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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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2
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Myburgh PJ, Sai KKS. Development and Optimization of 11C-Labeled Radiotracers: A Review of the Modern Quality Control Design Process. ACS Pharmacol Transl Sci 2023; 6:1616-1631. [PMID: 37974626 PMCID: PMC10644505 DOI: 10.1021/acsptsci.3c00200] [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: 08/22/2023] [Indexed: 11/19/2023]
Abstract
Introduction - Several 11C-tracers have demonstrated high potential in early diagnostic PET imaging applications of neurodegenerative diseases including Alzheimer's and Parkinson's disease. These radiotracers often track critical biomarkers in disease pathogenesis such as tau fibrils ([11C]PBB3) or β-amyloid plaques ([11C]PiB) associated with such diseases. Purpose - The short review aims to serve as a guideline in the future development of radiotracers for students, postdocs and/or new radiochemists who will be synthesizing clinical grade or novel research 11C-tracers, including knowledge of regulatory requirements. We aim to bridge the gap between novel and established 11C-tracer quality control (QC) processes through exploring the design process and regulatory requirements for 11C-pharmaceuticals. Methods - A literature survey was undertaken to identify articles with a detailed description of the QC methodology and characterization for each of the sections of the review. Overview - First a general summary of 11C-tracer production was presented; this was used to establish possible places for contamination or assurances for a sterile final product. The key mandated QC analyses for clinical use were then discussed. Further, we assessed the QC methods used for established 11C-tracers and then reviewed the routine QC tests for preclinical translational and validation studies. Therefore, both mandated QC methods for clinical and preclinical animal studies were reviewed. Last, some examples of optimization and automation were reviewed, and implications of the QC practices associated with such procedures were considered. Conclusion - All of the common QC parameters associated with 11C-tracers under clinical and preclinical settings (along with a few exceptions) were discussed in detail. While it is important to establish standard, peer-reviewed QC testing protocols for a novel 11C-tracer entering the clinical umbrella, equal importance is needed on preclinical applications to address credibility and repeatability for the study.
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Affiliation(s)
- Paul Josef Myburgh
- Translational
Imaging Program, Atrium Health Wake Forest
Baptist Medical Center, Winston-Salem, North Carolina 27157, United States
| | - Kiran Kumar Solingapuram Sai
- Translational
Imaging Program, Atrium Health Wake Forest
Baptist Medical Center, Winston-Salem, North Carolina 27157, United States
- Department
of Radiology, Atrium Health Wake Forest
Baptist Medical Center, Winston-Salem, North Carolina 27157, United States
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3
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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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4
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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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Dhandabani GK, Shih CL, Wang JJ. Acid-Promoted Intramolecular Decarbonylative Coupling Reactions of Unstrained Ketones: A Modular Approach to Synthesis of Acridines and Diaryl Ketones. Org Lett 2020; 22:1955-1960. [DOI: 10.1021/acs.orglett.0c00304] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Ganesh Kumar Dhandabani
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, No. 100, Shih-Chuan first Rd, Sanmin District, Kaohsiung City, 807, Taiwan
| | - Chia-Ling Shih
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, No. 100, Shih-Chuan first Rd, Sanmin District, Kaohsiung City, 807, Taiwan
| | - Jeh-Jeng Wang
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, No. 100, Shih-Chuan first Rd, Sanmin District, Kaohsiung City, 807, Taiwan
- Department of Medical Research, Kaohsiung Medical University Hospital, No.100 Tzyou first Rd, Sanmin District, Kaohsiung City, 807, Taiwan
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6
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Discovery of 2-aminopyridines bearing a pyridone moiety as potent ALK inhibitors to overcome the crizotinib-resistant mutants. Eur J Med Chem 2019; 183:111734. [DOI: 10.1016/j.ejmech.2019.111734] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 09/22/2019] [Accepted: 09/23/2019] [Indexed: 02/03/2023]
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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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8
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Luo Z, Liu H, Jin H, Gu J, Yu Y, Kaneshige K, Perlmutter JS, Parsons SM, Tu Z. Exploration of Sulfur-Containing Analogues for Imaging Vesicular Acetylcholine Transporter in the Brain. ChemMedChem 2018; 13:1978-1987. [PMID: 30071131 PMCID: PMC6422167 DOI: 10.1002/cmdc.201800411] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2018] [Revised: 07/29/2018] [Indexed: 11/09/2022]
Abstract
Sixteen new sulfur-containing compounds targeting the vesicular acetylcholine transporter (VAChT) were synthesized and assessed for in vitro binding affinities. Enantiomers (-)-(1-(3-hydroxy-1,2,3,4-tetrahydronaphthalen-2-yl)piperidin-4-yl)(4-(methylthio)phenyl)methanone [(-)-8] and (-)-(4-((2-fluoroethyl)thio)phenyl)(1-(3-hydroxy-1,2,3,4-tetrahydronaph-thalen-2-yl)piperidin-4-yl)methanone [(-)-14 a] displayed high binding affinities, with respective Ki values of 1.4 and 2.2 nm for human VAChT, moderate and high selectivity for human VAChT over σ1 (≈13-fold) and σ2 receptors (>420-fold). Radiosyntheses of (-)-[11 C]8 and (-)-[18 F]14 a were achieved using conventional methods. Ex vivo autoradiography and biodistribution studies in Sprague-Dawley rats indicated that both radiotracers have the capacity to penetrate the blood-brain barrier, with high initial brain uptake at 5 min and rapid washout. The striatal region had the highest accumulation for both radiotracers. Pretreating the rats with the VAChT ligand (-)-vesamicol decreased brain uptake for both radiotracers. Pretreating the rats with the σ1 ligand YUN-122 (N-(4-benzylcyclohexyl)-2-(2-fluorophenyl)acetamide) also decreased brain uptake, suggesting these two radiotracers also bind to the σ1 receptor in vivo. The microPET study of (-)-[11 C]8 in the brain of a non-human primate showed high striatal accumulation that peaked quickly and washed out rapidly. Although preliminary results indicated these two sulfur-containing radiotracers have high binding affinities for VAChT with rapid washout kinetics from the striatum, their σ1 receptor binding properties limit their potential as radiotracers for quantifying VAChT in vivo.
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Affiliation(s)
- Zonghua Luo
- 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
| | - Hongjun Jin
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Jiwei Gu
- 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
| | - Kota Kaneshige
- 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, Neuroscience, Physical Therapy and Occupational Therapy, 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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9
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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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10
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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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12
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Liu F, Dawadi S, Maize KM, Dai R, Park SW, Schnappinger D, Finzel BC, Aldrich CC. Structure-Based Optimization of Pyridoxal 5'-Phosphate-Dependent Transaminase Enzyme (BioA) Inhibitors that Target Biotin Biosynthesis in Mycobacterium tuberculosis. J Med Chem 2017; 60:5507-5520. [PMID: 28594172 DOI: 10.1021/acs.jmedchem.7b00189] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The pyridoxal 5'-phosphate (PLP)-dependent transaminase BioA catalyzes the second step in the biosynthesis of biotin in Mycobacterium tuberculosis (Mtb) and is an essential enzyme for bacterial survival and persistence in vivo. A promising BioA inhibitor 6 containing an N-aryl, N'-benzoylpiperazine scaffold was previously identified by target-based whole-cell screening. Here, we explore the structure-activity relationships (SAR) through the design, synthesis, and biological evaluation of a systematic series of analogues of the original hit using a structure-based drug design strategy, which was enabled by cocrystallization of several analogues with BioA. To confirm target engagement and discern analogues with off-target activity, each compound was evaluated against wild-type (WT) Mtb in biotin-free and -containing medium as well as BioA under- and overexpressing Mtb strains. Conformationally constrained derivative 36 emerged as the most potent analogue with a KD of 76 nM against BioA and a minimum inhibitory concentration of 1.7 μM (0.6 μg/mL) against Mtb in biotin-free medium.
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Affiliation(s)
- Feng Liu
- Department of Medicinal Chemistry, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Surendra Dawadi
- Department of Medicinal Chemistry, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Kimberly M Maize
- Department of Medicinal Chemistry, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Ran Dai
- Department of Medicinal Chemistry, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Sae Woong Park
- Department of Microbiology and Immunology, Weill Cornell Medical College , New York, New York 10065, United States
| | - Dirk Schnappinger
- Department of Microbiology and Immunology, Weill Cornell Medical College , New York, New York 10065, United States
| | - Barry C Finzel
- Department of Medicinal Chemistry, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Courtney C Aldrich
- Department of Medicinal Chemistry, University of Minnesota , Minneapolis, Minnesota 55455, United States
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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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Liu H, Jin H, Yue X, Han J, Yang H, Flores H, Su Y, Alagille D, Perlmutter JS, Tamagnan G, Tu Z. Comparison of [ 11C]TZ1964B and [ 18F]MNI659 for PET imaging brain PDE10A in nonhuman primates. Pharmacol Res Perspect 2016; 4:e00253. [PMID: 27713824 PMCID: PMC5045939 DOI: 10.1002/prp2.253] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 07/21/2016] [Accepted: 07/24/2016] [Indexed: 12/26/2022] Open
Abstract
Phosphodiesterase 10A (PDE10A) inhibitors show therapeutic effects for diseases with striatal pathology. PET radiotracers have been developed to quantify in vivo PDE10A levels and target engagement for therapeutic interventions. The aim of this study was to compare two potent and selective PDE10A radiotracers, [11C]TZ1964B and [18F]MNI659 in the nonhuman primate (NHP) brain. Double scans in the same cynomolgus monkey on the same day were performed after injection of [11C]TZ1964B and [18F]MNI659. Specific uptake was determined in two ways: nondisplaceable binding potential (BPND) was calculated using cerebellum as the reference region and the PDE‐10A enriched striatum as the target region of interest (ROI); the area under the time–activity curve (AUC) for the striatum to cerebellum ratio was also calculated. High‐performance liquid chromatography (HPLC) analysis of solvent‐extracted NHP plasma identified the percentage of intact tracer versus radiolabeled metabolites samples post injection of each radiotracer. Both radiotracers showed high specific accumulation in NHP striatum. [11C]TZ1964B has higher striatal retention and lower specific striatal uptake than [18F]MNI659. The BPND estimates of [11C]TZ1964B were 3.72 by Logan Reference model (LoganREF) and 4.39 by simplified reference tissue model (SRTM); the BPND estimates for [18F]MNI659 were 5.08 (LoganREF) and 5.33 (SRTM). AUC ratios were 5.87 for [11C]TZ1964B and 7.60 for [18F]MNI659. Based on BPND values in NHP striatum, coefficients of variation were ~10% for [11C]TZ1964B and ~30% for [18F]MNI659. Moreover, the metabolism study showed the percentage of parent compounds were ~70% for [11C]TZ1964B and ~50% for [18F]MNI659 60 min post injection. These data indicate that either [11C]TZ1964B or [18F]MNI659 could serve as suitable PDE10A PET radiotracers with distinguishing features for particular clinical application.
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Affiliation(s)
- Hui Liu
- Department of Radiology Washington University School of Medicine St. Louis Missouri
| | - Hongjun Jin
- Department of Radiology Washington University School of Medicine St. Louis Missouri
| | - Xuyi Yue
- Department of Radiology Washington University School of Medicine St. Louis Missouri
| | - Junbin Han
- Department of Radiology Washington University School of Medicine St. Louis Missouri
| | - Hao Yang
- Department of Radiology Washington University School of Medicine St. Louis Missouri
| | - Hubert Flores
- Department of Neurology Washington University School of Medicine St. Louis Missouri
| | - Yi Su
- Department of Radiology Washington University School of Medicine St. Louis Missouri
| | | | - Joel S Perlmutter
- Department of Radiology Washington University School of Medicine St. Louis Missouri; Department of Neurology Washington University School of Medicine St. Louis Missouri; Department of Neuroscience Physical Therapy and Occupational Therapy Washington University School of Medicine St. Louis Missouri
| | | | - Zhude Tu
- Department of Radiology Washington University School of Medicine St. Louis Missouri
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Uno I, Kozaka T, Miwa D, Kitamura Y, Azim MAU, Ogawa K, Taki J, Kinuya S, Shiba K. In Vivo Differences between Two Optical Isomers of Radioiodinated o-iodo-trans-decalinvesamicol for Use as a Radioligand for the Vesicular Acetylcholine Transporter. PLoS One 2016; 11:e0146719. [PMID: 26752172 PMCID: PMC4713475 DOI: 10.1371/journal.pone.0146719] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 12/20/2015] [Indexed: 01/03/2023] Open
Abstract
PURPOSE To develop a superior VAChT imaging probe for SPECT, radiolabeled (-)-OIDV and (+)-OIDV were isolated and investigated for differences in their binding affinity and selectivity to VAChT, as well as their in vivo activities. PROCEDURES Radioiodinated o-iodo-trans-decalinvesamicol ([125I]OIDV) has a high binding affinity for vesicular acetylcholine transporter (VAChT) both in vitro and in vivo. Racemic [125I]OIDV was separated into its two optical isomers (-)-[125I]OIDV and (+)-[125I]OIDV by HPLC. To investigate VAChT binding affinity (Ki) of two OIDV isomers, in vitro binding assays were performed. In vivo biodistribution study of each [125I]OIDV isomer in blood, brain regions and major organs of rats was performed at 2,30 and 60 min post-injection. In vivo blocking study were performed to reveal the binding selectivity of two [125I]OIDV isomers to VAChT in vivo. Ex vivo autoradiography were performed to reveal the regional brain distribution of two [125I]OIDV isomers and (-)-[123I]OIDV for SPECT at 60 min postinjection. RESULTS VAChT binding affinity (Ki) of (-)-[125I]OIDV and (+)-[125I]OIDV was 22.1 nM and 79.0 nM, respectively. At 2 min post-injection, accumulation of (-)-[125I]OIDV was the same as that of (+)-[125I]OIDV. However, (+)-[125I]OIDV clearance from the brain was faster than (-)-[125I]OIDV. At 30 min post-injection, accumulation of (-)-[125I]OIDV (0.62 ± 0.10%ID/g) was higher than (+)-[125I]OIDV (0.46 ± 0.07%ID/g) in the cortex. Inhibition of OIDV binding showed that (-)-[125I]OIDV was selectively accumulated in regions known to express VAChT in the rat brain, and ex vivo autoradiography further confirmed these results showing similar accumulation of (-)-[125I]OIDV in these regions. Furthermore, (-)-[123I]OIDV for SPECT showed the same regional brain distribution as (-)-[125I]OIDV. CONCLUSION These results suggest that radioiodinated (-)-OIDV may be a potentially useful tool for studying presynaptic cholinergic neurons in the brain.
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Affiliation(s)
- Izumi Uno
- Division of Tracer Kinetics, Advanced Science Research Center, Kanazawa University, Ishikawa, 920-8640, Japan.,Clinical Laboratory, Kanazawa University Hospital, Kanazawa, Ishikawa, 920-8640, Japan
| | - Takashi Kozaka
- Division of Tracer Kinetics, Advanced Science Research Center, Kanazawa University, Ishikawa, 920-8640, Japan
| | - Daisuke Miwa
- Division of Tracer Kinetics, Advanced Science Research Center, Kanazawa University, Ishikawa, 920-8640, Japan.,Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Ishikawa, 920-8640, Japan
| | - Yoji Kitamura
- Division of Tracer Kinetics, Advanced Science Research Center, Kanazawa University, Ishikawa, 920-8640, Japan
| | - Mohammad Anwar-Ul Azim
- National Institute of Nuclear Medicine and Allied Sciences; Bangladesh Atomic Energy Commission, BSM Medical University Campus, Dhaka-1000, Bangladesh
| | - Kazuma Ogawa
- Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Ishikawa, 920-8640, Japan
| | - Junichi Taki
- Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Ishikawa, 920-8640, Japan
| | - Seigo Kinuya
- Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Ishikawa, 920-8640, Japan
| | - Kazuhiro Shiba
- Division of Tracer Kinetics, Advanced Science Research Center, Kanazawa University, Ishikawa, 920-8640, Japan
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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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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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18
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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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20
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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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23
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Allwood DM, Blakemore DC, Ley SV. Preparation of Unsymmetrical Ketones from Tosylhydrazones and Aromatic Aldehydes via Formyl C–H Bond Insertion. Org Lett 2014; 16:3064-7. [DOI: 10.1021/ol5011714] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Daniel M. Allwood
- Department
of Chemistry, University of Cambridge, Cambridge, CB2 1EW, U.K
| | - David C. Blakemore
- Neusentis Chemistry,
Pfizer Worldwide Research and Development, The Portway Building, Granta Park, Cambridge, CB21 6GS, U.K
| | - Steven V. Ley
- Department
of Chemistry, University of Cambridge, Cambridge, CB2 1EW, U.K
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24
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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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