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Exendin-4 improved rat cortical neuron survival under oxygen/glucose deprivation through PKA pathway.
Neuroscience. 2012 Dec 13; 226:388-96.N

Abstract

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 μg/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 μg/ml) 12h 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 8h 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 3h 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.

Authors+Show Affiliations

Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Jiefang Avenue, Wuhan 430022, PR China.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

23000625

Citation

Wang, M-D, et al. "Exendin-4 Improved Rat Cortical Neuron Survival Under Oxygen/glucose Deprivation Through PKA Pathway." Neuroscience, vol. 226, 2012, pp. 388-96.
Wang MD, Huang Y, Zhang GP, et al. Exendin-4 improved rat cortical neuron survival under oxygen/glucose deprivation through PKA pathway. Neuroscience. 2012;226:388-96.
Wang, M. D., Huang, Y., Zhang, G. P., Mao, L., Xia, Y. P., Mei, Y. W., & Hu, B. (2012). Exendin-4 improved rat cortical neuron survival under oxygen/glucose deprivation through PKA pathway. Neuroscience, 226, 388-96. https://doi.org/10.1016/j.neuroscience.2012.09.025
Wang MD, et al. Exendin-4 Improved Rat Cortical Neuron Survival Under Oxygen/glucose Deprivation Through PKA Pathway. Neuroscience. 2012 Dec 13;226:388-96. PubMed PMID: 23000625.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Exendin-4 improved rat cortical neuron survival under oxygen/glucose deprivation through PKA pathway. AU - Wang,M-D, AU - Huang,Y, AU - Zhang,G-P, AU - Mao,L, AU - Xia,Y-P, AU - Mei,Y-W, AU - Hu,B, Y1 - 2012/09/19/ PY - 2012/04/19/received PY - 2012/09/01/revised PY - 2012/09/11/accepted PY - 2012/9/25/entrez PY - 2012/9/25/pubmed PY - 2013/4/23/medline SP - 388 EP - 96 JF - Neuroscience JO - Neuroscience VL - 226 N2 - 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 μg/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 μg/ml) 12h 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 8h 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 3h 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. SN - 1873-7544 UR - https://www.unboundmedicine.com/medline/citation/23000625/Exendin_4_improved_rat_cortical_neuron_survival_under_oxygen/glucose_deprivation_through_PKA_pathway_ L2 - https://www.clinicalkey.com/content/playBy/pii?v=S0306-4522(12)00933-5 DB - PRIME DP - Unbound Medicine ER -