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McCullock TW, Cardani LP, Kammermeier PJ. Signaling Specificity and Kinetics of the Human Metabotropic Glutamate Receptors. Mol Pharmacol 2024; 105:104-115. [PMID: 38164584 PMCID: PMC10794986 DOI: 10.1124/molpharm.123.000795] [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: 08/30/2023] [Revised: 10/13/2023] [Accepted: 11/08/2023] [Indexed: 01/03/2024] Open
Abstract
Metabotropic glutamate receptors (mGluRs) are obligate dimer G protein coupled receptors that can all function as homodimers. Here, each mGluR homodimer was examined for its G protein coupling profile using a bioluminescence resonance energy transfer-based assay that detects the interaction between a split YFP-tagged Gβ 1γ2 and a Nanoluciferase tagged free Gβγ sensor, MAS-GRK3-ct- nanoluciferase with 14 specific Gα proteins heterologously expressed, representing each family. Canonically, the group II and III mGluRs (2 and 3 and 4, 6, 7, and 8, respectively) are thought to couple to Gi/o exclusively. In addition, the group I mGluRs (1 and 5) are known to couple to the Gq/11 family and generally thought to also couple to the pertussis toxin-sensitive Gi/o family some reports have suggested Gs coupling is possible as cAMP elevations have been noted. In this study, coupling was observed with all eight mGluRs through the Gi/o proteins and only mGluR1 and mGluR5 through Gq/11, and, perhaps surprisingly, not G14 None activated any Gs protein. Interestingly, coupling was seen with the group I and II but not the group III mGluRs to G16 Slow but significant coupling to Gz was also seen with the group II receptors. SIGNIFICANCE STATEMENT: Metabotropic glutamate receptor (mGluR)-G protein coupling has not been thoroughly examined, and some controversy remains about whether some mGluRs can activate Gαs family members. Here we examine the ability of each mGluR to activate representative members of every Gα protein family. While all mGluRs can activate Gαi/o proteins, only the group I mGluRs couple to Gαq/11, and no members of the family can activate Gαs family members, including the group I receptors alone or with positive allosteric modulators.
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Affiliation(s)
- Tyler W McCullock
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York
| | - Loren P Cardani
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York
| | - Paul J Kammermeier
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York
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2
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McCullock TW, Cardani LP, Kammermeier PJ. Signaling specificity and kinetics of the human metabotropic glutamate receptors. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.24.550373. [PMID: 37546908 PMCID: PMC10402105 DOI: 10.1101/2023.07.24.550373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Metabotropic glutamate receptors (mGluRs) are obligate dimer G protein coupled receptors that can all function as homodimers. Here, each mGluR homodimer was examined for its G protein coupling profile using a BRET based assay that detects the interaction between a split YFP-tagged Gβ1γ2 and a Nanoluc tagged free Gβγ sensor, MAS-GRK3-ct-NLuc with 14 specific Ga proteins heterologously expressed, representing each family. Canonically, the group II and III mGluRs (2&3, and 4, 6, 7&8, respectively) are thought to couple to Gi/o exclusively. In addition, the group I mGluRs (1&5) are known to couple to the Gq/11 family, and generally thought to also couple to the PTX-sensitive Gi/o family; some reports have suggested Gs coupling is possible as cAMP elevations have been noted. In this study, coupling was observed with all 8 mGluRs through the Gi/o proteins, and only mGluR1&5 through Gq/11, and perhaps surprisingly, not G14. None activated any Gs protein. Interestingly, coupling was seen with the group I and II, but not the group III mGluRs to G16. Slow but significant coupling to Gz was also seen with the group II receptors.
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Affiliation(s)
- Tyler W. McCullock
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY 14642
| | - Loren P. Cardani
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY 14642
| | - Paul J. Kammermeier
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY 14642
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3
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Asch RH, Hillmer AT, Baldassarri SR, Esterlis I. The metabotropic glutamate receptor 5 as a biomarker for psychiatric disorders. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2023; 168:265-310. [PMID: 36868631 DOI: 10.1016/bs.irn.2022.10.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The role of glutamate system in the etiology and pathophysiology of psychiatric disorders has gained considerable attention in the past two decades, including dysregulation of the metabotropic glutamatergic receptor subtype 5 (mGlu5). Thus, mGlu5 may represent a promising therapeutic target for psychiatric conditions, particularly stress-related disorders. Here, we describe mGlu5 findings in mood disorders, anxiety, and trauma disorders, as well as substance use (specifically nicotine, cannabis, and alcohol use). We highlight insights gained from positron emission tomography (PET) studies, where possible, and discuss findings from treatment trials, when available, to explore the role of mGlu5 in these psychiatric disorders. Through the research evidence reviewed in this chapter, we make the argument that, not only is dysregulation of mGlu5 evident in numerous psychiatric disorders, potentially functioning as a disease "biomarker," the normalization of glutamate neurotransmission via changes in mGlu5 expression and/or modulation of mGlu5 signaling may be a needed component in treating some psychiatric disorders or symptoms. Finally, we hope to demonstrate the utility of PET as an important tool for investigating mGlu5 in disease mechanisms and treatment response.
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Affiliation(s)
- Ruth H Asch
- Department of Psychiatry, Yale University, New Haven, CT, United States.
| | - Ansel T Hillmer
- Department of Psychiatry, Yale University, New Haven, CT, United States; Department of Radiology and Biomedical Imaging, New Haven, CT, United States
| | - Stephen R Baldassarri
- Yale Program in Addiction Medicine, Yale University, New Haven, CT, United States; Department of Internal Medicine, Yale University, New Haven, CT, United States
| | - Irina Esterlis
- Department of Psychiatry, Yale University, New Haven, CT, United States; Department of Psychology, Yale University, New Haven, CT, United States; Clinical Neurosciences Division, U.S. Department of Veterans Affairs National Center for Posttraumatic Stress Disorder, Veterans Affairs Connecticut Healthcare System, West Haven, CT, United States
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4
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Zhuo B, Deng S, Li B, Zhu W, Zhang M, Qin C, Meng Z. Possible Effects of Acupuncture in Poststroke Aphasia. Behav Neurol 2023; 2023:9445381. [PMID: 37091130 PMCID: PMC10115536 DOI: 10.1155/2023/9445381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 12/30/2022] [Accepted: 04/02/2023] [Indexed: 04/25/2023] Open
Abstract
Neural plasticity promotes the reorganization of language networks and is an essential recovery mechanism for poststroke aphasia (PSA). Neuroplasticity may be a pivotal bridge to elucidate the potential recovery mechanisms of acupuncture for aphasia. Therefore, understanding the neuroplasticity mechanism of acupuncture in PSA is crucial. However, the underlying therapeutic mechanism of neuroplasticity in PSA after acupuncture needs to be explored. Excitotoxicity after brain injury affects the activity of neurotransmitters and disrupts the transmission of normal neuron information. Thus, a helpful strategy of acupuncture might be to improve PSA by affecting the availability of these neurotransmitters and glutamate receptors at synapses. In addition, the regulation of neuroplasticity by acupuncture may also be related to the regulation of astrocytes. Considering the guiding significance of acupuncture for clinical treatment, it is necessary to carry out further study about the influence of acupuncture on the recovery of aphasia after stroke. This study summarizes the current research on the neural mechanism of acupuncture in treating PSA. It seeks to elucidate the potential effect of acupuncture on the recovery of PSA from the perspective of synaptic plasticity and integrity of gray and white matter.
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Affiliation(s)
- Bifang Zhuo
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, China
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, China
| | - Shizhe Deng
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, China
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, China
| | - Boxuan Li
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, China
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, China
| | - Weiming Zhu
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, China
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, China
| | - Menglong Zhang
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, China
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, China
| | - Chenyang Qin
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, China
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, China
| | - Zhihong Meng
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, China
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, China
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5
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Abd-Elrahman KS, Ferguson SSG. Noncanonical Metabotropic Glutamate Receptor 5 Signaling in Alzheimer's Disease. Annu Rev Pharmacol Toxicol 2021; 62:235-254. [PMID: 34516293 DOI: 10.1146/annurev-pharmtox-021821-091747] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Metabotropic glutamate receptor 5 (mGluR5) is ubiquitously expressed in brain regions responsible for memory and learning. It plays a key role in modulating rapid changes in synaptic transmission and plasticity. mGluR5 supports long-term changes in synaptic strength by regulating the transcription and translation of essential synaptic proteins. β-Amyloid 42 (Aβ42) oligomers interact with a mGluR5/cellular prion protein (PrPC) complex to disrupt physiological mGluR5 signal transduction. Aberrant mGluR5 signaling and associated synaptic failure are considered an emerging pathophysiological mechanism of Alzheimer's disease (AD). Therefore, mGluR5 represents an attractive therapeutic target for AD, and recent studies continue to validate the efficacy of various mGluR5 allosteric modulators in improving memory deficits and mitigating disease pathology. However, sex-specific differences in the pharmacology of mGluR5 and activation of noncanonical signaling downstream of the receptor suggest that its utility as a therapeutic target in female AD patients needs to be reconsidered. Expected final online publication date for the Annual Review of Pharmacology and Toxicology, Volume 62 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Khaled S Abd-Elrahman
- University of Ottawa Brain and Mind Research Institute and Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada; .,Department of Pharmacology and Toxicology, Faculty of Pharmacy, Alexandria University, Alexandria 21521, Egypt; email
| | - Stephen S G Ferguson
- University of Ottawa Brain and Mind Research Institute and Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada;
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Dal Prà I, Armato U, Chiarini A. Family C G-Protein-Coupled Receptors in Alzheimer's Disease and Therapeutic Implications. Front Pharmacol 2019; 10:1282. [PMID: 31719824 PMCID: PMC6826475 DOI: 10.3389/fphar.2019.01282] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 10/07/2019] [Indexed: 12/12/2022] Open
Abstract
Alzheimer’s disease (AD), particularly its sporadic or late-onset form (SAD/LOAD), is the most prevalent (96–98% of cases) neurodegenerative dementia in aged people. AD’s neuropathology hallmarks are intrabrain accumulation of amyloid-β peptides (Aβs) and of hyperphosphorylated Tau (p-Tau) proteins, diffuse neuroinflammation, and progressive death of neurons and oligodendrocytes. Mounting evidences suggest that family C G-protein-coupled receptors (GPCRs), which include γ-aminobutyric acid B receptors (GABABRs), metabotropic glutamate receptors (mGluR1-8), and the calcium-sensing receptor (CaSR), are involved in many neurotransmitter systems that dysfunction in AD. This review updates the available knowledge about the roles of GPCRs, particularly but not exclusively those expressed by brain astrocytes, in SAD/LOAD onset and progression, taking stock of their respective mechanisms of action and of their potential as anti-AD therapeutic targets. In particular, GABABRs prevent Aβs synthesis and neuronal hyperexcitability and group I mGluRs play important pathogenetic roles in transgenic AD-model animals. Moreover, the specific binding of Aβs to the CaSRs of human cortical astrocytes and neurons cultured in vitro engenders a pathological signaling that crucially promotes the surplus synthesis and release of Aβs and hyperphosphorylated Tau proteins, and also of nitric oxide, vascular endothelial growth factor-A, and proinflammatory agents. Concurrently, Aβs•CaSR signaling hinders the release of soluble (s)APP-α peptide, a neurotrophic agent and GABABR1a agonist. Altogether these effects progressively kill human cortical neurons in vitro and likely also in vivo. Several CaSR’s negative allosteric modulators suppress all the noxious effects elicited by Aβs•CaSR signaling in human cortical astrocytes and neurons thus safeguarding neurons’ viability in vitro and raising hopes about their potential therapeutic benefits in AD patients. Further basic and clinical investigations on these hot topics are needed taking always heed that activation of the several brain family C GPCRs may elicit divergent upshots according to the models studied.
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Affiliation(s)
- Ilaria Dal Prà
- Human Histology and Embryology Unit, University of Verona Medical School, Verona, Italy
| | - Ubaldo Armato
- Human Histology and Embryology Unit, University of Verona Medical School, Verona, Italy
| | - Anna Chiarini
- Human Histology and Embryology Unit, University of Verona Medical School, Verona, Italy
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Mu B, Mu L, Schibli R, Ametamey SM, Milicevic Sephton S. Improved Syntheses of the mGlu5 Antagonists MMPEP and MTEP Using Sonogashira Cross-Coupling. Pharmaceuticals (Basel) 2018; 11:ph11010024. [PMID: 29461503 PMCID: PMC5874720 DOI: 10.3390/ph11010024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2017] [Revised: 02/10/2018] [Accepted: 02/12/2018] [Indexed: 11/16/2022] Open
Abstract
The Sonogashira cross-coupling, a key step in the syntheses of the mGlu5 antagonists MMPEP and MTEP, provided an improved three-step method for the preparation of MMPEP in 62% overall yield. Using Spartan molecular modeling kit an explanation for the failure to employ analogues method in the synthesis of MTEP was sought. The DFT calculations indicated that meaningful isolated yields were obtained when the HOMO energy of the aryl halide was lower than the HOMO energy of the respective alkyne.
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Affiliation(s)
- Boshuai Mu
- Center of Radiopharmaceutical Sciences of ETH, PSI and USZ, Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland.
| | - Linjing Mu
- Center of Radiopharmaceutical Sciences of ETH, PSI and USZ, Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland.
- Department of Nuclear Medicine, University Hospital Zurich, Ramistrasse 101, 8003 Zurich, Switzerland.
| | - Roger Schibli
- Center of Radiopharmaceutical Sciences of ETH, PSI and USZ, Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland.
- Department of Nuclear Medicine, University Hospital Zurich, Ramistrasse 101, 8003 Zurich, Switzerland.
| | - Simon M Ametamey
- Center of Radiopharmaceutical Sciences of ETH, PSI and USZ, Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland.
| | - Selena Milicevic Sephton
- Center of Radiopharmaceutical Sciences of ETH, PSI and USZ, Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland.
- Department of Nuclear Medicine, University Hospital Zurich, Ramistrasse 101, 8003 Zurich, Switzerland.
- Molecular Imaging Chemistry Laboratory, Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, University of Cambridge, Box 65 Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK..
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8
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Warnock G, Sommerauer M, Mu L, Pla Gonzalez G, Geistlich S, Treyer V, Schibli R, Buck A, Krämer SD, Ametamey SM. A first-in-man PET study of [ 18F]PSS232, a fluorinated ABP688 derivative for imaging metabotropic glutamate receptor subtype 5. Eur J Nucl Med Mol Imaging 2017; 45:1041-1051. [PMID: 29177707 DOI: 10.1007/s00259-017-3879-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2017] [Accepted: 11/06/2017] [Indexed: 12/21/2022]
Abstract
PURPOSE Non-invasive imaging of metabotropic glutamate receptor 5 (mGlu5) in the brain using PET is of interest in e.g., anxiety, depression, and Parkinson's disease. Widespread application of the most widely used mGlu5 tracer, [11C]ABP688, is limited by the short physical half-life of carbon-11. [18F]PSS232 is a fluorinated analog with promising preclinical properties and high selectivity and specificity for mGlu5. In this first-in-man study, we evaluated the brain uptake pattern and kinetics of [18F]PSS232 in healthy volunteers. METHODS [18F]PSS232 PET was performed with ten healthy male volunteers aged 20-40 years. Seven of the subjects received a bolus injection and the remainder a bolus/infusion protocol. Cerebral blood flow was determined in seven subjects using [15O]water PET. Arterial blood activity was measured using an online blood counter. Tracer kinetics were evaluated by compartment modeling and parametric maps were generated for both tracers. RESULTS At 90 min post-injection, 59.2 ± 11.1% of total radioactivity in plasma corresponded to intact tracer. The regional first pass extraction fraction of [18F]PSS232 ranged from 0.41 ± 0.06 to 0.55 ± 0.03 and brain distribution pattern matched that of [11C]ABP688. Uptake kinetics followed a simple two-tissue compartment model. The volume of distribution of total tracer (V T, ml/cm3) ranged from 1.18 ± 0.20 for white matter to 2.91 ± 0.51 for putamen. The respective mean distribution volume ratios (DVR) with cerebellum as the reference tissue were 0.88 ± 0.06 and 2.12 ± 0.10, respectively. The tissue/cerebellum ratios of a bolus/infusion protocol (30/70 dose ratio) were close to the DVR values. CONCLUSIONS Brain uptake of [18F]PSS232 matched the distribution of mGlu5 and followed a two-tissue compartment model. The well-defined kinetics and the possibility to use reference tissue models, obviating the need for arterial blood sampling, make [18F]PSS232 a promising fluorine-18 labeled radioligand for measuring mGlu5 density in humans.
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Affiliation(s)
- Geoffrey Warnock
- Department of Nuclear Medicine, University Hospital Zurich, 8091, Zurich, Switzerland
| | - Michael Sommerauer
- Department of Nuclear Medicine, University Hospital Zurich, 8091, Zurich, Switzerland.,Department of Neurology, University Hospital Zurich and University of Zurich, Zurich, Switzerland
| | - Linjing Mu
- Department of Nuclear Medicine, University Hospital Zurich, 8091, Zurich, Switzerland
| | - Gloria Pla Gonzalez
- Radiopharmaceutical Science, Institute of Pharmaceutical Sciences, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog Weg 4, 8093, Zurich, Switzerland
| | - Susanne Geistlich
- Radiopharmaceutical Science, Institute of Pharmaceutical Sciences, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog Weg 4, 8093, Zurich, Switzerland
| | - Valerie Treyer
- Department of Nuclear Medicine, University Hospital Zurich, 8091, Zurich, Switzerland
| | - Roger Schibli
- Radiopharmaceutical Science, Institute of Pharmaceutical Sciences, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog Weg 4, 8093, Zurich, Switzerland
| | - Alfred Buck
- Department of Nuclear Medicine, University Hospital Zurich, 8091, Zurich, Switzerland
| | - Stefanie D Krämer
- Radiopharmaceutical Science, Institute of Pharmaceutical Sciences, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog Weg 4, 8093, Zurich, Switzerland
| | - Simon M Ametamey
- Radiopharmaceutical Science, Institute of Pharmaceutical Sciences, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog Weg 4, 8093, Zurich, Switzerland.
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9
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Dindler A, Blaabjerg M, Kamand M, Bogetofte H, Meyer M. Activation of Group II Metabotropic Glutamate Receptors Increases Proliferation but does not Influence Neuronal Differentiation of a Human Neural Stem Cell Line. Basic Clin Pharmacol Toxicol 2017; 122:367-372. [PMID: 29024451 DOI: 10.1111/bcpt.12920] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 10/04/2017] [Indexed: 11/29/2022]
Abstract
The multiple functions of glutamate include regulation of neural development and stem cells. While the importance of the ionotropic glutamate receptors is well-established, less is known about the role of metabotropic glutamate receptors (mGluRs). In this study, we examined the effects of pharmacological activation and inhibition of mGluR2/3 on proliferation, differentiation and viability of a human neural stem cell line. Immunofluorescence staining revealed the presence of mGluR2/3 receptors on both proliferating and differentiating stem cells, including cells differentiated into β-tubulin III-positive immature neurons and glial fibrillary acidic protein-positive astrocytes. Stimulation of mGluR2/3 receptors during cell propagation using the agonist (2S,2'R,3'R)-2-(2',3'-dicarboxycyclopropyl) glycine (DCG-IV) increased total cell numbers significantly (60% compared to untreated controls). This effect could be inhibited by the specific antagonist (2S)-2-Amino-2-[(1S,2S)-2-carboxycycloprop-1-yl]-3-(xanth-9-yl) propanoic acid (LY341495). The antagonist alone had no effect. No significant decrease in cell death was found following mGluR2/3 stimulation, suggesting that the observed elevation in cell number was not related to cell viability. Subsequent differentiation of the cells resulted in a slight decrease in β-tubulin III-positive neurons (5.2-3.2% of total cells) for DCG-IV pre-treated cultures. Treatment with DCG-IV and LY342495 during cell differentiation alone had no such effect. Western blot analysis revealed that the active, dimeric form of mGluR2/3 was mainly present on the proliferating cells, which may explain our findings. This study emphasizes the importance of glutamate and mGluRs on regulation of human neural stem cells and suggests a significant role of mGluR2/3 during cell proliferation.
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Affiliation(s)
- Anne Dindler
- Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Morten Blaabjerg
- Department of Neurology, Odense University Hospital, Odense, Denmark.,Department of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Morad Kamand
- Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Helle Bogetofte
- Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Morten Meyer
- Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
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10
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The mGluR2 Positive Allosteric Modulator, AZD8529, and Cue-Induced Relapse to Alcohol Seeking in Rats. Neuropsychopharmacology 2016; 41:2932-2940. [PMID: 27339394 PMCID: PMC5061885 DOI: 10.1038/npp.2016.107] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 06/15/2016] [Accepted: 06/17/2016] [Indexed: 11/08/2022]
Abstract
Group II metabotropic glutamate receptors (mGluR2 and mGluR3) may control relapse of alcohol seeking, but previously available Group II agonists were unable to discriminate between mGluR2 and mGluR3. Here we use AZD8529, a novel positive allosteric mGluR2 modulator, to determine the role of this receptor for alcohol-related behaviors in rats. We assessed the effects of AZD8529 (20 and 40 mg/kg s.c.) on male Wistar rats trained to self-administer 20% alcohol and determined the effects of AZD8529 on self-administration, as well as stress-induced and cue-induced reinstatement of alcohol seeking. The on-target nature of findings was evaluated in Indiana P-rats, a line recently shown to carry a mutation that disrupts the gene encoding mGluR2. The behavioral specificity of AZD8529 was assessed using self-administration of 0.2% saccharin and locomotor activity tests. AZD8529 marginally decreased alcohol self-administration at doses that neither affected 0.2% saccharin self-administration nor locomotor activity. More importantly, cue- but not stress-induced alcohol seeking was blocked by the mGluR2 positive allosteric modulator. This effect of AZD8529 was completely absent in P rats lacking functional mGluR2s, demonstrating the receptor specificity of this effect. Our findings provide evidence for a causal role of mGluR2 in cue-induced relapse to alcohol seeking. They contribute support for the notion that positive allosteric modulators of mGluR2 block relapse-like behavior across different drug categories.
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11
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Zolotarev YA, Kovalev GI, Kost NV, Voevodina ME, Sokolov OY, Dadayan AK, Kondrakhin EA, Vasileva EV, Bogachuk AP, Azev VN, Lipkin VM, Myasoedov NF. Anxiolytic activity of the neuroprotective peptide HLDF-6 and its effects on brain neurotransmitter systems in BALB/c and C57BL/6 mice. J Psychopharmacol 2016; 30:922-35. [PMID: 27464742 DOI: 10.1177/0269881116660705] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
This study is focused on a new amide derivative of the peptide HLDF-6 (Thr-Gly-Glu-Asn-His-Arg). This hexapeptide is a fragment of Human Leukaemia Differentiation Factor (HLDF). It displays a broad range of nootropic and neuroprotective activities. We showed, for the first time, that the peptide HLDF-6-amide has high anxiolytic activity. We used 'open field' and 'elevated plus maze' tests to demonstrate anxiolytic effects of HLDF-6-amide (0.1 and 0.3 mg/kg intranasally), which were comparable to those of the reference drug diazepam (0.5 mg/kg). Five daily equipotent doses of HLDF-6-amide selectively mitigated anxiety and increased the density of NMDA receptors in the hippocampus of stress-susceptible BALB/c mice, and had no effect on stress-resilient C57BL/6 mice. The subchronic administration of HLDF-6-amide showed no effect on the density of GABAA and nicotine receptors but was accompanied by a nonselective decrease of the 5-HT2A serotonin receptor density in frontal cortex of both strains. The mechanism of the specific anxiolytic activity of HLDF-6-amide may include its action on the NMDA-glutamatergic receptor system of the hippocampus and on serotonin 5-HT2A-receptors in the prefrontal cortex. The psychotropic activity of HLDF-6-amide is promising for its introduction to medical practice as a highly effective anxiolytic medicine for mental and neurological diseases.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Anna P Bogachuk
- Shemyakin & Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia
| | - Vyacheslav N Azev
- Branch of Shemyakin & Ovchinnikov Institute of Bioorganic Chemistry, RAS, Pushchino, Moscow Region, Russia
| | - Valery M Lipkin
- Shemyakin & Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia
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12
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N-Alkylpyrido[1',2':1,5]pyrazolo-[4,3-d]pyrimidin-4-amines: A new series of negative allosteric modulators of mGlu1/5 with CNS exposure in rodents. Bioorg Med Chem Lett 2016; 26:1894-900. [PMID: 26988308 DOI: 10.1016/j.bmcl.2016.03.026] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 03/07/2016] [Accepted: 03/08/2016] [Indexed: 11/20/2022]
Abstract
Selective negative allosteric modulators (NAMs) of each of the group I metabotropic glutamate receptors (mGlu1 and mGlu5) have been well characterized in the literature and offer potential as therapeutics in several disorders of the central nervous system (CNS). Still, compounds that are potent mGlu1/5 NAMs with selectivity versus the other six members of the mGlu family as well as the balance of properties required for use in vivo are lacking. A medicinal chemistry effort centered on the identification of a lead series with the potential of delivering such compounds is described in this Letter. Specifically, a new class of pyrido[1',2':1,5]pyrazolo[4,3-d]pyrimidin-4-amines was designed as a novel isosteric replacement for 4-aminoquinazolines, and compounds from within this chemotype exhibited dual NAM activity at both group I mGlus. One compound, VU0467558 (29), demonstrated near equipotent activity at both receptors, selectivity versus other mGlus, a favorable ancillary pharmacology profile, and CNS exposure in rodents.
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13
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Synthesis and biological evaluation of picolinamides and thiazole-2-carboxamides as mGluR5 (metabotropic glutamate receptor 5) antagonists. Bioorg Med Chem Lett 2016; 26:140-4. [DOI: 10.1016/j.bmcl.2015.11.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2015] [Revised: 11/01/2015] [Accepted: 11/05/2015] [Indexed: 11/19/2022]
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Brownell AL, Kuruppu D, Kil KE, Jokivarsi K, Poutiainen P, Zhu A, Maxwell M. PET imaging studies show enhanced expression of mGluR5 and inflammatory response during progressive degeneration in ALS mouse model expressing SOD1-G93A gene. J Neuroinflammation 2015; 12:217. [PMID: 26597638 PMCID: PMC4657381 DOI: 10.1186/s12974-015-0439-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 11/18/2015] [Indexed: 12/11/2022] Open
Abstract
Background Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative motor neuron disorder. Genetic studies have linked mutation of the gene SOD1 to ALS pathology as well as several other pathological processes including modulation of glutamatergic function and inflammatory processes. Since therapeutic approaches for ALS are focused on glutamatergic function, we investigated modulation of glutamate transport based on its receptor function as well as excitotoxicity-induced inflammatory response. Methods In vivo positron emission tomography (PET) imaging studies of metabotropic glutamate receptor subtype 5 (mGluR5) using [18F]FPEB ([18F]3-fluoro-5-(2-pyridylethynyl)benzonitrile) and inflammatory response using [11C]PBR28 (peripheral benzodiazepine receptor ligand 28) were done in an early and a late phase of neurodegeneration in four ALS mice expressing SOD1-G93A gene and four control base mice (C57/BL6). Accumulation of [18F]FPEB and [11C]PBR28 were quantitated in several brain areas and spinal cord to determine degeneration-induced modulation. The studies were completed with immunohistochemical analyses of mGluR5 and inflammatory response. Results These studies showed enhanced binding potential of [18F]FPEB in several brain areas including striatum, hippocampus, and frontal cortex. In the whole brain, the binding potential increased 49 ± 9 % from base mice to ALS-type mice and further enhanced 23 ± 4 % during disease progression. Also, in the spinal cord 6–22 %, enhanced accumulation of [18F]FPEB was observed during progression of the disease. The accumulation of [11C]PBR28 increased by 110 ± 33 % in the whole brain during progression of the disease indicating significant inflammatory process. [11C]PBR28 accumulation enhanced 89–264 % in the spinal cord and 204 % in the lungs. The end point immunohistochemical analyses verified the enhanced mGluR5 expression and inflammation. Conclusions These results confirm the role of glutamate and inflammation in ALS-type pathology. These data also support the hypothesis that excessive glutamate may contribute to inflammation in the chronic neurodegenerative processes in ALS.
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Affiliation(s)
- Anna-Liisa Brownell
- Athinoula A Martinos Biomedical Imaging Center, Imaging, Massachusetts General Hospital, 149 13th Street, Charlestown, MA, USA.
| | - Darshini Kuruppu
- Department of Surgery, Massachusetts General Hospital, Charlestown, Massachusett, USA.
| | - Kun-Eek Kil
- Athinoula A Martinos Biomedical Imaging Center, Imaging, Massachusetts General Hospital, 149 13th Street, Charlestown, MA, USA.
| | - Kimmo Jokivarsi
- Athinoula A Martinos Biomedical Imaging Center, Imaging, Massachusetts General Hospital, 149 13th Street, Charlestown, MA, USA.
| | - Pekka Poutiainen
- Athinoula A Martinos Biomedical Imaging Center, Imaging, Massachusetts General Hospital, 149 13th Street, Charlestown, MA, USA.
| | - Aijun Zhu
- Athinoula A Martinos Biomedical Imaging Center, Imaging, Massachusetts General Hospital, 149 13th Street, Charlestown, MA, USA.
| | - Michelle Maxwell
- Department of Neurology, Massachusetts General Hospital, Charlestown, Massachusett, USA.
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Discovery and biological evaluation of tetrahydrothieno[2,3-c]pyridine derivatives as selective metabotropic glutamate receptor 1 antagonists for the potential treatment of neuropathic pain. Eur J Med Chem 2015; 97:245-58. [DOI: 10.1016/j.ejmech.2015.04.060] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 03/30/2015] [Accepted: 04/28/2015] [Indexed: 12/31/2022]
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16
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Cho GH, Kim T, Son WS, Seo SH, Min SJ, Cho YS, Keum G, Jeong KS, Koh HY, Lee J, Pae AN. Synthesis and biological evaluation of aryl isoxazole derivatives as metabotropic glutamate receptor 1 antagonists: A potential treatment for neuropathic pain. Bioorg Med Chem Lett 2015; 25:1324-8. [DOI: 10.1016/j.bmcl.2015.01.035] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 12/24/2014] [Accepted: 01/19/2015] [Indexed: 10/24/2022]
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17
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Erichsen JL, Blaabjerg M, Bogetofte H, Serrano AM, Meyer M. Group I Metabotropic Glutamate Receptors: A Potential Target for Regulation of Proliferation and Differentiation of an Immortalized Human Neural Stem Cell Line. Basic Clin Pharmacol Toxicol 2014; 116:329-36. [DOI: 10.1111/bcpt.12324] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2014] [Accepted: 09/03/2014] [Indexed: 11/28/2022]
Affiliation(s)
- Julie Ladeby Erichsen
- Department of Neurobiology Research; Institute of Molecular Medicine; University of Southern Denmark; Odense Denmark
| | - Morten Blaabjerg
- Department of Neurology; Odense University Hospital; Odense Denmark
| | - Helle Bogetofte
- Department of Neurobiology Research; Institute of Molecular Medicine; University of Southern Denmark; Odense Denmark
| | - Alberto Martinez Serrano
- Department of Molecular Biology and Center of Molecular Biology Severo Ochoa; University Autonoma Madrid-C.S.I.C. Campus Cantoblanco; Madrid Spain
| | - Morten Meyer
- Department of Neurobiology Research; Institute of Molecular Medicine; University of Southern Denmark; Odense Denmark
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18
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Doria JG, Silva FR, de Souza JM, Vieira LB, Carvalho TG, Reis HJ, Pereira GS, Dobransky T, Ribeiro FM. Metabotropic glutamate receptor 5 positive allosteric modulators are neuroprotective in a mouse model of Huntington's disease. Br J Pharmacol 2014; 169:909-21. [PMID: 23489026 PMCID: PMC3687670 DOI: 10.1111/bph.12164] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Revised: 12/31/2012] [Accepted: 02/17/2013] [Indexed: 11/29/2022] Open
Abstract
Background and Purpose Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder caused by a polyglutamine expansion in the huntingtin protein. We have previously demonstrated that the cell signalling of the metabotropic glutamate receptor 5 (mGluR5) is altered in a mouse model of HD. Although mGluR5-dependent protective pathways are more activated in HD neurons, intracellular Ca2+ release is also more pronounced, which could contribute to excitotoxicity. In the present study, we aim to investigate whether mGluR5 positive allosteric modulators (PAMs) could activate protective pathways without triggering high levels of Ca2+ release and be neuroprotective in HD. Experimental Approach We performed a neuronal cell death assay to determine which drugs are neuroprotective, Western blot and Ca2+ release experiments to investigate the molecular mechanisms involved in this neuroprotection, and object recognition task to determine whether the tested drugs could ameliorate HD memory deficit. Key Results We find that mGluR5 PAMs can protect striatal neurons from the excitotoxic neuronal cell death promoted by elevated concentrations of glutamate and NMDA. mGluR5 PAMs are capable of activating Akt without triggering increased intracellular Ca2+ concentration ([Ca2+]i); and Akt blockage leads to loss of PAM-mediated neuroprotection. Importantly, PAMs' potential as drugs that may be used to treat neurodegenerative diseases is highlighted by the neuroprotection exerted by mGluR5 PAMs on striatal neurons from a mouse model of HD, BACHD. Moreover, mGluR5 PAMs can activate neuroprotective pathways more robustly in BACHD mice and ameliorate HD memory deficit. Conclusions and Implications mGluR5 PAMs are potential drugs that may be used to treat neurodegenerative diseases, especially HD.
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Affiliation(s)
- J G Doria
- Departamento de Bioquimica e Imunologia, ICB, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
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19
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Sephton SM, Herde AM, Mu L, Keller C, Rüdisühli S, Auberson Y, Schibli R, Krämer SD, Ametamey SM. Preclinical evaluation and test-retest studies of [(18)F]PSS232, a novel radioligand for targeting metabotropic glutamate receptor 5 (mGlu5). Eur J Nucl Med Mol Imaging 2014; 42:128-37. [PMID: 25139517 DOI: 10.1007/s00259-014-2883-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 07/28/2014] [Indexed: 12/21/2022]
Abstract
PURPOSE A novel, (18)F-labelled metabotropic glutamate receptor subtype 5 (mGlu5) derivative of [(11)C]ABP688 ([(11)C]1), [(18)F]PSS232 ([(18)F] ]5), was evaluated in vitro and in vivo for its potential as a PET agent and was used in test-retest reliability studies METHODS The radiosynthesis of [(18)F]5 was accomplished via a one-step reaction using a mesylate precursor. In vitro stability was determined in PBS and plasma, and with liver microsomal enzymes. Metabolite studies were performed using rat brain extracts, blood and urine. In vitro autoradiography was performed on horizontal slices of rat brain using 1 and 8, antagonists for mGlu5 and mGlu1, respectively. Small-animal PET, biodistribution, and test-retest studies were performed in Wistar rats. In vivo, dose-dependent displacement studies were performed using 6 and blocking studies with 7. RESULTS [(18)F]5 was obtained in decay-corrected maximal radiochemical yield of 37 % with a specific activity of 80 - 400 GBq/μmol. Treatment with rat and human microsomal enzymes in vitro for 60 min resulted in 20 % and 4 % of hydrophilic radiometabolites, respectively. No hydrophilic decomposition products or radiometabolites were found in PBS or plasma. In vitro autoradiography on rat brain slices showed a heterogeneous distribution consistent with the known distribution of mGlu5 with high binding to hippocampal and cortical regions, and negligible radioactivity in the cerebellum. Similar distribution of radioactivity was found in PET images. Under displacement conditions with 6, reduced [(18)F]5 binding was found in all brain regions except the cerebellum. 7 reduced binding in the striatum by 84 % on average. Test-retest studies were reproducible with a variability ranging from 6.8 % to 8.2 %. An extended single-dose toxicity study in Wistar rats showed no compound-related adverse effects. CONCLUSION The new mGlu5 radiotracer, [(18)F]5, showed specific and selective in vitro and in vivo properties and is a promising radioligand for PET imaging of mGlu5 in humans.
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Affiliation(s)
- Selena Milicevic Sephton
- Center for Radiopharmaceutical Sciences of ETH, PSI and USZ, Vladimir-Prelog-Weg 4, 8093, Zurich, Switzerland
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20
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Zhou Y, Danbolt NC. Glutamate as a neurotransmitter in the healthy brain. J Neural Transm (Vienna) 2014; 121:799-817. [PMID: 24578174 PMCID: PMC4133642 DOI: 10.1007/s00702-014-1180-8] [Citation(s) in RCA: 527] [Impact Index Per Article: 52.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 02/11/2014] [Indexed: 12/13/2022]
Abstract
Glutamate is the most abundant free amino acid in the brain and is at the crossroad between multiple metabolic pathways. Considering this, it was a surprise to discover that glutamate has excitatory effects on nerve cells, and that it can excite cells to their death in a process now referred to as "excitotoxicity". This effect is due to glutamate receptors present on the surface of brain cells. Powerful uptake systems (glutamate transporters) prevent excessive activation of these receptors by continuously removing glutamate from the extracellular fluid in the brain. Further, the blood-brain barrier shields the brain from glutamate in the blood. The highest concentrations of glutamate are found in synaptic vesicles in nerve terminals from where it can be released by exocytosis. In fact, glutamate is the major excitatory neurotransmitter in the mammalian central nervous system. It took, however, a long time to realize that. The present review provides a brief historical description, gives a short overview of glutamate as a transmitter in the healthy brain, and comments on the so-called glutamate-glutamine cycle. The glutamate transporters responsible for the glutamate removal are described in some detail.
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Affiliation(s)
- Y. Zhou
- The Neurotransporter Group, Department of Anatomy, Institute of Basic Medical Sciences, University of Oslo, Blindern, P.O. Box 1105, 0317 Oslo, Norway
| | - N. C. Danbolt
- The Neurotransporter Group, Department of Anatomy, Institute of Basic Medical Sciences, University of Oslo, Blindern, P.O. Box 1105, 0317 Oslo, Norway
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21
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Bates BS, Rodriguez AL, Felts AS, Morrison RD, Venable DF, Blobaum AL, Byers FW, Lawson KP, Daniels JS, Niswender CM, Jones CK, Conn PJ, Lindsley CW, Emmitte KA. Discovery of VU0431316: a negative allosteric modulator of mGlu5 with activity in a mouse model of anxiety. Bioorg Med Chem Lett 2014; 24:3307-14. [PMID: 24969015 DOI: 10.1016/j.bmcl.2014.06.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 05/30/2014] [Accepted: 06/02/2014] [Indexed: 11/30/2022]
Abstract
Development of SAR in an aryl ether series of mGlu5 NAMs leading to the identification of pyrazine analog VU0431316 is described in this Letter. VU0431316 is a potent and selective non-competitive antagonist of mGlu5 that binds at a known allosteric binding site. VU0431316 demonstrates an attractive DMPK profile, including moderate clearance and good bioavailability in rats. Intraperitoneal (IP) dosing of VU0431316 in a mouse marble burying model of anxiety, an assay known to be sensitive to mGlu5 antagonists and other anxiolytics, produced dose proportional effects.
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Affiliation(s)
- Brittney S Bates
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Alice L Rodriguez
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Andrew S Felts
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Ryan D Morrison
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Daryl F Venable
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Anna L Blobaum
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Frank W Byers
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Kera P Lawson
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - J Scott Daniels
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Colleen M Niswender
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Carrie K Jones
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Tennessee Valley Healthcare System, U.S. Department of Veterans Affairs, Nashville, TN 37212, USA
| | - P Jeffrey Conn
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Craig W Lindsley
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Chemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - Kyle A Emmitte
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Chemistry, Vanderbilt University, Nashville, TN 37232, USA.
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22
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Abstract
Metabotropic glutamate receptors (mGluRs) are found throughout thalamus and cortex and are clearly important to circuit behavior in both structures, and so considering only participation of ionotropic glutamate receptors (e.g., [R,S]-α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid [AMPA] and N-methyl-d-aspartate receptors [NMDA] receptors) in glutamatergic processing would be an unfortunate oversimplification. These mGluRs are found both postsynaptically, on target cells of glutamatergic afferents, and presynaptically, on various synaptic terminals themselves, and when activated, they produce prolonged effects lasting at least hundreds of msec to several sec and perhaps longer. Two main types exist: activation of group I mGluRs causes postsynaptic depolarization, and group II, hyperpolarization. Both types are implicated in synaptic plasticity, both short term and long term. Their evident importance in functioning of thalamus and cortex makes it critical to develop a better understanding of how these receptors are normally activated, especially because they also seem implicated in a wide range of neurological and cognitive pathologies.
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23
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Williams CJ, Dexter DT. Neuroprotective and symptomatic effects of targeting group III mGlu receptors in neurodegenerative disease. J Neurochem 2013; 129:4-20. [PMID: 24224472 DOI: 10.1111/jnc.12608] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2013] [Revised: 10/28/2013] [Accepted: 11/06/2013] [Indexed: 12/21/2022]
Abstract
Neurodegenerative disorders possess common pathological mechanisms, such as protein aggregation, inflammation, oxidative stress (OS) and excitotoxicity, raising the possibility of shared therapeutic targets. As a result of the selective cellular and regional expression of group III metabotropic glutamate (mGlu) receptors, drugs targeting such receptors have demonstrated both neuroprotective properties and symptomatic improvements in several models of neurodegeneration. In recent years, the discovery and development of subtype-selective ligands for the group III mGlu receptors has gained pace, allowing further research into the functions of these receptors and revealing their roles in health and disease. Activation of this class of receptors results in neuroprotection, with a variety of underlying mechanisms implicated. Group III mGlu receptor stimulation prevents excitotoxicity by inhibiting glutamate release from neurons and microglia and increasing glutamate uptake by astrocytes. It also attenuates the neuroinflammatory response by reducing glial reactivity and encourages neurotrophic phenotypes. This article will review the current literature with regard to the neuroprotective and symptomatic effects of group III mGlu receptor activation and discuss their promise as therapeutic targets in neurodegenerative disease. We review the neuroprotective and symptomatic effects of targeting group III mGlu receptors in neurodegenerative disease: Excess extracellular glutamate causes overactivation of NMDA receptors resulting in excitotoxicity. Externalization of phosphatidylserine stimulates phagocytosis of neurons by activated microglia, which contribute to damage through glutamate and pro-inflammatory factor release. Reactive astrocytes produce cytotoxic factors enhancing neuronal cell death. Activation of group III mGlu receptors by glutamate and/or mGlu receptor ligands results in inhibition of glutamate release from presynaptic terminals and microglia, reducing excitotoxicity. Astrocytic glutamate uptake is increased and microglia produce neurotrophic factors.
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Affiliation(s)
- Claire J Williams
- Parkinson's Disease Research Group, Centre for Neuroinflammation and Neurodegeneration, Division of Brain Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, London, UK
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24
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Discovery of VU0409106: A negative allosteric modulator of mGlu5 with activity in a mouse model of anxiety. Bioorg Med Chem Lett 2013; 23:5779-85. [PMID: 24074843 DOI: 10.1016/j.bmcl.2013.09.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 08/30/2013] [Accepted: 09/03/2013] [Indexed: 02/06/2023]
Abstract
Development of SAR in an aryl ether series of mGlu5 NAMs leading to the identification of tool compound VU0409106 is described in this Letter. VU0409106 is a potent and selective negative allosteric modulator of mGlu5 that binds at the known allosteric binding site and demonstrates good CNS exposure following intraperitoneal dosing in mice. VU0409106 also proved efficacious in a mouse marble burying model of anxiety, an assay known to be sensitive to mGlu5 antagonists as well as clinically efficacious anxiolytics.
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25
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Amato RJ, Felts AS, Rodriguez AL, Venable DF, Morrison RD, Byers FW, Daniels JS, Niswender CM, Conn PJ, Lindsley CW, Jones CK, Emmitte KA. Substituted 1-Phenyl-3-(pyridin-2-yl)urea negative allosteric modulators of mGlu5: discovery of a new tool compound VU0463841 with activity in rat models of cocaine addiction. ACS Chem Neurosci 2013; 4:1217-28. [PMID: 23682684 DOI: 10.1021/cn400070k] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Cocaine is a powerful and highly addictive stimulant that disrupts the normal reward circuitry in the central nervous system (CNS), producing euphoric effects. Cocaine use can lead to acute and life threatening emergencies, and abuse is associated with increased risk for contracting infectious diseases. Though certain types of behavioral therapy have proven effective for treatment of cocaine addiction, relapse remains high, and there are currently no approved medications for the treatment of cocaine abuse. Evidence has continued to accumulate that indicates a critical role for the metabotropic glutamate receptor subtype 5 (mGlu5) in the modulation of neural circuitry associated with the addictive properties of cocaine. While the small molecule mGlu5 negative allosteric modulator (NAM) field is relatively advanced, investigation into the potential of small molecule mGlu5 NAMs for the treatment of cocaine addiction remains an area of high interest. Herein we describe the discovery and characterization of a potent and selective compound 29 (VU0463841) with good CNS exposure in rats. The utility of 29 (VU0463841) was demonstrated by its ability to attenuate drug seeking behaviors in relevant rat models of cocaine addiction.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Carrie K. Jones
- Tennessee
Valley Healthcare System, U.S. Department of Veterans Affairs, Nashville, Tennessee 37212, United States
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26
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Manka JT, Rodriguez AL, Morrison RD, Venable DF, Cho HP, Blobaum AL, Daniels JS, Niswender CM, Conn PJ, Lindsley CW, Emmitte KA. Octahydropyrrolo[3,4-c]pyrrole negative allosteric modulators of mGlu1. Bioorg Med Chem Lett 2013; 23:5091-6. [PMID: 23932792 DOI: 10.1016/j.bmcl.2013.07.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 07/03/2013] [Accepted: 07/16/2013] [Indexed: 11/29/2022]
Abstract
Development of SAR in an octahydropyrrolo[3,4-c]pyrrole series of negative allosteric modulators of mGlu1 using a functional cell-based assay is described in this Letter. The octahydropyrrolo[3,4-c]pyrrole scaffold was chosen as an isosteric replacement for the piperazine ring found in the initial hit compound. Characterization of selected compounds in protein binding assays was used to identify the most promising analogs, which were then profiled in P450 inhibition assays in order to further assess the potential for drug-likeness within this series of compounds.
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Affiliation(s)
- Jason T Manka
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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27
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Packiarajan M, Grenon M, Zorn S, Hopper AT, White AD, Chandrasena G, Pu X, Brodbeck RM, Robichaud AJ. Fused thiazolyl alkynes as potent mGlu5 receptor positive allosteric modulators. Bioorg Med Chem Lett 2013; 23:4037-43. [DOI: 10.1016/j.bmcl.2013.05.070] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 05/17/2013] [Accepted: 05/20/2013] [Indexed: 10/26/2022]
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28
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Lovell KM, Felts AS, Rodriguez AL, Venable DF, Cho HP, Morrison RD, Byers FW, Daniels JS, Niswender CM, Conn PJ, Lindsley CW, Emmitte KA. N-Acyl-N'-arylpiperazines as negative allosteric modulators of mGlu1: identification of VU0469650, a potent and selective tool compound with CNS exposure in rats. Bioorg Med Chem Lett 2013; 23:3713-8. [PMID: 23727046 DOI: 10.1016/j.bmcl.2013.05.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 04/29/2013] [Accepted: 05/07/2013] [Indexed: 12/12/2022]
Abstract
Development of SAR in an N-acyl-N'-arylpiperazine series of negative allosteric modulators of mGlu1 using a functional cell-based assay is described in this Letter. Characterization of selected compounds in protein binding assays was used to aid in selecting VU0469650 for further profiling in ancillary pharmacology assays and pharmacokinetic studies. VU0469650 demonstrated an excellent selectivity profile and good exposure in both plasma and brain samples following intraperitoneal dosing in rats.
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Affiliation(s)
- Kimberly M Lovell
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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Wang MJ, Li YC, Snyder MA, Wang H, Li F, Gao WJ. Group II metabotropic glutamate receptor agonist LY379268 regulates AMPA receptor trafficking in prefrontal cortical neurons. PLoS One 2013; 8:e61787. [PMID: 23593498 PMCID: PMC3625159 DOI: 10.1371/journal.pone.0061787] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Accepted: 03/13/2013] [Indexed: 12/26/2022] Open
Abstract
Group II metabotropic glutamate receptor (mGluR) agonists have emerged as potential treatment drugs for schizophrenia and other neurological disorders, whereas the mechanisms involved remain elusive. Here we examined the effects of LY379268 (LY37) on the expression and trafficking of the α-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptor subunits GluA1 and GluA2 in prefrontal neurons. We show that LY37 significantly increased the surface and total expression of both GluA1 and GluA2 subunits in cultured prefrontal neurons and in vivo. This effect was mimicked by the selective mGluR2 agonist LY395756 and was blocked by mGluR2/3 antagonist LY341495. Moreover, we found that both GluA1 and GluA2 subunits were colocalized with PSD95 but not synapsin I, suggesting a postsynaptic localization. Consistently, treatment with LY37 significantly increased the amplitude, but not frequency, of miniature excitatory postsynaptic currents. Further, actinomycin-D blocked LY37's effects, suggesting a transcriptional regulation. In addition, application of glycogen synthase kinase-3beta (GSK-3β) inhibitor completely blocked LY37's effect on GluA2 surface expression, whereas GSK-3β inhibitor itself induced decreases in the surface and total protein levels of GluA1, but not GluA2 subunits. This suggests that GSK-3β differentially mediates GluA1 and GluA2 trafficking. Further, LY37 significantly increased the phosphorylation, but not total protein, of extracellular signal-regulated kinase 1/2 (ERK1/2). Neither ERK1/2 inhibitor PD98059 alone nor PD98059 combined with LY37 treatment induced changes in GluA1 or GluA2 surface expression or total protein levels. Our data thus suggest that mGluR2/3 agonist regulates postsynaptic AMPA receptors by affecting the synaptic trafficking of both GluA1 and GluA2 subunits and that the regulation is likely through ERK1/2 signaling in GluA1 and/or both ERK1/2 and GSK-3β signaling pathways in the GluA2 subunit.
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Affiliation(s)
- Min-Juan Wang
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
- Department of Neurobiology and Anatomy, Zhongshan College of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Yan-Chun Li
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Melissa A. Snyder
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Huaixing Wang
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Feng Li
- Department of Neurobiology and Anatomy, Zhongshan College of Medicine, Sun Yat-Sen University, Guangzhou, China
- * E-mail: (WJG); (FL)
| | - Wen-Jun Gao
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
- * E-mail: (WJG); (FL)
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Son MH, Kim JY, Lim EJ, Baek DJ, Choi K, Lee JK, Pae AN, Min SJ, Cho YS. Synthesis and biological evaluation of 2-(arylethynyl)quinoline derivatives as mGluR5 antagonists for the treatment of neuropathic pain. Bioorg Med Chem Lett 2013; 23:1472-6. [DOI: 10.1016/j.bmcl.2012.12.056] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Revised: 12/13/2012] [Accepted: 12/15/2012] [Indexed: 10/27/2022]
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Abstract
INTRODUCTION The design and development of small molecule negative allosteric modulators (NAMs) of the metabotropic glutamate receptor subtype 5 (mGlu5) has been an area of intense interest for over a decade. Potential roles have been established for mGlu5 NAMs in the treatment of diseases such as pain, anxiety, gastroesophageal reflux disease (GERD), Parkinson's disease levodopa-induced dyskinesia (PD-LID), fragile X syndrome (FXS), autism, addiction, and depression. AREAS COVERED This review begins with an update of the clinical trial efforts with mGlu5 NAMs. Following that update, the review summarizes small molecule mGlu5 NAM patent applications published between 2010 and 2012. These summaries are subdivided into three separate groups: inventions related to improvements in drug properties and/or developability, new chemical entities that contain a disubstituted alkyne, and new chemical entities that do not contain a disubstituted alkyne. EXPERT OPINION Given the abundant promise found within the mGlu5 NAM field, optimism remains that a drug will emerge from this therapeutic class. Still, the launch of a new drug is far from a certainty. It is encouraging to observe the ever-increasing chemical diversity among mGlu5 NAMs. Finally, in spite of the mature nature of this field, room remains for new advancements.
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Affiliation(s)
- Kyle A Emmitte
- Vanderbilt University Medical Center, Vanderbilt Center for Neuroscience Drug Discovery, Department of Chemistry, Nashville, TN 37232, USA.
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Sephton SM, Mu L, Müller A, Wanger-Baumann CA, Schibli R, Krämer SD, Ametamey SM. Synthesis and in vitro/in vivo pharmacological evaluation of [11C]-ThioABP, a novel radiotracer for imaging mGluR5 with PET. MEDCHEMCOMM 2013. [DOI: 10.1039/c2md20332d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Packiarajan M, Ferreira CGM, Hong SP, White AD, Chandrasena G, Pu X, Brodbeck RM, Robichaud AJ. Azetidinyl oxadiazoles as potent mGluR5 positive allosteric modulators. Bioorg Med Chem Lett 2012; 22:6469-74. [PMID: 22975301 DOI: 10.1016/j.bmcl.2012.08.044] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 08/02/2012] [Accepted: 08/13/2012] [Indexed: 12/15/2022]
Abstract
A novel series of aryl azetidinyl oxadiazoles are identified as mGluR5 positive allosteric modulators (PAMs) with improved physico-chemical properties. N-substituted cyclohexyl and exo-norbornyl carboxamides, and carbamate analogs of azetidines are moderate to potent mGluR5 PAMs. The aryl, lower alkyl carboxamides analogs and sulfonamide analogs of azetidines are moderate mGluR5 negative allosteric modulators (NAMs). In the aryl oxadiazole moiety, substituents such as fluoro, chloro and methyl are well tolerated at the meta position while para substituents led to either inactive compounds or NAMs. A tight pharmacophore and subtle 'PAM to NAM switching' with close analogs makes the optimization of the series extremely challenging.
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Gabriel L, Lvov A, Orthodoxou D, Rittenhouse AR, Kobertz WR, Melikian HE. The acid-sensitive, anesthetic-activated potassium leak channel, KCNK3, is regulated by 14-3-3β-dependent, protein kinase C (PKC)-mediated endocytic trafficking. J Biol Chem 2012; 287:32354-66. [PMID: 22846993 DOI: 10.1074/jbc.m112.391458] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The acid-sensitive neuronal potassium leak channel, KCNK3, is vital for setting the resting membrane potential and is the primary target for volatile anesthetics. Recent reports demonstrate that KCNK3 activity is down-regulated by PKC; however, the mechanisms responsible for PKC-induced KCNK3 down-regulation are undefined. Here, we report that endocytic trafficking dynamically regulates KCNK3 activity. Phorbol esters and Group I metabotropic glutamate receptor (mGluR) activation acutely decreased both native and recombinant KCNK3 currents with concomitant KCNK3 surface losses in cerebellar granule neurons and cell lines. PKC-mediated KCNK3 internalization required the presence of both 14-3-3β and a novel potassium channel endocytic motif, because depleting either 14-3-3β protein levels or ablating the endocytic motif completely abrogated PKC-regulated KCNK3 trafficking. These results demonstrate that neuronal potassium leak channels are not static membrane residents but are subject to 14-3-3β-dependent regulated trafficking, providing a straightforward mechanism to modulate neuronal excitability and synaptic plasticity by Group I mGluRs.
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Affiliation(s)
- Luke Gabriel
- Graduate Program in Neuroscience, University of Massachusetts Medical School, Worcester, Massachusetts 01604, USA
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Packiarajan M, Mazza Ferreira CG, Hong SP, White AD, Chandrasena G, Pu X, Brodbeck RM, Robichaud AJ. N-Aryl pyrrolidinonyl oxadiazoles as potent mGluR5 positive allosteric modulators. Bioorg Med Chem Lett 2012; 22:5658-62. [PMID: 22832311 DOI: 10.1016/j.bmcl.2012.06.094] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Revised: 06/26/2012] [Accepted: 06/27/2012] [Indexed: 10/28/2022]
Abstract
A novel series of N-aryl pyrrolidinonyl oxadiazoles were identified as mGluR5 positive allosteric modulators (PAMs). Optimization of the initial lead compound 6a led to the identification of the 12c (-) enantiomer as a potent compound with acceptable in vitro clearance, CYP, hERG and PK properties. Para substituted N-aryl pyrrolidinonyl oxadiazoles are mGluR5 PAMs while the meta and ortho substituted N-aryl pyrrolidinonyl oxadiazoles are negative allosteric modulators (NAMs). Para fluoro substitution on the N-aryl group and meta chloro or methyl substituents on the aryl oxadiazole moiety are optimal for mGluR5 PAM efficacy. The existence of an exquisitely sensitive 'PAM to NAM switch' within this chemotype making it challenging for simultaneous optimization of potency and drug-like properties.
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Affiliation(s)
- Mathivanan Packiarajan
- Chemical & Pharmacokinetic Sciences, Lundbeck Research USA, 215 College Road, Paramus, NJ 07652, USA.
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Ago Y, Araki R, Yano K, Hiramatsu N, Kawasaki T, Chaki S, Nakazato A, Onoe H, Hashimoto H, Baba A, Takuma K, Matsuda T. Activation of metabotropic glutamate 2/3 receptors attenuates methamphetamine-induced hyperlocomotion and increase in prefrontal serotonergic neurotransmission. Psychopharmacology (Berl) 2011; 217:443-52. [PMID: 21487651 DOI: 10.1007/s00213-011-2295-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2010] [Accepted: 04/01/2011] [Indexed: 12/25/2022]
Abstract
RATIONALE Metabotropic glutamate (mGlu) 2/3 receptor agonists inhibit amphetamine- and phencyclidine-induced hyperlocomotion. The mechanism for the antipsychotic effect of mGlu2/3 receptor agonists was studied in a hypoglutamatergic model, but not a hyperdopaminergic model. OBJECTIVES To study the mechanism for the antipsychotic effect of the agonist in the hyperdopaminergic model, this study examined the effects of the selective mGlu2/3 receptor agonist MGS0028 on methamphetamine-induced hyperlocomotion and the increases in extracellular levels of serotonin, dopamine, noradrenaline, and glutamate in the prefrontal cortex and nucleus accumbens of mice. RESULTS Systemic administration of MGS0028 attenuated methamphetamine-induced hyperlocomotion in a dose-dependent manner. Microdialysis studies showed that MGS0028 significantly inhibited methamphetamine-induced increases in the extracellular serotonin, but not dopamine and noradrenaline, levels in the prefrontal cortex, and it did not affect methamphetamine-induced increases in the extracellular amine levels in the nucleus accumbens. Methamphetamine did not affect the glutamate release in the prefrontal cortex and nucleus accumbens. Local application of MGS0028 into the prefrontal cortex also attenuated methamphetamine-induced hyperlocomotion and increases in the extracellular serotonin levels in the prefrontal cortex. Moreover, MGS0028 did not affect methamphetamine-induced hyperlocomotion in the mice pretreated with p-chlorophenylalanine, a serotonin synthesis inhibitor. CONCLUSIONS Activation of prefrontal mGlu2/3 receptors inhibits the psychomotor stimulant effect of methamphetamine in mice, and the prefrontal serotonergic system may be involved in this effect. The finding provides evidence that prefrontal mGlu2/3 receptors are functionally coupled with the serotonergic system.
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Affiliation(s)
- Yukio Ago
- Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka, 565-0871, Japan
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Zhu JW, Yuan JF, Yang HM, Wang ST, Zhang CG, Sun LL, Yang H, Zhang H. Extracellular cysteine (Cys)/cystine (CySS) redox regulates metabotropic glutamate receptor 5 activity. Biochimie 2011; 94:617-27. [PMID: 21964032 DOI: 10.1016/j.biochi.2011.09.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Accepted: 09/15/2011] [Indexed: 01/12/2023]
Abstract
Extracellular cysteine (Cys)/cystine (CySS) redox potential (E(h)) has been shown to regulate diverse biological processes, including enzyme catalysis, gene expression, and signaling pathways for cell proliferation and apoptosis, and is sensitive to aging, smoking, and other host factors. However, the effects of extracellular Cys/CySS redox on the nervous system remain unknown. In this study, we explored the role of extracellular Cys/CySS E(h) in metabotropic glutamate receptor 5 (mGlu5) activation to understand the mechanism of its regulation of nerve cell growth and activation. We showed that the oxidized Cys/CySS redox state (0 mV) in C6 glial cells induced a significant increase in mGlu5-mediated phosphorylation of extracellular signal-regulated kinase (ERK), blocked by an inhibitor of mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (MEK), U0126, a nonpermeant alkylating agent, 4-acetamide-4'-maleimidylstilbene-2,2'-disulfonic acid (AMS), and a specific mGlu5 antagonist, 2-methyl-6-(phenylethynyl)pyridine (MPEP), respectively. ERK phosphorylation under oxidized extracellular Cys/CySS E(h) was confirmed in mGlu5-overexpressed human embryonic kidney 293 (HEK293) cells. Oxidized extracellular Cys/CySS E(h) also stimulated the generation of intracellular reactive oxygen species (ROS) involved in the phosphorylation of ERK by mGlu5. Moreover, activation of mGlu5 by oxidized extracellular Cys/CySS E(h) was found to affect expression of NF-κB and inducible nitric oxide synthase (iNOS). The results also showed that extracellular Cys/CySS E(h) involved in the activation of mGlu5 controlled cell death and cell activation in neurotoxicity. In addition, plasma Cys/CySS E(h) was found to be associated with the process of Parkinson's disease (PD) in a rotenone-induced rat model of PD together with dietary deficiency and supplementation of sulfur amino acid (SAA). The effects of extracellular Cys/CySS E(h) on SAA dietary deficiency in the rotenone-induced rat model of PD was almost blocked by MPEP pretreatment, further indicating that oxidized extracellular Cys/CySS E(h) plays a role in mGlu5 activity. Taken together, the results indicate that mGlu5 can be activated by extracellular Cys/CySS redox in nerve cells, which possibly contributes to the process of PD. These in vitro and in vivo findings may aid in the development of potential new nutritional strategies that could assist in slowing the degeneration of PD.
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Affiliation(s)
- Jia Wei Zhu
- Department of Cell Biology, Capital Medical University, Beijing 100069, China
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Differential effect of the mGlu5 receptor positive allosteric modulator ADX-47273 on early and late hippocampal LTP. Neuropharmacology 2011; 61:707-14. [DOI: 10.1016/j.neuropharm.2011.05.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Revised: 02/28/2011] [Accepted: 05/17/2011] [Indexed: 11/23/2022]
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Lindsley CW, Bates BS, Menon UN, Jadhav SB, Kane AS, Jones CK, Rodriguez AL, Conn PJ, Olsen CM, Winder DG, Emmitte KA. (3-Cyano-5-fluorophenyl)biaryl negative allosteric modulators of mGlu(5): Discovery of a new tool compound with activity in the OSS mouse model of addiction. ACS Chem Neurosci 2011; 2:471-482. [PMID: 21927650 DOI: 10.1021/cn100099n] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Glutamate is the major excitatory transmitter in the mammalian CNS, exerting its effects through both ionotropic and metabotropic glutamate receptors. The metabotropic glutamate receptors (mGlus) belong to family C of the G-protein-coupled receptors (GPCRs). The eight mGlus identified to date are classified into three groups based on their structure, preferred signal transduction mechanisms, and pharmacology (Group I: mGlu(1) and mGlu(5); Group II: mGlu(2) and mGlu(3); Group III: mGlu(4), mGlu(6), mGlu(7), and mGlu(8)). Non-competitive antagonists, also known as negative allosteric modulators (NAMs), of mGlu(5) offer potential therapeutic applications in diseases such as pain, anxiety, gastroesophageal reflux disease (GERD), Parkinson's disease (PD), fragile X syndrome, and addiction. The development of SAR in a (3-cyano-5-fluorophenyl)biaryl series using our functional cell-based assay is described in this communication. Further characterization of a selected compound, 3-fluoro-5-(2-methylbenzo[d]thiazol-5-yl)benzonitrile, in additional cell based assays as well as in vitro assays designed to measure its metabolic stability and protein binding indicated its potential utility as an in vivo tool. Subsequent evaluation of the same compound in a pharmacokinetic study using intraperitoneal dosing in mice showed good exposure in both plasma and brain samples. The compound was efficacious in a mouse marble burying model of anxiety, an assay known to be sensitive to mGlu(5) antagonists. A new operant model of addiction termed operant sensation seeking (OSS) was chosen as a second behavioral assay. The compound also proved efficacious in the OSS model and constitutes the first reported example of efficacy with a small molecule mGlu(5) NAM in this novel assay.
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Affiliation(s)
| | | | | | | | | | - Carrie K. Jones
- Tennesse Valley Healthcare System, U.S. Department of Veterans Affairs, Nashville, Tennessee 37212, United States
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Emmitte KA. Recent advances in the design and development of novel negative allosteric modulators of mGlu(5). ACS Chem Neurosci 2011; 2:411-432. [PMID: 21927649 DOI: 10.1021/cn2000266] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Negative allosteric modulators (NAMs) of metabotropic glutamate receptor subtype 5 (mGlu(5)) have remained attractive to researchers as potential therapies for a number of central nervous system related diseases, including anxiety, pain, gastroesophageal reflux disease (GERD), addiction, Parkinson's disease (PD), and fragile X syndrome (FXS). In addition to the many publications with supportive preclinical data with key tool molecules, recent positive reports from the clinic have bolstered the confidence in this approach. During the two year time span from 2009 through 2010, a number of new mGlu(5) NAM chemotypes have been disclosed and discussed in the primary and patent literature. A summary of several efforts representing many diverse chemotypes are presented here, along with a discussion of representative structure activity relationships (SAR) and synthetic approaches to the templates where possible.
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Affiliation(s)
- Kyle A. Emmitte
- Department of Pharmacology, Vanderbilt Center for Neuroscience Drug Discovery, and Department of Chemistry, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
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Weiss JM, Jimenez HN, Li G, April M, Uberti MA, Bacolod MD, Brodbeck RM, Doller D. 6-Aryl-3-pyrrolidinylpyridines as mGlu5 receptor negative allosteric modulators. Bioorg Med Chem Lett 2011; 21:4891-9. [DOI: 10.1016/j.bmcl.2011.06.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Revised: 06/03/2011] [Accepted: 06/06/2011] [Indexed: 11/25/2022]
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In vitro and in vivo evaluation of [18F]-FDEGPECO as a PET tracer for imaging the metabotropic glutamate receptor subtype 5 (mGluR5). Neuroimage 2011; 56:984-91. [DOI: 10.1016/j.neuroimage.2011.03.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Revised: 03/03/2011] [Accepted: 03/08/2011] [Indexed: 11/19/2022] Open
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Riaza Bermudo-Soriano C, Perez-Rodriguez MM, Vaquero-Lorenzo C, Baca-Garcia E. New perspectives in glutamate and anxiety. Pharmacol Biochem Behav 2011; 100:752-74. [PMID: 21569789 DOI: 10.1016/j.pbb.2011.04.010] [Citation(s) in RCA: 146] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Revised: 04/05/2011] [Accepted: 04/15/2011] [Indexed: 02/07/2023]
Abstract
Anxiety and stress-related disorders, namely posttraumatic stress disorder (PTSD), generalized anxiety disorder (GAD), obsessive-compulsive disorder (ODC), social and specific phobias, and panic disorder, are a major public health issue. A growing body of evidence suggests that glutamatergic neurotransmission may be involved in the biological mechanisms underlying stress response and anxiety-related disorders. The glutamatergic system mediates the acquisition and extinction of fear-conditioning. Thus, new drugs targeting glutamatergic neurotransmission may be promising candidates for new pharmacological treatments. In particular, N-methyl-d-aspartate receptors (NMDAR) antagonists (AP5, AP7, CGP37849, CGP39551, LY235959, NPC17742, and MK-801), NMDAR partial agonists (DCS, ACPC), α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate receptors (AMPARs) antagonists (topiramate), and several allosteric modulators targeting metabotropic glutamate receptors (mGluRs) mGluR1, mGluR2/3, and mGluR5, have shown anxiolytic-like effects in several animal and human studies. Several studies have suggested that polyamines (agmatine, putrescine, spermidine, and spermine) may be involved in the neurobiological mechanisms underlying stress-response and anxiety-related disorders. This could mainly be attributed to their ability to modulate ionotropic glutamate receptors, especially NR2B subunits. The aim of this review is to establish that glutamate neurotransmission and polyaminergic system play a fundamental role in the onset of anxiety-related disorders. This may open the way for new drugs that may help to treat these conditions.
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Positive allosteric modulators of type 5 metabotropic glutamate receptors (mGluR5) and their therapeutic potential for the treatment of CNS disorders. Molecules 2011; 16:2097-106. [PMID: 21368721 PMCID: PMC3070661 DOI: 10.3390/molecules16032097] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Revised: 02/08/2011] [Accepted: 02/28/2011] [Indexed: 01/12/2023] Open
Abstract
Studies utilizing selective pharmacological antagonists or targeted gene deletion have demonstrated that type 5 metabotropic glutamate receptors (mGluR5) are critical mediators and potential therapeutic targets for the treatment of numerous disorders of the central nervous system (CNS), including depression, anxiety, drug addiction, chronic pain, Fragile X syndrome, Parkinson’s disease, and gastroesophageal reflux disease. However, in recent years, the development of positive allosteric modulators (PAMs) of the mGluR5 receptor have revealed that allosteric activation of this receptor may also be of potential therapeutic benefit for the treatment of other CNS disorders, including schizophrenia, cognitive deficits associated with chronic drug use, and deficits in extinction learning. Here we summarize the discovery and characterization of various mGluR5 PAMs, with an emphasis on those that are systemically active. We will also review animal studies showing that these molecules have potential efficacy as novel antipsychotic agents. Finally, we will summarize findings that suggest that mGluR5 PAMs have pro-cognitive effects such as the ability to enhance synaptic plasticity, improve performance in various learning and memory tasks, including extinction of drug-seeking behavior, and reverse cognitive deficits produced by chronic drug use.
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Haas HS, Linecker A, Pfragner R, Sadjak A. Peripheral glutamate signaling in head and neck areas. Head Neck 2011; 32:1554-72. [PMID: 20848447 DOI: 10.1002/hed.21438] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The major excitatory neurotransmitter glutamate is also found in the periphery in an increasing number of nonexcitable cells. In line with this it became apparent that glutamate can regulate a broad array of peripheral biological responses, as well. Of particular interest is the discovery that glutamate receptor reactive reagents can influence tumor biology. However, the knowledge of glutamate signaling in peripheral tissues is still incomplete and, in the case of head and neck areas, is almost lacking. The roles of glutamate signaling pathways in these regions are manifold and include orofacial pain, periodontal bone production, skin and airway inflammation, as well as salivation. Furthermore, the interrelations between glutamate and cancers in the oral cavity, thyroid gland, and other regions are discussed. In summary, this review shall strengthen the view that glutamate receptor reagents may also be promising targets for novel therapeutic concepts suitable for a number of diseases in peripheral tissues. The contents of this review cover the following sections: Introduction; The "Glutamate System"; The Taste of Glutamate; Glutamate Signaling in Dental Regions; Glutamate Signaling in Head and Neck Areas; Glutamate Signaling in Head and Neck Cancer; A Brief Overview of Glutamate Signaling in Other Cancers; and Conclusion.
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Affiliation(s)
- Helga Susanne Haas
- Department of Pathophysiology and Immunology, Center of Molecular Medicine, Medical University of Graz, Graz, Austria.
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DeLorenzo C, Milak MS, Brennan KG, Kumar JSD, Mann JJ, Parsey RV. In vivo positron emission tomography imaging with [¹¹C]ABP688: binding variability and specificity for the metabotropic glutamate receptor subtype 5 in baboons. Eur J Nucl Med Mol Imaging 2011; 38:1083-94. [PMID: 21279350 DOI: 10.1007/s00259-010-1723-7] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Accepted: 12/17/2010] [Indexed: 11/30/2022]
Abstract
PURPOSE Metabotropic glutamate receptor subtype 5 (mGluR5) dysfunction has been implicated in several disorders. [(11)C]ABP688, a positron emission tomography (PET) ligand targeting mGluR5, could be a valuable tool in the development of novel therapeutics for these disorders by establishing in vivo drug occupancy. Due to safety concerns in humans, these studies may be performed in nonhuman primates. Therefore, in vivo characterization of [(11)C]ABP688 in nonhuman primates is essential. METHODS Test-retest studies were performed in baboons (Papio anubis) to compare modeling approaches and determine the optimal reference region. The mGluR5-specific antagonist 3-((2-methyl-1,3-thiazol-4-yl)ethynyl)pyridine (MTEP) was then used in test-block studies, in which ligand binding was measured before and after MTEP administration. Test/block data were analyzed both by calculating changes in binding and using a graphical approach, which allowed estimation of both MTEP occupancy and nonspecific binding. RESULTS Test-retest results, which have not been previously reported for [(11)C]ABP688, indicated that [(11)C]ABP688 variability is low using an unconstrained two-tissue compartment model. The most appropriate, though not ideal, reference region was found to be the gray matter of the cerebellum. Using these optimal modeling techniques on the test/block data, about 90% occupancy was estimated by the graphical approach. CONCLUSION These studies are the first to demonstrate the specificity of [(11)C]ABP688 for mGluR5 with in vivo PET in nonhuman primates. The results indicate that, in baboons, occupancy of mGluR5 is detectable by in vivo PET, a useful finding for proceeding to human studies, or performing further baboon studies, quantifying the in vivo occupancy of novel therapeutics targeting mGluR5.
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Affiliation(s)
- Christine DeLorenzo
- Division of Molecular Imaging and Neuropathology, Department of Psychiatry, Columbia University College of Physicians and Surgeons, NYSPI Mail Unit 42, 1051 Riverside Drive, New York, NY, USA.
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Carcache D, Vranesic I, Blanz J, Desrayaud S, Fendt M, Glatthar R. Benzimidazoles as Potent and Orally Active mGlu5 Receptor Antagonists with an Improved PK Profile. ACS Med Chem Lett 2011; 2:58-62. [PMID: 24900255 PMCID: PMC4018045 DOI: 10.1021/ml100215b] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Accepted: 10/21/2010] [Indexed: 11/29/2022] Open
Abstract
A focused chemical optimization effort of compound 1 based on metabolite elucidation is described, resulting in 15i, a highly potent and selective mGlu5 receptor antagonist with an improved pharmacokinetic profile compared to 1. Characterization of 15i in vivo in the fear-potentiated startle (FPS) paradigm revealed a robust reduction of conditioned fear behavior. This effect nicely correlates with the rat brain pharmacokinetics.
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48
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Deng PY, Xiao Z, Lei S. Distinct modes of modulation of GABAergic transmission by Group I metabotropic glutamate receptors in rat entorhinal cortex. Hippocampus 2010; 20:980-93. [PMID: 19739246 DOI: 10.1002/hipo.20697] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Activation of metabotropic glutamate receptors (mGluRs) modulates synaptic transmission, whereas the roles of mGluRs in GABAergic transmission in the entorhinal cortex (EC) are elusive. Here, we examined the effects of mGluRs on GABAergic transmission onto the principal neurons in the superficial layers of the EC. Bath application of DHPG, a selective Group I mGluR agonist, increased the frequency and amplitude of spontaneous IPSCs (sIPSCs) whereas application of DCG-IV, an agonist for Group II mGluRs or L-AP4, an agonist for Group III mGluRs failed to change significantly sIPSC frequency and amplitude. Bath application of DHPG failed to change significantly the frequency and amplitude of miniature IPSCs (mIPSCs) recorded in the presence of tetradotoxin but significantly reduced the amplitude of IPSCs evoked by extracellular field stimulation or in synaptically connected interneuron-pyramidal neuron pairs in layer III of the EC. DHPG increased the frequency but reduced the amplitude of APs recorded from entorhinal interneurons. Bath application of DHPG generated membrane depolarization and increased the input resistance of GABAergic interneurons. DHPG-mediated depolarization of GABAergic interneurons was mediated by inhibition of background K(+) channels which are insensitive to extracellular Cs(+), TEA, 4-AP, and Ba(2+). DHPG-induced facilitation of sIPSCs was mediated by mGluR(5) and required the function of Galphaq but was independent of phospholipase C activity. Elevation of synaptic glutamate concentration by bath application of glutamate transporter inhibitors significantly increased sIPSC frequency and amplitude demonstrating a physiological role of mGluRs in GABAergic transmission. Our results provide a cellular and molecular mechanism to explain the physiological and pathological roles of mGluRs in the EC.
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Affiliation(s)
- Pan-Yue Deng
- Department of Pharmacology, Physiology and Therapeutics, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota 58203, USA
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Exploration of structure-based drug design opportunities for mGluRs. Neuropharmacology 2010; 60:93-101. [PMID: 20705075 DOI: 10.1016/j.neuropharm.2010.08.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Accepted: 08/03/2010] [Indexed: 11/22/2022]
Abstract
The metabotropic glutamate receptors (mGluRs) are a subset of the Class C G-Protein Coupled Receptors (GPCRs). Recently, an emerging strategy for drug-discovery efforts targeting mGluRs has been to develop compounds acting at the so-called allosteric site in the 7-transmembrane (7TM) domain, common to all GPCRs, rather than the extracellular (EC) domain containing the orthosteric glutamate-binding site. We examine herein some of the intrinsic relative merits of targeting these two domains. Comparisons are made among amino-acid sequences in the two domains and among X-ray structures and homology models of the EC domain. We show that there is greater sequence diversity in the EC domains than in the transmembrane (TM) domains. Thus, contrary to generally accepted descriptions of there being greater evolutionary pressure to preserve the EC domain, it is the 7TM domain that is more highly conserved. Within the EC domain, the glutamate-binding site of the Venus flytrap region has hitherto received the most attention as a target site. Analysis of examples of the three-dimensional structures of the EC domains at the glutamate-binding site reveals differences as well, thereby supporting the viability of targeting the EC domain, even at the glutamate-binding site, for drug discovery. To exemplify this strategy, we present examples of active compounds identified via high-throughput docking in the EC region.
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50
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Syntheses and pharmacological characterization of novel thiazole derivatives as potential mGluR5 PET ligands. Bioorg Med Chem 2010; 18:6044-54. [DOI: 10.1016/j.bmc.2010.06.070] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2010] [Revised: 06/08/2010] [Accepted: 06/20/2010] [Indexed: 11/19/2022]
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