Effect of protein glutathionylation on neuronal cytoskeleton: a potential link to neurodegeneration

Neurons are highly susceptible to oxidative stress and oxidation of cytoskeletal proteins is considered one of the first steps of neurodegeneration. Protein glutathionylation is a key event in the redox regulation of protein function and constitutes a sensor of tissue oxidative stress in patho-physiological conditions. In this study, we analyzed for the first time tubulin glutathionylation and its relation to neurites degeneration. For this purpose, we exposed motoneuronal cells to the physiological oxidant glutathione disulfide (GSSG) and we analyzed the extent and morphology of axonal changes caused by protein glutathionylation in these cells. Then we studied the effect of glutathionylation on the distribution of stable and dynamic microtubules in the same cells. Our results indicate that oxidative stress conditions determined by an increased intracellular level of oxidized glutathione may cause an alteration of the cytoskeleton organization and function leading to axon degeneration. These findings might contribute to understand the sequence of pathogenic events involved in the axonal degeneration that characterizes many diseases of the nervous system associated with oxidative stress.