DON shares a similar mode of action as the ribotoxic stress inducer anisomycin while TBTO shares ER stress patterns with the ER stress inducer thapsigargin based on comparative gene expression profiling in Jurkat T cells

Deoxynivalenol Damages Corneal Epithelial Cells and Exacerbates Inflammatory Response in Fungal Keratitis

BACKGROUND

Fungal keratitis (FK) is a kind of infectious keratopathy with a high rate of blindness worldwide. Deoxynivalenol (DON) has been proven to have multiple toxic effects on humans and animals.

OBJECTIVES

The aim of this study was to explore a possible pathogenic role of DON in FK.

METHODS

We first made an animal model of FK in New Zealand white rabbits, and then attempted to detect DON in a culture medium in which Fusarium solani had been grown and also in the corneal tissue of the animal model of Fusarium solani keratitis. Next, a model of DON damage in human corneal epithelial cells (HCECs) was constructed to evaluate effects of DON on the activity, migration ability, cell cycle, and apoptosis in the HCECs. Then, putative the toxic damaging effects of DON on rabbit corneal epithelial cells and the impact of the repair cycle were studied. The expression levels of inflammatory factors in the corneas of the animal model and in the model of DON-damaged HCECs were measured.

RESULTS

The Fusarium solani strain used in this study appeared to have the potential to produce DON, since DON was detected in the corneal tissue of rabbits which had been inoculated with this Fusarium solani strain. DON was found to alter the morphology of HCECs, to reduce the activity and to inhibit the proliferation and migration of HCECs. DON also induced the apoptosis and S-phase arrest of HCECs. In addition, DON was found to damage rabbit corneal epithelial cells, to prolong the corneal epithelial regeneration cycle, and to be associated with the upregulated expression of inflammatory factors in HCECs and rabbit corneas.

CONCLUSIONS

DON appears to have a toxic damaging effect on HCECs in FK, and to induce the expression of inflammatory factors, leading to the exacerbation of keratitis and the formation of new blood vessels. Future studies will explore the possibility of developing a test to detect DON in ophthalmic settings to aid the rapid diagnosis of FK, and to develop DON neutralizers and adsorbents which have the potential to improve keratocyte status, inhibit apoptosis, and alleviate inflammation, therein providing new thinking for therapy of clinical FK.

An update on T2-toxins: metabolism, immunotoxicity mechanism and human assessment exposure of intestinal microbiota

Mycotoxins are naturally produced secondary metabolites or low molecular organic compounds produced by fungus with high diversification, which cause mycotoxicosis (food contamination) in humans and animals. T-2 toxin is simply one of the metabolites belonging to fungi trichothecene mycotoxin. Specifically, Trichothecenes-2 (T-2) mycotoxin of genus fusarium is considered one of the most hotspot agricultural commodities and carcinogenic compounds worldwide. There are well-known examples of salmonellosis in mice and pigs, necrotic enteritis in chickens, catfish enteric septicemia and colibacillosis in pigs as T-2 toxic agent. On the other hand, it has shown a significant reduction in the Salmonella population's aptitude in the pig intestinal tract. Although the impact of the excess Fusarium contaminants on humans in creating infectious illness is less well-known, some toxins are harmful; for example, salmonellosis and colibacillosis have been frequently observed in humans. More than 20 different metabolites are synthesized and excreted after ingestion, but the T-2 toxin is one of the most protuberant metabolites. Less absorption of mycotoxins in intestinal tract results in biotransformation of toxic metabolites into less toxic variants. In addition to these, effects of microbiota on harmful mycotoxins are not limited to intestinal tract, it may harm the other human vital organs. However, detoxification of microbiota is considered as an alternative way to decontaminate the feed for both animals and humans. These transformations of toxic metabolites depend upon the formation of metabolites. This study is complete in all perspectives regarding interactions between microbiota and mycotoxins, their mechanism and practical applications based on experimental studies.

Deoxynivalenol exposure during pregnancy has adverse effects on placental structure and immunity in mice model

Deoxynivalenol (DON), a highly prevalent food contaminant, is known to induce reproductive and immunotoxicity in humans upon exposure. The present study focused on the consequences of exposure to DON during pregnancy for placental barrier and immune function, as well as fetal survival. Female mice received diets contaminated with DON (6.25 and 12.5 mg/kg of diet), starting immediately after mating until the end of the experiment. On day 17 of pregnancy the animals were killed, and maternal and fetal samples were collected for further analysis. Feeding on DON-contaminated diets decreased fetal survival, and DON was detected at significant levels in the fetus. Placentae from DON-exposed mice revealed a reduction in expression of junctional proteins, ZO-1, E-cadherin and claudins, upregulation of AHR mRNA expressions, and increase in IFN-ꝩ, IL-6 and IL-4 production. In conclusion, results of this study demonstrate harmful effects of DON on the course of pregnancy and fetal survival, which might be due to immunological changes in maternal immune organs and placenta. Altogether, these data underline the importance of the quality of maternal diet during pregnancy as they clearly demonstrate the potential harmful effects of a commonly present food-contaminant.

Calreticulin nuclear translocalization alleviates CaM/CaMKII/CREB signaling pathway to enhance chemosensitivity in HDAC inhibitor-resistant hepatocellular carcinoma cells

Calreticulin (CRT) is located in the endoplasmic reticulum (ER), it helps proteins fold correctly inside the ER, and acts as a modulator of Ca²⁺ homeostasis. Aberrant expression of CRT is implicated in several cancer types, qualifying CRT as a potential therapeutic target. However, it remains unclear how CRT affects specific oncogenic pathways. In this study, we used histone deacetylase inhibitors (HDACis) to establish drug-resistant liver cancer cells and further analyzed the molecular mechanism of development of drug resistance in those cells. The 2D gel electrophoresis and RT-PCR data showed that CRT was downregulated in HDACis-resistant cells by comparing with HA22T parental cells. We previously elucidated the development of drug-resistance in HCC cells via activation of PP1-eIF2α pathway, but not via ER stress pathway. Here, we show that thapsigargin induced ER stress through mechanism other than ER stress downstream protein GRP78-PERK to regulate CRT expression in HDACis-R cells. Moreover, the expression level of CRT was not the main cause of apoptosis in HDACis-resistant cells. Mechanistic studies identified the apoptosis factors in the nucleus-the HDACis-mediated overexpression of CRT, CRT translocation to the cell nucleus, and reduced CaM/CaMKII/CREB pathway-that led to chemosensitivity in HDACis-R HCC cells.

Deoxynivalenol: An Overview on Occurrence, Chemistry, Biosynthesis, Health Effects and Its Detection, Management, and Control Strategies in Food and Feed

Mycotoxins are fungi-produced secondary metabolites that can contaminate many foods eaten by humans and animals. Deoxynivalenol (DON), which is formed by Fusarium, is one of the most common occurring predominantly in cereal grains and thus poses a significant health risk. When DON is ingested, it can cause both acute and chronic toxicity. Acute signs include abdominal pain, anorexia, diarrhea, increased salivation, vomiting, and malaise. The most common effects of chronic DON exposure include changes in dietary efficacy, weight loss, and anorexia. This review provides a succinct overview of various sources, biosynthetic mechanisms, and genes governing DON production, along with its consequences on human and animal health. It also covers the effect of environmental factors on its production with potential detection, management, and control strategies.

The toxicity mechanisms of DON to humans and animals and potential biological treatment strategies

Deoxynivalenol, also known as vomitotoxin, is produced by Fusarium, belonging to the group B of the trichothecene family. DON is widely polluted, mainly polluting cereal crops such as wheat, barley, oats, corn and related cereal products, which are closely related to lives of people and animals. At present, there have been articles summarizing DON induced toxicity, biological detoxification and the protective effect of natural products, but there is no systematic summary of this information. In addition to ribosome and endoplasmic reticulum, recent investigations support that mitochondrion is also organelles that DON can damage. DON can't directly act on mitochondria, but can indirectly cause mitochondrial damage and changes through other means. DON can indirectly inhibit mitochondrial biogenesis and mitochondrial electron transport chain activity, ATP production, and mitochondrial transcription and translation. This review will provide the latest progress on mitochondria as the research object, and systematically summarizes all the toxic mechanisms of DON. Here, we discuss DON induced mitochondrial-mediated apoptosis and various mitochondrial toxicity. For the toxicity of DON, many methods have been derived to prevent or reduce the toxicity. Biological detoxification and the antioxidant effect of natural products are potentially effective treatments for DON toxicity.

Anisomycin induces hair cell death and blocks supporting cell proliferation in zebrafish lateral line neuromast

Ototoxicity of drugs is an important inducement for hearing loss. Anisomycin is a candidate drug for parasite, cancer, immunosuppression, and mental disease. However, the ototoxicity of anisomycin has not been examined. In this study, the ototoxicity of anisomycin was evaluated using zebrafish lateral line. We found the zebrafish treated with anisomycin during lateral line development could inhibit hair cell formation in a time- and dose-dependent manner. After neuromasts are mature with differentiated hair cells by 5 day post-fertilization, anisomycin could induce hair cell loss effectively through chronic exposure rather than acute exposure. TUNEL assay and qPCR of apoptosis related genes tp53, casp8, casp3a, and casp3b indicated that cell apoptotic was induced by chronic anisomycin exposure. Furthermore, knocking down tp53 with antisense morpholino could attenuate the hair cell loss induced by anisomycin. In addition, we found that anisomycin chronic exposure also inhibited the proliferation of supporting cell. Together, these results indicate that chronic anisomycin exposure could induce hair cell death and block supporting cell proliferation, which causes hair cell loss in zebrafish neuromast. This study provides primary ototoxicity evaluation for anisomycin.

Effect of chlorogenic acid on alleviating inflammation and apoptosis of IPEC-J2 cells induced by deoxyniyalenol

Deoxynivalenol (DON) is extensively detected in many kinds of foods and feeds to harm human and animal health. This research aims to investigate the effect of chlorogenic acid (CGA) on alleviating inflammation and apoptosis of swine jejunal epithelial cells (IPEC-J2) triggered by DON. The results demonstrated that cell viability was decreased when DON concentrations increased or incubation time expanded. The pretreatment with CGA (40 μg/mL) for 1 h increased cell viability, decreased lactate dehydrogenase (LDH) release and apoptosis in cells triggered by DON at 0.5 μg/mL for 6 h, compared with the DON alone-treated cells. Moreover, the mRNA abundances of IL-8, IL-6, TNF-α, COX-2, caspase-3, Bax and ASCT2 genes, and protein expressions of COX-2, Bax and ASCT2 were significantly down-regulated; while the mRNA abundances of ZO-1, claudin-1, occludin, PePT1 and GLUT2 genes, and protein expressions of ZO-1, claudin-1 and PePT1 were significantly up-regulated in the CGA + DON group, compared with the DON alone group. This study indicated that CGA pretreatment alleviated cytotoxicity, inflammation and apoptosis in DON-triggered IPEC-J2 cells, and protected intestinal cell integrity from DON damages.

The food contaminant deoxynivalenol provokes metabolic impairments resulting in non-alcoholic fatty liver (NAFL) in mice

The ribotoxin deoxynivalenol (DON) is a trichothecene found on cereals responsible for mycotoxicosis in both humans and farm animals. DON toxicity is characterized by reduced food intake, diminished nutritional efficiency and immunologic effects. The present study was designed to further characterize the alterations in energy metabolism induced by DON intoxication. We demonstrated that acute DON intoxication triggered liver steatosis associated with an altered expression of genes related to lipids oxidation, lipogenesis and lipolysis. This steatosis was concomitant to anorexia, hypoglycemia and a paradoxical transient insulin release. DON treatment resulted also in stimulation of central autonomic network regulating sympathetic outflow and adrenaline and glucocorticoids secretion. Furthermore, an increased expression of genes linked to inflammation and reticulum endoplasmic stress was observed in the liver of DON-treated mice. Finally, we propose that lipids mobilization from adipose tissues (AT) induced by DON intoxication drives hepatic steatosis since (1) genes encoding lipolytic enzymes were up-regulated in AT and (2) plasma concentration of triglycerides (TGs) and non-esterified fatty acids were increased during DON intoxication. Altogether, these data demonstrate that DON induced hormonal and metabolic dysregulations associated with a spectrum of hepatic abnormalities, evocative of a non-alcoholic fatty liver disease.

Transcriptional network inference and master regulator analysis of the response to ribosome-inactivating proteins in leukemia cells

Gene-regulatory networks reconstruction has become a very popular approach in applied biology to infer and dissect functional interactions of Transcription Factors (TFs) driving a defined phenotypic state, termed as Master Regulators (MRs). In the present work, cutting-edge bioinformatic methods were applied to re-analyze experimental data on leukemia cells (human myelogenous leukemia cell line THP-1 and acute myeloid leukemia MOLM-13 cells) treated for 6 h with two different Ribosome-Inactivating Proteins (RIPs), namely Shiga toxin type 1 (400 ng/mL) produced by Escherichia coli strains and the plant toxin stenodactylin (60 ng/mL), purified from the caudex of Adenia stenodactyla Harms. This analysis allowed us to identify the common early transcriptional response to 28S rRNA damage based on gene-regulatory network inference and Master Regulator Analysis (MRA). Both toxins induce a common response at 6 h which involves inflammatory mediators triggered by AP-1 family transcriptional factors and ATF3 in leukemia cells. We describe for the first time the involvement of MAFF, KLF2 and KLF6 in regulating RIP-induced apoptotic cell death, while receptor-mediated downstream signaling through ANXA1 and TLR4 is suggested for both toxins.

Astilbin ameliorates deoxynivalenol-induced oxidative stress and apoptosis in intestinal porcine epithelial cells (IPEC-J2)

Deoxynivalenol (DON) is a common mycotoxin, which often induces oxidative stress and cytotoxicity in humans and animals. Astilbin (AST), as a natural antioxidant, exhibits multiple pharmacological functions. The aim of this study was to investigate the effects of AST on alleviating DON-induced cytotoxicity in intestinal porcine epithelial cells (IPEC-J2). The results demonstrated that 0.5 μg/mL DON stimulation for 6 hours induced oxidative stress, inflammation and apoptosis in IPEC-J2 cells. AST enhanced the cell viability in a dose- and time-dependent manner. The addition of 20 μg/mL AST significantly increased cell viability, superoxide dismutase and catalase activities, Bcl-2 gene expression and the Bcl-2/Bax ratio (P < .05), and decreased lactate dehydrogenase release, malondialdehyde content and the relative expressions of genes associated with inflammation and apoptosis such as interleukin-6 and -8, tumor necrosis factor-alpha, cyclooxygenase-2, nuclear factor-kappaB, Bax and caspase-3 (P < .05). Simultaneously, zonula occludens-1, claudin-1 and PepT1 gene expressions were upregulated and occludin, ASCT2 and GLUT2 gene expressions were downregulated by the addition of AST, compared with the DON group (P < .05). These results indicated that 20 μg/mL AST could ameliorate oxidative stress, inflammation and apoptosis by enhancing antioxidant enzyme activities and intestinal barrier function, and reducing the expressions of inflammation and apoptosis genes, as well as improve the barrier function and nutrient transport and absorption in DON-induced IPEC-J2 cells.

Evaluation of seeds ethanolic extracts of Triplaris gardneriana Wedd. using in vitro and in vivo toxicological methods

Triplaris gardneriana Wedd. is a tree used in folk medicine to treat venereal diseases and inflammation as well as a source of biological compounds with antioxidant capacity. In order to assess the safety of these bioactive compounds, the present study aimed to determine the toxicity of an ethanolic extract of T. gardneriana, (EETg). Toxicological tests included hemolytic activity, toxicity toward the brine shrimp Artemia, cytotoxicity against breast cancer cells (MCF7) and acute oral toxicity in rodents. In addition, toxicogenomics techniques were used to determine genome expression in MCF7 cells exposed to EETg. The results showed that the extract exhibits approximately 60% of hemolytic activity at the highest tested concentration (64 µg/ml) and toxicity against nauplii of Artemia sp. (LC₅₀ of 67.85 µg/ml). Further, EETg appears to be cytotoxic to MCF7 (cell viability reduced to 40% at 250 µg/ml after 24 hr). Genomic data demonstrated differential expression of 14 genes. Data analysis indicated possible altered pathways (e.g., xenobiotic metabolism), possible adverse health risks (e.g., hepatotoxicity), and drugs with similar gene expression profile (e.g., antimicrobials). The investigation provides important information on potentially adverse aspects of EETg, which need to be considered prior to the therapeutic utilization of this plant.Abbreviations: EETg: ethanolic extract of T. gardneriana seeds; MCF7: michigan cancer foundation-7 which refers to a human breast cell line (adenocarcinoma); NGS: next-generation sequencing; edgeR: empirical analysis of digital gene expression data in R; Consensus: consensus path database; FDR: false discovery rate; NCBI: national center for biotechnology information; KEGG: kyoto encyclopedia of genes and genomes; Ingenuity: ingenuity pathway analysis software; CMAP: connectivity map; OECD: organization for economic co-operation and development; HL-60: human promyelocytic leukemia cells; PC3: prostate cancer cells.

Dual Function of a Novel Bacterium, Slackia sp. D-G6: Detoxifying Deoxynivalenol and Producing the Natural Estrogen Analogue, Equol

Deoxynivalenol (DON) is a highly abundant mycotoxin that exerts many adverse effects on humans and animals. Much effort has been made to control DON in the past, and bio-transformation has emerged as the most promising method. However, useful and effective application of bacterial bio-transformation for the purpose of inhibiting DON remains urgently needed. The current study isolated a novel DON detoxifying bacterium, Slackia sp. D-G6 (D-G6), from chicken intestines. D-G6 is a Gram-positive, non-sporulating bacterium, which ranges in size from 0.2–0.4 μm × 0.6–1.0 μm. D-G6 de-epoxidizes DON into a non-toxic form called DOM-1. Optimum conditions required for degradation of DON are 37–47 °C and a pH of 6–10 in WCA medium containing 50% chicken intestinal extract. Besides DON detoxification, D-G6 also produces equol (EQL) from daidzein (DZN), which shows high estrogenic activity, and prevents estrogen-dependent and age-related diseases effectively. Furthermore, the genome of D-G6 was sequenced and characterized. Thirteen genes that show potential for DON de-epoxidation were identified via comparative genomics. In conclusion, a novel bacterium that exhibits the dual function of detoxifying DON and producing the beneficial natural estrogen analogue, EQL, was identified.

The PERK Pathway Plays a Neuroprotective Role During the Early Phase of Secondary Brain Injury Induced by Experimental Intracerebral Hemorrhage

The protein kinase RNA-like endoplasmic reticulum kinase (PERK) pathway, which is a branch of the unfolded protein response, participates in a range of pathophysiological processes of neurological diseases. However, few studies have investigated the role of the PERK in intracerebral hemorrhage (ICH). The present study evaluated the role of the PERK pathway during the early phase of ICH-induced secondary brain injury (SBI) and its potential mechanisms. An autologous whole blood ICH model was established in rats, and cultured primary cortical neurons were treated with oxyhemoglobin to mimic ICH in vitro. We found that levels of phosphorylated alpha subunit of eukaryotic translation initiation factor 2 (p-eIF2α) and activating transcription factor 4 (ATF4) increased significantly and peaked at 12 h during the early phase of the ICH. To further elucidate the role of the PERK pathway, we assessed the effects of the PERK inhibitor, GSK2606414, and the eIF2α dephosphorylation antagonist, salubrinal, at 12 h after ICH both in vivo and in vitro. Inhibition of PERK with GSK2606414 suppressed the protein levels of p-eIF2α and ATF4, resulting in increase of transcriptional activator CCAAT/enhancer-binding protein homologous protein (CHOP) and caspase-12, which promoted apoptosis and reduced neuronal survival. Treatment with salubrinal yielded opposite results, which suggested that activation of the PERK pathway could promote neuronal survival and reduce apoptosis. In conclusion, the present study has demonstrated the neuroprotective effects of the PERK pathway during the early phase of ICH-induced SBI. These findings highlight the potential value of PERK pathway as a therapeutic target for ICH.

Deoxynivalenol induces apoptosis and disrupts cellular homeostasis through MAPK signaling pathways in bovine mammary epithelial cells

Deoxynivalenol (DON), a fungus-derived mycotoxin, also known as vomitoxin, is found in a wide range of cereal grains and grain-based food products. The biological toxicity of DON has been described in various species, but its toxicity and functional effects in mammary epithelial cells are unclear. In this study, we investigated the effect of DON on bovine mammary epithelial (MAC-T) cells using mechanistic approaches. We detected DON-induced cell cycle abrogation and calcium deficiency, leading to apoptotic cell death via MAPK signaling pathways. Moreover, we studied the transcriptional activation of blood and milk junctional regulators as well as inflammatory cytokines in response to DON. The results of this study contribute to a comprehensive understanding of DON-associated toxicity mechanisms in bovine mammary epithelial cells, which may facilitate the enhancement of milk stabilization in parallel with the establishment of safety profiles to protect against DON contamination in livestock farms and in the food industry.

IGFBP-3 Induced by Ribotoxic Stress Traffics From the Endoplasmic Reticulum to the Nucleus in Mammary Epithelial Cells

IGF-binding protein (IGFBP)-3 is a multifunctional protein that can exert IGF-independent effects on apoptosis. Anisomycin (ANS) is a potent inducer of IGFBP-3 production in bovine mammary epithelial cells (MECs), and knockdown of IGFBP-3 attenuates ANS-induced apoptosis. IGFBP-3 is present in the nucleus and the conditioned media in response to ANS. The goal of this study was to determine whether ribotoxic stress induced by ANS or a second ribotoxin, deoxynivalenol (DON), specifically regulates transport of IGFBP-3 to the nucleus and to determine the pathway by which it traffics. In ribotoxin-treated cells, both endogenous IGFBP-3 and transfected IGFBP-3 translocated to the nucleus. Inhibition of the nuclear transport protein importin-β with importazole reduced ribotoxin-induced nuclear IGFBP-3. Immunoprecipitation studies showed that ANS induced the association of IGFBP-3 and importin-β, indicating that ribotoxins specifically induce nuclear translocation via an importin-β‒dependent mechanism. To determine whether secretion of IGFBP-3 is required for nuclear localization, cells were treated with Pitstop 2 or brefeldin A to inhibit clathrin-mediated endocytosis or overall protein secretion, respectively. Neither inhibitor affected nuclear localization of IGFBP-3. Although the IGFBP-3 present in both the nucleus and conditioned media was glycosylated, secreted IGFBP-3 exhibited a higher molecular weight. Deglycosylation experiments with endoglycosidase Hf and PNGase indicated that secreted IGFBP-3 completed transit through the Golgi apparatus, whereas intracellular IGFBP-3 exited from the endoplasmic reticulum before transit through the Golgi. In summary, ANS and DON specifically induced nuclear localization of nonsecreted IGFBP-3 via an importin-β‒mediated event, which may play a role in their ability to induce apoptosis in MECs.

GEPSI: A Gene Expression Profile Similarity-Based Identification Method of Bioactive Components in Traditional Chinese Medicine Formula

The identification of bioactive components in traditional Chinese medicine (TCM) is an important part of the TCM material foundation research. Recently, molecular docking technology has been extensively used for the identification of TCM bioactive components. However, target proteins that are used in molecular docking may not be the actual TCM target. For this reason, the bioactive components would likely be omitted or incorrect. To address this problem, this study proposed the GEPSI method that identified the target proteins of TCM based on the similarity of gene expression profiles. The similarity of the gene expression profiles affected by TCM and small molecular drugs was calculated. The pharmacological action of TCM may be similar to that of small molecule drugs that have a high similarity score. Indeed, the target proteins of the small molecule drugs could be considered TCM targets. Thus, we identified the bioactive components of a TCM by molecular docking and verified the reliability of this method by a literature investigation. Using the target proteins that TCM actually affected as targets, the identification of the bioactive components was more accurate. This study provides a fast and effective method for the identification of TCM bioactive components.

Mycotoxin: Its Impact on Gut Health and Microbiota

The secondary metabolites produced by fungi known as mycotoxins, are capable of causing mycotoxicosis (diseases and death) in human and animals. Contamination of feedstuffs as well as food commodities by fungi occurs frequently in a natural manner and is accompanied by the presence of mycotoxins. The occurrence of mycotoxins' contamination is further stimulated by the on-going global warming as reflected in some findings. This review comprehensively discussed the role of mycotoxins (trichothecenes, zearalenone, fumonisins, ochratoxins, and aflatoxins) toward gut health and gut microbiota. Certainly, mycotoxins cause perturbation in the gut, particularly in the intestinal epithelial. Recent insights have generated an entirely new perspective where there is a bi-directional relationship exists between mycotoxins and gut microbiota, thus suggesting that our gut microbiota might be involved in the development of mycotoxicosis. The bacteria-xenobiotic interplay for the host is highlighted in this review article. It is now well established that a healthy gut microbiota is largely responsible for the overall health of the host. Findings revealed that the gut microbiota is capable of eliminating mycotoxin from the host naturally, provided that the host is healthy with a balance gut microbiota. Moreover, mycotoxins have been demonstrated for modulation of gut microbiota composition, and such alteration in gut microbiota can be observed up to species level in some of the studies. Most, if not all, of the reported effects of mycotoxins, are negative in terms of intestinal health, where beneficial bacteria are eliminated accompanied by an increase of the gut pathogen. The interactions between gut microbiota and mycotoxins have a significant role in the development of mycotoxicosis, particularly hepatocellular carcinoma. Such knowledge potentially drives the development of novel and innovative strategies for the prevention and therapy of mycotoxin contamination and mycotoxicosis.

Lung inflammation caused by inhaled toxicants: a review

Exposure of the lungs to airborne toxicants from different sources in the environment may lead to acute and chronic pulmonary or even systemic inflammation. Cigarette smoke is the leading cause of chronic obstructive pulmonary disease, although wood smoke in urban areas of underdeveloped countries is now recognized as a leading cause of respiratory disease. Mycotoxins from fungal spores pose an occupational risk for respiratory illness and also present a health hazard to those living in damp buildings. Microscopic airborne particulates of asbestos and silica (from building materials) and those of heavy metals (from paint) are additional sources of indoor air pollution that contributes to respiratory illness and is known to cause respiratory illness in experimental animals. Ricin in aerosolized form is a potential bioweapon that is extremely toxic yet relatively easy to produce. Although the aforementioned agents belong to different classes of toxic chemicals, their pathogenicity is similar. They induce the recruitment and activation of macrophages, activation of mitogen-activated protein kinases, inhibition of protein synthesis, and production of interleukin-1 beta. Targeting either macrophages (using nanoparticles) or the production of interleukin-1 beta (using inhibitors against protein kinases, NOD-like receptor protein-3, or P2X7) may potentially be employed to treat these types of lung inflammation without affecting the natural immune response to bacterial infections.

Protein phosphorylation profiling identifies potential mechanisms for direct immunotoxicity

Signaling networks are essential elements that are involved in diverse cellular processes. One group of fundamental components in various signaling pathways concerns protein tyrosine kinases (PTK). Various toxicants have been demonstrated to exert their toxicity via modulation of tyrosine kinase activity. The present study aimed to identify common cellular signaling pathways that are involved in chemical-induced direct immunotoxicity. To this end, an antibody array-based profiling approach was applied to assess effects of five immunotoxicants, two immunosuppressive drugs and two non-immunotoxic control chemicals on the phosphorylation of 28 receptor tyrosine kinases and 11 crucial signaling nodes in Jurkat T-cells. The phosphorylation of ribosomal protein S6 (RPS6) and of kinases Akt, Src and p44/42 were found to be commonly regulated by immunotoxicants and/or immunosuppressive drugs (at least three compounds), with the largest effect observed upon RPS6. Flow cytometry and Western blotting were used to further examine the effect of the model immunotoxicant TBTO on the components of the mTOR-p70S6K-RPS6 pathway. These analyses revealed that both TBTO and the mTOR inhibitor rapamycin inactivate RPS6, but via different mechanisms. Finally, a comparison of the protein phosphorylation data to previously obtained transcriptome data of TBTO-treated Jurkat cells resulted in a good correlation at the pathway level and indicated that TBTO affects ribosome biogenesis and leukocyte migration. The effect of TBTO on the latter process was confirmed using a CXCL12 chemotaxis assay.

Synergistic inflammatory effect of PM10 with mycotoxin deoxynivalenol on human lung epithelial cells

The presence of deoxynivalenol (DON), a mycotoxin produced by Fusarium species, has been reported worldwide in food and feedstuffs. Even though oral intake is the main route of exposure, DON inhalation is also of concern in workers and exposed population. Particulate matter (PM) is one of the most important causes of air quality detriment and it induces several adverse health effects. Therefore it is of primary importance to understand possible combined effects of DON and PM. The alveolar type II, A549, and the bronchial epithelial, BEAS-2B, cell lines were exposed for 24 h to different concentrations of DON (10-1000 ng/ml), PM10 (5 μg/cm(2), sampled in summer or winter season), and a combination of these pollutants. Cell death, interleukins release and cell cycle alteration were analysed; protein array technique was also applied to evaluate proteins activation related to MAP-kinases cascade. Our results demonstrate that low doses of PM and DON used alone have scarce toxic effects, while induce cytotoxicity and inflammation when used in combination. This observation outlines the importance of investigation on the combined effects of air pollutants for their possible outcomes on human health.

A novel Peptide-binding motifs inference approach to understand deoxynivalenol molecular toxicity

Deoxynivalenol (DON) is a type B trichothecene mycotoxin that is commonly detected in cereals and grains world-wide. The low-tolerated levels of this mycotoxin, especially in mono-gastric animals, reflect its bio-potency. The toxicity of DON is conventionally attributed to its ability to inhibit ribosomal protein biosynthesis, but recent advances in molecular tools have elucidated novel mechanisms that further explain DON’s toxicological profile, complementing the diverse symptoms associated with its exposure. This article summarizes the recent findings related to novel mechanisms of DON toxicity as well as how structural modifications to DON alter its potency. In addition, it explores feasible ways of expanding our understating of DON-cellular targets and their roles in DON toxicity, clearance, and detoxification through the utilization of computational biology approaches.

Cell cycle arrest and induction of apoptosis by cajanin stilbene acid from Cajanus cajan in breast cancer cells

BACKGROUND

The low abundant cajanin stilbene acid (CSA) from Pigeon Pea (Cajanus cajan) has been shown to kill estrogen receptor α positive cancer cells in vitro and in vivo. Downstream effects such as cell cycle and apoptosis-related mechanisms have not been analyzed yet.

MATERIAL AND METHODS

We analyzed the activity of CSA by means of flow cytometry (cell cycle distribution, mitochondrial membrane potential, MMP), confocal laser scanning microscopy (MMP), DNA fragmentation assay (apoptosis), Western blotting (Bax and Bcl-2 expression, caspase-3 activation) as well as mRNA microarray hybridization and Ingenuity pathway analysis.

RESULTS

CSA induced G2/M arrest and apoptosis in a concentration-dependent manner from 8.88 to 14.79 µM. The MMP broke down, Bax was upregulated, Bcl-2 downregulated and caspase-3 activated. Microarray profiling revealed that CSA affected BRCA-related DNA damage response and cell cycle-regulated chromosomal replication pathways.

CONCLUSION

CSA inhibited breast cancer cells by DNA damage and cell cycle-related signaling pathways leading to cell cycle arrest and apoptosis.

Successful validation of genomic biomarkers for human immunotoxicity in Jurkat T cells in vitro

Previously, we identified 25 classifier genes that were able to assess immunotoxicity using human Jurkat T cells. The present study aimed to validate these classifiers. For that purpose, Jurkat cells were exposed for 6 h to subcytotoxic doses of nine immunotoxicants, five non-immunotoxicants and four compounds for which human immunotoxicity has not yet been fully established. RNA was isolated and subjected to Fluidigm quantitative real time (qRT)-PCR analysis. The sensitivity, specificity and accuracy of the screening assay as based on the nine immunotoxicants and five non-immunotoxicants used in this study were 100%, 80% and 93%, respectively, which is better than the performance in our previous study. Only one compound was classified as false positive (benzo-e-pyrene). Of the four potential (non-)immunotoxicants, chlorantraniliprole and Hidrasec were classified immunotoxic and Sunset yellow and imidacloprid as non-immunotoxic. ToxPi analysis of the PCR data provided insight in the molecular pathways that were affected by the compounds. The immunotoxicants 2,3-dichloro-propanol and cypermethrin, although structurally different, affected protein metabolism and cholesterol biosynthesis and transport. In addition, four compounds, i.e. chlorpyrifos, aldicarb, benzo-e-pyrene and anti-CD3, affected genes in cholesterol metabolism and transport, protein metabolism and transcription regulation. qRT-PCR on eight additional genes coding for similar processes as defined in ToxPi analyzes, supported these results. In conclusion, the 25 immunotoxic classifiers performed very well in a screening with new non-immunotoxic and immunotoxic compounds. Therefore, the Jurkat screening assay has great promise to be applied within a tiered approach for animal free testing of human immunotoxicity.

Detection of the mechanism of immunotoxicity of cyclosporine A in murine in vitro and in vivo models

Transcriptomics in combination with in vitro cell systems is a powerful approach to unravel modes of action of toxicants. An important question is to which extent the modes of action as revealed by transcriptomics depend on cell type, species and study type (in vitro or in vivo). To acquire more insight into this, we assessed the transcriptomic effects of the immunosuppressive drug cyclosporine A (CsA) upon 6 h of exposure of the mouse cytotoxic T cell line CTLL-2, the thymoma EL-4 and primary splenocytes and compared these to the effects in spleens of mice orally treated with CsA for 7 days. EL-4 and CTLL-2 cells showed the highest similarities in response. CsA affected many genes in primary splenocytes that were not affected in EL-4 or CTLL-2. Pathway analysis demonstrated that CsA upregulated the unfolded protein response, endoplasmic reticulum stress and NRF2 activation in EL-4 cells, CTLL-2 cells and primary mouse splenocytes but not in mouse spleen in vivo. As expected, CsA downregulated cell cycle and immune response in splenocytes in vitro, spleens in vivo as well as CTLL-2 in vitro. Genes up- and downregulated in human Jurkat, HepG2 and renal proximal tubular cells were similarly affected in CTLL-2, EL-4 and primary splenocytes in vitro. In conclusion, of the models tested in this study, the known mechanism of immunotoxicity of CsA is best represented in the mouse cytotoxic T cell line CTLL-2. This is likely due to the fact that this cell line is cultured in the presence of a T cell activation stimulant (IL-2) making it more suitable to detect inhibitory effects on T cell activation.

Yessotoxin triggers ribotoxic stress

This work tests the hypothesis that the marine algal toxin yessotoxin (YTX) can trigger ribotoxic stress response in L6 and BC3H1 myoblast cells. YTX exposure at a concentration of 100 nM displays the characteristics of a ribotoxic stress response in such cells. The exposure leads to activation of the p38 mitogen-activated protein kinase, the stress-activated protein kinase c-jun, and the double-stranded RNA-activated protein kinase (PKR). YTX treatment also causes ribosomal RNA cleavage and inhibits protein synthesis. These observations support the idea that YTX can act as a ribotoxin.