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Shifting towards a model of mGluR5 dysregulation in schizophrenia: Consequences for future schizophrenia treatment. Neuropharmacology 2015; 115:73-91. [PMID: 26349010 DOI: 10.1016/j.neuropharm.2015.08.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Revised: 08/02/2015] [Accepted: 08/03/2015] [Indexed: 12/22/2022]
Abstract
Metabotropic glutamate receptor subtype 5 (mGluR5), encoded by the GRM5 gene, represents a compelling novel drug target for the treatment of schizophrenia. mGluR5 is a postsynaptic G-protein coupled glutamate receptor strongly linked with several critical cellular processes that are reported to be disrupted in schizophrenia. Accordingly, mGluR5 positive allosteric modulators show encouraging therapeutic potential in preclinical schizophrenia models, particularly for the treatment of cognitive dysfunctions against which currently available therapeutics are largely ineffective. More work is required to support the progression of mGluR5-targeting drugs into the clinic for schizophrenia treatment, although some obstacles may be overcome by comprehensively understanding how mGluR5 itself is involved in the neurobiology of the disorder. Several processes that are necessary for the regulation of mGluR5 activity have been identified, but not examined, in the context of schizophrenia. These processes include protein-protein interactions, dimerisation, subcellular trafficking, the impact of genetic variability or mutations on protein function, as well as epigenetic, post-transcriptional and post-translational processes. It is essential to understand these aspects of mGluR5 to determine whether they are affected in schizophrenia pathology, and to assess the consequences of mGluR5 dysfunction for the future use of mGluR5-based drugs. Here, we summarise the known processes that regulate mGluR5 and those that have already been studied in schizophrenia, and discuss the consequences of this dysregulation for current mGluR5 pharmacological strategies. This article is part of the Special Issue entitled 'Metabotropic Glutamate Receptors, 5 years on'.
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Matosin N, Fernandez-Enright F, Fung SJ, Lum JS, Engel M, Andrews JL, Huang XF, Weickert CS, Newell KA. Alterations of mGluR5 and its endogenous regulators Norbin, Tamalin and Preso1 in schizophrenia: towards a model of mGluR5 dysregulation. Acta Neuropathol 2015; 130:119-29. [PMID: 25778620 DOI: 10.1007/s00401-015-1411-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 03/09/2015] [Accepted: 03/09/2015] [Indexed: 12/30/2022]
Abstract
Knockout of genes encoding metabotropic glutamate receptor 5 (mGluR5) or its endogenous regulators, such as Norbin, induce a schizophrenia-like phenotype in rodents, suggesting dysregulation of mGluR5 in schizophrenia. Human genetic and pharmacological animal studies support this hypothesis, but no studies have explored mGluR5 dysfunction at the molecular level in the postmortem schizophrenia brain. We assessed mGluR5 mRNA and protein levels in the dorsolateral prefrontal cortex (DLPFC) using a large cohort of schizophrenia and control subjects (n = 37/group), and additionally measured protein levels of recently discovered mGluR5 endogenous regulators, Norbin (neurochondrin), Tamalin (GRASP-1), and Preso1 (FRMPD4), which regulate mGluR5 localization, internalization and signaling. While mGluR5 mRNA expression was unchanged, mGluR5 protein levels were significantly higher in schizophrenia subjects compared to controls (total: +22%; dimer: +54%; p < 0.001). Conversely, mGluR5 regulatory proteins were expressed at lower levels in schizophrenia subjects compared to controls (Norbin -37%, p < 0.001; Tamalin -30%, p = 0.084; Preso1 -29%, p = 0.001). mGluR5 protein was significantly associated with mGluR5 mRNA and mGluR5 endogenous regulators in control subjects, but these associations were lost in schizophrenia subjects. Lastly, there were no associations between protein measures and lifetime antipsychotic history in schizophrenia subjects. To confirm no antipsychotic influence, all proteins were measured in the prefrontal cortex of rats exposed to haloperidol or olanzapine; there were no effects of antipsychotic drug treatment on mGluR5, Norbin, Tamalin or Preso1. The results from our study provide compelling evidence that mGluR5 regulation is altered in schizophrenia, likely contributing to the altered glutamatergic signaling that is associated with the disorder.
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Affiliation(s)
- Natalie Matosin
- Faculty of Science, Medicine and Health, University of Wollongong, Northfields Ave, Wollongong, NSW, 2522, Australia
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Biased mGlu5-Positive Allosteric Modulators Provide In Vivo Efficacy without Potentiating mGlu5 Modulation of NMDAR Currents. Neuron 2015; 86:1029-1040. [PMID: 25937172 DOI: 10.1016/j.neuron.2015.03.063] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 02/22/2015] [Accepted: 03/24/2015] [Indexed: 12/14/2022]
Abstract
Schizophrenia is associated with disruptions in N-methyl-D-aspartate glutamate receptor subtype (NMDAR)-mediated excitatory synaptic signaling. The metabotropic glutamate receptor subtype 5 (mGlu5) is a closely associated signaling partner with NMDARs and regulates NMDAR function in forebrain regions implicated in the pathology of schizophrenia. Efficacy of mGlu5 positive allosteric modulators (PAMs) in animal models of psychosis and cognition was previously attributed to potentiation of NMDAR function. To directly test this hypothesis, we identified VU0409551 as a novel mGlu5 PAM that exhibits distinct stimulus bias and selectively potentiates mGlu5 coupling to Gαq-mediated signaling but not mGlu5 modulation of NMDAR currents or NMDAR-dependent synaptic plasticity in the rat hippocampus. Interestingly, VU0409551 produced robust antipsychotic-like and cognition-enhancing activity in animal models. These data provide surprising new mechanistic insights into the actions of mGlu5 PAMs and suggest that modulation of NMDAR currents is not critical for in vivo efficacy. VIDEO ABSTRACT.
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Lindemann L, Porter RH, Scharf SH, Kuennecke B, Bruns A, von Kienlin M, Harrison AC, Paehler A, Funk C, Gloge A, Schneider M, Parrott NJ, Polonchuk L, Niederhauser U, Morairty SR, Kilduff TS, Vieira E, Kolczewski S, Wichmann J, Hartung T, Honer M, Borroni E, Moreau JL, Prinssen E, Spooren W, Wettstein JG, Jaeschke G. Pharmacology of Basimglurant (RO4917523, RG7090), a Unique Metabotropic Glutamate Receptor 5 Negative Allosteric Modulator in Clinical Development for Depression. J Pharmacol Exp Ther 2015; 353:213-33. [DOI: 10.1124/jpet.114.222463] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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Takayanagi H, Yuzawa S, Sumimoto H. Structural basis for the recognition of the scaffold protein Frmpd4/Preso1 by the TPR domain of the adaptor protein LGN. Acta Crystallogr F Struct Biol Commun 2015; 71:175-83. [PMID: 25664792 PMCID: PMC4321472 DOI: 10.1107/s2053230x14028143] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2014] [Accepted: 12/26/2014] [Indexed: 12/19/2022] Open
Abstract
The adaptor protein LGN interacts via the N-terminal domain comprising eight tetratricopeptide-repeat (TPR) motifs with its partner proteins mInsc, NuMA, Frmpd1 and Frmpd4 in a mutually exclusive manner. Here, the crystal structure of the LGN TPR domain in complex with human Frmpd4 is described at 1.5 Å resolution. In the complex, the LGN-binding region of Frmpd4 (amino-acid residues 990-1011) adopts an extended structure that runs antiparallel to LGN along the concave surface of the superhelix formed by the TPR motifs. Comparison with the previously determined structures of the LGN-Frmpd1, LGN-mInsc and LGN-NuMA complexes reveals that these partner proteins interact with LGN TPR1-6 via a common core binding region with consensus sequence (E/Q)XEX4-5(E/D/Q)X1-2(K/R)X0-1(V/I). In contrast to Frmpd1, Frmpd4 makes additional contacts with LGN via regions N- and C-terminal to the core sequence. The N-terminal extension is replaced by a specific α-helix in mInsc, which drastically increases the direct contacts with LGN TPR7/8, consistent with the higher affinity of mInsc for LGN. A crystal structure of Frmpd4-bound LGN in an oxidized form is also reported, although oxidation does not appear to strongly affect the interaction with Frmpd4.
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Affiliation(s)
- Hiroki Takayanagi
- Department of Biochemistry, Kyushu University Graduate School of Medical Sciences, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Satoru Yuzawa
- Department of Biochemistry, Kyushu University Graduate School of Medical Sciences, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Hideki Sumimoto
- Department of Biochemistry, Kyushu University Graduate School of Medical Sciences, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
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56
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Jong YJI, Sergin I, Purgert CA, O'Malley KL. Location-dependent signaling of the group 1 metabotropic glutamate receptor mGlu5. Mol Pharmacol 2014; 86:774-85. [PMID: 25326002 DOI: 10.1124/mol.114.094763] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Although G protein-coupled receptors are primarily known for converting extracellular signals into intracellular responses, some receptors, such as the group 1 metabotropic glutamate receptor, mGlu5, are also localized on intracellular membranes where they can mediate both overlapping and unique signaling effects. Thus, besides "ligand bias," whereby a receptor's signaling modality can shift from G protein dependence to independence, canonical mGlu5 receptor signaling can also be influenced by "location bias" (i.e., the particular membrane and/or cell type from which it signals). Because mGlu5 receptors play important roles in both normal development and in disorders such as Fragile X syndrome, autism, epilepsy, addiction, anxiety, schizophrenia, pain, dyskinesias, and melanoma, a large number of drugs are being developed to allosterically target this receptor. Therefore, it is critical to understand how such drugs might be affecting mGlu5 receptor function on different membranes and in different brain regions. Further elucidation of the site(s) of action of these drugs may determine which signal pathways mediate therapeutic efficacy.
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Affiliation(s)
- Yuh-Jiin I Jong
- Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri
| | - Ismail Sergin
- Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri
| | - Carolyn A Purgert
- Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri
| | - Karen L O'Malley
- Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri
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Lee ES, Kim WR, Kim Y, Lee HW, Kim H, Sun W. Polarized and Stage-Dependent Distribution of Immunoreactivity for Novel PDZ-Binding Protein Preso1 in Adult Neurogenic Regions. Endocrinol Metab (Seoul) 2014; 29:349-55. [PMID: 25309794 PMCID: PMC4192811 DOI: 10.3803/enm.2014.29.3.349] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Revised: 11/03/2013] [Accepted: 01/13/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Adult neural stem cells have the potential for self-renewal and differentiation into multiple cell lineages via symmetric or asymmetric cell division. Preso1 is a recently identified protein involved in the formation of dendritic spines and the promotion of axonal growth in developing neurons. Preso1 can also bind to cell polarity proteins, suggesting a potential role for Preso1 in asymmetric cell division. METHODS To investigate the distribution of Preso1, we performed immunohistochemistry with adult mouse brain slice. Also, polarized distribution of Preso1 was assessed by immunocytochemistry in cultured neural stem cells. RESULTS Immunoreactivity for Preso1 (Preso1-IR) was strong in the rostral migratory stream and subventricular zone, where proliferating transit-amplifying cells and neuroblasts are prevalent. In cultured neural stem cells, Preso1-IR was unequally distributed in the cell cytosol. We also observed the distribution of Preso1 in the subgranular zone of the hippocampal dentate gyrus, another neurogenic region in the adult brain. Interestingly, Preso1-IR was transiently observed in the nuclei of doublecortin-expressing neuroblasts immediately after asymmetric cell division. CONCLUSION Our study demonstrated that Preso1 is asymmetrically distributed in the cytosol and nuclei of neural stem/progenitor cells in the adult brain, and may play a significant role in cell differentiation via association with cell polarity machinery.
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Affiliation(s)
- Eun Soo Lee
- Department of Anatomy, BK21 Program, Korea University College of Medicine, Seoul, Korea
| | - Woon Ryoung Kim
- Department of Anatomy, BK21 Program, Korea University College of Medicine, Seoul, Korea
| | - Younghwa Kim
- Department of Emergency Medical Technology, Kyungil University College of Nursing and Public Health, Gyeongsan, Korea
| | - Hyun Woo Lee
- Department of Anatomy, BK21 Program, Korea University College of Medicine, Seoul, Korea
| | - Hyun Kim
- Department of Anatomy, BK21 Program, Korea University College of Medicine, Seoul, Korea
| | - Woong Sun
- Department of Anatomy, BK21 Program, Korea University College of Medicine, Seoul, Korea
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de Bartolomeis A, Buonaguro EF, Iasevoli F, Tomasetti C. The emerging role of dopamine-glutamate interaction and of the postsynaptic density in bipolar disorder pathophysiology: Implications for treatment. J Psychopharmacol 2014; 28:505-26. [PMID: 24554693 DOI: 10.1177/0269881114523864] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Aberrant synaptic plasticity, originating from abnormalities in dopamine and/or glutamate transduction pathways, may contribute to the complex clinical manifestations of bipolar disorder (BD). Dopamine and glutamate systems cross-talk at multiple levels, such as at the postsynaptic density (PSD). The PSD is a structural and functional protein mesh implicated in dopamine and glutamate-mediated synaptic plasticity. Proteins at PSD have been demonstrated to be involved in mood disorders pathophysiology and to be modulated by antipsychotics and mood stabilizers. On the other side, post-receptor effectors such as protein kinase B (Akt), glycogen synthase kinase-3 (GSK-3) and the extracellular signal-regulated kinase (Erk), which are implicated in both molecular abnormalities and treatment of BD, may interact with PSD proteins, and participate in the interplay of the dopamine-glutamate signalling pathway. In this review, we describe emerging evidence on the molecular cross-talk between dopamine and glutamate signalling in BD pathophysiology and pharmacological treatment, mainly focusing on dysfunctions in PSD molecules. We also aim to discuss future therapeutic strategies that could selectively target the PSD-mediated signalling cascade at the crossroads of dopamine-glutamate neurotransmission.
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Affiliation(s)
- Andrea de Bartolomeis
- Laboratory of Molecular and Translational Psychiatry, Department of Neuroscience, Section of Psychiatry, University Medical School of Naples "Federico II", Naples, Italy
| | - Elisabetta F Buonaguro
- Laboratory of Molecular and Translational Psychiatry, Department of Neuroscience, Section of Psychiatry, University Medical School of Naples "Federico II", Naples, Italy
| | - Felice Iasevoli
- Laboratory of Molecular and Translational Psychiatry, Department of Neuroscience, Section of Psychiatry, University Medical School of Naples "Federico II", Naples, Italy
| | - Carmine Tomasetti
- Laboratory of Molecular and Translational Psychiatry, Department of Neuroscience, Section of Psychiatry, University Medical School of Naples "Federico II", Naples, Italy
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59
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Fischer MJM, McNaughton PA. How anchoring proteins shape pain. Pharmacol Ther 2014; 143:316-22. [PMID: 24727631 DOI: 10.1016/j.pharmthera.2014.04.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Accepted: 03/28/2014] [Indexed: 11/29/2022]
Abstract
Cellular responsiveness to external stimuli can be altered by extracellular mediators which activate membrane receptors, in turn signalling to the intracellular space via calcium, cyclic nucleotides, membrane lipids or enzyme activity. These signalling events trigger a cascade leading to an effector which can be a channel, an enzyme or a transcription factor. The effectiveness of these intracellular events is enhanced when they are maintained in close proximity by anchoring proteins, which assemble complexes of signalling molecules such as kinases together with their targets, and in this way enhance both the speed and the precision of intracellular signalling. The A kinase anchoring protein (AKAP) family are adaptor proteins originally named for their ability to associate Protein Kinase A and its targets, but several other enzymes bound by AKAPs have now been found and a wide variety of target structures has been described. This review provides an overview of anchoring proteins involved in pain signalling. The key anchoring proteins and their ion channel targets in primary sensory neurons responding to painful stimuli (nociceptors) are discussed.
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Affiliation(s)
- Michael J M Fischer
- Institute of Physiology and Pathophysiology, FAU Erlangen-Nürnberg, Germany.
| | - Peter A McNaughton
- Wolfson Centre for Age-Related Research, Hodgkin Building, King's College London, London SE1 1UH, UK
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60
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Luo P, Chen T, Zhao Y, Zhang L, Yang Y, Liu W, Li S, Rao W, Dai S, Yang J, Fei Z. Postsynaptic scaffold protein Homer 1a protects against traumatic brain injury via regulating group I metabotropic glutamate receptors. Cell Death Dis 2014; 5:e1174. [PMID: 24722299 PMCID: PMC5424101 DOI: 10.1038/cddis.2014.116] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2013] [Revised: 02/11/2014] [Accepted: 02/19/2014] [Indexed: 12/22/2022]
Abstract
Traumatic brain injury (TBI) produces excessive glutamate, leading to excitotoxicity via the activation of glutamate receptors. Postsynaptic density scaffold proteins have crucial roles in mediating signal transduction from glutamate receptors to their downstream mediators. Therefore, studies on the mechanisms underlying regulation of excitotoxicity by scaffold proteins can uncover new treatments for TBI. Here, we demonstrated that the postsynaptic scaffold protein Homer 1a was neuroprotective against TBI in vitro and in vivo, and this neuroprotection was associated with its effects on group I metabotropic glutamate receptors (mGluRs). Upon further study, we found that Homer 1a mainly affected neuronal injury induced by mGluR1 activation after TBI and also influenced mGluR5 function when its activity was restored. The ability of Homer 1a to disrupt mGluR-ERK signaling contributed to its ability to regulate the functions of mGluR1 and mGluR5 after traumatic injury. Intracellular Ca(2+) and PKC were two important factors involved in the mediation of mGluR-ERK signaling by Homer 1a. These results define Homer 1a as a novel endogenous neuroprotective agent against TBI.
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Affiliation(s)
- P Luo
- Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, People's Republic of China
| | - T Chen
- Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, People's Republic of China
| | - Y Zhao
- Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, People's Republic of China
| | - L Zhang
- Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, People's Republic of China
| | - Y Yang
- Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, People's Republic of China
| | - W Liu
- Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, People's Republic of China
| | - S Li
- Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, People's Republic of China
| | - W Rao
- Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, People's Republic of China
| | - S Dai
- Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, People's Republic of China
| | - J Yang
- Department of Surgery, Boston Veterans Affairs Healthcare System, Boston University School of Medicine, Boston, MA, USA
| | - Z Fei
- Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, People's Republic of China
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61
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Partridge JG, Lewin AE, Yasko JR, Vicini S. Contrasting actions of group I metabotropic glutamate receptors in distinct mouse striatal neurones. J Physiol 2014; 592:2721-33. [PMID: 24710062 DOI: 10.1113/jphysiol.2014.272773] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
In mouse striatum, metabotropic glutamate receptor (mGluR) activation leads to several modulatory effects in synaptic transmission. These effects range from dampening of glutamate release from excitatory terminals to depolarization of divergent classes of interneurones. We compared the action of group I mGluR activation on several populations of striatal neurones using a combination of genetic identification, electrophysiology, and Ca(2+) imaging techniques. Patch-clamp recordings from spiny projection neurones (SPNs) and various interneurone populations demonstrated that the group I mGluR agonist (RS)-3,5-dihydroxyphenylglycine (DHPG) robustly depolarizes several interneurone classes that form GABAergic synapses onto SPNs. We further utilized the genetic reporter mouse strain Ai38, which expresses the calcium indicator protein GCaMP3 in a Cre-dependent manner. Breeding Ai38 mice with various neurone selective, promoter-driven Cre recombinase mice resulted in GCaMP3 expression in defined cell populations in striatum. Consistent with our electrophysiological findings, group I agonist applications increased intracellular levels of calcium ([Ca(2+)]i) in all interneurone populations tested. We also found that acute DHPG application evoked a transient, rapid increase in [Ca(2+)]i from only a small percentage of identifiable SPNs. Surprisingly, this fast [Ca(2+)]i response exhibited a robust enhancement or sensitization, in a calcium-dependent fashion. Following several procedures to increase [Ca(2+)]i, the vast majority of SPNs responded with rapid changes in [Ca(2+)]i to mGluR agonists in a time-dependent fashion. These findings extend our understanding on group I mGluR influence of striatal output via powerful, local GABAergic connections in addition to [Ca(2+)]i dynamics that impact on activity or spike-timing-dependent forms of synaptic plasticity.
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Affiliation(s)
- John G Partridge
- Department of Pharmacology and Physiology, Georgetown University School of Medicine, Washington, DC, 20007, USA Interdisciplinary Program in Neuroscience, Georgetown University School of Medicine, Washington, DC, 20007, USA
| | - Amanda E Lewin
- Department of Pharmacology and Physiology, Georgetown University School of Medicine, Washington, DC, 20007, USA
| | - Jessica R Yasko
- Department of Pharmacology and Physiology, Georgetown University School of Medicine, Washington, DC, 20007, USA
| | - Stefano Vicini
- Department of Pharmacology and Physiology, Georgetown University School of Medicine, Washington, DC, 20007, USA Interdisciplinary Program in Neuroscience, Georgetown University School of Medicine, Washington, DC, 20007, USA
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D'Antoni S, Spatuzza M, Bonaccorso CM, Musumeci SA, Ciranna L, Nicoletti F, Huber KM, Catania MV. Dysregulation of group-I metabotropic glutamate (mGlu) receptor mediated signalling in disorders associated with Intellectual Disability and Autism. Neurosci Biobehav Rev 2014; 46 Pt 2:228-41. [PMID: 24548786 DOI: 10.1016/j.neubiorev.2014.02.003] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 01/13/2014] [Accepted: 02/06/2014] [Indexed: 12/11/2022]
Abstract
Activation of group-I metabotropic glutamate receptors, mGlu1 and mGlu5, triggers a variety of signalling pathways in neurons and glial cells, which are differently implicated in synaptic plasticity. The earliest and much of key studies discovered abnormal mGlu5 receptor function in Fragile X syndrome (FXS) mouse models which then motivated more recent work that finds mGlu5 receptor dysfunction in related disorders such as intellectual disability (ID), obsessive-compulsive disorder (OCD) and autism. Therefore, mGlu1/5 receptor dysfunction may represent a common aetiology of these complex diseases. Furthermore, many studies have focused on dysregulation of mGlu5 signalling to synaptic protein synthesis. However, emerging evidence finds abnormal mGlu5 receptor interactions with its scaffolding proteins in FXS which results in mGlu5 receptor dysfunction and phenotypes independent of signalling to protein synthesis. Finally, both an increased and reduced mGlu5 functioning seem to be associated with ID and autism spectrum disorders, with important consequences for potential treatment of these developmental disorders.
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Affiliation(s)
- Simona D'Antoni
- Institute of Neurological Sciences, the National Research Council of Italy (CNR), Catania, Italy
| | - Michela Spatuzza
- Institute of Neurological Sciences, the National Research Council of Italy (CNR), Catania, Italy
| | | | | | - Lucia Ciranna
- Department of Biomedical Sciences, section of Physiology, University of Catania, Italy
| | - Ferdinando Nicoletti
- IRCCS Neuromed, Pozzilli (IS), Italy; University of Rome La Sapienza, Rome, Italy
| | - Kimberly M Huber
- University of Texas Southwestern Medical Center, Department of Neuroscience, Dallas, TX 75390-9111, USA
| | - Maria Vincenza Catania
- Institute of Neurological Sciences, the National Research Council of Italy (CNR), Catania, Italy; IRCCS Oasi Maria SS, Troina (EN), Italy.
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Knackstedt LA, Trantham-Davidson HL, Schwendt M. The role of ventral and dorsal striatum mGluR5 in relapse to cocaine-seeking and extinction learning. Addict Biol 2014; 19:87-101. [PMID: 23710649 DOI: 10.1111/adb.12061] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Cocaine addiction is a chronic, relapsing disease characterized by an inability to regulate drug-seeking behavior. Here we investigated the role of mGluR5 in the ventral and dorsal striatum in regulating cocaine-seeking following both abstinence and extinction. Animals underwent 2 weeks of cocaine self-administration followed by 3 weeks of home-cage abstinence. Animals were then reintroduced to the operant chamber for a context-induced relapse test, followed by 7-10 days of extinction training. Once responding was extinguished, cue-primed reinstatement test was conducted. Both drug-seeking tests were conducted in the presence of either mGluR5 negative allosteric modulator, MTEP or vehicle infused into either the nucleus accumbens (NA) core or dorsolateral striatum (dSTR). We found that MTEP infused in the NA core attenuated both context-induced relapse following abstinence and cue-primed reinstatement following extinction training. Blocking dSTR mGluR5 had no effect on context- or cue-induced cocaine-seeking. However, the intra-dSTR MTEP infusion on the context-induced relapse test day attenuated extinction learning for 4 days after the infusion. Furthermore, mGluR5 surface expression was reduced and LTD was absent in dSTR slices of animals undergoing 3 weeks of abstinence from cocaine but not sucrose self-administration. LTD was restored by bath application of VU-29, a positive allosteric modulator of mGluR5. Bath application of MTEP prevented the induction of LTD in dSTR slices from sucrose animals. Taken together, this data indicates that dSTR mGluR5 plays an essential role in extinction learning but not cocaine relapse, while NA core mGluR5 modulates drug-seeking following both extinction and abstinence from cocaine self-administration.
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Affiliation(s)
- Lori A. Knackstedt
- Department of Neurosciences; Medical University of South Carolina; Charleston SC USA
| | | | - Marek Schwendt
- Department of Neurosciences; Medical University of South Carolina; Charleston SC USA
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64
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Synaptic depression via mGluR1 positive allosteric modulation suppresses cue-induced cocaine craving. Nat Neurosci 2013; 17:73-80. [PMID: 24270186 PMCID: PMC3971923 DOI: 10.1038/nn.3590] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Accepted: 10/31/2013] [Indexed: 01/25/2023]
Abstract
Cue-induced cocaine craving is a major cause of relapse in abstinent addicts. In rats, cue-induced craving progressively intensifies (incubates) during withdrawal from extended-access cocaine self-administration. After ~1 month of withdrawal, incubated craving is mediated by Ca2+-permeable AMPARs (CP-AMPARs) that accumulate in the nucleus accumbens (NAc). We found that decreased mGluR1 surface expression in the NAc precedes and enables CP-AMPAR accumulation. Thus, restoring mGluR1 tone by administering repeated injections of an mGluR1 positive allosteric modulator (PAM) prevented CP-AMPAR accumulation and incubation, whereas blocking mGluR1 transmission at even earlier withdrawal times accelerated CP-AMPAR accumulation. In studies conducted after prolonged withdrawal, when CP-AMPAR levels and cue-induced craving are high, we found that systemic administration of an mGluR1 PAM attenuated the expression of incubated craving by reducing CP-AMPAR transmission in the NAc to control levels. These results demonstrate a strategy whereby recovering addicts could use a systemically active compound to protect against cue-induced relapse.
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Park JM, Hu JH, Milshteyn A, Zhang PW, Moore CG, Park S, Datko MC, Domingo RD, Reyes CM, Wang XJ, Etzkorn FA, Xiao B, Szumlinski KK, Kern D, Linden DJ, Worley PF. A prolyl-isomerase mediates dopamine-dependent plasticity and cocaine motor sensitization. Cell 2013; 154:637-50. [PMID: 23911326 DOI: 10.1016/j.cell.2013.07.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Revised: 04/14/2013] [Accepted: 07/01/2013] [Indexed: 01/02/2023]
Abstract
Synaptic plasticity induced by cocaine and other drugs underlies addiction. Here we elucidate molecular events at synapses that cause this plasticity and the resulting behavioral response to cocaine in mice. In response to D1-dopamine-receptor signaling that is induced by drug administration, the glutamate-receptor protein metabotropic glutamate receptor 5 (mGluR5) is phosphorylated by microtubule-associated protein kinase (MAPK), which we show potentiates Pin1-mediated prolyl-isomerization of mGluR5 in instances where the product of an activity-dependent gene, Homer1a, is present to enable Pin1-mGluR5 interaction. These biochemical events potentiate N-methyl-D-aspartate receptor (NMDAR)-mediated currents that underlie synaptic plasticity and cocaine-evoked motor sensitization as tested in mice with relevant mutations. The findings elucidate how a coincidence of signals from the nucleus and the synapse can render mGluR5 accessible to activation with consequences for drug-induced dopamine responses and point to depotentiation at corticostriatal synapses as a possible therapeutic target for treating addiction.
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Affiliation(s)
- Joo Min Park
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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66
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Luo P, Yang Y, Liu W, Rao W, Bian H, Li X, Chen T, Liu M, Zhao Y, Dai S, Yan X, Fei Z. Downregulation of postsynaptic density-95-interacting regulator of spine morphogenesis reduces glutamate-induced excitotoxicity by differentially regulating glutamate receptors in rat cortical neurons. FEBS J 2013; 280:6114-27. [PMID: 24103031 DOI: 10.1111/febs.12531] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 09/08/2013] [Accepted: 09/12/2013] [Indexed: 01/03/2023]
Abstract
Glutamate-induced excitotoxicity is involved in many neurological diseases. Preso, a novel postsynaptic scaffold protein, mediates excitatory synaptic transmission and various synaptic functions. In this study, we investigated the role of Preso in the regulation of glutamate-induced excitotoxicity in rat cortical neurons. Knockdown of Preso with small interfering RNA improved neuronal viability and attenuated the elevation of lactate dehydrogenase (LDH) release after glutamate treatment. Downregulation of Preso also inhibited an increase in the BAX/Bcl-2 ratio and cleavage of caspase-9 and caspase-3. Although the expression and distribution of metabotropic glutamate receptor (mGluR) 1/5, NR1, NR2A and NR2B were not changed by knockdown of Preso, downregulation of Preso protected neurons from glutamate-induced excitotoxicity by inhibiting mGluR and N-methyl-D-aspartate receptor function. However, downregulation of Preso neither affected the expression of GluR1 and GluR2 nor influenced the function of α-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptor after glutamate treatment. Furthermore, intracellular Ca(2+) was an important downstream effector of Preso in the regulation of excitotoxicity. These results suggest that expression of Preso promotes the induction of excitotoxicity by facilitating different glutamate receptor signaling pathways. Therefore, Preso might be a potential pharmacological target for preventing and treating neurological diseases.
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Affiliation(s)
- Peng Luo
- Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China
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67
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Obara I, Goulding SP, Hu JH, Klugmann M, Worley PF, Szumlinski KK. Nerve injury-induced changes in Homer/glutamate receptor signaling contribute to the development and maintenance of neuropathic pain. Pain 2013; 154:1932-1945. [PMID: 23685007 DOI: 10.1016/j.pain.2013.03.035] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Revised: 02/12/2013] [Accepted: 03/26/2013] [Indexed: 11/28/2022]
Abstract
While group 1 metabotropic glutamate receptors (mGluRs) and ionotropic N-methyl-d-aspartate (NMDA) receptors regulate nociception, the precise molecular mechanism(s) contributing to glutamate signaling in chronic pain remain unclear. Here we not only confirmed the key involvement of Homer proteins in neuropathic pain, but also distinguished between the functional roles for different Homer family members and isoforms. Chronic constriction injury (CCI) of the sciatic nerve induced long-lasting, time-dependent increases in the postsynaptic density expression of the constitutively expressed (CC) isoforms Homer1b/c and/or Homer2a/b in the spinal dorsal horn and supraspinal structures involved in nociception (prefrontal cortex, thalamus), that co-occurred with increases in their associated mGluRs, NR2 subunits of the NMDA receptor, and the activation of downstream kinases. Virus-mediated overexpression of Homer1c and Homer2b after spinal (intrathecal) virus injection exacerbated CCI-induced mechanical and cold hypersensitivity, however, Homer1 and Homer2 gene knockout (KO) mice displayed no changes in their neuropathic phenotype. In contrast, overexpression of the immediate early gene (IEG) Homer1a isoform reduced, while KO of Homer1a gene potentiated neuropathic pain hypersensitivity. Thus, nerve injury-induced increases in CC-Homers expression promote pain in pathological states, but IEG-Homer induction protects against both the development and maintenance of neuropathy. Additionally, exacerbated pain hypersensitivity in transgenic mice with reduced Homer binding to mGluR5 supports also an inhibitory role for Homer interactions with mGluR5 in mediating neuropathy. Such data indicate that nerve injury-induced changes in glutamate receptor/Homer signaling contribute in dynamic but distinct ways to neuropathic pain processing, which has relevance for the etiology of chronic pain symptoms and its treatment.
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Affiliation(s)
- Ilona Obara
- Department of Psychology and The Neuroscience Research Institute, University of California at Santa Barbara, Santa Barbara, CA 93106-9660, USA School of Medicine, Pharmacy and Health, Durham University, Queens Campus, Stockton on Tees TS17 6BH, UK Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA Translational Neuroscience Facility, School of Medical Sciences, UNSW Kensington Campus, University of New South Wales, Sydney, NSW 2052, Australia
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68
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Obara I, Goulding SP, Gould AT, Lominac KD, Hu JH, Zhang PW, von Jonquieres G, Dehoff M, Xiao B, Seeburg PH, Worley PF, Klugmann M, Szumlinski KK. Homers at the Interface between Reward and Pain. Front Psychiatry 2013; 4:39. [PMID: 23761764 PMCID: PMC3675508 DOI: 10.3389/fpsyt.2013.00039] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Accepted: 05/10/2013] [Indexed: 11/13/2022] Open
Abstract
Pain alters opioid reinforcement, presumably via neuroadaptations within ascending pain pathways interacting with the limbic system. Nerve injury increases expression of glutamate receptors and their associated Homer scaffolding proteins throughout the pain processing pathway. Homer proteins, and their associated glutamate receptors, regulate behavioral sensitivity to various addictive drugs. Thus, we investigated a potential role for Homers in the interactions between pain and drug reward in mice. Chronic constriction injury (CCI) of the sciatic nerve elevated Homer1b/c and/or Homer2a/b expression within all mesolimbic structures examined and for the most part, the Homer increases coincided with elevated mGluR5, GluN2A/B, and the activational state of various down-stream kinases. Behaviorally, CCI mice showed pain hypersensitivity and a conditioned place-aversion (CPA) at a low heroin dose that supported conditioned place-preference (CPP) in naïve controls. Null mutations of Homer1a, Homer1, and Homer2, as well as transgenic disruption of mGluR5-Homer interactions, either attenuated or completely blocked low-dose heroin CPP, and none of the CCI mutant strains exhibited heroin-induced CPA. However, heroin CPP did not depend upon full Homer1c expression within the nucleus accumbens (NAC), as CPP occurred in controls infused locally with small hairpin RNA-Homer1c, although intra-NAC and/or intrathecal cDNA-Homer1c, -Homer1a, and -Homer2b infusions (to best mimic CCI's effects) were sufficient to blunt heroin CPP in uninjured mice. However, arguing against a simple role for CCI-induced increases in either spinal or NAC Homer expression for heroin CPA, cDNA infusion of our various cDNA constructs either did not affect (intrathecal) or attenuated (NAC) heroin CPA. Together, these data implicate increases in glutamate receptor/Homer/kinase activity within limbic structures, perhaps outside the NAC, as possibly critical for switching the incentive motivational properties of heroin following nerve injury, which has relevance for opioid psychopharmacology in individuals suffering from neuropathic pain.
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Affiliation(s)
- Ilona Obara
- Department of Psychology, Neuroscience Research Institute, University of California at Santa Barbara Santa Barbara, CA, USA ; School of Medicine, Pharmacy and Health, Queen's Campus, University of Durham Stockton on Tees, UK
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69
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Matosin N, Newell KA. Metabotropic glutamate receptor 5 in the pathology and treatment of schizophrenia. Neurosci Biobehav Rev 2012; 37:256-68. [PMID: 23253944 DOI: 10.1016/j.neubiorev.2012.12.005] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Revised: 10/27/2012] [Accepted: 12/09/2012] [Indexed: 02/07/2023]
Abstract
Metabotropic glutamate receptor 5 (mGluR5) potentiates the NMDA receptor (NMDAR) in brain regions implicated in schizophrenia, making it a viable therapeutic target for the treatment of this disorder. mGluR5 positive allosteric modulators may represent a valuable novel strategy for schizophrenia treatment, given the favourable profile of effects in preclinical paradigms. However it remains unclear whether mGluR5 also plays a causal or epiphenomenal role in NMDAR dysfunction in schizophrenia. Animal and cellular data suggest involvement of mGluR5, whilst post-mortem human studies remain inconclusive. This review will explore the molecular, animal and human data to support and refute the involvement of mGluR5 in the pathology of schizophrenia. Furthermore, this review will discuss the potential of mGluR5 modulators in the therapy of schizophrenia as well as aspects of mGluR5 that require further characterisation.
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Affiliation(s)
- Natalie Matosin
- Centre for Translational Neuroscience, Illawarra Health and Medical Research Institute, School of Health Sciences, University of Wollongong, NSW 2522, Australia
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70
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Piers TM, Kim DH, Kim BC, Regan P, Whitcomb DJ, Cho K. Translational Concepts of mGluR5 in Synaptic Diseases of the Brain. Front Pharmacol 2012. [PMID: 23205012 PMCID: PMC3506921 DOI: 10.3389/fphar.2012.00199] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The G-protein coupled receptor family of glutamate receptors, termed metabotropic glutamate receptors (mGluRs), are implicated in numerous cellular mechanisms ranging from neural development to the processing of cognitive, sensory, and motor information. Over the last decade, multiple mGluR-related signal cascades have been identified at excitatory synapses, indicating their potential roles in various forms of synaptic function and dysfunction. This review highlights recent studies investigating mGluR5, a subtype of group I mGluRs, and its association with a number of developmental, psychiatric, and senile synaptic disorders with respect to associated synaptic proteins, with an emphasis on translational pre-clinical studies targeting mGluR5 in a range of synaptic diseases of the brain.
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Affiliation(s)
- Thomas M Piers
- School of Clinical Sciences, Faculty of Medicine and Dentistry, University of Bristol Bristol, UK
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Affiliation(s)
- Jelena Radulovic
- Department of Psychiatry and Behavioral Sciences, The Asher Center for Study and Treatment of Depressive Disorders, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
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