Alteration of blood brain barrier permeability by T-2 toxin: Role of MMP-9 and inflammatory cytokines

Review of the Protective Effects of Selenium against T-2 Toxin-Induced Toxicity

The objective of the present study was to review the potential protective effects of Se against T-2 toxin-induced adverse effects in cartilage and other tissues as well as to discuss the potential molecular mechanisms by which Se counteracts T-2 toxicity. Laboratory studies demonstrate that Se attenuates T-2 toxin-induced chondrocyte death by inhibition of the mitochondrial pathway of apoptosis. Protective effects of Se against T-2 toxin-induced oxidative stress in chondrocytes are mediated by improvement of antioxidant selenoprotein expression, which is altered upon mycotoxin exposure. In addition to T-2 toxin-induced oxidative stress, Se treatment is associated with the inhibition of mycotoxin-induced chondrocyte ferroptosis. Along with prevention of chondrocyte damage, Se improves extracellular matrix (ECM) metabolism by the up-regulation of type II collagen and proteoglycans expression and inhibition of T-2 toxin-induced ECM degradation by matrix metalloproteinases. It is also noteworthy that part of the interactive effects between Se treatment and T-2 toxin exposure is mediated by epigenetic mechanisms, especially modulation of noncoding RNA expression. Recent evidence also shows that Se mitigates the toxic effects of the T-2 toxin in the liver, kidney, immune system, and other organs. Notably, a number of studies demonstrated that a Se deficiency aggravates the adverse effects of T-2 toxin exposure, supporting the notion of the protective effects of Se. However, the existing data were obtained in laboratory in vivo and in vitro models, and the potential therapeutic effects of Se supplementation in T-2 toxin-exposed human subjects have yet to be fully characterized.

Environmental mycotoxins: A potential etiological factor for neurodegenerative diseases?

Mycotoxins are potential environmental risk factors for neurodegenerative diseases. These toxins penetrate the central nervous system via a compromised blood-brain barrier, which may cause oxidative stress and neuroinflammation, these can also contribute to amyloid-beta (Aβ) plaque accumulation, Tau protein hyperphosphorylation, and neurofibrillary tangle formation. Mycotoxins also activate microglia, cause neuronal apoptosis, and disrupt central nervous system function. This study examines the evidence linking mycotoxin exposure to neurodegenerative disorders like Alzheimer's and Parkinson's diseases. We explore mechanisms such as oxidative stress, mitochondrial dysfunction, blood-brain barrier disruption, neuroinflammation, and direct neurotoxic effects. Epidemiological studies show regional variations in mycotoxin prevalence and corresponding neurodegenerative disease incidences, supporting this association. We also review current approaches to mitigate mycotoxin exposure and discuss the challenges and opportunities in developing strategies to prevent or slow neurodegenerative disease progression. This work highlights the need for increased awareness and research on mycotoxins as modifiable risk factors in neurological health.

Neurotoxicological Effects of Some Mycotoxins on Humans Health and Methods of Neuroprotection

Food contamination with mycotoxin-producing fungi increases the risk of many diseases, including neurological diseases closely related to the neurotoxicity of these toxins. Based on the latest literature data, we presented the association of common Fusarium mycotoxins with neurological diseases. Articles from 2001 to 2024 were analyzed. The mechanisms underlying the neurotoxicity of the described mycotoxins were presented. They are mainly related to the increase in oxidative stress in neuronal cells, which leads to higher levels of pro-inflammatory cytokines as IL-1β, IL-6 and TNF-α, enzymatic activity as GST, GPx, CAT and SOD and neurotransmitter dysfunction (5-HT, serotonin, dopamine and GABA). At the end of the article, based on the literature data, we attempted to present ways to mitigate mycotoxin neurotoxicity using mainly natural substances of plant origin. The data in this review focus on the Fusarium mycotoxins most frequently found in food and will be useful as comparative information for future studies. It is important to conduct further studies to mitigate the neurotoxic effects of Fusarium mycotoxins in order to reduce the development of diseases of the nervous system.

Human next-generation risk assessment of trichothecene toxicity

Trichothecenes are naturally occurring chemicals, produced by fungi, that can be found in contaminated crops. Trichothecenes have the potential to indirectly damage DNA and exacerbate genotoxic effects of genotoxicants. However, genotoxicity data for most trichothecenes are limited and data gaps remain. Here we use the γH2AX/pH3 assay to evaluate DNA damage in vitro of 13 trichothecenes. Three human cell lines (SH-SY5Y, ACHN, and HepG2) were exposed to each trichothecene (0.001-100 μM) to assess toxicity as models for the brain, kidney, and liver, respectively. Concentration-dependent induction of DNA damage, illustrated by γH2AX induction, was observed for all trichothecenes. In vitro-in vivo extrapolation (IVIVE) modeling was employed to support in vivo equivalent potency ranking and screen for risk potential. Diacetoxyscirpenol, T-2, and HT-2 had the highest genotoxic potency, notably in SH-SY5Y cells. Administered equivalent doses (AEDs) derived from IVIVE were compared against exposure data from French total diet studies to assess risk potential. AEDs derived for T-2 and HT-2 from the SH-SY5Y model were within 100-fold of exposure levels for infants aged one year or less. Overall, the potential for trichothecenes to damage DNA and higher exposures in infants highlights the need to investigate the cumulative effects across the broader trichothecene family.

The role of BTG2/PI3K/AKT pathway-mediated microglial activation in T-2 toxin-induced neurotoxicity

T-2 toxin is one of the mycotoxins widely distributed in human food and animal feed. Our recent work has shown that microglial activation may contribute to T-2 toxin-induced neurotoxicity. However, the molecular mechanisms involved need to be further clarified. To address this, we employed high-throughput transcriptome sequencing and found altered B cell translocation gene 2 (BTG2) expression levels in microglia following T-2 toxin treatment. It has been shown that altered BTG2 expression is involved in a range of neurological pathologies, but whether it's involved in the regulation of microglial activation is unclear. The aim of this study was to investigate the role of BTG2 in T-2 toxin-induced microglial activation. The results of animal experiments showed that T-2 toxin caused neurobehavioral disorders and promoted the expression of microglial BTG2 and pro-inflammatory activation of microglia in hippocampus and cortical, while microglial inhibitor minocycline inhibited these changes. The results of in vitro experiments showed that T-2 toxin enhanced BTG2 expression and pro-inflammatory microglial activation, and inhibited BTG2 expression weakened T-2 toxin-induced microglial activation. Moreover, T-2 toxin activated PI3K/AKT and its downstream NF-κB signaling pathway, which could be reversed after knock-down of BTG2 expression. Meanwhile, the PI3K inhibitor LY294002 also blocked this process. Therefore, BTG2 may be involved in T-2 toxin's ability to cause microglial activation through PI3K/AKT/NF-κB pathway.

Endocrine disrupting effects on morphological synaptic plasticity

Neural regulation of the homeostasis depends on healthy synaptic function. Adaptation of synaptic functions to physiological needs manifests in various forms of synaptic plasticity (SP), regulated by the normal hormonal regulatory circuits. During the past several decades, the hormonal regulation of animal and human organisms have become targets of thousands of chemicals that have the potential to act as agonists or antagonists of the endogenous hormones. As the action mechanism of these endocrine disrupting chemicals (EDCs) came into the focus of research, a growing number of studies suggest that one of the regulatory avenues of hormones, the morphological form of SP, may well be a neural mechanism affected by EDCs. The present review discusses known and potential effects of some of the best known EDCs on morphological synaptic plasticity (MSP). We highlight molecular mechanisms altered by EDCs and indicate the growing need for more research in this area of neuroendocrinology.

Neurotoxic mechanisms of mycotoxins: Focus on aflatoxin B1 and T-2 toxin

Aflatoxin B1 (AFB1) and T-2 toxin are commonly found in animal feed and stored grain, posing a serious threat to human and animal health. Mycotoxins can penetrate brain tissue by compromising the blood-brain barrier, triggering oxidative stress and neuroinflammation, and leading to oxidative damage and apoptosis of brain cells. The potential neurotoxic mechanisms of AFB1 and T-2 toxin were discussed by summarizing the relevant research reports from the past ten years. AFB1 and T-2 toxin cause neuronal damage in the cerebral cortex and hippocampus, leading to synaptic transmission dysfunction, ultimately impairing the nervous system function of the body. The toxic mechanism is related to excessive reactive oxygen species (ROS), oxidative stress, mitochondrial dysfunction, apoptosis, autophagy, and an exaggerated inflammatory response. After passing through the blood-brain barrier, toxins can directly affect glial cells, alter the activation state of microglia and astrocytes, thereby promoting brain inflammation, disrupting the blood-brain barrier, and influencing the synaptic transmission process. We discussed the diverse effects of various concentrations of toxins and different modes of exposure on neurotoxicity. In addition, toxins can also cross the placental barrier, causing neurotoxic symptoms in offspring, as demonstrated in various species. Our goal is to uncover the underlying mechanisms of the neurotoxicity of AFB1 and T-2 toxin and to provide insights for future research, including investigating the impact of mycotoxins on interactions between microglia and astrocytes.

HIF-1α is a "brake" in JNK-mediated activation of amyloid protein precursor and hyperphosphorylation of tau induced by T-2 toxin in BV2 cells

Mycotoxins have been shown to activate multiple mechanisms that may potentially lead to the progression of Alzheimer's disease (AD). Overexpression/aberrant cleavage of amyloid precursor protein (APP) and hyperphosphorylation of tau (P-tau) is hallmark pathologies of AD. Recent advances suggest that the neurotoxic effects of mycotoxins involve c-Jun N-terminal kinase (JNK) and hypoxia-inducible factor-1α (HIF-1α) signaling, which are closely linked to the pathogenesis of AD. Due to the high toxicity and broad contamination of T-2 toxin, we assessed how T-2 toxin exposure alters APP and P-tau formation in BV2 cells and determined the underlying roles of HIF-1α and JNK signaling. The findings revealed that T-2 toxin stimulated the expression of HIF-1α and hypoxic stress factors in addition to increasing the expression of APP and P-tau. Additionally, HIF-1α acted as a "brake" on the induction of APP and P-tau expression by negatively regulating these proteins. Notably, T-2 toxin activated JNK signaling, which broke this "brake" to promote the formation of APP and P-tau. Furthermore, the cytoskeleton was an essential target for T-2 toxin to exert cytotoxicity, and JNK/HIF-1α participated in this damage. Collectively, when the T-2 toxin induces the production of APP and P-tau, JNK might interfere with HIF-1α's protective function. This study will provide clues for further research on the neurotoxicity of mycotoxins.

Ochratoxin A stimulates release of IL-1β, IL-18 and CXCL8 from cultured human microglia

Exposure to mycotoxins has been associated with the development of neuropsychiatric symptoms and Ochratoxin A (OTA) has emerged as one of the main mycotoxins associated with neurotoxicity. However, the mechanism via OTA exerts its neurotoxic effects is not well understood, especially the importance of activated microglia and their contribution to neuroinflammation. Here we report the effect of OTA on cultured immortalized human microglia-SV40, as compared to the effect of neurotensin (NT) and lipopolysaccharide (LPS) used as "positive" triggers. OTA (1, 10 and 100 nM for 24 hrs) stimulated microglia to release in the supernatant fluids statistically significant amounts of IL-1β, IL-18 and CXCL8 assayed with ELISA. Preventing or inhibiting OTA-stimulated activation of microglia by luteolin could be an important way to limit mycotoxin-induced neuroinflammation and improve associated neuropsychiatric diseases.

Review of neurotoxicity of T-2 toxin

T-2 toxin is a representative trichothecene that is widely detected in corn, wheat and other grain feeds. T-2 toxin has stable physical and chemical properties, making it difficult to remove from food and feed. Hence, T-2 toxin has become an unavoidable pollutant in food for humans and animals. T-2 toxin can enter brain tissue by crossing the blood-brain barrier and leads to congestion, swelling and even apoptosis of neurons. T-2 toxin poisoning can directly lead to clinical symptoms (anti-feeding reaction and decline of learning and memory function in humans and animals). Maternal T-2 toxin exposure also exerted toxic effects on the central nervous system of offspring. Oxidative stress is the core neurotoxicity mechanism underlying T-2 toxin poison. Oxidative stress-mediated apoptosis, mitochondrial oxidative damage and inflammation are all involved in the neurotoxicity induced by T-2 toxin. Thus, alleviating oxidative stress has become a potential target for relieving the neurotoxicity induced by T-2 toxin. Future efforts should be devoted to revealing the neurotoxic molecular mechanism of T-2 toxin and exploring effective therapeutic drugs to alleviate T-2 toxin-induced neurotoxicity.

Daucosterol confers protection against T-2 toxin induced blood-brain barrier toxicity through the PGC-1α-mediated defensive response in vitro and in vivo

T-2 toxin is a common environmental pollutant and contaminant in food and animal feed that represents a great challenge to human and animal' health throughout the world. Using natural compounds to prevent the detrimental effects of T-2 toxin represents an attractive strategy. Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) is a critical regulator in various cellular processes. Recently, PGC-1α activation has been reported to confer protection against neurological injuries. We aimed to identify a potent PGC-1α activator from plants as a chemopreventive compound and to demonstrate the efficacy of the compound in attenuating T-2 toxin-induced blood-brain barrier (BBB) toxicity. We identified daucosterol, which binds directly to the 71-74 (-1100 to -1000 bp) position of the second promoter of human PGC-1α by hydrogen bonding. An in vitro and in vivo T-2 toxin induced BBB injury model revealed that this compound can protect against this injury by increasing transepithelial/transendothelial electrical resistance, reducing sodium fluorescein (NaF) infiltration and increasing the expression of tight junction-related proteins (zonula occludens-1 (ZO-1), occludin (OCLN), claudin-5 (CLDN5)) expression. In conclusion, we identified daucosterol as representing a novel of PGC-1α activators and illustrated the mechanism of specific binding site. Furthermore, we have demonstrated the feasibility of using natural compounds targeting PGC-1α as a therapeutic approach to protect humans from environmental insults that may occur daily such as lipopolysaccharide.

T-2 Toxin Induces Apoptotic Cell Death and Protective Autophagy in Mouse Microglia BV2 Cells

T-2 toxin exposure could cause neurotoxicity; however, the precise molecular mechanisms remain unclear. In the present study, we investigated T-2 toxin-induced cytotoxicity and underlying molecular mechanisms using a mouse microglia BV2 cell line. The results show that T-2 toxin treatment-induced cytotoxicity of BV2 cells was dose- and time-dependent. Compared to the control, T-2 toxin treatment at 1.25–5 ng/mL significantly increased reactive oxygen species (ROS) production and triggered oxidative stress. T-2 toxin treatment also caused mitochondrial dysfunction in BV2 cells, which was evidenced by decreased mitochondrial transmembrane potential, upregulated expression of Bax protein, and decreased expression of Bcl-2 protein. Meanwhile, T-2 toxin treatment upregulated the expression of cleaved-caspase-3, cleaved-PARP-1 proteins, and downregulated the expression of HO-1 and nuclear Nrf2 proteins, finally inducing cell apoptosis in BV2 cells. N-acetylcysteine (NAC) supplementation significantly attenuated T-2 toxin-induced cytotoxicity. Moreover, T-2 toxin treatment activated autophagy and upregulated autophagy flux, and the inhibition of autophagy significantly promoted T-2 toxin-induced cell apoptosis. Taken together, our results reveal that T-2 toxin-induced cytotoxicity in BV2 cells involves the production of ROS, the activation of the mitochondrial apoptotic pathway, and the inhibition of the Nrf2/HO-1 pathway. Our study offers new insight into the underlying molecular mechanisms in T-2 toxin-mediated neurotoxicity.

Betulinic acid attenuates cognitive dysfunction, oxidative stress, and inflammation in a model of T-2 toxin-induced brain damage

T-2 toxin is a mycotoxin that has harmful effects on the immune system and cognitive function. Betulinic acid (BA) is a plant-derived pentacyclic lupane-type triterpenoid which possesses a wide spectrum of bioactivities. The study was aimed to explore whether BA has a protective effect on cognitive impairment and oxidative stress caused by T-2 toxin. BA was suspended in 1% soluble starch by continuous intragastric administration for 14 days, then the brain damage in mice was induced by a single intraperitoneal injection of T-2 toxin (4 mg/kg). It was found that BA alleviated the reduction of discrimination index in T-2 toxin-treated mice, and enhanced dopamine (DA), 5-hydroxytryptamine (5-HT), and acetylcholine (ACH) levels of brain neurotransmitter. Meanwhile, BA pretreatment ameliorated oxidative stress through increase of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and glutathione (GSH) levels, and inhibition of the generation of reactive oxygen species (ROS) and malondialdehyde (MDA) in the brain of mice exposed to T-2 toxin. Moreover, BA reduced brain hemorrhage and ecchymosis, improved the mitochondrial morphology, enriched the number of organelles, and inhibited cell apoptosis in brain challenged with T-2 toxin. Furthermore, BA inhibited mRNA expression of pro-inflammatory cytokines such as interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α) as well as enhanced mRNA expression of anti-inflammatory cytokine such as IL-10 in the brain of T-2 toxin-triggered mice. Therefore, BA could improve the cognitive function, enhance the antioxidant capacity, and inhibit the secretion of proinflammatory cytokines in brain, thereby playing a preventive and protective role against brain damage caused by T-2 toxin.

Microglial Activation Damages Dopaminergic Neurons through MMP-2/-9-Mediated Increase of Blood-Brain Barrier Permeability in a Parkinson's Disease Mouse Model

Chronic neuroinflammation has been considered to be involved in the progressive dopaminergic neurodegeneration in Parkinson’s disease (PD). However, the mechanisms remain unknown. Accumulating evidence indicated a key role of the blood–brain barrier (BBB) dysfunction in neurological disorders. This study is designed to elucidate whether chronic neuroinflammation damages dopaminergic neurons through BBB dysfunction by using a rotenone-induced mouse PD model. Results showed that rotenone dose-dependently induced nigral dopaminergic neurodegeneration, which was associated with increased Evans blue content and fibrinogen accumulation as well as reduced expressions of zonula occludens-1 (ZO-1), claudin-5 and occludin, three tight junction proteins for maintaining BBB permeability, in mice, indicating BBB disruption. Rotenone also induced nigral microglial activation. Depletion of microglia or inhibition of microglial activation by PLX3397 or minocycline, respectively, greatly attenuated BBB dysfunction in rotenone-lesioned mice. Mechanistic inquiry revealed that microglia-mediated activation of matrix metalloproteinases-2 and 9 (MMP-2/-9) contributed to rotenone-induced BBB disruption and dopaminergic neurodegeneration. Rotenone-induced activation of MMP-2/-9 was significantly attenuated by microglial depletion and inactivation. Furthermore, inhibition of MMP-2/-9 by a wide-range inhibitor, SB-3CT, abrogated elevation of BBB permeability and simultaneously increased tight junctions expression. Finally, we found that microglial depletion and inactivation as well as inhibition of MMP-2/-9 significantly ameliorated rotenone-elicited nigrostriatal dopaminergic neurodegeneration and motor dysfunction in mice. Altogether, our findings suggested that microglial MMP-2/-9 activation-mediated BBB dysfunction contributed to dopaminergic neurodegeneration in rotenone-induced mouse PD model, providing a novel view for the mechanisms of Parkinsonism.

Microglia at the Crossroads of Pathogen-Induced Neuroinflammation

Microglia are the resident tissue macrophages of the central nervous system (CNS). Recent findings point out that in the steady state the major role of microglia, is to instruct and regulate the correct function of the neuronal networks and different components of the neurovascular unit in the adult CNS, while providing immune surveillance. Paradoxically, during CNS infection immune activation of microglia generates an inflammatory milieu that contributes to the clearance of the pathogen but can, in the process, harm nearby cells of CNS. Most of the knowledge about the harmful effects of activated microglia on CNS has arisen from studies on neurodegenerative diseases. In this review we will focus on the beneficial role and detrimental functions of microglial cells on the neighboring cells of the CNS upon infection.

High fat diet-induced brain damaging effects through autophagy-mediated senescence, inflammation and apoptosis mitigated by ginsenoside F1-enhanced mixture

Background

Herbal medicines are popular approaches to capably prevent and treat obesity and its related diseases. Excessive exposure to dietary lipids causes oxidative stress and inflammation, which possibly induces cellular senescence and contribute the damaging effects in brain. The potential roles of selective enhanced ginsenoside in regulating high fat diet (HFD)-induced brain damage remain unknown.

Methods

The protection function of Ginsenoside F1-enhanced mixture (SGB121) was evaluated by in vivo and in vitro experiments. Human primary astrocytes and SH-SY5Y cells were treated with palmitic acid conjugated Bovine Serum Albumin, and the effects of SGB121 were determined by MTT and lipid uptake assays. For in vivo tests, C57BL/6J mice were fed with high fat diet for 3 months with or without SGB121 administration. Thereafter, immunohistochemistry, western blot, PCR and ELISA assays were conducted with brain tissues.

Results and conclusion

SGB121 selectively suppressed HFD-induced oxidative stress and cellular senescence in brain, and reduced subsequent inflammation responses manifested by abrogated secretion of IL-6, IL-1β and TNFα via NF-κB signaling pathway. Interestingly, SGB121 protects against HFD-induced damage by improving mitophagy and endoplasmic reticulum-stress associated autophagy flux and inhibiting apoptosis. In addition, SGB121 regulates lipid uptake and accumulation by FATP4 and PPARα. SGB121 significantly abates excessively phosphorylated tau protein in the cortex and GFAP activation in corpus callosum. Together, our results suggest that SGB121 is able to favor the resistance of brain to HFD-induced damage, therefore provide explicit evidence of the potential to be a functional food.

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High fat diet induces oxidative stress and subsequent cellular senescence in mice brain.

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High fat diet induces pathologies in cortex and GFAP activation in corpus callosum.

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Ginsenoside F1-enhanced mixture ameliorates damaging effect by modulating autophagy flux and inflammation.

Food-Origin Mycotoxin-Induced Neurotoxicity: Intend to Break the Rules of Neuroglia Cells

Mycotoxins are key risk factors in human food and animal feed. Most of food-origin mycotoxins could easily enter the organism and evoke systemic toxic effects, such as aflatoxin B1 (AFB1), ochratoxin A (OTA), T-2 toxin, deoxynivalenol (DON), zearalenone (ZEN), fumonisin B1 (FB1), and 3-nitropropionic acid (3-NPA). For the last decade, the researches have provided much evidences in vivo and in vitro that the brain is an important target organ on mycotoxin-mediated neurotoxic phenomenon and neurodegenerative diseases. As is known to all, glial cells are the best regulator and defender of neurons, and a few evaluations about the effects of mycotoxins on glial cells such as astrocytes or microglia have been conducted. The fact that mycotoxin contamination may be a key factor in neurotoxicity and glial dysfunction is exactly the reason why we reviewed the activation, oxidative stress, and mitochondrial function changes of glial cells under mycotoxin infection and summarized the mycotoxin-mediated glial cell proliferation disorders, death pathways, and inflammatory responses. The purpose of this paper is to analyze various pathways in which common food-derived mycotoxins can induce glial toxicity and provide a novel perspective for future research on the neurodegenerative diseases.

Celastrol protects against early brain injury after subarachnoid hemorrhage in rats through alleviating blood-brain barrier disruption and blocking necroptosis

BACKGROUND

Subarachnoid hemorrhage (SAH) is a life-threatening disease worldwide, and effective pharmaceutical treatment is still lacking. Celastrol is a plant-derived triterpene which showed neuroprotective potential in several types of brain insults. This study aimed to investigate the effects of celastrol on early brain injury (EBI) after SAH.

METHODS

A total of sixty-one male Sprague-Dawley rats were used in this study. Rat SAH endovascular perforation model was established to mimic the pathological changes of EBI after SAH. Multiple methods such as 3.0T MRI scanning, immunohistochemistry, western blotting and propidium iodide (PI) labeling were used to explore the therapeutic effects of celastrol on SAH.

RESULTS

Celastrol treatment attenuated SAH-caused brain swelling, reduced T2 lesion volume and ventricular volume in MRI scanning, and improved overall neurological score. Albumin leakage and the degradation of tight junction proteins were also ameliorated after celastrol administration. Celastrol protected blood-brain bairrer integrity through inhibiting MMP-9 expression and anti-neuroinflammatory effects. Additionally, necroptosis-related proteins RIP3 and MLKL were down-regulated and PI-positive cells in the basal cortex were less in the celastrol-treated SAH group than that in untreated SAH group.

CONCLUSIONS

Celastrol exhibits neuroprotective effects on EBI after SAH and deserves to be further investigated as an add-on pharmaceutical therapy.

Protective Effect of Organic Selenium on Oxidative Damage and Inflammatory Reaction of Rabbit Kidney Induced by T-2 Toxin

T-2 toxin is a member of a class of mycotoxins produced by a variety of Fusarium species under appropriate temperature and humidity conditions and is a common contaminant in food and feedstuffs of cereal origin. Selenium is an indispensable element in animals, regulates a variety of biological functions of the body, and can antagonize metal and mycotoxin poisoning to a certain extent. However, the effect of selenium on kidney injury induced by T-2 toxin has not been reported. In this study, 50 New Zealand rabbits were divided into 5 groups (the control group, T-2 toxin group, low-dose Se + T-2 toxin group, medium-dose Se + T-2 toxin group, and high-dose Se + T-2 toxin group). Rabbits were examined after oral administration of different doses of selenomethionine (SeMet) for 21 days and after perfusion with 0.4 mg/kg T-2 toxin (or the same dose of olive oil in the control group) for 5 days. We found that T-2 toxin induced kidney function damage and increased the levels of ROS and the contents of inflammatory factors. Renal structure was pathologically damaged. However, we found that after pretreatment with 0.2 mg/kg SeMet, oxidative stress, the inflammatory response, and pathological damage induced by T-2 toxin were attenuated. The results indicate that a low dose (0.2 mg/kg) of SeMet effectively reversed T-2 toxin-induced kidney injury in rabbits.

Treatment and protective effects of metalloproteinase inhibitors alone and in combination with N-Acetyl cysteine plus vitamin E in rats exposed to aflatoxin B1

This study was conducted to investigate the effects of matrix metalloproteinase (MMP) inhibitors dexamethasone and minocycline administrations -both single and in combination with N-acetylcysteine (NAC) and vitamin E-on the tissue distribution and lethal dose (LD)50 of aflatoxin (AF)B1 in rats. We performed this study on male Wistar rats (8-10 weeks) in two phases. In the first phase, rats were administered dexamethasone (5 and 20 mg/kg) and minocycline (45 and 90 mg/kg), both as single treatments and in combination with NAC (200 mg/kg) and vitamin E (600 mg/kg); these treatments followed AFB1 administration (2 mg/kg). In the second phase, the therapeutic effect value (TEV) was calculated to determine the treatment effect on the LD50 level of AFB1. The tissue affinity of AFB1 from high to low was liver, kidney, intestine, brain, heart, spleen, lung, testis, and vitreous humor, respectively. Dexamethasone at the 20 mg/kg dose significantly reduced AFB1 concentrations in the plasma and the other tissues, except for the vitreous humor. The effects of minocycline on the plasma and tissue concentrations of AFB1 varied by dose and tissue. The combinations of dexamethasone or minocycline with NAC and vitamin E increased the AFB1 concentrations in the plasma and all tissues, except for vitreous humor and liver. In male rats, the LD50 value of AFB1 was 11.86 mg/kg. The TEV of dexamethasone (20 mg/kg) was calculated to be 1.5. Dexamethasone can be administered in repeated doses at ≥20 mg/kg to increase survival in AFB1 poisoning.

Effects of dietary T-2 toxin on gut health and gut microbiota composition of the juvenile Chinese mitten crab (Eriocheir sinensis)

The current study aims to investigate the effects of dietary T-2 toxin on the intestinal health and microflora in the juvenile Chinese mitten crab (Eriocheir sinensis) with an initial weight 2.00 ± 0.05 g. Juvenile crabs were fed with experimental diets supplemented with T-2 toxin at 0 (control), 0.6 (T1 group), 2.5 (T2 group) and 5.0 (T3 group) mg/kg diet for 8 weeks. Dietary T-2 toxin increased the malondialdehyde (MDA) content and the expression of Kelch-like ECH-associated protein 1 (keap1) gene while the expression of cap 'n' collar isoform C (CncC) decreased in the intestine. The activities of glutathione peroxidase (GSH-Px) and total anti-oxidation capacity (T-AOC) in the intestine increased only in the lower dose of dietary T-2. Dietary T-2 toxin significantly increased the mRNA expression of caspase-3, caspase-8, Bax and mitogen-activated protein kinase (MAPK) genes and the ratio of Bax to Bcl-2 accompanied with a reduction of Bcl-2 expression. Furthermore, T-2 toxin decreased the mRNA levels of antimicrobial peptides (AMPs), peritrophic membrane (PM1 and PM2) and immune regulated nuclear transcription factors (Toll-like receptor: TLR, myeloid differentiation primary response gene 88: Myd88, relish and lipopolysaccharide-induced TNF-α factor: LITAF). The richness and diversity of the gut microbiota were also affected by dietary T-2 toxin in T3 group. The similar dominant phyla in the intestine of the Chinese mitten crab in the control and T3 groups were found including Bacteroidetes, Firmicutes, Tenericutes and Proteobacteria. Moreover, the inclusion of dietary T-2 toxin of 4.6 mg/kg significantly decreased the richness of Bacteroidetes and increased the richness of Firmicutes, Tenericutes and Proteobacteria in the intestine. At the genus level, Dysgonomonas and Romboutsia were more abundant in T3 group than those in the control. However, the abundances of Candidatus Bacilloplasma, Chryseobacterium and Streptococcus in T3 group were lower than those in the control. This study indicates that T-2 toxin could cause oxidative damage and immunosuppression, increase apoptosis and disturb composition of microbiota in the intestine of Chinese mitten crab.

Molecular Aspects of Mycotoxins-A Serious Problem for Human Health

Mycotoxins are toxic fungal secondary metabolities formed by a variety of fungi (moulds) species. Hundreds of potentially toxic mycotoxins have been already identified and are considered a serious problem in agriculture, animal husbandry, and public health. A large number of food-related products and beverages are yearly contaminated by mycotoxins, resulting in economic welfare losses. Mycotoxin indoor environment contamination is a global problem especially in less technologically developed countries. There is an ongoing effort in prevention of mould growth in the field and decontamination of contaminated food and feed in order to protect human and animal health. It should be emphasized that the mycotoxins production by fungi (moulds) species is unavoidable and that they are more toxic than pesticides. Human and animals are exposed to mycotoxin via food, inhalation, or contact which can result in many building-related illnesses including kidney and neurological diseases and cancer. In this review, we described in detail the molecular aspects of main representatives of mycotoxins, which are serious problems for global health, such as aflatoxins, ochratoxin A, T-2 toxin, deoxynivalenol, patulin, and zearalenone.

The neurotoxicity of trichothecenes T-2 toxin and deoxynivalenol (DON): Current status and future perspectives

During the last decade, the neurotoxicity of the trichothecenes T-2 toxin and deoxynivalenol (DON) has been a major concern, and many important findings have been reported on this topic. Through a summary of relevant research reports in recent years, we discuss the potential neurotoxic mechanisms of T-2 toxin and DON. In neuronal cells, T-2 toxin induces mitochondrial dysfunction and oxidative stress through a series of signalling pathways, including Nrf2/HO-1 and p53. This toxin crosses the blood-brain barrier (BBB) by altering permeability and induces oxidative stress responses, including ROS generation, lipid peroxidation, and protein carbonyl formation. Cellular metabolites (for example, HT-2 toxin) further promote neurotoxic effects. The type B trichothecene DON induces neuronal cell apoptosis via the MAPK and mitochondrial apoptosis pathways. This molecule induces inflammation of the central nervous system, increasing the expression of proinflammatory molecules. DON directly affects brain neurons and glial cells after passing through the BBB and affects the vitality and function of astrocytes and microglia. Exposure to trichothecenes alters brain dopamine levels, decreases ganglion area, and further induces brain damage. In this review, we mainly discuss the neurotoxicity of T-2 toxin and DON. However, our main goal was to reveal the potential mechanism(s) and offer new topics, including the potential of hypoxia-inducible factors, immune evasion, and exosomes, for future research in this context. This review should help elucidate the neurotoxic mechanism of trichothecenes and provides some potential inspiration for the follow-up study of neurotoxicity of mycotoxins.

Protective effect of selenomethionine on intestinal injury induced by T- 2 toxin

T-2 toxin is the most toxic as a type A trichothecenes, which could contaminate grains, especially in wheat and corn. It can cause immune suppression, neurotoxicity, the apoptosis of cells and even induce tumorigenesis. Recent studies have indicated that selenium (Se) have protective effect against mycotoxins-induced toxicity. The present studies was designed to investigate the protective role of Selenomethionine (SeMet) on T-2 toxin-induced toxicity in rabbit's jejunum. 50 New Zealand rabbits were divided into five group (Control group, T-2 group, low-dose Se + T-2 group, medium-dose + T-2 group and high-dose Se + T-2 group). New Zealand rabbits were orally administered with SeMet (0.2, 0.4 and 0.6 mg/kg, Adding diet) for 21 days. On 17th days, each group began to take 0.4 mg/kg of T-2 toxin orally every day for 5 days. We found that rabbit exposed to T-2 toxin could increase the levels of ROS, and decrease activities of antioxidant enzymes and the expression of Occludin and ZO-1. In addition, T-2 toxin could trigger jejunal inflammatory response and enhance the expression of IL-1β, IL-6 and TNF-α. After SeMet pretreatment, our results indicated that Se attenuated the T-2 toxin-induced oxidative stress, decreasing the level of ROS, MDA and enhancing the activity of SOD and GSH-Px. Moreover, SeMet can alleviate jejunal inflammatory response, and protect the integrity of the intestinal barrier through up-regulating the expression of ZO-1 and Occludin. In the present research, supplementation of 0.2 mg/kg SeMet in the diet could effectively alleviate the T-2 toxin poisoning in rabbits.

MiR-155-5p plays as a "janus" in the expression of inflammatory cytokines induced by T-2 toxin

Although many studies have shown that inflammatory response plays a crucial role in the various toxic effects of T-2 toxin, there are relatively few reports on the mechanism of this phenomenon. Meanwhile, accumulating evidence has shown that miR-155-5p is activated in the inflammatory response. As molecular pathways and mechanisms involved in T-2 toxin-induced inflammatory response are poorly elucidated, we assessed whether miR-155-5p is involved in the inflammation effects mediated by T-2 toxin. Treatment of RAW264.7 cells with T-2 toxin (14 nM and 12 h) resulted in inflammatory response and associated with alteration of the gene expression signature of miR-155-5p. Knockdown or overexpression of miR-155-5p both indicated that miR-155-5p positively regulated the expression of the inflammation factors. Moreover, bioinformatics prediction and luciferase assay indicated that atg3 and rheb are targets of miR-155-5p. However, atg3 and SOCS1 play positive roles in the inflammatory response regulated by miR-155-5p, while rheb plays a negative role. In addition, the in vivo study showed that single administration of T-2 toxin in mice enhances spleen immune response, which was accompanied by an overexpression of miR-155-5p. These findings indicate that miR-155-5p might have an important role associated with the inflammatory response induced by T-2 toxin. In conclusion, a dual character of miR-155-5p in inflammation response was revealed, which might exist in other reactions in which miR-155-5p is involved.

Endocrine Disruptors Induced Distinct Expression of Thyroid and Estrogen Receptors in Rat versus Mouse Primary Cerebellar Cell Cultures

The endocrine system of animals consists of fine-tuned self-regulating mechanisms that maintain the hormonal and neuronal milieu during tissue development. This complex system can be influenced by endocrine disruptors (ED)—substances that can alter the hormonal regulation even in small concentrations. By now, thousands of substances—either synthesized by the plastic, cosmetic, agricultural, or medical industry or occurring naturally in plants or in polluted groundwater—can act as EDs. Their identification and testing has been a hard-to-solve problem; Recent indications that the ED effects may be species-specific just further complicated the determination of biological ED effects. Here we compare the effects of bisphenol-A, zearalenone, and arsenic (well-known EDs) exerted on mouse and rat neural cell cultures by measuring the differences of the ED-affected neural estrogen- and thyroid receptors. EDs alters the receptor expression in a species-like manner detectable in the magnitude as well as in the nature of biological responses. It is concluded that the interspecies differences (or species specificity) in ED effects should be considered in the future testing of ED effects.

T-2 toxin neurotoxicity: role of oxidative stress and mitochondrial dysfunction

Mycotoxins are highly diverse secondary metabolites produced in nature by a wide variety of fungi. Mycotoxins cause animal feed and food contamination, resulting in mycotoxicosis. T-2 toxin is one of the most common and toxic trichothecene mycotoxins. For the last decade, it has garnered considerable attention due to its potent neurotoxicity. Worryingly, T-2 toxin can cross the blood-brain barrier and accumulate in the central nervous system (CNS) to cause neurotoxicity. This review covers the current knowledge base on the molecular mechanisms of T-2 toxin-induced oxidative stress and mitochondrial dysfunction in the CNS. In vitro and animal data have shown that induction of reactive oxygen species (ROS) and oxidative stress plays a critical role during T-2 toxin-induced neurotoxicity. Mitochondrial dysfunction and cascade signaling pathways including p53, MAPK, Akt/mTOR, PKA/CREB and NF-κB contribute to T-2 toxin-induced neuronal cell death. T-2 toxin exposure can also result in perturbations of mitochondrial respiratory chain complex and mitochondrial biogenesis. T-2 toxin exposure decreases the mitochondria unfolded protein response and dampens mitochondrial energy metabolism. Antioxidants such as N-acetylcysteine (NAC), activation of Nrf2/HO-1 and autophagy have been shown to provide a protective effect against these detrimental effects. Clearly, translational research and the discovery of effective treatment strategies are urgently required against this common food-borne threat to human health and livestock.

Proteasome serves as pivotal regulator in Angiostrongylus cantonensis-induced eosinophilic meningoencephalitis

Proteasome primarily degrades the unneeded or damaged proteins by proteolysis. Disruption of the brain barrier and its resulting meningoencephalitis caused by Angiostrongylus cantonensis are important pathological events in non-permissive hosts. In this study, the results showed upregulated proteasome during A. cantonensis infection. Occludin degradation and matrix metalloproteinase-9 (MMP-9) activity were significantly increased in infected mice than in uninfected mice. Moreover, confocal immunoflourescence microscopy showed that occludin was co-localized with MMP-9. The infected-mice were treated with proteasomal activity inhibitor MG132 by 1.5 and 3.0 mg/kg/day, which resulted in significantly reduced protein levels of phosphorylated IκBα (P<0.05) compared with the untreated control. The phosphorylated nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) showed similar result. In addition, MMP-9 activity and occludin degradation were reduced because of MG132 treatment. These results suggested that the proteasome in A. cantonensis infection degraded phosphorylated IκBα, modulated phosphorylated NF-κB, and then regulated the activation of MMP-9 and occludin degradation. Proteasome alterations were presented in eosinophilic meningitis of BALB/c mice and may contribute to the pathophysiology of eosinophilic meningitis by increasing occludin degradation. This molecule would serve as pivotal regulator in A. cantonensis-induced eosinophilic meningoencephalitis.

DNA methylation is involved in pro-inflammatory cytokines expression in T-2 toxin-induced liver injury

Currently, T-2 toxin has been reported to cause liver toxicity with the effects of oxidative stress and inflammation; however, the underlying mechanism of T-2 toxin-induced liver injury is not fully understood. Increasing lines of evidence show that DNA methylation affects the expression of inflammatory cytokine, and plays a crucial role in autoimmune diseases. Nevertheless, the potential role of DNA methylation in the hepatotoxicity of T-2 toxin has not been explored. In this study, female Wistar rats were given a single dose of T-2 toxin at 2 mg/kg b.w. and were sacrificed at 1, 3 and 7 days post-exposure. In vitro, a normal rat liver cell line (BRL) was exposed to different concentrations of T-2 toxin. Histopathological analysis was used to investigate damage to the liver, which was detected at the molecular level by RT-PCR, Western blot and immunohistochemical assays, methylation-specific PCR (MSP), bisulfite sequencing (BSP), and flow cytometry. The results showed that T-2 toxin significantly increased the levels of DNA methyltransferases (DNMT1, DNMT3A), which were mainly concentrated at the site of liver injury. The 5-methylcytosine (5-mC) level of genomic DNA was also raised in T-2 toxin-treated rat livers. The expression of inflammatory cytokines (IL-6, IL-1β, IL-11, IL-1α, and TNF-α) increased both in vivo and in vitro under T-2 toxin treatment. Notably, DNA demethylation directly increased the expression of cytokines IL-11, IL-6, IL-α, and TNF-α under T-2 toxin exposure. DNA methylation inhibitors combined with T-2 toxin directly or indirectly induced the production of inflammatory cytokines and aggravate cell apoptosis. Our study uncovered for the first time that DNA methylation is related to the expression of inflammatory cytokines in T-2 toxin-induced liver injury. These findings suggested that DNA methylation is a potential mechanism of T-2 toxin-induced hepatotoxicity.

Biological Toxins as the Potential Tools for Bioterrorism

Biological toxins are a heterogeneous group produced by living organisms. One dictionary defines them as "Chemicals produced by living organisms that have toxic properties for another organism". Toxins are very attractive to terrorists for use in acts of bioterrorism. The first reason is that many biological toxins can be obtained very easily. Simple bacterial culturing systems and extraction equipment dedicated to plant toxins are cheap and easily available, and can even be constructed at home. Many toxins affect the nervous systems of mammals by interfering with the transmission of nerve impulses, which gives them their high potential in bioterrorist attacks. Others are responsible for blockage of main cellular metabolism, causing cellular death. Moreover, most toxins act very quickly and are lethal in low doses (LD50 < 25 mg/kg), which are very often lower than chemical warfare agents. For these reasons we decided to prepare this review paper which main aim is to present the high potential of biological toxins as factors of bioterrorism describing the general characteristics, mechanisms of action and treatment of most potent biological toxins. In this paper we focused on six most danger toxins: botulinum toxin, staphylococcal enterotoxins, Clostridium perfringens toxins, ricin, abrin and T-2 toxin. We hope that this paper will help in understanding the problem of availability and potential of biological toxins.

Mifepristone attenuates depression-like changes induced by chronic central administration of interleukin-1β in rats

Increased proinflammatory cytokines, such as interleukin (IL)-1β, may play an important role in the etiology of depression because they cause the hypothalamic-pituitary-adrenal axis to release glucocorticoids (GC) and induce dysfunction of serotonin and norepinephrine neurotransmission. Sustained increase in GC may activate microglia to induce neuroinflammation, and suppress astrocytes to produce neurotrophins, which lead to neuronal apoptosis. Here, we tested the hypothesis that glucocorticoid receptor (GR) antagonist mifepristone (RU486) may attenuate IL-1β-induced depression-like behavior by regulating the neuroinflammation and neurotrophin functions of microglia and astrocytes. Rats received intracerebroventricular injections of IL-1β (10 ng) and/or subcutaneous injections of RU486 for 14 days. Then animal depression-like behaviors, serum corticosterone concentration, the levels of pro-inflammatory cytokines (TNF-α, IL-6), mRNA and protein expressions of CD11b, GFAP and neurotrophins (pro-BDNF, BDNF, GDNF and their receptors TrkB, p75, GFRα-1 and GFRα-2) in the amygdala were studied. Compared to controls, significantly decreased rearing score and increased defecation in the open field test, decreases in ratio of open/closed time in the elevated plus maze and in sucrose preference, while increased level of corticosterone in the serum were found in the rats administrated with IL-1β. IL-1β administration also reduced the expressions of GFAP, BDNF, GDNF and its receptor GFR-α1, but increased the expressions of CD11b, pro-BDNF, p75 and pro-inflammatory cytokines (TNF-α, IL-6) concentrations. RU486 treatment markedly attenuated these changes induced by IL-1β, except for the expressions of GFR-α1. In conclusion, RU486 may improve depression-like changes by suppressing microglia and inflammation and promoting astrocytes to restore neurotrophin function.

T-2 mycotoxin treatment of newborn rat pups does not significantly affect nervous system functions in adulthood

T-2 toxin is primarily produced by Fusarium sp. abundant under temperate climatic conditions. Its main harmful effect is the inhibition of protein synthesis. Causing oxidative stress, it also promotes lipid peroxidation and changes plasma membrane phospholipid composition; this may lead to nervous system alterations. The aim of the present study was to examine whether a single dose of T-2 toxin administered at newborn age has any long-lasting effects on nervous system functions. Rat pups were treated on the first postnatal day with a single intraperitoneal dose of T-2 toxin (0.2 mg/bwkg). Body weight of treated pups was lower during the second and third week of life, compared to littermates; later, weight gain was recovered. At young adulthood, behavior was tested in the open field, and no difference was observed between treated and control rats. Field potential recordings from somatosensory cortex and hippocampus slices did not reveal any significant difference in neuronal network functions. In case of neocortical field EPSP, the shape was slightly different in treated pups. Long-term synaptic plasticity was also comparable in both groups. Seizure susceptibility of the slices was not different, either. In conclusion, T-2 toxin did not significantly affect basic nervous system functions at this dose.

T-2 toxin-induced toxicity in neuroblastoma-2a cells involves the generation of reactive oxygen, mitochondrial dysfunction and inhibition of Nrf2/HO-1 pathway

The molecular mechanisms of T-2 mycotoxin induced neurotoxicity remains enigmatic. In the present study we show that T-2 toxin induced neurotoxicity in mouse neuroblastoma2a (N2a) cells is both dose- and time-dependent and is associated with oxidative stress, mitochondrial dysfunction and apoptosis. T-2 toxin treatment of N2a cells at 10, 20, 40 and 80 ng/mL for 24 h significantly up-regulated the mRNA expression of p53, Bax, and caspase-8 and down-regulated the expression of Nrf2 and HO-1 mRNA and protein expression. Activation of caspases-8, -9 and -3 was also evident in a concentration-dependent manner. Pre-treatment of the cells with the antioxidant N-acetyl-cysteine markedly suppressed T-2 toxin-induced neurotoxicity and caspase activation. Conversely, pre-treatment of the cells with the Nrf2 inhibitor brusatol or the HO-1 inhibitor zinc protoporphyrin IX, enhanced T-2 toxin induced neurotoxicity and increased the activation of caspase-9 and -3. Taken together, these novel findings suggest that T-2 toxin-induced neurotoxicity in N2a cells involves oxidative stress, mitochondrial dysfunction and apoptosis via the inhibition of the Nrf2/HO-1 and activation of p53 pathway. The present study highlights the potential of developing much needed pharmacological interventions to prevent T-2 toxin neurotoxicity.

Potential implications of Apolipoprotein E in early brain injury after experimental subarachnoid hemorrhage: Involvement in the modulation of blood-brain barrier integrity

Apolipoprotein E (Apoe) genetic polymorphisms have been implicated in the long term outcome of subarachnoid haemorrhage (SAH), but little is known about the effect of Apoe on the early brain injury (EBI) after SAH. This study investigated the potential role of APOE in EBI post-SAH. Multiple techniques were used to determine the early BBB disruption in EBI post-SAH in a murine model using wild-type (WT) and Apoe^−/− (KO) mice. Progressive BBB disruption (Evans blue extravasation and T2 hyperintensity in magnetic resonance imaging) was observed before the peak of endogenous APOE expression elevation at 48h after SAH. Moreover, Apoe^−/− mice exhibited more severe BBB disruption charcteristics after SAH than WT mice, including higher levels of Evans blue and IgG extravasation, T2 hyperintensity in magnetic resonance imaging, tight junction proteins degradation and endothelial cells death. Mechanistically, we found that APOE restores the BBB integrity in the acute stage after SAH via the cyclophilin A (CypA)-NF-κB-proinflammatory cytokines-MMP-9 signalling pathway. Consequently, although early BBB disruption causes neurological dysfunctions after SAH, we capture a different aspect of the effects of APOE on EBI after SAH that previous studies had overlooked and open up the idea of BBB disruption as a target of APOE-based therapy for EBI amelioration research in the future.

Nitric oxide mediates apoptosis and mitochondrial dysfunction and plays a role in growth hormone deficiency by nivalenol in GH3 cells

Nivalenol (NIV), a type B trichothecenes commonly found in cereal crops, can cause growth impairment in animals. However, limited information about its mechanisms is available. Trichothecenes have been characterized as an inhibitor of protein synthesis and induce apoptosis in cells. Oxidative stress is considered an underlying mechanism. However, whether NIV can induce oxidative stress and apoptosis in rat pituitary cells line GH3 is unclear. The present study showed that NIV significantly reduced the viability of cells and caused oxidative stress in GH3 cells. Further experiments showed that nitric oxide (NO), but not ROS, mediated NIV-induced oxidative stress. Additionally, NIV induced caspase-dependent apoptosis, decrease in mitochondrial membrane potential and mitochondrial ultrastructural changes. However, NIV-induced caspase activation, mitochondrial damage and apoptosis were partially alleviated by Z-VAD-FMK or NO scavenger hemoglobin. Finally, NIV changed the expression of growth-associated genes and pro-inflammatory cytokines. NIV also reduced the GH secretion in GH3 cells, which was reversed by hemoglobin. Taken together, these results suggested that NIV induced apoptosis in caspase-dependent mitochondrial pathway in GH3 cells, which might be an underlying mechanism of NIV-induced GH deficiency. Importantly, NO played a critical role in the induction of oxidative stress, apoptosis and GH deficiency in NIV-treated GH3 cells.

Gas6 Promotes Oligodendrogenesis and Myelination in the Adult Central Nervous System and After Lysolecithin-Induced Demyelination

A key aim of therapy for multiple sclerosis (MS) is to promote the regeneration of oligodendrocytes and remyelination in the central nervous system (CNS). The present study provides evidence that the vitamin K-dependent protein growth arrest specific 6 (Gas6) promotes such repair in in vitro cultures of mouse optic nerve and cerebellum. We first determined expression of Gas6 and TAM (Tyro3, Axl, Mer) receptors in the mouse CNS, with all three TAM receptors increasing in expression through postnatal development, reaching maximal levels in the adult. Treatment of cultured mouse optic nerves with Gas6 resulted in significant increases in oligodendrocyte numbers as well as expression of myelin basic protein (MBP). Gas6 stimulation also resulted in activation of STAT3 in optic nerves as well as downregulation of multiple genes involved in MS development, including matrix metalloproteinase-9 (MMP9), which may decrease the integrity of the blood-brain barrier and is found upregulated in MS lesions. The cytoprotective effects of Gas6 were examined in in vitro mouse cerebellar slice cultures, where lysolecithin was used to induce demyelination. Cotreatment of cerebellar slices with Gas6 significantly attenuated demyelination as determined by MBP immunostaining, and Gas6 activated Tyro3 receptor through its phosphorylation. In conclusion, these results demonstrate that Gas6/TAM signaling stimulates the generation of oligodendrocytes and increased myelin production via Tyro3 receptor in the adult CNS, including repair after demyelinating injury. Furthermore, the effects of Gas6 on STAT3 signaling and matrix MMP9 downregulation indicate potential glial cell repair and immunoregulatory roles for Gas6, indicating that Gas6-TAM signaling could be a potential therapeutic target in MS and other neuropathologies.

Glial Cell-Elicited Activation of Brain Microvasculature in Response to Brucella abortus Infection Requires ASC Inflammasome-Dependent IL-1β Production

Blood-brain barrier activation and/or dysfunction are a common feature of human neurobrucellosis, but the underlying pathogenic mechanisms are largely unknown. In this article, we describe an immune mechanism for inflammatory activation of human brain microvascular endothelial cells (HBMEC) in response to infection with Brucella abortus Infection of HBMEC with B. abortus induced the secretion of IL-6, IL-8, and MCP-1, and the upregulation of CD54 (ICAM-1), consistent with a state of activation. Culture supernatants (CS) from glial cells (astrocytes and microglia) infected with B. abortus also induced activation of HBMEC, but to a greater extent. Although B. abortus-infected glial cells secreted IL-1β and TNF-α, activation of HBMEC was dependent on IL-1β because CS from B. abortus-infected astrocytes and microglia deficient in caspase-1 and apoptosis-associated speck-like protein containing a CARD failed to induce HBMEC activation. Consistently, treatment of CS with neutralizing anti-IL-1β inhibited HBMEC activation. Both absent in melanoma 2 and Nod-like receptor containing a pyrin domain 3 are partially required for caspase-1 activation and IL-1β secretion, suggesting that multiple apoptosis-associated speck-like protein containing CARD-dependent inflammasomes contribute to IL-1β-induced activation of the brain microvasculature. Inflammasome-mediated IL-1β secretion in glial cells depends on TLR2 and MyD88 adapter-like/TIRAP. Finally, neutrophil and monocyte migration across HBMEC monolayers was increased by CS from Brucella-infected glial cells in an IL-1β-dependent fashion, and the infiltration of neutrophils into the brain parenchyma upon intracranial injection of B. abortus was diminished in the absence of Nod-like receptor containing a pyrin domain 3 and absent in melanoma 2. Our results indicate that innate immunity of the CNS set in motion by B. abortus contributes to the activation of the blood-brain barrier in neurobrucellosis and IL-1β mediates this phenomenon.

Delay of the onset of puberty in female rats by prepubertal exposure to T-2 toxin

Growing evidence has revealed the deleterious influence of environmental and food contaminants on puberty onset and development in both animals and children, provoking an increasing health concern. T-2 toxin, a naturally-produced Type A trichothecene mycotoxin which is frequently found in cereal grains and products intended for human and animal consumption, has been shown to impair the reproduction and development in animals. Nevertheless, whether this trichothecene mycotoxin can disturb the onset of puberty in females remains unclear. To clarify this point, infantile female rats were given a daily intragastric administration of vehicle or 187.5 μg/kg body weight of T-2 toxin for five consecutive days from postnatal day 15 to 19, and the effects on puberty onset were evaluated in the present study. The results revealed that the days of vaginal opening, first dioestrus, and first estrus in regular estrous cycle were delayed following prepubertal exposure to T-2 toxin. The relative weights of reproductive organs uterus, ovaries, and vagina, and the incidence of corpora lutea were all diminished in T-2 toxin-treated rats. Serum levels of gonadotropins luteinizing hormone, follicle-stimulating hormone, and estradiol were also reduced by T-2 toxin treatment. The mRNA expressions of hypothalamic gonadotropin-releasing hormone (GnRH) and pituitary GnRH receptor displayed significant reductions following exposure to T-2 toxin, which were consistent with the changes of serum gonadotropins, delayed reproductive organ development, and delayed vaginal opening. In conclusion, the present study reveals that prepubertal exposure to T-2 toxin delays the onset of puberty in immature female rats, probably by the mechanism of disturbance of hypothalamic-pituitary-gonadal (HPG) axis function. Considering the vulnerability of developmental children to food contaminants and the relative high level of dietary intake of T-2 toxin in children, we think the findings of the present study provide valuable information for the health risk assessment in children.

The Putative Role of Viruses, Bacteria, and Chronic Fungal Biotoxin Exposure in the Genesis of Intractable Fatigue Accompanied by Cognitive and Physical Disability

Patients who present with severe intractable apparently idiopathic fatigue accompanied by profound physical and or cognitive disability present a significant therapeutic challenge. The effect of psychological counseling is limited, with significant but very slight improvements in psychometric measures of fatigue and disability but no improvement on scientific measures of physical impairment compared to controls. Similarly, exercise regimes either produce significant, but practically unimportant, benefit or provoke symptom exacerbation. Many such patients are afforded the exclusionary, non-specific diagnosis of chronic fatigue syndrome if rudimentary testing fails to discover the cause of their symptoms. More sophisticated investigations often reveal the presence of a range of pathogens capable of establishing life-long infections with sophisticated immune evasion strategies, including Parvoviruses, HHV6, variants of Epstein-Barr, Cytomegalovirus, Mycoplasma, and Borrelia burgdorferi. Other patients have a history of chronic fungal or other biotoxin exposure. Herein, we explain the epigenetic factors that may render such individuals susceptible to the chronic pathology induced by such agents, how such agents induce pathology, and, indeed, how such pathology can persist and even amplify even when infections have cleared or when biotoxin exposure has ceased. The presence of active, reactivated, or even latent Herpes virus could be a potential source of intractable fatigue accompanied by profound physical and or cognitive disability in some patients, and the same may be true of persistent Parvovirus B12 and mycoplasma infection. A history of chronic mold exposure is a feasible explanation for such symptoms, as is the presence of B. burgdorferi. The complex tropism, life cycles, genetic variability, and low titer of many of these pathogens makes their detection in blood a challenge. Examination of lymphoid tissue or CSF in such circumstances may be warranted.

Zearalenone mycotoxin affects immune mediators, MAPK signalling molecules, nuclear receptors and genome-wide gene expression in pig spleen

The toxicity of zearalenone (ZEA) was evaluated in swine spleen, a key organ for the innate and adaptative immune response. Weaned pigs were fed for 18 days with a control or a ZEA contaminated diet. The effect of ZEA was assessed on wide genome expression, pro- (TNF-α, IL-8, IL-6, IL-1β, IFN-γ) and anti-inflammatory (IL-10, IL-4) cytokines, other molecules involved in inflammatory processes (MMPs/TIMPs), as well as signaling molecules, (p38/JNK1/JNK2-MAPKs) and nuclear receptors (PPARγ/NFkB/AP-1/STAT3/c-JUN). Microarray analysis showed that 46% of total number of differentially expressed genes was involved in cellular signaling pathway, 13% in cytokine network and 10% in the inflammatory response. ZEA increased expression and synthesis of pro- inflammatory (TNF-α, IL-8, IL-6, IL-1β) and had no effect on IFN-γ, IL-4 and IL-10 cytokines in spleen. The inflammatory stimulation might be a consequence of JNK pathway activation rather than of p-38MAPK and NF-kB involvement whose gene and protein expression were suppressed by ZEA action. In summary, our findings indicated the role of ZEA as an immune disruptor at spleen level.

Dysregulation of energy balance by trichothecene mycotoxins: Mechanisms and prospects

Trichothecenes are toxic metabolites produced by fungi that constitute a worldwide hazard for agricultural production and both animal and human health. More than 40 countries have introduced regulations or guidelines for food and feed contamination levels of the most prevalent trichothecene, deoxynivalenol (DON), on the basis of its ability to cause growth suppression. With the development of analytical tools, evaluation of food contamination and exposure revealed that a significant proportion of the human population is chronically exposed to DON doses exceeding the provisional maximum tolerable daily dose. Accordingly, a better understanding of trichothecene impact on health is needed. Upon exposure to low or moderate doses, DON and other trichothecenes induce anorexia, vomiting and reduced weight gain. Several recent studies have addressed the mechanisms by which trichothecenes induce these symptoms and revealed a multifaceted action targeting gut, liver and brain and causing dysregulation in neuroendocrine signaling, immune responses, growth hormone axis, and central neurocircuitries involved in energy homeostasis. Newly identified trichothecene toxicosis biomarkers are just beginning to be exploited and already open up new questions on the potential harmful effects of chronic exposure to DON at apparently asymptomatic very low levels. This review summarizes our current understanding of the effects of DON and other trichothecenes on food intake and weight growth.

Differential effects of route of T-2 toxin exposure on hepatic oxidative damage in mice

T-2 toxin is the most toxic among mycotoxins and poses a potential health hazard for both humans and animals. At high doses, T-2 toxin can cause shock-like syndrome that can result in death. We evaluated the effect of time course and route of exposure on hepatic oxidative damage in mice and it is only such study so far to compare the effects of dermal and subcutaneous exposure of T-2 toxin. Mice were exposed to 1 LD50 of T-2 toxin either by percutaneous (5.94 mg/kg body weight) or subcutaneous (1.54 mg/kg body weight) route and sacrificed at 0, 1, 3, and 7 days postexposure. Analysis of a number of serum biochemical variables, antioxidant enzymes activity, gene and protein expression by immunoblot assay showed time and route dependent effects of T-2 induced hepatic oxidative damage. Time dependent increase in protein carbonyl content and protein oxidation was seen in serum and liver. Results of our study may provide possible mechanism for developing medical countermeasures against T-2 toxin.