Gene expression profile and toxic effects in human bronchial epithelial cells exposed to zearalenone

Endocrine Effect of Some Mycotoxins on Humans: A Clinical Review of the Ways to Mitigate the Action of Mycotoxins

Fungi such as Aspergillus spp. and Fusarium spp., which are commonly found in the environment, pose a serious global health problem. This study aims to present the results of epidemiological studies, including clinical cases, on the relationship between human exposure to some mycotoxins, especially zearalenone and aflatoxin, and the occurrence of reproductive disorders. In addition, examples of methods to reduce human exposure to mycotoxins are presented. In March 2023, various databases (PubMed, Google Scholar, EMBASE and Web of Science) were systematically searched using Google Chrome to identify studies evaluating the association between exposure to mycotoxins and the occurrence of complications related to impaired fertility or cancer incidence. The analysed data indicate that exposure to the evaluated mycotoxins is widespread and correlates strongly with precocious puberty, reduced fertility and increased cancer incidence in women and men worldwide. There is evidence to suggest that exposure to the Aspergillus mycotoxin aflatoxin (AF) during pregnancy can impair intrauterine foetal growth, promote neonatal jaundice and cause perinatal death and preterm birth. In contrast, exposure to the Fusarium mycotoxin zearalenone (ZEA) leads to precocious sexual development, infertility, the development of malformations and the development of breast cancer. Unfortunately, the development of methods (biological, chemical or physical) to completely eliminate exposure to mycotoxins has limited practical application. The threat to human health from mycotoxins is real and further research is needed to improve our knowledge and specific public health interventions.

Comparative Analysis of Transcriptomic Changes including mRNA and microRNA Expression Induced by the Xenoestrogens Zearalenone and Bisphenol A in Human Ovarian Cells

Xenoestrogens are natural or synthetic compounds that mimic the effect of endogenous estrogens and might cause cancer. We aimed to compare the global transcriptomic response to zearalenone (ZEA; mycotoxin) and bisphenol A (BPA; plastic additive) with the effect of physiological estradiol (E2) in the PEO1 human ovarian cell line by mRNA and microRNA sequencing. Estrogen exposure induced remarkable transcriptomic changes: 308, 288 and 63 genes were upregulated (log₂FC > 1); 292, 260 and 45 genes were downregulated (log₂FC < -1) in response to E2 (10 nM), ZEA (10 nM) and BPA (100 nM), respectively. Furthermore, the expression of 13, 11 and 10 miRNAs changed significantly (log₂FC > 1, or log₂FC < -1) after exposure to E2, ZEA and BPA, respectively. Functional enrichment analysis of the significantly differentially expressed genes and miRNAs revealed several pathways related to the regulation of cell proliferation and migration. The effect of E2 and ZEA was highly comparable: 407 genes were coregulated by these molecules. We could identify 83 genes that were regulated by all three treatments that might have a significant role in the estrogen response of ovarian cells. Furthermore, the downregulation of several miRNAs (miR-501-5p, let-7a-2-3p, miR-26a-2-3p, miR-197-5p and miR-582-3p) was confirmed by qPCR, which might support the proliferative effect of estrogens in ovarian cells.

Zearalenone induces apoptosis and autophagy by regulating endoplasmic reticulum stress signalling in porcine trophectoderm cells

Zearalenone (ZEA), a mycotoxin produced mainly by fungi belonging to Fusarium species in foods and feeds, causes a serious hazard to humans and animals. Numerous studies have revealed that ingesting ZEA can disrupt the reproductive function and impair the reproductive process in animals. This experiment was to investigate the toxicological effect and the mechanism of ZEA exposure on reproduction in pigs during early stages of pregnancy. In the present study, we treated with 0 to 80 μmol/L ZEA for 12 or 24 h in trophoblast ectoderm (pTr) cells. The results showed that ZEA had significantly decreased cell proliferation (P < 0.05), which was accompanied by DNA damage-related cell cycle arrest at G2/M phase, activation of the apoptosis and endoplasmic reticulum (ER) stress, as well as impairment of barrier function (P < 0.05). Western blot analysis and transmission electron microscopy (TEM) showed that exposure to ZEA can activation of autophagy in pTr cells. Importantly, pretreatment with chloroquine (CQ) or 3-methyladenine (3-MA) led to increased apoptosis in pTr cells. Interestingly, pTr cells pretreated with 4-phenylbutyric acid (4-PBA), an inhibitor of ER stress, resulted in reduced cell death in pTr cells, indicating a critical role for ER stress in the activation of autophagy. In conclusion, these results reveal that ZEA-triggered ER stress is critical for the cell fate decision of pTr cells during early porcine embryonic development. Application of small molecules with ability of blocking ER stress might be therapeutic option to reduce the deleterious effect of ZEA in pregnant animals.

Zearalenone Promotes LPS-Induced Oxidative Stress, Endoplasmic Reticulum Stress, and Accelerates Bovine Mammary Epithelial Cell Apoptosis

Both zearalenone (ZEA) and lipopolysaccharide (LPS) can induce oxidative stress, and even apoptosis in bovine mammary epithelial cells (MAC-T), but not much attention has been given to the synergistic effect of ZEA and LPS. In this study, we treated MAC-T cells with different concentrations of LPS (1, 10, 50, and 100 μg/mL) and ZEA (5, 15, and 30 μM) to induce cell damage. Previous results show that MAC-T cell viability decreases with increasing LPS concentration. Meanwhile, 1 µg/mL LPS and ZEA were selected for combined treatment in subsequent studies. It was found that co-treatment with ZEA and LPS increases the accumulation of reactive oxygen species (ROS) and malondialdehyde (MDA), decreases mitochondrial membrane potential (MMP), and superoxide dismutase (SOD), and reduces glutathione (GSH). ZEA and LPS are found to activate endoplasmic reticulum (ER) stress by increasing the expression of glucose-regulated protein 78 kDa (GRP78), activating transcription factor 6 (ATF6) and C/EBP homologous protein (CHOP). It increases cell apoptosis by suppressing the expression of the anti-apoptotic protein B-cell lymphoma-2 (Bcl-2), indicated by up-regulation of Bcl2-associated X protein (Bax) and Cysteinyl aspartate-specific proteinases 3 (caspase-3) expression. The above results suggest that the synergistic effect of ZEA and LPS aggravate cytotoxicity.

Cytosine Methylation in Genomic DNA and Characterization of DNA Methylases and Demethylases and Their Expression Profiles in Viroid-Infected Hop Plants (Humulus lupulus Var. 'Celeia')

Abiotic and biotic stresses can lead to changes in host DNA methylation, which in plants is also mediated by an RNA-directed DNA methylation mechanism. Infections with viroids have been shown to affect DNA methylation dynamics in different plant hosts. The aim of our research was to determine the content of 5-methylcytosine (5-mC) in genomic DNA at the whole genome level of hop plants (Humulus lupulus Var. 'Celeia') infected with different viroids and their combinations and to analyse the expression of the selected genes to improve our understanding of DNA methylation dynamics in plant-viroid systems. The adapted HPLC-UV method used proved to be suitable for this purpose, and thus we were able to estimate for the first time that the cytosine methylation level in viroid-free hop plants was 26.7%. Interestingly, the observed 5-mC level was the lowest in hop plants infected simultaneously with CBCVd, HLVd and HSVd (23.7%), whereas the highest level was observed in plants infected with HLVd (31.4%). In addition, we identified three DNA methylases and one DNA demethylase gene in the hop's draft genome. The RT-qPCR revealed upregulation of all newly identified genes in hop plants infected with all three viroids, while no altered expression was observed in any of the other hop plants tested, except for CBCVd-infected hop plants, in which one DNA methylase was also upregulated.

Oxidative stress as a plausible mechanism for zearalenone to induce genome toxicity

Zearalenone (ZEN), a common non-steroidal estrogenic mycotoxin of the Fusarium genus, is one of the most frequent and powerful contaminant of grains and cereal products representing a serious threat for people and livestock health. In fact, ZEN causes cytotoxicity and genotoxicity in a variety of cell types at least in part through binding to estrogen receptors (ERs). The main pathways through which ZEN induces such effects remain, however, elusive. In particular, how the mycotoxin causes DNA damage, dysregulates DNA repair mechanisms, changes epigenome of targeted cells and, not least, affects chromatin conformation and non-coding RNA (ncRNA), is unclear. In the present paper, following extensive review of the literature about such ZEN effects and our own experience in studying the effects of this compound on reproductive processes, we propose that increased production of reactive oxygen species (ROS) and consequently oxidative stress (OS) are central in ZEN genotoxicity. Besides to shed light on the action mechanisms of the mycotoxin, this notion might help to develop effective strategies to counteract its deleterious biological effects.

Brain-Targeted Intranasal Delivery of Zotepine Microemulsion: Pharmacokinetics and Pharmacodynamics

The purpose of our study was to improve the solubility, bioavailability, and efficacy of zotepine (ZTP) by brain-targeted intranasal delivery of microemulsion (ME) and its physicochemical properties, the pharmacokinetic and pharmacodynamic parameters were evaluated. The optimized ME formulations contain 10% w/w of oil (Capmul MCM C8, monoglycerides, and diglycerides of caprylic acid), 50% w/w of Smix (Labrasol and Transcutol HP, and 40% w/w of water resulting in a globule size of 124.6 ±3.52 nm with low polydispersity index (PDI) (0.212 ± 0.013) and 2.8-fold higher permeation coefficient through porcine nasal mucosa compared to pure drug. In vitro cell line studies on RPMI 2650, Beas-2B, and Neuro-2A revealed ZTP-ME as safe. ZTP-ME administered intranasally showed higher AUC0-t24 (18.63 ± 1.33 h x µg/g) in the brain by approximately 4.3-fold than oral ME (4.30 ± 0.92 h × µg/g) and 7.7-fold than intravenous drug solutions (2.40 ± 0.36 h × µg/g). In vivo anti-schizophrenic activity was conducted using catalepsy test scores, the formulation showed better efficacy via the intranasal route; furthermore, there was no inflammation or hemorrhage in the nasal cavity. The results concluded that the ZTP microemulsion as a safe and effective strategy could greatly enhance brain distribution by intranasal administration.

Impaired primordial follicle assembly in offspring ovaries from zearalenone-exposed mothers involves reduced mitochondrial activity and altered epigenetics in oocytes

Previous works have shown that zearalenone (ZEA), as an estrogenic pollutant, has adverse effects on mammalian folliculogenesis. In the present study, we found that prolonged exposure of female mice to ZEA around the end of pregnancy caused severe impairment of primordial follicle formation in the ovaries of newborn mice and altered the expression of many genes in oocytes as revealed by single-cell RNA sequencing (scRNA-seq). These changes were associated with morphological and molecular alterations of mitochondria, increased autophagic markers in oocytes, and epigenetic changes in the ovaries of newborn mice from ZEA-exposed mothers. The latter increased expression of HDAC2 deacetylases was leading to decreased levels of H3K9ac and H4K12ac. Most of these modifications were relieved when the expression of  Hdac2 in newborn ovaries was reduced by RNA interference during in vitro culture in the presence of ZEA. Such changes were also alleviated in offspring ovaries from mothers treated with both ZEA and the coenzyme Q10 (CoQ10), which is known to be able to restore mitochondrial activities. We concluded that impaired mitochondrial activities in oocytes caused by ZEA are at the origin of metabolic alterations that modify the expression of genes controlling autophagy and primordial follicle assembly through changes in epigenetic histones.

Multidimensional analysis of the epigenetic alterations in toxicities induced by mycotoxins

Mycotoxins contaminate all types of food and feed, threatening human and animal health through food chain accumulation, producing various toxic effects. Increasing attention is being focused on the molecular mechanism of mycotoxin-induced toxicity in all kinds of in vivo and in vitro models. Epigenetic alterations, including DNA methylation, non-coding RNAs (ncRNAs), and protein post-translational modifications (PTMs), were identified as being involved in various types of mycotoxin-induced toxicity. In this review, the emphasis was on summarizing the epigenetic alterations induced by mycotoxin, including aflatoxin B1 (AFB1), ochratoxin A (OTA), zearalenone (ZEA), fumonisin B1 (FB1), and deoxynivalenol (DON). This review summarized and analyzed the roles of DNA methylation, ncRNAs, and protein PTMs after mycotoxin exposure based on recently published papers. Moreover, the main research methods and their deficiencies were determined, while some remedial suggestions are proposed. In summary, this review helps to understand better the epigenetic alterations induced by the non-genotoxic effects of mycotoxin.

Methylenetetrahydrofolate reductase gene polymorphism, global DNA methylation and blood pressure: a population based study from North India

BACKGROUND

Hypertension is a complex disorder affected by gene-environment interactions. Methylenetetrahydrofolate reductase (MTHFR) gene is one of the genes in One Carbon Metabolic (OCM) pathway that affects both blood pressure and epigenetic phenomenon. MTHFR C677T gene polymorphism leads to reduced methylation capacity via increased homocysteine concentrations. Global DNA methylation (5mC%) also gets affected in conditions such as hypertension. However, no study is found to understand hypertension in terms of both genetics and epigenetics. The present study aims to understand the relation between methylation, MTHFR C677T gene polymorphism and hypertension. It also tries to understand relation (if any) between methylation and anti-hypertensive drugs.

METHODS

This is a cross-sectional study where data were collected from a total of 1634 individuals of either sex in age group 35-65 years. Hypertensives (SBP ≥ 140 mm Hg and DBP ≥ 90 mm Hg) (on treatment/not on treatment) and absolute controls were 236 (cases) and 307 (controls), respectively. All the samples were subjected to MTHFR C677T gene polymorphism screening (PCR-RFLP) and global DNA methylation assay (ELISA based colorimetric assay). Results of both the analyses were obtained on 218 cases, 263 controls.

RESULTS

Median 5mC% was relatively lower among cases (p > 0.05) compared to controls, despite controlling for confounders (age, sex, smoking, alcohol, diet) (r2-0.92, p-0.08). Cases not on medication had significantly reduced 5mC% compared to controls (p < 0.05), despite adjusting for confounders (r2-0.857, p-0.01). Among cases (irrespective of treatment), there was a significant variation in 5mC% across the three genotypes i.e. CC, CT and TT, with no such variation among controls. Cases (not on medication) with TT genotype had significantly lower methylation levels compared to the TT genotype controls and cases (on medication) (p < 0.01).

CONCLUSION

Global DNA hypomethylation seems to be associated with hypertension and antihypertensive drugs seem to improve methylation. Hypertensive individuals with TT genotype but not on medication are more likely to be prone to global DNA hypomethylation. Important precursors in OCM pathway include micronutrients such as vitamin B-12, B-9 and B-6; their nutritional interventions (either dietary or supplement) may serve as strategies to prevent hypertension at population level. However, more epidemiological-longitudinal studies are needed for further validation.

Fusaric acid decreases p53 expression by altering promoter methylation and m6A RNA methylation in human hepatocellular carcinoma (HepG2) cells

Fusaric acid (FA) is a food-borne mycotoxin that mediates toxicity with limited information on its epigenetic properties. p53 is a tumour suppressor protein that regulates cell cycle arrest and apoptotic cell death. The expression of p53 is regulated transcriptionally by promoter methylation and post-transcriptionally by N-6-methyladenosine (m6A) RNA methylation. We investigated the effect of FA on p53 expression and its epigenetic regulation via promoter methylation and m6A RNA methylation in human hepatocellular carcinoma (HepG2) cells. HepG2 cells were treated with FA [0, 25, 50, 104, and 150 µg/ml; 24 h] and thereafter, DNA, RNA, and protein was isolated. Promoter methylation and expression of p53 was measured using qPCR and Western blot. RNA immuno-precipitation was used to determine m6A-p53 levels. The expression of m6A methyltransferases (METTL3 and METTL14), demethylases (FTO and ALKBH5), and readers (YTHDF1-3 and YTHDC2) were measured using qPCR. FA induced p53 promoter hypermethylation (p < 0.0001) and decreased p53 expression (p < 0.0001). FA decreased m6A-p53 levels (p < 0.0001) by decreasing METTL3 (p < 0.0001) and METTL14 (p < 0.0001); and suppressed expression of YTHDF1 (p < 0.0001), YTHDF3 (p < 0.0001), and YTHDC2 (p < 0.0001) that ultimately reduced p53 translation (p < 0.0001). Taken together, the data shows that FA epigenetically decreased p53 expression by altering its promoter methylation and m6A RNA methylation in HepG2 cells. This study reveals a mechanism for p53 regulation by FA and provides insight into future therapeutic interventions.

The Impact of Natural Dietary Compounds and Food-Borne Mycotoxins on DNA Methylation and Cancer

Cancer initiation and progression is an accumulation of genetic and epigenetic modifications. DNA methylation is a common epigenetic modification that regulates gene expression, and aberrant DNA methylation patterns are considered a hallmark of cancer. The human diet is a source of micronutrients, bioactive molecules, and mycotoxins that have the ability to alter DNA methylation patterns and are thus a contributing factor for both the prevention and onset of cancer. Micronutrients such as betaine, choline, folate, and methionine serve as cofactors or methyl donors for one-carbon metabolism and other DNA methylation reactions. Dietary bioactive compounds such as curcumin, epigallocatechin-3-gallate, genistein, quercetin, resveratrol, and sulforaphane reactivate essential tumor suppressor genes by reversing aberrant DNA methylation patterns, and therefore, they have shown potential against various cancers. In contrast, fungi-contaminated agricultural foods are a source of potent mycotoxins that induce carcinogenesis. In this review, we summarize the existing literature on dietary micronutrients, bioactive compounds, and food-borne mycotoxins that affect DNA methylation patterns and identify their potential in the onset and treatment of cancer.

Fusaric acid-induced epigenetic modulation of hepatic H3K9me3 triggers apoptosis in vitro and in vivo

Aim: To determine the effect of the food-borne mycotoxin, fusaric acid (FA) on miR-200a, SUV39H1-mediated H3K9me3, genome integrity and apoptosis in human liver (HepG2) cells and C57BL/6 mice livers. Materials & methods: MiR-200a, Sirt1, SUV39H1-mediated H3K9me3, genome integrity and apoptosis was measured in HepG2 cells and C57BL/6 mice livers using qPCR, western blot, DNA electrophoresis and luminometry. Results: FA: upregulated miR-200a and decreased Sirt1 expression in HepG2 cells and mice livers; decreased expression of SUV39H1 and KDM4B, thus decreasing H3K9me3 and increasing H3K9me1; increased cell mortality via apoptosis. Conclusion: FA induced apoptosis by upregulating miR-200a and decreasing SUV39H1-mediated H3K9me3 in HepG2 cells and mice livers.

IGSF3 mutation identified in patient with severe COPD alters cell function and motility

Cigarette smoking (CS) and genetic susceptibility determine the risk for development, progression, and severity of chronic obstructive pulmonary diseases (COPD). We posited that an incidental balanced reciprocal chromosomal translocation was linked to a patient's risk of severe COPD. We determined that 46,XX,t(1;4)(p13.1;q34.3) caused a breakpoint in the immunoglobulin superfamily member 3 (IGSF3) gene, with markedly decreased expression. Examination of COPDGene cohort identified 14 IGSF3 SNPs, of which rs1414272 and rs12066192 were directly and rs6703791 inversely associated with COPD severity, including COPD exacerbations. We confirmed that IGSF3 is a tetraspanin-interacting protein that colocalized with CD9 and integrin B1 in tetraspanin-enriched domains. IGSF3-deficient patient-derived lymphoblastoids exhibited multiple alterations in gene expression, especially in the unfolded protein response and ceramide pathways. IGSF3-deficient lymphoblastoids had high ceramide and sphingosine-1 phosphate but low glycosphingolipids and ganglioside levels, and they were less apoptotic and more adherent, with marked changes in multiple TNFRSF molecules. Similarly, IGSF3 knockdown increased ceramide in lung structural cells, rendering them more adherent, with impaired wound repair and weakened barrier function. These findings suggest that, by maintaining sphingolipid and membrane receptor homeostasis, IGSF3 is required for cell mobility-mediated lung injury repair. IGSF3 deficiency may increase susceptibility to CS-induced lung injury in COPD.

Zearalenone induces NLRP3-dependent pyroptosis via activation of NF-κB modulated by autophagy in INS-1 cells

Zearalenone (ZEA), one of the mycotoxins widely found in food and feed, can stimulate an inflammatory reaction. In the present study, we demonstrated that ZEA induced the activation of NLRP3 inflammasome even pyroptotic cell death in rat Insulinoma Cell Line (INS-1). Meanwhile, according to the results of western blot and TEM, the level of autophagy was elevated by ZEA, which protected against the activation of NLRP3 inflammasome and inflammatory response caused by ZEA. Furthermore, we indicated that ZEA-induced NF-κB p65 activation contributed to the activation of the NLRP3 inflammasome, inflammatory response, and pyroptosis in INS-1 cells, which were indicated by western blot and immunofluorescence, and the activation of NF-κB p65 induced by ZEA was autophagy-dependent. This study demonstrates that ZEA induces NLRP3-dependent pyroptosis via activation of NF-κB modulated by autophagy in INS-1 cells.

Fusaric acid-induced promoter methylation of DNA methyltransferases triggers DNA hypomethylation in human hepatocellular carcinoma (HepG2) cells

Fusaric acid (FA), a mycotoxin contaminant of maize, displays toxicity in plants and animals; however, its epigenetic mechanism is unknown. DNA methylation, an epigenetic modification that regulates gene expression, is mediated by DNA methyltransferases (DNMTs; DNMT1, DNMT3A, and DNMT3B) and demethylases (MBD2). The expression of DNMTs and demethylases are regulated by promoter methylation, microRNAs (miR-29b) and post-translational modifications (ubiquitination). Alterations in these DNA methylation modifying enzymes affect DNA methylation patterns and offer novel mechanisms of FA toxicity. We determined the effect of FA on global DNA methylation as well as a mechanism of FA-induced changes in DNA methylation by transcriptional (promoter methylation), post-transcriptional (miR-29b) and post-translational (ubiquitination) regulation of DNMTs and MBD2 in the human hepatocellular carcinoma (HepG2) cell line. FA induced global DNA hypomethylation (p < 0.0001) in HepG2 cells. FA decreased the mRNA and protein expression of DNMT1 (p < 0.0001), DNMT3A (p < 0.0001), and DNMT3B (p < 0.0001) by upregulating miR-29b (p < 0.0001) and inducing promoter hypermethylation of DNMT1 (p < 0.0001) and DNMT3B (p < 0.0001). FA decreased the ubiquitination of DNMT1 (p = 0.0753), DNMT3A (p = 0.0008), and DNMT3B (p < 0.0001) by decreasing UHRF1 (p < 0.0001) and USP7 (p < 0.0001). FA also induced MBD2 promoter hypomethylation (p < 0.0001) and increased MBD2 expression (p < 0.0001). Together these results indicate that FA induces global DNA hypomethylation by altering DNMT promoter methylation, upregulating miR-29b, and increasing MBD2 in HepG2 cells.

Effects of zearalenone and its derivatives on the synthesis and secretion of mammalian sex steroid hormones: A review

Zearalenone (ZEA), a non-steroidal estrogen mycotoxin produced by several species of Fusarium fungi, can be metabolized into many other derivatives by microorganisms, plants, animals and humans. It can affect mammalian reproductive capability by impacting the synthesis and secretion of sex hormones, including testosterone, estradiol and progesterone. This review summarizes the mechanisms in which ZEA and its derivatives disturb the synthesis and secretion of sex steroid hormones. Because of its structural analogy to estrogen, ZEA and its derivatives can exert a variety of estrogen-like effects and engage in estrogen negative feedback regulation, which can result in mediating the production of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) in the pituitary gland. ZEA and its derivatives can ultimately reduce the number of Leydig cells and granulosa cells by inducing oxidative stress, endoplasmic reticulum (ER) stress, cell cycle arrest, cell apoptosis, and cell regeneration delay. Additionally, they can disrupt the mitochondrial structure and influence mitochondrial functions through overproduction of reactive oxygen species (ROS) and aberrant autophagy signaling ways. Finally, ZEA and its derivatives can disturb the expressions and activities of the related steroidogenic enzymes through cross talking between membrane and nuclear estrogen receptors.

Biomarkers from circulating neutrophil transcriptomes have potential to detect unruptured intracranial aneurysms

BACKGROUND

Intracranial aneurysms (IAs) are dangerous because of their potential to rupture and cause deadly subarachnoid hemorrhages. Previously, we found significant RNA expression differences in circulating neutrophils between patients with unruptured IAs and aneurysm-free controls. Searching for circulating biomarkers for unruptured IAs, we tested the feasibility of developing classification algorithms that use neutrophil RNA expression levels from blood samples to predict the presence of an IA.

METHODS

Neutrophil RNA extracted from blood samples from 40 patients (20 with angiography-confirmed unruptured IA, 20 angiography-confirmed IA-free controls) was subjected to next-generation RNA sequencing to obtain neutrophil transcriptomes. In a randomly-selected training cohort of 30 of the 40 samples (15 with IA, 15 controls), we performed differential expression analysis. Significantly differentially expressed transcripts (false discovery rate < 0.05, fold change ≥ 1.5) were used to construct prediction models for IA using four well-known supervised machine-learning approaches (diagonal linear discriminant analysis, cosine nearest neighbors, nearest shrunken centroids, and support vector machines). These models were tested in a testing cohort of the remaining 10 neutrophil samples from the 40 patients (5 with IA, 5 controls), and model performance was assessed by receiver-operating-characteristic (ROC) curves. Real-time quantitative polymerase chain reaction (PCR) was used to corroborate expression differences of a subset of model transcripts in neutrophil samples from a new, separate validation cohort of 10 patients (5 with IA, 5 controls).

RESULTS

The training cohort yielded 26 highly significantly differentially expressed neutrophil transcripts. Models using these transcripts identified IA patients in the testing cohort with accuracy ranging from 0.60 to 0.90. The best performing model was the diagonal linear discriminant analysis classifier (area under the ROC curve = 0.80 and accuracy = 0.90). Six of seven differentially expressed genes we tested were confirmed by quantitative PCR using isolated neutrophils from the separate validation cohort.

CONCLUSIONS

Our findings demonstrate the potential of machine-learning methods to classify IA cases and create predictive models for unruptured IAs using circulating neutrophil transcriptome data. Future studies are needed to replicate these findings in larger cohorts.

A comparison and column selection of Hydrophilic Interaction Liquid Chromatography and Reversed-Phase High-Performance Liquid Chromatography for detection of DNA methylation

5-methylcytosine (5mC) is an epigenetic mark which has a profound effect on various fundamental processes in cells. In present study, at first Hydrophilic Interaction Liquid Chromatography (HILIC) was compared with Reversed-Phase High-Performance Liquid Chromatography (RP-HPLC) based on their selectivity (α), retention factor (k), and resolution (R) for cytosine (C) and 5mC nucleobases. We tried to justify the separation mechanism on the basis of mobile phase and solute polarity, structural characterization of solute and stationary phases, log Do/w, and pk_a under both modes. Then, these two modes were compared in order to select the best column for measurement of methylation level in two real samples with less analytical complexity (i.e. animal and bacteria) and a highly complex sample (i.e. plant), after chemical hydrolysis of DNA. In this favor, diol and cyano (CN) columns in HILIC mode as well as C₈ and C₁₈ in RP-HPLC were investigated. Optimum separation and the best validation parameters were obtained for CN column with Limit of Detection (LOD) of 1.4 pmol and Limit of Quantification (LOQ) of 4.8 pmol for 5mC. When the CN column was used in HILIC-UV procedure, separation of 5mC and C bases was achieved in all types of hydrolyzed DNA solutions.

Zearalenone Promotes Cell Proliferation or Causes Cell Death?

Zearalenone (ZEA), one of the mycotoxins, exerts different mechanisms of toxicity in different cell types at different doses. It can not only stimulate cell proliferation but also inhibit cell viability, induce cell apoptosis, and cause cell death. Thus, the objective of this review is to summarize the available mechanisms and current evidence of what is known about the cell proliferation or cell death induced by ZEA. An increasing number of studies have suggested that ZEA promoted cell proliferation attributing to its estrogen-like effects and carcinogenic properties. What’s more, many studies have indicated that ZEA caused cell death via affecting the distribution of the cell cycle, stimulating oxidative stress and inducing apoptosis. In addition, several studies have revealed that autophagy and some antioxidants can reverse the damage or cell death induced by ZEA. This review thoroughly summarized the metabolic process of ZEA and the molecular mechanisms of ZEA stimulating cell proliferation and cell death. It concluded that a low dose of ZEA can exert estrogen-like effects and carcinogenic properties, which can stimulate the proliferation of cells. While, in addition, a high dose of ZEA can cause cell death through inducing cell cycle arrest, oxidative stress, DNA damage, mitochondrial damage, and apoptosis.

Differential Gene Expression Analysis of Bovine Macrophages after Exposure to the Penicillium Mycotoxins Citrinin and/or Ochratoxin A

Mycotoxins produced by fungal species commonly contaminate livestock feedstuffs, jeopardizing their health and diminishing production. Citrinin (CIT) and ochratoxin A (OTA) are mycotoxins produced by Penicillium spp. and commonly co-occur. Both CIT and OTA can modulate immune response by inhibiting cell proliferation and differentiation, altering cell metabolism, and triggering programmed cell death. The objective of this study was to determine the effects of sublethal exposure (i.e., the concentration that inhibited cell proliferation by 25% (IC₂₅)) to CIT, OTA or CIT + OTA on the bovine macrophage transcriptome. Gene expression was determined using the Affymetrix Bovine Genome Array. After 6 h of exposure to CIT, OTA or CIT + OTA, the number of differentially expressed genes (DEG), respectively, was as follows: 1471 genes (822 up-regulated, 649 down-regulated), 5094 genes (2611 up-regulated, 2483 down-regulated) and 7624 genes (3984 up-regulated, 3640 down-regulated). Of these, 179 genes (88 up-regulated, 91 down-regulated) were commonly expressed between treatments. After 24 h of exposure to CIT, OTA or CIT + OTA the number of DEG, respectively, was as follows: 3230 genes (1631 up-regulated, 1599 down-regulated), 8558 genes (4167 up-regulated, 4391 down-regulated), and 10,927 genes (6284 up-regulated, 4643 down-regulated). Of these, 770 genes (247 up-regulated, 523 down-regulated) were commonly expressed between treatments. The categorization of common biological functions and pathway analysis suggests that the IC₂₅ of both CIT and OTA, or their combination, induces cellular oxidative stress, a slowing of cell cycle progression, and apoptosis. Collectively, these effects contribute to inhibiting bovine macrophage proliferation.

Zearalenone as an endocrine disruptor in humans

Zearalenone (ZEA), a fungal mycotoxin, is present in a wide range of human foods. Many animal studies have found ZEA to possess a disruptive effect on the hormonal balance, mainly due to its similarity to naturally-occurring estrogens. With increasing consciousness of the adverse effects of endocrine disruptors on human health, it is becoming more important to monitor ZEA concentrations in food and identify its potential effects on human health. Based on a review of recent studies on animal models and molecular pathways in which ZEA is reported to have an influence on humans, we postulate that ZEA might act as an endocrine disruptor in humans in a similar way to animals. Moreover, its endocrine-disrupting effect might be also a causative factor in carcinogenesis. This review article summarizes the latest knowledge about the influence of ZEA on the human hormonal balance.

Microarray based gene expression analysis of Sus Scrofa duodenum exposed to zearalenone: significance to human health

Background

Zearalenone (ZEA) is a secondary metabolite produced by Fusarium species. ZEA was proved to exert a wide range of unwanted side effects, but its mechanism of action, particularly at duodenum levels, remains unclear. In our study based on the microarray technology we assessed the alteration of gene expression pattern Sus scrofa duodenum which has been previously exposed to ZEA. Gene expression data was validated by qRT-PCR and ELISA. The gene expression data were further extrapolated the results to their human orthologues and analyzed the data in the context of human health using IPA (Ingenuity Pathways Analysis).

Results

Using Agilent microarray technology, we found that gene expression pattern was significantly affected by ZEA exposure, considering a 2-fold expression difference as a cut-off level and a p-value < 0.05. In total, we found 1576 upregulated and 2446 downregulated transcripts. About 1084 genes (764 downregulated and 751 overexpressed) were extrapolated to their human orthologues. IPA analysis showed various altered key cellular and molecular pathways. As expected, we observed a significant alteration of immune response related genes, MAPK (mitogen activate protein kinases) pathways or Toll-Like Receptors (TLRs). What captured our attention was the modulation of pathways related to the activation of early carcinogenesis.

Conclusions

Our data demonstrate that ZEA has a complex effect at duodenum level. ZEA is able to activate not only the immune response related genes, but also those relate to colorectal carcinogenesis. The effects can be more dramatic when connected with the exposure to other environmental toxic agents or co-occurrence with different microorganisms.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-016-2984-8) contains supplementary material, which is available to authorized users.

Evaluation of cellular and molecular impact of zearalenone and Escherichia coli co-exposure on IPEC-1 cells using microarray technology

Background

The gastrointestinal tract is the primary site of toxin interaction, an interface between the organism and its surroundings. In this study, we assessed the alteration of intestinal mRNA profile in the case of co-occurrence of zearalenone (ZEA), a secondary Fusarium metabolite, and Escherichia coli (E. coli), on the intestinal porcine epithelial cells IPEC-1. We chose this model since the pig is a species which is susceptible to pathogen and mycotoxin co-exposure.

Results

After treating the cells with the two contaminants, either separately or in combination, the differential gene expression between groups was assessed, using the microarray technology. Data analysis identified 1691 upregulated and 797 downregulated genes as a response to E. coli exposure, while for ZEA treated cells, 303 genes were upregulated and 49 downregulated. The co-contamination led to 991 upregulated and 800 downregulated genes. The altered gene expression pattern was further classified into 8 functional groups. In the case of co-exposure to ZEA and E.coli, a clear increase of proinflammatory mechanisms.

Conclusions

These results demonstrate the complex effect of single or multiple contaminants exposure at cellular and molecular level, with significant implications that might lead to the activation of pathological mechanisms. A better understanding of the effects of co-contamination is mandatory in developing novel exposure regulations and prevention measures.

Cytotoxic effects of zearalenone and its metabolites and antioxidant cell defense in CHO-K1 cells

Zearalenone (ZEA) and its metabolites (α-zearalenol; α-ZOL, β-zearalenol; β-ZOL) are secondary metabolites of Fusarium fungi that produce cell injury. The present study explores mycotoxin-induced cell damage and cellular protection mechanisms in CHO-K1 cells. Cytotoxicity has been determined by reactive oxygen species (ROS) production and DNA damage. ROS production was determined using the fluorescein assay and DNA strand breakage by comet assay. Intracellular protection systems were glutathione (GSH), glutathione peroxidase (GPx), catalase (CAT) and superoxide dismutase (SOD). The results demonstrated that all mycotoxins increased the ROS levels up to 5.3-fold the control levels in CHO-K1 cells. Zearalenone metabolites, but not ZEA, increased DNA damage 43% (α-ZOL) and 28% (β-ZOL) compared to control cells. The GSH levels decreased from 18% to 36%. The GPx and SOD activities respectively increased from 26% to 62% and from 23% to 69% in CHO-K1 cells, whereas CAT activity decreased from 14% to 52%. In addition, intracellular ROS production was induced by ZEA and its metabolites. The endogenous antioxidant system components GSH, GPx and SOD were activated against ZEA and its metabolites. These antioxidant system components thus could contribute to decrease cell injury by ZEA and its metabolites.

DNA Methylation Analysis: Choosing the Right Method

In the burgeoning field of epigenetics, there are several methods available to determine the methylation status of DNA samples. However, choosing the method that is best suited to answering a particular biological question still proves to be a difficult task. This review aims to provide biologists, particularly those new to the field of epigenetics, with a simple algorithm to help guide them in the selection of the most appropriate assay to meet their research needs. First of all, we have separated all methods into two categories: those that are used for: (1) the discovery of unknown epigenetic changes; and (2) the assessment of DNA methylation within particular regulatory regions/genes of interest. The techniques are then scrutinized and ranked according to their robustness, high throughput capabilities and cost. This review includes the majority of methods available to date, but with a particular focus on commercially available kits or other simple and straightforward solutions that have proven to be useful.

The influence of N-acetyl-l-cysteine on damage of porcine oocyte exposed to zearalenone in vitro

Zearalenone (ZEA), one of the mycotoxins produced by Fusarium fungi, impacts porcine reproduction by interfering with the estrogen signaling pathway. Previous studies have shown that ZEA inhibits porcine oocyte maturation through the formation of aberrant spindle. To explore the effect of ZEA on porcine oocyte meiotic maturation, the extent of both nuclear and cytoplasmic maturation was examined in this study. Compared with control group, presence of ZEA (3 μM) during oocyte maturation, significantly inhibited the polar body extrusions from 71% to 51%, and significantly increased intracellular reactive oxygen species (ROS) level (12.01 vs. 5.89). Intracellular glutathione (GSH) content in ZEA treatment group was lower than in the control group (1.08 pmol/oocyte vs. 0.18 pmol/oocyte), and cortical granules of cortical area distributed oocytes were reduced (88% vs. 62%). ZEA decreases cumulus expansion in both morphology and mRNA level (HAS2, PTX3, TNFAIP6 and CX43). Addition of N-acetyl-l-cysteine (NAC) to the oocyte maturation media reversed the ZEA-induced inhibition of polar body extrusion (from 69% to 81%), up-regulated ROS (from 7.9 to 6.5), down-regulated GSH content (from 0.16 to 0.82 pmol/oocyte) and recovered cumulus cells expansion in morphology and mRNA level. It is concluded that ZEA affects both oocyte nucleus and cytoplasmic maturation during in vitro maturation, and NAC can reverse these damages to some extent.

Food contaminant zearalenone and its metabolites affect cytokine synthesis and intestinal epithelial integrity of porcine cells

The intestinal epithelium is the first barrier against food contaminants. Zearalenone (ZEN) is an estrogenic mycotoxin that was identified as a common contaminant of cereal grains and food and feedstuffs. In the present study, we have investigated the in vitro effects of ZEN and some of its metabolites (α-ZOL, β-ZOL) in concentrations of 10–100 µM on a swine epithelial cell line: Intestinal porcine epithelial cells (IPEC-1). We demonstrated that both ZEN metabolites were more toxic for IPEC cells as resulted from the XTT test, while for doses lower than 10 µM, only β-ZOL showed a more pronounced cytotoxicity versus epithelial cells as resulted from neutral red assay. ZEN has no effect on TER values, while α-ZOL significantly decreased the TER values, starting with day 4 of treatment. β-ZOL had a dual effect, firstly it induced a significant increase of TER, and then, starting on day 6, it induced a dramatic decrease of TER values as compared with on day 0. Concerning the cytokine synthesis, our results showed that ZEN has a tendency to increase the synthesis of IL-8 and IL-10. By contrast, α- and β-ZOL decreased the expression of both IL-8 and IL-10, in a dose dependent manner. In conclusion, our results showed that ZEN and its metabolites differently affected porcine intestinal cell viability, transepithelial resistance and cytokine synthesis with important implication for gut health.

Altered oxidative stress, apoptosis/autophagy, and epigenetic modifications in Zearalenone-treated porcine oocytes

ZEN affected porcine oocyte maturation and early embryonic development. Oxidative stress, autophagy and apoptosis occurred. Aberrant epigenetic modifications were also observed.

Physiologically-based toxicokinetic modeling of zearalenone and its metabolites: application to the Jersey girl study

Zearalenone (ZEA), a fungal mycotoxin, and its metabolite zeranol (ZAL) are known estrogen agonists in mammals, and are found as contaminants in food. Zeranol, which is more potent than ZEA and comparable in potency to estradiol, is also added as a growth additive in beef in the US and Canada. This article presents the development and application of a Physiologically-Based Toxicokinetic (PBTK) model for ZEA and ZAL and their primary metabolites, zearalenol, zearalanone, and their conjugated glucuronides, for rats and for human subjects. The PBTK modeling study explicitly simulates critical metabolic pathways in the gastrointestinal and hepatic systems. Metabolic events such as dehydrogenation and glucuronidation of the chemicals, which have direct effects on the accumulation and elimination of the toxic compounds, have been quantified. The PBTK model considers urinary and fecal excretion and biliary recirculation and compares the predicted biomarkers of blood, urinary and fecal concentrations with published in vivo measurements in rats and human subjects. Additionally, the toxicokinetic model has been coupled with a novel probabilistic dietary exposure model and applied to the Jersey Girl Study (JGS), which involved measurement of mycoestrogens as urinary biomarkers, in a cohort of young girls in New Jersey, USA. A probabilistic exposure characterization for the study population has been conducted and the predicted urinary concentrations have been compared to measurements considering inter-individual physiological and dietary variability. The in vivo measurements from the JGS fall within the high and low predicted distributions of biomarker values corresponding to dietary exposure estimates calculated by the probabilistic modeling system. The work described here is the first of its kind to present a comprehensive framework developing estimates of potential exposures to mycotoxins and linking them with biologically relevant doses and biomarker measurements, including a systematic characterization of uncertainties in exposure and dose estimation for a vulnerable population.