ANTIOXIDANT SYSTEMS IN BRAIN ASTROCYTES: SOURCES OF CYSTEINE FOR GLUTATHIONE

Astrocytes supply neurons with the antioxidant, glutathione. Cysteine is the precursor of glutathione and is imported as cystine via the plasma-membrane cystine glutamate exchanger. Recent evidence has shown that the transsulphuration pathway that converts methionine to cysteine also contributes to glutathione in astrocytes. Data on the relationship between the cystine glutamate exchanger and the transsulphuration pathway and changes in response to oxidative stress in astrocytes will be presented. The implications of this work for targeting pathways of cysteine metabolism in neurodegenerative disease will be discussed.