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[GRP75 overexpression inhibits apoptosis induced by glucose deprivation via Raf/Mek/Erk1/2 signaling pathway.] [Article in Chinese]

LI Hong-Yan, YANG Ling^*, LIU Wen, ZUO Ji

Department of Cellular and Genetic Medicine, Shanghai Medical College, Fudan University, Shanghai 200032, China

Abstract

The purpose of the present study is to investigate whether glucose-regulated protein 75 (GRP75) overexpression inhibits apoptosis induced by glucose deprivation through Raf/Mek/Erk1/2 signaling pathway. After pretreatment with Mek-specific inhibitor U0126, GRP75 overexpressing PC12 cells were incubated in glucose-free DMEM medium for indicated time (6, 12 and 24 h). And DMSO-treated GRP75 overexpressing PC12 cells were applied as control. Western blot was used to determine the expression and phosphorylation level of Erk1/2. MTT assay was used to measure cell viability. Hoechst 33258 staining and flow cytometry using propidium iodide (PI) staining was used to analysis apoptosis. Immunofluorescence with antibody against cytochrome c (Cyt c) was used to detect Cyt c release from mitochondrion. The results showed U0126 prevented the activation of Erk1/2 maintained by GRP75, but the total Erk1/2 expression was not affected. U0126-treated group showed lower cell viability and higher apoptotic rate compared with control group. Immunofluorescence indicated the delay in release of Cyt c was blocked by U0126. These results suggest U0126 prevents protective effect of GRP75 on PC12 cells by inhibiting Erk1/2 phosphorylation, which certifies that GRP75 can inhibit the mitochondria-dependent apoptotic pathway through Raf/Mek/Erk1/2 signaling cascade.

Key words: glucose-regulated protein 75; Raf/Mek/Erk1/2; apoptosis

Received: 2010-11-08　　Accepted: 2010-12-14

Corresponding author: 杨玲　　E-mail: yangling@fudan.edu.cn

Citing This Article：

LI Hong-Yan, YANG Ling, LIU Wen, ZUO Ji. [GRP75 overexpression inhibits apoptosis induced by glucose deprivation via Raf/Mek/Erk1/2 signaling pathway.] [Article in Chinese]. Acta Physiol Sin 2011; 63 (1): 69-74 (in Chinese with English abstract).