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He Y, Delparente A, Jie CVML, Keller C, Humm R, Heer D, Collin L, Schibli R, Gobbi L, Grether U, Mu L. Preclinical Evaluation of the Reversible Monoacylglycerol Lipase PET Tracer (R)-[ 11C]YH132: Application in Drug Development and Neurodegenerative Diseases. Chembiochem 2024; 25:e202300819. [PMID: 38441502 DOI: 10.1002/cbic.202300819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 01/12/2024] [Indexed: 04/05/2024]
Abstract
Monoacylglycerol lipase (MAGL) plays a crucial role in the degradation of 2-arachidonoylglycerol (2-AG), one of the major endocannabinoids in the brain. Inhibiting MAGL could lead to increased levels of 2-AG, which showed beneficial effects on pain management, anxiety, inflammation, and neuroprotection. In the current study, we report the characterization of an enantiomerically pure (R)-[11C]YH132 as a novel MAGL PET tracer. It demonstrates an improved pharmacokinetic profile compared to its racemate. High in vitro MAGL specificity of (R)-[11C]YH132 was confirmed by autoradiography studies using mouse and rat brain sections. In vivo, (R)-[11C]YH132 displayed a high brain penetration, and high specificity and selectivity toward MAGL by dynamic PET imaging using MAGL knockout and wild-type mice. Pretreatment with a MAGL drug candidate revealed a dose-dependent reduction of (R)-[11C]YH132 accumulation in WT mouse brains. This result validates its utility as a PET probe to assist drug development. Moreover, its potential application in neurodegenerative diseases was explored by in vitro autoradiography using brain sections from animal models of Alzheimer's disease and Parkinson's disease.
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Affiliation(s)
- Yingfang He
- Institute of Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 4, CH-8093, Zurich, Switzerland
- Present address: Institute of Radiation Medicine, Fudan University, Xietu Road 2094, Shanghai, 200032, China
| | - Aro Delparente
- Institute of Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 4, CH-8093, Zurich, Switzerland
| | - Caitlin V M L Jie
- Institute of Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 4, CH-8093, Zurich, Switzerland
| | - Claudia Keller
- Institute of Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 4, CH-8093, Zurich, Switzerland
| | - Roland Humm
- Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, CH-4070, Basel, Switzerland
| | - Dominik Heer
- Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, CH-4070, Basel, Switzerland
| | - Ludovic Collin
- Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, CH-4070, Basel, Switzerland
| | - Roger Schibli
- Institute of Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 4, CH-8093, Zurich, Switzerland
| | - Luca Gobbi
- Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, CH-4070, Basel, Switzerland
| | - Uwe Grether
- Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, CH-4070, Basel, Switzerland
| | - Linjing Mu
- Institute of Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 4, CH-8093, Zurich, Switzerland
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Vidas-Guscic N, van Rijswijk J, Van Audekerke J, Jeurissen B, Nnah I, Tang H, Muñoz-Sanjuan I, Pustina D, Cachope R, Van der Linden A, Bertoglio D, Verhoye M. Diffusion MRI marks progressive alterations in fiber integrity in the zQ175DN mouse model of Huntington's disease. Neurobiol Dis 2024; 193:106438. [PMID: 38365045 DOI: 10.1016/j.nbd.2024.106438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 01/24/2024] [Accepted: 02/13/2024] [Indexed: 02/18/2024] Open
Abstract
Huntington's disease (HD) is a progressive neurodegenerative disease affecting motor and cognitive abilities. Multiple studies have found white matter anomalies in HD-affected humans and animal models of HD. The identification of sensitive white-matter-based biomarkers in HD animal models will be important in understanding disease mechanisms and testing the efficacy of therapeutic interventions. Here we investigated the progression of white matter deficits in the knock-in zQ175DN heterozygous (HET) mouse model of HD at 3, 6 and 11 months of age (M), reflecting different states of phenotypic progression. We compared findings from traditional diffusion tensor imaging (DTI) and advanced fixel-based analysis (FBA) diffusion metrics for their sensitivity in detecting white matter anomalies in the striatum, motor cortex, and segments of the corpus callosum. FBA metrics revealed progressive and widespread reductions of fiber cross-section and fiber density in myelinated bundles of HET mice. The corpus callosum genu was the most affected structure in HET mice at 6 and 11 M based on the DTI and FBA metrics, while the striatum showed the earliest progressive differences starting at 3 M based on the FBA metrics. Overall, FBA metrics detected earlier and more prominent alterations in myelinated fiber bundles compared to the DTI metrics. Luxol fast blue staining showed no loss in myelin density, indicating that diffusion anomalies could not be explained by myelin reduction but diffusion anomalies in HET mice were accompanied by increased levels of neurofilament light chain protein at 11 M. Altogether, our findings reveal progressive alterations in myelinated fiber bundles that can be measured using diffusion MRI, representing a candidate noninvasive imaging biomarker to study phenotype progression and the efficacy of therapeutic interventions in zQ175DN mice. Moreover, our study exposed higher sensitivity of FBA than DTI metrics, suggesting a potential benefit of adopting these advanced metrics in other contexts, including biomarker development in humans.
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Affiliation(s)
- Nicholas Vidas-Guscic
- Bio-Imaging Lab, University of Antwerp, Antwerp, Belgium; μNeuro Center for Excellence, University of Antwerp, Antwerp, Belgium.
| | - Joëlle van Rijswijk
- Bio-Imaging Lab, University of Antwerp, Antwerp, Belgium; μNeuro Center for Excellence, University of Antwerp, Antwerp, Belgium
| | - Johan Van Audekerke
- Bio-Imaging Lab, University of Antwerp, Antwerp, Belgium; μNeuro Center for Excellence, University of Antwerp, Antwerp, Belgium
| | - Ben Jeurissen
- μNeuro Center for Excellence, University of Antwerp, Antwerp, Belgium; Vision Lab, University of Antwerp, Antwerp, Belgium; Lab for Equilibrium Investigations and Aerospace, University of Antwerp, Antwerp, Belgium
| | - Israel Nnah
- Charles River Laboratories, Shrewsbury, MA, United states
| | - Haiying Tang
- CHDI Management, Inc., the company that manages the scientific activities of CHDI Foundation, Inc., Princeton, NJ, United States
| | - Ignacio Muñoz-Sanjuan
- CHDI Management, Inc., the company that manages the scientific activities of CHDI Foundation, Inc., Princeton, NJ, United States
| | - Dorian Pustina
- CHDI Management, Inc., the company that manages the scientific activities of CHDI Foundation, Inc., Princeton, NJ, United States
| | - Roger Cachope
- CHDI Management, Inc., the company that manages the scientific activities of CHDI Foundation, Inc., Princeton, NJ, United States
| | - Annemie Van der Linden
- Bio-Imaging Lab, University of Antwerp, Antwerp, Belgium; μNeuro Center for Excellence, University of Antwerp, Antwerp, Belgium
| | - Daniele Bertoglio
- Bio-Imaging Lab, University of Antwerp, Antwerp, Belgium; μNeuro Center for Excellence, University of Antwerp, Antwerp, Belgium
| | - Marleen Verhoye
- Bio-Imaging Lab, University of Antwerp, Antwerp, Belgium; μNeuro Center for Excellence, University of Antwerp, Antwerp, Belgium
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Cools R, Kerkhofs K, Leitao RCF, Bormans G. Preclinical Evaluation of Novel PET Probes for Dementia. Semin Nucl Med 2023; 53:599-629. [PMID: 37149435 DOI: 10.1053/j.semnuclmed.2023.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 03/24/2023] [Indexed: 05/08/2023]
Abstract
The development of novel PET imaging agents that selectively bind specific dementia-related targets can contribute significantly to accurate, differential and early diagnosis of dementia causing diseases and support the development of therapeutic agents. Consequently, in recent years there has been a growing body of literature describing the development and evaluation of potential new promising PET tracers for dementia. This review article provides a comprehensive overview of novel dementia PET probes under development, classified by their target, and pinpoints their preclinical evaluation pathway, typically involving in silico, in vitro and ex/in vivo evaluation. Specific target-associated challenges and pitfalls, requiring extensive and well-designed preclinical experimental evaluation assays to enable successful clinical translation and avoid shortcomings observed for previously developed 'well-established' dementia PET tracers are highlighted in this review.
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Affiliation(s)
- Romy Cools
- Laboratory for Radiopharmaceutical Research, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | - Kobe Kerkhofs
- Laboratory for Radiopharmaceutical Research, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium; NURA, Belgian Nuclear Research Centre (SCK CEN), Mol, Belgium
| | - Renan C F Leitao
- Laboratory for Radiopharmaceutical Research, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | - Guy Bormans
- Laboratory for Radiopharmaceutical Research, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium.
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Budgett RF, Bakker G, Sergeev E, Bennett KA, Bradley SJ. Targeting the Type 5 Metabotropic Glutamate Receptor: A Potential Therapeutic Strategy for Neurodegenerative Diseases? Front Pharmacol 2022; 13:893422. [PMID: 35645791 PMCID: PMC9130574 DOI: 10.3389/fphar.2022.893422] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 04/18/2022] [Indexed: 01/13/2023] Open
Abstract
The type 5 metabotropic glutamate receptor, mGlu5, has been proposed as a potential therapeutic target for the treatment of several neurodegenerative diseases. In preclinical neurodegenerative disease models, novel allosteric modulators have been shown to improve cognitive performance and reduce disease-related pathology. A common pathological hallmark of neurodegenerative diseases is a chronic neuroinflammatory response, involving glial cells such as astrocytes and microglia. Since mGlu5 is expressed in astrocytes, targeting this receptor could provide a potential mechanism by which neuroinflammatory processes in neurodegenerative disease may be modulated. This review will discuss current evidence that highlights the potential of mGlu5 allosteric modulators to treat neurodegenerative diseases, including Alzheimer’s disease, Huntington’s disease, Parkinson’s disease, and amyotrophic lateral sclerosis. Furthermore, this review will explore the role of mGlu5 in neuroinflammatory responses, and the potential for this G protein-coupled receptor to modulate neuroinflammation.
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Affiliation(s)
- Rebecca F Budgett
- The Centre for Translational Pharmacology, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | | | | | | | - Sophie J Bradley
- The Centre for Translational Pharmacology, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom.,Sosei Heptares, Cambridge, United Kingdom
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Callahan JW, Wokosin DL, Bevan MD. Dysregulation of the Basal Ganglia Indirect Pathway in Early Symptomatic Q175 Huntington's Disease Mice. J Neurosci 2022; 42:2080-2102. [PMID: 35058372 PMCID: PMC8916764 DOI: 10.1523/jneurosci.0782-21.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 12/16/2021] [Accepted: 01/11/2022] [Indexed: 11/21/2022] Open
Abstract
The debilitating psychomotor symptoms of Huntington's disease (HD) are linked partly to degeneration of the basal ganglia indirect pathway. At early symptomatic stages, before major cell loss, indirect pathway neurons exhibit numerous cellular and synaptic changes in HD and its models. However, the impact of these alterations on circuit activity remains poorly understood. To address this gap, optogenetic- and reporter-guided electrophysiological interrogation was used in early symptomatic male and female Q175 HD mice. D2 dopamine receptor-expressing striatal projection neurons (D2-SPNs) were hypoactive during synchronous cortical slow-wave activity, consistent with known reductions in dendritic excitability and cortical input strength. Downstream prototypic parvalbumin-expressing external globus pallidus (PV+ GPe) neurons discharged at 2-3 times their normal rate, even during periods of D2-SPN inactivity, arguing that defective striatopallidal inhibition was not the only cause of their hyperactivity. Indeed, PV+ GPe neurons also exhibited abnormally elevated autonomous firing ex vivo Optogenetic inhibition of PV+ GPe neurons in vivo partially and fully ameliorated the abnormal hypoactivity of postsynaptic subthalamic nucleus (STN) and putative PV- GPe neurons, respectively. In contrast to STN neurons whose autonomous firing is impaired in HD mice, putative PV- GPe neuron activity was unaffected ex vivo, implying that excessive inhibition was responsible for their hypoactivity in vivo Together with previous studies, these data demonstrate that (1) indirect pathway nuclei are dysregulated in Q175 mice through changes in presynaptic activity and/or intrinsic cellular and synaptic properties; and (2) prototypic PV+ GPe neuron hyperactivity and excessive target inhibition are prominent features of early HD pathophysiology.SIGNIFICANCE STATEMENT The early symptoms of Huntington's disease (HD) are linked to degenerative changes in the action-suppressing indirect pathway of the basal ganglia. Consistent with this linkage, the intrinsic properties of cells in this pathway exhibit complex alterations in HD and its models. However, the impact of these changes on activity is poorly understood. Using electrophysiological and optogenetic approaches, we demonstrate that the indirect pathway is highly dysregulated in early symptomatic HD mice through changes in upstream activity and/or intrinsic properties. Furthermore, we reveal that hyperactivity of external globus pallidus neurons and excessive inhibition of their targets are key features of early HD pathophysiology. Together, these findings could help to inform the development and targeting of viral-based, gene therapeutic approaches for HD.
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Affiliation(s)
- Joshua W Callahan
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
| | - David L Wokosin
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
| | - Mark D Bevan
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
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Bertoglio D, Bard J, Hessmann M, Liu L, Gärtner A, De Lombaerde S, Huscher B, Zajicek F, Miranda A, Peters F, Herrmann F, Schaertl S, Vasilkovska T, Brown CJ, Johnson PD, Prime ME, Mills MR, Van der Linden A, Mrzljak L, Khetarpal V, Wang Y, Marchionini DM, Skinbjerg M, Verhaeghe J, Dominguez C, Staelens S, Munoz-Sanjuan I. Development of a ligand for in vivo imaging of mutant huntingtin in Huntington's disease. Sci Transl Med 2022; 14:eabm3682. [PMID: 35108063 DOI: 10.1126/scitranslmed.abm3682] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Huntington's disease (HD) is a dominantly inherited neurodegenerative disorder caused by a CAG trinucleotide expansion in the huntingtin (HTT) gene that encodes the pathologic mutant HTT (mHTT) protein with an expanded polyglutamine (polyQ) tract. Whereas several therapeutic programs targeting mHTT expression have advanced to clinical evaluation, methods to visualize mHTT protein species in the living brain are lacking. Here, we demonstrate the development and characterization of a positron emission tomography (PET) imaging radioligand with high affinity and selectivity for mHTT aggregates. This small molecule radiolabeled with 11C ([11C]CHDI-180R) allowed noninvasive monitoring of mHTT pathology in the brain and could track region- and time-dependent suppression of mHTT in response to therapeutic interventions targeting mHTT expression in a rodent model. We further showed that in these animals, therapeutic agents that lowered mHTT in the striatum had a functional restorative effect that could be measured by preservation of striatal imaging markers, enabling a translational path to assess the functional effect of mHTT lowering.
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Affiliation(s)
- Daniele Bertoglio
- Molecular Imaging Center Antwerp (MICA), University of Antwerp, Wilrijk 2610, Belgium
| | - Jonathan Bard
- CHDI Management/CHDI Foundation, Los Angeles, CA 90045, USA
| | | | - Longbin Liu
- CHDI Management/CHDI Foundation, Los Angeles, CA 90045, USA
| | | | - Stef De Lombaerde
- Molecular Imaging Center Antwerp (MICA), University of Antwerp, Wilrijk 2610, Belgium.,Department of Nuclear Medicine, Antwerp University Hospital, Edegem 2650, Belgium
| | | | - Franziska Zajicek
- Molecular Imaging Center Antwerp (MICA), University of Antwerp, Wilrijk 2610, Belgium
| | - Alan Miranda
- Molecular Imaging Center Antwerp (MICA), University of Antwerp, Wilrijk 2610, Belgium
| | | | | | | | | | | | | | | | | | | | | | | | - Yuchuan Wang
- CHDI Management/CHDI Foundation, Los Angeles, CA 90045, USA
| | | | | | - Jeroen Verhaeghe
- Molecular Imaging Center Antwerp (MICA), University of Antwerp, Wilrijk 2610, Belgium
| | | | - Steven Staelens
- Molecular Imaging Center Antwerp (MICA), University of Antwerp, Wilrijk 2610, Belgium
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Bertoglio D, Verhaeghe J, Wyffels L, Miranda A, Stroobants S, Mrzljak L, Dominguez C, Skinbjerg M, Bard J, Liu L, Munoz-Sanjuan I, Staelens S. Synaptic vesicle glycoprotein 2A is affected in the CNS of Huntington's Disease mice and post-mortem human HD brain. J Nucl Med 2021; 63:942-947. [PMID: 34531262 DOI: 10.2967/jnumed.121.262709] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 08/26/2021] [Indexed: 11/16/2022] Open
Abstract
Synaptic dysfunction is a primary mechanism underlying Huntington's Disease (HD) progression. This study investigated changes in synaptic vesicle glycoprotein 2A (SV2A) density by means of 11C-UCB-J microPET imaging in the central nervous system (CNS) of HD mice. METHODS: Dynamic 11C-UCB-J microPET imaging was performed at clinically relevant disease stages (at 3, 7, 10, and 16 months, M) in the heterozygous knock-in Q175DN mouse model of HD and WT littermates (n = 16-18/genotype and time point). Cerebral 11C-UCB-J analyses were performed to assess genotypic differences during pre-symptomatic (3M) and symptomatic (7-16M) disease stages. 11C-UCB-J binding in the spinal cord was quantified at 16M. 3H-UCB-J autoradiography and SV2A immunofluorescence were performed post-mortem in mouse and human brain tissue. RESULTS: 11C-UCB-J binding was declined in symptomatic heterozygous mice compared to WT littermates in parallel with disease progression (7M: p<0.01, 16M: p<0.0001). Specific 11C-UCB-J binding was detectable in the spinal cord, with symptomatic heterozygous mice displaying a significant reduction (p<0.0001). 3H-UCB-J autoradiography and SV2A immunofluorescence corroborated the in vivo measurements demonstrating lowered SV2A in heterozygous mice (p<0.05). Finally, preliminary analysis of SV2A in post-mortem human brain suggested lower SV2A in HD gene carrier compared to nondemented control. CONCLUSION: 11C-UCB-J PET detects SV2A deficits during symptomatic disease in heterozygous mice in both brain and spinal cord, offering a novel marker of synaptic integrity widely distributed in CNS. Upon clinical application, 11C-UCB-J PET imaging yields promise for SV2A measurement in patients with HD during disease progression and following disease-modifying therapeutic strategies.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Longbin Liu
- CHDI Management/CHDI Foundation, United States
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Goud NS, Bhattacharya A, Joshi RK, Nagaraj C, Bharath RD, Kumar P. Carbon-11: Radiochemistry and Target-Based PET Molecular Imaging Applications in Oncology, Cardiology, and Neurology. J Med Chem 2021; 64:1223-1259. [PMID: 33499603 DOI: 10.1021/acs.jmedchem.0c01053] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The positron emission tomography (PET) molecular imaging technique has gained its universal value as a remarkable tool for medical diagnosis and biomedical research. Carbon-11 is one of the promising radiotracers that can report target-specific information related to its pharmacology and physiology to understand the disease status. Currently, many of the available carbon-11 (t1/2 = 20.4 min) PET radiotracers are heterocyclic derivatives that have been synthesized using carbon-11 inserted different functional groups obtained from primary and secondary carbon-11 precursors. A spectrum of carbon-11 PET radiotracers has been developed against many of the upregulated and emerging targets for the diagnosis, prognosis, prediction, and therapy in the fields of oncology, cardiology, and neurology. This review focuses on the carbon-11 radiochemistry and various target-specific PET molecular imaging agents used in tumor, heart, brain, and neuroinflammatory disease imaging along with its associated pathology.
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Affiliation(s)
- Nerella Sridhar Goud
- Department of Neuroimaging and Interventional Radiology (NIIR), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru 560 029, India
| | - Ahana Bhattacharya
- Department of Neuroimaging and Interventional Radiology (NIIR), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru 560 029, India
| | - Raman Kumar Joshi
- Department of Neuroimaging and Interventional Radiology (NIIR), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru 560 029, India
| | - Chandana Nagaraj
- Department of Neuroimaging and Interventional Radiology (NIIR), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru 560 029, India
| | - Rose Dawn Bharath
- Department of Neuroimaging and Interventional Radiology (NIIR), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru 560 029, India
| | - Pardeep Kumar
- Department of Neuroimaging and Interventional Radiology (NIIR), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru 560 029, India
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Abstract
This article presents an overview of imaging agents for PET that have been applied for research and diagnostic purposes in patients affected by dementia. Classified by the target which the agents visualize, seven groups of tracers can be distinguished, namely radiopharmaceuticals for: (1) Misfolded proteins (ß-amyloid, tau, α-synuclein), (2) Neuroinflammation (overexpression of translocator protein), (3) Elements of the cholinergic system, (4) Elements of monoamine neurotransmitter systems, (5) Synaptic density, (6) Cerebral energy metabolism (glucose transport/ hexokinase), and (7) Various other proteins. This last category contains proteins involved in mechanisms underlying neuroinflammation or cognitive impairment, which may also be potential therapeutic targets. Many receptors belong to this category: AMPA, cannabinoid, colony stimulating factor 1, metabotropic glutamate receptor 1 and 5 (mGluR1, mGluR5), opioid (kappa, mu), purinergic (P2X7, P2Y12), sigma-1, sigma-2, receptor for advanced glycation endproducts, and triggering receptor expressed on myeloid cells-1, besides several enzymes: cyclooxygenase-1 and 2 (COX-1, COX-2), phosphodiesterase-5 and 10 (PDE5, PDE10), and tropomyosin receptor kinase. Significant advances in neuroimaging have been made in the last 15 years. The use of 2-[18F]-fluoro-2-deoxy-D-glucose (FDG) for quantification of regional cerebral glucose metabolism is well-established. Three tracers for ß-amyloid plaques have been approved by the Food and Drug Administration and European Medicines Agency. Several tracers for tau neurofibrillary tangles are already applied in clinical research. Since many novel agents are in the preclinical or experimental stage of development, further advances in nuclear medicine imaging can be expected in the near future. PET studies with established tracers and tracers for novel targets may result in early diagnosis and better classification of neurodegenerative disorders and in accurate monitoring of therapy trials which involve these targets. PET data have prognostic value and may be used to assess the response of the human brain to interventions, or to select the appropriate treatment strategy for an individual patient.
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Affiliation(s)
- Aren van Waarde
- University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, Groningen, the Netherlands.
| | - Sofia Marcolini
- University of Groningen, University Medical Center Groningen, Department of Neurology, Groningen, the Netherlands
| | - Peter Paul de Deyn
- University of Groningen, University Medical Center Groningen, Department of Neurology, Groningen, the Netherlands; University of Antwerp, Born-Bunge Institute, Neurochemistry and Behavior, Campus Drie Eiken, Wilrijk, Belgium
| | - Rudi A J O Dierckx
- University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, Groningen, the Netherlands; Ghent University, Ghent, Belgium
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10
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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] [What about the content of this article? (0)] [Affiliation(s)] [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.
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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.)
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Cybulska K, Perk L, Booij J, Laverman P, Rijpkema M. Huntington's Disease: A Review of the Known PET Imaging Biomarkers and Targeting Radiotracers. Molecules 2020; 25:molecules25030482. [PMID: 31979301 PMCID: PMC7038198 DOI: 10.3390/molecules25030482] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 01/14/2020] [Accepted: 01/15/2020] [Indexed: 12/19/2022] Open
Abstract
Huntington’s disease (HD) is a fatal neurodegenerative disease caused by a CAG expansion mutation in the huntingtin gene. As a result, intranuclear inclusions of mutant huntingtin protein are formed, which damage striatal medium spiny neurons (MSNs). A review of Positron Emission Tomography (PET) studies relating to HD was performed, including clinical and preclinical data. PET is a powerful tool for visualisation of the HD pathology by non-invasive imaging of specific radiopharmaceuticals, which provide a detailed molecular snapshot of complex mechanistic pathways within the brain. Nowadays, radiochemists are equipped with an impressive arsenal of radioligands to accurately recognise particular receptors of interest. These include key biomarkers of HD: adenosine, cannabinoid, dopaminergic and glutamateric receptors, microglial activation, phosphodiesterase 10 A and synaptic vesicle proteins. This review aims to provide a radiochemical picture of the recent developments in the field of HD PET, with significant attention devoted to radiosynthetic routes towards the tracers relevant to this disease.
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Affiliation(s)
- Klaudia Cybulska
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Geert Grooteplein-Zuid 10, 6525 EZ Nijmegen, The Netherlands; (J.B.); (P.L.); (M.R.)
- Radboud Translational Medicine B.V., Radboud University Medical Center, Geert Grooteplein 21 (route 142), 6525 EZ Nijmegen, The Netherlands;
- Correspondence:
| | - Lars Perk
- Radboud Translational Medicine B.V., Radboud University Medical Center, Geert Grooteplein 21 (route 142), 6525 EZ Nijmegen, The Netherlands;
| | - Jan Booij
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Geert Grooteplein-Zuid 10, 6525 EZ Nijmegen, The Netherlands; (J.B.); (P.L.); (M.R.)
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Centers, Academic Medical Center, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Peter Laverman
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Geert Grooteplein-Zuid 10, 6525 EZ Nijmegen, The Netherlands; (J.B.); (P.L.); (M.R.)
| | - Mark Rijpkema
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Geert Grooteplein-Zuid 10, 6525 EZ Nijmegen, The Netherlands; (J.B.); (P.L.); (M.R.)
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12
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Bertoglio D, Verhaeghe J, Korat Š, Miranda A, Cybulska K, Wyffels L, Stroobants S, Mrzljak L, Dominguez C, Skinbjerg M, Liu L, Munoz-Sanjuan I, Staelens S. Elevated Type 1 Metabotropic Glutamate Receptor Availability in a Mouse Model of Huntington's Disease: a Longitudinal PET Study. Mol Neurobiol 2020; 57:2038-2047. [PMID: 31912442 PMCID: PMC7118044 DOI: 10.1007/s12035-019-01866-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 12/22/2019] [Indexed: 12/11/2022]
Abstract
Impairment of group I metabotropic glutamate receptors (mGluRs) results in altered glutamate signalling, which is associated with several neurological disorders including Huntington’s Disease (HD), an autosomal neurodegenerative disease. In this study, we assessed in vivo pathological changes in mGluR1 availability in the Q175DN mouse model of HD using longitudinal positron emission tomography (PET) imaging with the radioligand [11C]ITDM. Ninety-minute dynamic PET imaging scans were performed in 22 heterozygous (HET) Q175DN mice and 22 wild-type (WT) littermates longitudinally at 6, 12, and 16 months of age. Analyses of regional volume of distribution with an image-derived input function (VT (IDIF)) and voxel-wise parametric VT (IDIF) maps were performed to assess differences between genotypes. Post-mortem evaluation at 16 months was done to support in vivo findings. [11C]ITDM VT (IDIF) quantification revealed higher mGluR1 availability in the brain of HET mice compared to WT littermates (e.g. cerebellum: + 15.0%, + 17.9%, and + 17.6% at 6, 12, and 16 months, respectively; p < 0.001). In addition, an age-related decline in [11C]ITDM binding independent of genotype was observed between 6 and 12 months. Voxel-wise analysis of parametric maps and post-mortem quantifications confirmed the elevated mGluR1 availability in HET mice compared to WT littermates. In conclusion, in vivo measurement of mGluR1 availability using longitudinal [11C]ITDM PET imaging demonstrated higher [11C]ITDM binding in extra-striatal brain regions during the course of disease in the Q175DN mouse model.
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Affiliation(s)
- Daniele Bertoglio
- Molecular Imaging Center Antwerp (MICA), University of Antwerp, Wilrijk, Belgium
| | - Jeroen Verhaeghe
- Molecular Imaging Center Antwerp (MICA), University of Antwerp, Wilrijk, Belgium
| | - Špela Korat
- Molecular Imaging Center Antwerp (MICA), University of Antwerp, Wilrijk, Belgium
- Department of Nuclear Medicine, Antwerp University Hospital, Edegem, Belgium
| | - Alan Miranda
- Molecular Imaging Center Antwerp (MICA), University of Antwerp, Wilrijk, Belgium
| | - Klaudia Cybulska
- Molecular Imaging Center Antwerp (MICA), University of Antwerp, Wilrijk, Belgium
- Department of Nuclear Medicine, Antwerp University Hospital, Edegem, Belgium
| | - Leonie Wyffels
- Molecular Imaging Center Antwerp (MICA), University of Antwerp, Wilrijk, Belgium
- Department of Nuclear Medicine, Antwerp University Hospital, Edegem, Belgium
| | - Sigrid Stroobants
- Molecular Imaging Center Antwerp (MICA), University of Antwerp, Wilrijk, Belgium
- Department of Nuclear Medicine, Antwerp University Hospital, Edegem, Belgium
| | | | | | | | - Longbin Liu
- CHDI Management/CHDI Foundation, Los Angeles, CA, USA
| | | | - Steven Staelens
- Molecular Imaging Center Antwerp (MICA), University of Antwerp, Wilrijk, Belgium.
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13
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Crabbé M, Dirkx N, Casteels C, Laere KV. Excitotoxic neurodegeneration is associated with a focal decrease in metabotropic glutamate receptor type 5 availability: an in vivo PET imaging study. Sci Rep 2019; 9:12916. [PMID: 31501497 PMCID: PMC6733799 DOI: 10.1038/s41598-019-49356-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Accepted: 08/23/2019] [Indexed: 11/09/2022] Open
Abstract
Metabotropic glutamate receptors (mGluRs) have been proposed as promising therapeutic targets to correct the dysregulated glutamate signaling, associated with neurodegenerative pathologies. Of all mGluR subtypes, especially mGluR5 acts as a modulator of glutamate-induced excitotoxicity. To study the behavior of mGluR5 following localized excitotoxicity, we utilised a pharmacological model that portrays exacerbated neuronal glutamate release, mediated by the endogenous excitotoxin quinolinic acid (QA). Using longitudinal positron emission tomography (PET) with [18F]FPEB, we investigated cerebral changes in mGluR5 following striatal QA-lesioning. Behavioral tests were executed to monitor motor and cognitive performance. Decreased mGluR5 binding potential (BPND) was found in the affected striatum and globus pallidus of QA-lesioned rats at week 3, and further decreased at week 7, as compared to sham-injected controls. mGluR5 availability in the ipsilateral nucleus accumbens was significantly decreased at 7 weeks post-injection. QA rats performed significantly worse on motor coordination and balance compared to control rats. Correlation analysis indicated a positive correlation between striatal mGluR5 BPND and rotarod performance whereas print width of the unaffected forepaws showed a positive relation with mGluR5 BPND in the contralateral motor cortex. Together, our results suggest decreased mGluR5 availability to be related to excitotoxin-induced neurodegeneration and symptomatology although late stage effects do indicate possible cortical mGluR5-mediated effects on motor behavior.
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Affiliation(s)
- Melissa Crabbé
- Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, KU Leuven and University Hospitals Leuven, Leuven, Belgium. .,MoSAIC - Molecular Small Animal Imaging Centre, KU Leuven, Leuven, Belgium.
| | - Nina Dirkx
- Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, KU Leuven and University Hospitals Leuven, Leuven, Belgium.,MoSAIC - Molecular Small Animal Imaging Centre, KU Leuven, Leuven, Belgium
| | - Cindy Casteels
- Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, KU Leuven and University Hospitals Leuven, Leuven, Belgium.,MoSAIC - Molecular Small Animal Imaging Centre, KU Leuven, Leuven, Belgium
| | - Koen Van Laere
- Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, KU Leuven and University Hospitals Leuven, Leuven, Belgium.,MoSAIC - Molecular Small Animal Imaging Centre, KU Leuven, Leuven, Belgium
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