Identification and Apoptotic Potential of T-2 Toxin Metabolites in Human Cells

Abstract

The mycotoxin T-2 toxin, produced by various Fusarium species, is a widespread contaminant of grain and grain products. Knowledge about its toxicity and metabolism in the human body is crucial for any risk assessment as T-2 toxin can be detected in processed and unprocessed food samples. Cell culture studies using cells of human origin represent a potent model system to study the metabolic fate of T-2 toxin as well as the cytotoxicity in vitro. In this study the metabolism of T-2 toxin was analyzed in a cell line derived from human colon carcinoma cells (HT-29) and primary human renal proximal tubule epithelial cells (RPTEC) using high-performance liquid chromatography coupled with Fourier transformation mass spectrometry (HPLC-FTMS). Both cell types metabolized T-2 toxin to a variety of compounds. Furthermore, cell cycle analysis in RPTEC proved the apoptotic effect of T-2 toxin and its metabolites HT-2 toxin and neosolaniol in micromolar concentrations.

Influence of T-2 and HT-2 Toxin on the Blood-Brain Barrier In Vitro: New Experimental Hints for Neurotoxic Effects

“…No HT-2 toxin was detectable after incubations with T-2 toxin, while this conversion is well described in literature for various cell types in vitro : primary cells of different human origin like RPTEC (kidney), NHA (astrocytes), NHLF (lung fibroblasts) as well as cell lines derived from human colon carcinoma cells (HT-29) metabolize T-2 toxin rapidly to HT-2 toxin [10], [11]. Metabolism studies mimicking the human gastrointestinal tract found also HT-2 toxin as the main or even sole metabolite after T-2 toxin application [25].…”

“…Concerning the toxicity, T-2 and HT-2 toxin exhibit similar toxic properties: caspase-3-activation and subG1 formation as indicators of apoptosis were observed in primary human kidney cells for both toxins in similar concentration ranges [10], 11. Moreover, T-2 toxin is a well described inhibitor of eukaryotic protein synthesis.…”

“…Both toxins were chosen since most studies concerning effects on the CNS dealt only with T-2 toxin neglecting its main metabolite HT-2 toxin which was already shown to exhibit similar cytotoxic effects as the parent toxin on various cell types [10]. HT-2 toxin was also formed following T-2 toxin application after short incubation periods in in vitro studies in primary human kidney cells [10], [11] as well as in a model reflecting the metabolism in the human gastrointestinal tract [25] indicating its potential presence in vivo after T-2 toxin ingestion. In this study, the BBB was mimicked by porcine brain capillary endothelial cells (PBCEC) seeded on polycarbonate Transwell® filter inserts [26].…”

Appropriateness to set a group health based guidance value for T2 and HT2 toxin and its modified forms

“…Several older in vivo and in vitro studies in animals provide indirect evidence for the formation of glucuronides of T2, HT2, 3-hydroxy-T2 and 3-hydroxy-HT2 by demonstrating the release of the respective aglycones from a polar metabolite fraction, assumed to represent glucuronides, upon treatment with the enzyme b-glucuronidase (reviewed by Weidner et al, 2012). More recently, LC-MS together with reference compounds has been used to identify T2-GlcA and HT2-3-GlcA in two human cell types after incubation with T2 (Weidner et al, 2012). When hepatic microsomes of rat, mouse, pig and human were incubated with T2 in the presence of uridine 5 0 -diphospho-glucuronic acid (UDPGA) and the pattern of glucuronides determined by LC-MS/MS, human microsomes exhibited a higher activity for glucuronidation than rodent or pig microsomes.…”

“…A mixture of HT2-3-GlcA and HT2-4-GlcA was also demonstrated in the urine of female pigs dosed orally or by intravenous (i.v.) injection with T2 (Weidner et al, 2012).…”