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Goodchild J, Chen YJ, Blythe J, Firth LC, Hirst E, Bess K, Bristow J, Willis J, Baines R, Cash F, Muehlebach M, Buchholz A, Rendler S, Earley F, Crossthwaite A. A novel class of insecticidal alkylsulfones are potent inhibitors of vesicular acetylcholine transport. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2024; 201:105854. [PMID: 38685234 DOI: 10.1016/j.pestbp.2024.105854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 03/01/2024] [Accepted: 03/06/2024] [Indexed: 05/02/2024]
Abstract
Pyridine alkylsulfone derivatives typified by oxazosulfyl (Sumitomo Chemical Company Ltd.) and compound A2 (Syngenta) represent a new class of insecticides, with potent activity against several insect orders. Whilst the MOA of this class has been attributed to interaction with the voltage-gated sodium channel (VGSC), here we present strong evidence that their toxicity to insects is mediated primarily through inhibition of the vesicular acetylcholine transporter (VAChT). Alkylsulfone intoxication in insects is characterised by (i) a reduction in cholinergic synaptic transmission efficiency demonstrated by a depression of cercal afferent activity in giant-interneurone preparations of American cockroach (Periplaneta americana), (ii) selective block of cholinergic-transmission dependent post-synaptic potentials in the Drosophila giant-fibre pathway and (iii) abolition of miniature excitatory post-synaptic currents (mEPSCs) in an identified synapse in Drosophila larvae. Ligand-binding studies using a tritiated example compound ([3H]-A1) revealed a single saturable binding-site, with low nanomolar Kd value, in membrane fractions of green bottle fly (Lucilia sericata). Binding is inhibited by vesamicol and by several examples of a previously identified class of insecticidal compounds known to target VAChT, the spiroindolines. Displacement of this binding by analogues of the radioligand reveals a strong correlation with insecticidal potency. No specific binding was detected in untransformed PC12 cells but a PC12 line stably expressing Drosophila VAChT showed similar affinity for [3H]-A1 as that seen in fly head membrane preparations. Previously identified VAChT point mutations confer resistance to the spiroindoline class of insecticides in Drosophila by Gal-4/UAS directed expression in cholinergic neurones and by CRISPR gene-editing of VAChT, but none of these flies show detectable cross-resistance to this new chemical class. Oxazosulfyl was previously shown to stabilise voltage-gated sodium channels in their slow-inactivated conformation with an IC50 value of 12.3μM but inhibits binding of [3H]-A1 with approximately 5000 times greater potency. We believe this chemistry class represents a novel mode-of-action with high potential for invertebrate selectivity.
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Affiliation(s)
- James Goodchild
- Syngenta, Bioscience, Jealott's Hill International Research Centre, Bracknell, Berkshire RG42 6EY, UK.
| | - Ying-Ju Chen
- Syngenta, Bioscience, Jealott's Hill International Research Centre, Bracknell, Berkshire RG42 6EY, UK
| | - Judith Blythe
- Syngenta, Bioscience, Jealott's Hill International Research Centre, Bracknell, Berkshire RG42 6EY, UK
| | - Lucy C Firth
- Syngenta, Bioscience, Jealott's Hill International Research Centre, Bracknell, Berkshire RG42 6EY, UK
| | - Elizabeth Hirst
- Syngenta, Bioscience, Jealott's Hill International Research Centre, Bracknell, Berkshire RG42 6EY, UK
| | - Kirsty Bess
- Syngenta, Bioscience, Jealott's Hill International Research Centre, Bracknell, Berkshire RG42 6EY, UK
| | - Julia Bristow
- Syngenta, Bioscience, Jealott's Hill International Research Centre, Bracknell, Berkshire RG42 6EY, UK
| | - Jenny Willis
- Syngenta, Bioscience, Jealott's Hill International Research Centre, Bracknell, Berkshire RG42 6EY, UK
| | - Richard Baines
- Division of Neuroscience, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PL, UK
| | - Francesca Cash
- Division of Neuroscience, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PL, UK
| | - Michel Muehlebach
- Syngenta Crop Protection AG, Crop Protection Research, Schaffhauserstrasse 101, CH-4332 Stein, Switzerland
| | - Anke Buchholz
- Syngenta Crop Protection AG, Crop Protection Research, Schaffhauserstrasse 101, CH-4332 Stein, Switzerland
| | - Sebastian Rendler
- Syngenta Crop Protection AG, Crop Protection Research, Schaffhauserstrasse 101, CH-4332 Stein, Switzerland
| | - Fergus Earley
- Syngenta, Bioscience, Jealott's Hill International Research Centre, Bracknell, Berkshire RG42 6EY, UK
| | - Andrew Crossthwaite
- Syngenta, Bioscience, Jealott's Hill International Research Centre, Bracknell, Berkshire RG42 6EY, UK
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Bononi G, Lonzi C, Tuccinardi T, Minutolo F, Granchi C. The Benzoylpiperidine Fragment as a Privileged Structure in Medicinal Chemistry: A Comprehensive Review. Molecules 2024; 29:1930. [PMID: 38731421 PMCID: PMC11085656 DOI: 10.3390/molecules29091930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 04/08/2024] [Accepted: 04/22/2024] [Indexed: 05/13/2024] Open
Abstract
The phenyl(piperidin-4-yl)methanone fragment (here referred to as the benzoylpiperidine fragment) is a privileged structure in the development of new drugs considering its presence in many bioactive small molecules with both therapeutic (such as anti-cancer, anti-psychotic, anti-thrombotic, anti-arrhythmic, anti-tubercular, anti-parasitic, anti-diabetic, and neuroprotective agents) and diagnostic properties. The benzoylpiperidine fragment is metabolically stable, and it is also considered a potential bioisostere of the piperazine ring, thus making it a feasible and reliable chemical frame to be exploited in drug design. Herein, we discuss the main therapeutic and diagnostic agents presenting the benzoylpiperidine motif in their structure, covering articles reported in the literature since 2000. A specific section is focused on the synthetic strategies adopted to obtain this versatile chemical portion.
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Affiliation(s)
| | | | | | | | - Carlotta Granchi
- Department of Pharmacy, University of Pisa, Via Bonanno 6, 56126 Pisa, Italy; (G.B.); (C.L.); (T.T.); (F.M.)
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3
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De P, Roy K. Computational modeling of PET imaging agents for vesicular acetylcholine transporter (VAChT) protein binding affinity: application of 2D-QSAR modeling and molecular docking techniques. In Silico Pharmacol 2023; 11:9. [PMID: 37035236 PMCID: PMC10073372 DOI: 10.1007/s40203-023-00146-4] [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: 12/27/2022] [Accepted: 03/31/2023] [Indexed: 04/07/2023] Open
Abstract
The neurotransmitter acetylcholine (ACh) plays a ubiquitous role in cognitive functions including learning and memory with widespread innervation in the cortex, subcortical structures, and the cerebellum. Cholinergic receptors, transporters, or enzymes associated with many neurodegenerative diseases, including Alzheimer's disease (AD) and Parkinson's disease (PD), are potential imaging targets. In the present study, we have developed 2D-quantitative structure-activity relationship (2D-QSAR) models for 19 positron emission tomography (PET) imaging agents targeted against presynaptic vesicular acetylcholine transporter (VAChT). VAChT assists in the transport of ACh into the presynaptic storage vesicles, and it becomes one of the main targets for the diagnosis of various neurodegenerative diseases. In our work, we aimed to understand the important structural features of the PET imaging agents required for their binding with VAChT. This was done by feature selection using a Genetic Algorithm followed by the Best Subset Selection method and developing a Partial Least Squares- based 2D-QSAR model using the best feature combination. The developed QSAR model showed significant statistical performance and reliability. Using the features selected in the 2D-QSAR analysis, we have also performed similarity-based chemical read-across predictions and obtained encouraging external validation statistics. Further, we have also performed molecular docking analysis to understand the molecular interactions occurring between the PET imaging agents and the VAChT receptor. The molecular docking results were correlated with the QSAR features for a better understanding of the molecular interactions. This research serves to fulfill the experimental data gap, highlighting the applicability of computational methods in the PET imaging agents' binding affinity prediction. Graphical abstract Supplementary Information The online version contains supplementary material available at 10.1007/s40203-023-00146-4.
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Affiliation(s)
- Priyanka De
- Drug Theoretics and Cheminformatics Laboratory, Department of Pharmaceutical Technology, Jadavpur University, Kolkata, 700032 India
| | - Kunal Roy
- Drug Theoretics and Cheminformatics Laboratory, Department of Pharmaceutical Technology, Jadavpur University, Kolkata, 700032 India
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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.
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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.
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5
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Application of chiral chromatography in radiopharmaceutical fields: A review. J Chromatogr A 2020; 1632:461611. [PMID: 33086153 DOI: 10.1016/j.chroma.2020.461611] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 10/07/2020] [Accepted: 10/08/2020] [Indexed: 01/20/2023]
Abstract
Chiral column chromatography (CCC) is a revolutionary analytical methodology for the enantioseparation of novel positron emission tomography (PET) tracers in the primary stages of drug development. Due to the different behaviors of tracer enantiomers (e.g. toxicity, metabolism and side effects) in administrated subjects, their separation and purification is a challenging endeavor. Over the last three decades, different commercial chiral columns have been applied for the enantioseparation of PET-radioligand (PET-RL) or radiotracers (PET-RT), using high-performance liquid chromatography (HPLC). The categorization and reviewing of them is a vital topic. This review presents a brief overview of advances, applications, and future prospectives of CCC in radiopharmaceutical approaches. In addition, the effective chromatographic parameters and degravitation trends to enhance enantioseparation resolution are addressed. Moreover, the application and potential of chiral super fluidical chromatography (CSFC) as an alternative for enantioseparation in the field of radiopharmaceutical is discussed. Finally, the crucial application challenges of CCC are explained and imminent tasks are suggested.
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Miwa D, Kitamura Y, Kozaka T, Shigeno T, Ogawa K, Taki J, Kinuya S, Shiba K. (-)-o-[ 11 C]methyl-trans-decalinvesamicol ((-)-[ 11 C]OMDV) as a PET ligand for the vesicular acetylcholine transporter. Synapse 2020; 74:e22176. [PMID: 32500935 DOI: 10.1002/syn.22176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 05/28/2020] [Accepted: 05/28/2020] [Indexed: 11/10/2022]
Abstract
To develop a PET imaging agent to visualize brain cholinergic neurons and synaptic changes caused by Alzheimer's disease, (-)- and (+)-o-[11 C]methyl-trans-decalinvesamicol ([11 C]OMDV) were isolated and investigated for differences in not only their binding affinity and selectivity to vesicular acetylcholine transporter (VAChT), but also their in vivo activities. [11 C]OMDV has a high binding affinity for VAChT both in vitro and in vivo. Racemic OMDV and o-trimethylstannyl-trans-decalinvesamicol (OTDV), which are precursors for synthesis of [11 C]OMDV, were separated into (-)-optical isomers ((-)-OMDV and (-)-OTDV) and (+)-optical isomers ((+)-OMDV and (+)-OTDV) by HPLC. In the in vitro binding assay, (-)-OMDV(7.2 nM) showed eight times higher binding affinity (Ki) to VAChT than that of (+)-OMDV(57.5 nM). In the biodistribution study, the blood-brain barrier permeability of both enantiomers ((-)-[11 C]OMDV and (+)-[11 C]OMDV) was similarly high (about 1.0%ID/g) at 2 min post-injection. However, (+)-[11 C]OMDV clearance from the brain was faster than (-)-[11 C]OMDV. In the in vivo blocking study, accumulation of (-)-[11 C]OMDV in the cortex was markedly decreased (approximately 30% of control) by coadministration of vesamicol, and brain uptake of (-)-[11 C]OMDV was not significantly altered by coadministration of (+)-pentazocine or (+)-3-(3-hydroxyphenyl)-N-propylpiperidine ((+)-3-PPP). PET-CT imaging revealed inhibition of the rat brain uptake of (-)-[11 C]OMDV by coadministration of vesamicol. In conclusion, (-)-[11 C]OMDV, which is an enantiomer of OMDV, selectively binds to VAChT with high affinity in the rat brain in vivo. (-)-[11 C]OMDV may be utilized as a potential PET ligand for studying presynaptic cholinergic neurons in the brain.
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Affiliation(s)
- Daisuke Miwa
- Division of Tracer Kinetics, Advanced Science Research Center, Kanazawa University, Kanazawa, Japan
| | - Yoji Kitamura
- Division of Tracer Kinetics, Advanced Science Research Center, Kanazawa University, Kanazawa, Japan
| | - Takashi Kozaka
- Division of Tracer Kinetics, Advanced Science Research Center, Kanazawa University, Kanazawa, Japan
| | - Taiki Shigeno
- Division of Tracer Kinetics, Advanced Science Research Center, Kanazawa University, Kanazawa, Japan
| | - Kazuma Ogawa
- Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Japan
| | - Junichi Taki
- Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Japan
| | - Seigo Kinuya
- Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Japan
| | - Kazuhiro Shiba
- Division of Tracer Kinetics, Advanced Science Research Center, Kanazawa University, Kanazawa, Japan
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7
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Yue X, Luo Z, Liu H, Kaneshige K, Parsons SM, Perlmutter JS, Tu Z. Radiosynthesis and evaluation of a fluorine-18 labeled radioligand targeting vesicular acetylcholine transporter. Bioorg Med Chem Lett 2018; 28:3425-3430. [PMID: 30274694 DOI: 10.1016/j.bmcl.2018.09.030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 09/21/2018] [Accepted: 09/22/2018] [Indexed: 12/28/2022]
Abstract
Vesicular acetylcholine transporter (VAChT) is a reliable biomarker for assessing the loss of cholinergic neurons in the brain that is associated with cognitive impairment of patients. 5-Hydrotetralin compound (±)-5-OH-VAT is potent (Ki = 4.64 ± 0.32 nM) and selective for VAChT (>1800-fold and 398-fold for σ1 and σ2 receptor, respectively) with favorable hydrophilicity (LogD = 1.78), while (-)-5-OH-VAT originally serves as the radiolabeling precursor of (-)-[18F]VAT, a promising VAChT radiotracer with a logD value of 2.56. To evaluate (-)-5-OH-[18F]VAT as a radiotracer for VAChT, we performed in vitro binding assay to determine the potency of the minus enantiomer (-)-5-OH-VAT and plus enantiomer (+)-5-OH-VAT, indicating that (-)-5-OH-VAT is a more potent VAChT enantiomer. Radiosynthesis of (-)-5-OH-[18F]VAT was explored using three strategies. (-)-5-OH-[18F]VAT was achieved with a good yield (24 ± 6%) and high molar activity (∼37 GBq/µmol, at the end of synthesis) using a microwave assisted two-step one-pot procedure that started with di-MOM protected nitro-containing precursor (-)-6. MicroPET studies in the brain of nonhuman primate (NHP) suggest that (-)-5-OH-[18F]VAT readily penetrated the blood brain barrier and specifically accumulated in the VAChT-enriched striatum with improved washout kinetics from striatum compared to [18F]VAT. Nevertheless, the lower target to non-target ratio may limit its use for in vivo measurement of the VAChT level in the brain.
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Affiliation(s)
- Xuyi Yue
- Department of Radiology, Washington University School of Medicine, St Louis, MO 63110, United States
| | - Zonghua Luo
- Department of Radiology, Washington University School of Medicine, St Louis, MO 63110, United States
| | - Hui Liu
- Department of Radiology, Washington University School of Medicine, St Louis, MO 63110, United States
| | - Kota Kaneshige
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106, United States
| | - Stanley M Parsons
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106, United States
| | - Joel S Perlmutter
- Department of Radiology, Washington University School of Medicine, St Louis, MO 63110, United States; Department of Neurology, Washington University School of Medicine, St Louis, MO 63110, United States
| | - Zhude Tu
- Department of Radiology, Washington University School of Medicine, St Louis, MO 63110, United States.
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Roque JB, Kuroda Y, Göttemann LT, Sarpong R. Deconstructive fluorination of cyclic amines by carbon-carbon cleavage. Science 2018; 361:171-174. [PMID: 30002251 PMCID: PMC6287955 DOI: 10.1126/science.aat6365] [Citation(s) in RCA: 139] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 05/15/2018] [Indexed: 12/31/2022]
Abstract
Deconstructive functionalizations involving scission of carbon-carbon double bonds are well established. In contrast, unstrained C(sp3)-C(sp3) bond cleavage and functionalization have less precedent. Here we report the use of deconstructive fluorination to access mono- and difluorinated amine derivatives by C(sp3)-C(sp3) bond cleavage in saturated nitrogen heterocycles such as piperidines and pyrrolidines. Silver-mediated ring-opening fluorination using Selectfluor highlights a strategy for cyclic amine functionalization and late-stage skeletal diversification, establishing cyclic amines as synthons for amino alkyl radicals and providing synthetic routes to valuable building blocks.
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Affiliation(s)
- Jose B Roque
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
| | - Yusuke Kuroda
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
| | - Lucas T Göttemann
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
| | - Richmond Sarpong
- Department of Chemistry, University of California, Berkeley, CA 94720, USA.
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In Vivo and In Vitro Characteristics of Radiolabeled Vesamicol Analogs as the Vesicular Acetylcholine Transporter Imaging Agents. CONTRAST MEDIA & MOLECULAR IMAGING 2018; 2018:4535476. [PMID: 30008624 PMCID: PMC6020543 DOI: 10.1155/2018/4535476] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 04/03/2018] [Accepted: 05/02/2018] [Indexed: 12/29/2022]
Abstract
The vesicular acetylcholine transporter (VAChT), a presynaptic cholinergic neuron marker, is a potential internal molecular target for the development of an imaging agent for early diagnosis of neurodegenerative disorders with cognitive decline such as Alzheimer's disease (AD). Since vesamicol has been reported to bind to VAChT with high affinity, many vesamicol analogs have been studied as VAChT imaging agents for the diagnosis of cholinergic neurodeficit disorder. However, because many vesamicol analogs, as well as vesamicol, bound to sigma receptors (σ1 and σ2) besides VAChT, almost all the vesamicol analogs have been shown to be unsuitable for clinical trials. In this report, the relationships between the chemical structure and the biological characteristics of these developed vesamicol analogs were investigated, especially the in vitro binding profile and the in vivo regional brain accumulation.
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Jin H, Yue X, Liu H, Han J, Flores H, Su Y, Parsons SM, Perlmutter JS, Tu Z. Kinetic modeling of [ 18 F]VAT, a novel radioligand for positron emission tomography imaging vesicular acetylcholine transporter in non-human primate brain. J Neurochem 2018; 144:791-804. [PMID: 29315563 DOI: 10.1111/jnc.14291] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 12/16/2017] [Accepted: 12/19/2017] [Indexed: 01/06/2023]
Abstract
Molecular imaging of vesicular acetylcholine transporter (VAChT) in the brain provides an important cholinergic biomarker for the pathophysiology and treatment of dementias including Alzheimer's disease. In this study, kinetics modeling methods were applied and compared for quantifying regional brain uptake of the VAChT-specific positron emission tomography radiotracer, ((-)-(1-(-8-(2-fluoroethoxy)-3-hydroxy-1,2,3,4-tetrahydronaphthalen-2-yl)piperidin-4-yl)(4-fluorophenyl)-methanone) ([18 F]VAT) in macaques. Total volume distribution (VT ) estimates were compared for one-tissue compartment model (1TCM), two-tissue compartment model (2TCM), Logan graphic analysis (LoganAIF) and multiple linear analysis (MA1) with arterial blood input function using data from three macaques. Using the cerebellum-hemispheres as the reference region with data from seven macaques, three additional models were compared: reference tissue model (RTM), simplified RTM (SRTM), and Logan graphic analysis (LoganREF). Model selection criterion indicated that a) 2TCM and SRTM were the most appropriate kinetics models for [18 F]VAT; and b) SRTM was strongly correlated with 2TCM (Pearson's coefficients r > 0.93, p < 0.05). Test-retest studies demonstrated that [18 F]VAT has good reproducibility and reliability (TRV < 10%, ICC > 0.72). These studies demonstrate [18 F]VAT is a promising VAChT positron emission tomography tracer for quantitative assessment of VAChT levels in the brain of living subjects.
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Affiliation(s)
- Hongjun Jin
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Xuyi Yue
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Hui Liu
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Junbin Han
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Hubert Flores
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Yi Su
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, USA.,Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Stanley M Parsons
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California, USA
| | - Joel S Perlmutter
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, USA.,Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA.,Department of Neuroscience, Physical Therapy and Occupational Therapy, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Zhude Tu
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, USA
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11
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Yue X, Jin H, Liu H, Luo Z, Zhang X, Kaneshige K, Flores HP, Perlmutter JS, Parsons SM, Tu Z. Synthesis, resolution, and in vitro evaluation of three vesicular acetylcholine transporter ligands and evaluation of the lead fluorine-18 radioligand in a nonhuman primate. Org Biomol Chem 2018; 15:5197-5209. [PMID: 28590490 DOI: 10.1039/c7ob00854f] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The vesicular acetylcholine transporter (VAChT) is a reliable biomarker for assessing cholinergic dysfunction associated with dementia. We recently reported three new potent and selective carbon-11 labeled VAChT radiotracers. Herein, we report the resolution with a Chiralcel OD column of three additional fluorine containing VAChT ligands in which a fluoroethoxy or fluoroethylamino moiety was substituted for the methoxy group. An in vitro competitive binding assay showed that (-)-7 had high potency for VAChT (Ki-VAChT = 0.31 ± 0.03 nM) and excellent selectivity for VAChT versus σ receptors (Ki-σ1 = 1870 ± 250 nM, Ki-σ2 = 5480 ± 140 nM). Three different radiolabeling approaches were explored; the radiosynthesis of (-)-[18F]7 was successfully accomplished via a stepwise two-pot, three-step method with moderate yield (11 ± 2%) and high radiochemical purity (>98%). PET imaging studies in a nonhuman primate indicated that (-)-[18F]7 rapidly entered the brain and accumulated in the VAChT-enriched striatum. The uptake of (-)-[18F]7 in the target striatal area peaked at 10 min and displayed improved clearance kinetics compared to the VAChT tracer [18F]VAT, which has been approved by the Food and Drug Administration (FDA) for first-in-man studies. These studies justify further investigation of (-)-[18F]7 and exploration of the structure-activity relationships of these fluoroethoxy and fluoroethylamino analogs.
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Affiliation(s)
- Xuyi Yue
- Department of Radiology, Washington University School of Medicine, St Louis, MO, USA.
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Rabasa-Alcañiz F, Torres J, Sánchez-Roselló M, Tejero T, Merino P, Fustero S, del Pozo C. Organocatalytic Enantioselective Synthesis of Trifluoromethyl-Containing Tetralin Derivatives by Sequential (Hetero)Michael Reaction-Intramolecular Nitrone Cycloaddition. Adv Synth Catal 2017. [DOI: 10.1002/adsc.201700975] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
| | - Javier Torres
- Departamento de Química Orgánica; Universidad de Valencia; 46100 Burjassot Spain
| | | | - Tomás Tejero
- Instituto de Síntesis Química y Catálisis Homogénea (ISQCH); Universidad de Zaragoza; 50009 Zaragoza Spain
| | - Pedro Merino
- Instituto de Biocomputación y Fisica de Sistemas Complejos (BIFI); Universidad de Zaragoza; 50009 Zaragoza Spain
| | - Santos Fustero
- Departamento de Química Orgánica; Universidad de Valencia; 46100 Burjassot Spain
- Laboratorio de Moléculas Orgánicas; Centro de Investigación Príncipe Felipe; 46012 Valencia Spain
| | - Carlos del Pozo
- Departamento de Química Orgánica; Universidad de Valencia; 46100 Burjassot Spain
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13
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Roslin S, De Rosa M, Deuther-Conrad W, Eriksson J, Odell LR, Antoni G, Brust P, Larhed M. Synthesis and in vitro evaluation of 5-substituted benzovesamicol analogs containing N-substituted amides as potential positron emission tomography tracers for the vesicular acetylcholine transporter. Bioorg Med Chem 2017; 25:5095-5106. [PMID: 28185725 DOI: 10.1016/j.bmc.2017.01.041] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 01/19/2017] [Accepted: 01/23/2017] [Indexed: 12/17/2022]
Abstract
Herein, new ligands for the vesicular acetylcholine transporter (VAChT), based on a benzovesamicol scaffold, are presented. VAChT is acknowledged as a marker for cholinergic neurons and a positron emission tomography tracer for VAChT could serve as a tool for quantitative analysis of cholinergic neuronal density. With an easily accessible triflate precursor, aminocarbonylations were utilized to evaluate the chemical space around the C5 position on the tetrahydronaphthol ring. Synthesized ligands were evaluated for their affinity and selectivity for VAChT. Small, preferably aromatic, N-substituents proved to be more potent than larger substituents. Of the fifteen compounds synthesized, benzyl derivatives (±)-7i and (±)-7l had the highest affinities for VAChT. Compound (±)-7i was chosen to investigate the importance of stereochemistry for binding to VAChT and selectivity toward the σ1 and σ2 receptors. Enantiomeric resolution gave (+)-7i and (-)-7i, and the eutomer showed seven times better affinity. Although racemate (±)-7i was initially promising, the affinity of (-)-7i for VAChT was not better than 56.7nM which precludes further preclinical evaluation. However, the nanomolar binding together with the ready synthesis of [11C]-(±)-7i shows that (-)-7i can serve as a scaffold for future optimizations to provide improved 11C-labelled VAChT PET tracers.
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Affiliation(s)
- Sara Roslin
- Organic Pharmaceutical Chemistry, Department of Medicinal Chemistry, Uppsala University, BMC Box 574, SE-751 23 Uppsala, Sweden
| | - Maria De Rosa
- Organic Pharmaceutical Chemistry, Department of Medicinal Chemistry, Uppsala University, BMC Box 574, SE-751 23 Uppsala, Sweden
| | - Winnie Deuther-Conrad
- Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, Research Site Leipzig, 04318 Leipzig, Germany
| | - Jonas Eriksson
- Organic Pharmaceutical Chemistry, Department of Medicinal Chemistry, Uppsala University, BMC Box 574, SE-751 23 Uppsala, Sweden
| | - Luke R Odell
- Organic Pharmaceutical Chemistry, Department of Medicinal Chemistry, Uppsala University, BMC Box 574, SE-751 23 Uppsala, Sweden
| | - Gunnar Antoni
- Organic Pharmaceutical Chemistry, Department of Medicinal Chemistry, Uppsala University, BMC Box 574, SE-751 23 Uppsala, Sweden
| | - Peter Brust
- Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, Research Site Leipzig, 04318 Leipzig, Germany
| | - Mats Larhed
- Science for Life Laboratory, Department of Medicinal Chemistry, Uppsala University, BMC Box 574, SE-751 23 Uppsala, Sweden.
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14
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Karimi M, Tu Z, Yue X, Zhang X, Jin H, Perlmutter JS, Laforest R. Radiation dosimetry of [(18)F]VAT in nonhuman primates. EJNMMI Res 2015; 5:73. [PMID: 26660544 PMCID: PMC4675760 DOI: 10.1186/s13550-015-0149-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 11/26/2015] [Indexed: 11/16/2022] Open
Abstract
Background The objective of this study is to determine the radiation dosimetry of a novel radiotracer for vesicular acetylcholine transporter (−)-(1-((2R,3R)-8-(2-[18F]fluoro-ethoxy)-3-hydroxy-1,2,3,4-tetrahydronaphthalen-2-yl)piperidin-4-yl)(4-fluorophenyl)-methanone ([18F]VAT) based on PET imaging in nonhuman primates. [18F]VAT has potential for investigation of neurological disorders including Alzheimer’s disease, Parkinson’s disease, and dystonia. Methods Three macaque fascicularis (two males, one female) received 185.4–198.3 MBq [18F]VAT prior to whole-body imaging in a MicroPET-F220 scanner. Time activity curves (TACs) were created from regions of interest (ROIs) that encompassed the entire small organs or samples with the highest activity within large organs. Organ residence times were calculated based on the TACs. We then used OLINDA/EXM 1.1 to calculate human radiation dose estimates based on scaled organ residence times. Results Measurements from directly sampled arterial blood yielded a residence time of 0.30 h in agreement with the residence time of 0.39 h calculated from a PET-generated time activity curve measured in the left ventricle. Organ dosimetry revealed the liver as the critical organ (51.1 and 65.4 μGy/MBq) and an effective dose of 16 and 19 μSv/MBq for male and female, respectively. Conclusions The macaque biodistribution data showed high retention of [18F]VAT in the liver consistent with hepatobiliary clearance. These dosimetry data support that relatively safe doses of [18F]VAT can be administered to obtain imaging in humans.
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Affiliation(s)
- Morvarid Karimi
- Department of Neurology, Washington University Medical School, St. Louis, MO, 63110, USA.
| | - Zhude Tu
- Mallinckrodt Institute of Radiology, Washington University Medical School, St. Louis, MO, USA.
| | - Xuyi Yue
- Mallinckrodt Institute of Radiology, Washington University Medical School, St. Louis, MO, USA.
| | - Xiang Zhang
- Mallinckrodt Institute of Radiology, Washington University Medical School, St. Louis, MO, USA.
| | - Hongjun Jin
- Mallinckrodt Institute of Radiology, Washington University Medical School, St. Louis, MO, USA.
| | - Joel S Perlmutter
- Department of Neurology, Washington University Medical School, St. Louis, MO, 63110, USA. .,Mallinckrodt Institute of Radiology, Washington University Medical School, St. Louis, MO, USA. .,Department of Neurobiology, Washington University Medical School, St. Louis, MO, USA. .,Department of Physical Therapy, Washington University Medical School, St. Louis, MO, USA. .,Department of Occupational Therapy, Washington University Medical School, St. Louis, MO, USA.
| | - Richard Laforest
- Mallinckrodt Institute of Radiology, Washington University Medical School, St. Louis, MO, USA.
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15
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Jin H, Zhang X, Yue X, Liu H, Li J, Yang H, Flores H, Su Y, Parsons SM, Perlmutter JS, Tu Z. Kinetics modeling and occupancy studies of a novel C-11 PET tracer for VAChT in nonhuman primates. Nucl Med Biol 2015; 43:131-9. [PMID: 26872437 DOI: 10.1016/j.nucmedbio.2015.11.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2015] [Revised: 10/29/2015] [Accepted: 11/05/2015] [Indexed: 01/18/2023]
Abstract
INTRODUCTION Deficits in cholinergic function have been found in the aged brain and in neurodegenerative diseases including Alzheimer's disease (AD) and Parkinson's disease (PD). The vesicular acetylcholine transporter (VAChT) is a reliable biomarker for the cholinergic system. We previously reported the initial in vitro and ex vivo characterization of (-)-[(11)C]TZ659 as a VAChT specific ligand. Here, we report the in vivo specificity, tracer kinetics, and dose-occupancy studies in the nonhuman primate brain. METHODS MicroPET brain imaging of (-)-[(11)C]TZ659 was performed under baseline conditions in two male macaques. Tracer kinetic modeling was carried out using a two-tissue compartment model (2TCM) and Logan plot with arterial blood input function and using a simplified reference tissue model (SRTM) and Logan plot (LoganREF) without blood input. Specificity for VAChT was demonstrated by pretreatment with (+)-pentazocine, (-)-vesamicol, or S-(-)-eticlopride. Target occupancy (Occ) was calculated following pretreatment with escalating doses of (-)-vesamicol. RESULTS Baseline PET imaging revealed selective retention in the striatum with rapid clearance from the cerebellar hemispheres as a reference region. Total volume of distribution (VT) values derived from both 2TCM and Logan analysis with blood input revealed ~3-fold higher levels of (-)-[(11)C]TZ659 in the striatum than the cerebellar hemispheres. Injection of (-)-vesamicol either as a blocking or displacing agent significantly reduced striatal uptake of (-)-[(11)C]TZ659. In contrast, pretreatment with the sigma-1 ligand (+)-pentazocine had no impact. Pretreatment with the S-(-)-eticlopride, a dopamine D2-like receptor antagonist, increased striatal uptake of (-)-[(11)C]TZ659. Striatal binding potential (BPND, range of 0.33-1.6 with cerebellar hemispheres as the reference region) showed good correlation (r(2)=0.97) between SRTM and LoganREF. Occupancy studies found that ~0.0057 mg/kg of (-)-vesamicol produced 50% VAChT occupancy in the striatum. CONCLUSION (-)-[(11)C]TZ659 demonstrated specific and reversible VAChT binding and favorable pharmacokinetic properties for assessing the density of VAChT in the living brain.
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Affiliation(s)
- Hongjun Jin
- 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
| | - Xuyi Yue
- 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
| | - Junfeng Li
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Hao Yang
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Hubert Flores
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Yi Su
- 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
| | - 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
| | - Zhude Tu
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
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16
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Deau E, Robin E, Voinea R, Percina N, Satała G, Finaru AL, Chartier A, Tamagnan G, Alagille D, Bojarski AJ, Morisset-Lopez S, Suzenet F, Guillaumet G. Rational Design, Pharmacomodulation, and Synthesis of Dual 5-Hydroxytryptamine 7 (5-HT7)/5-Hydroxytryptamine 2A (5-HT2A) Receptor Antagonists and Evaluation by [18F]-PET Imaging in a Primate Brain. J Med Chem 2015; 58:8066-96. [DOI: 10.1021/acs.jmedchem.5b00874] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Emmanuel Deau
- Institut
de Chimie Organique et Analytique (ICOA), Université d’Orléans, CNRS, UMR 7311, rue de Chartres, F-45067 Orleans, France
| | - Elodie Robin
- Centre
de Biophysique Moléculaire, Centre National de la Recherche Scientifique (CNRS), UPR 4301, Université d’Orléans et INSERM, rue Charles Sadron, 45071 Orléans Cedex 2, France
| | - Raluca Voinea
- Institut
de Chimie Organique et Analytique (ICOA), Université d’Orléans, CNRS, UMR 7311, rue de Chartres, F-45067 Orleans, France
- Centrul
de Cercetare ‘Chimie Aplicată şi Inginerie de
Proces’, Universitatea din Bacău, Calea Mărăşesti,
nr. 157, 600115 Bacău, Romania
| | - Nathalie Percina
- Institut
de Chimie Organique et Analytique (ICOA), Université d’Orléans, CNRS, UMR 7311, rue de Chartres, F-45067 Orleans, France
| | - Grzegorz Satała
- Institute of Pharmacology, Polish Academy of Sciences, 12 Smętna
Street, Kraków 31-343, Poland
| | - Adriana-Luminita Finaru
- Centrul
de Cercetare ‘Chimie Aplicată şi Inginerie de
Proces’, Universitatea din Bacău, Calea Mărăşesti,
nr. 157, 600115 Bacău, Romania
| | - Agnès Chartier
- Institut
de Chimie Organique et Analytique (ICOA), Université d’Orléans, CNRS, UMR 7311, rue de Chartres, F-45067 Orleans, France
| | - Gilles Tamagnan
- Molecular NeuroImaging, 60 Temple
Street, New Haven, Connecticut 06510, United States
| | - David Alagille
- Molecular NeuroImaging, 60 Temple
Street, New Haven, Connecticut 06510, United States
| | - Andrzej J. Bojarski
- Institute of Pharmacology, Polish Academy of Sciences, 12 Smętna
Street, Kraków 31-343, Poland
| | - Séverine Morisset-Lopez
- Centre
de Biophysique Moléculaire, Centre National de la Recherche Scientifique (CNRS), UPR 4301, Université d’Orléans et INSERM, rue Charles Sadron, 45071 Orléans Cedex 2, France
| | - Franck Suzenet
- Institut
de Chimie Organique et Analytique (ICOA), Université d’Orléans, CNRS, UMR 7311, rue de Chartres, F-45067 Orleans, France
| | - Gérald Guillaumet
- Institut
de Chimie Organique et Analytique (ICOA), Université d’Orléans, CNRS, UMR 7311, rue de Chartres, F-45067 Orleans, France
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17
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Automated production of [¹⁸F]VAT suitable for clinical PET study of vesicular acetylcholine transporter. Appl Radiat Isot 2015; 107:40-46. [PMID: 26408913 DOI: 10.1016/j.apradiso.2015.09.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2015] [Revised: 08/07/2015] [Accepted: 09/07/2015] [Indexed: 11/20/2022]
Abstract
Automated production of a promising radiopharmaceutical (-)-(1-(8-(2-[(18)F]fluoroethoxy)-3-hydroxy-1,2,3,4-tetrahydronaphthalen-2-yl)-piperidin-4-yl)(4-fluorophenyl)methanone ([(18)F]VAT) for the vesicular acetylcholine transporter(VAChT) was achieved using a two-step procedure in a current Good Manufacturing Practices fashion. The production of [(18)F]VAT was accomplished in approximately 140 min, with radiochemical yield of ~15.0% (decay corrected), specific activity>111 GBq/µmol, radiochemical purity>99% and mass of VAT ~3.4 μg/batch (n>10). The radiopharmaceutical product meets all quality control criteria for human use, and is suitable for clinical PET studies of VAChT.
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18
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Padakanti PK, Zhang X, Li J, Parsons SM, Perlmutter JS, Tu Z. Syntheses and radiosyntheses of two carbon-11 labeled potent and selective radioligands for imaging vesicular acetylcholine transporter. Mol Imaging Biol 2015; 16:765-72. [PMID: 24875230 DOI: 10.1007/s11307-014-0748-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
PURPOSE The vesicular acetylcholine transporter (VAChT) is a specific biomarker for imaging presynaptic cholinergic neurons. The syntheses and C-11 labeling of two potent enantiopure VAChT inhibitors are reported here. PROCEDURES Two VAChT inhibitors, (±)-2 and (±)-6, were successfully synthesized. A chiral HPLC column was used to resolve the enantiomers from each corresponding racemic mixture for in vitro characterization. The radiosyntheses of (-)-[(11)C]2 and (-)-[(11)C]6 from the corresponding desmethyl phenol precursor was accomplished using [(11)C]methyl iodide or [(11)C]methyl triflate, respectively. RESULTS The synthesis of (-)-[(11)C]2 was accomplished with 40-50 % radiochemical yield (decay-corrected), SA > 480 GBq/μmol (EOB), and radiochemical purity >99 %. Synthesis of (-)-[(11)C]6 was accomplished with 5-10 % yield, SA > 140 GBq/μmol (EOB), and radiochemical purity >97 %. The radiosynthesis and dose formulation of each tracer was completed in 55-60 min. CONCLUSIONS Two potent enantiopure VAChT ligands were synthesized and (11)C-labeled with good radiochemical yield and specific activity.
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Affiliation(s)
- Prashanth K Padakanti
- Department of Radiology, Washington University School of Medicine, 510 South Kingshighway Blvd, St. Louis, MO, 63110, USA
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19
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In vitro and in vivo characterization of two C-11-labeled pet tracers for vesicular acetylcholine transporter. Mol Imaging Biol 2015; 16:773-80. [PMID: 24865402 DOI: 10.1007/s11307-014-0749-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
PURPOSE The vesicular acetylcholine transporter (VAChT) is a specific biomarker for imaging presynaptic cholinergic neurons. Herein, two potent and selective (11)C-labeled VAChT inhibitors were evaluated in rodents and nonhuman primates for imaging VAChT in vivo. PROCEDURES For both (-)-[(11)C]2 and (-)-[(11)C]6, biodistribution, autoradiography, and metabolism studies were performed in male Sprague Dawley rats. Positron emission tomography (PET) brain studies with (-)-[(11)C]2 were performed in adult male cynomolgus macaques; 2 h dynamic data was acquired, and the regions of interest were drawn by co-registration of the PET images with the MRI. RESULTS The resolved enantiomers (-)-2 and (-)-6 were very potent and selective for VAChT in vitro (K i < 5 nM for VAChT with >35-fold selectivity for VAChT vs. σ receptors); both radioligands, (-)-[(11)C]2 and (-)-[(11)C]6, demonstrated high accumulation in the VAChT-enriched striatum of rats. (-)-[(11)C]2 had a higher striatum to cerebellum ratio of 2.4-fold at 60 min; at 30 min, striatal uptake reached 0.550 ± 0.086 %ID/g. Uptake was also specific and selective; following pretreatment with (±)-2, striatal uptake of (-)-[(11)C]2 in rats at 30 min decreased by 50 %, while pretreatment with a potent sigma ligand had no significant effect on striatal uptake in rats. In addition, (-)-[(11)C]2 displayed favorable in vivo stability in rat blood and brain. PET studies of (-)-[(11)C]2 in nonhuman primates indicate that it readily crosses the blood-brain barrier (BBB) and provides clear visualization of the striatum; striatal uptake reaches the maximum at 60 min, at which time the target to nontarget ratio reached ~2-fold. CONCLUSIONS The radioligand (-)-[(11)C]2 has high potential to be a suitable PET radioligand for imaging VAChT in the brain of living subjects.
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20
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Barthel C, Sorger D, Deuther-Conrad W, Scheunemann M, Schweiger S, Jäckel P, Roghani A, Steinbach J, Schüürmann G, Sabri O, Brust P, Wenzel B. New systematically modified vesamicol analogs and their affinity and selectivity for the vesicular acetylcholine transporter – A critical examination of the lead structure. Eur J Med Chem 2015; 100:50-67. [DOI: 10.1016/j.ejmech.2015.05.033] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 05/20/2015] [Accepted: 05/21/2015] [Indexed: 12/14/2022]
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21
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Tu Z, Zhang X, Jin H, Yue X, Padakanti PK, Yu L, Liu H, Flores HP, Kaneshige K, Parsons SM, Perlmutter JS. Synthesis and biological characterization of a promising F-18 PET tracer for vesicular acetylcholine transporter. Bioorg Med Chem 2015; 23:4699-4709. [PMID: 26138195 DOI: 10.1016/j.bmc.2015.05.058] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 05/22/2015] [Accepted: 05/28/2015] [Indexed: 12/14/2022]
Abstract
Nine fluorine-containing vesicular acetylcholine transporter (VAChT) inhibitors were synthesized and screened as potential PET tracers for imaging the VAChT. Compound 18a was one of the most promising carbonyl-containing benzovesamicol analogs; the minus enantiomer, (-)-18a displayed high potency (VAChT Ki=0.59 ± 0.06 nM) and high selectivity for VAChT versus σ receptors (>10,000-fold). The radiosynthesis of (-)-[(18)F]18a was accomplished by a two-step procedure with 30-40% radiochemical yield. Preliminary biodistribution studies of (-)-[(18)F]18a in adult male Sprague-Dawley rats at 5, 30, 60 and 120 min post-injection (p.i.) were promising. The total brain uptake of (-)-[(18)F]18a was 0.684%ID/g at 5 min p.i. and by 120 min p.i. slowly washed out to 0.409 %ID/g; evaluation of regional brain uptake showed stable levels of ∼0.800 %ID/g from 5 to 120 min p.i in the VAChT-enriched striatal tissue of rats, indicating the tracer had crossed the blood brain barrier and was retained in the striatum. Subsequent microPET brain imaging studies of (-)-[(18)F]18a in nonhuman primates (NHPs) showed high striatal accumulation in the NHP brain; the standardized uptake value (SUV) for striatum reached a maximum value of 5.1 at 15 min p.i. The time-activity curve for the target striatal region displayed a slow and gradual decreasing trend 15 min after injection, while clearance of the radioactivity from the cerebellar reference region was much more rapid. Pretreatment of NHPs with 0.25mg/kg of the VAChT inhibitor (-)-vesamicol resulted in a ∼90% decrease of striatal uptake compared to baseline studies. HPLC metabolite analysis of NHP plasma revealed that (-)-[(18)F]18a had a good in vivo stability. Together, these preliminary results suggest (-)-[(18)F]18a is a promising PET tracer candidate for imaging VAChT in the brain of living subjects.
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Affiliation(s)
- Zhude Tu
- Department of Radiology, Washington University School of Medicine, 510 South Kingshighway Blvd., St. Louis, MO 63110, USA.
| | - Xiang Zhang
- Department of Radiology, Washington University School of Medicine, 510 South Kingshighway Blvd., St. Louis, MO 63110, USA
| | - Hongjun Jin
- Department of Radiology, Washington University School of Medicine, 510 South Kingshighway Blvd., St. Louis, MO 63110, USA
| | - Xuyi Yue
- Department of Radiology, Washington University School of Medicine, 510 South Kingshighway Blvd., St. Louis, MO 63110, USA
| | - Prashanth K Padakanti
- Department of Radiology, Washington University School of Medicine, 510 South Kingshighway Blvd., St. Louis, MO 63110, USA
| | - Lihai Yu
- Department of Radiology, Washington University School of Medicine, 510 South Kingshighway Blvd., St. Louis, MO 63110, USA
| | - Hui Liu
- Department of Radiology, Washington University School of Medicine, 510 South Kingshighway Blvd., St. Louis, MO 63110, USA
| | - Hubert P Flores
- Department of Neurology, Washington University School of Medicine, 510 South Kingshighway Blvd., St. Louis, MO 63110, USA
| | - Kota Kaneshige
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106, USA
| | - Stanley M Parsons
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106, USA
| | - Joel S Perlmutter
- Department of Radiology, Washington University School of Medicine, 510 South Kingshighway Blvd., St. Louis, MO 63110, USA; Department of Neurology, Washington University School of Medicine, 510 South Kingshighway Blvd., St. Louis, MO 63110, USA
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22
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Liu H, Jin H, Li J, Zhang X, Kaneshige K, Parsons SM, Perlmutter JS, Tu Z. In vitro and ex vivo characterization of (-)-TZ659 as a ligand for imaging the vesicular acetylcholine transporter. Eur J Pharmacol 2015; 752:18-25. [PMID: 25678250 PMCID: PMC4369186 DOI: 10.1016/j.ejphar.2015.02.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 01/30/2015] [Accepted: 02/03/2015] [Indexed: 12/30/2022]
Abstract
The loss of cholinergic neurons and synapses relates to the severity of dementia in several neurodegenerative pathologies; and the vesicular acetylcholine transporter (VAChT) provides a reliable biomarker of cholinergic function. We recently characterized and (11)C-labeled a new VAChT inhibitor, (-)-TZ659. Here we report the in vitro and ex vivo characterization of (-)-TZ659. A stably transfected PC12(A123.7) cell line which expresses human VAChT (hVAChT) was used for the in vitro binding characterization of (-)-[(3)H]TZ659. A saturated binding curve was obtained with Kd=1.97±0.30nM and Bmax=3240±145.9fmol/mg protein. In comparison, a PC12(A123.7) cell line that expresses mutant hVAChT showed decreased binding affinity (Kd=15.94±0.28nM). Competitive binding assays using a panel of other CNS ligands showed no inhibition of (-)-[(3)H]TZ659 binding. On the other hand, binding inhibitions were observed only using VAChT inhibitors (Ki=0.20-31.35nM). An in vitro assay using rat brain homogenates showed that (-)-[(3)H]TZ659 had higher binding in striatum than in cerebellum, with a target: non-target ratio>3.46. Even higher ex vivo striatum-to-cerebellum ratios (9.56±1.11) were observed using filtered homogenates of brain tissue after rats were injected intravenously with (-)-[(11)C]TZ659. Ex vivo autoradiography of (-)-[(11)C]TZ659 confirmed high striatal uptake, with a consistently high striatum-to-cerebellum ratio (2.99±0.44). In conclusion, (-)-TZ659 demonstrated high potency and good specificity for VAChT in vitro and in vivo. These data suggest that (-)-[(11)C]TZ659 may be a promising PET tracer to image VAChT in the brain.
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Affiliation(s)
- Hui Liu
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Hongjun Jin
- 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
| | - Xiang Zhang
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Kota Kaneshige
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106, USA
| | - Stanley M Parsons
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106, 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
| | - Zhude Tu
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
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Kilbourn MR. PET radioligands for the vesicular transporters for monoamines and acetylcholine. J Labelled Comp Radiopharm 2014; 56:167-71. [PMID: 24285322 DOI: 10.1002/jlcr.2998] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 06/15/2012] [Accepted: 11/06/2012] [Indexed: 11/09/2022]
Abstract
The vesicular transporters for the monoamine and acetylcholine have been successfully targeted for the development of radioligands for human brain imaging. The vesicular monoamine transporter type 2 ligands are based on the structure of tetrabenazine, a known clinically used drug. In contrast, the radioligands for vesicular acetylcholine transporter are based on vesamicol, a toxic xenobiotic. The similarities and differences in the development of these two classes of radioligands are discussed.
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Affiliation(s)
- Michael R Kilbourn
- Division of Nuclear Medicine, Department of Radiology, University of Michigan Medical School, Ann Arbor, MI, USA
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24
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Azim MAU, Kozaka T, Uno I, Miwa D, Kitamura Y, Ogawa K, Makino A, Kiyono Y, Shiba K. The potential ofo-bromo-trans-decalinvesamicol as a new PET ligand for vesicular acetylcholine transporter imaging. Synapse 2014; 68:445-53. [DOI: 10.1002/syn.21756] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 05/28/2014] [Accepted: 06/14/2014] [Indexed: 12/31/2022]
Affiliation(s)
- Mohammad Anwar-ul Azim
- Division of Tracer Kinetics; Advanced Science Research Center, Kanazawa University; 13-1 Takara-machi Kanazawa Ishikawa 920-8640 Japan
- Graduate School of Natural Science and Technology; Kanazawa University; Kakuma 920-1192 Japan
| | - Takashi Kozaka
- Division of Tracer Kinetics; Advanced Science Research Center, Kanazawa University; 13-1 Takara-machi Kanazawa Ishikawa 920-8640 Japan
- College of Medical; Pharmaceutical and Health Sciences, 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
- College of Medical; Pharmaceutical and Health Sciences, 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
- College of Medical; Pharmaceutical and Health Sciences, Kanazawa University; 13-1 Takara-machi Kanazawa Ishikawa 920-8640 Japan
| | - Yoji Kitamura
- Division of Tracer Kinetics; Advanced Science Research Center, Kanazawa University; 13-1 Takara-machi Kanazawa Ishikawa 920-8640 Japan
- Graduate School of Natural Science and Technology; Kanazawa University; Kakuma 920-1192 Japan
- College of Medical; Pharmaceutical and Health Sciences, Kanazawa University; 13-1 Takara-machi Kanazawa Ishikawa 920-8640 Japan
| | - Kazuma Ogawa
- College of Medical; Pharmaceutical and Health Sciences, Kanazawa University; 13-1 Takara-machi Kanazawa Ishikawa 920-8640 Japan
| | - Akira Makino
- Biomedical Imaging Research Center; University of Fukui, 23-3 Matsuokashimoaizuki, Eiheiji-cho, Yoshida-gun; Fukui Prefecture 910-1193 Japan
| | - Yasushi Kiyono
- Biomedical Imaging Research Center; University of Fukui, 23-3 Matsuokashimoaizuki, Eiheiji-cho, Yoshida-gun; Fukui Prefecture 910-1193 Japan
| | - Kazuhiro Shiba
- Division of Tracer Kinetics; Advanced Science Research Center, Kanazawa University; 13-1 Takara-machi Kanazawa Ishikawa 920-8640 Japan
- Graduate School of Natural Science and Technology; Kanazawa University; Kakuma 920-1192 Japan
- College of Medical; Pharmaceutical and Health Sciences, Kanazawa University; 13-1 Takara-machi Kanazawa Ishikawa 920-8640 Japan
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25
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Bergman S, Estrada S, Hall H, Rahman R, Blomgren A, Larhed M, Svedberg M, Thibblin A, Wångsell F, Antoni G. Synthesis and labeling of a piperazine-based library of11C-labeled ligands for imaging of the vesicular acetylcholine transporter. J Labelled Comp Radiopharm 2014; 57:525-32. [DOI: 10.1002/jlcr.3208] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 04/24/2014] [Accepted: 04/25/2014] [Indexed: 01/08/2023]
Affiliation(s)
- Sara Bergman
- Preclinical PET Platform, Department of Medicinal Chemistry; Uppsala University; Box 574 SE-751 23 Uppsala Sweden
| | - Sergio Estrada
- Preclinical PET Platform, Department of Medicinal Chemistry; Uppsala University; Box 574 SE-751 23 Uppsala Sweden
| | - Håkan Hall
- Preclinical PET Platform, Department of Medicinal Chemistry; Uppsala University; Box 574 SE-751 23 Uppsala Sweden
| | - Rashidur Rahman
- Preclinical PET Platform, Department of Medicinal Chemistry; Uppsala University; Box 574 SE-751 23 Uppsala Sweden
| | - Andreas Blomgren
- Organic Pharmaceutical Chemistry, Department of Medicinal Chemistry; Uppsala University; BMC Box 574 SE-751 23 Uppsala Sweden
| | - Mats Larhed
- Science for Life Laboratory, Department of Medicinal Chemistry; Uppsala University; BMC Box 574 SE-751 23 Uppsala Sweden
| | - Marie Svedberg
- Preclinical PET Platform, Department of Medicinal Chemistry; Uppsala University; Box 574 SE-751 23 Uppsala Sweden
| | - Alf Thibblin
- Preclinical PET Platform, Department of Medicinal Chemistry; Uppsala University; Box 574 SE-751 23 Uppsala Sweden
| | - Fredrik Wångsell
- Organic Pharmaceutical Chemistry, Department of Medicinal Chemistry; Uppsala University; BMC Box 574 SE-751 23 Uppsala Sweden
| | - Gunnar Antoni
- Preclinical PET Platform, Department of Medicinal Chemistry; Uppsala University; Box 574 SE-751 23 Uppsala Sweden
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26
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Nishiyama S, Ohba H, Kobashi T, Nakamasu Y, Nakao H, Ogata T, Kitashoji T, Tsukada H. Development of novel PET probe [¹¹C](R,R)HAPT and its stereoisomer [¹¹C](S,S)HAPT for vesicular acetylcholine transporter imaging: a PET study in conscious monkey. Synapse 2014; 68:283-92. [PMID: 24687885 DOI: 10.1002/syn.21743] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Revised: 03/19/2014] [Accepted: 03/24/2014] [Indexed: 12/17/2022]
Abstract
Carbon-11-labeled (R,R)trans-8-methyl-2-hydroxy-3-[4-[2-aminophenyl]piperizinyl]-tetralin ([(11)C](R,R)HAPT) and its stereoisomer [(11)C](S,S)HAPT were developed for imaging vesicular acetylcholine transporters (VAChTs), exclusively located in presynaptic cholinergic neurons. Both positron emission tomography (PET) probes were evaluated in the brain of conscious monkey (Macaca mulatta) using high-resolution PET. Time-activity curves (TACs) of [(11)C](R,R)HAPT peaked within 5 min after the injection in all regions except the caudate and putamen, both of which showed peaks around 20 min postinjection. The regional distribution patterns of [(11)C](R,R)HAPT determined as total distribution volume (V(t)) were highest in the putamen, high in the caudate, intermediate in the amygdala, hippocampus, and thalamus, lower in the cingulate gyrus and frontal, temporal, and occipital cortices, and lowest in the cerebellum. In contrast, the distribution and TACs of [(11)C](S,S)HAPT were homogeneous in all regions. The uptake of [(11)C](R,R)HAPT was reduced by 1 mg/kg (-)-vesamicol, a specific VAChT antagonist, in all regions except the cerebellum, but not by 0.1 mg/kg SA4503, a specific sigma-1 receptor agonist. These results well reflect the in vitro affinity assessments using rat cerebral membranes. They also demonstrate that [(11)C](R,R)HAPT is a potential PET probe for noninvasive and quantitative imaging of VAChT in the living brain.
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Affiliation(s)
- Shingo Nishiyama
- Central Research Laboratory, Hamamatsu Photonics K.K., Hamakita, Hamamatsu, Shizuoka, Japan
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27
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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.
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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
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28
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Wenzel B, Günther R, Brust P, Steinbach J. A fluoro versus a nitro derivative-a high-performance liquid chromatography study of two basic analytes with different reversed phases and silica phases as basis for the separation of a positron emission tomography radiotracer. J Chromatogr A 2013; 1311:98-105. [PMID: 24021831 DOI: 10.1016/j.chroma.2013.08.068] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Revised: 08/15/2013] [Accepted: 08/17/2013] [Indexed: 02/05/2023]
Abstract
To develop a basis for the separation of a (18)F-labeled PET radiotracer from its nitro precursor, we performed an analytical HPLC study using the unlabeled reference compound and the corresponding nitro precursor. Aim of the study was to find a separation in which the fluoro derivative elutes in front of the nitro precursor with appropriate separation parameters. Several RP phases as well as a bare silica column were investigated with ACN and MeOH as organic modifiers and aqueous NH4OAc because of the basic character of the analytes. Four types of separation were observed based on different interaction mechanisms. When ACN/20mM NH4OAc aq. was used mainly cationic-exchange and hydrophobic interactions contributed to the retention. A reversal of elution order could be observed starting from 95% ACN and subsequent increasing of the water content. This phenomenon was observed for all RP phases and seems to be independent of the different spacers bound to the silica. By contrast, using MeOH/20mM NH4OAc aq. the elution order depends on the phase material. Two columns with the potential to perform π-π interactions showed different separation behavior compared to the other RP phases.
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Affiliation(s)
- Barbara Wenzel
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research (former Institute of Radiopharmacy), Research Site Leipzig, Dept. of Neuroradiopharmaceuticals, Germany.
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29
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Li J, Zhang X, Zhang Z, Padakanti PK, Jin H, Cui J, Li A, Zeng D, Rath NP, Flores H, Perlmutter JS, Parsons SM, Tu Z. Heteroaromatic and aniline derivatives of piperidines as potent ligands for vesicular acetylcholine transporter. J Med Chem 2013; 56:6216-33. [PMID: 23802889 DOI: 10.1021/jm400664x] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
To identify suitable lipophilic compounds having high potency and selectivity for vesicular acetylcholine transporter (VAChT), a heteroaromatic ring or a phenyl group was introduced into the carbonyl-containing scaffold for VAChT ligands. Twenty new compounds with ALogD values between 0.53 and 3.2 were synthesized, and their in vitro binding affinities were assayed. Six of them (19a, 19e, 19g, 19k, and 24a-b) displayed high affinity for VAChT (Ki = 0.93-18 nM for racemates) and moderate to high selectivity for VAChT over σ1 and σ2 receptors (Ki = 44-4400-fold). These compounds have a methyl or a fluoro substitution that provides the position for incorporating PET radioisotopes C-11 or F-18. Compound (-)-[(11)C]24b (Ki = 0.78 nM for VAChT, 1200-fold over σ receptors) was successfully synthesized and evaluated in vivo in rats and nonhuman primates. The data revealed that (-)-[(11)C]24b has highest binding in striatum and has favorable pharmacokinetics in the brain.
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Affiliation(s)
- Junfeng Li
- Department of Radiology, Washington University School of Medicine, 510 South Kingshighway Boulevard, St. Louis, MO 63110, USA
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30
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Abstract
Acetylcholine, the first chemical to be identified as a neurotransmitter, is packed in synaptic vesicles by the activity of VAChT (vesicular acetylcholine transporter). A decrease in VAChT expression has been reported in a number of diseases, and this has consequences for the amount of acetylcholine loaded in synaptic vesicles as well as for neurotransmitter release. Several genetically modified mice targeting the VAChT gene have been generated, providing novel models to understand how changes in VAChT affect transmitter release. A surprising finding is that most cholinergic neurons in the brain also can express a second type of vesicular neurotransmitter transporter that allows these neurons to secrete two distinct neurotransmitters. Thus a given neuron can use two neurotransmitters to regulate different physiological functions. In addition, recent data indicate that non-neuronal cells can also express the machinery used to synthesize and release acetylcholine. Some of these cells rely on VAChT to secrete acetylcholine with potential physiological consequences in the periphery. Hence novel functions for the oldest neurotransmitter known are emerging with the potential to provide new targets for the treatment of several pathological conditions.
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31
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A 96-well filtration method for radioligand binding analysis of σ receptor ligands. J Pharm Biomed Anal 2012; 71:157-61. [PMID: 22910107 DOI: 10.1016/j.jpba.2012.07.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 07/18/2012] [Accepted: 07/22/2012] [Indexed: 11/24/2022]
Abstract
σ receptors represent a potential drug target for numerous therapeutic indications including cancer, depression, psychostimulant abuse, and stroke. Most published radioligand binding studies for σ receptors utilize a low throughput method employing a "cell harvester." Higher throughput methods are required to facilitate efficient screening of large numbers of novel compounds. In this study, a series of reference compounds was analyzed with a new medium-throughput 96-well filtration method and the results were compared to those obtained using the conventional cell harvester-based method. The 96-well assay utilized rat liver membranes for the determination of both known σ receptor subtypes (σ(1) and σ(2)) because this tissue contains high densities of both subtypes and fulfills criteria required for reliable use with the 96-well format. The new method gave comparable K(i) values for reference ligands analyzed in parallel with samples prepared in rat brain membranes and processed on the traditional cell harvester. For σ(1) receptors, equivalent affinity values were observed for both methods/tissues. For σ(2) receptors, approximately 2-fold higher affinities were observed for most compounds in liver, as compared to brain membranes, but excellent correlation with brain-derived values was maintained. To further demonstrate the utility of the new method it was used to screen a novel series of 2(3H)-benzothiazolone compounds, resulting in the identification of several analogues with nanomolar affinity and greater than 50-fold specificity for σ(1) versus σ(2) receptors.
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32
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Tu Z, Wang W, Cui J, Zhang X, Lu X, Xu J, Parsons SM. Synthesis and evaluation of in vitro bioactivity for vesicular acetylcholine transporter inhibitors containing two carbonyl groups. Bioorg Med Chem 2012; 20:4422-9. [PMID: 22739089 PMCID: PMC3389281 DOI: 10.1016/j.bmc.2012.05.045] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Revised: 05/08/2012] [Accepted: 05/15/2012] [Indexed: 01/17/2023]
Abstract
To identify selective high-affinity ligands for the vesicular acetylcholine transporter (VAChT), we have incorporated a carbonyl group into the structures of trozamicol and prezamicol scaffolds, and also converted the secondary amines of the piperidines of trozamicols and prezamicols into amides. Of 18 new racemic compounds, 4 compounds displayed high affinity for VAChT (K(i)=10-20 nM) and greater than 300-fold selectivity for VAChT over σ(1) and σ(2) receptors, namely (4-(4-fluorobenzoyl)-4'-hydroxy-[1,3'-bipiperidin]-1'-yl)(3-methylthiophen-2-yl)methanone oxalate (9g) (K(i-VAChT)=11.4 nM, VAChT/σ(1)=1063, VAChT/σ(2)=370), (1'-benzoyl-4'-hydroxy-[1,3'-bipiperidin]-4-yl)(4-methoxyphenyl)methanone oxalate (10c) (K(i-VAChT)=15.4 nM, VAChT/σ(1)=374, VAChT/σ(2)=315), (4'-hydroxy-1'-(thiophene-2-carbonyl)-[1,3'-bipiperidin]-4-yl)(4-methoxyphenyl)methanone oxalate (10e) (K(i-VAChT)=19.0 nM, VAChT/σ(1)=1787, VAChT/σ(2)=335), and (4'-hydroxy-1'-(3-methylthiophene-2-carbonyl)-[1,3'-bipiperidin]-4-yl)(4-methoxyphenyl)methanone oxalate (10g) (K(i-VAChT)=10.2 nM, VAChT/σ(1)=1500, VAChT/σ(2)=2030). These four compounds can be radiosynthesized with C-11 or F-18 to validate their possibilities of serving as PET probes for quantifying the levels of VAChT in vivo.
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Affiliation(s)
- Zhude Tu
- Department of Radiology, Washington University, St. Louis, MO 63110, United States.
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33
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Wenzel B, Hiller A, Fischer S, Sorger D, Deuther-Conrad W, Scheunemann M, Brust P, Sabri O, Steinbach J. In vitro binding profile and radiosynthesis of a novel 18F-labeled azaspirovesamicol analog as potential ligand for imaging of the vesicular acetylcholine transporter. J Labelled Comp Radiopharm 2011. [DOI: 10.1002/jlcr.1891] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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34
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Nguyen TH, Abarbri M, Guilloteau D, Mavel S, Emond P. Nucleophilic fluorination of alkynyliodonium salts by alkali metal fluorides: access to fluorovinylic compounds. Tetrahedron 2011. [DOI: 10.1016/j.tet.2011.03.043] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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35
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Wenzel B, Fischer S, Brust P, Steinbach J. Accessible silanol sites – Beneficial for the RP-HPLC separation of constitutional and diastereomeric azaspirovesamicol isomers. J Chromatogr A 2010; 1217:7884-90. [DOI: 10.1016/j.chroma.2010.10.061] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Revised: 10/08/2010] [Accepted: 10/14/2010] [Indexed: 11/29/2022]
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36
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Khare P, Mulakaluri A, Parsons SM. Search for the acetylcholine and vesamicol binding sites in vesicular acetylcholine transporter: the region around the lumenal end of the transport channel. J Neurochem 2010; 115:984-93. [PMID: 20831599 DOI: 10.1111/j.1471-4159.2010.06990.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Vesicular acetylcholine transporter (VAChT; TC 2.A.1.2.13) mediates storage of acetylcholine (ACh) by synaptic vesicles. A three-dimensional homology model of VAChT is available, but the binding sites for ACh and the allosteric inhibitor (-)-trans-2-(4-phenylpiperidino)cyclohexanol (vesamicol) are unknown. In previous work, mutations of invariant W331 in the lumenal beginning of transmembrane helix VIII (TM VIII) of rat VAChT led to as much as ninefold loss in equilibrium affinity for ACh and no loss in affinity for vesamicol. The current work investigates the effects of additional mutations in and around W331 and the nearby lumenal end of the substrate transport channel. Mutants of human VAChT were expressed in the PC12(A123.7) cell line and characterized using radiolabeled ligands and filtration assays for binding and transport. Properties of a new and a repeat mutation in W331 are consistent with the original observations. Of 16 additional mutations in 13 other residues (Y60 in the beginning of lumenal Loop I/II, F231 in the lumenal end of TM V, W315, M316, K317, in the lumenal end of TM VII, M320, A321, W325, A330 in lumenal Loop VII/VIII, A334 in the lumenal beginning of TM VIII, and C388, C391, F392 in the lumenal beginning of TM X), only A334F impairs binding. This mutation decreases ACh and vesamicol equilibrium binding affinities by 14- and 4-fold, respectively. The current results, combined with previous results, demonstrate existence of a spatial cluster of residues close to vesicular lumen that decreases affinity for ACh and/or vesamicol when the cluster is mutated. The cluster is composed of invariant W331, highly conserved A334, and invariant F335 in TM VIII and invariant C391 in TM X. Different models for the locations of the ACh and vesamicol binding sites relative to this cluster are discussed.
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Affiliation(s)
- Parul Khare
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106-9510, USA
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37
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Xie K, Wang S, Li P, Li X, Yang Z, An X, Guo CC, Tan Z. Synthesis of tetralin and chromane derivatives via In-catalyzed intramolecular hydroarylation. Tetrahedron Lett 2010. [DOI: 10.1016/j.tetlet.2010.06.091] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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38
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Wenzel B, Fischer S, Brust P, Steinbach J. Enantioseparation of vesamicol and novel vesamicol analogs by high-performance liquid chromatography on different chiral stationary phases. J Chromatogr A 2010; 1217:3855-62. [DOI: 10.1016/j.chroma.2010.04.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Revised: 03/30/2010] [Accepted: 04/12/2010] [Indexed: 11/24/2022]
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39
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Efange SMN, Khare AB, von Hohenberg K, Mach RH, Parsons SM, Tu Z. Synthesis and in vitro biological evaluation of carbonyl group-containing inhibitors of vesicular acetylcholine transporter. J Med Chem 2010; 53:2825-35. [PMID: 20218624 DOI: 10.1021/jm9017916] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
To identify selective high-affinity inhibitors of the vesicular acetylcholine transporter (VAChT), we have interposed a carbonyl group between the phenyl and piperidyl groups of the prototypical VAChT ligand vesamicol and its more potent analogues benzovesamicol and 5-aminobenzovesamicol. Of 33 compounds synthesized and tested, 6 display very high affinity for VAChT (K(i), 0.25-0.66 nM) and greater than 500-fold selectivity for VAChT over sigma(1) and sigma(2) receptors. Twelve compounds have high affinity (K(i), 1.0-10 nM) and good selectivity for VAChT. Furthermore, 3 halogenated compounds, namely, trans-3-[4-(4-fluorobenzoyl)piperidinyl]-2-hydroxy-1,2,3,4-tetrahydronaphthalene (28b) (K(i) = 2.7 nM, VAChT/sigma selectivity index = 70), trans-3-[4-(5-iodothienylcarbonyl)piperidinyl]-2-hydroxy-1,2,3,4-tetrahydronaphthalene (28h) (K(i) = 0.66 nM, VAChT/sigma selectivity index = 294), and 5-amino-3-[4-(p-fluorobenzoyl)piperidinyl]-2-hydroxy-1,2,3,4,-tetrahydronaphthalene (30b) (K(i) = 2.40 nM, VAChT/sigma selectivity index = 410) display moderate to high selectivity for VAChT. These three compounds can be synthesized with the corresponding radioisotopes so as to serve as PET/SPECT probes for imaging the VAChT in vivo.
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Affiliation(s)
- Simon M N Efange
- Departments of Radiology, Medicinal Chemistry and Neurosurgery, University of Minnesota, Minneapolis, Minnesota 55455, USA
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40
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Localisation of pre- and postsynaptic cholinergic markers in the human brain. Behav Brain Res 2010; 221:341-55. [PMID: 20170687 DOI: 10.1016/j.bbr.2010.02.025] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Accepted: 02/10/2010] [Indexed: 12/20/2022]
Abstract
The cholinergic neurotransmission in the central nervous system plays an important role in modulating cognitive processes such as learning, memory, arousal and sleep as well as in modulating locomotor activity. Dysfunction of the central cholinergic system is involved in numerous neuropsychiatric diseases. This review will provide a synopsis on the regional localisation of cholinergic and cholinoceptive structures within the adult human brain. On the cholinergic site data based on the distribution of choline acetyltransferase-immunoreactive structures are in the focus, complemented by data from acetylcholinesterase and vesicular acetylcholine transporter studies. On the cholinoceptive site, the distribution and localisation of receptors that transduce the acetylcholine message, i.e. the muscarinic and the nicotinic acetylcholine receptors is summarized. In addition to these data obtained on post mortem brain an overview of markers which allow for the in vivo monitoring of the cholinergic system in the brain is given. The detailed knowledge on the distribution and localisation of cholinergic markers in human brain will provide further information on the cholinergic circuits of neurotransmission - a prerequisite for the interpretation of in vivo imaging data and the development of selective diagnostic and therapeutic compounds.
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Khare P, White AR, Parsons SM. Multiple protonation states of vesicular acetylcholine transporter detected by binding of [3H]vesamicol. Biochemistry 2009; 48:8965-75. [PMID: 19685929 DOI: 10.1021/bi900759v] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Vesicular acetylcholine transporter (VAChT) is inhibited by (-)-vesamicol [(-)-trans-2-(4-phenylpiperidino)cyclohexanol], which binds tightly to an allosteric site. The tertiary alkylamine center in (-)-vesamicol is protonated and positively charged at acidic and neutral pH and unprotonated and uncharged at alkaline pH. Deprotonation of the amine has been taken to explain loss of (-)-vesamicol binding at alkaline pH. However, binding data deviate from a stereotypical bell shape, and more binding occurs than expected at alkaline pH. The current study characterizes the binding of (-)-vesamicol from pH 5 to pH 10 using filter assays, (-)-[3H]vesamicol (hereafter called [3H]vesamicol), and human VAChT expressed in PC12(A123.7) cells. At acidic pH, protons and [3H]vesamicol compete for binding to VAChT. Preexposure or long-term exposure of VAChT to high pH does not affect binding, thus eliminating potential denaturation of VAChT and failure of the filter assay. The dissociation constant for the complex between protonated [3H]vesamicol and VAChT decreases from 12 nM at neutral pH to 2.1 nM at pH 10. The simplest model of VAChT that explains the behavior requires a proton at site 1 to dissociate with pK1 = 6.5 +/- 0.1, a proton at site A to dissociate with pKA = 7.6 +/- 0.2, and a proton at site B to dissociate with pKB = 10.0 +/- 0.1. Deprotonation of the site 1 proton is obligatory for [3H]vesamicol binding. Deprotonation of site A decreases affinity (2.2 +/- 0.5)-fold, and deprotonation of site B increases affinity (18 +/- 4)-fold. Time-dependent dissociation of bound [3H]vesamicol is biphasic, but equilibrium saturation curves are not. The contrasting phasicity suggests that the pathway to and from the [3H]vesamicol binding site exists in open and at least partially closed states. The potential significance of the findings to development of PET and SPECT ligands based on (-)-vesamicol for human diagnostics also is discussed.
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Affiliation(s)
- Parul Khare
- Department of Chemistry and Biochemistry, Neuroscience Research Institute, University of California, Santa Barbara, California 93106, USA
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