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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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d’Orchymont F, Narvaez A, Raymond R, Sachdev P, Charil A, Krause S, Vasdev N. In vitro evaluation of PET radiotracers for imaging synaptic density, the acetylcholine transporter, AMPA-tarp-γ8 and muscarinic M4 receptors in Alzheimer's disease. AMERICAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 2024; 14:1-12. [PMID: 38500748 PMCID: PMC10944377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 02/04/2024] [Indexed: 03/20/2024]
Abstract
Several therapeutics and biomarkers that target Alzheimer's disease (AD) are under development. Our clinical positron emission tomography (PET) research programs are interested in six radiopharmaceuticals to image patients with AD and related dementias, specifically [11C]UCB-J and [18F]SynVesT-1 for synaptic vesicle glycoprotein 2A as a marker of synaptic density, two vesicular acetylcholine transporter PET radiotracers: [18F]FEOBV and [18F]VAT, as well as the transmembrane AMPA receptor regulatory protein (TARP)-γ8 tracer, [18F]JNJ-64511070, and the muscarinic acetylcholine receptor (mAChR) M4 tracer [11C]MK-6884. The goal of this study was to compare all six radiotracers (labeled with tritium or 18F) by measuring their density variability in pathologically diagnosed cases of AD, mild cognitive impairment (MCI) and normal healthy volunteer (NHV) human brains, using thin-section in vitro autoradiography (ARG). Region of interest analysis was used to quantify radioligand binding density and determine whether the radioligands provide a signal-to-noise ratio optimal for showing changes in binding. Our preliminary study confirmed that all six radiotracers show specific binding in MCI and AD. An expected decrease in their respective target density in human AD hippocampus tissues compared to NHV was observed with [3H]UCB-J, [3H]SynVesT-1, [3H]JNJ-64511070, and [3H]MK-6884. This preliminary study will be used to guide human PET imaging of SV2A, TARP-γ8 and the mAChR M4 subtype for imaging in AD and related dementias.
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Affiliation(s)
- Faustine d’Orchymont
- Azrieli Centre for Neuro-Radiochemistry, Brain Health Imaging Centre, Centre for Addiction and Mental Health (CAMH)Toronto, ON, Canada
| | - Andrea Narvaez
- Azrieli Centre for Neuro-Radiochemistry, Brain Health Imaging Centre, Centre for Addiction and Mental Health (CAMH)Toronto, ON, Canada
- Enigma Biomedical Group, Inc.Toronto, ON, Canada
| | - Roger Raymond
- Azrieli Centre for Neuro-Radiochemistry, Brain Health Imaging Centre, Centre for Addiction and Mental Health (CAMH)Toronto, ON, Canada
| | | | | | | | - Neil Vasdev
- Azrieli Centre for Neuro-Radiochemistry, Brain Health Imaging Centre, Centre for Addiction and Mental Health (CAMH)Toronto, ON, Canada
- Department of Psychiatry, University of TorontoToronto, ON, Canada
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Weinstein JJ, Moeller SJ, Perlman G, Gil R, Van Snellenberg JX, Wengler K, Meng J, Slifstein M, Abi-Dargham A. Imaging the Vesicular Acetylcholine Transporter in Schizophrenia: A Positron Emission Tomography Study Using [ 18F]-VAT. Biol Psychiatry 2024:S0006-3223(24)00062-3. [PMID: 38309322 DOI: 10.1016/j.biopsych.2024.01.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 01/10/2024] [Accepted: 01/23/2024] [Indexed: 02/05/2024]
Abstract
BACKGROUND Despite longstanding interest in the central cholinergic system in schizophrenia (SCZ), cholinergic imaging studies with patients have been limited to receptors. Here, we conducted a proof-of-concept positron emission tomography study using [18F]-VAT, a new radiotracer that targets the vesicular acetylcholine transporter as a proxy measure of acetylcholine transmission capacity, in patients with SCZ and explored relationships of vesicular acetylcholine transporter with clinical symptoms and cognition. METHODS A total of 18 adult patients with SCZ or schizoaffective disorder (the SCZ group) and 14 healthy control participants underwent a positron emission tomography scan with [18F]-VAT. Distribution volume (VT) for [18F]-VAT was derived for each region of interest, and group differences in VT were assessed with 2-sample t tests. Functional significance was explored through correlations between VT and scores on the Positive and Negative Syndrome Scale and a computerized neurocognitive battery (PennCNB). RESULTS No group differences in [18F]-VAT VT were observed. However, within the SCZ group, psychosis symptom severity was positively associated with VT in multiple regions of interest, with the strongest effects in the hippocampus, thalamus, midbrain, cerebellum, and cortex. In addition, in the SCZ group, working memory performance was negatively associated with VT in the substantia innominata and several cortical regions of interest including the dorsolateral prefrontal cortex. CONCLUSIONS In this initial study, the severity of 2 important features of SCZ-psychosis and working memory deficit-was strongly associated with [18F]-VAT VT in several cortical and subcortical regions. These correlations provide preliminary evidence of cholinergic activity involvement in SCZ and, if replicated in larger samples, could lead to a more complete mechanistic understanding of psychosis and cognitive deficits in SCZ and the development of therapeutic targets.
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Affiliation(s)
- Jodi J Weinstein
- Department of Psychiatry and Behavioral Health, Stony Brook University Renaissance School of Medicine, Stony Brook, New York; Department of Psychiatry, Columbia University Vagelos School of Medicine and New York State Psychiatric Institute, New York, New York.
| | - Scott J Moeller
- Department of Psychiatry and Behavioral Health, Stony Brook University Renaissance School of Medicine, Stony Brook, New York
| | - Greg Perlman
- Department of Psychiatry and Behavioral Health, Stony Brook University Renaissance School of Medicine, Stony Brook, New York
| | - Roberto Gil
- Department of Psychiatry and Behavioral Health, Stony Brook University Renaissance School of Medicine, Stony Brook, New York
| | - Jared X Van Snellenberg
- Department of Psychiatry and Behavioral Health, Stony Brook University Renaissance School of Medicine, Stony Brook, New York; Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York; Department of Psychology, Stony Brook University, Stony Brook, New York
| | - Kenneth Wengler
- Department of Psychiatry, Columbia University Vagelos School of Medicine and New York State Psychiatric Institute, New York, New York; Department of Radiology, Stony Brook University Renaissance School of Medicine, Stony Brook, New York
| | - Jiayan Meng
- Department of Psychiatry and Behavioral Health, Stony Brook University Renaissance School of Medicine, Stony Brook, New York
| | - Mark Slifstein
- Department of Psychiatry and Behavioral Health, Stony Brook University Renaissance School of Medicine, Stony Brook, New York
| | - Anissa Abi-Dargham
- Department of Psychiatry and Behavioral Health, Stony Brook University Renaissance School of Medicine, Stony Brook, New York; Department of Psychiatry, Columbia University Vagelos School of Medicine and New York State Psychiatric Institute, New York, New York
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Hsu CM, Lin HB, Hou XZ, Tapales RVPP, Shih CK, Miñoza S, Tsai YS, Tsai ZN, Chan CL, Liao HH. Azetidines with All-Carbon Quaternary Centers: Merging Relay Catalysis with Strain Release Functionalization. J Am Chem Soc 2023; 145:19049-19059. [PMID: 37589099 DOI: 10.1021/jacs.3c06710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/18/2023]
Abstract
Given the importance and beneficial characteristics of decorated azetidines in medicinal chemistry, efficient strategies for their synthesis are highly sought after. Herein, we report a facile synthesis of the elusive all-carbon quaternary-center-bearing azetidines. By adopting a well-orchestrated polar-radical relay strategy, ring strain release of bench-stable benzoylated 1-azabicyclo[1.1.0]butane (ABB) can be harnessed for nickel-catalyzed Suzuki Csp2-Csp3 cross-coupling with commercially available boronic acids in broad scope (>50 examples), excellent functional group tolerance, and gram-scale utility. Preliminary mechanistic studies provided insights into the underlying mechanism, wherein the ring opening of ABB with a catalytic quantity of bromide accounts for the conversion of ABB into a redox-active azetidine, which subsequently engages in the cross-coupling reaction through a radical pathway. The synergistic bromide and nickel catalysis could intriguingly be derived from a single nickel source (NiBr2). Application of the method to modify natural products, biologically relevant molecules, and pharmaceuticals has been successfully achieved as well as the synthesis of melanocortin-1 receptor (MC-1R) agonist and vesicular acetylcholine transporter (VAChT) inhibitor analogues through bioisosteric replacements of piperidine with azetidine moieties, highlighting the potential of the method in drug optimization studies. Aside from the synthesis of azetidines, we demonstrate the ancillary utility of our nickel catalytic system toward the restricted Suzuki cross-coupling of tertiary alkyl bromides with aryl boronic acids to construct all-carbon quaternary centers.
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Affiliation(s)
- Che-Ming Hsu
- Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (R.O.C.)
| | - Heng-Bo Lin
- Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (R.O.C.)
| | - Xin-Zhi Hou
- Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (R.O.C.)
| | | | - Chen-Kuei Shih
- Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (R.O.C.)
| | - Shinje Miñoza
- Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (R.O.C.)
| | - Yu-Syuan Tsai
- Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (R.O.C.)
| | - Zong-Nan Tsai
- Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (R.O.C.)
| | - Cheng-Lin Chan
- Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (R.O.C.)
| | - Hsuan-Hung Liao
- Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (R.O.C.)
- Green Hydrogen Research Center, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (R.O.C.)
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Vercouillie J, Buron F, Sérrière S, Rodrigues N, Gulhan Z, Chartier A, Chicheri G, Marzag H, Oury A, Percina N, Bodard S, Ben Othman R, Busson J, Suzenet F, Guilloteau D, Marchivie M, Emond P, Routier S, Chalon S. Development and preclinical evaluation of [18F]FBVM as a new potent PET tracer for vesicular acetylcholine transporter. Eur J Med Chem 2022; 244:114794. [DOI: 10.1016/j.ejmech.2022.114794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 09/13/2022] [Accepted: 09/23/2022] [Indexed: 11/30/2022]
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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 DOI: 10.1016/j.ejphar.2021.174556] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [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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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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8
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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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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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11
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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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12
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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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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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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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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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16
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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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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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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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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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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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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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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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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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Kozaka T, Uno I, Kitamura Y, Miwa D, Ogawa K, Shiba K. Syntheses and in vitro evaluation of decalinvesamicol analogues as potential imaging probes for vesicular acetylcholine transporter (VAChT). Bioorg Med Chem 2012; 20:4936-41. [PMID: 22831799 DOI: 10.1016/j.bmc.2012.06.040] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Revised: 06/22/2012] [Accepted: 06/22/2012] [Indexed: 02/02/2023]
Abstract
A series of vesamicol analogues, o-iodo-trans-decalinvesamicol (OIDV) or o-bromo-trans-decalinvesamicol (OBDV), were synthesized and their affinities to vesicular acetylcholine transporter (VAChT) and σ receptors (σ-1, σ-2) were evaluated by in vitro binding assays using rat cerebral or liver membranes. OIDV and OBDV showed greater binding affinity to VAChT (K(i) = 20.5 ± 5.6 and 13.8 ± 1.2 nM, respectively) than did vesamicol (K(i) = 33.9 ± 18.1 nM) with low affinity to σ receptors. A saturation binding assay in rat cerebral membranes revealed that [(125)I]OIDV had a single high affinity binding site with a K(d) value of 1.73 nM and a B(max) value of 164.4 fmol/mg protein. [(125)I]OIDV revealed little competition with inhibitors, which possessed specific affinity to each σ (σ-1 and σ-2), serotonin (5-HT(1A) and 5-HT(2A)), noradrenaline, and muscarinic acetylcholine receptors. In addition, BBB penetration of [(125)I]OIDV was verified in in vivo. The results of the binding studies indicated that OIDV and OBDV had great potential to be VAChT imaging probes with high affinity and selectivity.
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Affiliation(s)
- Takashi Kozaka
- Division of Tracer Kinetics, Advanced Science Research Center, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa 920-8640, Japan.
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Wenzel B, Li Y, Kraus W, Sorger D, Sabri O, Brust P, Steinbach J. Pyrrolovesamicols—Synthesis, structure and VAChT binding of two 4-fluorobenzoyl regioisomers. Bioorg Med Chem Lett 2012; 22:2163-6. [DOI: 10.1016/j.bmcl.2012.01.127] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Revised: 01/27/2012] [Accepted: 01/30/2012] [Indexed: 01/29/2023]
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Wang W, Cui J, Lu X, Padakanti PK, Xu J, Parsons SM, Luedtke RR, Rath NP, Tu Z. Synthesis and in vitro biological evaluation of carbonyl group-containing analogues for σ1 receptors. J Med Chem 2011; 54:5362-72. [PMID: 21732626 DOI: 10.1021/jm200203f] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
To identify the ligands for σ(1) receptors that are potent and selective, analogues of prezamicol and trozamicol scaffolds of carbonyl-containing vesicular acetylcholine transporter (VAChT) inhibitors were explored. Of the 23 analogues synthesized and tested, 5 displayed very high affinity for σ(1) (K(i) = 0.48-4.05 nM) and high selectivity for σ(1) relative to σ(2) receptors (σ(1)/σ(2) selectivity of >749-fold). Four of the five compounds (14a, 14b, 14c, and 14e) showed very low affinity for VAChT (K(i) > 290 nM), and the fifth compound (14g) showed moderate affinity for VAChT (K(i) = 44.2 nM). The compound [1'-(4-fluorobenzyl)-3'-hydroxy[1,4']bipiperidinyl-4-yl]-(4-fluorophenyl)methanone (14a) displayed very high affinity and selectivity for σ(1) receptor (K(i) = 0.48 nM, σ(1)/σ(2) > 3600). All four of these most promising compounds (14a, 14b, 14c, and 14e) can be radiosynthesized with fluorine-18 or carbon-11, which will allow further evaluation of their properties as PET probes for imaging σ(1) receptor in vivo.
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Affiliation(s)
- Wei Wang
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri 63110, United States
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