Nutrition- and virus-induced stress represses the expression of manganese superoxide dismutase in vitro.
Résumé
The relationship between oxidative stress and neuronal cell death has been suggested for many years. To understand the influence of oxidative stress on neuronal cell death, we investigated the influence of oxidative stress on DEV cells, a human glial cell line. Using enterovirus infection and/or malnutrition to induce oxidative stress, our results demonstrate that those stressors severely influence the antioxidant defense system in DEV cells. Although the expression of mitochondrial manganese superoxide dismutase (MnSOD) in DEV cells was significantly increased in acute infection with viral and nutritional stress, in persistent infection and nutritional stress, the expression of the MnSOD was drastically downregulated. We believe that this downregulation of MnSOD expression in the chronic stress model is due to repression of antioxidant defense. The downregulation of the MnSOD expression may lead to an increase of free-radical production and thus explain why the cells in the chronic stress model were more vulnerable to other oxidative stress influences. The vulnerability of DEV cells to additional stress factors resulted in progressive cell death, which may be analogous to the cell death in neurodegenerative diseases.