P12-08 Oxidative and inflammatory pathways after T-2 toxin exposure in HepG2 cells

Mycotoxins are secondary metabolites produced by filamentous fungi, that are often present in food. Fusarium species produce the T-2 toxin (T-2), which is mainly found in oats. This is the most toxic mycotoxin of the trichothecenes group. The main toxic effects of T-2 are hepatotoxicity, nephrotoxicity, neurotoxicity and gastrointestinal disorders. Although the maximum tolerable levels of T-2 in cereals have been established, they need to be re-evaluated because of their toxicity. Therefore, it is necessary to carry out toxicity studies to understand its mechanisms of toxicity completely. So, in this study, the metabolic pathway associated with inflammatory and oxidative processes was evaluated, as this area has been little studied. The hepatocarcinoma (HepG2) cells were exposed to 7.5, 15 and 30 nM T-2 for 24 h to quantify the gene expression of the interleukins TNF-α, IL-1β and IL-6 and the proteins Nrf2 and HO-1. This was carried out by qPCR and the results were confirmed by western blotting. The results demonstrated alterations in HepG2 cell morphology in a concentration-dependent manner by indirect immunofluorescence analysis. Respect to inflammatory and oxidative factors, we observed that, the IL-1β mRNA, IL-6 and TNF- α mRNA were up-regulated at the highest concentration tested compared to the control. And, the Nrf2 mRNA was down-regulated by T-2 at all concentrations tested. Western blot results showed the bands referred to IL-6, which intensity was increased up to 1.95 folds at 30 nM of T-2, compared to the negative control. Regarding the bands of oxidative proteins, Nrf2 were detected with a decrease at the highest concentration (0.67 folds compared to the control) and a decrease of 2.31 folds of HO-1 compared to the control was detected at the lowest concentration of T-2. In summary, the overexpression of inflammatory pathway genes and downregulation of genes related to oxidative processes suggest that T-2 exposure produces toxicity through activation of the inflammatory pathway, and inhibition of the Nrf2/HO-1 pathway in HepG2 cells. Acknowledgments: Spanish Ministry of Science and Innovation(PID2020-115871RB-I00) and the State of Investigation Agency MCIN/AEI/10.13039/501100011033. Mercedes Taroncher is grateful for the postdoctoral grant PRE2021-096941 provided by the Spanish Ministry of Science and Innovation project.