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Mori D, Kimura H, Kawashima H, Yagi Y, Arimitsu K, Ono M, Saji H. Development of 99mTc radiolabeled A85380 derivatives targeting cerebral nicotinic acetylcholine receptor: Novel radiopharmaceutical ligand 99mTc-A-YN-IDA-C4. Bioorg Med Chem 2019; 27:4200-4210. [PMID: 31401009 DOI: 10.1016/j.bmc.2019.07.053] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 07/25/2019] [Accepted: 07/30/2019] [Indexed: 01/22/2023]
Abstract
Nicotinic acetylcholine receptors (nAChRs) are pentameric ligand-gated ion channels that have been implicated in higher brain functions. To elucidate the functional mechanisms underlying nAChRs and contribute significantly to development of drugs targeting neurological and neuropsychiatric diseases, non-invasive nuclear medical imaging can be used for evaluation. In addition, technetium-99m (99mTc) is a versatile radionuclide used clinically as a tracer in single-photon emission computed tomography. Because A85380 is known as a potent α4β2-nAChR agonist, we prepared A85380 derivatives labeled with 99mTc using a bifunctional chelate system. A computational scientific approach was used to design the probe efficiently. We used non-radioactive rhenium (Re) for a 99mTc analog and found that one of the derivatives, Re-A-YN-IDA-C4, exhibited high binding affinity at α4β2-nAChR in both the docking simulation (-19.3 kcal/mol) and binding assay (Ki = 0.4 ± 0.04 nM). Further, 99mTc-A-YN-IDA-C4 was synthesized using microwaves, and its properties were examined. Consequently, we found that 99mTc-A-YN-IDA-C4, with a structure optimized by using computational chemistry techniques, maintained affinity and selectivity for nAChR in vitro and possessed efficient characteristics as a nuclear medicine molecular imaging probe, demonstrated usefulness of computational scientific approach for molecular improvement strategy.
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Affiliation(s)
- Daisuke Mori
- Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Hiroyuki Kimura
- Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan; Department of Analytical and Bioinorganic Chemistry, Kyoto Pharmaceutical University, Kyoto, Japan.
| | - Hidekazu Kawashima
- Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan; Radioisotope Research Center, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Yusuke Yagi
- Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan; Department of Analytical and Bioinorganic Chemistry, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Kenji Arimitsu
- Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan; Department of Analytical and Bioinorganic Chemistry, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Masahiro Ono
- Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Hideo Saji
- Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan.
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Synthesis and biological evaluation of Tc-99m-cyclopentadienyltricarbonyl-technetium-labeled A-85380: An imaging probe for single-photon emission computed tomography investigation of nicotinic acetylcholine receptors in the brain. Bioorg Med Chem 2019; 27:2245-2252. [PMID: 31047775 DOI: 10.1016/j.bmc.2019.04.030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 04/23/2019] [Accepted: 04/25/2019] [Indexed: 10/27/2022]
Abstract
We have designed (S)-(5-(azetidin-2-ylmethoxy)pyridine-3-yl)methyl cyclopentadienyltricarbonyl technetium carboxylate ([99mTc]CPTT-A-E) with high affinity for nicotinic acetylcholine receptors (nAChRs) using (2(S)-azetidinylmethoxy)-pyridine (A-85380) as the lead compound to develop a Tc-99m-cyclopentadienyltricarbonyl-technetium (99mTc)-labeled nAChR imaging probe. Because technetium does not contain a stable isotope, cyclopentadienyltricarbonyl rhenium (CPTR) was synthesized by coordinating rhenium, which is a homologous element having the same coordination structure as technetium. Further, the binding affinity to nAChR was evaluated. CPTR-A-E exhibited a high binding affinity to nAChR (Ki = 0.55 nM). Through the radiosynthesis of [99mTc]CPTT-A-E, an objective compound could be obtained with a radiochemical yield of 33% and a radiochemical purity of greater than 97%. In vitro autoradiographic study of the brain exhibited that the local nAChR density strongly correlated with the amount of [99mTc]CPTT-A-E that was accumulated in each region of interest. Further, the in vivo evaluation of biodistribution revealed a higher accumulation of [99mTc]CPTT-A-E in the thalamus (characterized by the high nAChR density) when compared with that in the cerebellum (characterized by the low nAChR density). Although additional studies will be necessary to improve the uptake of [99mTc]CPTT-A-E to the brain, [99mTc]CPTT-A-E met the basic requirements for nAChR imaging.
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Matsuura Y, Ueda M, Higaki Y, Sano K, Saji H, Enomoto S. Evaluation of the Relationship Between Cognitive Impairment, Glycometabolism, and Nicotinic Acetylcholine Receptor Deficits in a Mouse Model of Alzheimer’s Disease. Mol Imaging Biol 2018; 21:519-528. [DOI: 10.1007/s11307-018-1253-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Non-invasive imaging modalities to study neurodegenerative diseases of aging brain. J Chem Neuroanat 2018; 95:54-69. [PMID: 29474853 DOI: 10.1016/j.jchemneu.2018.02.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2017] [Revised: 02/16/2018] [Accepted: 02/16/2018] [Indexed: 12/13/2022]
Abstract
The aim of this article is to highlight current approaches for imaging elderly brain, indispensable for cognitive neuroscience research with emphasis on the basic physical principles of various non-invasive neuroimaging techniques. The first part of this article presents a quick overview of the primary non-invasive neuroimaging modalities used by cognitive neuroscientists such as transcranial magnetic stimulation (TMS), transcranial electrical stimulation (tES), electroencephalography (EEG), magnetoencephalography (MEG), single photon emission computed tomography (SPECT), positron emission tomography (PET), magnetic resonance spectroscopic imaging (MRSI), Profusion imaging, functional magnetic resonance imaging (fMRI), near infrared spectroscopy (NIRS) and diffusion tensor imaging (DTI) along with tractography and connectomics. The second part provides a comprehensive overview of different multimodality imaging techniques for various cognitive neuroscience studies of aging brain.
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