TDK conference 2020

Potential mycotoxin contamination of cereals and cereal-based foods poses a significant risk. The trichothecenes deoxynivalenol (DON) and T-2 toxin, produced by Fusarium species, are common mycotoxins worldwide. Dietary mycotoxins can cause diseases of various appearance and duration in both animals and humans, thus posing a serious risk to our health in addition to significant economic damage. DON and T-2 toxin can also co-occur in infected plants, so mapping the effect of their combination in intestinal epithelial cell models is of practical importance.

In our study, we examined DON and T-2 toxin alone and in combination, using human, non-cancerous intestinal epithelial cell line HIEC-6. Cell viability was measured by MTS assay, extracellular hydrogen peroxide (H2O2) levels by Amplex Red assay, intracellular redox status by DCFH-DA assay, IL-6 and IL-8 inflammatory cytokines by sandwich ELISA, and claudin-1 and occludin localization was determined by confocal microscopy using immunofluorescence staining.

According to our 24-hour experimental results, significant cell death was observed for DON at 5 µmol/L, for T-2 toxin at 10 nmol/L and for DT2 combination treatment at 5 µmol/L DON + 10 nmol/L T-2. Twenty-four hours after treatment, 1 µmol/L DON, 5 nmol/L T-2 and 1 µmol/L DON + 5 nmol/L T-2 combination DT2 treatment significantly increased extracellular H2O2 production and intracellular oxidative stress compared to control values. Each of the treatments significantly increased IL-6 and IL-8 levels compared to basal IL-6 and IL-8 production by cells that did not receive mycotoxin treatment. Mycotoxin exposure decreased the expression of claudin-1 protein, while the expression of occludin remained unchanged.

Our study examined firstly the effects of mycotoxins DON and T-2, administered separately or in combination for 24 hrs on the viability of HIEC-6 cells. We verified that the HIEC-6 cell line is a suitable in vitro experimental model for demonstrating the pro-inflammatory and pro-oxidant characteristics of foodborne mycotoxins. Based on our experimental evidence, it can be concluded that mycotoxins administered below cytotoxic concentrations raise both extra- and intracellular oxidative stress and the production of inflammatory cytokines IL-6 and IL-8. DON and T-2 applied separately, as well as in combination, significantly decreased the expression of TJ protein claudin-1, while the expression of occludin remained unchanged.