Short communicationMicrocystins activate nuclear factor erythroid 2-related factor 2 (Nrf2) in human liver cells in vitro - Implications for an oxidative stress induction by microcystins

•Four microcystins were studied to investigate if they induce oxidative stress.•All four compounds significantly increased the Nrf2 activity.•These results suggest that microcystins may induce oxidative stress response.

Microcystins, a potential threat to drinking water quality, are hepatotoxic but it has remained unclear if microcystins induce oxidative stress. We investigated if four microcystins could activate the Nrf2 pathway, a regulator of oxidative stress response. Nrf2 activity was significantly increased by microcystin-LR and -RR at 10 μM, by microcystin-LY at 3 μM, by [D-Asp3]-LR and by microcystin-LR at 1 μM. Our results lend support to the suggestion that microcystins may induce oxidative stress response.