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Conrad M, Söldner CA, Sticht H. Effect of Ions and Sequence Variants on the Antagonist Binding Properties of the Histamine H 1 Receptor. Int J Mol Sci 2022; 23:ijms23031420. [PMID: 35163341 PMCID: PMC8836275 DOI: 10.3390/ijms23031420] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 01/14/2022] [Accepted: 01/18/2022] [Indexed: 11/16/2022] Open
Abstract
The histamine H1 receptor (H1R) is a G protein-coupled receptor (GPCR) and represents a main target in the treatment of allergic reactions as well as inflammatory reactions and depressions. Although the overall effect of antagonists on H1 function has been extensively investigated, rather little is known about the potential modulatory effect of ions or sequence variants on antagonist binding. We investigated the dynamics of a phosphate ion present in the crystal structure and of a sodium ion, for which we determined the position in the allosteric pocket by metadynamics simulations. Both types of ions exhibit significant dynamics within their binding site; however, some key contacts remain stable over the simulation time, which might be exploited to develop more potent drugs targeting these sites. The dynamics of the ions is almost unaffected by the presence or absence of doxepin, as also reflected in their small effect (less than 1 kcal·mol-1) on doxepin binding affinity. We also examined the effect of four H1R sequence variants observed in the human population on doxepin binding. These variants cause a reduction in doxepin affinity of up to 2.5 kcal·mol-1, indicating that personalized medical treatments that take into account individual mutation patterns could increase precision in the dosage of GPCR-targeting drugs.
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Affiliation(s)
- Marcus Conrad
- Division of Bioinformatics, Institute of Biochemistry, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (M.C.); (C.A.S.)
| | - Christian A. Söldner
- Division of Bioinformatics, Institute of Biochemistry, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (M.C.); (C.A.S.)
| | - Heinrich Sticht
- Division of Bioinformatics, Institute of Biochemistry, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (M.C.); (C.A.S.)
- Erlangen National High Performance Computing Center (NHR@FAU), Friedrich-Alexander-University Erlangen-Nürnberg (FAU), 91058 Erlangen, Germany
- Correspondence:
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Valle-Bautista R, Márquez-Valadez B, Herrera-López G, Griego E, Galván EJ, Díaz NF, Arias-Montaño JA, Molina-Hernández A. Long-Term Functional and Cytoarchitectonic Effects of the Systemic Administration of the Histamine H1 Receptor Antagonist/Inverse Agonist Chlorpheniramine During Gestation in the Rat Offspring Primary Motor Cortex. Front Neurosci 2022; 15:740282. [PMID: 35140581 PMCID: PMC8820484 DOI: 10.3389/fnins.2021.740282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 12/20/2021] [Indexed: 11/26/2022] Open
Abstract
The transient histaminergic system is among the first neurotransmitter systems to appear during brain development in the rat mesencephalon/rhombencephalon. Histamine increases FOXP2-positive deep-layer neuron differentiation of cortical neural stem cells through H1 receptor activation in vitro. The in utero or systemic administration of chlorpheniramine (H1 receptor antagonist/inverse agonist) during deep-layer cortical neurogenesis decreases FOXP2 neurons in the developing cortex, and H1R- or histidine decarboxylase-knockout mice show impairment in learning and memory, wakefulness and nociception, functions modulated by the cerebral cortex. Due to the role of H1R in cortical neural stem cell neurogenesis, the purpose of this study was to evaluate the postnatal impact of the systemic administration of chlorpheniramine during deep-layer cortical neuron differentiation (E12–14) in the primary motor cortex (M1) of neonates (P0) and 21-day-old pups (P21). Chlorpheniramine or vehicle were systemically administered (5 mg/kg, i.p.) to pregnant Wistar rats at gestational days 12–14, and the expression and distribution of deep- (FOXP2 and TBR1) and superficial-layer (SATB2) neuronal cortical markers were analyzed in neonates from both groups. The qRT-PCR analysis revealed a reduction in the expression of Satb2 and FoxP2. However, Western blot and immunofluorescence showed increased protein levels in the chlorpheniramine-treated group. In P21 pups, the three markers showed impaired distribution and increased immunofluorescence in the experimental group. The Sholl analysis evidenced altered dendritic arborization of deep-layer neurons, with lower excitability in response to histamine, as evaluated by whole-cell patch-clamp recording, as well as diminished depolarization-evoked [3H]-glutamate release from striatal slices. Overall, these results suggest long-lasting effects of blocking H1Rs during early neurogenesis that may impact the pathways involved in voluntary motor activity and cognition.
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Affiliation(s)
- Rocío Valle-Bautista
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Ciudad de México, Mexico
- Laboratorio de Investigación en Células Troncales y Biología del Desarrollo, Departamento de Fisiología y Desarrollo Celular, Subdirección de Investigación Biomédica, Instituto Nacional de Perinatología Isidro Espinosa de los Reyes, Ciudad de México, Mexico
| | - Berenice Márquez-Valadez
- Laboratorio de Investigación en Células Troncales y Biología del Desarrollo, Departamento de Fisiología y Desarrollo Celular, Subdirección de Investigación Biomédica, Instituto Nacional de Perinatología Isidro Espinosa de los Reyes, Ciudad de México, Mexico
| | - Gabriel Herrera-López
- Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Ciudad de México, Mexico
| | - Ernesto Griego
- Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Ciudad de México, Mexico
| | - Emilio J. Galván
- Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Ciudad de México, Mexico
| | - Néstor-Fabián Díaz
- Laboratorio de Investigación en Células Troncales y Biología del Desarrollo, Departamento de Fisiología y Desarrollo Celular, Subdirección de Investigación Biomédica, Instituto Nacional de Perinatología Isidro Espinosa de los Reyes, Ciudad de México, Mexico
| | - José-Antonio Arias-Montaño
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Ciudad de México, Mexico
| | - Anayansi Molina-Hernández
- Laboratorio de Investigación en Células Troncales y Biología del Desarrollo, Departamento de Fisiología y Desarrollo Celular, Subdirección de Investigación Biomédica, Instituto Nacional de Perinatología Isidro Espinosa de los Reyes, Ciudad de México, Mexico
- *Correspondence: Anayansi Molina-Hernández, ; orcid.org/0000-0002-4787-312X
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Kobayashi C, Tanaka A, Yasuda T, Hishinuma S. Roles of Lys191 and Lys179 in regulating thermodynamic binding forces of ligands to determine their binding affinity for human histamine H 1 receptors. Biochem Pharmacol 2020; 180:114185. [PMID: 32738199 DOI: 10.1016/j.bcp.2020.114185] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 07/27/2020] [Accepted: 07/27/2020] [Indexed: 12/23/2022]
Abstract
Docking simulations based on the crystal structure of human histamine H1 receptors have predicted crucial roles of Lys1915.39 and Lys179ECL2, which exist at the entrance of the ligand-binding pocket, in increasing the H1-receptor selectivity for carboxylated second-generation antihistamines via electrostatic interaction. In this study, we evaluated the roles of Lys1915.39 and Lys179ECL2 in regulating the thermodynamic binding forces of non-carboxylated and carboxylated antihistamines that determine their binding affinity for human H1 receptors. The binding enthalpy and entropy of the 3 sets of non-carboxylated and corresponding carboxylated antihistamines (doxepin and olopatadine, desloratadine and loratadine, and terfenadine and fexofenadine, respectively) were estimated using the van't Hoff equation with the dissociation constants obtained from the displacement curves of the non-carboxylated and carboxylated antihistamines against the binding of [3H]mepyramine to the membrane preparations of Chinese hamster ovary cells expressing human H1 receptors at various temperatures, ranging from 4 °C to 37 °C. We found that the affinity for carboxylated antihistamines was lower than that for the corresponding non-carboxylated compounds due to lower enthalpy-dependent electrostatic binding forces and/or entropy-dependent hydrophobic binding forces. Mutations of Lys1915.39 and/or Lys179ECL2 to alanine mostly increased the binding affinity for antihistamines due to a variety of changes in both enthalpy- and entropy-dependent binding forces. These results suggest that Lys1915.39 and Lys179ECL2 may not contribute to selectively increasing the binding affinity for carboxylated antihistamines via electrostatic interaction, but that they can negatively modulate the binding affinity for non-carboxylated and carboxylated antihistamines non-selectively by affecting their electrostatic as well as hydrophobic binding forces.
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Affiliation(s)
- Chihiro Kobayashi
- Department of Pharmacodynamics, Meiji Pharmaceutical University, 2-522-1 Kiyose, Tokyo 204-8588, Japan
| | - Airi Tanaka
- Department of Pharmacodynamics, Meiji Pharmaceutical University, 2-522-1 Kiyose, Tokyo 204-8588, Japan
| | - Tomomi Yasuda
- Department of Pharmacodynamics, Meiji Pharmaceutical University, 2-522-1 Kiyose, Tokyo 204-8588, Japan
| | - Shigeru Hishinuma
- Department of Pharmacodynamics, Meiji Pharmaceutical University, 2-522-1 Kiyose, Tokyo 204-8588, Japan.
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Distinct binding of cetirizine enantiomers to human serum albumin and the human histamine receptor H 1. J Comput Aided Mol Des 2020; 34:1045-1062. [PMID: 32572668 DOI: 10.1007/s10822-020-00328-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Accepted: 06/18/2020] [Indexed: 02/02/2023]
Abstract
Cetirizine, a major metabolite of hydroxyzine, became a marketed second-generation H1 antihistamine that is orally active and has a rapid onset of action, long duration of effects and a very good safety record at recommended doses. The approved drug is a racemic mixture of (S)-cetirizine and (R)-cetirizine, the latter being the levorotary enantiomer that also exists in the market as a third-generation, non-sedating and highly selective antihistamine. Both enantiomers bind tightly to the human histamine H1 receptor (hH1R) and behave as inverse agonists but the affinity and residence time of (R)-cetirizine are greater than those of (S)-cetirizine. In blood plasma, cetirizine exists in the zwitterionic form and more than 90% of the circulating drug is bound to human serum albumin (HSA), which acts as an inactive reservoir. Independent X-ray crystallographic work has solved the structure of the hH1R:doxepin complex and has identified two drug-binding sites for cetirizine on equine serum albumin (ESA). Given this background, we decided to model a membrane-embedded hH1R in complex with either (R)- or (S)-cetirizine and also the complexes of both ESA and HSA with these two enantiomeric drugs to analyze possible differences in binding modes between enantiomers and also among targets. The ensuing molecular dynamics simulations in explicit solvent and additional computational chemistry calculations provided structural and energetic information about all of these complexes that is normally beyond current experimental possibilities. Overall, we found very good agreement between our binding energy estimates and extant biochemical and pharmacological evidence. A much higher degree of solvent exposure in the cetirizine-binding site(s) of HSA and ESA relative to the more occluded orthosteric binding site in hH1R is translated into larger positional fluctuations and considerably lower affinities for these two nonspecific targets. Whereas it is demonstrated that the two known pockets in ESA provide enough stability for cetirizine binding, only one such site does so in HSA due to a number of amino acid replacements. At the histamine-binding site in hH1R, the distinct interactions established between the phenyl and chlorophenyl moieties of the two enantiomers with the amino acids lining up the pocket and between their free carboxylates and Lys179 in the second extracellular loop account for the improved pharmacological profile of (R)-cetirizine.
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Zarzycka B, Zaidi SA, Roth BL, Katritch V. Harnessing Ion-Binding Sites for GPCR Pharmacology. Pharmacol Rev 2019; 71:571-595. [PMID: 31551350 PMCID: PMC6782022 DOI: 10.1124/pr.119.017863] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Endogenous ions play important roles in the function and pharmacology of G-protein coupled receptors (GPCRs). Historically the evidence for ionic modulation of GPCR function dates to 1973 with studies of opioid receptors, where it was demonstrated that physiologic concentrations of sodium allosterically attenuated agonist binding. This Na+-selective effect was distinct from effects of other monovalent and divalent cations, with the latter usually counteracting sodium's negative allosteric modulation of binding. Since then, numerous studies documenting the effects of mono- and divalent ions on GPCR function have been published. While ions can act selectively and nonselectively at many sites in different receptors, the discovery of the conserved sodium ion site in class A GPCR structures in 2012 revealed the unique nature of Na+ site, which has emerged as a near-universal site for allosteric modulation of class A GPCR structure and function. In this review, we synthesize and highlight recent advances in the functional, biophysical, and structural characterization of ions bound to GPCRs. Taken together, these findings provide a molecular understanding of the unique roles of Na+ and other ions as GPCR allosteric modulators. We will also discuss how this knowledge can be applied to the redesign of receptors and ligand probes for desired functional and pharmacological profiles. SIGNIFICANCE STATEMENT: The function and pharmacology of GPCRs strongly depend on the presence of mono and divalent ions in experimental assays and in living organisms. Recent insights into the molecular mechanism of this ion-dependent allosterism from structural, biophysical, biochemical, and computational studies provide quantitative understandings of the pharmacological effects of drugs in vitro and in vivo and open new avenues for the rational design of chemical probes and drug candidates with improved properties.
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Affiliation(s)
- Barbara Zarzycka
- Departments of Biological Sciences (B.Z., S.A.Z., V.K.) and Chemistry (V.K.), Bridge Institute, Michelson Center for Convergent Bioscience, University of Southern California, Los Angeles, California; and Department of Pharmacology (B.L.R.) and Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy (B.L.R.), University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Saheem A Zaidi
- Departments of Biological Sciences (B.Z., S.A.Z., V.K.) and Chemistry (V.K.), Bridge Institute, Michelson Center for Convergent Bioscience, University of Southern California, Los Angeles, California; and Department of Pharmacology (B.L.R.) and Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy (B.L.R.), University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Bryan L Roth
- Departments of Biological Sciences (B.Z., S.A.Z., V.K.) and Chemistry (V.K.), Bridge Institute, Michelson Center for Convergent Bioscience, University of Southern California, Los Angeles, California; and Department of Pharmacology (B.L.R.) and Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy (B.L.R.), University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Vsevolod Katritch
- Departments of Biological Sciences (B.Z., S.A.Z., V.K.) and Chemistry (V.K.), Bridge Institute, Michelson Center for Convergent Bioscience, University of Southern California, Los Angeles, California; and Department of Pharmacology (B.L.R.) and Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy (B.L.R.), University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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Márquez-Valadez B, Aquino-Miranda G, Quintero-Romero MO, Papacostas-Quintanilla H, Bueno-Nava A, López-Rubalcava C, Díaz NF, Arias-Montaño JA, Molina-Hernández A. The Systemic Administration of the Histamine H 1 Receptor Antagonist/Inverse Agonist Chlorpheniramine to Pregnant Rats Impairs the Development of Nigro-Striatal Dopaminergic Neurons. Front Neurosci 2019; 13:360. [PMID: 31040765 PMCID: PMC6476962 DOI: 10.3389/fnins.2019.00360] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 03/29/2019] [Indexed: 11/13/2022] Open
Abstract
The dopaminergic and histaminergic systems are the first to appear during the development of the nervous system. Through the activation of H1 receptors (H1Rs), histamine increases neurogenesis of the cortical deep layers, while reducing the dopaminergic phenotype (cells immunoreactive to tyrosine hydroxylase, TH+) in embryo ventral mesencephalon. Although the function of histamine in neuronal differentiation has been studied, the role of H1Rs in neurogenesis has not been addressed. For this purpose, the H1R antagonist/inverse agonist chlorpheniramine was systemically administered (5 mg/kg, i.p.) to pregnant Wistar rats (gestational days 12-14, E12-14), and control and experimental embryos (E14 and E16) and pups (21-day-old) were evaluated for changes in nigro-striatal development. Western blot and immunohistochemistry determinations showed a significant increase in the dopaminergic markers' TH and PITX3 in embryos from chlorpheniramine-treated rats at E16. Unexpectedly, 21-day-old pups from the chlorpheniramine-treated group, showed a significant reduction in TH immunoreactivity in the substantia nigra pars compacta and dorsal striatum. Furthermore, striatal dopamine content, evoked [3H]-dopamine release and methamphetamine-stimulated motor activity were significantly lower compared to the control group. These results indicate that H1R blockade at E14-E16 favors the differentiation of dopaminergic neurons, but hampers their migration, leading to a decrease in dopaminergic innervation of the striatum in post-natal life.
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Affiliation(s)
- Berenice Márquez-Valadez
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico.,Laboratorio de Investigación en Células Troncales y Biología del Desarrollo, Departamento de Fisiología y Desarrollo Celular, Instituto Nacional de Perinatología Isidro Espinosa de los Reyes, Mexico City, Mexico
| | - Guillermo Aquino-Miranda
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Mijail-Oliver Quintero-Romero
- Laboratorio de Investigación en Células Troncales y Biología del Desarrollo, Departamento de Fisiología y Desarrollo Celular, Instituto Nacional de Perinatología Isidro Espinosa de los Reyes, Mexico City, Mexico
| | - Helena Papacostas-Quintanilla
- Laboratorio de Psicofarmacología y Trastornos de la Alimentación, Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados delInstituto Politécnico Nacional, Mexico City, Mexico
| | - Antonio Bueno-Nava
- División de Neurociencias, Instituto Nacional de Rehabilitación Luis Guillermo Ibarra Ibarra, Mexico City, Mexico
| | - Carolina López-Rubalcava
- Laboratorio de Psicofarmacología y Trastornos de la Alimentación, Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados delInstituto Politécnico Nacional, Mexico City, Mexico
| | - Néstor Fabián Díaz
- Laboratorio de Investigación en Células Troncales y Biología del Desarrollo, Departamento de Fisiología y Desarrollo Celular, Instituto Nacional de Perinatología Isidro Espinosa de los Reyes, Mexico City, Mexico
| | - José-Antonio Arias-Montaño
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Anayansi Molina-Hernández
- Laboratorio de Investigación en Células Troncales y Biología del Desarrollo, Departamento de Fisiología y Desarrollo Celular, Instituto Nacional de Perinatología Isidro Espinosa de los Reyes, Mexico City, Mexico
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7
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Hishinuma S, Tamura Y, Kobayashi C, Akatsu C, Shoji M. Differential Regulation of Thermodynamic Binding Forces of Levocetirizine and ( S)-Cetirizine by Lys191 in Human Histamine H₁ Receptors. Int J Mol Sci 2018; 19:ijms19124067. [PMID: 30558340 PMCID: PMC6321019 DOI: 10.3390/ijms19124067] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 12/12/2018] [Accepted: 12/13/2018] [Indexed: 01/24/2023] Open
Abstract
Cetirizine is a zwitterionic second-generation antihistamine containing R- and S-enantiomers, levocetirizine, and (S)-cetirizine. Levocetirizine is known to have a higher affinity for the histamine H₁ receptors than (S)-cetirizine; ligand-receptor docking simulations have suggested the importance of the formation of a salt bridge (electrostatic interaction) between the carboxylic group of levocetirizine and the Lys191 residue at the fifth transmembrane domain of human histamine H₁ receptors. In this study, we evaluated the roles of Lys191 in the regulation of the thermodynamic binding forces of levocetirizine in comparison with (S)-cetirizine. The binding enthalpy and entropy of these compounds were estimated from the van 't Hoff equation, by using the dissociation constants obtained from their displacement curves against the binding of [³H]mepyramine to the membrane preparations of Chinese hamster ovary cells expressing wild-type human H₁ receptors and their Lys191 mutants to alanine at various temperatures. We found that the higher binding affinity of wild-type H₁ receptors for levocetirizine than (S)-cetirizine was achieved by stronger forces of entropy-dependent hydrophobic binding of levocetirizine. The mutation of Lys191 to alanine reduced the affinities for levocetirizine and (S)-cetirizine, through a reduction in the entropy-dependent hydrophobic binding forces of levocetirizine and the enthalpy-dependent electrostatic binding forces of (S)-cetirizine. These results suggested that Lys191 differentially regulates the binding enthalpy and entropy of these enantiomers, and that Lys191 negatively regulates the enthalpy-dependent electrostatic binding forces of levocetirizine, contrary to the predictions derived from the ligand-receptor docking simulations.
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Affiliation(s)
- Shigeru Hishinuma
- Department of Pharmacodynamics, Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose, Tokyo 204-8588, Japan.
| | - Yuri Tamura
- Department of Pharmacodynamics, Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose, Tokyo 204-8588, Japan.
| | - Chihiro Kobayashi
- Department of Pharmacodynamics, Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose, Tokyo 204-8588, Japan.
| | - Chizuru Akatsu
- Department of Pharmacodynamics, Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose, Tokyo 204-8588, Japan.
| | - Masaru Shoji
- Department of Pharmacodynamics, Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose, Tokyo 204-8588, Japan.
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8
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Mocking TAM, Verweij EWE, Vischer HF, Leurs R. Homogeneous, Real-Time NanoBRET Binding Assays for the Histamine H 3 and H 4 Receptors on Living Cells. Mol Pharmacol 2018; 94:1371-1381. [PMID: 30249614 DOI: 10.1124/mol.118.113373] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 09/19/2018] [Indexed: 11/22/2022] Open
Abstract
Receptor-binding affinity and ligand-receptor residence time are key parameters for the selection of drug candidates and are routinely determined using radioligand competition-binding assays. Recently, a novel bioluminescence resonance energy transfer (BRET) method utilizing a NanoLuc-fused receptor was introduced to detect fluorescent ligand binding. Moreover, this NanoBRET method gives the opportunity to follow fluorescent ligand binding on intact cells in real time, and therefore, results might better reflect in vivo conditions as compared with the routinely used cell homogenates or purified membrane fractions. In this study, a real-time NanoBRET-based binding assay was established and validated to detect binding of unlabeled ligands to the histamine H3 receptor (H3R) and histamine H4 receptor on intact cells. Obtained residence times of clinically tested H3R antagonists were reflected by their duration of H3R antagonism in a functional receptor recovery assay.
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Affiliation(s)
- Tamara A M Mocking
- Amsterdam Institute for Molecules, Medicines and Systems, Division of Medicinal Chemistry, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Eléonore W E Verweij
- Amsterdam Institute for Molecules, Medicines and Systems, Division of Medicinal Chemistry, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Henry F Vischer
- Amsterdam Institute for Molecules, Medicines and Systems, Division of Medicinal Chemistry, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Rob Leurs
- Amsterdam Institute for Molecules, Medicines and Systems, Division of Medicinal Chemistry, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
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9
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Schiffmann A, Gimpl G. Sodium functions as a negative allosteric modulator of the oxytocin receptor. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018. [PMID: 29524392 DOI: 10.1016/j.bbamem.2018.03.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The oxytocin receptor, a class A G protein coupled receptor (GPCR), is essentially involved in the physiology of reproduction. Two parameters are crucially important to support high-affinity agonist binding of the receptor: Mg2+ and cholesterol, both acting as positive modulators. Using displacement assays with a high-affinity fluorescent antagonist (OTAN-A647), we now show that sodium functions as a negative allosteric modulator of the oxytocin receptor. In membranes from HEK293 cells stably expressing the oxytocin receptor, oxytocin binding occurred with about 15-fold lower affinity when sodium chloride was increased from 0 to 300 mM, whereas antagonist binding remained largely unchanged. The effect was concentration-dependent, sodium-specific, and it was also observed for oxytocin receptors endogenously expressed in Hs578T breast cancer cells. A conserved Asp (Asp 85) is known to stabilize the sodium binding site in other GCPRs. Mutations of this residue into Ala or Asn are known to yield non-functional oxytocin receptors. When Asp 85 was exchanged for Glu, most of the oxytocin receptors were localized in intracellular structures, but a faint plasma membrane labeling with OTAN-A647 and the appearance of oxytocin-induced calcium responses indicated that these receptors were functional. However, a sodium effect was not detectable for the mutant D85E oxytocin receptors. Thus, the oxytocin receptor is allosterically controlled by sodium similar to other GPCRs, but it behaves differently concerning the involvement of the conserved Asp 85. In case of the oxytocin receptor, Asp 85 is obviously essential for proper localization in the plasma membrane.
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Affiliation(s)
- Andrea Schiffmann
- Johannes-Gutenberg University Mainz, Institute of Biochemistry, Johann-Joachim Becherweg 30, 55128 Mainz, Germany
| | - Gerald Gimpl
- Johannes-Gutenberg University Mainz, Institute of Biochemistry, Johann-Joachim Becherweg 30, 55128 Mainz, Germany.
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White KL, Eddy MT, Gao ZG, Han GW, Lian T, Deary A, Patel N, Jacobson KA, Katritch V, Stevens RC. Structural Connection between Activation Microswitch and Allosteric Sodium Site in GPCR Signaling. Structure 2018; 26:259-269.e5. [PMID: 29395784 DOI: 10.1016/j.str.2017.12.013] [Citation(s) in RCA: 109] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 11/21/2017] [Accepted: 12/27/2017] [Indexed: 12/18/2022]
Abstract
Sodium ions are endogenous allosteric modulators of many G-protein-coupled receptors (GPCRs). Mutation of key residues in the sodium binding motif causes a striking effect on G-protein signaling. We report the crystal structures of agonist complexes for two variants in the first sodium coordination shell of the human A2A adenosine receptor, D522.50N and S913.39A. Both structures present an overall active-like conformation; however, the variants show key changes in the activation motif NPxxY. Changes in the hydrogen bonding network in this microswitch suggest a possible mechanism for modified G-protein signaling and enhanced thermal stability. These structures, signaling data, and thermal stability analysis with a panel of pharmacological ligands provide a basis for understanding the role of the sodium-coordinating residues on stability and G-protein signaling. Utilizing the D2.50N variant is a promising method for stabilizing class A GPCRs to accelerate structural efforts and drug discovery.
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Affiliation(s)
- Kate L White
- Departments of Biological Sciences and Chemistry, Bridge Institute, USC Michelson Center, University of Southern California, 1002 West Childs Way, Los Angeles, CA 90089, USA
| | - Matthew T Eddy
- Departments of Biological Sciences and Chemistry, Bridge Institute, USC Michelson Center, University of Southern California, 1002 West Childs Way, Los Angeles, CA 90089, USA
| | - Zhan-Guo Gao
- Laboratory of Bioorganic Chemistry, NIDDK, National Institutes of Health, Bethesda, MD 20892, USA
| | - Gye Won Han
- Departments of Biological Sciences and Chemistry, Bridge Institute, USC Michelson Center, University of Southern California, 1002 West Childs Way, Los Angeles, CA 90089, USA
| | - Tiffany Lian
- Departments of Biological Sciences and Chemistry, Bridge Institute, USC Michelson Center, University of Southern California, 1002 West Childs Way, Los Angeles, CA 90089, USA
| | - Alexander Deary
- Departments of Biological Sciences and Chemistry, Bridge Institute, USC Michelson Center, University of Southern California, 1002 West Childs Way, Los Angeles, CA 90089, USA
| | - Nilkanth Patel
- Departments of Biological Sciences and Chemistry, Bridge Institute, USC Michelson Center, University of Southern California, 1002 West Childs Way, Los Angeles, CA 90089, USA
| | - Kenneth A Jacobson
- Laboratory of Bioorganic Chemistry, NIDDK, National Institutes of Health, Bethesda, MD 20892, USA
| | - Vsevolod Katritch
- Departments of Biological Sciences and Chemistry, Bridge Institute, USC Michelson Center, University of Southern California, 1002 West Childs Way, Los Angeles, CA 90089, USA
| | - Raymond C Stevens
- Departments of Biological Sciences and Chemistry, Bridge Institute, USC Michelson Center, University of Southern California, 1002 West Childs Way, Los Angeles, CA 90089, USA.
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