title: Activation of mGluR5 attenuates NMDA-induced neurotoxicity through disruption of the NMDAR-PSD-95 complex and preservation of mitochondrial function in differentiated PC12 cells.
abstract: Glutamate-mediated toxicity is implicated in various neuropathologic conditions, and activation of ionotropic and metabotropic glutamate receptors is considered to be the most important mechanism. It has been reported that pharmacological saturation of metabotropic glutamate receptors (mGluRs) can facilitate N-methyl-D-aspartate receptor (NMDAR) related signaling cascades, but the mechanism leading to mGluR-NMDAR interactions in excitotoxic neuronal injury has remained unidentified. In the present study, we investigated the role of mGluR5 in the regulation of N-methyl-D-aspartate (NMDA)-induced excitotoxicity in differentiated PC12 cells. We found that activation of mGluR5 with the specific agonist R,S-2-chloro-5-hydroxyphenylglycine (CHPG) increased cell viability and inhibited lactate dehydrogenase (LDH) release in a dose-dependent manner. CHPG also inhibited an increase in the Bax/Bcl-2 ratio, attenuated cleavage of caspase-9 and caspase-3, and reduced apoptotic cell death after NMDA treatment. The NMDA-induced mitochondrial dysfunction, as indicated by mitochondrial reactive oxygen species (ROS) generation, collapse of mitochondrial membrane potential (MMP), and cytochrome c release, was also partly prevented by CHPG treatment. Furthermore, CHPG blocked the NMDA-induced interaction of NMDAR with postsynaptic density protein-95 (PSD-95), but had no effects on intracellular calcium concentrations. All these results indicated that activation of mGluR5 protects differentiated PC12 cells from NMDA-induced neuronal excitotoxicity by disrupting NMDAR-PSD-95 interaction, which might be an ideal target for investigating therapeutic strategies in various neurological diseases where excitotoxicity may contribute to their pathology.
authors.affiliation: Department of Neurosurgery, Xijing Institute of Clinical Neuroscience, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China. fmmudaishuhui@163.com.
authors.forename: Shu-Hui
authors.initials: SH
authors.lastname: Dai
authors.affiliation: Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China. fmmuqinna@163.com.
authors.forename: Na
authors.initials: N
authors.lastname: Qin
authors.affiliation: Department of Neurosurgery, Xijing Institute of Clinical Neuroscience, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China. fmmuchentao@163.com.
authors.forename: Tao
authors.initials: T
authors.lastname: Chen
authors.affiliation: Department of Neurosurgery, Xijing Institute of Clinical Neuroscience, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China. fmmuluopeng@163.com.
authors.forename: Peng
authors.initials: P
authors.lastname: Luo
authors.affiliation: Department of Neurosurgery, Xijing Institute of Clinical Neuroscience, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China. fmmuzhanglei@163.com.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Neurosurgery, Xijing Institute of Clinical Neuroscience, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China. fmmuraowei@163.com.
authors.forename: Wei
authors.initials: W
authors.lastname: Rao
authors.affiliation: Department of Neurosurgery, Xijing Institute of Clinical Neuroscience, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China. fmmuyangyf@126.com.
authors.forename: Yue-Fan
authors.initials: YF
authors.lastname: Yang
authors.affiliation: Department of Neurosurgery, Xijing Institute of Clinical Neuroscience, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China. fmmujiangxiaofan@163.com.
authors.forename: Xiao-Fan
authors.initials: XF
authors.lastname: Jiang
authors.affiliation: Department of Neurosurgery, Xijing Institute of Clinical Neuroscience, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China. zhoufei@fmmu.edu.cn.
authors.forename: Zhou
authors.initials: Z
authors.lastname: Fei
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002118:Calcium / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D045304:Cytochromes c / Q000378:metabolism; D000076122:Disks Large Homolog 4 Protein; D005998:Glycine / Q000031:analogs & derivatives / Q000494:pharmacology; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008565:Membrane Proteins / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism*; D016202:N-Methylaspartate / Q000633:toxicity; D016716:PC12 Cells; D010648:Phenylacetates / Q000494:pharmacology; D011485:Protein Binding; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism; D064529:Receptor, Metabotropic Glutamate 5 / Q000819:agonists / Q000378:metabolism*; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism*; D013237:Stereoisomerism
chemical_list: C107349:2-chloro-5-hydroxyphenylglycine; D000076122:Disks Large Homolog 4 Protein; C501449:Dlg4 protein, rat; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D010648:Phenylacetates; D017382:Reactive Oxygen Species; D064529:Receptor, Metabotropic Glutamate 5; D016194:Receptors, N-Methyl-D-Aspartate; D016202:N-Methylaspartate; D045304:Cytochromes c; D002118:Calcium; D005998:Glycine