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Salerno JA, Rehen S. Human pluripotent stem cells as a translational toolkit in psychedelic research in vitro. iScience 2024; 27:109631. [PMID: 38628967 PMCID: PMC11019282 DOI: 10.1016/j.isci.2024.109631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/19/2024] Open
Abstract
Psychedelics, recognized for their impact on perception, are resurging as promising treatments with rapid onset for mood and substance use disorders. Despite increasing evidence from clinical trials, questions persist about the cellular and molecular mechanisms and their precise correlation with treatment outcomes. Murine neurons and immortalized non-neural cell lines harboring overexpressed constructs have shed light on neuroplastic changes mediated by the serotonin 2A receptor (5-HT2AR) as the primary mechanism. However, limitations exist in capturing human- and disease-specific traits. Here, we discuss current accomplishments and prospects for incorporating human pluripotent stem cells (PSCs) to complement these models. PSCs can differentiate into various brain cell types, mirroring endogenous expression patterns and cell identities to recreate disease phenotypes. Brain organoids derived from PSCs resemble cell diversity and patterning, while region-specific organoids simulate circuit-level phenotypes. PSC-based models hold significant promise to illuminate the cellular and molecular substrates of psychedelic-induced phenotypic recovery in neuropsychiatric disorders.
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Affiliation(s)
- José Alexandre Salerno
- D'Or Institute for Research and Education (IDOR), Rio de Janeiro, Brazil
- Graduate Program in Morphological Sciences, Institute of Biomedical Sciences, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
- Department of Morphological Sciences, Biomedical Institute, Federal University of the State of Rio de Janeiro (UNIRIO), Rio de Janeiro, Brazil
| | - Stevens Rehen
- D'Or Institute for Research and Education (IDOR), Rio de Janeiro, Brazil
- Department of Genetics, Institute of Biology, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
- Usona Institute, Fitchburg, WI, USA
- Promega Corporation, Madison, WI, USA
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2
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Saecker L, Häberlein H, Franken S. Investigation of adenosine A1 receptor-mediated β-arrestin 2 recruitment using a split-luciferase assay. Front Pharmacol 2023; 14:1172551. [PMID: 37324481 PMCID: PMC10268005 DOI: 10.3389/fphar.2023.1172551] [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: 02/23/2023] [Accepted: 05/15/2023] [Indexed: 06/17/2023] Open
Abstract
Background: Adenosine A1 receptor (A1AR) plays a prominent role in neurological and cardiac diseases and inflammatory processes. Its endogenous ligand adenosine is known to be one of the key players in the sleep-wake cycle. Like other G protein-coupled receptors (GPCRs), stimulation of A1AR leads to the recruitment of arrestins in addition to the activation of G proteins. So far, little is known about the role of these proteins in signal transduction and regulation of A1AR compared to the activation of G proteins. In this work, we characterized a live cell assay for A1AR-mediated β-arrestin 2 recruitment. We have applied this assay to a set of different compounds that interact with this receptor. Methods: Based on NanoBit® technology, a protein complementation assay was developed in which the A1AR is coupled to the large part of the nanoluciferase (LgBiT), whereas its small part (SmBiT) is fused to the N-terminus of β-arrestin 2. Stimulation of A1AR results in the recruitment of β-arrestin 2 and subsequent complementation of a functional nanoluciferase. For comparison, corresponding data on the effect of receptor stimulation on intracellular cAMP levels were collected for some data sets using the GloSensor™ assay. Results: The assay gives highly reproducible results with a very good signal-to-noise ratio. Capadenoson, in contrast to adenosine, CPA, or NECA, shows only partial agonism in this assay with respect to the recruitment of β-arrestin 2, whereas it shows full agonism in the case of the inhibitory effect of A1AR on cAMP production. By using a GRK2 inhibitor, it becomes clear that the recruitment is at least partially dependent on the phosphorylation of the receptor by this kinase. Interestingly, this was also the first time that we demonstrate the A1AR-mediated recruitment of β-arrestin 2 by stimulation with a valerian extract. Conclusion: The presented assay is a useful tool for the quantitative study of A1AR-mediated β-arrestin 2 recruitment. It allows data collection for stimulatory, inhibitory, and modulatory substances and is also suitable for more complex substance mixtures such as valerian extract.
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Wang J, Bhattarai A, Do HN, Akhter S, Miao Y. Molecular Simulations and Drug Discovery of Adenosine Receptors. Molecules 2022; 27:2054. [PMID: 35408454 PMCID: PMC9000248 DOI: 10.3390/molecules27072054] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 03/18/2022] [Accepted: 03/20/2022] [Indexed: 02/02/2023] Open
Abstract
G protein-coupled receptors (GPCRs) represent the largest family of human membrane proteins. Four subtypes of adenosine receptors (ARs), the A1AR, A2AAR, A2BAR and A3AR, each with a unique pharmacological profile and distribution within the tissues in the human body, mediate many physiological functions and serve as critical drug targets for treating numerous human diseases including cancer, neuropathic pain, cardiac ischemia, stroke and diabetes. The A1AR and A3AR preferentially couple to the Gi/o proteins, while the A2AAR and A2BAR prefer coupling to the Gs proteins. Adenosine receptors were the first subclass of GPCRs that had experimental structures determined in complex with distinct G proteins. Here, we will review recent studies in molecular simulations and computer-aided drug discovery of the adenosine receptors and also highlight their future research opportunities.
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Affiliation(s)
| | | | | | | | - Yinglong Miao
- Center for Computational Biology and Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66047, USA; (J.W.); (A.B.); (H.N.D.); (S.A.)
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4
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Wu LX, Dong YP, Zhu QM, Zhang B, Ai BL, Yan T, Zhang GH, Sun L. Effects of dezocine on morphine tolerance and opioid receptor expression in a rat model of bone cancer pain. BMC Cancer 2021; 21:1128. [PMID: 34670518 PMCID: PMC8529774 DOI: 10.1186/s12885-021-08850-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 10/05/2021] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Clinically, the coadministration of opioids to enhance antinociception and decrease tolerance has attracted increasing research attention. We investigated the effects of dezocine, a mu- and kappa-opioid receptor agonist/antagonist, on morphine tolerance and explored the involvement of opioid receptor expression in a rat model of bone cancer pain. METHODS Thermal nociceptive thresholds were measured after the subcutaneous injection of morphine (10 mg/kg) alone or combined with dezocine (10 or 1 mg/kg) for 7 consecutive days. Real-time PCR and western blot analysis were used to examine opioid receptor expression in the periaqueductal gray (PAG) and spinal cord. RESULTS The analgesic effect was significantly decreased after 4 days of morphine administration. We observed that low-dose dezocine significantly attenuated morphine tolerance without reducing the analgesic effect of morphine. Low-dose dezocine coadministration significantly reversed the downregulated expression of mu (MOR) and delta (DOR) opioid receptors in the PAG and the upregulated expression of kappa (KOR) and DOR in the spinal cord induced by morphine. Moreover, low-dose dezocine coadministered with morphine significantly inhibited KOR expression in both the PAG and spinal cord. CONCLUSIONS The combination of low-dose dezocine with morphine may prevent or delay the development of morphine tolerance in a rat model of bone cancer pain. The regulation of opioid receptor expression in the PAG and spinal cord may be part of the mechanism.
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MESH Headings
- Animals
- Female
- Rats
- Analgesics, Opioid/administration & dosage
- Analgesics, Opioid/pharmacology
- Bone Neoplasms/complications
- Bridged Bicyclo Compounds, Heterocyclic/administration & dosage
- Bridged Bicyclo Compounds, Heterocyclic/pharmacology
- Cancer Pain/drug therapy
- Cancer Pain/metabolism
- Cell Line, Tumor
- Down-Regulation/drug effects
- Drug Interactions
- Drug Therapy, Combination/methods
- Drug Tolerance
- Hot Temperature
- Hyperalgesia/physiopathology
- Morphine/administration & dosage
- Morphine/pharmacology
- Pain Measurement/drug effects
- Pain Threshold
- Periaqueductal Gray/metabolism
- Rats, Wistar
- Receptors, Opioid/drug effects
- Receptors, Opioid/metabolism
- Spinal Cord/metabolism
- Tetrahydronaphthalenes/administration & dosage
- Tetrahydronaphthalenes/pharmacology
- Up-Regulation/drug effects
- Disease Models, Animal
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Affiliation(s)
- Lin-Xin Wu
- Department of Anesthesiology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China
| | - Yan-Peng Dong
- Department of Anesthesiology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China
| | - Qian-Mei Zhu
- Department of Anesthesiology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China
| | - Bo Zhang
- Department of Anesthesiology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China
| | - Bo-Lun Ai
- Department of Breast Surgical Oncology, National Cancer Center/National Clinical Research Center Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China
| | - Tao Yan
- Department of Anesthesiology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China.
| | - Guo-Hua Zhang
- Department of Anesthesiology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China.
| | - Li Sun
- Department of Anesthesiology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China.
- Department of Anesthesiology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital & Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen, 518100, China.
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Wang J, Arantes PR, Bhattarai A, Hsu RV, Pawnikar S, Huang YMM, Palermo G, Miao Y. Gaussian accelerated molecular dynamics (GaMD): principles and applications. WILEY INTERDISCIPLINARY REVIEWS. COMPUTATIONAL MOLECULAR SCIENCE 2021; 11:e1521. [PMID: 34899998 PMCID: PMC8658739 DOI: 10.1002/wcms.1521] [Citation(s) in RCA: 95] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 01/28/2021] [Indexed: 12/20/2022]
Abstract
Gaussian accelerated molecular dynamics (GaMD) is a robust computational method for simultaneous unconstrained enhanced sampling and free energy calculations of biomolecules. It works by adding a harmonic boost potential to smooth biomolecular potential energy surface and reduce energy barriers. GaMD greatly accelerates biomolecular simulations by orders of magnitude. Without the need to set predefined reaction coordinates or collective variables, GaMD provides unconstrained enhanced sampling and is advantageous for simulating complex biological processes. The GaMD boost potential exhibits a Gaussian distribution, thereby allowing for energetic reweighting via cumulant expansion to the second order (i.e., "Gaussian approximation"). This leads to accurate reconstruction of free energy landscapes of biomolecules. Hybrid schemes with other enhanced sampling methods, such as the replica exchange GaMD (rex-GaMD) and replica exchange umbrella sampling GaMD (GaREUS), have also been introduced, further improving sampling and free energy calculations. Recently, new "selective GaMD" algorithms including the ligand GaMD (LiGaMD) and peptide GaMD (Pep-GaMD) enabled microsecond simulations to capture repetitive dissociation and binding of small-molecule ligands and highly flexible peptides. The simulations then allowed highly efficient quantitative characterization of the ligand/peptide binding thermodynamics and kinetics. Taken together, GaMD and its innovative variants are applicable to simulate a wide variety of biomolecular dynamics, including protein folding, conformational changes and allostery, ligand binding, peptide binding, protein-protein/nucleic acid/carbohydrate interactions, and carbohydrate/nucleic acid interactions. In this review, we present principles of the GaMD algorithms and recent applications in biomolecular simulations and drug design.
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Affiliation(s)
- Jinan Wang
- Center for Computational Biology and Department of Molecular Biosciences, University of Kansas, 2030 Becker Dr., Lawrence, KS, 66047, United States
| | - Pablo R Arantes
- Department of Bioengineering, University of California Riverside, 900 University Avenue, Riverside, CA 92512, United States
| | - Apurba Bhattarai
- Center for Computational Biology and Department of Molecular Biosciences, University of Kansas, 2030 Becker Dr, Lawrence, KS, 66047, United States
| | - Rohaine V Hsu
- Department of Bioengineering, University of California Riverside, 900 University Avenue, Riverside, CA 92512, United States
| | - Shristi Pawnikar
- Center for Computational Biology and Department of Molecular Biosciences, University of Kansas, 2030 Becker Dr., Lawrence, KS, 66047, United States
| | - Yu-Ming M Huang
- Department of Physics & Astronomy, Wayne State University, 666 W Hancock St, Detroit, MI 48207, USA
| | - Giulia Palermo
- Department of Bioengineering and Department of Chemistry, University of California Riverside, 900 University Avenue, Riverside, CA 92512, United States
| | - Yinglong Miao
- Center for Computational Biology and Department of Molecular Biosciences, University of Kansas, 2030 Becker Dr., Lawrence, Kansas 66047, United States
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Horváth VB, Soltész-Katona E, Wisniewski É, Rajki A, Halász E, Enyedi B, Hunyady L, Tóth AD, Szanda G. Optimization of the Heterologous Expression of the Cannabinoid Type-1 (CB 1) Receptor. Front Endocrinol (Lausanne) 2021; 12:740913. [PMID: 34745007 PMCID: PMC8564136 DOI: 10.3389/fendo.2021.740913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 09/21/2021] [Indexed: 11/13/2022] Open
Abstract
The G protein-coupled type 1 cannabinoid receptor (CB1R) mediates virtually all classic cannabinoid effects, and both its agonists and antagonists hold major therapeutic potential. Heterologous expression of receptors is vital for pharmacological research, however, overexpression of these proteins may fundamentally alter their localization pattern, change the signalling partner preference and may also spark artificial clustering. Additionally, recombinant CB1Rs are prone to intense proteasomal degradation, which may necessitate substantial modifications, such as N-terminal truncation or signal sequence insertion, for acceptable cell surface expression. We report here that tuning down the expression intensity of the full-length CB1R reduces proteasomal degradation and offers receptor levels that are comparable to those of endogenous CB1 receptors. As opposed to high-efficiency expression with conventional promoters, weak promoter-driven CB1R expression provides ERK 1/2 and p38 MAPK signalling that closely resemble the activity of endogenous CB1Rs. Moreover, weakly expressed CB1R variants exhibit plasma membrane localization, preserve canonical Gi-signalling but prevent CB1R-Gs coupling observed with high-expression variants. Based on these findings, we propose that lowering the expression level of G protein-coupled receptors should always be considered in heterologous expression systems in order to reduce the pressure on the proteasomal machinery and to avoid potential signalling artefacts.
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Affiliation(s)
| | - Eszter Soltész-Katona
- Department of Physiology, Semmelweis University, Budapest, Hungary
- MTA-SE Laboratory of Molecular Physiology, Eötvös Loránd Research Network, Budapest, Hungary
| | - Éva Wisniewski
- Department of Physiology, Semmelweis University, Budapest, Hungary
| | - Anikó Rajki
- Department of Physiology, Semmelweis University, Budapest, Hungary
- MTA-SE Laboratory of Molecular Physiology, Eötvös Loránd Research Network, Budapest, Hungary
| | - Eszter Halász
- Department of Physiology, Semmelweis University, Budapest, Hungary
- MTA-SE Laboratory of Molecular Physiology, Eötvös Loránd Research Network, Budapest, Hungary
| | - Balázs Enyedi
- Department of Physiology, Semmelweis University, Budapest, Hungary
- MTA-SE Lendület Tissue Damage Research Group, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary
- HCEMM-SE Inflammatory Signaling Research Group, Department of Physiology, Semmelweis University, Budapest, Hungary
| | - László Hunyady
- Department of Physiology, Semmelweis University, Budapest, Hungary
- MTA-SE Laboratory of Molecular Physiology, Eötvös Loránd Research Network, Budapest, Hungary
| | - András Dávid Tóth
- MTA-SE Laboratory of Molecular Physiology, Eötvös Loránd Research Network, Budapest, Hungary
- Department of Internal Medicine and Haematology, Semmelweis University, Budapest, Hungary
| | - Gergő Szanda
- Department of Physiology, Semmelweis University, Budapest, Hungary
- MTA-SE Laboratory of Molecular Physiology, Eötvös Loránd Research Network, Budapest, Hungary
- *Correspondence: Gergő Szanda,
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Santiago AR, Madeira MH, Boia R, Aires ID, Rodrigues-Neves AC, Santos PF, Ambrósio AF. Keep an eye on adenosine: Its role in retinal inflammation. Pharmacol Ther 2020; 210:107513. [PMID: 32109489 DOI: 10.1016/j.pharmthera.2020.107513] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Adenosine is an endogenous purine nucleoside ubiquitously distributed throughout the body that interacts with G protein-coupled receptors, classified in four subtypes: A1R, A2AR, A2BR and A3R. Among the plethora of functions of adenosine, it has been increasingly recognized as a key mediator of the immune response. Neuroinflammation is a feature of chronic neurodegenerative diseases and contributes to the pathophysiology of several retinal degenerative diseases. Animal models of retinal diseases are helping to elucidate the regulatory roles of adenosine receptors in the development and progression of those diseases. Mounting evidence demonstrates that the adenosinergic system is altered in the retina during pathological conditions, compromising retinal physiology. This review focuses on the roles played by adenosine and the elements of the adenosinergic system (receptors, enzymes, transporters) in the neuroinflammatory processes occurring in the retina. An improved understanding of the molecular and cellular mechanisms of the signalling pathways mediated by adenosine underlying the onset and progression of retinal diseases will pave the way towards the identification of new therapeutic approaches.
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Affiliation(s)
- Ana Raquel Santiago
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal; Association for Innovation and Biomedical Research on Light and Image (AIBILI), Coimbra, 3000-548 Coimbra, Portugal.
| | - Maria H Madeira
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal; Association for Innovation and Biomedical Research on Light and Image (AIBILI), Coimbra, 3000-548 Coimbra, Portugal
| | - Raquel Boia
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal
| | - Inês Dinis Aires
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal
| | - Ana Catarina Rodrigues-Neves
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal
| | - Paulo Fernando Santos
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal; Department of Life Sciences, University of Coimbra, 3000-456 Coimbra, Portugal
| | - António Francisco Ambrósio
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal; Association for Innovation and Biomedical Research on Light and Image (AIBILI), Coimbra, 3000-548 Coimbra, Portugal.
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8
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Crespo M, León‐Navarro DA, Ruíz MÁ, Martín M. Hyperthermia‐induced seizures produce long‐term effects on the functionality of adenosine A
1
receptor in rat cerebral cortex. Int J Dev Neurosci 2020; 80:1-12. [DOI: 10.1002/jdn.10000] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 12/09/2019] [Indexed: 12/12/2022] Open
Affiliation(s)
- María Crespo
- Departamento de Química Inorgánica Orgánica y Bioquímica Facultad de Ciencias y Tecnologías Químicas Centro Regional de Investigaciones Biomédicas Universidad de Castilla‐La Mancha Ciudad Real Spain
| | - David Agustín León‐Navarro
- Departamento de Química Inorgánica Orgánica y Bioquímica Facultad de Ciencias y Tecnologías Químicas Centro Regional de Investigaciones Biomédicas Universidad de Castilla‐La Mancha Ciudad Real Spain
| | - María Ángeles Ruíz
- Departamento de Química Inorgánica Orgánica y Bioquímica Facultad de Ciencias y Tecnologías Químicas Centro Regional de Investigaciones Biomédicas Universidad de Castilla‐La Mancha Ciudad Real Spain
| | - Mairena Martín
- Departamento de Química Inorgánica Orgánica y Bioquímica Facultad de Ciencias y Tecnologías Químicas Facultad de Medicina de Ciudad Real Centro Regional de Investigaciones Biomédicas Universidad de Castilla‐La Mancha Ciudad Real Spain
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9
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Wang J, Miao Y. Mechanistic Insights into Specific G Protein Interactions with Adenosine Receptors. J Phys Chem B 2019; 123:6462-6473. [PMID: 31283874 DOI: 10.1021/acs.jpcb.9b04867] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Coupling between G-protein-coupled receptors (GPCRs) and the G proteins is a key step in cellular signaling. Despite extensive experimental and computational studies, the mechanism of specific GPCR-G protein coupling remains poorly understood. This has greatly hindered effective drug design of GPCRs that are primary targets of ∼1/3 of currently marketed drugs. Here, we have employed all-atom simulations using a robust Gaussian accelerated molecular dynamics (GaMD) method to decipher the mechanism of the GPCR-G protein interactions. Adenosine receptors (ARs) were used as model systems based on very recently determined cryo-EM structures of the A1AR and A2AAR coupled with the Gi and Gs proteins, respectively. Changing the Gi protein to the Gs led to increased fluctuations in the A1AR and agonist adenosine (ADO), while agonist 5'-N-ethylcarboxamidoadenosine (NECA) binding in the A2AAR could be still stabilized upon changing the Gs protein to the Gi. Free energy calculations identified one stable low-energy conformation for each of the A1AR-Gi and A2AAR-Gs complexes as in the cryo-EM structures, similarly for the A2AAR-Gi complex. In contrast, the ADO agonist and Gs protein sampled multiple conformations in the A1AR-Gs system. GaMD simulations thus indicated that the A1AR preferred to couple with the Gi protein to the Gs, while the A2AAR could couple with both the Gs and Gi proteins, being highly consistent with experimental findings of the ARs. More importantly, detailed analysis of the atomic simulations showed that the specific AR-G protein coupling resulted from remarkably complementary residue interactions at the protein interface, involving mainly the receptor transmembrane 6 helix and the Gα α5 helix and α4-β6 loop. In summary, the GaMD simulations have provided unprecedented insights into the dynamic mechanism of specific GPCR-G protein interactions at an atomistic level.
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Affiliation(s)
- Jinan Wang
- Center for Computational Biology and Department of Molecular Biosciences , University of Kansas , Lawrence , Kansas 66047 , United States
| | - Yinglong Miao
- Center for Computational Biology and Department of Molecular Biosciences , University of Kansas , Lawrence , Kansas 66047 , United States
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10
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Seyedabadi M, Ghahremani MH, Albert PR. Biased signaling of G protein coupled receptors (GPCRs): Molecular determinants of GPCR/transducer selectivity and therapeutic potential. Pharmacol Ther 2019; 200:148-178. [PMID: 31075355 DOI: 10.1016/j.pharmthera.2019.05.006] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 04/26/2019] [Indexed: 02/07/2023]
Abstract
G protein coupled receptors (GPCRs) convey signals across membranes via interaction with G proteins. Originally, an individual GPCR was thought to signal through one G protein family, comprising cognate G proteins that mediate canonical receptor signaling. However, several deviations from canonical signaling pathways for GPCRs have been described. It is now clear that GPCRs can engage with multiple G proteins and the line between cognate and non-cognate signaling is increasingly blurred. Furthermore, GPCRs couple to non-G protein transducers, including β-arrestins or other scaffold proteins, to initiate additional signaling cascades. Receptor/transducer selectivity is dictated by agonist-induced receptor conformations as well as by collateral factors. In particular, ligands stabilize distinct receptor conformations to preferentially activate certain pathways, designated 'biased signaling'. In this regard, receptor sequence alignment and mutagenesis have helped to identify key receptor domains for receptor/transducer specificity. Furthermore, molecular structures of GPCRs bound to different ligands or transducers have provided detailed insights into mechanisms of coupling selectivity. However, receptor dimerization, compartmentalization, and trafficking, receptor-transducer-effector stoichiometry, and ligand residence and exposure times can each affect GPCR coupling. Extrinsic factors including cell type or assay conditions can also influence receptor signaling. Understanding these factors may lead to the development of improved biased ligands with the potential to enhance therapeutic benefit, while minimizing adverse effects. In this review, evidence for ligand-specific GPCR signaling toward different transducers or pathways is elaborated. Furthermore, molecular determinants of biased signaling toward these pathways and relevant examples of the potential clinical benefits and pitfalls of biased ligands are discussed.
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Affiliation(s)
- Mohammad Seyedabadi
- Department of Pharmacology, School of Medicine, Bushehr University of Medical Sciences, Iran; Education Development Center, Bushehr University of Medical Sciences, Iran
| | | | - Paul R Albert
- Ottawa Hospital Research Institute, Neuroscience, University of Ottawa, Canada.
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Luttrell LM, Wang J, Plouffe B, Smith JS, Yamani L, Kaur S, Jean-Charles PY, Gauthier C, Lee MH, Pani B, Kim J, Ahn S, Rajagopal S, Reiter E, Bouvier M, Shenoy SK, Laporte SA, Rockman HA, Lefkowitz RJ. Manifold roles of β-arrestins in GPCR signaling elucidated with siRNA and CRISPR/Cas9. Sci Signal 2018; 11:11/549/eaat7650. [PMID: 30254056 DOI: 10.1126/scisignal.aat7650] [Citation(s) in RCA: 132] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
G protein-coupled receptors (GPCRs) use diverse mechanisms to regulate the mitogen-activated protein kinases ERK1/2. β-Arrestins (βArr1/2) are ubiquitous inhibitors of G protein signaling, promoting GPCR desensitization and internalization and serving as scaffolds for ERK1/2 activation. Studies using CRISPR/Cas9 to delete βArr1/2 and G proteins have cast doubt on the role of β-arrestins in activating specific pools of ERK1/2. We compared the effects of siRNA-mediated knockdown of βArr1/2 and reconstitution with βArr1/2 in three different parental and CRISPR-derived βArr1/2 knockout HEK293 cell pairs to assess the effect of βArr1/2 deletion on ERK1/2 activation by four Gs-coupled GPCRs. In all parental lines with all receptors, ERK1/2 stimulation was reduced by siRNAs specific for βArr2 or βArr1/2. In contrast, variable effects were observed with CRISPR-derived cell lines both between different lines and with activation of different receptors. For β2 adrenergic receptors (β2ARs) and β1ARs, βArr1/2 deletion increased, decreased, or had no effect on isoproterenol-stimulated ERK1/2 activation in different CRISPR clones. ERK1/2 activation by the vasopressin V2 and follicle-stimulating hormone receptors was reduced in these cells but was enhanced by reconstitution with βArr1/2. Loss of desensitization and receptor internalization in CRISPR βArr1/2 knockout cells caused β2AR-mediated stimulation of ERK1/2 to become more dependent on G proteins, which was reversed by reintroducing βArr1/2. These data suggest that βArr1/2 function as a regulatory hub, determining the balance between mechanistically different pathways that result in activation of ERK1/2, and caution against extrapolating results obtained from βArr1/2- or G protein-deleted cells to GPCR behavior in native systems.
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Affiliation(s)
- Louis M Luttrell
- Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, USA.,Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425, USA.,Research Service of the Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC 29401, USA
| | - Jialu Wang
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
| | - Bianca Plouffe
- Department of Biochemistry and Molecular Medicine, Institute for Research in Immunology and Cancer, University of Montreal, Montreal, Quebec H3C IJ4, Canada
| | - Jeffrey S Smith
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA.,Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
| | - Lama Yamani
- Department of Medicine, Research Institute of the McGill University Health Center, McGill University, Montreal, Quebec H4A 3J1, Canada
| | - Suneet Kaur
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
| | | | - Christophe Gauthier
- Physiologie de la Reproduction et des Comportements, Institut National de la Recherche Agronomique, CNRS, Université de Tours, 37380 Nouzilly, France
| | - Mi-Hye Lee
- Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Biswaranjan Pani
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
| | - Jihee Kim
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
| | - Seungkirl Ahn
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
| | - Sudarshan Rajagopal
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA.,Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
| | - Eric Reiter
- Physiologie de la Reproduction et des Comportements, Institut National de la Recherche Agronomique, CNRS, Université de Tours, 37380 Nouzilly, France
| | - Michel Bouvier
- Department of Biochemistry and Molecular Medicine, Institute for Research in Immunology and Cancer, University of Montreal, Montreal, Quebec H3C IJ4, Canada
| | - Sudha K Shenoy
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA.,Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Stéphane A Laporte
- Department of Medicine, Research Institute of the McGill University Health Center, McGill University, Montreal, Quebec H4A 3J1, Canada
| | - Howard A Rockman
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA.,Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA.,Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Robert J Lefkowitz
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA. .,Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA.,Howard Hughes Medical Institute, Duke University Medical Center, Durham, NC 27710, USA
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Finlay DB, Cawston EE, Grimsey NL, Hunter MR, Korde A, Vemuri VK, Makriyannis A, Glass M. Gα s signalling of the CB 1 receptor and the influence of receptor number. Br J Pharmacol 2017; 174:2545-2562. [PMID: 28516479 PMCID: PMC5513864 DOI: 10.1111/bph.13866] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 04/30/2017] [Accepted: 05/09/2017] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND AND PURPOSE CB1 receptor signalling is canonically mediated through inhibitory Gαi proteins, but occurs through other G proteins under some circumstances, Gαs being the most characterized secondary pathway. Determinants of this signalling switch identified to date include Gαi blockade, CB1 /D2 receptor co-stimulation, CB1 agonist class and cell background. Hence, we examined the effects of receptor number and different ligands on CB1 receptor signalling. EXPERIMENTAL APPROACH CB1 receptors were expressed in HEK cells at different levels, and signalling characterized for cAMP by real-time BRET biosensor -CAMYEL - and for phospho-ERK by AlphaScreen. Homogenate and whole cell radioligand binding assays were performed to characterize AM6544, a novel irreversible CB1 receptor antagonist. KEY RESULTS In HEK cells expressing high levels of CB1 receptors, agonist treatment stimulated cAMP, a response not known to be mediated by receptor number. Δ9 -THC and BAY59-3074 increased cAMP only in high-expressing cells pretreated with pertussis toxin, and agonists demonstrated more diverse signalling profiles in the stimulatory pathway than the canonical inhibitory pathway. Pharmacological CB1 receptor knockdown and Gαi 1 supplementation restored canonical Gαi signalling to high-expressing cells. Constitutive signalling in both low- and high-expressing cells was Gαi -mediated. CONCLUSION AND IMPLICATIONS CB1 receptor coupling to opposing G proteins is determined by both receptor and G protein expression levels, which underpins a mechanism for non-canonical signalling in a fashion consistent with Gαs signalling. CB1 receptors mediate opposite consequences in endpoints such as tumour viability depending on expression levels; our results may help to explain such effects at the level of G protein coupling.
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Affiliation(s)
- David B Finlay
- Department of Pharmacology and Clinical Pharmacology, Faculty of Medical and Health SciencesUniversity of AucklandAucklandNew Zealand
| | - Erin E Cawston
- Department of Pharmacology and Clinical Pharmacology, Faculty of Medical and Health SciencesUniversity of AucklandAucklandNew Zealand
| | - Natasha L Grimsey
- Department of Pharmacology and Clinical Pharmacology, Faculty of Medical and Health SciencesUniversity of AucklandAucklandNew Zealand
| | - Morag R Hunter
- Department of Pharmacology and Clinical Pharmacology, Faculty of Medical and Health SciencesUniversity of AucklandAucklandNew Zealand
| | - Anisha Korde
- Center for Drug DiscoveryNortheastern UniversityBostonMAUSA
| | - V Kiran Vemuri
- Center for Drug DiscoveryNortheastern UniversityBostonMAUSA
| | | | - Michelle Glass
- Department of Pharmacology and Clinical Pharmacology, Faculty of Medical and Health SciencesUniversity of AucklandAucklandNew Zealand
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Kent TC, Thompson KSJ, Naylor LH. Development of a Generic Dual-Reporter Gene Assay for Screening G-Protein-Coupled Receptors. ACTA ACUST UNITED AC 2016; 10:437-46. [PMID: 16093553 DOI: 10.1177/1087057105275033] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Multiple assay formats have been developed for the pharmacological characterization of G-protein-coupled receptors (GPCRs) and for screening orphan receptors. However, the increased pace of target identification and the rapid expansion of compound libraries present the need to develop novel assay formats capable of screeningmultipleGPCRs simultaneously. To address this need, the authors have developed a generic dual-reporter gene assay that can detect ligand activity at 2 GPCRs within the same assay. Two stableHEK293 cell lineswere generated expressing either a firefly ( Photinus) luciferase gene under the control ofmultiple cAMP-response elements (CREs) or a Renillaluciferase gene under the control ofmultiple 12-Otetradecanoylphorbol-13-acetate (TPA)-responsive elements (TREs). Coseeded reporter cells were used to assess ligandbinding activity at bothGβ s-and Gβ q-coupled receptors. By selectively coexpressing receptors with a chimeric G-protein, agonist activitywas assessed atGβ i/o-coupled receptors in combinationwith eitherGβ s-or Gβ q-coupled receptors. The dual-reporter gene assaywas shown to be capable of simultaneously performing duplexed screens for a variety of agonist and/or antagonist combinations. The data generated from the duplexed reporter assays were pharmacologically relevant, and Zβ factor analysis indicated the suitability of both agonist and antagonist screens for use in high-throughput screening.
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Affiliation(s)
- Toby C Kent
- Research School of Biosciences, University of Kent, Canterbury, Kent, UK
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Ranganathan A, Stoddart LA, Hill SJ, Carlsson J. Fragment-Based Discovery of Subtype-Selective Adenosine Receptor Ligands from Homology Models. J Med Chem 2015; 58:9578-90. [PMID: 26592528 DOI: 10.1021/acs.jmedchem.5b01120] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Fragment-based lead discovery (FBLD) holds great promise for drug discovery, but applications to G protein-coupled receptors (GPCRs) have been limited by a lack of sensitive screening techniques and scarce structural information. If virtual screening against homology models of GPCRs could be used to identify fragment ligands, FBLD could be extended to numerous important drug targets and contribute to efficient lead generation. Access to models of multiple receptors may further enable the discovery of fragments that bind specifically to the desired target. To investigate these questions, we used molecular docking to screen >500 000 fragments against homology models of the A3 and A1 adenosine receptors (ARs) with the goal to discover A3AR-selective ligands. Twenty-one fragments with predicted A3AR-specific binding were evaluated in live-cell fluorescence-based assays; of eight verified ligands, six displayed A3/A1 selectivity, and three of these had high affinities ranging from 0.1 to 1.3 μM. Subsequently, structure-guided fragment-to-lead optimization led to the identification of a >100-fold-selective antagonist with nanomolar affinity from commercial libraries. These results highlight that molecular docking screening can guide fragment-based discovery of selective ligands even if the structures of both the target and antitarget receptors are unknown. The same approach can be readily extended to a large number of pharmaceutically important targets.
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Affiliation(s)
- Anirudh Ranganathan
- Science for Life Laboratory, Department of Biochemistry and Biophysics, and Center for Biomembrane Research, Stockholm University , SE-106 91 Stockholm, Sweden
| | - Leigh A Stoddart
- Cell Signalling Research Group, School of Life Sciences, University of Nottingham , Nottingham NG7 2UH, U.K
| | - Stephen J Hill
- Cell Signalling Research Group, School of Life Sciences, University of Nottingham , Nottingham NG7 2UH, U.K
| | - Jens Carlsson
- Science for Life Laboratory, Department of Medicinal Chemistry, BMC, Uppsala University , P.O. Box 574, SE-751 23 Uppsala, Sweden
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Puhl SL, Kazakov A, Müller A, Fries P, Wagner DR, Böhm M, Maack C, Devaux Y. Adenosine A1 receptor activation attenuates cardiac hypertrophy and fibrosis in response to α1 -adrenoceptor stimulation in vivo. Br J Pharmacol 2015; 173:88-102. [PMID: 26406609 DOI: 10.1111/bph.13339] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 08/25/2015] [Accepted: 08/27/2015] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND AND PURPOSE Adenosine has been proposed to exert anti-hypertrophic effects. However, the precise regulation and the role of the different adenosine receptor subtypes in the heart and their effects on hypertrophic signalling are largely unknown. We aimed to characterize expression and function of adenosine A1 receptors following hypertrophic stimulation in vitro and in vivo. EXPERIMENTAL APPROACH Pro-hypertrophic stimuli and adenosine A1 receptor stimulation of neonatal rat cardiomyocytes and male C57/Bl6 mice, sc. drug administration, real-time PCR, (3) [H]-leucine-incorporation assay, immunostaining, tissue staining, Western blots, gravimetric analyses and echocardiography were applied in this study. KEY RESULTS In neonatal rat cardiomyocyte cultures, phenylephrine, but not angiotensin II or insulin-like growth factor 1 (IGF1), up-regulated adenosine A1 receptors concentration-dependently. The hypertrophic phenotype (cardiomyocyte size, sarcomeric organization, total protein synthesis, c-fos expression) mediated by phenylephrine (10 μM), but not that by angiotensinII (1 μM) or IGF1 (20 ng·mL(-1) ), was counteracted by the selective A1 receptor agonist, N6-cyclopentyladenosine. In C57/BL6 mice, continuous N6-cyclopentyladenosine infusion (2 mg·kg(-1) ·day(-1) ; 21 days) blunted phenylephrine (120 mg·kg(-1) ·day(-1) ; 21 days) induced hypertrophy (heart weight, cardiomyocyte size and fetal genes), fibrosis, MMP 2 up-regulation and generation of oxidative stress - all hallmarks of maladaptive remodelling. Concurrently, phenylephrine administration increased expression of adenosine A1 receptors. CONCLUSIONS AND IMPLICATIONS We have presented evidence for a negative feedback mechanism attenuating pathological myocardial hypertrophy following α1 -adrenoceptor stimulation. Our results suggest adenosine A1 receptors as potential targets for therapeutic strategies to prevent transition from compensated myocardial hypertrophy to decompensated heart failure due to chronic cardiac pressure overload.
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Affiliation(s)
- S-L Puhl
- Klinik für Innere Medizin III (Kardiologie, Angiologie, Internistische Intensivmedizin), Universitätsklinikum des Saarlandes, Homburg/Saar, Germany
| | - A Kazakov
- Klinik für Innere Medizin III (Kardiologie, Angiologie, Internistische Intensivmedizin), Universitätsklinikum des Saarlandes, Homburg/Saar, Germany
| | - A Müller
- Klinik for interventionelle Radiologie, Universitätsklinikum des Saarlandes, Homburg/Saar, Germany
| | - P Fries
- Klinik for interventionelle Radiologie, Universitätsklinikum des Saarlandes, Homburg/Saar, Germany
| | - D R Wagner
- Luxembourg Institute of Health, Strassen, Luxembourg
| | - M Böhm
- Klinik für Innere Medizin III (Kardiologie, Angiologie, Internistische Intensivmedizin), Universitätsklinikum des Saarlandes, Homburg/Saar, Germany
| | - C Maack
- Klinik für Innere Medizin III (Kardiologie, Angiologie, Internistische Intensivmedizin), Universitätsklinikum des Saarlandes, Homburg/Saar, Germany
| | - Y Devaux
- Luxembourg Institute of Health, Strassen, Luxembourg
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Odagaki Y, Kinoshita M, Ota T, Javier Meana J, Callado LF, García-Sevilla JA. Adenosine A1( )receptors are selectively coupled to Gα(i-3) in postmortem human brain cortex: Guanosine-5'-O-(3-[(35)S]thio)triphosphate ([(35)S]GTPγS) binding/immunoprecipitation study. Eur J Pharmacol 2015. [PMID: 26213104 DOI: 10.1016/j.ejphar.2015.07.049] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
By means of guanosine-5'-O-(3-[(35)S]thio)triphosphate ([(35)S]GTPγS) binding assay combined with immunoprecipitation using anti-Gα subunit antibody, we recently reported 5-HT2A receptor- and M1 muscarinic acetylcholine receptor-mediated Gαq activation in rat cerebral cortical membranes (Odagaki et al., 2014). In the present study, this method has been applied to postmortem human brains, with focusing on adenosine receptor-mediated G-protein activation. In the exploratory experiments using a series of agonists and the antibodies specific to each Gα subtypes in the presence of low (10 nM) or high (50 μM) concentration of GDP, the most prominent increases in specific [(35)S]GTPγS binding in the membranes prepared from human prefrontal cortex were obtained for the combinations of adenosine (1mM)/anti-Gαi-3 in the presence of 50 μM GDP as well as 5-HT (100 μM)/anti-Gαq and carbachol (1mM)/anti-Gαq in the presence of 10nM GDP. Adenosine-induced activation of Gαi-3 emerged only when GDP concentrations were increased higher than 10 μM, and the following experiments were performed in the presence of 300 μM GDP. Adenosine increased specific [(35)S]GTPγS binding to Gαi-3 in a concentration-dependent manner to 251.4% of the basal unstimulated binding, with an EC50 of 1.77 μM. The involvement of adenosine A1 receptor was verified by the experiments using selective agonists and antagonists at adenosine A1 or A3 receptor. Among the α subunits of Gi/o class (Gαi-1, Gαi-2, Gαi-3, and Gαo.), only Gαi-3 was activated by 1mM adenosine, indicating that human brain adenosine A1 receptor is coupled preferentially, if not exclusively, to Gαi-3.
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Affiliation(s)
- Yuji Odagaki
- Department of Psychiatry, Faculty of Medicine, Saitama Medical University, 38 Morohongo, Iruma-gun, Moroyama-machi, Saitama 350-0495, Japan.
| | - Masakazu Kinoshita
- Department of Psychiatry, Faculty of Medicine, Saitama Medical University, 38 Morohongo, Iruma-gun, Moroyama-machi, Saitama 350-0495, Japan
| | - Toshio Ota
- Department of Psychiatry, Faculty of Medicine, Saitama Medical University, 38 Morohongo, Iruma-gun, Moroyama-machi, Saitama 350-0495, Japan
| | - J Javier Meana
- Department of Pharmacology, University of the Basque Country, UPV/EHU, E-48940 Leioa, Bizkaia, and Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, Spain
| | - Luis F Callado
- Department of Pharmacology, University of the Basque Country, UPV/EHU, E-48940 Leioa, Bizkaia, and Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, Spain
| | - Jesús A García-Sevilla
- Laboratory of Neuropharmacology, IUNICS/IdISPa, University of the Balearic Islands (UIB), and Redes Temáticas de Investigación Cooperativa en Salud-Red de Trastornos Adictivos (RETICS-RTA), Spain
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Luttrell LM, Maudsley S, Bohn LM. Fulfilling the Promise of "Biased" G Protein-Coupled Receptor Agonism. Mol Pharmacol 2015; 88:579-88. [PMID: 26134495 DOI: 10.1124/mol.115.099630] [Citation(s) in RCA: 148] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 07/01/2015] [Indexed: 12/13/2022] Open
Abstract
The fact that over 30% of current pharmaceuticals target heptahelical G protein-coupled receptors (GPCRs) attests to their tractability as drug targets. Although GPCR drug development has traditionally focused on conventional agonists and antagonists, the growing appreciation that GPCRs mediate physiologically relevant effects via both G protein and non-G protein effectors has prompted the search for ligands that can "bias" downstream signaling in favor of one or the other process. Biased ligands are novel entities with distinct signaling profiles dictated by ligand structure, and the potential prospect of biased ligands as better drugs has been pleonastically proclaimed. Indeed, preclinical proof-of-concept studies have demonstrated that both G protein and arrestin pathway-selective ligands can promote beneficial effects in vivo while simultaneously antagonizing deleterious ones. But along with opportunity comes added complexity and new challenges for drug discovery. If ligands can be biased, then ligand classification becomes assay dependent, and more nuanced screening approaches are needed to capture ligand efficacy across several dimensions of signaling. Moreover, because the signaling repertoire of biased ligands differs from that of the native agonist, unpredicted responses may arise in vivo as these unbalanced signals propagate. For any given GPCR target, establishing a framework relating in vitro efficacy to in vivo biologic response is crucial to biased drug discovery. This review discusses approaches to describing ligand efficacy in vitro, translating ligand bias into biologic response, and developing a systems-level understanding of biased agonism in vivo, with the overall goal of overcoming current barriers to developing biased GPCR therapeutics.
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Affiliation(s)
- Louis M Luttrell
- Departments of Medicine and Biochemistry & Molecular Biology, Medical University of South Carolina, Charleston, South Carolina (L.M.L.); Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina (L.M.L.); Translational Neurobiology Group, VIB Department of Molecular Genetics, Laboratory of Neurogenetics-Institute Born-Bunge, University of Antwerp, Belgium (S.M.); and Department of Molecular Therapeutics and Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida (L.M.B.)
| | - Stuart Maudsley
- Departments of Medicine and Biochemistry & Molecular Biology, Medical University of South Carolina, Charleston, South Carolina (L.M.L.); Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina (L.M.L.); Translational Neurobiology Group, VIB Department of Molecular Genetics, Laboratory of Neurogenetics-Institute Born-Bunge, University of Antwerp, Belgium (S.M.); and Department of Molecular Therapeutics and Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida (L.M.B.)
| | - Laura M Bohn
- Departments of Medicine and Biochemistry & Molecular Biology, Medical University of South Carolina, Charleston, South Carolina (L.M.L.); Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina (L.M.L.); Translational Neurobiology Group, VIB Department of Molecular Genetics, Laboratory of Neurogenetics-Institute Born-Bunge, University of Antwerp, Belgium (S.M.); and Department of Molecular Therapeutics and Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida (L.M.B.)
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Ono H, Nakamura A, Kanbara T, Minami K, Shinohara S, Sakaguchi G, Kanemasa T. Effect of the Norepinephrine Transporter (NET) Inhibition on μ-Opioid Receptor (MOR)-Induced Anti-nociception in a Bone Cancer Pain Model. J Pharmacol Sci 2014; 125:264-73. [DOI: 10.1254/jphs.14081fp] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Nakamura A, Hasegawa M, Minami K, Kanbara T, Tomii T, Nishiyori A, Narita M, Suzuki T, Kato A. Differential activation of the μ-opioid receptor by oxycodone and morphine in pain-related brain regions in a bone cancer pain model. Br J Pharmacol 2013; 168:375-88. [PMID: 22889192 DOI: 10.1111/j.1476-5381.2012.02139.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Revised: 07/31/2012] [Accepted: 08/01/2012] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE Bone cancer pain is chronic and often difficult to control with opioids. However, recent studies have shown that several opioids have distinct analgesic profiles in chronic pain. EXPERIMENTAL APPROACH To clarify the mechanisms underlying these distinct analgesic profiles, functional changes in the μ-opioid receptor were examined using a mouse femur bone cancer (FBC) model. KEY RESULTS In the FBC model, the B(max) of [(3) H]-DAMGO binding was reduced by 15-45% in the periaqueductal grey matter (PAG), region ventral to the PAG (vPAG), mediodorsal thalamus (mTH), ventral thalamus and spinal cord. Oxycodone (10(-8) -10(-5) M) and morphine (10(-8) -10(-5) M) activated [(35) S]-GTPγS binding, but the activation was significantly attenuated in the PAG, vPAG, mTH and spinal cord in the FBC model. Interestingly, the attenuation of oxycodone-induced [(35) S]-GTPγS binding was quite limited (9-26%) in comparison with that of morphine (46-65%) in the PAG, vPAG and mTH, but not in the spinal cord. Furthermore, i.c.v. oxycodone at doses of 0.02-1.0 μg per mouse clearly inhibited pain-related behaviours, such as guarding, limb-use abnormalities and allodynia-like behaviour in the FBC model mice, while i.c.v. morphine (0.05-2.0 μg per mouse) had only partial or little analgesic effect on limb-use abnormalities and allodynia-like behaviour. CONCLUSION AND IMPLICATIONS These results show that μ-opioid receptor functions are attenuated in several pain-related regions in bone cancer in an agonist-dependent manner, and suggest that modification of the μ-opioid receptor is responsible for the distinct analgesic effect of oxycodone and morphine.
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Affiliation(s)
- Atsushi Nakamura
- Pain & Neurology, Discovery Research Laboratories, Shionogi Co., Ltd, Toyonaka, Osaka, Japan
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Vernall AJ, Stoddart LA, Briddon SJ, Ng HW, Laughton CA, Doughty SW, Hill SJ, Kellam B. Conversion of a non-selective adenosine receptor antagonist into A3-selective high affinity fluorescent probes using peptide-based linkers. Org Biomol Chem 2013; 11:5673-82. [DOI: 10.1039/c3ob41221k] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Stoddart L, Vernall A, Denman J, Briddon S, Kellam B, Hill S. Fragment screening at adenosine-A(3) receptors in living cells using a fluorescence-based binding assay. CHEMISTRY & BIOLOGY 2012; 19:1105-15. [PMID: 22999879 PMCID: PMC3456874 DOI: 10.1016/j.chembiol.2012.07.014] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Revised: 06/22/2012] [Accepted: 07/17/2012] [Indexed: 10/31/2022]
Abstract
G protein-coupled receptors (GPCRs) comprise the largest family of transmembrane proteins. For GPCR drug discovery, it is important that ligand affinity is determined in the correct cellular environment and preferably using an unmodified receptor. We developed a live cell high-content screening assay that uses a fluorescent antagonist, CA200645, to determine binding affinity constants of competing ligands at human adenosine-A(1) and -A(3) receptors. This method was validated as a tool to screen a library of low molecular weight fragments, and identified a hit with submicromolar binding affinity (K(D)). This fragment was structurally unrelated to substructures of known adenosine receptor antagonists and was optimized to show selectivity for the adenosine-A(3) receptor. This technology represents a significant advance that will allow the determination of ligand and fragment affinities at receptors in their native membrane environment.
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Affiliation(s)
- Leigh A. Stoddart
- Institute of Cell Signalling, School of Biomedical Science, Queen's Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK
| | - Andrea J. Vernall
- School of Pharmacy, Centre for Biomolecular Sciences, University of Nottingham, Nottingham NG7 2RD, UK
| | - Jessica L. Denman
- Institute of Cell Signalling, School of Biomedical Science, Queen's Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK
| | - Stephen J. Briddon
- Institute of Cell Signalling, School of Biomedical Science, Queen's Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK
| | - Barrie Kellam
- School of Pharmacy, Centre for Biomolecular Sciences, University of Nottingham, Nottingham NG7 2RD, UK
| | - Stephen J. Hill
- Institute of Cell Signalling, School of Biomedical Science, Queen's Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK
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Vernall AJ, Stoddart LA, Briddon SJ, Hill SJ, Kellam B. Highly potent and selective fluorescent antagonists of the human adenosine A₃ receptor based on the 1,2,4-triazolo[4,3-a]quinoxalin-1-one scaffold. J Med Chem 2012; 55:1771-82. [PMID: 22277057 DOI: 10.1021/jm201722y] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The adenosine-A(3) receptor (A(3)AR) is a G protein-coupled receptor that shows promise as a therapeutic target for cancer, glaucoma, and various autoimmune inflammatory disorders, and as such, there is a need for molecular probes to study this receptor. Here, we report a series of fluorescent ligands containing different linkers and fluorophores based around a 1,2,4-triazolo[4,3-a]quinoxalin-1-one antagonist. One of these conjugates (19) displayed high affinity for the A(3)AR (pK(D) = 9.36 ± 0.12) and is >650-fold selective over other adenosine receptor subtypes. Confocal microscopy revealed clear, displaceable membrane labeling of CHO-A(3) cells with 19, with no detectable labeling of CHO-A(1) cells under identical conditions. This fluorescent ligand was also able to specifically label the A(3)AR in HEK293T cells containing a mixed adenosine receptor population. The subtype specificity, along with its excellent imaging properties, make 19 an ideal tool for studying A(3)AR distribution and organization, particularly in the presence of other adenosine receptor subtypes.
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Affiliation(s)
- Andrea J Vernall
- School of Pharmacy, Centre for Biomolecular Sciences, University of Nottingham, United Kingdom
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Perdonà E, Arban R, Griffante C. Distinct receptor subtypes mediate arginine vasopressin-dependent ACTH release and intracellular calcium mobilization in rat pituitary cells. Eur J Pharmacol 2012; 679:16-23. [PMID: 22285855 DOI: 10.1016/j.ejphar.2012.01.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Revised: 11/29/2011] [Accepted: 01/10/2012] [Indexed: 11/25/2022]
Abstract
In the present study, adrenocorticotropic hormone (ACTH) release and intracellular calcium ([Ca(2+)](i)) increase induced by arginine vasopressin (AVP) were characterized in collagenase-dispersed and 3-day cultured rat anterior pituitary cells. AVP and the selective vasopressin V(1b) receptor agonist, [1-deamino-4-cyclohexylalanine]AVP (d[Cha(4)]AVP) induced ACTH release with nanomolar potencies in both cell preparations, and produced a maximal stimulation that was about 1.5 fold greater in the 3-day cultured cells, indicating that the vasopressin V(1b) receptor-ACTH release pathway is enhanced over time in culture. In dispersed cells, AVP, oxytocin and d[Cha(4)]AVP induced [Ca(2+)](i) increases with nanomolar potencies. The selective vasopressin V(1a) receptors antagonist, SR49059 (100 nM), together with the selective oxytocin receptors antagonist (d(CH(2))(5)(1)Tyr(Me)(2),Thr(4),Orn(8),Tyr-NH(2)(9)-vasotocin (100 nM), inhibited the maximal AVP response by ~70%, without affecting the response to d[Cha(4)]AVP, suggesting that the V(1b) receptor was only partially responsible for the AVP-induced [Ca(2+)](i) increase. In contrast, in 3-day cultures, AVP induced an increase in [Ca(2+)](i), while oxytocin and d[Cha(4)]AVP did not. The response to AVP was completely antagonized by SR49059, whereas the vasopressin V(1b) receptor antagonists, SSR149415 and (d(CH(2))(5)(1)Tyr(Me)(2),Thr(4),Orn(8),Tyr-NH(2)(9))-vasotocin had no effect, indicating that the [Ca(2+)](i) increase was mediated exclusively by vasopressin V(1a) receptors. In conclusion, the enhancement of vasopressin V(1b) receptor-mediated ACTH release and the lack of a detectable vasopressin V(1b) receptor coupling to [Ca(2+)](i) increase in cultured cells suggests the activation of a different/additional signaling pathway in the molecular mechanism of ACTH release.
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Affiliation(s)
- Elisabetta Perdonà
- Neurosciences Centre of Excellence for Drug Discovery, GlaxoSmithKline, 37135 Verona, Italy.
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Dale CL, Hill SJ, Kellam B. New potent, short-linker BODIPY-630/650™ labelled fluorescent adenosine receptor agonists. MEDCHEMCOMM 2012. [DOI: 10.1039/c2md00247g] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Hetero-oligomerization between adenosine A₁ and thromboxane A₂ receptors and cellular signal transduction on stimulation with high and low concentrations of agonists for both receptors. Eur J Pharmacol 2011; 677:5-14. [PMID: 22200626 DOI: 10.1016/j.ejphar.2011.12.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Revised: 12/05/2011] [Accepted: 12/09/2011] [Indexed: 11/22/2022]
Abstract
Growing evidence indicates that G protein-coupled receptors can form homo- and hetero-oligomers to diversify signal transduction. However, the molecular mechanisms and physiological significance of G protein-coupled receptor-oligomers are not fully understood. Both ADOR1 (adenosine A(1) receptor) and TBXA2R (thromboxane A(2) receptor α; TPα receptor), members of the G protein-coupled receptor family, act on astrocytes and renal mesangial cells, suggesting certain functional correlations. In this study, we explored the possibility that adenosine A(1) and TPα receptors form hetero-oligomers with novel pharmacological profiles. We showed that these receptors hetero-oligomerize by conducting coimmunoprecipitation and bioluminescence resonance energy transfer (BRET(2)) assays in adenosine A(1) receptor and TPα receptor-cotransfected HEK293T cells. Furthermore, coexpression of the receptors affected signal transduction including the accumulation of cyclic AMP and phosphorylation of extracellular signal-regulated kinase-1 and -2 was significantly increased by high and low concentrations of adenosine A(1) receptor agonist and TPα agonists, respectively. Our study provides evidence of hetero-oligomerization between adenosine A(1) and TPα receptors for the first time, and suggests that this oligomerization affects signal transduction responding to different concentrations of receptor agonists.
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Wurm A, Pannicke T, Iandiev I, Francke M, Hollborn M, Wiedemann P, Reichenbach A, Osborne NN, Bringmann A. Purinergic signaling involved in Müller cell function in the mammalian retina. Prog Retin Eye Res 2011; 30:324-42. [DOI: 10.1016/j.preteyeres.2011.06.001] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Revised: 06/06/2011] [Accepted: 06/06/2011] [Indexed: 10/18/2022]
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May LT, Bridge LJ, Stoddart LA, Briddon SJ, Hill SJ. Allosteric interactions across native adenosine-A3 receptor homodimers: quantification using single-cell ligand-binding kinetics. FASEB J 2011; 25:3465-76. [PMID: 21715680 PMCID: PMC3177574 DOI: 10.1096/fj.11-186296] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A growing awareness indicates that many G-protein-coupled receptors (GPCRs) exist as homodimers, but the extent of the cooperativity across the dimer interface has been largely unexplored. Here, measurement of the dissociation kinetics of a fluorescent agonist (ABA-X-BY630) from the human A1 or A3 adenosine receptors expressed in CHO-K1 cells has provided evidence for highly cooperative interactions between protomers of the A3-receptor dimer in single living cells. In the absence of competitive ligands, the dissociation rate constants of ABA-X-BY630 from A1 and A3 receptors were 1.45 ± 0.05 and 0.57 ± 0.07 min−1, respectively. At the A3 receptor, this could be markedly increased by both orthosteric agonists and antagonists [15-, 9-, and 19-fold for xanthine amine congener (XAC), 5′-(N-ethyl carboxamido)adenosine (NECA), and adenosine, respectively] and reduced by coexpression of a nonbinding (N250A) A3-receptor mutant. The changes in ABA-X-BY630 dissociation were much lower at the A1 receptor (1.5-, 1.4-, and 1.5-fold). Analysis of the pEC50 values of XAC, NECA, and adenosine for the ABA-X-BY630-occupied A3-receptor dimer yielded values of 6.0 ± 0.1, 5.9 ± 0.1, and 5.2 ± 0.1, respectively. This study provides new insight into the spatial and temporal specificity of drug action that can be provided by allosteric modulation across a GPCR homodimeric interface.—May, L. T., Bridge, L. J., Stoddart, L. A., Briddon, S. J., Hill, S. J. Allosteric interactions across native adenosine-A3 receptor homodimers: quantification using single-cell ligand-binding kinetics.
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Affiliation(s)
- Lauren T May
- Institute of Cell Signalling, School of Biomedical Sciences, The University of Nottingham, Nottingham, UK, NG7 2UH
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Calzetta L, Spina D, Cazzola M, Page CP, Facciolo F, Rendina EA, Matera MG. Pharmacological characterization of adenosine receptors on isolated human bronchi. Am J Respir Cell Mol Biol 2011; 45:1222-31. [PMID: 21700958 DOI: 10.1165/rcmb.2011-0056oc] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Adenosine induces airways obstruction in subjects with asthma, but the receptor subtype responsible remains unknown. The objectives of this study were to determine the pharmacological profile of adenosine receptor subtypes mediating contraction and to investigate the mechanism in normal and passively sensitized human airway tissues. Contraction of bronchial rings isolated from resected lung tissue of patients with lung carcinoma was measured in response to nonselective adenosine receptor agonists, 5-AMP and 5'-(N-Ethylcarboxamido)adenosine, and A(1) receptor agonist, N(6)-cyclopentyladenosine, in the absence and presence of selective adenosine receptor antagonists. Pharmacological antagonists, chemical ablation of airway sensory nerves using capsaicin, and passive sensitization of tissue with serum from subjects with atopy and asthma was used to investigate the mechanism of contraction. Human bronchial tissue contracted in a concentration-dependent manner to adenosine agonists that showed a rank order of activity of A(1) > A(2B) >> A2(A) = A3. The maximum contractile response to N(6)-cyclopentyladenosine (231.0 ± 23.8 mg) was significantly reduced in tissues chemically treated with capsaicin to desensitize sensory nerves (desensitized: 101.6 ± 15.2 mg; P < 0.05). Passive sensitization significantly augmented the contraction induced by adenosine A(1) receptor activation (sensitized: 389.7 ± 52.8 mg versus nonsensitized; P < 0.05), which was linked to the release of leukotrienes, and not histamine (MK571: 25.5 ± 1.7 mg; epinastine 260.0 ± 22.2 mg versus control; P < 0.05). This study provides evidence for a role for adenosine A(1) receptors in eliciting human airway smooth muscle constriction, which, in part, is mediated by the action of capsaicin sensitive sensory nerves.
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Affiliation(s)
- Luigino Calzetta
- Department of Internal Medicine, University of Rome "Tor Vergata," Italy
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Verzijl D, IJzerman AP. Functional selectivity of adenosine receptor ligands. Purinergic Signal 2011; 7:171-92. [PMID: 21544511 PMCID: PMC3146648 DOI: 10.1007/s11302-011-9232-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Accepted: 04/05/2011] [Indexed: 12/11/2022] Open
Abstract
Adenosine receptors are plasma membrane proteins that transduce an extracellular signal into the interior of the cell. Basically every mammalian cell expresses at least one of the four adenosine receptor subtypes. Recent insight in signal transduction cascades teaches us that the current classification of receptor ligands into agonists, antagonists, and inverse agonists relies very much on the experimental setup that was used. Upon activation of the receptors by the ubiquitous endogenous ligand adenosine they engage classical G protein-mediated pathways, resulting in production of second messengers and activation of kinases. Besides this well-described G protein-mediated signaling pathway, adenosine receptors activate scaffold proteins such as β-arrestins. Using innovative and sensitive experimental tools, it has been possible to detect ligands that preferentially stimulate the β-arrestin pathway over the G protein-mediated signal transduction route, or vice versa. This phenomenon is referred to as functional selectivity or biased signaling and implies that an antagonist for one pathway may be a full agonist for the other signaling route. Functional selectivity makes it necessary to redefine the functional properties of currently used adenosine receptor ligands and opens possibilities for new and more selective ligands. This review focuses on the current knowledge of functionally selective adenosine receptor ligands and on G protein-independent signaling of adenosine receptors through scaffold proteins.
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Affiliation(s)
- Dennis Verzijl
- Division of Medicinal Chemistry, Leiden/Amsterdam Center for Drug Research, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands
| | - Ad P. IJzerman
- Division of Medicinal Chemistry, Leiden/Amsterdam Center for Drug Research, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands
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A novel highly selective adenosine A1 receptor agonist VCP28 reduces ischemia injury in a cardiac cell line and ischemia-reperfusion injury in isolated rat hearts at concentrations that do not affect heart rate. J Cardiovasc Pharmacol 2011; 56:282-92. [PMID: 20571427 DOI: 10.1097/fjc.0b013e3181eb8563] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The cardioprotective effects of a novel adenosine A1 receptor agonist N6-(2,2,5,5-tetramethylpyrrolidin-1-yloxyl-3-ylmethyl) adenosine (VCP28) were compared with the selective adenosine A1 receptor agonist N6-cyclopentyladenosine (CPA) in a H9c2(2-1) cardiac cell line-simulated ischemia (SI) model (12 hours) and a global ischemia (30 minutes) and reperfusion (60 minutes) model in isolated rat heart model. H9c2(2-1) cells were treated with CPA and VCP28 at the start of ischemia for entire ischemic duration, whereas isolated rat hearts were treated at the onset of reperfusion for 15 minutes. In the H9c2(2-1) cells SI model, CPA and VCP28 (100 nM) significantly (P < 0.05, n = 5-6) reduced the proportion of nonviable cells (30.88% +/- 2.49% and 16.17% +/- 3.77% of SI group, respectively) and lactate dehydrogenase efflux. In isolated rat hearts, CPA and VCP28 significantly (n = 6-8, P < 0.05) improved post-ischemic contractility (dP/dt(max), 81.69% +/- 10.96%, 91.07% +/- 19.87% of baseline, respectively), left ventricular developed pressure, and end diastolic pressure and reduced infarct size. The adenosine A1 receptor antagonist abolished the cardioprotective effects of CPA and VCP28 in SI model and isolated rat hearts. In conclusion, the adenosine A1 receptor agonist VCP28 has equal cardioprotective effects to the prototype A1 agonist CPA at concentrations that have no effect on heart rate.
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Abstract
Receptors on the surface of cells function as conduits for information flowing between the external environment and the cell interior. Since signal transduction is based on the physical interaction of receptors with both extracellular ligands and intracellular effectors, ligand binding must produce conformational changes in the receptor that can be transmitted to the intracellular domains accessible to G proteins and other effectors. Classical models of G protein-coupled receptor (GPCR) signaling envision receptor conformations as highly constrained, wherein receptors exist in equilibrium between single "off" and "on" states distinguished by their ability to activate effectors, and ligands act by perturbing this equilibrium. In such models, ligands can be classified based upon two simple parameters; affinity and efficacy, and ligand activity is independent of the assay used to detect the response. However, it is clear that GPCRs assume multiple conformations, any number of which may be capable of interacting with a discrete subset of possible effectors. Both orthosteric ligands, molecules that occupy the natural ligand-binding pocket, and allosteric modulators, small molecules or proteins that contact receptors distant from the site of ligand binding, have the ability to alter the conformational equilibrium of a receptor in ways that affect its signaling output both qualitatively and quantitatively. In this context, efficacy becomes pluridimensional and ligand classification becomes assay dependent. A more complete description of ligand-receptor interaction requires the use of multiplexed assays of receptor activation and screening assays may need to be tailored to detect specific efficacy profiles.
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Gesty-Palmer D, Luttrell LM. Refining efficacy: exploiting functional selectivity for drug discovery. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2011; 62:79-107. [PMID: 21907907 DOI: 10.1016/b978-0-12-385952-5.00009-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Early models of G protein-coupled receptor (GPCR) activation envisioned the receptor in equilibrium between unique "off" and "on" states, wherein ligand binding affected signaling by increasing or decreasing the fraction of receptors in the active conformation. It is now apparent that GPCRs spontaneously sample multiple conformations, any number of which may couple to one or more downstream effectors. Such "multistate" models imply that the receptor-ligand complex, not the receptor alone, defines which active receptor conformations predominate. "Functional selectivity" refers to the ability of a ligand to activate only a subset of its receptor's signaling repertoire. There are now numerous examples of ligands that "bias" receptor coupling between different G protein pools and non-G protein effectors such as arrestins. The type 1 parathyroid hormone receptor (PTH(1)R) is a particularly informative example, not only because of the range of biased effects that have been produced, but also because the actions of many of these ligands have been characterized in vivo. Biased PTH(1)R ligands can selectively couple the PTH(1)R to G(s) or G(q/11) pathways, with or without activating arrestin-dependent receptor desensitization and signaling. These reagents have provided insight into the contribution of different signaling pathways to PTH action in vivo and suggest it may be possible to exploit ligand bias to uncouple the anabolic effects of PTH(1)R from its catabolic and calcitropic effects. Whereas conventional agonists and antagonists only modulate the quantity of efficacy, functionally selective ligands qualitatively change GPCR signaling, offering the prospect of drugs with improved therapeutic efficacy or reduced side effects.
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Affiliation(s)
- Diane Gesty-Palmer
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA
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Rosethorne EM, Charlton SJ. Agonist-biased signaling at the histamine H4 receptor: JNJ7777120 recruits β-arrestin without activating G proteins. Mol Pharmacol 2010; 79:749-57. [PMID: 21134907 DOI: 10.1124/mol.110.068395] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The G(i/o)-coupled histamine H(4) receptor is highly expressed in hemopoietic cells and is a promising new target for the treatment of chronic inflammatory diseases. 1-[(5-Chloro-1H-indol-2-yl)carbonyl]-4-methyl-piperazine (JNJ7777120) has been described as a selective antagonist at the H(4) receptor and is widely used to characterize the physiological role of the H(4) receptor. We have investigated the pharmacological properties of JNJ7777120 using two distinct downstream signaling measurements, G protein activation and β-arrestin recruitment. The H(4) receptor agonists histamine and clobenpropit, but not JNJ7777120, were able to induce [(35)S]GTPγS binding in membranes prepared from U2OS-H(4) cells. Thioperamide, a dual H(3)/H(4) receptor antagonist, and JNJ7777120 were both able to inhibit the [(35)S]GTPγS binding induced by clobenpropit. Agonists and antagonists specific for other members of the histamine receptor family had no effect in this assay format. Histamine and clobenpropit increased β-arrestin recruitment to the H(4) receptor in a concentration-dependent manner. This β-arrestin recruitment could be inhibited by preincubation with thioperamide. We were surprised to find that preincubation with the H(4)-selective antagonist JNJ7777120 potentiated rather than antagonized the response to a submaximal concentration of clobenpropit. JNJ7777120 treatment alone resulted in an increase in β-arrestin recruitment, which again could be inhibited by preincubation with thioperamide. Schild analysis demonstrated competitive antagonism between thioperamide and both clobenpropit and JNJ7777120. Histamine and clobenpropit had comparable potencies for both [(35)S]GTPγS binding and β-arrestin recruitment, suggesting little difference in the levels of receptor reserve between the two assays. In conclusion, we have demonstrated that JNJ7777120 recruits β-arrestin to the H(4) receptor, independent of G protein activation.
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May LT, Self TJ, Briddon SJ, Hill SJ. The effect of allosteric modulators on the kinetics of agonist-G protein-coupled receptor interactions in single living cells. Mol Pharmacol 2010; 78:511-23. [PMID: 20571079 DOI: 10.1124/mol.110.064493] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Allosteric binding sites on adenosine -A(1) and -A(3) receptors represent attractive therapeutic targets for amplifying, in a spatially and temporally selective manner, the tissue protective actions of endogenous adenosine. This study has directly quantified the kinetics of agonist/G protein-coupled receptor interactions at the single-cell level, reflecting the physiological situation in which intracellular signaling proteins can exert major allosteric effects on agonist-receptor interactions. The association and dissociation rate constants at both A(1) and A(3) receptors, and therefore the affinity of the fluorescent adenosine derivative ABA-X-BY630 (structure appears in J Med Chem 50:782-793, 2007), were concentration-independent. The equilibrium dissociation constants of ABA-X-BY630 at A(1) and A(3) receptors were approximately 50 and 10 nM, respectively, suggesting that, even in live cells, low agonist concentrations predominantly detect high-affinity receptor states. At A(1) receptors, the dissociation of ABA-X-BY630 (30 nM) was significantly faster in the absence (k(off) = 1.95 +/- 0.09 min(-1)) compared with the presence of the allosteric enhancer (2-amino-4,5-dimethyl-3-thienyl)(3-(trifluoromethyl)phenyl)-methanone (PD81,723; 10 microM; k(off) = 0.80 +/- 0.03 min(-1)) and allosteric inhibitor 4-methoxy-N-(7-methyl-3-(2-pyridinyl)-1-isoquinolinyl)benzamide (VUF5455; 1 microM; k(off) = 1.48 +/- 0.16 min(-1)). In contrast, ABA-X-BY630 dissociation from A(3) receptors was significantly slower in the absence (k(off) = 0.78 +/- 0.18 min(-1)) than in the presence of the allosteric inhibitors VUF5455 (1 microM; k(off) = 3.15 +/- 0.12 min(-1)) and PD81,723 (10 microM; k(off) = 2.46 +/- 0.18 min(-1)). An allosteric mechanism of action has previously not been identified for PD81,723 at the A(3) receptor or VUF5455 at the A(1) receptor. Furthermore, the marked enhancement in fluorescent agonist dissociation by VUF5455 in living cells contrasts previous observations from broken cell preparations and emphasizes the need to study the allosteric regulation of agonist binding in living cells.
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Affiliation(s)
- Lauren T May
- The Institute of Cell Signalling, School of Biomedical Sciences, the University of Nottingham, Nottingham, United Kingdom
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Kenakin T, Miller LJ. Seven transmembrane receptors as shapeshifting proteins: the impact of allosteric modulation and functional selectivity on new drug discovery. Pharmacol Rev 2010; 62:265-304. [PMID: 20392808 DOI: 10.1124/pr.108.000992] [Citation(s) in RCA: 458] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
It is useful to consider seven transmembrane receptors (7TMRs) as disordered proteins able to allosterically respond to a number of binding partners. Considering 7TMRs as allosteric systems, affinity and efficacy can be thought of in terms of energy flow between a modulator, conduit (the receptor protein), and a number of guests. These guests can be other molecules, receptors, membrane-bound proteins, or signaling proteins in the cytosol. These vectorial flows of energy can yield standard canonical guest allostery (allosteric modification of drug effect), effects along the plane of the cell membrane (receptor oligomerization), or effects directed into the cytosol (differential signaling as functional selectivity). This review discusses these apparently diverse pharmacological effects in terms of molecular dynamics and protein ensemble theory, which tends to unify 7TMR behavior toward cells. Special consideration will be given to functional selectivity (biased agonism and biased antagonism) in terms of mechanism of action and potential therapeutic application. The explosion of technology that has enabled observation of diverse 7TMR behavior has also shown how drugs can have multiple (pluridimensional) efficacies and how this can cause paradoxical drug classification and nomenclatures.
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Affiliation(s)
- Terry Kenakin
- GlaxoSmithKline, 5 Moore Drive, Mailtstop V-287, Research Triangle Park, NC 27709, USA.
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McDonald J, Lambert DG. Binding of GTPgamma[35S] is regulated by GDP and receptor activation. Studies with the nociceptin/orphanin FQ receptor. Br J Pharmacol 2010; 159:1286-93. [PMID: 20148892 DOI: 10.1111/j.1476-5381.2009.00621.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE We have examined the effects of ligand efficacy and receptor density on the binding of guanosine 5'-[gamma-thio]triphosphate (GTPgammaS) and GDP to the nociceptin/orphanin FQ (N/OFQ) peptide receptor (NOP)-coupled G-proteins. EXPERIMENTAL APPROACH In GTPgamma[(35)S] binding experiments, using stable (CHO(hNOP)) and inducible (CHO(INDhNOP)) recombinant human and rat NOP we have measured: (i) ligand-specific GDP requirements; (ii) the effects of receptor density on guanine nucleotide affinity/capacity; and (iii) the effect of ligand efficacy on GTPgammaS association kinetics. KEY RESULTS GTPgammaS competition curves were shallow and modelled by high- and low-affinity components that were relatively consistent between cell types and tissue preparations. In the presence of 1 microM N/OFQ a high-affinity GDP binding site was also present, but the fraction of total binding was reduced. In an efficacy-dependent manner, the partial agonists [F/G]N/OFQ(1-13)NH(2) ([Phe(1)psi(CH(2)-NH)Gly(2)]-nociceptin(1-13)NH(2)) and naloxone benzoylhydrazone both reduced the fraction of high-affinity sites for GDP (relative to basal). While the pIC(50) for high-affinity GDP binding site did not decrease in the presence of 1 microM N/OFQ, N/OFQ produced a significant reduction in pIC(50) for the low-affinity site. Agonist-mediated decrease in affinity for GDP binding was efficacy-dependent. GDP displayed three affinities: high, conserved in the presence and absence of ligand; intermediate, present as a low fraction under basal conditions; low (efficacy-dependent), present during receptor activation representing the majority of binding. CONCLUSIONS AND IMPLICATIONS The affinity of GTPgamma[(35)S] was regulated by GDP and receptor activation caused increased binding of GTPgamma[(35)S] through a reduction in GDP affinity.
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Affiliation(s)
- John McDonald
- Department of Cardiovascular Sciences (Pharmacology and Therapeutics Group), Division of Anaesthesia, Critical Care and Pain Management, University of Leicester, Leicester Royal Infirmary, Leicester, UK
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Baker JG, Middleton R, Adams L, May LT, Briddon SJ, Kellam B, Hill SJ. Influence of fluorophore and linker composition on the pharmacology of fluorescent adenosine A1 receptor ligands. Br J Pharmacol 2010; 159:772-86. [PMID: 20105183 PMCID: PMC2829203 DOI: 10.1111/j.1476-5381.2009.00488.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Background and purpose: The introduction of fluorescence-based techniques, and in particular the development of fluorescent ligands, has allowed the study of G protein-coupled receptor pharmacology at the single cell and single molecule level. This study evaluated how the physicochemical nature of the linker and the fluorophore affected the pharmacological properties of fluorescent agonists and antagonists. Experimental approach: Chinese hamster ovary cells stably expressing the human adenosine A1 receptor and a cyclic 3′,5′ adenosine monophosphate response element-secreted placental alkaline phosphatase (CRE-SPAP) reporter gene, together with whole cell [3H]-8-cyclopentyl-1,3-dipropylxanthine (DPCPX) radioligand binding, were used to evaluate the pharmacological properties of a range of fluorescent ligands based on the antagonist xanthine amine congener (XAC) and the agonist 5′ (N-ethylcarboxamido) adenosine (NECA). Key results: Derivatives of NECA and XAC with different fluorophores, but equivalent linker length, showed significant differences in their binding properties to the adenosine A1 receptor. The BODIPY 630/650 derivatives had the highest affinity. Linker length also affected the pharmacological properties, depending on the fluorophore used. Particularly in fluorescent agonists, higher agonist potency could be achieved with large or small linkers for dansyl and BODIPY 630/650 derivatives, respectively. Conclusions and implications: The pharmacology of a fluorescent ligand was critically influenced by both the fluorophore and the associated linker. Furthermore, our data strongly suggest that the physicochemical properties of the fluorophore/linker pairing determine where in the environment of the target receptor the fluorophore is placed, and this, together with the environmental sensitivity of the resulting fluorescence, may finally decide its utility as a fluorescent probe. This article is part of a themed section on Imaging in Pharmacology. To view the editorial for this themed section visit http://dx.doi.org/10.1111/j.1476-5381.2010.00685.x
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Affiliation(s)
- Jillian G Baker
- Institute of Cell Signalling, School of Biomedical Sciences, Medical School, University of Nottingham, Queen's Medical Centre, Nottingham, UK
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May LT, Briddon SJ, Hill SJ. Antagonist selective modulation of adenosine A1 and A3 receptor pharmacology by the food dye Brilliant Black BN: evidence for allosteric interactions. Mol Pharmacol 2010; 77:678-86. [PMID: 20086038 DOI: 10.1124/mol.109.063065] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Allosteric binding sites on the adenosine receptor family represent potential therapeutic targets for a number of conditions involving metabolic stress. This study has identified Brilliant Black BN as a novel allosteric modulator of the adenosine A(1) and A(3) receptors. In addition to being a food dye and pharmaceutical excipient, Brilliant Black BN is commonly used within calcium mobilization assays to quench extracellular fluorescence. Brilliant Black BN (5-500 microM) had no significant effect on the calcium mobilization stimulated by the nonselective adenosine receptor agonist 5'-(N-ethylcarboxamido)adenosine in Chinese hamster ovary cells stably transfected with the human adenosine A(1) or A(3) receptor. Likewise, calcium mobilization and radioligand binding assays found that Brilliant Black BN (5-500 microM) did not significantly influence the antagonism mediated by 8-cyclopentyl-1,3-dipropylxanthine (100 nM) at the A(1) receptor. In contrast, the affinity of N-[9-chloro-2-(2-furanyl)[1,2,4]-triazolo[1,5-c]quinazolin-5-yl]benzene acetamide (MRS1220) at the A(3) receptor and xanthine amine congener (XAC) and XAC-X-BY630 at the A(1) and A(3) receptors was significantly decreased in the presence of 500 muM Brilliant Black BN. A reduction in XAC potency at the A(1) and A(3) receptor was achieved within 1 min of Brilliant Black BN addition, despite receptors having been pre-equilibrated with antagonist. Dissociation kinetics of the fluorescent XAC derivative, XAC-X-BY630, revealed that the decrease in affinity is probably due to a significant increase in dissociation rate of the antagonist in the presence of Brilliant Black BN. Taken together, these results suggest that Brilliant Black BN can act allosterically to modify ligand affinity at A(1) and A(3) receptors.
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Affiliation(s)
- L T May
- Institute of Cell Signaling, The University of Nottingham Medical School, Queen's Medical Centre, Nottingham NG7 2UH, UK
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Wurm A, Lipp S, Pannicke T, Linnertz R, Krügel U, Schulz A, Färber K, Zahn D, Grosse J, Wiedemann P, Chen J, Schöneberg T, Illes P, Reichenbach A, Bringmann A. Endogenous purinergic signaling is required for osmotic volume regulation of retinal glial cells. J Neurochem 2009; 112:1261-72. [PMID: 20002522 DOI: 10.1111/j.1471-4159.2009.06541.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Intense neuronal activity in the sensory retina is associated with a volume increase of neuronal cells (Uckermann et al., J. Neurosci. 2004, 24:10149) and a decrease in the osmolarity of the extracellular space fluid (Dmitriev et al., Vis. Neurosci. 1999, 16:1157). Here, we show the existence of an endogenous purinergic mechanism that prevents hypoosmotic swelling of retinal glial (Müller) cells in mice. In contrast to the cells from wild-type mice, hypoosmotic stress induced rapid swelling of glial cell somata in retinal slices from mice deficient in P2Y(1), adenosine A(1) receptors, or ecto-5'-nucleotidase (CD73). Consistently, glial cell bodies in retinal slices from wild-type mice displayed osmotic swelling when P2Y(1) or A(1) receptors, or CD73, were pharmacologically blocked. Exogenous ATP, UTP, and UDP inhibited glial swelling in retinal slices, while the swelling of isolated glial cells was prevented by ATP but not by UTP or UDP, suggesting that uracil nucleotides indirectly regulate the glial cell volume via activation of neuronal P2Y(4/6) and neuron-to-glia signaling. It is suggested that autocrine/paracrine activation of purinergic receptors and enzymes is crucially involved in the regulation of the glial cell volume.
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Affiliation(s)
- Antje Wurm
- Paul Flechsig Institute of Brain Research, University of Leipzig, Leipzig, Germany
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41
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Horinouchi T, Asano H, Higa T, Nishimoto A, Nishiya T, Muramatsu I, Miwa S. Differential coupling of human endothelin type A receptor to G(q/11) and G(12) proteins: the functional significance of receptor expression level in generating multiple receptor signaling. J Pharmacol Sci 2009; 111:338-51. [PMID: 19942800 DOI: 10.1254/jphs.09233fp] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
This study examines the influence of receptor expression level on signaling pathways activated via endothelin type A receptor (ET(A)R) expressed in Chinese hamster ovary cells at 32,100 (ET(A)R-high-CHO) and 893 (ET(A)R-low-CHO) fmolmg protein(-1). Endothelin-1 (ET-1) elicited a sustained increase in intracellular Ca(2+) concentration ([Ca(2+)](i)), which was dependent on G(q/11) protein, phospholipase C (PLC), Na(+)/H(+) exchanger (NHE), and p38 mitogen-activated protein kinase (p38MAPK) in ET(A)R-high-CHO, whereas the sustained [Ca(2+)](i) increase was negligible in ET(A)R-low-CHO. Functional study with Cytosensor(TM) microphysiometer showed that ET-1 evoked an NHE1-mediated increase in extracellular acidification rate (ECAR) in ET(A)R-high-CHO and ET(A)R-low-CHO. In ET(A)R-high-CHO, the ECAR response at 30 min after ET-1 stimulation was insensitive to G(q/11) and PLC inhibitors, but sensitive to the p38MAPK inhibitor. In ET(A)R-low-CHO, the ECAR response at 30 min was sensitive to these inhibitors. Western blot analysis demonstrated that ET-1-induced p38MAPK phosphorylation in ET(A)R-low-CHO but not in ET(A)R-high-CHO was mediated via G(q/11) and PLC. The G(q/11)/PLC-independent p38MAPK phosphorylation in ET(A)R-high-CHO was suppressed by expression of the C terminus of G(alpha12) protein to disrupt receptor-G(12) protein coupling. These results provide evidence for multiple signaling pathways of ET(A)R that were activated via at least the G(q/11)/PLC/NHE, G(12)/p38MAPK/NHE, and G(q/11)/PLC/p38MAPK/NHE cascades in an expression level-dependent manner.
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Affiliation(s)
- Takahiro Horinouchi
- Department of Cellular Pharmacology, Hokkaido University Graduate School of Medicine, Japan
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Stewart GD, Valant C, Dowell SJ, Mijaljica D, Devenish RJ, Scammells PJ, Sexton PM, Christopoulos A. Determination of adenosine A1 receptor agonist and antagonist pharmacology using Saccharomyces cerevisiae: implications for ligand screening and functional selectivity. J Pharmacol Exp Ther 2009; 331:277-86. [PMID: 19641164 DOI: 10.1124/jpet.109.158667] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The budding yeast, Saccharomyces cerevisiae, is a convenient system for coupling heterologous G protein-coupled receptors (GPCRs) to the pheromone response pathway to facilitate empirical ligand screening and/or GPCR mutagenesis studies. However, few studies have applied this system to define GPCR-G protein-coupling preferences and furnish information on ligand affinities, efficacies, and functional selectivity. We thus used different S. cerevisiae strains, each expressing a specific human Galpha/yeast Gpa1 protein chimera, and determined the pharmacology of various ligands of the coexpressed human adenosine A(1) receptor. These assays, in conjunction with the application of quantitative models of agonism and antagonism, revealed that (-)-N(6)-(2-phenylisopropyl)adenosine was a high-efficacy agonist that selectively coupled to Gpa/1Galpha(o), Gpa1/Galpha(i1/2), and Gpa1/Galpha(i3), whereas the novel compound, 5'-deoxy-N(6)-(endo-norborn-2-yl)-5'-(2-fluorophenylthio)adenosine (VCP-189), was a lower-efficacy agonist that selectively coupled to Gpa1/Galpha(i) proteins; the latter finding suggested that VCP-189 might be functionally selective. The affinity of the antagonist, 8-cyclopentyl-1,3-dipropylxanthine, was also determined at the various strains. Subsequent experiments performed in mammalian Chinese hamster ovary cells monitoring cAMP formation/inhibition, intracellular calcium mobilization, phosphorylation of extracellular signal-regulated kinase 1 and 2 or (35)S-labeled guanosine 5'-(gamma-thio)triphosphate binding, were in general agreement with the yeast data regarding agonist efficacy estimation and antagonist affinity estimation, but revealed that the apparent functional selectivity of VCP-189 could be explained by differences in stimulus-response coupling between yeast and mammalian cells. Our results suggest that this yeast system is a useful tool for quantifying ligand affinity and relative efficacy, but it may lack the sensitivity required to detect functional selectivity of low-efficacy agonists.
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Affiliation(s)
- Gregory D Stewart
- Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia
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Jongsma M, van Unen J, van Loenen PB, Michel MC, Peters SLM, Alewijnse AE. Different response patterns of several ligands at the sphingosine-1-phosphate receptor subtype 3 (S1P(3)). Br J Pharmacol 2009; 156:1305-11. [PMID: 19309361 DOI: 10.1111/j.1476-5381.2009.00134.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE Recently, some ligands targeting the sphingosine-1-phosphate receptor subtype 3 (S1P(3)) have become available. The characterization of these compounds was mainly based on one functional read-out system, although S1P(3) receptors are known to activate different signal transduction pathways. Therefore, this study pharmacologically characterizes these compounds using different assays. EXPERIMENTAL APPROACH Using CHO-FlpIn cells expressing the human S1P(3) receptor the potencies and maximal effects of S1P, FTY720-P, VPC23019, VPC23153 and VPC24191 were determined in three different assays [inhibition of cAMP accumulation, elevation of intracellular calcium concentrations ([Ca(2+)](i)) and S1P(3) receptor internalization]. KEY RESULTS All compounds tested inhibited forskolin-induced cAMP accumulation, increased [Ca(2+)](i) and induced S1P(3) receptor internalization but with different potencies and maximal effects. S1P was the most potent compound in all assays followed by FTY720-P. The VPC compounds were generally less potent than S1P and FTY720-P. Regarding the maximal effects, all compounds except VPC23153, behaved as full agonists in the cAMP accumulation assay. In the calcium assay, FTY720-P, VPC23019 and VPC24191 displayed partial and VPC23153 weak partial agonist activity, relative to S1P. Interestingly, treatment with the G(i) inactivator Pertussis toxin, did not affect S1P-induced [Ca(2+)](i) elevations but inhibited those in response to the other compounds, by about 50%. CONCLUSIONS AND IMPLICATIONS This study demonstrated differential response patterns at the S1P(3) receptor for a range of ligands. These differences could indicate the presence of functional selectivity at this receptor as FTY720-P and the VPC compounds seemed to signal predominantly via G(i)- whereas S1P activated G(i) and G(q)-coupled pathways.
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Affiliation(s)
- M Jongsma
- Department of Pharmacology & Pharmacotherapy, Academic Medical Center, Amsterdam, The Netherlands
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Mathematical modeling and application of genetic algorithm to parameter estimation in signal transduction: Trafficking and promiscuous coupling of G-protein coupled receptors. Comput Biol Med 2008; 38:574-82. [DOI: 10.1016/j.compbiomed.2008.02.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2007] [Accepted: 02/09/2008] [Indexed: 11/18/2022]
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Internalization and desensitization of adenosine receptors. Purinergic Signal 2007; 4:21-37. [PMID: 18368531 PMCID: PMC2245999 DOI: 10.1007/s11302-007-9086-7] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2007] [Accepted: 10/02/2007] [Indexed: 01/28/2023] Open
Abstract
Until now, more than 800 distinct G protein-coupled receptors (GPCRs) have been identified in the human genome. The four subtypes of the adenosine receptor (A1, A2A, A2B and A3 receptor) belong to this large family of GPCRs that represent the most widely targeted pharmacological protein class. Since adenosine receptors are widespread throughout the body and involved in a variety of physiological processes and diseases, there is great interest in understanding how the different subtypes are regulated, as a basis for designing therapeutic drugs that either avoid or make use of this regulation. The major GPCR regulatory pathway involves phosphorylation of activated receptors by G protein-coupled receptor kinases (GRKs), a process that is followed by binding of arrestin proteins. This prevents receptors from activating downstream heterotrimeric G protein pathways, but at the same time allows activation of arrestin-dependent signalling pathways. Upon agonist treatment, adenosine receptor subtypes are differently regulated. For instance, the A1Rs are not (readily) phosphorylated and internalize slowly, showing a typical half-life of several hours, whereas the A2AR and A2BR undergo much faster downregulation, usually shorter than 1 h. The A3R is subject to even faster downregulation, often a matter of minutes. The fast desensitization of the A3R after agonist exposure may be therapeutically equivalent to antagonist occupancy of the receptor. This review describes the process of desensitization and internalization of the different adenosine subtypes in cell systems, tissues and in vivo studies. In addition, molecular mechanisms involved in adenosine receptor desensitization are discussed.
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Cordeaux Y, Briddon SJ, Alexander SPH, Kellam B, Hill SJ. Agonist-occupied A3 adenosine receptors exist within heterogeneous complexes in membrane microdomains of individual living cells. FASEB J 2007; 22:850-60. [PMID: 17959910 DOI: 10.1096/fj.07-8180com] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
G protein-coupled receptors are known to be organized within different membrane compartments or microdomains of individual cells. Here, we have used a fluorescent A3 adenosine receptor (A3-AR) agonist, ABEA-X-BY630, and the technique of fluorescence correlation spectroscopy (FCS) to investigate the diffusional characteristics of functional agonist-occupied A3-AR complexes in single living cells. In Chinese hamster ovary cells expressing the human A3-AR, the fluorescent A3-AR agonist was able to inhibit forskolin-stimulated [3H]cAMP production (pEC50=8.57), and this was antagonized by the A3-selective antagonist MRS1220 (pK(B)=9.32). The fluorescent ligand also stimulated phosphoinositide hydrolysis (pEC50=7.34). Ligand binding to the A3-AR on the membranes of single cells and subsequent increases in single cell [Ca2+]i were monitored simultaneously in real time using confocal microscopy. FCS measurements in small-membrane microdomains (approximately 0.2 microm2) revealed two agonist-occupied A3-AR components with differing diffusion characteristics (diffusion coefficients=2.65x10(-8) and 1.19x10(-9) cm2/s, respectively). The binding of ligand to these two components was reduced from 5.1 and 14.9 to 2.6 and 3.3 receptors/microm2, respectively, by MRS1220 (100 nM). These data provide direct evidence for at least two populations of agonist-occupied A3-receptor complexes, showing different motilities within the membrane of single living cells.
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Affiliation(s)
- Y Cordeaux
- Institute of Cell Signalling, School of Biomedical Sciences, Medical School, University of Nottingham, Nottingham, NG7 2UH, UK
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Baker JG, Hill SJ. Multiple GPCR conformations and signalling pathways: implications for antagonist affinity estimates. Trends Pharmacol Sci 2007; 28:374-81. [PMID: 17629959 PMCID: PMC2169386 DOI: 10.1016/j.tips.2007.06.011] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2007] [Revised: 05/22/2007] [Accepted: 06/26/2007] [Indexed: 01/27/2023]
Abstract
Antagonist affinity measurements have traditionally been considered important in characterizing the cell-surface receptors present in a particular cell or tissue. A central assumption has been that antagonist affinity is constant for a given receptor-antagonist interaction, regardless of the agonist used to stimulate that receptor or the downstream response that is measured. As a consequence, changes in antagonist affinity values have been taken as initial evidence for the presence of novel receptor subtypes. Emerging evidence suggests, however, that receptors can possess multiple binding sites and the same receptor can show different antagonist affinity measurements under distinct experimental conditions. Here, we discuss several mechanisms by which antagonists have different affinities for the same receptor as a consequence of allosterism, coupling to different G proteins, multiple (but non-interacting) receptor sites, and signal-pathway-dependent pharmacology (where the pharmacology observed varies depending on the signalling pathway measured).
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Middleton RJ, Briddon SJ, Cordeaux Y, Yates AS, Dale CL, George MW, Baker JG, Hill SJ, Kellam B. New fluorescent adenosine A1-receptor agonists that allow quantification of ligand-receptor interactions in microdomains of single living cells. J Med Chem 2007; 50:782-93. [PMID: 17249651 DOI: 10.1021/jm061279i] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Fluorescence spectroscopy is becoming a valuable addition to the array of techniques available for scrutinizing ligand-receptor interactions in biological systems. In particular, scanning confocal microscopy and fluorescence correlation spectroscopy (FCS) allow the noninvasive imaging and quantification of these interactions in single living cells. To address the emerging need for fluorescently labeled ligands to support these technologies, we have developed a series of red-emitting agonists for the human adenosine A1-receptor that, collectively, are N6-aminoalkyl derivatives of adenosine or adenosine 5'-N-ethyl carboxamide. The agonists, which incorporate the commercially available fluorophore BODIPY [630/650], retain potent and efficacious agonist activity, as demonstrated by their ability to inhibit cAMP accumulation in chinese hamster ovary cells expressing the human adenosine A1-receptor. Visualization and confirmation of ligand-receptor interactions at the cell membrane were accomplished using confocal microscopy, and their suitability for use in FCS was demonstrated by quantification of agonist binding in small areas of cell membrane.
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Affiliation(s)
- Richard J Middleton
- School of Pharmacy, Centre for Biomolecular Sciences, and School of Chemistry, University of Nottingham, University Park, Nottingham, United Kingdom
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Kenakin T. Collateral efficacy as a pharmacological problem applied to new drug discovery. Expert Opin Drug Discov 2006; 1:635-52. [DOI: 10.1517/17460441.1.7.635] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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50
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Self TJ, Oakley SM, Hill SJ. Clathrin-independent internalization of the human histamine H1-receptor in CHO-K1 cells. Br J Pharmacol 2006; 146:612-24. [PMID: 16086035 PMCID: PMC1751180 DOI: 10.1038/sj.bjp.0706337] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The aim of the present study was to investigate the cellular pathway involved in histamine-stimulated internalization of the human H1-receptor in CHO-K1 cells expressing N-terminal myc-tagged H1-receptor (Myc-H1) or N-terminal myc-C-terminal green fluorescent protein (Myc-GFP H1) versions of the receptor. Studies of 3H-mepyramine binding and histamine-stimulated 3H-inositol phosphate accumulation in these cells showed that the Myc-H1 and Myc-GFP H1-receptors had identical pharmacology to the wild-type H1-receptor. The Myc-H1-receptor was rapidly internalized in CHO-K1 cells following stimulation with histamine (0.1 mM). This response occurred within 15 min, and could be prevented by the quaternary H1-receptor antagonist alpha-pirdonium. Similar data were obtained with the Myc-GFP H1-receptors. Internalization of the Myc-GFP H1-receptor was maintained in the absence of extracellular calcium and was not inhibited by the CAM kinase II inhibitor KN-62 (10 microM). Phorbol dibutyrate, an activator of protein kinase C, was also able to stimulate internalization of the H1-receptor. However, inhibition or downregulation of protein kinase C (which significantly modified histamine-stimulated inositol phosphate responses) was without effect on the internalization of the H1-receptor stimulated by histamine. Hypertonic sucrose did not prevent histamine-induced internalization of the Myc-GFP H1-receptor, but was able to attenuate internalization of transferrin via clathrin-mediated endocytosis in the same cells. In contrast, preincubation of cells with filipin or nystatin, which disrupts caveolae and lipid rafts, completely inhibited the histamine-induced internalization of the Myc-GFP H1-receptor, but was without effect on the sequestration of transferrin. The H1-receptor and cholera toxin subunit B were colocalized under resting conditions at the cell surface. Immunohistochemical studies with an antibody to caveolin-1 confirmed that this protein was also localized predominantly to the plasma membrane. However, following stimulation of CHO-Myc-GFP H1 cells with histamine, there was no evidence for internalization of caveolin-1 in parallel with the H1-receptor. These data provide strong evidence that the H1-receptor is internalized via a clathrin-independent mechanism and most likely involves lipid rafts.
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Affiliation(s)
- Timothy J Self
- Institute of Cell Signalling, Medical School, Queen's Medical Centre, University of Nottingham, Nottingham NG7 2UH
| | - Sarah M Oakley
- Institute of Cell Signalling, Medical School, Queen's Medical Centre, University of Nottingham, Nottingham NG7 2UH
| | - Stephen J Hill
- Institute of Cell Signalling, Medical School, Queen's Medical Centre, University of Nottingham, Nottingham NG7 2UH
- Author for correspondence:
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