“Phospholipase D and phosphatidylinositol 3-kinase are activated by oxidative stress in central nervous system”

SALVADOR, GABRIELA ALEJANDRA; URANGA, ROMINA MARÍA; MATEOS, MELINA VALERIA; GIUSTO, NORMA MARÍA

San Diego, California, USA

Congreso; American Society for Biochemistry and Molecular Biology (ASBMB) Annual Meeting; 2008

The purpose of the present work was to study the involvement of phospholipase D (PLD) and phosphoinositide-3-kinase (PI3K) signaling in synaptic endings incubated under oxidative stress injury.  For this purpose, synaptosomes purified from rat cerebral cortex were exposed to the oxidative insult (FeSO4, 50 mM) or vehicle and subsequently phosphatidylethanol (Peth) and phosphatinolsitol-3-phosphate generation were evaluated. Peth formation was increased after 5, 30, and 60 min of Fe2+-exposure with respect to the controls, whereas PI3P levels were only increased after 5 min of Fe2+ exposure. PI3K activity was also measured by using anti-p85 immunoprecipitates. Peth generation was not altered by the presence of the tyrosine kinase inhibitor, genistein, whereas PI3K activation was dependent on tyrosine phosphorylation. Synaptosomal viability was evaluated by using MTT reduction and LDH leakage measurements under all experimental conditions. These viability parameters were significantly affected in the presence of FeSO4, with respect to control conditions. Neither ethanol nor LY294002 were able to prevent the deleterious effect of free iron. Our results demonstrate that oxidative stress activates PLD and PI3K pathways in cerebral cortex synaptic endings.