Hydrogen peroxide induces the activation of the phospholipase C-gamma1 survival pathway in PC12 cells: protective role in apoptosis.
It has been reported that phospholipase C-gamma1 (PLC-gamma1) plays an important protective role in hydrogen peroxide (H(2)O(2))-induced pheochromocytoma (PC) 12 cells death. However, most studies have used high doses of H2O2 and the downstream targets of PLC-gamma1 activation remain to be identified. The present study was designed to examine the roles of PLC-gamma1 signaling pathway in the apoptosis of PC12 cells induced by low dose of H(2)O(2), as well as the downstream factors involved in this pathway. Low-dose treatment of H(2)O(2) resulted in PLC-gamma1 tyrosine phosphorylation in a time-dependent manner and H(2)O(2) killed the PC12 cells by inducing necrosis. In contrast, pretreatment of PC12 cells with U73122, a specific inhibitor of PLC, markedly increased the percentage of dead cells. The mode of cell death was converted to apoptosis as determined by Hoechst/PI nuclear staining and fluorescence microscopy. Western blot analysis demonstrated that the expression of Bcl-2 protein and the activation of pro-caspase-3 were not significantly affected by low dose of H(2)O(2) alone. However, after pretreatment with U73122, Bcl-2 protein expression was dramatically decreased and the activation of pro-caspase-3 was significantly increased. We concluded that PLC-gamma1 plays an important protective role in H(2)O(2)-induced PC12 cells death. Bcl-2 and caspase-3 probably participate in the signaling pathway as downstream factors.
Yuan
Wenli
W
Department of Anatomy, Kunming Medical University, Kunming, China.
Guo
Jiazhi
J
Li
Xingguo
X
Zou
Zhirong
Z
Chen
Guangxue
G
Sun
Jun
J
Wang
Tinghua
T
Lu
Di
D
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects*; D004789:Enzyme Activation / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D016877:Oxidants / Q000494:pharmacology; D016716:PC12 Cells; D051966:Phospholipase C gamma / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects*
D016877:Oxidants; D019253:Proto-Oncogene Proteins c-bcl-2; D006861:Hydrogen Peroxide; D051966:Phospholipase C gamma; D053148:Caspase 3