Proteomics reveals the alleviation of zinc towards aflatoxin B1-induced cytotoxicity in human hepatocyes (HepG2 cells)

Near-infrared light triggered bio-inspired enhanced natural silk fibroin nanofiber composite scaffold for photothermal therapy of periodontitis

Periodontitis is one of the major oral health issues worldwide, with significant impacts on oral health and patients's quality of life, but current therapies have not achieved optimal regeneration of periodontal tissue. This study developed scaffolds using natural tussah silk fibroin (TSF) cross-linked with regenerated silk fibroin (SF) nanofibers to improve mechanical properties and wet-state stability. Zinc oxide (ZnO) and polydopamine (PDA) composite nanoparticles were loaded into scaffold to impart its antibacterial and photothermal properties to construct a photo-responsive composite scaffold (ZnO/PDA/TSF-SF). After characterization, ZnO/PDA/TSF-SF demonstrated excellent antibacterial ability, biocompatibility, and photothermal stability. In vitro cell evaluations under 635 nm red light irradiation-mediated photo-biomodulation (PBM) demonstrated that ZnO/PDA/TSF-SF promoted fibroblast proliferation and enhanced expression of proteins and genes associated with tissue repair, such as collagen I (Col I), fibronectin (FN), and alpha smooth muscle actin (α-SMA). A rat model of periodontitis developed for evaluations of antibacterial and tissue repair effects showed that ZnO/PDA/TSF-SF improved alveolar bone and reversed bone loss. ZnO/PDA/TSF-SF improved inflammation significantly through reduction in tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), and IL-6 levels in serum and gingival tissues of modeled rats. Also, the scaffold markedly increased levels of anti-inflammatory cytokine interleukin-10 (IL-10) and elevated protein and mRNA expression levels of tissue repair-related proteins and endothelial cell markers. ZnO/PDA/TSF-SF scaffold exhibited good biocompatibility, osteogenesis, and photo-responsive antibacterial properties, thereby demonstrating therapeutic potential in treating periodontitis.

The impact of aflatoxin B1 on animal health: Metabolic processes, detection methods, and preventive measures

Aflatoxin (AF) is a toxic metabolite produced by the fungus Aspergillus. The various subtypes of AFs include B1, B2, G1, G2, M1, and M2, with Aflatoxin B1 (AFB1) being the most toxic. These AFs are widespread in the environment, particularly in soil and food crops. The World Health Organization (WHO) has classified AFB1 as a highly potent natural Class 1A carcinogen. Excessive exposure to AFB1 can lead to poisoning in both humans and animals, posing substantial risks to food safety and livestock breeding industries. This review provides an overview of the metabolic processes, detection methods, and the detrimental impacts of AFB1 on animal reproduction, immunity, nerves, intestines, and metabolism. Furthermore, it explores the preventive and control capacities of natural active substances, trace elements, and microorganisms against AFB1. Ultimately, this paper serves as a reference for further research on the pathogenic mechanism of AFB1, the development of preventive drugs, and the selection of effective detoxification measures for AFB1 in animal feed.

Some relevant mitigating agents of chronic aflatoxin exposure: a treatise

Aflatoxins, a group of toxic secondary metabolites produced by Aspergillus species, pose significant threats to human health due to their potent carcinogenic, mutagenic, and immunosuppressive properties. Chronic exposure to these contaminants, commonly found in staple foods such as maize and groundnuts, has been linked to an increased risk of liver cancer, growth impairment, and immune dysfunction. Several agents, such as calcium montmorillonite clay and Lactobacillus rhamnosus GG, have shown promise in reducing aflatoxin bioavailability and alleviating its toxic effects. Additionally, dietary supplements such as chlorophyllin, selenium, and N-acetylcysteine have demonstrated potential as adjuvants to counteract aflatoxin-induced oxidative stress and support liver function. In this treatise, some of the most discussed approaches to mitigating aflatoxin effects are explored in terms of their efficacy, safety, and potential mechanisms of action, which include direct aflatoxin binding, detoxification, cellular antioxidative, and hepatocellular protection properties. However, the effectiveness of these strategies can be influenced by various factors, such as dose, duration of exposure, and individual susceptibility. Therefore, further research is needed to optimize these interventions and develop new, targeted therapies for the prevention and treatment of aflatoxin-related diseases. This review aims to provide a comprehensive analysis of 18 pharmaceutical, nutraceutical, supplement, and probiotic strategies currently available for mitigating the deleterious effects of chronic aflatoxin exposure in humans and animal models.

Fluorescent solid-state strips based on SiO2 shell-stabilized perovskite nanocrystals applying for magnetic aptasensing detection of aflatoxin B1 toxin in food

In this work, the perovskite fluorescent nanocrystals (CsPbBr3) were successfully synthesized and wrapped with SiO2 shell, utilized for the assembly of solid-state detection strip capable of conveniently and specifically detection of aflatoxin B1 (AFB1). The SiO2 coating aimed to enhance the stability of CsPbBr3 nanocrystals. The resulting CsPbBr3@SiO2 material exhibited remarkable fluorescence properties, and further self-assembled onto solid-state plate, generating AFB1-specific quenched fluorescence at a specific wavelength of 515 nm. When combined with the capture of AFB1 by magnetic nanoparticles conjugated with aptamers (MNPs-Apt), it was achieved the good separation and specific detection of AFB1 toxin in food matrices. The constructed fluorescent solid-state detection strip based on CsPbBr3@SiO2 exhibited good response to AFB1 toxin within a linear range of 0.1-100 ng mL-1 and an impressive detection limit as low as 0.053 ng mL-1. This presents a new strategy for the rapid screening and convenient detection of highly toxic AFB1.

Co-contamination and interactions of multiple mycotoxins and heavy metals in rice, maize, soybeans, and wheat flour marketed in Shanghai City

Mycotoxins and heavy metals extensively contaminate grains and grain products, posing severe health risks. This work implements validated ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and inductively coupled plasma mass spectrometry (ICP-MS) methods to quantify the concentration of 12 mycotoxins and five heavy metals in rice, maize, soybeans, and wheat flour samples marketed in Shanghai. The mixed contamination characteristics were analyzed using correlation cluster analysis and co-contamination index, and the probabilities of all cross combinations of contaminations were analyzed using a self-designed JAVA language program. The results showed that grains and grain products were frequently contaminated with both mycotoxins and heavy metals, mostly with deoxynivalenol (DON), 3-acetyl-deoxynivalenol (3-ADON), 15-acetyl-deoxynivalenol (15-ADON), ochratoxin A (OTA), aflatoxins, fumonisin B1 (FB1), fumonisin B2 (FB2), fumonisin B3 (FB3), arsenic (As), chromium (Cr) and cadmium (Cd). All the samples (100 %) were contaminated with two or more contaminants, and 77.3 % of the samples were co-contaminated with more than four contaminants. In cereals and cereal products, the following combinations were closely associated: (FB3 +3-ADON), (FB1 +As), (FB1 +FB2), (DON+FB1), (DON+Cd), (As+Cd), (DON+Cd+As), (FB1 +FB2 +As), and (DON+3-ADON+15-ADON). The results indicated that mycotoxins and heavy metals frequently co-occurred in Shanghai grains and grain products, and they provided primary data for safety assessments, early warnings, and regulatory measures on these contaminants to protect public health.

Abdallah M, Chen X, Rajkovic A. Current Knowledge of Individual and Combined Toxicities of Aflatoxin B1 and Fumonisin B1 In Vitro

Mycotoxins are considered the most threating natural contaminants in food. Among these mycotoxins, aflatoxin B1 (AFB1) and fumonisin B1 (FB1) are the most prominent fungal metabolites that represent high food safety risks, due to their widespread co-occurrence in several food commodities, and their profound toxic effects on humans. Considering the ethical and more humane animal research, the 3Rs (replacement, reduction, and refinement) principle has been promoted in the last few years. Therefore, this review aims to summarize the research studies conducted up to date on the toxicological effects that AFB1 and FB1 can induce on human health, through the examination of a selected number of in vitro studies. Although the impact of both toxins, as well as their combination, were investigated in different cell lines, the majority of the work was carried out in hepatic cell lines, especially HepG2, owing to the contaminants' liver toxicity. In all the reviewed studies, AFB1 and FB1 could invoke, after short-term exposure, cell apoptosis, by inducing several pathways (oxidative stress, the mitochondrial pathway, ER stress, the Fas/FasL signaling pathway, and the TNF-α signal pathway). Among these pathways, mitochondria are the primary target of both toxins. The interaction of AFB1 and FB1, whether additive, synergistic, or antagonistic, depends to great extent on FB1/AFB1 ratio. However, it is generally manifested synergistically, via the induction of oxidative stress and mitochondria dysfunction, through the expression of the Bcl-2 family and p53 proteins. Therefore, AFB1 and FB1 mixture may enhance more in vitro toxic effects, and carry a higher significant risk factor, than the individual presence of each toxin.

Aflatoxin B1 exposure triggers hepatic lipotoxicity via p53 and perilipin 2 interaction-mediated mitochondria-lipid droplet contacts: An in vitro and in vivo assessment

Aflatoxin B1 (AFB1) is one of the most toxic mycotoxins widely found in food contaminants, and its target organ is the liver. It poses a major food security and public health threat worldwide. However, the lipotoxicity mechanism of AFB1 exposure-induced liver injury remains unclear and requires further elucidation. Herein, we investigated the potential hepatic lipotoxicity of AFB1 exposure using in vitro and in vivo models to assess the public health hazards of high dietary AFB1 exposure. We demonstrated that low-dose of AFB1 (1.25 μM for 48 h, about one-fifth of the IC50 in HepG2 and HepaRG cells, IC50 are 5.995 μM and 5.266 μM, respectively) exposure significantly induced hepatic lipotoxicity, including abnormal lipid droplets (LDs) growth, mitochondria-LDs contacts increase, lipophagy disruption, and lipid accumulation. Mechanistically, we showed that AFB1 exposure promoted the mitochondrial p53 (mito-p53) and LDs-associated protein perilipin 2 (PLIN2) interaction-mediated mitochondria-LDs contacts, resulting in lipid accumulation in hepatocytes. Mito-p53-targeted inhibition, knockdown of PLIN2, and rapamycin application efficiently promoted the lysosome-dependent lipophagy and alleviated the hepatic lipotoxicity and liver injury induced by AFB1 exposure. Overall, our study found that mito-p53 and PLIN2 interaction mediates three organelles-mitochondria, LDs, and lysosomal networks to regulate lipid homeostasis in AFB1 exposure-induced hepatotoxicity, revealing how this unique trio of organelles works together and provides a novel insight into the targeted intervention in inter-organelle lipid sensing and trafficking for alleviating hazardous materials-induced hepatic lipotoxicity.

The Impact of Zinc on Manganese Bioavailability and Cytotoxicity in HepG2 Cells

SCOPE

Despite their essentiality, several studies have shown that either manganese (Mn) or zinc (Zn) overexposure may lead to detrimental health effects. Although Mn is transported by some of the SLC family transporters that translocate Zn, the role of Zn in hepatocellular Mn transport and Mn-induced toxicity have yet to be fully characterized.

METHODS AND RESULTS

The human hepatoma cell line, HepG2, is utilized. Total cellular Mn and Zn amounts are determined after cells are treated with Zn 2 or 24 h prior to Mn incubation for additional 24 h with inductively coupled plasma-based spectrometry and labile Zn is assessed with the fluorescent probe FluoZin-3. Furthermore, mRNA expression of genes involved in metal homeostasis, and mechanistic endpoints associated with Mn-induced cytotoxicity are addressed. These results suggest that Zn protects against Mn-induced cytotoxicity and impacts Mn bioavailability to a great extent when cells are preincubated with higher Zn concentrations for longer duration as characterized by decreased activation of caspase-3 as well as lactate dehydrogenase (LDH) release.

CONCLUSIONS

Zn protects against Mn-induced cytotoxicity in HepG2 cells possibly due to decreased Mn bioavailability. Additionally, mRNA expression of metal homeostasis-related genes indicates possible underlying pathways that should to be addressed in future studies.

Aflatoxin B1 Exposure in Sheep: Insights into Hepatotoxicity Based on Oxidative Stress, Inflammatory Injury, Apoptosis, and Gut Microbiota Analysis

The widespread fungal toxin Aflatoxin B₁ (AFB₁) is an inevitable pollutant affecting the health of humans, poultry, and livestock. Although studies indicate that AFB₁ is hepatotoxic, there are few studies on AFB₁-induced hepatotoxicity in sheep. Thus, this study examined how AFB₁ affected sheep liver function 24 h after the animals received 1 mg/kg bw of AFB₁ orally (dissolved in 20 mL, 4% v/v ethanol). The acute AFB₁ poisoning caused histopathological injuries to the liver and increased total bilirubin (TBIL) and alkaline phosphatase (AKP) levels. AFB₁ also markedly elevated the levels of the pro-inflammatory cytokines TNF-α and IL-6 while considerably reducing the expression of antioxidation-related genes (SOD-1 and SOD-2) and the anti-inflammatory gene IL-10 in the liver. Additionally, it caused apoptosis by dramatically altering the expression of genes associated with apoptosis including Bax, Caspase-3, and Bcl-2/Bax. Notably, AFB₁ exposure altered the gut microbiota composition, mainly manifested by BF311 spp. and Alistipes spp. abundance, which are associated with liver injury. In conclusion, AFB₁ can cause liver injury and liver dysfunction in sheep via oxidative stress, inflammation, apoptosis, and gut-microbiota disturbance.

The importance of transcriptomics and proteomics for studying molecular mechanisms of mycotoxin exposure: A review

This review aims to highlight recent advances where transcriptomics and proteomics have been used as a key tool to understand molecular toxicity of mycotoxins. The most studied mycotoxin by using transcriptomic approach is deoxynivalenol (DON), followed by aflatoxins (AFs) and zearalenone (ZEA). Instead, proteomics mostly focuses on AFs but also in this case, mildly to ZEA and DON. However, in both omics approaches, fewer studies investigated the toxicological effect of emerging mycotoxins, patulin, ochratoxin A, T-2 toxin, alternariol and amino-14,16-dimethyloctadecan-3-ol. The study of changes in the expression of genes involved in immune system are the most common purposes for transcriptomics whereas cellular processes in proteomics field. Concerning the techniques used to perform the experiments, RT-qPCR is the most employed in gene expression analysis whereas liquid chromatography coupled with mass spectrometry is the master technique for proteomics assays. The gathered data have reported that the interest in using these omic approaches has increased in the last five years. However, in vitro models take precedence over the in vivo and ex vivo ones. Therefore, there is a need to enhance the use of in vivo models and alternative methods to better understand mycotoxins mode of action on animal and human health.

Deepening the Whole Transcriptomics of Bovine Liver Cells Exposed to AFB1: A Spotlight on Toll-like Receptor 2

Aflatoxin B1 (AFB1) is a food contaminant metabolized mostly in the liver and leading to hepatic damage. Livestock species are differently susceptible to AFB1, but the underlying mechanisms of toxicity have not yet been fully investigated, especially in ruminants. Thus, the aim of the present study was to better characterize the molecular mechanism by which AFB1 exerts hepatotoxicity in cattle. The bovine fetal hepatocyte cell line (BFH12) was exposed for 48 h to three different AFB1 concentrations (0.9 µM, 1.8 µM and 3.6 µM). Whole-transcriptomic changes were measured by RNA-seq analysis, showing significant differences in the expression of genes mainly involved in inflammatory response, oxidative stress, drug metabolism, apoptosis and cancer. As a confirmatory step, post-translational investigations on genes of interest were implemented. Cell death associated with necrosis rather than apoptosis events was noted. As far as the toxicity mechanism is concerned, a molecular pathway linking inflammatory response and oxidative stress was postulated. Toll-Like Receptor 2 (TLR2) activation, consequent to AFB1 exposure, triggers an intracellular signaling cascade involving a kinase (p38β MAPK), which in turn allows the nuclear translocation of the activator protein-1 (AP-1) and NF-κB, finally leading to the release of pro-inflammatory cytokines. Furthermore, a p38β MAPK negative role in cytoprotective genes regulation was postulated. Overall, our investigations improved the actual knowledge on the molecular effects of this worldwide relevant natural toxin in cattle.

Functional Characterization and Whole-Genome Analysis of an Aflatoxin-Degrading Rhodococcus pyridinivorans Strain

Simple Summary

The microbiological degradation of AFB₁ has been a promising approach to control AFB₁ contamination. Here, we characterize a Rhodococcus pyridinivorans strain that can efficiently degrade AFB₁. The AFB₁-degrading capacity of this bacterial strain was characterized, and the completed genome was sequenced and analyzed. Further proteomic analyses of this strain identified a total of 723 proteins in an extracellular component that showed the strongest capacity to degrade AFB₁ (degradation rate 83.7%). Multiple potential AFB₁-degrading enzymes, and enzymes that are reported to respond to AFB₁ treatment, have been identified accordingly. These findings provide a genomic, proteomic, and experimental approach for characterizing an efficient AFB₁-degrading bacterial strain with great potential for use in the remediation of AFB₁ contamination.

Abstract

Aflatoxin B₁ (AFB₁) is one of the most toxic, naturally occurring carcinogen compounds and is produced by specific strains of fungi. Crop contamination with AFB₁ can cause huge economic losses and serious health problems. Many studies have examined the microbiological degradation of AFB₁, especially the use of efficient AFB₁-degrading microorganisms, to control AFB₁ contamination. Here, we reported the identification of a new Rhodococcus pyridinivorans strain (4-4) that can efficiently degrade AFB₁ (degradation rate 84.9%). The extracellular component of this strain showed the strongest capacity to degrade AFB₁ (degradation rate 83.7%). The effects of proteinase K, SDS, temperature, pH, incubation time, and AFB₁ concentration on the AFB₁ degradation ability of the extracellular component were investigated. We sequenced the complete genome of this strain, encoding 5246 protein-coding genes and 169 RNA genes on a circular chromosome and two plasmids. Comparative genomic analysis revealed high homology with other Rhodococcus strains with high AFB₁-degradation ability. Further proteomic analyses of this strain identified a total of 723 proteins in the extracellular component, including multiple potential AFB₁-degrading enzymes, along with enzymes that are reported to response to AFB₁ treatment. Overall, the results demonstrate that R. pyridinivorans 4-4 would be an excellent candidate for the biodegradation and detoxification of AFB₁ contamination.

Coexposure of Cyclopiazonic Acid with Aflatoxin B1 Involved in Disrupting Amino Acid Metabolism and Redox Homeostasis Causing Synergistic Toxic Effects in Hepatocyte Spheroids

Cyclopiazonic acid (CPA), an emerging toxin, has been found in various foods such as corn, peanuts, and figs. Aspergillus flavus can produce CPA, leading to coexposure with highly toxic aflatoxin B1 (AFB1), but the mechanism of their combined action is not clear. In this study, cocultured hepatocyte spheroids were used as the evaluation model, and two concentration settings of isotoxicity and different toxicity ratios were used to investigate the combined toxic effects. Metabolomics was subsequently used to analyze the potential mechanisms underlying the effects of their exposure. AFB1 and CPA might exhibit stronger cytotoxicity, with significant combined effects on mitochondrial morphology, activity, and reactive oxygen levels. The gene expression analysis revealed that the overexpression of AKT genes could mitigate the combined effects of AFB1 and CPA to some extent. Metabolomics analysis indicated that AFB1 and CPA significantly downregulated the metabolism of l-aspartate and antioxidant substances (e.g., penicillamine, myricetin, and ethanolamine). The pathway enrichment analysis also revealed a large impact on amino acid metabolism, likely affecting intracellular redox homeostasis. In addition, the presence of CPA affects intracellular glucose metabolism and lipid metabolism pathways. This study suggested a direction for future research on relevant toxic pathways and provided possible ideas for inhibiting or mitigating toxicity.

A HepG2 Cell-Based Biosensor That Uses Stainless Steel Electrodes for Hepatotoxin Detection

Humans are frequently exposed to environmental hepatotoxins, which can lead to liver failure. Biosensors may be the best candidate for the detection of hepatotoxins because of their high sensitivity and specificity, convenience, time-saving, low cost, and extremely low detection limit. To investigate suitability of HepG2 cells for biosensor use, different methods of adhesion on stainless steel surfaces were investigated, with three groups of experiments performed in vitro. Cytotoxicity assays, which include the resazurin assay, the neutral red assay (NR), and the Coomassie Brilliant Blue (CBB) assay, were used to determine the viability of HepG2 cells exposed to various concentrations of aflatoxin B1 (AFB1) and isoniazid (INH) in parallel. The viability of the HepG2 cells on the stainless steel surface was quantitatively and qualitatively examined with different microscopy techniques. A simple cell-based electrochemical biosensor was developed by evaluating the viability of the HepG2 cells on the stainless steel surface when exposed to various concentrations of AFB1 and INH by using electrochemical impedance spectroscopy (EIS). The results showed that HepG2 cells can adhere to the metal surface and could be used as part of the biosensor to determine simple hepatotoxic samples.

Application of triple co-cultured cell spheroid model for exploring hepatotoxicity and metabolic pathway of AFB1

The toxicity evaluation suffers from the absence of suitable models capable of replicating in the co-cultured cell microenvironment and the function of specific tissues in vitro. Motivated by this urgent need, this study aimed to describe a novel three-dimensional (3D) liver spheroid model. The model consisted of a triple co-culture of HepG2, EA.hy 926, and LX-2. Subsequently, it was used for the toxicity evaluation of aflatoxin B1 (AFB1), and its advantages over the two-dimensional (2D) model and the mono-type cell spheroid model were assessed. This study examined the effects of AFB1 on cell viability, proliferation, mitochondria, oxidative stress, and cell membranes. The results revealed that AFB1 greatly affected 2D cell membranes and oxidative stress levels (0.01 μg/mL; 24 h), and could also significantly affect 2D cell viability, proliferation, and mitochondria levels (1 μg/mL; 24 h). On the contrary, 3D cells were less susceptible to AFB1. Combined with the analysis of gene expression, both metabolic activation (cytochrome P450; CYP450) and detoxification efficiency (drug-metabolizing enzymes) were found to be higher in 3D cells than in 2D cells. Moreover, 3D cells in triple co-culture outperformed mono-type cell spheroids. Therefore, the advanced 3D co-cultured spheroid model constructed in this study allowed us to more realistically simulate the microenvironment in vitro, and was a valuable and precise model to study mycotoxins.

Penthorum Chinense Pursh Extract Alleviates Aflatoxin B1-Induced Liver Injury and Oxidative Stress Through Mitochondrial Pathways in Broilers

Aflatoxin is an important toxicant of the fungal origin and poses a threat to the poultry industry. This study was designed to reveal the underlying mechanism and protective methods against aflatoxin B1 (AFB1)-induced liver injury, oxidative stress, and apoptosis using a Traditional Chinese medicine, Penthorum chinense Pursh extract (PCPE), in broilers. A total of 164 (day-old) broilers were equally allocated to the control, AFB1 (3 mg/kg feed), positive drug (Yin-Chen-Hao Tang extract, 10 ml/kg feed), PCPE (2 g PCPE/kg), and PCPE low, medium, and high dose groups (1 g, 2 g, 3 g PCPE/kg feed, respectively). AFB1 significantly decreased the growth performance and serum immunoglobulin level, altered normal serum biochemical parameters and antioxidant activities, and induced histopathological lesions in the liver as compared to control group. Additionally, AFB1 significantly up-regulated the mRNA expression levels of apoptosis-related genes such as Bax, Bak, caspase-9, caspase-3, and p53, whereas it down-regulated the expression levels of BCL2 in the liver of broilers. The supplementation of different doses of PCPE to AFB1-affected birds significantly eased AFB1 negative effects by improving growth performance, immunoglobulin level, and oxidative capacity, and reversed oxidative stress and pathological lesions in liver. Furthermore, supplementation of PCPE to the AFB1 group reversed apoptosis by significantly down-regulating the mRNA expression levels of Bax, Bak, caspase-9, caspase-3, and p53 and up-regulating the expression levels of BCL2 in the liver of broilers. Based on these results, we conclude that supplementation of PCPE is protective and safe against oxidative stress, is anti-apoptotic, and reverses the liver damage caused by AFB1 in broilers.

Total flavonoids of Rhizoma Drynariae protect hepatocytes against aflatoxin B1-induced oxidative stress and apoptosis in broiler chickens

Aflatoxin B1 (AFB1) is a common mycotoxin in food and in the environment that lead to multi-organ injury in humans and animals. The objective of this study was to evaluate the detoxification properties of dietary total flavonoids of Rhizoma drynariae (TFRD), a Chinese herbal, on aflatoxin B1 (AFB1)-induced hepatic oxidative damage and apoptosis of liver of broiler chickens. A total of 160 healthy specific pathogen free (SPF) 21-day-old broilers were randomly allocated to 4 groups, including the CON group (basal diet), TFRD group (basal diet with 125 mg/kg TFRD), AFB1 group (100 μg/kg body weight), and AFB1 (100 μg/kg body weight) + TFRD (basal diet with 125 mg/kg TFRD) group. The exposure of AFB1 continued for seven days. The results showed that TFRD treatment alleviated the abnormal changes of growth performance and liver morphology, reduced serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels. Moreover, TFRD promoted the antioxidant capacity of serum, increased the activities of total superoxide dismutase (T-SOD), oxidized glutathione (GSSG) and glutathione (GSH) (p < 0.05), while decreased MDA contents (p > 0.05). Meanwhile, supplementation of TFRD significantly increased the expression of antioxidant-related genes (SOD, CAT, GST, and GPX1) in liver (p < 0.05). Furthermore, we found that AFB1 was involved in the regulation of PI3K/AKT signaling pathway, leading to hepatocyte apoptosis. At the same time, TFRD treatment inhibited AFB1-induced apoptosis and significantly changed mRNA expression of apoptosis-related genes, including PI3K, AKT, Bax, and Bcl-2 (p < 0.05). The results indicated that TFRD could alleviate AFB1-induced liver injury in broiler chickens.

Penthorum chinense Pursh Compound Ameliorates AFB1-Induced Oxidative Stress and Apoptosis via Modulation of Mitochondrial Pathways in Broiler Chicken Kidneys

Aflatoxin B1 (AFB1) is a carcinogenic mycotoxin widely present in foods and animal feeds; it represents a great risk to human and animal health. The aim of this study was to investigate the protective effects of Penthorum chinense Pursh compound (PCPC) against AFB1-induced damage, oxidative stress, and apoptosis via mitochondrial pathways in kidney tissues of broilers. One-day-old chickens (n = 180) were randomly allocated to six groups: control, AFB1 (2.8 mg AFB1/kg feed), positive drug (10 mLYCHT/kg feed), and PCPC high, medium, and low-dose groups (15, 10, and 5 ml PCPC/kg feed, respectively). AFB1 treatment reduced weight gain and induced oxidative stress and kidney damage in broiler tissues; however, PCPC supplementation effectively enhanced broiler performance, ameliorated AFB1-induced oxidative stress, and inhibited apoptosis in the kidneys of broilers. The mRNA expression levels of mitochondria-related apoptosis genes (Bax, Bak, cytochrome c, caspase-9, and caspase-3) were significantly increased, whereas BCL2 expression level decreased in the AFB1 group. Supplementation of PCPC to the AFB1 group significantly reversed the changes in mRNA expression levels of these apoptosis-associated genes compared to those in the AFB1 group. The mRNA levels of NRF2 and HMOX1 in the kidneys of the AFB1 group were significantly reduced compared to those in the control group, whereas PCPC significantly increased the NRF2 and HMOX1 mRNA levels. AFB1 decreased the levels of Beclin1, LC3-I, and LC3-II and increased P53 levels in the kidney compared to those in the control, whereas PCPC significantly reversed these changes to normal levels of autophagy-related genes compared to those in the AFB1 group. In conclusion, our findings demonstrated that PCPC ameliorated AFB1-induced oxidative stress by regulating the expression of apoptosis-related genes and mitochondrial pathways. Our results suggest that PCPC represents a natural and safe agent for preventing AFB1-induced injury and damage in broiler tissues.

Proteomic profiling and glycomic analysis of the yeast cell wall in strains with Aflatoxin B1 elimination ability

The use of microorganisms for Aflatoxin B₁ elimination has been studied as a new alternative tool and it is known that cell wall carried out a critical role. For that reason, cell wall and soluble intracellular fraction of eight yeasts with AFB₁ detoxification capability were analysed. The quantitative and qualitative comparative label-free proteomic allowed the identification of diverse common constituent proteins, which revealed that putative cell wall proteins entailed less than 10% of the total proteome. It was possible to characterize different enzymes linked to cell wall polysaccharides biosynthesis as well as other proteins related with the cell wall organization and regulation. Additionally, the concentration of the principal polysaccharides was determined which permitted us to observe that β-glucans concentration was higher than mannans in most of the samples. In order to better understand the biosorption role of the cell wall against the AFB₁ , an antimycotic (Caspofungin) was used to damage the cell wall structure. This assay allowed the observation of an effect on the normal growth of those yeasts with damaged cell walls that were exposed to AFB₁ . This effect was not observed in yeast with intact cell walls, which may reveal a protective role of this structure against mycotoxins.

Transcriptomics and flow cytometry reveals the cytotoxicity of aflatoxin B1 and aflatoxin M1 in bovine mammary epithelial cells

Aflatoxin is a known mycotoxin that pollutes various grains widely in the environment. Aflatoxin B₁ (AFB₁) and Aflatoxin M₁ (AFM₁) have been shown to induce cytotoxicity in many cells, yet their effects on mammary epithelial cells remain unclear. In this study, we examined the toxicity and the effects of AFB₁ and AFM₁ on bovine mammary epithelial cells (BME cells). The cells were treated with AFB₁ or AFM₁ at a concentration of 0-10 mg/L for 24 or 48 h, followed by cytotoxicity assays, flow cytometry, and transcriptomics. Our results demonstrated that AFB₁ and AFM₁ induced cell proliferation inhibition, apoptosis and cell cycle arrest. However, the level of intracellular reactive oxygen species has no significant difference. The RNA-Seq results also showed that AFB₁ and AFM₁ changed many related gene expressions like apoptosis and oxidative stress, cycle, junction, and signaling pathway. Taken together, AFB₁ and AFM₁ were found to affect cytotoxicity and related gene changes in BME cells. Notably, this study reported that 2 mg/L of AFB₁ and AFM₁ affected the expression of methylation-related genes, and ultimately altered the rate of m⁶A methylation in RNA. It may provide a potential direction for toxins to indirectly regulate gene expression by affecting RNA methylation modification. Our research provides some novel insights and data about AFB₁ and AFM₁ toxicity in BME cells.