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Sander BP. Prevention of Choroidal Thinning by 0.01% Atropine Administered 24 h Before Exposure to Hyperopic Blur in Young Myopes. J Ocul Pharmacol Ther 2021; 37:510-517. [PMID: 34491840 DOI: 10.1089/jop.2021.0006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Purpose: To evaluate the persistence of atropine's effect upon choroidal thickness and ocular biometrics and its interaction with hyperopic blur in a population of young adult myopes. Methods: Twenty young (aged 18-35 years) myopic participants with spherical equivalent refractive error of -0.75 to -6.00 D (mean ± SD -2.85 ± 1.64 D) had subfoveal choroidal thickness (SFCT) measurements derived from scans collected from the right eye only with a SD-OCT instrument (Copernicus SOCT-HR) before, as well as 60 min following the introduction of 3 testing conditions: (1) placebo/hyperopic (-3 D) blur, (2) placebo/hyperopic blur one day after administration of 0.01% atropine, and (3) placebo/no blur. Each combination of blur and pharmacological agent was tested on a separate day at approximately the same time of day between 9 am and 2 pm. Results: Repeated measures ANOVA revealed that hyperopic blur and placebo were associated with a decrease in choroidal thickness (mean change: -10.7 ± 2.7 μm, P < 0.001 after 60 min), whereas administration of 0.01% atropine one day before the introduction of hyperopic blur prevented the thinning of the choroid (mean change of +1.1 ± 3.7 μm after 60 min) compared to baseline (both, P > 0.05). There was also no significant difference between the baseline choroidal thickness measurements for any of the conditions tested. Conclusion: Low dose atropine can inhibit signals associated with hyperopic defocus that cause thinning of the choroid for at least 24 h after initial instillation.
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Affiliation(s)
- Beata P Sander
- Contact Lens and Visual Optics Laboratory, School of Optometry and Vision Science, Queensland University of Technology, Brisbane, Australia.,Lees and Henschell Optometrists, Kenmore, Australia
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Dinter J, Khajavi N, Mühlhaus J, Wienchol CL, Cöster M, Hermsdorf T, Stäubert C, Köhrle J, Schöneberg T, Kleinau G, Mergler S, Biebermann H. The Multitarget Ligand 3-Iodothyronamine Modulates β-Adrenergic Receptor 2 Signaling. Eur Thyroid J 2015; 4:21-9. [PMID: 26601070 PMCID: PMC4640289 DOI: 10.1159/000381801] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 03/19/2015] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND 3-Iodothyronamine (3-T1AM), a signaling molecule with structural similarities to thyroid hormones, induces numerous physiological responses including reversible body temperature decline. One target of 3-T1AM is the trace amine-associated receptor 1 (TAAR1), which is a member of the rhodopsin-like family of G protein-coupled receptors (GPCRs). Interestingly, the effects of 3-T1AM remain detectable in TAAR1 knockout mice, suggesting further targets for 3-T1AM such as adrenergic receptors. Therefore, we evaluated whether β-adrenergic receptor 1 (ADRB1) and 2 (ADRB2) signaling is affected by 3-T1AM in HEK293 cells and in human conjunctival epithelial cells (IOBA-NHC), where these receptors are highly expressed endogenously. METHODS A label-free EPIC system for prescreening the 3-T1AM-induced effects on ADRB1 and ADRB2 in transfected HEK293 cells was used. In addition, ADRB1 and ADRB2 activation was analyzed using a cyclic AMP assay and a MAPK reporter gene assay. Finally, fluorescence Ca(2+) imaging was utilized to delineate 3-T1AM-induced Ca(2+) signaling. RESULTS 3-T1AM (10(-5)-10(-10)M) enhanced isoprenaline-induced ADRB2-mediated Gs signaling but not that of ADRB1-mediated signaling. MAPK signaling remained unaffected for both receptors. In IOBA-NHC cells, norepinephrine-induced Ca(2+) influxes were blocked by the nonselective ADRB blocker timolol (10 µM), indicating that ADRBs are most likely linked with Ca(2+) channels. Notably, timolol was also found to block 3-T1AM (10(-5)M)-induced Ca(2+) influx. CONCLUSIONS The presented data support that 3-T1AM directly modulates β-adrenergic receptor signaling. The relationship between 3-T1AM and β-adrenergic signaling also reveals a potential therapeutic value for suppressing Ca(2+) channel-mediated inflammation processes, occurring in eye diseases such as conjunctivitis.
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Affiliation(s)
- Juliane Dinter
- Institut für Experimentelle Pädiatrische Endokrinologie, Berlin, Germany
| | - Noushafarin Khajavi
- Department of Ophthalmology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Jessica Mühlhaus
- Institut für Experimentelle Pädiatrische Endokrinologie, Berlin, Germany
| | | | - Maxi Cöster
- Institut für Biochemie, Molekulare Biochemie, Medizinische Fakultät, University of Leipzig, Leipzig, Germany
| | - Thomas Hermsdorf
- Institut für Biochemie, Molekulare Biochemie, Medizinische Fakultät, University of Leipzig, Leipzig, Germany
| | - Claudia Stäubert
- Institut für Biochemie, Molekulare Biochemie, Medizinische Fakultät, University of Leipzig, Leipzig, Germany
| | - Josef Köhrle
- Institut für Experimentelle Endokrinologie, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Torsten Schöneberg
- Institut für Biochemie, Molekulare Biochemie, Medizinische Fakultät, University of Leipzig, Leipzig, Germany
| | - Gunnar Kleinau
- Institut für Experimentelle Pädiatrische Endokrinologie, Berlin, Germany
| | - Stefan Mergler
- Department of Ophthalmology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Heike Biebermann
- Institut für Experimentelle Pädiatrische Endokrinologie, Berlin, Germany
- *Heike Biebermann, Institut für Experimentelle Pädiatrische Endokrinologie, Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, DE-13353 Berlin (Germany), E-Mail , Stefan Mergler, Department of Ophthalmology, Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, DE-13353 Berlin (Germany), E-Mail
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Stäubert C, Le Duc D, Schöneberg T. Examining the Dynamic Evolution of G Protein-Coupled Receptors. METHODS IN PHARMACOLOGY AND TOXICOLOGY 2014. [DOI: 10.1007/978-1-62703-779-2_2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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Thimm D, Funke M, Meyer A, Müller CE. 6-Bromo-8-(4-[3H]methoxybenzamido)-4-oxo-4H-chromene-2-carboxylic Acid: A Powerful Tool for Studying Orphan G Protein-Coupled Receptor GPR35. J Med Chem 2013; 56:7084-99. [DOI: 10.1021/jm4009373] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dominik Thimm
- PharmaCenter Bonn, Pharmaceutical
Institute, Pharmaceutical
Chemistry I, University of Bonn, An der
Immenburg 4, D-53121 Bonn, Germany
| | - Mario Funke
- PharmaCenter Bonn, Pharmaceutical
Institute, Pharmaceutical
Chemistry I, University of Bonn, An der
Immenburg 4, D-53121 Bonn, Germany
| | - Anne Meyer
- PharmaCenter Bonn, Pharmaceutical
Institute, Pharmaceutical
Chemistry I, University of Bonn, An der
Immenburg 4, D-53121 Bonn, Germany
| | - Christa E. Müller
- PharmaCenter Bonn, Pharmaceutical
Institute, Pharmaceutical
Chemistry I, University of Bonn, An der
Immenburg 4, D-53121 Bonn, Germany
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Schmidt P, Ritscher L, Dong EN, Hermsdorf T, Cöster M, Wittkopf D, Meiler J, Schöneberg T. Identification of determinants required for agonistic and inverse agonistic ligand properties at the ADP receptor P2Y12. Mol Pharmacol 2012; 83:256-66. [PMID: 23093496 DOI: 10.1124/mol.112.082198] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The ADP receptor P2Y(12) belongs to the superfamily of G protein-coupled receptors (GPCRs), and its activation triggers platelet aggregation. Therefore, potent antagonists, such as clopidogrel, are of high clinical relevance in prophylaxis and treatment of thromboembolic events. P2Y(12) displays an elevated basal activity in vitro, and as such, inverse agonists may be therapeutically beneficial compared with antagonists. Only a few inverse agonists of P2Y(12) have been described. To expand this limited chemical space and improve understanding of structural determinants of inverse agonist-receptor interaction, this study screened a purine compound library for lead structures using wild-type (WT) human P2Y(12) and 28 constitutively active mutants. Results showed that ATP and ATP derivatives are agonists at P2Y(12). The potency at P2Y(12) was 2-(methylthio)-ADP > 2-(methylthio)-ATP > ADP > ATP. Determinants required for agonistic ligand activity were identified. Molecular docking studies revealed a binding pocket for the ATP derivatives that is bordered by transmembrane helices 3, 5, 6, and 7 in human P2Y(12,) with Y(105), E(188), R(256), Y(259), and K(280) playing a particularly important role in ligand interaction. N-Methyl-anthraniloyl modification at the 3'-OH of the 2'-deoxyribose leads to ligands (mant-deoxy-ATP [dATP], mant-deoxy-ADP) with inverse agonist activity. Inverse agonist activity of mant-dATP was found at the WT human P2Y(12) and half of the constitutive active P2Y(12) mutants. This study showed that, in addition to ADP and ATP, other ATP derivatives are not only ligands of P2Y(12) but also agonists. Modification of the ribose within ATP can result in inverse activity of ATP-derived ligands.
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Affiliation(s)
- Philipp Schmidt
- Institute of Biochemistry, Molecular Biochemistry, Johannisallee 30, 04103 Leipzig, Germany
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Abstract
Lyso-PS (lyso-phosphatidylserine) has been shown to activate the G(i/o)-protein-coupled receptor GPR34. Since in vitro and in vivo studies provided controversial results in assigning lyso-PS as the endogenous agonist for GPR34, we investigated the evolutionary conservation of agonist specificity in more detail. Except for some fish GPR34 subtypes, lyso-PS has no or very weak agonistic activity at most vertebrate GPR34 orthologues investigated. Using chimaeras we identified single positions in the second extracellular loop and the transmembrane helix 5 of carp subtype 2a that, if transferred to the human orthologue, enabled lyso-PS to activate the human GPR34. Significant improvement of agonist efficacy by changing only a few positions strongly argues against the hypothesis that nature optimized GPR34 as the receptor for lyso-PS. Phylogenetic analysis revealed several positions in some fish GPR34 orthologues which are under positive selection. These structural changes may indicate functional specification of these orthologues which can explain the species- and subtype-specific pharmacology of lyso-PS. Furthermore, we identified aminoethyl-carbamoyl ATP as an antagonist of carp GPR34, indicating ligand promiscuity with non-lipid compounds. The results of the present study suggest that lyso-PS has only a random agonistic activity at some GPR34 orthologues and the search for the endogenous agonist should consider additional chemical entities.
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Cöster M, Wittkopf D, Kreuchwig A, Kleinau G, Thor D, Krause G, Schöneberg T. Using ortholog sequence data to predict the functional relevance of mutations in G‐protein‐coupled receptors. FASEB J 2012; 26:3273-81. [DOI: 10.1096/fj.12-203737] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Maxi Cöster
- Molecular Biochemistry, Institute of Biochemistry, Medical FacultyUniversity of Leipzig Leipzig Germany
| | - Doreen Wittkopf
- Molecular Biochemistry, Institute of Biochemistry, Medical FacultyUniversity of Leipzig Leipzig Germany
| | | | - Gunnar Kleinau
- Institute of Experimental Pediatric EndocrinologyCharité Universitätsmedizin Berlin Berlin Germany
| | - Doreen Thor
- Molecular Biochemistry, Institute of Biochemistry, Medical FacultyUniversity of Leipzig Leipzig Germany
| | - Gerd Krause
- Leibniz Institute for Molecular Pharmacology Berlin Germany
| | - Torsten Schöneberg
- Molecular Biochemistry, Institute of Biochemistry, Medical FacultyUniversity of Leipzig Leipzig Germany
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Liebscher I, Müller U, Teupser D, Engemaier E, Engel KMY, Ritscher L, Thor D, Sangkuhl K, Ricken A, Wurm A, Piehler D, Schmutzler S, Fuhrmann H, Albert FW, Reichenbach A, Thiery J, Schöneberg T, Schulz A. Altered immune response in mice deficient for the G protein-coupled receptor GPR34. J Biol Chem 2010; 286:2101-10. [PMID: 21097509 DOI: 10.1074/jbc.m110.196659] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The X-chromosomal GPR34 gene encodes an orphan G(i) protein-coupled receptor that is highly conserved among vertebrates. To evaluate the physiological relevance of GPR34, we generated a GPR34-deficient mouse line. GPR34-deficient mice were vital, reproduced normally, and showed no gross abnormalities in anatomical, histological, laboratory chemistry, or behavioral investigations under standard housing. Because GPR34 is highly expressed in mononuclear cells of the immune system, mice were specifically tested for altered functions of these cell types. Following immunization with methylated BSA, the number of granulocytes and macrophages in spleens was significantly lower in GPR34-deficient mice as in wild-type mice. GPR34-deficient mice showed significantly increased paw swelling in the delayed type hypersensitivity test and higher pathogen burden in extrapulmonary tissues after pulmonary infection with Cryptococcus neoformans compared with wild-type mice. The findings in delayed type hypersensitivity and infection tests were accompanied by significantly different basal and stimulated TNF-α, GM-CSF, and IFN-γ levels in GPR34-deficient animals. Our data point toward a functional role of GPR34 in the cellular response to immunological challenges.
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Affiliation(s)
- Ines Liebscher
- Institute of Biochemistry, Medical Faculty, University Leipzig, 04103 Leipzig, Germany
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Stewart GD, Sexton PM, Christopoulos A. Detection of novel functional selectivity at M3 muscarinic acetylcholine receptors using a Saccharomyces cerevisiae platform. ACS Chem Biol 2010; 5:365-75. [PMID: 20155933 DOI: 10.1021/cb900276p] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
"Functional selectivity", although new to many chemists and biologists only a few years ago, has now become a dominant theme in drug discovery. This concept posits that different ligands engender unique receptor conformations such that only a subset of signaling pathways linked to a given receptor are recruited. However, successful exploitation of the phenomenon to achieve pathway-based selectivity requires the ability to routinely detect it when assessing ligand behavior. We have utilized different strains of the yeast S. cerevisiae, each expressing a specific human Galpha/yeast Gpa1 protein chimera coupled to a MAP kinase-linked reporter gene readout, to investigate the signaling of the M(3) muscarinic receptor, a G protein-coupled receptor (GPCR) for which various antagonists are used clinically. Using this novel platform, we found that the "antagonists", atropine, N-methylscopolamine, and pirenzepine, were inverse agonists for Gpa1/Galpha(q) but low efficacy agonists for Gpa1/Galpha(12.) Subsequent studies with atropine performed in mammalian 3T3 cells validated these findings by demonstrating inverse agonism for G(q/11)-mediated calcium mobilization but positive agonism for G(12)-mediated membrane ruffling. This is the first study to utilize a yeast platform to discover pathway-biased functional selectivity in a GPCR. In addition to the likely applicability of this approach for identifying biased signaling by novel chemical entities, our findings also suggest that currently marketed medications may exhibit hitherto unappreciated functional selectivity.
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Affiliation(s)
- Gregory D. Stewart
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences & Department of Pharmacology, Monash University, Parkville, Victoria, Australia 3052
| | - Patrick M. Sexton
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences & Department of Pharmacology, Monash University, Parkville, Victoria, Australia 3052
| | - Arthur Christopoulos
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences & Department of Pharmacology, Monash University, Parkville, Victoria, Australia 3052
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Noetzel MJ, Grant MKO, El-Fakahany EE. Mechanisms of M3 muscarinic receptor regulation by wash-resistant xanomeline binding. Pharmacology 2009; 83:301-17. [PMID: 19401618 DOI: 10.1159/000214843] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2008] [Accepted: 02/12/2009] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIMS Xanomeline has been shown to bind in a unique manner at M1 and M3 muscarinic receptors, with interactions at both the orthosteric site and an allosteric site. We have previously shown that brief exposure of Chinese hamster ovary cells that express the M3 receptor to xanomeline followed by removal of free agonist results in a delayed decrease in radioligand binding and receptor response to agonists. In the current study, we were interested in determining the mechanisms of this effect. METHODS Cells were treated with carbachol, pilocarpine or xanomeline for 1 h followed by washing and either used immediately or after waiting for 23 h. Control groups included cells that were not exposed to agonists and cells that were treated with agonists for 24 h. Radioligand binding and functional assays were conducted to determine the effects of agonist treatments. RESULTS The above treatment protocol with xanomeline resulted in similar effects of the binding of [(3)H]NMS and [(3)H]QNB. When receptor function is blocked using a variety of methods, the long-term effects of xanomeline binding were absent. CONCLUSION Our data indicate that xanomeline wash-resistant binding at the receptor allosteric site leads to receptor downregulation and that receptor activation is necessary for these effects.
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Affiliation(s)
- Meredith J Noetzel
- Division of Neuroscience Research in Psychiatry, University of Minnesota Medical School, Minneapolis, MN 55455, USA
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Gao ZG, Ye K, Göblyös A, Ijzerman AP, Jacobson KA. Flexible modulation of agonist efficacy at the human A3 adenosine receptor by the imidazoquinoline allosteric enhancer LUF6000. BMC Pharmacol 2008; 8:20. [PMID: 19077268 PMCID: PMC2625337 DOI: 10.1186/1471-2210-8-20] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2008] [Accepted: 12/12/2008] [Indexed: 02/08/2023] Open
Abstract
Background A series of 1H-imidazo- [4,5-c]quinolin-4-amine derivatives, represented by LUF6000 (N-(3,4-dichloro-phenyl)-2-cyclohexyl-1H-imidazo [4,5-c]quinolin-4-amine), are allosteric modulators of the human A3 adenosine receptor (AR). Here we studied the modulation by LUF6000 of the maximum effect (Emax) of structurally diverse agonists at the A3 AR stably expressed in CHO cells. Results In an assay of [35S]GTPγS binding, the Emax of the A3 AR agonist Cl-IB-MECA at the A3 AR was lower than that of the non-selective AR agonist NECA. LUF6000 exerted an Emax-enhancing effect at a concentration of 0.1 μM or higher, and was shown to increase the Emax of Cl-IB-MECA and other low-efficacy agonists to a larger extent than that of the high-efficacy agonist NECA. Interestingly, LUF6000 converted a nucleoside A3 AR antagonist MRS542, but not a non-nucleoside antagonist MRS1220, into an agonist. LUF6000 alone did not show any effect. Mathematical modeling was performed to explain the differential effects of LUF6000 on agonists with various Emax. A simple explanation for the observation that LUF6000 has a much stronger effect on Cl-IB-MECA than on NECA derived from the mathematical modeling is that NECA has relatively strong intrinsic efficacy, such that the response is already close to the maximum response. Therefore, LUF6000 cannot enhance Emax much further. Conclusion LUF6000 was found to be an allosteric enhancer of Emax of structurally diverse agonists at the A3 AR, being more effective for low-Emax agonists than for high-Emax agonists. LUF6000 was demonstrated to convert an antagonist into an agonist, which represents the first example in G protein-coupled receptors. The observations from the present study are consistent with that predicted by mathematical modeling.
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Affiliation(s)
- Zhan-Guo Gao
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0810, USA.
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