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Chauveau F, Winkeler A, Chalon S, Boutin H, Becker G. PET imaging of neuroinflammation: any credible alternatives to TSPO yet? Mol Psychiatry 2024:10.1038/s41380-024-02656-9. [PMID: 38997465 DOI: 10.1038/s41380-024-02656-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 06/26/2024] [Accepted: 07/01/2024] [Indexed: 07/14/2024]
Abstract
Over the last decades, the role of neuroinflammation in neuropsychiatric conditions has attracted an exponentially growing interest. A key driver for this trend was the ability to image brain inflammation in vivo using PET radioligands targeting the Translocator Protein 18 kDa (TSPO), which is known to be expressed in activated microglia and astrocytes upon inflammatory events as well as constitutively in endothelial cells. TSPO is a mitochondrial protein that is expressed mostly by microglial cells upon activation but is also expressed by astrocytes in some conditions and constitutively by endothelial cells. Therefore, our current understanding of neuroinflammation dynamics is hampered by the lack of alternative targets available for PET imaging. We performed a systematic search and review on radiotracers developed for neuroinflammation PET imaging apart from TSPO. The following targets of interest were identified through literature screening (including previous narrative reviews): P2Y12R, P2X7R, CSF1R, COX (microglial targets), MAO-B, I2BS (astrocytic targets), CB2R & S1PRs (not specific of a single cell type). We determined the level of development and provided a scoping review for each target. Strikingly, astrocytic biomarker MAO-B has progressed in clinical investigations the furthest, while few radiotracers (notably targeting S1P1Rs, CSF1R) are being implemented in clinical investigations. Other targets such as CB2R and P2X7R have proven disappointing in clinical studies (e.g. poor signal, lack of changes in disease conditions, etc.). While astrocytic targets are promising, development of new biomarkers and tracers specific for microglial activation has proven challenging.
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Affiliation(s)
- Fabien Chauveau
- Université Claude Bernard Lyon 1, Centre de Recherche en Neurosciences de Lyon, Inserm U1028, CNRS UMR5292, BIORAN, Groupement Hospitalier Est - CERMEP, 59 boulevard Pinel, 69677, Bron, Cedex, France
| | - Alexandra Winkeler
- Université Paris-Saclay, Inserm, CNRS, CEA, BioMaps, Service Hospitalier Frédéric Joliot, 4 place du général Leclerc, 91401, Orsay, France
| | - Sylvie Chalon
- UMR 1253 iBrain, Université de Tours - INSERM, Bâtiment Planiol, UFR de Médecine, 10 Boulevard Tonnellé, 37032, Tours, Cedex 01, France
| | - Hervé Boutin
- UMR 1253 iBrain, Université de Tours - INSERM, Bâtiment Planiol, UFR de Médecine, 10 Boulevard Tonnellé, 37032, Tours, Cedex 01, France.
| | - Guillaume Becker
- Université Claude Bernard Lyon 1, Centre de Recherche en Neurosciences de Lyon, Inserm U1028, CNRS UMR5292, BIORAN, Groupement Hospitalier Est - CERMEP, 59 boulevard Pinel, 69677, Bron, Cedex, France
- Agence Nationale de Sécurité Sanitaire de l'Alimentation, de l'Environnement et du Travail, 14 rue Pierre et Marie Curie, 94701, Maisons-Alfort, Cedex, France
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2
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Teodoro R, Gündel D, Deuther-Conrad W, Kazimir A, Toussaint M, Wenzel B, Bormans G, Hey-Hawkins E, Kopka K, Brust P, Moldovan RP. Synthesis, Structure-Activity Relationships, Radiofluorination, and Biological Evaluation of [ 18F]RM365, a Novel Radioligand for Imaging the Human Cannabinoid Receptor Type 2 (CB2R) in the Brain with PET. J Med Chem 2023; 66:13991-14010. [PMID: 37816245 PMCID: PMC10614203 DOI: 10.1021/acs.jmedchem.3c01035] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Indexed: 10/12/2023]
Abstract
The development of cannabinoid receptor type 2 (CB2R) PET radioligands has been intensively explored due to the pronounced CB2R upregulation under various pathological conditions. Herein, we report on the synthesis of a series of CB2R affine fluorinated indole-2-carboxamide ligands. Compound RM365 was selected for PET radiotracer development due to its high CB2R affinity (Ki = 2.1 nM) and selectivity over CB1R (factor > 300). Preliminary in vitro evaluation of [18F]RM365 indicated species differences in the binding to CB2R (KD of 2.32 nM for the hCB2R vs KD > 10,000 nM for the rCB2R). Metabolism studies in mice revealed a high in vivo stability of [18F]RM365. PET imaging in a rat model of local hCB2R(D80N) overexpression in the brain demonstrates the ability of [18F]RM365 to reach and selectively label the hCB2R(D80N) with a high signal-to-background ratio. Thus, [18F]RM365 is a very promising PET radioligand for the imaging of upregulated hCB2R expression under pathological conditions.
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Affiliation(s)
- Rodrigo Teodoro
- Institute
of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals,
Research Site Leipzig, Helmholtz-Zentrum
Dresden-Rossendorf (HZDR), 04318 Leipzig, Germany
| | - Daniel Gündel
- Institute
of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals,
Research Site Leipzig, Helmholtz-Zentrum
Dresden-Rossendorf (HZDR), 04318 Leipzig, Germany
| | - Winnie Deuther-Conrad
- Institute
of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals,
Research Site Leipzig, Helmholtz-Zentrum
Dresden-Rossendorf (HZDR), 04318 Leipzig, Germany
| | - Aleksandr Kazimir
- Faculty
of Chemistry and Mineralogy, Institute of Inorganic Chemistry, Universität Leipzig, Johannisallee 29, 04103 Leipzig, Germany
| | - Magali Toussaint
- Institute
of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals,
Research Site Leipzig, Helmholtz-Zentrum
Dresden-Rossendorf (HZDR), 04318 Leipzig, Germany
| | - Barbara Wenzel
- Institute
of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals,
Research Site Leipzig, Helmholtz-Zentrum
Dresden-Rossendorf (HZDR), 04318 Leipzig, Germany
| | - Guy Bormans
- Radiopharmaceutical
Research, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, BE-3000 Leuven, Belgium
| | - Evamarie Hey-Hawkins
- Faculty
of Chemistry and Mineralogy, Institute of Inorganic Chemistry, Universität Leipzig, Johannisallee 29, 04103 Leipzig, Germany
| | - Klaus Kopka
- Institute
of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals,
Research Site Leipzig, Helmholtz-Zentrum
Dresden-Rossendorf (HZDR), 04318 Leipzig, Germany
- Faculty
of Chemistry and Food Chemistry, School of Science, TU Dresden, 01069 Dresden, Germany
| | - Peter Brust
- Institute
of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals,
Research Site Leipzig, Helmholtz-Zentrum
Dresden-Rossendorf (HZDR), 04318 Leipzig, Germany
- The
Lübeck Institute of Experimental Dermatology, University Medical Center Schleswig-Holstein, 23562 Lübeck, Germany
| | - Rareş-Petru Moldovan
- Institute
of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals,
Research Site Leipzig, Helmholtz-Zentrum
Dresden-Rossendorf (HZDR), 04318 Leipzig, Germany
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3
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Gündel D, Deuther-Conrad W, Ueberham L, Kaur S, Otikova E, Teodoro R, Toussaint M, Lai TH, Clauß O, Scheunemann M, Bormans G, Bachmann M, Kopka K, Brust P, Moldovan RP. Structure-Based Design, Optimization, and Development of [ 18F]LU13: A Novel Radioligand for Cannabinoid Receptor Type 2 Imaging in the Brain with PET. J Med Chem 2022; 65:9034-9049. [PMID: 35771668 DOI: 10.1021/acs.jmedchem.2c00256] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The cannabinoid receptor type 2 (CB2R) is an attractive target for the diagnosis and therapy of neurodegenerative diseases and cancer. In this study, we aimed at the development of a novel 18F-labeled radioligand starting from the structure of the known naphthyrid-2-one CB2R ligands. Compound 28 (LU13) was identified with the highest binding affinity and selectivity versus CB1R (CB2RKi = 0.6 nM; CB1RKi/CB2RKi > 1000) and was selected for radiolabeling with fluorine-18 and biological characterization. The new radioligand [18F]LU13 showed high CB2R affinity in vitro as well as high metabolic stability in vivo. PET imaging with [18F]LU13 in a rat model of vector-based/-related hCB2R overexpression in the striatum revealed a high signal-to-background ratio. Thus, [18F]LU13 is a novel and highly promising PET radioligand for the imaging of upregulated CB2R expression under pathological conditions in the brain.
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Affiliation(s)
- Daniel Gündel
- Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Research Site Leipzig, 04318 Leipzig, Germany
| | - Winnie Deuther-Conrad
- Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Research Site Leipzig, 04318 Leipzig, Germany
| | - Lea Ueberham
- Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Research Site Leipzig, 04318 Leipzig, Germany
| | - Sarandeep Kaur
- Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Research Site Leipzig, 04318 Leipzig, Germany
| | - Elina Otikova
- Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Research Site Leipzig, 04318 Leipzig, Germany
| | - Rodrigo Teodoro
- Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Research Site Leipzig, 04318 Leipzig, Germany
| | - Magali Toussaint
- Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Research Site Leipzig, 04318 Leipzig, Germany
| | - Thu Hang Lai
- Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Research Site Leipzig, 04318 Leipzig, Germany.,Department of Research and Development, ROTOP Pharmaka GmbH, 01069 Dresden, Germany
| | - Oliver Clauß
- Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Research Site Leipzig, 04318 Leipzig, Germany
| | - Matthias Scheunemann
- Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Research Site Leipzig, 04318 Leipzig, Germany
| | - Guy Bormans
- Radiopharmaceutical Research, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, BE-3000 Leuven, Belgium
| | - Michael Bachmann
- Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Research Site Leipzig, 04318 Leipzig, Germany
| | - Klaus Kopka
- Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Research Site Leipzig, 04318 Leipzig, Germany.,Faculty of Chemistry and Food Chemistry, School of Science, TU Dresden, 01069 Dresden, Germany
| | - Peter Brust
- Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Research Site Leipzig, 04318 Leipzig, Germany.,The Lübeck Institute of Experimental Dermatology, University Medical Center Schleswig-Holstein, 23562 Lübeck, Germany
| | - Rareş-Petru Moldovan
- Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Research Site Leipzig, 04318 Leipzig, Germany
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Beaino W, Janssen B, Vugts DJ, de Vries HE, Windhorst AD. Towards PET imaging of the dynamic phenotypes of microglia. Clin Exp Immunol 2021; 206:282-300. [PMID: 34331705 PMCID: PMC8561701 DOI: 10.1111/cei.13649] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 07/21/2021] [Accepted: 07/21/2021] [Indexed: 02/06/2023] Open
Abstract
There is increasing evidence showing the heterogeneity of microglia activation in neuroinflammatory and neurodegenerative diseases. It has been hypothesized that pro‐inflammatory microglia are detrimental and contribute to disease progression, while anti‐inflammatory microglia play a role in damage repair and remission. The development of therapeutics targeting the deleterious glial activity and modulating it into a regenerative phenotype relies heavily upon a clearer understanding of the microglia dynamics during disease progression and the ability to monitor therapeutic outcome in vivo. To that end, molecular imaging techniques are required to assess microglia dynamics and study their role in disease progression as well as to evaluate the outcome of therapeutic interventions. Positron emission tomography (PET) is such a molecular imaging technique, and provides unique capabilities for non‐invasive quantification of neuroinflammation and has the potential to discriminate between microglia phenotypes and define their role in the disease process. However, several obstacles limit the possibility for selective in vivo imaging of microglia phenotypes mainly related to the poor characterization of specific targets that distinguish the two ends of the microglia activation spectrum and lack of suitable tracers. PET tracers targeting translocator protein 18 kDa (TSPO) have been extensively explored, but despite the success in evaluating neuroinflammation they failed to discriminate between microglia activation statuses. In this review, we highlight the current knowledge on the microglia phenotypes in the major neuroinflammatory and neurodegenerative diseases. We also discuss the current and emerging PET imaging targets, the tracers and their potential in discriminating between the pro‐ and anti‐inflammatory microglia activation states.
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Affiliation(s)
- Wissam Beaino
- Department of Radiology and Nuclear Medicine, Tracer Center Amsterdam, Amsterdam UMC, Vrije Universiteit, Amsterdam, the Netherlands
| | - Bieneke Janssen
- Department of Radiology and Nuclear Medicine, Tracer Center Amsterdam, Amsterdam UMC, Vrije Universiteit, Amsterdam, the Netherlands
| | - Danielle J Vugts
- Department of Radiology and Nuclear Medicine, Tracer Center Amsterdam, Amsterdam UMC, Vrije Universiteit, Amsterdam, the Netherlands
| | - Helga E de Vries
- Department of Molecular Cell Biology and Immunology, MS Center Amsterdam, Amsterdam Neuroscience, Amsterdam UMC, Vrije Universiteit, Amsterdam, the Netherlands
| | - Albert D Windhorst
- Department of Radiology and Nuclear Medicine, Tracer Center Amsterdam, Amsterdam UMC, Vrije Universiteit, Amsterdam, the Netherlands
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5
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Duggan PJ, Kassiou M. Cannabis and Cannabinoids. Aust J Chem 2021. [DOI: 10.1071/chv74n6_fo] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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