1
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Teng Y, Yang H, Tian Y. The Development and Application of Tritium-Labeled Compounds in Biomedical Research. Molecules 2024; 29:4109. [PMID: 39274956 PMCID: PMC11397416 DOI: 10.3390/molecules29174109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2024] [Revised: 08/25/2024] [Accepted: 08/28/2024] [Indexed: 09/16/2024] Open
Abstract
With low background radiation, tritiate compounds exclusively emit intense beta particles without structural changes. This makes them a useful tool in the drug discovery arsenal. Thanks to the recent rapid progress in tritium chemistry, the preparation and analysis of tritium-labeled compounds are now much easier, simpler, and cheaper. Pharmacokinetics, autoradiography, and protein binding studies have been much more efficient with the employment of tritium-labeled compounds. This review provides a comprehensive overview of tritium-labeled compounds regarding their properties, synthesis strategies, and applications.
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Affiliation(s)
- Yu Teng
- State Key Laboratory of Bioactive Substances and Function of Natural Medicine, Beijing Key Laboratory of Active Substances Discovery and Drugability Evaluation, Institute of Materia Medica, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing 100050, China
| | - Hong Yang
- State Key Laboratory of Bioactive Substances and Function of Natural Medicine, Beijing Key Laboratory of Active Substances Discovery and Drugability Evaluation, Institute of Materia Medica, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing 100050, China
| | - Yulin Tian
- State Key Laboratory of Bioactive Substances and Function of Natural Medicine, Beijing Key Laboratory of Active Substances Discovery and Drugability Evaluation, Institute of Materia Medica, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing 100050, China
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2
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Xue L, Jie CVML, Desrayaud S, Auberson YP. Developing Low Molecular Weight PET and SPECT Imaging Agents. ChemMedChem 2024; 19:e202400094. [PMID: 38634545 DOI: 10.1002/cmdc.202400094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 04/17/2024] [Accepted: 04/17/2024] [Indexed: 04/19/2024]
Abstract
Imaging agents for positron emission tomography (PET) and single-photon emission computerized tomography (SPECT) have shown their utility in many situations, answering clinical questions related to drug development and medical considerations. The discovery and development of imaging agents follow a well-understood process, with variations related to available starting points and to the envisaged imaging application. This article describes the general development path leading from the expression of an imaging need and project initiation to a clinically usable imaging agent. The definition of the project rationale, the design and optimization of early leads, and the assessment of the imaging potential of an imaging agent candidate are followed by preclinical and clinical development activities that differ from those required for therapeutic agents. These include radiolabeling with a positron emitter and first-in-human clinical studies, to rapidly evaluate the ability of a new imaging agent to address the questions it was designed to answer.
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Affiliation(s)
- Lian Xue
- Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade Parkville, Victoria 3052, Australia
| | - Caitlin V M L Jie
- ETH Zürich, Department of Chemistry and Applied Biosciences Center for Radiopharmaceutical Sciences, Vladimir-Prelog Weg 1-5/10, 8093, Zürich, Switzerland
| | - Sandrine Desrayaud
- Novartis Biomedical Research, In Vivo preclinical PK/ADME, Novartis campus, WSJ-352/6/73.01, 4056, Basel, Switzerland
| | - Yves P Auberson
- Novartis Biomedical Research, Global Discovery Chemistry, Novartis campus, WSJ-88.10.100, 4056, Basel, Switzerland
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3
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Lopresti BJ, Royse SK, Mathis CA, Tollefson SA, Narendran R. Beyond monoamines: I. Novel targets and radiotracers for Positron emission tomography imaging in psychiatric disorders. J Neurochem 2023; 164:364-400. [PMID: 35536762 DOI: 10.1111/jnc.15615] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 04/05/2022] [Accepted: 04/06/2022] [Indexed: 10/18/2022]
Abstract
With the emergence of positron emission tomography (PET) in the late 1970s, psychiatry had access to a tool capable of non-invasive assessment of human brain function. Early applications in psychiatry focused on identifying characteristic brain blood flow and metabolic derangements using radiotracers such as [15 O]H2 O and [18 F]FDG. Despite the success of these techniques, it became apparent that more specific probes were needed to understand the neurochemical bases of psychiatric disorders. The first neurochemical PET imaging probes targeted sites of action of neuroleptic (dopamine D2 receptors) and psychoactive (serotonin receptors) drugs. Based on the centrality of monoamine dysfunction in psychiatric disorders and the measured success of monoamine-enhancing drugs in treating them, the next 30 years witnessed the development of an armamentarium of PET radiopharmaceuticals and imaging methodologies for studying monoamines. Continued development of monoamine-enhancing drugs over this time however was less successful, realizing only modest gains in efficacy and tolerability. As patent protection for many widely prescribed and profitable psychiatric drugs lapsed, drug development pipelines shifted away from monoamines in search of novel targets with the promises of improved efficacy, or abandoned altogether. Over this period, PET radiopharmaceutical development activities closely paralleled drug development priorities resulting in the development of new PET imaging agents for non-monoamine targets. Part one of this review will briefly survey novel PET imaging targets with relevance to the field of psychiatry, which include the metabotropic glutamate receptor type 5 (mGluR5), purinergic P2 X7 receptor, type 1 cannabinoid receptor (CB1 ), phosphodiesterase 10A (PDE10A), and describe radiotracers developed for these and other targets that have matured to human subject investigations. Current limitations of the targets and techniques will also be discussed.
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Affiliation(s)
- Brian J Lopresti
- Departments of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Sarah K Royse
- Departments of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Chester A Mathis
- Departments of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Savannah A Tollefson
- Departments of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Rajesh Narendran
- Departments of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.,Departments of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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4
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Auberson YP, Lièvre A, Desrayaud S, Briard E. A practical approach to the optimization of positron emission tomography (PET) imaging agents for the central nervous system. J Labelled Comp Radiopharm 2022; 65:343-350. [PMID: 36148533 DOI: 10.1002/jlcr.4004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 09/20/2022] [Accepted: 09/21/2022] [Indexed: 11/08/2022]
Abstract
The discovery of novel imaging agents for positron emission tomography (PET) relies on medicinal chemistry best practices, including a good understanding of molecular and pharmacological properties required for the acquisition of relevant, high-quality images. This short note reviews the characteristics of a series of clinically successful imaging agents, providing guidance for the optimization of such molecular tools. PET imaging plays an important role in staging disease and in helping clinical dose selection, which is critical for the efficient development of drug candidates.
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Affiliation(s)
- Yves P Auberson
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Akané Lièvre
- Novartis Institutes for BioMedical Research, Basel, Switzerland
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5
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Zimmermann M, Minuzzi L, Aliaga Aliaga A, Guiot MC, Hall JA, Soucy JP, Massarweh G, El Mestikawy S, Rosa-Neto P, Kobayashi E. Reduced Metabotropic Glutamate Receptor Type 5 Availability in the Epileptogenic Hippocampus: An in vitro Study. Front Neurol 2022; 13:888479. [PMID: 35937057 PMCID: PMC9355376 DOI: 10.3389/fneur.2022.888479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 06/02/2022] [Indexed: 11/23/2022] Open
Abstract
Abnormalities in the expression of metabotropic glutamate receptor type 5 (mGluR5) have been observed in the hippocampus of patients with drug-resistant mesial Temporal Lobe Epilepsy (mTLE). Ex-vivo studies in mTLE hippocampal surgical specimens have shown increased mGluR5 immunoreactivity, while in vivo whole brain imaging using positron emission tomography (PET) demonstrated reduced hippocampal mGluR5 availability. To further understand mGluR5 abnormalities in mTLE, we performed a saturation autoradiography study with [3H]ABP688 (a negative mGluR5 allosteric modulator). We aimed to evaluate receptor density (Bmax) and dissociation constants (KD) in hippocampal mTLE surgical specimens and in non-epilepsy hippocampi from necropsy controls. mTLE specimens showed a 43.4% reduction in receptor density compared to control hippocampi, which was independent of age, sex and KD (multiple linear regression analysis). There was no significant difference in KD between the groups, which suggests that the decreased mGluR5 availability found in vivo with PET cannot be attributed to reduced affinity between ligand and binding site. The present study supports that changes within the epileptogenic tissue include mGluR5 internalization or conformational changes that reduce [3H]ABP688 binding, as previously suggested in mTLE patients studied in vivo.
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Affiliation(s)
- Maria Zimmermann
- Department of Neurology and Neurosurgery, Montréal Neurological Institute, McGill University, Montréal, QC, Canada
- Translational Neuroimaging Laboratory, Douglas Research Institute, McGill University, Montréal, QC, Canada
| | - Luciano Minuzzi
- Translational Neuroimaging Laboratory, Douglas Research Institute, McGill University, Montréal, QC, Canada
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON, Canada
| | - Arturo Aliaga Aliaga
- Translational Neuroimaging Laboratory, Douglas Research Institute, McGill University, Montréal, QC, Canada
- PET Unit, McConnell Brain Imaging Centre, Montréal, QC, Canada
| | | | - Jeffery A. Hall
- Department of Neurology and Neurosurgery, Montréal Neurological Institute, McGill University, Montréal, QC, Canada
| | - Jean-Paul Soucy
- Department of Neurology and Neurosurgery, Montréal Neurological Institute, McGill University, Montréal, QC, Canada
- PET Unit, McConnell Brain Imaging Centre, Montréal, QC, Canada
| | | | - Salah El Mestikawy
- Department of Psychiatry, Douglas Research Institute, McGill University, Montréal, QC, Canada
| | - Pedro Rosa-Neto
- Department of Neurology and Neurosurgery, Montréal Neurological Institute, McGill University, Montréal, QC, Canada
- Translational Neuroimaging Laboratory, Douglas Research Institute, McGill University, Montréal, QC, Canada
| | - Eliane Kobayashi
- Department of Neurology and Neurosurgery, Montréal Neurological Institute, McGill University, Montréal, QC, Canada
- *Correspondence: Eliane Kobayashi
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6
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Yang H, Huang Z, Lehnherr D, Lam YH, Ren S, Strotman NA. Efficient Aliphatic Hydrogen-Isotope Exchange with Tritium Gas through the Merger of Photoredox and Hydrogenation Catalysts. J Am Chem Soc 2022; 144:5010-5022. [PMID: 35263094 DOI: 10.1021/jacs.1c13265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Employment of a combination of an organophotoredox catalyst with Wilkinson's catalyst (Rh(PPh3)3Cl) has given rise to an unprecedented method for hydrogen-isotope exchange (HIE) of aliphatic C(sp3)-H bonds of complex pharmaceuticals using T2 gas directly. Wilkinson's catalyst, commonly used for catalytic hydrogenations, was exploited as a precatalyst for activation of D2 or T2 and hydrogen atom transfer. In this combined methodology and mechanistic study, we demonstrate that by coupling photocatalysis with Rh catalysis, carbon-centered radicals generated via photoredox catalysis can be intercepted by Rh-hydride intermediates to deliver an effective hydrogen atom donor for hydrogen-isotope labeling of complex molecules in one step. By optimizing the ratio of the photocatalyst and Wilkinson's catalyst to balance the rate of the dual catalytic cycles, we can achieve efficient HIE and high recovery yield. This protocol was readily applied to direct HIE of C(sp3)-H bonds in 10 complex drug molecules, showing high isotope incorporation efficiency and exceptionally good functional group tolerance and demonstrating this approach as a practical and attractive labeling method for deuteration and tritiation.
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Affiliation(s)
- Haifeng Yang
- Process Research & Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Zheng Huang
- Process Research & Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Dan Lehnherr
- Process Research & Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Yu-Hong Lam
- Computational and Structural Chemistry, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Sumei Ren
- Process Research & Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Neil A Strotman
- Process Research & Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
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7
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Bennett KA, Sergeev E, MacSweeney CP, Bakker G, Cooper AE. Understanding Exposure-Receptor Occupancy Relationships for Metabotropic Glutamate Receptor 5 Negative Allosteric Modulators across a Range of Preclinical and Clinical Studies. J Pharmacol Exp Ther 2021; 377:157-168. [PMID: 33541889 DOI: 10.1124/jpet.120.000371] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 01/26/2021] [Indexed: 01/17/2023] Open
Abstract
The metabotropic glutamate receptor 5 (mGlu5) is a recognized central nervous system therapeutic target for which several negative allosteric modulator (NAM) drug candidates have or are continuing to be investigated for various disease indications in clinical development. Direct measurement of target receptor occupancy (RO) is extremely useful to help design and interpret efficacy and safety in nonclinical and clinical studies. In the mGlu5 field, this has been successfully achieved by monitoring displacement of radiolabeled ligands, specifically binding to the mGlu5 receptor, in the presence of an mGlu5 NAM using in vivo and ex vivo binding in rodents and positron emission tomography imaging in cynomolgus monkeys and humans. The aim of this study was to measure the RO of the mGlu5 NAM HTL0014242 in rodents and cynomolgus monkeys and to compare its plasma and brain exposure-RO relationships with those of clinically tested mGlu5 NAMs dipraglurant, mavoglurant, and basimglurant. Potential sources of variability that may contribute to these relationships were explored. Distinct plasma exposure-response relationships were found for each mGlu5 NAM, with >100-fold difference in plasma exposure for a given level of RO. However, a unified exposure-response relationship was observed when both unbound brain concentration and mGlu5 affinity were considered. This relationship showed <10-fold overall difference, was fitted with a Hill slope that was not significantly different from 1, and appeared consistent with a simple Emax model. This is the first time this type of comparison has been conducted, demonstrating a unified brain exposure-RO relationship across several species and mGlu5 NAMs with diverse properties. SIGNIFICANCE STATEMENT: Despite the long history of mGlu5 as a therapeutic target and progression of multiple compounds to the clinic, no formal comparison of exposure-receptor occupancy relationships has been conducted. The data from this study indicate for the first time that a consistent, unified relationship can be observed between exposure and mGlu5 receptor occupancy when unbound brain concentration and receptor affinity are taken into account across a range of species for a diverse set of mGlu5 negative allosteric modulators, including a new drug candidate, HTL0014242.
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Affiliation(s)
| | | | | | - Geor Bakker
- Sosei Heptares, Cambridge, CB21 6DG, United Kingdom
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8
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The pro-psychotic metabotropic glutamate receptor compounds fenobam and AZD9272 share binding sites with monoamine oxidase-B inhibitors in humans. Neuropharmacology 2019; 162:107809. [PMID: 31589885 DOI: 10.1016/j.neuropharm.2019.107809] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Revised: 09/18/2019] [Accepted: 10/02/2019] [Indexed: 11/22/2022]
Abstract
The metabotropic glutamate receptor 5 (mGluR5) ligands fenobam and AZD9272 have been reported to induce psychosis-like adverse events and to bind at unknown, non-GluR5-related, sites. Based on similarities of the regional binding patterns for [11C]AZD9272 and the monoamine oxidase-B (MAO-B) radioligand [11C]L-deprenyl-D2 in PET studies of the human brain we tested the hypothesis that the unique binding of fenobam and AZD9272 may represent specific binding to the MAO-B. PET data previously acquired for subjects examined using [11C]AZD9272 or [11C]L-deprenyl-D2 were re-evaluated to assess the correlations between radioligand binding parameters in human brain. In addition, the pharmacology of AZD9272 binding sites was characterized using competition binding studies carried out in vivo in non-human primates (NHPs) and in vitro using autoradiography in selected human brain regions. The regional binding of [11C]AZD9272 in human brain was closely correlated with that of [11C]L-deprenyl-D2. In PET studies of NHP brain administration of the MAO-B ligand L-deprenyl inhibited binding of radiolabeled AZD9272 and administration of fenobam inhibited binding of [11C]L-deprenyl-D2. Binding of radiolabeled AZD9272 in vitro was potently inhibited by fenobam or MAO-B compounds, and [11C]L-deprenyl-D2 binding was inhibited by fenobam or AZD9272. The findings are consistent with the hypothesis that both fenobam and AZD9272 bind to the MAO-B, which may be of relevance for understanding the mechanism of the psychosis-like adverse events reported for these compounds. Such understanding may serve as a lead to generate new models for the pathophysiology of psychosis.
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9
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Bdair H, Tsai IH, Smart K, Benkelfat C, Leyton M, Kostikov A. Radiosynthesis of the diastereomerically pure (E)-[ 11 C]ABP688. J Labelled Comp Radiopharm 2019; 62:860-864. [PMID: 31418468 DOI: 10.1002/jlcr.3802] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Revised: 08/06/2019] [Accepted: 08/07/2019] [Indexed: 11/12/2022]
Abstract
We report an efficient protocol for the radiosynthesis of diastereomerically pure (E)-[11 C]ABP688, a positron emission tomography (PET) tracer for metabotropic glutamate type 5 (mGlu5) receptor imaging. The protocol reliably provides sterile and pyrogen-free formulation of (E)-[11 C]ABP688 suitable for preclinical and clinical PET imaging with >99% diastereomeric excess (d.e.), >99% overall radiochemical purity (RCP), 14.9 ± 4.3% decay-corrected radiochemical yield (RCY), and 148.86 ± 79.8 GBq/μmol molar activity in 40 minutes from the end of bombardment.
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Affiliation(s)
- Hussein Bdair
- McGill University, Montreal Neurological Institute, Montreal, Quebec, Canada.,McGill University, Department of Psychiatry, Montreal, Quebec, Canada
| | - I-Huang Tsai
- McGill University, McConnell Brain Imaging Centre, Montreal Neurological Institute, Montreal, Quebec, Canada
| | - Kelly Smart
- Yale University School of Medicine, Yale PET Center, New Haven, Connecticut
| | - Chawki Benkelfat
- McGill University, Department of Psychiatry, Montreal, Quebec, Canada
| | - Marco Leyton
- McGill University, Department of Psychiatry, Montreal, Quebec, Canada
| | - Alexey Kostikov
- McGill University, Montreal Neurological Institute, Montreal, Quebec, Canada.,McGill University, McConnell Brain Imaging Centre, Montreal Neurological Institute, Montreal, Quebec, Canada.,Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
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10
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mGluR5 Modulation of Behavioral and Epileptic Phenotypes in a Mouse Model of Tuberous Sclerosis Complex. Neuropsychopharmacology 2018; 43:1457-1465. [PMID: 29206810 PMCID: PMC5916364 DOI: 10.1038/npp.2017.295] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 11/03/2017] [Accepted: 11/28/2017] [Indexed: 12/13/2022]
Abstract
Drugs targeting metabotropic glutamate receptor 5 (mGluR5) have therapeutic potential in autism spectrum disorders (ASD), including tuberous sclerosis complex (TSC). The question whether inhibition or potentiation of mGluR5 could be beneficial depends, among other factors, on the specific indication. To facilitate the development of mGluR5 treatment strategies, we tested the therapeutic utility of mGluR5 negative and positive allosteric modulators (an mGluR5 NAM and PAM) for TSC, using a mutant mouse model with neuronal loss of Tsc2 that demonstrates disease-related phenotypes, including behavioral symptoms of ASD and epilepsy. This model uniquely enables the in vivo characterization and rescue of the electrographic seizures associated with TSC. We demonstrate that inhibition of mGluR5 corrects hyperactivity, seizures, and elevated de novo synaptic protein synthesis. Conversely, positive allosteric modulation of mGluR5 results in the exacerbation of hyperactivity and epileptic phenotypes. The data suggest a meaningful therapeutic potential for mGluR5 NAMs in TSC, which warrants clinical exploration and the continued development of mGluR5 therapies.
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11
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Varnäs K, Juréus A, Finnema SJ, Johnström P, Raboisson P, Amini N, Takano A, Stepanov V, Halldin C, Farde L. The metabotropic glutamate receptor 5 radioligand [ 11C]AZD9272 identifies unique binding sites in primate brain. Neuropharmacology 2018; 135:455-463. [PMID: 29608920 DOI: 10.1016/j.neuropharm.2018.03.039] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 03/25/2018] [Accepted: 03/29/2018] [Indexed: 12/11/2022]
Abstract
The metabotropic glutamate receptor 5 (mGluR5) is a target for drug development and for imaging studies of the glutamate system in neurological and psychiatric disorders. [11C]AZD9272 is a selective mGluR5 PET radioligand that is structurally different from hitherto applied mGluR5 radioligands. In the present investigation we compared the binding patterns of radiolabeled AZD9272 and other mGluR5 radioligands in the non-human primate (NHP) brain. PET studies were undertaken using [11C]AZD9272 and the commonly applied mGluR5 radioligand [11C]ABP688. Autoradiography studies were performed in vitro using [3H]AZD9272 and the standard mGluR5 radioligands [3H]M-MTEP and [3H]ABP688 in NHP tissue. Competition binding studies were undertaken in vivo and in vitro using different mGluR5 selective compounds as inhibitors. In comparison to other mGluR5 radioligands radiolabeled AZD9272 displayed a distinct regional distribution pattern with high binding in ventral striatum, midbrain, thalamus and cerebellum. While the binding of [11C]AZD9272 was almost completely inhibited by the structurally unique mGluR5 compound fenobam (2.0 mg/kg; 98% occupancy), it was only partially inhibited (46% and 20%, respectively) by the mGluR5 selective compounds ABP688 and MTEP, at a dose (2.0 mg/kg) expected to saturate the mGluR5. Autoradiography studies using [3H]AZD9272 confirmed a distinct pharmacologic profile characterized by preferential sensitivity to fenobam. The distinctive binding in ventral striato-pallido-thalamic circuits and shared pharmacologic profile with the pro-psychotic compound fenobam warrants further examination of [11C]AZD9272 for potential application in psychiatric neuroimaging studies.
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Affiliation(s)
- Katarina Varnäs
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden.
| | | | - Sjoerd J Finnema
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden
| | - Peter Johnström
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden; PET Science Centre, Precision Medicine and Genomics, IMED Biotech Unit, AstraZeneca, Karolinska Institutet, Sweden
| | | | - Nahid Amini
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden
| | - Akihiro Takano
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden
| | - Vladimir Stepanov
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden
| | - Christer Halldin
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden
| | - Lars Farde
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden; PET Science Centre, Precision Medicine and Genomics, IMED Biotech Unit, AstraZeneca, Karolinska Institutet, Sweden
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12
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Del Guerra A, Ahmad S, Avram M, Belcari N, Berneking A, Biagi L, Bisogni MG, Brandl F, Cabello J, Camarlinghi N, Cerello P, Choi CH, Coli S, Colpo S, Fleury J, Gagliardi V, Giraudo G, Heekeren K, Kawohl W, Kostou T, Lefaucheur JL, Lerche C, Loudos G, Morrocchi M, Muller J, Mustafa M, Neuner I, Papadimitroulas P, Pennazio F, Rajkumar R, Brambilla CR, Rivoire J, Kops ER, Scheins J, Schimpf R, Shah NJ, Sorg C, Sportelli G, Tosetti M, Trinchero R, Wyss C, Ziegler S. TRIMAGE: A dedicated trimodality (PET/MR/EEG) imaging tool for schizophrenia. Eur Psychiatry 2018; 50:7-20. [PMID: 29358016 DOI: 10.1016/j.eurpsy.2017.11.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 11/15/2017] [Accepted: 11/16/2017] [Indexed: 02/02/2023] Open
Abstract
Simultaneous PET/MR/EEG (Positron Emission Tomography - Magnetic Resonance - Electroencephalography), a new tool for the investigation of neuronal networks in the human brain, is presented here within the framework of the European Union Project TRIMAGE. The trimodal, cost-effective PET/MR/EEG imaging tool makes use of cutting edge technology both in PET and in MR fields. A novel type of magnet (1.5T, non-cryogenic) has been built together with a PET scanner that makes use of the most advanced photodetectors (i.e., SiPM matrices), scintillators matrices (LYSO) and digital electronics. The combined PET/MR/EEG system is dedicated to brain imaging and has an inner diameter of 260 mm and an axial Field-of-View of 160 mm. It enables the acquisition and assessment of molecular metabolic information with high spatial and temporal resolution in a given brain simultaneously. The dopaminergic system and the glutamatergic system in schizophrenic patients are investigated via PET, the same physiological/pathophysiological conditions with regard to functional connectivity, via fMRI, and its electrophysiological signature via EEG. In addition to basic neuroscience questions addressing neurovascular-metabolic coupling, this new methodology lays the foundation for individual physiological and pathological fingerprints for a wide research field addressing healthy aging, gender effects, plasticity and different psychiatric and neurological diseases. The preliminary performances of two components of the imaging tool (PET and MR) are discussed. Initial results of the search of possible candidates for suitable schizophrenia biomarkers are also presented as obtained with PET/MR systems available to the collaboration.
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Affiliation(s)
- Alberto Del Guerra
- Dipartimento di Fisica "E. Fermi", Università di Pisa, Italy; INFN, Sezione di Pisa, Pisa, Italy.
| | | | - Mihai Avram
- Nuklearmedinische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, Munich, Germany; Department of Neuroradiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany; Neuroimaging Center (TUM-NIC), Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Nicola Belcari
- Dipartimento di Fisica "E. Fermi", Università di Pisa, Italy; INFN, Sezione di Pisa, Pisa, Italy
| | - Arne Berneking
- Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine, INM4, Jülich, Germany
| | - Laura Biagi
- IRCSS, Stella Maris, Calambrone, Pisa, Italy
| | - Maria Giuseppina Bisogni
- Dipartimento di Fisica "E. Fermi", Università di Pisa, Italy; INFN, Sezione di Pisa, Pisa, Italy
| | - Felix Brandl
- Department of Neuroradiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany; Neuroimaging Center (TUM-NIC), Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Jorge Cabello
- Nuklearmedinische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Niccolò Camarlinghi
- Dipartimento di Fisica "E. Fermi", Università di Pisa, Italy; INFN, Sezione di Pisa, Pisa, Italy
| | | | - Chang-Hoon Choi
- Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine, INM4, Jülich, Germany
| | - Silvia Coli
- Istituto Nazionale di Fisica Nucleare, Sezione di Torino, Torino, Italy
| | | | | | - Vito Gagliardi
- Dipartimento di Fisica "E. Fermi", Università di Pisa, Italy; INFN, Sezione di Pisa, Pisa, Italy
| | - Giuseppe Giraudo
- Istituto Nazionale di Fisica Nucleare, Sezione di Torino, Torino, Italy
| | - Karsten Heekeren
- Department of Psychiatry, Psychotherapy and Psychosomatics, University Hospital of Psychiatry Zurich, University of Zurich, Switzerland
| | - Wolfram Kawohl
- Department of Psychiatry, Psychotherapy and Psychosomatics, University Hospital of Psychiatry Zurich, University of Zurich, Switzerland; Department of Psychiatry and Psychotherapy, Psychiatric Services of Aargovia, Switzerland
| | | | | | - Christoph Lerche
- Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine, INM4, Jülich, Germany
| | - George Loudos
- Technological Educational Institute of Athens, Greece
| | - Matteo Morrocchi
- Dipartimento di Fisica "E. Fermi", Università di Pisa, Italy; INFN, Sezione di Pisa, Pisa, Italy
| | | | - Mona Mustafa
- Nuklearmedinische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Irene Neuner
- Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine, INM4, Jülich, Germany; Department of Psychiatry, Psychotherapy and Psychosomatics, Faculty of Medicine, RWTH Aachen University, JARA Brain, Aachen, Germany
| | | | | | - Ravichandran Rajkumar
- Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine, INM4, Jülich, Germany; Department of Psychiatry, Psychotherapy and Psychosomatics, Faculty of Medicine, RWTH Aachen University, JARA Brain, Aachen, Germany
| | - Cláudia Régio Brambilla
- Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine, INM4, Jülich, Germany
| | | | - Elena Rota Kops
- Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine, INM4, Jülich, Germany
| | - Jürgen Scheins
- Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine, INM4, Jülich, Germany
| | | | - N Jon Shah
- Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine, INM4, Jülich, Germany
| | - Christian Sorg
- Department of Neuroradiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany; Neuroimaging Center (TUM-NIC), Klinikum rechts der Isar, Technische Universität München, Munich, Germany; Department of Psychiatry, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Giancarlo Sportelli
- Dipartimento di Fisica "E. Fermi", Università di Pisa, Italy; INFN, Sezione di Pisa, Pisa, Italy
| | | | | | - Christine Wyss
- Department of Psychiatry, Psychotherapy and Psychosomatics, University Hospital of Psychiatry Zurich, University of Zurich, Switzerland
| | - Sibylle Ziegler
- Nuklearmedinische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, Munich, Germany; Department of Nuclear Medicine, University Hospital, LMU, Munich, Germany
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Atzrodt J, Derdau V, Kerr WJ, Reid M. Deuterium- und tritiummarkierte Verbindungen: Anwendungen in den modernen Biowissenschaften. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201704146] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Jens Atzrodt
- Isotope Chemistry and Metabolite Synthesis, Integrated Drug Discovery, Medicinal Chemistry; Industriepark Höchst, G876 65926 Frankfurt Deutschland
| | - Volker Derdau
- Isotope Chemistry and Metabolite Synthesis, Integrated Drug Discovery, Medicinal Chemistry; Industriepark Höchst, G876 65926 Frankfurt Deutschland
| | - William J. Kerr
- Department of Pure and Applied Chemistry, WestCHEM; University of Strathclyde; 295 Cathedral Street Glasgow Scotland G1 1XL Großbritannien
| | - Marc Reid
- Department of Pure and Applied Chemistry, WestCHEM; University of Strathclyde; 295 Cathedral Street Glasgow Scotland G1 1XL Großbritannien
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Atzrodt J, Derdau V, Kerr WJ, Reid M. Deuterium- and Tritium-Labelled Compounds: Applications in the Life Sciences. Angew Chem Int Ed Engl 2018; 57:1758-1784. [PMID: 28815899 DOI: 10.1002/anie.201704146] [Citation(s) in RCA: 407] [Impact Index Per Article: 67.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 07/27/2017] [Indexed: 12/19/2022]
Abstract
Hydrogen isotopes are unique tools for identifying and understanding biological and chemical processes. Hydrogen isotope labelling allows for the traceless and direct incorporation of an additional mass or radioactive tag into an organic molecule with almost no changes in its chemical structure, physical properties, or biological activity. Using deuterium-labelled isotopologues to study the unique mass-spectrometric patterns generated from mixtures of biologically relevant molecules drastically simplifies analysis. Such methods are now providing unprecedented levels of insight in a wide and continuously growing range of applications in the life sciences and beyond. Tritium (3 H), in particular, has seen an increase in utilization, especially in pharmaceutical drug discovery. The efforts and costs associated with the synthesis of labelled compounds are more than compensated for by the enhanced molecular sensitivity during analysis and the high reliability of the data obtained. In this Review, advances in the application of hydrogen isotopes in the life sciences are described.
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Affiliation(s)
- Jens Atzrodt
- Isotope Chemistry and Metabolite Synthesis, Integrated Drug Discovery, Medicinal Chemistry, Industriepark Höchst, G876, 65926, Frankfurt, Germany
| | - Volker Derdau
- Isotope Chemistry and Metabolite Synthesis, Integrated Drug Discovery, Medicinal Chemistry, Industriepark Höchst, G876, 65926, Frankfurt, Germany
| | - William J Kerr
- Department of Pure and Applied Chemistry, WestCHEM, University of Strathclyde, 295 Cathedral Street, Glasgow, Scotland, G1 1XL, UK
| | - Marc Reid
- Department of Pure and Applied Chemistry, WestCHEM, University of Strathclyde, 295 Cathedral Street, Glasgow, Scotland, G1 1XL, UK
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15
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Deficient striatal adaptation in aminergic and glutamatergic neurotransmission is associated with tardive dyskinesia in non-human primates exposed to antipsychotic drugs. Neuroscience 2017; 361:43-57. [DOI: 10.1016/j.neuroscience.2017.07.068] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 07/10/2017] [Accepted: 07/29/2017] [Indexed: 11/23/2022]
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16
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Lee B, Kim YK, Lee JY, Kim YJ, Lee YS, Lee DS, Chung JK, Jeong JM. Preclinical anaylses of [ 18F]cEFQ as a PET tracer for imaging metabotropic glutamate receptor type 1 (mGluR1). J Cereb Blood Flow Metab 2017; 37:2283-2293. [PMID: 27501957 PMCID: PMC5464717 DOI: 10.1177/0271678x16663948] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Metabotropic glutamate receptor type 1 (mGluR1) is related with various neurological and psychiatric diseases, such as anxiety, depression, epilepsy, Parkinson's disease, and neuropathic pain. Hence, mGluR1 is an important target for drug development and imaging. We synthesized [18F]cEFQ (3-ethyl-2-[18F]fluoroquinolin-6-yl cis-(4-methoxycyclohexyl)methanone) as a PET tracer for selective mGluR1 imaging and evaluated its properties in rodents. A chloroquinoline precursor was labeled by a nucleophilic substitution reaction, and the resulting [18F]cEFQ was obtained with high radiochemical purity (>99%) and specific activity (63-246 GBq/µmol). The log D value was 3.24, and the initial brain uptake at 10 min was over 4% of injected dose per gram in BALB/c mice. According to PET/CT and autoradiography in SD rats, [18F]cEFQ showed wide distribution in the whole brain and the highest uptake in the cerebellum. Pre-treatment with unlabeled cEFQ or the mGluR1-specific antagonist JNJ16259685 blocked the uptake of [18F]cEFQ. However, the uptake was not blocked by pre-treatment with the mGluR5-specific antagonist ABP688. The trans isomer [18F]tEFQ did not show high uptake in the mGluR1-rich region. [18F]cEFQ was straightforwardly prepared using a chloro-derivative precursor. Its feasibility as a specific and selective PET agent for imaging mGluR1 was proved by in vitro and in vivo experiments using rodents.
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Affiliation(s)
- Boeun Lee
- 1 Department of Nuclear Medicine, Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.,2 Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, and College of Medicine or College of Pharmacy, Seoul National University, Seoul, Republic of Korea
| | - Yu Kyeong Kim
- 1 Department of Nuclear Medicine, Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.,3 Department of Nuclear Medicine, Seoul Metropolitan Government Boramae Medical Center, Seoul National University, Seoul, Republic of Korea
| | - Ji Youn Lee
- 1 Department of Nuclear Medicine, Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.,4 Cancer Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea.,5 Department of Biomedical Sciences, Seoul National University Graduate School, Seoul, Republic of Korea
| | - Young Joo Kim
- 1 Department of Nuclear Medicine, Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.,4 Cancer Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Yun-Sang Lee
- 1 Department of Nuclear Medicine, Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.,2 Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, and College of Medicine or College of Pharmacy, Seoul National University, Seoul, Republic of Korea
| | - Dong Soo Lee
- 1 Department of Nuclear Medicine, Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.,2 Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, and College of Medicine or College of Pharmacy, Seoul National University, Seoul, Republic of Korea
| | - June-Key Chung
- 1 Department of Nuclear Medicine, Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.,4 Cancer Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Jae Min Jeong
- 1 Department of Nuclear Medicine, Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.,4 Cancer Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea.,5 Department of Biomedical Sciences, Seoul National University Graduate School, Seoul, Republic of Korea
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17
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Peterlik D, Stangl C, Bauer A, Bludau A, Keller J, Grabski D, Killian T, Schmidt D, Zajicek F, Jaeschke G, Lindemann L, Reber SO, Flor PJ, Uschold-Schmidt N. Blocking metabotropic glutamate receptor subtype 5 relieves maladaptive chronic stress consequences. Brain Behav Immun 2017; 59:79-92. [PMID: 27524668 DOI: 10.1016/j.bbi.2016.08.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 07/29/2016] [Accepted: 08/10/2016] [Indexed: 12/22/2022] Open
Abstract
Etiology and pharmacotherapy of stress-related psychiatric conditions and somatoform disorders are areas of high unmet medical need. Stressors holding chronic plus psychosocial components thereby bear the highest health risk. Although the metabotropic glutamate receptor subtype 5 (mGlu5) is well studied in the context of acute stress-induced behaviors and physiology, virtually nothing is known about its potential involvement in chronic psychosocial stress. Using the mGlu5 negative allosteric modulator CTEP (2-chloro-4-[2-[2,5-dimethyl-1-[4-(trifluoromethoxy)phenyl]imidazol-4yl]ethynyl]pyridine), a close analogue of the clinically active drug basimglurant - but optimized for rodent studies, as well as mGlu5-deficient mice in combination with a mouse model of male subordination (termed CSC, chronic subordinate colony housing), we demonstrate that mGlu5 mediates multiple physiological, immunological, and behavioral consequences of chronic psychosocial stressor exposure. For instance, CTEP dose-dependently relieved hypothalamo-pituitary-adrenal axis dysfunctions, colonic inflammation as well as the CSC-induced increase in innate anxiety; genetic ablation of mGlu5 in mice largely reproduced the stress-protective effects of CTEP and additionally ameliorated CSC-induced physiological anxiety. Interestingly, CSC also induced an upregulation of mGlu5 in the hippocampus, a stress-regulating brain area. Taken together, our findings provide evidence that mGlu5 is an important mediator for a wide range of chronic psychosocial stress-induced alterations and a potentially valuable drug target for the treatment of chronic stress-related pathologies in man.
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Affiliation(s)
- Daniel Peterlik
- Faculty of Biology and Preclinical Medicine, Laboratory of Molecular and Cellular Neurobiology, University of Regensburg, D-93053 Regensburg, Germany
| | - Christina Stangl
- Faculty of Biology and Preclinical Medicine, Laboratory of Molecular and Cellular Neurobiology, University of Regensburg, D-93053 Regensburg, Germany
| | - Amelie Bauer
- Faculty of Biology and Preclinical Medicine, Laboratory of Molecular and Cellular Neurobiology, University of Regensburg, D-93053 Regensburg, Germany
| | - Anna Bludau
- Faculty of Biology and Preclinical Medicine, Laboratory of Molecular and Cellular Neurobiology, University of Regensburg, D-93053 Regensburg, Germany
| | - Jana Keller
- Faculty of Biology and Preclinical Medicine, Laboratory of Molecular and Cellular Neurobiology, University of Regensburg, D-93053 Regensburg, Germany
| | - Dominik Grabski
- Faculty of Biology and Preclinical Medicine, Laboratory of Molecular and Cellular Neurobiology, University of Regensburg, D-93053 Regensburg, Germany
| | - Tobias Killian
- Faculty of Biology and Preclinical Medicine, Laboratory of Molecular and Cellular Neurobiology, University of Regensburg, D-93053 Regensburg, Germany
| | - Dominic Schmidt
- Institute of Immunology, University of Regensburg, D-93042 Regensburg, Germany
| | - Franziska Zajicek
- Faculty of Biology and Preclinical Medicine, Laboratory of Molecular and Cellular Neurobiology, University of Regensburg, D-93053 Regensburg, Germany
| | - Georg Jaeschke
- Roche Pharmaceutical Research and Early Development, Discovery Chemistry, Roche Innovation Center Basel, CH-4070 Basel, Switzerland
| | - Lothar Lindemann
- Roche Pharmaceutical Research and Early Development, Discovery Neuroscience, Neuroscience, Ophthalmology, and Rare Diseases, Roche Innovation Center Basel, CH-4070 Basel, Switzerland
| | - Stefan O Reber
- Laboratory for Molecular Psychosomatics, Clinic for Psychosomatic Medicine and Psychotherapy, University of Ulm, D-89081 Ulm, Germany
| | - Peter J Flor
- Faculty of Biology and Preclinical Medicine, Laboratory of Molecular and Cellular Neurobiology, University of Regensburg, D-93053 Regensburg, Germany.
| | - Nicole Uschold-Schmidt
- Faculty of Biology and Preclinical Medicine, Laboratory of Molecular and Cellular Neurobiology, University of Regensburg, D-93053 Regensburg, Germany.
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18
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Slifstein M, Abi-Dargham A. Recent Developments in Molecular Brain Imaging of Neuropsychiatric Disorders. Semin Nucl Med 2016; 47:54-63. [PMID: 27987558 DOI: 10.1053/j.semnuclmed.2016.09.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Molecular imaging with PET or SPECT has been an important research tool in psychiatry for as long as these modalities have been available. Here, we discuss two areas of neuroimaging relevant to current psychiatry research. The first is the use of imaging to study neurotransmission. We discuss the use of pharmacologic probes to induce changes in levels of neurotransmitters that can be inferred through their effects on outcome measures of imaging experiments, from their historical origins focusing on dopamine transmission through recent developments involving serotonin, GABA, and glutamate. Next, we examine imaging of neuroinflammation in the context of psychiatry. Imaging markers of neuroinflammation have been studied extensively in other areas of brain research, but they have more recently attracted interest in psychiatry research, based on accumulating evidence that there may be an inflammatory component to some psychiatric conditions. Furthermore, new probes are under development that would allow unprecedented insights into cellular processes. In summary, molecular imaging would continue to offer great potential as a unique tool to further our understanding of brain function in health and disease.
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Affiliation(s)
- Mark Slifstein
- Department of Psychiatry, Columbia University Medical Center, New York, NY; New York State Psychiatric Institute, New York, NY; Department of Psychiatry, Stony Brook University, New York, NY.
| | - Anissa Abi-Dargham
- Department of Psychiatry, Columbia University Medical Center, New York, NY; Department of Radiology, Columbia University Medical Center, New York, NY; New York State Psychiatric Institute, New York, NY; Department of Psychiatry, Stony Brook University, New York, NY
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19
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Al-Sweidi S, Morissette M, Di Paolo T. Estrogen receptors modulate striatal metabotropic receptor type 5 in intact and MPTP male mice model of Parkinson's disease. J Steroid Biochem Mol Biol 2016; 161:84-91. [PMID: 26873133 DOI: 10.1016/j.jsbmb.2016.02.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 12/23/2015] [Accepted: 02/07/2016] [Indexed: 01/17/2023]
Abstract
Glutamate is the most important brain excitatory neurotransmitter and glutamate overactivity is well documented in Parkinson's disease (PD). Metabotropic glutamate (mGlu) receptors are reported to interact with membrane estrogen receptors (ERs) and more specifically the mGlu5 receptor subtype. 17β-estradiol and mGlu5 antagonists have neuroprotective effects in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD. We previously reported that ERα and ERβ are involved in neuroprotection following MPTP toxicity. The present study investigated the implication of ERs on the mGlu5 receptor adaptive response to MPTP toxicity in the brain of wild type (WT), ER knockout (ERKO)α and ERKOβ male mice. Autoradiography of [(3)H]ABP688 specific binding to striatal mGlu5 receptors showed a dorsal/ventral gradient similar for WT, ERKOα and ERKOβ mice with higher values ventrally. The lateral septum had highest [(3)H]ABP688 specific binding that remained unchanged in all experimental groups. ERKOα and ERKOβ mice had similarly lower striatal [(3)H]ABP688 specific binding than WT mice as measured also by Western blots. MPTP dose-dependently decreased striatal [(3)H]ABP688 specific binding in WT but not in ERKOα and ERKOβ mice; this correlated positively with striatal dopamine concentrations. A 17β-estradiol treatment for 10 days left unchanged striatal [(3)H]ABP688 specific binding of unlesioned mice of the three genotypes. 17β-estradiol treatment for 5 days before MPTP and for 5 days after partially prevented the mGlu5 receptor decrease only in WT MPTP mice and this was associated with higher BDNF striatal contents. These results thus show that in male mice ERs affect striatal mGlu5 receptor levels and their response to MPTP.
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MESH Headings
- 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine
- Animals
- Brain-Derived Neurotrophic Factor/metabolism
- Corpus Striatum/metabolism
- Corpus Striatum/pathology
- Disease Models, Animal
- Estradiol/metabolism
- Estrogen Receptor alpha/genetics
- Estrogen Receptor alpha/metabolism
- Estrogen Receptor beta/genetics
- Estrogen Receptor beta/metabolism
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Parkinson Disease, Secondary/genetics
- Parkinson Disease, Secondary/metabolism
- Parkinson Disease, Secondary/pathology
- Receptor, Metabotropic Glutamate 5/analysis
- Receptor, Metabotropic Glutamate 5/metabolism
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Affiliation(s)
- S Al-Sweidi
- Neuroscience Research Unit, Centre Hospitalier Universitaire de Québec, CHUL, Quebec City, Quebec G1V 4G2, Canada; Faculty of Pharmacy, Laval University, Quebec City, Quebec G1K 7P4, Canada
| | - M Morissette
- Neuroscience Research Unit, Centre Hospitalier Universitaire de Québec, CHUL, Quebec City, Quebec G1V 4G2, Canada
| | - T Di Paolo
- Neuroscience Research Unit, Centre Hospitalier Universitaire de Québec, CHUL, Quebec City, Quebec G1V 4G2, Canada; Faculty of Pharmacy, Laval University, Quebec City, Quebec G1K 7P4, Canada.
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20
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Auberson YP, Briard E, Sykes D, Reilly J, Healy M. Ligand Specific Efficiency (LSE) Index for PET Tracer Optimization. ChemMedChem 2016; 11:1415-27. [DOI: 10.1002/cmdc.201600112] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 04/13/2016] [Indexed: 11/08/2022]
Affiliation(s)
- Yves P. Auberson
- Novartis Institutes for BioMedical Research; Klybeckstrasse 141 4057 Basel Switzerland
| | - Emmanuelle Briard
- Novartis Institutes for BioMedical Research; Klybeckstrasse 141 4057 Basel Switzerland
| | - David Sykes
- University of Nottingham; Cell Signalling Department; Nottingham NG7 2RD UK
| | - John Reilly
- Novartis Institutes for BioMedical Research; 250 Massachusetts Avenue Cambridge MA 02139 USA
| | - Mark Healy
- Novartis Institutes for BioMedical Research; 250 Massachusetts Avenue Cambridge MA 02139 USA
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21
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Fuxe K, Borroto-Escuela DO. Basimglurant for treatment of major depressive disorder: a novel negative allosteric modulator of metabotropic glutamate receptor 5. Expert Opin Investig Drugs 2015. [DOI: 10.1517/13543784.2015.1074175] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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22
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Lindemann L, Porter RH, Scharf SH, Kuennecke B, Bruns A, von Kienlin M, Harrison AC, Paehler A, Funk C, Gloge A, Schneider M, Parrott NJ, Polonchuk L, Niederhauser U, Morairty SR, Kilduff TS, Vieira E, Kolczewski S, Wichmann J, Hartung T, Honer M, Borroni E, Moreau JL, Prinssen E, Spooren W, Wettstein JG, Jaeschke G. Pharmacology of Basimglurant (RO4917523, RG7090), a Unique Metabotropic Glutamate Receptor 5 Negative Allosteric Modulator in Clinical Development for Depression. J Pharmacol Exp Ther 2015; 353:213-33. [DOI: 10.1124/jpet.114.222463] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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23
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Kim JY, Son MH, Choi K, Baek DJ, Ko MK, Lim EJ, Pae AN, Keum G, Lee JK, Cho YS, Choo H, Lee YW, Moon BS, Lee BC, Lee HY, Min SJ. Synthesis and In vivo Evaluation of 5-Methoxy-2-(phenylethynyl)quinoline (MPEQ) and [11C]MPEQ Targeting Metabotropic Glutamate Receptor 5 (mGluR5). B KOREAN CHEM SOC 2014. [DOI: 10.5012/bkcs.2014.35.8.2304] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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24
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Janssen B, Vugts DJ, Funke U, Spaans A, Schuit RC, Kooijman E, Rongen M, Perk LR, Lammertsma AA, Windhorst AD. Synthesis and initial preclinical evaluation of the P2X7 receptor antagonist [¹¹C]A-740003 as a novel tracer of neuroinflammation. J Labelled Comp Radiopharm 2014; 57:509-16. [PMID: 24995673 DOI: 10.1002/jlcr.3206] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Revised: 04/09/2014] [Accepted: 04/11/2014] [Indexed: 11/10/2022]
Abstract
Neuroinflammation, in particular activation of microglia, is thought to play an important role in the progression of neurodegenerative diseases. In activated microglia, the purinergic P2X7 receptor is upregulated. A-740003, a highly affine and selective P2X7 receptor antagonist, is a promising candidate for the development of a radiotracer for imaging of neuroinflammation by positron emission tomography. For this purpose, [(11)C]A-740003 was synthesised and evaluated in vivo with respect to both tracer metabolism and biodistribution. In plasma, a moderate metabolic rate was seen. In healthy rat brain, only marginal uptake of [(11)C]A-740003 was observed and, therefore, metabolites in brain could not be determined. Whether the minimal brain uptake is due to the low expression levels of the P2X7 receptor in healthy brain or to limited transport across the blood-brain barrier has yet to be elucidated.
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Affiliation(s)
- Bieneke Janssen
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
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25
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Decrease of mGluR5 receptor density goes parallel with changes in enkephalin and substance P immunoreactivity in Huntington's disease: a preliminary investigation in the postmortem human brain. Brain Struct Funct 2014; 220:3043-51. [PMID: 24969128 DOI: 10.1007/s00429-014-0812-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Accepted: 05/26/2014] [Indexed: 12/24/2022]
Abstract
Group 1 metabotropic glutamate subtype 5 receptors (mGluR5) contribute to the control of motor behavior by regulating the balance between excitation and inhibition of outputs in the basal ganglia. The density of these receptors is increased in patients with Parkinson's disease and motor complications. We hypothesized that similar changes may occur in Huntington's disease (HD) and aimed at testing this hypothesis in a preliminary experimental series in postmortem human brain material obtained from HD patients. Using autoradiography, we analyzed mGluR5 density in the putamen, caudate nucleus and cerebellum (control region) in postmortem tissue samples from three patients with HD and three controls with two mGluR5-specific radioligands ([(3)H]ABP688 and [(11)C]ABP688). The density of enkephalin (Enk)- or substance P (SP)-containing neurons was assessed using immunohistochemical and cell-counting methods. [(3)H]ABP688 binding in HD was reduced in the caudate (-70.4 %, P < 0.001), in the putamen (-33.3 %, P = 0.053), and in the cerebellum (-8.79 %, P = 0.930) vs controls. Results with [(11)C]ABP688 were similar; there was good correlation between [(11)C]ABP688 and [(3)H]ABP688 binding ratios. Total cell density was similar in all three brain regions in HD patients and controls. Neuronal density was 69 % lower in the caudate (P = 0.002) and 64 % lower in the putamen (P < 0.001) of HD patients vs controls. Both direct and indirect pathways were affected, with ≥ 90 % decrease in the density of Enk- and SP-containing neurons in the caudate and putamen of HD patients vs controls (P < 0.001). In contrast to earlier observations in PD, in HD, compared to controls, the mGluR5 density was significantly lower in the caudate nucleus. The decrease in neuronal density suggests that neuronal loss was largely responsible for the observed decrease in mGluR5.
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Pomierny-Chamioło L, Rup K, Pomierny B, Niedzielska E, Kalivas PW, Filip M. Metabotropic glutamatergic receptors and their ligands in drug addiction. Pharmacol Ther 2014; 142:281-305. [DOI: 10.1016/j.pharmthera.2013.12.012] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 12/02/2013] [Indexed: 02/07/2023]
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Milella MS, Marengo L, Larcher K, Fotros A, Dagher A, Rosa-Neto P, Benkelfat C, Leyton M. Limbic system mGluR5 availability in cocaine dependent subjects: a high-resolution PET [(11)C]ABP688 study. Neuroimage 2014; 98:195-202. [PMID: 24795154 DOI: 10.1016/j.neuroimage.2014.04.061] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 03/25/2014] [Accepted: 04/22/2014] [Indexed: 12/13/2022] Open
Abstract
Cocaine self-administration decreases type 5 metabotropic glutamate receptor (mGluR5) tissue concentrations in laboratory rats during early abstinence. These changes are thought to influence the drug's reinforcing properties and the ability of drug-related cues to induce relapse. Here, our goal was to measure brain regional mGluR5 availability in recently abstinent cocaine dependent humans. Participants meeting DSM-IV diagnostic criteria for current cocaine dependence (n=9) were recruited from the general population. mGluR5 availability (binding potential, non-displaceable; BPND) was measured with high-resolution positron emission tomography (PET HRRT) and [(11)C]ABP688. Compared to age- and sex-matched healthy controls (n=9), cocaine dependent subjects showed significantly lower BPND values in the ventral (bilateral: -28.2%, p=0.011), associative (right: -21.4%, p=0.043), and sensorimotor striatum (bilateral: -21.7%, p=0.045), amygdala (left: -26%, p=0.046) and insula (right: -23.3%, p=0.041). Among the cocaine users, receptor availabilities were related to abstinence (range: 2 to 14days). The longer the duration of abstinence, the lower the BPND values in the sensorimotor striatum (r=-0.71, p=0.034), left amygdala (r=-0.73, p=0.026) and right insula (r=-0.67, p=0.046). Compared to healthy controls, BPND values were significantly reduced in those who tested negative for cocaine on the PET test session in the ventral (p=0.018) and sensorimotor striatum (p=0.017), left amygdala (p=0.008), and right insula (p=0.029), but not in those who tested positive. Together, these results provide evidence of time-related mGluR5 alterations in striatal and limbic regions in humans during early cocaine abstinence.
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Affiliation(s)
- M S Milella
- Department of Psychiatry, McGill University, Montreal H3A 1A1, Canada
| | - L Marengo
- Department of Psychiatry, McGill University, Montreal H3A 1A1, Canada
| | - K Larcher
- Department of Neurology & Neurosurgery, Montreal Neurological Institute, McGill University, Montreal H3A 2B4, Canada
| | - A Fotros
- Department of Psychiatry, McGill University, Montreal H3A 1A1, Canada
| | - A Dagher
- Department of Neurology & Neurosurgery, Montreal Neurological Institute, McGill University, Montreal H3A 2B4, Canada
| | - P Rosa-Neto
- Translational Neuroimaging Laboratory, Douglas Research Institute, Montreal H4H 1R3, Canada
| | - C Benkelfat
- Department of Psychiatry, McGill University, Montreal H3A 1A1, Canada; Department of Neurology & Neurosurgery, Montreal Neurological Institute, McGill University, Montreal H3A 2B4, Canada
| | - M Leyton
- Department of Psychiatry, McGill University, Montreal H3A 1A1, Canada; Department of Neurology & Neurosurgery, Montreal Neurological Institute, McGill University, Montreal H3A 2B4, Canada; Center for Studies in Behavioral Neurobiology, Concordia University, Montreal H4B 1R6, Canada.
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Schmidt F, George P, Sapi J. Chemical biology: contribution to molecular therapeutic innovation--a new role for chemistry? Report from the thematic symposium organized by the SCT (French Medicinal Chemistry Society), November 26th, 2013. ACS Chem Biol 2014; 9:849-52. [PMID: 24742389 DOI: 10.1021/cb500173s] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Frédéric Schmidt
- SCT Communication Officer; Institut Curie, Research Center, CNRS UMR3666, INSERM U1143, 26 rue d’Ulm, F-75248 Paris, France
| | - Pascal George
- SCT President,
Independent Scientific
Expert and Adviser
| | - Janos Sapi
- SCT Vice-President; UMR CNRS 7312, Université de Reims-Champagne-Ardenne, 51 rue Cognacq-Jay, F- 51096 Reims cedex, France
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Michalon A, Bruns A, Risterucci C, Honer M, Ballard TM, Ozmen L, Jaeschke G, Wettstein JG, von Kienlin M, Künnecke B, Lindemann L. Chronic metabotropic glutamate receptor 5 inhibition corrects local alterations of brain activity and improves cognitive performance in fragile X mice. Biol Psychiatry 2014; 75:189-97. [PMID: 23910948 DOI: 10.1016/j.biopsych.2013.05.038] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Revised: 05/22/2013] [Accepted: 05/24/2013] [Indexed: 12/28/2022]
Abstract
BACKGROUND Fragile X syndrome (FXS) is the most common genetic cause for intellectual disability. Fmr1 knockout (KO) mice are an established model of FXS. Chronic pharmacological inhibition of metabotropic glutamate receptor 5 (mGlu5) in these mice corrects multiple molecular, physiological, and behavioral phenotypes related to patients' symptoms. To better understand the pathophysiology of FXS and the effect of treatment, brain activity was analyzed using functional magnetic resonance imaging in relation to learning and memory performance. METHODS Wild-type (WT) and Fmr1 KO animals receiving chronic treatment with the mGlu5 inhibitor CTEP or vehicle were evaluated consecutively for 1) learning and memory performance in the inhibitory avoidance and extinction test, and 2) for the levels of brain activity using continuous arterial spin labeling based functional magnetic resonance imaging. Neural activity patterns were correlated with cognitive performance using a multivariate regression analysis. Furthermore, mGlu5 receptor expression in brains of untreated mice was analyzed by autoradiography and saturation analysis using [(3)H]-ABP688. RESULTS Chronic CTEP treatment corrected the learning deficit observed in Fmr1 KO mice in the inhibitory avoidance and extinction test and prevented memory extinction in WT and Fmr1 KO animals. Chronic CTEP treatment normalized perfusion in the amygdala and the lateral hypothalamus in Fmr1 KO mice and furthermore decreased perfusion in the hippocampus and increased perfusion in primary sensorimotor cortical areas. No significant differences in mGlu5 receptor expression levels between Fmr1 WT and KO mice were detected. CONCLUSIONS Chronic mGlu5 inhibition corrected the learning deficits and partially normalized the altered brain activity pattern in Fmr1 KO mice.
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Affiliation(s)
- Aubin Michalon
- Discovery Neuroscience, F. Hoffmann-La Roche AG, Pharma Research & Early Development, Basel
| | - Andreas Bruns
- Discovery Neuroscience, F. Hoffmann-La Roche AG, Pharma Research & Early Development, Basel
| | - Céline Risterucci
- Discovery Neuroscience, F. Hoffmann-La Roche AG, Pharma Research & Early Development, Basel
| | - Michael Honer
- Discovery Neuroscience, F. Hoffmann-La Roche AG, Pharma Research & Early Development, Basel
| | - Theresa M Ballard
- Discovery Neuroscience, F. Hoffmann-La Roche AG, Pharma Research & Early Development, Basel
| | - Laurence Ozmen
- Discovery Neuroscience, F. Hoffmann-La Roche AG, Pharma Research & Early Development, Basel
| | - Georg Jaeschke
- Discovery Chemistry, F. Hoffmann-La Roche AG, Pharma Research & Early Development, Basel; and Neurimmune Holding AG, Schlieren, Switzerland
| | - Joseph G Wettstein
- Discovery Neuroscience, F. Hoffmann-La Roche AG, Pharma Research & Early Development, Basel
| | - Markus von Kienlin
- Discovery Neuroscience, F. Hoffmann-La Roche AG, Pharma Research & Early Development, Basel
| | - Basil Künnecke
- Discovery Neuroscience, F. Hoffmann-La Roche AG, Pharma Research & Early Development, Basel
| | - Lothar Lindemann
- Discovery Neuroscience, F. Hoffmann-La Roche AG, Pharma Research & Early Development, Basel.
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Holland JP, Liang SH, Rotstein BH, Collier TL, Stephenson NA, Greguric I, Vasdev N. Alternative approaches for PET radiotracer development in Alzheimer's disease: imaging beyond plaque. J Labelled Comp Radiopharm 2013; 57:323-31. [PMID: 24327420 DOI: 10.1002/jlcr.3158] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Accepted: 10/29/2013] [Indexed: 12/18/2022]
Abstract
Alzheimer's disease (AD) and related dementias show increasing clinical prevalence, yet our understanding of the etiology and pathobiology of disease-related neurodegeneration remains limited. In this regard, noninvasive imaging with radiotracers for positron emission tomography (PET) presents a unique tool for quantifying spatial and temporal changes in characteristic biological markers of brain disease and for assessing potential drug efficacy. PET radiotracers targeting different protein markers are being developed to address questions pertaining to the molecular and/or genetic heterogeneity of AD and related dementias. For example, radiotracers including [(11) C]-PiB and [(18) F]-AV-45 (Florbetapir) are being used to measure the density of Aβ-plaques in AD patients and to interrogate the biological mechanisms of disease initiation and progression. Our focus is on the development of novel PET imaging agents, targeting proteins beyond Aβ-plaques, which can be used to investigate the broader mechanism of AD pathogenesis. Here, we present the chemical basis of various radiotracers which show promise in preclinical or clinical studies for use in evaluating the phenotypic or biochemical characteristics of AD. Radiotracers for PET imaging neuroinflammation, metal ion association with Aβ-plaques, tau protein, cholinergic and cannabinoid receptors, and enzymes including glycogen-synthase kinase-3β and monoamine oxidase B amongst others, and their connection to AD are highlighted.
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Affiliation(s)
- Jason P Holland
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, Department of Radiology, Harvard Medical School, 55 Fruit St., White 427, Boston, Massachusetts, 02114, USA; Life Sciences, Australian Nuclear Science and Technology Organisation, Kirrawee, New South Wales, 2232, Australia
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Kawamura K, Yamasaki T, Kumata K, Furutsuka K, Takei M, Wakizaka H, Fujinaga M, Kariya K, Yui J, Hatori A, Xie L, Shimoda Y, Hashimoto H, Hayashi K, Zhang MR. Binding potential of (E)-[¹¹C]ABP688 to metabotropic glutamate receptor subtype 5 is decreased by the inclusion of its ¹¹C-labelled Z-isomer. Nucl Med Biol 2013; 41:17-23. [PMID: 24183615 DOI: 10.1016/j.nucmedbio.2013.09.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 09/24/2013] [Accepted: 09/28/2013] [Indexed: 01/15/2023]
Abstract
INTRODUCTION [(11)C]ABP688 is a promising positron emission tomography (PET) ligand for imaging of metabotropic glutamate receptor subtype 5 (mGlu5 receptor). Of the two geometric isomers of ABP688, (E)-ABP688 has a greater affinity towards mGlu5 receptors than (Z)-ABP688. Therefore, a high ratio of E-isomer is required when using [(11)C]ABP688 as a PET probe for imaging and quantification of mGlu5 receptors. The aim of this study was to evaluate the effect (Z)-[(11)C]ABP688 on the synthesis of [(11)C]ABP688 to be used for binding (E)-[(11)C]ABP688 in the brain. METHODS We synthesized and separated (E)- and (Z)-[(11)C]ABP688 by purification using an improved preparative high-performance liquid chromatography (HPLC) method equipped with a COSMOSIL Cholester column. We performed an in vitro binding assay in rat brain homogenates and PET studies of the rat brains using (E)- and (Z)-[(11)C]ABP688. RESULTS (E)- and (Z)-[(11)C]ABP688 were successfully obtained with suitable radioactivity for application. In the in vitro assay, the Kd value of (E)-[(11)C]ABP688 (5.7 nmol/L) was higher than that of (Z)-[(11)C]ABP688 (140 nmol/L). In the PET study of the rat brain, high radioactivity after injection of (E)-[(11)C]ABP688 was observed in regions rich in mGlu5 receptors such as the striatum and hippocampus. In contrast, after injection of (Z)-[(11)C]ABP688, radioactivity did not accumulate in the brain. Furthermore, BPND in the striatum and hippocampus was highly correlated (R(2) = 0.99) with the percentage of (E)-[(11)C]ABP688 of the total radioactivity of (E)- and (Z)-[(11)C]ABP688 in the injection. CONCLUSION We demonstrated that including (Z)-[(11)C]ABP688 in the [(11)C]ABP688 injection can decrease BPND in regions rich in mGlu5 receptors. Routine production of (E)-[(11)C]ABP688 will be helpful for imaging and quantification of mGlu5 receptors in clinical studies.
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Affiliation(s)
- Kazunori Kawamura
- Molecular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555, Japan.
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Morin N, Morissette M, Grégoire L, Gomez-Mancilla B, Gasparini F, Di Paolo T. Chronic treatment with MPEP, an mGlu5 receptor antagonist, normalizes basal ganglia glutamate neurotransmission in L-DOPA-treated parkinsonian monkeys. Neuropharmacology 2013; 73:216-31. [PMID: 23756168 DOI: 10.1016/j.neuropharm.2013.05.028] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Revised: 05/17/2013] [Accepted: 05/18/2013] [Indexed: 10/26/2022]
Abstract
Metabotropic glutamate 5 (mGlu5) receptor antagonists reduce L-3,4-dihydroxyphenylalanine (L-DOPA)-induced dyskinesias (LID) in Parkinson's disease (PD). The aim of this study was to investigate the long-term effect of the prototypal mGlu5 receptor antagonist 2-methyl-6-(phenylethynyl)pyridine (MPEP) on glutamate receptors known to be involved in the development of LID in the de novo chronic treatment of monkeys lesioned with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). MPTP monkeys were treated for one month with L-DOPA and developed dyskinesias while those treated with L-DOPA and MPEP (10 mg/kg) developed significantly less. Normal control and saline-treated MPTP monkeys were also included. All MPTP monkeys were extensively and similarly denervated. The basal ganglia [(3)H]ABP688 specific binding (mGlu5 receptors) was elevated in L-DOPA-treated MPTP monkeys compared to controls but not in those treated with L-DOPA and MPEP; dyskinesia scores of these monkeys correlated positively with their [(3)H]ABP688 specific binding. Striatal density (B(max)) of [(3)H]ABP688 specific binding increased in L-DOPA-treated MPTP monkeys compared to other groups and affinity (Kd) remained unchanged. Striatal mGlu5 receptor mRNA remained unchanged following treatments. Elevated basal ganglia specific binding of [(3)H]Ro 25-6981 (NMDA NR1/NR2B receptors), [(3)H]Ro 48-8587 (AMPA receptors) but not [(3)H]CGP-39653 (NMDA NR1/NR2A receptors) was observed only in L-DOPA-treated MPTP monkeys; dyskinesias scores correlated with binding. By contrast, basal ganglia [(3)H]LY341495 specific binding (mGlu2/3 receptors) decreased in L-DOPA-treated MPTP monkeys compared to controls, saline and L-DOPA + MPEP treated MPTP monkeys; dyskinesias scores correlated negatively with this binding. Hence, chronic MPEP treatment reduces the development of LID and is associated with a normalization of glutamate neurotransmission.
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Affiliation(s)
- Nicolas Morin
- Neuroscience Research Unit, Laval University Medical Center (CHUQ), Quebec, QC, Canada
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Kågedal M, Cselényi Z, Nyberg S, Raboisson P, Ståhle L, Stenkrona P, Varnäs K, Halldin C, Hooker AC, Karlsson MO. A positron emission tomography study in healthy volunteers to estimate mGluR5 receptor occupancy of AZD2066 - estimating occupancy in the absence of a reference region. Neuroimage 2013; 82:160-9. [PMID: 23668965 DOI: 10.1016/j.neuroimage.2013.05.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2012] [Revised: 04/29/2013] [Accepted: 05/06/2013] [Indexed: 11/27/2022] Open
Abstract
AZD2066 is a new chemical entity pharmacologically characterized as a selective, negative allosteric modulator of the metabotropic glutamate receptor subtype 5 (mGluR5). Antagonism of mGluR5 has been implicated in relation to various diseases such as anxiety, depression, and pain disorders. To support translation from preclinical results and previous experiences with this target in man, a positron emission tomography study was performed to estimate the relationship between AZD2066 plasma concentrations and receptor occupancy in the human brain, using the mGluR5 radioligand [(11)C]-ABP688. The study involved PET scans on 4 occasions in 6 healthy volunteers. The radioligand was given as a tracer dose alone and following oral treatment with different doses of AZD2066. The analysis was based on the total volume of distribution derived from each PET-assessment. A non-linear mixed effects model was developed where ten delineated brain regions of interest from all PET scans were included in one simultaneous fit. For comparison the analysis was also performed according to a method described previously by Lassen et al. (1995). The results of the analysis showed that the total volume of distribution decreased with increasing drug concentrations in all regions with an estimated Kipl of 1170 nM. Variability between individuals and occasions in non-displaceable volume of distribution could explain most of the variability in the total volume of distribution. The Lassen approach provided a similar estimate for Kipl, but the variability was exaggerated and difficult to interpret.
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Sobrio F. Radiosynthesis of carbon-11 and fluorine-18 labelled radiotracers to image the ionotropic and metabotropic glutamate receptors. J Labelled Comp Radiopharm 2013; 56:180-6. [DOI: 10.1002/jlcr.2995] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 08/28/2012] [Accepted: 11/06/2012] [Indexed: 01/28/2023]
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Sandiego CM, Nabulsi N, Lin SF, Labaree D, Najafzadeh S, Huang Y, Cosgrove K, Carson RE. Studies of the metabotropic glutamate receptor 5 radioligand [¹¹C]ABP688 with N-acetylcysteine challenge in rhesus monkeys. Synapse 2013; 67:489-501. [PMID: 23424090 DOI: 10.1002/syn.21656] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Accepted: 02/12/2013] [Indexed: 02/05/2023]
Abstract
Detecting changes in receptor binding at the metabotropic glutamate receptor 5 (mGluR5) with the PET allosteric antagonist, [¹¹C]ABP688, may be valuable for studying dysfunctional glutamate transmission associated with psychiatric illnesses. This study was designed to validate the findings of a recent pilot study in baboons which reported a significant global decrease from baseline [¹¹C]ABP688 binding after increasing endogenous glutamate with 50 mg/kg N-acetylcysteine (NAC), with no change from test to retest. In rhesus monkeys (n = 5), paired [¹¹C]ABP688 scans were performed on the same day on the Focus-220 as follows (n = 3 per group): test-retest, baseline-NAC (50 mg/kg), and baseline-NAC (100 mg/kg). Multiple modeling methods were evaluated for kinetic analysis to estimate the total volume of distribution (VT ) and non-displaceable binding potential (BP(ND)) in regions-of-interest (ROIs), with the cerebellum gray matter (CGM) as the reference region. There was an increasing trend from test to retest BP(ND) across ROIs (13%). NAC (50 mg/kg and 100 mg/kg) increased VT (5% and 19%) and decreased BP(ND) (3% and 10%), respectively, significant only for VT in ROIs at the 100 mg/kg dose. High intersubject variability in BP(ND) was comparable to that reported in the baboon study. However, interpretability of BP(ND) is difficult with increases in VT in the CGM reference region at the higher NAC dose. Additionally, the net reduction in BP(ND) from the baseline-NAC scans may be obscured due to observed increases in test-retest BP(ND). Thus, we did not strictly replicate the findings in the baboon study based on BP(ND).
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Affiliation(s)
- Christine M Sandiego
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut 06520, 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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Zysk JR, Spear N, Fieles W, Stein MM, Sygowski LS, King MM, Hoesch V, Hastings R, Brockel B, Do M, Ström P, Gadient R, Chhajlani V, Elmore CS, Maier DL. In vitro binding of a radio-labeled positive allosteric modulator for metabotropic glutamate receptor subtype 5. Synapse 2012; 67:135-44. [PMID: 23150216 DOI: 10.1002/syn.21625] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2012] [Accepted: 11/06/2012] [Indexed: 12/21/2022]
Abstract
The positive allosteric modulator (PAM) binding site for metabotropic glutamate receptor subtype 5 (mGlu(5)) lacks a readily available radio-labeled tracer fordetailed structure-activity studies. This communication describes a selective mGlu(5) compound, 7-methyl-2-(4-(pyridin-2-yloxy)benzyl)-5-(pyridin-3-yl)isoindolin-1-one (PBPyl) that binds with high affinity to human mGlu(5) and exhibits functional PAM activity. Analysis of PBPyl by FLIPR revealed an EC(50) of 87 nM with an 89% effect in transfected HEK293 cells and an EC(50) of 81 nM with a 42% effect in rat primary neurons. PBPyl exhibited 5-fold higher functional selectivity for mGlu(5) in a full mGlu receptor panel. Unlabeled PBPyl was tested for specific binding using a liquid chromatography mass spectrometry (LC/MS/MS)-based filtration binding assay and exhibited 40% specific binding in recombinant membranes, a value higher than any candidate compound tested. In competition binding studies with [(3)H]MPEP, the mGlu(5) receptor negative allosteric modulator (NAM), PBPyl exhibited a k(i) value of 34 nM. PBPyl also displaced [(3)H]ABP688, a mGluR(5) receptor NAM, in tissue sections from mouse and rat brain using autoradiography. Areas of specific binding included the frontal cortex, striatum and nucleus accumbens. PBPyl was radiolabeled to a specific activity of 15 Ci/mmol and tested for specific binding in a filter plate format. In recombinant mGlu(5b) membranes, [(3)H] PBPyl exhibited saturable binding with a K(d) value of 18.6 nM. In competition binding experiments, [(3)H] PBPyl was displaced by high affinity mGlu(5) positive and negative modulators. Further tests showed that PBPyl displays less than optimal characteristics as an in vivo tool, including a high volume of distribution and ClogP, making it more suitable as an in vitro compound. However, as a first report of direct binding of an mGlu(5) receptor PAM, this study offers value toward the development of novel PET imaging agents for this important therapeutic target.
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Affiliation(s)
- John R Zysk
- AstraZeneca Pharmaceuticals, Department of Neuroscience, CNS R&D, Wilmington, Delaware, USA
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Discovery of 1H-pyrrolo[2,3-c]pyridine-7-carboxamides as novel, allosteric mGluR5 antagonists. Bioorg Med Chem Lett 2012; 22:6454-9. [DOI: 10.1016/j.bmcl.2012.08.053] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Revised: 08/10/2012] [Accepted: 08/13/2012] [Indexed: 11/21/2022]
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Milicevic Sephton S, Mu L, Schweizer WB, Schibli R, Krämer SD, Ametamey SM. Synthesis and evaluation of novel α-fluorinated (E)-3-((6-methylpyridin-2-yl)ethynyl)cyclohex-2-enone-O-methyl oxime (ABP688) derivatives as metabotropic glutamate receptor subtype 5 PET radiotracers. J Med Chem 2012; 55:7154-62. [PMID: 22822714 DOI: 10.1021/jm300648b] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
In the search for an optimal fluorine-18-labeled positron emission tomography (PET) radiotracer for imaging metabotropic glutamate receptor subtype 5 (mGluR5), we have prepared a series of five α-fluorinated derivatives based on the ABP688 structural manifold by application of a two-step enolization/NFSI α-fluorination method. Their binding affinities were evaluated in vitro, and the most promising candidate (Z)-16 exhibited a K(i) of 5.7 nM and a clogP value of 2.3. The synthesis of the precursor tosylate (E)-22 revealed a preference for the (E)-configurational isomer (K(i) = 31.2 nM), and successful radiosynthesis afforded (E)-[(18)F]-16 which was used as a model PET tracer to establish plasma and PBS stability. (E)-[(18)F]-16 (K(d) = 70 nM) exhibited excellent specificity for mGluR5 in autoradiographic studies on horizontal rat brain slices in vitro.
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Affiliation(s)
- Selena Milicevic Sephton
- Center for Radiopharmaceutical Sciences of ETH, PSI and USZ, Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology (ETH) Zurich, Wolfgang-Pauli Strasse 10, 8093 Zurich, Switzerland
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Morin N, Grégoire L, Morissette M, Desrayaud S, Gomez-Mancilla B, Gasparini F, Di Paolo T. MPEP, an mGlu5 receptor antagonist, reduces the development of L-DOPA-induced motor complications in de novo parkinsonian monkeys: biochemical correlates. Neuropharmacology 2012; 66:355-64. [PMID: 22884464 DOI: 10.1016/j.neuropharm.2012.07.036] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Revised: 07/06/2012] [Accepted: 07/09/2012] [Indexed: 10/28/2022]
Abstract
L-3,4-Dihydroxyphenylalanine (l-DOPA), the gold standard therapy for Parkinson disease (PD), is associated with motor fluctuations and dyskinesias. This study sought to prevent the development of l-DOPA-induced dyskinesias (LID) with the metabotropic glutamate receptor type 5 (mGlu5 receptor) antagonist 2-methyl-6-(phenylethynyl)pyridine (MPEP) in the de novo treatment of monkeys lesioned with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) as a PD model. MPTP-lesioned monkeys were treated once daily for one month with either l-DOPA or l-DOPA + MPEP (10 mg/kg). MPEP (administered 15 min before l-DOPA) plasma concentrations were elevated during all the l-DOPA motor activation and did not accumulate during a month. The antiparkinsonian effect was maintained throughout the treatment period in MPTP-lesioned monkeys treated with l-DOPA + MPEP, while the duration of this effect decreased over time in MPTP-lesioned monkeys treated with l-DOPA alone, suggesting wearing-off. Over the month-long treatment, the mean dyskinesia score increased in l-DOPA-treated monkeys; interestingly, this increase was reduced by overall 72% in the l-DOPA + MPEP group. Mean dyskinesia scores of monkeys correlated inversely with plasma MPEP concentrations. Normal control and saline-treated MPTP-lesioned monkeys were also included for biochemical analyses. All MPTP-lesioned monkeys were extensively and similarly denervated. [(3)H]ABP688 specific binding to mGlu5 receptors increased in the putamen of l-DOPA-treated monkeys compared to control, saline or l-DOPA + MPEP-treated monkeys. Mean dyskinesia scores of MPTP-lesioned monkeys correlated positively with [(3)H]ABP688 specific binding in the putamen. This study showed a beneficial chronic antidyskinetic effect of MPEP in de novol-DOPA-treated MPTP-lesioned monkeys, supporting the therapeutic use of mGlu5 receptor antagonists in PD to prevent LID. This article is part of a Special Issue entitled 'Metabotropic Glutamate Receptors'.
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Affiliation(s)
- Nicolas Morin
- Molecular Endocrinology and Genomic Research Center, Laval University Medical Center (CHUQ), Quebec, QC, Canada
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41
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Michalon A, Sidorov M, Ballard TM, Ozmen L, Spooren W, Wettstein JG, Jaeschke G, Bear MF, Lindemann L. Chronic pharmacological mGlu5 inhibition corrects fragile X in adult mice. Neuron 2012; 74:49-56. [PMID: 22500629 DOI: 10.1016/j.neuron.2012.03.009] [Citation(s) in RCA: 369] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/12/2012] [Indexed: 01/25/2023]
Abstract
Fragile X syndrome (FXS) is the most common form of inherited intellectual disability. Previous studies have implicated mGlu5 in the pathogenesis of the disease, but a crucial unanswered question is whether pharmacological mGlu5 inhibition is able to reverse an already established FXS phenotype in mammals. Here we have used the novel, potent, and selective mGlu5 inhibitor CTEP to address this issue in the Fmr1 knockout mouse. Acute CTEP treatment corrects elevated hippocampal long-term depression, protein synthesis, and audiogenic seizures. Chronic treatment that inhibits mGlu5 within a receptor occupancy range of 81% ± 4% rescues cognitive deficits, auditory hypersensitivity, aberrant dendritic spine density, overactive ERK and mTOR signaling, and partially corrects macroorchidism. This study shows that a comprehensive phenotype correction in FXS is possible with pharmacological intervention starting in young adulthood, after development of the phenotype. It is of great interest how these findings may translate into ongoing clinical research testing mGlu5 inhibitors in FXS patients.
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Affiliation(s)
- Aubin Michalon
- Discovery Neuroscience, Pharmaceuticals Division, F. Hoffmann-La Roche, CH-4070 Basel, Switzerland
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42
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Elmenhorst D, Aliaga A, Bauer A, Rosa-Neto P. Test-retest stability of cerebral mGluR₅ quantification using [¹¹C]ABP688 and positron emission tomography in rats. Synapse 2012; 66:552-60. [PMID: 22290765 DOI: 10.1002/syn.21542] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Accepted: 01/24/2012] [Indexed: 11/07/2022]
Abstract
This study evaluates the reproducibility of the quantification of metabotropic glutamate receptor type 5 (mGluR₅) densities in rats using the PET radiotracer [¹¹C]ABP688 and pharmacokinetic models that are based on an input function, which is derived from a reference tissue. Seven rats underwent dynamic PET scans (60 min) after bolus injection of [¹¹C]ABP688. Kinetic analyses included: binding potential (BP(ND) ) determined by calculating (a) the simplified reference tissue model (SRTM) and (b) its two-steps simplified version (SRTM2); (c) multilinear reference tissue model (MRTM) and (d) its 2-parameter version (MRTM2); (e) noninvasive graphical analysis (NIGA). Parametric images were generated representing BP(ND) by the MRTM2 model. BP(ND) determinations were reproducible with low to acceptable variability ranging from 5 to 10% and reproducibility scores (intraclass correlation coefficient) between 0.51 and 0.88. The pharmacokinetic model that showed lowest overall variability was the SRTM. In contrast, the use of the NIGA was associated with significantly lower reproducibility scores. Comparison of parametric images revealed no significant bias between test and retest measurements and is therefore suitable to compare groups at voxel levels. In conclusion, our results suggest that noninvasive quantification of [¹¹C]ABP688 imaging is reproducible and reliable for PET studies of the cerebral mGluR₅ in rats.
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Affiliation(s)
- David Elmenhorst
- Translational Neuroimaging Laboratory, McGill Center for Studies in Aging, Douglas Research Institute, Montreal, Quebec, Canada
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Kovačević T, Skelin I, Minuzzi L, Rosa-Neto P, Diksic M. Reduced metabotropic glutamate receptor 5 in the Flinders Sensitive Line of rats, an animal model of depression: an autoradiographic study. Brain Res Bull 2012; 87:406-12. [PMID: 22310150 DOI: 10.1016/j.brainresbull.2012.01.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2012] [Accepted: 01/18/2012] [Indexed: 01/15/2023]
Abstract
Depression is a brain disorder and there is still only a partial understanding of its underlying pathophysiology. Antidepressant medications with a fast onset have not yet been developed. In addition to the monoaminergic systems, the brain glutaminergic system has been implicated in the etiology of depression. Animal studies of depression have gained importance because they permit a more invasive manipulation of the subjects than human studies. In the present study, we measured the densities of the brain regional metabotropic glutaminergic receptor 5 (mGluR5) in the Flinders Sensitive Line (FSL) rat model of depression and two groups of control rats, the Flinders Resistant Line (FRL) and Sprague Dawley (SPD), the parent strain for both the FSL and FRL rats. The FSL rats showed lower densities of mGluR5 in many brain regions compared to either the SPD and/or FRL rats. In addition, the densities in the FRL rats were larger than in the SPD rats, suggesting possible problems in using FRL rats as controls. The presented data suggest that mGluR5 is lower in animal models of depression which could be related to the cognitive and emotional dysfunctions in the FSL rat model of depression and could be relevant to a better understanding of depression in humans.
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Affiliation(s)
- Tomislav Kovačević
- Cone Neurosurgical Research Laboratory, Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
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In vivo variation in metabotropic glutamate receptor subtype 5 binding using positron emission tomography and [11C]ABP688. J Cereb Blood Flow Metab 2011; 31:2169-80. [PMID: 21792244 PMCID: PMC3210337 DOI: 10.1038/jcbfm.2011.105] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The metabotropic glutamate receptor subtype 5 (mGluR5) has been implicated in the pathophysiology of mood and anxiety disorders. Recently, a positron emission tomography (PET) tracer exhibiting high selectivity and specificity for mGluR5, 3-(6-methyl-pyridin-2-ylethynyl)-cyclohex-2-enone-O-(11)C-methyl-oxime ([(11)C]ABP688), was developed. In this work, eight healthy adult male humans were imaged twice to assess within-subject [(11)C]ABP688 binding variability using PET. In seven of the eight subjects, significantly higher binding was observed during the second (retest) scan. This binding increase could not be definitively explained by differences in ligand injected mass or dose, or changes in metabolism between scans. In addition, this type of systematic binding increase was not observed in a [(11)C]ABP688 test-retest study performed by our group on anaesthetized baboons. It is therefore possible that the increased binding was because of physiological changes occurring between scans, such as changes in endogenous glutamate levels. If PET imaging with [(11)C]ABP688 could detect such differences, as preliminary evidence suggests, it could be used to help uncover the role of glutamate in the pathophysiology of brain disorders. However, regardless of its ability to detect endogenous glutamate differences, [(11)C]ABP688 binding variability could make accurate assessments of drug occupancy or group differences using this ligand difficult.
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Lindemann L, Jaeschke G, Michalon A, Vieira E, Honer M, Spooren W, Porter R, Hartung T, Kolczewski S, Büttelmann B, Flament C, Diener C, Fischer C, Gatti S, Prinssen EP, Parrott N, Hoffmann G, Wettstein JG. CTEP: a novel, potent, long-acting, and orally bioavailable metabotropic glutamate receptor 5 inhibitor. J Pharmacol Exp Ther 2011; 339:474-86. [PMID: 21849627 DOI: 10.1124/jpet.111.185660] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The metabotropic glutamate receptor 5 (mGlu5) is a glutamate-activated class C G protein-coupled receptor widely expressed in the central nervous system and clinically investigated as a drug target for a range of indications, including depression, Parkinson's disease, and fragile X syndrome. Here, we present the novel potent, selective, and orally bioavailable mGlu5 negative allosteric modulator with inverse agonist properties 2-chloro-4-((2,5-dimethyl-1-(4-(trifluoromethoxy)phenyl)-1H-imidazol-4-yl)ethynyl)pyridine (CTEP). CTEP binds mGlu5 with low nanomolar affinity and shows >1000-fold selectivity when tested against 103 targets, including all known mGlu receptors. CTEP penetrates the brain with a brain/plasma ratio of 2.6 and displaces the tracer [(3)H]3-(6-methyl-pyridin-2-ylethynyl)-cyclohex-2-enone-O-methyl-oxime (ABP688) in vivo in mice from brain regions expressing mGlu5 with an average ED(50) equivalent to a drug concentration of 77.5 ng/g in brain tissue. This novel mGlu5 inhibitor is active in the stress-induced hyperthermia procedure in mice and the Vogel conflict drinking test in rats with minimal effective doses of 0.1 and 0.3 mg/kg, respectively, reflecting a 30- to 100-fold higher in vivo potency compared with 2-methyl-6-(phenylethynyl)pyridine (MPEP) and fenobam. CTEP is the first reported mGlu5 inhibitor with both long half-life of approximately 18 h and high oral bioavailability allowing chronic treatment with continuous receptor blockade with one dose every 48 h in adult and newborn animals. By enabling long-term treatment through a wide age range, CTEP allows the exploration of the full therapeutic potential of mGlu5 inhibitors for indications requiring chronic receptor inhibition.
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Affiliation(s)
- Lothar Lindemann
- F. Hoffmann-La Roche Ltd. Pharmaceuticals Division, Discovery Neuroscience, Grenzacherstrasse 124, 4070 Basel, Switzerland.
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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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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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Urwyler S. Allosteric modulation of family C G-protein-coupled receptors: from molecular insights to therapeutic perspectives. Pharmacol Rev 2011; 63:59-126. [PMID: 21228259 DOI: 10.1124/pr.109.002501] [Citation(s) in RCA: 164] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Allosteric receptor modulation is an attractive concept in drug targeting because it offers important potential advantages over conventional orthosteric agonism or antagonism. Allosteric ligands modulate receptor function by binding to a site distinct from the recognition site for the endogenous agonist. They often have no effect on their own and therefore act only in conjunction with physiological receptor activation. This article reviews the current status of allosteric modulation at family C G-protein coupled receptors in the light of their specific structural features on the one hand and current concepts in receptor theory on the other hand. Family C G-protein-coupled receptors are characterized by a large extracellular domain containing the orthosteric agonist binding site known as the "venus flytrap module" because of its bilobal structure and the dynamics of its activation mechanism. Mutational analysis and chimeric constructs have revealed that allosteric modulators of the calcium-sensing, metabotropic glutamate and GABA(B) receptors bind to the seven transmembrane domain, through which they modify signal transduction after receptor activation. This is in contrast to taste-enhancing molecules, which bind to different parts of sweet and umami receptors. The complexity of interactions between orthosteric and allosteric ligands is revealed by a number of adequate biochemical and electrophysiological assay systems. Many allosteric family C GPCR modulators show in vivo efficacy in behavioral models for a variety of clinical indications. The positive allosteric calcium sensing receptor modulator cinacalcet is the first drug of this type to enter the market and therefore provides proof of principle in humans.
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Affiliation(s)
- Stephan Urwyler
- Department of Chemistry and Biochemistry, University of Berne, P/A Weissensteinweg 3, CH-3303 Jegenstorf, Berne, Switzerland.
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50
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Elmenhorst D, Minuzzi L, Aliaga A, Rowley J, Massarweh G, Diksic M, Bauer A, Rosa-Neto P. In vivo and in vitro validation of reference tissue models for the mGluR(5) ligand [(11)C]ABP688. J Cereb Blood Flow Metab 2010; 30:1538-49. [PMID: 20531460 PMCID: PMC2949244 DOI: 10.1038/jcbfm.2010.65] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The primary objective of this study was to verify the suitability of reference tissue-based quantification methods of the metabotropic glutamate receptor type 5 (mGluR(5)) with [(11)C]ABP688. This study presents in vivo (Positron Emission Tomography (PET)) and in vitro (autoradiography) measurements of mGluR(5) densities in the same rats and evaluates both noninvasive and blood-dependent pharmacokinetic models for the quantification of [(11)C]ABP688 binding. Eleven rats underwent [(11)C]ABP688 PET scans. In five animals, baseline scans were compared with blockade experiments with the antagonist 1,2-methyl-6-(phenylethynyl)-pyridine (MPEP), and arterial blood samples were drawn and corrected for metabolites. Afterward, saturation-binding autoradiography was performed. Blocking with MPEP resulted in an average decrease of the total distribution volume (V(T)) between 43% and 58% (thalamus and caudate-putamen, respectively) but had no significant effect on cerebellar V(T) (mean reduction: -0.01%). Comparing binding potential (BP(ND)) based on the V(T) with noninvasively determined BP(ND) revealed an average negative bias of 0.7% in the caudate-putamen and an average positive bias of 3.1% in the low-binding regions. Scan duration of 50 minutes is required. The cerebellum is a suitable reference region for the quantification of mGluR(5) availability as measured with [(11)C]ABP688 PET in rats. Blood-based and reference region-based PET quantification shows a significant linear relationship to autoradiographic determinations.
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Affiliation(s)
- David Elmenhorst
- Institute of Neurosciences and Medicine, INM-2, Research Center Juelich, Juelich, Germany
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