Phosphatidylcholine-specific phospholipase C and phospholipase D are activated by oxidative injury

MATEOS, MELINA; URANGA, ROMINA; SALVADOR, GABRIELA; GIUSTO, NORMA

Mar del Plata, Buenos Aires, Argentina.

Congreso; XLIII Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2007

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB)

Our purpose was to characterize the state of phospholipase D (PLD) and phosphatidylcholine-specific phospholipase C (PC-PLC) pathways in cerebral cortex synaptosomes (Syn) from adult and aged rats exposed to oxidative stress. Oxidative injury induced by FeSO4 increased diacylglycerol (DAG) generation by 77% with respect to control conditions both in adult and aged animals. Experiments carried out in the presence of ethanol, demonstrated that both PLD and PC-PLC pathways contributed to DAG generation in the presence of iron. For determining the cellular fate of DAG produced from PC, assays were performed in the presence of either RHC80267 (DAG lipase inhibitor) or R59022 (DAG kinase inhibitor) or U73122 (PIP2-PLC inhibitor). Under control conditions, these inhibitors did not modify DAG levels generated from PC. Similar results were observed in the presence of free iron. U73122 decreased DAG levels by 23% after 60 min of iron exposure in adult animals. This effect was not observed in senile animals. Preincubation of Syn with Genistein or Herbimycin A, two tyrosine kinases inhibitors, did not modify the DAG increase induced by Fe2+. The presence of sodium vanadate (tyrosine phosphatase inhibitor) strongly inhibited DAG generation under control and stimulation conditions. Our results show that oxidative stress activates DAG generation pathways in synaptic endings from adult and aged rats.