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Wang J, Jin C, Zhou J, Zhou R, Tian M, Lee HJ, Zhang H. PET molecular imaging for pathophysiological visualization in Alzheimer's disease. Eur J Nucl Med Mol Imaging 2023; 50:765-783. [PMID: 36372804 PMCID: PMC9852140 DOI: 10.1007/s00259-022-05999-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 10/09/2022] [Indexed: 11/15/2022]
Abstract
Alzheimer's disease (AD) is the most common dementia worldwide. The exact etiology of AD is unclear as yet, and no effective treatments are currently available, making AD a tremendous burden posed on the whole society. As AD is a multifaceted and heterogeneous disease, and most biomarkers are dynamic in the course of AD, a range of biomarkers should be established to evaluate the severity and prognosis. Positron emission tomography (PET) offers a great opportunity to visualize AD from diverse perspectives by using radiolabeled agents involved in various pathophysiological processes; PET imaging technique helps to explore the pathomechanisms of AD comprehensively and find out the most appropriate biomarker in each AD phase, leading to a better evaluation of the disease. In this review, we discuss the application of PET in the course of AD and summarized radiolabeled compounds with favorable imaging characteristics.
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Affiliation(s)
- Jing Wang
- grid.412465.0Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, 310009 Zhejiang China ,grid.13402.340000 0004 1759 700XInstitute of Nuclear Medicine and Molecular Imaging of Zhejiang University, Hangzhou, 310009 Zhejiang China ,Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, 310009 Zhejiang China
| | - Chentao Jin
- grid.412465.0Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, 310009 Zhejiang China
| | - Jinyun Zhou
- grid.412465.0Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, 310009 Zhejiang China
| | - Rui Zhou
- grid.412465.0Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, 310009 Zhejiang China
| | - Mei Tian
- grid.412465.0Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, 310009 Zhejiang China ,grid.13402.340000 0004 1759 700XInstitute of Nuclear Medicine and Molecular Imaging of Zhejiang University, Hangzhou, 310009 Zhejiang China ,Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, 310009 Zhejiang China
| | - Hyeon Jeong Lee
- grid.13402.340000 0004 1759 700XCollege of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, 310014 Zhejiang China
| | - Hong Zhang
- grid.412465.0Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, 310009 Zhejiang China ,grid.13402.340000 0004 1759 700XInstitute of Nuclear Medicine and Molecular Imaging of Zhejiang University, Hangzhou, 310009 Zhejiang China ,Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, 310009 Zhejiang China ,grid.13402.340000 0004 1759 700XCollege of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, 310014 Zhejiang China ,grid.13402.340000 0004 1759 700XKey Laboratory for Biomedical Engineering of Ministry of Education, Zhejiang University, Hangzhou, 310014 Zhejiang China
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2
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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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3
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Schildt A, de Vries EFJ, Willemsen ATM, Giacobbo BL, Moraga-Amaro R, Sijbesma JWA, van Waarde A, Sossi V, Dierckx RAJO, Doorduin J. Effect of Dopamine D 2 Receptor Antagonists on [ 18F]-FEOBV Binding. Mol Pharm 2020; 17:865-872. [PMID: 32011892 PMCID: PMC7054895 DOI: 10.1021/acs.molpharmaceut.9b01129] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
The
interaction of dopaminergic and cholinergic neurotransmission
in, e.g., Parkinson’s disease has been well established. Here,
D2 receptor antagonists were used to assess changes in
[18F]-FEOBV binding to the vesicular acetylcholine transporter
(VAChT) in rodents using positron emission tomography (PET). After
pretreatment with either 10 mg/kg haloperidol, 1 mg/kg raclopride,
or vehicle, 90 min dynamic PET scans were performed with arterial
blood sampling. The net influx rate (Ki) was obtained from Patlak graphical analysis, using a metabolite-corrected
plasma input function and dynamic PET data. [18F]-FEOBV
concentration in whole-blood or plasma and the metabolite-corrected
plasma input function were not significantly changed by the pretreatments
(adjusted p > 0.07, Cohen’s d 0.28–1.89) while the area-under-the-curve (AUC) of the parent
fraction of [18F]-FEOBV was significantly higher after
haloperidol treatment (adjusted p = 0.022, Cohen’s d = 2.51) than in controls. Compared to controls, the AUC
of [18F]-FEOBV, normalized for injected dose and body weight,
was nonsignificantly increased in the striatum after haloperidol (adjusted p = 0.4, Cohen’s d = 1.77) and raclopride
(adjusted p = 0.052, Cohen’s d = 1.49) treatment, respectively. No changes in the AUC of [18F]-FEOBV were found in the cerebellum (Cohen’s d 0.63–0.74). Raclopride treatment nonsignificantly
increased Ki in the striatum 1.3-fold
compared to control rats (adjusted p = 0.1, Cohen’s d = 1.1) while it reduced Ki in the cerebellum by 28% (adjusted p = 0.0004,
Cohen’s d = 2.2) compared to control rats.
Pretreatment with haloperidol led to a nonsignificant reduction in Ki in the striatum (10%, adjusted p = 1, Cohen’s d = 0.44) and a 40–50%
lower Ki than controls in all other brain
regions (adjusted p < 0.0005, Cohen’s d = 3.3–4.7). The changes in Ki induced by the selective D2 receptor antagonist
raclopride can in part be quantified using [18F]-FEOBV
PET imaging. Haloperidol, a nonselective D2/σ receptor
antagonist, either paradoxically decreased cholinergic activity or
blocked off-target [18F]-FEOBV binding to σ receptors.
Hence, further studies evaluating the binding of [18F]-FEOBV
to σ receptors using selective σ receptor ligands are
necessary.
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Affiliation(s)
- Anna Schildt
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, 9700RB, The Netherlands.,Department of Physics and Astronomy, University of British Columbia, 143-2211 Wesbrook Mall, Vancouver, BC V6T 2B5, Canada
| | - Erik F J de Vries
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, 9700RB, The Netherlands
| | - Antoon T M Willemsen
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, 9700RB, The Netherlands
| | - Bruno Lima Giacobbo
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, 9700RB, The Netherlands
| | - Rodrigo Moraga-Amaro
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, 9700RB, The Netherlands
| | - Jürgen W A Sijbesma
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, 9700RB, The Netherlands
| | - Aren van Waarde
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, 9700RB, The Netherlands
| | - Vesna Sossi
- Department of Physics and Astronomy, University of British Columbia, 143-2211 Wesbrook Mall, Vancouver, BC V6T 2B5, Canada
| | - Rudi A J O Dierckx
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, 9700RB, The Netherlands
| | - Janine Doorduin
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, 9700RB, The Netherlands
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4
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Liu H, Luo Z, Gu J, Su Y, Flores H, Parsons SM, Zhou Y, Perlmutter JS, Tu Z. The impact of dopamine D 2-like agonist/antagonist on [ 18F]VAT PET measurement of VAChT in the brain of nonhuman primates. Eur J Pharm Sci 2020; 143:105152. [PMID: 31740395 PMCID: PMC6980745 DOI: 10.1016/j.ejps.2019.105152] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 10/15/2019] [Accepted: 11/14/2019] [Indexed: 01/11/2023]
Abstract
Vesicular acetylcholine transporter (VAChT) is a promising target for a PET measure of cholinergic deficits which contribute to cognitive impairments. Dopamine D2-like agonists and antagonists are frequently used in the elderly and could alter cholinergic function and VAChT level. Therefore, pretreatment with dopamine D2-like drugs may interfere with PET measures using [18F]VAT, a specific VAChT radioligand. Herein, we investigated the impact of dopaminergic D2-like antagonist/agonist on VAChT level in the brain of macaques using [18F]VAT PET. PET imaging studies were carried out on macaques at baseline or pretreatment conditions. For pretreatment, animals were injected using a VAChT inhibitor (-)-vesamicol, a D2-like antagonist (-)-eticlopride, and a D2-like agonist (-)-quinpirole, separately. (-)-Vesamicol was injected at escalating doses of 0.025, 0.05, 0.125, 0.25 and 0.35 mg/kg; (-)-eticlopride was injected at escalating doses of 0.01, 0.10 and 0.30 mg/kg; (-)-quinpirole was injected at escalating doses of 0.20, 0.30, and 0.50 mg/kg. PET data showed [18F]VAT uptake declined in a dose-dependent manner by (-)-vesamicol pretreatment, demonstrating [18F]VAT uptake is sensitive to reflect the availability of VAChT binding sites. Furthermore, (-)-eticlopride increased [18F]VAT striatal uptake in a dose-dependent manner, while (-)-quinpirole decreased its uptake, suggesting striatal VAChT levels can be regulated by D2-like drug administration. Our findings confirmed [18F]VAT offers a reliable tool to in vivo assess the availability of VAChT binding sites. More importantly, PET with [18F]VAT successfully quantified the impact of dopaminergic D2-like drugs on striatal VAChT level, suggesting [18F]VAT has great potential for investigating the interaction between dopaminergic and cholinergic systems in vivo.
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Affiliation(s)
- Hui Liu
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Zonghua Luo
- 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
| | - Yi Su
- 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
| | - Stanley M Parsons
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106, USA
| | - Yun Zhou
- Department of Radiology, 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; Department of Neuroscience, Physical Therapy and Occupational Therapy, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Zhude Tu
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
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5
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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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6
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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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7
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Liu H, Jin H, Luo Z, Yue X, Zhang X, Flores H, Su Y, Perlmutter JS, Tu Z. In Vivo Characterization of Two 18F-Labeled PDE10A PET Radioligands in Nonhuman Primate Brains. ACS Chem Neurosci 2018; 9:1066-1073. [PMID: 29400443 PMCID: PMC5955820 DOI: 10.1021/acschemneuro.7b00458] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Positron emission tomography (PET) with phosphodiesterase 10A (PDE10A) specific radioligands provides a noninvasive and quantitative imaging tool to access the expression of this enzyme in vivo under normal and diseased conditions. We recently reported two potent 18F-labeled PDE10A radioligands (18F-TZ19106B and 18F-TZ8110); initial evaluation in rats and nonhuman primates indicated stable metabolic profiles and excellent target-to-nontarget ratio (striatum/cerebellum) for both tracers. Herein, we focused on in vivo characterization of 18F-TZ19106B and 18F-TZ8110 to identify a suitable radioligand for imaging PDE10A in vivo. We directly compared microPET studies of these two radiotracers in adult male Macaca fascicularis nonhuman primates (NHPs). 18F-TZ19106B had higher striatal uptake and tracer retention in NHP brains than 18F-TZ8110, quantified by either standardized uptake values (SUVs) or nondisplaceable binding potential (BPND) estimated using reference-based modeling analysis. Blocking and displacement studies using the PDE10A inhibitor MP-10 indicated the binding of 18F-TZ19106B to PDE10A was specific and reversible. We also demonstrated sensitivity of 18F-TZ19106B binding to varying number of specific binding sites using escalating doses of MP-10 blockade (0.3, 0.5, 1.0, 1.5, and 2.0 mg/kg). Pretreatment with a dopamine D2-like receptor antagonist enhanced the striatal uptake of 18F-TZ19106B. Our results indicate that 18F-TZ19106B is a promising radioligand candidate for imaging PDE10A in vivo and it may be used to determine target engagement of PDE10A inhibitors and serve as a tool to evaluate the effect of novel antipsychotic therapies.
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Affiliation(s)
- Hui Liu
- Department of Radiology, Physical Therapy and Occupational Therapy, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Hongjun Jin
- Department of Radiology, Physical Therapy and Occupational Therapy, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Zonghua Luo
- Department of Radiology, Physical Therapy and Occupational Therapy, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Xuyi Yue
- Department of Radiology, Physical Therapy and Occupational Therapy, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Xiang Zhang
- Department of Radiology, Physical Therapy and Occupational Therapy, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Hubert Flores
- Department of Neurology, Physical Therapy and Occupational Therapy, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Yi Su
- Department of Radiology, Physical Therapy and Occupational Therapy, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Joel S. Perlmutter
- Department of Radiology, Physical Therapy and Occupational Therapy, Washington University School of Medicine, St. Louis, Missouri 63110, United States
- Department of Neurology, Physical Therapy and Occupational Therapy, Washington University School of Medicine, St. Louis, Missouri 63110, United States
- Department of Neuroscience, Physical Therapy and Occupational Therapy, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Zhude Tu
- Department of Radiology, Physical Therapy and Occupational Therapy, Washington University School of Medicine, St. Louis, Missouri 63110, United States
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8
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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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9
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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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10
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Han J, Liu H, Liu C, Jin H, Perlmutter JS, Egan TM, Tu Z. Pharmacologic characterizations of a P2X7 receptor-specific radioligand, [11C]GSK1482160 for neuroinflammatory response. Nucl Med Commun 2017; 38:372-382. [PMID: 28338530 PMCID: PMC5401628 DOI: 10.1097/mnm.0000000000000660] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE The P2X7 receptor (P2X7R) is a key regulatory element in the neuroinflammatory cascade that provides a promising target for imaging neuroinflammation. GSK1482160, a P2X7R modulator with nanomolar binding affinity and high selectivity, has been successfully radiolabeled and utilized for imaging P2X7 levels in a mouse model of lipopolysaccharide-induced systemic inflammation. In the current study, we further characterized its binding profile and determined whether [C]GSK1482160 can detect changes in P2X7R expression in a rodent model of multiple sclerosis. METHODS [C]GSK1482160 was synthesized with high specific activity and high radiochemical purity. Radioligand saturation and competition binding assays were performed for [C]GSK1482160 using HEK293-hP2X7R living cells. Micro-PET studies were carried out in nonhuman primates. In vitro autoradiography and immunohistochemistry studies were then carried out to evaluate tracer uptake and P2X7 expression in experimental autoimmune encephalomyelitis (EAE) rat lumbar spinal cord at EAE-peak and EAE-remitting stages compared with sham rats. RESULTS [C]GSK1482160 binds to HEK293-hP2X7R living cells with high binding affinity (Kd=5.09±0.98 nmol/l, Ki=2.63±0.6 nmol/l). Micro-PET studies showed high tracer retention and a homogeneous distribution in the brain of nonhuman primates. In the EAE rat model, tracer uptake of [C]GSK1482160 in rat lumbar spinal cord was the highest at the EAE-peak stage (277.74±79.74 PSL/mm), followed by the EAE-remitting stage(149.00±54.14 PSL/mm) and sham (66.37±1.48 PSL/mm). The tracer uptake correlated strongly with P2X7-positive cell counts, activated microglia numbers, and disease severity. CONCLUSION We conclude that [C]GSK1482160 has the potential for application in monitoring neuroinflammation.
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Affiliation(s)
- Junbin Han
- 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
| | - Chunling 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
| | - 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
| | - Terrance M. Egan
- Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Zhude Tu
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA
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11
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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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