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Singh K, Ngo A, Keerthisinghe OV, Patel KK, Liang C, Mukherjee J. Synthesis and Evaluation of Compound Targeting α7 and β2 Subunits in Nicotinic Acetylcholinergic Receptor. Molecules 2023; 28:8128. [PMID: 38138615 PMCID: PMC10745926 DOI: 10.3390/molecules28248128] [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: 11/19/2023] [Revised: 12/07/2023] [Accepted: 12/14/2023] [Indexed: 12/24/2023] Open
Abstract
Nicotinic acetylcholine receptors (nAChRs) are involved in various central nervous system functions and have also been implicated in several neurodegenerative disorders. The heteromeric α4β2* and homomeric α7 are two major nAChR subtypes which have been studied in the brain using positron emission tomography (PET). Our comparative autoradiographic studies of the two receptor types in the mouse and rat brains show major differences in the thalamus (α4β2* >> α7), hippocampus (α7 >> α4β2*), and subiculum (α4β2* >> α7). A relatively newer heteromeric α7β2 nAChR subtype has been identified in the brain which may have a greater role in neurodegeneration. We report the development of KS7 (3-(2-(S)-azetidinylmethoxy)-5-(1,4-diaza-bicyclo[3.2.2]nonane)pyridine) which incorporates structural features of Nifzetidine (high affinity for α4β2* nAChR) and ASEM (high affinity for α7 nAChR) in an effort to target α7 and β2 subunits in α7β2 nAChR. KS7 exhibited higher affinities (IC50 = 50 to 172 nM) for [3H]cytisine radiolabeled sites and weaker affinities (IC50 = 10 μM) for [125I]-α-bungarotoxin radiolabeled rat brain sites in several brain regions. The weaker affinity of KS7 to α7 nAChR may suggest lack of binding at the α7 subunit of α7β2 nAChR. A radiolabeled derivative of KS7 may be required to identify any specific binding to brain regions suggested to contain α7β2 nAChR.
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Affiliation(s)
| | | | | | | | | | - Jogeshwar Mukherjee
- Preclinical Imaging, Department of Radiological Sciences, University of California-Irvine, Irvine, CA 92697, USA; (K.S.); (A.N.); (O.V.K.); (K.K.P.); (C.L.)
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[ 18F]Nifene PET/CT Imaging in Mice: Improved Methods and Preliminary Studies of α4β2* Nicotinic Acetylcholinergic Receptors in Transgenic A53T Mouse Model of α-Synucleinopathy and Post-Mortem Human Parkinson's Disease. Molecules 2021; 26:molecules26237360. [PMID: 34885943 PMCID: PMC8659100 DOI: 10.3390/molecules26237360] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 11/23/2021] [Accepted: 12/01/2021] [Indexed: 11/17/2022] Open
Abstract
We report [18F]nifene binding to α4β2* nicotinic acetylcholinergic receptors (nAChRs) in Parkinson’s disease (PD). The study used transgenic Hualpha-Syn(A53T) PD mouse model of α-synucleinopathy for PET/CT studies in vivo and autoradiography in vitro. Additionally, postmortem human PD brain sections comprising of anterior cingulate were used in vitro to assess translation to human studies. Because the small size of mice brain poses challenges for PET imaging, improved methods for radiosynthesis of [18F]nifene and simplified PET/CT procedures in mice were developed by comparing intravenous (IV) and intraperitoneal (IP) administered [18F]nifene. An optimal PET/CT imaging time of 30–60 min post injection of [18F]nifene was established to provide thalamus to cerebellum ratio of 2.5 (with IV) and 2 (with IP). Transgenic Hualpha-Syn(A53T) mice brain slices exhibited 20–35% decrease while in vivo a 20–30% decrease of [18F]nifene was observed. Lewy bodies and α-synuclein aggregates were confirmed in human PD brain sections which lowered the [18F]nifene binding by more than 50% in anterior cingulate. Thus [18F]nifene offers a valuable tool for PET imaging studies of PD.
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Mukherjee J, Liang C, Patel KK, Lam PQ, Mondal R. Development and evaluation of [ 125 I]IPPI for Tau imaging in postmortem human Alzheimer's disease brain. Synapse 2020; 75:e22183. [PMID: 32722889 DOI: 10.1002/syn.22183] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 07/17/2020] [Accepted: 07/18/2020] [Indexed: 01/23/2023]
Abstract
OBJECTIVE Alzheimer's disease (AD) is a neurodegenerative disease characterized by aggregation of Tau protein into paired helical filaments causing neurofibrillary tangles (NFT) in the brain. The aim of this study was to develop and evaluate the effectiveness of a novel radioiodinated tracer, 6-[125 I]iodo-3-(1H-pyrrolo[2,3-c]pyridine-1-yl)isoquinoline ([125 I]IPPI), for binding to Tau protein (Ki = 0.75 nM) in postmortem human brain (AD and cognitively normal (CN). METHODS Radiosynthesis of [125 I]IPPI was carried out by radioiododestannylation and purified chromatographically. Computational modeling studies of IPPI and MK-6240 binding on Tau fibril were evaluated. In vitro autoradiography studies were carried out with [3 H]PIB for Aβ plaques and [125 I]IPPI for Tau in AD and CN brains and evaluate drug effects. RESULTS [125 I]IPPI was produced in >95% purity. Molecular modeling of IPPI revealed binding energies of IPPI (-7.8, -8.1, -8.2, -7.5 Kcal/mol) at the four sites were comparable to MK-6240 (-8.7, -8.5, -8.3, -7.5 Kcal/mol). Ratio of average grey matter (GM) [125 I]IPPI in AD versus CN was found to be 7.31 (p = .07) and AD GM/ white matter (WM) = 4.35 (p = .09). Ratio of average GM/WM [125 I]IPPI in CN was 1.21. Binding of [125 I]IPPI correlated with the presence of Tau, confirmed by anti-Tau Dako A0024. Specifically bound [125 I]IPPI to Tau in AD brains was displaced by MK-6240 and IPPI (>90%). Monoamine oxidase inhibitors (MAO) inhibitors deprenyl and clorgyline effected [125 I]IPPI binding at >1 µM concentrations. CONCLUSION [125 I]IPPI exhibited high binding in human AD frontal cortex and anterior cingulate and is a suitable radioiodinated ligand for Tau imaging.
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Affiliation(s)
- Jogeshwar Mukherjee
- Preclinical Imaging, Department of Radiological Sciences, University of California, Irvine, CA, USA
| | - Christopher Liang
- Preclinical Imaging, Department of Radiological Sciences, University of California, Irvine, CA, USA
| | - Krystal K Patel
- Preclinical Imaging, Department of Radiological Sciences, University of California, Irvine, CA, USA
| | - Phuc Q Lam
- Preclinical Imaging, Department of Radiological Sciences, University of California, Irvine, CA, USA
| | - Rommani Mondal
- Preclinical Imaging, Department of Radiological Sciences, University of California, Irvine, CA, USA
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Tamborini L, Pinto A, Ettari R, Gotti C, Fasoli F, Conti P, De Micheli C. Synthesis and Pharmacological Evaluation of α4β2 Nicotinic Ligands with a 3-Fluoropyrrolidine Nucleus. ChemMedChem 2015; 10:1071-8. [PMID: 25882435 DOI: 10.1002/cmdc.201500073] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 03/10/2015] [Indexed: 11/09/2022]
Abstract
Nicotinic acetylcholine receptors (nAChRs) play an important role in many central nervous system disorders such as Alzheimer's and Parkinson's diseases, schizophrenia, and mood disorders. The α(4)β(2) subtype has emerged as an important target for the early diagnosis and amelioration of Alzheimer's disease symptoms. Herein we report a new class of α(4)β(2) receptor ligands characterized by a basic pyrrolidine nucleus, the basicity of which was properly decreased through the insertion of a fluorine atom at the 3-position, and a pyridine ring carrying at the 3-position substituents known to positively affect affinity and selectivity toward the α(4)β(2) subtype. Derivatives 3-(((2S,4R)-4-fluoropyrrolidin-2-yl)methoxy)-5-(phenylethynyl)pyridine (11) and 3-((4-fluorophenyl)ethynyl)-5-(((2S,4R)-4-fluoropyrrolidin-2-yl)methoxy)pyridine (12) were found to be the most promising ligands identified in this study, showing good affinity and selectivity for the α(4)β(2) subtype and physicochemical properties predictive of a relevant central nervous system penetration.
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Affiliation(s)
- Lucia Tamborini
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Milano, Via Mangiagalli 25, 20133 Milano (Italy)
| | - Andrea Pinto
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Milano, Via Mangiagalli 25, 20133 Milano (Italy).
| | - Roberta Ettari
- Dipartimento di Scienze del Farmaco e Prodotti per la Salute, Università degli Studi di Messina, Viale Annunziata 98168, Messina (Italy)
| | - Cecilia Gotti
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, CNR, Istituto di Neuroscienze, Università degli Studi di Milano, Via Vanvitelli 32, 20129 Milan (Italy)
| | - Francesca Fasoli
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, CNR, Istituto di Neuroscienze, Università degli Studi di Milano, Via Vanvitelli 32, 20129 Milan (Italy)
| | - Paola Conti
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Milano, Via Mangiagalli 25, 20133 Milano (Italy)
| | - Carlo De Micheli
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Milano, Via Mangiagalli 25, 20133 Milano (Italy)
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Kuruvilla SA, Hillmer AT, Wooten DW, Patel A, Christian BT, Mukherjee J. Synthesis and evaluation of 2-(18)F-fluoro-5-iodo-3-[2-(S)-3,4-dehydropyrrolinylmethoxy]pyridine ((18)F-Niofene) as a potential imaging agent for nicotinic α4β2 receptors. AMERICAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 2014; 4:354-364. [PMID: 24982821 PMCID: PMC4074501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 04/22/2014] [Indexed: 06/03/2023]
Abstract
Nicotinic α4β2 acetylcholine receptors (nAChRs) have been implicated in various pathophysiologies including neurodegenerative diseases. Currently, 2-(18)F-A85380 (2-FA) and 5-(123)I-A85380 (5-IA) are used separately in human PET and SPECT studies respectively and require >4-6 hours of scanning. We have developed 2-fluoro-5-iodo-3-[2-(S)-3-dehydropyrrolinylmethoxy]pyridine (niofene) as a potential PET/SPECT imaging agent for nAChRs with an aim to have rapid binding kinetics similar to that of (18)F-nifene used in PET studies. Niofene exhibited a 10-fold better in vitro binding affinity in rat brain than that of nicotine. The relative binding of niofene was similar to that of niodene and twice as better as that of nifene. In vitro autoradiography in rat brain slices alongside niodene indicated selective binding of niofene to regions consistent with α4β2 receptor distribution. Niofene, 10 nM, displaced >70% of (3)H-cytisine bound to α4β2 receptors in rat brain slices. Radiolabeling of (18)F-niofene was achieved in 10-15% radiochemical yield in high specific activities >2 Ci/μmol and showed rapid in vivo kinetics similar to that of (18)F-nifene and (18)F-nifrolene. In vivo PET in rats showed rapid uptake in the brain and selective localization in receptor regions such as the thalamus (TH). Pseudoequilibrium with (18)F-niofene was achieved in 30-40 minutes, which is similar to that of (18)F-nifene. Further evaluation of (18)F-niofene as a potential PET imaging agent is underway. Future studies will be conducted to radiolabel niofene with iodine-123 for use in SPECT imaging.
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Affiliation(s)
- Sharon A Kuruvilla
- Preclinical Imaging, Department of Radiological Sciences, University of CaliforniaIrvine, CA 92697, USA
| | - Ansel T Hillmer
- Department of Medical Physics, University of WisconsinMadison, WI 53705, USA
| | - Dustin W Wooten
- Department of Medical Physics, University of WisconsinMadison, WI 53705, USA
| | - Ashna Patel
- Preclinical Imaging, Department of Radiological Sciences, University of CaliforniaIrvine, CA 92697, USA
| | - Bradley T Christian
- Department of Medical Physics, University of WisconsinMadison, WI 53705, USA
| | - Jogeshwar Mukherjee
- Preclinical Imaging, Department of Radiological Sciences, University of CaliforniaIrvine, CA 92697, USA
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Gibbs JH, Robins LT, Zhou Z, Bobadova-Parvanova P, Cottam M, McCandless GT, Fronczek FR, Vicente MGH. Spectroscopic, computational modeling and cytotoxicity of a series of meso-phenyl and meso-thienyl-BODIPYs. Bioorg Med Chem 2013; 21:5770-81. [PMID: 23928070 PMCID: PMC4133122 DOI: 10.1016/j.bmc.2013.07.017] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 07/02/2013] [Accepted: 07/09/2013] [Indexed: 01/07/2023]
Abstract
A series of twenty-two BODIPY compounds were synthesized, containing various meso-phenyl and meso-thienyl groups, and their spectroscopic and structural properties were investigated using both experimental and computational methods. Further functionalization of the BODIPY framework via iodination at the 2,6-pyrrolic positions was explored in order to determine the effect of these heavy atoms on the photophysical and cytotoxicity of the meso-aryl-BODIPYs. BODIPYs bearing meso-thienyl substituents showed the largest red-shifted absorptions and emissions and reduced fluorescence quantum yields. The phototoxicity of the BODIPYs in human carcinoma HEp2 cells depends on both the presence of iodines and the nature of the meso-aryl groups. Six of the eleven 2,6-diiodo-BODIPYs investigated showed at least a sevenfold enhancement in phototoxicity (IC50 = 3.5-28 μM at 1.5 J/cm(2)) compared with the non-iodinated BODIPYs, while the others showed no cytotoxicity, while their singlet oxygen quantum yields ranged from 0.02 to 0.76. Among the series investigated, BODIPYs 2a and 4a bearing electron-donating meso-dimethoxyphenyl substituents showed the highest phototoxicity and dark/phototoxicity ratio, and are therefore the most promising for application in PDT.
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Affiliation(s)
- Jaime H. Gibbs
- Louisiana State University, Department of Chemistry, Baton Rouge, LA 70803, USA
| | - Larry T. Robins
- Louisiana State University, Department of Chemistry, Baton Rouge, LA 70803, USA
| | - Zehua Zhou
- Louisiana State University, Department of Chemistry, Baton Rouge, LA 70803, USA
| | | | - Michael Cottam
- Rockhurst University, Department of Chemistry, Kansas City, MO 64110, USA
| | | | - Frank R. Fronczek
- Louisiana State University, Department of Chemistry, Baton Rouge, LA 70803, USA
| | - M. Graça H. Vicente
- Louisiana State University, Department of Chemistry, Baton Rouge, LA 70803, USA
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