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

Expression of endogenous UDP-glucosyltransferase in endophyte Phomopsis liquidambaris reduces deoxynivalenol contamination in wheat

Fusarium head blight is a devastating disease that causes severe yield loses and mycotoxin contamination in wheat grain. Additionally, balancing the trade-off between wheat production and disease resistance has proved challenging. This study aimed to expand the genetic tools of the endophyte Phomopsis liquidambaris against Fusarium graminearum. Specifically, we engineered a UDP-glucosyltransferase-expressing P. liquidambaris strain (PL-UGT) using ADE1 as a selection marker and obtained a deletion mutant using an inducible promoter that drives Cas9 expression. Our PL-UGT strain converted deoxynivalenol (DON) into DON-3-G in vitro at a rate of 71.4 % after 36 h. DON inactivation can be used to confer tolerance in planta. Wheat seedlings inoculated with endophytic strain PL-UGT showed improved growth compared with those inoculated with wildtype P. liquidambaris. Strain PL-UGT inhibited the growth of Fusarium graminearum and reduced infection rate to 15.7 %. Consistent with this finding, DON levels in wheat grains decreased from 14.25 to 0.56 μg/g when the flowers were pre-inoculated with PL-UGT and then infected with F. graminearum. The expression of UGT in P. liquidambaris was nontoxic and did not inhibit plant growth. Endophytes do not enter the seeds nor induce plant disease, thereby representing a novel approach to fungal disease control.

Disruption of intestinal epithelial permeability in the Co-culture system of Caco-2/HT29-MTX cells exposed individually or simultaneously to acrylamide and ochratoxin A

Mycotoxins and thermal processing hazards are common contaminants in various foods and cause severe problems in terms of food safety and health. Combined use of acrylamide (AA) and ochratoxin A (OTA) would result in more significant intestinal toxicity than either toxin alone, but the underlying mechanisms behind this poor outcome remain unclear. Herein, we established the co-culture system of Caco-2/HT29-MTX cells for simulating a real intestinal environment that is more sensitive to AA and OTA, and showed that the combination of AA and OTA could up-regulate permeability of the intestine via increasing LY permeabilization, and decreasing TEER, then induce oxidative stress imbalance (GSH, SOD, MDA, and ROS) and inflammatory system disorder (TNF-α, IL-1β, IL-10, and IL-6), thereby leading a rapid decline in cell viability. Western blot, PAS- and AB-staining revealed that AA and OTA showed a synergistic effect on the intestine mainly through the disruption of tight junctions (TJs) and a mucus layer. Furthermore, based on correlation analysis, oxidative stress was more relevant to the mucus layer and TJs. Therefore, our findings provide a better evaluation model and a potential mechanism for further determining or preventing the combined toxicity caused by AA and OTA.

Recalling the reported toxicity assessment of deoxynivalenol, mitigating strategies and its toxicity mechanisms: Comprehensive review

Mycotoxins frequently contaminate a variety of food items, posing significant concerns for both food safety and public health. The adverse consequences linked to poisoning from these substances encompass symptoms such as vomiting, loss of appetite, diarrhea, the potential for cancer development, impairments to the immune system, disruptions in neuroendocrine function, genetic damage, and, in severe cases, fatality. The deoxynivalenol (DON) raises significant concerns for both food safety and human health, particularly due to its potential harm to vital organs in the body. It is one of the most prevalent fungal contaminants found in edible items used by humans and animals globally. The presence of harmful mycotoxins, including DON, in food has caused widespread worry. Altered versions of DON have arisen as possible risks to the environment and well-being, as they exhibit a greater propensity to revert back to the original mycotoxins. This can result in the buildup of mycotoxins in both animals and humans, underscoring the pressing requirement for additional investigation into the adverse consequences of these modified mycotoxins. Furthermore, due to the lack of sufficient safety data, accurately evaluating the risk posed by modified mycotoxins remains challenging. Our review study delves into conjugated forms of DON, exploring its structure, toxicity, control strategies, and a novel animal model for assessing its toxicity. Various toxicities, such as acute, sub-acute, chronic, and cellular, are proposed as potential mechanisms contributing to the toxicity of conjugated forms of DON. Additionally, the study offers an overview of DON's toxicity mechanisms and discusses its widespread presence worldwide. A thorough exploration of the health risk evaluation associated with conjugated form of DON is also provided in this discussion.

Arsenic Exposure-Induced Acute Kidney Injury by Regulating SIRT1/PINK1/Mitophagy Axis in Mice and in HK-2 Cells

Groundwater resources are often contaminated by arsenic, which poses a serious threat to human and animal's health. Some studies have demonstrated that acute arsenic exposure could induce kidney injury because the kidney is a key target organ for toxicity, but the exact mechanism remains unclear. Hence, we investigated the effect of SIRT1-/PINK1-mediated mitophagy on NaAsO2-induced kidney injury in vivo and in vitro. In our study, NaAsO2 exposure obviously induced renal tubule injury and mitochondrial dysfunction. Meanwhile, NaAsO2 exposure could inhibit the mRNA/protein level of SIRT1 and activate the mitophagy-related mRNA/protein levels in the kidney of mice. In HK-2 cells, we also confirmed that NaAsO2-induced nephrotoxicity depended on the activation of mitophagy. Moreover, the activation of SIRT1 by resveratrol alleviated NaAsO2-induced acute kidney injury via the activation of mitophagy in vivo and in vitro. Interestingly, the inhibition of mitophagy by cyclosporin A (CsA) further exacerbated NaAsO2-induced nephrotoxicity and inflammation in HK-2 cells. Taken together, our study found that SIRT1-regulated PINK1-/Parkin-dependent mitophagy was implicated in NaAsO2-induced acute kidney injury. In addition, we confirmed that PINK1-/Parkin-dependent mitophagy played a protective role against NaAsO2-induced acute kidney injury. Therefore, activation of SIRT1 and mitophagy may represent a novel therapeutic target for the prevention and treatment of NaAsO2-induced acute renal injury.

From ribosome to ribotoxins: understanding the toxicity of deoxynivalenol and Shiga toxin, two food borne toxins

Ribosomes that synthesize proteins are among the most central and evolutionarily conserved organelles. Given the key role of proteins in cellular functions, prokaryotic and eukaryotic pathogens have evolved potent toxins to inhibit ribosomal functions and weaken their host. Many of these ribotoxin-producing pathogens are associated with food. For example, food can be contaminated with bacterial pathogens that produce the ribotoxin Shiga toxin, but also with the fungal ribotoxin deoxynivalenol. Shiga toxin cleaves ribosomal RNA, while deoxynivalenol binds to and inhibits the peptidyl transferase center. Despite their distinct modes of action, both groups of ribotoxins hinder protein translation, but also trigger other comparable toxic effects, which depend or not on the activation of the ribotoxic stress response. Ribotoxic stress response-dependent effects include inflammation and apoptosis, whereas ribotoxic stress response-independent effects include endoplasmic reticulum stress, oxidative stress, and autophagy. For other effects, such as cell cycle arrest and cytoskeleton modulation, the involvement of the ribotoxic stress response is still controversial. Ribotoxins affect one organelle yet induce multiple toxic effects with multiple consequences for the cell. The ribosome can therefore be considered as the cellular "Achilles heel" targeted by food borne ribotoxins. Considering the high toxicity of ribotoxins, they pose a substantial health risk, as humans are highly susceptible to widespread exposure to these toxins through contaminated food sources.

3-Acetyldeoxynivalenol induces apoptosis, barrier dysfunction and endoplasmic reticulum stress by inhibiting mTORC1-dependent autophagy in porcine enterocytes

3-Acetyldeoxynivalenol (3-Ac-DON), an acetylated form of deoxynivalenol, is widely present in mycotoxin-contaminated food, feed as well as in other natural sources. Ingestion of 3-Ac-DON may result in intestinal dysfunction, leading to gut diseases in humans and animals. Nevertheless, the molecular mechanism of 3-Ac-DON in intestinal epithelial cytotoxicity remains unclear. In this study, intestinal porcine epithelial cell line 1 (IPEC-1) cells were treated with different concentrations of 3-Ac-DON for 12 h or 24 h, respectively. The results showed that 3-Ac-DON caused decreased cell viability, cell cycle arrest in G1 phase and depolarization of mitochondrial membrane potential. Western blotting analysis showed that 3-Ac-DON significantly decreased the expression of tight junction proteins, inhibited autophagy and activated endoplasmic reticulum (ER) stress in IPEC-1 cells (P < 0.05). Further investigation demonstrated that 3-Ac-DON caused apoptosis, ER stress and barrier dysfunction were reversed after co-treatment with the autophagy activator rapamycin (100 nM), indicating that autophagy plays a key role in the process of 3-Ac-DON-induced cell damage. In addition, we demonstrated that 3-Ac-DON inhibits the occurrence of autophagy mediated by mTORC1 protein. In conclusion, our research indicated that the mTORC1 protein and autophagy played a key role in the 3-Ac-DON-induced cytotoxic in IPEC-1 cells, which would provide new therapeutic targets and ideas for 3-Ac-DON-mediated intestinal injury.

Impact of Enniatin and Deoxynivalenol Co-Occurrence on Plant, Microbial, Insect, Animal and Human Systems: Current Knowledge and Future Perspectives

Fusarium mycotoxins commonly contaminate agricultural products resulting in a serious threat to both animal and human health. The co-occurrence of different mycotoxins in the same cereal field is very common, so the risks as well as the functional and ecological effects of mycotoxins cannot always be predicted by focusing only on the effect of the single contaminants. Enniatins (ENNs) are among the most frequently detected emerging mycotoxins, while deoxynivalenol (DON) is probably the most common contaminant of cereal grains worldwide. The purpose of this review is to provide an overview of the simultaneous exposure to these mycotoxins, with emphasis on the combined effects in multiple organisms. Our literature analysis shows that just a few studies on ENN-DON toxicity are available, suggesting the complexity of mycotoxin interactions, which include synergistic, antagonistic, and additive effects. Both ENNs and DON modulate drug efflux transporters, therefore this specific ability deserves to be explored to better understand their complex biological role. Additionally, future studies should investigate the interaction mechanisms of mycotoxin co-occurrence on different model organisms, using concentrations closer to real exposures.

Deoxynivalenol hijacks the pathway of Janus kinase 2/signal transducers and activators of transcription 3 (JAK2/STAT-3) to drive caspase-3-mediated apoptosis in intestinal porcine epithelial cells

Deoxynivalenol (DON) can easily injure the intestinal tract, which represents the first barrier against food contaminants. The intestinal toxicity induced by DON was mainly focused on mitogen-activated protein kinase (MAPK) activation, however, the underlying mechanisms by which DON triggers apoptosis by other pathways remain poorly understood. In this study, the Janus kinase 2/signal transducers and activators of transcription 3 (JAK2/STAT-3) pathway was proposed to regulate the intrinsic apoptosis induced by DON and thoroughly investigated in intestinal porcine epithelial cells (IPEC-J2). First, DON was found to be able to efficiently inhibit cell viability and increase the release of lactate dehydrogenase. It could also enhance the activity of the cleaved caspase-3 in a time-dependent manner, accompanied by a loss of mitochondrial membrane potential and an up-regulation of the apoptosis rate. Then, the expression of genes associated with inflammation and apoptosis were investigated. DON increased the expression of IL-6, IL-1β, TNF-α, SOCS3 and Bax, but decreased the expression of Bcl-2 and Bcl-xL. Moreover, we discovered that DON robustly inhibited STAT-3 activity together with the down-regulation of JAK2, Bcl-2 and Bcl-xL, paralleling the increase in p38 phosphorylation. Furthermore, a pharmacological activation of JAK2/STAT-3 alleviated DON induced-apoptosis. Concurrent with the apoptotic pathway, during the initial exposure to DON (first 4 h), a survival pathway involving phosphorylated Erk1/2, Akt, and FoxO1 was also observed. Thus, apoptosis induced by DON was Janus faced: although the survival pathway was activated, the DON-induced apoptotic JAK2/STAT-3/caspase-3 pathway dominated, leading to an imbalance in cell homeostasis. This study provides a novel avenue to comprehensively reveal the pathological mechanisms of DON-induced intestinal disorders, which is promising for future applications to other contaminants in food and feed.

The mitigation mechanism of hesperidin on deoxynivalenol toxicity in grass carp hepatocytes via decreasing ROS accumulation and inhibiting JNK phosphorylation

Deoxynivalenol (DON), a crucial kind of mycotoxin, is found globally present in the contaminated cereal crops including wheat, barley, maize and rice. Hesperidin (HDN) is a flavonoid with a variety of biological activities found in high concentrations in citrus fruits. However, the potential protective effects of HDN on cell damage under DON toxicity, and the role of oxidative stress, inflammation, autophagy and apoptosis in it, remain unclear. Therefore, we treated grass carp (Ctenopharyngodon idellus) liver cells (L8824 cell) with DON and HDN for 24 h. The results showed that DON exposure caused a higher ROS accumulation, activated inflammation, autophagy and apoptosis, induced the expression of cytokines (NF-kappaB, TNF-α, IL-1β, IL-6), triggered BCL2/BAX-mediated apoptosis and LC3B/P62-dependent autophagy in the L8824 cell line. Moreover, HDN reduced DON exposure-induced inflammation and autophagy by decreasing ROS accumulation and reduced DON exposure-induced apoptosis by inhibiting JNK phosphorylation. These results partly explained the mechanism of biological threat on fish under DON exposure and the potential application value of HDN in aquaculture.

Lipopolysaccharide aggravates canine influenza a (H3N2) virus infection and lung damage via mTOR/autophagy in vivo and in vitro

Influenza A (H3N2) accounts for the majority of influenza worldwide and continues to challenge human health. Disturbance in the gut microbiota caused by many diseases leads to increased production of lipopolysaccharide (LPS), and LPS induces sepsis and conditions associated with local or systemic inflammation. However, to date, little attention has been paid to the potential impact of LPS on influenza A (H3N2) infection and the potential mechanism. Hence, in this study we used canine influenza A (H3N2) virus (CIV) as a model of influenza A virus to investigate the effect of low-dose of LPS on CIV replication and lung damage and explore the underlying mechanism in mice and A549 and HPAEpiC cells. The results showed that LPS (25 μg/kg) increased CIV infection and lung damage in mice, as indicated by pulmonary virus titer, viral NP levels, lung index, and pulmonary histopathology. LPS (1 μg/ml) also increased CIV replication in A549 cells as indicated by the above same parameters. Furthermore, low doses of LPS reduced CIV-induced p-mTOR protein expression and enhanced CIV-induced autophagy-related mRNA/protein expressions in vivo and in vitro. In addition, the use of the mTOR activator, MHY1485, reversed CIV-induced autophagy and CIV replication in A549 and HPAEpiC cells, respectively. siATG5 alleviated CIV replication exacerbated by LPS in the two lines. In conclusion, LPS aggravates CIV infection and lung damage via mTOR/autophagy.

Isolation, identification and safety evaluation of OTA-detoxification strain Pediococcus acidilactici NJB421 and its effects on OTA-induced toxicity in mice

Ochratoxin A (OTA) is a potent mycotoxin found in foods and feeds, posing a health risk to animals and humans. Biological detoxification of OTA is considered a promising method, and some bacteria and fungi which can degrade OTA are isolated. However, research on safety and alleviating toxic effects are scarce. This study aims to isolate OTA-detoxification probiotics from natural samples and evaluate their safety and protective effects in mice. Here, a new OTA-detoxification strain named Pediococcus acidilactici NJB421 (P. acidilactici NJB421) was isolated from cow manure, which exhibited a removal rate of OTA at 48.53% for 48 h. P. acidilactici NJB421 exhibited high temperature resistance, acid tolerance, 0.3% bile salt and 1.4% trypsin resistance. The safety evaluation showed that P. acidilactici NJB421 at 2 × 10⁸ CFU/per mouse had no abnormalities in body weight, organ indices, ALT, AST and ALP activities, BUN, CRE and TP contents. And P. acidilactici NJB421 alleviated the decreases in body weight, organ indices and small intestinal length, and alleviated intestinal injury, liver injury and kidney injury. These results suggest P. acidilactici NJB421 is safe and has protection against OTA poisoning, which provides a new OTA-detoxification strain for livestock and food industries.

Engineered Phomopsis liquidambaris with Fhb1 and Fhb7 Enhances Resistance to Fusarium graminearum in Wheat

Fusarium head blight is one of the most serious diseases caused by Fusarium graminearum in wheat. Here, we developed a new way to prevent and control Fusarium head blight by introducing the resistance genes Fhb1 and Fhb7 into the endophytic fungus Phomopsis liquidambaris, named PL-Fhb1 and PL-Fhb7, respectively, which could colonize wheat. The wheat seedlings were preinoculated with PL-Fhb1 and PL-Fhb7 to enhance the resistance against deoxynivalenol (DON) and PL-Fhb1 and PL-Fhb7 inhibited the growth of F. graminearum by 73% and 49%, respectively. The incidence rate of diseased spikes decreased to 35.2% and 45.4%, and the corresponding DON levels for wheat grains decreased from 13.2 to 1.79 μg/g and from 13.2 μg/g to 0.39 μg/g when the leaves were preinoculated with PL-Fhb1 and PL-Fhb7 after overwintering, respectively. The incidence rates of diseased spikes decreased to 25.7% and 34.7%, and the DON levels for wheat grains decreased from 17.48 μg/g to 1.23 μg/g and from 17.48 μg/g to 0 μg/g when the wheat flowers were inoculated with PL-Fhb1 and PL-Fhb7, and the wheat flowers were subsequently infected with F. graminearum, respectively. It was confirmed that DON was transformed into DON-glutathione (GSH) by PL-Fhb7 using high-performance liquid chromatography-mass spectrometry (HPLC-MS). However, PL-Fhb1 may have increased plant immunity and enhanced the resistance to F. graminearum. This study indicates that engineered endophytes can improve the resistance to Fusarium head blight and presents a new method for the biological control of Fusarium head blight.

Aflatoxin B1 Induces Intestinal Barrier Dysfunction by Regulating the FXR-Mediated MLCK Signaling Pathway in Mice and in IPEC-J2 Cells

Aflatoxin B1 (AFB1) is a widespread mycotoxin in food and feed. Although the liver is the main target organ of AFB1, the intestine is the first exposure organ to AFB1. However, the mechanism by which AFB1 induced intestinal barrier dysfunction via regulating the farnesoid X receptor (FXR)-mediated myosin light chain kinase (MLCK) signaling pathway has rarely been studied. In vivo, AFB1 exposure significantly decreased the small intestine length and increased the intestinal permeability. Meanwhile, AFB1 exposure markedly suppressed the protein expressions of FXR, ZO-1, occludin, and claudin-1 and enhanced the protein expression of MLCK. In vitro, AFB1 exposure induced intestinal barrier dysfunction by the elevation in the FITC-Dextran 4 kDa flux and inhibition in the transepithelial electrical resistance in a dose-dependent manner. In addition, AFB1 exposure downregulated the mRNA and protein expressions of FXR, ZO-1, occludin, and claudin-1, redistributed the ZO-1 protein, and enhanced the protein expressions of MLCK and p-MLC. However, fexaramine (Fex, FXR agonist) pretreatment markedly reversed the AFB1-induced FXR activity reduction, MLCK protein activation, and intestinal barrier impairment in vitro and in vivo. Moreover, pretreatment with the inhibition of MLCK with ML-7 significantly alleviated the AFB1-induced intestinal barrier dysfunction and tight junction disruption in vitro. In conclusion, AFB1 induced intestinal barrier impairment via regulating the FXR-mediated MLCK signaling pathway in vitro and in vivo and provided novel insights to prevent mycotoxin poisoning in the intestine.

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.