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Niu J, Zhong Y, Jin C, Cen P, Wang J, Cui C, Xue L, Cui X, Tian M, Zhang H. Positron Emission Tomography Imaging of Synaptic Dysfunction in Parkinson's Disease. Neurosci Bull 2024; 40:743-758. [PMID: 38483697 PMCID: PMC11178751 DOI: 10.1007/s12264-024-01188-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 12/09/2023] [Indexed: 06/15/2024] Open
Abstract
Parkinson's disease (PD) is one of the most common neurodegenerative diseases with a complex pathogenesis. Aggregations formed by abnormal deposition of alpha-synuclein (αSyn) lead to synapse dysfunction of the dopamine and non-dopamine systems. The loss of dopaminergic neurons and concomitant alterations in non-dopaminergic function in PD constitute its primary pathological manifestation. Positron emission tomography (PET), as a representative molecular imaging technique, enables the non-invasive visualization, characterization, and quantification of biological processes at cellular and molecular levels. Imaging synaptic function with PET would provide insights into the mechanisms underlying PD and facilitate the optimization of clinical management. In this review, we focus on the synaptic dysfunction associated with the αSyn pathology of PD, summarize various related targets and radiopharmaceuticals, and discuss applications and perspectives of PET imaging of synaptic dysfunction in PD.
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Affiliation(s)
- Jiaqi Niu
- Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, 310009, China
- Institute of Nuclear Medicine and Molecular Imaging, Zhejiang University, Hangzhou, 310009, China
- Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, 310009, China
| | - Yan Zhong
- Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, 310009, China
- Institute of Nuclear Medicine and Molecular Imaging, Zhejiang University, Hangzhou, 310009, China
- Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, 310009, China
| | - Chentao Jin
- Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, 310009, China
- Institute of Nuclear Medicine and Molecular Imaging, Zhejiang University, Hangzhou, 310009, China
- Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, 310009, China
| | - Peili Cen
- Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, 310009, China
- Institute of Nuclear Medicine and Molecular Imaging, Zhejiang University, Hangzhou, 310009, China
- Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, 310009, China
| | - Jing Wang
- Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, 310009, China
- Institute of Nuclear Medicine and Molecular Imaging, Zhejiang University, Hangzhou, 310009, China
- Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, 310009, China
| | - Chunyi Cui
- Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, 310009, China
- Institute of Nuclear Medicine and Molecular Imaging, Zhejiang University, Hangzhou, 310009, China
- Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, 310009, China
| | - Le Xue
- Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, 310009, China
- Institute of Nuclear Medicine and Molecular Imaging, Zhejiang University, Hangzhou, 310009, China
- Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, 310009, China
| | - Xingyue Cui
- Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, 310009, China
- Institute of Nuclear Medicine and Molecular Imaging, Zhejiang University, Hangzhou, 310009, China
- Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, 310009, China
| | - Mei Tian
- Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, 310009, China.
- Institute of Nuclear Medicine and Molecular Imaging, Zhejiang University, Hangzhou, 310009, China.
- Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, 310009, China.
- Huashan Hospital and Human Phenome Institute, Fudan University, Shanghai, 200040, China.
| | - Hong Zhang
- Department of Nuclear Medicine and PET Center, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, 310009, China.
- Institute of Nuclear Medicine and Molecular Imaging, Zhejiang University, Hangzhou, 310009, China.
- Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou, 310009, China.
- College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, 310014, China.
- Key Laboratory for Biomedical Engineering of Ministry of Education, Zhejiang University, Hangzhou, 310014, China.
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Li X, Chen Z, Tang J, Liu C, Zou P, Huang H, Tan C, Yu H. Synthesis and biological evaluation of 10-(11) C-dihydrotetrabenazine as a vesicular monoamine transporter 2 radioligand. Arch Pharm (Weinheim) 2014; 347:313-9. [PMID: 24497196 DOI: 10.1002/ardp.201300307] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 11/14/2013] [Accepted: 11/15/2013] [Indexed: 11/06/2022]
Abstract
In this study, we synthesized a new carbon-11-labeled radiotracer, 10-(11) C-dihydrotetrabenazine (10-(11) C-DTBZ), and evaluated its potential as a vesicular monoamine transporter 2 (VMAT2) radioligand. The radiolabeled precursor 10-O-desmethyl-dihydrotetrabenazine (10-O-desmethyl-DTBZ) was prepared with a six-step reaction using 3-methoxy-4-benzyloxybenzaldehyde as starting material. 10-(11) C-DTBZ was synthesized by heating 1.0 mg of 10-hydroxy precursor and (11) C-methyl iodide in the presence of 0.3 mL of dimethyl sulfoxide and 4.0 µL of 3 N KOH at room temperature for 3 min. After purification by solid phase extraction using an alumina Sep-Pak cartridge, the final 10-(11) C-DTBZ product was obtained with a radiochemical purity of >99% and an uncorrected radiochemical yield of 18-26% (end of bombardment (EOB), n = 6). The overall synthesis time was approximately 20 min from the EOB to release of the product for quality control. Using small-animal positron emission tomography (microPET), the striatum of normal rats was found to exhibit symmetrical labeling (STR /STL = 0.98 ± 0.05, n = 3) and the highest uptake of radioactivity (striatum/cerebellum, ST/CB = 2.89 ± 0.31 at 30-60 min, n = 3). In contrast, rats with 6-hydroxydopamine unilateral lesions yielded asymmetrical striatal images with a higher 10-(11) C-DTBZ concentration on the unlesioned side (STunlesioned /CB = 2.53 ± 0.18, at 30-60 min, n = 3) compared with the lesioned side (STlesioned /CB = 1.26 ± 0.10, n = 3). These results suggest that 10-(11) C-DTBZ may represent a promising PET radiotracer for imaging VMAT2.
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Affiliation(s)
- Xiaomin Li
- Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, P. R. China
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Wimalasena K. Vesicular monoamine transporters: structure-function, pharmacology, and medicinal chemistry. Med Res Rev 2011; 31:483-519. [PMID: 20135628 PMCID: PMC3019297 DOI: 10.1002/med.20187] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Vesicular monoamine transporters (VMAT) are responsible for the uptake of cytosolic monoamines into synaptic vesicles in monoaminergic neurons. Two closely related VMATs with distinct pharmacological properties and tissue distributions have been characterized. VMAT1 is preferentially expressed in neuroendocrine cells and VMAT2 is primarily expressed in the CNS. The neurotoxicity and addictive properties of various psychostimulants have been attributed, at least partly, to their interference with VMAT2 functions. The quantitative assessment of the VMAT2 density by PET scanning has been clinically useful for early diagnosis and monitoring of the progression of Parkinson's and Alzheimer's diseases and drug addiction. The classical VMAT2 inhibitor, tetrabenazine, has long been used for the treatment of chorea associated with Huntington's disease in the United Kingdom, Canada, and Australia, and recently approved in the United States. The VMAT2 imaging may also be useful for exploiting the onset of diabetes mellitus, as VMAT2 is also expressed in the β-cells of the pancreas. VMAT1 gene SLC18A1 is a locus with strong evidence of linkage with schizophrenia and, thus, the polymorphic forms of the VMAT1 gene may confer susceptibility to schizophrenia. This review summarizes the current understanding of the structure-function relationships of VMAT2, and the role of VMAT2 on addiction and psychostimulant-induced neurotoxicity, and the therapeutic and diagnostic applications of specific VMAT2 ligands. The evidence for the linkage of VMAT1 gene with schizophrenia and bipolar disorder I is also discussed.
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Guillot TS, Miller GW. Protective actions of the vesicular monoamine transporter 2 (VMAT2) in monoaminergic neurons. Mol Neurobiol 2009; 39:149-70. [PMID: 19259829 DOI: 10.1007/s12035-009-8059-y] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2008] [Accepted: 02/18/2009] [Indexed: 12/13/2022]
Abstract
Vesicular monoamine transporters (VMATs) are responsible for the packaging of neurotransmitters such as dopamine, serotonin, norepinephrine, and epinephrine into synaptic vesicles. These proteins evolved from precursors in the major facilitator superfamily of transporters and are among the members of the toxin extruding antiporter family. While the primary function of VMATs is to sequester neurotransmitters within vesicles, they can also translocate toxicants away from cytosolic sites of action. In the case of dopamine, this dual role of VMAT2 is combined-dopamine is more readily oxidized in the cytosol where it can cause oxidative stress so packaging into vesicles serves two purposes: neurotransmission and neuroprotection. Furthermore, the deleterious effects of exogenous toxicants on dopamine neurons, such as MPTP, can be attenuated by VMAT2 activity. The active metabolite of MPTP can be kept within vesicles and prevented from disrupting mitochondrial function thereby sparing the dopamine neuron. The highly addictive drug methamphetamine is also neurotoxic to dopamine neurons by using dopamine itself to destroy the axon terminals. Methamphetamine interferes with vesicular sequestration and increases the production of dopamine, escalating the amount in the cytosol and leading to oxidative damage of terminal components. Vesicular transport seems to resist this process by sequestering much of the excess dopamine, which is illustrated by the enhanced methamphetamine neurotoxicity in VMAT2-deficient mice. It is increasingly evident that VMAT2 provides neuroprotection from both endogenous and exogenous toxicants and that while VMAT2 has been adapted by eukaryotes for synaptic transmission, it is derived from phylogenetically ancient proteins that originally evolved for the purpose of cellular protection.
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Affiliation(s)
- Thomas S Guillot
- Center for Neurodegenerative Disease, Emory University, Atlanta, GA, USA
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Zheng G, Dwoskin LP, Crooks PA. Vesicular monoamine transporter 2: role as a novel target for drug development. AAPS JOURNAL 2006; 8:E682-92. [PMID: 17233532 PMCID: PMC2751365 DOI: 10.1208/aapsj080478] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In the central nervous system, vesicular monoamine transporter 2 (VMAT2) is the only transporter that moves cytoplasmic dopamine (DA) into synaptic vesicles for storage and subsequent exocytotic release. Pharmacologically enhancing DA sequestration by VMAT2, and thus preventing the oxidation of DA in the cytoplasm, may be a strategy for treating diseases such as Parkinson's disease. VMAT2 may also be a novel target for the development of treatments for psychostimulant abuse. This review summarizes the possible role of VMAT2 as a therapeutic target, VMAT2 ligands reported in the literature, and the structure-activity relationship of these ligands, including tetrabenazine analogs, ketanserin analogs, lobeline analogs, and 3-amine-2-phenylpropene analogs. The molecular structure of VMAT2 and its relevance to ligand binding are briefly discussed.
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Affiliation(s)
- Guangrong Zheng
- College of Pharmacy, University of Kentucky, Department of Pharmaceutical Sciences, 907 Rose Street, Room 501B, 40536-0082 Lexington, KY
| | - Linda P. Dwoskin
- College of Pharmacy, University of Kentucky, Department of Pharmaceutical Sciences, 907 Rose Street, Room 501B, 40536-0082 Lexington, KY
| | - Peter A. Crooks
- College of Pharmacy, University of Kentucky, Department of Pharmaceutical Sciences, 907 Rose Street, Room 501B, 40536-0082 Lexington, KY
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