51
|
Gaitonde SA, González-Maeso J. Contribution of heteromerization to G protein-coupled receptor function. Curr Opin Pharmacol 2016; 32:23-31. [PMID: 27835800 DOI: 10.1016/j.coph.2016.10.006] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 10/22/2016] [Accepted: 10/24/2016] [Indexed: 12/22/2022]
Abstract
G protein-coupled receptors (GPCRs) are a remarkably multifaceted family of transmembrane proteins that exert a variety of physiological effects. Although family A GPCRs are able to operate as monomers, there is increasing evidence that heteromerization represents a fundamental aspect of receptor function, trafficking and pharmacology. Most recently, it has been suggested that GPCR heteromers may play a crucial role as new molecular targets of heteromer-selective and bivalent ligands. The current review summarizes key recent developments in these topics.
Collapse
Affiliation(s)
- Supriya A Gaitonde
- Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, United States
| | - Javier González-Maeso
- Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, United States.
| |
Collapse
|
52
|
Morrow JM, Lazic S, Dixon Fox M, Kuo C, Schott RK, de A Gutierrez E, Santini F, Tropepe V, Chang BSW. A second visual rhodopsin gene, rh1-2, is expressed in zebrafish photoreceptors and found in other ray-finned fishes. ACTA ACUST UNITED AC 2016; 220:294-303. [PMID: 27811293 DOI: 10.1242/jeb.145953] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 10/25/2016] [Indexed: 12/19/2022]
Abstract
Rhodopsin (rh1) is the visual pigment expressed in rod photoreceptors of vertebrates that is responsible for initiating the critical first step of dim-light vision. Rhodopsin is usually a single copy gene; however, we previously discovered a novel rhodopsin-like gene expressed in the zebrafish retina, rh1-2, which we identified as a functional photosensitive pigment that binds 11-cis retinal and activates in response to light. Here, we localized expression of rh1-2 in the zebrafish retina to a subset of peripheral photoreceptor cells, which indicates a partially overlapping expression pattern with rh1 We also expressed, purified and characterized Rh1-2, including investigation of the stability of the biologically active intermediate. Using fluorescence spectroscopy, we found the half-life of the rate of retinal release of Rh1-2 following photoactivation to be more similar to that of the visual pigment rhodopsin than to the non-visual pigment exo-rhodopsin (exorh), which releases retinal around 5 times faster. Phylogenetic and molecular evolutionary analyses show that rh1-2 has ancient origins within teleost fishes, is under similar selective pressure to rh1, and likely experienced a burst of positive selection following its duplication and divergence from rh1 These findings indicate that rh1-2 is another functional visual rhodopsin gene, which contradicts the prevailing notion that visual rhodopsin is primarily found as a single copy gene within ray-finned fishes. The reasons for retention of this duplicate gene, as well as possible functional consequences for the visual system, are discussed.
Collapse
Affiliation(s)
- James M Morrow
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada, M5S 3G5.,Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada, M5S 3B2
| | - Savo Lazic
- Department of Molecular Genetics, University of Toronto, Toronto, Canada, M5S 1A8
| | - Monica Dixon Fox
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada, M5S 3G5
| | - Claire Kuo
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada, M5S 3G5
| | - Ryan K Schott
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada, M5S 3B2
| | - Eduardo de A Gutierrez
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada, M5S 3B2
| | - Francesco Santini
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Vincent Tropepe
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada, M5S 3G5.,Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Canada, M5T 3A9.,Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, Canada, M5S 3B2
| | - Belinda S W Chang
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada, M5S 3G5 .,Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada, M5S 3B2.,Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, Canada, M5S 3B2
| |
Collapse
|
53
|
Quaternary structures of opsin in live cells revealed by FRET spectrometry. Biochem J 2016; 473:3819-3836. [PMID: 27623775 DOI: 10.1042/bcj20160422] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 09/12/2016] [Indexed: 02/06/2023]
Abstract
Rhodopsin is a prototypical G-protein-coupled receptor (GPCR) that initiates phototransduction in the retina. The receptor consists of the apoprotein opsin covalently linked to the inverse agonist 11-cis retinal. Rhodopsin and opsin have been shown to form oligomers within the outer segment disc membranes of rod photoreceptor cells. However, the physiological relevance of the observed oligomers has been questioned since observations were made on samples prepared from the retina at low temperatures. To investigate the oligomeric status of opsin in live cells at body temperatures, we utilized a novel approach called Förster resonance energy transfer spectrometry, which previously has allowed the determination of the stoichiometry and geometry (i.e. quaternary structure) of various GPCRs. In the current study, we have extended the method to additionally determine whether or not a mixture of oligomeric forms of opsin exists and in what proportion. The application of this improved method revealed that opsin expressed in live Chinese hamster ovary (CHO) cells at 37°C exists as oligomers of various sizes. At lower concentrations, opsin existed in an equilibrium of dimers and tetramers. The tetramers were in the shape of a near-rhombus. At higher concentrations of the receptor, higher-order oligomers began to form. Thus, a mixture of different oligomeric forms of opsin is present in the membrane of live CHO cells and oligomerization occurs in a concentration-dependent manner. The general principles underlying the concentration-dependent oligomerization of opsin may be universal and apply to other GPCRs as well.
Collapse
|
54
|
Liu H, Tian Y, Ji B, Lu H, Xin Q, Jiang Y, Ding L, Zhang J, Chen J, Bai B. Heterodimerization of the kappa opioid receptor and neurotensin receptor 1 contributes to a novel β-arrestin-2-biased pathway. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:2719-2738. [PMID: 27523794 DOI: 10.1016/j.bbamcr.2016.07.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 07/28/2016] [Accepted: 07/29/2016] [Indexed: 12/17/2022]
Abstract
Together with its endogenous ligands (dynorphin), the kappa opioid receptor (KOR) plays an important role in modulating various physiological and pharmacological responses, with a classical G protein-coupled pathway mediating analgesia and non-G protein-dependent pathway, especially the β-arrestin-dependent pathway, eliciting side effects of dysphoria, aversion, drug-seeking in addicts, or even relapse to addiction. Although mounting evidence has verified a functional overlap between dynorphin/KOR and neurotensin/neurotensin receptor 1 (NTSR1) systems, little is known about direct interaction between the two receptors. Here, we showed that KOR and NTSR1 form a heterodimer that functions as a novel pharmacological entity, and this heterodimer, in turn, brings about a switch in KOR-mediated signal transduction, from G protein-dependent to β-arrestin-2-dependent. This was simultaneously verified by analyzing a KOR mutant (196th residue) that lost the ability to dimerize with NTSR1. We also found that dual occupancy of the heterodimer forced the β-arrestin-2-dependent pathway back into Gi protein-dependent signaling, according to KOR activation. These data provide new insights into the interaction between KOR and NTSR1, and the newly discovered role of NTSR1 acting as a switch between G protein- and β-arrestin-dependent pathways of KOR also suggests a new approach for utilizing pathologically elevated dynorphin/KOR system into full play for its analgesic effect with limited side effects.
Collapse
Affiliation(s)
- Haiqing Liu
- School of Life Science, Shandong Agricultural University, Taian, Shandong 271018, PR China; Department of Physiology, Taishan Medical College, Taian, Shandong 271000, PR China.
| | - Yanjun Tian
- Neurobiology Institute, Jining Medical University, Jining, Shandong 272067, PR China.
| | - Bingyuan Ji
- Neurobiology Institute, Jining Medical University, Jining, Shandong 272067, PR China.
| | - Hai Lu
- Neurobiology Institute, Jining Medical University, Jining, Shandong 272067, PR China.
| | - Qing Xin
- Neurobiology Institute, Jining Medical University, Jining, Shandong 272067, PR China.
| | - Yunlu Jiang
- Neurobiology Institute, Jining Medical University, Jining, Shandong 272067, PR China.
| | - Liangcai Ding
- Neurobiology Institute, Jining Medical University, Jining, Shandong 272067, PR China.
| | - Jingmei Zhang
- Neurobiology Institute, Jining Medical University, Jining, Shandong 272067, PR China.
| | - Jing Chen
- Neurobiology Institute, Jining Medical University, Jining, Shandong 272067, PR China; Division of Translational and Systems, Warwick Medical School, University of Warwick, Coventry, UK.
| | - Bo Bai
- Neurobiology Institute, Jining Medical University, Jining, Shandong 272067, PR China.
| |
Collapse
|
55
|
Hübner H, Schellhorn T, Gienger M, Schaab C, Kaindl J, Leeb L, Clark T, Möller D, Gmeiner P. Structure-guided development of heterodimer-selective GPCR ligands. Nat Commun 2016; 7:12298. [PMID: 27457610 PMCID: PMC4963535 DOI: 10.1038/ncomms12298] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2015] [Accepted: 06/16/2016] [Indexed: 12/18/2022] Open
Abstract
Crystal structures of G protein-coupled receptor (GPCR) ligand complexes allow a rational design of novel molecular probes and drugs. Here we report the structure-guided design, chemical synthesis and biological investigations of bivalent ligands for dopamine D2 receptor/neurotensin NTS1 receptor (D2R/NTS1R) heterodimers. The compounds of types 1–3 consist of three different D2R pharmacophores bound to an affinity-generating lipophilic appendage, a polyethylene glycol-based linker and the NTS1R agonist NT(8-13). The bivalent ligands show binding affinity in the picomolar range for cells coexpressing both GPCRs and unprecedented selectivity (up to three orders of magnitude), compared with cells that only express D2Rs. A functional switch is observed for the bivalent ligands 3b,c inhibiting cAMP formation in cells singly expressing D2Rs but stimulating cAMP accumulation in D2R/NTS1R-coexpressing cells. Moreover, the newly synthesized bivalent ligands show a strong, predominantly NTS1R-mediated β-arrestin-2 recruitment at the D2R/NTS1R-coexpressing cells. G protein-coupled receptors (GPCRs) are involved in key signalling pathways and represent important targets for the treatment of neurological and psychiatric disorders. Here, the authors describe powerful bivalent ligands that efficiently bind to therapeutically relevant GPCR heterodimers
Collapse
Affiliation(s)
- Harald Hübner
- Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich-Alexander-Universität Erlangen-Nürnberg, Schuhstraße 19, Erlangen 91052, Germany
| | - Tamara Schellhorn
- Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich-Alexander-Universität Erlangen-Nürnberg, Schuhstraße 19, Erlangen 91052, Germany
| | - Marie Gienger
- Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich-Alexander-Universität Erlangen-Nürnberg, Schuhstraße 19, Erlangen 91052, Germany
| | - Carolin Schaab
- Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich-Alexander-Universität Erlangen-Nürnberg, Schuhstraße 19, Erlangen 91052, Germany
| | - Jonas Kaindl
- Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich-Alexander-Universität Erlangen-Nürnberg, Schuhstraße 19, Erlangen 91052, Germany.,Department of Chemistry and Pharmacy, Computer-Chemie-Center, Friedrich-Alexander-Universität Erlangen-Nürnberg, Nägelsbachstraße 25, Erlangen 91052, Germany
| | - Laurin Leeb
- Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich-Alexander-Universität Erlangen-Nürnberg, Schuhstraße 19, Erlangen 91052, Germany
| | - Timothy Clark
- Department of Chemistry and Pharmacy, Computer-Chemie-Center, Friedrich-Alexander-Universität Erlangen-Nürnberg, Nägelsbachstraße 25, Erlangen 91052, Germany.,Centre for Molecular Design, University of Portsmouth, King Henry Building, Portsmouth PO1 2DY, UK
| | - Dorothee Möller
- Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich-Alexander-Universität Erlangen-Nürnberg, Schuhstraße 19, Erlangen 91052, Germany
| | - Peter Gmeiner
- Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich-Alexander-Universität Erlangen-Nürnberg, Schuhstraße 19, Erlangen 91052, Germany
| |
Collapse
|
56
|
Kleinau G, Müller A, Biebermann H. Oligomerization of GPCRs involved in endocrine regulation. J Mol Endocrinol 2016; 57:R59-80. [PMID: 27151573 DOI: 10.1530/jme-16-0049] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 05/04/2016] [Indexed: 12/27/2022]
Abstract
More than 800 different human membrane-spanning G-protein-coupled receptors (GPCRs) serve as signal transducers at biological barriers. These receptors are activated by a wide variety of ligands such as peptides, ions and hormones, and are able to activate a diverse set of intracellular signaling pathways. GPCRs are of central importance in endocrine regulation, which underpins the significance of comprehensively studying these receptors and interrelated systems. During the last decade, the capacity for multimerization of GPCRs was found to be a common and functionally relevant property. The interaction between GPCR monomers results in higher order complexes such as homomers (identical receptor subtype) or heteromers (different receptor subtypes), which may be present in a specific and dynamic monomer/oligomer equilibrium. It is widely accepted that the oligomerization of GPCRs is a mechanism for determining the fine-tuning and expansion of cellular processes by modification of ligand action, expression levels, and related signaling outcome. Accordingly, oligomerization provides exciting opportunities to optimize pharmacological treatment with respect to receptor target and tissue selectivity or for the development of diagnostic tools. On the other hand, GPCR heteromerization may be a potential reason for the undesired side effects of pharmacological interventions, faced with numerous and common mutual signaling modifications in heteromeric constellations. Finally, detailed deciphering of the physiological occurrence and relevance of specific GPCR/GPCR-ligand interactions poses a future challenge. This review will tackle the aspects of GPCR oligomerization with specific emphasis on family A GPCRs involved in endocrine regulation, whereby only a subset of these receptors will be discussed in detail.
Collapse
Affiliation(s)
- Gunnar Kleinau
- Institute of Experimental Pediatric Endocrinology (IEPE)Charité-Universitätsmedizin, Berlin, Germany
| | - Anne Müller
- Institute of Experimental Pediatric Endocrinology (IEPE)Charité-Universitätsmedizin, Berlin, Germany
| | - Heike Biebermann
- Institute of Experimental Pediatric Endocrinology (IEPE)Charité-Universitätsmedizin, Berlin, Germany
| |
Collapse
|
57
|
Zangrandi L, Burtscher J, MacKay JP, Colmers WF, Schwarzer C. The G-protein biased partial κ opioid receptor agonist 6'-GNTI blocks hippocampal paroxysmal discharges without inducing aversion. Br J Pharmacol 2016; 173:1756-67. [PMID: 26928671 PMCID: PMC4867738 DOI: 10.1111/bph.13474] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 02/05/2016] [Accepted: 02/09/2016] [Indexed: 11/29/2022] Open
Abstract
Background and Purpose With a prevalence of 1–2%, epilepsies belong to the most frequent neurological diseases worldwide. Although antiepileptic drugs are available since several decades, the incidence of patients that are refractory to medication is still over 30%. Antiepileptic effects of κ opioid receptor (κ receptor) agonists have been proposed since the 1980s. However, their clinical use was hampered by dysphoric side effects. Recently, G‐protein biased κ receptor agonists were developed, suggesting reduced aversive effects. Experimental Approach We investigated the effects of the κ receptor agonist U‐50488H and the G‐protein biased partial κ receptor agonist 6′‐GNTI in models of acute seizures and drug‐resistant temporal lobe epilepsy and in the conditioned place avoidance (CPA) test. Moreover, we performed slice electrophysiology to understand the functional mechanisms of 6′‐GNTI. Key Results As previously shown for U‐50488H, 6′‐GNTI markedly increased the threshold for pentylenetetrazole‐induced seizures. All treated mice displayed reduced paroxysmal activity in response to U‐50488H (20 mg·kg−1) or 6′‐GNTI (10–30 nmoles) treatment in the mouse model of intra‐hippocampal injection of kainic acid. Single cell recordings on hippocampal pyramidal cells revealed enhanced inhibitory signalling as potential mechanisms causing the reduction of paroxysmal activity. Effects of 6′‐GNTI were blocked in both seizure models by the κ receptor antagonist 5′‐GNTI. Moreover, 6′‐GNTI did not induce CPA, a measure of aversive effects, while U‐50488H did. Conclusions and Implications Our data provide the proof of principle that anticonvulsant/antiseizure and aversive effects of κ receptor activation can be pharmacologically separated in vivo.
Collapse
Affiliation(s)
- Luca Zangrandi
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | - Johannes Burtscher
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | - James P MacKay
- Department of Pharmacology, University of Alberta, Edmonton, AB, Canada
| | - William F Colmers
- Department of Pharmacology, University of Alberta, Edmonton, AB, Canada
| | - Christoph Schwarzer
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| |
Collapse
|
58
|
Huang YH, Su YS, Chang CJ, Sun WH. Heteromerization of G2A and OGR1 enhances proton sensitivity and proton-induced calcium signals. J Recept Signal Transduct Res 2016; 36:633-644. [PMID: 27049592 DOI: 10.3109/10799893.2016.1155064] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Proton-sensing G-protein-coupled receptors (GPCRs; OGR1, GPR4, G2A, TDAG8), with full activation at pH 6.4 ∼ 6.8, are important to pH homeostasis, immune responses and acid-induced pain. Although G2A mediates the G13-Rho pathway in response to acid, whether G2A activates Gs, Gi or Gq proteins remains debated. In this study, we examined the response of this fluorescence protein-tagged OGR1 family to acid stimulation in HEK293T cells. G2A did not generate detectable intracellular calcium or cAMP signals or show apparent receptor redistribution with moderate acid (pH ≥ 6.0) stimulation but reduced cAMP accumulation under strong acid stimulation (pH ≤ 5.5). Surprisingly, coexpression of OGR1- and G2A-enhanced proton sensitivity and proton-induced calcium signals. This alteration is attributed to oligomerization of OGR1 and G2A. The oligomeric potential locates receptors at a specific site, which leads to enhanced proton-induced calcium signals through channels.
Collapse
Affiliation(s)
- Ya-Han Huang
- a Department of Life Sciences , National Central University , Jhongli , Taiwan and
| | - Yeu-Shiuan Su
- a Department of Life Sciences , National Central University , Jhongli , Taiwan and
| | - Chung-Jen Chang
- a Department of Life Sciences , National Central University , Jhongli , Taiwan and
| | - Wei-Hsin Sun
- a Department of Life Sciences , National Central University , Jhongli , Taiwan and.,b Center for Biotechnology and Biomedical Engineering, National Central University , Jhongli , Taiwan
| |
Collapse
|
59
|
Franco R, Martínez-Pinilla E, Lanciego JL, Navarro G. Basic Pharmacological and Structural Evidence for Class A G-Protein-Coupled Receptor Heteromerization. Front Pharmacol 2016; 7:76. [PMID: 27065866 PMCID: PMC4815248 DOI: 10.3389/fphar.2016.00076] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 03/11/2016] [Indexed: 12/25/2022] Open
Abstract
Cell membrane receptors rarely work on isolation, often they form oligomeric complexes with other receptor molecules and they may directly interact with different proteins of the signal transduction machinery. For a variety of reasons, rhodopsin-like class A G-protein-coupled receptors (GPCRs) seem an exception to the general rule of receptor-receptor direct interaction. In fact, controversy surrounds their potential to form homo- hetero-dimers/oligomers with other class A GPCRs; in a sense, the field is going backward instead of forward. This review focuses on the convergent, complementary and telling evidence showing that homo- and heteromers of class A GPCRs exist in transfected cells and, more importantly, in natural sources. It is time to decide between questioning the occurrence of heteromers or, alternatively, facing the vast scientific and technical challenges that class A receptor-dimer/oligomer existence pose to Pharmacology and to Drug Discovery.
Collapse
Affiliation(s)
- Rafael Franco
- Departament de Bioquímica i Biomedicina Molecular, Facultat de Biología, Universitat de BarcelonaBarcelona, Spain; Centro de Investigación Biomédica en Red: Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos IIIMadrid, Spain; Institute of Biomedicine, University of BarcelonaBarcelona, Spain
| | - Eva Martínez-Pinilla
- Instituto de Neurociencias del Principado de Asturias, Departamento de Morfología y Biología Celular, Facultad de Medicina, Universidad de OviedoAsturias, Spain; Neurosciences Division, Centre for Applied Medical Research, University of NavarraPamplona, Spain; Instituto de Investigaciones Sanitarias de NavarraPamplona, Spain
| | - José L Lanciego
- Centro de Investigación Biomédica en Red: Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos IIIMadrid, Spain; Neurosciences Division, Centre for Applied Medical Research, University of NavarraPamplona, Spain; Instituto de Investigaciones Sanitarias de NavarraPamplona, Spain
| | - Gemma Navarro
- Departament de Bioquímica i Biomedicina Molecular, Facultat de Biología, Universitat de BarcelonaBarcelona, Spain; Centro de Investigación Biomédica en Red: Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos IIIMadrid, Spain
| |
Collapse
|
60
|
Neuroprotective mechanisms of the ACE2-angiotensin-(1-7)-Mas axis in stroke. Curr Hypertens Rep 2016; 17:3. [PMID: 25620630 DOI: 10.1007/s11906-014-0512-2] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The discovery of beneficial neuroprotective effects of the angiotensin converting enzyme 2-angiotensin-(1-7)-Mas axis [ACE2-Ang-(1-7)-Mas] in ischemic and hemorrhagic stroke has spurred interest in a more complete characterization of its mechanisms of action. Here, we summarize findings that describe the protective role of the ACE2-Ang-(1-7)-Mas axis in stroke, along with a focused discussion on the potential mechanisms of neuroprotective effects of Ang-(1-7) in stroke. The latter incorporates evidence describing the actions of Ang-(1-7) to counter the deleterious effects of angiotensin II (AngII) via its type 1 receptor, including anti-inflammatory, anti-oxidant, vasodilatory, and angiogenic effects, and the role of altered kinase-phosphatase signaling. Interactions of Mas with other receptors, including bradykinin receptors and AngII type 2 receptors are also considered. A more complete understanding of the mechanisms of action of Ang-(1-7) to elicit neuroprotection will serve as an essential step toward research into potential targeted therapeutics in the clinical setting.
Collapse
|
61
|
Molecular switches of the κ opioid receptor triggered by 6'-GNTI and 5'-GNTI. Sci Rep 2016; 6:18913. [PMID: 26742690 PMCID: PMC4705513 DOI: 10.1038/srep18913] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 11/30/2015] [Indexed: 12/29/2022] Open
Abstract
The κ opioid receptor (κOR) is a member of G-protein-coupled receptors, and is considered as a promising drug target for treating neurological diseases. κOR selective 6'-GNTI was proved to be a G-protein biased agonist, whereas 5'-GNTI acts as an antagonist. To investigate the molecular mechanism of how these two ligands induce different behaviors of the receptor, we built two systems containing the 5'-GNTI-κOR complex and the 6'-GNTI-κOR complex, respectively, and performed molecular dynamics simulations of the two systems. We observe that transmembrane (TM) helix 6 of the κOR rotates about 4.6(o) on average in the κOR-6'-GNTI complex. Detailed analyses of the simulation results indicate that E297(6.58) and I294(6.55) play crucial roles in the rotation of TM6. In the simulation of the κOR-5'-GNTI system, it is revealed that 5'-GNTI can stabilize TM6 in the inactive state form. In addition, the kink of TM7 is stabilized by a hydrogen bond between S324(7.47) and the residue V69(1.42) on TM1.
Collapse
|
62
|
Allosteric Modulators of the Class A G Protein Coupled Receptors. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 917:185-207. [PMID: 27236557 DOI: 10.1007/978-3-319-32805-8_9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Allosteric modulation is the regulation of a protein by binding of an effector molecule at the proteins allosteric site (a site other than that of the endogenous ligand). Allosteric modulators, by virtue of the fact that they may stabilize different global conformations of a receptor, have the potential to disrupt protein-protein interactions of very large proteins and elicit diverse functional responses. The existence of ligands that allosterically modulate the G protein receptor (GPCR) functions provides both challenges and opportunities for drug development campaigns. A number of therapeutic advantages of allosteric modulators over classic orthosteric ligands were proposed, involving nature of response, improved selectivity and ligand-directed signaling. In this review I discuss various aspects of allosteric modulation of GPCRs, which arise from the interactions of receptors with synthetic or endogenous small molecules, ions, lipids and diverse proteins. Detection and quantification of allosteric modulation will be also addressed. In the conclusion I will present future opportunities and challenges in the development of allosteric modulators as therapeutics.
Collapse
|
63
|
Abstract
Since their discovery, G protein-coupled receptors (GPCRs) constitute one of the most studied proteins leading to important discoveries and perspectives in terms of their biology and implication in physiology and pathophysiology. This is mostly linked to the remarkable advances in the development and application of the biophysical resonance energy transfer (RET)-based approaches, including bioluminescence and fluorescence resonance energy transfer (BRET and FRET, respectively). Indeed, BRET and FRET have been extensively applied to study different aspects of GPCR functioning such as their activation and regulation either statically or dynamically, in real-time and intact cells. Consequently, our view on GPCRs has considerably changed opening new challenges for the study of GPCRs in their native tissues in the aim to get more knowledge on how these receptors control the biological responses. Moreover, the technological aspect of this field of research promises further developments for robust and reliable new RET-based assays that may be compatible with high-throughput screening as well as drug discovery programs.
Collapse
Affiliation(s)
- Mohammed Akli Ayoub
- Biologie et Bioinformatique des Systèmes de Signalisation, Institut National de la Recherche Agronomique, UMR85, Unité Physiologie de la Reproduction et des Comportements; CNRS, UMR7247, Nouzilly, France; LE STUDIUM(®) Loire Valley Institute for Advanced Studies, Orléans, France.
| |
Collapse
|
64
|
Ganay T, Asraf H, Aizenman E, Bogdanovic M, Sekler I, Hershfinkel M. Regulation of neuronal pH by the metabotropic Zn(2+)-sensing Gq-coupled receptor, mZnR/GPR39. J Neurochem 2015; 135:897-907. [PMID: 26375174 DOI: 10.1111/jnc.13367] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2015] [Revised: 09/01/2015] [Accepted: 09/08/2015] [Indexed: 11/29/2022]
Abstract
Synaptically released Zn(2+) acts as a neurotransmitter, in part, by activating the postsynaptic metabotropic Zn(2+)-sensing Gq protein-coupled receptor (mZnR/GPR39). In previous work using epithelial cells, we described crosstalk between Zn(2+) signaling and changes in intracellular pH and/or extracellular pH (pHe). As pH changes accompany neuronal activity under physiological and pathological conditions, we tested whether Zn(2+) signaling is involved in regulation of neuronal pH. Here, we report that up-regulation of a major H(+) extrusion pathway, the Na(+)/H(+) exchanger (NHE), is induced by mZnR/GPR39 activation in an extracellular-regulated kinase 1/2-dependent manner in hippocampal neurons in vitro. We also observed that changes in pHe can modulate neuronal mZnR/GPR39-dependent signaling, resulting in reduced activity at pHe 8 or 6.5. Similarly, Zn(2+)-dependent extracellular-regulated kinase 1/2 phosphorylation and up-regulation of NHE activity were absent at acidic pHe. Thus, our results suggest that when pHe is maintained within the physiological range, mZnR/GPR39 activation can up-regulate NHE-dependent recovery from intracellular acidification. During acidosis, as pHe drops, mZnR/GPR39-dependent NHE activation is inhibited, thereby attenuating further H(+) extrusion. This mechanism may serve to protect neurons from excessive decreases in pHe. Thus, mZnR/GPR39 signaling provides a homeostatic adaptive process for regulation of intracellular and extracellular pH changes in the brain. We show that the postsynaptic metabotropic Zn(2+)-sensing Gq protein-coupled receptor (mZnR/GPR39) activation induces up-regulation of a major neuronal H(+) extrusion pathway, the Na(+)/H(+) exchanger (NHE), thereby enhancing neuronal recovery from intracellular acidification. Changes in extracellular pH (pHe), however, modulate neuronal mZnR/GPR39-dependent signaling, resulting in reduced activity at pHe 8 or 6.5. This mechanism may serve to protect neurons from excessive decreases in pHe during acidosis. Hence, mZnR/GPR39 signaling provides a homeostatic adaptive process for regulation of intracellular and extracellular pH changes in the brain.
Collapse
Affiliation(s)
- Thibault Ganay
- Department of Physiology and Cell Biology and The Zlotowski Center of Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Hila Asraf
- Department of Physiology and Cell Biology and The Zlotowski Center of Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Elias Aizenman
- Department of Physiology and Cell Biology and The Zlotowski Center of Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.,Department of Neurobiology and Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Milos Bogdanovic
- Department of Physiology and Cell Biology and The Zlotowski Center of Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Israel Sekler
- Department of Physiology and Cell Biology and The Zlotowski Center of Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Michal Hershfinkel
- Department of Physiology and Cell Biology and The Zlotowski Center of Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| |
Collapse
|
65
|
Devillier P, Naline E, Grassin-Delyle S. The pharmacology of bitter taste receptors and their role in human airways. Pharmacol Ther 2015; 155:11-21. [PMID: 26272040 DOI: 10.1016/j.pharmthera.2015.08.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The receptors involved in bitter taste perception (bitter taste receptors--T2Rs) constitute a family of G-protein-coupled receptors, of which around 29 subtypes have been identified in humans. T2R expression was initially thought to be confined to the oral cavity but has recently been described in a range of other tissues (such as the heart, gut, nasal cavity and lungs) and cell types (chemosensory, smooth muscle, endothelial, epithelial and inflammatory cells). Although it is still not clear whether endogenous T2R agonists exist, the T2R receptors recognize many natural and synthetic compounds, such as the acyl-homoserine lactones produced by bacteria, caffeine, chloroquine, and erythromycin. In the upper airways, T2Rs are involved in neurogenic inflammation and bacterial clearance. Their known effects in the lungs are exerted at three different levels. Firstly, T2R agonists increase the beating frequency of cilia on epithelial cells. Secondly, the T2Rs induce bronchial smooth muscle cells to relax. Thirdly, the T2R receptors expressed on immune cells (such as macrophages and mast cells) modulate production of pro-inflammatory mediators. Furthermore, T2R agonists are effective in inhibiting lung inflammation or smooth muscle contraction in ex vivo and asthma animal models, and are known to be involved in bacterial killing in the nasal cavity and enhancing lung function in humans. This review focuses on the pharmacology and physiological functions of T2R receptors in the upper and lower airways. It presents recently acquired knowledge suggesting that T2Rs may become valuable drug targets in the treatment of diseases such as asthma and chronic rhinosinusitis.
Collapse
Affiliation(s)
- Philippe Devillier
- Laboratoire de Pharmacologie, UPRES EA220, Hôpital Foch, 11 rue Guillaume Lenoir, 92150 Suresnes, France; Université Versailles Saint Quentin en Yvelines, UFR Sciences de la Santé, 2 avenue de la source de la Bièvre, 78180 Montigny-le-Bretonneux, France
| | - Emmanuel Naline
- Laboratoire de Pharmacologie, UPRES EA220, Hôpital Foch, 11 rue Guillaume Lenoir, 92150 Suresnes, France; Université Versailles Saint Quentin en Yvelines, UFR Sciences de la Santé, 2 avenue de la source de la Bièvre, 78180 Montigny-le-Bretonneux, France
| | - Stanislas Grassin-Delyle
- Laboratoire de Pharmacologie, UPRES EA220, Hôpital Foch, 11 rue Guillaume Lenoir, 92150 Suresnes, France; Université Versailles Saint Quentin en Yvelines, UFR Sciences de la Santé, 2 avenue de la source de la Bièvre, 78180 Montigny-le-Bretonneux, France.
| |
Collapse
|
66
|
Abstract
The angiotensin type 2 receptor (AT2R) and the receptor Mas are components of the protective arms of the renin-angiotensin system (RAS), i.e. they both mediate tissue protective and regenerative actions. The spectrum of actions of these two receptors and their signalling mechanisms display striking similarities. Moreover, in some instances, antagonists for one receptor are able to inhibit the action of agonists for the respective other receptor. These observations suggest that there may be a functional or even physical interaction of both receptors. This article discusses potential mechanisms underlying the phenomenon of blockade of angiotensin-(1-7) [Ang-(1-7)] actions by AT2R antagonists and vice versa. Such mechanisms may comprise dimerization of the receptors or dimerization-independent mechanisms such as lack of specificity of the receptor ligands used in the experiments or involvement of the Ang-(1-7) metabolite alamandine and its receptor MrgD in the observed effects. We conclude that evidence for a functional interaction of both receptors is strong, but that such an interaction may be species- and/or tissue-specific and that elucidation of the precise nature of the interaction is only at the very beginning.
Collapse
|
67
|
Dogra S, Yadav PN. Biased agonism at kappa opioid receptors: Implication in pain and mood disorders. Eur J Pharmacol 2015; 763:184-90. [PMID: 26164787 DOI: 10.1016/j.ejphar.2015.07.018] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 06/18/2015] [Accepted: 07/07/2015] [Indexed: 10/23/2022]
Abstract
The kappa opioid receptor (k receptor) and its endogenous ligand dynorphin have received significant attention due to their involvement in pathophysiology of mood disorders, drug addiction, psychotic disorders and pain. Multiple lines of evidences suggest that the k receptor modulates overlapping neurocircuits connecting brainstem monoaminergic nuclei with forebrain limbic structures and thereby regulates neurobiological effects of stress and psychostimulants. The emerging concept of "biased agonism" (also known as functional selectivity) for G Protein Coupled Receptor (GPCR) ligands have provided new insights into overall response generated by a ligand, which could be exploited for drug discovery. According to this concept, every ligand possesses the unique ability (coded in its structure) that dictates distinct signalling pattern, and consequently beneficial or adverse response. Although still a long way to comprehend the clinical potential of biased GPCR ligands, such ligand could be vital pharmacological probes. This article highlights various lines of evidence, which indicates different ligands of k receptor as "biased", and their potential implications in mood and pain disorders.
Collapse
Affiliation(s)
- Shalini Dogra
- Division of Pharmacology, CSIR-Central Drug Research Institute, Lucknow, UP 226031, India
| | - Prem N Yadav
- Division of Pharmacology, CSIR-Central Drug Research Institute, Lucknow, UP 226031, India.
| |
Collapse
|
68
|
Fujita W, Gomes I, Devi LA. Revolution in GPCR signalling: opioid receptor heteromers as novel therapeutic targets: IUPHAR review 10. Br J Pharmacol 2015; 171:4155-76. [PMID: 24916280 DOI: 10.1111/bph.12798] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 01/27/2014] [Accepted: 04/16/2014] [Indexed: 12/24/2022] Open
Abstract
GPCRs can interact with each other to form homomers or heteromers. Homomers involve interactions with the same receptor type while heteromers involve interactions between two different GPCRs. These receptor-receptor interactions modulate not only the binding but also the signalling and trafficking properties of individual receptors. Opioid receptor heteromerization has been extensively investigated with the objective of identifying novel therapeutic targets that are as potent as morphine but without the side effects associated with chronic morphine use. In this context, studies have described heteromerization between the different types of opioid receptors and between opioid receptors and a wide range of GPCRs including adrenoceptors, cannabinoid, 5-HT, metabotropic glutamate and sensory neuron-specific receptors. Recent advances in the field involving the generation of heteromer-specific reagents (antibodies or ligands) or of membrane-permeable peptides that disrupt the heteromer interaction are helping to elucidate the physiological role of opioid receptor heteromers and the contribution of the partner receptor to the side effects associated with opioid use. For example, studies using membrane-permeable peptides targeting the heteromer interface have implicated μ and δ receptor heteromers in the development of tolerance to morphine, and heteromers of μ and gastrin-releasing peptide receptors in morphine-induced itch. In addition, a number of ligands that selectively target opioid receptor heteromers exhibit potent antinociception with a decrease in the side effects commonly associated with morphine use. In this review, we summarize the latest findings regarding the biological and functional characteristics of opioid receptor heteromers both in vitro and in vivo.
Collapse
Affiliation(s)
- Wakako Fujita
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | | | | |
Collapse
|
69
|
Provasi D, Boz MB, Johnston JM, Filizola M. Preferred supramolecular organization and dimer interfaces of opioid receptors from simulated self-association. PLoS Comput Biol 2015; 11:e1004148. [PMID: 25822938 PMCID: PMC4379167 DOI: 10.1371/journal.pcbi.1004148] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 01/22/2015] [Indexed: 11/18/2022] Open
Abstract
Substantial evidence in support of the formation of opioid receptor (OR) di-/oligomers suggests previously unknown mechanisms used by these proteins to exert their biological functions. In an attempt to guide experimental assessment of the identity of the minimal signaling unit for ORs, we conducted extensive coarse-grained (CG) molecular dynamics (MD) simulations of different combinations of the three major OR subtypes, i.e., μ-OR, δ-OR, and κ-OR, in an explicit lipid bilayer. Specifically, we ran multiple, independent MD simulations of each homomeric μ-OR/μ-OR, δ-OR/δ-OR, and κ-OR/κ-OR complex, as well as two of the most studied heteromeric complexes, i.e., δ-OR/μ-OR and δ-OR/κ-OR, to derive the preferred supramolecular organization and dimer interfaces of ORs in a cell membrane model. These simulations yielded over 250 microseconds of accumulated data, which correspond to approximately 1 millisecond of effective simulated dynamics according to established scaling factors of the CG model we employed. Analysis of these data indicates similar preferred supramolecular organization and dimer interfaces of ORs across the different receptor subtypes, but also important differences in the kinetics of receptor association at specific dimer interfaces. We also investigated the kinetic properties of interfacial lipids, and explored their possible role in modulating the rate of receptor association and in promoting the formation of filiform aggregates, thus supporting a distinctive role of the membrane in OR oligomerization and, possibly, signaling.
Collapse
Affiliation(s)
- Davide Provasi
- Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
| | - Mustafa Burak Boz
- Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
| | - Jennifer M. Johnston
- Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
| | - Marta Filizola
- Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
- * E-mail:
| |
Collapse
|
70
|
|
71
|
Mudgal A, Pasha S. Role of opioid receptor heterodimerization in pain modulation and tolerance development. World J Pharmacol 2015; 4:144-159. [DOI: 10.5497/wjp.v4.i1.144] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 10/09/2014] [Accepted: 02/11/2015] [Indexed: 02/06/2023] Open
Abstract
Protein to protein interactions leading to homo/heteromerization of receptor is well documented in literature. These interactions leading to dimeric/oligomers formation of receptors are known to modulate their function, particularly in case of G-protein coupled receptors. The opioid receptor heteromers having changed pharmacological properties than the constituent protomers provides preferences for novel drug targets that could lead to potential analgesic activity devoid of tolerance and physical dependence. Heterodimerization of opioid receptors appears to generate novel binding properties with improved specificity and lack of side effects. Further the molecules which can interact simultaneously to both the protomers of the heteromer, or to both the binding sites (orthosteric and allosteric) of a receptor protein could be potential therapeutic molecules. This review highlights the recent advancements in exploring the plausible role of heteromerization of opioid receptors in induction of tolerance free antinociception.
Collapse
|
72
|
Bellot M, Galandrin S, Boularan C, Matthies HJ, Despas F, Denis C, Javitch J, Mazères S, Sanni SJ, Pons V, Seguelas MH, Hansen JL, Pathak A, Galli A, Sénard JM, Galés C. Dual agonist occupancy of AT1-R-α2C-AR heterodimers results in atypical Gs-PKA signaling. Nat Chem Biol 2015; 11:271-9. [PMID: 25706338 DOI: 10.1038/nchembio.1766] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 01/09/2015] [Indexed: 12/25/2022]
Abstract
Hypersecretion of norepinephrine (NE) and angiotensin II (AngII) is a hallmark of major prevalent cardiovascular diseases that contribute to cardiac pathophysiology and morbidity. Herein, we explore whether heterodimerization of presynaptic AngII AT1 receptor (AT1-R) and NE α2C-adrenergic receptor (α2C-AR) could underlie their functional cross-talk to control NE secretion. Multiple bioluminescence resonance energy transfer and protein complementation assays allowed us to accurately probe the structures and functions of the α2C-AR-AT1-R dimer promoted by ligand binding to individual protomers. We found that dual agonist occupancy resulted in a conformation of the heterodimer different from that induced by active individual protomers and triggered atypical Gs-cAMP-PKA signaling. This specific pharmacological signaling unit was identified in vivo to promote not only NE hypersecretion in sympathetic neurons but also sympathetic hyperactivity in mice. Thus, we uncovered a new process by which GPCR heterodimerization creates an original functional pharmacological entity and that could constitute a promising new target in cardiovascular therapeutics.
Collapse
Affiliation(s)
- Morgane Bellot
- Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, U1048, Université Toulouse III Paul Sabatier, Toulouse, France
| | - Ségolène Galandrin
- Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, U1048, Université Toulouse III Paul Sabatier, Toulouse, France
| | - Cédric Boularan
- Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, U1048, Université Toulouse III Paul Sabatier, Toulouse, France
| | - Heinrich J Matthies
- 1] Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA. [2] Neuroscience Program in Substance Abuse, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Fabien Despas
- 1] Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, U1048, Université Toulouse III Paul Sabatier, Toulouse, France. [2] Service de Pharmacologie Clinique, Centre Hospitalier Universitaire de Toulouse, Faculté de Médecine, Toulouse, France
| | - Colette Denis
- Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, U1048, Université Toulouse III Paul Sabatier, Toulouse, France
| | - Jonathan Javitch
- 1] Center for Molecular Recognition and Departments of Psychiatry and Pharmacology, Columbia University, New York, New York, USA. [2] College of Physicians and Surgeons, Columbia University, New York, New York, USA. [3] Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, New York, USA
| | - Serge Mazères
- Institut de Pharmacologie et de Biologie Structurale (IPBS), CNRS, UMR 508, Université Toulouse III Paul Sabatier, Toulouse, France
| | - Samra Joke Sanni
- 1] Department of Clinical Biochemistry, Glostrup Hospital, Glostrup, Denmark. [2] Diabetes Biology and Metabolism, Novo Nordisk, Måløv, Denmark
| | - Véronique Pons
- Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, U1048, Université Toulouse III Paul Sabatier, Toulouse, France
| | - Marie-Hélène Seguelas
- Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, U1048, Université Toulouse III Paul Sabatier, Toulouse, France
| | - Jakob L Hansen
- Diabetes Biology and Metabolism, Novo Nordisk, Måløv, Denmark
| | - Atul Pathak
- 1] Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, U1048, Université Toulouse III Paul Sabatier, Toulouse, France. [2] Service de Pharmacologie Clinique, Centre Hospitalier Universitaire de Toulouse, Faculté de Médecine, Toulouse, France
| | - Aurelio Galli
- 1] Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA. [2] Neuroscience Program in Substance Abuse, Vanderbilt University School of Medicine, Nashville, Tennessee, USA. [3] Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, Tennessee, USA. [4] Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Jean-Michel Sénard
- 1] Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, U1048, Université Toulouse III Paul Sabatier, Toulouse, France. [2] Service de Pharmacologie Clinique, Centre Hospitalier Universitaire de Toulouse, Faculté de Médecine, Toulouse, France
| | - Céline Galés
- Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, U1048, Université Toulouse III Paul Sabatier, Toulouse, France
| |
Collapse
|
73
|
Naumenko VS, Popova NK, Lacivita E, Leopoldo M, Ponimaskin EG. Interplay between serotonin 5-HT1A and 5-HT7 receptors in depressive disorders. CNS Neurosci Ther 2015; 20:582-90. [PMID: 24935787 DOI: 10.1111/cns.12247] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Revised: 02/11/2014] [Accepted: 02/12/2014] [Indexed: 11/26/2022] Open
Abstract
Serotonin (5-hydroxytryptamine or 5-HT) is an important neurotransmitter regulating a wide range of physiological and pathological functions via activation of heterogeneously expressed 5-HT receptors. Besides the important role of 5-HT receptors in the pathogenesis of depressive disorders and in their clinical medications, underlying mechanisms are far from being completely understood. This review focuses on possible cross talk between two serotonin receptors, 5-HT1A and the 5-HT7 . Although these receptors are highly co-expressed in brain regions implicated in depression, and most agonists developed for the 5-HT1A or 5-HT7 receptors have cross-reactivity, their functional interaction has not been yet established. It has been recently shown that 5-HT1A and 5-HT7 receptors form homo- and heterodimers both in vitro and in vivo. From the functional point of view, heterodimerization has been shown to play an important role in regulation of receptor-mediated signaling and internalization, suggesting the implication of heterodimerization in the development and maintenance of depression. Interaction between these receptors is also of clinical interest, because both receptors represent an important pharmacological target for the treatment of depression and anxiety.
Collapse
Affiliation(s)
- Vladimir S Naumenko
- Department of Behavioral Neurogenomics, Institute of Cytology and Genetics, Novosibirsk, Russia
| | | | | | | | | |
Collapse
|
74
|
Konoura K, Fujii H, Imaide S, Gouda H, Hirayama S, Hirono S, Nagase H. Transformation of naltrexone into mesembrane and investigation of the binding properties of its intermediate derivatives to opioid receptors. Bioorg Med Chem 2015; 23:439-48. [DOI: 10.1016/j.bmc.2014.12.032] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 12/15/2014] [Accepted: 12/15/2014] [Indexed: 11/28/2022]
|
75
|
Kilpatrick LE, Humphrys LJ, Holliday ND. A G protein-coupled receptor dimer imaging assay reveals selectively modified pharmacology of neuropeptide Y Y1/Y5 receptor heterodimers. Mol Pharmacol 2015; 87:718-32. [PMID: 25637604 DOI: 10.1124/mol.114.095356] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The ability of G protein-coupled receptors (GPCRs) to form dimers, and particularly heterodimers, offers potential for targeted therapeutics with improved selectivity. However, studying dimer pharmacology is challenging, because of signaling cross-talk or because dimerization may often be transient in nature. Here we develop a system to isolate the pharmacology of precisely defined GPCR dimers, trapped by bimolecular fluorescence complementation (BiFC). Specific effects of agonist activation on such dimers are quantified using automated imaging and analysis of their internalization, controlled for by simultaneous assessment of endocytosis of one coexpressed protomer population. We applied this BiFC system to study example neuropeptide Y (NPY) Y1 receptor dimers. Incorporation of binding-site or phosphorylation-site mutations into just one protomer of a Y1/Y1 BiFC homodimer had no impact on efficient NPY-stimulated endocytosis, demonstrating that single-site agonist occupancy, and one phosphorylated monomer within this dimer, was sufficient. For two Y1 receptor heterodimer combinations (with the Y4 receptor or β2-adrenoceptor), agonist and antagonist pharmacology was explained by independent actions on the respective orthosteric binding sites. However, Y1/Y5 receptor BiFC dimers, compared with the constituent subtypes, were characterized by reduced potency and efficacy of Y5-selective peptide agonists, the inactivity of Y1-selective antagonists, and a change from surmountable to nonsurmountable antagonism for three unrelated Y5 antagonists. Thus, allosteric interactions between Y1 and Y5 receptors modify the pharmacology of the heterodimer, with implications for potential antiobesity agents that target centrally coexpressed Y1 and Y5 receptors to suppress appetite.
Collapse
Affiliation(s)
- Laura E Kilpatrick
- School of Life Sciences, University of Nottingham, The Medical School, Queen's Medical Centre, Nottingham, United Kingdom
| | - Laura J Humphrys
- School of Life Sciences, University of Nottingham, The Medical School, Queen's Medical Centre, Nottingham, United Kingdom
| | - Nicholas D Holliday
- School of Life Sciences, University of Nottingham, The Medical School, Queen's Medical Centre, Nottingham, United Kingdom
| |
Collapse
|
76
|
Herrick-Davis K, Grinde E, Lindsley T, Teitler M, Mancia F, Cowan A, Mazurkiewicz JE. Native serotonin 5-HT2C receptors are expressed as homodimers on the apical surface of choroid plexus epithelial cells. Mol Pharmacol 2015; 87:660-73. [PMID: 25609374 DOI: 10.1124/mol.114.096636] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
G protein-coupled receptors (GPCRs) are a prominent class of plasma membrane proteins that regulate physiologic responses to a wide variety of stimuli and therapeutic agents. Although GPCR oligomerization has been studied extensively in recombinant cells, it remains uncertain whether native receptors expressed in their natural cellular environment are monomers, dimers, or oligomers. The goal of this study was to determine the monomer/oligomer status of a native GPCR endogenously expressed in its natural cellular environment. Native 5-HT2C receptors in choroid plexus epithelial cells were evaluated using fluorescence correlation spectroscopy (FCS) with photon counting histogram (PCH). An anti-5-HT2C fragment antigen binding protein was used to label native 5-HT2C receptors. A known monomeric receptor (CD-86) served as a control for decoding the oligomer status of native 5-HT2C receptors by molecular brightness analysis. FCS with PCH revealed molecular brightness values for native 5-HT2C receptors equivalent to the molecular brightness of a homodimer. 5-HT2C receptors displayed a diffusion coefficient of 5 × 10(-9) cm(2)/s and were expressed at 32 receptors/μm(2) on the apical surface of choroid plexus epithelial cells. The functional significance and signaling capabilities of the homodimer were investigated in human embryonic kidney 293 cells using agonists that bind in a wash-resistant manner to one or both protomers of the homodimer. Whereas agonist binding to one protomer resulted in G protein activation, maximal stimulation required occupancy of both protomers. This study is the first to demonstrate the homodimeric structure of 5-HT2C receptors endogenously expressed in their native cellular environment, and identifies the homodimer as a functional signaling unit.
Collapse
Affiliation(s)
- Katharine Herrick-Davis
- Center for Neuropharmacology & Neuroscience, Albany Medical College, Albany, New York (K.H.-D., E.G., T.L., M.T., J.E.M.); Department of Physiology and Cellular Biophysics, Columbia University, New York, New York (F.M.); and Center for Cell Analysis and Modeling, University of Connecticut Health Center, Farmington, Connecticut (A.C.)
| | - Ellinor Grinde
- Center for Neuropharmacology & Neuroscience, Albany Medical College, Albany, New York (K.H.-D., E.G., T.L., M.T., J.E.M.); Department of Physiology and Cellular Biophysics, Columbia University, New York, New York (F.M.); and Center for Cell Analysis and Modeling, University of Connecticut Health Center, Farmington, Connecticut (A.C.)
| | - Tara Lindsley
- Center for Neuropharmacology & Neuroscience, Albany Medical College, Albany, New York (K.H.-D., E.G., T.L., M.T., J.E.M.); Department of Physiology and Cellular Biophysics, Columbia University, New York, New York (F.M.); and Center for Cell Analysis and Modeling, University of Connecticut Health Center, Farmington, Connecticut (A.C.)
| | - Milt Teitler
- Center for Neuropharmacology & Neuroscience, Albany Medical College, Albany, New York (K.H.-D., E.G., T.L., M.T., J.E.M.); Department of Physiology and Cellular Biophysics, Columbia University, New York, New York (F.M.); and Center for Cell Analysis and Modeling, University of Connecticut Health Center, Farmington, Connecticut (A.C.)
| | - Filippo Mancia
- Center for Neuropharmacology & Neuroscience, Albany Medical College, Albany, New York (K.H.-D., E.G., T.L., M.T., J.E.M.); Department of Physiology and Cellular Biophysics, Columbia University, New York, New York (F.M.); and Center for Cell Analysis and Modeling, University of Connecticut Health Center, Farmington, Connecticut (A.C.)
| | - Ann Cowan
- Center for Neuropharmacology & Neuroscience, Albany Medical College, Albany, New York (K.H.-D., E.G., T.L., M.T., J.E.M.); Department of Physiology and Cellular Biophysics, Columbia University, New York, New York (F.M.); and Center for Cell Analysis and Modeling, University of Connecticut Health Center, Farmington, Connecticut (A.C.)
| | - Joseph E Mazurkiewicz
- Center for Neuropharmacology & Neuroscience, Albany Medical College, Albany, New York (K.H.-D., E.G., T.L., M.T., J.E.M.); Department of Physiology and Cellular Biophysics, Columbia University, New York, New York (F.M.); and Center for Cell Analysis and Modeling, University of Connecticut Health Center, Farmington, Connecticut (A.C.)
| |
Collapse
|
77
|
Murphy NP. Dynamic measurement of extracellular opioid activity: status quo, challenges, and significance in rewarded behaviors. ACS Chem Neurosci 2015; 6:94-107. [PMID: 25585132 DOI: 10.1021/cn500295q] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Opioid peptides are the endogenous ligands of opioid receptors, which are also the molecular target of naturally occurring and synthetic opiates, such as morphine and heroin. Since their discovery in the 1970s, opioid peptides, which are found widely throughout the central nervous system and the periphery, have been intensely studied because of their involvement in pain and pleasure. Over the years, our understanding of opioid peptides has widened to cover a multitude of functions, including learning and memory, affective state, gastrointestinal transit, feeding, immune function, and metabolism. Unsurprisingly, aberrant opioid activity is implicated in numerous pathologies, including drug addiction, overeating, pain, depression, and obesity. To date, virtually all preclinical and clinical studies aimed at understanding the function of endogenous opioids have relied upon manipulating endogenous opioid fluxes using opioid receptor ligands or genetic manipulations of opioid receptors and endogenous opioids. Difficulties in directly monitoring endogenous opioid fluxes, particularly in the central nervous system, have presented a major obstacle to fully understanding endogenous opioid function. This review summarizes these challenges and offers suggestions for future goals while focusing on the neurobiology of reward, specifically drawing attention to studies that have succeeded in dynamically measuring opioid peptides.
Collapse
Affiliation(s)
- Niall P. Murphy
- Department of Psychiatry
and Biobehavioral Sciences, Univesity of California, Los Angeles, 2579 MacDonald
Research Laboratories, 675 Charles E. Young Drive
South Los Angeles, California 90095, United States
| |
Collapse
|
78
|
Gomes I, Gupta A, Bushlin I, Devi LA. Antibodies to probe endogenous G protein-coupled receptor heteromer expression, regulation, and function. Front Pharmacol 2014; 5:268. [PMID: 25520661 PMCID: PMC4253664 DOI: 10.3389/fphar.2014.00268] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 11/16/2014] [Indexed: 11/13/2022] Open
Abstract
Over the last decade an increasing number of studies have focused on the ability of G protein-coupled receptors to form heteromers and explored how receptor heteromerization modulates the binding, signaling and trafficking properties of individual receptors. Most of these studies were carried out in heterologous cells expressing epitope tagged receptors. Very little information is available about the in vivo physiological role of G protein-coupled receptor heteromers due to a lack of tools to detect their presence in endogenous tissue. Recent advances such as the generation of mouse models expressing fluorescently labeled receptors, of TAT based peptides that can disrupt a given heteromer pair, or of heteromer-selective antibodies that recognize the heteromer in endogenous tissue have begun to elucidate the physiological and pathological roles of receptor heteromers. In this review we have focused on heteromer-selective antibodies and describe how a subtractive immunization strategy can be successfully used to generate antibodies that selectively recognize a desired heteromer pair. We also describe the uses of these antibodies to detect the presence of heteromers, to study their properties in endogenous tissues, and to monitor changes in heteromer levels under pathological conditions. Together, these findings suggest that G protein-coupled receptor heteromers represent unique targets for the development of drugs with reduced side-effects.
Collapse
Affiliation(s)
- Ivone Gomes
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai New York, NY, USA
| | - Achla Gupta
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai New York, NY, USA
| | - Ittai Bushlin
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai New York, NY, USA
| | - Lakshmi A Devi
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai New York, NY, USA ; The Friedman Brain Institute, Icahn School of Medicine at Mount Sinai New York, NY, USA
| |
Collapse
|
79
|
Brogi S, Tafi A, Désaubry L, Nebigil CG. Discovery of GPCR ligands for probing signal transduction pathways. Front Pharmacol 2014; 5:255. [PMID: 25506327 PMCID: PMC4246677 DOI: 10.3389/fphar.2014.00255] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 11/02/2014] [Indexed: 01/11/2023] Open
Abstract
G protein-coupled receptors (GPCRs) are seven integral transmembrane proteins that are the primary targets of almost 30% of approved drugs and continue to represent a major focus of pharmaceutical research. All of GPCR targeted medicines were discovered by classical medicinal chemistry approaches. After the first GPCR crystal structures were determined, the docking screens using these structures lead to discovery of more novel and potent ligands. There are over 360 pharmaceutically relevant GPCRs in the human genome and to date about only 30 of structures have been determined. For these reasons, computational techniques such as homology modeling and molecular dynamics simulations have proven their usefulness to explore the structure and function of GPCRs. Furthermore, structure-based drug design and in silico screening (High Throughput Docking) are still the most common computational procedures in GPCRs drug discovery. Moreover, ligand-based methods such as three-dimensional quantitative structure–selectivity relationships, are the ideal molecular modeling approaches to rationalize the activity of tested GPCR ligands and identify novel GPCR ligands. In this review, we discuss the most recent advances for the computational approaches to effectively guide selectivity and affinity of ligands. We also describe novel approaches in medicinal chemistry, such as the development of biased agonists, allosteric modulators, and bivalent ligands for class A GPCRs. Furthermore, we highlight some knockout mice models in discovering biased signaling selectivity.
Collapse
Affiliation(s)
- Simone Brogi
- European Research Centre for Drug Discovery and Development (NatSynDrugs), University of Siena Siena, Italy ; Department of Biotechnology, Chemistry and Pharmacy, University of Siena Siena, Italy
| | - Andrea Tafi
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena Siena, Italy
| | - Laurent Désaubry
- Therapeutic Innovation Laboratory, UMR7200, CNRS/University of Strasbourg Illkirch, France
| | - Canan G Nebigil
- Receptor Signaling and Therapeutic Innovations, GPCR and Cardiovascular and Metabolic Regulations, Biotechnology and Cell Signaling Laboratory, UMR 7242, CNRS/University of Strasbourg - LabEx Medalis Illkirch, France
| |
Collapse
|
80
|
Thompson GL, Canals M, Poole DP. Biological redundancy of endogenous GPCR ligands in the gut and the potential for endogenous functional selectivity. Front Pharmacol 2014; 5:262. [PMID: 25506328 PMCID: PMC4246669 DOI: 10.3389/fphar.2014.00262] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 11/12/2014] [Indexed: 01/27/2023] Open
Abstract
This review focuses on the existence and function of multiple endogenous agonists of the somatostatin and opioid receptors with an emphasis on their expression in the gastrointestinal tract. These agonists generally arise from the proteolytic cleavage of prepropeptides during peptide maturation or from degradation of peptides by extracellular or intracellular endopeptidases. In other examples, endogenous peptide agonists for the same G protein-coupled receptors can be products of distinct genes but contain high sequence homology. This apparent biological redundancy has recently been challenged by the realization that different ligands may engender distinct receptor conformations linked to different intracellular signaling profiles and, as such the existence of distinct ligands may underlie mechanisms to finely tune physiological responses. We propose that further characterization of signaling pathways activated by these endogenous ligands will provide invaluable insight into the mechanisms governing biased agonism. Moreover, these ligands may prove useful in the design of novel therapeutic tools to target distinct signaling pathways, thereby favoring desirable effects and limiting detrimental on-target effects. Finally we will discuss the limitations of this area of research and we will highlight the difficulties that need to be addressed when examining endogenous bias in tissues and in animals.
Collapse
Affiliation(s)
- Georgina L Thompson
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences Parkville, VIC, Australia
| | - Meritxell Canals
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences Parkville, VIC, Australia
| | - Daniel P Poole
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences Parkville, VIC, Australia ; Department of Anatomy and Neuroscience, The University of Melbourne Parkville, VIC, Australia
| |
Collapse
|
81
|
Guidolin D, Agnati LF, Marcoli M, Borroto-Escuela DO, Fuxe K. G-protein-coupled receptor type A heteromers as an emerging therapeutic target. Expert Opin Ther Targets 2014; 19:265-83. [PMID: 25381716 DOI: 10.1517/14728222.2014.981155] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION The discovery of receptor-receptor interactions (RRIs) in the early 1980s provided evidence that G-protein-coupled receptors (GPCRs) operate not only as monomers but also as heteromers, in which integration of the incoming signals takes place already at the plasma membrane level through allosteric RRIs. These integrative mechanisms give sophisticated dynamics to the structure and function of these receptor assemblies in terms of modulation of recognition, G-protein signaling and selectivity and switching to β-arrestin signaling. AREAS COVERED The present review briefly describes the concept of direct RRI and the available data on the mechanisms of oligomer formation. Further, pharmacological data concerning the best characterized heteromers involving type A GPCRs will be analyzed to evaluate their profile as possible targets for the treatment of various diseases, in particular of impacting diseases of the CNS. EXPERT OPINION GPCR heteromers have the potential to open a completely new field for pharmacology with likely a major impact in molecular medicine. Novel pharmacological strategies for the treatment of several pathologies have already been proposed. However, several challenges still exist to accurately characterize the role of the identified heteroreceptor complexes in pathology and to develop heteromer-specific ligands capable of efficiently exploiting their pharmacological features.
Collapse
Affiliation(s)
- Diego Guidolin
- University of Padova, Department of Molecular Medicine , via Gabelli 65, 35121 Padova , Italy +39 049 8272316 ; +39 049 8272319 ;
| | | | | | | | | |
Collapse
|
82
|
Martínez-Pinilla E, Reyes-Resina I, Oñatibia-Astibia A, Zamarbide M, Ricobaraza A, Navarro G, Moreno E, Dopeso-Reyes I, Sierra S, Rico A, Roda E, Lanciego J, Franco R. CB1 and GPR55 receptors are co-expressed and form heteromers in rat and monkey striatum. Exp Neurol 2014; 261:44-52. [DOI: 10.1016/j.expneurol.2014.06.017] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 06/13/2014] [Accepted: 06/17/2014] [Indexed: 10/25/2022]
|
83
|
Szalai B, Hoffmann P, Prokop S, Erdélyi L, Várnai P, Hunyady L. Improved methodical approach for quantitative BRET analysis of G Protein Coupled Receptor dimerization. PLoS One 2014; 9:e109503. [PMID: 25329164 PMCID: PMC4201472 DOI: 10.1371/journal.pone.0109503] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 09/11/2014] [Indexed: 01/22/2023] Open
Abstract
G Protein Coupled Receptors (GPCR) can form dimers or higher ordered oligomers, the process of which can remarkably influence the physiological and pharmacological function of these receptors. Quantitative Bioluminescence Resonance Energy Transfer (qBRET) measurements are the gold standards to prove the direct physical interaction between the protomers of presumed GPCR dimers. For the correct interpretation of these experiments, the expression of the energy donor Renilla luciferase labeled receptor has to be maintained constant, which is hard to achieve in expression systems. To analyze the effects of non-constant donor expression on qBRET curves, we performed Monte Carlo simulations. Our results show that the decrease of donor expression can lead to saturation qBRET curves even if the interaction between donor and acceptor labeled receptors is non-specific leading to false interpretation of the dimerization state. We suggest here a new approach to the analysis of qBRET data, when the BRET ratio is plotted as a function of the acceptor labeled receptor expression at various donor receptor expression levels. With this method, we were able to distinguish between dimerization and non-specific interaction when the results of classical qBRET experiments were ambiguous. The simulation results were confirmed experimentally using rapamycin inducible heterodimerization system. We used this new method to investigate the dimerization of various GPCRs, and our data have confirmed the homodimerization of V2 vasopressin and CaSR calcium sensing receptors, whereas our data argue against the heterodimerization of these receptors with other studied GPCRs, including type I and II angiotensin, β2 adrenergic and CB1 cannabinoid receptors.
Collapse
Affiliation(s)
- Bence Szalai
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
- MTA-SE Laboratory of Molecular Physiology, Budapest, Hungary
| | - Péter Hoffmann
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Susanne Prokop
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - László Erdélyi
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
- MTA-SE Laboratory of Molecular Physiology, Budapest, Hungary
| | - Péter Várnai
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
- MTA-SE Laboratory of Molecular Physiology, Budapest, Hungary
| | - László Hunyady
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
- MTA-SE Laboratory of Molecular Physiology, Budapest, Hungary
- * E-mail:
| |
Collapse
|
84
|
Balenga NA, Martínez-Pinilla E, Kargl J, Schröder R, Peinhaupt M, Platzer W, Bálint Z, Zamarbide M, Dopeso-Reyes IG, Ricobaraza A, Pérez-Ortiz JM, Kostenis E, Waldhoer M, Heinemann A, Franco R. Heteromerization of GPR55 and cannabinoid CB2 receptors modulates signalling. Br J Pharmacol 2014; 171:5387-406. [PMID: 25048571 DOI: 10.1111/bph.12850] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2013] [Revised: 07/01/2014] [Accepted: 07/14/2014] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND AND PURPOSE Heteromerization of GPCRs is key to the integration of extracellular signals and the subsequent cell response via several mechanisms including heteromer-selective ligand binding, trafficking and/or downstream signalling. As the lysophosphatidylinositol GPCR 55 (GPR55) has been shown to affect the function of the cannabinoid receptor subtype 2 (CB2 receptor) in human neutrophils, we investigated the possible heteromerization of CB2 receptors with GPR55. EXPERIMENTAL APPROACH The direct interaction of human GPR55 and CB2 receptors heterologously expressed in HEK293 cells was assessed by co-immunoprecipitation and bioluminescence resonance energy transfer assays. The effect of cross-talk on signalling was investigated at downstream levels by label-free real-time methods (Epic dynamic mass redistribution and CellKey impedance assays), ERK1/2-MAPK activation and gene reporter assays. KEY RESULTS GPR55 and CB2 receptors co-localized on the surface of HEK293 cells, co-precipitated in membrane extracts and formed heteromers in living HEK293 cells. Whereas heteromerization led to a reduction in GPR55-mediated activation of transcription factors (nuclear factor of activated T-cells, NF-κB and cAMP response element), ERK1/2-MAPK activation was potentiated in the presence of CB2 receptors. CB2 receptor-mediated signalling was also affected by co-expression with GPR55. Label-free assays confirmed cross-talk between the two receptors. CONCLUSIONS AND IMPLICATIONS Heteromers, unique signalling units, form in HEK293 cells expressing GPR55 and CB2 receptors. The signalling by agonists of either receptor was governed (i) by the presence or absence of the partner receptors (with the consequent formation of heteromers) and (ii) by the activation state of the partner receptor.
Collapse
Affiliation(s)
- N A Balenga
- Institute for Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
85
|
Le Naour M, Lunzer MM, Powers MD, Kalyuzhny AE, Benneyworth MA, Thomas MJ, Portoghese PS. Putative kappa opioid heteromers as targets for developing analgesics free of adverse effects. J Med Chem 2014; 57:6383-92. [PMID: 24978316 PMCID: PMC4136663 DOI: 10.1021/jm500159d] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Indexed: 11/29/2022]
Abstract
It is now generally recognized that upon activation by an agonist, β-arrestin associates with G protein-coupled receptors and acts as a scaffold in creating a diverse signaling network that could lead to adverse effects. As an approach to reducing side effects associated with κ opioid agonists, a series of β-naltrexamides 3-10 was synthesized in an effort to selectively target putative κ opioid heteromers without recruiting β-arrestin upon activation. The most potent derivative 3 (INTA) strongly activated KOR-DOR and KOR-MOR heteromers in HEK293 cells. In vivo studies revealed 3 to produce potent antinociception, which, when taken together with antagonism data, was consistent with the activation of both heteromers. 3 was devoid of tolerance, dependence, and showed no aversive effect in the conditioned place preference assay. As immunofluorescence studies indicated no recruitment of β-arrestin2 to membranes in coexpressed KOR-DOR cells, this study suggests that targeting of specific putative heteromers has the potential to identify leads for analgesics devoid of adverse effects.
Collapse
MESH Headings
- Analgesics/adverse effects
- Analgesics/chemistry
- Analgesics/pharmacology
- Animals
- Arrestins/metabolism
- Avoidance Learning/drug effects
- Calcium/metabolism
- Drug Tolerance
- HEK293 Cells
- Humans
- Indoles/adverse effects
- Indoles/chemistry
- Indoles/pharmacology
- Mice
- Naltrexone/adverse effects
- Naltrexone/analogs & derivatives
- Naltrexone/chemistry
- Naltrexone/pharmacology
- Protein Multimerization
- Receptors, Opioid, delta/agonists
- Receptors, Opioid, delta/metabolism
- Receptors, Opioid, kappa/agonists
- Receptors, Opioid, kappa/metabolism
- Receptors, Opioid, mu/agonists
- Receptors, Opioid, mu/metabolism
- Stereoisomerism
- Structure-Activity Relationship
- Substance-Related Disorders/etiology
- beta-Arrestins
Collapse
Affiliation(s)
- Morgan Le Naour
- Department of Medicinal Chemistry, College of Pharmacy, University of Minnesota , WDH 8-114, 308 Harvard Street SE, Minneapolis, Minnesota 55455, United States
| | | | | | | | | | | | | |
Collapse
|
86
|
Burford NT, Wehrman T, Bassoni D, O'Connell J, Banks M, Zhang L, Alt A. Identification of selective agonists and positive allosteric modulators for µ- and δ-opioid receptors from a single high-throughput screen. ACTA ACUST UNITED AC 2014; 19:1255-65. [PMID: 25047277 DOI: 10.1177/1087057114542975] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Hetero-oligomeric complexes of G protein-coupled receptors (GPCRs) may represent novel therapeutic targets exhibiting different pharmacology and tissue- or cell-specific site of action compared with receptor monomers or homo-oligomers. An ideal tool for validating this concept pharmacologically would be a hetero-oligomer selective ligand. We set out to develop and execute a 1536-well high-throughput screen of over 1 million compounds to detect potential hetero-oligomer selective ligands using a β-arrestin recruitment assay in U2OS cells coexpressing recombinant µ- and δ-opioid receptors. Hetero-oligomer selective ligands may bind to orthosteric or allosteric sites, and we might anticipate that the formation of hetero-oligomers may provide novel allosteric binding pockets for ligand binding. Therefore, our goal was to execute the screen in such a way as to identify positive allosteric modulators (PAMs) as well as agonists for µ, δ, and hetero-oligomeric receptors. While no hetero-oligomer selective ligands were identified (based on our selection criteria), this single screen did identify numerous µ- and δ-selective agonists and PAMs as well as nonselective agonists and PAMs. To our knowledge, these are the first µ- and δ-opioid receptor PAMs described in the literature.
Collapse
Affiliation(s)
- Neil T Burford
- Leads Discovery and Optimization, Bristol-Myers Squibb Company, Wallingford, CT, USA
| | | | | | | | - Martyn Banks
- Leads Discovery and Optimization, Bristol-Myers Squibb Company, Wallingford, CT, USA
| | - Litao Zhang
- Leads Discovery and Optimization, Bristol-Myers Squibb Company, Wallingford, CT, USA
| | - Andrew Alt
- Leads Discovery and Optimization, Bristol-Myers Squibb Company, Wallingford, CT, USA
| |
Collapse
|
87
|
Nagi K, Pineyro G. Kir3 channel signaling complexes: focus on opioid receptor signaling. Front Cell Neurosci 2014; 8:186. [PMID: 25071446 PMCID: PMC4085882 DOI: 10.3389/fncel.2014.00186] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2014] [Accepted: 06/18/2014] [Indexed: 12/03/2022] Open
Abstract
Opioids are among the most effective drugs to treat severe pain. They produce their analgesic actions by specifically activating opioid receptors located along the pain perception pathway where they inhibit the flow of nociceptive information. This inhibition is partly accomplished by activation of hyperpolarizing G protein-coupled inwardly-rectifying potassium (GIRK or Kir3) channels. Kir3 channels control cellular excitability in the central nervous system and in the heart and, because of their ubiquitous distribution, they mediate the effects of a large range of hormones and neurotransmitters which, upon activation of corresponding G protein-coupled receptors (GPCRs) lead to channel opening. Here we analyze GPCR signaling via these effectors in reference to precoupling and collision models. Existing knowledge on signaling bias is discussed in relation to these models as a means of developing strategies to produce novel opioid analgesics with an improved side effects profile.
Collapse
Affiliation(s)
- Karim Nagi
- Département de Pharmacologie, Faculté de Médecine, Université de Montréal Montreal, QC, Canada ; Centre de Recherche du CHU Sainte-Justine Montréal, QC, Canada
| | - Graciela Pineyro
- Département de Pharmacologie, Faculté de Médecine, Université de Montréal Montreal, QC, Canada ; Centre de Recherche du CHU Sainte-Justine Montréal, QC, Canada ; Département de Psychiatrie, Faculté de Médecine, Université de Montréal Montréal, QC, Canada
| |
Collapse
|
88
|
Ong EW, Xue L, Olmstead MC, Cahill CM. Prolonged morphine treatment alters δ opioid receptor post-internalization trafficking. Br J Pharmacol 2014; 172:615-29. [PMID: 24819092 PMCID: PMC4292973 DOI: 10.1111/bph.12761] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2013] [Revised: 04/15/2014] [Accepted: 04/29/2014] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND AND PURPOSE The δ opioid receptor (DOP receptor) undergoes internalization both constitutively and in response to agonists. Previous work has shown that DOP receptors traffic from intracellular compartments to neuronal cell membranes following prolonged morphine treatment. Here, we examined the effects of prolonged morphine treatment on the post-internalization trafficking of DOP receptors. EXPERIMENTAL APPROACH Using primary cultures of dorsal root ganglia neurons, we measured the co-localization of endogenous DOP receptors with post-endocytic compartments following both prolonged and acute agonist treatments. KEY RESULTS A departure from the constitutive trafficking pathway was observed following acute DOP receptor agonist-induced internalization by deltorphin II. That is, the DOP receptor underwent distinct agonist-induced post-endocytic sorting. Following prolonged morphine treatment, constitutive DOP receptor trafficking was augmented. SNC80 following prolonged morphine treatment also caused non-constitutive DOP receptor agonist-induced post-endocytic sorting. The μ opioid receptor (MOP receptor) agonist DAMGO induced DOP receptor internalization and trafficking following prolonged morphine treatment. Finally, all of the alterations to DOP receptor trafficking induced by both DOP and MOP receptor agonists were inhibited or absent when those agonists were co-administered with a DOP receptor antagonist, SDM-25N. CONCLUSIONS AND IMPLICATIONS The results support the hypothesis that prolonged morphine treatment induces the formation of MOP–DOP receptor interactions and subsequent augmentation of the available cell surface DOP receptors, at least some of which are in the form of a MOP/DOP receptor species. The pharmacology and trafficking of this species appear to be unique compared to those of its individual constituents. LINKED ARTICLES This article is part of a themed section on Opioids: New Pathways to Functional Selectivity. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-2
Collapse
Affiliation(s)
- E W Ong
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada; Department of Anaesthesiology and Perioperative Care, University of California, Irvine, CA, USA
| | | | | | | |
Collapse
|
89
|
Massotte D. In vivo opioid receptor heteromerization: where do we stand? Br J Pharmacol 2014; 172:420-34. [PMID: 24666391 DOI: 10.1111/bph.12702] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 03/17/2014] [Accepted: 03/19/2014] [Indexed: 12/22/2022] Open
Abstract
UNLABELLED Opioid receptors are highly homologous GPCRs that modulate brain function at all levels of neural integration, including autonomous, sensory, emotional and cognitive processing. Opioid receptors functionally interact in vivo, but the underlying mechanisms involving direct receptor-receptor interactions, affecting signalling pathways or engaging different neuronal circuits, remain unsolved. Heteromer formation through direct physical interaction between two opioid receptors or between an opioid receptor and a non-opioid one has been postulated and can be characterized by specific ligand binding, receptor signalling and trafficking properties. However, despite numerous studies in heterologous systems, evidence for physical proximity in vivo is only available for a limited number of opioid heteromers, and their physiopathological implication remains largely unknown mostly due to the lack of appropriate tools. Nonetheless, data collected so far using endogenous receptors point to a crucial role for opioid heteromers as a molecular entity that could underlie human pathologies such as alcoholism, acute or chronic pain as well as psychiatric disorders. Opioid heteromers therefore stand as new therapeutic targets for the drug discovery field. LINKED ARTICLES This article is part of a themed section on Opioids: New Pathways to Functional Selectivity. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-2.
Collapse
Affiliation(s)
- D Massotte
- Institut des Neurosciences Cellulaires et Intégratives, INCI, Strasbourg, France
| |
Collapse
|
90
|
Borroto-Escuela DO, Brito I, Romero-Fernandez W, Di Palma M, Oflijan J, Skieterska K, Duchou J, Van Craenenbroeck K, Suárez-Boomgaard D, Rivera A, Guidolin D, Agnati LF, Fuxe K. The G protein-coupled receptor heterodimer network (GPCR-HetNet) and its hub components. Int J Mol Sci 2014; 15:8570-90. [PMID: 24830558 PMCID: PMC4057749 DOI: 10.3390/ijms15058570] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 03/26/2014] [Accepted: 04/30/2014] [Indexed: 01/09/2023] Open
Abstract
G protein-coupled receptors (GPCRs) oligomerization has emerged as a vital characteristic of receptor structure. Substantial experimental evidence supports the existence of GPCR-GPCR interactions in a coordinated and cooperative manner. However, despite the current development of experimental techniques for large-scale detection of GPCR heteromers, in order to understand their connectivity it is necessary to develop novel tools to study the global heteroreceptor networks. To provide insight into the overall topology of the GPCR heteromers and identify key players, a collective interaction network was constructed. Experimental interaction data for each of the individual human GPCR protomers was obtained manually from the STRING and SCOPUS databases. The interaction data were used to build and analyze the network using Cytoscape software. The network was treated as undirected throughout the study. It is comprised of 156 nodes, 260 edges and has a scale-free topology. Connectivity analysis reveals a significant dominance of intrafamily versus interfamily connections. Most of the receptors within the network are linked to each other by a small number of edges. DRD2, OPRM, ADRB2, AA2AR, AA1R, OPRK, OPRD and GHSR are identified as hubs. In a network representation 10 modules/clusters also appear as a highly interconnected group of nodes. Information on this GPCR network can improve our understanding of molecular integration. GPCR-HetNet has been implemented in Java and is freely available at http://www.iiia.csic.es/~ismel/GPCR-Nets/index.html.
Collapse
Affiliation(s)
| | - Ismel Brito
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, 17177 Stockholm, Sweden.
| | | | - Michael Di Palma
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, 17177 Stockholm, Sweden.
| | - Julia Oflijan
- Department of Physiology, Faculty of Medicine, University of Tartu, Tartu 50411, Estonia.
| | - Kamila Skieterska
- Laboratory of Eukaryotic Gene Expression and Signal Transduction (LEGEST), Ghent University, 9000 Ghent, Belgium.
| | - Jolien Duchou
- Laboratory of Eukaryotic Gene Expression and Signal Transduction (LEGEST), Ghent University, 9000 Ghent, Belgium.
| | - Kathleen Van Craenenbroeck
- Laboratory of Eukaryotic Gene Expression and Signal Transduction (LEGEST), Ghent University, 9000 Ghent, Belgium.
| | - Diana Suárez-Boomgaard
- Department of Cell Biology, School of Science, University of Málaga, 29071 Málaga, Spain.
| | - Alicia Rivera
- Department of Cell Biology, School of Science, University of Málaga, 29071 Málaga, Spain.
| | - Diego Guidolin
- Department of Molecular Medicine, University of Padova, Padova 35121, Italy.
| | - Luigi F Agnati
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, 17177 Stockholm, Sweden.
| | - Kjell Fuxe
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, 17177 Stockholm, Sweden.
| |
Collapse
|
91
|
Ong EW, Cahill CM. Molecular Perspectives for mu/delta Opioid Receptor Heteromers as Distinct, Functional Receptors. Cells 2014; 3:152-79. [PMID: 24709907 PMCID: PMC3980742 DOI: 10.3390/cells3010152] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 02/14/2014] [Accepted: 02/21/2014] [Indexed: 02/06/2023] Open
Abstract
Opioid receptors are the sites of action for morphine and the other opioid drugs. Abundant evidence now demonstrates that different opioid receptor types can physically associate to form heteromers. Understandings of the nature, behavior, and role of these opioid receptor heteromers are developing. Owing to their constituent monomers’ involvement in analgesia, mu/delta opioid receptor (M/DOR) heteromers have been a particular focus of attention. There is now considerable evidence demonstrating M/DOR to be an extant and physiologically relevant receptor species. Participating in the cellular environment as a distinct receptor type, M/DOR availability is complexly regulated and M/DOR exhibits unique pharmacology from that of other opioid receptors (ORs), including its constituents. M/DOR appears to have a range of actions that vary in a ligand- (or ligands-) dependent manner. These actions can meaningfully affect the clinical effects of opioid drugs: strategies targeting M/DOR may be therapeutically useful. This review presents and discusses developments in these understandings with a focus on the molecular nature and activity of M/DOR in the context of therapeutic potentials.
Collapse
Affiliation(s)
- Edmund W Ong
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada.
| | - Catherine M Cahill
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada.
| |
Collapse
|
92
|
Gomes I, Fujita W, Chandrakala MV, Devi LA. Disease-specific heteromerization of G-protein-coupled receptors that target drugs of abuse. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 117:207-65. [PMID: 23663971 DOI: 10.1016/b978-0-12-386931-9.00009-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Drugs of abuse such as morphine or marijuana exert their effects through the activation of G-protein-coupled receptors (GPCRs), the opioid and cannabinoid receptors, respectively. Moreover, interactions between either of these receptors have been shown to be involved in the rewarding effects of drugs of abuse. Recent advances in the field, using a variety of approaches, have demonstrated that many GPCRs, including opioid, cannabinoid, and dopamine receptors, can form associations between different receptor subtypes or with other GPCRs to form heteromeric complexes. The formation of these complexes, in turn, leads to the modulation of the properties of individual protomers. The development of tools that can selectively disrupt GPCR heteromers as well as monoclonal antibodies that can selectively block signaling by specific heteromer pairs has indicated that heteromers involving opioid, cannabinoid, or dopamine receptors may play a role in various disease states. In this review, we describe evidence for opioid, cannabinoid, and dopamine receptor heteromerization and the potential role of GPCR heteromers in pathophysiological conditions.
Collapse
Affiliation(s)
- Ivone Gomes
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, USA
| | | | | | | |
Collapse
|
93
|
Watts AO, van Lipzig MMH, Jaeger WC, Seeber RM, van Zwam M, Vinet J, van der Lee MMC, Siderius M, Zaman GJR, Boddeke HWGM, Smit MJ, Pfleger KDG, Leurs R, Vischer HF. Identification and profiling of CXCR3-CXCR4 chemokine receptor heteromer complexes. Br J Pharmacol 2013; 168:1662-74. [PMID: 23170857 DOI: 10.1111/bph.12064] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Revised: 09/29/2012] [Accepted: 10/29/2012] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE The C-X-C chemokine receptors 3 (CXCR3) and C-X-C chemokine receptors 4 (CXCR4) are involved in various autoimmune diseases and cancers. Small antagonists have previously been shown to cross-inhibit chemokine binding to CXCR4, CC chemokine receptors 2 (CCR2) and 5 (CCR5) heteromers. We investigated whether CXCR3 and CXCR4 can form heteromeric complexes and the binding characteristics of chemokines and small ligand compounds to these chemokine receptor heteromers. EXPERIMENTAL APPROACH CXCR3-CXCR4 heteromers were identified in HEK293T cells using co-immunoprecipitation, time-resolved fluorescence resonance energy transfer, saturation BRET and the GPCR-heteromer identification technology (HIT) approach. Equilibrium competition binding and dissociation experiments were performed to detect negative binding cooperativity. KEY RESULTS We provide evidence that chemokine receptors CXCR3 and CXCR4 form heteromeric complexes in HEK293T cells. Chemokine binding was mutually exclusive on membranes co-expressing CXCR3 and CXCR4 as revealed by equilibrium competition binding and dissociation experiments. The small CXCR3 agonist VUF10661 impaired binding of CXCL12 to CXCR4, whereas small antagonists were unable to cross-inhibit chemokine binding to the other chemokine receptor. In contrast, negative binding cooperativity between CXCR3 and CXCR4 chemokines was not observed in intact cells. However, using the GPCR-HIT approach, we have evidence for specific β-arrestin2 recruitment to CXCR3-CXCR4 heteromers in response to agonist stimulation. CONCLUSIONS AND IMPLICATIONS This study indicates that heteromeric CXCR3-CXCR4 complexes may act as functional units in living cells, which potentially open up novel therapeutic opportunities.
Collapse
Affiliation(s)
- A O Watts
- Leiden/Amsterdam Center for Drug Research, Division of Medicinal Chemistry, Faculty of Science, VU University Amsterdam, Amsterdam, The Netherlands
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
94
|
|
95
|
Schellekens H, Dinan TG, Cryan JF. Taking two to tango: a role for ghrelin receptor heterodimerization in stress and reward. Front Neurosci 2013; 7:148. [PMID: 24009547 PMCID: PMC3757321 DOI: 10.3389/fnins.2013.00148] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 08/01/2013] [Indexed: 12/25/2022] Open
Abstract
The gut hormone, ghrelin, is the only known peripherally derived orexigenic signal. It activates its centrally expressed receptor, the growth hormone secretagogue receptor (GHS-R1a), to stimulate food intake. The ghrelin signaling system has recently been suggested to play a key role at the interface of homeostatic control of appetite and the hedonic aspects of food intake, as a critical role for ghrelin in dopaminergic mesolimbic circuits involved in reward signaling has emerged. Moreover, enhanced plasma ghrelin levels are associated with conditions of physiological stress, which may underline the drive to eat calorie-dense "comfort-foods" and signifies a role for ghrelin in stress-induced food reward behaviors. These complex and diverse functionalities of the ghrelinergic system are not yet fully elucidated and likely involve crosstalk with additional signaling systems. Interestingly, accumulating data over the last few years has shown the GHS-R1a receptor to dimerize with several additional G-protein coupled receptors (GPCRs) involved in appetite signaling and reward, including the GHS-R1b receptor, the melanocortin 3 receptor (MC3), dopamine receptors (D1 and D2), and more recently, the serotonin 2C receptor (5-HT2C). GHS-R1a dimerization was shown to affect downstream signaling and receptor trafficking suggesting a potential novel mechanism for fine-tuning GHS-R1a receptor mediated activity. This review summarizes ghrelin's role in food reward and stress and outlines the GHS-R1a dimer pairs identified to date. In addition, the downstream signaling and potential functional consequences of dimerization of the GHS-R1a receptor in appetite and stress-induced food reward behavior are discussed. The existence of multiple GHS-R1a heterodimers has important consequences for future pharmacotherapies as it significantly increases the pharmacological diversity of the GHS-R1a receptor and has the potential to enhance specificity of novel ghrelin-targeted drugs.
Collapse
|
96
|
Cascella M, Bärfuss S, Stocker A. Cis-retinoids and the chemistry of vision. Arch Biochem Biophys 2013; 539:187-95. [PMID: 23791723 DOI: 10.1016/j.abb.2013.06.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 06/04/2013] [Accepted: 06/10/2013] [Indexed: 11/17/2022]
Abstract
We discuss here principal biochemical transformations of retinoid molecules in the visual cycle. We focus our analysis on the accumulating evidence of alternate pathways and functional redundancies in the cycle. The efficiency of the visual cycle depends, on one hand, on fast regeneration of the photo-bleached chromophores. On the other hand, it is crucial that the cyclic process should be highly selective to avoid accumulation of byproducts. The state-of-the-art knowledge indicates that single enzymatically active components of the cycle are not strictly selective and may require chaperones to enhance their rates. It appears that protein-protein interactions significantly improve the biological stability of the visual cycle. In particular, synthesis of thermodynamically less stable 11-cis-retinoid conformers is favored by physical interactions of the isomerases present in the retina with cellular retinaldehyde binding protein.
Collapse
Affiliation(s)
- Michele Cascella
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland.
| | | | | |
Collapse
|
97
|
Schmid CL, Streicher JM, Groer CE, Munro TA, Zhou L, Bohn LM. Functional selectivity of 6'-guanidinonaltrindole (6'-GNTI) at κ-opioid receptors in striatal neurons. J Biol Chem 2013; 288:22387-98. [PMID: 23775075 DOI: 10.1074/jbc.m113.476234] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
There is considerable evidence to suggest that drug actions at the κ-opioid receptor (KOR) may represent a means to control pain perception and modulate reward thresholds. As a G protein-coupled receptor (GPCR), the activation of KOR promotes Gαi/o protein coupling and the recruitment of β-arrestins. It has become increasingly evident that GPCRs can transduce signals that originate independently via G protein pathways and β-arrestin pathways; the ligand-dependent bifurcation of such signaling is referred to as "functional selectivity" or "signaling bias." Recently, a KOR agonist, 6'-guanidinonaltrindole (6'-GNTI), was shown to display bias toward the activation of G protein-mediated signaling over β-arrestin2 recruitment. Therefore, we investigated whether such ligand bias was preserved in striatal neurons. Although the reference KOR agonist U69,593 induces the phosphorylation of ERK1/2 and Akt, 6'-GNTI only activates the Akt pathway in striatal neurons. Using pharmacological tools and β-arrestin2 knock-out mice, we show that KOR-mediated ERK1/2 phosphorylation in striatal neurons requires β-arrestin2, whereas Akt activation depends upon G protein signaling. These findings reveal a point of KOR signal bifurcation that can be observed in an endogenous neuronal setting and may prove to be an important indicator when developing biased agonists at the KOR.
Collapse
Affiliation(s)
- Cullen L Schmid
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, Florida 33458, USA
| | | | | | | | | | | |
Collapse
|
98
|
Hiller C, Kühhorn J, Gmeiner P. Class A G-Protein-Coupled Receptor (GPCR) Dimers and Bivalent Ligands. J Med Chem 2013; 56:6542-59. [DOI: 10.1021/jm4004335] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Christine Hiller
- Department of Chemistry and Pharmacy,
Emil Fischer
Center, Friedrich Alexander University,
Schuhstraße 19, 91052 Erlangen, Germany
| | - Julia Kühhorn
- Department of Chemistry and Pharmacy,
Emil Fischer
Center, Friedrich Alexander University,
Schuhstraße 19, 91052 Erlangen, Germany
| | - Peter Gmeiner
- Department of Chemistry and Pharmacy,
Emil Fischer
Center, Friedrich Alexander University,
Schuhstraße 19, 91052 Erlangen, Germany
| |
Collapse
|
99
|
Fujii H, Takahashi T, Nagase H. Non-peptidic δ opioid receptor agonists and antagonists (2000 – 2012). Expert Opin Ther Pat 2013; 23:1181-208. [DOI: 10.1517/13543776.2013.804066] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
|
100
|
Law PY, Reggio PH, Loh HH. Opioid receptors: toward separation of analgesic from undesirable effects. Trends Biochem Sci 2013; 38:275-82. [PMID: 23598157 DOI: 10.1016/j.tibs.2013.03.003] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Revised: 03/06/2013] [Accepted: 03/11/2013] [Indexed: 12/21/2022]
Abstract
The use of opioid analgesics for pain has always been hampered by their many side effects; in particular, the addictive liability associated with chronic use. Recently, attempts to develop analgesic agents with reduced side effects have targeted either the putative opioid receptor splice variants or the receptor hetero-oligomers. This review discusses the potential for receptor splice variant- and the hetero-oligomer-based discovery of new opioid analgesics. We also examine an alternative approach of using receptor mutants for pain management. Finally, we discuss the role of the biased agonism observed and the recently reported opioid receptor crystal structures in guiding the future development of opioid analgesics.
Collapse
Affiliation(s)
- Ping-Yee Law
- Department of Pharmacology, University of Minnesota, Medical School, Minneapolis, MN 55455, USA.
| | | | | |
Collapse
|