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Dupont AC, Arlicot N, Vercouillie J, Serrière S, Maia S, Bonnet-Brilhault F, Santiago-Ribeiro MJ. Metabotropic Glutamate Receptor Subtype 5 Positron-Emission-Tomography Radioligands as a Tool for Central Nervous System Drug Development: Between Progress and Setbacks. Pharmaceuticals (Basel) 2023; 16:1127. [PMID: 37631042 PMCID: PMC10458693 DOI: 10.3390/ph16081127] [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: 07/04/2023] [Revised: 08/03/2023] [Accepted: 08/09/2023] [Indexed: 08/27/2023] Open
Abstract
The metabotropic glutamate receptor subtype 5 (mGluR5) is a class C G-protein-coupled receptor (GPCR) that has been implicated in various neuronal processes and, consequently, in several neuropsychiatric or neurodevelopmental disorders. Over the past few decades, mGluR5 has become a major focus for pharmaceutical companies, as an attractive target for drug development, particularly through the therapeutic potential of its modulators. In particular, allosteric binding sites have been targeted for better specificity and efficacy. In this context, Positron Emission Tomography (PET) appears as a useful tool for making decisions along a drug candidate's development process, saving time and money. Thus, PET provides quantitative information about a potential drug candidate and its target at the molecular level. However, in this area, particular attention has to be given to the interpretation of the PET signal and its conclusions. Indeed, the complex pharmacology of both mGluR5 and radioligands, allosterism, the influence of endogenous glutamate and the choice of pharmacokinetic model are all factors that may influence the PET signal. This review focuses on mGluR5 PET radioligands used at several stages of central nervous system drug development, highlighting advances and setbacks related to the complex pharmacology of these radiotracers.
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Affiliation(s)
- Anne-Claire Dupont
- Radiopharmacie, CHRU de Tours, 37000 Tours, France
- UMR 1253, iBrain, Tours University, INSERM, 37000 Tours, France
| | - Nicolas Arlicot
- Radiopharmacie, CHRU de Tours, 37000 Tours, France
- UMR 1253, iBrain, Tours University, INSERM, 37000 Tours, France
- CIC 1415, Tours University, INSERM, 37000 Tours, France
| | | | - Sophie Serrière
- UMR 1253, iBrain, Tours University, INSERM, 37000 Tours, France
| | - Serge Maia
- Radiopharmacie, CHRU de Tours, 37000 Tours, France
- UMR 1253, iBrain, Tours University, INSERM, 37000 Tours, France
| | - Frédérique Bonnet-Brilhault
- UMR 1253, iBrain, Tours University, INSERM, 37000 Tours, France
- Excellence Center for Autism and Neurodevelopmental Disorders, CHRU de Tours, 37000 Tours, France
| | - Maria-Joao Santiago-Ribeiro
- UMR 1253, iBrain, Tours University, INSERM, 37000 Tours, France
- Nuclear Medicine Department, CHRU de Tours, 37000 Tours, France
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Zhou YP, Makaravage KJ, Brugarolas P. Radiolabeling with [ 11C]HCN for Positron emission tomography. Nucl Med Biol 2021; 102-103:56-86. [PMID: 34624831 PMCID: PMC8978408 DOI: 10.1016/j.nucmedbio.2021.09.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 08/20/2021] [Accepted: 09/20/2021] [Indexed: 12/22/2022]
Abstract
Hydrogen cyanide (HCN) is a versatile synthon for generating carbon‑carbon and carbon-heteroatom bonds. Unlike other one-carbon synthons (i.e., CO, CO2), HCN can function as a nucleophile (as in potassium cyanide, KCN) and an electrophile (as in cyanogen bromide, (CN)Br). The incorporation of the CN motif into organic molecules generates nitriles, hydantoins and (thio)cyanates, which can be converted to carboxylic acids, aldehydes, amides and amines. Such versatile chemistry is particularly attractive in PET radiochemistry where diverse bioactive small molecules incorporating carbon-11 in different positions need to be produced. The first examples of making [11C]HCN for radiolabeling date back to the 1960s. During the ensuing decades, [11C]cyanide labeling was popular for producing biologically important molecules including 11C-labeled α-amino acids, sugars and neurotransmitters. [11C]cyanation is now reemerging in many PET centers due to its versatility for making novel tracers. Here, we summarize the chemistry of [11C]HCN, review the methods to make [11C]HCN past and present, describe methods for labeling different types of molecules with [11C]HCN, and provide an overview of the reactions available to convert nitriles into other functional groups. Finally, we discuss some of the challenges and opportunities in [11C]HCN labeling such as developing more robust methods to produce [11C]HCN and developing rapid and selective methods to convert nitriles into other functional groups in complex molecules.
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Affiliation(s)
- Yu-Peng Zhou
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
| | - Katarina J Makaravage
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
| | - Pedro Brugarolas
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States.
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Lam J, DuBois JM, Rowley J, Rousset OG, González-Otárula KA, Soucy JP, Massarweh G, Hall JA, Guiot MC, Zimmermann M, Minuzzi L, Rosa-Neto P, Kobayashi E. In vivo hippocampal cornu ammonis 1-3 glutamatergic abnormalities are associated with temporal lobe epilepsy surgery outcomes. Epilepsia 2021; 62:1559-1568. [PMID: 34060082 DOI: 10.1111/epi.16952] [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: 01/28/2021] [Revised: 05/11/2021] [Accepted: 05/12/2021] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Previous positron emission tomography (PET) studies using [11 C]ABP688 show reduced metabotropic glutamate receptor type 5 (mGluR5) allosteric binding site availability in the epileptogenic hippocampus of mesial temporal lobe epilepsy (MTLE) patients. However, the link between mGluR5 abnormalities and postsurgical outcomes remains unclear. Here, we test whether reduced PET [11 C]ABP688 binding in cornu ammonis (CA) sectors more vulnerable to glutamatergic excitotoxicity relates to surgical outcomes. METHODS We obtained magnetic resonance imaging (MRI) and [11 C]ABP688-PET from 31 unilateral MTLE patients and 30 healthy controls. MRI hippocampal subfields were segmented using FreeSurfer. To respect the lower PET special resolution, MRI-derived anatomical subfields were combined into CA1-3, CA4/dentate gyrus, and Subiculum. Partial volume corrected [11 C]ABP688 nondisplaceable binding potential (BPND ) values were averaged across each subfield, and Z-scores were calculated. Subfield [11 C]ABP688-BPND was compared between seizure-free and non-seizure-free patients. In addition, we also assessed subfield volumes and [18 F]fluorodeoxyglucose (FDG) uptake in each clinical group. RESULTS MTLE [11 C]ABP688-BPND was reduced in ipsilateral (epileptogenic) CA1-3 and CA4/dentate-gyrus (p < .001, 95% confidence interval [CI] = .29-.51) compared to controls, with no difference in Subiculum. [11 C]ABP688-BPND and subfield volumes were compared between seizure-free (Engel IA, n = 13) and non-seizure-free patients (Engel IC-III, n = 10). In ipsilateral CA1-3 only, [11 C]ABP688-BPND was lower in seizure-free patients than in non-seizure-free patients (p = .012, 95% CI = 1.46-11.0) independently of volume. A subset analysis of 12 patients with [11 C]ABP688-PET+[18 F]FDG-PET showed no between-group significant difference in [18 F]FDG uptake, whereas CA1-3 [11 C]ABP688-BPND remained significantly lower in the seven of 12 seizure-free patients (p = .03, 95% CI = -3.13 to -.21). SIGNIFICANCE Reduced mGluR5 allosteric site availability in hippocampal CA1-3, measured in vivo by [11 C]ABP688-PET, is associated with postsurgery seizure freedom independent of atrophy or hypometabolism. Information derived from hippocampal CA1-3 [11 C]ABP688-PET is a promising imaging biomarker potentially impactful in surgical decisions for MRI-negative/PET-negative MTLE patients.
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Affiliation(s)
- Jack Lam
- Department of Neurology and Neurosurgery, Montréal Neurological Institute, McGill University, Montréal, Québec, Canada
| | - Jonathan M DuBois
- Department of Neurology and Neurosurgery, Montréal Neurological Institute, McGill University, Montréal, Québec, Canada
| | - Jared Rowley
- Translational Neuroimaging Laboratory, McGill University, Montréal, Québec, Canada
| | - Olivier G Rousset
- Division of Nuclear Medicine and Molecular Imaging, Johns Hopkins University, Baltimore, Maryland, USA
| | - Karina A González-Otárula
- Department of Neurology and Neurosurgery, Montréal Neurological Institute, McGill University, Montréal, Québec, Canada
| | - Jean-Paul Soucy
- Department of Neurology and Neurosurgery, Montréal Neurological Institute, McGill University, Montréal, Québec, Canada.,PET Unit, McConnell Brain Imaging Centre, McGill University, Montréal, Québec, Canada
| | - Gassan Massarweh
- PET Unit, McConnell Brain Imaging Centre, McGill University, Montréal, Québec, Canada
| | - Jeffery A Hall
- Department of Neurology and Neurosurgery, Montréal Neurological Institute, McGill University, Montréal, Québec, Canada
| | - Marie-Christine Guiot
- Department of Pathology, Montreal Neurological Institute, McGill University, Montréal, Québec, Canada
| | - Maria Zimmermann
- Department of Neurology and Neurosurgery, Montréal Neurological Institute, McGill University, Montréal, Québec, Canada
| | - Luciano Minuzzi
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada
| | - Pedro Rosa-Neto
- Department of Neurology and Neurosurgery, Montréal Neurological Institute, McGill University, Montréal, Québec, Canada.,Translational Neuroimaging Laboratory, McGill University, Montréal, Québec, Canada.,PET Unit, McConnell Brain Imaging Centre, McGill University, Montréal, Québec, Canada
| | - Eliane Kobayashi
- Department of Neurology and Neurosurgery, Montréal Neurological Institute, McGill University, Montréal, Québec, Canada
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