microbiome were investigated by an LC-MS/MS-based nontargeted metabolomics approach and sequencing of 16S rRNA in fecal samples, respectively. Cellular models were then used to validate the findings from the metabolomics study.

KEY FINDINGS

DON exposure increased intestinal barrier permeability evidenced by its-mediated decrease in colonic Claudin 5 and E-cadherin, as well as increases in colonic Ifn-γ, Cxcl9, Cxcl10, and Cxcr3. Furthermore, DON exposure resulted in a significant increase in murine plasma levels of deoxycholic acid (DCA). Also, DON exposure led to gut microbiota dysbiosis, which was associated with DON exposure-caused increase in plasma DCA. In addition, we found not only DON but also DCA dose-dependently caused a significant increase in the levels of IFN-γ, CXCL9, CXCL10, and/or CXCR3, as well as a significant decrease in the expression levels of Claudin 5 and/or E-cadherin in the human colonic epithelial cells (NCM460).

SIGNIFICANCE

DON-mediated increase in DCA contributes to DON-caused intestinal injury. DCA may be a potential therapeutic target for DON enterotoxicity.

Transcriptome Analysis of Deoxynivalenol (DON)-Induced Hepatic and Intestinal Toxicity in Zebrafish: Insights into Gene Expression and Potential Detoxification Pathways

The effects of deoxynivalenol (DON, 50 µg/mL) on the zebrafish liver and intestine were studied. Differentially expressed genes (DEGs) from mRNA and lncRNA were analyzed by RNA seq. Gene Ontology (GO) and signaling pathways were studied where the top 30 DEGs of each type of RNA were involved. The results showed there were 2325 up-regulated and 934 down-regulated DEGs of lncRNA in the intestinal tract, and 95 up-regulated genes and 211 down-regulated genes in the liver, respectively. GO functional annotation analysis showed that lncRNA was enriched in the biological processes, involving the RNA splicing, CSF1-CSF1R complexes, and MAP kinase activity. DEGs of lncRNA located in the KEGG signal pathways include the C-type lectin receptor signaling and the NOD-like receptor signaling pathways. Metabolism involves the biosynthesis of indole alkaloids, cancer pathways for human disease, MAPK and Rap1signaling pathways for environmental information processing, necroptosis and focal adhesion for cell processes. The mRNA gene expression analysis showed there were 1939 up-regulated, 1172 down-regulated genes and 866 up-regulated, 1211 down-regulated genes in the intestine and liver of zebrafish, respectively. This study provides transcriptome analysis and toxicological investigation of DON in the zebrafish liver and intestine, offering insights into gene expression patterns and potential detoxification pathways.

Mycotoxin deoxynivalenol-induced intestinal flora disorders, dysfunction and organ damage in broilers and pigs

Deoxynivalenol (DON) is a common environmental contaminant that causes food refusal and growth retardation in animals. DON targets the intestine and is hazardous to animal, however, it is not clear whether its effect on animals is consistent. Chickens and pigs are the two main animals affected by DON exposure with different susceptibilities. In this study, we found that DON inhibited animal growth and caused damage to the intestine, liver and kidney. DON caused intestinal flora disorders in both chickens and pigs, such as changes of flora diversity and the relative abundance of dominant phyla. Functional analysis showed that changes in the intestinal flora induced by DON were mainly related to metabolic and digestive functions, indicated that the intestinal flora may be associated with the DON-induced intestinal dysfunction. Comparative analysis of differentially altered bacteria suggested that Prevotella may play an important role in maintaining intestinal health, and the presence of differentially altered bacteria in the two animals suggested that DON may have different toxicity modes in animals. In summary, we confirmed the multi-organ toxicity of DON in two major livestock and poultry animals, and speculated that the intestinal flora may be related to the toxic damage caused by DON through species comparison analysis.

Dose and route dependent effects of the mycotoxin deoxynivalenol in a 3D gut-on-a-chip model with flow

Deoxynivalenol (DON) is the most prevalent mycotoxin in human food and is ubiquitously detected in human bodyfluids. DON leads to intestinal barrier dysfunction, as observed from animal- and cell culture models with the known disadvantages. Here we present the effects of DON in a gut-on-a-chip model, as the first study incorporating the effects of intestinal flow. Using the OrganoPlate 3-lane, Caco-2 cells were seeded against an extracellular matrix (ECM) and formed leak tight tubules. DON was then applied in different concentrations (3 μM to 300 μM) via the apical or the basolateral channel. Permeability was assessed using continuous TEER and barrier integrity assays (BIA). Zonulin-1, toxicity (LDH) and proinflammatory status (IL-8) was analyzed. DON exposure led to a dose dependent decrease in para-and transcellular barrier integrity, which was more sensitive to basal than apical application (route). Timelaps/Continuous TEER measurements however revealed bidirectional effects, with even TEER-inducing effects of lower concentrations (until 10 μM). IL-8 secretion into luminal supernatants was only induced by apical DON. Attributed to the flow, the barrier-disintegrating effects of DON start at higher concentrations than in other culture models. The barrier was more sensitive to basolateral DON, even though DON had to pass the ECM; and IL-8 secretion was independent of TEER-alterations. Thus, the gut-on-a chip model might be a good alternative to further characterize the bidirectional effects of DON with reasonable throughput incorporating flow.

Deoxynivalenol induces intestinal injury: insights from oxidative stress and intestinal stem cells

Mycotoxins are fungal secondary metabolites that frequently occur in human and animal diets. Deoxynivalenol (DON) is one of the most widely occurring mycotoxins globally and poses significant harm to the animal husbandry industry and human health. People are increasingly aware of the adverse effects of DON on vulnerable structures and functions in the intestine, especially in the field of intestinal stem cells (ISCs). In this review, we present insights into DON that induces oxidative stress and affects the expansion of ISCs. Related studies of strategies for reducing its harm are summarized. We also discussed promising approaches such as regulation of microbiota, molecular docking, and modulation of the redox status via reducing the expression of Keap1 protein and single-cell sequencing, which may be critical for further revealing the mechanism of DON that induces oxidative stress and affects the expansion of ISCs.

Arsenic and iron bioavailability in Caco-2 cells: The influence of their co-existence and concentration

Arsenic (As) exposure in humans is primarily caused through food and drinking water. Iron (Fe) is one of the most common element of the human and can influence the toxicity and bioavailability of As. However, information on the interaction between As and Fe when present together is limited. In this study, the interaction effects of Fe(III) (0, 3, and 10 mg/L) and As (As(III) at 0, 0.05, 0.1 mg/L, and As(V) at 0, 0.1, and 2 mg/L, respectively) on their absorption and bioavailability in Caco-2 cells were analyzed. As(III) absorption significantly decreased with the addition of Fe, while Fe absorption significantly increased. Compared with 0.1 mg/L As(III) addition alone, 3 and 10 mg/L Fe(III) addition significantly reduced the As(III) absorption by 8.6 and 11 μg/L, respectively. The absorption of As and Fe(III) and the bioavailability of Fe(III) significantly increased with the addition of As(III/V). Compared with 10 mg/L Fe(III) alone, the absorption of As(III) was significantly increased by 1 and 1.3 mg/L with 0.05 and 0.1 mg/L As(III) addition, respectively. Furthermore, the absorption and bioavailability of Fe(III) were significantly increased by 1.2 mg/L and 8% and 1.2 mg/L and 8.2%, respectively, after adding 0.1 and 2 mg/L As(V).

Lactobacillus plantarum and Deoxynivalenol Detoxification: A Concise Review

ABSTRACT

Mycotoxins are toxic secondary fungal metabolites that contaminate feeds, and their levels remain stable during feed processing. The economic impact of mycotoxins on animal production happens mainly due to losses related to direct effects on animal health and trade losses related to grain rejection. Deoxynivalenol (DON) is a trichothecene mycotoxin that has contaminated approximately 60% of the grains worldwide. Ingestion of DON induces many toxic effects on human and animal health. Detoxification strategies to decrease DON levels in food and feeds include physical and chemical methods; however, they are not very effective when incorporated into the industrial production process. A valuable alternative to achieve this aim is the use of lactic acid bacteria. These bacteria can control fungal growth and thus overcome DON production or can detoxify the mycotoxin through adsorption and biotransformation. Some Lactobacillus spp. strains, such as Lactobacillus plantarum, have demonstrated preventive effects against DON toxicity in poultry and swine. This beneficial effect is associated with a binding capacity of lactic acid bacteria cell wall peptidoglycan with mycotoxins. Moreover, several antifungal compounds have been isolated from L. plantarum supernatants, including lactic, acetic, caproic, phenyl lactic, 3-hydroxylated fatty, and cyclic dipeptide acids. Biotransformation of DON by L. plantarum into other products is also hypothesized, but the mechanism remains unknown. In this concise review, we highlight the use of L. plantarum as an alternative approach to reduce DON levels and toxicity. Although the action mechanism of L. plantarum is still not fully understood, these bacteria are a safe, efficient, and low-cost strategy to reduce economic losses from mycotoxin contamination cases.

HIGHLIGHTS

Aflatoxin B1 disrupts the intestinal barrier integrity by reducing junction protein and promoting apoptosis in pigs and mice

With the growing diversity and complexity of diet, animals and humans are at risk of exposure to aflatoxin B1 (AFB1), which is a well-known contaminant in the food chain that causes various toxicological effects. The intestine acts as the first barrier against external contaminants, but the effect of AFB1 on intestinal barrier has not been determined. This study aimed to evaluate AFB1 on the intestinal barrier function in vitro and in vivo. In vitro, porcine jejunal epithelial cells (IPEC-J2) were treated with increasing concentrations of AFB1 (10-60 mg/L). In vivo, Kunming (KM) mice were used as controls or gavaged with 1% dimethyl sulfoxide (110 mg/kg b.w.) and AFB1 (0.3 mg/kg b.w.) for 28 days. In IPEC-J2 cells, the cell viability decreased with increasing mycotoxin concentrations, and the viability of IPEC-J2 cells decreased significantly (P < 0.05) when the AFB1 concentrations were greater than 30 mg/L. In addition, quantitative real-time PCR, Western blot analysis, and immunofluorescence results show that AFB1 can downregulate the tight junction proteins and increase the expression levels of Caspase-3 and the ratio of Bax/Bcl-2, suggesting that AFB1 was cytotoxic to IPEC-J2. In vivo, the ratio of villus height to crypt depth, the intestinal wall thickness, the number of intestinal villus per 1000 µm in the jejunum, the expression levels of ZO-1, Claudin-3, Occludin, MUC2, and Caspase-3, and the ratio of Bax/Bcl-2 were significantly affected in mice exposed to AFB1. In vitro and in vivo results showed that the effects of exposure to AFB1 on the intestinal function in the jejunum of KM mice and in the IPEC-J2 was similar, suggesting that AFB1 may adversely affect animal intestine.

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.

Combined toxicity of food-borne mycotoxins and heavy metals or pesticides

Food can be contaminated by multiple classes of toxic substances, mainly including mycotoxins, heavy metals and pesticides, which leads to a possibility of simultaneous exposure to two or more food contaminants for humans. Thus, it is necessary to examine whether the combined exposure could result in enhanced toxicity. Initially, the studies on the combined toxicity of food contaminants mainly focus on the mixtures of same classes of food contaminants due to their co-occurrence feature in foodstuffs, such as mixtures of mycotoxins or mixtures of heavy metals. Given the possibility that consumers are likely exposed to mixtures of different classes of food contaminants, recently, studies on the combined toxicity of different classes of food contaminants have been receiving increasing attentions. In this review article, we summarize the findings of combined toxicity studies related to co-exposure to food-borne mycotoxins and other classes of food contaminants mainly heavy metals or pesticides, and propose issues that need to be addressed in future studies for more accurately performing risk assessment of co-exposure to mycotoxins and other classes of food contaminants.

Combined effects of cadmium and ochratoxin A on intestinal barrier dysfunction in human Caco-2 cells and pig small intestinal epithelial cells

Hazardous chemicals are commonly found in cereals and cereal-based products. However, most studies focus on the individual effects of these mycotoxins or metals, rather than their combined toxicity. The main objective of this study was to evaluate the combined effects of cadmium (Cd) and ochratoxin A (OTA) on intestinal barrier integrity using Caco-2 cells and pig small intestinal epithelial (PSI) cells as models of intestinal epithelial cells and to measure alterations in cell survival and barrier integrity. The combined effects on cell viability were assessed in terms of a combination of index values. These findings showed that co-exposure to Cd + OTA had synergistic effects on Caco-2 and PSI cells at 25%, 50%, and 75% inhibitory concentrations (IC₂₅, IC₅₀, and IC₇₅, respectively) against cell viability. Individual Cd and OTA treatments had no effect, but combined Cd + OTA exposure resulted in synergistic down-regulation of paracellular apical junction complex proteins, such as claudin-1, occludin, and E-cadherin. The current findings indicate that the combined effects of OTA + Cd may have consequences at the gut level, which should not be underestimated when considering their risk to human health.

Low dose of arsenic exacerbates toxicity to mice and IPEC-J2 cells exposed with deoxynivalenol: Aryl hydrocarbon receptor and autophagy might be novel therapeutic targets

Deoxynivalenol (DON) and arsenic (As) are widespread environmental contaminants, which are frequently found in human and animal food products. The intestine is a common target of As and DON when they are digested. Numerous studies mainly evaluate the individual effects whereas their combined toxicity has rarely been elucidated. Hence, this study was to assess the effect of low dose of NaAsO₂ on DON-induced intestinal damage and explore the underling mechanism in mice and IPEC-J2 cells. The results showed that low dose of NaAsO₂ exacerbated DON-induced intestinal impairment by increasing intestinal permeability and decreasing the abundance of tight junction proteins (ZO-1, Occludin, Claudin-1). Further, low dose of NaAsO₂ enhanced the AhR signaling pathway and autophagy-related mRNA/protein expressions induced by DON. Interestingly, FICZ, an AhR activator, instead of CH223191, an AhR inhibitor, could alleviate toxicity of the low dose of NaAsO₂ in the mice and IPEC-J2 cells. Compared to the WT IPEC-J2 cells, the intestinal barrier damage was more serious in LC3B^-/- IPEC-J2 cells induced by low dose of NaAsO₂ combination with DON. Collectively, our study demonstrated that low dose of NaAsO₂ exacerbated DON-induced intestinal barrier impairment in vivo and in vitro. The present study also demonstrated that activation of AhR-mediated autophagy might be a self-protection mechanism. Hence, AhR and autophagy might be novel therapeutic targets to prevent or alleviate NaAsO₂ combined with DON-induced intestinal barrier impairment.

The foodborne contaminant deoxynivalenol exacerbates DNA damage caused by a broad spectrum of genotoxic agents

Humans are exposed to different contaminants including mycotoxins. Deoxynivalenol (DON), a potent ribosome inhibitor, is a highly prevalent mycotoxin in the food chain worldwide. Although DON is not genotoxic, we previously showed that it exacerbates the genotoxicity of colibactin, a DNA-crosslinking toxin produced by bacteria in the gut. In the present study, we investigated whether this phenotype can be extended to other genotoxic compounds with different modes of action. Our data showed that, at a dose that can be found in food, DON exacerbated the DNA damage caused by etoposide, cisplatin and phleomycin. In contrast, de-epoxy-deoxynivalenol (DOM-1), a modified form of DON that does not induce ribotoxic stress, did not exacerbate DNA damage. The effect of DON was mimicked with other ribosome inhibitors such as anisomycin and cycloheximide, suggesting that ribotoxicity plays a key role in exacerbating DNA damage. In conclusion, a new effect of DON was identified, this toxin aggravates the DNA damage induced by a broad spectrum of genotoxic agents with different modes of action. These results are of utmost importance as our food can be co-contaminated with DON and DNA-damaging agents.

Structure-toxicity relationships, toxicity mechanisms and health risk assessment of food-borne modified deoxynivalenol and zearalenone: A comprehensive review

Mycotoxin, as one of the most common pollutants in foodstuffs, poses great threat to food security and human health. Specifically, deoxynivalenol (DON) and zearalenone (ZEN)-two mycotoxin contaminants with considerable toxicity widely existing in food products-have aroused broad public concerns. Adding to this picture, modified forms of DON and ZEN, have emerged as another potential environmental and health threat, owing to their higher re-transformation rate into parent mycotoxins inducing accumulation of mycotoxin in humans and animals. Given this, a better understanding of the toxicity of modified mycotoxins is urgently needed. Moreover, the lack of toxicity data means a proper risk assessment of modified mycotoxins remains challenging. To better evaluate the toxicity of modified DON and ZEN, we have reviewed the relationship between their structures and toxicities. The toxicity mechanisms behind modified DON and ZEN have also been discussed; briefly, these involve acute, subacute, chronic, and combined toxicities. In addition, this review also addresses the global occurrence of modified DON and ZEN, and summarizes novel methods-including in silico analysis and implementation of relative potency factors-for risk assessment of modified DON and ZEN. Finally, the health risk assessment of modified DON and ZEN has also been discussed comprehensively.

Distribution, toxicity, interactive effects, and detection of ochratoxin and deoxynivalenol in food: A review

Mycotoxins are secondary metabolites of fungi that cause severe damage to agricultural products and food in the food supply chain. These detrimental pollutants have been directly linked with poor socioeconomic patterns and human health issues. Among the natural micropollutants, ochratoxin A (OTA) and deoxynivalenol (DON) are widely distributed in food materials. The primary occurrence of these mycotoxins is reported in almost all cereal grains and fresh agro-products. Both mycotoxins have shown harmful effects, such as nephrotoxic, hepatotoxic, and genotoxic effects, in humans due to their complex structural formation during the degradation/acetylation reaction. In addition, improper preharvest, harvest, and postharvest handling tend to lead to the formation of OTA and DON in various food commodities, which allows different harmful fungicides in practice. Therefore, this review provides more insight into the distribution and toxicity of OTA/DON in the food matrix and human health. Furthermore, the interactive effects of OTA/DON with co-contaminated organic and inorganic compounds are discussed. Finally, international regulation and mitigation strategies for detoxication are critically evaluated to meet food safety and good agriculture practices.

MicroRNA Expression Profiling in Porcine Liver, Jejunum and Serum upon Dietary DON Exposure Reveals Candidate Toxicity Biomarkers

Deoxynivalenol (DON), a frequent mycotoxin worldwide, impairs human and animal health. The response of microRNAs, small non-coding RNAs, to DON has been scarcely investigated, but holds remarkable potential for biomarker applications. Hence, we aimed to investigate DON-induced changes in the microRNA expression in porcine liver, jejunum and serum by combining targeted and untargeted analyses. Piglets received uncontaminated feed or feed containing 900 µg/kg and 2500 µg/kg DON for four weeks, followed by a wash-out period. In tissue, only slight changes in microRNA expression were detected, with ssc-miR-10b being downregulated in liver of DON-exposed piglets. In serum, several microRNAs were differentially expressed upon DON exposure, four of which were validated by qPCR (ssc-miR-16, ssc-miR-128, ssc-miR-451, ssc-miR-205). The serum microRNA response to DON increased over time and declined after removal of contaminated diets. Receiver operating curve analyses for individual microRNAs were significant, and a combination of the four microRNAs increased the predictive capacity for DON exposure. Predicted microRNA target genes showed enrichment of several pathways including PIK3-AKT, Wnt/β-catenin, and adherens junctions. This study gives, for the first time, a comprehensive view of the porcine microRNA response to DON, providing a basis for future research on microRNAs as biomarkers for mycotoxins.

Dietary Exposure to the Food Contaminant Deoxynivalenol Triggers Colonic Breakdown by Activating the Mitochondrial and the Death Receptor Pathways

INTRODUCTION

The food contamination by mycotoxins is of increasing public health concerns. Deoxynivalenol (DON), a mycotoxin contaminating cereals, has been associated with the exacerbation of inflammatory bowel diseases (IBD), thereby raising the question of its role in the development of IBD. Moreover, the effect of DON on the colon is poorly described.

METHODS AND RESULTS

Wistar rats exposed (1-4 weeks) to low doses of DON (2 or 9 mg kg^-1 feed) show microscopic alterations of colonic tissue (dilated lymphatic vessels, luminal debris, and cubic and flattened enterocytes). Ingestion of DON also alters colonic functions by increasing paracellular permeability while reducing the expression of the tight junction proteins and increased apoptosis in colonic tissue. Pro-apoptotic factors Bax/Bak, cytochrome C, and caspase 9 are upregulated, whereas expression of anti-apoptotic protein Bcl2 tends to decrease for the mitochondrial pathway. An increased expression of FasR and caspase-8 is observed for the extrinsic pathway. An increase in the pro-inflammatory markers TNFα, IL-17, and myeloperoxidase is also observed.

CONCLUSION

These results indicate that the dietary exposure to low levels of DON in food targets the colon inducing a health-threatening breakdown of the colonic barrier, highlighting oral exposure to DON as a potential risk factor in triggering IBD.

Lactobacillus plantarum metabolites reduce deoxynivalenol toxicity on jejunal explants of piglets

The deterioration of food and feed stuffs and toxic intestinal effects due to fungal colonization and concomitant production of mycotoxins is an increasing concern. The development of fungi resistance to many commonly used chemical preservatives adds further alarm. Therefore, effective detoxification methods would be useful in counteracting this problem. Biotransformation/adsorption of mycotoxins by lactic acid bacteria and their metabolites is a promising approach to minimize the deleterious effects of mycotoxins. The objective of the present study was to evaluate the beneficial effects of Lactobacillus plantarum metabolites in reducing deoxynivalenol intestinal toxicity. To achieve this aim, histological, morphometrical and oxidative stress analyses were performed in the intestinal mucosa of piglets exposed to deoxynivalenol alone or associated with two strains (SN1 and SN2) of L. plantarum subsp. plantarum metabolites. Metabolites were obtained after dichloromethane (D) or ethyl acetate (A) extraction. Jejunal explants were exposed to the following treatments for 2 and 4 h a) culture medium (control group); b) deoxynivalenol (DON, 10 μM); c) L. plantarum metabolites DSN1; d) L. plantarum metabolites DSN1+DON; e) L. plantarum metabolites DSN2; f) L. plantarum metabolites DSN2+DON; g) L. plantarum metabolites ASN1; h) L. plantarum metabolites ASN1+DON; i) L. plantarum metabolites ASN2; j) L. plantarum metabolites ASN2+DON. The metabolites were incubated 1 h previously to DON challenge (one and 3 h of exposure). Histological assessment showed DON-treated explants with villi fusion and atrophy, multifocal apical necrosis and cuboid or flattened enterocytes with 2 and 4 h of exposure, while LP metabolites groups individually or associated with DON remained like control. The density of goblet cells in villi and crypts was reduced in DON explants compared to control group with 2 and 4 h of exposure; on the other hand, a significant increase in this parameter was achieved in LP metabolites groups compared to DON. Morphometric evaluation showed no difference in villi height or crypts depth in any treated explants. Overall, oxidative stress response assessments showed that explants exposed to SN1 extracted with dichloromethane and ethyl acetate, and SN2 extracted with dichloromethane reduced superoxide anion production. In conclusion, L. plantarum metabolites induced beneficial effects in intestinal mucosa, reducing the toxic effects of DON on intestinal morphology and oxidative response.

In Vitro Analysis of Deoxynivalenol Influence on Steroidogenesis in Prostate

Deoxynivalenol (DON) is a type-B trichothecene mycotoxin produced by Fusarium species, reported to be the most common mycotoxin present in food and feed products. DON is known to affect the production of testosterone, follicle stimulating hormone (FSH) and luteinizing hormone (LH) in male rats, consequently affecting reproductive endpoints. Our previous study showed that DON induces oxidative stress in prostate cancer (PCa) cells, however the effect of DON on the intratumor steroidogenesis in PCa and normal prostate cells was not investigated. In this study human normal (PNT1A) and prostate cancer cell lines with different hormonal sensitivity (PC-3, DU-145, LNCaP) were exposed to DON treatment alone or in combination with dehydroepiandrosterone (DHEA) for 48 h. The results of the study demonstrated that exposure to DON alone or in combination with DHEA had a stimulatory effect on the release of estradiol and testosterone and also affected progesterone secretion. Moreover, significant changes were observed in the expression of genes related to steroidogenesis. Taken together, these results indicate that DON might affect the process of steroidogenesis in the prostate, demonstrating potential reproductive effects in humans.

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.

Low doses of imidacloprid induce disruption of intercellular adhesion and initiate proinflammatory changes in Caco-2 cells

Imidacloprid is the most widely used pesticide of the neonicotinoid class. Neonicotinoid toxicities against various insects are well known. Nevertheless, there are rising evidences that neonicotinoids exert cytotoxic effects on different non-target organisms including mammals, fish, birds etc. Besides, depending on pesticide application, the exposed plants absorb some part of used neonicotinoids and their residues are detected in agricultural products worldwide. Thus, the continuous consumption of fruits and vegetables contaminated with neonicotinoids is a high risk factor for humans despite the low doses. Intestine epithelial cells are the first targets of the neonicotinoid cytotoxicity in humans because of its direct way of administration. The epithelial cells provide the barrier function of the intestinal system via specialized intercellular adhesion. The effects of imidacloprid on the intestine barrier function and inflammatory cytokines production are still unknown. In the present study, we exposed the human Caucasian colon adenocarcinoma (Caco-2) epithelial cells to low doses (0.10–0.75 µg/mL) of imidacloprid in order to assess the expression of tight and adherens junctions proteins, occludin and E-cadherin, and production of proinflammatory cytokine TNF α and iNOS. Imidacloprid induced dose-dependent decline in both occludin and E-cadherin levels. By contrast, TNF-α and iNOS contents were upregulated in imidacloprid-exposed Caco-2 cells. Decrease in tight and adherens junctions proteins indicates that the barrier function of intestine epithelial cells could be damaged by imidacloprid administration. In addition, TNF-α and iNOS upregulation indicates that imidacloprid is potent to activate proinflammatory response in enterocytes. Thus, imidacloprid can affect intestine barrier function through the increase of proinflammatory cytokine production and decrease in adhesiveness of enterocytes. The further assessment of the role of adhesion proteins and inflammatory cytokines in neonicotinoid pesticide cytotoxicity as it affects enterocyte barrier function is required to highlight the risk factor of use of neonicotinoids.

Development of a living mammalian cell-based biosensor for the monitoring and evaluation of synergetic toxicity of cadmium and deoxynivalenol

With increased interest in the toxic interactions of multiple toxins, biotoxicity models have to be urgently developed for joint toxicity evaluation. This study aimed to develop an optical biosensor based on living mammary cells for monitoring of cadmium (Cd)/deoxynivalenol (DON) in water and evaluating their combined toxicity. Our previous survey found that DON and Cd appeared simultaneously in various products, and RNA seq revealed that AP-1 participated in combined toxicity of DON+Cd in HT-29 cells. Thus AP-1 site-mCherry-based biosensors were constructed, optimized, and then tested for their applicability and stable fluorescence response activities. DON+Cd²⁺, DON, and Cd²⁺ induced dose-dependent fluorescence signal in the biosensors (at environmental exposure levels). The enhanced fluorescence signal suggested that the toxicity of DON+Cd²⁺ was enhanced compared with that of single toxin. The advantages of the biosensors include: I) The easy and visual screening of multiple toxins on the basis of environmental exposure levels; II) Potential as a broad-spectrum tool for joint toxicity evaluation of DON+Cd; III) Pollution-free and stable fluorescence response; IV) A slight effect on viability.

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.

Mechanism of deoxynivalenol mediated gastrointestinal toxicity: Insights from mitochondrial dysfunction

Deoxynivalenol (DON) is a mycotoxin predominantly produced by Fusarium genus, and widely contaminates cereals and associated products all over the world. The intestinal toxicity of DON is well established. However, intestinal homeostasis involves mitochondria, which has rarely been considered in the context of DON exposure. We summarize the recent knowledge on mitochondria as a key player in maintaining intestinal homeostasis based on their functions in cellular energy metabolism, redox homeostasis, apoptosis, intestinal immune responses, and orchestrated bidirectional cross-talk with gut microbe. In addition, we discuss the pivotal roles of mitochondrial dysfunction in the intestinal toxicity of DON and highlight promising mitochondrial-targeted therapeutics for DON-induced intestinal injury. Recent studies support that the intestinal toxicity of DON is attributed to mitochondrial dysfunction as a critical factor. Mitochondrial dysfunction characterized by failure in respiratory capacities and ROS overproduction has been demonstrated in intestinal cells exposed to DON. Perturbation of mitochondrial respiration leading to ROS accumulation is implicated in the early initiation of apoptosis. DON-induced intestinal inflammatory response is tightly linked to the mitochondrial ROS, whereas immunosuppression is intimately associated with mitophagy inhibition. DON perturbs the orchestrated bidirectional cross-talk between gut microbe and host mitochondria, which may be involved in DON-induced intestinal toxicity.

Zearalenone and deoxynivalenol inhibited IL-4 receptor-mediated Th2 cell differentiation and aggravated bacterial infection in mice

The immunotoxicity of zearalenone (ZEA) and deoxynivalenol (DON), two of the most common environmental mycotoxins, has been well investigated. However, due to the complexity of the immune system, especially during bacterial infection, many types of immune cells are involved in invasion resistance and bacterial clearance. Of these, T helper 2 (Th2) cells, which are members of the helper T cell family, assist B cells to activate and differentiate into antibody-secreting cells, participate in humoral immune response, and, ultimately, eliminate pathogens. Thus, it is important to identify the stage at which these toxins affect the immune function, and to clarity the underlying mechanisms. In this study, mice infected with Listeria monocytogenes (Listeria) were used to study the effects of ZEA, DON, and ZEA + DON on Th2 differentiation, Interleukin-4 Receptor (IL-4R) expression, costimulatory molecules expression and cytokine secretion after Listeria infection. Naive CD4+ T cells, isolated from mice, were used to verify the in vivo effects and the associated mechanisms. In vivo experiments showed that these toxins aggravated spleen damage after Listeria infection and reduced the differentiation of Th2 cells by affecting the synthesis of IL-4R of CD4+ T cells. In addition, the level of the costimulatory molecule CD154 decreased. Consistent with this, in vitro studies showed that these toxins inhibited the differentiation of mouse naive CD4+ T cell into Th2 subtype and decreased IL-4R levels. In addition, the levels of costimulatory molecules CD154, CD278 and the Th2 cells secrete cytokines IL-4, IL-6, and IL-10 decreased. Based on our in vivo and in vitro experiments, we suggest that ZEA, DON, and ZEA + DON inhibit the expression of costimulatory molecules on CD4+ T cell, and inhibit the IL-4R-mediated Th2 cell differentiation. This may indicate that the body cannot normally resist or clear the pathogen after mycotoxin poisoning.

Aflatoxin B1 and Aflatoxin M1 Induce Compromised Intestinal Integrity through Clathrin-Mediated Endocytosis

With the growing diversity and complexity of diet, humans are at risk of simultaneous exposure to aflatoxin B1 (AFB1) and aflatoxin M1 (AFM1), which are well-known contaminants in dairy and other agricultural products worldwide. The intestine represents the first barrier against external contaminants; however, evidence about the combined effect of AFB1 and AFM1 on intestinal integrity is lacking. In vivo, the serum biochemical parameters related to intestinal barrier function, ratio of villus height/crypt depth, and distribution pattern of claudin-1 and zonula occluden-1 were significantly affected in mice exposed to 0.3 mg/kg b.w. AFB1 and 3.0 mg/kg b.w. AFM1. In vitro results on differentiated Caco-2 cells showed that individual and combined AFB1 (0.5 and 4 μg/mL) and AFM1 (0.5 and 4 μg/mL) decreased cell viability and trans-epithelial electrical resistance values as well as increased paracellular permeability of fluorescein isothiocyanate-dextran in a dose-dependent manner. Furthermore, AFM1 aggravated AFB1-induced compromised intestinal barrier, as demonstrated by the down-regulation of tight junction proteins and their redistribution, particularly internalization. Adding the inhibitor chlorpromazine illustrated that clathrin-mediated endocytosis partially contributed to the compromised intestinal integrity. Synergistic and additive effects were the predominant interactions, suggesting that these toxins are likely to have negative effects on human health.

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.

Relief of Cadmium-Induced Intestinal Motility Disorder in Mice by Lactobacillus plantarum CCFM8610

Cadmium (Cd) is a toxic metal inducing a range of adverse effects on organs including liver and kidneys. However, the underlying molecular mechanisms of Cd-induced intestinal toxicity through dietary intake is poorly studied. This study evaluated the toxic effects of Cd on intestinal physiology and confirmed the effectiveness of the protective mechanism of the probiotic Lactobacillus plantarum CCFM8610 against chronic Cd toxicity. After treatment with Cd, the HT-29 cell line was subjected to iTRAQ analysis, which revealed that changes in the proteomic profiles after Cd exposure were related to pathways involved in the stress response and carbohydrate metabolism. The results of an animal trial also indicated that 10 weeks of Cd exposure decreased the fecal water content and contractile response of colonic muscle strips in mice, and delayed the excretion time of the first black feces. L. plantarum CCFM8610 treatment provided protective effects against these Cd-induced intestinal motility dysfunctions by recovering the levels of neurotransmitters, including substance P, acetyl cholinesterase, vasoactive intestinal peptide, 5-hydroxytryptamine, calcitonin gene-related peptide, and nitric oxide, and suppressing the cellular stress response in mice (e.g., the inhibition of mitogen-activated protein kinase pathways). The administration of this probiotic was also observed to reduce Cd levels in the tissues and blood of the mice. Our results suggest a newly identified protective mechanism of probiotics against Cd toxicity that involves the recovery of intestinal motility and increase in fecal cadmium excretion.

Cadmium exacerbates dextran sulfate sodium-induced chronic colitis and impairs intestinal barrier

The potential health risk of environmental pollutant, cadmium, has become a public concern due to its widespread existence and long biological half-life. High-dose cadmium can induce various adverse outcomes, however, the chronic biological influences of cadmium at an environmental dosage and its mechanism remain largely unclear. Here, we investigated the effect of long-term exposure of cadmium at the environmental-relevant concentration on intestinal function. A chronic colitis mouse model was established through multiple cycles of dextran sulfate sodium (DSS) challenge and recovery. 200 nM cadmium in drinking water intensified colonic inflammation induced by DSS (histological score, DSS vs. DSS + Cd: 7.4 ± 1.21 vs. 10.67 ± 0.67, P < 0.05), including fecal occult bleeding and fecal consistency loss. Multiple inflammatory cytokines were significantly up-regulated by cadmium both in colon and plasma (P < 0.05). In addition, intestinal integrity was compromised by cadmium. Goblet cells were markedly reduced (ctrl vs. Cd: 48.33 ± 3.07 vs. 37.5 ± 2.14, P < 0.05) and plasma D-lactate (ctrl vs. Cd: 1.88 ± 0.20 vs. 2.80 ± 0.15, P < 0.01) and diamine oxidase (ctrl vs. Cd: 5.00 ± 0.87 vs. 11.21 ± 2.17, P < 0.05) were increased in cadmium-treated mice, indicating an elevated intestinal permeability. In vitro results showed that long-term exposure of cadmium down-regulated the expression and membrane localization of adherent and tight junction proteins in a time-dependent manner. In conclusion, long-term exposure of environmental dose of cadmium aggravated DSS-induced chronic colitis and disrupted intestinal barrier and impaired the adherent and tight junction proteins. These findings provide a better understanding about the health risk of cadmium in the environment.

Acute and subacute oral toxicity of deoxynivalenol exposure in a Dermatophagoides farinae induced murine asthma model

Previously, researchers have demonstrated that mycotoxin deoxynivalenol significantly enhances immunocyte activation. However, the interaction between deoxynivalenol exposure and immune disorders remains unclear. In this study, we aimed to investigate whether acute and subacute oral exposure to deoxynivalenol exacerbates the development of respiratory allergy using a mite allergen (Dermatophagoides farina, Derf)-induced mouse model of asthma. The direct relationship between deoxynivalenol exposure and asthma development was examined following acute oral deoxynivalenol administration (0, 0.1, or 0.3 mg/kg body weight), immediately before the final mite allergen challenge. Simultaneously, the influence of subacute oral exposure via low dose deoxynivalenol contaminated wheat (0.33 ppm) was evaluated using the same settings. To detect the pro-inflammatory effects of deoxynivalenol exposure, we examined the total and Derf-specific serum IgE levels, histology, number of immunocytes, and cytokine and chemokine secretion. Acute oral deoxynivalenol significantly enhanced the inflammatory responses, including cellular infiltration into bronchoalveolar lavage fluid, infiltration of immunocytes and cytokine production in local lymph nodes, and cytokine levels in lung tissues. Corresponding pro-inflammatory responses were observed in a mouse group exposed to subacute oral deoxynivalenol. In vivo results were validated by in vitro experiments using the human bronchial epithelial (BEAS-2B) and human eosinophilic leukemia (EOL-1) cell lines. Following exposure to deoxynivalenol, the secretion of interleukin (IL)-1β, IL-6, IL-8, and/or tumor necrosis factor (TNF)-α in BEAS-2B cells, as well as EoL-1 cells, increased significantly. Our findings indicate that deoxynivalenol exposure is significantly involved in the pro-inflammatory response observed in respiratory allergy.

Low-level contamination of deoxynivalenol: A threat from environmental toxins to porcine epidemic diarrhea virus infection

Mycotoxins are toxic metabolites produced by fungal species that commonly present in the global environment, especially in cereals and animal forages. The changing global environment may further increase the exposure to these toxins, posing a serious threat to humans and animals. Recently, coronavirus has become one of the most important pathogens threatening human and animal health. It is not clear whether environmental toxins, such as mycotoxins, will affect coronavirus infection. Given that pigs are among the animals most affected by coronavirus and highly homologous to humans, weaned piglets and IPEC-J2 cells were respectively chosen as in vivo and in vitro model to explore the impacts of deoxynivalenol (DON), the most abundant trichothecene mycotoxin in feed, on porcine epidemic diarrhea virus (PEDV) infection and the mechanisms involved. In vivo, twenty-seven piglets infected naturally with PEDV were randomly divided into three groups, receiving the basal diet containing 0, 750 and 1500 μg/kg DON, respectively. Significant increases in the diarrhea rates, gut barrier injury and PEDV proliferation of piglets' small intestine were observed in experimental groups compared with the control. Additionally, the autophagosome-like vesicles and the autophagy-related proteins expression were also increased in experimental groups. In vitro, we observed that 0.1, 0.5 and 1.0 μM DON significantly promoted the entry and replication of PEDV in IPEC-J2 cells, along with the induction of a complete autophagy. CRISPR-Cas9-mediated knockout of LC3B indicated a vital role of autophagy in the promotion. Pretreatment with p38 signaling inhibitor could significantly block the induction of autophagy, indicating that DON could promote the PEDV infection by triggering p38-mediated autophagy. Our findings suggest that mycotoxin could influence the prevalence of coronavirus and provide new ideas for the prevention and control of coronavirus.

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.

Structural and functional alterations of gut microbiome in mice induced by chronic cadmium exposure

Mammalian gut microbiome is readily affected by acute or subchronic cadmium (Cd) intoxication, but it susceptibility following chronic Cd exposure at environmentally-relevant levels remains unknown. This study comprehensively assessed the effects of Cd exposure at doses of 10 and 50 ppm in drinking water for 20 weeks on gut microbiome in mice. Results showed that the Cd exposure induced alterations in gut morphology with potentially increased gut permeability and inflammation. These changes were accompanied by marked perturbation of gut microbiota characterized by significantly decreased gut microbial richness and lowered abundance of short chain fatty acid (SCFA)-producing bacteria, resulting in reduced SCFAs production in the gut. Moreover, the Cd exposure caused substantial metabolic functional changes of the gut microbiome, with significant inhibitions on gene pathways associated with metabolism of amino acid, carbohydrate, and energy, as well as promotions on metabolic pathways such as glutathione metabolism and aminobenzoate degradation. Our findings provide new insights into the hazards assessment of environmental Cd exposure towards gut microbiome.

Association Between Mycotoxin Exposure and Dietary Habits in Colorectal Cancer Development Among a Polish Population: A Study Protocol

Colorectal cancer (CRC) is one of the most common and lethal types of cancer worldwide. The developing of this disease includes many factors such as genetic, socioeconomic, environmental, and lifestyle factors, and nutrition habits. The aim of the study is the determination of zearalenone and its metabolite level in the biological samples of participants at risk of CRC, in relation to the nutrition data and information on the quality of life dependent on health. In the cohort clinical trial, 150 participants aged between 50 and 65 will be studied. The participants will be assigned into two groups depending on the colonoscopy result. Participants will be tested at dietary intake, quality of life, sleep time and quality, stress level as well as biochemical parameters of the blood. Moreover, in the biological samples, concentration of zearalenone and its metabolites (α-zearalenol and β-zearalenol) as well as the characteristics of gastrointestinal bacterial will be determined, and the end of the trial for both groups and their results will be compared. Taking into account the possible effect of mycotoxins and nutrition habits on the development of cancer, the results obtained may allow the formulation of new nutritional recommendations and reduce the development and occurrence of CRC.