1
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Endo H, Ono M, Takado Y, Matsuoka K, Takahashi M, Tagai K, Kataoka Y, Hirata K, Takahata K, Seki C, Kokubo N, Fujinaga M, Mori W, Nagai Y, Mimura K, Kumata K, Kikuchi T, Shimozawa A, Mishra SK, Yamaguchi Y, Shimizu H, Kakita A, Takuwa H, Shinotoh H, Shimada H, Kimura Y, Ichise M, Suhara T, Minamimoto T, Sahara N, Kawamura K, Zhang MR, Hasegawa M, Higuchi M. Imaging α-synuclein pathologies in animal models and patients with Parkinson's and related diseases. Neuron 2024; 112:2540-2557.e8. [PMID: 38843838 DOI: 10.1016/j.neuron.2024.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 01/24/2024] [Accepted: 05/07/2024] [Indexed: 08/10/2024]
Abstract
Deposition of α-synuclein fibrils is implicated in Parkinson's disease (PD) and dementia with Lewy bodies (DLB), while in vivo detection of α-synuclein pathologies in these illnesses has been challenging. Here, we have developed a small-molecule ligand, C05-05, for visualizing α-synuclein deposits in the brains of living subjects. In vivo optical and positron emission tomography (PET) imaging of mouse and marmoset models demonstrated that C05-05 captured a dynamic propagation of fibrillogenesis along neural pathways, followed by disruptions of these structures. High-affinity binding of 18F-C05-05 to α-synuclein aggregates in human brain tissues was also proven by in vitro assays. Notably, PET-detectable 18F-C05-05 signals were intensified in the midbrains of PD and DLB patients as compared with healthy controls, providing the first demonstration of visualizing α-synuclein pathologies in these illnesses. Collectively, we propose a new imaging technology offering neuropathology-based translational assessments of PD and allied disorders toward diagnostic and therapeutic research and development.
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Affiliation(s)
- Hironobu Endo
- Advanced Neuroimaging Center, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba 263-8555, Japan.
| | - Maiko Ono
- Institute for Quantum Life Science, National Institutes for Quantum Science and Technology, Chiba 263-8555, Japan
| | - Yuhei Takado
- Institute for Quantum Life Science, National Institutes for Quantum Science and Technology, Chiba 263-8555, Japan
| | - Kiwamu Matsuoka
- Advanced Neuroimaging Center, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba 263-8555, Japan; Department of Psychiatry, Nara Medical University, Nara 634-8522, Japan
| | - Manami Takahashi
- Quantum Neuromapping and Neuromodulation Team, Institute for Quantum Life Science, National Institutes for Quantum Science and Technology, Chiba 263-8555, Japan
| | - Kenji Tagai
- Advanced Neuroimaging Center, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba 263-8555, Japan; Department of Psychiatry, The Jikei University School of Medicine, Tokyo 105-8461, Japan
| | - Yuko Kataoka
- Advanced Neuroimaging Center, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba 263-8555, Japan
| | - Kosei Hirata
- Advanced Neuroimaging Center, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba 263-8555, Japan; Department of Neurology and Neurological Science, Tokyo Medical and Dental University, Tokyo 113-8510, Japan
| | - Keisuke Takahata
- Advanced Neuroimaging Center, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba 263-8555, Japan; Department of Psychiatry, Keio University School of Medicine, Tokyo 160-0016, Japan
| | - Chie Seki
- Advanced Neuroimaging Center, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba 263-8555, Japan
| | - Naomi Kokubo
- Advanced Neuroimaging Center, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba 263-8555, Japan
| | - Masayuki Fujinaga
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba 263-8555, Japan
| | - Wakana Mori
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba 263-8555, Japan
| | - Yuji Nagai
- Advanced Neuroimaging Center, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba 263-8555, Japan
| | - Koki Mimura
- Advanced Neuroimaging Center, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba 263-8555, Japan; Research Center for Medical and Health Data Science, The Institute of Statistical Mathematics, Tokyo 190-8562, Japan
| | - Katsushi Kumata
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba 263-8555, Japan
| | - Tatsuya Kikuchi
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba 263-8555, Japan
| | - Aki Shimozawa
- Department of Dementia and Higher Brain Function, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Sushil K Mishra
- Department of BioMolecular Sciences, The University of Mississippi, Oxford, MS 38677, USA
| | - Yoshiki Yamaguchi
- Division of Structural Glycobiology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, Sendai 981-8558, Miyagi Japan
| | - Hiroshi Shimizu
- Department of Pathology, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Akiyoshi Kakita
- Department of Pathology, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Hiroyuki Takuwa
- Advanced Neuroimaging Center, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba 263-8555, Japan; Quantum Neuromapping and Neuromodulation Team, Institute for Quantum Life Science, National Institutes for Quantum Science and Technology, Chiba 263-8555, Japan
| | - Hitoshi Shinotoh
- Advanced Neuroimaging Center, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba 263-8555, Japan; Neurology Clinic, Chiba 260-0045, Chiba Japan
| | - Hitoshi Shimada
- Advanced Neuroimaging Center, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba 263-8555, Japan; Department of Functional Neurology & Neurosurgery, Center for Integrated Human Brain Science, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Yasuyuki Kimura
- Advanced Neuroimaging Center, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba 263-8555, Japan; Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu 474-8511, Aichi, Japan
| | - Masanori Ichise
- Advanced Neuroimaging Center, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba 263-8555, Japan
| | - Tetsuya Suhara
- National Institutes for Quantum Science and Technology, Chiba 263-8555, Japan
| | - Takafumi Minamimoto
- Advanced Neuroimaging Center, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba 263-8555, Japan
| | - Naruhiko Sahara
- Advanced Neuroimaging Center, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba 263-8555, Japan
| | - Kazunori Kawamura
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba 263-8555, Japan
| | - Ming-Rong Zhang
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba 263-8555, Japan
| | - Masato Hasegawa
- Department of Dementia and Higher Brain Function, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Makoto Higuchi
- Advanced Neuroimaging Center, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba 263-8555, Japan; Department of Neuroetiology and Diagnostic Science, Osaka Metropolitan University Graduate School of Medicine, Osaka 545-8585, Japan
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2
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Xie L, Hanyu M, Fujinaga M, Zhang Y, Hu K, Minegishi K, Jiang C, Kurosawa F, Morokoshi Y, Li HK, Hasegawa S, Nagatsu K, Zhang MR. 131I-IITM and 211At-AITM: Two Novel Small-Molecule Radiopharmaceuticals Targeting Oncoprotein Metabotropic Glutamate Receptor 1. J Nucl Med 2019; 61:242-248. [PMID: 31451486 DOI: 10.2967/jnumed.119.230946] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 07/31/2019] [Indexed: 11/16/2022] Open
Abstract
Targeted radionuclide therapy (TRT) targeting oncoproteins facilitates the delivery of therapeutic radionuclides to tumor tissues with high precision. Herein, we developed 2 new radiopharmaceuticals, 4-131I-iodo- and 4-211At-astato-N-[4-(6-(isopropylamino)pyridine-4-yl)-1,3-thiazol-2-yl]-N-methylbenzamide (131I-IITM and 211At-AITM), targeting the ectopic metabotropic glutamate receptor 1 (mGluR1) in melanomas for TRT studies. Methods: 131I-IITM and 211At-AITM were synthesized by reacting a stannyl precursor with 131I-NaI and 211At in the presence of an oxidizing agent. The therapeutic efficacy and safety of the 2 radiopharmaceuticals were investigated using mGluR1-expressing B16F10 melanoma cells and melanoma-bearing mice. Results: 131I-IITM and 211At-AITM were obtained with a radiochemical purity of greater than 99% and radiochemical yields of 42.7% ± 10.4% and 45.7% ± 6.5%, respectively, based on the total radioactivity of used radionuclides. 131I-IITM and 211At-AITM exhibited a maximum uptake of 4.66% ± 0.70 and 7.68% ± 0.71 percentage injected dose per gram (%ID/g) in the targeted melanomas, respectively, and were rapidly cleared from nontarget organs after intravenous injection. Both agents markedly inhibited melanoma growth compared with the controls (61.00% and 95.68%, respectively). In the melanoma model, considerably greater therapeutic efficacy with negligible toxicity was observed using 211At-AITM. Conclusion: The nontoxic radiopharmaceuticals 131I-IITM and 211At-AITM are useful high-precision TRT agents that can be used to target the oncoprotein mGluR1 for melanoma therapy.
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Affiliation(s)
- Lin Xie
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Masayuki Hanyu
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Masayuki Fujinaga
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Yiding Zhang
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Kuan Hu
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Katsuyuki Minegishi
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Cuiping Jiang
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Fuki Kurosawa
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan.,Department of Charged Particle Therapy Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan; and
| | - Yukie Morokoshi
- Department of Charged Particle Therapy Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan; and
| | - Huizi Keiko Li
- Department of Charged Particle Therapy Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan; and.,The Japan Society for the Promotion of Science, Tokyo, Japan
| | - Sumitaka Hasegawa
- Department of Charged Particle Therapy Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan; and
| | - Kotaro Nagatsu
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Ming-Rong Zhang
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
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3
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Xu Y, Li Z. Imaging metabotropic glutamate receptor system: Application of positron emission tomography technology in drug development. Med Res Rev 2019; 39:1892-1922. [DOI: 10.1002/med.21566] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Revised: 01/18/2019] [Accepted: 01/24/2019] [Indexed: 12/17/2022]
Affiliation(s)
- Youwen Xu
- Independent Consultant and Contractor, Radiopharmaceutical Development, Validation and Bio-Application; Philadelphia Pennsylvania
| | - Zizhong Li
- Pharmaceutical Research and Development, SOFIE Biosciences; Somerset New Jersey
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4
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Krüll J, Heinrich MR. [
18
F]Fluorine‐Labeled Pharmaceuticals: Direct Aromatic Fluorination Compared to Multi‐Step Strategies. ASIAN J ORG CHEM 2018. [DOI: 10.1002/ajoc.201800494] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Jasmin Krüll
- Department of Chemistry and Pharmacy, Pharmaceutical ChemistryFriedrich-Alexander Universität Erlangen-Nürnberg Nikolaus-Fiebiger-Str. 10 91058 Erlangen
| | - Markus R. Heinrich
- Department of Chemistry and Pharmacy, Pharmaceutical ChemistryFriedrich-Alexander Universität Erlangen-Nürnberg Nikolaus-Fiebiger-Str. 10 91058 Erlangen
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5
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Taylor NJ, Emer E, Preshlock S, Schedler M, Tredwell M, Verhoog S, Mercier J, Genicot C, Gouverneur V. Derisking the Cu-Mediated 18F-Fluorination of Heterocyclic Positron Emission Tomography Radioligands. J Am Chem Soc 2017; 139:8267-8276. [PMID: 28548849 DOI: 10.1021/jacs.7b03131] [Citation(s) in RCA: 138] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Molecules labeled with fluorine-18 (18F) are used in positron emission tomography to visualize, characterize and measure biological processes in the body. Despite recent advances in the incorporation of 18F onto arenes, the development of general and efficient approaches to label radioligands necessary for drug discovery programs remains a significant task. This full account describes a derisking approach toward the radiosynthesis of heterocyclic positron emission tomography (PET) radioligands using the copper-mediated 18F-fluorination of aryl boron reagents with 18F-fluoride as a model reaction. This approach is based on a study examining how the presence of heterocycles commonly used in drug development affects the efficiency of 18F-fluorination for a representative aryl boron reagent, and on the labeling of more than 50 (hetero)aryl boronic esters. This set of data allows for the application of this derisking strategy to the successful radiosynthesis of seven structurally complex pharmaceutically relevant heterocycle-containing molecules.
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Affiliation(s)
- Nicholas J Taylor
- University of Oxford , Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Enrico Emer
- University of Oxford , Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Sean Preshlock
- University of Oxford , Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Michael Schedler
- University of Oxford , Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Matthew Tredwell
- University of Oxford , Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Stefan Verhoog
- University of Oxford , Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Joel Mercier
- UCB Biopharma SPRL , 1420 Braine-L'Alleud, Belgium
| | | | - Véronique Gouverneur
- University of Oxford , Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, U.K
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6
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Successful Strategies to Determine High-Resolution Structures of GPCRs. Trends Pharmacol Sci 2016; 37:1055-1069. [DOI: 10.1016/j.tips.2016.09.009] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 09/02/2016] [Accepted: 09/15/2016] [Indexed: 12/26/2022]
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7
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Yamasaki T, Fujinaga M, Yui J, Wakizaka H, Ohya T, Nengaki N, Ogawa M, Ikoma Y, Hatori A, Xie L, Kawamura K, Zhang MR. Improved Visualization and Specific Binding for Metabotropic Glutamate Receptor Subtype 1 (mGluR1) Using [11C]ITMM with Ultra-High Specific Activity in Small-Animal PET. PLoS One 2015; 10:e0130006. [PMID: 26076143 PMCID: PMC4468202 DOI: 10.1371/journal.pone.0130006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Accepted: 04/29/2015] [Indexed: 12/15/2022] Open
Abstract
Metabotropic glutamate receptor subtype 1 (mGluR1) is a crucial target in the development of new medications to treat central nervous system (CNS) disorders. Recently, we developed N-[4-[6-(isopropylamino)pyrimidin-4-yl]-1,3-thiazol-2-yl]-4-[11C]methoxy-N-methyl-benzamide ([11C]ITMM) as a useful positron emission tomography (PET) probe for mGluR1 in clinical studies. Here, we aimed to improve visualization and threshold of specific binding for mGluR1 using [11C]ITMM with ultra-high specific activity (SA) of > 3,500 GBq/μmol in rat brains. A two-tissue compartment model indicated large differences between the two SAs in the constants k3 and k4, representing binding ability for mGluR1, while constants K1 and k2 showed no differences. The total distribution volume (VT) values of conventional and ultra-high SA were 9.1 and 11.2 in the thalamus, 7.7 and 9.7 in the striatum, and 6.4 and 8.5 mL/cm3 in the substantia nigra, respectively. The specific binding of [11C]ITMM with ultra-high SA was significantly higher than the conventional SA, especially in the basal ganglia. Parametric PET images scaled with VT of the ultra-high SA clearly identified regional differences in the rat brain. In conclusion, PET studies using [11C]ITMM with ultra-high SA could sufficiently improve visualization and specific binding for mGluR1, which could help further understanding for mGluR1 functions in CNS disorders.
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Affiliation(s)
- Tomoteru Yamasaki
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
- * E-mail:
| | - Masayuki Fujinaga
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Joji Yui
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Hidekatsu Wakizaka
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Tomoyuki Ohya
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Nobuki Nengaki
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Masanao Ogawa
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Yoko Ikoma
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Akiko Hatori
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Lin Xie
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Kazunori Kawamura
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Ming-Rong Zhang
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
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8
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Development of PET and SPECT probes for glutamate receptors. ScientificWorldJournal 2015; 2015:716514. [PMID: 25874256 PMCID: PMC4385697 DOI: 10.1155/2015/716514] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2014] [Accepted: 08/29/2014] [Indexed: 01/16/2023] Open
Abstract
l-Glutamate and its receptors (GluRs) play a key role in excitatory neurotransmission within the mammalian central nervous system (CNS). Impaired regulation of GluRs has also been implicated in various neurological disorders. GluRs are classified into two major groups: ionotropic GluRs (iGluRs), which are ligand-gated ion channels, and metabotropic GluRs (mGluRs), which are coupled to heterotrimeric guanosine nucleotide binding proteins (G-proteins). Positron emission tomography (PET) and single photon emission computed tomography (SPECT) imaging of GluRs could provide a novel view of CNS function and of a range of brain disorders, potentially leading to the development of new drug therapies. Although no satisfactory imaging agents have yet been developed for iGluRs, several PET ligands for mGluRs have been successfully employed in clinical studies. This paper reviews current progress towards the development of PET and SPECT probes for GluRs.
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9
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Fujinaga M, Xie L, Yamasaki T, Yui J, Shimoda Y, Hatori A, Kumata K, Zhang Y, Nengaki N, Kawamura K, Zhang MR. Synthesis and Evaluation of 4-Halogeno-N-[4-[6-(isopropylamino)pyrimidin-4-yl]-1,3-thiazol-2-yl]-N-[11C]methylbenzamide for Imaging of Metabotropic Glutamate 1 Receptor in Melanoma. J Med Chem 2015; 58:1513-23. [DOI: 10.1021/jm501845n] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Masayuki Fujinaga
- Molecular
Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Lin Xie
- Molecular
Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Tomoteru Yamasaki
- Molecular
Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Joji Yui
- Molecular
Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Yoko Shimoda
- Molecular
Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Akiko Hatori
- Molecular
Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Katsushi Kumata
- Molecular
Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Yiding Zhang
- Molecular
Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Nobuki Nengaki
- Molecular
Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
- SHI Accelerator
Service Co. Ltd., 5-9-11 Kitashinagawa, Shinagawa-ku, Tokyo 141-8686, Japan
| | - Kazunori Kawamura
- Molecular
Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Ming-Rong Zhang
- Molecular
Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
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10
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Cho HP, Engers DW, Venable DF, Niswender CM, Lindsley CW, Conn PJ, Emmitte KA, Rodriguez AL. A novel class of succinimide-derived negative allosteric modulators of metabotropic glutamate receptor subtype 1 provides insight into a disconnect in activity between the rat and human receptors. ACS Chem Neurosci 2014; 5:597-610. [PMID: 24798819 DOI: 10.1021/cn5000343] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Recent progress in the discovery of mGlu₁ allosteric modulators has suggested the modulation of mGlu₁ could offer possible treatment for a number of central nervous system disorders; however, the available chemotypes are inadequate to fully investigate the therapeutic potential of mGlu₁ modulation. To address this issue, we used a fluorescence-based high-throughput screening assay to screen an allosteric modulator-biased library of compounds to generate structurally diverse mGlu₁ negative allosteric modulator hits for chemical optimization. Herein, we describe the discovery and characterization of a novel mGlu₁ chemotype. This series of succinimide negative allosteric modulators, exemplified by VU0410425, exhibited potent inhibitory activity at rat mGlu₁ but was, surprisingly, inactive at human mGlu₁. VU0410425 and a set of chemically diverse mGlu₁ negative allosteric modulators previously reported in the literature were utilized to examine this species disconnect between rat and human mGlu₁ activity. Mutation of the key transmembrane domain residue 757 and functional screening of VU0410425 and the literature compounds suggests that amino acid 757 plays a role in the activity of these compounds, but the contribution of the residue is scaffold specific, ranging from critical to minor. The operational model of allosterism was used to estimate the binding affinities of each compound to compare to functional data. This novel series of mGlu₁ negative allosteric modulators provides valuable insight into the pharmacology underlying the disconnect between rat and human mGlu₁ activity, an issue that must be understood to progress the therapeutic potential of allosteric modulators of mGlu₁.
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Affiliation(s)
| | | | | | | | - Craig W. Lindsley
- Department
of Chemistry, Vanderbilt University, Nashville, Tennessee 37232, United States
| | | | - Kyle A. Emmitte
- Department
of Chemistry, Vanderbilt University, Nashville, Tennessee 37232, United States
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11
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Xie L, Yui J, Fujinaga M, Hatori A, Yamasaki T, Kumata K, Wakizaka H, Furutsuka K, Takei M, Jin ZH, Furukawa T, Kawamura K, Zhang MR. Molecular imaging of ectopic metabotropic glutamate 1 receptor in melanoma with a positron emission tomography radioprobe (18) F-FITM. Int J Cancer 2014; 135:1852-9. [PMID: 24643962 DOI: 10.1002/ijc.28842] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 02/25/2014] [Indexed: 11/09/2022]
Abstract
Oncoimaging using positron emission tomography (PET) with a specific radioprobe would facilitate individualized cancer management. Evidence indicates that ectopically expressed metabotropic glutamate 1 (mGlu1) receptor independently induces melanocyte carcinogenesis, and it is therefore becoming an important target for personalized diagnosis and treatment strategies for melanomas. Here, we report the development of an oncoprotein-based PET imaging platform in melanomas for noninvasive visualization and quantification of mGlu1 with a novel mGlu1-specific radioprobe, 4-(18)F-fluoro-N-[4-[6-(isopropyl amino)pyrimidin-4-yl]-1,3-thiazol-2-yl]-N-methylbenzamide ((18)F-FITM). (18)F-FITM shows excellent pharmacokinetics, namely the dense and specific accumulation in mGlu1-positive melanomas versus mGlu1-negative hepatoma and normal tissues. Furthermore, the accumulation levels of radioactivity corresponded to the extent of tumor and to levels of mGlu1 protein expression in melanomas and melanoma metastasis. The (18)F-FITM PET imaging platform, as a noninvasive personalized diagnostic tool, is expected to open a new avenue for defining individualized therapeutic strategies, clinical trials, patient management and understanding mGlu1-triggered oncologic events in melanomas.
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Affiliation(s)
- Lin Xie
- Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
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Wu H, Wang C, Gregory KJ, Han GW, Cho HP, Xia Y, Niswender CM, Katritch V, Meiler J, Cherezov V, Conn PJ, Stevens RC. Structure of a class C GPCR metabotropic glutamate receptor 1 bound to an allosteric modulator. Science 2014; 344:58-64. [PMID: 24603153 DOI: 10.1126/science.1249489] [Citation(s) in RCA: 397] [Impact Index Per Article: 39.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The excitatory neurotransmitter glutamate induces modulatory actions via the metabotropic glutamate receptors (mGlus), which are class C G protein-coupled receptors (GPCRs). We determined the structure of the human mGlu1 receptor seven-transmembrane (7TM) domain bound to a negative allosteric modulator, FITM, at a resolution of 2.8 angstroms. The modulator binding site partially overlaps with the orthosteric binding sites of class A GPCRs but is more restricted than most other GPCRs. We observed a parallel 7TM dimer mediated by cholesterols, which suggests that signaling initiated by glutamate's interaction with the extracellular domain might be mediated via 7TM interactions within the full-length receptor dimer. A combination of crystallography, structure-activity relationships, mutagenesis, and full-length dimer modeling provides insights about the allosteric modulation and activation mechanism of class C GPCRs.
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Affiliation(s)
- Huixian Wu
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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13
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Xu R, Zanotti-Fregonara P, Zoghbi SS, Gladding RL, Woock AE, Innis RB, Pike VW. Synthesis and evaluation in monkey of [(18)F]4-fluoro-N-methyl-N-(4-(6-(methylamino)pyrimidin-4-yl)thiazol-2-yl)benzamide ([(18)F]FIMX): a promising radioligand for PET imaging of brain metabotropic glutamate receptor 1 (mGluR1). J Med Chem 2013; 56:9146-55. [PMID: 24147864 DOI: 10.1021/jm4012017] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
We sought to develop a PET radioligand that would be useful for imaging human brain metabotropic subtype 1 receptors (mGluR1) in neuropsychiatric disorders and in drug development. 4-Fluoro-N-methyl-N-(4-(6-(methylamino)pyrimidin-4-yl)thiazol-2-yl)benzamide (FIMX, 11) was identified as having favorable properties for development as a PET radioligand. We developed a method for preparing [(18)F]11 in useful radiochemical yield and in high specific activity from [(18)F]fluoride ion and an N-Boc-protected (phenyl)aryliodonium salt precursor (15). In baseline experiments in rhesus monkey, [(18)F]11 gave high brain radioactivity uptake, reflecting the expected distribution of mGluR1 with notably high uptake in cerebellum, which became 47% lower by 120 min after radioligand injection. Pharmacological challenges demonstrated that a very high proportion of the radioactivity in monkey brain was bound specifically and reversibly to mGluR1. [(18)F]11 is concluded to be an effective PET radioligand for imaging mGluR1 in monkey brain and therefore merits further evaluation in human subjects.
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Affiliation(s)
- Rong Xu
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health , Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892, United States
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Toyohara J, Sakata M, Oda K, Ishii K, Ito K, Hiura M, Fujinaga M, Yamasaki T, Zhang MR, Ishiwata K. Initial Human PET Studies of Metabotropic Glutamate Receptor Type 1 Ligand 11C-ITMM. J Nucl Med 2013; 54:1302-7. [DOI: 10.2967/jnumed.113.119891] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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Zanotti-Fregonara P, Barth VN, Zoghbi SS, Liow JS, Nisenbaum E, Siuda E, Gladding RL, Rallis-Frutos D, Morse C, Tauscher J, Pike VW, Innis RB. 11C-LY2428703, a positron emission tomographic radioligand for the metabotropic glutamate receptor 1, is unsuitable for imaging in monkey and human brains. EJNMMI Res 2013; 3:47. [PMID: 23758896 PMCID: PMC3683333 DOI: 10.1186/2191-219x-3-47] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Accepted: 05/31/2013] [Indexed: 02/03/2023] Open
Abstract
Background A recent study from our laboratory demonstrated that 11C-LY2428703, a new positron emission tomographic radioligand for metabotropic glutamate receptor 1 (mGluR1), has promising in vitro properties and excellent in vivo performance for imaging rat brain. The present study evaluated 11C-LY2428703 for imaging mGluR1 in monkey and human brains. Methods Rhesus monkeys were imaged at baseline and after administration of an mGluR1 blocking agent to calculate nonspecific binding, as well as after the administration of permeability glycoprotein (P-gp) and breast cancer resistance protein (BCRP) blockers to assess whether 11C-LY2428703 is a substrate for efflux transporters at the blood–brain barrier. Human imaging was performed at baseline in three healthy volunteers, and arterial input function was measured. Results Overall brain uptake was low in monkeys, though slightly higher in the cerebellum, where mGluR1s are concentrated. However, the uptake was not clearly displaceable in the scans after mGluR1 blockade. Brain penetration of the ligand did not increase after P-gp and BCRP blockade. Brain uptake was similarly low in all human subjects (mean VT with a two-tissue compartment model, 0.093 ± 0.012 mL/cm3) and for all regions, including the cerebellum. Conclusions Despite promising in vitro and in vivo results in rodents, 11C-LY2428703 was unsuitable for imaging mGluR1s in monkey or human brain because of low brain uptake, which was likely caused by high binding to plasma proteins.
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Affiliation(s)
- Paolo Zanotti-Fregonara
- Molecular Imaging Branch, National Institute of Mental Health, 10 Center Drive, Bethesda, MD 20892, USA.
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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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17
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Toyohara J, Sakata M, Fujinaga M, Yamasaki T, Oda K, Ishii K, Zhang MR, Moriguchi Jeckel CM, Ishiwata K. Preclinical and the first clinical studies on [11C]ITMM for mapping metabotropic glutamate receptor subtype 1 by positron emission tomography. Nucl Med Biol 2013; 40:214-20. [DOI: 10.1016/j.nucmedbio.2012.11.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Revised: 11/19/2012] [Accepted: 11/19/2012] [Indexed: 01/29/2023]
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18
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Fujinaga M, Yamasaki T, Maeda J, Yui J, Xie L, Nagai Y, Nengaki N, Hatori A, Kumata K, Kawamura K, Zhang MR. Development of N-[4-[6-(Isopropylamino)pyrimidin-4-yl]-1,3-thiazol-2-yl]-N-methyl-4-[11C]methylbenzamide for Positron Emission Tomography Imaging of Metabotropic Glutamate 1 Receptor in Monkey Brain. J Med Chem 2012. [DOI: 10.1021/jm301597s] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Masayuki Fujinaga
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1
Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Tomoteru Yamasaki
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1
Anagawa, Inage-ku, Chiba 263-8555, Japan
- Graduate School of Pharmaceutical
Sciences, Tohoku University, Aoba-ku, Sendai
980-8574, Japan
| | - Jun Maeda
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1
Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Joji Yui
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1
Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Lin Xie
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1
Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Yuji Nagai
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1
Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Nobuki Nengaki
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1
Anagawa, Inage-ku, Chiba 263-8555, Japan
- SHI Accelerator Service Co. Ltd., 5-9-11 Kitashinagawa, Shinagawa-ku, Tokyo
141-8686, Japan
| | - Akiko Hatori
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1
Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Katsushi Kumata
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1
Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Kazunori Kawamura
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1
Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Ming-Rong Zhang
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1
Anagawa, Inage-ku, Chiba 263-8555, Japan
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Zanotti-Fregonara P, Barth VN, Liow JS, Zoghbi SS, Clark DT, Rhoads E, Siuda E, Heinz BA, Nisenbaum E, Dressman B, Joshi E, Luffer-Atlas D, Fisher MJ, Masters JJ, Goebl N, Kuklish SL, Morse C, Tauscher J, Pike VW, Innis RB. Evaluation in vitro and in animals of a new 11C-labeled PET radioligand for metabotropic glutamate receptors 1 in brain. Eur J Nucl Med Mol Imaging 2012; 40:245-53. [PMID: 23135321 DOI: 10.1007/s00259-012-2269-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 10/01/2012] [Indexed: 10/27/2022]
Abstract
PURPOSE Two allosteric modulators of the group I metabotropic glutamate receptors (mGluR1 and mGluR5) were evaluated as positron emission tomography (PET) radioligands for mGluR1. METHODS LY2428703, a full mGluR1 antagonist (IC(50) 8.9 nM) and partial mGluR5 antagonist (IC(50) 118 nM), and LSN2606428, a full mGluR1 and mGluR5 antagonist (IC(50) 35.3 nM and 10.2 nM, respectively) were successfully labeled with (11)C and evaluated as radioligands for mGluR1. The pharmacology of LY2428703 was comprehensively assessed in vitro and in vivo, and its biodistribution was investigated by liquid chromatography-mass spectrometry/mass spectrometry, and by PET imaging in the rat. In contrast, LSN2606428 was only evaluated in vitro; further evaluation was stopped due to its unfavorable pharmacological properties and binding affinity. RESULTS (11)C-LY2428703 showed promising characteristics, including: (1) high potency for binding to human mGluR1 (IC(50) 8.9 nM) with no significant affinity for other human mGlu receptors (mGluR2 through mGluR8); (2) binding to brain displaceable by administration of an mGluR1 antagonist; (3) only one major radiometabolite in both plasma and brain, with a negligible brain concentration (with 3.5 % of the total radioactivity in cerebellum) and no receptor affinity; (4) a large specific and displaceable signal in the mGluR1-rich cerebellum with no significant in vivo affinity for mGluR5, as shown by PET studies in rats; and (5) lack of substrate behavior for efflux transporters at the blood-brain barrier, as shown by PET studies conducted in wild-type and knockout mice. CONCLUSION (11)C-LY2428703, a new PET radioligand for mGluR1 quantification, displayed promising characteristics both in vitro and in vivo in rodents.
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Affiliation(s)
- Paolo Zanotti-Fregonara
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, 10 Center Drive, Bethesda, MD 20892, USA
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Majo VJ, Prabhakaran J, Mann JJ, Kumar JSD. PET and SPECT tracers for glutamate receptors. Drug Discov Today 2012; 18:173-84. [PMID: 23092894 DOI: 10.1016/j.drudis.2012.10.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Revised: 07/10/2012] [Accepted: 10/15/2012] [Indexed: 12/19/2022]
Abstract
Radioligands for PET imaging of glutamate receptors will have the potential for studying neurological and neuropsychiatric disorders and their diagnosis and therapeutic intervention. Glutamate is the major excitatory neurotransmitter in the brain and is implicated in the pathophysiology of many neurodegenerative and neuropsychiatric disorders. Glutamate and its receptors are potential targets in the treatment of these disorders. Glutamate signaling is mediated through ionotropic and metabotropic receptors. The abundant concentration of these receptors can facilitate their in vivo quantification using positron emission tomography (PET). Glutamate receptors are a potentially important set of targets for monitoring disease progression, for evaluating the effect of therapy and for new treatment development based on the quantification of receptor occupancy. Here, we review the PET and single-photon emission computed tomography (SPECT) radioligands that have been developed for imaging glutamate receptors in living brain.
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Affiliation(s)
- Vattoly J Majo
- Division of Molecular Imaging and Neuropathology, Department of Psychiatry, Columbia University, New York, NY 10032, USA
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Huang Y, Narendran R, Bischoff F, Guo N, Bae SA, Hwang DR, Lesage AS, Laruelle M. Synthesis and characterization of two PET radioligands for the metabotropic glutamate 1 (mGlu1) receptor. Synapse 2012; 66:1002-14. [PMID: 22927303 DOI: 10.1002/syn.21606] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Accepted: 08/20/2012] [Indexed: 11/09/2022]
Abstract
The metabotropic glutamate 1 receptor (mGlu1) is an important protein in the regulation of glutamate transmission in the brain, and believed to be involved in disorders such as ischemia, epilepsy, neuropathic pain, anxiety, and schizophrenia. The goal of this study was to evaluate two selective mGlu1 antagonists [(11) C]3 and [(18) F]4 as potential PET radioligands for the in vivo imaging of the mGlu1 receptor. Biodistribution studies in rats indicated high uptake of [(11) C]3 and [(18) F]4 in the brain. The highest activity level was found in the cerebellum, followed by striatum, hippocampus, frontal cortex, and medulla, in a pattern consistent with the distribution of mGlu1 receptor in rat. At 30 min postinjection, the activity ratio of cerebellum to medulla was 4.5 for [(11) C]3, indicating a high degree of specific binding, while specific binding was lower for [(18) F]4 (cerebellum to medulla activity ratio of 2.0). Moreover, binding of the radioligands [(11) C]3 and [(18) F]4 in mGlu1 receptor-rich region such as cerebellum was blocked by pretreatment of the rats with their respective unlabeled compound or the selective mGlu1 antagonist (compound 5, 2 mg/kg each), but not by the selective mGlu2 antagonist LY341495, or the selective mGlu5 antagonist MPEP (2 mg/kg), thus indicating the binding specificity and selectivity of [(11) C]3 and [(18) F]4 to the mGlu1 receptor. However, in imaging experiments in baboons [(11) C]3 displayed a small specific binding signal only in the cerebellum, while the specific binding of [(18) F]4 was difficult to detect. Species differences in receptor density and affinity of the radioligands in large part account for the differences in the behavior of [(11) C]3 and [(18) F]4 in rats and baboons. Radioligands with higher affinity and/or lower lipophilicity are needed to successfully image the mGlu1 receptor in humans.
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Affiliation(s)
- Yiyun Huang
- Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, New York, USA.
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Yamasaki T, Fujinaga M, Kawamura K, Yui J, Hatori A, Ohya T, Xie L, Wakizaka H, Yoshida Y, Fukumura T, Zhang MR. In Vivo Measurement of the Affinity and Density of Metabotropic Glutamate Receptor Subtype 1 in Rat Brain Using 18F-FITM in Small-Animal PET. J Nucl Med 2012; 53:1601-7. [DOI: 10.2967/jnumed.112.105908] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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23
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Fujinaga M, Yamasaki T, Yui J, Hatori A, Xie L, Kawamura K, Asagawa C, Kumata K, Yoshida Y, Ogawa M, Nengaki N, Fukumura T, Zhang MR. Synthesis and evaluation of novel radioligands for positron emission tomography imaging of metabotropic glutamate receptor subtype 1 (mGluR1) in rodent brain. J Med Chem 2012; 55:2342-52. [PMID: 22316010 DOI: 10.1021/jm201590g] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We designed three novel positron emission tomography ligands, N-(4-(6-(isopropylamino)pyrimidin-4-yl)-1,3-thiazol-2-yl)-4-[(11)C]methoxy-N-methylbenzamide ([(11)C]6), 4-[(18)F]fluoroethoxy-N-[4-[6-(isopropylamino)pyrimidin-4-yl]-1,3-thiazol-2-yl]-N-methylbenzamide ([(18)F]7), and 4-[(18)F]fluoropropoxy-N-[4-[6-(isopropylamino)pyrimidin-4-yl]-1,3-thiazol-2-yl]-N-methylbenzamide ([(18)F]8), for imaging metabotropic glutamate receptor type 1 (mGluR1) in rodent brain. Unlabeled compound 6 was synthesized by benzoylation of 4-pyrimidinyl-2-methylaminothiazole 10, followed by reaction with isopropylamine. Removal of the methyl group in 6 gave phenol precursor 12 for radiosynthesis. Two fluoroalkoxy analogues 7 and 8 were prepared by reacting 12 with tosylates 13 and 14. Radioligands [(11)C]6, [(18)F]7, and [(18)F]8 were synthesized by O-[(11)C]methylation or [(18)F]fluoroalkylation of 12. Compound 6 showed high in vitro binding affinity for mGluR1, whereas 7 and 8 had weak affinity. Autoradiography using rat brain sections showed that [(11)C]6 binding is aligned with the reported distribution of mGluR1 with high specific binding in the cerebellum and thalamus. PET study with [(11)C]6 in rats showed high brain uptake and a similar distribution pattern to that in autoradiography, indicating the usefulness of [(11)C]6 for imaging brain mGluR1.
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Affiliation(s)
- Masayuki Fujinaga
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
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Imaging for metabotropic glutamate receptor subtype 1 in rat and monkey brains using PET with [18F]FITM. Eur J Nucl Med Mol Imaging 2011; 39:632-41. [DOI: 10.1007/s00259-011-1995-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Accepted: 11/03/2011] [Indexed: 11/26/2022]
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