Aflatoxin M1 and ochratoxin A induce a competitive endogenous RNA regulatory network of intestinal immunosuppression by whole-transcriptome analysis

In vitro and in vivo assessment of AFB1 and OTA toxic effects and the beneficial role of bioactive compounds. A systematic review

The purpose of this review was to investigate the current knowledge about aflatoxin B1 (AFB1) and ochratoxin A (OTA) toxicity and the possible beneficial role of bioactive compounds by using in vitro and in vivo models. Although AFB1 and OTA were tested in a similar percentage, the majority of studies focused on nephrotoxicity, hepatotoxicity, immune toxicity and neurotoxicity in which oxidative stress, inflammation, structural damage and apoptosis were the main mechanisms of action reported. Conversely, several biological compounds were assayed in order to modulate mycotoxins damage mainly in the liver, brain, kidney and immune system. Among them, pumpkin, curcumin and fermented whey were the most employed. Although a clear progress has been made by using in vivo models, further research is needed to assess not only the toxicity of multiple mycotoxins contamination but also the effect of functional compounds mixture, thereby reproducing more realistic situations for human health risk assessment.

Omics analysis revealed the intestinal toxicity induced by aflatoxin B1 and aflatoxin M1

Aflatoxin B1 (AFB1), a common mycotoxin, can occur in agricultural products. As a metabolite of AFB1, aflatoxin M1 (AFM1) mainly exist in dairy products. These two mycotoxins threaten human health, although it is unclear how they affect the function of the intestinal barrier. In this study, mice were exposed to AFB1 (0.3 mg/kg body b.w.) and AFM1(3.0 mg/kg b.w.) either individually or in combination for 28 days to explore the main differentially expressed proteins (DEPs) and the associated enriched pathways. These findings were preliminarily verified by the transcriptomic and proteomic analyses in differentiated Caco-2 cells. The results revealed that AFB1 and AFM1 exposure in mice disrupted the function of the intestinal barrier, and the combined toxicity was greater than that of each toxin alone. Further proteomic analysis in mice demonstrated that the mechanisms underlying these differences could be explained as follows: (i) lipid metabolism was enriched by AFB1-induced DEPs. (ii) protein export pathway was stimulated by AFM1-induced DEPs. (iii) cell metabolic ability was inhibited (as evidenced by changes in UDP-GT1, UDP-GT2, and Gatm6), apoptosis was induced (MAP4K3), and epithelial cell integrity was disrupted (Claudin7 and IQGAP2), resulting in more extensive intestinal damage after combined treatment. In conclusion, the hazardous impact of co-exposure to AFB1 and AFM1 from proteomic perspectives was demonstrated in the present study.

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.

Ethanol responsive lnc171 promotes migration and invasion of HCC cells via mir-873-5p/ZEB1 axis

BACKGROUNDS

Long nonconding RNAs (lncRNAs) have been found to be a vital regulatory factor in the development process of human cancer, and could regarded as diagnostic or prognostic biomarkers for human cancers. Here, we aim to confirm the expression and molecular mechanism of RP11-171K16.5 (lnc171) in hepatocellular carcinoma (HCC).

METHODS

Screening of differentially expressed lncRNAs by RNA sequencing. Expression level of gene was studied by quantitative real-time PCR (qRT-PCR). The effects of lnc171, mir-873-5p, and ethanol on migration and invasion activity of cells were studied used transwell assay, and luciferase reporter assay was used to confirm the binding site.

RESULTS

RNA sequencing showed that lnc171 was markedly up-regulated in HCC. siRNA-mediated knockdown of lnc171 repressed the migration and invasion ability of HCC cells. Bioinformatic analysis, dual luciferase reporter assay, and qRT-PCR indicated that lnc171 interacted with mir-873-5p in HCC cells, and Zin-finger E-box binding homeobox (ZEB1) was a downstream target gene of mir-873-5p. In addition, lnc171 could enhance migration and invasion ability of HCC cells by up-regulating ZEB1 via sponging mir-873-5p. More interestingly, ethanol stimulation could up-regulate the increase of lnc171, thereby regulating the expression of competing endogenous RNA (ceRNA) network factors which lnc171 participated in HCC cells.

CONCLUSIONS

Our date demonstrates that lnc171 was a responsive factor of ethanol, and plays a vital role in development of HCC via binding of mir-873-5p.

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.

Antiapoptotic and chemotaxis-stimulating effects of poly (D, L-lactide-co-glycolide)-chitosan and whey proteins against aflatoxicosis-induced splenic and thymic atrophy

BACKGROUND

Aflatoxin B (AFB) induces toxicological effects on the liver and immune organs. The whey proteins can modulate the immune response during aflatoxicosis. Our work evaluates the novel polylactic acid-glycolic acid-chitosan-encapsulated bovine and camel whey proteins against AFB-induced thymic and splenic atrophy in rats.

METHODS AND RESULTS

Seventy adult male Wister albino rats were divided into a control healthy group (G1) and six AFB1-intoxicated groups (G2-G7). One of the following supplements: distilled water, camel whey proteins (CWP), bovine whey proteins, poly (D, L-lactide-co-glycolide) (PLGA)- chitosan-loaded with camel whey protein microparticles (CMP), PLGA-chitosan loaded with bovine whey protein microparticles (BMP), and PLGA-chitosan nanoparticles were administered as prophylactic supplements to AFB1-intoxicated groups. The AFB-treated group showed significantly higher hepatic levels of oxidative stress and lower levels of antioxidants. In the aflatoxicated group, atrophy of the splenic lymphatic nodules and disfigurement in the organisation with an apparent decrease in the thickness of the cortex in the thymus were observed, as well as a decrease in splenic and thymic CD4+T and CD8+T lymphocytes. Moreover, CXCL12 levels were downregulated, whereas tumour necrosis factor-alpha, nuclear factor kappa B, and cleaved caspase-3 levels were upregulated. CWP, BMP, and CMP supplements markedly decreased oxidative stress, inflammation, and apoptosis, as well as significantly raised CXCL12, CD4+T, and CD8+T cells.

CONCLUSIONS

The CWP, BMP, and CMP supplements rescue the liver and immune tissues from the toxic effects of AFB through their antioxidant, antiapoptotic, anti-inflammatory, and chemotaxis-enhancing roles.

Prediction and validation of enzymatic degradation of aflatoxin M1: Genomics and proteomics analysis of Bacillus pumilus E-1-1-1 enzymes

Aflatoxins are a class of highly toxic mycotoxins. Aflatoxin M1 (AFM1) is hydroxylated metabolite of aflatoxin B1, having comparable toxicity, which is more commonly found in milk. In this study, the whole genome sequencing of Bacillus pumilus E-1-1-1 isolated from feces of 38 kinds of animals, having aflatoxin M1 degradation ability was conducted. Bacterial genome sequencing indicated that a total of 3445 sequences were finally annotated on 23 different cluster of orthologous groups (COG) categories. Then, the potential AFM1 degradation proteins were verified by proteomics; the properties of these proteins were further explored, including protein molecular weight, hydrophobicity, secondary structure prediction, and three-dimensional structures. Bacterial genome sequencing combined with proteomics showed that eight genes were the most capable of degrading AFM1 including three catalases, one superoxide dismutase, and four peroxidases to clone. These eight genes with AFM1 degrading capacity were successfully expressed. These results indicated that AFM1 can be degraded by Bacillus pumilus E-1-1-1 protein and the most degrading proteins were oxidoreductases.

Insights into the intestinal toxicity of foodborne mycotoxins through gut microbiota: A comprehensive review

Mycotoxins, which are fungal metabolites, pose a significant global food safety concern by extensively contaminating food and feed, thereby seriously threatening public health and economic development. Many foodborne mycotoxins exhibit potent intestinal toxicity. However, the mechanisms underlying mycotoxin-induced intestinal toxicity are diverse and complex, and effective prevention or treatment methods for this condition have not yet been established in clinical and animal husbandry practices. In recent years, there has been increasing attention to the role of gut microbiota in the occurrence and development of intestinal diseases. Hence, this review aims to provide a comprehensive summary of the intestinal toxicity mechanisms of six common foodborne mycotoxins. It also explores novel toxicity mechanisms through the "key gut microbiota-key metabolites-key targets" axis, utilizing multiomics and precision toxicology studies with a specific focus on gut microbiota. Additionally, we examine the potential beneficial effects of probiotic supplementation on mycotoxin-induced toxicity based on initial gut microbiota-mediated mycotoxicity. This review offers a systematic description of how mycotoxins impact gut microbiota, metabolites, and genes or proteins, providing valuable insights for subsequent toxicity studies of mycotoxins. Furthermore, it lays a theoretical foundation for preventing and treating intestinal toxicity caused by mycotoxins and advancing food safety practices.

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

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

Elucidating the toxicity mechanism of AFM2 and the protective role of quercetin in albino mice

Aflatoxin M2 (AFM2) is a type of mycotoxin detected in milk or dairy products from animals consuming contaminated feed. In this study, the toxicity mechanism of AFM2 and the protective effects of quercetin were investigated in albino mice. For this purpose, the mice were divided into 6 groups and the groups were fed with quercetin and AFM2. The toxic effects of AFM2 and the protective properties of quercetin were investigated using physiological, biochemical and cytogenetic parameters. The genotoxic mechanism of AFM2 and the protective role of quercetin were investigated by molecular docking, which is an in silico model. As a result, 16 mg/kg b.w AFM2 administration caused serious changes in body weight, organ index, kidney and liver weight, and deterioration of antioxidant/oxidant balance in liver and kidney organs. The decrease in glutathione levels along with an increase in malondialdehyde (MDA) levels in the liver and kidney after AFM2 administration indicates that oxidative stress is induced. The increases in alanine transaminase (ALT) and aspartat transaminase (AST) levels, which are indicators of liver damage, and the increases in serum levels of blood urea nitrogen (BUN) and creatinine, which are indicators of kidney damage, confirm the damage in both organs. AFM2 also caused genotoxicity by inducing micronucleus (MN) and chromosomal abnormalities (CAs) in bone marrow tissue. It has been determined that AFM2, which exhibits genotoxicity as a result of its clastogenic and aneugenic effects, causes CAs by interacting with DNA. Quercetin provided significant protection by improving liver and kidney tissues, partial normalization in serum parameter levels, and severe reductions in MN and CAs. The highest protection was determined as 74.1% against dicentric chromosome formations in 50 mg/kg b.w quercetin application. The interaction of quercetin with xanthine oxidase and nitric oxide synthase enzymes was determined in silico with an inhibition constant in the range of 283.71-476.17 nM. These interactions cause changes in the activity of enzymes, reducing the oxidative load in the cell, and in this way, quercetin provides protection. All toxic effects induced by AFM2 were decreased with quercetin administration dose-dependently, and this protective effect was associated with quercetin's reduction of oxidative load by inhibiting the free radical-producing enzyme. All toxic effects caused by AFM2 were decreased with quercetin administration in a dose-dependent manner, and this protective effect was associated with quercetin's reduction of oxidative load by inhibiting the enzyme that produces free radicals.

Hypoxia and Cellular Senescence, Emerging Toxic Mechanisms of Mycotoxins and Toxins: A New Understanding of the Negative Immune Regulations

Mycotoxin contamination is an important issue that has plagued the world [...]