Deoxynivalenol induces apoptosis and autophagy in human prostate epithelial cells via PI3K/Akt signaling pathway

Necroptosis contributes to the intestinal toxicity of deoxynivalenol and is mediated by methyltransferase SETDB1

Deoxynivalenol (DON) is a secondary metabolite produced by fungi, which causes serious health issues worldwide due to its widespread presence in human and animal diets. Necroptosis is a newly proposed cell death mode and has been proposed as a potential mechanism of intestinal disease. This study aimed to investigate the role of necroptosis in intestinal damage caused by DON exposure. Piglets were fed diets with or without 4 mg/kg DON for 3 weeks or given a gavage of 2 mg/kg BW DON or sterile saline to investigate the effects of chronic or acute DON exposure on the gut, respectively. IPEC-1 cells were challenged with different concentrations of DON to investigate the effect of DON exposure on the intestinal epithelial cells (IECs) in vitro. Subsequently, the inhibitors of necroptosis were used to treat cells or piglets prior to DON challenge. Chronic and acute DON exposure both caused morphological damage, reduction of disaccharidase activity, decrease of tight junction protein expression, inflammation of the small intestine, and necroptosis of intestinal epithelial cells in piglets. Necroptosis was also detected when IPEC-1 cell damage was induced by DON in vitro. The suppression of necroptosis in IPEC-1 cells by inhibitors (necrostatin-1 (Nec-1), GSK'872, or GW806742X) alleviated cell death, the decrease of tight junction protein expression, oxidative stress, and the inflammatory response induced by DON. Furthermore, pre-treatment with Nec-1 in piglets was also observed to protect the intestine against DON-induced enterotoxicity. Additionally, the expression of histone methyltransferase SETDB1 was abnormally downregulated upon chronic and acute DON exposure in piglets, and necroptosis was activated in IPEC-1 cells due to knockout of SETDB1. Collectively, these results demonstrate that necroptosis of IECs is a mechanism of DON-induced enterotoxicity and SETDB1 mediates necroptosis upon DON exposure in IECs, suggesting the potential for targeted inhibition of necroptosis to alleviate mycotoxin-induced enterotoxicity and intestinal disease.

Selenium maintains intestinal epithelial cells to activate M2 macrophages against deoxynivalenol injury

Selenium (Se) is indispensable in alleviating various types of intestinal injuries. Here, we thoroughly investigated the protective effect of Se on the regulation of the epithelial cell-M2 macrophages pathway in deoxynivalenol (DON)-induced intestinal damage. In the present study, Se has positive impacts on gut health by improving gut barrier function and reducing the levels of serum DON in vivo. Furthermore, our study revealed that Se supplementation increased the abundances of GPX4, p-PI3K, and AKT, decreased the levels of 4-HNE and inhibited ferroptosis. Moreover, when mice were treated with DON and Fer-1(ferroptosis inhibitor), ferroptosis was suppressed and PI3K/AKT pathway was activated. These results indicated that GPX4-PI3K/AKT-ferroptosis was a predominant pathway in DON-induced intestinal inflammation. Interestingly, we discovered that both the number of M2 anti-inflammatory macrophages and the levels of CSF-1 decreased while the pro-inflammatory cytokine IL-6 increased in the intestine and MODE-K cells supernatant. Therefore, Se supplementation activated the CSF-1-M2 macrophages axis, resulting in a decrease in IL-6 expression and an enhancement of the intestinal anti-inflammatory capacity. This study provides novel insights into how intestinal epithelial cells regulate the CSF-1-M2 macrophage pathway, which is essential in maintaining intestinal homeostasis confer to environmental hazardous stimuli.

Evaluation of Cross-Talk and Alleviate Potential of Cytotoxic Factors Induced by Deoxynivalenol in IPEC-J2 Cells Interference with Curcumin

Deoxynivalenol (DON) is a mycotoxin produced by Fusarium graminearum, and curcumin (CUR) is a natural polyphenolic compound found in turmeric. However, the combined treatment of CUR and DON to explore the mitigating effect of CUR on DON and their combined mechanism of action is not clear. Therefore, in this study, we established four treatment groups (CON, CUR, DON and CUR + DON) to investigate their mechanism in the porcine intestinal epithelial cells (IPEC-J2). In addition, the cross-talk and alleviating potential of CUR interfering with DON-induced cytotoxic factors were evaluated by in vitro experiments; the results showed that CUR could effectively inhibit DON-exposed activated TNF-α/NF-κB pathway, attenuate DON-induced apoptosis, and alleviate DON-induced endoplasmic reticulum stress and oxidative stress through PERK/CHOP pathways, which were verified at both mRNA and protein levels. In conclusion, these promising findings may contribute to the future use of CUR as a novel feed additive to protect livestock from the harmful effects of DON.

FOXO3a/PI3K/Akt pathway participates in the ROS- induced apoptosis triggered by α-ZEL and β-ZEL

Zearalenone (ZEN), an estrogenic mycotoxin, is one of the most common food and feed contaminants. Also, its metabolites α-zearalenol (α-ZEL) and β-zearalenol (β-ZEL) are considered to induce oxidative stress, however its effect in prostate cells is not known yet. Our previous observations showed that forehead box transcription factor 3a (FOXO3a) expression is modified in hormone- sensitive cells in the response to mycotoxins, similar to the phosphoinositide 3-kinase (PI3K)/ protein kinase B (Akt) pathway. Thus, this study evaluated the direct molecular effect of α-ZEL and β-ZEL in a dose of 30 µM in hormone-dependent human prostate cancer (PCa) cells with the focus of the involvement of FOXO3a and PI3K/Akt signaling pathway in that effect. We observed that both active metabolites of ZEN reduced cell viability, induced oxidative stress, cell cycle arrest and apoptosis in PCa cells. Furthermore, we observed that FOXO3a as well as PI3K/Akt signaling pathway participate in ZELs induced toxicity in PCa cells, indicating that this signaling pathway might be a regulator of mycotoxin-induced toxicity generally.

Autophagy modulation changes mechano-chemical sensitivity of T24 bladder cancer cells

Bladder cancer cells possess unique adaptive capabilities: shaped by their environment, cells face a complex chemical mixture of metabolites and xenobiotics accompanied by physiological mechanical cues. These responses might translate into resistance to chemotherapeutical regimens and can largely rely on autophagy. Considering molecules capable of rewiring tumor plasticity, compounds of natural origin promise to offer valuable options. Fungal derived metabolites, such as bafilomycin and wortmannin are widely acknowledged as autophagy inhibitors. Here, their potential to tune bladder cancer cells´ adaptability to chemical and physical stimuli was assessed. Additionally, dietary occurring mycotoxins were also investigated, namely deoxynivalenol (DON, 0.1-10 µM) and fusaric acid (FA, 0.1-1 mM). Endowing a Janus' face behavior, DON and FA are on the one side described as toxins with detrimental health effects. Concomitantly, they are also explored experimentally for selective pharmacological applications including anticancer activities. In non-cytotoxic concentrations, bafilomycin (BAFI, 1-10 nM) and wortmannin (WORT, 1 µM) modified cell morphology and reduced cancer cell migration. Application of shear stress and inhibition of mechano-gated PIEZO channels reduced cellular sensitivity to BAFI treatment (1 nM). Similarly, for FA (0.5 mM) PIEZO1 expression and inhibition largely aligned with the modulatory potential on cancer cells motility. Additionally, this study highlighted that the activity profile of compounds with similar cytotoxic potential (e.g. co-incubation DON with BAFI or FA with WORT) can diverge substantially in the regulation of cell mechanotransduction. Considering the interdependence between tumor progression and response to mechanical cues, these data promise to provide a novel viewpoint for the study of chemoresistance and associated pathways.

Paternal lipopolysaccharide exposure induced intrauterine growth restriction via the inactivation of placental MEST/PI3K/AKT pathway in mice

Maternal lipopolysaccharide (LPS) exposure during pregnancy has been related to IUGR. Here, we explored whether paternal LPS exposure before mating impaired fetal development. All male mice except controls were intraperitoneally injected with LPS every other day for a total of five injections. The next day after the last LPS, male mice were mated with untreated female mice. Interestingly, fetal weight and crown-rump length were reduced, while the incidence of IUGR was increased in paternal LPS exposure group. Additionally, paternal LPS exposure leaded to poor placental development through causing cell proliferation inhibition and apoptosis. Additional experiment demonstrated that the inactivation of placental PI3K/AKT pathway might be involved in paternal LPS-induced cell proliferation inhibition and apoptosis of trophoblast cells. Furthermore, the mRNA and protein levels of mesoderm specific transcript (MEST), a maternally imprinted gene with paternal expression, were significantly decreased in mouse placentas from paternal LPS exposure. Further analysis showed that paternal LPS exposure caused the inactivation of placental PI3K/AKT pathway and then cell proliferation inhibition and apoptosis might be via down-regulating placental MEST. Overall, our results provide evidence that paternal LPS exposure causes poor placental development and subsequently IUGR may be via down-regulating MEST/PI3K/AKT pathway, and then inducing cell proliferation inhibition and apoptosis in placentas.

Estrogen receptor α mediates alternariol-induced apoptosis and modulation of the invasiveness of ovarian cancer cells

Mycotoxins are secondary metabolites of fungi that may affect both human and animal health. Some of them possess estrogenic activity, due to direct binding to estrogen receptors (ERs) and hence disturb the hormonal balance of the organism. Alternariol (AOH) was previously reported as genotoxic, estrogenic and immunomodulatory agent. However, detailed mechanism of its action has not been fully elucidated. Estrogen receptor α (ERα) was previously reported to modulate the proliferation and invasiveness of ovarian cancer cells. Thus, we decided to verify whether estrogenic-like mycotoxin may affect ovarian cancer cells via ERα. The results showed that AOH induces apoptosis and oxidative stress and that these effects are partially modulated by ERα. Moreover, AOH decreases the invasion and migration of ovarian cancer cells and promotes changes in the expression of genes and proteins that are associated with the invasiveness of cancer i.e. MMP9, SNAIL1/2, ZEB1/2, VIM, CDH1 and CDH2. In conclusion, we postulate that AOH might significantly affect the viability and invasiveness of ovarian cancer cells via modulation of ERα and therefore possibly act as an endocrine disruptive agent in ovarian cancer cells.

Deoxynivalenol: Emerging Toxic Mechanisms and Control Strategies, Current and Future Perspectives

Deoxynivalenol (DON) is the most frequently present mycotoxin contaminant in food and feed, causing a variety of toxic effects in humans and animals. Currently, a series of mechanisms involved in DON toxicity have been identified. In addition to the activation of oxidative stress and the MAPK signaling pathway, DON can activate hypoxia-inducible factor-1α, which further regulates reactive oxygen species production and cancer cell apoptosis. Noncoding RNA and signaling pathways including Wnt/β-catenin, FOXO, and TLR4/NF-κB also participate in DON toxicity. The intestinal microbiota and the brain-gut axis play a crucial role in DON-induced growth inhibition. In view of the synergistic toxic effect of DON and other mycotoxins, strategies to detect DON and control it biologically and the development of enzymes for the biodegradation of various mycotoxins and their introduction in the market are the current and future research hotspots.

A Review of Gut Microbiota-Derived Metabolites in Tumor Progression and Cancer Therapy

Gut microbiota-derived metabolites are key hubs connecting the gut microbiome and cancer progression, primarily by remodeling the tumor microenvironment and regulating key signaling pathways in cancer cells and multiple immune cells. The use of microbial metabolites in radiotherapy and chemotherapy mitigates the severe side effects from treatment and improves the efficacy of treatment. Immunotherapy combined with microbial metabolites effectively activates the immune system to kill tumors and overcomes drug resistance. Consequently, various novel strategies have been developed to modulate microbial metabolites. Manipulation of genes involved in microbial metabolism using synthetic biology approaches directly affects levels of microbial metabolites, while fecal microbial transplantation and phage strategies affect levels of microbial metabolites by altering the composition of the microbiome. However, some microbial metabolites harbor paradoxical functions depending on the context (e.g., type of cancer). Furthermore, the metabolic effects of microorganisms on certain anticancer drugs such as irinotecan and gemcitabine, render the drugs ineffective or exacerbate their adverse effects. Therefore, a personalized and comprehensive consideration of the patient's condition is required when employing microbial metabolites to treat cancer. The purpose of this review is to summarize the correlation between gut microbiota-derived metabolites and cancer, and to provide fresh ideas for future scientific research.

Pyroptosis-Mediated Damage Mechanism by Deoxynivalenol in Porcine Small Intestinal Epithelial Cells

Deoxynivalenol (DON) is known as a vomitoxin, which frequently contaminates feedstuffs, such as corn, wheat, and barley. Intake of DON-contaminated feed has been known to cause undesirable effects, including diarrhea, emesis, reduced feed intake, nutrient malabsorption, weight loss, and delay in growth, in livestock. However, the molecular mechanism of DON-induced damage of the intestinal epithelium requires further investigation. Treatment with DON triggered ROS in IPEC-J2 cells and increased the mRNA and protein expression levels of thioredoxin interacting protein (TXNIP). To investigate the activation of the inflammasome, we confirmed the mRNA and protein expression levels of the NLR family pyrin domain containing 3 (NLRP3), apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), and caspase-1 (CASP-1). Moreover, we confirmed that caspase mediates the mature form of interleukin-18, and the cleaved form of Gasdermin D (GSDMD) was increased. Based on these results, our study suggests that DON can induce damage through oxidative stress and pyroptosis in the epithelial cells of the porcine small intestine via NLRP3 inflammasome.

Assessment of information as regards the toxicity of deoxynivalenol for horses and poultry

In 2017, the EFSA Panel on Contaminants in the Food Chain (CONTAM) adopted a Scientific Opinion on the risks for animal health related to the presence of deoxynivalenol (DON) and its acetylated and modified forms in food and feed. No observed adverse effect levels (NOAELs) and lowest observed adverse effect levels (LOAELs) were derived for different animal species. For horses, an NOAEL of 36 mg DON/kg feed was established, the highest concentration tested and not showing adverse effects. For poultry, an NOAEL of 5 mg DON/kg feed for broiler chickens and laying hens, and an NOAEL of 7 mg DON/kg feed for ducks and turkeys was derived. The European Commission requested EFSA to review the information regarding the toxicity of DON for horses and poultry and to revise, if necessary, the established reference points (RPs). Adverse effect levels of 1.9 and 1.7 mg DON/kg feed for, respectively, broiler chickens and turkeys were derived from reassessment of existing studies and newly available literature, showing that DON causes effects on the intestines, in particular the jejunum, with a decreased villus height but also histological damage. An RP for adverse animal health effects of 0.6 mg/kg feed for broiler chickens and turkeys, respectively, was established. For horses, an adverse effect level of 5.6 mg DON/kg feed was established from studies showing reduced feed intake, with an RP for adverse animal health effects of 3.5 mg/kg feed. For ducks and laying hens, RPs remain unchanged. Based on mean and P95 (UB) exposure estimates performed in the previous Opinion, the risk of adverse health effects of feeds containing DON was considered a potential concern for broiler chickens and turkeys. For horses, the risk for adverse health effects from feed containing DON is low.

Deoxynivalenol Induces Apoptosis via FOXO3a-Signaling Pathway in Small-Intestinal Cells in Pig

Deoxynivalenol (DON) is a mycotoxin that is found in feed ingredients derived from grains such as corn and wheat. Consumption of DON-contaminated feed has been shown to cause damage to the intestine, kidneys, and liver. However, the molecular mechanism by which DON exerts its effect in the small intestine is not completely understood. As a result, we profiled gene expression in intestinal epithelial cells treated with DON and examined the molecular function in vitro. We hypothesized that DON could induce apoptosis via the FOXO3a-signaling pathway in intestinal epithelial cells based on these findings. DON induced the apoptosis and the translocation of FOXO3a into the nucleus. Moreover, the inhibiting of FOXO3a alleviated the apoptosis and expression of apoptosis-related genes (TRAL, BCL-6, CASP8, and CASP3). ERK1/2 inhibitor treatment suppressed the translocation of FOXO3a into the nucleus. Our discovery suggests that DON induces apoptosis in intestinal epithelial cells through the FOXO3a-signaling pathway.