1
|
Wang J, Moon SH, Cleary MB, Shoup TM, El Fakhri G, Zhang Z, Brownell AL. Detailed radiosynthesis of [ 18 F]mG4P027 as a positron emission tomography radiotracer for mGluR4. J Labelled Comp Radiopharm 2023; 66:34-40. [PMID: 36593743 PMCID: PMC9985952 DOI: 10.1002/jlcr.4011] [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: 11/22/2022] [Revised: 12/25/2022] [Accepted: 12/29/2022] [Indexed: 01/04/2023]
Abstract
We report here the detailed radiosynthesis of [18 F]mG4P027, a metabotropic glutamate receptor 4 (mGluR4) PET radiotracer, which showed superior properties to the currently reported mGluR4 radiotracers. The radiosynthesis in the automated system has been challenging, therefore we disclose here the major limiting factors for the synthesis via step-by-step examination. And we hope this thorough study will help its automation for human use in the future.
Collapse
Affiliation(s)
| | | | - Michael B. Cleary
- Martinos Center for Biomedical Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, MA 02114 (USA)
| | | | | | - Zhaoda Zhang
- Martinos Center for Biomedical Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, MA 02114 (USA)
| | | |
Collapse
|
2
|
Vibholm AK, Dietz MJ, Beniczky S, Christensen J, Højlund A, Jacobsen J, Bender D, Møller A, Brooks DJ. Activated N-methyl-D-aspartate receptor ion channels detected in focal epilepsy with [ 18 F]GE-179 positron emission tomography. Epilepsia 2021; 62:2899-2908. [PMID: 34558066 DOI: 10.1111/epi.17074] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 09/03/2021] [Accepted: 09/03/2021] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Imaging activated glutamate N-methyl-D-aspartate receptor ion channels (NMDAR-ICs) using positron emission tomography (PET) has proved challenging due to low brain uptake, poor affinity and selectivity, and high metabolism and dissociation rates of candidate radioligands. The radioligand [18 F]GE-179 is a known use-dependent marker of NMDAR-ICs. We studied whether interictal [18 F]GE-179 PET would detect foci of abnormal NMDAR-IC activation in patients with refractory focal epilepsy. METHODS Ten patients with refractory focal epilepsy and 18 healthy controls had structural magnetic resonance imaging (MRI) followed by a 90-min dynamic [18 F]GE-179 PET scan with simultaneous electroencephalography (EEG). PET and EEG findings were compared with MRI and previous EEGs. Standard uptake value (SUV) images of [18 F]GE-179 were generated and global gray matter uptake was measured for each individual. To localize focal increases in uptake of [18 F]GE-179, the individual SUV images were interrogated with statistical parametric mapping in comparison to a normal database. Additionally, individual healthy control SUV images were compared with the rest of the control database to determine their prevalence of increased focal [18 F]GE-179 uptake. RESULTS Interictal [18 F]GE-179 PET detected clusters of significantly increased binding in eight of 10 patients with focal epilepsy but none of the controls. The number of clusters of raised [18 F]GE-179 uptake in the patients with epilepsy exceeded the focal abnormalities revealed by the simultaneously recorded EEG. Patients with extensive clusters of raised [18 F]GE-179 uptake showed the most abnormal EEGs. SIGNIFICANCE Detection of multiple foci of abnormal NMDAR-IC activation in 80% of our patients with refractory focal epilepsy using interictal [18 F]GE-179 PET could reflect enhanced neuronal excitability due to chronic seizure activity. This indicates that chronic epileptic activity is associated with abnormal NMDAR ion channel activation beyond the initial irritative zones. [18 F]GE-179 PET could be a candidate marker for identifying pathological brain areas in patients with treatment-resistant focal epilepsy.
Collapse
Affiliation(s)
- Ali K Vibholm
- Department of Nuclear Medicine and PET Center, Institute of Clinical Medicine, Aarhus University and University Hospital, Aarhus, Denmark
| | - Martin J Dietz
- Center of Functionally Integrative Neuroscience, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Sándor Beniczky
- Department of Clinical Neurophysiology, Danish Epilepsy Center and Aarhus University, Dianalund, Denmark
| | - Jakob Christensen
- Department of Neurology, Aarhus University Hospital, Aarhus, Denmark.,National Center for Register-Based Research, Department of Economics and Business Economics, School of Business and Social Sciences, Aarhus University, Aarhus, Denmark
| | - Andreas Højlund
- Center of Functionally Integrative Neuroscience, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Jan Jacobsen
- Department of Nuclear Medicine and PET Center, Institute of Clinical Medicine, Aarhus University and University Hospital, Aarhus, Denmark
| | - Dirk Bender
- Department of Nuclear Medicine and PET Center, Institute of Clinical Medicine, Aarhus University and University Hospital, Aarhus, Denmark
| | - Arne Møller
- Department of Nuclear Medicine and PET Center, Institute of Clinical Medicine, Aarhus University and University Hospital, Aarhus, Denmark.,Center of Functionally Integrative Neuroscience, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - David J Brooks
- Department of Nuclear Medicine and PET Center, Institute of Clinical Medicine, Aarhus University and University Hospital, Aarhus, Denmark.,Translational and Clinical Research Institute, Newcastle University, Newcastle Upon Tyne, UK
| |
Collapse
|
3
|
Vibholm AK, Landau AM, Møller A, Jacobsen J, Vang K, Munk OL, Orlowski D, Sørensen JC, Brooks DJ. NMDA receptor ion channel activation detected in vivo with [ 18F]GE-179 PET after electrical stimulation of rat hippocampus. J Cereb Blood Flow Metab 2021; 41:1301-1312. [PMID: 32960687 PMCID: PMC8142139 DOI: 10.1177/0271678x20954928] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The positron emission tomography (PET) tracer [18F]GE-179 binds to the phencyclidine (PCP) site in the open N-methyl-D-aspartate receptor ion channel (NMDAR-IC). To demonstrate that PET can visualise increased [18F]GE-179 uptake by active NMDAR-ICs and that this can be blocked by the PCP antagonist S-ketamine, 15 rats had an electrode unilaterally implanted in their ventral hippocampus. Seven rats had no stimulation, five received pulsed 400 µA supra-threshold 60 Hz stimulation alone, and three received intravenous S-ketamine injection prior to stimulation. Six other rats were not implanted. Each rat had a 90 min [18F]GE-179 PET scan. Stimulated rats had simultaneous depth-EEG recordings of induced seizure activity. [18F]GE-179 uptake (volume of distribution, VT) was compared between hemispheres and between groups. Electrical stimulation induced a significant increase in [18F]GE-179 uptake at the electrode site compared to the contralateral hippocampus (mean 22% increase in VT, p = 0.0014) and to non-stimulated comparator groups. Rats injected with S-ketamine prior to stimulation maintained non-stimulated levels of [18F]GE-179 uptake during stimulation. In conclusion, PET visualisation of focal [18F]GE-179 uptake during electrically activated NMDAR-ICs and the demonstration of specificity for PCP sites by blockade with S-ketamine support the in vivo utility of [18F]GE-179 PET as a use-dependent marker of NMDAR-IC activation.
Collapse
Affiliation(s)
- Ali K Vibholm
- Department of Nuclear Medicine & PET Centre, Aarhus University Hospital, Aarhus, Denmark
| | - Anne M Landau
- Department of Nuclear Medicine & PET Centre, Aarhus University Hospital, Aarhus, Denmark.,Translational Neuropsychiatry Unit, Aarhus University, Aarhus, Denmark
| | - Arne Møller
- Department of Nuclear Medicine & PET Centre, Aarhus University Hospital, Aarhus, Denmark.,Centre of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark
| | - Jan Jacobsen
- Department of Nuclear Medicine & PET Centre, Aarhus University Hospital, Aarhus, Denmark
| | - Kim Vang
- Department of Nuclear Medicine & PET Centre, Aarhus University Hospital, Aarhus, Denmark
| | - Ole L Munk
- Department of Nuclear Medicine & PET Centre, Aarhus University Hospital, Aarhus, Denmark
| | - Dariusz Orlowski
- Department of Neurosurgery and CENSE, Aarhus University Hospital, Aarhus, Denmark
| | - Jens Ch Sørensen
- Department of Neurosurgery and CENSE, Aarhus University Hospital, Aarhus, Denmark
| | - David J Brooks
- Department of Nuclear Medicine & PET Centre, Aarhus University Hospital, Aarhus, Denmark.,Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK
| |
Collapse
|
4
|
Kim JH, Marton J, Ametamey SM, Cumming P. A Review of Molecular Imaging of Glutamate Receptors. Molecules 2020; 25:molecules25204749. [PMID: 33081223 PMCID: PMC7587586 DOI: 10.3390/molecules25204749] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 10/13/2020] [Accepted: 10/14/2020] [Indexed: 12/22/2022] Open
Abstract
Molecular imaging with positron emission tomography (PET) and single photon emission computed tomography (SPECT) is a well-established and important in vivo technique to evaluate fundamental biological processes and unravel the role of neurotransmitter receptors in various neuropsychiatric disorders. Specific ligands are available for PET/SPECT studies of dopamine, serotonin, and opiate receptors, but corresponding development of radiotracers for receptors of glutamate, the main excitatory neurotransmitter in mammalian brain, has lagged behind. This state of affairs has persisted despite the central importance of glutamate neurotransmission in brain physiology and in disorders such as stroke, epilepsy, schizophrenia, and neurodegenerative diseases. Recent years have seen extensive efforts to develop useful ligands for molecular imaging of subtypes of the ionotropic (N-methyl-D-aspartate (NMDA), kainate, and AMPA/quisqualate receptors) and metabotropic glutamate receptors (types I, II, and III mGluRs). We now review the state of development of radioligands for glutamate receptor imaging, placing main emphasis on the suitability of available ligands for reliable in vivo applications. We give a brief account of the radiosynthetic approach for selected molecules. In general, with the exception of ligands for the GluN2B subunit of NMDA receptors, there has been little success in developing radiotracers for imaging ionotropic glutamate receptors; failure of ligands for the PCP/MK801 binding site in vivo doubtless relates their dependence on the open, unblocked state of the ion channel. Many AMPA and kainite receptor ligands with good binding properties in vitro have failed to give measurable specific binding in the living brain. This may reflect the challenge of developing brain-penetrating ligands for amino acid receptors, compounded by conformational differences in vivo. The situation is better with respect to mGluR imaging, particularly for the mGluR5 subtype. Several successful PET ligands serve for investigations of mGluRs in conditions such as schizophrenia, depression, substance abuse and aging. Considering the centrality and diversity of glutamatergic signaling in brain function, we have relatively few selective and sensitive tools for molecular imaging of ionotropic and metabotropic glutamate receptors. Further radiopharmaceutical research targeting specific subtypes and subunits of the glutamate receptors may yet open up new investigational vistas with broad applications in basic and clinical research.
Collapse
Affiliation(s)
- Jong-Hoon Kim
- Neuroscience Research Institute, Gachon University, Incheon 21565, Korea
- Gachon Advanced Institute for Health Science and Technology, Graduate School, Incheon 21565, Korea
- Department of Psychiatry, Gil Medical Center, Gachon University College of Medicine, Gachon University, Incheon 21565, Korea
- Correspondence: (J.-H.K.); (P.C.); Tel.: +41-31-664-0498 (P.C.); Fax: +41-31-632-7663 (P.C.)
| | - János Marton
- ABX Advanced Biochemical Compounds, Biomedizinische Forschungsreagenzien GmbH, Heinrich-Glaeser-Strasse 10-14, D-1454 Radeberg, Germany;
| | - Simon Mensah Ametamey
- Centre for Radiopharmaceutical Sciences ETH-PSI-USZ, Institute of Pharmaceutical Sciences ETH, Vladimir-Prelog-Weg 4, CH-8093 Zürich, Switzerland;
| | - Paul Cumming
- Department of Nuclear Medicine, University of Bern, Inselspital, Freiburgstrasse 18, CH-3010 Bern, Switzerland
- School of Psychology and Counselling, Queensland University of Technology, Brisbane QLD 4059, Australia
- Correspondence: (J.-H.K.); (P.C.); Tel.: +41-31-664-0498 (P.C.); Fax: +41-31-632-7663 (P.C.)
| |
Collapse
|
5
|
Activation of NMDA receptor ion channels by deep brain stimulation in the pig visualised with [18F]GE-179 PET. Brain Stimul 2020; 13:1071-1078. [DOI: 10.1016/j.brs.2020.03.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Revised: 03/17/2020] [Accepted: 03/30/2020] [Indexed: 11/20/2022] Open
|
6
|
Khan I, Berg TC, Brown J, Bhalla R, Wilson A, Black A, McRobbie G, Nairne J, Olsson A, Trigg W. Development of an automated, GMP compliant FASTlab™ radiosynthesis of [ 18 F]GE-179 for the clinical study of activated NMDA receptors. J Labelled Comp Radiopharm 2020; 63:183-195. [PMID: 31986223 DOI: 10.1002/jlcr.3831] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 01/08/2020] [Accepted: 01/20/2020] [Indexed: 07/25/2024]
Abstract
N-(2-chloro-5-(S-2-[18 F]fluoroethyl)thiophenyl)-N'-(3-thiomethylphenyl)-N'-methylguanidine, ([18 F]GE-179), has been identified as a promising positron emission tomography (PET) ligand for the intra-channel phencyclidine (PCP) binding site of the N-methyl-D-aspartate (NMDA) receptor. The radiosynthesis of [18 F]GE-179 has only been performed at low radioactivity levels. However, the manufacture of a GMP compliant product at high radioactivity levels was required for clinical studies. We describe the development of a process using the GE FASTlab™ radiosynthesis platform coupled with HPLC purification. The radiosynthesis is a two-step process, involving the nucleophilic fluorination of ethylene ditosylate, 11, followed by alkylation to the deprotonated thiol precursor, N-(2-chloro-5-thiophenol)-N'-(3-thiomethylphenyl)-N'-methyl guanidine, 8. The crude product was purified by semi-preparative HPLC to give the formulated product in an activity yield (AY) of 7 ± 2% (n = 15) with a total synthesis time of 120 minutes. The radioactive concentration (RAC) and radiochemical purity (RCP) were 328 ± 77 MBq/mL and 96.5 ± 1% respectively and the total chemical content was 2 ± 1 μg. The final formulation volume was 14 mL. The previously described radiosynthesis of [18 F]GE-179 was successfully modified to deliver an process on the FASTlab™ that allows the manufacture of a GMP quality product from high starting radioactivitity (up to 80 GBq) and delivers a product suitable for clinical use.
Collapse
Affiliation(s)
- Imtiaz Khan
- Core Imaging R&D, Life Sciences, GE Healthcare, Chalfont St Giles, Bucks, UK
| | | | - Jane Brown
- Core Imaging R&D, Life Sciences, GE Healthcare, Chalfont St Giles, Bucks, UK
| | - Rajiv Bhalla
- Core Imaging R&D, Life Sciences, GE Healthcare, Chalfont St Giles, Bucks, UK
| | - Anthony Wilson
- Core Imaging R&D, Life Sciences, GE Healthcare, Chalfont St Giles, Bucks, UK
| | - Andrew Black
- Core Imaging R&D, Life Sciences, GE Healthcare, Chalfont St Giles, Bucks, UK
| | - Graeme McRobbie
- Core Imaging R&D, Life Sciences, GE Healthcare, Chalfont St Giles, Bucks, UK
| | - James Nairne
- Core Imaging R&D, Life Sciences, GE Healthcare, Chalfont St Giles, Bucks, UK
| | - Andreas Olsson
- Core Imaging R&D, Life Sciences, GE Healthcare, Oslo, Norway
| | - William Trigg
- Core Imaging R&D, Life Sciences, GE Healthcare, Chalfont St Giles, Bucks, UK
| |
Collapse
|
7
|
Automated production of a N-methyl-D-aspartate receptor radioligand [ 18F]GE179 for clinical use. Appl Radiat Isot 2019; 148:246-252. [PMID: 31026789 DOI: 10.1016/j.apradiso.2019.03.035] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Revised: 02/01/2019] [Accepted: 03/25/2019] [Indexed: 11/20/2022]
Abstract
N-Methyl-d-aspartate (NMDA) receptors are ligand and voltage-gated heteromeric ion channel receptors. Excessive activation of NMDA receptors is implicated in many neurological and psychiatric disorders, including ischemic stroke, neuropathic pain, epilepsy, drug addition, Alzheimer's disease, and schizophrenia. [18F]GE179 is a promising PET probe for imaging functional NMDA receptor alterations (activated or 'open' channel) with a high binding affinity (Kd = 2.4 nM). Here, we report the production of the NMDA receptor radioligand [18F]GE179 in a current Good Manufacturing Practice (cGMP) facility through a one-pot two-step strategy. [18F]GE179 was produced in approximately 110 min with a radiochemical yield of 12 ± 6% (n = 4, decay corrected), radiochemical purity >95%, molar activity of 146 ± 32 GBq/μmol (at the end of synthesis), an average mass of GE179 at 2.2 μg/batch, and total impurities less than 0.5 μg/batch (n = 4). The radiopharmaceutical dose meets all quality control (QC) criteria for human use, and is suitable for clinical PET studies of activated NMDA receptor ion channels.
Collapse
|
8
|
Radiotracers for imaging of Parkinson's disease. Eur J Med Chem 2019; 166:75-89. [DOI: 10.1016/j.ejmech.2019.01.029] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 01/12/2019] [Accepted: 01/13/2019] [Indexed: 12/22/2022]
|
9
|
Metaxas A, van Berckel BNM, Klein PJ, Verbeek J, Nash EC, Kooijman EJM, Renjaän VA, Golla SSV, Boellaard R, Christiaans JAM, Windhorst AD, Leysen JE. Binding characterization of N-(2-chloro-5-thiomethylphenyl)-N'-(3-[ 3 H] 3 methoxy phenyl)-N'-methylguanidine ([ 3 H]GMOM), a non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist. Pharmacol Res Perspect 2019; 7:e00458. [PMID: 30784206 PMCID: PMC6381215 DOI: 10.1002/prp2.458] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 12/01/2018] [Accepted: 12/06/2018] [Indexed: 01/18/2023] Open
Abstract
Labeled with carbon‐11, N‐(2‐chloro‐5‐thiomethylphenyl)‐N′‐(3‐methoxyphenyl)‐N′‐methylguanidine ([11C]GMOM) is currently the only positron emission tomography (PET) tracer that has shown selectivity for the ion‐channel site of N‐methyl‐D‐aspartate (NMDA) receptors in human imaging studies. The present study reports on the selectivity profile and in vitro binding properties of GMOM. The compound was screened on a panel of 80 targets, and labeled with tritium ([3H]GMOM). The binding properties of [3H]GMOM were compared to those of the reference ion‐channel ligand [3H](+)‐dizocilpine maleate ([3H]MK‐801), in a set of concentration‐response, homologous and heterologous inhibition, and association kinetics assays, performed with repeatedly washed rat forebrain preparations. GMOM was at least 70‐fold more selective for NMDA receptors compared to all other targets examined. In homologous inhibition and concentration‐response assays, the binding of [3H]GMOM was regulated by NMDA receptor agonists, albeit in a less prominent manner compared to [3H]MK‐801. Scatchard transformation of homologous inhibition data produced concave upward curves for [3H]GMOM and [3H]MK‐801. The radioligands showed bi‐exponential association kinetics in the presence of 100 μmol L−1l‐glutamate/30 μmol L−1 glycine. [3H]GMOM (3 nmol L−1 and 10 nmol L−1) was inhibited with dual affinity by (+)‐MK‐801, (R,S)‐ketamine and memantine, in both presence and absence of agonists. [3H]MK‐801 (2 nmol L−1) was inhibited in a monophasic manner by GMOM under baseline and combined agonist conditions, with an IC50 value of ~19 nmol L−1. The non‐linear Scatchard plots, biphasic inhibition by open channel blockers, and bi‐exponential kinetics of [3H]GMOM indicate a complex mechanism of interaction with the NMDA receptor ionophore. The implications for quantifying the PET signal of [11C]GMOM are discussed.
Collapse
Affiliation(s)
- Athanasios Metaxas
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, Amsterdam, the Netherlands
| | - Bart N M van Berckel
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, Amsterdam, the Netherlands
| | - Pieter J Klein
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, Amsterdam, the Netherlands
| | - Joost Verbeek
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, Amsterdam, the Netherlands
| | - Emily C Nash
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, Amsterdam, the Netherlands
| | - Esther J M Kooijman
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, Amsterdam, the Netherlands
| | - Véronique A Renjaän
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, Amsterdam, the Netherlands
| | - Sandeep S V Golla
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, Amsterdam, the Netherlands
| | - Ronald Boellaard
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, Amsterdam, the Netherlands
| | - Johannes A M Christiaans
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, Amsterdam, the Netherlands
| | - Albert D Windhorst
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, Amsterdam, the Netherlands
| | - Josée E Leysen
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, Amsterdam, the Netherlands
| |
Collapse
|
10
|
Fu H, Chen Z, Josephson L, Li Z, Liang SH. Positron Emission Tomography (PET) Ligand Development for Ionotropic Glutamate Receptors: Challenges and Opportunities for Radiotracer Targeting N-Methyl-d-aspartate (NMDA), α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid (AMPA), and Kainate Receptors. J Med Chem 2019; 62:403-419. [PMID: 30110164 PMCID: PMC6393217 DOI: 10.1021/acs.jmedchem.8b00714] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Ionotropic glutamate receptors (iGluRs) mediate excitatory neurotransmission within the mammalian central nervous system. iGluRs exist as three main groups: N-methyl-d-aspartate receptors (NMDARs), α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs), and kainate receptors. The past decades have witnessed a remarkable development of PET tracers targeting different iGluRs including NMDARs and AMPARs, and several of the tracers have advanced to clinical imaging studies. Here, we assess the recent development of iGluR PET probes, focusing on tracer design, brain kinetics, and performance in PET imaging studies. Furthermore, this review will not only present challenges in the tracer development but also provide novel approaches in conjunction with most recent drug discovery efforts on these iGluRs, including subtype-selective NMDAR and transmembrane AMPAR regulatory protein modulators and positive allosteric modulators (PAMs) of AMPARs. These approaches, if successful as PET tracers, may provide fundamental knowledge to understand the roles of iGluR receptors under physiological and pathological conditions.
Collapse
Affiliation(s)
- Hualong Fu
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 55 Fruit St., Boston, MA 02114 USA
| | - Zhen Chen
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 55 Fruit St., Boston, MA 02114 USA
| | - Lee Josephson
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 55 Fruit St., Boston, MA 02114 USA
| | - Zijing Li
- State Key Laboratory of Molecular Vaccinology, Molecular Diagnosis & Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361102, P. R. China
| | - Steven H. Liang
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 55 Fruit St., Boston, MA 02114 USA
| |
Collapse
|
11
|
McGinnity CJ, Årstad E, Beck K, Brooks DJ, Coles JP, Duncan JS, Galovic M, Hinz R, Hirani E, Howes OD, Jones PA, Koepp MJ, Luo F, Riaño Barros DA, Singh N, Trigg W, Hammers A. Comment on " In Vivo [ 18F]GE-179 Brain Signal Does Not Show NMDA-Specific Modulation with Drug Challenges in Rodents and Nonhuman Primates". ACS Chem Neurosci 2019; 10:768-772. [PMID: 30346706 DOI: 10.1021/acschemneuro.8b00246] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Schoenberger and colleagues ( Schoenberger et al. ( 2018 ) ACS Chem. Neurosci. 9 , 298 - 305 ) recently reported attempts to demonstrate specific binding of the positron emission tomography (PET) radiotracer, [18F]GE-179, to NMDA receptors in both rats and Rhesus macaques. GE-179 did not work as expected in animal models; however, we disagree with the authors' conclusion that "the [18F]GE-179 signal seems to be largely nonspecific". It is extremely challenging to demonstrate specific binding for the use-dependent NMDA receptor intrachannel ligands such as [18F]GE-179 in animals via traditional blocking, due to its low availability of target sites ( Bmax'). Schoenberger and colleagues anesthetized rats and Rhesus monkeys using isoflurane, which has an inhibitory effect on NMDA receptor function and thus would be expected to further reduce the Bmax'. The extent of glutamate release achieved in the provocation experiments is uncertain, as is whether a significant increase in NMDA receptor channel opening can be expected under anesthesia. Prior data suggest that the uptake of disubstituted arylguanidine-based ligands such as GE-179 can be reduced by phencyclidine binding site antagonists, if injection is performed in the absence of ketamine and isoflurane anesthesia, e.g., with GE-179's antecedent, CNS 5161 ( Biegon et al. ( 2007 ) Synapse 61 , 577 - 586 ), and with GMOM ( van der Doef et al. ( 2016 ) J. Cereb. Blood Flow Metab. 36 , 1111 - 1121 ). However, the extent of nonspecific uptake remains uncertain.
Collapse
Affiliation(s)
- Colm J. McGinnity
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London SE1 7EH, United Kingdom
- King’s
College London & Guy’s and St Thomas’ PET Centre,
St Thomas’ Hospital, London SE1 7EH, United Kingdom
| | - Erik Årstad
- Institute of Nuclear Medicine and Department of Chemistry, University College London, London NW1 2BU, United Kingdom
| | - Katherine Beck
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London SE5 8AF, United Kingdom
| | - David J. Brooks
- Department of Nuclear Medicine, Aarhus University, Aarhus 8200, Denmark
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne NE1 7RU, United Kingdom
| | - Jonathan P. Coles
- Division of Anaesthesia, Department of Medicine, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| | - John S. Duncan
- Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London WC1N 3BG, United Kingdom
- Epilepsy Society, Gerrards Cross SL9 0RJ, United Kingdom
| | - Marian Galovic
- Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London WC1N 3BG, United Kingdom
- Epilepsy Society, Gerrards Cross SL9 0RJ, United Kingdom
- Department of Neurology, Kantonsspital St Gallen, 9007 St. Gallen, Switzerland
| | - Rainer Hinz
- Wolfson Molecular Imaging Centre, University of Manchester, Manchester M20 3LJ, United Kingdom
| | - Ella Hirani
- GE Healthcare Ltd, Amersham HP7 9LL, United Kingdom
| | - Oliver D. Howes
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London SE5 8AF, United Kingdom
| | | | - Matthias J. Koepp
- Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London WC1N 3BG, United Kingdom
- Epilepsy Society, Gerrards Cross SL9 0RJ, United Kingdom
| | - Feng Luo
- GE Healthcare Ltd, Amersham HP7 9LL, United Kingdom
| | - Daniela A. Riaño Barros
- South London and Maudsley NHS Foundation Trust, Bethlem Royal Hospital, Beckenham, London BR3 3BX, United Kingdom
| | - Nisha Singh
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London SE1 7EH, United Kingdom
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London SE5 8AF, United Kingdom
| | | | - Alexander Hammers
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London SE1 7EH, United Kingdom
- King’s
College London & Guy’s and St Thomas’ PET Centre,
St Thomas’ Hospital, London SE1 7EH, United Kingdom
| |
Collapse
|
12
|
Lu Y, Choi JY, Kim SE, Lee BC. HPLC-free in situ18F-fluoromethylation of bioactive molecules by azidation and MTBD scavenging. Chem Commun (Camb) 2019; 55:11798-11801. [DOI: 10.1039/c9cc04901k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Sequential usage of azide and MTBD, which generates pure [18F]fluoromethyl tosylate and scavenges unreacted desmethyl precursors, provided an efficient HPLC-free strategy for the radio-synthesis of 18F-fluoromethylated compounds.
Collapse
Affiliation(s)
- Yingqing Lu
- Department of Nuclear Medicine
- Seoul National University College of Medicine
- Seoul National University Bundang Hospital
- Seongnam
- Republic of Korea
| | - Ji Young Choi
- Department of Nuclear Medicine
- Seoul National University College of Medicine
- Seoul National University Bundang Hospital
- Seongnam
- Republic of Korea
| | - Sang Eun Kim
- Department of Nuclear Medicine
- Seoul National University College of Medicine
- Seoul National University Bundang Hospital
- Seongnam
- Republic of Korea
| | - Byung Chul Lee
- Department of Nuclear Medicine
- Seoul National University College of Medicine
- Seoul National University Bundang Hospital
- Seongnam
- Republic of Korea
| |
Collapse
|
13
|
Huang MW, Lin YJ, Chang CW, Lei FJ, Ho EP, Liu RS, Shyu WC, Hsieh CH. RGS4 deficit in prefrontal cortex contributes to the behaviors related to schizophrenia via system x c--mediated glutamatergic dysfunction in mice. Am J Cancer Res 2018; 8:4781-4794. [PMID: 30279737 PMCID: PMC6160762 DOI: 10.7150/thno.25189] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Accepted: 04/09/2018] [Indexed: 01/08/2023] Open
Abstract
Rationale: Although molecular investigations of regulator of G-protein signaling 4 (RGS4) alterations in schizophrenia patients yielded partially inconsistent findings, the previous studies suggested that RGS4 is both a positional and functional candidate gene for schizophrenia and is significantly decreased in the prefrontal cortex. However, the exact role of RGS4 in the pathophysiology of schizophrenia is unclear. Moreover, a whole genome transcription profile study showed the possibility of RGS4-regulated expression of SLC7A11(xCT), a component of cysteine/glutamate transporter or system xc-. We hypothesized that system xc- is a therapeutic target of RGS4 deficit-mediated schizophrenia. Methods: Pharmacological and genetic manipulation of RGS4 in organotypic brain slice cultures were used as an ex vivo model to investigate its role in system xc- and glutamatergic function. Lentiviral-based mouse models with RGS4 deficit in the prefrontal cortex and treatment with system xc- activator, N-acetyl cysteine (NAC), were utilized to observe their impacts on glutamatergic function and schizophrenic behaviors. Results: Genetic and pharmacological inhibition of RGS4 resulted in a significant decrease in SLC7A11 (xCT) expression and hypofunction of system xc- and reduced glutamatergic function in organotypic brain slice cultures. However, NAC restored the dysregulation of RGS4-mediated functional deficits of glutamate. Moreover, knockdown of RGS4 specifically in the prefrontal cortex caused mice to exhibit behaviors related to schizophrenia such as increased stereotypy, impaired prepulse inhibition, deficits in social interactions, working memory, and nesting behavior, while enhancing sensitivity to the locomotor stimulatory effect of MK-801. These mice displayed glutamatergic dysfunction in the prefrontal cortex, which may have contributed to the behavioral deficits. RGS4 knockdown mice that received NAC treatment had improved glutamatergic dysfunction and schizophrenia behaviors. Conclusion: Our results suggest that RGS4 deficit induces dysregulation and dysfunction of system xc-, which further results in functional deficits of the glutamatergic system and subsequently to schizophrenia-related behavioral phenotypes. Activation of system xc- offers a promising strategy to treat RGS4 deficit-mediated schizophrenia.
Collapse
|
14
|
Zhou W, Bao W, Jiang D, Kong Y, Hua F, Lu X, Guan Y. [18F]-GE-179 positron emission tomography (PET) tracer for N-methyl-d-aspartate receptors: One-pot synthesis and preliminary micro-PET study in a rat model of MCAO. Nucl Med Biol 2018; 61:45-55. [DOI: 10.1016/j.nucmedbio.2018.04.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 03/14/2018] [Accepted: 04/10/2018] [Indexed: 12/23/2022]
|
15
|
Schoenberger M, Schroeder FA, Placzek MS, Carter RL, Rosen BR, Hooker JM, Sander CY. In Vivo [ 18F]GE-179 Brain Signal Does Not Show NMDA-Specific Modulation with Drug Challenges in Rodents and Nonhuman Primates. ACS Chem Neurosci 2018; 9:298-305. [PMID: 29050469 PMCID: PMC5894869 DOI: 10.1021/acschemneuro.7b00327] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
As one of the major excitatory ion channels in the brain, NMDA receptors have been a leading research target for neuroscientists, physicians, medicinal chemists, and pharmaceutical companies for decades. Molecular imaging of NMDA receptors by means of positron emission tomography (PET) with [18F]GE-179 quickly progressed to clinical PET studies, but a thorough understanding of its binding specificity has been missing and has thus limited signal interpretation. Here a preclinical study with [18F]GE-179 in rodents and nonhuman primates (NHPs) is presented in an attempt to characterize [18F]GE-179 signal specificity. Rodent PET/CT was used to study drug occupancy and functional manipulation in rats by pretreating animals with NMDA targeted blocking/modulating drug doses followed by a single bolus of [18F]GE-179. Binding competition with GE-179, MK801, PCP, and ketamine, allosteric inhibition by ifenprodil, and brain activation with methamphetamine did not alter the [18F]GE-179 brain signal in rats. In addition, multimodal imaging with PET/MRI in NHPs was used to evaluate changes in radiotracer binding as a function of pharmacological challenges. Drug-induced hemodynamic changes were monitored simultaneously using functional MRI (fMRI). Comparisons of baseline and signal after drug challenge in NHPs demonstrated that the [18F]GE-179 signal cannot be manipulated in a predictable fashion in vivo. fMRI data acquired simultaneously with PET data supported this finding and provided evidence that radiotracer delivery is not altered by blood flow changes. In conclusion, the [18F]GE-179 brain signal is not readily interpretable in the context of NMDA receptor binding on the basis of the results shown in this study.
Collapse
Affiliation(s)
- Matthias Schoenberger
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital , Charlestown, Massachusetts 02129, United States
- Chemical Biology and Imaging, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven , BE-3000 Leuven, Belgium
| | - Frederick A Schroeder
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital , Charlestown, Massachusetts 02129, United States
| | - Michael S Placzek
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital , Charlestown, Massachusetts 02129, United States
- Department of Psychiatry, McLean Imaging Center, McLean Hospital , Belmont, Massachusetts 02478, United States
- Harvard Medical School , Boston, Massachusetts 02115, United States
| | | | - Bruce R Rosen
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital , Charlestown, Massachusetts 02129, United States
- Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - Jacob M Hooker
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital , Charlestown, Massachusetts 02129, United States
- Harvard Medical School , Boston, Massachusetts 02115, United States
| | - Christin Y Sander
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital , Charlestown, Massachusetts 02129, United States
- Harvard Medical School , Boston, Massachusetts 02115, United States
| |
Collapse
|
16
|
Imaging the glutamate receptor subtypes-Much achieved, and still much to do. DRUG DISCOVERY TODAY. TECHNOLOGIES 2017; 25:27-36. [PMID: 29233264 DOI: 10.1016/j.ddtec.2017.10.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 10/17/2017] [Accepted: 10/24/2017] [Indexed: 11/20/2022]
Abstract
Functional imaging of glutamate receptors using PET imaging modality can be used to study numerous CNS disorders and also to select appropriate doses of clinically relevant glutamate-receptor-targeting candidate drugs. Great strides have been made in developing PET imaging probes for the non-invasive detection of glutamate receptors in the brain. This review highlights recent progress made towards the development of glutamatergic PET imaging agents. Focus is placed on PET imaging probes that have been labelled with either carbon-11 or fluorine-18.
Collapse
|
17
|
Klein PJ, Schuit RC, Metaxas A, Christiaans JAM, Kooijman E, Lammertsma AA, van Berckel BNM, Windhorst AD. Synthesis, radiolabeling and preclinical evaluation of a [ 11C]GMOM derivative as PET radiotracer for the ion channel of the N-methyl-D-aspartate receptor. Nucl Med Biol 2017; 51:25-32. [PMID: 28528265 DOI: 10.1016/j.nucmedbio.2017.05.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 03/29/2017] [Accepted: 05/04/2017] [Indexed: 12/22/2022]
Abstract
INTRODUCTION Presently available PET ligands for the NMDAr ion channel generally suffer from fast metabolism. The purpose of this study was to develop a metabolically more stable ligand for the NMDAr ion channel, taking [11C]GMOM ([11C]1) as the lead compound. METHODS [11C]1, its fluoralkyl analogue [18F]PK209 ([18F]2) and the newly synthesized fluorovinyloxy analogue [11C]7b were evaluated ex vivo in male Wistar rats for metabolic stability. In addition, [11C]7b was subjected to a biodistribution study and its affinity (Ki) and lipophilicity (logD7.4) values were determined. RESULTS The addition of a vinyl chain in the fluoromethoxy moiety did not negatively alter the affinity of [11C]7b for the NMDAr, while lipophilicity was increased. Biodistribution studies showed higher uptake of [11C]7b in forebrain regions compared with cerebellum. Pre-treatment with MK-801 decreased the overall brain uptake significantly, but not in a region-specific manner. 45min after injection 78, 90 and 87% of activity in the brain was due to parent compound for [11C]1, [18F]2 and [11C]7b, respectively. In plasma, 26-31% of activity was due to parent compound. CONCLUSION Complete substitution of the alpha-carbon increased lipophilicity to more favorable values. Substitution of one or more hydrogens of the alpha-carbon atom in the methoxy moiety improved metabolic stability. In plasma, more parent compound was found for [18F]2 and [11C]7b then for [11C]1, although differences were not significant. At 45min, significantly more parent [18F]2 and [11C]7b was measured in the brain compared with [11C]1.
Collapse
Affiliation(s)
- Pieter J Klein
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam, The Netherlands.
| | - Robert C Schuit
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam, The Netherlands
| | - Athanasios Metaxas
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam, The Netherlands
| | - Johannes A M Christiaans
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam, The Netherlands
| | - Esther Kooijman
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam, The Netherlands
| | - Adriaan A Lammertsma
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam, The Netherlands
| | - Bart N M van Berckel
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam, The Netherlands
| | - Albert D Windhorst
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam, The Netherlands
| |
Collapse
|
18
|
Kassenbrock A, Vasdev N, Liang SH. Selected PET Radioligands for Ion Channel Linked Neuroreceptor Imaging: Focus on GABA, NMDA and nACh Receptors. Curr Top Med Chem 2017; 16:1830-42. [PMID: 26975506 DOI: 10.2174/1568026616666160315142457] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Revised: 08/01/2015] [Accepted: 08/03/2015] [Indexed: 12/11/2022]
Abstract
Positron emission tomography (PET) neuroimaging of ion channel linked receptors is a developing area of preclinical and clinical research. The present review focuses on recent advances with radiochemistry, preclinical and clinical PET imaging studies of three receptors that are actively pursued in neuropsychiatric drug discovery: namely the γ-aminobutyric acid-benzodiazapine (GABA) receptor, nicotinic acetylcholine receptor (nAChR), and N-methyl-D-aspartate (NMDA) receptor. Recent efforts to develop new PET radioligands for these targets with improved brain uptake, selectivity, stability and pharmacokinetics are highlighted.
Collapse
Affiliation(s)
| | | | - Steven H Liang
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
| |
Collapse
|
19
|
van der Born D, Pees A, Poot AJ, Orru RVA, Windhorst AD, Vugts DJ. Fluorine-18 labelled building blocks for PET tracer synthesis. Chem Soc Rev 2017; 46:4709-4773. [DOI: 10.1039/c6cs00492j] [Citation(s) in RCA: 113] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
This review presents a comprehensive overview of the synthesis and application of fluorine-18 labelled building blocks since 2010.
Collapse
Affiliation(s)
- Dion van der Born
- Department of Radiology & Nuclear Medicine
- VU University Medical Center
- 1081 HV Amsterdam
- The Netherlands
| | - Anna Pees
- Department of Radiology & Nuclear Medicine
- VU University Medical Center
- 1081 HV Amsterdam
- The Netherlands
| | - Alex J. Poot
- Department of Radiology & Nuclear Medicine
- VU University Medical Center
- 1081 HV Amsterdam
- The Netherlands
| | - Romano V. A. Orru
- Department of Chemistry and Pharmaceutical Sciences and Amsterdam Institute for Molecules
- Medicines & Systems (AIMMS)
- VU University Amsterdam
- Amsterdam
- The Netherlands
| | - Albert D. Windhorst
- Department of Radiology & Nuclear Medicine
- VU University Medical Center
- 1081 HV Amsterdam
- The Netherlands
| | - Danielle J. Vugts
- Department of Radiology & Nuclear Medicine
- VU University Medical Center
- 1081 HV Amsterdam
- The Netherlands
| |
Collapse
|
20
|
Hsieh CH, Lin YJ, Chen WL, Huang YC, Chang CW, Cheng FC, Liu RS, Shyu WC. HIF-1α triggers long-lasting glutamate excitotoxicity via system x c- in cerebral ischaemia-reperfusion. J Pathol 2016; 241:337-349. [PMID: 27801527 DOI: 10.1002/path.4838] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 09/26/2016] [Accepted: 10/17/2016] [Indexed: 11/11/2022]
Abstract
Hypoxia-inducible factor 1α (HIF-1α) controls many genes involved in physiological and pathological processes. However, its roles in glutamatergic transmission and excitotoxicity are unclear. Here, we proposed that HIF-1α might contribute to glutamate-mediated excitotoxicity during cerebral ischaemia-reperfusion (CIR) and investigated its molecular mechanism. We showed that an HIF-1α conditional knockout mouse displayed an inhibition in CIR-induced elevation of extracellular glutamate and N-methyl-d-aspartate receptor (NMDAR) activation. By gene screening for glutamate transporters in cortical cells, we found that HIF-1α mainly regulates the cystine-glutamate transporter (system xc- ) subunit xCT by directly binding to its promoter; xCT and its function are up-regulated in the ischaemic brains of rodents and humans, and the effects lasted for several days. Genetic deletion of xCT in cortical cells of mice inhibits either oxygen glucose deprivation/reoxygenation (OGDR) or CIR-mediated glutamate excitotoxicity in vitro and in vivo. Pharmaceutical inhibition of system xc- by a clinically approved anti-cancer drug, sorafenib, improves infarct volume and functional outcome in rodents with CIR and its therapeutic window is at least 3 days. Taken together, these findings reveal that HIF-1α plays a role in CIR-induced glutamate excitotoxicity via the long-lasting activation of system xc- -dependent glutamate outflow and suggest that system xc- is a promising therapeutic target with an extended therapeutic window in stroke. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Collapse
Affiliation(s)
- Chia-Hung Hsieh
- Graduate Institute of Basic Medical Science, China Medical University, No 91, Hsueh-Shih Road, Taichung, Taiwan, 40402.,Department of Medical Research, China Medical University Hospital, No 2, Yuh-Der Road, Taichung, Taiwan, 40402.,Aging Medicine Program, China Medical University, No 91, Hsueh-Shih Road, Taichung, Taiwan, 40402.,Department of Biomedical Informatics, Asia University, No 500, Lioufeng Road, Taichung, Taiwan, 41354
| | - Yu-Jung Lin
- Graduate Institute of Basic Medical Science, China Medical University, No 91, Hsueh-Shih Road, Taichung, Taiwan, 40402
| | - Wei-Ling Chen
- Aging Medicine Program, China Medical University, No 91, Hsueh-Shih Road, Taichung, Taiwan, 40402
| | - Yen-Chih Huang
- Graduate Institute of Immunology, China Medical University, No 91, Hsueh-Shih Road, Taichung, Taiwan, 40402
| | - Chi-Wei Chang
- National PET/Cyclotron Center and Department of Nuclear Medicine, Taipei Veterans General Hospital, No 201, Shipai Road, Taipei, Taiwan, 11217
| | - Fu-Chou Cheng
- Stem Cell Center, Department of Medical Research, Taichung Veterans General Hospital, 1650 Taiwan Boulevard Section 4, Taichung, Taiwan, 40705
| | - Ren-Shyan Liu
- National PET/Cyclotron Center and Department of Nuclear Medicine, Taipei Veterans General Hospital, No 201, Shipai Road, Taipei, Taiwan, 11217
| | - Woei-Cherng Shyu
- Department of Neurology, Center for Neuropsychiatry, China Medical University and Hospital, No 91, Hsueh-Shih Road, Taichung, Taiwan, 40402
| |
Collapse
|
21
|
van der Doef TF, Golla SSV, Klein PJ, Oropeza-Seguias GM, Schuit RC, Metaxas A, Jobse E, Schwarte LA, Windhorst AD, Lammertsma AA, van Berckel BNM, Boellaard R. Quantification of the novel N-methyl-d-aspartate receptor ligand [11C]GMOM in man. J Cereb Blood Flow Metab 2016; 36:1111-21. [PMID: 26661185 PMCID: PMC4904354 DOI: 10.1177/0271678x15608391] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 06/26/2015] [Indexed: 11/17/2022]
Abstract
[(11)C]GMOM (carbon-11 labeled N-(2-chloro-5-thiomethylphenyl)-N'-(3-[(11)C]methoxy-phenyl)-N'-methylguanidine) is a PET ligand that binds to the N-methyl-d-aspartate receptor with high specificity and affinity. The purpose of this first in human study was to evaluate kinetics of [(11)C]GMOM in the healthy human brain and to identify the optimal pharmacokinetic model for quantifying these kinetics, both before and after a pharmacological dose of S-ketamine. Dynamic 90 min [(11)C]GMOM PET scans were obtained from 10 subjects. In six of the 10 subjects, a second PET scan was performed following an S-ketamine challenge. Metabolite corrected plasma input functions were obtained for all scans. Regional time activity curves were fitted to various single- and two-tissue compartment models. Best fits were obtained using a two-tissue irreversible model with blood volume parameter. The highest net influx rate (Ki) of [(11)C]GMOM was observed in regions with high N-methyl-d-aspartate receptor density, such as hippocampus and thalamus. A significant reduction in the Ki was observed for the entire brain after administration of ketamine, suggesting specific binding to the N-methyl-d-aspartate receptors. This initial study suggests that the [(11)C]GMOM could be used for quantification of N-methyl-d-aspartate receptors.
Collapse
Affiliation(s)
- Thalia F van der Doef
- Department of Radiology & Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands Department of Psychiatry, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Sandeep S V Golla
- Department of Radiology & Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - Pieter J Klein
- Department of Radiology & Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - Gisela M Oropeza-Seguias
- Department of Radiology & Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - Robert C Schuit
- Department of Radiology & Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - Athanasios Metaxas
- Department of Radiology & Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - Ellen Jobse
- Department of Radiology & Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - Lothar A Schwarte
- Department of Anesthesiology, VU University Medical Center, Amsterdam, The Netherlands
| | - Albert D Windhorst
- Department of Radiology & Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - Adriaan A Lammertsma
- Department of Radiology & Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - Bart N M van Berckel
- Department of Radiology & Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands Department of Psychiatry, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Ronald Boellaard
- Department of Radiology & Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| |
Collapse
|
22
|
López-Picón F, Snellman A, Shatillo O, Lehtiniemi P, Grönroos TJ, Marjamäki P, Trigg W, Jones PA, Solin O, Pitkänen A, Haaparanta-Solin M. Ex Vivo Tracing of NMDA and GABA-A Receptors in Rat Brain After Traumatic Brain Injury Using 18F-GE-179 and 18F-GE-194 Autoradiography. J Nucl Med 2016; 57:1442-7. [DOI: 10.2967/jnumed.115.167403] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 04/07/2016] [Indexed: 12/30/2022] Open
|
23
|
Klein PJ, Chomet M, Metaxas A, Christiaans JAM, Kooijman E, Schuit RC, Lammertsma AA, van Berckel BNM, Windhorst AD. Synthesis, radiolabeling and evaluation of novel amine guanidine derivatives as potential positron emission tomography tracers for the ion channel of the N-methyl-d-aspartate receptor. Eur J Med Chem 2016; 118:143-60. [PMID: 27128179 DOI: 10.1016/j.ejmech.2016.04.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 04/06/2016] [Accepted: 04/07/2016] [Indexed: 11/25/2022]
Abstract
The N-Methyl-d-Aspartate receptor (NMDAR) is involved in many neurological and psychiatric disorders including Alzheimer's disease and schizophrenia. The aim of this study was to develop a positron emission tomography (PET) ligand to assess the bio-availability of the NMDAR ion channel in vivo. A series of tri-N-substituted diarylguanidines was synthesized and their in vitro binding affinities for the NMDAR ion channel assessed in rat forebrain membrane fractions. Compounds 21, 23 and 26 were radiolabeled with either carbon-11 or fluorine-18 and ex vivo biodistribution and metabolite studies were performed in Wistar rats. Biodistribution studies showed high uptake especially in prefrontal cortex and lowest uptake in cerebellum. Pre-treatment with MK-801, however, did not decrease uptake of the radiolabeled ligands. In addition, all three ligands showed fast metabolism.
Collapse
Affiliation(s)
- Pieter J Klein
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam, The Netherlands.
| | - Marion Chomet
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam, The Netherlands
| | - Athanasios Metaxas
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam, The Netherlands
| | - Johannes A M Christiaans
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam, The Netherlands
| | - Esther Kooijman
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam, The Netherlands
| | - Robert C Schuit
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam, The Netherlands
| | - Adriaan A Lammertsma
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam, The Netherlands
| | - Bart N M van Berckel
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam, The Netherlands
| | - Albert D Windhorst
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam, The Netherlands
| |
Collapse
|
24
|
Naumiec GR, Jenko KJ, Zoghbi SS, Innis RB, Cai L, Pike VW. N'-3-(Trifluoromethyl)phenyl Derivatives of N-Aryl-N'-methylguanidines as Prospective PET Radioligands for the Open Channel of the N-Methyl-d-aspartate (NMDA) Receptor: Synthesis and Structure-Affinity Relationships. J Med Chem 2015; 58:9722-30. [PMID: 26588360 DOI: 10.1021/acs.jmedchem.5b01510] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
N-Methyl-d-aspartate (NMDA) receptor dysfunction has been linked to several neuropsychiatric disorders, including Alzheimer's disease, epilepsy, drug addiction, and schizophrenia. A radioligand that could be used with PET to image and quantify human brain NMDA receptors in the activated "open channel" state would be useful for research on such disorders and for the development of novel therapies. To date, no radioligands have shown well-validated efficacy for imaging NMDA receptors in human subjects. In order to discover improved radioligands for PET imaging, we explored structure-affinity relationships in N'-3-(trifluoromethyl)phenyl derivatives of N-aryl-N'-methylguanidines, seeking high affinity and moderate lipophilicity, plus necessary amenability for labeling with a positron-emitter, either carbon-11 or fluorine-18. Among a diverse set of 80 prepared N'-3-(trifluoromethyl)phenyl derivatives, four of these compounds (13, 19, 20, and 36) displayed desirable low nanomolar affinity for inhibition of [(3)H](+)-MK801 at the PCP binding site and are of interest for candidate PET radioligand development.
Collapse
Affiliation(s)
- Gregory R Naumiec
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health , Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892-1003, United States
| | - Kimberley J Jenko
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health , Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892-1003, United States
| | - Sami S Zoghbi
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health , Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892-1003, United States
| | - Robert B Innis
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health , Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892-1003, United States
| | - Lisheng Cai
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health , Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892-1003, United States
| | - Victor W Pike
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health , Building 10, Room B3 C346A, 10 Center Drive, Bethesda, Maryland 20892-1003, United States
| |
Collapse
|
25
|
Salabert AS, Fonta C, Fontan C, Adel D, Alonso M, Pestourie C, Belhadj-Tahar H, Tafani M, Payoux P. Radiolabeling of [18F]-fluoroethylnormemantine and initial in vivo evaluation of this innovative PET tracer for imaging the PCP sites of NMDA receptors. Nucl Med Biol 2015; 42:643-53. [PMID: 25963911 DOI: 10.1016/j.nucmedbio.2015.04.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 03/19/2015] [Accepted: 04/01/2015] [Indexed: 01/01/2023]
Abstract
INTRODUCTION The N-methyl-D-aspartate receptor (NMDAr) is an ionotropic receptor that mediates excitatory transmission. NMDAr overexcitation is thought to be involved in neurological and neuropsychiatric disorders such as Alzheimer disease and schizophrenia. We synthesized [(18)F]-fluoroethylnormemantine ([(18)F]-FNM), a memantine derivative that binds to phencyclidine (PCP) sites within the NMDA channel pore. These sites are primarily accessible when the channel is in the active and open state. METHODS Radiosynthesis was carried out using the Raytest® SynChrom R&D fluorination module. Affinity of this new compound was determined by competition assay. We ran a kinetic study in rats and computed a time-activity curve based on a volume-of-interest analysis, using CARIMAS® software. We performed an ex vivo autoradiography, exposing frozen rat brain sections to a phosphorscreen. Adjacent sections were used to detect NMDAr by immunohistochemistry with an anti-NR1 antibody. As a control of the specificity of our compound for NMDAr, we used a rat anesthetized with ketamine. Correlation analysis was performed with ImageJ software between signal of autoradiography and immunostaining. RESULTS Fluorination yield was 10.5% (end of synthesis), with a mean activity of 3145 MBq and a specific activity above 355 GBq/μmol. Affinity assessment allowed us to determine [(19)F]-FNM IC50 at 6.1 10(-6)M. [(18)F]-FMN concentration gradually increased in the brain, stabilizing at 40 minutes post injection. The brain-to-blood ratio was 6, and 0.4% of the injected dose was found in the brain. Combined ex vivo autoradiography and immunohistochemical staining demonstrated colocalization of NMDAr and [(18)F]-FNM (r=0.622, p<0.0001). The highest intensity was found in the cortex and cerebellum, and the lowest in white matter. A low and homogeneous signal corresponding to unspecific binding was observed when PCP sites were blocked with ketamine. CONCLUSIONS [(18)F]-FNM appears to be a promising tracer for imaging NMDAr activity for undertaking preclinical studies in perspective of clinical detection of neurological or neuropsychological disorders.
Collapse
Affiliation(s)
- Anne-Sophie Salabert
- Brain Imaging and Neurological Disability UMR 825, INSERM, F-31059 Toulouse, France; Brain imaging and neurological disability UMR 825, University of Toulouse, UPS, CHU Purpan, Place du Dr Baylac, F-31059 Toulouse Cedex 9, France; Radiopharmacy Department, University Hospital, Toulouse, France.
| | - Caroline Fonta
- Research Center for Brain and Cognition, University of Toulouse UPS, Toulouse, France; CerCo, CNRS, Toulouse, France
| | - Charlotte Fontan
- Brain Imaging and Neurological Disability UMR 825, INSERM, F-31059 Toulouse, France; Brain imaging and neurological disability UMR 825, University of Toulouse, UPS, CHU Purpan, Place du Dr Baylac, F-31059 Toulouse Cedex 9, France; Radiopharmacy Department, University Hospital, Toulouse, France
| | - Djilali Adel
- Brain Imaging and Neurological Disability UMR 825, INSERM, F-31059 Toulouse, France; Brain imaging and neurological disability UMR 825, University of Toulouse, UPS, CHU Purpan, Place du Dr Baylac, F-31059 Toulouse Cedex 9, France
| | - Mathieu Alonso
- Radiopharmacy Department, University Hospital, Toulouse, France
| | | | - Hafid Belhadj-Tahar
- Research and Expertise Group, French Association for the Promotion of Medical Research (AFPREMED), Toulouse, France
| | - Mathieu Tafani
- Brain Imaging and Neurological Disability UMR 825, INSERM, F-31059 Toulouse, France; Brain imaging and neurological disability UMR 825, University of Toulouse, UPS, CHU Purpan, Place du Dr Baylac, F-31059 Toulouse Cedex 9, France; Radiopharmacy Department, University Hospital, Toulouse, France
| | - Pierre Payoux
- Brain Imaging and Neurological Disability UMR 825, INSERM, F-31059 Toulouse, France; Brain imaging and neurological disability UMR 825, University of Toulouse, UPS, CHU Purpan, Place du Dr Baylac, F-31059 Toulouse Cedex 9, France; Nuclear Medicine Department, University Hospital, Toulouse, France
| |
Collapse
|
26
|
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.
Collapse
|
27
|
Kniess T, Laube M, Brust P, Steinbach J. 2-[18F]Fluoroethyl tosylate – a versatile tool for building18F-based radiotracers for positron emission tomography. MEDCHEMCOMM 2015. [DOI: 10.1039/c5md00303b] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The review highlights the role of 2-[18F]fluoroethyltosylate ([18F]FETs) in PET radiotracer design since it is a preferred labeling reagent according to its high reactivity to phenolic, amine, thiophenolic and carboxylic functions.
Collapse
Affiliation(s)
- Torsten Kniess
- Helmholtz-Zentrum Dresden-Rossendorf
- Institute of Radiopharmaceutical Cancer Research
- Dresden
- Germany
| | - Markus Laube
- Helmholtz-Zentrum Dresden-Rossendorf
- Institute of Radiopharmaceutical Cancer Research
- Dresden
- Germany
| | - Peter Brust
- Helmholtz-Zentrum Dresden-Rossendorf
- Institute of Radiopharmaceutical Cancer Research
- Dresden
- Germany
| | - Jörg Steinbach
- Helmholtz-Zentrum Dresden-Rossendorf
- Institute of Radiopharmaceutical Cancer Research
- Dresden
- Germany
| |
Collapse
|
28
|
Naumiec GR, Cai L, Pike VW. New N-aryl-N'-(3-(substituted)phenyl)-N'-methylguanidines as leads to potential PET radioligands for imaging the open NMDA receptor. Bioorg Med Chem Lett 2014; 25:225-8. [PMID: 25499436 DOI: 10.1016/j.bmcl.2014.11.066] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 11/21/2014] [Accepted: 11/24/2014] [Indexed: 12/28/2022]
Abstract
An expansive set of N-aryl-N'-(3-(substituted)phenyl)-N'-methylguanidines was prepared in a search for new leads to prospective PET ligands for imaging of the open channel of the N-methyl-d-aspartate (NMDA) receptor in vivo. The N-aryl rings and their substituents were varied, whereas the N-methyl group was maintained as a site for potential labeling with the positron-emitter, carbon-11 (t1/2=20.4min). At micromolar concentration, over half of the prepared compounds strongly inhibited the binding of [(3)H]TCP to its binding site in the open NMDA receptor in vitro. Four ligands displayed affinities that are similar or superior to those of the promising SPECT radioligand ([(123)I]CNS1261). The 3'-dimethylamino (19; Ki 36.7nM), 3'-trifluoromethyl (20; Ki 18.3nM) and 3'-methylthio (2; Ki 39.8nM) derivatives of N-1-naphthyl-N'-(phenyl)-N'-methylguanidine were identified as especially attractive leads for PET radioligand development.
Collapse
Affiliation(s)
- Gregory R Naumiec
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, MD 20892, United States
| | - Lisheng Cai
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, MD 20892, United States
| | - Victor W Pike
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, Bethesda, MD 20892, United States.
| |
Collapse
|
29
|
McGinnity CJ, Hammers A, Riaño Barros DA, Luthra SK, Jones PA, Trigg W, Micallef C, Symms MR, Brooks DJ, Koepp MJ, Duncan JS. Initial evaluation of 18F-GE-179, a putative PET Tracer for activated N-methyl D-aspartate receptors. J Nucl Med 2014; 55:423-30. [PMID: 24525206 DOI: 10.2967/jnumed.113.130641] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
UNLABELLED N-methyl D-aspartate (NMDA) ion channels play a key role in a wide range of physiologic (e.g., memory and learning tasks) and pathologic processes (e.g., excitotoxicity). To date, suitable PET markers of NMDA ion channel activity have not been available. (18)F-GE-179 is a novel radioligand that selectively binds to the open/active state of the NMDA receptor ion channel, displacing the binding of (3)H-tenocyclidine from the intrachannel binding site with an affinity of 2.4 nM. No significant binding was observed with 10 nM GE-179 at 60 other neuroreceptors, channels, or transporters. We describe the kinetic behavior of the radioligand in vivo in humans. METHODS Nine healthy participants (6 men, 3 women; median age, 37 y) each underwent a 90-min PET scan after an intravenous injection of (18)F-GE-179. Continuous arterial blood sampling over the first 15 min was followed by discrete blood sampling over the duration of the scan. Brain radioactivity (KBq/mL) was measured in summation images created from the attenuation- and motion-corrected dynamic images. Metabolite-corrected parent plasma input functions were generated. We assessed the abilities of 1-, 2-, and 3-compartment models to kinetically describe cerebral time-activity curves using 6 bilateral regions of interest. Parametric volume-of-distribution (V(T)) images were generated by voxelwise rank-shaping regularization of exponential spectral analysis (RS-ESA). RESULTS A 2-brain-compartment, 4-rate-constant model best described the radioligand's kinetics in normal gray matter of subjects at rest. At 30 min after injection, 37% of plasma radioactivity represented unmetabolized (18)F-GE-179. The highest mean levels of gray matter radioactivity were seen in the putamina and peaked at 7.5 min. A significant positive correlation was observed between K1 and V(T) (Spearman ρ = 0.398; P = 0.003). Between-subject coefficients of variation of V(T) ranged between 12% and 16%. Voxelwise RS-ESA yielded similar V(T)s and coefficients of variation. CONCLUSION (18)F-GE-179 exhibits high and rapid brain extraction, with a relatively homogeneous distribution in gray matter and acceptable between-subject variability. Despite its rapid peripheral metabolism, quantification of (18)F-GE-179 VT is feasible both within regions of interest and at the voxel level. The specificity of (18)F-GE-179 binding, however, requires further characterization with in vivo studies using activation and disease models.
Collapse
Affiliation(s)
- Colm J McGinnity
- Division of Brain Sciences, Department of Medicine, Imperial College London, London, United Kingdom
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Park C, Lee BS, Chi DY. High efficiency synthesis of F-18 fluoromethyl ethers: an attractive alternative for C-11 methyl groups in positron emission tomography radiopharmaceuticals. Org Lett 2013; 15:4346-9. [PMID: 23930998 DOI: 10.1021/ol401792n] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
A rapid and efficient method for the synthesis of O-fluoromethyl aliphatic and aromatic ethers is presented. This method is so mild that it can be used for the preparation of positron emission tomography (PET) radiopharmaceuticals bearing O-[(18)F]fluoromethyl groups.
Collapse
Affiliation(s)
- Chansoo Park
- Department of Chemistry, Sogang University, 35 Baekbeomro Mapogu, Seoul 121-742, Korea
| | | | | |
Collapse
|
31
|
Sączewski F, Balewski Ł. Biological activities of guanidine compounds, 2008 - 2012 update. Expert Opin Ther Pat 2013; 23:965-95. [PMID: 23617396 DOI: 10.1517/13543776.2013.788645] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Compounds incorporating guanidine moiety have found many practical applications in diverse areas of chemistry, such as nucleophilic organocatalysis, anion recognition and coordination chemistry. Moreover, guanidine functional group is found in natural products, pharmaceuticals and cosmetic ingredients produced by synthetic methods. Thus, knowledge of their biological activities and therapeutic uses is of utmost importance for researchers involved in drug discovery processes. AREAS COVERED In this review the authors highlight the continued development and therapeutic applications of newly synthesized guanidine-containing compounds including small peptides and peptidomimetics incorporating arginine. The review presents patents and patent applications filed in the years 2008 - 2012 with emphasis placed on new mechanisms of pharmacological action of guanidine derivatives. EXPERT OPINION While guanidines are often thought of as strong organic bases and compounds hydrophilic in nature, over the last 4 years there has been an enormous increase in discovery of new promising lead structures with guanidine core, suitable for development of potential drugs acting at central nervous system, anti-inflammatory agents, anti-diabetic and chemotherapeutic agents as well as cosmetics.
Collapse
Affiliation(s)
- Franciszek Sączewski
- Medical University of Gdańsk, Department of Chemical Technology of Drugs, Al. Gen. Hallera 107, 80-416 Gdańsk, Poland.
| | | |
Collapse
|
32
|
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]
|
33
|
Pérez-Medina C, Patel N, Robson M, Badar A, Lythgoe MF, Årstad E. Evaluation of a 125I-labelled benzazepinone derived voltage-gated sodium channel blocker for imaging with SPECT. Org Biomol Chem 2012; 10:9474-80. [PMID: 23117159 DOI: 10.1039/c2ob26695d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Voltage-gated sodium channels (VGSCs) are a family of transmembrane proteins that mediate fast neurotransmission, and are integral to sustain physiological conditions and higher cognitive functions. Imaging of VGSCs in vivo holds promise as a tool to elucidate operational functions in the brain and to aid the treatment of a wide range of neurological diseases. To assess the suitability of 1-benzazepin-2-one derived VGSC blockers for imaging, we have prepared a (125)I-labelled analogue of BNZA and evaluated the tracer in vivo. In an automated patch-clamp assay, a diastereomeric mixture of the non-radioactive compound blocked the Na(v)1.2 and Na(v)1.7 VGSC isoforms with IC(50) values of 4.1 ± 1.5 μM and 0.25 ± 0.07 μM, respectively. [(3)H]BTX displacement studies revealed a three-fold difference in affinity between the two diastereomers. Iodo-destannylation of a tin precursor with iodine-125 afforded the two diastereomerically pure tracers, which were used to assess binding to VGSCs in vivo by comparing their tissue distributions in mice. Whilst the results point to a lack of VGSC binding in vivo, SPECT imaging revealed highly localized uptake in the interscapular region, an area typically associated with brown adipose tissue, which in addition to high metabolic stability of the iodinated tracer, demonstrate the potential of 1-benzazepin-2-ones for in vivo imaging.
Collapse
Affiliation(s)
- Carlos Pérez-Medina
- Department of Chemistry and Institute of Nuclear Medicine, UCL, 235 Euston Road (T-5), NW1 2BU London, United Kingdom
| | | | | | | | | | | |
Collapse
|
34
|
Koller M, Urwyler S. Novel N-methyl-D-aspartate receptor antagonists: a review of compounds patented since 2006. Expert Opin Ther Pat 2010; 20:1683-702. [PMID: 21054234 DOI: 10.1517/13543776.2010.533656] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
IMPORTANCE OF THE FIELD The NMDA receptor is a complex ligand gated, voltage-dependent ion channel. It has been a drug target for > 25 years for neurological and psychiatric indications. Whereas the initial optimism to turn preclinically active compounds rapidly into drugs for human use was dampened, new insights into cellular receptor localization, role of subunits and receptor operation have kept the interest alive to modulate this receptor for therapeutic intervention. AREAS COVERED IN THIS REVIEW The article describes the NMDA receptor antagonists patented since 2006. Also included are novel NMDA receptor ligands potentially useful for positron emission tomography imaging. WHAT THE READER WILL GAIN The first section summarizes the current status of NMDA receptor pharmacology. This serves as a base for the next sections discussing the patented compounds with respect to their mode of action, potency and, in some cases, drugability. TAKE HOME MESSAGE The most important recent strategies aiming for inhibition of NMDA receptor-mediated neurotransmission avoid for safety reasons full receptor blockade but allow a low degree of normal receptor function. Approaches pursued by the latest patents comprise blocking the channel with compounds of low affinity, antagonizing receptor activity by highly potent NR2B ligands, partial agonism at the glutamate or glycine-binding site and improvement of pharmacokinetic properties of well established, safe antagonists by deuteration.
Collapse
Affiliation(s)
- Manuel Koller
- Novartis Institutes for BioMedical Research, Global Discovery Chemistry, Basel, Switzerland.
| | | |
Collapse
|