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Kambali M, Li Y, Unichenko P, Feria Pliego JA, Yadav R, Liu J, McGuinness P, Cobb JG, Wang M, Nagarajan R, Lyu J, Vongsouthi V, Jackson CJ, Engin E, Coyle JT, Shin J, Hodgson NW, Hensch TK, Talkowski ME, Homanics GE, Bolshakov VY, Henneberger C, Rudolph U. An increased copy number of glycine decarboxylase (GLDC) associated with psychosis reduces extracellular glycine and impairs NMDA receptor function. Mol Psychiatry 2024:10.1038/s41380-024-02711-5. [PMID: 39210012 DOI: 10.1038/s41380-024-02711-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Revised: 08/15/2024] [Accepted: 08/21/2024] [Indexed: 09/04/2024]
Abstract
Glycine is an obligatory co-agonist at excitatory NMDA receptors in the brain, especially in the dentate gyrus, which has been postulated to be crucial for the development of psychotic associations and memories with psychotic content. Drugs modulating glycine levels are in clinical development for improving cognition in schizophrenia. However, the functional relevance of the regulation of glycine metabolism by endogenous enzymes is unclear. Using a chromosome-engineered allelic series in mice, we report that a triplication of the gene encoding the glycine-catabolizing enzyme glycine decarboxylase (GLDC) - as found on a small supernumerary marker chromosome in patients with psychosis - reduces extracellular glycine levels as determined by optical fluorescence resonance energy transfer (FRET) in dentate gyrus (DG) and suppresses long-term potentiation (LTP) in mPP-DG synapses but not in CA3-CA1 synapses, reduces the activity of biochemical pathways implicated in schizophrenia and mitochondrial bioenergetics, and displays deficits in schizophrenia-like behaviors which are in part known to be dependent on the activity of the dentate gyrus, e.g., prepulse inhibition, startle habituation, latent inhibition, working memory, sociability and social preference. Our results demonstrate that Gldc negatively regulates long-term synaptic plasticity in the dentate gyrus in mice, suggesting that an increase in GLDC copy number possibly contributes to the development of psychosis in humans.
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Affiliation(s)
- Maltesh Kambali
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Yan Li
- Cellular Neurobiology Laboratory, McLean Hospital Belmont, Belmont, MA, USA
- Deparment of Psychiatry, Harvard Medical School, Boston, MA, USA
| | - Petr Unichenko
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | | | - Rachita Yadav
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Jing Liu
- Deparment of Psychiatry, Harvard Medical School, Boston, MA, USA
- Laboratory of Genetic Neuropharmacology, McLean Hospital, Belmont, MA, USA
| | - Patrick McGuinness
- Deparment of Psychiatry, Harvard Medical School, Boston, MA, USA
- Laboratory of Genetic Neuropharmacology, McLean Hospital, Belmont, MA, USA
| | - Johanna G Cobb
- Deparment of Psychiatry, Harvard Medical School, Boston, MA, USA
- Laboratory of Genetic Neuropharmacology, McLean Hospital, Belmont, MA, USA
| | - Muxiao Wang
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois Urbana-Champaign, Urbana, IL, USA
- Neuroscience Program, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Rajasekar Nagarajan
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Jinrui Lyu
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois Urbana-Champaign, Urbana, IL, USA
- Neuroscience Program, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Vanessa Vongsouthi
- Research School of Chemistry, Australian National University, Canberra, ACT, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Australian National University, Canberra, ACT, 2601, Australia
| | - Colin J Jackson
- Research School of Chemistry, Australian National University, Canberra, ACT, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Australian National University, Canberra, ACT, 2601, Australia
| | - Elif Engin
- Deparment of Psychiatry, Harvard Medical School, Boston, MA, USA
- Laboratory of Genetic Neuropharmacology, McLean Hospital, Belmont, MA, USA
| | - Joseph T Coyle
- Deparment of Psychiatry, Harvard Medical School, Boston, MA, USA
| | - Jaeweon Shin
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Nathaniel W Hodgson
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA
- Center for Brain Science, Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
| | - Takao K Hensch
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA
- Center for Brain Science, Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
| | - Michael E Talkowski
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Gregg E Homanics
- Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Vadim Y Bolshakov
- Cellular Neurobiology Laboratory, McLean Hospital Belmont, Belmont, MA, USA
- Deparment of Psychiatry, Harvard Medical School, Boston, MA, USA
| | - Christian Henneberger
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Uwe Rudolph
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois Urbana-Champaign, Urbana, IL, USA.
- Deparment of Psychiatry, Harvard Medical School, Boston, MA, USA.
- Laboratory of Genetic Neuropharmacology, McLean Hospital, Belmont, MA, USA.
- Neuroscience Program, University of Illinois Urbana-Champaign, Urbana, IL, USA.
- Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Champaign, IL, USA.
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Brown SE, Wang Z(Z, Newman EL, Engin E, Berretta S, Balu DT, Folorunso OO. Serine racemase deletion alters adolescent social behavior and whole-brain cFos activation. Front Psychiatry 2024; 15:1365231. [PMID: 38979499 PMCID: PMC11228300 DOI: 10.3389/fpsyt.2024.1365231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Accepted: 05/06/2024] [Indexed: 07/10/2024] Open
Abstract
Background Neurodevelopmental disorders (NDDs) can cause debilitating impairments in social cognition and aberrant functional connectivity in large-scale brain networks, leading to social isolation and diminished everyday functioning. To facilitate the treatment of social impairments, animal models of NDDs that link N- methyl-D-aspartate receptor (NMDAR) hypofunction to social deficits in adulthood have been used. However, understanding the etiology of social impairments in NDDs requires investigating social changes during sensitive windows during development. Methods We examine social behavior during adolescence using a translational mouse model of NMDAR hypofunction (SR-/-) caused by knocking out serine racemase (SR), the enzyme needed to make D-serine, a key NMDAR coagonist. Species-typical social interactions are maintained through brain-wide neural activation patterns; therefore, we employed whole-brain cFos activity mapping to examine network-level connectivity changes caused by SR deletion. Results In adolescent SR-/- mice, we observed disinhibited social behavior toward a novel conspecific and rapid social habituation toward familiar social partners. SR-/- mice also spent more time in the open arm of the elevated plus maze which classically points to an anxiolytic behavioral phenotype. These behavioral findings point to a generalized reduction in anxiety-like behavior in both social and non-social contexts in SR-/- mice; importantly, these findings were not associated with diminished working memory. Inter-regional patterns of cFos activation revealed greater connectivity and network density in SR-/- mice compared to controls. Discussion These results suggest that NMDAR hypofunction - a potential biomarker for NDDs - can lead to generalized behavioral disinhibition in adolescence, potentially arising from disrupted communication between and within salience and default mode networks.
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Affiliation(s)
- Stephanie E. Brown
- Division of Basic Neuroscience, Translational Psychiatry Laboratory, McLean Hospital, Belmont, MA, United States
| | - Ziyi (Zephyr) Wang
- Division of Basic Neuroscience, Stress Neurobiology Laboratory, McLean Hospital, Belmont, MA, United States
| | - Emily L. Newman
- Department of Psychiatry, Harvard Medical School, Boston, MA, United States
- Division of Depression and Anxiety Disorders, Neurobiology of Fear Laboratory, McLean Hospital, Belmont, MA, United States
| | - Elif Engin
- Division of Basic Neuroscience, Stress Neurobiology Laboratory, McLean Hospital, Belmont, MA, United States
- Department of Psychiatry, Harvard Medical School, Boston, MA, United States
| | - Sabina Berretta
- Department of Psychiatry, Harvard Medical School, Boston, MA, United States
- Division of Basic Neuroscience, Translational Neuroscience Laboratory, McLean Hospital, Belmont, MA, United States
| | - Darrick T. Balu
- Division of Basic Neuroscience, Translational Psychiatry Laboratory, McLean Hospital, Belmont, MA, United States
- Department of Psychiatry, Harvard Medical School, Boston, MA, United States
| | - Oluwarotimi O. Folorunso
- Division of Basic Neuroscience, Translational Psychiatry Laboratory, McLean Hospital, Belmont, MA, United States
- Department of Psychiatry, Harvard Medical School, Boston, MA, United States
- Division of Basic Neuroscience, Translational Neuroscience Laboratory, McLean Hospital, Belmont, MA, United States
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3
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Arizanovska D, Emodogo JA, Lally AP, Palavicino-Maggio CB, Liebl DJ, Folorunso OO. Cross species review of the physiological role of D-serine in translationally relevant behaviors. Amino Acids 2023; 55:1501-1517. [PMID: 37833512 PMCID: PMC10689556 DOI: 10.1007/s00726-023-03338-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 09/19/2023] [Indexed: 10/15/2023]
Abstract
Bridging the gap between preclinical models of neurological and psychiatric disorders with their human manifestations is necessary to understand their underlying mechanisms, identify biomarkers, and develop novel therapeutics. Cognitive and social impairments underlie multiple neuropsychiatric and neurological disorders and are often comorbid with sleep disturbances, which can exacerbate poor outcomes. Importantly, many symptoms are conserved between vertebrates and invertebrates, although they may have subtle differences. Therefore, it is essential to determine the molecular mechanisms underlying these behaviors across different species and their translatability to humans. Genome-wide association studies have indicated an association between glutamatergic gene variants and both the risk and frequency of psychiatric disorders such as schizophrenia, bipolar disorder, and autism spectrum disorder. For example, changes in glutamatergic neurotransmission, such as glutamate receptor subtype N-methyl-D-aspartate receptor (NMDAR) hypofunction, have been shown to contribute to the pathophysiology of schizophrenia. Furthermore, in neurological disorders, such as traumatic brain injury and Alzheimer's disease, hyperactivation of NMDARs leads to synaptic damage. In addition to glutamate binding, NMDARs require the binding of a co-agonist D-serine or glycine to the GluN1 subunit to open. D-serine, which is racemized from L-serine by the neuronal enzyme serine racemase (SRR), and both SRR and D-serine are enriched in cortico-limbic brain regions. D-serine is critical for complex behaviors, such as cognition and social behavior, where dysregulation of its synthesis and release has been implicated in many pathological conditions. In this review, we explore the role of D-serine in behaviors that are translationally relevant to multiple psychiatric and neurological disorders in different models across species.
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Affiliation(s)
- Dena Arizanovska
- The Miami Project to Cure Paralysis, Department of Neurosurgery, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Jada A Emodogo
- Translational Psychiatry Laboratory, McLean Hospital, Belmont, MA, USA
| | - Anna P Lally
- Translational Neuroscience Laboratory, McLean Hospital, Belmont, MA, USA
| | - Caroline B Palavicino-Maggio
- Department of Psychiatry, Harvard Medical School, Boston, MA, USA
- Neurobiological Mechanisms of Aggression Laboratory, McLean Hospital, Belmont, MA, USA
| | - Daniel J Liebl
- The Miami Project to Cure Paralysis, Department of Neurosurgery, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Oluwarotimi O Folorunso
- Department of Psychiatry, Harvard Medical School, Boston, MA, USA.
- Translational Psychiatry Laboratory, McLean Hospital, Belmont, MA, USA.
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4
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Zhang YM, Qi YB, Gao YN, Chen WG, Zhou T, Zang Y, Li J. Astrocyte metabolism and signaling pathways in the CNS. Front Neurosci 2023; 17:1217451. [PMID: 37732313 PMCID: PMC10507181 DOI: 10.3389/fnins.2023.1217451] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 08/18/2023] [Indexed: 09/22/2023] Open
Abstract
Astrocytes comprise half of the cells in the central nervous system and play a critical role in maintaining metabolic homeostasis. Metabolic dysfunction in astrocytes has been indicated as the primary cause of neurological diseases, such as depression, Alzheimer's disease, and epilepsy. Although the metabolic functionalities of astrocytes are well known, their relationship to neurological disorders is poorly understood. The ways in which astrocytes regulate the metabolism of glucose, amino acids, and lipids have all been implicated in neurological diseases. Metabolism in astrocytes has also exhibited a significant influence on neuron functionality and the brain's neuro-network. In this review, we focused on metabolic processes present in astrocytes, most notably the glucose metabolic pathway, the fatty acid metabolic pathway, and the amino-acid metabolic pathway. For glucose metabolism, we focused on the glycolysis pathway, pentose-phosphate pathway, and oxidative phosphorylation pathway. In fatty acid metabolism, we followed fatty acid oxidation, ketone body metabolism, and sphingolipid metabolism. For amino acid metabolism, we summarized neurotransmitter metabolism and the serine and kynurenine metabolic pathways. This review will provide an overview of functional changes in astrocyte metabolism and provide an overall perspective of current treatment and therapy for neurological disorders.
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Affiliation(s)
- Yong-mei Zhang
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, Zhejiang, China
- National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Ying-bei Qi
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, Zhejiang, China
- National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Ya-nan Gao
- National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- Institute of Pharmaceutical Sciences, China Pharmaceutical University, Nanjing, Jiangsu, China
| | - Wen-gang Chen
- National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- Institute of Pharmaceutical Sciences, China Pharmaceutical University, Nanjing, Jiangsu, China
| | - Ting Zhou
- National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yi Zang
- National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jia Li
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, Zhejiang, China
- National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
- Institute of Pharmaceutical Sciences, China Pharmaceutical University, Nanjing, Jiangsu, China
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5
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Nicoletti F, Di Menna L, Iacovelli L, Orlando R, Zuena AR, Conn PJ, Dogra S, Joffe ME. GPCR interactions involving metabotropic glutamate receptors and their relevance to the pathophysiology and treatment of CNS disorders. Neuropharmacology 2023; 235:109569. [PMID: 37142158 DOI: 10.1016/j.neuropharm.2023.109569] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 04/18/2023] [Accepted: 05/02/2023] [Indexed: 05/06/2023]
Abstract
Cellular responses to metabotropic glutamate (mGlu) receptor activation are shaped by mechanisms of receptor-receptor interaction. mGlu receptor subtypes form homodimers, intra- or inter-group heterodimers, and heteromeric complexes with other G protein-coupled receptors (GPCRs). In addition, mGlu receptors may functionally interact with other receptors through the βγ subunits released from G proteins in response to receptor activation or other mechanisms. Here, we discuss the interactions between (i) mGlu1 and GABAB receptors in cerebellar Purkinje cells; (ii) mGlu2 and 5-HT2Aserotonergic receptors in the prefrontal cortex; (iii) mGlu5 and A2A receptors or mGlu5 and D1 dopamine receptors in medium spiny projection neurons of the indirect and direct pathways of the basal ganglia motor circuit; (iv) mGlu5 and A2A receptors in relation to the pathophysiology of Alzheimer's disease; and (v) mGlu7 and A1 adenosine or α- or β1 adrenergic receptors. In addition, we describe in detail a novel form of non-heterodimeric interaction between mGlu3 and mGlu5 receptors, which appears to be critically involved in mechanisms of activity-dependent synaptic plasticity in the prefrontal cortex and hippocampus. Finally, we highlight the potential implication of these interactions in the pathophysiology and treatment of cerebellar disorders, schizophrenia, Alzheimer's disease, Parkinson's disease, l-DOPA-induced dyskinesias, stress-related disorders, and cognitive dysfunctions.
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Affiliation(s)
- Ferdinando Nicoletti
- Department of Physiology and Pharmacology, Sapienza University of Rome, Italy; IRCCS Neuromed, Pozzilli, Italy.
| | | | - Luisa Iacovelli
- Department of Physiology and Pharmacology, Sapienza University of Rome, Italy
| | - Rosamaria Orlando
- Department of Physiology and Pharmacology, Sapienza University of Rome, Italy; IRCCS Neuromed, Pozzilli, Italy
| | - Anna Rita Zuena
- Department of Physiology and Pharmacology, Sapienza University of Rome, Italy
| | - P Jeffrey Conn
- Department of Pharmacology, Italy; Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN, 37232, USA
| | - Shalini Dogra
- Department of Pharmacology, Italy; Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN, 37232, USA
| | - Max E Joffe
- Translational Neuroscience Program, Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, 15219, USA
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6
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Brown J, Grayson B, Neill JC, Harte M, Wall MJ, Ngomba RT. Oscillatory Deficits in the Sub-Chronic PCP Rat Model for Schizophrenia Are Reversed by mGlu5 Receptor-Positive Allosteric Modulators VU0409551 and VU0360172. Cells 2023; 12:cells12060919. [PMID: 36980260 PMCID: PMC10047164 DOI: 10.3390/cells12060919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/13/2023] [Accepted: 03/15/2023] [Indexed: 03/19/2023] Open
Abstract
The cognitive deficits of schizophrenia are linked to imbalanced excitatory and inhibitory signalling in the prefrontal cortex (PFC), disrupting gamma oscillations. We previously demonstrated that two mGlu5 receptor-positive allosteric modulators (PAMs), VU0409551 and VU0360172, restore cognitive deficits in the sub-chronic PCP (scPCP) rodent model for schizophrenia via distinct changes in PFC intracellular signalling molecules. Here, we have assessed ex vivo gamma oscillatory activity in PFC slices from scPCP rats and investigated the effects of VU0409551 and VU0360172 upon oscillatory power. mGlu5 receptor, protein kinase C (PKC), and phospholipase C (PLC) inhibition were also used to examine ‘modulation bias’ in PAM activity. The amplitude and area power of gamma oscillations were significantly diminished in the scPCP model. Slice incubation with either VU0409551 or VU0360172 rescued scPCP-induced oscillatory deficits in a concentration-dependent manner. MTEP blocked the PAM-induced restoration of oscillatory power, confirming the requirement of mGlu5 receptor modulation. Whilst PLC inhibition prevented the power increase mediated by both PAMs, PKC inhibition diminished the effects of VU0360172 but not VU0409551. This aligns with previous reports that VU0409551 exhibits preferential activation of the phosphatidylinositol-3-kinase (PI3K) signalling pathway over the PKC cascade. Restoration of the excitatory/inhibitory signalling balance and gamma oscillations may therefore underlie the mGluR5 PAM-mediated correction of scPCP-induced cognitive deficits.
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Affiliation(s)
- Jessica Brown
- Division of Pharmacy & Optometry, University of Manchester, Manchester M13 9PT, UK
| | - Ben Grayson
- Division of Pharmacy & Optometry, University of Manchester, Manchester M13 9PT, UK
| | - Joanna C. Neill
- Division of Pharmacy & Optometry, University of Manchester, Manchester M13 9PT, UK
| | - Michael Harte
- Division of Pharmacy & Optometry, University of Manchester, Manchester M13 9PT, UK
- Correspondence: (M.H.); (M.J.W.); (R.T.N.); Tel.: +44-(0)161-2752328 (M.H.); +44-(0)247-6573772 (M.J.W.); +44-(0)152-2837392 (R.T.N.)
| | - Mark J. Wall
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK
- Correspondence: (M.H.); (M.J.W.); (R.T.N.); Tel.: +44-(0)161-2752328 (M.H.); +44-(0)247-6573772 (M.J.W.); +44-(0)152-2837392 (R.T.N.)
| | - Richard T. Ngomba
- School of Pharmacy, University of Lincoln, Lincoln LN6 7DL, UK
- Correspondence: (M.H.); (M.J.W.); (R.T.N.); Tel.: +44-(0)161-2752328 (M.H.); +44-(0)247-6573772 (M.J.W.); +44-(0)152-2837392 (R.T.N.)
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7
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Witkin JM, Pandey KP, Smith JL. Clinical investigations of compounds targeting metabotropic glutamate receptors. Pharmacol Biochem Behav 2022; 219:173446. [PMID: 35987339 DOI: 10.1016/j.pbb.2022.173446] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 06/22/2022] [Accepted: 08/08/2022] [Indexed: 11/15/2022]
Abstract
Pharmacological modulation of glutamate has long been considered to be of immense therapeutic utility. The metabotropic glutamate receptors (mGluRs) are potential targets for safely altering glutamate-driven excitation. Data support the potential therapeutic use of mGluR modulators in the treatment of anxiety, depression, schizophrenia, and other psychiatric disorders, pain, epilepsy, as well as neurodegenerative and neurodevelopmental disorders. For each of the three mGluR groups, compounds have been constructed that produce either potentiation or functional blockade. PET ligands for mGlu5Rs have been studied in a range of patient populations and several mGlu5R antagonists have been tested for potential efficacy in patients including mavoglurant, diploglurant, basimglurant, GET 73, and ADX10059. Efficacy with mGlu5R antagonists has been reported in trials with patients with gastroesophageal reflux disease; data from patients with Parkinson's disease or Fragile X syndrome have not been as robust as hoped. Fenobam was approved for use as an anxiolytic prior to its recognition as an mGlu5R antagonist. mGlu2/3R agonists (pomaglumated methionil) and mGlu2R agonists (JNJ-40411813, AZD 8529, and LY2979165) have been studied in patients with schizophrenia with promising but mixed results. Antagonists of mGlu2/3Rs (decoglurant and TS-161) have been studied in depression where TS-161 has advanced into a planned Phase 2 study in treatment-resistant depression. The Group III mGluRs are the least developed of the mGluR receptor targets. The mGlu4R potentiator, foliglurax, did not meet its primary endpoint in patients with Parkinson's disease. Ongoing efforts to develop mGluR-targeted compounds continue to promise these glutamate modulators as medicines for psychiatric and neurological disorders.
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Affiliation(s)
- Jeffrey M Witkin
- Laboratory of Antiepileptic Drug Discovery, Ascension St. Vincent, Indianapolis, IN, USA; Department of Chemistry & Biochemistry, Milwaukee Institute of Drug Discovery, University of Wisconsin-Milwaukee, Milwaukee, WI, USA; RespireRx Pharmaceuticals Inc, Glen Rock, NJ, USA.
| | - Kamal P Pandey
- Department of Chemistry & Biochemistry, Milwaukee Institute of Drug Discovery, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Jodi L Smith
- Laboratory of Antiepileptic Drug Discovery, Ascension St. Vincent, Indianapolis, IN, USA
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8
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Dogra S, Conn PJ. Metabotropic Glutamate Receptors As Emerging Targets for the Treatment of Schizophrenia. Mol Pharmacol 2022; 101:275-285. [PMID: 35246479 PMCID: PMC9092465 DOI: 10.1124/molpharm.121.000460] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 02/22/2022] [Indexed: 11/22/2022] Open
Abstract
Accumulating evidence of glutamatergic abnormalities in the brains of schizophrenia patients has led to efforts to target various components of glutamatergic signaling as potential new approaches for schizophrenia. Exciting research suggests that metabotropic glutamate (mGlu) receptors could provide a fundamentally new approach for better symptomatic relief in patients with schizophrenia. In preclinical studies, the mGlu5 receptor positive allosteric modulators (PAMs) show efficacy in animal models relevant for all symptom domains in schizophrenia. Interestingly, biased pure mGlu5 receptor PAMs that do not potentiate coupling of mGlu5 receptors to N-methyl-D-aspartate (NMDA) receptors lack neurotoxic effects associated with mGlu5 PAMs that enhance coupling to NMDA receptors or have allosteric agonist activity. This provides a better therapeutic profile for treating schizophrenia-like symptoms. Additionally, the mGlu1 receptor PAMs modulate dopamine release in the striatum, which may contribute to their antipsychotic-like effects. Besides group I mGlu (mGlu1 and mGlu5) receptors, agonists of mGlu2/3 receptors also induce robust antipsychotic-like and procognitive effects in rodents and may be effective in treating symptoms of schizophrenia in a selective group of patients. Additionally, mGlu2/4 receptor heterodimers modulate glutamatergic neurotransmission in the prefrontal cortex at selective synapses activated in schizophrenia and therefore hold potential as novel antipsychotics. Excitingly, the mGlu3 receptor activation can enhance cognition in rodents, suggesting that mGlu3 receptor agonist/PAM could provide a novel approach for the treatment of cognitive deficits in schizophrenia. Collectively, the development of mGlu receptor-specific ligands may provide an alternative approach to meet the clinical need for safer and more efficacious therapeutics for schizophrenia. SIGNIFICANCE STATEMENT: The currently available antipsychotic medications do not show significant efficacy for treating negative symptoms and cognitive deficits in schizophrenia. Emerging preclinical and clinical literature suggests that pharmacological targeting of metabotropic glutamate receptors could potentially provide an alternative approach for designing safer and more efficacious therapeutics for treating schizophrenia.
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Affiliation(s)
- Shalini Dogra
- Department of Pharmacology and Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee
| | - P Jeffrey Conn
- Department of Pharmacology and Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee
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9
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Brown J, Iacovelli L, Di Cicco G, Grayson B, Rimmer L, Fletcher J, Neill JC, Wall MJ, Ngomba RT, Harte M. The comparative effects of mGlu5 receptor positive allosteric modulators VU0409551 and VU0360172 on cognitive deficits and signalling in the sub-chronic PCP rat model for schizophrenia. Neuropharmacology 2022; 208:108982. [DOI: 10.1016/j.neuropharm.2022.108982] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 01/28/2022] [Accepted: 02/01/2022] [Indexed: 02/08/2023]
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10
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Brown RW, Varnum CG, Wills LJ, Peeters LD, Gass JT. Modulation of mGlu5 improves sensorimotor gating deficits in rats neonatally treated with quinpirole through changes in dopamine D2 signaling. Pharmacol Biochem Behav 2021; 211:173292. [PMID: 34710401 PMCID: PMC9176413 DOI: 10.1016/j.pbb.2021.173292] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 10/19/2021] [Accepted: 10/20/2021] [Indexed: 12/19/2022]
Abstract
This study analyzed whether the positive allosteric modulator of metabotropic glutamate receptor type 5 (mGlu5) 3-Cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl) benzamide (CDPPB) would alleviate deficits in prepulse inhibition (PPI) and affect dopamine (DA) D2 signaling in the dorsal striatum and prefrontal cortex (PFC) in the neonatal quinpirole (NQ) model of schizophrenia (SZ). Male and female Sprague-Dawley rats were neonatally treated with either saline (NS) or quinpirole HCL (1 mg/kg; NQ), a DAD2 receptor agonist, from postnatal days (P) 1-21. Rats were raised to P44 and behaviorally tested on PPI from P44-P48. Before each trial, rats were subcutaneous (sc) administered saline or CDPPB (10 mg/kg or 30 mg/kg). On P50, rats were given a spontaneous locomotor activity test after CDPPB or saline administration. On P51, the dorsal striatum and PFC were evaluated for both arrestin-2 (βA-2) and phospho-AKT protein levels. NQ-treated rats demonstrated a significant deficit in PPI, which was alleviated to control levels by the 30 mg/kg dose of CDPPB. There were no significant effects of CDPPB on locomotor activity. NQ treatment increased βA-2 and decreased phospho-AKT in both the dorsal striatum and PFC, consistent with an increase DAD2 signaling. The 30 mg/kg dose of CDPPB significantly reversed changes in βA-2 in the dorsal striatum and PFC and phospho-AKT in the PFC equivalent to controls. Both doses of CDPPB produced a decrease of phospho-AKT in the PFC compared to controls. This study revealed that a mGlu5 positive allosteric modulator was effective to alleviate PPI deficits and striatal DAD2 signaling in the NQ model of SZ.
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Affiliation(s)
- Russell W Brown
- Department of Biomedical Sciences James H. Quillen College of Medicine, East Tennessee State University Johnson City, TN 37614, United States of America.
| | - Christopher G Varnum
- Department of Biomedical Sciences James H. Quillen College of Medicine, East Tennessee State University Johnson City, TN 37614, United States of America
| | - Liza J Wills
- Department of Biomedical Sciences James H. Quillen College of Medicine, East Tennessee State University Johnson City, TN 37614, United States of America
| | - Loren D Peeters
- Department of Biomedical Sciences James H. Quillen College of Medicine, East Tennessee State University Johnson City, TN 37614, United States of America
| | - Justin T Gass
- Department of Biomedical Sciences James H. Quillen College of Medicine, East Tennessee State University Johnson City, TN 37614, United States of America
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11
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Costa BM, Kwapisz LC, Mehrkens B, Bledsoe DN, Vacca BN, Johnston TV, Razzaq R, Manickam D, Klein BG. A glutamate concentration-biased allosteric modulator potentiates NMDA-induced ion influx in neurons. Pharmacol Res Perspect 2021; 9:e00859. [PMID: 34476911 PMCID: PMC8413904 DOI: 10.1002/prp2.859] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Accepted: 08/14/2021] [Indexed: 11/11/2022] Open
Abstract
Precisely controlled synaptic glutamate concentration is essential for the normal function of the N-methyl D-aspartate (NMDA) receptors. Atypical fluctuations in synaptic glutamate homeostasis lead to aberrant NMDA receptor activity that results in the pathogenesis of neurological and psychiatric disorders. Therefore, glutamate concentration-dependent NMDA receptor modulators would be clinically useful agents with fewer on-target adverse effects. In the present study, we have characterized a novel compound (CNS4) that potentiates NMDA receptor currents based on glutamate concentration. This compound alters glutamate potency and exhibits no voltage-dependent effect. Patch-clamp electrophysiology recordings confirmed agonist concentration-dependent changes in maximum inducible currents. Dynamic Ca2+ and Na+ imaging assays using rat brain cortical, striatal and cerebellar neurons revealed CNS4 potentiated ion influx through native NMDA receptor activity. Overall, CNS4 is novel in chemical structure, mechanism of action and agonist concentration-biased allosteric modulatory effect. This compound or its future analogs will serve as useful candidates to develop drug-like compounds for the treatment of treatment-resistant schizophrenia and major depression disorders associated with hypoglutamatergic neurotransmission.
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Affiliation(s)
- Blaise M. Costa
- Center for One Health ResearchVirginia Maryland College of Veterinary MedicineVirginia TechBlacksburgVirginiaUSA
- Edward Via Virginia College of Osteopathic Medicine (VCOMBlacksburgVirginiaUSA
- School of NeuroscienceVirginia TechBlacksburgVirginiaUSA
| | - Lina Cortés Kwapisz
- Center for One Health ResearchVirginia Maryland College of Veterinary MedicineVirginia TechBlacksburgVirginiaUSA
| | - Brittney Mehrkens
- Center for One Health ResearchVirginia Maryland College of Veterinary MedicineVirginia TechBlacksburgVirginiaUSA
| | - Douglas N. Bledsoe
- Center for One Health ResearchVirginia Maryland College of Veterinary MedicineVirginia TechBlacksburgVirginiaUSA
- Present address:
Virginia Commonwealth UniversityRichmondVirginiaUSA
| | - Bryanna N. Vacca
- Center for One Health ResearchVirginia Maryland College of Veterinary MedicineVirginia TechBlacksburgVirginiaUSA
- Present address:
University of North CarolinaChapel HillNorth CarolinaUSA
| | - Tullia V. Johnston
- Center for One Health ResearchVirginia Maryland College of Veterinary MedicineVirginia TechBlacksburgVirginiaUSA
| | - Rehan Razzaq
- Edward Via Virginia College of Osteopathic Medicine (VCOMBlacksburgVirginiaUSA
| | | | - Bradley G. Klein
- Center for One Health ResearchVirginia Maryland College of Veterinary MedicineVirginia TechBlacksburgVirginiaUSA
- School of NeuroscienceVirginia TechBlacksburgVirginiaUSA
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12
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Dogra S, Stansley BJ, Xiang Z, Qian W, Gogliotti RG, Nicoletti F, Lindsley CW, Niswender CM, Joffe ME, Conn PJ. Activating mGlu 3 Metabotropic Glutamate Receptors Rescues Schizophrenia-like Cognitive Deficits Through Metaplastic Adaptations Within the Hippocampus. Biol Psychiatry 2021; 90:385-398. [PMID: 33965197 PMCID: PMC8403106 DOI: 10.1016/j.biopsych.2021.02.970] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 02/08/2021] [Accepted: 02/08/2021] [Indexed: 12/26/2022]
Abstract
BACKGROUND Polymorphisms in GRM3, the gene encoding the mGlu3 metabotropic glutamate receptor, are associated with impaired cognition and neuropsychiatric disorders such as schizophrenia. Limited availability of selective genetic and molecular tools has hindered progress in developing a clear understanding of the mechanisms through which mGlu3 receptors regulate synaptic plasticity and cognition. METHODS We examined associative learning in mice with trace fear conditioning, a hippocampal-dependent learning task disrupted in patients with schizophrenia. Underlying cellular mechanisms were assessed using ex vivo hippocampal slice preparations with selective pharmacological tools and selective genetic deletion of mGlu3 receptor expression in specific neuronal subpopulations. RESULTS mGlu3 receptor activation enhanced trace fear conditioning and reversed deficits induced by subchronic phencyclidine. Mechanistic studies revealed that mGlu3 receptor activation induced metaplastic changes, biasing afferent stimulation to induce long-term potentiation through an mGlu5 receptor-dependent, endocannabinoid-mediated, disinhibitory mechanism. Selective genetic deletion of either mGlu3 or mGlu5 from hippocampal pyramidal cells eliminated effects of mGlu3 activation, revealing a novel mechanism by which mGlu3 and mGlu5 interact to enhance cognitive function. CONCLUSIONS These data demonstrate that activation of mGlu3 receptors in hippocampal pyramidal cells enhances hippocampal-dependent cognition in control and impaired mice by inducing a novel form of metaplasticity to regulate circuit function, providing a clear mechanism through which genetic variation in GRM3 can contribute to cognitive deficits. Developing approaches to positively modulate mGlu3 receptor function represents an encouraging new avenue for treating cognitive disruption in schizophrenia and other psychiatric diseases.
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Affiliation(s)
- Shalini Dogra
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA,Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA
| | - Branden J. Stansley
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA,Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA
| | - Zixiu Xiang
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA,Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA
| | - Weilun Qian
- Vanderbilt University, Nashville, TN 37232, USA
| | - Rocco G. Gogliotti
- Molecular Pharmacology and Neuroscience Department, Loyola University Chicago, Maywood, IL, 60153, USA
| | - Ferdinando Nicoletti
- IRCCS Neuromed, Pozzilli, Italy,Department of Physiology and Pharmacology, University Sapienza of Roma, Roma, Italy
| | - Craig W. Lindsley
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA,Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA,Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, TN, 37232, USA,Department of Chemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - Colleen M. Niswender
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA,Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA,Vanderbilt Kennedy Center, Vanderbilt University, Nashville, TN 37232, USA
| | - Max E. Joffe
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA,Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA,Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, TN, 37232, USA,Correspondence to: Max E. Joffe, Ph.D., Research Instructor, Department of Pharmacology, Vanderbilt University, 12475E MRB4, Nashville, TN 37232-0697, Tel. (615) 322-6730, Fax. (615) 343-3088, , Twitter: @mejoffe; P. Jeffrey Conn, Ph.D., Lee E. Limbird Professor of Pharmacology, Warren Center for Neuroscience Drug Discovery, Vanderbilt University, 1205 Light Hall, Nashville, TN 37232-0697, Tel. (615) 936-2478, Fax. (615) 343-3088,
| | - P. Jeffrey Conn
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA,Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA,Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, TN, 37232, USA,Vanderbilt Kennedy Center, Vanderbilt University, Nashville, TN 37232, USA,Correspondence to: Max E. Joffe, Ph.D., Research Instructor, Department of Pharmacology, Vanderbilt University, 12475E MRB4, Nashville, TN 37232-0697, Tel. (615) 322-6730, Fax. (615) 343-3088, , Twitter: @mejoffe; P. Jeffrey Conn, Ph.D., Lee E. Limbird Professor of Pharmacology, Warren Center for Neuroscience Drug Discovery, Vanderbilt University, 1205 Light Hall, Nashville, TN 37232-0697, Tel. (615) 936-2478, Fax. (615) 343-3088,
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13
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Zhang Z, Wang L, Liu Y, Luan Y, Zhu K, Tian Y, Liu Y, Zheng X. Activation of type 4 metabotropic glutamate receptor attenuates oxygen and glucose deprivation-induced apoptosis in human neural stem cells via inhibition of ASK1-p38 signaling pathway. Brain Res 2021; 1767:147561. [PMID: 34133989 DOI: 10.1016/j.brainres.2021.147561] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 05/19/2021] [Accepted: 06/11/2021] [Indexed: 10/21/2022]
Abstract
Hypoxic ischemic brain injury (HIBI) has been one of the most severe central nervous system (CNS) diseases with high fatality and disability rate. Neural stem cells (NSCs) persist in the mammalian brain throughout life and NSCs-associated therapies might be a promising strategy for the HIBI treatment. In this study, we identified that type 4 metabotropic glutamate receptor (mGluR4) was expressed in cultured human NSCs (hNSCs) isolated from the human fetus cortex and further established the oxygen and glucose deprivation (OGD) model in hNSCs to study the role of mGluR4 in hypoxic and ischemic injury. The results indicated that mGluR4 activation by using VU0155041 (mGluR4-specific agonist) markedly attenuated the OGD-induced alterations in TUNEL staining, apoptosis rate, cleavages of pro-caspase-8, -9, -3, and Bcl-2/Bax expression balance. Furthermore, mGluR4 activation inhibited the ASK1/p38 signaling pathway. Asiatic acid, as a p38 MAPK activator, is capable of abolishing the neuroprotective effect of mGluR4, while both NQDI-1 (ASK-1 inhibitor) and SB203580 (p38 MAPK inhibitor) exerted similar effects to VU0155041 in the OGD-induced hNSC damage. In conclusion, this study indicates that mGluR4 activation protects hNSCs against the OGD-induced cell death via inhibiting the ASK1-p38 pathway. Activation of mGluR4 might be a promising strategy for enhancing NSCs survival in hypoxic and ischemic injury.
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Affiliation(s)
- Zhe Zhang
- Department of Stomatology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, China; Institute of Neurobiology, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, China
| | - Li Wang
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of Xi'an Medical University, Xi'an, Shaanxi 710077, China
| | - Yingfei Liu
- Institute of Neurobiology, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, China
| | - Yan Luan
- Institute of Neurobiology, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, China
| | - Kun Zhu
- Department of Neurology, Shaanxi Provincial People's Hospital, Xi'an, Shaanxi 710061, China
| | - Yumei Tian
- Department of Rehabilitation, Xi'an Mental Health Center, Xi'an, Shaanxi 710061, China
| | - Yong Liu
- Institute of Neurobiology, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, China.
| | - Xiaoyan Zheng
- Department of Hematology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, China.
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14
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Jami SA, Cameron S, Wong JM, Daly ER, McAllister AK, Gray JA. Increased excitation-inhibition balance and loss of GABAergic synapses in the serine racemase knockout model of NMDA receptor hypofunction. J Neurophysiol 2021; 126:11-27. [PMID: 34038186 DOI: 10.1152/jn.00661.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
There is substantial evidence that both N-methyl-D-aspartate receptor (NMDAR) hypofunction and dysfunction of GABAergic neurotransmission contribute to schizophrenia, though the relationship between these pathophysiological processes remains largely unknown. Although models using cell-type-specific genetic deletion of NMDARs have been informative, they display overly pronounced phenotypes extending beyond those of schizophrenia. Here, we used the serine racemase knockout (SRKO) mice, a model of reduced NMDAR activity rather than complete receptor elimination, to examine the link between NMDAR hypofunction and decreased GABAergic inhibition. The SRKO mice, in which there is a >90% reduction in the NMDAR coagonist d-serine, exhibit many of the neurochemical and behavioral abnormalities observed in schizophrenia. We found a significant reduction in inhibitory synapses onto CA1 pyramidal neurons in the SRKO mice. This reduction increases the excitation/inhibition balance resulting in enhanced synaptically driven neuronal excitability without changes in intrinsic excitability. Consistently, significant reductions in inhibitory synapse density in CA1 were observed by immunohistochemistry. We further show, using a single-neuron genetic deletion approach, that the loss of GABAergic synapses onto pyramidal neurons observed in the SRKO mice is driven in a cell-autonomous manner following the deletion of SR in individual CA1 pyramidal cells. These results support a model whereby NMDAR hypofunction in pyramidal cells disrupts GABAergic synapses leading to disrupted feedback inhibition and impaired neuronal synchrony.NEW & NOTEWORTHY Recently, disruption of excitation/inhibition (E/I) balance has become an area of considerable interest for psychiatric research. Here, we report a reduction in inhibition in the serine racemase knockout mouse model of schizophrenia that increases E/I balance and enhances synaptically driven neuronal excitability. This reduced inhibition was driven cell-autonomously in pyramidal cells lacking serine racemase, suggesting a novel mechanism for how chronic NMDA receptor hypofunction can disrupt information processing in schizophrenia.
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Affiliation(s)
- Shekib A Jami
- Center for Neuroscience, University of California, Davis, California
| | - Scott Cameron
- Center for Neuroscience, University of California, Davis, California
| | - Jonathan M Wong
- Center for Neuroscience, University of California, Davis, California
| | - Emily R Daly
- Center for Neuroscience, University of California, Davis, California
| | - A Kimberley McAllister
- Center for Neuroscience, University of California, Davis, California.,Department of Neurobiology, Physiology, and Behavior, University of California, Davis, California.,Department of Neurology, University of California, Davis, California
| | - John A Gray
- Center for Neuroscience, University of California, Davis, California.,Department of Neurology, University of California, Davis, California
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15
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Boczek T, Mackiewicz J, Sobolczyk M, Wawrzyniak J, Lisek M, Ferenc B, Guo F, Zylinska L. The Role of G Protein-Coupled Receptors (GPCRs) and Calcium Signaling in Schizophrenia. Focus on GPCRs Activated by Neurotransmitters and Chemokines. Cells 2021; 10:cells10051228. [PMID: 34067760 PMCID: PMC8155952 DOI: 10.3390/cells10051228] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/12/2021] [Accepted: 05/14/2021] [Indexed: 01/13/2023] Open
Abstract
Schizophrenia is a common debilitating disease characterized by continuous or relapsing episodes of psychosis. Although the molecular mechanisms underlying this psychiatric illness remain incompletely understood, a growing body of clinical, pharmacological, and genetic evidence suggests that G protein-coupled receptors (GPCRs) play a critical role in disease development, progression, and treatment. This pivotal role is further highlighted by the fact that GPCRs are the most common targets for antipsychotic drugs. The GPCRs activation evokes slow synaptic transmission through several downstream pathways, many of them engaging intracellular Ca2+ mobilization. Dysfunctions of the neurotransmitter systems involving the action of GPCRs in the frontal and limbic-related regions are likely to underly the complex picture that includes the whole spectrum of positive and negative schizophrenia symptoms. Therefore, the progress in our understanding of GPCRs function in the control of brain cognitive functions is expected to open new avenues for selective drug development. In this paper, we review and synthesize the recent data regarding the contribution of neurotransmitter-GPCRs signaling to schizophrenia symptomology.
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Affiliation(s)
- Tomasz Boczek
- Department of Molecular Neurochemistry, Faculty of Health Sciences, Medical University of Lodz, 92215 Lodz, Poland; (T.B.); (J.M.); (M.S.); (J.W.); (M.L.); (B.F.)
| | - Joanna Mackiewicz
- Department of Molecular Neurochemistry, Faculty of Health Sciences, Medical University of Lodz, 92215 Lodz, Poland; (T.B.); (J.M.); (M.S.); (J.W.); (M.L.); (B.F.)
| | - Marta Sobolczyk
- Department of Molecular Neurochemistry, Faculty of Health Sciences, Medical University of Lodz, 92215 Lodz, Poland; (T.B.); (J.M.); (M.S.); (J.W.); (M.L.); (B.F.)
| | - Julia Wawrzyniak
- Department of Molecular Neurochemistry, Faculty of Health Sciences, Medical University of Lodz, 92215 Lodz, Poland; (T.B.); (J.M.); (M.S.); (J.W.); (M.L.); (B.F.)
| | - Malwina Lisek
- Department of Molecular Neurochemistry, Faculty of Health Sciences, Medical University of Lodz, 92215 Lodz, Poland; (T.B.); (J.M.); (M.S.); (J.W.); (M.L.); (B.F.)
| | - Bozena Ferenc
- Department of Molecular Neurochemistry, Faculty of Health Sciences, Medical University of Lodz, 92215 Lodz, Poland; (T.B.); (J.M.); (M.S.); (J.W.); (M.L.); (B.F.)
| | - Feng Guo
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang 110122, China;
| | - Ludmila Zylinska
- Department of Molecular Neurochemistry, Faculty of Health Sciences, Medical University of Lodz, 92215 Lodz, Poland; (T.B.); (J.M.); (M.S.); (J.W.); (M.L.); (B.F.)
- Correspondence:
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16
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Folorunso OO, Harvey TL, Brown SE, Cruz C, Shahbo E, Ajjawi I, Balu DT. Forebrain expression of serine racemase during postnatal development. Neurochem Int 2021; 145:104990. [PMID: 33592203 PMCID: PMC8012237 DOI: 10.1016/j.neuint.2021.104990] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 01/25/2021] [Accepted: 02/10/2021] [Indexed: 12/23/2022]
Abstract
N-methyl-D-aspartate receptors (NMDARs) are important for synaptogenesis, synaptic maturation and refinement during the early postnatal weeks after birth. Defective synapse formation or refinement underlie cognitive and emotional abnormalities in various neurodevelopmental disorders (NDDs), including schizophrenia (Sz) and autism spectrum disorder (ASD). Serine racemase (SR) is a neuronal enzyme that produces D-serine, a co-agonist required for full NMDAR activation. NMDAR hypofunction as a result of genetic SR elimination and reduced synaptic availability of D-serine reduces neuronal dendritic arborization and spine density. In adult mouse brain, the expression of SR parallels that of NMDARs across forebrain regions including the striatum, amygdala, hippocampus, and medial prefrontal cortex (mPFC). However, there have yet to be studies providing a detailed characterization of the spatial and temporal expression of SR during early periods of synaptogenesis. Here, we examined the postnatal expression of SR in cortical and subcortical brain regions important for learning, memory and emotional regulation, during the first four weeks after birth. Using dual-antigen immunofluorescence, we demonstrate that the number of SR+ neurons steadily increases with postnatal age across the mPFC, amygdala, hippocampus and striatum. We also identified differences in the rate of SR protein induction both across and within brain regions. Analyzing existing human post-mortem brain in situ data, there was a similar developmental mRNA expression profile of SRR and GRIN1 (GluN1 subunit) from infancy through the first decade of life. Our findings further support a developmental role for D-serine mediated NMDAR activation regulating synaptogenesis and neural circuit refinement, which has important implications for the pathophysiology of Sz and other NDDs.
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Affiliation(s)
- Oluwarotimi O Folorunso
- Department of Psychiatry, Harvard Medical School, Boston, MA, 02115, United States; Translational Psychiatry Laboratory, McLean Hospital, Belmont, MA, 02478, United States
| | - Theresa L Harvey
- Translational Psychiatry Laboratory, McLean Hospital, Belmont, MA, 02478, United States
| | - Stephanie E Brown
- Translational Psychiatry Laboratory, McLean Hospital, Belmont, MA, 02478, United States
| | - Cristina Cruz
- Translational Psychiatry Laboratory, McLean Hospital, Belmont, MA, 02478, United States; Harvard University, Cambridge, MA, 02138, United States
| | - Ellie Shahbo
- Translational Psychiatry Laboratory, McLean Hospital, Belmont, MA, 02478, United States; Harvard University, Cambridge, MA, 02138, United States
| | - Ismail Ajjawi
- Translational Psychiatry Laboratory, McLean Hospital, Belmont, MA, 02478, United States; Harvard University, Cambridge, MA, 02138, United States
| | - Darrick T Balu
- Department of Psychiatry, Harvard Medical School, Boston, MA, 02115, United States; Translational Psychiatry Laboratory, McLean Hospital, Belmont, MA, 02478, United States.
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17
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Wu Q, Huang J, Wu R. Drugs Based on NMDAR Hypofunction Hypothesis in Schizophrenia. Front Neurosci 2021; 15:641047. [PMID: 33912003 PMCID: PMC8072017 DOI: 10.3389/fnins.2021.641047] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Accepted: 03/12/2021] [Indexed: 12/30/2022] Open
Abstract
Treatments for negative symptoms and cognitive dysfunction in schizophrenia remain issues that psychiatrists around the world are trying to solve. Their mechanisms may be associated with N-methyl-D-aspartate receptors (NMDARs). The NMDAR hypofunction hypothesis for schizophrenia was brought to the fore mainly based on the clinical effects of NMDAR antagonists and anti-NMDAR encephalitis pathology. Drugs targeted at augmenting NMDAR function in the brain seem to be promising in improving negative symptoms and cognitive dysfunction in patients with schizophrenia. In this review, we list NMDAR-targeted drugs and report on related clinical studies. We then summarize their effects on negative symptoms and cognitive dysfunction and analyze the unsatisfactory outcomes of these clinical studies according to the improved glutamate hypothesis that has been revealed in animal models. We aimed to provide perspectives for scientists who sought therapeutic strategies for negative symptoms and cognitive dysfunction in schizophrenia based on the NMDAR hypofunction hypothesis.
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Affiliation(s)
- Qiongqiong Wu
- Department of Psychiatry, National Clinical Research Center for Mental Disorders, The Second Xiangya Hospital of Central South University, Changsha, China
| | - Jing Huang
- Department of Psychiatry, National Clinical Research Center for Mental Disorders, The Second Xiangya Hospital of Central South University, Changsha, China
| | - Renrong Wu
- Department of Psychiatry, National Clinical Research Center for Mental Disorders, The Second Xiangya Hospital of Central South University, Changsha, China
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18
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Kryszkowski W, Boczek T. The G Protein-Coupled Glutamate Receptors as Novel Molecular Targets in Schizophrenia Treatment-A Narrative Review. J Clin Med 2021; 10:jcm10071475. [PMID: 33918323 PMCID: PMC8038150 DOI: 10.3390/jcm10071475] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 03/24/2021] [Accepted: 03/28/2021] [Indexed: 12/02/2022] Open
Abstract
Schizophrenia is a severe neuropsychiatric disease with an unknown etiology. The research into the neurobiology of this disease led to several models aimed at explaining the link between perturbations in brain function and the manifestation of psychotic symptoms. The glutamatergic hypothesis postulates that disrupted glutamate neurotransmission may mediate cognitive and psychosocial impairments by affecting the connections between the cortex and the thalamus. In this regard, the greatest attention has been given to ionotropic NMDA receptor hypofunction. However, converging data indicates metabotropic glutamate receptors as crucial for cognitive and psychomotor function. The distribution of these receptors in the brain regions related to schizophrenia and their regulatory role in glutamate release make them promising molecular targets for novel antipsychotics. This article reviews the progress in the research on the role of metabotropic glutamate receptors in schizophrenia etiopathology.
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Affiliation(s)
- Waldemar Kryszkowski
- General Psychiatric Ward, Babinski Memorial Hospital in Lodz, 91229 Lodz, Poland;
| | - Tomasz Boczek
- Department of Molecular Neurochemistry, Medical University of Lodz, 92215 Lodz, Poland
- Correspondence:
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19
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Gregory KJ, Goudet C. International Union of Basic and Clinical Pharmacology. CXI. Pharmacology, Signaling, and Physiology of Metabotropic Glutamate Receptors. Pharmacol Rev 2020; 73:521-569. [PMID: 33361406 DOI: 10.1124/pr.119.019133] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Metabotropic glutamate (mGlu) receptors respond to glutamate, the major excitatory neurotransmitter in the mammalian brain, mediating a modulatory role that is critical for higher-order brain functions such as learning and memory. Since the first mGlu receptor was cloned in 1992, eight subtypes have been identified along with many isoforms and splice variants. The mGlu receptors are transmembrane-spanning proteins belonging to the class C G protein-coupled receptor family and represent attractive targets for a multitude of central nervous system disorders. Concerted drug discovery efforts over the past three decades have yielded a wealth of pharmacological tools including subtype-selective agents that competitively block or mimic the actions of glutamate or act allosterically via distinct sites to enhance or inhibit receptor activity. Herein, we review the physiologic and pathophysiological roles for individual mGlu receptor subtypes including the pleiotropic nature of intracellular signal transduction arising from each. We provide a comprehensive analysis of the in vitro and in vivo pharmacological properties of prototypical and commercially available orthosteric agonists and antagonists as well as allosteric modulators, including ligands that have entered clinical trials. Finally, we highlight emerging areas of research that hold promise to facilitate rational design of highly selective mGlu receptor-targeting therapeutics in the future. SIGNIFICANCE STATEMENT: The metabotropic glutamate receptors are attractive therapeutic targets for a range of psychiatric and neurological disorders. Over the past three decades, intense discovery efforts have yielded diverse pharmacological tools acting either competitively or allosterically, which have enabled dissection of fundamental biological process modulated by metabotropic glutamate receptors and established proof of concept for many therapeutic indications. We review metabotropic glutamate receptor molecular pharmacology and highlight emerging areas that are offering new avenues to selectively modulate neurotransmission.
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Affiliation(s)
- Karen J Gregory
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia (K.J.G.) and Institut de Génomique Fonctionnelle (IGF), University of Montpellier, Centre National de la Recherche Scientifique (CNRS), Institut National de la Sante et de la Recherche Medicale (INSERM), Montpellier, France (C.G.)
| | - Cyril Goudet
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia (K.J.G.) and Institut de Génomique Fonctionnelle (IGF), University of Montpellier, Centre National de la Recherche Scientifique (CNRS), Institut National de la Sante et de la Recherche Medicale (INSERM), Montpellier, France (C.G.)
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20
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Postsynaptic Serine Racemase Regulates NMDA Receptor Function. J Neurosci 2020; 40:9564-9575. [PMID: 33158959 DOI: 10.1523/jneurosci.1525-20.2020] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 10/23/2020] [Accepted: 11/01/2020] [Indexed: 01/03/2023] Open
Abstract
d-serine is the primary NMDAR coagonist at mature forebrain synapses and is synthesized by the enzyme serine racemase (SR). However, our understanding of the mechanisms regulating the availability of synaptic d-serine remains limited. Though early studies suggested d-serine is synthesized and released from astrocytes, more recent studies have demonstrated a predominantly neuronal localization of SR. More specifically, recent work intriguingly suggests that SR may be found at the postsynaptic density, yet the functional implications of postsynaptic SR on synaptic transmission are not yet known. Here, we show an age-dependent dendritic and postsynaptic localization of SR and d-serine by immunohistochemistry and electron microscopy in mouse CA1 pyramidal neurons. In addition, using a single-neuron genetic approach in SR conditional KO mice from both sexes, we demonstrate a cell-autonomous role for SR in regulating synaptic NMDAR function at Schaffer collateral (CA3)-CA1 synapses. Importantly, single-neuron genetic deletion of SR resulted in the elimination of LTP at 1 month of age, which could be rescued by exogenous d-serine. Interestingly, there was a restoration of LTP by 2 months of age that was associated with an upregulation of synaptic GluN2B. Our findings support a cell-autonomous role for postsynaptic neuronal SR in regulating synaptic NMDAR function and suggests a possible autocrine mode of d-serine action.SIGNIFICANCE STATEMENT NMDARs are key regulators of neurodevelopment and synaptic plasticity and are unique in their requirement for binding of a coagonist, which is d-serine at most forebrain synapses. However, our understanding of the mechanisms regulating synaptic d-serine availability remains limited. d-serine is synthesized in the brain by the neuronal enzyme serine racemase (SR). Here, we show dendritic and postsynaptic localization of SR and d-serine in CA1 pyramidal neurons. In addition, using single-neuron genetic deletion of SR, we establish a role of postsynaptic SR in regulating NMDAR function. These results support an autocrine mode of d-serine action at synapses.
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21
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Gubert C, Kong G, Uzungil V, Zeleznikow-Johnston AM, Burrows EL, Renoir T, Hannan AJ. Microbiome Profiling Reveals Gut Dysbiosis in the Metabotropic Glutamate Receptor 5 Knockout Mouse Model of Schizophrenia. Front Cell Dev Biol 2020; 8:582320. [PMID: 33195226 PMCID: PMC7658610 DOI: 10.3389/fcell.2020.582320] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Accepted: 10/08/2020] [Indexed: 01/03/2023] Open
Abstract
Schizophrenia (SZ) is a psychiatric disorder that constitutes one of the top 10 global causes of disability. More recently, a potential pathogenic role for the gut microbial community (microbiota) has been highlighted, with numerous studies describing dysregulated microbial profiles in SZ patients when compared to healthy controls. However, no animal model of SZ has previously recapitulated the gut dysbiosis observed clinically. Since the metabotropic glutamate receptor 5 (mGlu5) knockout mice provide a preclinical model of SZ with strong face and predictive validity, in the present study we performed gut microbiome profiling of mGlu5 knockout (KO) and wild-type (WT) mice by 16S rRNA sequencing of bacterial genomic DNA from fecal samples, analyzing bacterial diversity and taxonomic composition, as well as gastrointestinal parameters as indicators of gut function. We found a significant genotype difference in microbial beta diversity. Analysis of composition of microbiomes (ANCOM) models were performed to evaluate microbiota compositions, which identified a decreased relative abundance of the Erysipelotrichaceae family and Allobaculum genus in this mouse model of SZ. We also identified a signature of bacteria discriminating between the genotypes (KO and WT), consisting of the Erysipelotrichales, Bacteroidales, and Clostridiales orders and macroscopic gut differences. We thus uncovered global differential community composition in the gut microbiota profile between mGlu5 KO and WT mice, outlining the first evidence for gut dysbiosis in a genetic animal model of SZ. Our findings suggest that this widely used preclinical model of SZ also has substantial utility for investigations of gut dysbiosis and associated signaling via the microbiota-gut-brain axis, as potential modulators of SZ pathogenesis. Our discovery opens up new avenues to explore gut dysbiosis and its proposed links to brain dysfunction in SZ, as well as novel therapeutic approaches to this devastating disorder.
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Affiliation(s)
- Carolina Gubert
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Geraldine Kong
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Volkan Uzungil
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | | | - Emma L. Burrows
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Thibault Renoir
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Anthony J. Hannan
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, VIC, Australia
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22
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Sengmany K, Hellyer SD, Christopoulos A, Lapinsky DJ, Leach K, Gregory KJ. Differential contribution of metabotropic glutamate receptor 5 common allosteric binding site residues to biased allosteric agonism. Biochem Pharmacol 2020; 177:114011. [DOI: 10.1016/j.bcp.2020.114011] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 04/29/2020] [Indexed: 01/06/2023]
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23
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Wolosker H, Balu DT. D-Serine as the gatekeeper of NMDA receptor activity: implications for the pharmacologic management of anxiety disorders. Transl Psychiatry 2020; 10:184. [PMID: 32518273 PMCID: PMC7283225 DOI: 10.1038/s41398-020-00870-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 05/04/2020] [Accepted: 05/14/2020] [Indexed: 12/12/2022] Open
Abstract
Fear, anxiety, and trauma-related disorders, including post-traumatic stress disorder (PTSD), are quite common and debilitating, with an estimated lifetime prevalence of ~28% in Western populations. They are associated with excessive fear reactions, often including an inability to extinguish learned fear, increased avoidance behavior, as well as altered cognition and mood. There is an extensive literature demonstrating the importance of N-methyl-D-aspartate receptor (NMDAR) function in regulating these behaviors. NMDARs require the binding of a co-agonist, D-serine or glycine, at the glycine modulatory site (GMS) to function. D-serine is now garnering attention as the primary NMDAR co-agonist in limbic brain regions implicated in neuropsychiatric disorders. L-serine is synthesized by astrocytes, which is then transported to neurons for conversion to D-serine by serine racemase (SR), a model we term the 'serine shuttle.' The neuronally-released D-serine is what regulates NMDAR activity. Our review discusses how the systems that regulate the synaptic availability of D-serine, a critical gatekeeper of NMDAR-dependent activation, could be targeted to improve the pharmacologic management of anxiety-related disorders where the desired outcomes are the facilitation of fear extinction, as well as mood and cognitive enhancement.
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Affiliation(s)
- Herman Wolosker
- grid.6451.60000000121102151Department of Biochemistry, Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, 31096 Israel
| | - Darrick T. Balu
- grid.38142.3c000000041936754XDepartment of Psychiatry, Harvard Medical School, Boston, MA 02115 USA ,grid.240206.20000 0000 8795 072XTranslational Psychiatry Laboratory, McLean Hospital, Belmont, MA 02478 USA
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24
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Hellyer SD, Albold S, Sengmany K, Singh J, Leach K, Gregory KJ. Metabotropic glutamate receptor 5 (mGlu 5 )-positive allosteric modulators differentially induce or potentiate desensitization of mGlu 5 signaling in recombinant cells and neurons. J Neurochem 2019; 151:301-315. [PMID: 31376155 DOI: 10.1111/jnc.14844] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 07/17/2019] [Accepted: 07/31/2019] [Indexed: 12/14/2022]
Abstract
Allosteric modulators of metabotropic glutamate receptor 5 (mGlu5 ) are a promising therapeutic strategy for a number of neurological disorders. Multiple mGlu5 -positive allosteric modulator (PAM) chemotypes have been discovered that act as either pure PAMs or as PAM-agonists in recombinant and native cells. While these compounds have been tested in paradigms of receptor activation, their effects on receptor regulatory processes are largely unknown. In this study, acute desensitization of mGlu5 mediated intracellular calcium mobilization by structurally diverse mGlu5 orthosteric and allosteric ligands was assessed in human embryonic kidney 293 cells and primary murine neuronal cultures from both striatum and cortex. We aimed to determine the intrinsic efficacy and modulatory capacity of diverse mGlu5 PAMs [(R)-5-((3-fluorophenyl)ethynyl)-N-(3-hydroxy-3-methylbutan-2-yl)picolinamide (VU0424465), N-cyclobutyl-6-((3-fluorophenyl)ethynyl)picolinamide (VU0360172), 1-(4-(2,4-difluorophenyl)piperazin-1-yl)-2-((4-fluorobenzyl)oxy)ethanone (DPFE), ((4-fluorophenyl) (2-(phenoxymethyl)-6,7-dihydrooxazolo[5,4-c]pyridin-5(4H)-yl)methanone) (VU0409551), 3-Cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide (CDPPB)] on receptor desensitization and whether cellular context influences receptor regulatory processes. Only VU0424465 and VU0409551 induced desensitization alone in human embryonic kidney 293-mGlu5 cells, while all PAMs enhanced (S)-3,5-dihydroxyphenylglycine (DHPG)-induced desensitization. All mGlu5 PAMs induced receptor desensitization alone and enhanced DHPG-induced desensitization in striatal neurons. VU0424465 and VU0360172 were the only PAMs that induced desensitization alone in cortical neurons. With the exception of (CDPPB), PAMs enhanced DHPG-induced desensitization in cortical neurons. Moreover, differential apparent affinities, efficacies, and cooperativities with DHPG were observed for VU0360172, VU0409551, and VU0424465 when comparing receptor activation and desensitization in a cell type-dependent manner. These data indicate that biased mGlu5 allosteric modulator pharmacology extends to receptor regulatory processes in a tissue dependent manner, adding yet another layer of complexity to rational mGlu5 drug discovery.
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Affiliation(s)
- Shane D Hellyer
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia
| | - Sabine Albold
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia
| | - Kathy Sengmany
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia
| | - Junaid Singh
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia
| | - Katie Leach
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia
| | - Karen J Gregory
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia
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25
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Huang X, Wang M, Zhang Q, Chen X, Wu J. The role of glutamate receptors in attention-deficit/hyperactivity disorder: From physiology to disease. Am J Med Genet B Neuropsychiatr Genet 2019; 180:272-286. [PMID: 30953404 DOI: 10.1002/ajmg.b.32726] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 02/12/2019] [Accepted: 03/19/2019] [Indexed: 12/15/2022]
Abstract
Attention-deficit hyperactivity disorder (ADHD) is the most common psychiatric disorder in children and adolescents, which is characterized by behavioral problems such as attention deficit, hyperactivity, and impulsivity. As the receptors of the major excitatory neurotransmitter in the mammalian central nervous system (CNS), glutamate receptors (GluRs) are strongly linked to normal brain functioning and pathological processes. Extensive investigations have been made about the structure, function, and regulation of GluR family, describing evidences that support the disruption of these mechanisms in mental disorders, including ADHD. In this review, we briefly described the family and function of GluRs in the CNS, and discussed what is recently known about the role of GluRs in ADHD, that including GluR genes, animal models, and the treatment, which would help us further elucidate the etiology of ADHD.
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Affiliation(s)
- Xin Huang
- Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Department of Epidemiology and Biostatistics, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Min Wang
- Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Department of Epidemiology and Biostatistics, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qi Zhang
- Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Department of Epidemiology and Biostatistics, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xinzhen Chen
- Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Department of Epidemiology and Biostatistics, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jing Wu
- Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Department of Epidemiology and Biostatistics, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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26
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Xiang Z, Lv X, Maksymetz J, Stansley BJ, Ghoshal A, Gogliotti RG, Niswender CM, Lindsley CW, Conn PJ. mGlu 5 Positive Allosteric Modulators Facilitate Long-Term Potentiation via Disinhibition Mediated by mGlu 5-Endocannabinoid Signaling. ACS Pharmacol Transl Sci 2019; 2:198-209. [PMID: 31259318 PMCID: PMC6591772 DOI: 10.1021/acsptsci.9b00017] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Indexed: 11/29/2022]
Abstract
Metabotropic glutamate (mGlu) receptor type 5 (mGlu5) positive allosteric modulators (PAMs) enhance hippocampal long-term potentiation (LTP) and have cognition-enhancing effects in animal models. These effects were initially thought to be mediated by potentiation of mGlu5 modulation of N-methyl-d-aspartate receptor (NMDAR) currents. However, a biased mGlu5 PAM that potentiates Gαq-dependent mGlu5 signaling, but not mGlu5 modulation of NMDAR currents, retains cognition-enhancing effects in animal models, suggesting that potentiation of NMDAR currents is not required for these in vivo effects of mGlu5 PAMs. However, it is not clear whether the potentiation of NMDAR currents is critical for the ability of mGlu5 PAMs to enhance hippocampal LTP. We now report the characterization of effects of two structurally distinct mGlu5 PAMs, VU-29 and VU0092273, on NMDAR currents and hippocampal LTP. As with other mGlu5 PAMs that do not display observable bias for potentiation of NMDAR currents, VU0092273 enhanced both mGlu5 modulation of NMDAR currents and induction of LTP at the hippocampal Schaffer collateral (SC)-CA1 synapse. In contrast, VU-29 did not potentiate mGlu5 modulation of NMDAR currents but induced robust potentiation of hippocampal LTP. Interestingly, both VU-29 and VU0092273 suppressed evoked inhibitory postsynaptic currents (eIPSCs) in CA1 pyramidal cells, and this effect was blocked by the cannabinoid receptor type 1 (CB1) antagonist AM251. Furthermore, AM251 blocked the ability of both mGlu5 PAMs to enhance LTP. Finally, both PAMs failed to enhance LTP in mice with the restricted genetic deletion of mGlu5 in CA1 pyramidal cells. Taken together with previous findings, these results suggest that enhancement of LTP by mGlu5 PAMs does not depend on mGlu5 modulation of NMDAR currents but is mediated by a previously established mechanism in which mGlu5 in CA1 pyramidal cells induces endocannabinoid release and CB1-dependent disinhibition.
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Affiliation(s)
- Zixiu Xiang
- Department of Pharmacology, Vanderbilt Center for Neuroscience Drug Discovery,Department of Chemistry, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Xiaohui Lv
- Department of Pharmacology, Vanderbilt Center for Neuroscience Drug Discovery,Department of Chemistry, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - James Maksymetz
- Department of Pharmacology, Vanderbilt Center for Neuroscience Drug Discovery,Department of Chemistry, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Branden J Stansley
- Department of Pharmacology, Vanderbilt Center for Neuroscience Drug Discovery,Department of Chemistry, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Ayan Ghoshal
- Department of Pharmacology, Vanderbilt Center for Neuroscience Drug Discovery,Department of Chemistry, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Rocco G Gogliotti
- Department of Pharmacology, Vanderbilt Center for Neuroscience Drug Discovery,Department of Chemistry, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Colleen M Niswender
- Department of Pharmacology, Vanderbilt Center for Neuroscience Drug Discovery,Department of Chemistry, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Craig W Lindsley
- Department of Pharmacology, Vanderbilt Center for Neuroscience Drug Discovery,Department of Chemistry, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - P Jeffrey Conn
- Department of Pharmacology, Vanderbilt Center for Neuroscience Drug Discovery,Department of Chemistry, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
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27
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Uno Y, Coyle JT. Glutamate hypothesis in schizophrenia. Psychiatry Clin Neurosci 2019; 73:204-215. [PMID: 30666759 DOI: 10.1111/pcn.12823] [Citation(s) in RCA: 195] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 01/08/2019] [Accepted: 01/16/2019] [Indexed: 12/13/2022]
Abstract
Schizophrenia is a chronic and severe psychiatric disorder that has profound impact on an individual's life and on society. Thus, developing more effective therapeutic interventions is essential. Over the past quarter-century, an abundance of evidence from pharmacologic challenges, post-mortem studies, brain imaging, and genetic studies supports the role of glutamatergic dysregulation in the pathophysiology of schizophrenia, and the results of recent randomized clinical trials based on this evidence have yielded promising results. In this article, we review the evidence that alterations in glutamatergic neurotransmission, especially focusing on the N-methyl-d-aspartate receptor (NMDAR) function, may be a critical causative feature of schizophrenia, how this contributes to pathologic circuit function in the brain, and how these insights are revealing whole new avenues for treatment development that could reduce treatment-resistant symptoms, which account for persistent disability.
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Affiliation(s)
- Yota Uno
- Department of Psychiatry, Harvard Medical School, Boston, USA.,Laboratory for Psychiatric and Molecular Neuroscience, McLean Hospital, Belmont, USA.,Department of Psychology, University of Bath, Bath, UK
| | - Joseph T Coyle
- Department of Psychiatry, Harvard Medical School, Boston, USA.,Laboratory for Psychiatric and Molecular Neuroscience, McLean Hospital, Belmont, USA
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28
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Huang CCY, Muszynski KJ, Bolshakov VY, Balu DT. Deletion of Dtnbp1 in mice impairs threat memory consolidation and is associated with enhanced inhibitory drive in the amygdala. Transl Psychiatry 2019; 9:132. [PMID: 30967545 PMCID: PMC6456574 DOI: 10.1038/s41398-019-0465-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 03/23/2019] [Indexed: 11/19/2022] Open
Abstract
Schizophrenia is a severe and highly heritable disorder. Dystrobrevin-binding protein 1 (DTNBP1), also known as dysbindin-1, has been implicated in the pathophysiology of schizophrenia. Specifically, dysbindin-1 mRNA and protein expression are decreased in the brains of subjects with this disorder. Mice lacking dysbinidn-1 also display behavioral phenotypes similar to those observed in schizophrenic patients. However, it remains unknown whether deletion of dysbindin-1 impacts functions of the amygdala, a brain region that is critical for emotional processing, which is disrupted in patients with schizophrenia. Here, we show that dysbindin-1 is expressed in both excitatory and inhibitory neurons of the basolateral amygdala (BLA). Deletion of dysbindin-1 in male mice (Dys-/-) impaired cued and context-dependent threat memory, without changes in measures of anxiety. The behavioral deficits observed in Dys-/- mice were associated with perturbations in the BLA, including the enhancement of GABAergic inhibition of pyramidal neurons, increased numbers of parvalbumin interneurons, and morphological abnormalities of dendritic spines on pyramidal neurons. Our findings highlight an important role for dysbindin-1 in the regulation of amygdalar function and indicate that enhanced inhibition of BLA pyramidal neuron activity may contribute to the weakened threat memory expression observed in Dys-/- mice.
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Affiliation(s)
- Cathy C Y Huang
- Department of Psychiatry, Harvard Medical School, Boston, MA, USA.
- Translational Psychiatry laboratory, McLean Hospital, Belmont, MA, USA.
- Department of Life Sciences, National Central University, Taoyuan, Taiwan.
| | - Kevin J Muszynski
- Translational Psychiatry laboratory, McLean Hospital, Belmont, MA, USA
| | - Vadim Y Bolshakov
- Department of Psychiatry, Harvard Medical School, Boston, MA, USA
- Cellular Neurobiology laboratory, McLean Hospital, Belmont, MA, USA
| | - Darrick T Balu
- Department of Psychiatry, Harvard Medical School, Boston, MA, USA.
- Translational Psychiatry laboratory, McLean Hospital, Belmont, MA, USA.
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29
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Stansley BJ, Conn PJ. Neuropharmacological Insight from Allosteric Modulation of mGlu Receptors. Trends Pharmacol Sci 2019; 40:240-252. [PMID: 30824180 PMCID: PMC6445545 DOI: 10.1016/j.tips.2019.02.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 02/06/2019] [Accepted: 02/06/2019] [Indexed: 12/11/2022]
Abstract
The metabotropic glutamate (mGlu) receptors are a family of G-protein-coupled receptors (GPCRs) that regulate cell physiology throughout the nervous system. The potential of mGlu receptors as therapeutic targets has been bolstered by current research that has provided insight into the diverse modes of mGlu activation and signaling. In particular, the allosteric modulation of mGlu receptors represents a major area of focus in studies of basic pharmacology as well as drug development, largely due to the high subtype specificity achievable by targeting allosteric sites on mGlu receptors. These provide sophisticated regulation of neuronal excitability and synaptic transmission to influence behavioral output. Here, we review how these allosteric mechanisms have been leveraged preclinically to demonstrate the therapeutic potential of allosteric modulators for neurological and neuropsychiatric disorders, such as autism, cognitive impairment, Parkinson's disease (PD), stress, and schizophrenia.
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Affiliation(s)
- Branden J Stansley
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - P Jeffrey Conn
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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30
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Coughlin Q, Hopper AT, Blanco MJ, Tirunagaru V, Robichaud AJ, Doller D. Allosteric Modalities for Membrane-Bound Receptors: Insights from Drug Hunting for Brain Diseases. J Med Chem 2019; 62:5979-6002. [PMID: 30721063 DOI: 10.1021/acs.jmedchem.8b01651] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Medicinal chemists are accountable for embedding the appropriate drug target profile into the molecular architecture of a clinical candidate. An accurate characterization of the functional effects following binding of a drug to its biological target is a fundamental step in the discovery of new medicines, informing the translation of preclinical efficacy and safety observations into human trials. Membrane-bound proteins, particularly ion channels and G protein-coupled receptors (GPCRs), are biological targets prone to allosteric modulation. Investigations using allosteric drug candidates and chemical tools suggest that their functional effects may be tailored with a high degree of translational alignment, making them molecular tools to correct pathophysiological functional tone and enable personalized medicine when a causative target-to-disease link is known. We present select examples of functional molecular fine-tuning of allosterism and discuss consequences relevant to drug design.
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31
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Puhl MD, Desai RI, Takagi S, Presti KT, Doyle MR, Donahue RJ, Landino SM, Bergman J, Carlezon WA, Coyle JT. N-Methyl-d-aspartate receptor co-agonist availability affects behavioral and neurochemical responses to cocaine: insights into comorbid schizophrenia and substance abuse. Addict Biol 2019; 24:40-50. [PMID: 29168271 DOI: 10.1111/adb.12577] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 10/16/2017] [Indexed: 12/19/2022]
Abstract
Both schizophrenia (SZ) and substance abuse (SA) exhibit significant heritability. Moreover, N-methyl-d-aspartate receptors (NMDARs) have been implicated in the pathophysiology of both SZ and SA. We hypothesize that the high prevalence of comorbid SA in SZ is due to dysfunction of NMDARs caused by shared risk genes. We used transgenic mice with a null mutation of the gene encoding serine racemase (SR), the enzyme that synthesizes the NMDAR co-agonist d-serine and an established risk gene for SZ, to recreate the pathology of SZ. We determined the effect of NMDAR hypofunction resulting from the absence of d-serine on motivated behavior by using intracranial self-stimulation and neurotransmitter release in the nucleus accumbens by using in vivo microdialysis. Compared with wild-type mice, SR-/- mice exhibited similar baseline intracranial self-stimulation thresholds but were less sensitive to the threshold-lowering (rewarding) and the performance-elevating (stimulant) effects of cocaine. While basal dopamine (DA) and glutamate release were elevated in the nucleus accumbens of SR-/- mice, cocaine-induced increases in DA and glutamate release were blunted. γ-Amino-butyric acid efflux was unaffected in the SR-/- mice. Together, these findings suggest that the impaired NMDAR function and a consequent decrease in sensitivity to cocaine effects on behavior are mediated by blunted DA and glutamate responses normally triggered by the drug. Projected to humans, NMDAR hypofunction due to mutations in SR or other genes impacting glutamatergic function in SZ may render abused substances less potent and effective, thus requiring higher doses to achieve a hedonic response, resulting in elevated drug exposure and increased dependence/addiction.
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Affiliation(s)
- Matthew D. Puhl
- Department of Psychiatry; Harvard Medical School; Boston MA USA
- Laboratory for Psychiatric and Molecular Neuroscience; McLean Hospital; Belmont MA USA
| | - Rajeev I. Desai
- Department of Psychiatry; Harvard Medical School; Boston MA USA
- Preclinical Pharmacology Laboratory; McLean Hospital; Belmont MA USA
| | - Shunsuke Takagi
- Department of Psychiatry; Harvard Medical School; Boston MA USA
- Laboratory for Psychiatric and Molecular Neuroscience; McLean Hospital; Belmont MA USA
- Department of Psychiatry and Behavioral Sciences, Graduate School of Medical and Dental Sciences; Tokyo Medical and Dental University; Tokyo Japan
| | - Kendall T. Presti
- Department of Psychiatry; Harvard Medical School; Boston MA USA
- Laboratory for Psychiatric and Molecular Neuroscience; McLean Hospital; Belmont MA USA
| | - Michelle R. Doyle
- Department of Psychiatry; Harvard Medical School; Boston MA USA
- Preclinical Pharmacology Laboratory; McLean Hospital; Belmont MA USA
| | - Rachel J. Donahue
- Department of Psychiatry; Harvard Medical School; Boston MA USA
- Behavioral Genetics Laboratory; McLean Hospital; Belmont MA USA
| | - Samantha M. Landino
- Department of Psychiatry; Harvard Medical School; Boston MA USA
- Behavioral Genetics Laboratory; McLean Hospital; Belmont MA USA
| | - Jack Bergman
- Department of Psychiatry; Harvard Medical School; Boston MA USA
- Preclinical Pharmacology Laboratory; McLean Hospital; Belmont MA USA
| | - William A. Carlezon
- Department of Psychiatry; Harvard Medical School; Boston MA USA
- Behavioral Genetics Laboratory; McLean Hospital; Belmont MA USA
| | - Joseph T. Coyle
- Department of Psychiatry; Harvard Medical School; Boston MA USA
- Laboratory for Psychiatric and Molecular Neuroscience; McLean Hospital; Belmont MA USA
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Nicoletti F, Orlando R, Di Menna L, Cannella M, Notartomaso S, Mascio G, Iacovelli L, Matrisciano F, Fazio F, Caraci F, Copani A, Battaglia G, Bruno V. Targeting mGlu Receptors for Optimization of Antipsychotic Activity and Disease-Modifying Effect in Schizophrenia. Front Psychiatry 2019; 10:49. [PMID: 30890967 PMCID: PMC6413697 DOI: 10.3389/fpsyt.2019.00049] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 01/23/2019] [Indexed: 01/03/2023] Open
Abstract
Metabotropic glutamate (mGlu) receptors are considered as candidate drug targets for the treatment of schizophrenia. These receptors form a family of eight subtypes (mGlu1 to -8), of which mGlu1 and -5 are coupled to Gq/11, and all other subtypes are coupled to Gi/o. Here, we discuss the possibility that selective ligands of individual mGlu receptor subtypes may be effective in controlling the core symptoms of schizophrenia, and, in some cases, may impact mechanisms underlying the progression of the disorder. Recent evidence indicates that activation of mGlu1 receptors inhibits dopamine release in the meso-striatal system. Hence, selective positive allosteric modulators (PAMs) of mGlu1 receptors hold promise for the treatment of positive symptoms of schizophrenia. mGlu5 receptors are widely expressed in the CNS and regulate the activity of cells that are involved in the pathophysiology of schizophrenia, such as cortical GABAergic interneurons and microglial cells. mGlu5 receptor PAMs are under development for the treatment of schizophrenia and cater the potential to act as disease modifiers by restraining neuroinflammation. mGlu2 receptors have attracted considerable interest because they negatively modulate 5-HT2A serotonin receptor signaling in the cerebral cortex. Both mGlu2 receptor PAMs and orthosteric mGlu2/3 receptor agonists display antipsychotic-like activity in animal models, and the latter drugs are inactive in mice lacking mGlu2 receptors. So far, mGlu3 receptors have been left apart as drug targets for schizophrenia. However, activation of mGlu3 receptors boosts mGlu5 receptor signaling, supports neuronal survival, and drives microglial cells toward an antiinflammatory phenotype. This strongly encourages research of mGlu3 receptors in schizophrenia. Finally, preclical studies suggest that mGlu4 receptors might be targeted by novel antipsychotic drugs, whereas studies of mGlu7 and mGlu8 receptors in animal models of psychosis are still at their infancy.
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Affiliation(s)
- Ferdinando Nicoletti
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy.,IRCCS Neuromed, Pozzilli, Italy
| | - Rosamaria Orlando
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
| | | | | | | | | | - Luisa Iacovelli
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
| | - Francesco Matrisciano
- Department of Psychiatry, The Psychiatric Institute, College of Medicine, University of Illinois, Chicago, IL, United States
| | | | - Filippo Caraci
- Department of Drug Sciences, University of Catania, Catania, Italy.,Oasi Research Institute (IRCCS), Troina, Italy
| | - Agata Copani
- Department of Drug Sciences, University of Catania, Catania, Italy.,Institute of Biostructure and Bioimaging, National Research Council, Catania, Italy
| | | | - Valeria Bruno
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy.,IRCCS Neuromed, Pozzilli, Italy
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Hwang S, Lee SE, Ahn SG, Lee GH. Psoralidin Stimulates Expression of Immediate-Early Genes and Synapse Development in Primary Cortical Neurons. Neurochem Res 2018; 43:2460-2472. [DOI: 10.1007/s11064-018-2674-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 10/23/2018] [Accepted: 10/25/2018] [Indexed: 12/29/2022]
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34
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Biased agonism and allosteric modulation of metabotropic glutamate receptor 5. Clin Sci (Lond) 2018; 132:2323-2338. [PMID: 30389826 DOI: 10.1042/cs20180374] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 10/03/2018] [Accepted: 10/05/2018] [Indexed: 12/18/2022]
Abstract
Metabotropic glutamate receptors belong to class C G-protein-coupled receptors and consist of eight subtypes that are ubiquitously expressed throughout the central nervous system. In recent years, the metabotropic glutamate receptor subtype 5 (mGlu5) has emerged as a promising target for a broad range of psychiatric and neurological disorders. Drug discovery programs targetting mGlu5 are primarily focused on development of allosteric modulators that interact with sites distinct from the endogenous agonist glutamate. Significant efforts have seen mGlu5 allosteric modulators progress into clinical trials; however, recent failures due to lack of efficacy or adverse effects indicate a need for a better understanding of the functional consequences of mGlu5 allosteric modulation. Biased agonism is an interrelated phenomenon to allosterism, describing how different ligands acting through the same receptor can differentially influence signaling to distinct transducers and pathways. Emerging evidence demonstrates that allosteric modulators can induce biased pharmacology at the level of intrinsic agonism as well as through differential modulation of orthosteric agonist-signaling pathways. Here, we present key considerations in the discovery and development of mGlu5 allosteric modulators and the opportunities and pitfalls offered by biased agonism and modulation.
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35
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Mechanisms underlying prelimbic prefrontal cortex mGlu 3/mGlu 5-dependent plasticity and reversal learning deficits following acute stress. Neuropharmacology 2018; 144:19-28. [PMID: 30326237 DOI: 10.1016/j.neuropharm.2018.10.013] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 09/22/2018] [Accepted: 10/12/2018] [Indexed: 01/09/2023]
Abstract
Stress can precipitate or worsen symptoms of many psychiatric illnesses. Dysregulation of the prefrontal cortex (PFC) glutamate system may underlie these disruptions and restoring PFC glutamate signaling has emerged as a promising avenue for the treatment of stress disorders. Recently, we demonstrated that activation of metabotropic glutamate receptor subtype 3 (mGlu3) induces a postsynaptic form of long-term depression (LTD) that is dependent on the activity of another subtype, mGlu5. Stress exposure disrupted this plasticity, but the underlying signaling mechanisms and involvement in higher-order cognition have not yet been investigated. Acute stress was applied by 20-min restraint and early reversal learning was evaluated in an operant-based food-seeking task. We employed whole-cell patch-clamp recordings of layer 5 prelimbic (PL)-PFC pyramidal cells to examine mGlu3-LTD and several mechanistically distinct mGlu5-dependent functions. Acute stress impaired both mGlu3-LTD and early reversal learning. Interestingly, potentiating mGlu5 signaling with the mGlu5 positive allosteric modulator (PAM) VU0409551 rescued stress-induced deficits in both mGlu3-LTD and reversal learning. Other aspects of PL-PFC mGlu5 function were not disrupted following stress; however, signaling downstream of mGlu5-Homer interactions, phosphoinositide-3-kinase (PI3K), Akt, and glycogen synthase kinase 3β was implicated in these phenomena. These findings demonstrate that acute stress disrupts early reversal learning and PL-PFC-dependent synaptic plasticity and that potentiating mGlu5 function can restore these impairments. These findings provide a framework through which modulating coordinated mGlu3/mGlu5 signaling may confer benefits for the treatment of stress-related psychiatric disorders.
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36
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Stansley BJ, Conn PJ. The therapeutic potential of metabotropic glutamate receptor modulation for schizophrenia. Curr Opin Pharmacol 2018; 38:31-36. [PMID: 29486374 PMCID: PMC5949078 DOI: 10.1016/j.coph.2018.02.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 02/10/2018] [Indexed: 12/21/2022]
Abstract
Accumulating evidence suggests that a dysregulation of the glutamatergic system exists in the brains of schizophrenia patients. The metabotropic glutamate (mGlu) receptors are being investigated as novel drug targets for this disease, and have shown promise in both preclinical and clinical studies. Activation of mGlu5 receptors may be efficacious for several symptom domains (positive, negative, and cognitive) and the potential for targeting mGlu5 receptors has been bolstered by recent research on mitigating toxicity profiles associated with mGlu5 activation. Additionally, genetic profiling of schizophrenia patients suggests that genes encoding for mGlu1 and mGlu3 receptors are altered, prompting preclinical studies that have demonstrated potential antipsychotic and cognitive enhancing effects of agents that activate mGlu1 and mGlu3 receptors, respectively. Development of subtype-specific drugs for the mGlu receptors, such as allosteric modulators, could provide a path forward for more efficacious and tolerable therapeutics for schizophrenia.
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Affiliation(s)
- Branden J Stansley
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - P Jeffrey Conn
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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37
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Serine Racemase and D-serine in the Amygdala Are Dynamically Involved in Fear Learning. Biol Psychiatry 2018; 83:273-283. [PMID: 29025687 PMCID: PMC5806199 DOI: 10.1016/j.biopsych.2017.08.012] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 08/15/2017] [Accepted: 08/16/2017] [Indexed: 02/05/2023]
Abstract
BACKGROUND The amygdala is a central component of the neural circuitry that underlies fear learning. N-methyl-D-aspartate receptor-dependent plasticity in the amygdala is required for pavlovian fear conditioning and extinction. N-methyl-D-aspartate receptor activation requires the binding of a coagonist, D-serine, which is synthesized from L-serine by the neuronal enzyme serine racemase (SR). However, little is known about SR and D-serine function in the amygdala. METHODS We used immunohistochemical methods to characterize the cellular localization of SR and D-serine in the mouse and human amygdala. Using biochemical and molecular techniques, we determined whether trace fear conditioning and extinction engages the SR/D-serine system in the brain. D-serine was administered systemically to mice to evaluate its effect on fear extinction. Finally, we investigated whether the functional single nucleotide polymorphism rs4523957, which is an expression quantitative trait locus of the human serine racemase (SRR) gene, was associated with fear-related phenotypes in a highly traumatized human cohort. RESULTS We demonstrate that approximately half of the neurons in the amygdala express SR, including both excitatory and inhibitory neurons. We find that the acquisition and extinction of fear memory engages the SR/D-serine system in the mouse amygdala and that D-serine administration facilitates fear extinction. We also demonstrate that the SRR single nucleotide polymorphism, rs4523957, is associated with posttraumatic stress disorder in humans, consistent with the facilitatory effect of D-serine on fear extinction. CONCLUSIONS These new findings have important implications for understanding D-serine-mediated N-methyl-D-aspartate receptor plasticity in the amygdala and how this system could contribute to disorders with maladaptive fear circuitry.
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38
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Luoni A, Gass P, Brambilla P, Ruggeri M, Riva MA, Inta D. Altered expression of schizophrenia-related genes in mice lacking mGlu5 receptors. Eur Arch Psychiatry Clin Neurosci 2018; 268:77-87. [PMID: 27581816 DOI: 10.1007/s00406-016-0728-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 08/22/2016] [Indexed: 12/15/2022]
Abstract
The evidence underlying the so-called glutamatergic hypothesis ranges from NMDA receptor hypofunction to an imbalance between excitatory and inhibitory circuits in specific brain structures. Among all glutamatergic system components, metabotropic receptors play a main role in regulating neuronal excitability and synaptic plasticity. Here, we investigated, using qRT-PCR and western blot, consequences in the hippocampus and prefrontal/frontal cortex (PFC/FC) of mice with a genetic deletion of the metabotropic glutamate receptor 5 (mGlu5), addressing key components of the GABAergic and glutamatergic systems. We found that mGlu5 knockout (KO) mice showed a significant reduction of reelin, GAD65, GAD67 and parvalbumin mRNA levels, which is specific for the PFC/FC, and that is paralleled by a significant reduction of protein levels in male KO mice. We next analyzed the main NMDA and AMPA receptor subunits, namely GluN1, GluN2A, GluN2B and GluA1, and we found that mGlu5 deletion determined a significant reduction of their mRNA levels, also within the hippocampus, with differences between the two genders. Our data suggest that neurochemical abnormalities impinging the glutamatergic and GABAergic systems may be responsible for the behavioral phenotype associated with mGlu5 KO animals and point to the close interaction of these molecular players for the development of neuropsychiatric disorders such as schizophrenia. These data could contribute to a better understanding of the involvement of mGlu5 alterations in the molecular imbalance between excitation and inhibition underlying the emergence of a schizophrenic-like phenotype and to understand the potential of mGlu5 modulators in reversing the deficits characterizing the schizophrenic pathology.
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Affiliation(s)
- Alessia Luoni
- Department of Pharmacological and Biomolecular Sciences, Center of Neuropharmacology, Università degli Studi di Milano, Milan, Italy
| | - Peter Gass
- Department of Psychiatry and Psychotherapy, Central Institute of Mental Health Mannheim, Medical Faculty Mannheim, University of Heidelberg, J 5, 68159, Mannheim, Germany
| | - Paolo Brambilla
- Department of Neurosciences and Mental Health, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
| | - Mirella Ruggeri
- Section of Psychiatry, Department of Neurological, Biomedical and Movement Sciences, University of Verona, Verona, Italy
| | - Marco A Riva
- Department of Pharmacological and Biomolecular Sciences, Center of Neuropharmacology, Università degli Studi di Milano, Milan, Italy
| | - Dragos Inta
- Department of Psychiatry and Psychotherapy, Central Institute of Mental Health Mannheim, Medical Faculty Mannheim, University of Heidelberg, J 5, 68159, Mannheim, Germany. .,Department of Psychiatry (UPK), University of Basel, Wilhelm Klein-Str. 27, 4012, Basel, Switzerland.
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39
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Coyle JT, Balu DT. The Role of Serine Racemase in the Pathophysiology of Brain Disorders. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2017; 82:35-56. [PMID: 29413527 PMCID: PMC5821497 DOI: 10.1016/bs.apha.2017.10.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The N-methyl-d-aspartate receptor (NMDAR) is unique in requiring two agonists to bind simultaneously to open its cation channel: the neurotransmitter, glutamate, and the coagonists, glycine, or d-serine. The Snyder laboratory was the first to clone serine racemase (SR), the enzyme that synthesizes d-serine, and to localize it immunocytochemically. Our laboratory has focused on the role of d-serine in brain disorders. Silencing the expression of SR, a risk gene for schizophrenia (SCZ), in mice (SR-/-), results in a phenotype that closely resembles SCZ including: cortical atrophy, reduced dendritic spine density and complexity, downregulation of parvalbumin-positive cortical GABAergic neurons, and cognitive impairments. This pathology can be reversed by treatment of SR-/- mice with d-serine in adulthood. SR-/- mice also exhibit abnormal response toward abusable substances, such as stimulants. They show reduced behavioral sensitization to d-amphetamine, but fail to extinguish it. Place preference to cocaine is altered, and the hedonic response to it is profoundly impaired as assessed by intracranial self-stimulation. d-cycloserine, a partial agonist at the NMDAR glycine modulatory site, shows therapeutic benefit for treating pathologic anxiety in combination with behavioral therapies. Studies in vitro with cortical culture and in vivo with middle cerebral artery occlusion show that silencing SR provides substantial protection against ischemic neuronal death. Finally, the switch of SR expression from neurons to reactive astrocytes after closed head trauma accounts for the reduced in vivo neuroplasticity, electroencephalogram abnormalities, and cognitive impairments.
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Affiliation(s)
- Joseph T Coyle
- Harvard Medical School, Boston, MA, United States; McLean Hospital, Belmont, MA, United States.
| | - Darrick T Balu
- Harvard Medical School, Boston, MA, United States; McLean Hospital, Belmont, MA, United States
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40
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Ghoshal A, Moran SP, Dickerson JW, Joffe ME, Grueter BA, Xiang Z, Lindsley CW, Rook JM, Conn PJ. Role of mGlu 5 Receptors and Inhibitory Neurotransmission in M 1 Dependent Muscarinic LTD in the Prefrontal Cortex: Implications in Schizophrenia. ACS Chem Neurosci 2017; 8:2254-2265. [PMID: 28679049 DOI: 10.1021/acschemneuro.7b00167] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Selective potentiation of the mGlu5 subtype of metabotropic glutamate (mGlu) receptor using positive allosteric modulators (PAMs) has robust cognition-enhancing effects in rodent models that are relevant for schizophrenia. Until recently, these effects were thought to be due to potentiation of mGlu5-induced modulation of NMDA receptor (NMDAR) currents and NMDAR-dependent synaptic plasticity. However, "biased" mGlu5 PAMs that do not potentiate mGlu5 effects on NMDAR currents show efficacy that is similar to that of prototypical mGlu5 PAMs, suggesting that NMDAR-independent mechanisms must be involved in these actions. We now report that synaptic activation of mGlu5 is required for a form of long-term depression (mLTD) in mouse prefrontal cortex (PFC) that is induced by activation of M1 muscarinic acetylcholine (mAChR) receptors, which was previously thought to be independent of mGlu5 activation. Interestingly, a biased mGlu5 PAM, VU0409551, that does not potentiate mGlu5 modulation of NMDAR currents, potentiated induction of mLTD. Furthermore, coactivation of mGlu5 and M1 receptors increased GABAA-dependent inhibitory tone in the PFC pyramidal neurons, which likely contributes to the observed mLTD. Finally, systemic administration of the biased mGlu5 PAM reversed deficits in mLTD and associated cognitive deficits in a model of cortical disruption caused by repeated phencyclidine exposure that is relevant for schizophrenia and was previously shown to be responsive to selective M1 muscarinic receptor PAMs. These studies provide exciting new insights into a novel mechanism by which mGlu5 PAMs can reverse deficits in PFC function and cognition that is independent of modulation of NMDAR currents.
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Affiliation(s)
- Ayan Ghoshal
- Department of Pharmacology,
Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, Tennessee 37240, United States
| | - Sean P. Moran
- Department of Pharmacology,
Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, Tennessee 37240, United States
| | - Jonathan W. Dickerson
- Department of Pharmacology,
Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, Tennessee 37240, United States
| | - Max E. Joffe
- Department of Pharmacology,
Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, Tennessee 37240, United States
| | - Brad A. Grueter
- Department of Pharmacology,
Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, Tennessee 37240, United States
| | - Zixiu Xiang
- Department of Pharmacology,
Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, Tennessee 37240, United States
| | - Craig W. Lindsley
- Department of Pharmacology,
Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, Tennessee 37240, United States
| | - Jerri M. Rook
- Department of Pharmacology,
Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, Tennessee 37240, United States
| | - P. Jeffrey Conn
- Department of Pharmacology,
Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, Tennessee 37240, United States
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41
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Tyler MW, Yourish HB, Ionescu DF, Haggarty SJ. Classics in Chemical Neuroscience: Ketamine. ACS Chem Neurosci 2017; 8:1122-1134. [PMID: 28418641 DOI: 10.1021/acschemneuro.7b00074] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Ketamine, a molecule of many faces, has contributed immeasurably to numerous realms of clinical practice and scientific inquiry. From anesthesia and analgesia to depression and schizophrenia, it continues to shed light on the molecular underpinnings of pain, consciousness, and the pathophysiology of neuropsychiatric disorders. In particular, research on ketamine's mechanism of action is providing new hope in the search for therapies for treatment-resistant depression and affords insights into disorders of glutamatergic dysfunction. In this Review, we will cover aspects of ketamine's synthesis, manufacturing, metabolism, pharmacology, approved and off-label indications, and adverse effects. We will also discuss the captivating history of this molecule, its influence on neuropsychiatry, and its potential to advance the fields of chemical neuroscience and neuropharmacology.
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Affiliation(s)
- Marshall W. Tyler
- Chemical Neurobiology Laboratory, Center for Genomic Medicine, Massachusetts General Hospital, Harvard Medical School, Chemical Biology Program, Boston, Massachusetts 02114, United States
| | - Harmony B. Yourish
- University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, United States
| | - Dawn F. Ionescu
- Depression Clinical and Research Program, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Stephen J. Haggarty
- Chemical Neurobiology Laboratory, Center for Genomic Medicine, Massachusetts General Hospital, Harvard Medical School, Chemical Biology Program, Boston, Massachusetts 02114, United States
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42
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Foster DJ, Conn PJ. Allosteric Modulation of GPCRs: New Insights and Potential Utility for Treatment of Schizophrenia and Other CNS Disorders. Neuron 2017; 94:431-446. [PMID: 28472649 PMCID: PMC5482176 DOI: 10.1016/j.neuron.2017.03.016] [Citation(s) in RCA: 163] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 03/02/2017] [Accepted: 03/09/2017] [Indexed: 01/11/2023]
Abstract
G-protein-coupled receptors (GPCRs) play critical roles in regulating brain function. Recent advances have greatly expanded our understanding of these receptors as complex signaling machines that can adopt numerous conformations and modulate multiple downstream signaling pathways. While agonists and antagonists have traditionally been pursued to target GPCRs, allosteric modulators provide several mechanistic advantages, including the ability to distinguish between closely related receptor subtypes. Recently, the discovery of allosteric ligands that confer bias and modulate some, but not all, of a given receptor's downstream signaling pathways can provide pharmacological modulation of brain circuitry with remarkable precision. In addition, allosteric modulators with unprecedented specificity have been developed that can differentiate between subpopulations of a given receptor subtype based on the receptor's dimerization state. These advances are not only providing insight into the biological roles of specific receptor populations, but hold great promise for treating numerous CNS disorders.
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Affiliation(s)
- Daniel J Foster
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA
| | - P Jeffrey Conn
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA.
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43
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Maksymetz J, Moran SP, Conn PJ. Targeting metabotropic glutamate receptors for novel treatments of schizophrenia. Mol Brain 2017; 10:15. [PMID: 28446243 PMCID: PMC5405554 DOI: 10.1186/s13041-017-0293-z] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 04/04/2017] [Indexed: 12/22/2022] Open
Abstract
Support for the N-methyl-D-aspartate receptor (NMDAR) hypofunction hypothesis of schizophrenia has led to increasing focus on restoring proper glutamatergic signaling as an approach for treatment of this devastating disease. The ability of metabotropic glutamate (mGlu) receptors to modulate glutamatergic neurotransmission has thus attracted considerable attention for the development of novel antipsychotics. Consisting of eight subtypes classified into three groups based on sequence homology, signal transduction, and pharmacology, the mGlu receptors provide a wide range of targets to modulate NMDAR function as well as glutamate release. Recently, allosteric modulators of mGlu receptors have been developed that allow unprecedented selectivity among subtypes, not just groups, facilitating the investigation of the effects of subtype-specific modulation. In preclinical animal models, positive allosteric modulators (PAMs) of the group I mGlu receptor mGlu5 have efficacy across all three symptom domains of schizophrenia (positive, negative, and cognitive). The discovery and development of mGlu5 PAMs that display unique signal bias suggests that efficacy can be retained while avoiding the neurotoxic effects of earlier compounds. Interestingly, mGlu1 negative allosteric modulators (NAMs) appear efficacious in positive symptom models of the disease but are still in early preclinical development. While selective group II mGlu receptor (mGlu2/3) agonists have reached clinical trials but were unsuccessful, specific mGlu2 or mGlu3 receptor targeting still hold great promise. Genetic studies implicated mGlu2 in the antipsychotic effects of group II agonists and mGlu2 PAMs have since entered into clinical trials. Additionally, mGlu3 appears to play an important role in cognition, may confer neuroprotective effects, and thus is a promising target to alleviate cognitive deficits in schizophrenia. Although group III mGlu receptors (mGlu4/6/7/8) have attracted less attention, mGlu4 agonists and PAMs appear to have efficacy across all three symptoms domains in preclinical models. The recent discovery of heterodimers comprising mGlu2 and mGlu4 may explain the efficacy of mGlu4 selective compounds but this remains to be determined. Taken together, compounds targeting mGlu receptors, specifically subtype-selective allosteric modulators, provide a compelling alternative approach to fill the unmet clinical needs for patients with schizophrenia.
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Affiliation(s)
- James Maksymetz
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232 USA
- Vanderbilt Center for Neuroscience Drug Discovery, Nashville, TN 37232 USA
| | - Sean P. Moran
- Vanderbilt Center for Neuroscience Drug Discovery, Nashville, TN 37232 USA
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37232 USA
| | - P. Jeffrey Conn
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232 USA
- Vanderbilt Center for Neuroscience Drug Discovery, Nashville, TN 37232 USA
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37232 USA
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Faustino AI, Tacão-Monteiro A, Oliveira RF. Mechanisms of social buffering of fear in zebrafish. Sci Rep 2017; 7:44329. [PMID: 28361887 PMCID: PMC5374490 DOI: 10.1038/srep44329] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 02/07/2017] [Indexed: 11/13/2022] Open
Abstract
Some humans thrive whereas others resign when exposed to threatening situations throughout life. Social support has been identified as an important modulator of these discrepancies in human behaviour, and other social animals also exhibit phenomena in which individuals recover better from aversive events when conspecifics are present - aka social buffering. Here we studied social buffering in zebrafish, by exposing focal fish to an aversive stimulus (alarm substance - AS) either in the absence or presence of conspecific cues. When exposed to AS in the presence of both olfactory (shoal water) and visual (sight of shoal) conspecific cues, focal fish exhibited a lower fear response than when tested alone, demonstrating social buffering in zebrafish. When separately testing each cue's effectiveness, we verified that the visual cue was more effective than the olfactory in reducing freezing in a persistent threat scenario. Finally, we verified that social buffering was independent of shoal size and coincided with a distinct pattern of co-activation of brain regions known to be involved in mammalian social buffering. Thus, this study suggests a shared evolutionary origin for social buffering in vertebrates, bringing new evidence on the behavioural, sensory and neural mechanisms underlying this phenomenon.
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Affiliation(s)
- Ana I. Faustino
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, Oeiras 2780-156, Portugal
- ISPA–Instituto Universitário, Rua Jardim do Tabaco 34, Lisboa 1149-041, Portugal
- Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Avenida Brasília, Lisboa 1400-038, Portugal
| | - André Tacão-Monteiro
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, Oeiras 2780-156, Portugal
- Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Avenida Brasília, Lisboa 1400-038, Portugal
| | - Rui F. Oliveira
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, Oeiras 2780-156, Portugal
- ISPA–Instituto Universitário, Rua Jardim do Tabaco 34, Lisboa 1149-041, Portugal
- Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Avenida Brasília, Lisboa 1400-038, Portugal
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Hellyer S, Leach K, Gregory KJ. Neurobiological insights and novel therapeutic opportunities for CNS disorders from mGlu receptor allosteric and biased modulation. Curr Opin Pharmacol 2017; 32:49-55. [DOI: 10.1016/j.coph.2016.10.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 10/25/2016] [Accepted: 10/26/2016] [Indexed: 11/30/2022]
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Tomasetti C, Iasevoli F, Buonaguro EF, De Berardis D, Fornaro M, Fiengo ALC, Martinotti G, Orsolini L, Valchera A, Di Giannantonio M, de Bartolomeis A. Treating the Synapse in Major Psychiatric Disorders: The Role of Postsynaptic Density Network in Dopamine-Glutamate Interplay and Psychopharmacologic Drugs Molecular Actions. Int J Mol Sci 2017; 18:E135. [PMID: 28085108 PMCID: PMC5297768 DOI: 10.3390/ijms18010135] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Revised: 12/25/2016] [Accepted: 01/08/2017] [Indexed: 12/20/2022] Open
Abstract
Dopamine-glutamate interplay dysfunctions have been suggested as pathophysiological key determinants of major psychotic disorders, above all schizophrenia and mood disorders. For the most part, synaptic interactions between dopamine and glutamate signaling pathways take part in the postsynaptic density, a specialized ultrastructure localized under the membrane of glutamatergic excitatory synapses. Multiple proteins, with the role of adaptors, regulators, effectors, and scaffolds compose the postsynaptic density network. They form structural and functional crossroads where multiple signals, starting at membrane receptors, are received, elaborated, integrated, and routed to appropriate nuclear targets. Moreover, transductional pathways belonging to different receptors may be functionally interconnected through postsynaptic density molecules. Several studies have demonstrated that psychopharmacologic drugs may differentially affect the expression and function of postsynaptic genes and proteins, depending upon the peculiar receptor profile of each compound. Thus, through postsynaptic network modulation, these drugs may induce dopamine-glutamate synaptic remodeling, which is at the basis of their long-term physiologic effects. In this review, we will discuss the role of postsynaptic proteins in dopamine-glutamate signals integration, as well as the peculiar impact of different psychotropic drugs used in clinical practice on postsynaptic remodeling, thereby trying to point out the possible future molecular targets of "synapse-based" psychiatric therapeutic strategies.
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Affiliation(s)
- Carmine Tomasetti
- NHS, Department of Mental Health ASL Teramo, Psychiatric Service of Diagnosis and Treatment, Hospital "Maria SS dello Splendore", 641021 Giulianova, Italy.
- Laboratory of Molecular and Translational Psychiatry, Department of Neuroscience, Reproductive and Odontostomatogical Sciences, University of Naples "Federico II", 80131 Napoli, Italy.
- Polyedra Research Group, 64100 Teramo, Italy.
| | - Felice Iasevoli
- Laboratory of Molecular and Translational Psychiatry, Department of Neuroscience, Reproductive and Odontostomatogical Sciences, University of Naples "Federico II", 80131 Napoli, Italy.
- Polyedra Research Group, 64100 Teramo, Italy.
| | - Elisabetta Filomena Buonaguro
- Laboratory of Molecular and Translational Psychiatry, Department of Neuroscience, Reproductive and Odontostomatogical Sciences, University of Naples "Federico II", 80131 Napoli, Italy.
- Polyedra Research Group, 64100 Teramo, Italy.
| | - Domenico De Berardis
- Polyedra Research Group, 64100 Teramo, Italy.
- NHS, Department of Mental Health ASL Teramo, Psychiatric Service of Diagnosis and Treatment, Hospital "G. Mazzini", 64100 Teramo, Italy.
- Department of Neuroscience and Imaging, University "G. d'Annunzio", 66100 Chieti, Italy.
| | - Michele Fornaro
- Polyedra Research Group, 64100 Teramo, Italy.
- New York State Psychiatric Institute, Columbia University, New York, NY 10027, USA.
| | | | - Giovanni Martinotti
- Polyedra Research Group, 64100 Teramo, Italy.
- Department of Neuroscience and Imaging, University "G. d'Annunzio", 66100 Chieti, Italy.
| | - Laura Orsolini
- Polyedra Research Group, 64100 Teramo, Italy.
- Casa di Cura Villa San Giuseppe, 63100 Ascoli Piceno, Italy.
| | - Alessandro Valchera
- Polyedra Research Group, 64100 Teramo, Italy.
- Casa di Cura Villa San Giuseppe, 63100 Ascoli Piceno, Italy.
| | | | - Andrea de Bartolomeis
- Laboratory of Molecular and Translational Psychiatry, Department of Neuroscience, Reproductive and Odontostomatogical Sciences, University of Naples "Federico II", 80131 Napoli, Italy.
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Biased allosteric agonism and modulation of metabotropic glutamate receptor 5: Implications for optimizing preclinical neuroscience drug discovery. Neuropharmacology 2016; 115:60-72. [PMID: 27392634 DOI: 10.1016/j.neuropharm.2016.07.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 06/30/2016] [Accepted: 07/01/2016] [Indexed: 12/20/2022]
Abstract
Allosteric modulators, that exhibit no intrinsic agonist activity, offer the advantage of spatial and temporal fine-tuning of endogenous agonist activity, allowing the potential for increased selectivity, reduced adverse effects and improved clinical outcomes. Some allosteric ligands can differentially activate and/or modulate distinct signaling pathways arising from the same receptor, phenomena referred to as 'biased agonism' and 'biased modulation'. Emerging evidence for CNS disorders with glutamatergic dysfunction suggests the metabotropic glutamate receptor subtype 5 (mGlu5) is a promising target. Current mGlu5 allosteric modulators have largely been classified based on modulation of intracellular calcium (iCa2+) responses to orthosteric agonists alone. We assessed eight mGlu5 allosteric modulators previously classified as mGlu5 PAMs or PAM-agonists representing four distinct chemotypes across multiple measures of receptor activity, to explore their potential for engendering biased agonism and/or modulation. Relative to the reference orthosteric agonist, DHPG, the eight allosteric ligands exhibited distinct biased agonism fingerprints for iCa2+ mobilization, IP1 accumulation and ERK1/2 phosphorylation in HEK293A cells stably expressing mGlu5 and in cortical neuron cultures. VU0424465, DPFE and VU0409551 displayed the most disparate biased signaling fingerprints in both HEK293A cells and cortical neurons that may account for the marked differences observed previously for these ligands in vivo. Select mGlu5 allosteric ligands also showed 'probe dependence' with respect to their cooperativity with different orthosteric agonists, as well as biased modulation for the magnitude of positive cooperativity observed. Unappreciated biased agonism and modulation may contribute to unanticipated effects (both therapeutic and adverse) when translating from recombinant systems to preclinical models. This article is part of the Special Issue entitled 'Metabotropic Glutamate Receptors, 5 years on'.
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Litim N, Morissette M, Di Paolo T. Metabotropic glutamate receptors as therapeutic targets in Parkinson's disease: An update from the last 5 years of research. Neuropharmacology 2016; 115:166-179. [PMID: 27055772 DOI: 10.1016/j.neuropharm.2016.03.036] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 03/21/2016] [Accepted: 03/22/2016] [Indexed: 12/21/2022]
Abstract
Disturbance of glutamate neurotransmission in Parkinson's disease (PD) and l-DOPA induced dyskinesia (LID) is well documented. This review focuses on advances during the past five years on pharmacological modulation of metabotropic glutamate (mGlu) receptors in relation to anti-parkinsonian activity, LID attenuation, and neuroprotection. Drug design and characterization have led to the development of orthosteric agonists binding the same site as glutamate and Positive and Negative Allosteric modulators (PAMs and NAMs) binding sites different from the orthosteric site and offering subtype selectivity. Inhibition of group I (mGlu1 and mGlu5) receptors with NAMs and activation of group II (mGlu2 and 3 receptors) and group III (mGlu 4, 7 and 8 receptors) with PAMs and orthosteric agonists have shown their potential to inhibit glutamate release and attenuate excitotoxicity. Earlier and recent studies have led to the development of mGlu5 receptors NAMs to reduce LID and for neuroprotection, mGlu3 receptor agonists for neuroprotection while mGlu4 receptor PAMs and agonists for antiparkinsonian effects and neuroprotection. Furthermore, homo- and heterodimers of mGlu receptors are documented and highlight the complexity of the functioning of these receptors. Research on partial allosteric modulators and biased mGlu receptor allosteric modulators offer new glutamatergic drugs with better therapeutic effects and less off target adverse activity. Thus these various mGlu receptor targets will enable the development of novel drugs with improved clinical effects for normalization of glutamate transmission, treat PD and LID relief. This article is part of the Special Issue entitled 'Metabotropic Glutamate Receptors, 5 years on'.
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Affiliation(s)
- Nadhir Litim
- Neuroscience Research Unit, Centre Hospitalier Universitaire de Québec, CHUL, Quebec City, Canada; Faculty of Pharmacy, Laval University, Quebec City, Canada
| | - Marc Morissette
- Neuroscience Research Unit, Centre Hospitalier Universitaire de Québec, CHUL, Quebec City, Canada
| | - Thérèse Di Paolo
- Neuroscience Research Unit, Centre Hospitalier Universitaire de Québec, CHUL, Quebec City, Canada; Faculty of Pharmacy, Laval University, Quebec City, Canada.
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The NMDA Receptor and Schizophrenia: From Pathophysiology to Treatment. ADVANCES IN PHARMACOLOGY 2016; 76:351-82. [PMID: 27288082 DOI: 10.1016/bs.apha.2016.01.006] [Citation(s) in RCA: 181] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Schizophrenia is a severe mental illness that affects almost 1% of the population worldwide. Even though the etiology of schizophrenia is uncertain, it is believed to be a neurodevelopmental disorder that results from a combination of environmental insults and genetic vulnerabilities. Over the past 20 years, there has been a confluence of evidence from many research disciplines pointing to alterations in excitatory signaling, particularly involving hypofunction of the N-methyl-d-aspartate receptor (NMDAR), as a key contributor to the schizophrenia disease process. This review describes the structure-function relationship of the NMDAR channel and how the glycine modulatory site acts as an important regulator of its activity. In addition, this review highlights the genetic, pharmacologic, and biochemical evidence supporting the hypothesis that NMDAR hypofunction contributes to the pathophysiology of schizophrenia. Finally, this chapter highlights some of the most recent and promising pharmacological strategies that are designed to either, directly or indirectly, augment NMDAR function in an effort to treat the cognitive and negative symptoms of schizophrenia that are not helped by currently available medications.
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