1
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Miyoshi H, Nakamura M. Preparation of paper scintillators and their effective use in radiation testing for α- and β- particles in radioactive liquid, solid, and gas contaminants. Appl Radiat Isot 2024; 206:111240. [PMID: 38387216 DOI: 10.1016/j.apradiso.2024.111240] [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: 11/09/2023] [Revised: 01/23/2024] [Accepted: 02/15/2024] [Indexed: 02/24/2024]
Abstract
A paper scintillator, which is composed of an organic scintillator encapsulated in silica nanoparticles adsorbed on three types of micrometer-size silica fine powder (scintillator-silica FP), was prepared by a paper making method. The scintillator-silica FP was found to be distributed throughout the paper scintillator, as shown in its emission images. Surface photoluminescence spectra depended on the amount of scintillator-silica FP and were assigned to the radioluminescence excited upon irradiation with β-particles of 45Ca. The onset channels of the pulse height spectra of 3H, 63Ni, 14C, 45Ca, 204Tl, and 32P indicated their dependence on linear energy from 18.6 to 1711 keV using the H mode in LSC-7400 for the paper scintillator to detect their maximum β-particles energies. The paper scintillator could also detect α-particles from 211At, and its pulse height spectrum was wider than that of a liquid scintillator (LS). Radon gas in air was collected using a gas sampler with the paper scintillator, and radiation from daughter nuclides was detected for 10 days. The adsorption/absorption of tritiated water onto/into the paper scintillator after dipping, dropping, and immersing the paper scintillator into tritiated water led to the detection of β-particles under different conditions of tritiated water for determining whether the radioactivity in the solution, is high or low. The paper scintillator smeared with tritiated contaminants detected tritium without requiring an LS, which is used in a smear paper.
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Affiliation(s)
- Hirokazu Miyoshi
- Advance Radiation Research, Education, and Management Center, Tokushima University, 3-18-15 Kuramoto-cho, Tokushima, 7708503, Japan.
| | - Mami Nakamura
- Advance Radiation Research, Education, and Management Center, Tokushima University, 3-18-15 Kuramoto-cho, Tokushima, 7708503, Japan
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2
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Nicoli A, Weber V, Bon C, Steuer A, Gustincich S, Gainetdinov RR, Lang R, Espinoza S, Di Pizio A. Structure-Based Discovery of Mouse Trace Amine-Associated Receptor 5 Antagonists. J Chem Inf Model 2023; 63:6667-6680. [PMID: 37847527 PMCID: PMC10647090 DOI: 10.1021/acs.jcim.3c00755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Indexed: 10/18/2023]
Abstract
Trace amine-associated receptors (TAARs) were discovered in 2001 as new members of class A G protein-coupled receptors (GPCRs). With the only exception of TAAR1, TAAR members (TAAR2-9, also known as noncanonical olfactory receptors) were originally described exclusively in the olfactory epithelium and believed to mediate the innate perception of volatile amines. However, most noncanonical olfactory receptors are still orphan receptors. Given its recently discovered nonolfactory expression and therapeutic potential, TAAR5 has been the focus of deorphanization campaigns that led to the discovery of a few druglike antagonists. Here, we report four novel TAAR5 antagonists identified through high-throughput screening, which, along with the four ligands published in the literature, constituted our starting point to design a computational strategy for the identification of TAAR5 ligands. We developed a structure-based virtual screening protocol that allowed us to identify three new TAAR5 antagonists with a hit rate of 10%. Despite lacking an experimental structure, we accurately modeled the TAAR5 binding site by integrating comparative sequence- and structure-based analyses of serotonin receptors with homology modeling and side-chain optimization. In summary, we have identified seven new TAAR5 antagonists that could serve as lead candidates for the development of new treatments for depression, anxiety, and neurodegenerative diseases.
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Affiliation(s)
- Alessandro Nicoli
- Leibniz
Institute for Food Systems Biology at the Technical University of
Munich, 85354 Freising, Germany
- Chemoinformatics
and Protein Modelling, Department of Molecular Life Sciences, School
of Life Sciences, Technical University of
Munich, 85354 Freising, Germany
| | - Verena Weber
- Leibniz
Institute for Food Systems Biology at the Technical University of
Munich, 85354 Freising, Germany
- Institute
for Advanced Simulations (IAS)-5/Institute for Neuroscience and Medicine
(INM)-9, Forschungszentrum Jülich, 52428 Jülich, Germany
- Faculty
of Mathematics, Computer Science and Natural Sciences, RWTH Aachen, Aachen, 52062 Germany
| | - Carlotta Bon
- Istituto
Italiano di Tecnologia, 16163 Genova, Italy
| | - Alexandra Steuer
- Leibniz
Institute for Food Systems Biology at the Technical University of
Munich, 85354 Freising, Germany
- Chemoinformatics
and Protein Modelling, Department of Molecular Life Sciences, School
of Life Sciences, Technical University of
Munich, 85354 Freising, Germany
| | | | - Raul R. Gainetdinov
- Institute
of Translational Biomedicine and Saint Petersburg University Hospital,
Saint Petersburg State University, Saint Petersburg 199034, Russia
| | - Roman Lang
- Leibniz
Institute for Food Systems Biology at the Technical University of
Munich, 85354 Freising, Germany
| | - Stefano Espinoza
- Istituto
Italiano di Tecnologia, 16163 Genova, Italy
- Dipartimento
di Scienze della Salute, Università
del Piemonte Orientale, 28100 Novara, Italy
| | - Antonella Di Pizio
- Leibniz
Institute for Food Systems Biology at the Technical University of
Munich, 85354 Freising, Germany
- Chemoinformatics
and Protein Modelling, Department of Molecular Life Sciences, School
of Life Sciences, Technical University of
Munich, 85354 Freising, Germany
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3
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Hetzler B, Donthamsetti P, Peitsinis Z, Stanley C, Trauner D, Isacoff EY. Optical Control of Dopamine D2-like Receptors with Cell-Specific Fast-Relaxing Photoswitches. J Am Chem Soc 2023; 145:18778-18788. [PMID: 37586061 PMCID: PMC10472511 DOI: 10.1021/jacs.3c02735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Indexed: 08/18/2023]
Abstract
Dopamine D2-like receptors (D2R, D3R, and D4R) control diverse physiological and behavioral functions and are important targets for the treatment of a variety of neuropsychiatric disorders. Their complex distribution and activation kinetics in the brain make it difficult to target specific receptor populations with sufficient precision. We describe a new toolkit of light-activatable, fast-relaxing, covalently taggable chemical photoswitches that fully activate, partially activate, or block D2-like receptors. This technology combines the spatiotemporal precision of a photoswitchable ligand (P) with cell type and spatial specificity of a genetically encoded membrane anchoring protein (M) to which the P tethers. These tools set the stage for targeting endogenous D2-like receptor signaling with molecular, cellular, and spatiotemporal precision using only one wavelength of light.
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Affiliation(s)
- Belinda
E. Hetzler
- Department
of Chemistry, New York University, New York, New York 10003, United States
| | - Prashant Donthamsetti
- Molecular
and Cell Biology, University of California,
Berkeley, Berkeley, California 94720, United States
| | - Zisis Peitsinis
- Department
of Chemistry, New York University, New York, New York 10003, United States
| | - Cherise Stanley
- Molecular
and Cell Biology, University of California,
Berkeley, Berkeley, California 94720, United States
| | - Dirk Trauner
- Department
of Chemistry, New York University, New York, New York 10003, United States
- Department
of Chemistry and Department of Systems Pharmacology and Translational
Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Ehud Y. Isacoff
- Molecular
and Cell Biology, University of California,
Berkeley, Berkeley, California 94720, United States
- Helen
Wills Neuroscience Institute, University
of California, Berkeley, California 94720, United States
- Weill Neurohub, University of California, Berkeley, Berkeley, California 94720, United States
- Molecular
Biophysics & Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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4
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Identification of Novel Dopamine D2 Receptor Ligands—A Combined In Silico/In Vitro Approach. Molecules 2022; 27:molecules27144435. [PMID: 35889317 PMCID: PMC9318694 DOI: 10.3390/molecules27144435] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 07/05/2022] [Accepted: 07/06/2022] [Indexed: 02/04/2023] Open
Abstract
Diseases of the central nervous system are an alarming global problem showing an increasing prevalence. Dopamine receptor D2 (D2R) has been shown to be involved in central nervous system diseases. While different D2R-targeting drugs have been approved by the FDA, they all suffer from major drawbacks due to promiscuous receptor activity leading to adverse effects. Increasing the number of potential D2R-targeting drug candidates bears the possibility of discovering molecules with less severe side-effect profiles. In dire need of novel D2R ligands for drug development, combined in silico/in vitro approaches have been shown to be efficient strategies. In this study, in silico pharmacophore models were generated utilizing both ligand- and structure-based approaches. Subsequently, different databases were screened for novel D2R ligands. Selected virtual hits were investigated in vitro, quantifying their binding affinity towards D2R. This workflow successfully identified six novel D2R ligands exerting micro- to nanomolar (most active compound KI = 4.1 nM) activities. Thus, the four pharmacophore models showed prospective true-positive hit rates in between 4.5% and 12%. The developed workflow and identified ligands could aid in developing novel drug candidates for D2R-associated pathologies.
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5
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Allosteric modulation of dopamine D 2L receptor in complex with G i1 and G i2 proteins: the effect of subtle structural and stereochemical ligand modifications. Pharmacol Rep 2022; 74:406-424. [PMID: 35064921 PMCID: PMC8964653 DOI: 10.1007/s43440-021-00352-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 12/17/2021] [Accepted: 12/28/2021] [Indexed: 12/28/2022]
Abstract
Background Allosteric modulation of G protein-coupled receptors (GPCRs) is nowadays one of the hot topics in drug discovery. In particular, allosteric modulators of D2 receptor have been proposed as potential modern therapeutics to treat schizophrenia and Parkinson’s disease. Methods To address some subtle structural and stereochemical aspects of allosteric modulation of D2 receptor, we performed extensive in silico studies of both enantiomers of two compounds (compound 1 and compound 2), and one of them (compound 2) was synthesized as a racemate in-house and studied in vitro. Results Our molecular dynamics simulations confirmed literature reports that the R enantiomer of compound 1 is a positive allosteric modulator of the D2L receptor, while its S enantiomer is a negative allosteric modulator. Moreover, based on the principal component analysis (PCA), we hypothesized that both enantiomers of compound 2 behave as silent allosteric modulators, in line with our in vitro studies. PCA calculations suggest that the most pronounced modulator-induced receptor rearrangements occur at the transmembrane helix 7 (TM7). In particular, TM7 bending at the conserved P7.50 and G7.42 was observed. The latter resides next to the Y7.43, which is a significant part of the orthosteric binding site. Moreover, the W7.40 conformation seems to be affected by the presence of the positive allosteric modulator. Conclusions Our work reveals that allosteric modulation of the D2L receptor can be affected by subtle ligand modifications. A change in configuration of a chiral carbon and/or minor structural modulator modifications are solely responsible for the functional outcome of the allosteric modulator. Graphical abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1007/s43440-021-00352-x.
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6
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Allikalt A, Purkayastha N, Flad K, Schmidt MF, Tabor A, Gmeiner P, Hübner H, Weikert D. Fluorescent ligands for dopamine D 2/D 3 receptors. Sci Rep 2020; 10:21842. [PMID: 33318558 PMCID: PMC7736868 DOI: 10.1038/s41598-020-78827-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 11/27/2020] [Indexed: 12/11/2022] Open
Abstract
Fluorescent ligands are versatile tools for the study of G protein-coupled receptors. Depending on the fluorophore, they can be used for a range of different applications, including fluorescence microscopy and bioluminescence or fluorescence resonance energy transfer (BRET or FRET) assays. Starting from phenylpiperazines and indanylamines, privileged scaffolds for dopamine D2-like receptors, we developed dansyl-labeled fluorescent ligands that are well accommodated in the binding pockets of D2 and D3 receptors. These receptors are the target proteins for the therapy for several neurologic and psychiatric disorders, including Parkinson’s disease and schizophrenia. The dansyl-labeled ligands exhibit binding affinities up to 0.44 nM and 0.29 nM at D2R and D3R, respectively. When the dansyl label was exchanged for sterically more demanding xanthene or cyanine dyes, fluorescent ligands 10a-c retained excellent binding properties and, as expected from their indanylamine pharmacophore, acted as agonists at D2R. While the Cy3B-labeled ligand 10b was used to visualize D2R and D3R on the surface of living cells by total internal reflection microscopy, ligand 10a comprising a rhodamine label showed excellent properties in a NanoBRET binding assay at D3R.
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Affiliation(s)
- Anni Allikalt
- Department of Chemistry and Pharmacy, Medicinal Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Nikolaus-Fiebiger-Str. 10, 91058, Erlangen, Germany
| | - Nirupam Purkayastha
- Department of Chemistry and Pharmacy, Medicinal Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Nikolaus-Fiebiger-Str. 10, 91058, Erlangen, Germany
| | - Khajidmaa Flad
- Department of Chemistry and Pharmacy, Medicinal Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Nikolaus-Fiebiger-Str. 10, 91058, Erlangen, Germany
| | - Maximilian F Schmidt
- Department of Chemistry and Pharmacy, Medicinal Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Nikolaus-Fiebiger-Str. 10, 91058, Erlangen, Germany
| | - Alina Tabor
- Department of Chemistry and Pharmacy, Medicinal Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Nikolaus-Fiebiger-Str. 10, 91058, Erlangen, Germany
| | - Peter Gmeiner
- Department of Chemistry and Pharmacy, Medicinal Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Nikolaus-Fiebiger-Str. 10, 91058, Erlangen, Germany
| | - Harald Hübner
- Department of Chemistry and Pharmacy, Medicinal Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Nikolaus-Fiebiger-Str. 10, 91058, Erlangen, Germany
| | - Dorothee Weikert
- Department of Chemistry and Pharmacy, Medicinal Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Nikolaus-Fiebiger-Str. 10, 91058, Erlangen, Germany.
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7
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Egyed A, Domány-Kovács K, Koványi B, Horti F, Kurkó D, Kiss DJ, Pándy-Szekeres G, Greiner I, Keserű GM. Controlling receptor function from the extracellular vestibule of G-protein coupled receptors. Chem Commun (Camb) 2020; 56:14167-14170. [PMID: 33079104 DOI: 10.1039/d0cc05532h] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Receptor function is traditionally controlled from the orthosteric binding site of G-protein coupled receptors. Here, we show that the functional activity and signalling of human dopamine D2 and D3 receptor ligands can be fine-tuned from the extracellular secondary binding pocket (SBP) located far from the signalling interface suggesting optimization of the SBP binding part of bitopic ligands might be a useful strategy to develop GPCR ligands with designed functional and signalling profile.
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Affiliation(s)
- Attila Egyed
- Medicinal Chemistry Research Group, Research Center for Natural Sciences, Magyar Tudósok krt. 2, Budapest, H-1117, Hungary.
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8
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Chemogenetics a robust approach to pharmacology and gene therapy. Biochem Pharmacol 2020; 175:113889. [DOI: 10.1016/j.bcp.2020.113889] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 02/26/2020] [Indexed: 12/20/2022]
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9
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Preferential Coupling of Dopamine D 2S and D 2L Receptor Isoforms with G i1 and G i2 Proteins-In Silico Study. Int J Mol Sci 2020; 21:ijms21020436. [PMID: 31936673 PMCID: PMC7013695 DOI: 10.3390/ijms21020436] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 12/31/2019] [Accepted: 01/06/2020] [Indexed: 02/06/2023] Open
Abstract
The dopamine D2 receptor belongs to rhodopsin-like G protein-coupled receptors (GPCRs) and it is an important molecular target for the treatment of many disorders, including schizophrenia and Parkinson's disease. Here, computational methods were used to construct the full models of the dopamine D2 receptor short (D2S) and long (D2L) isoforms (differing with 29 amino acids insertion in the third intracellular loop, ICL3) and to study their coupling with Gi1 and Gi2 proteins. It was found that the D2L isoform preferentially couples with the Gi2 protein and D2S isoform with the Gi1 protein, which is in accordance with experimental data. Our findings give mechanistic insight into the interplay between isoforms of dopamine D2 receptors and Gi proteins subtypes, which is important to understand signaling by these receptors and their mediation by pharmaceuticals, in particular psychotic and antipsychotic agents.
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10
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Bueschbell B, Barreto CAV, Preto AJ, Schiedel AC, Moreira IS. A Complete Assessment of Dopamine Receptor- Ligand Interactions through Computational Methods. Molecules 2019; 24:E1196. [PMID: 30934701 PMCID: PMC6479630 DOI: 10.3390/molecules24071196] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 03/21/2019] [Accepted: 03/23/2019] [Indexed: 12/22/2022] Open
Abstract
Background: Selectively targeting dopamine receptors (DRs) has been a persistent challenge in the last years for the development of new treatments to combat the large variety of diseases involving these receptors. Although, several drugs have been successfully brought to market, the subtype-specific binding mode on a molecular basis has not been fully elucidated. Methods: Homology modeling and molecular dynamics were applied to construct robust conformational models of all dopamine receptor subtypes (D₁-like and D₂-like). Fifteen structurally diverse ligands were docked. Contacts at the binding pocket were fully described in order to reveal new structural findings responsible for selective binding to DR subtypes. Results: Residues of the aromatic microdomain were shown to be responsible for the majority of ligand interactions established to all DRs. Hydrophobic contacts involved a huge network of conserved and non-conserved residues between three transmembrane domains (TMs), TM2-TM3-TM7. Hydrogen bonds were mostly mediated by the serine microdomain. TM1 and TM2 residues were main contributors for the coupling of large ligands. Some amino acid groups form electrostatic interactions of particular importance for D₁R-like selective ligands binding. Conclusions: This in silico approach was successful in showing known receptor-ligand interactions as well as in determining unique combinations of interactions, which will support mutagenesis studies to improve the design of subtype-specific ligands.
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Affiliation(s)
- Beatriz Bueschbell
- PharmaCenter Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry I, University of Bonn, D-53121 Bonn, Germany.
| | - Carlos A V Barreto
- Center for Neuroscience and Cell Biology, UC- Biotech Parque Tecnológico de Cantanhede, Núcleo 04, Lote B, 3060-197 Cantanhede, Portugal.
| | - António J Preto
- Center for Neuroscience and Cell Biology, UC- Biotech Parque Tecnológico de Cantanhede, Núcleo 04, Lote B, 3060-197 Cantanhede, Portugal.
| | - Anke C Schiedel
- PharmaCenter Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry I, University of Bonn, D-53121 Bonn, Germany.
| | - Irina S Moreira
- Center for Neuroscience and Cell Biology, UC- Biotech Parque Tecnológico de Cantanhede, Núcleo 04, Lote B, 3060-197 Cantanhede, Portugal.
- Institute for Interdisciplinary Research, University of Coimbra, 3004-531 Coimbra, Portugal.
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11
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Vass M, Podlewska S, de Esch IJP, Bojarski AJ, Leurs R, Kooistra AJ, de Graaf C. Aminergic GPCR-Ligand Interactions: A Chemical and Structural Map of Receptor Mutation Data. J Med Chem 2018; 62:3784-3839. [PMID: 30351004 DOI: 10.1021/acs.jmedchem.8b00836] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The aminergic family of G protein-coupled receptors (GPCRs) plays an important role in various diseases and represents a major drug discovery target class. Structure determination of all major aminergic subfamilies has enabled structure-based ligand design for these receptors. Site-directed mutagenesis data provides an invaluable complementary source of information for elucidating the structural determinants of binding of different ligand chemotypes. The current study provides a comparative analysis of 6692 mutation data points on 34 aminergic GPCR subtypes, covering the chemical space of 540 unique ligands from mutagenesis experiments and information from experimentally determined structures of 52 distinct aminergic receptor-ligand complexes. The integrated analysis enables detailed investigation of structural receptor-ligand interactions and assessment of the transferability of combined binding mode and mutation data across ligand chemotypes and receptor subtypes. An overview is provided of the possibilities and limitations of using mutation data to guide the design of novel aminergic receptor ligands.
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Affiliation(s)
- Márton Vass
- Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute for Molecules, Medicines and Systems (AIMMS) , VU University Amsterdam , 1081HZ Amsterdam , The Netherlands
| | - Sabina Podlewska
- Department of Medicinal Chemistry, Institute of Pharmacology , Polish Academy of Sciences , Smętna 12 , PL31-343 Kraków , Poland
| | - Iwan J P de Esch
- Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute for Molecules, Medicines and Systems (AIMMS) , VU University Amsterdam , 1081HZ Amsterdam , The Netherlands
| | - Andrzej J Bojarski
- Department of Medicinal Chemistry, Institute of Pharmacology , Polish Academy of Sciences , Smętna 12 , PL31-343 Kraków , Poland
| | - Rob Leurs
- Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute for Molecules, Medicines and Systems (AIMMS) , VU University Amsterdam , 1081HZ Amsterdam , The Netherlands
| | - Albert J Kooistra
- Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute for Molecules, Medicines and Systems (AIMMS) , VU University Amsterdam , 1081HZ Amsterdam , The Netherlands.,Department of Drug Design and Pharmacology , University of Copenhagen , Universitetsparken 2 , 2100 Copenhagen , Denmark
| | - Chris de Graaf
- Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute for Molecules, Medicines and Systems (AIMMS) , VU University Amsterdam , 1081HZ Amsterdam , The Netherlands.,Sosei Heptares , Steinmetz Building, Granta Park, Great Abington , Cambridge CB21 6DG , U.K
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12
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Lachmann D, Studte C, Männel B, Hübner H, Gmeiner P, König B. Photochromic Dopamine Receptor Ligands Based on Dithienylethenes and Fulgides. Chemistry 2017. [PMID: 28650111 DOI: 10.1002/chem.201702147] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We describe the incorporation of the well-investigated class of photochromic dithienylethenes (DTEs) and fulgides into known dopamine receptor ligands such as 1,4-disubstituted aromatic and hydroxybenzoxazinone piperazines as well as aminoindanes. Subtype and functional selective photochromic ligands were obtained and characterized by NMR and UV/VIS spectroscopic measurements. The photophysical properties of the DTE based dopamine ligands revealed a high fatigue resistance for the diarylmaleimides, but the ringclosure could not be accomplished in polar solvents due to a known twisted intramolecular charge transfer (TICT). Several cyclopentene-DTEs showed high PSS, but a fast degradation by forming an irreversible byproduct. Focusing on the fulgides, high photostationary states and switching in polar solvents were possible. The compounds 43, 45 and 46 containing the isopropyl group showed only isomerization between the open E-form and the closed C-form. At a concentration of 1 nm, the cyclopentene-DTE 29-open showed a more than 11-fold higher activation of D2S , a pharmacologically important G protein-coupled receptor, than its photochromic congener 29-closed. Interestingly, the fulgimide-based pair 52-(E)-open/52-closed could be discovered as an alternative photoswitch with inverse activation properties exhibiting four-fold higher activity in the closed state.
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Affiliation(s)
- Daniel Lachmann
- Institute of Organic Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, Universitätsstrasse 31, 93053, Regensburg, Germany
| | - Carolin Studte
- Institute of Organic Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, Universitätsstrasse 31, 93053, Regensburg, Germany
| | - Barbara Männel
- Department of Chemistry and Pharmacy, Friedrich-Alexander University, Emil Fischer Center, Schuhstrasse 19, 91052, Erlangen, Germany
| | - Harald Hübner
- Department of Chemistry and Pharmacy, Friedrich-Alexander University, Emil Fischer Center, Schuhstrasse 19, 91052, Erlangen, Germany
| | - Peter Gmeiner
- Department of Chemistry and Pharmacy, Friedrich-Alexander University, Emil Fischer Center, Schuhstrasse 19, 91052, Erlangen, Germany
| | - Burkhard König
- Institute of Organic Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, Universitätsstrasse 31, 93053, Regensburg, Germany
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13
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Bartuschat AL, Schellhorn T, Hübner H, Gmeiner P, Heinrich MR. Fluoro-substituted phenylazocarboxamides: Dopaminergic behavior and N-arylating properties for irreversible binding. Bioorg Med Chem 2015; 23:3938-47. [DOI: 10.1016/j.bmc.2014.12.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 12/08/2014] [Accepted: 12/10/2014] [Indexed: 10/24/2022]
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14
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Kling RC, Tschammer N, Lanig H, Clark T, Gmeiner P. Active-state model of a dopamine D2 receptor-Gαi complex stabilized by aripiprazole-type partial agonists. PLoS One 2014; 9:e100069. [PMID: 24932547 PMCID: PMC4059746 DOI: 10.1371/journal.pone.0100069] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 05/20/2014] [Indexed: 11/18/2022] Open
Abstract
Partial agonists exhibit a submaximal capacity to enhance the coupling of one receptor to an intracellular binding partner. Although a multitude of studies have reported different ligand-specific conformations for a given receptor, little is known about the mechanism by which different receptor conformations are connected to the capacity to activate the coupling to G-proteins. We have now performed molecular-dynamics simulations employing our recently described active-state homology model of the dopamine D2 receptor-Gαi protein-complex coupled to the partial agonists aripiprazole and FAUC350, in order to understand the structural determinants of partial agonism better. We have compared our findings with our model of the D2R-Gαi-complex in the presence of the full agonist dopamine. The two partial agonists are capable of inducing different conformations of important structural motifs, including the extracellular loop regions, the binding pocket and, in particular, intracellular G-protein-binding domains. As G-protein-coupling to certain intracellular epitopes of the receptor is considered the key step of allosterically triggered nucleotide-exchange, it is tempting to assume that impaired coupling between the receptor and the G-protein caused by distinct ligand-specific conformations is a major determinant of partial agonist efficacy.
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Affiliation(s)
- Ralf C. Kling
- Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich Alexander University, Erlangen, Germany
- Department of Chemistry and Pharmacy, Computer Chemistry Center, Friedrich Alexander University, Erlangen, Germany
| | - Nuska Tschammer
- Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich Alexander University, Erlangen, Germany
| | - Harald Lanig
- Department of Chemistry and Pharmacy, Computer Chemistry Center, Friedrich Alexander University, Erlangen, Germany
- Central Institute for Scientific Computing, Friedrich Alexander University, Erlangen, Germany
| | - Timothy Clark
- Department of Chemistry and Pharmacy, Computer Chemistry Center, Friedrich Alexander University, Erlangen, Germany
- Centre for Molecular Design, University of Portsmouth, King Henry Building, Portsmouth, United Kingdom
| | - Peter Gmeiner
- Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich Alexander University, Erlangen, Germany
- * E-mail:
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15
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Malo M, Persson R, Svensson P, Luthman K, Brive L. Development of 7TM receptor-ligand complex models using ligand-biased, semi-empirical helix-bundle repacking in torsion space: application to the agonist interaction of the human dopamine D2 receptor. J Comput Aided Mol Des 2013; 27:277-91. [PMID: 23553533 PMCID: PMC3639355 DOI: 10.1007/s10822-013-9640-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 03/20/2013] [Indexed: 11/30/2022]
Abstract
Prediction of 3D structures of membrane proteins, and of G-protein coupled receptors (GPCRs) in particular, is motivated by their importance in biological systems and the difficulties associated with experimental structure determination. In the present study, a novel method for the prediction of 3D structures of the membrane-embedded region of helical membrane proteins is presented. A large pool of candidate models are produced by repacking of the helices of a homology model using Monte Carlo sampling in torsion space, followed by ranking based on their geometric and ligand-binding properties. The trajectory is directed by weak initial restraints to orient helices towards the original model to improve computation efficiency, and by a ligand to guide the receptor towards a chosen conformational state. The method was validated by construction of the β1 adrenergic receptor model in complex with (S)-cyanopindolol using bovine rhodopsin as template. In addition, models of the dopamine D2 receptor were produced with the selective and rigid agonist (R)-N-propylapomorphine ((R)-NPA) present. A second quality assessment was implemented by evaluating the results from docking of a library of 29 ligands with known activity, which further discriminated between receptor models. Agonist binding and recognition by the dopamine D2 receptor is interpreted using the 3D structure model resulting from the approach. This method has a potential for modeling of all types of helical transmembrane proteins for which a structural template with sequence homology sufficient for homology modeling is not available or is in an incorrect conformational state, but for which sufficient empirical information is accessible.
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Affiliation(s)
- Marcus Malo
- Department of Chemistry and Molecular Biology, University of Gothenburg, SE-412 96 Göteborg, Sweden
| | - Ronnie Persson
- Department of Chemistry and Molecular Biology, University of Gothenburg, SE-412 96 Göteborg, Sweden
| | - Peder Svensson
- NeuroSearch Sweden AB, Arvid Wallgrens Backe 20, SE-413 46 Göteborg, Sweden
- Present Address: Astra Zeneca R&D Mölndal, SE-431 83 Mölndal, Sweden
| | - Kristina Luthman
- Department of Chemistry and Molecular Biology, University of Gothenburg, SE-412 96 Göteborg, Sweden
| | - Lars Brive
- Department of Chemistry and Molecular Biology, University of Gothenburg, SE-412 96 Göteborg, Sweden
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Box 440, SE-405 30 Göteborg, Sweden
- Cygnal Bioscience, Björnvägen 15, SE-435 43 Pixbo, Sweden
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16
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Pettersson F, Svensson P, Waters S, Waters N, Sonesson C. Synthesis, pharmacological evaluation and QSAR modeling of mono-substituted 4-phenylpiperidines and 4-phenylpiperazines. Eur J Med Chem 2013; 62:241-55. [PMID: 23353756 DOI: 10.1016/j.ejmech.2012.12.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 12/13/2012] [Accepted: 12/17/2012] [Indexed: 01/11/2023]
Abstract
A series of mono-substituted 4-phenylpiperidines and -piperazines have been synthesized and their effects on the dopaminergic system tested in vivo. The structure activity relationship (SAR) revealed that the position and physicochemical character of the aromatic substituent proved to be critical for the levels of 3,4-dihydroxyphenylacetic acid (DOPAC) in the brain of freely moving rats. In order to investigate how the structural properties of these compounds affect the response, a set of tabulated and calculated physicochemical descriptors were modeled against the in vivo effects using partial least square (PLS) regression. Furthermore, the binding affinities to the dopamine D2 (DA D2) receptor and monoamine oxidase A (MAO A) enzyme were determined for a chosen subset and QSAR models using the same descriptors as in the in vivo model were produced to investigate the mechanisms leading to the observed DOPAC response. These models, in combination with a strong correlation between the levels of striatal DOPAC and the affinities to DA D2 and MAO A, provides a comprehensive understanding of the biological response for compounds in this class.
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Affiliation(s)
- Fredrik Pettersson
- NeuroSearch Sweden AB, Arvid Wallgrens Backe 20, S-413 46 Göteborg, Sweden.
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17
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Malo M, Brive L, Luthman K, Svensson P. Investigation of D₂ receptor-agonist interactions using a combination of pharmacophore and receptor homology modeling. ChemMedChem 2012; 7:471-82, 338. [PMID: 22315215 PMCID: PMC3382189 DOI: 10.1002/cmdc.201100545] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Revised: 01/05/2012] [Indexed: 01/21/2023]
Abstract
A combined modeling approach was used to identify structural factors that underlie the structure–activity relationships (SARs) of full dopamine D2 receptor agonists and structurally similar inactive compounds. A 3D structural model of the dopamine D2 receptor was constructed, with the agonist (−)-(R)-2-OH-NPA present in the binding site during the modeling procedure. The 3D model was evaluated and compared with our previously published D2 agonist pharmacophore model. The comparison revealed an inconsistency between the projected hydrogen bonding feature (Ser-TM5) in the pharmacophore model and the TM5 region in the structure model. A new refined pharmacophore model was developed, guided by the shape of the binding site in the receptor model and with less emphasis on TM5 interactions. The combination of receptor and pharmacophore modeling also identified the importance of His3936.55 for agonist binding. This convergent 3D pharmacophore and protein structure modeling strategy is considered to be general and can be highly useful in less well-characterized systems to explore ligand–receptor interactions. The strategy has the potential to identify weaknesses in the individual models and thereby provides an opportunity to improve the discriminating predictivity of both pharmacophore searches and structure-based virtual screens.
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Affiliation(s)
- Marcus Malo
- Department of Chemistry, Medicinal Chemistry, University of Gothenburg, 41296 Göteborg, Sweden
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18
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Koschatzky S, Gmeiner P. Selective agonists for dopamine/neurotensin receptor heterodimers. ChemMedChem 2011; 7:509-14. [PMID: 22213714 DOI: 10.1002/cmdc.201100499] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Revised: 12/05/2011] [Indexed: 12/26/2022]
Abstract
The neuromodulatory peptide neurotensin has been described to functionally interact with dopaminergic pathways of the human brain. We employed radioligand binding studies to investigate the physical interaction between co-expressed dopamine D(2L) or D₃ and neurotensin NTS₁ or NTS₂ receptors. Substantial cross-inhibitory effects of both receptor subtypes NTS(1) and NTS₂ on the agonist binding of D(2L) or D₃ were detected in the presence of neurotensin. To identify ligand-specific modulation and subtype-dependent differences, the novel dopamine receptor agonists 5 and 6 bearing the 7-OH-DPAT pharmacophore were synthesized. Exceptional ligand specificity was observed for D₃-NTS₂ co-expression, which gave a 20-fold decrease in affinity for biphenylcarboxamide 5 in the presence of neurotensin. Comparing the binding properties of dopaminergic compounds in the presence of neurotensin, dopamine receptor subtype-selective profiles of the cross-inhibitory effect of neurotensin were observed.
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Affiliation(s)
- Susanne Koschatzky
- Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich Alexander University, Schuhstr. 19, 91052 Erlangen, Germany
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19
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Kühhorn J, Götz A, Hübner H, Thompson D, Whistler J, Gmeiner P. Development of a bivalent dopamine D₂ receptor agonist. J Med Chem 2011; 54:7911-9. [PMID: 21999579 DOI: 10.1021/jm2009919] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Bivalent D₂ agonists may function as useful molecular probes for the discovery of novel neurological therapeutics. On the basis of our recently developed bivalent dopamine D₂ receptor antagonists of type 1, the bivalent agonist 2 was synthesized when a spacer built from 22 atoms was employed. Compared to the monovalent control compound 6 containing a capped spacer, the bis-aminoindane derivative 2 revealed substantial steepening of the competition curve, indicating a bivalent binding mode. Dimer-specific Hill slopes were not a result of varying functional properties because both the dopaminergic 2 and the monovalent control agent 6 proved to be D₂ agonists substantially inhibiting cAMP accumulation and inducing D₂ receptor internalization. Investigation of the heterobivalent ligands 8 and 9, containing an agonist and a phenylpiperazine-based antagonist pharmacophore, revealed moderate steepening of the displacement curves and antagonist to very weak partial agonist properties.
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Affiliation(s)
- Julia Kühhorn
- Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich Alexander University, Schuhstraße 19, D-91052 Erlangen, Germany
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20
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Koschatzky S, Tschammer N, Gmeiner P. Cross-receptor interactions between dopamine D2L and neurotensin NTS1 receptors modulate binding affinities of dopaminergics. ACS Chem Neurosci 2011; 2:308-16. [PMID: 22778874 DOI: 10.1021/cn200020y] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Accepted: 04/11/2011] [Indexed: 11/30/2022] Open
Abstract
Dopaminergic systems have been described to functionally interact with the neuromodulatory peptide neurotensin. Employing fluorescence detected coimmunoprecipitation and radioligand binding experiments, we herein demonstrate that coexpression of dopamine D(2L) receptor and the neurotensin receptor subtype NTS(1) leads to physical interaction and the formation of heteromers in transfected human embryonic kidney 293 cells. In this in vitro system, a trans-inhibitory effect on the agonist binding affinity of D(2) was observed in presence of neurotensin. To correlate between the functional properties of dopaminergic agents and the magnitude of neurotensin-induced modulation of D(2L) binding affinities in cells coexpressing D(2L) and NTS(1), a structurally diverse set of dopamine receptor agonists, partial agonists, and antagonists was tested. Ligand specific profiles indicating substantial bias between ligand efficacy and transmodulation were discovered, suggesting a heteromerization-based functional selectivity. In the presence of neurotensin, the novel D(2) agonist FAUC 326 displayed a 34-fold decrease of binding affinity in cells coexpressing D(2L) and NTS(1).
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Affiliation(s)
- Susanne Koschatzky
- Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich-Alexander University, Schuhstrasse 19, D- 91052 Erlangen, Germany
| | - Nuska Tschammer
- Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich-Alexander University, Schuhstrasse 19, D- 91052 Erlangen, Germany
| | - Peter Gmeiner
- Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich-Alexander University, Schuhstrasse 19, D- 91052 Erlangen, Germany
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21
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Tschammer N, Elsner J, Goetz A, Ehrlich K, Schuster S, Ruberg M, Kühhorn J, Thompson D, Whistler J, Hübner H, Gmeiner P. Highly potent 5-aminotetrahydropyrazolopyridines: enantioselective dopamine D3 receptor binding, functional selectivity, and analysis of receptor-ligand interactions. J Med Chem 2011; 54:2477-91. [PMID: 21388142 DOI: 10.1021/jm101639t] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Heterocyclic dopamine surrogates of types 5 and 7 were synthesized and investigated for their dopaminergic properties. The enantiomerically pure biphenylcarboxamide (S)-5a displayed an outstanding K(i) of 27 pM at the agonist-labeled D(3) receptor and significant selectivity over the D(2) subtype. Measurement of [(35)S]GTPγS incorporation in the presence of a coexpressed PTX-insensitive G(α0-1) subunit indicated highly efficient G-protein coupling. Comparison of ligand efficacy data from cAMP accumulation and [(3)H]thymidine incorporation experiments revealed that ligand biased signaling is exerted by the test compound (S)-5a. Starting from the D(3) crystal structure, a combination of homology modeling and site directed mutagenesis gave valuable insights into the binding mode and the intermolecular origins of stereospecific receptor recognition. According to these data, the superior affinity of the eutomer 5a is caused by the favorable binding energy that results from interaction between the ligand's central ammonium unit and the aspartate residue in position 3.32 of the receptor.
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Affiliation(s)
- Nuska Tschammer
- Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich Alexander University, Schuhstrasse 19, D-91052 Erlangen, Germany
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22
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Tschammer N, Bollinger S, Kenakin T, Gmeiner P. Histidine 6.55 is a major determinant of ligand-biased signaling in dopamine D2L receptor. Mol Pharmacol 2010; 79:575-85. [PMID: 21163968 DOI: 10.1124/mol.110.068106] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In our previous studies, we demonstrated that the mutation of His393(6.55) to alanine results in an increased affinity of 1,4-disubstituted phenylpiperazines to the dopamine D(2L) receptor. This change most likely accounts for the reduced steric hindrance in this part of the binding pocket. In this work, we investigated the role of the steric hindrance imposed by the residue His393(6.55) for the receptor activation modulated by 1,4-disubstituted aromatic piperidines/piperazines. Site-directed mutagenesis and ligand modifications were used to probe the structural basis of ligand efficacy. The operational model of agonism was used to quantify the ligand bias between the ability of compounds to inhibit cAMP accumulation and stimulate extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation. Whereas substantial ligand-biased signaling was observed for the D(2L) wild-type receptor, an overall increase in agonism was observed for the D(2L) H393(6.55)A mutant without noteworthy functional selectivity. Targeted chemical modification of the phenylpiperazine moiety at the site of its interaction with the residue His393(6.55) led to the functionally selective ligand {3-[4-(2,3-dihydro-benzofuran-7-yl)-piperazin-1-yl]-propyl}-pyrazol[1,5-a]pyridine-3-carboxamide (FAUC350) that has distinct signaling profiles toward adenylyl cyclase and ERK1/2. FAUC350 behaves as an antagonist in the inhibition of cAMP accumulation and as a partial agonist in the stimulation of ERK1/2 phosphorylation (efficacy = 55%). Overall, the residue His393(6.55) and proximate molecular substructures of receptor ligands were identified to be crucial for multidimensional ligand efficacy.
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Affiliation(s)
- Nuska Tschammer
- Department of Chemistry and Pharmacy, Friedrich Alexander University, Erlangen, Germany
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Skultety M, Hübner H, Löber S, Gmeiner P. Bioisosteric Replacement Leading to Biologically Active [2.2]Paracyclophanes with Altered Binding Profiles for Aminergic G-Protein-Coupled Receptors. J Med Chem 2010; 53:7219-28. [DOI: 10.1021/jm100899z] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Marika Skultety
- Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich Alexander University, Schuhstrasse 19, 91052 Erlangen, Germany
| | - Harald Hübner
- Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich Alexander University, Schuhstrasse 19, 91052 Erlangen, Germany
| | - Stefan Löber
- Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich Alexander University, Schuhstrasse 19, 91052 Erlangen, Germany
| | - Peter Gmeiner
- Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich Alexander University, Schuhstrasse 19, 91052 Erlangen, Germany
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