The Compromised Intestinal Barrier Induced by Mycotoxins

Glutamine Peptides: Preparation, Analysis, Applications, and Their Role in Intestinal Barrier Protection

Background: Glutamine peptides refer to a series of peptides containing glutamine, and the activity of glutamine peptides is characterized by the content of non-nitrogen terminal glutamine in the peptide. It has been found that glutamine peptides are a stable substitute for glutamine monomer, and they are increasingly studied in nutrition and physiology due to their functional properties. Methods: An extensive search of the literature was conducted in the PubMed, Web of Science, Scopus, and Google Scholar databases up to December 2024. Inclusion criteria focused on the role of glutamine peptides in intestinal health, and the included literature was screened and summarized. Results: This study systematically reviews the current status of research on the preparation, analysis, applications of glutamine peptides and their role in intestinal barrier protection. Furthermore, the challenges faced by the current research and the development direction in the future are discussed. Conclusions: Glutamine peptides can play a role in protecting the intestinal barrier by regulating tight junctions, mucin, inflammatory response, and intestinal flora. In addition, further and intensive investigations are urgently required to address the current challenges pertaining to the structure-activity relationships of glutamine peptides and their transport and absorption mechanism in the gut. This review contributes to a better understanding of the mechanism of glutamine peptides to protect intestinal barrier function and also provides a reference for the development of functional foods with protective effects of intestinal barrier function.

Low molecular weight galactomannan alleviates diarrhea induced by senna leaf in mice via intestinal barrier improvement and gut microbiota modulation

Low molecular weight galactomannan (LMGM), a soluble dietary fibre derived from guar gum, is recognized for its prebiotic functions, including promoting the growth of beneficial intestinal bacteria and the production of short-chain fatty acids, but the mechanism of alleviating diarrhea is not fully understood. This study established an acute diarrhea mouse model using senna leaf decoction and evaluated the therapeutic effects of LMGM by monitoring diarrhea scores, loose stool prevalence, intestinal tissue pathology and gene expression, and gut microbiota composition and metabolisms. The results indicated that LMGM significantly reduced diarrhea scores and loose stool prevalence within two hours post-treatment. Hematoxylin and eosin staining and quantitative real-time polymerase chain reaction analysis revealed that LMGM improved intestinal epithelial structure and up-regulated the expression of zonula occludens 1, occludin, mucin 2, aquaporin 3, and aquaporin 4 in ileum, jejunum, and colon tissues. Moreover, LMGM increased the abundance of beneficial bacteria such as Lactobacillaceae and Lachnospiraceae, and decreased Prevotellaceae in the cecum. Furthermore, LMGM promoted short-chain fatty acid production and reduced ammonia nitrogen and skatole concentrations in the intestinal content. The study suggests that LMGM could serve as a functional prebiotic for diarrhea alleviation, potentially by enhancing the intestinal barrier, modulating water transportation, and regulating the microbiota composition.

Exploring the therapeutic potential of Xiangsha Liujunzi Wan in Crohn's disease: from network pharmacology approach to experimental validation

ETHNOPHARMACOLOGICAL RELEVANCE

Xiangsha Liujunzi Wan (LJZW) is a traditional Chinese medicine (TCM) formula containing a variety of traditional Chinese herb components. Its principal components are often used in the treatment of gastrointestinal diseases and contribute to the treatment of Crohn's disease (CD).

AIM OF THE STUDY

To explore the therapeutic potential of LJZW in CD through network pharmacology, bioinformatics, molecular docking, and experimental verification.

METHODS

The principal bioactive components and corresponding targets of LJZW were ascertained from the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP). Potential targets for CD were identified in GeneCards, OMIM, DrugBank, DisGeNET, CTD, and Gene Expression Omnibus (GEO) databases. Intersection targets of LJZW and CD were identified using a Venn diagram and visualized using Cytoscape 3.8.0 to construct a protein-protein interaction (PPI) network. Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were employed to assess the function of intersection targets. AutoDockTools and PyMOL were used for molecular docking to recognize the association between the core ingredients of LJZW and the core targets of CD. Subsequently, a series of experiments were conducted for validation.

RESULTS

The network pharmacology results indicated that there were 156 bioactive components and 268 corresponding targets for LJZW, 3023 primary relevant targets for CD, and 169 intersection targets for LJZW and CD. The PPI network was employed to identify five hub genes and six clusters. The GO functional analysis indicated that intersection targets are primarily correlated with oxidative stress and inflammatory responses. KEGG pathway analysis revealed that these targets were primarily associated with the phosphotylinosital 3 kinase (PI3K)-protein kinase B (AKT) and mitogen-activated protein kinase (MAPK) signaling pathways. The molecular docking results showed that the core ingredients of LJZW had good binding ability with the core targets of CD. A series of experiments demonstrated that LJZW could effectively attenuate TNBS-induced colitis symptoms, inhibit the inflammatory response, and protect intestinal barrier function by inhibiting the PI3K-AKT and MAPK signaling pathways, thus preventing and treating CD.

CONCLUSION

LJZW has the characteristics of multi-component, multi-target, and multi-pathway treatment, which helps to improve the treatment of CD, protect the intestinal barrier, and exert the effect of anti-inflammatory therapy by inhibiting PI3K-AKT and MAPK signaling pathways.

Apical-out intestinal organoids as an alternative model for evaluating deoxynivalenol toxicity and Lactobacillus detoxification in bovine

Small intestinal organoids are similar to actual small intestines in structure and function and can be used in various fields, such as nutrition, disease, and toxicity research. However, the basal-out type is difficult to homogenize because of the diversity of cell sizes and types, and the Matrigel-based culture conditions. Contrastingly, the apical-out form of small intestinal organoids is relatively uniform and easy to manipulate without Matrigel. Therefore, we sought to investigate the possibility of replacing animal testing with bovine apical-out small intestinal organoids (Apo-IOs) by confirming the toxicity of mycotoxins and effectiveness of L. plantarum as mycotoxin-reducing agents. The characteristics and functions of Apo-IOs were first confirmed. The gene and protein expression of stem cell, proliferation, mucous, and adherence markers were detected, and the absorption capacity of amino and fatty acids was also confirmed. FITC-4 kDa dextran, a marker of intestinal barrier function, did not penetrate the Apo-IOs, confirming the role of the organoids as a barrier. However, when co-treated with deoxynivalenol (DON), FITC-4 kDa dextran was detected deep within the organoids. Moreover, qPCR and immunofluorescence staining confirmed a decrease in the expression of key markers, such as LGR5, Ki67, Mucin2, Villin2, and E-cadherin. In addition, when Apo-IOs were treated with Lactobacillus plantarum ATCC14917 culture supernatant (LCS) and DON together, cell death was reduced compared to when treated with DON alone, and FITC-4 kDa dextran was confirmed to flow only to the peripheral part of the organoid. The qPCR and immunofluorescence staining results of LCS and DON co-treatment group showed that LGR5, Ki67, Mucin2, Villin2, and E-cadherin were expressed at significant higher levels than those in the DON treatment group alone. In this study, we found that the characteristics and functions of bovine Apo-IOs were similar to those of the intestinal structure in vivo. Additionally, the effects of mycotoxins and effectiveness of L. plantarum as mycotoxin-reducing agents were confirmed using bovine Apo-IOs. Therefore, bovine Apo-IOs could be applied in toxicity studies of mycotoxins and could also be used as in vitro models to replace animal testing and improve animal welfare.

Interaction between ischemia-reperfusion injury and intestinal microecology in organ transplantation and its therapeutic prospects

Organ transplantation is a vital intervention for end-stage organ failure; however, ischemia-reperfusion injury is a complication of transplantation, affecting the prognosis and survival of transplant recipients. As a complex ecosystem, recent research has highlighted the role of the intestinal microecology in transplantation, revealing its significant interplay with ischemia-reperfusion injury. This review explores the interaction between ischemia-reperfusion injury and intestinal microecology, with a special focus on how ischemia-reperfusion injury affects intestinal microecology and how these microecological changes contribute to complications after organ transplantation, such as infection and rejection. Based on a comprehensive analysis of current research advances, this study proposes potential strategies to improve transplant outcomes, offering guidance for future research and clinical practice.

Phytochemical Characterization of Bilberries and Their Potential as a Functional Ingredient to Mitigate Ochratoxin A Toxicity in Cereal-Based Products

Mycotoxin contamination of cereals and cereal-based products is a serious problem for food safety. Antioxidant-rich ingredients such as bilberries (Vaccinium myrtillus L., VM) may mitigate their harmful effects. Firstly, total phenolic content, antioxidant activity, and analytical phytochemical composition (hydroxycinnamic and hydroxybenzoic acids, flavanols, flavonols, and anthocyanins) were assessed in lyophilized wild bilberries from Romania. Secondly, this study evaluated bilberries' effects on reducing ochratoxin A (OTA) bioaccessibility and cytotoxicity. An in vitro digestion model was developed and applied to four different types of bread: Control, VM (2%), OTA (15.89 ± 0.13 mg/kg), and OTA (16.79 ± 0.55 mg/kg)-VM (2%). The results indicated that VM decreased OTA bioaccessibility by 15% at the intestinal level. OTA-VM digests showed improved Caco-2 cell viability in comparison to OTA digests across different exposure times. Regarding the alterations in Jurkat cell line cell cycle phases and apoptosis/necrosis, significant increases in cell death were observed using OTA digests (11%), while VM addition demonstrated a protective effect (1%). Reactive oxygen species (ROS) analysis confirmed these findings, with OTA-VM digests showing significantly lower ROS levels compared to OTA digests, resulting in a 3.7-fold decrease. Thus, bilberries exhibit high potential as a functional ingredient, demonstrating protection in OTA mitigation effects.

Mitigation effects of plant carbon black on intestinal morphology, inflammation, antioxidant status, and microbiota in piglets challenged with deoxynivalenol

Introduction

Plant carbon black (PCB) is a new feed additive for zearalenone adsorption in China. However, information regarding whether PCB can effectively absorb deoxynivalenol (DON) is limited.

Methods

To explore this research gap, the present study examined the adsorption effectiveness of DON by PCB using a phosphate buffer, artificial gastric juice, and artificial intestinal juice. In a 21-day in vivo trial, 48 male piglets were randomly assigned to four treatment groups: (1) uncontaminated basal diet (CTR), (2) basal diet supplemented with 1 mg/kg PCB(PCB), (3) 2.3 mg/kg DON-contaminated diet (DON), and (4) 2.3 mg/kg DON-contaminated diet supplemented with 0.1% PCB (DON+PCB).

Results

When DON concentration was 1 µg/mL, the adsorption rate of PCB on DON in phosphate buffer systems (pH 2.0 and 6.0) and the artificial gastric and intestinal juices were 100%, 100%, 71.46%, and 77.20%, respectively. In the in vivo trial, the DON group significantly increased the DON+deepoxy-deoxynivalenol (DOM-1) content in serum as well as the inflammation cytokine proteins (interleukin-6, interleukin-8, and tumor necrosis factor-α) and mRNA expression of interleukin-6 and longchain acyl-CoA synthetase 4 in the jejunum and ileum. It decreased the villus height, goblet cells, mucosal thickness, and mRNA expression of Claudin-1 compared to the CTR group. In addition, DON decreased the Shannon and Simpson indices; reduced the relative abundances of Firmicutes, Lactobacillus, Candidatus_Saccharimonas, and Ruminococcus; and increased the relative abundances of Terrisporobacter and Clostridium_sensu_stricto_1 in the cecal content.

Discussion

In conclusion, these results suggest that PCB showed high adsorption efficacy on DON in vitro, and exhibit the protective effects against various intestinal toxicity manifestations in DON-challenged piglets.

The Mycotoxins T-2 and Deoxynivalenol Facilitate the Translocation of Streptococcus suis across Porcine Ileal Organoid Monolayers

Mycotoxins have the potential to increase the risk of airway or intestinal infection due to their effects on epithelial integrity and function. The bacterium Streptococcus suis (S. suis) is often carried in pigs and can cause outbreaks of invasive disease, leading to sepsis and meningitis in postweaning piglets. In this study, we tested the effect of two Fusarium mycotoxins (deoxynivalenol (DON) and T-2) on the integrity of the intestinal epithelium and their interaction with S. suis. Porcine ileal organoids were exposed to DON and T-2 individually or in combination and co-cultured with or without S. suis. Both DON and T-2 were toxic for ileal organoid monolayers at a concentration of 1 µM but not S. suis, even at a higher concentration of 4 µM. To mimic sub-clinical exposures on farms, DON was tested at a concentration of 0.1 µM and T-2 at a concentration of 0.01 µM. The mycotoxins alone did not affect cell permeability, but in combination with S. suis there was an increase in epithelial permeability. Furthermore, DON and T-2 together decreased the transepithelial electrical resistance and increased bacterial translocation.

Lauric acid reduces apoptosis by inhibiting FOXO3a-signaling in deoxynivalenol-treated IPEC-J2 cells

Deoxynivalenol (DON) is the most common mycotoxin contaminant of food or feed worldwide and causes disease in animals. Lauric acid (LA) is a medium-chain fatty acid useful for barrier functions such as antimicrobial activity in the intestine of monogastric animals. However, the molecular mechanisms by which lauric acid exerts its effects on the deoxynivalenol-exposed small intestine have not been studied. We used an intestinal porcine epithelial cell line (IPEC-J2) as an in vitro model to explore the molecular mechanism of lauric acid in alleviating deoxynivalenol-induced damage. We found that lauric acid reversed deoxynivalenol-induced reduction in cell viability. Our quantitative real-time polymerase chain reaction results indicated that lauric acid alleviated deoxynivalenol-induced apoptosis through Annexin-V. Additionally, immunofluorescence and Western blotting showed that lauric acid attenuated deoxynivalenol-induced forkhead box O3 (FOXO3a) translocation into the nucleus. These results suggest that lauric acid attenuates forkhead box O3 translocation in the small intestine damaged by deoxynivalenol, thereby reducing apoptosis. In conclusion, this study found that lauric acid alleviates deoxynivalenol-induced damage in intestinal porcine epithelial cell line through various molecular mechanisms.

Double-side role of short chain fatty acids on host health via the gut-organ axes

Short chain fatty acids (SCFA) exist in dietary foods and are produced by the fermentation of gut microbiota, and are considered an important element for regulating host health. Through blood circulation, SCFA produced in the gut and obtained from foods have an impact on the intestinal health as well as vital organs of the host. It has been recognized that the gut is the "vital organ" in the host. As the gut microbial metabolites, SCFA could create an "axis" connecting the gut and to other organs. Therefore, the "gut-organ axes" have become a focus of research in recent years to analyze organism health. In this review, we summarized the sources, absorption properties, and the function of SCFA in both gut and other peripheral tissues (brain, kidney, liver, lung, bone and cardiovascular) in the way of "gut-organ axes". Short chain fatty acids exert both beneficial and pathological role in gut and other organs in various ways, in which the beneficial effects are more pronounced. In addition, the beneficial effects are reflected in both preventive and therapeutic effects. More importantly, the mechanisms behinds the gut and other tissues provided insight into the function of SCFA, assisting in the development of novel preventive and therapeutic strategies for maintaining the host health.

Mycotoxins and coccidiosis in poultry - co-occurrence, interaction, and effects

Avian coccidiosis, a common disease caused by Eimeria species, results in significant losses in global poultry production. Mycotoxins are low-molecular-weight natural products (i.e., small molecules) produced as secondary metabolites by filamentous fungi and they have the potential to economically and significantly affect global poultry production. Little is known about the relationship between mycotoxins and avian coccidiosis, although they often co-occur in the field. This comprehensive review examines the intricate relationship between mycotoxins and avian coccidiosis, in particular how mycotoxins, including aflatoxins, ochratoxins, trichothecenes as well as Fusarium mycotoxins, compromise the health of the poultry flock and open the door to Eimeria parasites in the gut. In addition, this review sheds light on the immunosuppressive effects of mycotoxins, their disruption of cellular signaling pathways, and the consequent exacerbation of coccidiosis infections. The mechanisms of mycotoxin toxicity are also reviewed, emphasizing direct damage to intestinal epithelial cells, impaired nutrient absorption, inflammation, oxidative stress, and changes in the gut microbiota. Finally, the consequences for the prevention and treatment of coccidiosis when mycotoxins are present in the feed are discussed. This review emphasizes the need for effective management strategies to mitigate the combined risks of mycotoxins and coccidiosis and highlights the complexity of diagnosing and controlling these interrelated problems in poultry. The review advocates a holistic approach that includes strict feed management, disease prevention measures and regular monitoring to maintain the health and productivity of poultry against these significant challenges.

Multi-Omics Revealed Resveratrol and β-Hydroxy-β-methyl Butyric Acid Alone or in Combination Improved the Jejunal Function in Tibetan Sheep

Previous research studies confirmed that both resveratrol (RES) and β-hydroxy-β-methyl butyric acid (HMB) improved growth performance by altering intestinal microbiota. However, the mechanism underlying of RES and HMB on intestinal function remains unclear in ruminant. In this study, supplements of RES and HMB alone or in combination were evaluated as promoters of antioxidant capacity, immune response and barrier function, and modulators of the microbiota and metabolite profiles in the jejunum of Tibetan sheep. A total of 120 two-month-old Tibetan rams were randomly divided into four treatments (n = 30 per treatment), which were supplemented with a basal diet with 1.5 g RES/d (RES group), 1.25 g HMB/d (HMB group), 1.5 g RES/d plus 1.25 g HMB/d (RES-HMB group), and without additions (Control group). The results showed that RES and HMB improved the antioxidant capacity (CAT, GSH-Px, SOD, and T-AOC), immunity (IgA, IgG, and IgM), and digestive enzyme activity (α-amylase, lipase, and chymotrypsin) of the experimental lambs (p < 0.05). Additionally, jejunal morphology including villus width, villus height, and muscle layer thickness exhibited a significant difference when rams were fed diets supplemented with RES and HMB (p < 0.05). Furthermore, the determination of fermentation parameters showed that the butyrate concentration in the RES-HMB group was greater than those in the C and RES groups (p < 0.05). When compared to the C group, barrier-related gene expression (MUC-2, ZO-1, and IL-10) was significantly increased in the RES-HMB group (p < 0.05). Dietary RES and (or) HMB supplementation significantly increased the abundance of Methanobrevibacter, Actinobacteriota and Bacillus (p < 0.05). The abundance of differential bacteria was positively associated with butyrate concentration (p < 0.05). Metabolome analysis revealed that alpha ketoglutarate, succinic semialdehyde, and diacetyl as well as butanoate metabolism pathways connected to the improvements in butyrate concentration by RES and (or) HMB supplementation. Collectively, our results suggested that RES and (or) HMB supplementation improved butyrate concentration via regulating the microbial community (Methanobrevibacter, Actinobacteriota and Bacillus) and metabolism (alpha ketoglutarate, succinic semialdehyde, and diacetyl), thus contributing to jejunal morphology, antioxidant capacity, immune response, digestive enzyme activity, and barrier function.

Bioenzymatic detoxification of mycotoxins

Mycotoxins are secondary metabolites produced during the growth, storage, and transportation of crops contaminated by fungi and are physiologically toxic to humans and animals. Aflatoxin, zearalenone, deoxynivalenol, ochratoxin, patulin, and fumonisin are the most common mycotoxins and can cause liver and nervous system damage, immune system suppression, and produce carcinogenic effects in humans and animals that have consumed contaminated food. Physical, chemical, and biological methods are generally used to detoxify mycotoxins. Although physical methods, such as heat treatment, irradiation, and adsorption, are fast and simple, they have associated problems including incomplete detoxification, limited applicability, and cause changes in food characteristics (e.g., nutritive value, organoleptic properties, and palatability). Chemical detoxification methods, such as ammonification, ozonation, and peroxidation, pollute the environment and produce food safety risks. In contrast, bioenzymatic methods are advantageous as they achieve selective detoxification and are environmentally friendly and reusable; thus, these methods are the most promising options for the detoxification of mycotoxins. This paper reviews recent research progress on common mycotoxins and the enzymatic principles and mechanisms for their detoxification, analyzes the toxicity of the degradation products and describes the challenges faced by researchers in carrying out enzymatic detoxification. In addition, the application of enzymatic detoxification in food and feed is discussed and future directions for the development of enzymatic detoxification methods are proposed for future in-depth study of enzymatic detoxification methods.

Spirobenzofuran Mitigates Ochratoxin A-Mediated Intestinal Adverse Effects in Pigs through Regulation of Beta Defensin 1

Antimicrobial peptides (AMPs) function to extensively suppress various problematic factors and are considered a new alternative for improving livestock health and enhancing immunomodulation. In this study, we explored whether AMP regulation has positive influences on Ochratoxin A (OTA) exposure using a porcine intestinal epithelial cell line (IPEC-J2 cells). We constructed a beta-defensin 1 (DEFB1) expression vector and used it to transfection IPEC-J2 cells to construct AMP overexpression cell lines. The results showed that OTA induced cytotoxicity, decreased cell migration, and increased inflammatory markers mRNA in IPEC-J2 cells. In DEFB1 overexpressing cell lines, OTA-induced reduced cell migration and increased inflammatory markers mRNA were alleviated. Additionally, a natural product capable of inducing DEFB1 expression, which was selected through high-throughput screening, showed significant alleviation of cytotoxicity, cell migration, and inflammatory markers compared to OTA-treated IPEC-J2 cells. Our finding provides novel insights and clues for the porcine industry, which is affected by OTA exposure.

Evaluation of Cross-Talk and Alleviate Potential of Cytotoxic Factors Induced by Deoxynivalenol in IPEC-J2 Cells Interference with Curcumin

Deoxynivalenol (DON) is a mycotoxin produced by Fusarium graminearum, and curcumin (CUR) is a natural polyphenolic compound found in turmeric. However, the combined treatment of CUR and DON to explore the mitigating effect of CUR on DON and their combined mechanism of action is not clear. Therefore, in this study, we established four treatment groups (CON, CUR, DON and CUR + DON) to investigate their mechanism in the porcine intestinal epithelial cells (IPEC-J2). In addition, the cross-talk and alleviating potential of CUR interfering with DON-induced cytotoxic factors were evaluated by in vitro experiments; the results showed that CUR could effectively inhibit DON-exposed activated TNF-α/NF-κB pathway, attenuate DON-induced apoptosis, and alleviate DON-induced endoplasmic reticulum stress and oxidative stress through PERK/CHOP pathways, which were verified at both mRNA and protein levels. In conclusion, these promising findings may contribute to the future use of CUR as a novel feed additive to protect livestock from the harmful effects of DON.

Fumonisins alone or mixed with other fusariotoxins increase the C22-24:C16 sphingolipid ratios in chicken livers, while deoxynivalenol and zearalenone have no effect

Poultry feed is often contaminated with fumonisins, deoxynivalenol, and zearalenone, which can result in oxidative damage, inflammation and change in lipid metabolism. Although sphingolipids play key roles in cells, only the effects of fumonisins on the sphingolipidome are well-documented. In chickens, fumonisins have been shown to increase the sphinganine to sphingosine ratio and the C22-24:C16 sphingolipid ratio, which has been proposed as a new biomarker of toxicity. In this study, we used UHPLC-MSMS targeted analysis to measure the effect of fusariotoxins on sphingolipids in the livers of chickens fed with diets containing fusariotoxins administered individually and in combination, at the maximum levels recommended by the European Commission. Chickens were exposed from hatching until they reached 35 days of age. This study revealed for the first time that fumonisins, deoxynivalenol, and zearalenone alone and in combination have numerous effects on the sphingolipidome in chicken livers. A 30-50 % decrease in ceramide, dihydroceramide, sphingomyelin, dihydrosphingomyelin, monohexosylceramide and lactosylceramide measured at the class level was observed when fusariotoxins were administered alone, whereas a 30-100 % increase in dihydroceramide, sphingomyelin, dihydrosphingomyelin, and monohexosylceramide was observed when the fusariotoxins were administered in combination. For these different variables, strong significant interactions were observed between fumonisins and zearalenone and between fumonisins and deoxynivalenol, whereas interactions between deoxynivalenol and zearalenone were less frequent and less significant. Interestingly, an increase in the C22-24:C16 ratio of ceramides, sphingomyelins, and monohexosylceramides was observed in chickens fed the diets containing fumonisins only, and this increase was close when the toxin was administered alone or in combination with deoxynivalenol and zearalenone. This effect mainly corresponded to a decrease in sphingolipids with a fatty acid chain length of 16 carbons, whereas C22-24 sphingolipids were unaffected or increased. In conclusion the C22-24:C16 ratio emerged as a specific biomarker, with variations dependent only on the presence of fumonisins.

Alternariol Monomethyl-Ether Induces Toxicity via Cell Death and Oxidative Stress in Swine Intestinal Epithelial Cells

Alternariol monomethyl-ether (AME), together with altenuene and alternariol, belongs to the Alternaria mycotoxins group, which can contaminate different substrates, including cereals. The aim of the present study was to obtain a deeper understanding concerning the effects of AME on pig intestinal health using epithelial intestinal cell lines as the data concerning the possible effects of Alternaria toxins on swine are scarce and insufficient for assessing the risk represented by Alternaria toxins for animal health. Our results have shown a dose-related effect on IPEC-1 cell viability, with an IC50 value of 10.5 μM. Exposure to the toxin induced an increase in total apoptotic cells, suggesting that AME induces programmed cell death through apoptosis based on caspase-3/7 activation in IPEC-1 cells. DNA and protein oxidative damage triggered by AME were associated with an alteration of the antioxidant response, as shown by a decrease in the enzymatic activity of catalase and superoxide dismutase. These effects on the oxidative response can be related to an inhibition of the Akt/Nrf2/HO-1 signaling pathway; however, further studies are needed in order to validate these in vitro data using in vivo trials in swine.

Astragalus polysaccharide: implication for intestinal barrier, anti-inflammation, and animal production

Intestine is responsible for nutrients absorption and plays a key role in defending against various dietary allergens, antigens, toxins, and pathogens. Accumulating evidence reported a critical role of intestine in maintaining animal and human health. Since the use of antibiotics as growth promoters in animal feed has been restricted in many countries, alternatives to antibiotics have been globally investigated, and polysaccharides are considered as environmentally friendly and promising alternatives to improve intestinal health, which has become a research hotspot due to its antibiotic substitution effect. Astragalus polysaccharide (APS), a biological macromolecule, is extracted from astragalus and has been reported to exhibit complex biological activities involved in intestinal barrier integrity maintenance, intestinal microbiota regulation, short-chain fatty acids (SCFAs) production, and immune response regulation, which are critical for intestine health. The biological activity of APS is related to its chemical structure. In this review, we outlined the source and structure of APS, highlighted recent findings on the regulation of APS on physical barrier, biochemical barrier, immunological barrier, and immune response as well as the latest progress of APS as an antibiotic substitute in animal production. We hope this review could provide scientific basis and new insights for the application of APS in nutrition, clinical medicine and health by understanding particular effects of APS on intestine health, anti-inflammation, and animal production.

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.

Resveratrol Alleviates Zearalenone-Induced Intestinal Dysfunction in Mice through the NF-κB/Nrf2/HO-1 Signalling Pathway

Zearalenone (ZEA), a mycotoxin widely present in crops and food, poses a major threat to animal and human health. The consumption of ZEA-contaminated food or feed causes intestinal damage. Therefore, exploring how to mitigate the intestinal damage caused by its ZEA is becoming increasingly important. Resveratrol (RSV), a polyphenol compound, mainly exists in Vitis vinifera, Polygonum cuspidatum, Arachis hypogaea, and other plants. It has potent anti-inflammatory and antioxidant activity. The primary objective of this study was to assess the defensive effects of RSV and its molecular mechanism on the intestinal mucosal injury induced by ZEA exposure in mice. The results showed that RSV pretreatment significantly reduced serum DAO and that D-lactate levels altered intestinal morphology and markedly restored TJ protein levels, intestinal goblet cell number, and MUC-2 gene expression after ZEA challenge. In addition, RSV significantly reversed serum pro-inflammatory factor levels and abnormal changes in intestinal MDA, CAT, and T-SOD. Additional research demonstrated that RSV decreased inflammation by blocking the translocation of nuclear factor-kappaB (NF-κB) p65 and decreased oxidative stress by activating the nuclear factor E2-related factor 2 (Nrf2) pathway and its associated antioxidant genes, including NQO1, γ-GCS, and GSH-PX. In summary, RSV supplementation attenuates intestinal oxidative stress, inflammation, and intestinal barrier dysfunction induced by ZEA exposure by mediating the NF-κB and Nrf2/HO-1 pathways.

Lycopene as a Therapeutic Agent against Aflatoxin B1-Related Toxicity: Mechanistic Insights and Future Directions

Aflatoxin (AFT) contamination poses a significant global public health and safety concern, prompting widespread apprehension. Of the various AFTs, aflatoxin B1 (AFB1) stands out for its pronounced toxicity and its association with a spectrum of chronic ailments, including cardiovascular disease, neurodegenerative disorders, and cancer. Lycopene, a lipid-soluble natural carotenoid, has emerged as a potential mitigator of the deleterious effects induced by AFB1 exposure, spanning cardiac injury, hepatotoxicity, nephrotoxicity, intestinal damage, and reproductive impairment. This protective mechanism operates by reducing oxidative stress, inflammation, and lipid peroxidation, and activating the mitochondrial apoptotic pathway, facilitating the activation of mitochondrial biogenesis, the endogenous antioxidant system, and the nuclear factor erythroid 2-related factor 2 (Nrf2)/kelch-like ECH-associated protein 1 (KEAP1) and peroxisome proliferator-activated receptor-γ coactivator-1 (PGC-1) pathways, as well as regulating the activities of cytochrome P450 (CYP450) enzymes. This review provides an overview of the protective effects of lycopene against AFB1 exposure-induced toxicity and the underlying molecular mechanisms. Furthermore, it explores the safety profile and potential clinical applications of lycopene. The present review underscores lycopene's potential as a promising detoxification agent against AFB1 exposure, with the intent to stimulate further research and practical utilization in this domain.

Aerial parts of Angelica sinensis supplementation for improved broiler growth and intestinal health

This research examined the impact of incorporating Angelica sinensis's aerial components (APA), commonly referred to as "female ginseng", into broilers' diet. Two hundred eighty-eight 1-day-old Cobb 500 broilers were randomly assigned to the 4 experimental groups with 6 replications and 12 birds/replicate. The 4 groups were fed the diets included 4 concentrations of APA (0, 1, 2, and 3%, respectively). The study spanned 42 d, categorized as the starter phase (1-21 d) and the finisher phase (22-42 d). Notably, broilers fed with 3% APA demonstrated a pronounced surge in feed consumption and weight gain during the 22 to 42 d and over the full 42-d period (P < 0.05). Furthermore, when examining the broilers' intestinal structure, there was a notable increase in the villus height and villi ratio across the duodenum, jejunum, and ileum, with a decrease in crypt depth upon 3% APA inclusion (P < 0.05). On a molecular note, certain genes connected to the intestinal mechanical barrier, such as Zona Occludens 1 and Claudin-2, saw significant elevation in the jejunum (P < 0.05). The jejunum also displayed heightened levels of antimicrobial peptides like lysozyme, mucin 2, sIgA, IgG, and IgM, showcasing an enhanced chemical and immune barrier (P < 0.05). Delving into the 16SrDNA sequencing of intestinal content, a higher microbial diversity was evident with a surge in beneficial bacteria, particularly Firmicutes, advocating a resilient and balanced microecosystem. The findings imply that a 3% APA dietary addition bolsters growth metrics and fortifies the intestinal barrier's structural and functional integrity in broilers.

A high-throughput gut-on-chip platform to study the epithelial responses to enterotoxins

Enterotoxins are a type of toxins that primarily affect the intestines. Understanding their harmful effects is essential for food safety and medical research. Current methods lack high-throughput, robust, and translatable models capable of characterizing toxin-specific epithelial damage. Pressing concerns regarding enterotoxin contamination of foods and emerging interest in clinical applications of enterotoxins emphasize the need for new platforms. Here, we demonstrate how Caco-2 tubules can be used to study the effect of enterotoxins on the human intestinal epithelium, reflecting toxins' distinct pathogenic mechanisms. After exposure of the model to toxins nigericin, ochratoxin A, patulin and melittin, we observed dose-dependent reductions in barrier permeability as measured by TEER, which were detected with higher sensitivity than previous studies using conventional models. Combination of LDH release assays and DRAQ7 staining allowed comprehensive evaluation of toxin cytotoxicity, which was only observed after exposure to melittin and ochratoxin A. Furthermore, the study of actin cytoskeleton allowed to assess toxin-induced changes in cell morphology, which were only caused by nigericin. Altogether, our study highlights the potential of our Caco-2 tubular model in becoming a multi-parametric and high-throughput tool to bridge the gap between current enterotoxin research and translatable in vivo models of the human intestinal epithelium.

Co-exposure ochratoxin A and triadimefon influenced the hepatic glucolipid metabolism and intestinal micro-environment in mice

Ochratoxin A (OTA) is a mycotoxin, and triadimefon (TDF) is a triazole fungicide. These compounds are prevalent in the environment, and their residues have been detected in crops. However, the precise health risks associated with mycotoxins and fungicides are not fully elucidated. In this work, five-week-old mice were gavage with OTA (0.3 and 1.5 mg/kg/day), TDF (10 and 50 mg/kg/day), and OTA + TDF (0.3 + 10 and 1.5 + 50 mg/kg/day) for 28 days. Exposure to OTA, TDF, and OTA + TDF led to significant alterations in liver total cholesterol (TC), triglyceride (TG), and glucose (GLU) levels, as well as in genes associated with glycolipid metabolism in mice. Reduced acylcarnitine levels in serum indicated that OTA, TDF, and co-exposure inhibited fatty acid (FA) β-oxidation. Furthermore, OTA and TDF disrupted the integrality of the gut barrier function and altered the structure of the intestinal microbiota. These findings suggested that OTA, TDF, and their co-exposure might disrupt the intestinal barrier, alter the structure of the microbiota, and subsequently inhibit FA β-oxidation, indicating the interference of OTA and TDF with glycolipid-related intestinal barrier dysfunction. Moreover, our data revealed a toxic additive effect between OTA and TDF, providing a foundation for assessing the combined toxicity risk of mycotoxins and fungicides.

HLA gene variations and mycotoxin toxicity: Four case reports

Mycotoxins are produced by certain molds that can cause many health effects. We present four human cases of prolonged consistent mycotoxins exposure linked to genetic variations in human leukocyte antigen (HLA) alleles. The HLA-DR/DQ isotype alleles are linked to mycotoxins susceptibility due to the lack of proper immune response; individuals with these alleles are poor eliminators of mycotoxins from their system. Four subjects with variations in their HLA-DR alleles were exposed to mycotoxins from living in mold-infested houses and experienced persistent mold-related symptoms long after moving out from the mold-infested houses and only exposed to the levels of molds found in the ambient air. From one of the subjects, two urine samples were collected ~ 18 months apart after the cessation of exposure. Urinary elimination rate was extremely slow for two of the mycotoxins (ochratoxin A [OTA] and mycophenolic acid [MPA]) detected in both samples. In 18 months, decline in OTA level was only ~ 3-fold (estimated t½ of ~ 311 days) and decline in MPA level was ~ 11-fold (estimated t½ of ~ 160 days), which was ~ 10- and ~ 213-fold slower than expected in individuals without HLA-DR alleles, respectively. We estimated that ~ 4.3 and ~ 2.2 years will be required for OTA and MPA to reach < LLQ in urine, respectively. Three other subjects with variations in HLA-DR alleles were members of a family who lived in a mold-infested house for 4 years. They kept experiencing mold-related issues >2 years after moving to a non-mold-infested house. Consistent exposure was confirmed by the presence of several mycotoxins in urine >2 years after the secession of higher than background (from outdoor ambient air) exposure. This was consistent with the extremely slow elimination of mycotoxins from their system. Variations in HLA-DR alleles can, consequently, make even short periods of exposure to chronic exposure scenarios with related adverse health effects. It is, therefore, important to determine genetic predisposition as a reason for prolonged/lingering mold-related symptoms long after the cessation of higher than background exposure. Increased human exposure to mycotoxins is expected from increased mold infestation that is anticipated due to rising CO2, temperature, and humidity from the climate change with possibly increased adverse health effects, especially in individuals with genetic susceptibility to mold toxicity.

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.

Dietary restriction rescues 5-fluorouracil-induced lethal intestinal toxicity in old mice by blocking translocation of opportunistic pathogens

Chemotherapy remains a major treatment for malignant tumors, yet the application of standard dose intensity chemotherapy is limited due to the side effects of cytotoxic drugs, especially in old populations. The underlying mechanisms of cytotoxicity and strategies to increase the safety and tolerance of chemotherapy remain to be explored. Using 5-fluorouracil (5-FU), a cornerstone chemotherapeutic drug, we demonstrate that the main cause of death in ad libitum (AL) fed mice after 5-FU chemotherapy was infection caused by translocation of intestinal opportunistic pathogens. We show that these opportunistic pathogens greatly increase in the intestine after chemotherapy, which was closely related to loss of intestinal lysozyme. Of note, two weeks of dietary restriction (DR) prior to chemotherapy significantly protected the loss of lysozyme and increased the content of the beneficial Lactobacillus genera, resulting in a substantial inhibition of intestinal opportunistic pathogens and their translocation. The rescue effect of DR could be mimicked by Lysozyme or Lactobacillus gavage. Our study provides the first evidence that DR achieved a comprehensive protection of the intestinal physical, biological and chemical barriers, which significantly improved the overall survival of 5-FU-treated mice. Importantly, the above findings were more prominent in old mice. Furthermore, we show that patients over 65 years old have enriched opportunistic pathogens in their gut microbiota, especially after 5-FU based chemotherapy. Our study reveals important mechanisms for the poor chemotherapy tolerance of the elderly population, which can be significantly improved by short-term DR. This study generates new insights into methods for improving the chemotherapeutic prognosis by increasing the chemotherapy tolerance and safety of patients with malignant tumors.

16S rRNA and transcriptome analysis of the FOS-mediated alleviation of Aeromonas hydrophila-induced intestinal damage in Megalobrama amblycephala

This study was conducted to elucidate the effects of FOS that alleviate Aeromonas hydrophila-induced intestinal damage. The results showed that A. hydrophila disrupted the intestinal structure and increased intestinal permeability, causing abnormalities in mucosal pathology. Additionally, A. hydrophila induced an imbalance in the intestinal flora and disturbed its stability. Dietary FOS ameliorated the injury to the intestinal structure of fish, but also in part improved the condition of the intestinal tight junction complex. Transcriptomic analysis showed that 120 genes were up-regulated and 320 genes were down-regulated. The intestinal immune network for the IgA production signalling pathway was enriched following A. hydrophila infection, and the change in the FOS group was mainly in the Tight junction signalling pathway. Similarly, dietary FOS reduced the disruption of the intestinal microbiota induced by A. hydrophila and improved the intestinal microbiota's stability; FOS was also partially implicated in the upregulation of Tight junction and Adhesion junction pathways by transcriptomic analysis. After further analysis, it was found that fish fed FOS had upregulated expression of genes related to apoptosis, antigen presentation, and the T-cell-mediated immune response in the intestine compared with those in the A. hydrophila group, which may be related to changes in the intestinal microbiome.

Aflatoxin M1 decreases the expression of genes encoding tight junction proteins and influences the intestinal epithelial integrity

Aflatoxin M1 (AFM1) is a mycotoxin that is commonly found as a milk contaminant, and its presence in milk has been linked to cytotoxicity. The present study aimed to evaluate the acute cytotoxic effects of AFM1 on intestinal Caco-2 cells. Initially, we checked the morphology and viability of Caco-2 cells after treatment with different concentrations of AFM1 (5 ng/L, 50 ng/L, 250 ng/L, 500 ng/L, 1000 ng/L, and 2000 ng/L) for different time intervals (6 h, 12 h, and 24 h). It was found that AFM1 did not show any effect on cell morphology, but 10% decrease in viability above 1000 ng/L after 12 h. Furthermore, DCFDA assay showed increased ROS production after 6 h treatments. qPCR analysis showed an increased expression of epithelial-specific cytoskeleton marker genes, Cytokeratin, Villin, Vimentin, and JAM-1, and a decreased expression of tight junction protein genes, Claudin-1, Occludin, and ZO-1. Similarly, we found an increased expression of Cyp1a1 transcript with an increasing AFM1 concentration and incubation time. This gene expression analysis showed AFM1 can cause disruption of tight junctions between intestinal cells, which was further confirmed by a transwell experiment. In conclusion, consumption of AFM1-contaminated milk does not show any effect on cells morphology and viability but decreases the expression of intestinal barrier transcripts that may lead to the disruption of intestinal barrier function and leaky gut.

Immunomodulatory Effects of Microcin C7 in Cyclophosphamide-Induced Immunosuppressed Mice

Microcin C7 (McC) as a viable immunomodulator peptide can be a potential solution for pathogenic microbial infection in the post-antibiotic era and has gained substantial attention. This study was designed to evaluate the immunomodulatory activity of Microcin C7 in a cyclophosphamide (CTX)-induced immunodeficient mouse model. We show that Microcin C7 treatment significantly alleviated the CTX-caused body weight loss, improved the feed and water consumption to improve the state of the mice, and elevated the absolute number and proportion of peripheral blood lymphocytes as well as the level of hemoglobulin. We further aim to characterize the phenotypes of the immune function and intestinal health profiles. The results demonstrate that Microcin C7 treatment increased serum levels of immunoglobulin A (IgA), IgG, interleukin 6, and hemolysin, promoted splenic lymphocyte proliferation induced by concanavalin A and LPS, and enhanced the phagocytosis of peritoneal macrophages immunized by sheep red blood cells. Additionally, Microcin C7 treatment decreased levels of diamine oxidase and d-lactate, ameliorated CTX-induced intestinal morphological damage, and increased the levels of zonula occluden 1, occludin, claudin-1, mucin 2, and secretary IgA in the jejunum and colon. Moreover, Microcin C7 administration is sufficient to reverse CTX-induced intestinal microbiota dysbiosis by increasing the number of Lactobacillus and Bifidobacterium, decreasing the number of Escherichia coli in colonic contents. Collectively, our results demonstrate that Microcin C7 may have protective and immunomodulatory functions and could be a potential candidate used in animal feed, functional foods, and immunological regimens..

Porcine β-defensin-2 alleviates AFB1-induced intestinal mucosal injury by inhibiting oxidative stress and apoptosis

Aflatoxin B1 (AFB1) is the most toxic mycotoxin contaminant, which is widely present in crops and poses a major safety hazard to animal and human health. To alleviate the cytotoxic effects of AFB1 on the intestine, we tested the protective effects of porcine β-defensin-2 (pBD-2). Results demonstrated that pBD-2 inhibited oxidative stress induced by AFB1 via decreasing the levels of ROS and enhancing the expression of antioxidant factors SOD-2 and NQO-1. In addition, pBD-2 attenuated AFB1-induced intestinal porcine epithelial cell line-J2 (IPEC-J2) injury through blocking mitochondria-mediated apoptosis. In vivo, pBD-2 treatment restored the intestinal mucosal structure and reduced the expression levels of apoptosis factors caspase-3 and Bax/Bcl-2. In conclusion, these results indicated that pBD-2 can alleviate AFB1-induced intestinal mucosal injury by inhibiting oxidative stress and mitochondria-mediated apoptosis. This study provides an effective strategy in developing pBD-2 as green feed additive to prevent AFB1 damage to animals.

Zearalenone Exposure Disrupts STAT-ISG15 in Rat Colon: A Potential Linkage between Zearalenone and Inflammatory Bowel Disease

Zearalenone (ZEN), a prevalent mycotoxin contaminating food and known for its intestinal toxicity, has been suggested as a potential risk factor for inflammatory bowel disease (IBD), although the exact relationship between ZEN exposure and IBD remains unclear. In this study, we established a rat model of colon toxicity induced by ZEN exposure to investigate the key targets of ZEN-induced colon toxicity and explore the underlying connection between ZEN exposure and IBD. Histological staining of the rat colon revealed significant pathological changes resulting from ZEN exposure (p < 0.01). Furthermore, the proteomic analysis demonstrated a notable upregulation of protein expression levels, specifically STAT2 (0.12 ± 0.0186), STAT6 (0.36 ± 0.0475) and ISG15 (0.43 ± 0.0226) in the rat colon (p < 0.05). Utilizing bioinformatics analysis, we combined ZEN exposure and IBD clinical sample databases to reveal that ZEN exposure may increase the risk of IBD through activation of the STAT-ISG15 pathway. This study identified novel targets for ZEN-induced intestinal toxicity, providing the basis for further study of ZEN exposure to IBD.

TLR/MyD88-Mediated Inflammation Induced in Porcine Intestinal Epithelial Cells by Ochratoxin A Affects Intestinal Barrier Function

The intestinal epithelium performs vital functions such as nutrient absorption and acting as an intestinal barrier to maintain the host's homeostasis. Mycotoxin, which affects the processing and storage of animal feedstuff, is a problematic pollutant in farming products. Ochratoxin A generated by Aspergillus and Penicillium fungi causes inflammation, intestinal dysfunction, decline in growth, and reduced intake in porcine and other livestock. Despite these ongoing problems, OTA-related studies in intestinal epithelium are lacking. This study aimed to demonstrate that OTA regulates TLR/MyD88 signaling in IPEC-J2 cells and induces barrier function impairment through tight junction reduction. We measured expression of TLR/MyD88 signaling-related mRNAs and proteins. The indicator of intestinal barrier integrity was confirmed through immunofluorescence and transepithelial electrical resistance. Additionally, we confirmed whether inflammatory cytokines and barrier function were affected by MyD88 inhibition. MyD88 inhibition alleviated inflammatory cytokine levels, tight junction reduction, and damage to barrier function due to OTA. These results indicate that OTA induces TLR/MyD88 signaling-related genes and impairs tight junctions and intestinal barrier function in IPEC-J2 cells. MyD88 regulation in OTA-treated IPEC-J2 cells mitigates the tight junction and intestinal barrier function impairments. Our findings provide a molecular understanding of OTA toxicity in porcine intestinal epithelial cells.

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.

Cordyceps militaris polysaccharide alleviates diabetic symptoms by regulating gut microbiota against TLR4/NF-κB pathway

The relationship between gut microbiota and type 2 diabetes mellitus (T2DM) has attracted increasing attention. In our work, one purified fraction a (AEPSa) was obtained from Cordyceps militaris polysaccharides, and its hypoglycemic activity and underlying mechanisms were investigated in high-fat diet (HFD)- and streptozotocin (STZ)-induced T2DM mice. The results revealed that AEPSa reshaped gut microbiota by increasing Allobaculum, Alistipes, Lachnospiraceae_NK4A136_group and norank_f_Muribaculaceae and decreasing Enterococcus and Ruminococcus_torques_group to inhibit the colonic toll-like receptor 4 (TLR4)/nuclear factor kappa-B (NF-κB) pathway and upregulate intestinal tight junction protein expression, thereby improving glucose and serum lipid metabolism, hormone secretion and complications. Fecal microbiota transplantation (FMT) also confirmed these findings. These results indicated that symptomatic relief of T2DM might be related to AEPSa regulating the gut microbiota against the TLR4/NF-κB pathway to protect the intestinal barrier. Therefore, AEPSa might be developed as a prebiotic agent against T2DM by regulating gut microbiota.

Chronic exposure to zearalenone induces intestinal inflammation and oxidative injury in adult Drosophila melanogaster midgut

In the past decade, mycotoxin zearalenone (ZEN)-induced gastrointestinal adverse effects have been increasingly attracting worldwide attention. This study aimed to determine the gastrointestinal adverse effects of ZEN in Drosophila melanogaster (D. melanogaster) and reveal possible mechanisms of action of ZEN in insects. Here, chronic exposure of D. melanogaster to ZEN killed flies in a dose-dependent manner (2-20 µM). ZEN (20 µM) decreased the survival rates and climbing ability of flies, and activated immune deficiency-mediated intestinal immunity in midgut, leading to the production of antimicrobial peptides. Meanwhile, ZEN exposure induced morphological alteration of adult midgut. Further study suggested that high levels of oxidative stress was observed in ZEN-treated midgut due to the imbalance between the production of reactive oxygen species and the expression and activities of cellular antioxidant enzyme, including superoxide dismutase and catalase. ZEN-induced oxidative stress then caused cell death, impaired gut barrier function and increased gut permeability, leading to oxidative injury in midgut. Subsequently, ZEN-induce midgut injury further disrupted intestinal stem cell (ISC) homeostasis, stimulating ISC proliferation and tissue regeneration, but did not alter cell fate specification of ISC. Additionally, activation of Jun N-terminal kinase pathway was involved in ZEN-induced oxidative injury and tissue regeneration in midgut. Antioxidant vitamin E alleviated ZEN-induced oxidative injury to midgut epithelium. Collectively, this study provided additional evidences for ZEN-induced gastrointestinal adverse effects from an invertebrate model, extended our understanding of the mechanisms mediating mycotoxin toxicity in organisms.

Occurrence and Dietary Exposure Assessment to Enniatin B through Consumption of Cereal-Based Products in Spain and the Catalonia Region

Enniatin B (ENNB) is a mycotoxin produced by moulds from the Fusarium genera and its toxic effects are still not fully elucidated, hence a safe reference exposure value has not been established yet. ENNB is the most prevalent emerging mycotoxin and is widely found in cereal-based products, nevertheless, there are no comprehensive exposure assessment studies. For that reason, the aim of this study was to characterise the occurrence of ENNB and estimate the exposure of the Spanish and Catalan populations. A total of 347 cereal-based products were collected in 2019 and were analysed using liquid chromatography-tandem mass spectrometry. Consumption data were obtained from the national food consumption surveys (ENALIA) and a regional survey conducted in Catalonia. The global exposure was estimated using deterministic and probabilistic methods. The results showed a high occurrence of close to 100% in all foodstuffs, with a range from 6 to 269 µg/kg, and a strong correlation with the levels of deoxynivalenol. Children aged one-nine years were the most exposed, showing mean estimates in the range 308-324 ng/kg bw/day and 95th percentiles 697-781 ng/kg bw/day. This study stresses the need for further toxicological data to establish reference doses and conclude formal risk assessment, accounting for the co-occurrence with deoxynivalenol.

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

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.

Constitutively active microglial populations limit anorexia induced by the food contaminant deoxynivalenol

Microglia are involved in neuroinflammatory processes during diverse pathophysiological conditions. To date, the possible contribution of these cells to deoxynivalenol (DON)-induced brain inflammation and anorexia has not yet been evaluated. DON, one of the most abundant trichothecenes found in cereals, has been implicated in mycotoxicosis in both humans and farm animals. DON-induced toxicity is characterized by reduced food intake, weight gain, and immunological effects. We previously showed that exposure to DON induces an inflammatory response within the hypothalamus and dorsal vagal complex (DVC) which contributes to DON-induced anorexia. Here, in response to anorectic DON doses, we reported microglial activation within two circumventricular organs (CVOs), the area postrema (AP) and median eminence (ME) located in the DVC and the hypothalamus, respectively. Interestingly, this microglial activation was observed while DON-induced anorexia was ongoing (i.e., 3 and 6 h after DON administration). Next, we took advantage of pharmacological microglia deletion using PLX3397, a colony-stimulating factor 1 receptor (CSF1R)-inhibitor. Surprisingly, microglia-depleted mice exhibited an increased sensitivity to DON since non-anorectic DON doses reduced food intake in PLX3397-treated mice. Moreover, low DON doses induced c-Fos expression within feeding behavior-associated structures in PLX3397-treated mice but not in control mice. In parallel, we have highlighted heterogeneity in the phenotype of microglial cells present in and around the AP and ME of control animals. In these areas, microglial subpopulations expressed IBA1, TMEM119, CD11b and CD68 to varying degrees. In addition, a CD68 positive subpopulation showed, under resting conditions, a noticeable phagocytotic/endocytotic activity. We observed that DON strongly reduced CD68 in the hypothalamus and DVC. Finally, inactivation of constitutively active microglia by intraperitoneal administration of minocycline resulted in anorexia with a DON dose ineffective in control mice. Taken together, these results strongly suggest that various populations of microglial cells residing in and around the CVOs are maintained in a functionally active state even under physiological conditions. We propose that these microglial cell populations are attempting to protect the brain parenchyma from hazardous molecules coming from the blood. This study could contribute to a better understanding of how microglia respond to environmental contaminants.

Feed Safety and the Development of Poultry Intestinal Microbiota

Simple Summary

Intensive gut colonisation of animals starts immediately after birth or hatch. Oral route of colonisation, and consequently the first feed, plays a significant role in the continual defining of the intestinal microbial community. The feed can influence colonisation in two ways: providing the microbial inoculum and providing the nutritional requirements that suit a specific type of microbes. In combination with environmental factors, feed shapes animal’s future health and performance from the first day of life. The objective of this review was to investigate feed safety aspects of animal nutrition from the gut colonisation aspect.

Abstract

The first feed offered to young chicks is likely the most important meal in their life. The complex gut colonisation process is determined with early exposure and during the first days of life before the microbial community is formed. Therefore, providing access to high-quality feed and an environment enriched in the beneficial and deprived of pathogenic microorganisms during this period is critical. Feed often carries a complex microbial community that can contain major poultry pathogens and a range of chemical contaminants such as heavy metals, mycotoxins, pesticides and herbicides, which, although present in minute amounts, can have a profound effect on the development of the microbial community and have a permanent effect on bird’s overall health and performance. The magnitude of their interference with gut colonisation in livestock is yet to be determined. Here, we present the animal feed quality issues that can significantly influence the microbial community development, thus severely affecting the bird’s health and performance.

Luteolin and Chrysin Could Prevent E. coli Lipopolysaccharide-Ochratoxin A Combination-Caused Inflammation and Oxidative Stress in In Vitro Porcine Intestinal Model

Ochratoxin A (OTA) and lipopolysaccharide (LPS) intake can cause gastrointestinal disorders. Polyphenolic chrysin (CHR) and luteolin (LUT) display anti-inflammatory and antioxidant properties. Porcine intestinal epithelial (jejunal) IPEC-J2 cells were treated with OTA (1 µM, 5 µM and 20 µM), E. coli LPS (10 µg/mL), CHR (1 µM) and LUT (8.7 µM) alone and in their combinations. Cell viabilities (MTS assay) and extracellular (EC) hydrogen-peroxide (H2O2) production (Amplex red method) were evaluated. Intracellular (IC) reactive oxygen species (ROS) were assessed using a 2′-7′dichlorodihydrofluorescein diacetate (DCFH-DA) procedure. ELISA assay was used to evaluate IL-6 and IL-8 secretion. OTA decreased cell viabilities (p < 0.001) which could not be alleviated by LUT or CHR (p > 0.05); however, EC H2O2 production was successfully suppressed by LUT in IPEC-J2 cells (p < 0.001). OTA with LPS elevated the IC ROS which was counteracted by CHR and LUT (p < 0.001). IL-6 and IL-8 secretion was elevated by LPS + OTA (p < 0.001) which could be inhibited by LUT (p < 0.01 for IL-6; p < 0.001 for IL-8). Based on our results, CHR and LUT exerted beneficial effects on IC ROS levels and on cytokine secretion (LUT) in vitro; thus, they might be used as dietary and feed supplements to avoid OTA- and LPS-related health risks.

Modulating Activity Evaluation of Gut Microbiota with Versatile Toluquinol

Gut microbiota have important implications for health by affecting the metabolism of diet and drugs. However, the specific microbial mediators and their mechanisms in modulating specific key intermediate metabolites from fungal origins still remain largely unclear. Toluquinol, as a key versatile precursor metabolite, is commonly distributed in many fungi, including Penicillium species and their strains for food production. The common 17 gut microbes were cultivated and fed with and without toluquinol. Metabolic analysis revealed that four strains, including the predominant Enterococcus species, could metabolize toluquinol and produce different metabolites. Chemical investigation on large-scale cultures led to isolation of four targeted metabolites and their structures were characterized with NMR, MS, and X-ray diffraction analysis, as four toluquinol derivatives (1–4) through O1/O4-acetyl and C5/C6-methylsulfonyl substitutions, respectively. The four metabolites were first synthesized in living organisms. Further experiments suggested that the rare methylsulfonyl groups in 3–4 were donated from solvent DMSO through Fenton’s reaction. Metabolite 1 displayed the strongest inhibitory effect on cancer cells A549, A2780, and G401 with IC₅₀ values at 0.224, 0.204, and 0.597 μM, respectively, while metabolite 3 displayed no effect. Our results suggest that the dominant Enterococcus species could modulate potential precursors of fungal origin and change their biological activity.

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.

Adverse Effects of Fusarium Toxins in Ruminants: A Review of In Vivo and In Vitro Studies

With an increased knowledge of the mechanism of action of Fusarium mycotoxins, the concept that these substances are deleterious only for monogastric species is obsolete. Indeed, most mycotoxins can be converted into less toxic compounds by the rumen microflora from healthy animals. However, mycotoxin absorption and its conversion to more toxic metabolites, as well as their impact on the immune response and subsequently animal welfare, reproductive function, and milk quality during chronic exposure should not be neglected. Among the Fusarium mycotoxins, the most studied are deoxynivalenol (DON), zearalenone (ZEN), and fumonisins from the B class (FBs). It is remarkable that there is a paucity of in vivo research, with a low number of studies on nutrient digestibility and rumen function. Most of the in vitro studies are related to the reproductive function or are restricted to rumen incubation. When evaluating the production performance, milk yield is used as an evaluated parameter, but its quality for cheese production is often overlooked. In the present review, we summarize the most recent findings regarding the adverse effects of these mycotoxins with special attention to dairy cattle.

Fumonisin B1 induced intestinal epithelial barrier damage through endoplasmic reticulum stress triggered by the ceramide synthase 2 depletion

Fumonisin B₁ (FB₁) contamination in feed is of great concern nowadays. The intestine would be the first line when FB₁-contaminated food or feed was ingested. However, the intestinal toxicity and mechanism of FB₁ have rarely been studied. In this study, we found that FB₁ inhibited cell viability, and promoted the severe release of lactate dehydrogenase. Meantime, FB₁ destroyed the intestinal physical barrier by reducing the expressions of tight junctions. And FB₁ induced excessive production of cytokines like tumor necrosis factor-α, resulting in damage to the intestinal immunological barrier. Furthermore, we observed that FB₁ preferentially inhibited the expressions of ceramide synthase 2 (CerS2) and upregulated the expression of endoplasmic reticulum (ER) stress markers. The siRNA-mediated knockdown of CerS2 and CerS2 overexpression proved that CerS2 depletion induced by FB₁ triggered ER stress, which then destructed the intestinal barrier. FB₁-induced intestinal impairment could be restored by CerS2 over-expression or 4-Phenylbutyric acid (ER stress inhibitor). Overall, our findings demonstrated intestinal toxicity and potential mechanism of FB₁, and the intestinal impairment risk posed by FB₁ must be taken seriously.

Does Bentonite Cause Cytotoxic and Whole-Transcriptomic Adverse Effects in Enterocytes When Used to Reduce Aflatoxin B1 Exposure?

Aflatoxin B1 (AFB1) is a major food safety concern, threatening the health of humans and animals. Bentonite (BEN) is an aluminosilicate clay used as a feed additive to reduce AFB1 presence in contaminated feedstuff. So far, few studies have characterized BEN toxicity and efficacy in vitro. In this study, cytotoxicity (WST-1 test), the effects on cell permeability (trans-epithelial electrical resistance and lucifer yellow dye incorporation), and transcriptional changes (RNA-seq) caused by BEN, AFB1 and their combination (AFB1 + BEN) were investigated in Caco-2 cells. Up to 0.1 mg/mL, BEN did not affect cell viability and permeability, but it reduced AFB1 cytotoxicity; however, at higher concentrations, BEN was cytotoxic. As to RNA-seq, 0.1 mg/mL BEN did not show effects on cell transcriptome, confirming that the interaction between BEN and AFB1 occurs in the medium. Data from AFB1 and AFB1 + BEN suggested AFB1 provoked most of the transcriptional changes, whereas BEN was preventive. The most interesting AFB1-targeted pathways for which BEN was effective were cell integrity, xenobiotic metabolism and transporters, basal metabolism, inflammation and immune response, p53 biological network, apoptosis and carcinogenesis. To our knowledge, this is the first study assessing the in vitro toxicity and whole-transcriptomic effects of BEN, alone or in the presence of AFB1.

Combinatory Exposure to Urolithin A, Alternariol, and Deoxynivalenol Affects Colon Cancer Metabolism and Epithelial Barrier Integrity in vitro

The human gastrointestinal tract is an important site of nutrient absorption and a crucial barrier against xenobiotics. It regularly faces “chemical cocktails” composed of food constituents, their human and microbial metabolites, and foodborne contaminants, such as mycotoxins. Hence, the colonic epithelium adapts to dietary molecules tuning its immune response, structural integrity, and metabolism to maintain intestinal homeostasis. While gut microbiota metabolites of berry ellagitannins, such as urolithin A (Uro A) might contribute to physiological epithelial barrier integrity, foodborne co-contaminating mycotoxins like alternariol (AOH) and deoxynivalenol (DON) could hamper epithelial function. Hence, we investigated the response of differentiated Caco-2 cells (clone C2BBe1) in vitro to the three compounds alone or in binary mixtures. In virtue of the possible interactions of Uro A, AOH, and DON with the aryl hydrocarbon receptor (AhR) pathway, potential effects on phase-I-metabolism enzymes and epithelial structural integrity were taken as endpoints for the evaluation. Finally, Liquid chromatography tandem mass spectrometry measurements elucidated the absorption, secretion, and metabolic capacity of the cells under single and combinatory exposure scenarios. Uro A and AOH as single compounds, and as a binary mixture, were capable to induce CYP1A1/1A2/1B1 enzymes triggered by the AhR pathway. In light of its ribosome inhibiting capacity, the trichothecene suppressed the effects of both dibenzo-α-pyrones. In turn, cellular responsiveness to Uro A and AOH could be sustained when co-exposed to DON-3-sulfate, instead of DON. Colonic epithelial structural integrity was rather maintained after incubation with Uro A and AOH: this was reinforced in the combinatory exposure scenario and disrupted by DON, an effect, opposed in combination. Passage through the cells as well as the metabolism of Uro A and AOH were rather influenced by co-exposure to DON, than by interaction with each other. Therefore, we conclude that although single foodborne bioactive substances individually could either support or disrupt the epithelial structure and metabolic capacity of colon cancer, exposure to chemical mixtures changes the experimental outcome and calls for the need of combinatory investigations for proper risk assessment.

A polysaccharide from Inonotus obliquus ameliorates intestinal barrier dysfunction in mice with type 2 diabetes mellitus

Type 2 diabetes mellitus is a global disease that endangers human health, and the need for the development of nontoxic treatment candidates is urgent. In the present work, one homogeneous polysaccharide from Inonotus obliquus (IN) was isolated, and the protective effect and mechanism of IN on type 2 diabetes mellitus were investigated from the aspects of the intestinal barrier. IN mainly consisted of 9 monosaccharides with a Mw of 373 kDa. IN attenuated body weight loss, alleviated pathological damage, and suppressed the production of proinflammatory cytokines. Additionally, IN repaired the intestinal barrier by upregulating the expression of Ki-67, ZO-1 and MUC2. Furthermore, the abundance of Firmicutes was significantly increased with IN treatment, while the levels of Bacteroidetes were significantly inhibited. In conclusion, IN protected against type 2 diabetes mellitus by ameliorating intestinal barrier dysfunction and might serve as a novel drug candidate for type 2 diabetes mellitus.

Multi-Omics Reveal Additive Cytotoxicity Effects of Aflatoxin B1 and Aflatoxin M1 toward Intestinal NCM460 Cells

Aflatoxin B1 (AFB1) is a common crop contaminant, while aflatoxin M1 (AFM1) is implicated in milk safety. Humans are likely to be simultaneously exposed to AFB1 and AFM1; however, studies on the combined interactive effects of AFB1 and AFM1 are lacking. To fill this knowledge gap, transcriptomic, proteomic, and microRNA (miRNA)-sequencing approaches were used to investigate the toxic mechanisms underpinning combined AFB1 and AFM1 actions in vitro. Exposure to AFB1 (1.25–20 μM) and AFM1 (5–20 μM) for 48 h significantly decreased cell viability in the intestinal cell line, NCM460. Multi-omics analyses demonstrated that additive toxic effects were induced by combined AFB1 (2.5 μM) and AFM1 (2.5 μM) in NCM460 cells and were associated with p53 signaling pathway, a common pathway enriched by differentially expressed mRNAs/proteins/miRNAs. Specifically, based on p53 signaling, cross-omics showed that AFB1 and AFM1 reduced NCM460 cell viability via the hsa-miR-628-3p- and hsa-miR-217-5p-mediated regulation of cell surface death receptor (FAS), and also the hsa-miR-11-y-mediated regulation of cyclin dependent kinase 2 (CDK2). We provide new insights on biomarkers which reflect the cytotoxic effects of combined AFB1 and AFM1 toxicity.