Thymocyte apoptosis by T-2 toxin in vivo in mice is independent of Fas/Fas ligand system

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.

T-2 toxin, a trichothecene mycotoxin: review of toxicity, metabolism, and analytical methods

This review focuses on the toxicity and metabolism of T-2 toxin and analytical methods used for the determination of T-2 toxin. Among the naturally occurring trichothecenes in food and feed, T-2 toxin is a cytotoxic fungal secondary metabolite produced by various species of Fusarium. Following ingestion, T-2 toxin causes acute and chronic toxicity and induces apoptosis in the immune system and fetal tissues. T-2 toxin is usually metabolized and eliminated after ingestion, yielding more than 20 metabolites. Consequently, there is a possibility of human consumption of animal products contaminated with T-2 toxin and its metabolites. Several methods for the determination of T-2 toxin based on traditional chromatographic, immunoassay, or mass spectroscopy techniques are described. This review will contribute to a better understanding of T-2 toxin exposure in animals and humans and T-2 toxin metabolism, toxicity, and analytical methods, which may be useful in risk assessment and control of T-2 toxin exposure.

T-2 toxin-induced toxicity in pregnant mice and rats

T-2 toxin is a cytotoxic secondary fungal metabolite that belongs to the trichothecene mycotoxin family. This mycotoxin is a well known inhibitor of protein synthesis through its high binding affinity to peptidyl transferase, which is an integral part of the ribosomal 60s subunit, and it also inhibits the synthesis of DNA and RNA, probably secondary to the inhibition of protein synthesis. In addition, T-2 toxin is said to induce apoptosis in many types of cells bearing high proliferating activity. T-2 toxin readily passes the placenta and is distributed to embryo/fetal tissues, which include many component cells bearing high proliferating activity. This paper reviews the reported data related to T-2 toxin-induced maternal and fetal toxicities in pregnant mice and rats. The mechanisms of T-2 toxin-induced apoptosis in maternal and fetal tissues are also discussed in this paper.

T-2 Toxin: Incidence and Toxicity in Poultry

T-2 toxin is the most toxic type A trichothecene mycotoxin. It is the secondary metabolite of the Fusarium fungi, and is common in grain and animal feed. Toxic effects have been shown both in experimental animals and in livestock. It has been implicated in several outbreaks of human mycotoxicoses. Toxic effects in poultry include inhibition of protein, DNA, and RNA synthesis, cytotoxicity, immunomodulation, cell lesions in the digestive tract, organs and skin, neural disturbances and low performance in poultry production (decreased weight gain, egg production, and hatchability). Concentrations of T-2 toxin in feed are usually low, and its immunosuppressive effects and secondary infections often make diagnosis difficult. If at the onset of the disease, a change in diet leads to health and performance improvements in animals, this may point to mycotoxin poisoning. Regular control of grain and feed samples is a valuable preventive measure, and it is accurate only if representative samples are tested. This article reviews the incidence and toxic effects of T-2 toxin in poultry.

Morphological and microarray analysis of T-2 toxin-induced rat fetal brain lesion

To examine morphological and gene expression changes induced by T-2 toxin in the fetal brain in detail, pregnant rats on day 13 of gestation were treated orally with a single dose of T-2 toxin (2 mg/kg) and sacrificed at 1, 3, 6, 9, 12 and 24 h after treatment (HAT). Histopathologically, the number of apoptotic neuroepithelial cells in the telencephalon increased from 1 HAT and peaked at 12 HAT. Based on the histopathological examinations, microarray analysis was performed at 6, 12 and 24 HAT. Microarray analysis showed that the expression of oxidative stress-related genes (heat shock protein 70 (HSP70) and heme oxygenase (HO)) was strongly induced by T-2 toxin at 12 HAT, the peak time point of apoptosis induction. The expression of mitogen-activated protein kinase (MAPK)-related genes (MEKK1 and c-jun) and other apoptosis-related genes (caspase-2 and insulin-like growth factor-binding protein-3 (IGF-BP3)) was also induced by the T-2 toxin treatment. The changes observed by microarray analysis were confirmed for four up-regulated genes (HSP70, HO, IGF-BP3 and VEGF-A) using real-time RT-PCR. Our results suggest that the T-2 toxin-induced apoptosis in the fetal brain is due to oxidative stress, and that the MAPK pathway may be involved in T-2 toxin-induced toxicity.

1,4-benzothiazine analogues and apoptosis: structure-activity relationship

We have previously shown 1,4-benzothiazine (1,4-B) derivatives induce thymocyte apoptosis in vitro and thymus cell loss in vivo. Apoptosis is mediated through a complex of biochemical events including phosphatidylcholine specific-phospholipase C (PC-PLC) activation, acidic sphingomyelinase (aSMase) activation and ceramide generation, caspase-8 and caspase-3 activation. As preliminary analysis of the structure-activity relationship (SAR) suggested some structural features were responsible for apoptosis, we synthesised several derivatives and tested for apoptosis activity at equimolar concentrations. In particular, we synthesised analogues that differed in the nature of skeleton (1,4-benzothiazine, 1,4-benzoxazine and 1,2,3,4-tetrahydroquinoline) and in the nature of side chain (imidazole, benzimidazole or piperazine as azole substituent; presence, absence or transformation of alcoholic group). Results of apoptosis induction indicate that transforming the 1,4-benzothiazine skeleton into 1,2,3,4-tetrahydroquinoline does not result in significant change. Transformation into 1,4-benzoxazine decreased activity. Replacing imidazole at the side chain with different piperazines also decreased activity while replacing it with benzimidazole does not change apoptotic activity. Finally, removal of the alcoholic group by dehydration to olefin, or by transforming it into ether, increased activity. Moreover, in an attempt to analyse further the SAR characteristics that are responsible for 1,4-B-activated apoptosis we tested the effect on caspase-8,-9 and-3 activation. 1,4-B analogues activate caspases and the structural requirements correlate with those responsible for apoptosis induction.

Induction of apoptosis by 1,4-benzothiazine analogs in mouse thymocytes

1,4-benzothiazine (1,4-B) derivatives exert numerous effects in vivo and in vitro, including neurotoxicity and antitumor cytotoxicity. To analyze the mechanisms responsible for 1,4-B-induced cytotoxicity, we performed experiments to evaluate the possible apoptotic effect. For that purpose, we used mouse thymocytes, a cell population well sensitive to induction of apoptosis that has been used to assay apoptosis in many experimental systems. Results indicate that a number of 1,4-B analogs are able to induce both thymocyte apoptosis in vitro and thymus cell loss in vivo. Moreover, analysis of the structure-activity relationship indicate that the sulfur (S) oxidation state, the presence of the carbonyl group, and the nature and position of the side chain modulate the apoptotic efficacy. Moreover, results of in vitro experiments show that the 1,4-B-induced apoptosis associates with different biochemical events including phosphatidylcholine-specific phospholipase C activation, acidic sphingomyelinase activation and ceramide generation, loss of mitochondrial membrane potential (DeltaPsi(m)) and cytochrome c release, and caspase-8, -9, and -3 activation. These results indicate that 1,4-B analogs induce apoptosis through a complex of biochemical events.