Interaction of aflatoxin B 1 and fumonisin B 1 in HepG2 cell apoptosis

Biological Detoxification of Aflatoxin B1 by Enterococcus faecium HB2-2

Aflatoxin B1 (AFB1) contamination in food and feed is a global health and economic threat, necessitating the immediate development of effective strategies to mitigate its negative effects. This study focuses on the isolation and characterization of Enterococcus faecium HB2-2 (E. faecium HB2-2) as a potent AFB1-degrading microorganism, using morphological observation, biochemical profiling, and 16S rRNA sequence analysis. An incubation of E. faecium HB2-2 at 32 °C for 96 h in a pH 10 nutrient broth (NB) medium resulted in a remarkable degradation rate of 90.0% for AFB1. Furthermore, E. faecium HB2-2 demonstrated 82.9% AFB1 degradation rate in the peanut meal, reducing AFB1 levels from 105.1 to 17.9 μg/kg. The AFB1 degradation ability of E. faecium HB2-2 was found to be dependent on the fermentation supernatant. The products of AFB1 degradation by E. faecium HB2-2 were analyzed by liquid chromatography-mass spectrometry (LC-MS), and a possible degradation mechanism was proposed based on the identified degradation products. Additionally, cytotoxicity assays revealed a significant reduction in the toxicity of the degradation products compared to the parent AFB1. These findings highlight the potential of E. faecium HB2-2 as a safe and effective method for mitigating AFB1 contamination in food and feed.

The relationship between aflatoxin B1 with the induction of extrinsic/intrinsic pathways of apoptosis and the protective role of taraxasterol in TM3 leydig cell line

Aflatoxins B1 (AFB1) a dangerous type of aflatoxin, poses a serious threat to human health. Meanwhile, Taraxasterol, a bioactive compound in dandelion, exhibits strong anti-inflammatory and antioxidant activity. Therefore, the aim of this study was to investigate the impact of AFB1 on the intrinsic and extrinsic pathways of apoptosis, as well as evaluate the protective role of taraxasterol in the TM3 Leydig cell line. Cell viability was evaluated using an MTT assay, measuring the effects of 3.6 µM AFB1 and varying concentrations of taraxasterol. Expression levels of Caspase 3,8, and 9 were analyzed with RT-qPCR, and flow cytometry was used to assess cell cycle progression and apoptotic alterations. The findings of this study demonstrated that exposure to 3.6 µM of AFB1 resulted in an upregulation of Caspase 3 and Caspase 9 expression, indicating an activation of apoptotic pathways in TM3 cells. Additionally, the analysis of apoptosis revealed a significant increase in cellular apoptosis at this AFB1 concentration. However, when TM3 cells were exposed to 5 µM of taraxasterol, a downregulation of Caspase 3 and Caspase 9 expression was observed, suggesting a protective effect against apoptosis. Moreover, the apoptotic rate in TM3 cells was reduced in the presence of 5 µM of taraxasterol. Consequently, this study highlights the potential of taraxasterol as a protective agent against AFB1-induced apoptosis and suggest its potential application in regulating cell survival and apoptosis-related processes. Further investigations are necessary to elucidate the underlying mechanisms and evaluate the clinical implications of taraxasterol in the context of fertility disorders and other conditions associated with AFB1 exposure.

Effects of aflatoxin and fumonisin on gene expression of growth factors and inflammation-related genes in a human hepatocyte cell line

Aflatoxin B1 (AFB1) and fumonisin B1 (FB1) are mycotoxins widely distributed in maize and maized-based products, often occurring together. The implications of co-exposure to aflatoxin and fumonsin for human health are numerous, but a particular concern is the potential of FB1 to modulate AFB1 hepatotoxicity. This study evaluated the toxicity of these mycotoxins, alone or combined, in a human non-tumorigenic liver cell line, HHL-16 cells, and assessed the effects of AFB1 and FB1 on expression of genes involved in immune and growth factor pathways. The results demonstrated that in HHL-16 cells, both AFB1 and FB1 had dose-dependent and time-dependent toxicity, and the combination of them showed a synergistic toxicity in the cells. Moreover, AFB1 caused upregulation of IL6, CCL20, and BMP2, and downregulation of NDP. In combination of AFB1 with FB1, gene expression levels of IL6 and BMP2 were significantly higher compared to individual FB1 treatment, and had a tendency to be higher than individual AFB1 treatment. This study shows that FB1 may increase the hepatoxicity of AFB1 through increasing the inflammatory response and disrupting cell growth pathways.

Cell cycle and enzymatic activity alterations induced by ROS production in human neuroblastoma cells SH-SY5Y exposed to Fumonisin B1, Ochratoxin A and their combination

The presence of mycotoxins such as Fumonisin B1(FB1) and Ochratoxin A (OTA) in food and feed has become a threat to human and animal health since they can produce several afflictions. Different mechanisms of action by which they exercise their cytotoxic activity have been attributed to them, including the production of reactive oxygen species (ROS). For this reason, a measurement of the production of ROS species, and an evaluation of the intrinsic cell enzymatic antioxidant activity, including glutathione peroxidase (GPx), glutathione transferase (GTS), and catalase (CAT) together with a cytotoxicity and cell cycle assay have been performed in undifferentiated SH-SY5Y cells exposed to FB1, OTA and [FB1 + OTA] after 24 h and 48 h. FB1 and OTA. Monitoring of intracellular ROS production was carried out by the H2-DCFDA probe; while spectrometry analysis of absorbances was used for measuring GPx, GST and CAT activity. Finally, cell proliferation and cell cycle distribution were studied by flow cytometry. When cells were treated with OTA, an increase in GPx and GST activity was observed compared to FB1 and [FB1 + OTA]; conversely, a decrease in CAT activity was observed when cells were exposed to OTA coinciding with the results observed for ROS measurement. Regarding the cell cycle, when cells were exposed to OTA, a decrease in G0/G1 was detected, revealing an arrest of cell division for SH-SY5Y cells at the concentrations studied.

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.

New insights into the combined toxicity of aflatoxin B1 and fumonisin B1 in HepG2 cells using Seahorse respirometry analysis and RNA transcriptome sequencing

Aflatoxin B1 (AFB1) and fumonisin B1 (FB1) are widely (co-)detected in food and known for their hepatotoxicity in humans. Still, their combined toxicity needs to be investigated, especially the impact on mitochondria. In our previous work, we examined the effect of short-term exposure to different doses of AFB1, FB1, and their binary mixture (MIX) on the bioenergetic status of HepG2 cells, a well-recognized in vitro model system for studying liver cell function. In the current work, we further investigated the (combined) effect of AFB1 and FB1 on the mitochondrial and glycolytic activity of HepG2 cells using Seahorse respirometry analysis and RNA transcriptome sequencing. The results showed that the co-exposure, especially at high doses, is more toxic due to a more inhibition of all parameters of mitochondrial respiration. However, FB1 contributes more to the MIX effects than AFB1. RNA transcriptome sequencing showed that the p53 signaling pathway, a major orchestrator of mitochondrial apoptosis, was differentially expressed. Moreover, the co-exposure significantly downregulated the genes encoding for Complexes I, II, III, and IV, representing the onset of the suppressed mitochondrial respiration in HepG2 cells.

Preparation and identification of anti-breast cancer cells peptides released from yak milk casein

Yak milk casein (YMC) is the main protein in the yak milk. Peptides released from Yak milk casein (YMC) have multiple bioactivities, including anti-inflammation and immune-regulation, suggesting that these peptides might be able to inhibit cancer theoretically. However, the anti-cancer peptides from YMC have only been sparsely studied. Breast carcinoma is the most common carcinoma in women worldwide. Thus, the paper herein was to identify yak milk casein (YMC)-derived anti-breast cancer peptides via gel filtration, reversed phase high-performance liquid chromatography (RP-HPLC) and liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI MS/MS) for the first time. The inhibitory effects of the hydrolysates on the cell viabilities, cell cycles and apoptosis of breast cancer cells were evaluated with a cck8 kit and a flow cytometry. The result showed that YMC hydrolysates (YMCH) obtained by united hydrolyzation with trypsin (3 h) and alkaline protease (3 h) displayed the highest cell viability inhibition rate for MCF7 (20.74 ± 1.39%) and MDA-MB-231 (26.73 ± 2.87%) cells. Three peptides were identified in the RP-HPLC subfraction F3-4, and a nonapeptide (TPVVVPPFL) showed the most potent inhibitory effects on both cancer cells and displayed good gastrointestinal stability. TPVVVPPFL could induce G2-M cell cycle arrest in MCF7 cells and S cell arrest in MDA-MB-231 cells and induce apoptosis in both cancer cells. Moreover, in silico analysis indicated that the peptide had non-toxic and no inhibitory roles on P4502D6-enzyme. Together, this study shows that YMC is a good source of anti-breast cancer cells peptides.

Bioenergetic Status of the Intestinal and Hepatic Cells after Short Term Exposure to Fumonisin B1 and Aflatoxin B1

Fumonisin B1 (FB1) and aflatoxin B1 (AFB1) are frequent contaminants of staple foods such as maize. Oral exposure to these toxins poses health hazards by disrupting cellular signaling. However, little is known regarding the multifaced mitochondrial dysfunction-linked toxicity of FB1 and AFB1. Here, we show that after exposure to FB1 and AFB1, mitochondrial respiration significantly decreased by measuring the oxygen consumption rate (OCR), mitochondrial membrane potential (MMP) and reactive oxygen species (ROS). The current work shows that the integrity of mitochondria (MMP and ROS), that is the central component of cell apoptosis, is disrupted by FB1 and AFB1 in undifferentiated Caco-2 and HepG2 cells as in vitro models for human intestine and liver, respectively. It hypothesizes that FB1 and AFB1 could disrupt the mitochondrial electron transport chain (ETC) to induce mitochondrial dysfunction and break the balance of transferring H⁺ between the mitochondrial inner membrane and mitochondrial matrix, however, the proton leak is not increasing and, as a result, ATP synthesis is blocked. At the sub-toxic exposure of 1.0 µg/mL for 24 h, i.e., a viability of 95% in Caco-2 and HepG2 cells, the mitochondrial respiration was, however, stimulated. This suggests that the treated cells could reserve energy for mitochondrial respiration with the exposure of FB1 and AFB1, which could be a survival advantage.

In vitro and in vivo evaluation of AFB1 and OTA-toxicity through immunofluorescence and flow cytometry techniques: A systematic review

Due to the globalization, mycotoxins have been considered a major risk to human health being the main contaminants of foodstuffs. Among them, AFB1 and OTA are the most toxic and studied. Therefore, the goal of this review is to deepen the knowledge about the toxicological effects that AFB1 and OTA can induce on human health by using flow cytometry and immunofluorescence techniques in vitro and in vivo models. The examination of the selected reports shows that the majority of them are focused on immunotoxicity while the rest are concerned about nephrotoxicity, hepatotoxicity, gastrointestinal toxicity, neurotoxicity, embryotoxicity, reproductive system, breast, esophageal and lung toxicity. In relation to immunofluorescence analysis, biological processes related to AFB1- and OTA-toxicity were evaluated such as inflammation, neuronal differentiation, DNA damage, oxidative stress and cell death. In flow cytometry analysis, a wide range of assays have been performed across the reviewed studies being apoptosis assay, cell cycle analysis and intracellular ROS measurement the most employed. Although, the toxic effects of AFB1 and OTA have been reported, further research is needed to clarify AFB1 and OTA-mechanism of action on human health.

Combinational inhibitory action of essential oils and gamma irradiation for controlling Aspergillus flavus and Aspergillus parasiticus growth and their aflatoxins biosynthesis in vitro and in situ conditions

The purpose of this study was to investigate the effects of certain essential oils (star anise, lemon leaves, marjoram, fennel, and lavender) on the fungal growth of Aspergillus flavus and Aspergillus parasiticus and their production of aflatoxin B1 (AFB1). The degree of suppression of the aflatoxigenic strains' growth and their production of AFB1 is mainly affected by the kind and the concentration of the tested essential oils (EOs). Star anise essential oil had the lowest minimum inhibitory concentration (0.5 and 1.0 μL/mL) against A. flavus and A. parasiticus, respectively, so it was the best among the five different oils. The study of liquid chromatography with tandem mass spectrometry revealed that star anise EO resulted in a 98% reduction in AFB1 without a breakdown of AFB1 products after treatment thus the complete removal of AFB1 was done without any toxic residues. The combination showed a synergistic effect, the combinational treatment between γ-irradiation at a low dose (2 kGy) and star anise EO at concentrate 0.5 μL/g destroyed A. flavus and A. parasiticus inoculated (individually) in sorghum and peanut, respectively throughout the storage period (8 weeks).

Assessing the Effect of Mycotoxin Combinations: Which Mathematical Model Is (the Most) Appropriate?

In the past decades, many studies have examined the nature of the interaction between mycotoxins in biological models classifying interaction effects as antagonisms, additive effects, or synergisms based on a comparison of the observed effect with the expected effect of combination. Among several described mathematical models, the arithmetic definition of additivity and factorial analysis of variance were the most commonly used in mycotoxicology. These models are incorrectly based on the assumption that mycotoxin dose-effect curves are linear. More appropriate mathematical models for assessing mycotoxin interactions include Bliss independence, Loewe’s additivity law, combination index, and isobologram analysis, Chou-Talalays median-effect approach, response surface, code for the identification of synergism numerically efficient (CISNE) and MixLow method. However, it seems that neither model is ideal. This review discusses the advantages and disadvantages of these mathematical models.

Deoxynivalenol, but not fumonisin B1, aflatoxin B1 or diesel exhaust particles disrupt integrity of the horse's respiratory epithelium and predispose it for equine herpesvirus type 1 infection

The horse's respiratory tract daily encounters a plethora of respirable hazards including air pollutants, mycotoxins and airborne pathogens. To date, the precise effect of air pollution and mycotoxins on respiratory epithelial integrity and subsequent pathogen invasion in the horse has not been studied. Here, diesel exhaust particles (DEP) and three major mycotoxins (deoxynivalenol [DON], aflatoxin B1 [AFB1] and fumonisin B1 [FB1]) were applied to the apical surfaces of both ex vivo respiratory mucosal explants and in vitro primary equine respiratory epithelial cells (EREC) cultivated at the air-liquid interface, prior to inoculation with equine herpesvirus type 1 (EHV1). DON, but not AFB1, FB1 and DEP affected epithelial integrity in both ex vivo and in vitro systems, as demonstrated by histological changes in respiratory epithelial morphology and a drop in transepithelial electrical resistance across the EREC monolayer. Further, DON-pretreated explants showed on average 6.5 ± 4.5-fold more EHV1 plaques and produced on average 1 log₁₀ more extracellular virus particles compared to control diluent- and FB1-pretreated respiratory mucosal explants. Similarly, EHV1 infection was greatly enhanced in EREC upon pretreatment with DON. Based on our findings, we propose that inhalation of DON predisposes horses for EHV1 infection by affecting respiratory epithelial integrity.

Copper or Manganese Supplementation Endows the Peptic Hydrolysate from Bovine Lactoferrin with Enhanced Activity to Human Gastric Cancer AGS Cells

A lactoferrin hydrolysate (LFH) was generated from bovine lactoferrin by pepsin, mixed with Cu²⁺ and Mn²⁺ at 0.64-1.28 and 0.28-0.56 mg/g protein, respectively; and then their in vitro effects on human gastric cancer AGS cells were assessed. With incubation times of 24 or 48 h, LFH and its Cu²⁺/Mn²⁺ mixtures at 10-30 mg/mL in dose-dependent manner inhibited cell growth; and more, these mixtures showed higher activities than LFH alone. Cell treatments of LFH and the mixtures (25 mg/mL) for 24 h could arrest cell cycle at G0/G1-phase, damage mitochondrial membrane integrity, and induce apoptosis, while the mixtures were also more powerful than LFH to exert these three effects. Higher Cu²⁺/Mn²⁺ supplementation level resulted in higher growth inhibition, cell cycle arrest, mitochondrial membrane potential disruption, and apoptosis induction; furthermore, Mn²⁺ was notable for its higher efficacy than Cu²⁺ to increase these four effects. Western-blot assay results revealed that four apoptosis-related proteins Bad, Bax, cytochrome c, and p53 were up-regulated, and both caspase-3 and caspase-9 also were cleaved and activated; moreover, two autophagy-related proteins LC3-II and cleaved Beclin-1 were down- and up-regulated, respectively. It is thus concluded that Cu²⁺ and especially Mn²⁺ could endow supplemented LFH with increased anti-cancer effects in AGS cells, with two proposed events as enhanced apoptosis induction (via activating apoptosis-related proteins) and autophagy inhibition (via activating autophagy-related proteins).

Probiotic Bacillus subtilis CW14 reduces disruption of the epithelial barrier and toxicity of ochratoxin A to Caco-2 cells

The multiple toxic effects of ochratoxin A (OTA) are a threat for human and animal. This study aimed to examine whether B. subtilis CW14 protected against OTA-induced barrier disruption and cell damage to Caco-2 cells. The results showed that Caco-2 cells treated with OTA led to microvilli disruption, tight junction protein (ZO-1 and claudin-1) damage, and inhibition of cell proliferation by arresting the cell cycle in the G2/M phase that promoted apoptosis. The treatment of B. subtilis CW14 mitigated the tight junction injury by improving ZO-1 protein expression, and it reduced apoptosis that was induced by OTA. Furthermore, transcriptome analysis indicated that OTA down-regulated genes that involved in the tight junction, cell cycle, and apoptosis-related signaling pathways. B. subtilis CW14 may have protected the ZO-1 protein by activating the toll-like receptor signaling pathway, and it reduced OTA damage by down-regulating the death receptor genes and up-regulating the DNA repair genes. These findings demonstrated the importance of B. subtilis CW14 in the regulation of tight junction proteins and in reducing death of intestinal epithelial cells. Thus, B. subtilis CW14 is a potential candidate as a food additive to protect against intestinal damage.

Combinational Inhibitory Action of Hedychium spicatum L. Essential Oil and γ-Radiation on Growth Rate and Mycotoxins Content of Fusarium graminearum in Maize: Response Surface Methodology

Nowadays, contamination of agricultural commodities with fungi and their mycotoxins is one of the most annoying with regard to food safety and pose serious health risk. Therefore, there is a requisite to propose suitable mitigation strategies to reduce the contamination of fungi and mycotoxins in agricultural commodities. In the present study, combinational inhibitory effect of Hedychium spicatum L. essential oil (HSEO) and radiation was established on growth rate, production of deoxynivalenol (DON) and zearalenone (ZEA) by Fusarium graminearum in maize grains. The HSEO was obtained from rhizomes by hydrodistillation technique and chemical composition was revealed by GC-MS analysis. A total of 48 compounds were identified and major compounds were 1,8-cineole (23.15%), linalool (12.82%), and β-pinene (10.06%). The discrete treatments of HSEO and radiation were effective in reducing the fungal growth rate and mycotoxins content, and the complete reduction was noticed at 3.15 mg/g of HSEO and 6 kGy of radiation. Response surface methodology (RSM) was applied to evaluate the combinational inhibitory effect of HSEO and radiation treatments on fungal growth rate and mycotoxins content. A total of 13 experiments were designed with distinct doses of HSEO and radiation by central composite design (CCD) of Stat-Ease Design-Expert software. In combinational approach, complete reductions of fungal growth, DON, and ZEA content were noticed at 1.89 mg/g of HSEO and 4.12 kGy of radiation treatments. The optimized design concluded that combinational treatments of HSEO and radiation were much more effective in reducing the fungal growth and mycotoxins content compared to their discrete treatments (p < 0.05). Responses of the design were assessed by second-order polynomial regression analysis and found that quadratic model was well fitted. The optimized design has larger F-value and adequate precision, smaller p-value, decent regression coefficients (R² ) and found statistically significant (p < 0.05). In addition, correlation matrix, normal plot residuals, Box-Cox, and actual vs. predicted plots were endorsed that optimized design was accurate and appropriate. The proposed combinational decontamination technique could be highly applicable in agriculture and food industry to safeguard the food and feed products from fungi and mycotoxins.