1
|
Bai P, Bagdasarian FA, Xu Y, Wang Y, Wang Y, Gomm A, Zhou Y, Wu R, Wey HY, Tanzi RE, Zhang C, Lan Y, Wang C. Molecular Imaging of Alzheimer's Disease-Related Sigma-1 Receptor in the Brain via a Novel Ru-Mediated Aromatic 18F-deoxyfluorination Probe. J Med Chem 2024; 67:6207-6217. [PMID: 38607332 DOI: 10.1021/acs.jmedchem.3c02178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/13/2024]
Abstract
Sigma-1 receptor (σ1R) is an intracellular protein implicated in a spectrum of neurodegenerative conditions, notably Alzheimer's disease (AD). Positron emission tomography (PET) imaging of brain σ1R could provide a powerful tool for better understanding the underlying pathomechanism of σ1R in AD. In this study, we successfully developed a 18F-labeled σ1R radiotracer [18F]CNY-05 via an innovative ruthenium (Ru)-mediated 18F-deoxyfluorination method. [18F]CNY-05 exhibited preferable brain uptake, high specific binding, and slightly reversible pharmacokinetics within the PET scanning time window. PET imaging of [18F]CNY-05 in nonhuman primates (NHP) indicated brain permeability, metabolic stability, and safety. Moreover, autoradiography and PET studies of [18F]CNY-05 in the AD mouse model found a significantly decreased brain uptake compared to that in wild-type mice. Collectively, we have provided a novel 18F-radiolabeled σ1R PET probe, which enables visualizing brain σ1R in health and neurological diseases.
Collapse
Affiliation(s)
- Ping Bai
- Department of Respiratory and Critical Care Medicine, Targeted Tracer Research and Development Laboratory, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
- Institute of Respiratory Health, Targeted Tracer Research and Development Laboratory, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
- Precision Medicine Center, Precision Medicine Key Laboratory of Sichuan Province, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
- The Research Units of West China, Chinese Academy of Medical Sciences, West China Hospital, Chengdu, Sichuan 610041, China
- State Key Laboratory of Respiratory Health and Multimorbidity, West China Hospital, Chengdu, Sichuan 610041, China
| | - Frederick A Bagdasarian
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, United States
| | - Yulong Xu
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, United States
| | - Yanli Wang
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, United States
| | - Yongle Wang
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, United States
| | - Ashley Gomm
- Genetics and Aging Research Unit, McCance Center for Brain Health, MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, 114 16th Street, Charlestown, Massachusetts 02129, United States
| | - Yanting Zhou
- Department of Respiratory and Critical Care Medicine, Targeted Tracer Research and Development Laboratory, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
- Institute of Respiratory Health, Targeted Tracer Research and Development Laboratory, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
- Precision Medicine Center, Precision Medicine Key Laboratory of Sichuan Province, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
- The Research Units of West China, Chinese Academy of Medical Sciences, West China Hospital, Chengdu, Sichuan 610041, China
- State Key Laboratory of Respiratory Health and Multimorbidity, West China Hospital, Chengdu, Sichuan 610041, China
| | - Rui Wu
- Department of Respiratory and Critical Care Medicine, Targeted Tracer Research and Development Laboratory, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
- Institute of Respiratory Health, Targeted Tracer Research and Development Laboratory, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
- Precision Medicine Center, Precision Medicine Key Laboratory of Sichuan Province, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
- The Research Units of West China, Chinese Academy of Medical Sciences, West China Hospital, Chengdu, Sichuan 610041, China
- State Key Laboratory of Respiratory Health and Multimorbidity, West China Hospital, Chengdu, Sichuan 610041, China
| | - Hsiao-Ying Wey
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, United States
| | - Rudolph E Tanzi
- Genetics and Aging Research Unit, McCance Center for Brain Health, MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, 114 16th Street, Charlestown, Massachusetts 02129, United States
| | - Can Zhang
- Genetics and Aging Research Unit, McCance Center for Brain Health, MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, 114 16th Street, Charlestown, Massachusetts 02129, United States
| | - Yu Lan
- Department of Pharmacy, Renmin Hospital of Wuhan University, Wuhan, Hubei 430060, China
| | - Changning Wang
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, United States
| |
Collapse
|
2
|
Wang T, Jia H. The Sigma Receptors in Alzheimer's Disease: New Potential Targets for Diagnosis and Therapy. Int J Mol Sci 2023; 24:12025. [PMID: 37569401 PMCID: PMC10418732 DOI: 10.3390/ijms241512025] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 07/14/2023] [Accepted: 07/16/2023] [Indexed: 08/13/2023] Open
Abstract
Sigma (σ) receptors are a class of unique proteins with two subtypes: the sigma-1 (σ1) receptor which is situated at the mitochondria-associated endoplasmic reticulum (ER) membrane (MAM), and the sigma-2 (σ2) receptor, located in the ER-resident membrane. Increasing evidence indicates the involvement of both σ1 and σ2 receptors in the pathogenesis of Alzheimer's disease (AD), and thus these receptors represent two potentially effective biomarkers for emerging AD therapies. The availability of optimal radioligands for positron emission tomography (PET) neuroimaging of the σ1 and σ2 receptors in humans will provide tools to monitor AD progression and treatment outcomes. In this review, we first summarize the significance of both receptors in the pathophysiology of AD and highlight AD therapeutic strategies related to the σ1 and σ2 receptors. We then survey the potential PET radioligands, with an emphasis on the requirements of optimal radioligands for imaging the σ1 or σ2 receptors in humans. Finally, we discuss current challenges in the development of PET radioligands for the σ1 or σ2 receptors, and the opportunities for neuroimaging to elucidate the σ1 and σ2 receptors as novel biomarkers for early AD diagnosis, and for monitoring of disease progression and AD drug efficacy.
Collapse
Affiliation(s)
- Tao Wang
- Key Laboratory of Radiopharmaceuticals (Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China;
- Department of Nuclear Medicine, Xinqiao Hospital, Army Medical University, Chongqing 400037, China
| | - Hongmei Jia
- Key Laboratory of Radiopharmaceuticals (Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China;
| |
Collapse
|
3
|
Cai L, Liow JS, Morse CL, Telu S, Davies R, Manly LS, Zoghbi SS, Chin FT, Innis RB, Pike VW. Candidate 3-benzazepine-1-ol type GluN2B receptor radioligands ( 11C-NR2B-Me enantiomers) have high binding in cerebellum but not to σ1 receptors. EJNMMI Res 2023; 13:28. [PMID: 37017827 PMCID: PMC10076467 DOI: 10.1186/s13550-023-00975-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 03/12/2023] [Indexed: 04/06/2023] Open
Abstract
INTRODUCTION We recently reported 11C-NR2B-SMe ([S-methyl-11C](R,S)-7-thiomethoxy-3-(4-(4-methyl-phenyl)butyl)-2,3,4,5-tetrahydro-1H-benzo[d]azepin-1-ol) and its enantiomers as candidate radioligands for imaging the GluN2B subunit within rat N-methyl-D-aspartate receptors. However, these radioligands gave unexpectedly high and displaceable binding in rat cerebellum, possibly due to cross-reactivity with sigma-1 (σ1) receptors. This study investigated 11C-labeled enantiomers of a close analogue (7-methoxy-3-(4-(p-tolyl)butyl)-2,3,4,5-tetrahydro-1H-benzo[d]azepin-1-ol; NR2B-Me) of 11C-NR2B-SMe as new candidate GluN2B radioligands. PET was used to evaluate these radioligands in rats and to assess potential cross-reactivity to σ1 receptors. METHODS NR2B-Me was assayed for binding affinity and selectivity to GluN2B in vitro. 11C-NR2B-Me and its enantiomers were prepared by Pd-mediated treatment of boronic ester precursors with 11C-iodomethane. Brain PET scans were conducted after radioligand intravenous injection into rats. Various ligands for GluN2B receptors or σ1 receptors were administered at set doses in pre-blocking or displacement experiments to assess their impact on imaging data. 18F-FTC146 and enantiomers of 11C-NR2B-SMe were used for comparison. Radiometabolites from brain and plasma were measured ex vivo and in vitro. RESULTS NR2B-Me enantiomers showed high GluN2B affinity and selectivity in vitro. 11C-NR2B-Me enantiomers gave high early whole rat brain uptake of radioactivity, including high uptake in cerebellum, followed by slower decline. Radioactivity in brain at 30 min ex vivo was virtually all unchanged radioligand. Only less lipophilic radiometabolites appeared in plasma. When 11C-(R)-NR2B-Me was used, three high-affinity GluN2B ligands-NR2B-SMe, Ro25-6981, and CO101,244-showed increasing pre-block of whole brain radioactivity retention with increasing dose. Two σ1 receptor antagonists, FTC146 and BD1407, were ineffective pre-blocking agents. Together, these results strongly resemble those obtained with 11C-NR2B-SMe enantiomers, except that 11C-NR2B-Me enantiomers showed faster reversibility of binding. When 18F-FTC146 was used as a radioligand, FTC146 and BD1407 showed strong pre-blocking effects whereas GluN2B ligands showed only weak blocking effects. CONCLUSION 11C-NR2B-Me enantiomers showed specific binding to GluN2B receptors in rat brain in vivo. High unexpected specific binding in cerebellum was not due to σ1 receptors. Additional investigation is needed to identify the source of the high specific binding.
Collapse
Affiliation(s)
- Lisheng Cai
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, 10 Center Dr, Bldg 10, Room B3 C346, Bethesda, MD, 20892, USA.
| | - Jeih-San Liow
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, 10 Center Dr, Bldg 10, Room B3 C346, Bethesda, MD, 20892, USA
| | - Cheryl L Morse
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, 10 Center Dr, Bldg 10, Room B3 C346, Bethesda, MD, 20892, USA
| | - Sanjay Telu
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, 10 Center Dr, Bldg 10, Room B3 C346, Bethesda, MD, 20892, USA
| | - Riley Davies
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, 10 Center Dr, Bldg 10, Room B3 C346, Bethesda, MD, 20892, USA
| | - Lester S Manly
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, 10 Center Dr, Bldg 10, Room B3 C346, Bethesda, MD, 20892, USA
| | - Sami S Zoghbi
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, 10 Center Dr, Bldg 10, Room B3 C346, Bethesda, MD, 20892, USA
| | - Frederick T Chin
- Molecular Imaging Program at Stanford, Department of Radiology, Stanford University, 1201 Welch Road, Rm. PS049, Stanford, CA, 94305-584, USA
| | - Robert B Innis
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, 10 Center Dr, Bldg 10, Room B3 C346, Bethesda, MD, 20892, USA
| | - Victor W Pike
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, 10 Center Dr, Bldg 10, Room B3 C346, Bethesda, MD, 20892, USA
| |
Collapse
|
4
|
Wang YM, Xia CY, Jia HM, He J, Lian WW, Yan Y, Wang WP, Zhang WK, Xu JK. Sigma-1 receptor: A potential target for the development of antidepressants. Neurochem Int 2022; 159:105390. [PMID: 35810915 DOI: 10.1016/j.neuint.2022.105390] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 06/10/2022] [Accepted: 07/05/2022] [Indexed: 10/17/2022]
Abstract
Though a great many of studies on the development of antidepressants for the therapy of major depression disorder (MDD) and the development of antidepressants have been carried out, there still lacks an efficient approach in clinical practice. The involvement of Sigma-1 receptor in the pathological process of MDD has been verified. In this review, recent research focusing on the role of Sigma-1 receptor in the etiology of MDD were summarized. Preclinical studies and clinical trials have found that stress induce the variation of Sigma-1 receptor in the blood, brain and heart. Dysfunction and absence of Sigma-1 receptor result in depressive-like behaviors in rodent animals. Agonists of Sigma-1 receptor show not only antidepressant-like activities but also therapeutical effects in complications of depression. The mechanisms underlying antidepressant-like effects of Sigma-1 receptor may include suppressing neuroinflammation, regulating neurotransmitters, ameliorating brain-derived neurotrophic factor and N-Methyl-D-Aspartate receptor, and alleviating the endoplasmic reticulum stress and mitochondria damage during stress. Therefore, Sigma-1 receptor represents a potential target for antidepressants development.
Collapse
Affiliation(s)
- Yu-Ming Wang
- School of Life Sciences & School of Chinese Medicine Sciences, Beijing University of Chinese Medicine, Beijing, 100029, PR China; Institute of Clinical Medical Sciences & Department of Pharmacy, China-Japan Friendship Hospital, Beijing, 100029, PR China
| | - Cong-Yuan Xia
- Institute of Clinical Medical Sciences & Department of Pharmacy, China-Japan Friendship Hospital, Beijing, 100029, PR China
| | - Hong-Mei Jia
- Key Laboratory of Radiopharmaceuticals (Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, PR China
| | - Jun He
- Institute of Clinical Medical Sciences & Department of Pharmacy, China-Japan Friendship Hospital, Beijing, 100029, PR China
| | - Wen-Wen Lian
- Institute of Clinical Medical Sciences & Department of Pharmacy, China-Japan Friendship Hospital, Beijing, 100029, PR China
| | - Yu Yan
- Institute of Clinical Medical Sciences & Department of Pharmacy, China-Japan Friendship Hospital, Beijing, 100029, PR China
| | - Wen-Ping Wang
- Institute of Clinical Medical Sciences & Department of Pharmacy, China-Japan Friendship Hospital, Beijing, 100029, PR China
| | - Wei-Ku Zhang
- Institute of Clinical Medical Sciences & Department of Pharmacy, China-Japan Friendship Hospital, Beijing, 100029, PR China.
| | - Jie-Kun Xu
- School of Life Sciences & School of Chinese Medicine Sciences, Beijing University of Chinese Medicine, Beijing, 100029, PR China.
| |
Collapse
|
5
|
Venkataraman AV, Mansur A, Rizzo G, Bishop C, Lewis Y, Kocagoncu E, Lingford-Hughes A, Huiban M, Passchier J, Rowe JB, Tsukada H, Brooks DJ, Martarello L, Comley RA, Chen L, Schwarz AJ, Hargreaves R, Gunn RN, Rabiner EA, Matthews PM. Widespread cell stress and mitochondrial dysfunction occur in patients with early Alzheimer's disease. Sci Transl Med 2022; 14:eabk1051. [PMID: 35976998 DOI: 10.1126/scitranslmed.abk1051] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Cell stress and impaired oxidative phosphorylation are central to mechanisms of synaptic loss and neurodegeneration in the cellular pathology of Alzheimer's disease (AD). In this study, we quantified the in vivo expression of the endoplasmic reticulum stress marker, sigma 1 receptor (S1R), using [11C]SA4503 positron emission tomography (PET), the mitochondrial complex I (MC1) with [18F]BCPP-EF, and the presynaptic vesicular protein SV2A with [11C]UCB-J in 12 patients with early AD and in 16 cognitively normal controls. We integrated these molecular measures with assessments of regional brain volumes and cerebral blood flow (CBF) measured with magnetic resonance imaging arterial spin labeling. Eight patients with AD were followed longitudinally to estimate the rate of change of the physiological and structural pathology markers with disease progression. The patients showed widespread increases in S1R (≤ 27%) and regional reduction in MC1 (≥ -28%) and SV2A (≥ -25%) radioligand binding, brain volume (≥ -23%), and CBF (≥ -26%). [18F]BCPP-EF PET MC1 binding (≥ -12%) and brain volumes (≥ -5%) showed progressive reductions over 12 to 18 months, suggesting that they both could be used as pharmacodynamic indicators in early-stage therapeutics trials. Associations of reduced MC1 and SV2A and increased S1R radioligand binding with reduced cognitive performance in AD, although exploratory, suggested a loss of metabolic functional reserve with disease. Our study thus provides in vivo evidence for widespread, clinically relevant cellular stress and bioenergetic abnormalities in early AD.
Collapse
Affiliation(s)
- Ashwin V Venkataraman
- Department of Brain Sciences, Imperial College London, London W12 0NN, UK.,UK Dementia Research Institute at Imperial College London, London W12 0NN, UK
| | | | - Gaia Rizzo
- Department of Brain Sciences, Imperial College London, London W12 0NN, UK.,Invicro LLC, London W12 0NN, UK
| | | | | | | | | | | | | | | | - Hideo Tsukada
- Hamamatsu Photonics, Hamakita, Hamamatsu, Shizuoka 4348601, Japan
| | - David J Brooks
- University of Newcastle upon Tyne, Newcastle NE2 4HH, UK.,Department of Clinical Medicine, Aarhus University, Aarhus 8200, Denmark
| | | | | | | | | | | | - Roger N Gunn
- Department of Brain Sciences, Imperial College London, London W12 0NN, UK.,Invicro LLC, London W12 0NN, UK
| | - Eugenii A Rabiner
- Invicro LLC, London W12 0NN, UK.,King's College London, London SE5 8AF, UK
| | - Paul M Matthews
- Department of Brain Sciences, Imperial College London, London W12 0NN, UK.,UK Dementia Research Institute at Imperial College London, London W12 0NN, UK
| |
Collapse
|
6
|
Rabiner EA, Smith K, Bennett C, Rizzo G, Lewis Y, Mundin G, Dooner H, Oksche A. Pharmacokinetics and brain σ1 receptor occupancy of MR309, a selective σ1 receptor antagonist. Br J Clin Pharmacol 2022; 88:1644-1654. [PMID: 34156715 DOI: 10.1111/bcp.14952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 06/02/2021] [Accepted: 06/09/2021] [Indexed: 11/30/2022] Open
Abstract
AIMS Preclinical studies of MR309, a selective sigma-1 receptor (σ1R) antagonist, support a potential role in treating neuropathic pain. We report 2 studies that provide insight into the pharmacokinetics (PK) and brain σ1R binding of MR309. METHODS Steady-state PK of MR309 (400 mg once daily and 200 mg twice-daily [BID] for 10 days; EudraCT 2015-001818-99 [PK study]) and the relationship between MR309 plasma exposure and brain σ1R occupancy (EudraCT 2017-000670-11 [positron emission tomography study]) were investigated in healthy volunteers. Positron emission tomography using the σ1R ligand [11 C]SA4503 was conducted at baseline, and 2 and 8 hours after a single dose of MR309 (200-800 mg). The relationship between brain σ1R occupancy and MR309 exposure was explored using data-driven model fitting. RESULTS MR309 was well tolerated, brain σ1R occupancy ranged between 30.5 and 74.9% following single-dose MR309 (n = 7). MR309 BID provided a plasma PK profile with less fluctuation than once daily dosing (n = 16). MR309 200 mg BID yielded average steady state plasma concentrations between 2000 and 4000 ng/mL in the PK study, which corresponded to an estimated brain σ1R occupancy of 59-74%. CONCLUSION MR309 200 mg BID dose was below the 75% σ1R occupancy threshold expected to elicit maximal antinociceptive effect as observed in neuropathic pain models. Further investigations of MR309 for neuropathic pain will require higher brain σ1R occupancy, and establish the optimal dose by elucidating the clinical impact of a broad range of brain σ1R occupancy across different neuropathic pain indications.
Collapse
Affiliation(s)
- Eugenii A Rabiner
- Invicro(former Imanova Ltd), A Konica Minolta Company, London, UK
- Centre for Neuroimaging Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College, London, UK
| | | | | | - Gaia Rizzo
- Invicro(former Imanova Ltd), A Konica Minolta Company, London, UK
- Division of Brain Sciences, Department of Medicine, Imperial College, London, UK
| | - Yvonne Lewis
- Invicro(former Imanova Ltd), A Konica Minolta Company, London, UK
| | | | | | - Alexander Oksche
- Mundipharma Research Limited, Cambridge, UK
- Institut für medizinische und pharmazeutische Prüfungsfragen, Mainz, Germany
- Rudolf-Buchheim Institute of Pharmacology, Giessen, Germany
| |
Collapse
|
7
|
Highly Specific Sigma Receptor Ligands Exhibit Anti-Viral Properties in SARS-CoV-2 Infected Cells. Pathogens 2021; 10:pathogens10111514. [PMID: 34832669 PMCID: PMC8620039 DOI: 10.3390/pathogens10111514] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 11/10/2021] [Accepted: 11/17/2021] [Indexed: 12/23/2022] Open
Abstract
(1) Background: There is a strong need for prevention and treatment strategies for COVID-19 that are not impacted by SARS-CoV-2 mutations emerging in variants of concern. After virus infection, host ER resident sigma receptors form direct interactions with non-structural SARS-CoV-2 proteins present in the replication complex. (2) Methods: In this work, highly specific sigma receptor ligands were investigated for their ability to inhibit both SARS-CoV-2 genome replication and virus induced cellular toxicity. This study found antiviral activity associated with agonism of the sigma-1 receptor (e.g., SA4503), ligation of the sigma-2 receptor (e.g., CM398), and a combination of the two pathways (e.g., AZ66). (3) Results: Intermolecular contacts between these ligands and sigma receptors were identified by structural modeling. (4) Conclusions: Sigma receptor ligands and drugs with off-target sigma receptor binding characteristics were effective at inhibiting SARS-CoV-2 infection in primate and human cells, representing a potential therapeutic avenue for COVID-19 prevention and treatment.
Collapse
|
8
|
Liang Q, Joshi S, Liu H, Yu Y, Zhao H, Benzinger TLS, Perlmutter JS, Tu Z. In vitro characterization of [ 3H]VAT in cells, animal and human brain tissues for vesicular acetylcholine transporter. Eur J Pharmacol 2021; 911:174556. [PMID: 34627806 PMCID: PMC8605764 DOI: 10.1016/j.ejphar.2021.174556] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 09/02/2021] [Accepted: 09/03/2021] [Indexed: 11/23/2022]
Abstract
Vesicular acetylcholine transporter plays a crucial role in the cholinergic system, and its alterations is implicated in several neurodegenerative disorders. We recently developed a PET imaging tracer [18F]VAT to target VAChT in vivo with high affinity and selectivity. Here we report in vitro characterization of [3H]VAT, a tritiated counterpart of [18F]VAT. Using human VAChT-rich cell membrane extracts, a saturated binding curve was obtained for [3H]VAT with Kd = 6.5 nM and Bmax = 22.89 pmol/mg protein. In the [3H]VAT competition-binding assay with a panel of CNS ligands, binding inhibition of [3H]VAT was observed using VAChT ligands, the Ki values ranged from 5.41 to 33.3 nM. No inhibition was detected using a panel of other CNS ligands. In vitro [3H]VAT autoradiography of rat brain sections showed strong signals in the striatum, moderate to high signals in vermis, thalamus, cortex, and hippocampus, and weak signals in cerebellum. Strong [3H]VAT ARG signals were also observed from striatal sections of normal nonhuman primates and human brains. Competitive ARG study with human striatal sections demonstrated strong ARG signals of [3H]VAT in caudate and putamen were blocked significantly by either VAChT ligand TZ659 or (-)-vesamicol, but not by the σ1 receptor ligand Yun-122. ARG study also indicated that signal in the striatal sections from PSP human brains was lower than normal human brains. These data provide solid evidence supporting [18F]VAT as a suitable PET radiotracer for quantitative assessment of VAChT levels in vivo.
Collapse
Affiliation(s)
- Qianwa Liang
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Sumit Joshi
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Hui Liu
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Yanbo Yu
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Haiyang Zhao
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Tammie L S Benzinger
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA; Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Joel S Perlmutter
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA; Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, 63110, USA; Department of Neurology, Program in Occupational Therapy, Program in Physical Therapy, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Zhude Tu
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA.
| |
Collapse
|
9
|
Takamura Y, Kakuta H. In Vivo Receptor Visualization and Evaluation of Receptor Occupancy with Positron Emission Tomography. J Med Chem 2021; 64:5226-5251. [PMID: 33905258 DOI: 10.1021/acs.jmedchem.0c01714] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Positron emission tomography (PET) is useful for noninvasive in vivo visualization of disease-related receptors, for evaluation of receptor occupancy to determine an appropriate drug dosage, and for proof-of-concept of drug candidates in translational research. For these purposes, the specificity of the PET tracer for the target receptor is critical. Here, we review work in this area, focusing on the chemical structures of reported PET tracers, their Ki/Kd values, and the physical properties relevant to target receptor selectivity. Among these physical properties, such as cLogP, cLogD, molecular weight, topological polar surface area, number of hydrogen bond donors, and pKa, we focus especially on LogD and LogP as important physical properties that can be easily compared across a range of studies. We discuss the success of PET tracers in evaluating receptor occupancy and consider likely future developments in the field.
Collapse
Affiliation(s)
- Yuta Takamura
- Division of Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1-1-1, Tsushima-naka, Kita-ku, Okayama 700-8530, Japan
| | - Hiroki Kakuta
- Division of Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1-1-1, Tsushima-naka, Kita-ku, Okayama 700-8530, Japan
| |
Collapse
|
10
|
Agha H, McCurdy CR. In vitro and in vivo sigma 1 receptor imaging studies in different disease states. RSC Med Chem 2021; 12:154-177. [PMID: 34046607 PMCID: PMC8127618 DOI: 10.1039/d0md00186d] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 09/02/2020] [Indexed: 12/11/2022] Open
Abstract
The sigma receptor system has been classified into two distinct subtypes, sigma 1 (σ1R) and sigma 2 (σ2R). Sigma 1 receptors (σ1Rs) are involved in many neurodegenerative diseases and different central nervous system disorders such as Alzheimer's disease, Parkinson's disease, schizophrenia, and drug addiction, and pain. This makes them attractive targets for developing radioligands as tools to gain a better understanding of disease pathophysiology and clinical diagnosis. Over the years, several σ1R radioligands have been developed to image the changes in σ1R distribution and density providing insights into their role in disease development. Moreover, the involvement of both σ1Rs and σ2Rs with cancer make these ligands, especially those that are σ2R selective, great tools for imaging different types of tumors. This review will discuss the principles of molecular imaging using PET and SPECT, known σ1R radioligands and their applications for labelling σ1Rs under different disease conditions. Furthermore, this review will highlight σ1R radioligands that have demonstrated considerable potential as biomarkers, and an opportunity to fulfill the ultimate goal of better healthcare outcomes and improving human health.
Collapse
Affiliation(s)
- Hebaalla Agha
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida Gainesville FL 32610 USA +(352) 273 7705 +1 (352) 294 8691
| | - Christopher R McCurdy
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida Gainesville FL 32610 USA +(352) 273 7705 +1 (352) 294 8691
- UF Translational Drug Development Core, University of Florida Gainesville FL 32610 USA
| |
Collapse
|
11
|
Shigeno T, Kozaka T, Kitamura Y, Ogawa K, Taki J, Kinuya S, Shiba K. In vitro and in vivo evaluation of [ 125/123I]-2-[4-(2-iodophenyl)piperidino]cyclopentanol([ 125/123I]-OI5V) as a potential sigma-1 receptor ligand for SPECT. Ann Nucl Med 2021; 35:167-175. [PMID: 33417152 DOI: 10.1007/s12149-020-01552-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 10/28/2020] [Indexed: 11/26/2022]
Abstract
INTRODUCTION We investigated the characteristics of radio-iodinated 2-[4-(2-iodophenyl)piperidino]cyclopentanol (OI5V) as a single photon emission computed tomography (SPECT) ligand for mapping sigma-1 receptor (σ-1R), which plays an important role in stress remission in many organs. METHODS OI5V was synthesized from o-bromobenzaldehyde in three steps. OI5V was evaluated for its affinity to VAChT, σ-1 and σ-2 receptor by in vitro competitive binding assays using rat tissues and radioligands, [3H]vesamicol, ( +)-[3H]pentazocine and [3H]DTG, respectively. [125/123I]OI5V was prepared from o-trimethylstannyl-cyclopentanevesamicol (OT5V) by the iododestannylation reaction under no-carrier-added conditions. In vivo biodistribution study of [125I]OI5V in blood, brain regions and major organs of rats was performed at 2, 10, 30 and 60 min post-injection. In vivo blocking study and ex vivo autoradiography were performed to assess the binding selectivity of [125I]OI5V for σ-1 receptor. SPECT-CT imaging study was performed using [123I]OI5V. RESULTS OI5V demonstrated high selective binding affinity for σ-1R in vitro. In the biodistribution study, the blood-brain barrier (BBB) permeability of [125I]OI5V was high and the accumulation of [125I]OI5V in the rat cortex at 2 min post-injection exceeded 2.00%ID/g. In the in vivo blocking study, the accumulation of [125I]OI5V in the brain was significantly blocked by co-administration of 0.5 μmol of SA4503 and 1.0 μmol of pentazocine. Ex vivo autoradiography revealed that the regional brain accumulation of [125I]OI5V was similar to σ-1R-rich regions of the rat brain. SPECT images of [123I]OI5V in the rat brain reflected the distribution of sigma receptors in the brain. CONCLUSIONS This study confirmed that [125/123I]OI5V selectively binds σ-1R in the rat brain in vivo. [123I]OI5V was suggested to be useful as a σ-1R ligand for SPECT.
Collapse
Affiliation(s)
- Taiki Shigeno
- Division of Tracer Kinetics, Advanced Science Research Center, Kanazawa, Ishikawa, Japan
| | - Takashi Kozaka
- Division of Tracer Kinetics, Advanced Science Research Center, Kanazawa, Ishikawa, Japan
- Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa , Ishikawa, Japan
| | - Yoji Kitamura
- Division of Tracer Kinetics, Advanced Science Research Center, Kanazawa, Ishikawa, Japan
- Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa , Ishikawa, Japan
| | - Kazuma Ogawa
- Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa , Ishikawa, Japan
| | - Junichi Taki
- Department of Nuclear Medicine, Kanazawa University Hospital, 13-1 Takara-machi, Kanazawa, Ishikawa, 920-8640, Japan
| | - Seigo Kinuya
- Division of Tracer Kinetics, Advanced Science Research Center, Kanazawa, Ishikawa, Japan
- Department of Nuclear Medicine, Kanazawa University Hospital, 13-1 Takara-machi, Kanazawa, Ishikawa, 920-8640, Japan
| | - Kazuhiro Shiba
- Division of Tracer Kinetics, Advanced Science Research Center, Kanazawa, Ishikawa, Japan.
- Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa , Ishikawa, Japan.
| |
Collapse
|
12
|
Lepelletier FX, Vandesquille M, Asselin MC, Prenant C, Robinson AC, Mann DMA, Green M, Barnett E, Banister SD, Mottinelli M, Mesangeau C, McCurdy CR, Fricke IB, Jacobs AH, Kassiou M, Boutin H. Evaluation of 18F-IAM6067 as a sigma-1 receptor PET tracer for neurodegeneration in vivo in rodents and in human tissue. Theranostics 2020; 10:7938-7955. [PMID: 32724451 PMCID: PMC7381740 DOI: 10.7150/thno.47585] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 06/06/2020] [Indexed: 01/30/2023] Open
Abstract
The sigma 1 receptor (S1R) is widely expressed in the CNS and is mainly located on the endoplasmic reticulum. The S1R is involved in the regulation of many neurotransmission systems and, indirectly, in neurodegenerative diseases. The S1R may therefore represent an interesting neuronal biomarker in neurodegenerative diseases such as Parkinson's (PD) or Alzheimer's diseases (AD). Here we present the characterisation of the S1R-specific 18F-labelled tracer 18F-IAM6067 in two animal models and in human brain tissue. Methods: Wistar rats were used for PET-CT imaging (60 min dynamic acquisition) and metabolite analysis (1, 2, 5, 10, 20, 60 min post-injection). To verify in vivo selectivity, haloperidol, BD1047 (S1R ligand), CM398 (S2R ligand) and SB206553 (5HT2B/C antagonist) were administrated for pre-saturation studies. Excitotoxic lesions induced by intra-striatal injection of AMPA were also imaged by 18F-IAM6067 PET-CT to test the sensitivity of the methods in a well-established model of neuronal loss. Tracer brain uptake was also verified by autoradiography in rats and in a mouse model of PD (intrastriatal 6-hydroxydopamine (6-OHDA) unilateral lesion). Finally, human cortical binding was investigated by autoradiography in three groups of subjects (control subjects with Braak ≤2, and AD patients, Braak >2 & ≤4 and Braak >4 stages). Results: We demonstrate that despite rapid peripheral metabolism of 18F-IAM6067, radiolabelled metabolites were hardly detected in brain samples. Brain uptake of 18F-IAM6067 showed differences in S1R anatomical distribution, namely from high to low uptake: pons-raphe, thalamus medio-dorsal, substantia nigra, hypothalamus, cerebellum, cortical areas and striatum. Pre-saturation studies showed 79-90% blockade of the binding in all areas of the brain indicated above except with the 5HT2B/C antagonist SB206553 and S2R ligand CM398 which induced no significant blockade, indicating good specificity of 18F-IAM6067 for S1Rs. No difference between ipsi- and contralateral sides of the brain in the mouse model of PD was detected. AMPA lesion induced a significant 69% decrease in 18F-IAM6067 uptake in the globus pallidus matching the neuronal loss as measured by NeuN, but only a trend to decrease (-16%) in the caudate putamen despite a significant 91% decrease in neuronal count. Moreover, no difference in the human cortical binding was shown between AD groups and controls. Conclusion: This work shows that 18F-IAM6067 is a specific and selective S1R radiotracer. The absence or small changes in S1R detected here in animal models and human tissue warrants further investigations and suggests that S1R might not be the anticipated ideal biomarker for neuronal loss in neurodegenerative diseases such as AD and PD.
Collapse
Affiliation(s)
- François-Xavier Lepelletier
- Faculty of Biology, Medicine and Health, School of Biological Sciences, Division of Neuroscience and Experimental Psychology, University of Manchester, Manchester, United Kingdom
- Wolfson Molecular Imaging Centre, University of Manchester, Manchester, United Kingdom
| | - Matthias Vandesquille
- Faculty of Biology, Medicine and Health, School of Biological Sciences, Division of Neuroscience and Experimental Psychology, University of Manchester, Manchester, United Kingdom
- Wolfson Molecular Imaging Centre, University of Manchester, Manchester, United Kingdom
| | - Marie-Claude Asselin
- Wolfson Molecular Imaging Centre, University of Manchester, Manchester, United Kingdom
- Faculty of Biology, Medicine and Health, School of Health Sciences, Division of Informatics, Imaging and Data Sciences, University of Manchester, Manchester, United Kingdom
| | - Christian Prenant
- Wolfson Molecular Imaging Centre, University of Manchester, Manchester, United Kingdom
| | - Andrew C Robinson
- Salford Royal NHS Foundation Trust, Department of Clinical & Cognitive Neurosciences, Clinical Sciences Building, Salford, United Kingdom
| | - David M A Mann
- Salford Royal NHS Foundation Trust, Department of Clinical & Cognitive Neurosciences, Clinical Sciences Building, Salford, United Kingdom
| | - Michael Green
- Wolfson Molecular Imaging Centre, University of Manchester, Manchester, United Kingdom
- Faculty of Biology, Medicine and Health, School of Health Sciences, Division of Informatics, Imaging and Data Sciences, University of Manchester, Manchester, United Kingdom
| | - Elizabeth Barnett
- Wolfson Molecular Imaging Centre, University of Manchester, Manchester, United Kingdom
- Faculty of Biology, Medicine and Health, School of Health Sciences, Division of Informatics, Imaging and Data Sciences, University of Manchester, Manchester, United Kingdom
| | | | - Marco Mottinelli
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, FL 32610, USA
| | - Christophe Mesangeau
- Department of BioMolecular Sciences, School of Pharmacy, University of Mississippi, University, MS 38677, USA
| | - Christopher R McCurdy
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, FL 32610, USA
- UF Translational Drug Development Core, University of Florida, Gainesville, FL 32610, USA
| | - Inga B Fricke
- European Institute for Molecular Imaging (EIMI), Westfälische Wilhelms-Universität (WWU), Münster, Germany
| | - Andreas H. Jacobs
- European Institute for Molecular Imaging (EIMI), Westfälische Wilhelms-Universität (WWU), Münster, Germany
- Department of Geriatrics and Neurology, Johanniter Hospital, Bonn, Germany
| | - Michael Kassiou
- School of Chemistry, The University of Sydney, Sydney, Australia
| | - Hervé Boutin
- Faculty of Biology, Medicine and Health, School of Biological Sciences, Division of Neuroscience and Experimental Psychology, University of Manchester, Manchester, United Kingdom
- Wolfson Molecular Imaging Centre, University of Manchester, Manchester, United Kingdom
| |
Collapse
|
13
|
Cai L, Liow JS, Morse CL, Telu S, Davies R, Frankland MP, Zoghbi SS, Cheng K, Hall MD, Innis RB, Pike VW. Evaluation of 11C-NR2B-SMe and Its Enantiomers as PET Radioligands for Imaging the NR2B Subunit Within the NMDA Receptor Complex in Rats. J Nucl Med 2020; 61:1212-1220. [PMID: 31924728 DOI: 10.2967/jnumed.119.235143] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 12/19/2019] [Indexed: 01/01/2023] Open
Abstract
[S-methyl-11C](±)-7-methoxy-3-(4-(4-(methylthio)phenyl)butyl)-2,3,4,5-tetrahydro-1H-benzo[d]azepin-1-ol (11C-NR2B-SMe) and its enantiomers were synthesized as candidates for imaging the NR2B subunit within the N-methyl-d-aspartate receptor with PET. Methods: Brains were scanned with PET for 90 min after intravenous injection of one of the candidate radioligands into rats. To detect any NR2B-specific binding of radioligand in brain, various preblocking or displacing agents were evaluated for their impact on the PET brain imaging data. Radiometabolites from brain and other tissues were measured ex vivo and in vitro. Results: Each radioligand gave high early whole-brain uptake of radioactivity, followed by a brief fast decline and then a slow final decline. 11C-(S)-NR2B-SMe was studied extensively. Ex vivo measurements showed that radioactivity in rat brain at 30 min after radioligand injection was virtually unchanged radioligand. Only less lipophilic radiometabolites appeared in plasma. High-affinity NR2B ligands, Ro-25-6981, ifenprodil, and CO101244, showed increasing preblocking of whole-brain radioactivity retention with increasing dose (0.01-3.00 mg/kg, intravenously). Five σ1 antagonists (FTC146, BD1407, F3, F4, and NE100) and 4 σ1 agonists ((+)-pentazocine, (±)-PPCC, PRE-084, and (+)-SKF10047) were ineffective preblocking agents, except FTC146 and F4 at a high dose. Two potent σ1 receptor agonists, TC1 and SA4503, showed dose-dependent preblocking effects in the presence or absence of pharmacologic σ1 receptor blockade with FTC146. Conclusion: 11C-(S)-NR2B-SMe has adequate NR2B-specific PET signal in rat brain to warrant further evaluation in higher species. TC1 and SA4503 likely have off-target binding to NR2B in vivo.
Collapse
Affiliation(s)
- Lisheng Cai
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland; and
| | - Jeih-San Liow
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland; and
| | - Cheryl L Morse
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland; and
| | - Sanjay Telu
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland; and
| | - Riley Davies
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland; and
| | - Michael P Frankland
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland; and
| | - Sami S Zoghbi
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland; and
| | - Ken Cheng
- NCATS Chemical Genomics Center, National Institutes of Health, Rockville, Maryland
| | - Matthew D Hall
- NCATS Chemical Genomics Center, National Institutes of Health, Rockville, Maryland
| | - Robert B Innis
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland; and
| | - Victor W Pike
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland; and
| |
Collapse
|
14
|
Lan Y, Bai P, Chen Z, Neelamegam R, Placzek MS, Wang H, Fiedler SA, Yang J, Yuan G, Qu X, Schmidt HR, Song J, Normandin MD, Ran C, Wang C. Novel radioligands for imaging sigma-1 receptor in brain using positron emission tomography (PET). Acta Pharm Sin B 2019; 9:1204-1215. [PMID: 31867166 PMCID: PMC6900558 DOI: 10.1016/j.apsb.2019.07.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2019] [Revised: 06/28/2019] [Accepted: 07/04/2019] [Indexed: 12/18/2022] Open
Abstract
The sigma-1 receptor (σ 1R) is a unique intracellular protein. σ 1R plays a major role in various pathological conditions in the central nervous system (CNS), implicated in several neuropsychiatric disorders. Imaging of σ 1R in the brain using positron emission tomography (PET) could serve as a noninvasively tool for enhancing the understanding of the disease's pathophysiology. Moreover, σ 1R PET tracers can be used for target validation and quantification in diagnosis. Herein, we describe the radiosynthesis, in vivo PET/CT imaging of novel σ 1R 11C-labeled radioligands based on 6-hydroxypyridazinone, [11C]HCC0923 and [11C]HCC0929. Two radioligands have high affinities to σ 1R, with good selectivity. In mice PET/CT imaging, both radioligands showed appropriate kinetics and distributions. Additionally, the specific interactions of two radioligands were reduced by compounds 13 and 15 (self-blocking). Of the two, [11C]HCC0929 was further investigated in positive ligands blocking studies, using classic σ 1R agonist SA 4503 and σ 1R antagonist PD 144418. Both σ 1R ligands could extensively decreased the uptake of [11C]HCC0929 in mice brain. Besides, the biodistribution of major brain regions and organs of mice were determined in vivo. These studies demonstrated that two radioligands, especially [11C]HCC0929, possessed ideal imaging properties and might be valuable tools for non-invasive quantification of σ 1R in brain.
Collapse
Key Words
- 11C-labeled radioligand
- 3D, three-dimensional
- 6-Hydroxypyridazinone
- AF, ammonium formate
- BBB, brain blood barrier
- BP, binding potential
- Brain imaging
- CNS, center nervous systems
- CRPS, complex regional pain syndrome
- DMF, dimethyl formamide
- DMSO, dimethylsulfoxide
- ER, endoplasmic reticulum
- LCP, lipidic cubic phase
- MAM, mitochondria-associated ER membrane
- PCP, phencyclidine
- PET
- PET, positron emission tomography
- TFA, trifluoroacetic acid
- σ1R
- σ1R, sigma-1 receptor
- σ2R, sigma-2 receptor
Collapse
Affiliation(s)
- Yu Lan
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
- Department of Pharmacy, Renmin Hospital of Wuhan University, Wuhan 430060, China
| | - Ping Bai
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | - Zude Chen
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | - Ramesh Neelamegam
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | - Michael S. Placzek
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | - Hao Wang
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | - Stephanie A. Fiedler
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | - Jing Yang
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | - Gengyang Yuan
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | - Xiying Qu
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | - Hayden R. Schmidt
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02129, USA
| | - Jinchun Song
- Department of Pharmacy, Renmin Hospital of Wuhan University, Wuhan 430060, China
| | - Marc D. Normandin
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | - Chongzhao Ran
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | - Changning Wang
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| |
Collapse
|
15
|
Colom M, Vidal B, Zimmer L. Is There a Role for GPCR Agonist Radiotracers in PET Neuroimaging? Front Mol Neurosci 2019; 12:255. [PMID: 31680859 PMCID: PMC6813225 DOI: 10.3389/fnmol.2019.00255] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 10/02/2019] [Indexed: 12/30/2022] Open
Abstract
Positron emission tomography (PET) is a molecular imaging modality that enables in vivo exploration of metabolic processes and especially the pharmacology of neuroreceptors. G protein-coupled receptors (GPCRs) play an important role in numerous pathophysiologic disorders of the central nervous system. Thus, they are targets of choice in PET imaging to bring proof concept of change in density in pathological conditions or in pharmacological challenge. At present, most radiotracers are antagonist ligands. In vitro data suggest that properties differ between GPCR agonists and antagonists: antagonists bind to receptors with a single affinity, whereas agonists are characterized by two different affinities: high affinity for receptors that undergo functional coupling to G-proteins, and low affinity for those that are not coupled. In this context, agonist radiotracers may be useful tools to give functional images of GPCRs in the brain, with high sensitivity to neurotransmitter release. Here, we review all existing PET radiotracers used from animals to humans and their role for understanding the ligand-receptor paradigm of GPCR in comparison with corresponding antagonist radiotracers.
Collapse
Affiliation(s)
- Matthieu Colom
- Lyon Neuroscience Research Center, INSERM, CNRS, Université de Lyon, Lyon, France.,CERMEP, Hospices Civils de Lyon, Bron, France
| | - Benjamin Vidal
- Lyon Neuroscience Research Center, INSERM, CNRS, Université de Lyon, Lyon, France
| | - Luc Zimmer
- Lyon Neuroscience Research Center, INSERM, CNRS, Université de Lyon, Lyon, France.,CERMEP, Hospices Civils de Lyon, Bron, France.,Institut National des Sciences et Techniques Nucléaires, CEA Saclay, Gif-sur-Yvette, France
| |
Collapse
|
16
|
Mansur A, Rabiner EA, Comley RA, Lewis Y, Middleton LT, Huiban M, Passchier J, Tsukada H, Gunn RN. Characterization of 3 PET Tracers for Quantification of Mitochondrial and Synaptic Function in Healthy Human Brain: 18F-BCPP-EF, 11C-SA-4503, and 11C-UCB-J. J Nucl Med 2019; 61:96-103. [PMID: 31324712 DOI: 10.2967/jnumed.119.228080] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 06/04/2019] [Indexed: 11/16/2022] Open
Abstract
Mitochondrial complex 1 is involved in maintaining brain bioenergetics; σ-1 receptor responds to neuronal stress; and synaptic vesicle protein 2A reflects synaptic integrity. Expression of each of these proteins is altered in neurodegenerative diseases. Here, we characterize the kinetic behavior of 3 PET radioligands-18F-BCPP-EF, 11C-SA-4503, and 11C-UCB-J-for the measurement of mitochondrial complex 1, σ-1 receptor, and synaptic vesicle protein 2A, respectively, and determine appropriate analysis workflows for their application in future studies of the in vivo molecular pathology of these diseases. Methods: Twelve human subjects underwent dynamic PET scans with each radioligand, including associated arterial blood sampling. A range of kinetic models was investigated to identify an optimal kinetic analysis method for each radioligand and a suitable acquisition duration. Results: All 3 radioligands readily entered the brain and yielded heterogeneous uptake consistent with the known distribution of the targets. The optimal models determined for the regional estimates of volume of distribution were multilinear analysis 1 (MA1) and the 2-tissue-compartment model for 18F-BCPP-EF, MA1 for 11C-SA-4503, and both MA1 and the 1-tissue-compartment model for 11C-UCB-J. Acquisition times of 70, 80, and 60 min for 18F-BCPP-EF, 11C-SA-4503, 11C-UCB-J, respectively, provided good estimates of regional volume of distribution values. An effect of age was observed on 18F-BCPP-EF and 11C-UCB-J signal in the caudate. Conclusion: These ligands can be assessed for their potential to stratify patients or monitor the progression of molecular neuropathology in neurodegenerative diseases.
Collapse
Affiliation(s)
- Ayla Mansur
- Invicro LLC, London, United Kingdom .,Division of Brain Sciences, Imperial College London, London, United Kingdom
| | - Eugenii A Rabiner
- Invicro LLC, London, United Kingdom.,King's College London, London, United Kingdom
| | | | | | - Lefkos T Middleton
- Neuroepidemiology and Ageing Research Unit, Imperial College London, London, United Kingdom; and
| | | | - Jan Passchier
- Invicro LLC, London, United Kingdom.,Division of Brain Sciences, Imperial College London, London, United Kingdom
| | - Hideo Tsukada
- Hamamatsu Photonics, Hamamatsu City, Shizuoka, Japan
| | | | | |
Collapse
|
17
|
Shen B, Park JH, Hjørnevik T, Cipriano PW, Yoon D, Gulaka PK, Holly D, Behera D, Avery BA, Gambhir SS, McCurdy CR, Biswal S, Chin FT. Radiosynthesis and First-In-Human PET/MRI Evaluation with Clinical-Grade [ 18F]FTC-146. Mol Imaging Biol 2018; 19:779-786. [PMID: 28280965 DOI: 10.1007/s11307-017-1064-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
PURPOSE Sigma-1 receptors (S1Rs) play an important role in many neurological disorders. Simultaneous positron emission tomography (PET)/magnetic resonance imaging (MRI) with S1R radioligands may provide valuable information for diagnosing and guiding treatment for these diseases. Our previously reported S1R radioligand, [18F]FTC-146, demonstrated high affinity for the S1R (K i = 0.0025 nM) and excellent selectivity for the S1R over the sigma-2 receptor (S2Rs; K i = 364 nM) across several species (from mouse to non-human primate). Herein, we report the clinical-grade radiochemistry filed with exploratory Investigational New Drug (eIND) and first-in-human PET/MRI evaluation of [18F]FTC-146. PROCEDURES [18F]FTC-146 is prepared via a direct [18F] fluoride nucleophilic radiolabeling reaction and formulated in 0.9 % NaCl containing no more than 10 % ethanol through sterile filtration. Quality control (QC) was performed based on USP 823 before doses were released for clinical use. The safety and whole body biodistribution of [18F]FTC-146 were evaluated using a simultaneous PET/MR scanner in two representative healthy human subjects. RESULTS [18F]FTC-146 was synthesized with a radiochemical yield of 3.3 ± 0.7 % and specific radioactivity of 8.3 ± 3.3 Ci/μmol (n = 10, decay corrected to EOB). Both radiochemical and chemical purities were >95 %; the prepared doses were stable for 4 h at ambient temperature. All QC test results met specified clinical criteria. The in vivo PET/MRI investigations showed that [18F]FTC-146 rapidly crossed the blood brain barrier and accumulated in S1R-rich regions of the brain. There were also radioactivity distributed in the peripheral organs, i.e., the lungs, spleen, pancreas, and thyroid. Furthermore, insignificant uptake of [18F]FTC-146 was observed in cortical bone and muscle. CONCLUSION A reliable and automated radiosynthesis for providing routine clinical-grade [18F]FTC-146 for human studies was established in a modified GE TRACERlab FXFN. PET/MRI demonstrated the initial tracer biodistribution in humans, and clinical studies investigating different S1R-related diseases are in progress.
Collapse
Affiliation(s)
- Bin Shen
- Molecular Imaging Program at Stanford (MIPS), Departments of Radiology and Bioengineering, Bio-X Program, Stanford University School of Medicine, 1201 Welch Road, PS049, Stanford, CA, 94305-5484, USA
| | - Jun Hyung Park
- Molecular Imaging Program at Stanford (MIPS), Departments of Radiology and Bioengineering, Bio-X Program, Stanford University School of Medicine, 1201 Welch Road, PS049, Stanford, CA, 94305-5484, USA
| | - Trine Hjørnevik
- Molecular Imaging Program at Stanford (MIPS), Departments of Radiology and Bioengineering, Bio-X Program, Stanford University School of Medicine, 1201 Welch Road, PS049, Stanford, CA, 94305-5484, USA.,Department of Diagnostic Physics, Oslo University Hospital, Oslo, Norway.,The Norwegian Medical Cyclotron Centre, Oslo, Norway
| | - Peter W Cipriano
- Molecular Imaging Program at Stanford (MIPS), Departments of Radiology and Bioengineering, Bio-X Program, Stanford University School of Medicine, 1201 Welch Road, PS049, Stanford, CA, 94305-5484, USA
| | - Daehyun Yoon
- Radiological Sciences Laboratory, Department of Radiology, Stanford University, Stanford, CA, 94305, USA
| | - Praveen K Gulaka
- Molecular Imaging Program at Stanford (MIPS), Departments of Radiology and Bioengineering, Bio-X Program, Stanford University School of Medicine, 1201 Welch Road, PS049, Stanford, CA, 94305-5484, USA
| | - Dawn Holly
- Molecular Imaging Program at Stanford (MIPS), Departments of Radiology and Bioengineering, Bio-X Program, Stanford University School of Medicine, 1201 Welch Road, PS049, Stanford, CA, 94305-5484, USA
| | - Deepak Behera
- Molecular Imaging Program at Stanford (MIPS), Departments of Radiology and Bioengineering, Bio-X Program, Stanford University School of Medicine, 1201 Welch Road, PS049, Stanford, CA, 94305-5484, USA
| | - Bonnie A Avery
- Department of Pharmaceutics, P1-27, University of Florida, Gainesville, FL, 32610, USA
| | - Sanjiv S Gambhir
- Molecular Imaging Program at Stanford (MIPS), Departments of Radiology and Bioengineering, Bio-X Program, Stanford University School of Medicine, 1201 Welch Road, PS049, Stanford, CA, 94305-5484, USA
| | - Christopher R McCurdy
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, FL, 32610, USA
| | - Sandip Biswal
- Department of Radiology and Molecular Imaging Program at Stanford (MIPS), Stanford University School of Medicine, 300 Pasteur Drive S-068B, Stanford, CA, 94305, USA.
| | - Frederick T Chin
- Molecular Imaging Program at Stanford (MIPS), Departments of Radiology and Bioengineering, Bio-X Program, Stanford University School of Medicine, 1201 Welch Road, PS049, Stanford, CA, 94305-5484, USA.
| |
Collapse
|
18
|
Kranz M, Bergmann R, Kniess T, Belter B, Neuber C, Cai Z, Deng G, Fischer S, Zhou J, Huang Y, Brust P, Deuther-Conrad W, Pietzsch J. Bridging from Brain to Tumor Imaging: (S)-(-)- and (R)-(+)-[ 18F]Fluspidine for Investigation of Sigma-1 Receptors in Tumor-Bearing Mice. Molecules 2018; 23:E702. [PMID: 29558382 PMCID: PMC6017399 DOI: 10.3390/molecules23030702] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Revised: 03/12/2018] [Accepted: 03/18/2018] [Indexed: 12/12/2022] Open
Abstract
Sigma-1 receptors (Sig1R) are highly expressed in various human cancer cells and hence imaging of this target with positron emission tomography (PET) can contribute to a better understanding of tumor pathophysiology and support the development of antineoplastic drugs. Two Sig1R-specific radiolabeled enantiomers (S)-(-)- and (R)-(+)-[18F]fluspidine were investigated in several tumor cell lines including melanoma, squamous cell/epidermoid carcinoma, prostate carcinoma, and glioblastoma. Dynamic PET scans were performed in mice to investigate the suitability of both radiotracers for tumor imaging. The Sig1R expression in the respective tumors was confirmed by Western blot. Rather low radiotracer uptake was found in heterotopically (subcutaneously) implanted tumors. Therefore, a brain tumor model (U87-MG) with orthotopic implantation was chosen to investigate the suitability of the two Sig1R radiotracers for brain tumor imaging. High tumor uptake as well as a favorable tumor-to-background ratio was found. These results suggest that Sig1R PET imaging of brain tumors with [18F]fluspidine could be possible. Further studies with this tumor model will be performed to confirm specific binding and the integrity of the blood-brain barrier (BBB).
Collapse
Affiliation(s)
- Mathias Kranz
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, 04318 Leipzig, Germany.
- Department of Diagnostic Radiology, PET Center, Yale University School of Medicine, New Haven, CT 06519, USA.
| | - Ralf Bergmann
- Department of Radiopharmaceutical and Chemical Biology, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany.
| | - Torsten Kniess
- Department of Radiopharmaceutical and Chemical Biology, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany.
| | - Birgit Belter
- Department of Radiopharmaceutical and Chemical Biology, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany.
| | - Christin Neuber
- Department of Radiopharmaceutical and Chemical Biology, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany.
| | - Zhengxin Cai
- Department of Diagnostic Radiology, PET Center, Yale University School of Medicine, New Haven, CT 06519, USA.
| | - Gang Deng
- Department of Neurosurgery and Biomedical Engineering, Yale University School of Medicine, New Haven, CT 06519, USA.
| | - Steffen Fischer
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, 04318 Leipzig, Germany.
| | - Jiangbing Zhou
- Department of Neurosurgery and Biomedical Engineering, Yale University School of Medicine, New Haven, CT 06519, USA.
| | - Yiyun Huang
- Department of Diagnostic Radiology, PET Center, Yale University School of Medicine, New Haven, CT 06519, USA.
| | - Peter Brust
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, 04318 Leipzig, Germany.
| | - Winnie Deuther-Conrad
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, 04318 Leipzig, Germany.
| | - Jens Pietzsch
- Department of Radiopharmaceutical and Chemical Biology, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany.
- Technische Universität Dresden, School of Science, Faculty of Chemistry and Food Chemistry, 01062 Dresden, Germany.
| |
Collapse
|
19
|
Hjørnevik T, Cipriano PW, Shen B, Park JH, Gulaka P, Holley D, Gandhi H, Yoon D, Mittra ES, Zaharchuk G, Gambhir SS, McCurdy CR, Chin FT, Biswal S. Biodistribution and Radiation Dosimetry of 18F-FTC-146 in Humans. J Nucl Med 2017; 58:2004-2009. [PMID: 28572487 PMCID: PMC6944163 DOI: 10.2967/jnumed.117.192641] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2017] [Accepted: 05/16/2017] [Indexed: 01/27/2023] Open
Abstract
The purpose of this study was to assess safety, biodistribution, and radiation dosimetry in humans for the highly selective σ-1 receptor PET agent 18F-6-(3-fluoropropyl)-3-(2-(azepan-1-yl)ethyl)benzo[d]thiazol-2(3H)-one (18F-FTC-146). Methods: Ten healthy volunteers (5 women, 5 men; age ± SD, 34.3 ± 6.5 y) were recruited, and written informed consent was obtained from all participants. Series of whole-body PET/MRI examinations were acquired for up to 3 h after injection (357.2 ± 48.8 MBq). Blood samples were collected, and standard vital signs (heart rate, pulse oximetry, and body temperature) were monitored at regular intervals. Regions of interest were delineated, time-activity curves were calculated, and organ uptake and dosimetry were estimated. Results: All subjects tolerated the PET/MRI examination well, and no adverse reactions to 18F-FTC-146 were reported. High accumulation of 18F-FTC-146 was observed in σ-1 receptor-dense organs such as the pancreas and spleen, moderate uptake in the brain and myocardium, and low uptake in bone and muscle. High uptake was also observed in the kidneys and bladder, indicating renal tracer clearance. The effective dose of 18F-FTC-146 was 0.0259 ± 0.0034 mSv/MBq (range, 0.0215-0.0301 mSv/MBq). Conclusion: First-in-human studies with clinical-grade 18F-FTC-146 were successful. Injection of 18F-FTC-146 is safe, and absorbed doses are acceptable. The potential of 18F-FTC-146 as an imaging agent for a variety of neuroinflammatory diseases is currently under investigation.
Collapse
Affiliation(s)
- Trine Hjørnevik
- Department of Radiology, Stanford University, Stanford, California
- Department of Diagnostic Physics, Oslo University Hospital, Oslo, Norway
- The Norwegian Medical Cyclotron Centre, Oslo, Norway
| | - Peter W Cipriano
- Department of Radiology, Stanford University, Stanford, California
| | - Bin Shen
- Department of Radiology, Stanford University, Stanford, California
| | - Jun Hyung Park
- Department of Radiology, Stanford University, Stanford, California
| | - Praveen Gulaka
- Department of Radiology, Stanford University, Stanford, California
| | - Dawn Holley
- Department of Radiology, Stanford University, Stanford, California
| | - Harsh Gandhi
- Department of Radiology, Stanford University, Stanford, California
| | - Daehyun Yoon
- Department of Radiology, Stanford University, Stanford, California
| | - Erik S Mittra
- Department of Radiology, Stanford University, Stanford, California
| | - Greg Zaharchuk
- Department of Radiology, Stanford University, Stanford, California
| | - Sanjiv S Gambhir
- Department of Radiology, Stanford University, Stanford, California
| | - Christopher R McCurdy
- Department of Medicinal Chemistry, University of Florida, Gainesville, Florida; and
- UF Translational Drug Development Core, University of Florida, Gainesville, Florida
| | - Frederick T Chin
- Department of Radiology, Stanford University, Stanford, California
| | - Sandip Biswal
- Department of Radiology, Stanford University, Stanford, California
| |
Collapse
|
20
|
Baum E, Cai Z, Bois F, Holden D, Lin SF, Lara-Jaime T, Kapinos M, Chen Y, Deuther-Conrad W, Fischer S, Dukic-Stefanovic S, Bunse P, Wünsch B, Brust P, Jia H, Huang Y. PET Imaging Evaluation of Four σ 1 Radiotracers in Nonhuman Primates. J Nucl Med 2017; 58:982-988. [PMID: 28232607 DOI: 10.2967/jnumed.116.188052] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 02/09/2017] [Indexed: 01/24/2023] Open
Abstract
The σ1 receptors (S1Rs) are implicated in a variety of diseases including Alzheimer disease and cancer. Previous PET S1R radiotracers are characterized by slow kinetics or off-target binding that impedes their use in humans. Here, we report the first PET imaging evaluation in rhesus monkeys of 4 18F-labeled spirocyclic piperidine-based PET radiotracers (18F-1 to 18F-4). Methods: Baseline scans for the 4 radiotracers were obtained on an adult male rhesus monkey. Blocking scans were obtained with the S1R-selective agonist SA4503 to assess binding specificity of 18F-2 and 18F-4 Arterial input functions were measured, and binding parameters were determined with kinetic modeling analysis. Results: In the rhesus brain, all 4 radiotracers showed high and fast uptake. Tissue activity washout was rapid for 18F-2 and 18F-4, and much slower for 18F-1 and 18F-3, in line with their respective in vitro S1R-binding affinities. Both the 1-tissue-compartment and multilinear analysis-1 kinetic models provided good fits of time-activity curves and reliable estimates of distribution volume. Regional distribution volume values were highest in the cingulate cortex and lowest in the thalamus for all radiotracers. 18F-4 showed greater differential uptake across brain regions and 3-fold-higher binding potential than 18F-2 SA4503 at the dose of 0.5 mg/kg blocked approximately 85% (18F-2) and 95% (18F-4) of radiotracer binding. Conclusion: Tracers 18F-2 and 18F-4 displayed high brain uptake and fast tissue kinetics, with 18F-4 having higher specific binding signals than 18F-2 in the same monkey. Taken together, these data indicate that both 18F-2 and 18F-4 possess the requisite kinetic and imaging properties as viable PET tracers for imaging S1R in the human brain.
Collapse
Affiliation(s)
- Evan Baum
- PET Center, Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut
| | - Zhengxin Cai
- PET Center, Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut
| | - Frederic Bois
- PET Center, Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut
| | - Daniel Holden
- PET Center, Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut
| | - Shu-Fei Lin
- PET Center, Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut
| | - Teresa Lara-Jaime
- PET Center, Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut
| | - Michael Kapinos
- PET Center, Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut
| | - Yuanyuan Chen
- Ministry of Education Key Laboratory of Radiopharmaceuticals, College of Chemistry, Beijing Normal University, Beijing, China
| | - Winnie Deuther-Conrad
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Leipzig, Germany; and
| | - Steffen Fischer
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Leipzig, Germany; and
| | - Sladjana Dukic-Stefanovic
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Leipzig, Germany; and
| | - Paul Bunse
- Department of Pharmaceutical and Medicinal Chemistry, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Bernhard Wünsch
- Department of Pharmaceutical and Medicinal Chemistry, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Peter Brust
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Leipzig, Germany; and
| | - Hongmei Jia
- Ministry of Education Key Laboratory of Radiopharmaceuticals, College of Chemistry, Beijing Normal University, Beijing, China
| | - Yiyun Huang
- PET Center, Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut
| |
Collapse
|
21
|
He Y, Xie F, Ye J, Deuther-Conrad W, Cui B, Wang L, Lu J, Steinbach J, Brust P, Huang Y, Lu J, Jia H. 1-(4-[ 18F]Fluorobenzyl)-4-[(tetrahydrofuran-2-yl)methyl]piperazine: A Novel Suitable Radioligand with Low Lipophilicity for Imaging σ 1 Receptors in the Brain. J Med Chem 2017; 60:4161-4172. [PMID: 28409931 DOI: 10.1021/acs.jmedchem.6b01723] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We have designed and synthesized novel piperazine compounds with low lipophilicity as σ1 receptor ligands. 1-(4-Fluorobenzyl)-4-[(tetrahydrofuran-2-yl)methyl]piperazine (10) possessed a low nanomolar σ1 receptor affinity and a high selectivity toward the vesicular acetylcholine transporter (>2000-fold), σ2 receptors (52-fold), and adenosine A2A, adrenergic α2, cannabinoid CB1, dopamine D1, D2L, γ-aminobutyric acid A (GABAA), NMDA, melatonin MT1, MT2, and serotonin 5-HT1 receptors. The corresponding radiotracer [18F]10 demonstrated high brain uptake and extremely high brain-to-blood ratios in biodistribution studies in mice. Pretreatment with the selective σ1 receptor agonist SA4503 significantly reduced the level of accumulation of the radiotracer in the brain. No radiometabolite of [18F]10 was observed to enter the brain. Positron emission tomography and magnetic resonance imaging confirmed suitable kinetics and a high specific binding of [18F]10 to σ1 receptors in rat brain. Ex vivo autoradiography showed a reduced level of binding of [18F]10 in the cortex and hippocampus of the senescence-accelerated prone (SAMP8) compared to that of the senescence-accelerated resistant (SAMR1) mice, indicating the potential dysfunction of σ1 receptors in Alzheimer's disease.
Collapse
Affiliation(s)
- Yingfang He
- Key Laboratory of Radiopharmaceuticals (Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University , Beijing, China
| | - Fang Xie
- Key Laboratory of Radiopharmaceuticals (Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University , Beijing, China
| | - Jiajun Ye
- Key Laboratory of Radiopharmaceuticals (Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University , Beijing, China
| | - Winnie Deuther-Conrad
- Helmholtz-Zentrum Dresden-Rossendorf , Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, 04318 Leipzig, Germany
| | - Bixiao Cui
- Department of Nuclear Medicine, Xuanwu Hospital Capital Medical University , Beijing, China
| | - Liang Wang
- Key Laboratory of Radiopharmaceuticals (Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University , Beijing, China
| | - Jie Lu
- Key Laboratory of Radiopharmaceuticals (Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University , Beijing, China
| | - Jörg Steinbach
- Helmholtz-Zentrum Dresden-Rossendorf , Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, 04318 Leipzig, Germany
| | - Peter Brust
- Helmholtz-Zentrum Dresden-Rossendorf , Institute of Radiopharmaceutical Cancer Research, Department of Neuroradiopharmaceuticals, 04318 Leipzig, Germany
| | - Yiyun Huang
- Yale PET Center, Department of Radiology and Biomedical Imaging, Yale University School of Medicine , New Haven, Connecticut 06520-8048, United States
| | - Jie Lu
- Department of Nuclear Medicine, Xuanwu Hospital Capital Medical University , Beijing, China
| | - Hongmei Jia
- Key Laboratory of Radiopharmaceuticals (Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University , Beijing, China
| |
Collapse
|
22
|
Yang D, Comeau A, Bowen WD, Mach RH, Ross BD, Hong H, Van Dort ME. Design and Investigation of a [ 18F]-Labeled Benzamide Derivative as a High Affinity Dual Sigma Receptor Subtype Radioligand for Prostate Tumor Imaging. Mol Pharm 2017; 14:770-780. [PMID: 28135101 DOI: 10.1021/acs.molpharmaceut.6b01020] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
High overexpression of sigma (σ) receptors (σ1 and σ2 subtypes) in a variety of human solid tumors has prompted the development of σ receptor-targeting radioligands, as imaging agents for tumor detection. A majority of these radioligands to date target the σ2 receptor, a potential marker of tumor proliferative status. The identification of approximately equal proportions of both σ receptor subtypes in prostate tumors suggests that a high affinity, dual σ receptor-targeting radioligand could potentially provide enhanced tumor targeting efficacy in prostate cancer. To accomplish this goal, we designed a series of ligands which bind to both σ receptor subtypes with high affinity. Ligand 3a in this series, displaying optimal dual σ receptor subtype affinity (σ1, 6.3 nM; σ2, 10.2 nM) was radiolabeled with fluorine-18 (18F) to give [18F]3a and evaluated as a σ receptor-targeting radioligand in the mouse PC-3 prostate tumor model. Cellular assays with PC-3 cells demonstrated that a major proportion of [18F]3a was localized to cell surface σ receptors, while ∼10% of [18F]3a was internalized within cells after incubation for 3.5 h. Serial PET imaging in mice bearing PC-3 tumors revealed that uptake of [18F]3a was 1.6 ± 0.8, 4.4 ± 0.3, and 3.6 ± 0.6% ID/g (% injection dose per gram) in σ receptor-positive prostate tumors at 15 min, 1.5 h, and 3.5 h postinjection, respectively (n = 3) resulting in clear tumor visualization. Blocking studies conducted with haloperidol (a nonselective inhibitor for both σ receptor subtypes) confirmed that the uptake of [18F]3a was σ receptor-mediated. Histology analysis confirmed similar expression of σ1 and σ2 in PC-3 tumors which was significantly greater than its expression in normal organs/tissues such as liver, kidney, and muscle. Metabolite studies revealed that >50% of radioactivity in PC-3 tumors at 30 min postinjection represented intact [18F]3a. Prominent σ receptor-specific uptake of [18F]3a in prostate tumors and its subsequent clear visualization with PET imaging indicate potential utility for the diagnosis of prostate carcinoma.
Collapse
Affiliation(s)
- Dongzhi Yang
- Center for Molecular Imaging, Department of Radiology, University of Michigan , Ann Arbor, Michigan 48109-2200, United States.,Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University , Xuzhou, Jiangsu 221004, China
| | - Anthony Comeau
- Department of Molecular Pharmacology, Physiology & Biotechnology, Brown University , Providence, Rhode Island 02912, United States
| | - Wayne D Bowen
- Department of Molecular Pharmacology, Physiology & Biotechnology, Brown University , Providence, Rhode Island 02912, United States
| | - Robert H Mach
- Department of Radiology, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
| | - Brian D Ross
- Center for Molecular Imaging, Department of Radiology, University of Michigan , Ann Arbor, Michigan 48109-2200, United States
| | - Hao Hong
- Center for Molecular Imaging, Department of Radiology, University of Michigan , Ann Arbor, Michigan 48109-2200, United States
| | - Marcian E Van Dort
- Center for Molecular Imaging, Department of Radiology, University of Michigan , Ann Arbor, Michigan 48109-2200, United States
| |
Collapse
|
23
|
Ramakrishnan NK, Visser AKD, Rybczynska AA, Nyakas CJ, Luiten PGM, Kwizera C, Sijbesma JWA, Elsinga PH, Ishiwata K, Dierckx RAJO, van Waarde A. Sigma-1 Agonist Binding in the Aging Rat Brain: a MicroPET Study with [(11)C]SA4503. Mol Imaging Biol 2016; 18:588-97. [PMID: 26637208 PMCID: PMC4927617 DOI: 10.1007/s11307-015-0917-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
PURPOSE Sigma-1 receptor ligands modulate the release of several neurotransmitters and intracellular calcium signaling. We examined the binding of a radiolabeled sigma-1 agonist in the aging rat brain with positron emission tomography (PET). PROCEDURES Time-dependent uptake of [(11)C]SA4503 was measured in the brain of young (1.5 to 3 months) and aged (18 to 32 months) Wistar Hannover rats, and tracer-kinetic models were fitted to this data, using metabolite-corrected plasma radioactivity as input function. RESULTS In aged animals, the injected probe was less rapidly metabolized and cleared. Logan graphical analysis and a 2-tissue compartment model (2-TCM) fit indicated changes of total distribution volume (V T) and binding potential (BP ND) of the tracer. BP ND was reduced particularly in the (hypo)thalamus, pons, and medulla. CONCLUSIONS Some areas showed reductions of ligand binding with aging whereas binding in other areas (cortex) was not significantly affected.
Collapse
Affiliation(s)
- Nisha K Ramakrishnan
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands
- Division of Imaging Sciences and Biomedical Engineering, King's College London, Strand, London, WC2R 2LS, UK
| | - Anniek K D Visser
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands
| | - Anna A Rybczynska
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands
| | - Csaba J Nyakas
- Research Group of Molecular Neurobiology, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
- Department of Morphology and Physiology, Semmelweis University, 17 Vas, H-1088, Budapest, Hungary
| | - Paul G M Luiten
- Research Group of Molecular Neurobiology, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
- Department of Morphology and Physiology, Semmelweis University, 17 Vas, H-1088, Budapest, Hungary
| | - Chantal Kwizera
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands
| | - Jurgen W A Sijbesma
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands
| | - Philip H Elsinga
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands
| | - Kiichi Ishiwata
- Southern Tohoku Research Institute for Neuroscience, 7-115 Yatsuyamada, Koriyama, 963-8052, Japan
| | - Rudi A J O Dierckx
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands
| | - Aren van Waarde
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands.
| |
Collapse
|
24
|
Yasui Y, Su TP. Potential Molecular Mechanisms on the Role of the Sigma-1 Receptor in the Action of Cocaine and Methamphetamine. ACTA ACUST UNITED AC 2016; 5. [PMID: 27088037 DOI: 10.4303/jdar/235970] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The sigma-1 receptor (Sig-1R) is an endoplasmic reticulum membrane protein that involves a wide range of physiological functions. The Sig-1R has been shown to bind psychostimulants including cocaine and methamphetamine (METH) and thus has been implicated in the actions of those psychostimulants. For example, it has been demonstrated that the Sig-1R antagonists mitigate certain behavioral and cellular effects of psychostimulants including hyperactivity and neurotoxicity. Thus, the Sig-1R has become a potential therapeutic target of medication development against drug abuse that differs from traditional monoamine-related strategies. In this review, we will focus on the molecular mechanisms of the Sig-1R and discuss in such a manner with a hope to further understand or unveil unexplored relations between the Sig-1R and the actions of cocaine and METH, particularly in the context of cellular biological relevance.
Collapse
Affiliation(s)
- Yuko Yasui
- Cellular Pathobiology Section, Integrative Neuroscience Research Branch, Intramural Research Program, National Institute on Drug Abuse, NIH, DHHS, Baltimore, Maryland 21224
| | - Tsung-Ping Su
- Cellular Pathobiology Section, Integrative Neuroscience Research Branch, Intramural Research Program, National Institute on Drug Abuse, NIH, DHHS, Baltimore, Maryland 21224
| |
Collapse
|
25
|
Kitamura Y, Kozaka T, Miwa D, Uno I, Azim MAU, Ogawa K, Taki J, Kinuya S, Shiba K. Synthesis and evaluation of a new vesamicol analog o-[(11)C]methyl-trans-decalinvesamicol as a PET ligand for the vesicular acetylcholine transporter. Ann Nucl Med 2015; 30:122-9. [PMID: 26608176 DOI: 10.1007/s12149-015-1039-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 11/08/2015] [Indexed: 11/26/2022]
Abstract
INTRODUCTION We focused on the vesicle acetyl choline transporter (VAChT) as target for early diagnosis of Alzheimer's diseases because the dysfunction of the cholinergic nervous system is closely associated with the symptoms of AD, such as problem in recognition, memory, and learning. Due to its low binding affinity for the sigma receptors (σ-1 and σ-2), o-methyl-trans-decalinvesamicol (OMDV) demonstrated a high binding affinity and selectivity for vesicular acetyl choline transporter (VAChT). [(11)C]OMDV was prepared and investigated the potential as a new PET ligand for VAChT imaging through in vivo evaluation. METHOD [(11)C]OMDV was prepared by a palladium-promoted cross-coupling reaction using [(11)C]methyl iodide, with a radiochemical yield of 60-75%, a radiochemical purity of greater than 98%, and a specific activity of 5-10 TBq/mmol 30 min after EOB. In vivo biodistribution study of [(11)C]OMDV in blood, brain regions and major organs of rats was performed at 2, 10, 30 and 60 min post-injection. In vivo blocking study and PET-CT imaging study were performed to check the binding selectivity of [(11)C]OMDV for VAChT. RESULTS In vivo studies demonstrated [(11)C]OMDV passage through the blood-brain barrier (BBB) and accumulation in the rat brain. The regional brain accumulation of [(11)C]OMDV was significantly inhibited by co-administration of vesamicol. In contrast, brain accumulation of [(11)C]OMDV was not significantly altered by co-administration of (+)-pentazocine, a selective σ-1 receptor ligand, or (+)-3-(3-hydroxyphenyl)-N-propylpiperidine [(+)-3-PPP], a σ-1 and σ-2 receptor ligand. PET-CT imaging revealed inhibition of [(11)C]OMDV accumulation in the brain by co-administration of vesamicol. CONCLUSION [(11)C]OMDV selectively binds to VAChT with high affinity in the rat brain in vivo, and that [(11)C]OMDV may be utilized in the future as a specific VAChT ligand for PET imaging.
Collapse
Affiliation(s)
- Yoji Kitamura
- Division of Tracer Kinetics, Advanced Science Research Center, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa, 920-8640, Japan.
| | - Takashi Kozaka
- Division of Tracer Kinetics, Advanced Science Research Center, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa, 920-8640, Japan.
| | - Daisuke Miwa
- Division of Tracer Kinetics, Advanced Science Research Center, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa, 920-8640, Japan
| | - Izumi Uno
- Division of Tracer Kinetics, Advanced Science Research Center, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa, 920-8640, Japan
- Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa, 920-8640, Japan
| | - Mohammad Anwar-Ul Azim
- National Institute of Nuclear Medicine and Allied Sciences, Bangladesh Atomic Energy Commission, BSM Medical University Campus, Block-D, 7th-10th floor, Shahbagh, Dhaka, 1000, Bangladesh
| | - Kazuma Ogawa
- Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa, 920-8640, Japan
| | - Junichi Taki
- Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa, 920-8640, Japan
| | - Seigo Kinuya
- Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa, 920-8640, Japan
| | - Kazuhiro Shiba
- Division of Tracer Kinetics, Advanced Science Research Center, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa, 920-8640, Japan.
| |
Collapse
|
26
|
Further validation to support clinical translation of [(18)F]FTC-146 for imaging sigma-1 receptors. EJNMMI Res 2015; 5:49. [PMID: 26384292 PMCID: PMC4573970 DOI: 10.1186/s13550-015-0122-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 08/11/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND This study aims to further evaluate the specificity and selectivity of [(18)F]FTC-146 and obtain additional data to support its clinical translation. METHODS The binding of [(19)F]FTC-146 to vesicular acetylcholine transporter (VAChT) was evaluated using [(3)H]vesamicol and PC12(A123.7) cells in an in vitro binding assay. The uptake and kinetics of [(18)F]FTC-146 in S1R-knockout mice (S1R-KO) compared to wild-type (WT) littermates was assessed using dynamic positron emission tomography (PET) imaging. Ex vivo autoradiography and histology were conducted using a separate cohort of S1R-KO/WT mice, and radiation dosimetry was calculated from WT mouse data (extrapolated for human dosing). Toxicity studies in Sprague-Dawley rats were performed with a dose equivalent to 250× the anticipated clinical dose of [(19)F]FTC-146 mass. RESULTS AND DISCUSSION VAChT binding assay results verified that [(19)F]FTC-146 displays negligible affinity for VAChT (K i = 450 ± 80 nM) compared to S1R. PET images demonstrated significantly higher tracer uptake in WT vs. S1R-KO brain (4.57 ± 1.07 vs. 1.34 ± 0.4 %ID/g at 20-25 min, n = 4, p < 0.05). In S1R-KO mice, it was shown that rapid brain uptake and clearance 10 min post-injection, which are consistent with previous S1R-blocking studies in mice. Three- to fourfold higher tracer uptake was observed in WT relative to S1R-KO mouse brains by ex vivo autoradiography. S1R staining coincided well with the autoradiographic data in all examined brain regions (r (2) = 0.85-0.95). Biodistribution results further demonstrated high [(18)F]FTC-146 accumulation in WT relative to KO mouse brain and provided quantitative information concerning tracer uptake in S1R-rich organs (e.g., heart, lung, pancreas) for WT mice vs. age-matched S1R-KO mice. The maximum allowed dose per scan in humans as extrapolated from mouse dosimetry was 33.19 mCi (1228.03 MBq). No significant toxicity was observed even at a 250X dose of the maximum carrier mass [(19)F]FTC-146 expected to be injected for human studies. CONCLUSIONS Together, these data indicate that [(18)F]FTC-146 binds specifically to S1Rs and is a highly promising radiotracer ready for clinical translation to investigate S1R-related diseases.
Collapse
|
27
|
Xie F, Bergmann R, Kniess T, Deuther-Conrad W, Mamat C, Neuber C, Liu B, Steinbach J, Brust P, Pietzsch J, Jia H. (18)F-Labeled 1,4-Dioxa-8-azaspiro[4.5]decane Derivative: Synthesis and Biological Evaluation of a σ1 Receptor Radioligand with Low Lipophilicity as Potent Tumor Imaging Agent. J Med Chem 2015; 58:5395-407. [PMID: 26090686 DOI: 10.1021/acs.jmedchem.5b00593] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We report the syntheses and evaluation of series of novel piperidine compounds with low lipophilicity as σ1 receptor ligands. 8-(4-(2-Fluoroethoxy)benzyl)-1,4-dioxa-8-azaspiro[4.5]decane (5a) possessed high affinity (K(i) = 5.4 ± 0.4 nM) for σ1 receptors and selectivity for σ2 receptors (30-fold) and the vesicular acetylcholine transporter (1404-fold). [(18)F]5a was prepared using a one-pot, two-step labeling procedure in an automated synthesis module, with a radiochemical purity of >95%, and a specific activity of 25-45 GBq/μmol. Cellular association, biodistribution, and autoradiography with blocking experiments indicated specific binding of [(18)F]5a to σ1 receptors in vitro and in vivo. Small animal positron emission tomography (PET) imaging using mouse tumor xenograft models demonstrated a high accumulation in human carcinoma and melanoma. Treatment with haloperidol significantly reduced the accumulation of the radiotracer in tumors. These findings suggest that radiotracer with suitable lipophilicity and appropriate affinity for σ1 receptors could be used for tumor imaging.
Collapse
Affiliation(s)
- Fang Xie
- †Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, POB 510119, D-01314 Dresden, Germany.,‡Key Laboratory of Radiopharmaceuticals (Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Ralf Bergmann
- †Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, POB 510119, D-01314 Dresden, Germany
| | - Torsten Kniess
- †Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, POB 510119, D-01314 Dresden, Germany
| | - Winnie Deuther-Conrad
- †Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, POB 510119, D-01314 Dresden, Germany
| | - Constantin Mamat
- †Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, POB 510119, D-01314 Dresden, Germany.,§Technische Universität Dresden, Department of Chemistry and Food Chemistry, D-01062 Dresden, Germany
| | - Christin Neuber
- †Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, POB 510119, D-01314 Dresden, Germany
| | - Boli Liu
- ‡Key Laboratory of Radiopharmaceuticals (Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Jörg Steinbach
- †Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, POB 510119, D-01314 Dresden, Germany.,§Technische Universität Dresden, Department of Chemistry and Food Chemistry, D-01062 Dresden, Germany
| | - Peter Brust
- †Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, POB 510119, D-01314 Dresden, Germany
| | - Jens Pietzsch
- †Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, POB 510119, D-01314 Dresden, Germany.,§Technische Universität Dresden, Department of Chemistry and Food Chemistry, D-01062 Dresden, Germany
| | - Hongmei Jia
- ‡Key Laboratory of Radiopharmaceuticals (Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| |
Collapse
|
28
|
Chen YY, Wang X, Zhang JM, Deuther-Conrad W, Zhang XJ, Huang Y, Li Y, Ye JJ, Cui MC, Steinbach J, Brust P, Liu BL, Jia HM. Synthesis and evaluation of a 18F-labeled spirocyclic piperidine derivative as promising σ1 receptor imaging agent. Bioorg Med Chem 2014; 22:5270-8. [DOI: 10.1016/j.bmc.2014.08.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 07/18/2014] [Accepted: 08/05/2014] [Indexed: 12/16/2022]
|
29
|
Banister SD, Manoli M, Kassiou M. The development of radiotracers for imaging sigma (σ) receptors in the central nervous system (CNS) using positron emission tomography (PET). J Labelled Comp Radiopharm 2014; 56:215-24. [PMID: 24285328 DOI: 10.1002/jlcr.3010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Revised: 11/19/2012] [Accepted: 11/20/2012] [Indexed: 11/10/2022]
Abstract
Sigma (σ) receptors are unique mammalian proteins, distributed in the central nervous system and elsewhere, which are increasingly implicated in the pathophysiology of virtually all major central nervous system disorders. The heterogeneous but wide distribution of σ1 in the brain has prompted the development of selective radiotracers for imaging these sites using positron emission tomography (PET). To date, some 50 carbon-11-labelled and fluorine-18-labelled candidate PET radioligands targeting σ receptors have been reported. The historical development of selective σ1 receptor ligands as potential PET imaging agents, as well as the radiochemistry and application of the most recently developed examples, is described herein.
Collapse
Affiliation(s)
- Samuel D Banister
- Brain and Mind Research Institute, The University of Sydney, NSW, 2050, Australia; School of Chemistry, The University of Sydney, NSW, 2006, Australia
| | | | | |
Collapse
|
30
|
Matsumoto RR, Nguyen L, Kaushal N, Robson MJ. Sigma (σ) receptors as potential therapeutic targets to mitigate psychostimulant effects. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2014; 69:323-86. [PMID: 24484982 DOI: 10.1016/b978-0-12-420118-7.00009-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Many psychostimulants, including cocaine and methamphetamine, interact with sigma (σ) receptors at physiologically relevant concentrations. The potential therapeutic relevance of this interaction is underscored by the ability to selectively target σ receptors to mitigate many behavioral and physiological effects of psychostimulants in animal and cell-based model systems. This chapter begins with an overview of these enigmatic proteins. Provocative preclinical data showing that σ ligands modulate an array of cocaine and methamphetamine effects are summarized, along with emerging areas of research. Together, the literature suggests targeting of σ receptors as an innovative option for combating undesired actions of psychostimulants through both neuronal and glial mechanisms.
Collapse
Affiliation(s)
- Rae R Matsumoto
- West Virginia University, One Medical Center Drive, Morgantown, West Virginia, USA.
| | - Linda Nguyen
- West Virginia University, One Medical Center Drive, Morgantown, West Virginia, USA
| | - Nidhi Kaushal
- West Virginia University, One Medical Center Drive, Morgantown, West Virginia, USA
| | - Matthew J Robson
- West Virginia University, One Medical Center Drive, Morgantown, West Virginia, USA
| |
Collapse
|
31
|
James ML, Shen B, Nielsen CH, Behera D, Buckmaster CL, Mesangeau C, Zavaleta C, Vuppala PK, Jamalapuram S, Avery BA, Lyons DM, McCurdy CR, Biswal S, Gambhir SS, Chin FT. Evaluation of σ-1 receptor radioligand 18F-FTC-146 in rats and squirrel monkeys using PET. J Nucl Med 2014; 55:147-53. [PMID: 24337599 PMCID: PMC4170105 DOI: 10.2967/jnumed.113.120261] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED The noninvasive imaging of σ-1 receptors (S1Rs) could provide insight into their role in different diseases and lead to novel diagnostic/treatment strategies. The main objective of this study was to assess the S1R radiotracer (18)F-FTC-146 in rats. Preliminary squirrel monkey imaging and human serum/liver microsome studies were performed to gain information about the potential of (18)F-FTC-146 for eventual clinical translation. METHODS The distribution and stability of (18)F-FTC-146 in rats were assessed via PET/CT, autoradiography, γ counting, and high-performance liquid chromatography (HPLC). Preliminary PET/MRI of squirrel monkey brain was conducted along with HPLC assessment of (18)F-FTC-146 stability in monkey plasma and human serum. RESULTS Biodistribution studies showed that (18)F-FTC-146 accumulated in S1R-rich rat organs, including the lungs, pancreas, spleen, and brain. Pretreatment with known S1R compounds, haloperidol, or BD1047, before radioligand administration, significantly attenuated (18)F-FTC-146 accumulation in all rat brain regions by approximately 85% (P < 0.001), suggesting radiotracer specificity for S1Rs. Similarly, PET/CT and autoradiography results demonstrated accumulation of (18)F-FTC-146 in rat brain regions known to contain S1Rs and that this uptake could be blocked by BD1047 pretreatment. Ex vivo analysis of (18)F-FTC-146 in the brain showed that only intact radiotracer was present at 15, 30, and 60 min, whereas rapid metabolism of residual (18)F-FTC-146 was observed in rat plasma. Preliminary monkey PET/MRI studies demonstrated specific accumulation of (18)F-FTC-146 in the brain (mainly in cortical structures, cerebellum, and vermis) that could be attenuated by pretreatment with haloperidol. HPLC of monkey plasma suggested radioligand metabolism, whereas (18)F-FTC-146 appeared to be stable in human serum. Finally, liver microsome studies revealed that (18)F-FTC-146 has a longer half-life in human microsomes, compared with rodents. CONCLUSION Together, these results indicate that (18)F-FTC-146 is a promising tool for visualizing S1Rs in preclinical studies and that it has potential for mapping these sites in the human brain.
Collapse
Affiliation(s)
- Michelle L. James
- Molecular Imaging Program at Stanford (MIPS) Department of Radiology, Stanford University, Stanford, California
| | - Bin Shen
- Molecular Imaging Program at Stanford (MIPS) Department of Radiology, Stanford University, Stanford, California
| | - Carsten H. Nielsen
- Molecular Imaging Program at Stanford (MIPS) Department of Radiology, Stanford University, Stanford, California
- Cluster for Molecular Imaging and Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Deepak Behera
- Molecular Imaging Program at Stanford (MIPS) Department of Radiology, Stanford University, Stanford, California
| | | | - Christophe Mesangeau
- Department of Medicinal Chemistry, University of Mississippi, University, Mississippi
| | - Cristina Zavaleta
- Molecular Imaging Program at Stanford (MIPS) Department of Radiology, Stanford University, Stanford, California
| | - Pradeep K. Vuppala
- Department of Pharmaceutics, University of Mississippi, University, Mississippi
| | | | - Bonnie A. Avery
- Department of Pharmaceutics, University of Mississippi, University, Mississippi
| | - David M. Lyons
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, California
| | | | - Sandip Biswal
- Molecular Imaging Program at Stanford (MIPS) Department of Radiology, Stanford University, Stanford, California
| | - Sanjiv S. Gambhir
- Molecular Imaging Program at Stanford (MIPS) Department of Radiology, Stanford University, Stanford, California
- Department of Bioengineering, Department of Materials Science and Engineering, Stanford University, Stanford, California
| | - Frederick T. Chin
- Molecular Imaging Program at Stanford (MIPS) Department of Radiology, Stanford University, Stanford, California
| |
Collapse
|
32
|
Jin H, Fan J, Zhang X, Li J, Flores HP, Perlmutter JS, Parsons SM, Tu Z. Radiosynthesis and in vivo evaluation of a novel σ 1 selective PET ligand. MEDCHEMCOMM 2014; 5:1669-1677. [PMID: 25584182 DOI: 10.1039/c4md00240g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The σ1 receptor is an important target for CNS disorders. We previously identified a σ1 ligand TZ3108 having highly potent (Ki-σ1 = 0.48 nM) and selective affinity for σ1 versus σ2 receptors. TZ3108 was 18F-labeled with F-18 for in vivo evaluation. Biodistribution and blocking studies of [18F]TZ3108 in male Sprague-Dawley rats demonstrated high brain uptake, which was σ1-specific with no in vivo defluorination. MicroPET studies in cynomolgus macaques showed high brain penetration of [18F]TZ3108; the regional brain distribution was consistent with that of the σ1 receptor. Pseudo-equilibrium in the brain was reached ~ 45 min post-injection. Metabolite analysis of [18F]TZ3108 in NHP blood and rodent blood and brain revealed that ~ 70% parent remained in the plasma of NHPs 60 min post-injection and the major radiometabolite did not cross the blood-brain barrier in rats. In summary, the potent, selective and metabolically stable σ1 specific radioligand [18F]TZ3108 represents a potentially useful PET radioligand for quantifying the σ1 receptor in the brain.
Collapse
Affiliation(s)
- Hongjun Jin
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Jinda Fan
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Xiang Zhang
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Junfeng Li
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Hubert P Flores
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Joel S Perlmutter
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA. ; Department of Neurology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Stanley M Parsons
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, 93106, USA
| | - Zhude Tu
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| |
Collapse
|
33
|
Nguyen VH, Pham T, Fookes C, Berghofer P, Greguric I, Arthur A, Mattner F, Rahardjo G, Davis E, Howell N, Gregoire MC, Katsifis A, Shepherd R. Synthesis and biological characterisation of 18F-SIG343 and 18F-SIG353, novel and high selectivity σ2 radiotracers, for tumour imaging properties. EJNMMI Res 2013; 3:80. [PMID: 24330526 PMCID: PMC3878827 DOI: 10.1186/2191-219x-3-80] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 11/21/2013] [Indexed: 12/13/2022] Open
Abstract
Background Sigma2 (σ2) receptors are highly expressed in cancer cell lines and in tumours. Two novel selective 18F-phthalimido σ2 ligands, 18F-SIG343 and 18F-SIG353, were prepared and characterised for their potential tumour imaging properties. Methods Preparation of 18F-SIG343 and 18F-SIG353 was achieved via nucleophilic substitution of their respective nitro precursors. In vitro studies including radioreceptor binding assays in the rat brain membrane and cell uptake studies in the A375 cell line were performed. In vivo studies were carried out in mice bearing A375 tumours including positron emission tomography (PET) imaging, biodistribution, blocking and metabolite studies. Results In vitro studies showed that SIG343 and SIG353 displayed excellent affinity and selectivity for σ2 receptors (Ki(σ2) = 8 and 3 nM, σ2:σ1 = 200- and 110-fold, respectively). The σ2 selectivity of 18F-SIG343 was further confirmed by blocking studies in A375 cells, however, not noted for 18F-SIG353. Biodistribution studies showed that both radiotracers had similar characteristics including moderately high tumour uptake (4%ID/g to 5%ID/g); low bone uptake (3%ID/g to 4%ID/g); and high tumour-to-muscle uptake ratios (four- to sevenfold) up to 120 min. Although radiotracer uptake in organs known to express σ receptors was significantly blocked by pre-injection of competing σ ligands, the blocking effect was not observed in the tumour. PET imaging studies indicated major radioactive localisation in the chest cavity for both ligands, with approximately 1%ID/g uptake in the tumour at 120 min. Metabolite studies showed that the original radiotracers remained unchanged 65% to 80% in the tumour up to 120 min. Conclusions The lead ligands showed promising in vitro and in vivo characteristics. However, PET imaging indicated low tumour-to-background ratios. Furthermore, we were unable to demonstrate that uptake in the A375 tumour was σ2-specific. 18F-SIG343 and 18F-SIG343 do not display ideal properties for imaging the σ2 receptor in the A375 tumour model. However, since the radiotracers show promising in vitro and in vivo characteristics, longer scans using appropriate half-life isotopes and alternative tumour models will be carried out in future studies to fully validate the imaging characteristics of these radiotracers.
Collapse
Affiliation(s)
- Vu H Nguyen
- LifeSciences, ANSTO, Locked Bag 2001, Kirrawee, New South Wales 2232, Australia.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
34
|
Li Y, Wang X, Zhang J, Deuther-Conrad W, Xie F, Zhang X, Liu J, Qiao J, Cui M, Steinbach J, Brust P, Liu B, Jia H. Synthesis and Evaluation of Novel 18F-Labeled Spirocyclic Piperidine Derivatives as σ1 Receptor Ligands for Positron Emission Tomography Imaging. J Med Chem 2013; 56:3478-91. [DOI: 10.1021/jm301734g] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Yan Li
- Key Laboratory
of Radiopharmaceuticals
(Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, People’s
Republic of China
| | - Xia Wang
- Key Laboratory
of Radiopharmaceuticals
(Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, People’s
Republic of China
| | - Jinming Zhang
- Nuclear
Medicine Department, Chinese PLA General Hospital, Beijing 100853, People’s
Republic of China
| | - Winnie Deuther-Conrad
- Helmholtz-Zentrum
Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Research
Site Leipzig, Department of Neuroradiopharmaceuticals, 04318 Leipzig,
Germany
| | - Fang Xie
- Key Laboratory
of Radiopharmaceuticals
(Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, People’s
Republic of China
| | - Xiaojun Zhang
- Nuclear
Medicine Department, Chinese PLA General Hospital, Beijing 100853, People’s
Republic of China
| | - Jian Liu
- Nuclear
Medicine Department, Chinese PLA General Hospital, Beijing 100853, People’s
Republic of China
| | - Jinping Qiao
- Key Laboratory
of Radiopharmaceuticals
(Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, People’s
Republic of China
| | - Mengchao Cui
- Key Laboratory
of Radiopharmaceuticals
(Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, People’s
Republic of China
| | - Jörg Steinbach
- Helmholtz-Zentrum
Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Research
Site Leipzig, Department of Neuroradiopharmaceuticals, 04318 Leipzig,
Germany
| | - Peter Brust
- Helmholtz-Zentrum
Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Research
Site Leipzig, Department of Neuroradiopharmaceuticals, 04318 Leipzig,
Germany
| | - Boli Liu
- Key Laboratory
of Radiopharmaceuticals
(Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, People’s
Republic of China
| | - Hongmei Jia
- Key Laboratory
of Radiopharmaceuticals
(Beijing Normal University), Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, People’s
Republic of China
| |
Collapse
|
35
|
Sakata M, Oda K, Toyohara J, Ishii K, Nariai T, Ishiwata K. Direct comparison of radiation dosimetry of six PET tracers using human whole-body imaging and murine biodistribution studies. Ann Nucl Med 2013; 27:285-96. [DOI: 10.1007/s12149-013-0685-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Accepted: 01/06/2013] [Indexed: 11/30/2022]
|
36
|
James ML, Shen B, Zavaleta CL, Nielsen CH, Mesangeau C, Vuppala PK, Chan C, Avery BA, Fishback JA, Matsumoto RR, Gambhir SS, McCurdy CR, Chin FT. New positron emission tomography (PET) radioligand for imaging σ-1 receptors in living subjects. J Med Chem 2012; 55:8272-8282. [PMID: 22853801 PMCID: PMC4106900 DOI: 10.1021/jm300371c] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
σ-1 receptor (S1R) radioligands have the potential to detect and monitor various neurological diseases. Herein we report the synthesis, radiofluorination, and evaluation of a new S1R ligand 6-(3-fluoropropyl)-3-(2-(azepan-1-yl)ethyl)benzo[d]thiazol-2(3H)-one ([(18)F]FTC-146, [(18)F]13). [(18)F]13 was synthesized by nucleophilic fluorination, affording a product with >99% radiochemical purity (RCP) and specific activity (SA) of 2.6 ± 1.2 Ci/μmol (n = 13) at end of synthesis (EOS). Positron emission tomography (PET) and ex vivo autoradiography studies of [(18)F]13 in mice showed high uptake of the radioligand in S1R rich regions of the brain. Pretreatment with 1 mg/kg haloperidol (2), nonradioactive 13, or BD1047 (18) reduced the binding of [(18)F]13 in the brain at 60 min by 80%, 82%, and 81%, respectively, suggesting that [(18)F]13 accumulation in mouse brain represents specific binding to S1Rs. These results indicate that [(18)F]13 is a promising candidate radiotracer for further evaluation as a tool for studying S1Rs in living subjects.
Collapse
Affiliation(s)
- Michelle L. James
- Molecular Imaging Program at Stanford (MIPS) Department of Radiology, Stanford University, Palo Alto CA 94305-5484, USA
| | - Bin Shen
- Molecular Imaging Program at Stanford (MIPS) Department of Radiology, Stanford University, Palo Alto CA 94305-5484, USA
| | - Cristina L. Zavaleta
- Molecular Imaging Program at Stanford (MIPS) Department of Radiology, Stanford University, Palo Alto CA 94305-5484, USA
| | - Carsten H. Nielsen
- Molecular Imaging Program at Stanford (MIPS) Department of Radiology, Stanford University, Palo Alto CA 94305-5484, USA
- Cluster for Molecular Imaging & Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of Copenhagen, Denmark
| | - Christophe Mesangeau
- Department of Medicinal Chemistry, The University of Mississippi, University, MS 38677-1848, USA
| | - Pradeep K. Vuppala
- Department of Pharmaceutics, The University of Mississippi, University, MS 38677-1848, USA
| | - Carmel Chan
- Molecular Imaging Program at Stanford (MIPS) Department of Radiology, Stanford University, Palo Alto CA 94305-5484, USA
| | - Bonnie A. Avery
- Department of Pharmaceutics, The University of Mississippi, University, MS 38677-1848, USA
| | - James A. Fishback
- Department of Basic Pharmaceutical Sciences, School of Pharmacy, West Virginia University Morgantown, WV 26506-9500, USA
| | - Rae R. Matsumoto
- Department of Basic Pharmaceutical Sciences, School of Pharmacy, West Virginia University Morgantown, WV 26506-9500, USA
| | - Sanjiv S. Gambhir
- Molecular Imaging Program at Stanford (MIPS) Department of Radiology, Stanford University, Palo Alto CA 94305-5484, USA
| | - Christopher R. McCurdy
- Department of Medicinal Chemistry, The University of Mississippi, University, MS 38677-1848, USA
| | - Frederick T. Chin
- Molecular Imaging Program at Stanford (MIPS) Department of Radiology, Stanford University, Palo Alto CA 94305-5484, USA
| |
Collapse
|
37
|
Toyohara J, Sakata M, Ishiwata K. Re-evaluation of in vivo selectivity of [11C]SA4503 to σ1 receptors in the brain: Contributions of emopamil binding protein. Nucl Med Biol 2012; 39:1049-52. [DOI: 10.1016/j.nucmedbio.2012.03.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Revised: 03/09/2012] [Accepted: 03/13/2012] [Indexed: 11/29/2022]
|
38
|
Kawamura K, Ishii S, Kobayashi T, Elsinga PH, Matsuno K, Senda M, Ishiwata K. Synthesis and evaluation of 11C-labeled SA4503, SA5845, and their ethyl derivatives as pet sigma receptor ligands. J Labelled Comp Radiopharm 2012. [DOI: 10.1002/jlcr.2580440181] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
39
|
Ishiwata K, Kobayashi T, Kawamura K, Matsuno K, Senda M. In vivo selectivity of [11C]raclopride and [11C]SA4503 for dopamine D2 receptors and sigma1 receptors, respectively. J Labelled Comp Radiopharm 2012. [DOI: 10.1002/jlcr.2580440175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
40
|
Elsinga PH, Kawamura K, Kobayashi T, Tsukada H, Senda M, Vaalburg W, Ishiwata K. Synthesis and evaluation of [18F]fluoroethyl SA4503 and SA5845 as pet-ligands for the sigma receptor. J Labelled Comp Radiopharm 2012. [DOI: 10.1002/jlcr.2580440102] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
41
|
Lever SZ, Xu R, Fan KH, Fergason-Cantrell EA, Carmack TL, Watkinson LD, Lever JR. Synthesis, radioiodination and in vitro and in vivo sigma receptor studies of N-1-allyl-N´-4-phenethylpiperazine analogs. Nucl Med Biol 2012; 39:401-14. [PMID: 22172395 DOI: 10.1016/j.nucmedbio.2011.10.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Revised: 08/25/2011] [Accepted: 10/05/2011] [Indexed: 10/14/2022]
Abstract
INTRODUCTION Sigma-1 (σ(1)) receptor radioligands are useful for basic pharmacology studies and for imaging studies in neurology, psychiatry and oncology. We derived a hybrid structure, N-1-allyl-N´-4-phenethylpiperazine, from known ligands TPCNE and SA4503 for use as a scaffold for development of radioiodinated σ(1) receptor ligands. METHODS E-and Z-N-1-(3'-iodoallyl)-N´-4-(3″,4″-dimethoxyphenethyl)-piperazine (E-1 and Z-1), N-1-allyl-N´-4-(3',4'-dimethoxyphenethyl)-piperazine (2) and E-N-1-(3'-iodoallyl)-N´-4-(3″-methoxy-4'´-hydroxyphenethyl)-piperazine (3) were synthesized. Affinities for σ(1) and σ(2) receptors were determined. [(125)I]E-1 and [(125)I]Z-1 were prepared and evaluated in vivo in mice. [(125)I]E-1 was further evaluated in σ(1) receptor binding assays in vitro. RESULTS E-1 displayed moderately high apparent affinity (15 nM) for σ(1) sites and 84-fold selectivity against σ(2) sites. Z-1 showed similar σ(1) affinity, but only 23-fold selectivity. In contrast, 2 exhibited poor binding to both subtypes, while 3 had good affinities but poor selectivity. E-1 profiled as a probable antagonist in the phenytoin shift assay. [(125)I]E-1 and [(125)I]Z-1 were prepared in good yields and with high specific radioactivities. Log D(7.4) values (2.25 and 2.27) fall within the optimal range for in vivo studies. Both radioligands selectively labeled σ(1) receptors in mouse brain and peripheral organs in vivo. [(125)I]E-1 showed a higher level of specific binding than [(125)I]Z-1 and displayed good metabolic stability. Further, [(125)I]E-1 selectively labeled σ(1) receptors in mouse brain homogenates (K(d) 3.79 nM; B(max)=599 fmol/mg protein). CONCLUSIONS [(125)I]E-1 is a selective σ(1) receptor radioligand that exhibits properties amenable to in vitro and in vivo studies, with possible extension to single photon emission computed tomography using iodine-123.
Collapse
Affiliation(s)
- Susan Z Lever
- Department of Chemistry, University of Missouri-Columbia, Columbia, MO 65211, USA.
| | | | | | | | | | | | | |
Collapse
|
42
|
Matsumoto RR, Li SM, Katz JL, Fantegrossi WE, Coop A. Effects of the selective sigma receptor ligand, 1-(2-phenethyl)piperidine oxalate (AC927), on the behavioral and toxic effects of cocaine. Drug Alcohol Depend 2011; 118:40-7. [PMID: 21420799 PMCID: PMC3662542 DOI: 10.1016/j.drugalcdep.2011.02.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2010] [Revised: 12/11/2010] [Accepted: 02/20/2011] [Indexed: 12/14/2022]
Abstract
BACKGROUND Sigma receptors represent a unique structural class of proteins and they have become increasingly studied as viable medication development targets for neurological and psychiatric disorders, including drug abuse. Earlier studies have shown that cocaine and many other abused substances interact with sigma receptors and that antagonism of these proteins can mitigate their actions. METHODS In the present study, AC927 (1-(2-phenethyl)piperidine oxalate), a selective sigma receptor ligand, was tested against the behavioral and toxic effects of cocaine in laboratory animals. RESULTS Acute administration of AC927 in male, Swiss Webster mice significantly attenuated cocaine-induced convulsions, lethality, and locomotor activity, at doses that alone had no significant effects on behavior. Subchronic administration of AC927 also attenuated cocaine-induced conditioned place preference in mice, at doses that alone had no effects on place conditioning. In drug discrimination studies in male, Sprague-Dawley rats, AC927 partially substituted for the discriminative stimulus effects of cocaine. When it was administered with cocaine, AC927 shifted the cocaine dose-response curve to the left, suggesting an enhancement of the discriminative stimulus effects of cocaine. In non-human primates, AC927 was self-administered, maintaining responding that was intermediate between contingent saline and a maintenance dose of cocaine. CONCLUSION The ability of AC927 to elicit some cocaine-like appetitive properties and to also reduce many cocaine-induced behaviors suggests that it is a promising lead for the development of a medication to treat cocaine abuse.
Collapse
Affiliation(s)
- Rae R. Matsumoto
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Oklahoma Health Sciences Center and Department of Basic Pharmaceutical Sciences, School of Pharmacy, West Virginia University,Corresponding author: Rae R. Matsumoto, Ph.D., West Virginia University, Department of Basic Pharmaceutical Sciences, School of Pharmacy, Morgantown, WV 26506. Tel.: +1 304 293 1450; fax: +1 304 293 2576.
| | - Su-Min Li
- Psychobiology Section, National Institute on Drug Abuse
| | | | - William E. Fantegrossi
- Department of Pharmacology, University of Michigan Medical School and Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences
| | - Andrew Coop
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland
| |
Collapse
|
43
|
Maisonial A, Große Maestrup E, Fischer S, Hiller A, Scheunemann M, Wiese C, Schepmann D, Steinbach J, Deuther-Conrad W, Wünsch B, Brust P. A 18F-Labeled Fluorobutyl-Substituted Spirocyclic Piperidine Derivative as a Selective Radioligand for PET Imaging of Sigma1 Receptors. ChemMedChem 2011; 6:1401-10. [DOI: 10.1002/cmdc.201100108] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Revised: 04/11/2011] [Indexed: 11/09/2022]
|
44
|
Fischer S, Wiese C, Maestrup EG, Hiller A, Deuther-Conrad W, Scheunemann M, Schepmann D, Steinbach J, Wünsch B, Brust P. Molecular imaging of σ receptors: synthesis and evaluation of the potent σ1 selective radioligand [18F]fluspidine. Eur J Nucl Med Mol Imaging 2011; 38:540-51. [PMID: 21072511 DOI: 10.1007/s00259-010-1658-z] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2010] [Accepted: 10/20/2010] [Indexed: 11/28/2022]
Abstract
PURPOSE Neuroimaging of σ(1) receptors in the human brain has been proposed for the investigation of the pathophysiology of neurodegenerative and psychiatric diseases. However, there is a lack of suitable (18)F-labelled PET radioligands for that purpose. METHODS The selective σ(1) receptor ligand [(18)F]fluspidine (1'-benzyl-3-(2-[(18)F]fluoroethyl)-3H-spiro[[2]benzofuran-1,4'-piperidine]) was synthesized by nucleophilic (18)F(-) substitution of the tosyl precursor. In vitro receptor binding affinity and selectivity were assessed by radioligand competition in tissue homogenate and autoradiographic approaches. In female CD-1 mice, in vivo properties of [(18)F]fluspidine were evaluated by ex vivo brain section imaging and organ distribution of intravenously administered radiotracer. Target specificity was validated by organ distribution of [(18)F]fluspidine after treatment with 1 mg/kg i.p. of the σ receptor antagonist haloperidol or the emopamil binding protein (EBP) inhibitor tamoxifen. In vitro metabolic stability and in vivo metabolism were investigated by LC-MS(n) and radio-HPLC analysis. RESULTS [(18)F]Fluspidine was obtained with a radiochemical yield of 35-45%, a radiochemical purity of ≥ 99.6% and a specific activity of 150-350 GBq/μmol (n = 6) within a total synthesis time of 90-120 min. In vitro, fluspidine bound specifically and with high affinity to σ(1) receptors (K (i) = 0.59 nM). In mice, [(18)F]fluspidine rapidly accumulated in brain with uptake values of 3.9 and 4.7%ID/g and brain to blood ratios of 7 and 13 at 5 and 30 min after intravenous application of the radiotracer, respectively. By ex vivo autoradiography of brain slices, resemblance between binding site occupancy of [(18)F]fluspidine and the expression of σ(1) receptors was shown. The radiotracer uptake in the brain as well as in peripheral σ(1) receptor expressing organs was significantly inhibited by haloperidol but not by tamoxifen. Incubation with rat liver microsomes led to a fast biotransformation of fluspidine. After an incubation period of 30 min only 13% of the parent compound was left. Seven metabolites were identified by HPLC-UV and LC-MS(n) techniques. However, [(18)F]fluspidine showed a higher metabolic stability in vivo. In plasma samples ∼ 94% of parent compound remained at 30 min and ∼ 67% at 60 min post-injection. Only one major radiometabolite was detected. None of the radiometabolites crossed the blood-brain barrier. CONCLUSION [(18)F]Fluspidine demonstrated favourable target affinity and specificity as well as metabolic stability both in vitro and in animal experiments. The in vivo properties of [(18)F]fluspidine offer a high potential of this radiotracer for neuroimaging and quantitation of σ(1) receptors in vivo.
Collapse
Affiliation(s)
- Steffen Fischer
- Forschungszentrum Dresden-Rossendorf, Research Site Leipzig, Institute of Radiopharmacy, Leipzig, Germany
| | | | | | | | | | | | | | | | | | | |
Collapse
|
45
|
Abstract
Sigma receptors (σ-1 and σ-2) are non-opioid proteins implicated in the pathophysiology of various neurological disorders and cancer. The σ-1 subtype is a chaperon protein widely distributed in the CNS and peripheral tissues. These receptors are involved in the modulation of K+- and Ca2+-dependent signaling cascades at the endoplasmic reticulum and modulation of neurotransmitter release. σ-1 receptors are emerging targets for the treatment of neurophychiatric diseases (schizophrenia and depression) and cocaine addiction. σ-2 receptors are lipid raft proteins. They are highly expressed on many tumor cells and hence considered potential targets for anticancer drugs. σ receptors bind to a diverse class of pharmacological compounds like cocaine, methamphetamine, benzomorphans like (±)-pentazocine, (±)-SKF-10,047 and endogenous neurosteroids and sphingolipids. In this review we focus on the early development of σ receptor-specific ligands and radiolabeling agents.
Collapse
|
46
|
Maestrup EG, Wiese C, Schepmann D, Brust P, Wünsch B. Synthesis, pharmacological activity and structure affinity relationships of spirocyclic σ(1) receptor ligands with a (2-fluoroethyl) residue in 3-position. Bioorg Med Chem 2010; 19:393-405. [PMID: 21126878 DOI: 10.1016/j.bmc.2010.11.013] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Revised: 11/03/2010] [Accepted: 11/06/2010] [Indexed: 11/30/2022]
Abstract
In order to develop a fluorinated radiotracer for imaging of σ(1) receptors in the central nervous system a series of (2-fluoroethyl) substituted spirocyclic piperidines 3 has been prepared. In the key step of the synthesis 2-bromocinnamaldehyde acetal 5 was added to piperidones 6 with various substituents at the N-atom. Unexpectedly, this reaction led to 2-benzoxepines 8, which were contracted with acid to afford the spirocyclic 2-benzofuranacetaldehydes 9. The best yields were obtained, when the transformations up to the alcohols 10 were performed without isolation of intermediates. Generally the (2-fluoroethyl) derivatives 3 have higher σ(1) affinity and σ(1)/σ(2) selectivity than the corresponding (3-fluoropropyl) derivatives 2. The most promising candidate for the development as radiotracer is the (2-fluoroethyl) derivative 3a (WMS-1828, fluspidine, 1'-benzyl-3-(2-fluoroethyl)-3H-spiro[[2]benzofuran-1,4'-piperidine]), which shows subnanomolar σ(1) affinity (K(i)=0.59nM) and excellent selectivity over the σ(2) subtype (1331-fold) as well as some other receptor systems. The novel synthetic strategy also allows the systematic pharmacological evaluation of intermediate alcohols 10. Despite their high σ(1) affinity (K(i)=6-32nM) and selectivity the alcohols 10 are 10-30-fold less potent than the bioisosteric fluoro derivatives 3.
Collapse
Affiliation(s)
- Eva Grosse Maestrup
- Institut für Pharmazeutische und Medizinische Chemie der Universität Münster, Hittorfstraße 58-62, D-48149 Münster, Germany
| | | | | | | | | |
Collapse
|
47
|
Ishiwata K, Kimura Y, Oda K, Ishii K, Sakata M, Kawasaki K, Nariai T, Suzuki Y, Ishibashi K, Mishina M, Hashimoto M, Ishikawa M, Toyohara J. Development of PET radiopharmaceuticals and their clinical applications at the Positron Medical Center. Geriatr Gerontol Int 2010; 10 Suppl 1:S180-96. [PMID: 20590833 DOI: 10.1111/j.1447-0594.2010.00594.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The Positron Medical Center has developed a large number of radiopharmaceuticals and 36 radiopharmaceuticals have been approved for clinical use for studying aging and geriatric diseases, especially brain functions. Positron emission tomography (PET) has been used to provide a highly advanced PET-based diagnosis. The current status of the development of radiopharmaceuticals, and representative clinical and methodological results are reviewed.
Collapse
Affiliation(s)
- Kiichi Ishiwata
- Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
48
|
Hajipour AR, Fontanilla D, Chu UB, Arbabian M, Ruoho AE. Synthesis and characterization of N,N-dialkyl and N-alkyl-N-aralkyl fenpropimorph-derived compounds as high affinity ligands for sigma receptors. Bioorg Med Chem 2010; 18:4397-404. [PMID: 20493718 PMCID: PMC3565575 DOI: 10.1016/j.bmc.2010.04.078] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2009] [Revised: 04/23/2010] [Accepted: 04/25/2010] [Indexed: 11/20/2022]
Abstract
The sigma-1 receptor is a unique non-opioid, non-PCP binding site that has been implicated in many different pathophysiological conditions including psychosis, drug addiction, retinal degeneration and cancer. Based on the structure of fenpropimorph, a high affinity (K(i)=0.005 nM)(1) sigma-1 receptor ligand and strong inhibitor of the yeast sterol isomerase (ERG2), we previously deduced a basic sigma-1 receptor pharmacophore or chemical backbone composed of a phenyl ring attached to a di-substituted nitrogen atom via an alkyl chain.(2) Here, we report the design and synthesis of various N,N-dialkyl or N-alkyl-N-aralkyl derivatives based on this pharmacophore as well as their binding affinities to the sigma-1 receptor. We introduce three high affinity sigma-1 receptor compounds, N,N-dibutyl-3-(4-fluorophenyl)propylamine (9), N,N-dibutyl-3-(4-nitrophenyl)propylamine (3), and N-propyl-N'-4-aminophenylethyl-3-(4-nitrophenyl)propylamine (20) with K(i) values of 17.7 nM, 0.36 nM, and 6 nM, respectively. In addition to sigma receptor affinity, we show through cytotoxicity assays that growth inhibition of various tumor cell lines occurs with our high affinity N,N-dialkyl or N-alkyl-N-aralkyl derivatives.
Collapse
Affiliation(s)
- Abdol R. Hajipour
- Department of Pharmacology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706
- Pharmaceutical Research Laboratory, Department of Chemistry, Isfahan University of Technology, Isfahan 84156, IR Iran
| | - Dominique Fontanilla
- Department of Pharmacology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706
| | - Uyen B. Chu
- Department of Pharmacology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706
| | - Marty Arbabian
- Department of Pharmacology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706
| | - Arnold E. Ruoho
- Department of Pharmacology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706
| |
Collapse
|
49
|
High occupancy of sigma1 receptors in the human brain after single oral administration of donepezil: a positron emission tomography study using [11C]SA4503. Int J Neuropsychopharmacol 2009; 12:1127-31. [PMID: 19573265 DOI: 10.1017/s1461145709990204] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The acetylcholinesterase (AChE) inhibitor donepezil is also a sigma1 receptor agonist. We examined whether donepezil binds to sigma1 receptors in the living human brain after a single oral administration. Dynamic positron emission tomography (PET) data acquisition using the selective sigma1 receptor ligand [11C]SA4503 was performed to evaluate quantitatively the binding of [11C]SA4503 to sigma1 receptors in eight healthy male volunteers. Each subject had a PET scan before and after receiving a single dose of donepezil (5 or 10 mg). The binding potential of [11C]SA4503 was calculated. Doses of 5 mg and 10 mg donepezil bound to sigma1 receptors in the human brain with occupancies of approximately 60% and approximately 75%, respectively, in a dose-dependent manner. This study demonstrated that donepezil binds to sigma1 receptors in the living human brain at therapeutic doses. Therefore, sigma1 receptors may be implicated in the pharmacological mechanism of donepezil in the human brain.
Collapse
|
50
|
Shidahara M, Seki C, Naganawa M, Sakata M, Ishikawa M, Ito H, Kanno I, Ishiwata K, Kimura Y. Improvement of likelihood estimation in Logan graphical analysis using maximum a posteriori for neuroreceptor PET imaging. Ann Nucl Med 2009; 23:163-71. [PMID: 19225940 DOI: 10.1007/s12149-008-0226-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2008] [Accepted: 11/16/2008] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To reduce variance of the total volume of distribution (V (T)) image, we improved likelihood estimation in graphical analysis (LEGA) for dynamic positron emission tomography (PET) images using maximum a posteriori (MAP). METHODS In our proposed MAP estimation in graphical analysis (MEGA), a set of time-activity curves (TACs) was formed with V (T) varying in physiological range as a template, and then the most similar TAC was sought out for a given measured TAC in a feature space. In simulation, MEGA was compared with other three methods, Logan graphical analysis (GA), multilinear analysis (MA1), and LEGA using 500 noisy TACs, under each of seven physiological conditions (from 9.9 to 61.5 of V (T)). PET studies of [(11)C]SA4503 were performed in three healthy volunteers. In clinical studies, the V (T) images estimated from MEGA were compared with region of interest (ROI) estimates from a nonlinear least square (NLS) fitting over four brain regions. RESULTS In the simulation study, the estimated V (T) by GA had a large underestimation (y = 0.27x + 8.72, r (2) = 0.87). Applying the other methods (MA1, LEGA, and MEGA), these noise-induced biases were improved (y = 0.80x + 4.04, r (2) = 0.98; y = 0.85x + 3.05, r (2) = 0.99; y = 0.96x + 1.21, r (2) = 0.99, respectively). MA1 and LEGA produced increased variance of the estimated V (T) in clinical studies. However, MEGA improved signal-to-noise ratio (SNR) in V (T) images with linear correlations between ROI estimates with NLS (y = 0.87x + 5.1, r (2) = 0.96). CONCLUSIONS MEGA was validated as an alternative strategy of LEGA to improve estimates of V (T) in clinical PET imaging.
Collapse
Affiliation(s)
- Miho Shidahara
- National Institute of Radiological Sciences, Molecular Imaging Center, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan.
| | | | | | | | | | | | | | | | | |
Collapse
|