Previous studies demonstrated that exendin-4 (Ex-4) may possess neurotrophic and neuroprotective functions in ischemia insults, but its mechanism remained unknown. Here, by using real-time PCR and ELISA, we identified the distribution of active GLP-1Rs in the rat primary cortical neurons. After establishment of an in vitro ischemia model by oxygen/glucose deprivation (OGD), neurons were treated with various dosages of Ex-4. The MTT assay showed that the relative survival rate increased with the dosage of Ex-4 ranging from 0.2 to 0.8 mu g/ml (P < 0.001, vs. OGD group). The apoptosis rate was reduced from (49.47 +/- 2.70)% to (14.61 +/- 0.81)% after Ex-4 treatment (0.4 mu g/ml) 12 h after OGD (P < 0.001). Moreover, immunofluorescence staining indicated that Ex-4 increased glucose-regulated proteins 78 (GRP78) and reduced C/EBP-homologous protein (CHOP). Western blot analysis demonstrated that, after neurons were treated with Ex-4, GRP78 was up-regulated over time (P < 0.01, vs. OGD group), while CHOP levels rose to a peak 8 h after OGD and then decreased (P < 0.05, vs. OGD group). This effect was changed by both the protein kinase A (PKA) inhibitor H89 (P < 0.01, P < 0.05, respectively, vs. Ex-4 group) and the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 (P < 0.01, P < 0.01, respectively, vs. Ex-4 group) but not by the mitogen-activated protein kinase (MAPK) inhibitor U0126. Our study also revealed that, compared with the Ex-4 group, inhibition of the PKA signaling pathway significantly decreased the survival rate of neurons, down-regulated the expression of B-cell lymphoma 2 (Bcl-2) and up-regulated the Bax expression 3 h after ODG (P < 0.05, P < 0.01, respectively), while neither PI3K nor MAPK inhibition exerted such effects. Furthermore, Western blotting exhibited that PKA expression was elevated in the presence or absence of OGD insults (P < 0.05). This study indicated that Ex-4 protected neurons against OGD by modulating the unfolded protein response (UPR) through the PKA pathway and may serve as a novel therapeutic agent for stroke. (c) 2012 IBRO. Published by Elsevier Ltd. All rights reserved.
基金：
Program of National Natural Science Foundation of China [81070938, 81101905]; Program for New Century Excellent Talents in University [NCET-10-0406]; Fundamental Research Funds for the Central Universities [HUST 2010JC028]
第一作者单位：[1]Huazhong Univ Sci & Technol, Dept Neurol, Union Hosp, Tongji Med Coll, Wuhan 430022, Peoples R China
通讯作者：
通讯机构：[1]Huazhong Univ Sci & Technol, Dept Neurol, Union Hosp, Tongji Med Coll, Wuhan 430022, Peoples R China[2]Huazhong Univ Sci & Technol, Key Lab Neurol Dis, Minist Educ, Tongji Med Coll, Wuhan 430030, Peoples R China[*1]Huazhong Univ Sci & Technol, Dept Neurol, Union Hosp, Tongji Med Coll, Jiefang Ave, Wuhan 430022, Peoples R China
推荐引用方式(GB/T 7714)：
Wang M. -D.,Huang Y.,Zhang G. -P.,et al.EXENDIN-4 IMPROVED RAT CORTICAL NEURON SURVIVAL UNDER OXYGEN/GLUCOSE DEPRIVATION THROUGH PKA PATHWAY[J].NEUROSCIENCE.2012,226:388-396.doi:10.1016/j.neuroscience.2012.09.025.
APA：
Wang, M. -D.,Huang, Y.,Zhang, G. -P.,Mao, L.,Xia, Y. -P....&Hu, B..(2012).EXENDIN-4 IMPROVED RAT CORTICAL NEURON SURVIVAL UNDER OXYGEN/GLUCOSE DEPRIVATION THROUGH PKA PATHWAY.NEUROSCIENCE,226,
MLA：
Wang, M. -D.,et al."EXENDIN-4 IMPROVED RAT CORTICAL NEURON SURVIVAL UNDER OXYGEN/GLUCOSE DEPRIVATION THROUGH PKA PATHWAY".NEUROSCIENCE 226.(2012):388-396
