Role of phospholipase D on glutamate-induced cell death in PC12 cells

Abstract

In attempt to explore the mechanism of glutamate-induced cell death in rat pheochromocytoma (PC12) cells, we observed the effect of glutamate exposure on PLD activity and ceramide generation in PC12 cells. The cell viability was gradually decreased with the increment of glutamate concentration (10mM~10mM) in a dose-dependent manner. The treatment of PC12 cells by 10mM glutamate induced a cell death in a time-dependent manner. Glutamate decreased the PLD activity in a concentration- or time-dependent manner, reaching a minimal level at 1 hour. Ceramide level was increased by 10mM glutamate in a time-dependent manner, reaching a maximal level at 6 hours. On the other hand, PC12 cells underwent significant sphingomyelin hydrolysis in response to glutamate. Incubation of PC12 cells with exogenous 25mM C6-ceramide showed a time-dependent decrease of PLD activity. When cDNAs of PLD1 and PLD2 were transfected into PC12 cells, glutamate-induced cell death was suppressed clearly. These results indicate that the glutamate/ceramide signaling pathway might play a role in PC12 cells cell death and suggest that the PLD pathway might be cross-linked to the glutamate/ceramide pathway, showing a protective role against glutamate-induced cell death in PC12 cells.