Activation of type 5 metabotropic glutamate receptor promotes the proliferation of rat retinal progenitor cell via activation of the PI-3-K and MAPK signaling pathways. (13th May 2016)

• Record Type: Journal Article
• Authors: Zhang, Z.; Hu, F.; Liu, Y.; Ma, B.; Chen, X.; Zhu, K.; Shi, Y.; Wei, T.; Xing, Y.; Gao, Y.; Lu, H.; Liu, Y.; Kang, Q.
• Is Part Of: Neuroscience. Volume 322(2016)
• Page Start: 138
• Page End: 151
• Publication Date: 2016-05-13
• Subjects: AKT protein kinase B -- AMD age-related macular degeneration -- bFGF basic fibroblast growth factor -- BrdU 5-Bromo-2-deoxyUridine -- DHPG (S)-3, 5-dihydroxyphenylglycine hydrate -- DMEM/F12 Dulbecco's Modified Eagle's Medium and Hams F12 -- EGF epidermal growth factor -- ERKs extracellular signal-regulated protein kinases -- ES embryonic stem cells -- FACS fluorescence activated cell sorting -- MAPKs mitogen-activated protein kinases -- mGluRs metabotropic glutamate receptors -- MTEP 6-methyl-2-(phenylethynyl)pyridine hydrochloride -- MTT 3-((2-methyl-1, 3-thiazol-4-yl)ethynyl)pyridine hydrochloride -- NSCs neural stem cells -- PDGF platelet-derived growth factor -- PBS phosphate-buffered saline -- PFA paraformaldehyde -- PI propidium iodide -- PI-3-K phosphatidylinositol-3-kinase -- PKC protein kinase C -- RP retinitis pigmentosa -- RPCs retinal stem/progenitor cells -- RPE retinal pigment epithelial cells -- RT room temperature -- SDS–PAGE sodium dodecyl sulfate–polyacrylamide gel electrophoresis -- TUNEL terminal-deoxynucleotidyltransferase-mediated UTP nick end labeling; retinal progenitor cells -- metabotropic glutamate receptor 5 -- proliferation -- mitogen-activated protein kinases -- phosphatidylinositol-3-kinase; Neurochemistry -- Periodicals; Neurophysiology -- Periodicals; Neurology -- Periodicals; Neurochimie -- Périodiques; Neurophysiologie -- Périodiques; Neurochemistry; Neurophysiology; Electronic journals; Periodicals; Electronic journals; 612.8
• DOI: 10.1016/j.neuroscience.2016.02.030
• Languages: English
• ISSNs: 0306-4522

Abstract

Highlights: Our research illuminates the relationship between mGluR5 and RPCs. mGluR5 promotes the proliferation of RPCs and enhances the expression of Cyclin D1. mGluR5 promotes the proliferation of RPCs via activation of the PI-3-K and MAPK signaling pathways. Abstract: The metabotropic glutamate receptor 5 (mGluR5) regulates neurogenesis in the brain, but the effect of mGluR5 on retinal progenitor cells (RPCs) remains unknown. In this study, we found that mGluR5 promoted the proliferation of rat RPCs with activation of the phosphatidylinositol-3-kinase (PI-3-K) and mitogen-activated protein kinase (MAPK) signaling pathways in vitro . The mGluR5 agonist (S)-3, 5-dihydroxyphenylglycine hydrate (DHPG) increased the cellular viability in a concentration- and time-dependent manner, whereas the mGluR5 antagonist 6-methyl-2-(phenylethynyl)pyridine hydrochloride (MTEP) had the opposite effect, as shown by 3-((2-methyl-1, 3-thiazol-4-yl)ethynyl)pyridine hydrochloride (MTT) assay. Treatment with DHPG (100 μM) also promoted the proliferation of RPCs, as indicated by 5-Bromo-2-deoxyUridine (BrdU) staining and flow cytometry, and likewise, MTEP (100 μM) and mGluR5 knockdown abolished the action of mGluR5 activity. Western blot demonstrated that the activation of mGluR5 enhanced the expression of Cyclin D1 and the phosphorylation level of PKC however, MTEP or mGluR5 knockdown also abrogated the effect of DHPG on RPCs. Furthermore, we found that activation of the extracellular signal-regulated protein kinase (ERK) and protein kinase B (AKT) signaling pathways was involved in the proliferation of RPC. After DHPG treatment, the levels of both p-ERK1/2 and p-AKT increased in a time-dependent manner. Then we used MTEP, mGluR5 knockdown, the ERK1/2 inhibitor U0126 and the AKT inhibitor LY294002 to pretreat the cells, and all of them clearly eliminated the influence of DHPG. These results demonstrated that mGluR5 regulates neurogenesis in RPCs through the MAPK and PI-3-K signaling pathways, and these findings may motivate a pharmacological study investigating a potential mechanism for the treatment of retinal diseases such as retinitis pigmentosa (RP) and age-related macular degeneration (AMD).