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Li Y, Li N, Zhang X, Liu K, Jia Z, Wang G. A modified receptor model for source apportionment of sediment polycyclic aromatic hydrocarbons. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 318:115637. [PMID: 35949089 DOI: 10.1016/j.jenvman.2022.115637] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 06/23/2022] [Accepted: 06/26/2022] [Indexed: 06/15/2023]
Abstract
Polycyclic aromatic hydrocarbons (PAHs) have become a serious threat to human health and ecological security due to their persistence and high toxicity. Lake sediments are in a relatively closed environment, so PAHs and other pollutants can be preserved for a long time. Accurate analysis of the sources of PAHs in sediments is an important prerequisite for PAH pollution control. However, the existing PAHs source resolution receptor model (the absolute principal component analysis - multilinear regression (APCA-MLR) and positive matrix factorization (PMF)) has many defects, such as great uncertainty in the process of matrix rotation. In this study, we collected sediment samples from Taihu Lake and tested their PAH content, and the existing receptor model was improved. High PAH contents were distributed in Meiliang Bay, Zhushan Bay, Gonghu Bay and areas close to the shore. "High-High" areas were distributed in Meiliang Bay, Gonghu Bay and areas close to the shore. "Low-Low" areas appeared in the central and southern parts of Taihu Lake. The results show that the improved positive matrix factorization partition computing (PMF-PC) model is significantly better than the APCA-MLR and PMF models in terms of both numerical simulation accuracy and the spatial distribution consistency of PAHs. The correlations (R2) between the measured and simulated values of low-molecular-weight PAHs (L-PAHs), high-molecular-weight PAHs (H-PAHs) and PAHs were 0.992, 0.989 and 0.993, respectively. The contributions of biomass sources, coal combustion sources and petroleum sources to PAHs in Taihu Lake sediments reached 16.7%, 31.7% and 51.6%, respectively. Fossil fuel sources were mainly concentrated in areas near the shore, and the contribution was lower in areas far from the shore. Although the algorithm still needs to be improved, the PMF-PC model may become a useful tool for the source apportionment of PAHs in sediments.
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Affiliation(s)
- Yan Li
- Collaborative Innovation Center of Sustainable Forestry, Nanjing Forestry University, Nanjing, Jiangsu, China; Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, Jiangsu, China; Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai, China.
| | - Ning Li
- Collaborative Innovation Center of Sustainable Forestry, Nanjing Forestry University, Nanjing, Jiangsu, China
| | - Xiangling Zhang
- Collaborative Innovation Center of Sustainable Forestry, Nanjing Forestry University, Nanjing, Jiangsu, China
| | - Ke Liu
- School of Geography and Ocean Science, Nanjing University, 163 Xianlin Road, Nanjing, Jiangsu, China
| | - Zhenyi Jia
- College of Geography and Environmental Sciences, Zhejiang Normal University, 688 Yingbin Road, Jinhua, Zhejiang, China
| | - Genmei Wang
- Collaborative Innovation Center of Sustainable Forestry, Nanjing Forestry University, Nanjing, Jiangsu, China
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2
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Insights into the dynamics of ligand-induced dimerisation via mathematical modelling and analysis. J Theor Biol 2022; 538:110996. [DOI: 10.1016/j.jtbi.2021.110996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 12/08/2021] [Accepted: 12/20/2021] [Indexed: 11/21/2022]
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3
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Faron-Górecka A, Kuśmider M, Solich J, Górecki A, Dziedzicka-Wasylewska M. Genetic variants in dopamine receptors influence on heterodimerization in the context of antipsychotic drug action. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2019; 169:279-296. [PMID: 31952689 DOI: 10.1016/bs.pmbts.2019.11.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Human dopamine D2 receptor (D2R) gene has polymorphic variants, three of them alter its amino acid sequence: Val96Ala, Pro310Ser and Ser311Cys. Their functional role never became the object of extensive studies, even though there are some evidence that they correlate with schizophrenia. The present work reviews data indicating that these mutations play a role in dimer formation with dopamine D1 receptor (D1R), with the strongest effect observed for Ser311Cys variant. Similarly, the affinity for antipsychotic drugs of this genetic variant depends on whether it is expressed together with D1R or not. Better understanding of altered ability of genetic variants of D2R to form dimers with D1R, as well as of altered affinity for antipsychotic drugs, depending on the absence or presence of the second dopamine receptor is of great importance-since these two receptors are not always co-expressed in the same cell. It may well be that targeting new compounds toward the D1R-D2R dimers, which the most probably form under conditions of excessive dopamine release, will result in antipsychotic drugs devoid of serious side effects.
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Affiliation(s)
- Agata Faron-Górecka
- Department of Pharmacology, Maj Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland.
| | - Maciej Kuśmider
- Department of Pharmacology, Maj Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
| | - Joanna Solich
- Department of Pharmacology, Maj Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
| | - Andrzej Górecki
- Department of Physical Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Marta Dziedzicka-Wasylewska
- Department of Pharmacology, Maj Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland; Department of Physical Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
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Al-Shar'i NA, Al-Balas QA. Molecular Dynamics Simulations of Adenosine Receptors: Advances, Applications and Trends. Curr Pharm Des 2019; 25:783-816. [DOI: 10.2174/1381612825666190304123414] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Accepted: 02/26/2019] [Indexed: 01/09/2023]
Abstract
:
Adenosine receptors (ARs) are transmembrane proteins that belong to the G protein-coupled receptors
(GPCRs) superfamily and mediate the biological functions of adenosine. To date, four AR subtypes are known,
namely A1, A2A, A2B and A3 that exhibit different signaling pathways, tissue localization, and mechanisms of
activation. Moreover, the widespread ARs and their implication in numerous physiological and pathophysiological
conditions had made them pivotal therapeutic targets for developing clinically effective agents.
:
The crystallographic success in identifying the 3D crystal structures of A2A and A1 ARs has dramatically enriched
our understanding of their structural and functional properties such as ligand binding and signal transduction.
This, in turn, has provided a structural basis for a larger contribution of computational methods, particularly molecular
dynamics (MD) simulations, toward further investigation of their molecular properties and designing
bioactive ligands with therapeutic potential. MD simulation has been proved to be an invaluable tool in investigating
ARs and providing answers to some critical questions. For example, MD has been applied in studying ARs
in terms of ligand-receptor interactions, molecular recognition, allosteric modulations, dimerization, and mechanisms
of activation, collectively aiding in the design of subtype selective ligands.
:
In this review, we focused on the advances and different applications of MD simulations utilized to study the
structural and functional aspects of ARs that can foster the structure-based design of drug candidates. In addition,
relevant literature was briefly discussed which establishes a starting point for future advances in the field of drug
discovery to this pivotal group of drug targets.
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Affiliation(s)
- Nizar A. Al-Shar'i
- Department of Medicinal Chemistry and Pharmacognosy, Faculty of Pharmacy, Jordan University of Science and Technology, P.O. Box 3030, Irbid 22110, Jordan
| | - Qosay A. Al-Balas
- Department of Medicinal Chemistry and Pharmacognosy, Faculty of Pharmacy, Jordan University of Science and Technology, P.O. Box 3030, Irbid 22110, Jordan
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5
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An operational model for GPCR homodimers and its application in the analysis of biased signaling. Drug Discov Today 2018; 23:1591-1595. [DOI: 10.1016/j.drudis.2018.04.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 03/28/2018] [Accepted: 04/05/2018] [Indexed: 11/23/2022]
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Ligand Binding Dynamics for Pre-dimerised G Protein-Coupled Receptor Homodimers: Linear Models and Analytical Solutions. Bull Math Biol 2018; 81:3542-3574. [PMID: 29349610 PMCID: PMC6722261 DOI: 10.1007/s11538-017-0387-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 12/21/2017] [Indexed: 11/25/2022]
Abstract
Evidence suggests that many G protein-coupled receptors (GPCRs) are bound together forming dimers. The implications of dimerisation for cellular signalling outcomes, and ultimately drug discovery and therapeutics, remain unclear. Consideration of ligand binding and signalling via receptor dimers is therefore required as an addition to classical receptor theory, which is largely built on assumptions of monomeric receptors. A key factor in developing theoretical models of dimer signalling is cooperativity across the dimer, whereby binding of a ligand to one protomer affects the binding of a ligand to the other protomer. Here, we present and analyse linear models for one-ligand and two-ligand binding dynamics at homodimerised receptors, as an essential building block in the development of dimerised receptor theory. For systems at equilibrium, we compute analytical solutions for total bound labelled ligand and derive conditions on the cooperativity factors under which multiphasic log dose–response curves are expected. This could help explain data extracted from pharmacological experiments that do not fit to the standard Hill curves that are often used in this type of analysis. For the time-dependent problems, we also obtain analytical solutions. For the single-ligand case, the construction of the analytical solution is straightforward; it is bi-exponential in time, sharing a similar structure to the well-known monomeric competition dynamics of Motulsky–Mahan. We suggest that this model is therefore practically usable by the pharmacologist towards developing insights into the potential dynamics and consequences of dimerised receptors.
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Tekko T, Lakspere T, Allikalt A, End J, Kõlvart KR, Jagomäe T, Terasmaa A, Philips MA, Visnapuu T, Väärtnõu F, Gilbert SF, Rinken A, Vasar E, Lilleväli K. Wfs1 is expressed in dopaminoceptive regions of the amniote brain and modulates levels of D1-like receptors. PLoS One 2017; 12:e0172825. [PMID: 28267787 PMCID: PMC5436468 DOI: 10.1371/journal.pone.0172825] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 02/10/2017] [Indexed: 11/27/2022] Open
Abstract
During amniote evolution, the construction of the forebrain has diverged across
different lineages, and accompanying the structural changes, functional
diversification of the homologous brain regions has occurred. This can be
assessed by studying the expression patterns of marker genes that are relevant
in particular functional circuits. In all vertebrates, the dopaminergic system
is responsible for the behavioral responses to environmental stimuli. Here we
show that the brain regions that receive dopaminergic input through dopamine
receptor D1 are relatively conserved, but with some important
variations between three evolutionarily distant vertebrate lines–house mouse
(Mus musculus), domestic chick (Gallus gallus
domesticus) / common quail (Coturnix coturnix) and
red-eared slider turtle (Trachemys scripta). Moreover, we find
that in almost all instances, those brain regions expressing D1-like dopamine
receptor genes also express Wfs1. Wfs1 has been studied
primarily in the pancreas, where it regulates the endoplasmic reticulum (ER)
stress response, cellular Ca2+ homeostasis, and insulin production
and secretion. Using radioligand binding assays in wild type and
Wfs1-/- mouse brains, we show that the number of
binding sites of D1-like dopamine receptors is increased in the hippocampus of
the mutant mice. We propose that the functional link between Wfs1 and D1-like
dopamine receptors is evolutionarily conserved and plays an important role in
adjusting behavioral reactions to environmental stimuli.
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Affiliation(s)
- Triin Tekko
- Department of Physiology, Institute of Biomedicine and Translational
Medicine, University of Tartu, Tartu, Estonia
- Centre of Excellence in Genomics and Translational Medicine, University
of Tartu, Tartu, Estonia
| | - Triin Lakspere
- Department of Developmental Biology, Institute of Molecular and Cell
Biology, University of Tartu, Tartu, Estonia
| | - Anni Allikalt
- Institute of Chemistry, University of Tartu, Tartu,
Estonia
| | - Jaanus End
- Department of Developmental Biology, Institute of Molecular and Cell
Biology, University of Tartu, Tartu, Estonia
| | | | - Toomas Jagomäe
- Department of Physiology, Institute of Biomedicine and Translational
Medicine, University of Tartu, Tartu, Estonia
- Centre of Excellence in Genomics and Translational Medicine, University
of Tartu, Tartu, Estonia
| | - Anton Terasmaa
- Department of Physiology, Institute of Biomedicine and Translational
Medicine, University of Tartu, Tartu, Estonia
- Centre of Excellence in Genomics and Translational Medicine, University
of Tartu, Tartu, Estonia
| | - Mari-Anne Philips
- Department of Physiology, Institute of Biomedicine and Translational
Medicine, University of Tartu, Tartu, Estonia
- Centre of Excellence in Genomics and Translational Medicine, University
of Tartu, Tartu, Estonia
| | - Tanel Visnapuu
- Department of Physiology, Institute of Biomedicine and Translational
Medicine, University of Tartu, Tartu, Estonia
- Centre of Excellence in Genomics and Translational Medicine, University
of Tartu, Tartu, Estonia
| | - Fred Väärtnõu
- Department of Developmental Biology, Institute of Molecular and Cell
Biology, University of Tartu, Tartu, Estonia
| | - Scott F. Gilbert
- Department of Biology, Swarthmore College, Swarthmore, PA, United States
of America
| | - Ago Rinken
- Institute of Chemistry, University of Tartu, Tartu,
Estonia
| | - Eero Vasar
- Department of Physiology, Institute of Biomedicine and Translational
Medicine, University of Tartu, Tartu, Estonia
- Centre of Excellence in Genomics and Translational Medicine, University
of Tartu, Tartu, Estonia
| | - Kersti Lilleväli
- Department of Physiology, Institute of Biomedicine and Translational
Medicine, University of Tartu, Tartu, Estonia
- Centre of Excellence in Genomics and Translational Medicine, University
of Tartu, Tartu, Estonia
- * E-mail:
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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.
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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
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9
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Hints on the Lateralization of Dopamine Binding to D1 Receptors in Rat Striatum. Mol Neurobiol 2015; 53:5436-45. [DOI: 10.1007/s12035-015-9468-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 09/29/2015] [Indexed: 10/23/2022]
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Zhen J, Antonio T, Ali S, Neve KA, Dutta AK, Reith MEA. Use of radiolabeled antagonist assays for assessing agonism at D2 and D3 dopamine receptors: comparison with functional GTPγS assays. J Neurosci Methods 2015; 248:7-15. [PMID: 25840364 DOI: 10.1016/j.jneumeth.2015.03.028] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 03/23/2015] [Accepted: 03/25/2015] [Indexed: 01/13/2023]
Abstract
BACKGROUND Cell-based drug screening assays are essential tools for drug discovery and development targeting G protein-coupled receptors, which include dopamine D3 receptors. D3 is notorious for its poor coupling to G protein in most heterologous cell lines, and therefore D3 agonist-stimulated binding of [(35)S]GTPγS to G protein cannot be observed in many "non-functional" D3 expressing cell lines. NEW METHOD The present work explores the use of an alternate method for assessing agonist activity, consisting of measuring the difference in agonist competition between [(3)H]spiperone bound to low-affinity states of the receptor and that with radioligand bound to high-affinity states (GTP shift assay). COMPARISON WITH EXISTING METHOD The current study describes the determination of GTP shifts in [(3)H]spiperone binding assays for the assessment of agonists' potencies (at D2 and D3) and efficacies (at D3). Compared with GTPγ(35)S binding assays, the new method removes the cumbersome need of functional D3 cell lines and limited project duration due to short half-life of isotope (35)S. CONCLUSION The new method allows the estimation of potency (D2 and D3) and efficacy (D3) at the level of receptor and G protein activation in a simple fashion from shifts in monophasic-inhibition curves. Moreover, it does not require [(35)S]GTPγS binding assays with functional D3 cells. This method will have wide applicability for D3-selective agonist screening. It may also be useful for other GPCRs circumventing the need for functional assays and offering the ability to detect agonist activity regardless of the particular signaling pathway.
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Affiliation(s)
- Juan Zhen
- Department of Psychiatry, New York University School of Medicine, New York, NY, USA.
| | - Tamara Antonio
- Department of Psychiatry, New York University School of Medicine, New York, NY, USA
| | - Solav Ali
- Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY, USA
| | - Kim A Neve
- Research Service, Department of Veterans Affairs Medical Center, Portland, OR, USA
| | - Aloke K Dutta
- Department of Pharmaceutical Sciences, Wayne State University, Detroit, MI, USA
| | - Maarten E A Reith
- Department of Psychiatry, New York University School of Medicine, New York, NY, USA; Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, USA
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11
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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.
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Ferreira SG, Gonçalves FQ, Marques JM, Tomé ÂR, Rodrigues RJ, Nunes-Correia I, Ledent C, Harkany T, Venance L, Cunha RA, Köfalvi A. Presynaptic adenosine A2A receptors dampen cannabinoid CB1 receptor-mediated inhibition of corticostriatal glutamatergic transmission. Br J Pharmacol 2015; 172:1074-86. [PMID: 25296982 DOI: 10.1111/bph.12970] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2014] [Revised: 09/30/2014] [Accepted: 10/03/2014] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND AND PURPOSE Both cannabinoid CB1 and adenosine A2A receptors (CB1 receptors and A2A receptors) control synaptic transmission at corticostriatal synapses, with great therapeutic importance for neurological and psychiatric disorders. A postsynaptic CB1 -A2A receptor interaction has already been elucidated, but the presynaptic A2A receptor-mediated control of presynaptic neuromodulation by CB1 receptors remains to be defined. Because the corticostriatal terminals provide the major input to the basal ganglia, understanding the interactive nature of converging neuromodulation on them will provide us with novel powerful tools to understand the physiology of corticostriatal synaptic transmission and interpret changes associated with pathological conditions. EXPERIMENTAL APPROACH Pharmacological manipulation of CB1 and A2A receptors was carried out in brain nerve terminals isolated from rats and mice, using flow synaptometry, immunoprecipitation, radioligand binding, ATP and glutamate release measurement. Whole-cell patch-clamp recordings were made in horizontal corticostriatal slices. KEY RESULTS Flow synaptometry showed that A2A receptors were extensively co-localized with CB1 receptor-immunopositive corticostriatal terminals and A2A receptors co-immunoprecipitated CB1 receptors in these purified terminals. A2A receptor activation decreased CB1 receptor radioligand binding and decreased the CB1 receptor-mediated inhibition of high-K(+) -evoked glutamate release in corticostriatal terminals. Accordingly, A2A receptor activation prevented CB1 receptor-mediated paired-pulse facilitation and attenuated the CB1 receptor-mediated inhibition of synaptic transmission in glutamatergic synapses of corticostriatal slices. CONCLUSIONS AND IMPLICATIONS Activation of presynaptic A2A receptors dampened CB1 receptor-mediated inhibition of corticostriatal terminals. This constitutes a thus far unrecognized mechanism to modulate the potent CB1 receptor-mediated presynaptic inhibition, allowing frequency-dependent enhancement of synaptic efficacy at corticostriatal synapses.
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Affiliation(s)
- S G Ferreira
- Neuromodulation Group, CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504, Coimbra, Portugal; Laboratory of Neuromodulation and Metabolism, CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504, Coimbra, Portugal; Doctoral Programme in Experimental Biology and Biomedicine, CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504, Coimbra, Portugal; Faculty of Medicine, University of Coimbra, 3004-504, Coimbra, Portugal
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13
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Persuy MA, Sanz G, Tromelin A, Thomas-Danguin T, Gibrat JF, Pajot-Augy E. Mammalian olfactory receptors: molecular mechanisms of odorant detection, 3D-modeling, and structure-activity relationships. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 130:1-36. [PMID: 25623335 DOI: 10.1016/bs.pmbts.2014.11.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
This chapter describes the main characteristics of olfactory receptor (OR) genes of vertebrates, including generation of this large multigenic family and pseudogenization. OR genes are compared in relation to evolution and among species. OR gene structure and selection of a given gene for expression in an olfactory sensory neuron (OSN) are tackled. The specificities of OR proteins, their expression, and their function are presented. The expression of OR proteins in locations other than the nasal cavity is regulated by different mechanisms, and ORs display various additional functions. A conventional olfactory signal transduction cascade is observed in OSNs, but individual ORs can also mediate different signaling pathways, through the involvement of other molecular partners and depending on the odorant ligand encountered. ORs are engaged in constitutive dimers. Ligand binding induces conformational changes in the ORs that regulate their level of activity depending on odorant dose. When present, odorant binding proteins induce an allosteric modulation of OR activity. Since no 3D structure of an OR has been yet resolved, modeling has to be performed using the closest G-protein-coupled receptor 3D structures available, to facilitate virtual ligand screening using the models. The study of odorant binding modes and affinities may infer best-bet OR ligands, to be subsequently checked experimentally. The relationship between spatial and steric features of odorants and their activity in terms of perceived odor quality are also fields of research that development of computing tools may enhance.
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Affiliation(s)
- Marie-Annick Persuy
- INRA UR 1197 NeuroBiologie de l'Olfaction, Domaine de Vilvert, Jouy-en-Josas, France
| | - Guenhaël Sanz
- INRA UR 1197 NeuroBiologie de l'Olfaction, Domaine de Vilvert, Jouy-en-Josas, France
| | - Anne Tromelin
- INRA UMR 1129 Flaveur, Vision et Comportement du Consommateur, Dijon, France
| | | | - Jean-François Gibrat
- INRA UR1077 Mathématique Informatique et Génome, Domaine de Vilvert, Jouy-en-Josas, France
| | - Edith Pajot-Augy
- INRA UR 1197 NeuroBiologie de l'Olfaction, Domaine de Vilvert, Jouy-en-Josas, France.
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14
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Farré D, Muñoz A, Moreno E, Reyes-Resina I, Canet-Pons J, Dopeso-Reyes IG, Rico AJ, Lluís C, Mallol J, Navarro G, Canela EI, Cortés A, Labandeira-García JL, Casadó V, Lanciego JL, Franco R. Stronger Dopamine D1 Receptor-Mediated Neurotransmission in Dyskinesia. Mol Neurobiol 2014; 52:1408-1420. [PMID: 25344317 DOI: 10.1007/s12035-014-8936-x] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2014] [Accepted: 10/09/2014] [Indexed: 11/26/2022]
Abstract
Radioligand binding assays to rat striatal dopamine D1 receptors showed that brain lateralization of the dopaminergic system were not due to changes in expression but in agonist affinity. D1 receptor-mediated striatal imbalance resulted from a significantly higher agonist affinity in the left striatum. D1 receptors heteromerize with dopamine D3 receptors, which are considered therapeutic targets for dyskinesia in parkinsonian patients. Expression of both D3 and D1-D3 receptor heteromers were increased in samples from 6-hydroxy-dopamine-hemilesioned rats rendered dyskinetic by treatment with 3, 4-dihydroxyphenyl-L-alanine (L-DOPA). Similar findings were obtained using striatal samples from primates. Radioligand binding studies in the presence of a D3 agonist led in dyskinetic, but not in lesioned or L-DOPA-treated rats, to a higher dopamine sensitivity. Upon D3-receptor activation, the affinity of agonists for binding to the right striatal D1 receptor increased. Excess dopamine coming from L-DOPA medication likely activates D3 receptors thus making right and left striatal D1 receptors equally responsive to dopamine. These results show that dyskinesia occurs concurrently with a right/left striatal balance in D1 receptor-mediated neurotransmission.
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MESH Headings
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/pharmacology
- Animals
- Caudate Nucleus/drug effects
- Caudate Nucleus/physiopathology
- Corpus Striatum/drug effects
- Corpus Striatum/physiopathology
- Dimerization
- Dominance, Cerebral/drug effects
- Dopamine/metabolism
- Dopamine Agonists/pharmacology
- Dyskinesia, Drug-Induced/etiology
- Dyskinesia, Drug-Induced/physiopathology
- Gene Expression Regulation/drug effects
- Levodopa/pharmacology
- Levodopa/toxicity
- Macaca fascicularis
- Male
- Oxidopamine/toxicity
- Parkinsonian Disorders/chemically induced
- Parkinsonian Disorders/physiopathology
- Putamen/drug effects
- Putamen/physiopathology
- Radioligand Assay
- Rats
- Rats, Wistar
- Receptors, Dopamine D1/agonists
- Receptors, Dopamine D1/biosynthesis
- Receptors, Dopamine D1/genetics
- Receptors, Dopamine D1/physiology
- Receptors, Dopamine D3/biosynthesis
- Receptors, Dopamine D3/genetics
- Receptors, Dopamine D3/physiology
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Affiliation(s)
- Daniel Farré
- Department of Biochemistry and Molecular Biology, Faculty of Biology, Universitat de Barcelona, Diagonal 645, Prevosti Building, 08028, Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Barcelona, Spain
| | - Ana Muñoz
- Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, Center for Research in Molecular Medicine and Chronic Diseases (CIMUS), University of Santiago de Compostela, Santiago de Compostela, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Barcelona, Spain
| | - Estefanía Moreno
- Department of Biochemistry and Molecular Biology, Faculty of Biology, Universitat de Barcelona, Diagonal 645, Prevosti Building, 08028, Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Barcelona, Spain
| | - Irene Reyes-Resina
- Neuroscience Department, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
| | - Júlia Canet-Pons
- Department of Biochemistry and Molecular Biology, Faculty of Biology, Universitat de Barcelona, Diagonal 645, Prevosti Building, 08028, Barcelona, Spain
| | - Iria G Dopeso-Reyes
- Neuroscience Department, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Barcelona, Spain
| | - Alberto J Rico
- Neuroscience Department, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Barcelona, Spain
| | - Carme Lluís
- Department of Biochemistry and Molecular Biology, Faculty of Biology, Universitat de Barcelona, Diagonal 645, Prevosti Building, 08028, Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Barcelona, Spain
| | - Josefa Mallol
- Department of Biochemistry and Molecular Biology, Faculty of Biology, Universitat de Barcelona, Diagonal 645, Prevosti Building, 08028, Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Barcelona, Spain
| | - Gemma Navarro
- Department of Biochemistry and Molecular Biology, Faculty of Biology, Universitat de Barcelona, Diagonal 645, Prevosti Building, 08028, Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Barcelona, Spain
| | - Enric I Canela
- Department of Biochemistry and Molecular Biology, Faculty of Biology, Universitat de Barcelona, Diagonal 645, Prevosti Building, 08028, Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Barcelona, Spain
| | - Antonio Cortés
- Department of Biochemistry and Molecular Biology, Faculty of Biology, Universitat de Barcelona, Diagonal 645, Prevosti Building, 08028, Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Barcelona, Spain
| | - José L Labandeira-García
- Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, Center for Research in Molecular Medicine and Chronic Diseases (CIMUS), University of Santiago de Compostela, Santiago de Compostela, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Barcelona, Spain
| | - Vicent Casadó
- Department of Biochemistry and Molecular Biology, Faculty of Biology, Universitat de Barcelona, Diagonal 645, Prevosti Building, 08028, Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Barcelona, Spain
| | - José L Lanciego
- Neuroscience Department, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Barcelona, Spain
| | - Rafael Franco
- Department of Biochemistry and Molecular Biology, Faculty of Biology, Universitat de Barcelona, Diagonal 645, Prevosti Building, 08028, Barcelona, Spain.
- Neuroscience Department, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain.
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Barcelona, Spain.
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15
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Cortés A, Gracia E, Moreno E, Mallol J, Lluís C, Canela EI, Casadó V. Moonlighting Adenosine Deaminase: A Target Protein for Drug Development. Med Res Rev 2014; 35:85-125. [DOI: 10.1002/med.21324] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Antoni Cortés
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED); Institute of Biomedicine of the University of Barcelona (IBUB); Department of Biochemistry and Molecular Biology; Faculty of Biology; University of Barcelona; Barcelona Spain
| | - Eduard Gracia
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED); Institute of Biomedicine of the University of Barcelona (IBUB); Department of Biochemistry and Molecular Biology; Faculty of Biology; University of Barcelona; Barcelona Spain
| | - Estefania Moreno
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED); Institute of Biomedicine of the University of Barcelona (IBUB); Department of Biochemistry and Molecular Biology; Faculty of Biology; University of Barcelona; Barcelona Spain
| | - Josefa Mallol
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED); Institute of Biomedicine of the University of Barcelona (IBUB); Department of Biochemistry and Molecular Biology; Faculty of Biology; University of Barcelona; Barcelona Spain
| | - Carme Lluís
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED); Institute of Biomedicine of the University of Barcelona (IBUB); Department of Biochemistry and Molecular Biology; Faculty of Biology; University of Barcelona; Barcelona Spain
| | - Enric I. Canela
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED); Institute of Biomedicine of the University of Barcelona (IBUB); Department of Biochemistry and Molecular Biology; Faculty of Biology; University of Barcelona; Barcelona Spain
| | - Vicent Casadó
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED); Institute of Biomedicine of the University of Barcelona (IBUB); Department of Biochemistry and Molecular Biology; Faculty of Biology; University of Barcelona; Barcelona Spain
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16
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Franco N, Franco R. Understanding the added value of g-protein-coupled receptor heteromers. SCIENTIFICA 2014; 2014:362937. [PMID: 24864225 PMCID: PMC4017843 DOI: 10.1155/2014/362937] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 03/10/2014] [Indexed: 06/03/2023]
Abstract
G-protein-coupled receptors (GPCRs) constitute the most populated family of proteins within the human genome. Since the early sixties work on GPCRs and on GPCR-mediated signaling has led to a number of awards, the most recent being the Nobel Prize in Chemistry for 2012. The future of GPCRs research is surely based on their capacity for heteromerization. Receptor heteromers offer a series of challenges that will help in providing success in academic/basic research and translation into more effective and safer drugs.
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Affiliation(s)
- Nuria Franco
- Department Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Prevosti Building, Diagonal 645, 08028 Barcelona, Spain
| | - Rafael Franco
- Department Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Prevosti Building, Diagonal 645, 08028 Barcelona, Spain
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17
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Moreno E, Moreno-Delgado D, Navarro G, Hoffmann HM, Fuentes S, Rosell-Vilar S, Gasperini P, Rodríguez-Ruiz M, Medrano M, Mallol J, Cortés A, Casadó V, Lluís C, Ferré S, Ortiz J, Canela E, McCormick PJ. Cocaine disrupts histamine H3 receptor modulation of dopamine D1 receptor signaling: σ1-D1-H3 receptor complexes as key targets for reducing cocaine's effects. J Neurosci 2014; 34:3545-58. [PMID: 24599455 PMCID: PMC3942573 DOI: 10.1523/jneurosci.4147-13.2014] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Revised: 01/16/2014] [Accepted: 01/27/2014] [Indexed: 01/19/2023] Open
Abstract
The general effects of cocaine are not well understood at the molecular level. What is known is that the dopamine D1 receptor plays an important role. Here we show that a key mechanism may be cocaine's blockade of the histamine H3 receptor-mediated inhibition of D1 receptor function. This blockade requires the σ1 receptor and occurs upon cocaine binding to σ1-D1-H3 receptor complexes. The cocaine-mediated disruption leaves an uninhibited D1 receptor that activates Gs, freely recruits β-arrestin, increases p-ERK 1/2 levels, and induces cell death when over activated. Using in vitro assays with transfected cells and in ex vivo experiments using both rats acutely treated or self-administered with cocaine along with mice depleted of σ1 receptor, we show that blockade of σ1 receptor by an antagonist restores the protective H3 receptor-mediated brake on D1 receptor signaling and prevents the cell death from elevated D1 receptor signaling. These findings suggest that a combination therapy of σ1R antagonists with H3 receptor agonists could serve to reduce some effects of cocaine.
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Affiliation(s)
- Estefanía Moreno
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)
- Institute of Biomedicine of the University of Barcelona (IBUB) and
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Barcelona, 08028 Spain
| | - David Moreno-Delgado
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)
- Institute of Biomedicine of the University of Barcelona (IBUB) and
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Barcelona, 08028 Spain
| | - Gemma Navarro
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)
- Institute of Biomedicine of the University of Barcelona (IBUB) and
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Barcelona, 08028 Spain
| | - Hanne M. Hoffmann
- Neuroscience Institute and Department of Biochemistry and Molecular Biology, Faculty of Medicine, Universitat Autónoma de Barcelona, 08193 Bellaterra, Spain
| | - Silvia Fuentes
- Neuroscience Institute and Department of Biochemistry and Molecular Biology, Faculty of Medicine, Universitat Autónoma de Barcelona, 08193 Bellaterra, Spain
| | - Santi Rosell-Vilar
- Neuroscience Institute and Department of Biochemistry and Molecular Biology, Faculty of Medicine, Universitat Autónoma de Barcelona, 08193 Bellaterra, Spain
| | - Paola Gasperini
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)
- Institute of Biomedicine of the University of Barcelona (IBUB) and
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Barcelona, 08028 Spain
| | - Mar Rodríguez-Ruiz
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)
- Institute of Biomedicine of the University of Barcelona (IBUB) and
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Barcelona, 08028 Spain
| | - Mireia Medrano
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)
- Institute of Biomedicine of the University of Barcelona (IBUB) and
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Barcelona, 08028 Spain
| | - Josefa Mallol
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)
- Institute of Biomedicine of the University of Barcelona (IBUB) and
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Barcelona, 08028 Spain
| | - Antoni Cortés
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)
- Institute of Biomedicine of the University of Barcelona (IBUB) and
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Barcelona, 08028 Spain
| | - Vicent Casadó
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)
- Institute of Biomedicine of the University of Barcelona (IBUB) and
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Barcelona, 08028 Spain
| | - Carme Lluís
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)
- Institute of Biomedicine of the University of Barcelona (IBUB) and
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Barcelona, 08028 Spain
| | - Sergi Ferré
- National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Department of Health and Human Services, Baltimore, Maryland 21224, and
| | - Jordi Ortiz
- Neuroscience Institute and Department of Biochemistry and Molecular Biology, Faculty of Medicine, Universitat Autónoma de Barcelona, 08193 Bellaterra, Spain
| | - Enric Canela
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)
- Institute of Biomedicine of the University of Barcelona (IBUB) and
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Barcelona, 08028 Spain
| | - Peter J. McCormick
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)
- Institute of Biomedicine of the University of Barcelona (IBUB) and
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Barcelona, 08028 Spain
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich, United Kingdom NR4 7TJ
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18
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Ferré S, Casadó V, Devi LA, Filizola M, Jockers R, Lohse MJ, Milligan G, Pin JP, Guitart X. G protein-coupled receptor oligomerization revisited: functional and pharmacological perspectives. Pharmacol Rev 2014; 66:413-34. [PMID: 24515647 DOI: 10.1124/pr.113.008052] [Citation(s) in RCA: 431] [Impact Index Per Article: 43.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Most evidence indicates that, as for family C G protein-coupled receptors (GPCRs), family A GPCRs form homo- and heteromers. Homodimers seem to be a predominant species, with potential dynamic formation of higher-order oligomers, particularly tetramers. Although monomeric GPCRs can activate G proteins, the pentameric structure constituted by one GPCR homodimer and one heterotrimeric G protein may provide a main functional unit, and oligomeric entities can be viewed as multiples of dimers. It still needs to be resolved if GPCR heteromers are preferentially heterodimers or if they are mostly constituted by heteromers of homodimers. Allosteric mechanisms determine a multiplicity of possible unique pharmacological properties of GPCR homomers and heteromers. Some general mechanisms seem to apply, particularly at the level of ligand-binding properties. In the frame of the dimer-cooperativity model, the two-state dimer model provides the most practical method to analyze ligand-GPCR interactions when considering receptor homomers. In addition to ligand-binding properties, unique properties for each GPCR oligomer emerge in relation to different intrinsic efficacy of ligands for different signaling pathways (functional selectivity). This gives a rationale for the use of GPCR oligomers, and particularly heteromers, as novel targets for drug development. Herein, we review the functional and pharmacological properties of GPCR oligomers and provide some guidelines for the application of discrete direct screening and high-throughput screening approaches to the discovery of receptor-heteromer selective compounds.
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Affiliation(s)
- Sergi Ferré
- Integrative Neurobiology Section, National Institute on Drug Abuse, Intramural Research Program, National Institutes on Drug Abuse, Department of Health and Human Services, 333 Cassell Drive, Baltimore, Maryland 21224.
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19
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Pinna A, Bonaventura J, Farré D, Sánchez M, Simola N, Mallol J, Lluís C, Costa G, Baqi Y, Müller CE, Cortés A, McCormick P, Canela EI, Martínez-Pinilla E, Lanciego JL, Casadó V, Armentero MT, Franco R. L-DOPA disrupts adenosine A(2A)-cannabinoid CB(1)-dopamine D(2) receptor heteromer cross-talk in the striatum of hemiparkinsonian rats: biochemical and behavioral studies. Exp Neurol 2014; 253:180-91. [PMID: 24412491 DOI: 10.1016/j.expneurol.2013.12.021] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 11/28/2013] [Accepted: 12/30/2013] [Indexed: 10/25/2022]
Abstract
Long-term therapy with L-3,4-dihydroxyphenylalanine (L-DOPA), still the most effective treatment in Parkinson's disease (PD), is associated with severe motor complications such as dyskinesia. Experimental and clinical data have indicated that adenosine A2A receptor antagonists can provide symptomatic improvement by potentiating L-DOPA efficacy and minimizing its side effects. It is known that the G-protein-coupled adenosine A2A, cannabinoid CB1 and dopamine D2 receptors may interact and form functional A2A-CB1-D2 receptor heteromers in co-transfected cells as well as in rat striatum. These data suggest that treatment with a combination of drugs or a single compound selectively acting on A2A-CB1-D2 heteromers may represent an alternative therapeutic treatment of PD. We investigated the expression of A2A-CB1-D2 receptor heteromers in the striatum of both naïve and hemiparkinsonian rats (HPD-rats) bearing a unilateral 6-hydroxydopamine (6-OHDA) lesion, and assessed how receptor heteromer expression and biochemical properties were affected by L-DOPA treatment. Radioligand binding data showed that A2A-CB1-D2 receptor heteromers are present in the striatum of both naïve and HPD-rats. However, behavioral results indicated that the combined administration of A2A (MSX-3 or SCH58261) and CB1 (rimonabant) receptor antagonists, in the presence of L-DOPA does not produce a response different from administration of the A2A receptor antagonist alone. These behavioral results prompted identification of heteromers in L-DOPA-treated animals. Interestingly, the radioligand binding results in samples from lesioned animals suggest that the heteromer is lost following acute or chronic treatment with L-DOPA.
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Affiliation(s)
- Annalisa Pinna
- National Research Council of Italy (CNR), Institute of Neuroscience-Cagliari, 09124 Cagliari, Italy.
| | - Jordi Bonaventura
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas, Spain
| | - Daniel Farré
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas, Spain
| | - Marta Sánchez
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas, Spain
| | - Nicola Simola
- Department of Biomedical Sciences, University of Cagliari, 09124 Cagliari, Italy
| | - Josefa Mallol
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas, Spain
| | - Carme Lluís
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas, Spain
| | - Giulia Costa
- Department of Biomedical Sciences, University of Cagliari, 09124 Cagliari, Italy
| | - Younis Baqi
- PharmaCenter Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry I, University of Bonn, Germany
| | - Christa E Müller
- PharmaCenter Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry I, University of Bonn, Germany
| | - Antoni Cortés
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas, Spain
| | - Peter McCormick
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas, Spain
| | - Enric I Canela
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas, Spain
| | - Eva Martínez-Pinilla
- Centro de Investigación Médica Aplicada, Universidad de Navarra, 31008 Pamplona, Spain
| | - José L Lanciego
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas, Spain; Centro de Investigación Médica Aplicada, Universidad de Navarra, 31008 Pamplona, Spain
| | - Vicent Casadó
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas, Spain
| | - Marie-Therese Armentero
- Laboratory of Functional Neurochemistry, C. Mondino National Neurological Institute, via Mondino 2, Pavia, Italy
| | - Rafael Franco
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain; Centro de Investigación Médica Aplicada, Universidad de Navarra, 31008 Pamplona, Spain
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20
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Roche D, Gil D, Giraldo J. Mathematical modeling of G protein-coupled receptor function: what can we learn from empirical and mechanistic models? ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 796:159-81. [PMID: 24158805 DOI: 10.1007/978-94-007-7423-0_8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Empirical and mechanistic models differ in their approaches to the analysis of pharmacological effect. Whereas the parameters of the former are not physical constants those of the latter embody the nature, often complex, of biology. Empirical models are exclusively used for curve fitting, merely to characterize the shape of the E/[A] curves. Mechanistic models, on the contrary, enable the examination of mechanistic hypotheses by parameter simulation. Regretfully, the many parameters that mechanistic models may include can represent a great difficulty for curve fitting, representing, thus, a challenge for computational method development. In the present study some empirical and mechanistic models are shown and the connections, which may appear in a number of cases between them, are analyzed from the curves they yield. It may be concluded that systematic and careful curve shape analysis can be extremely useful for the understanding of receptor function, ligand classification and drug discovery, thus providing a common language for the communication between pharmacologists and medicinal chemists.
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Affiliation(s)
- David Roche
- Laboratory of Systems Pharmacology and Bioinformatics, Institut de Neurociències and Unitat de Bioestadística, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain
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L-DOPA-treatment in primates disrupts the expression of A(2A) adenosine-CB(1) cannabinoid-D(2) dopamine receptor heteromers in the caudate nucleus. Neuropharmacology 2013; 79:90-100. [PMID: 24230991 DOI: 10.1016/j.neuropharm.2013.10.036] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 10/21/2013] [Accepted: 10/23/2013] [Indexed: 11/21/2022]
Abstract
The molecular basis of priming for L-DOPA-induced dyskinesias in Parkinson's disease (PD), which depends on the indirect pathway of motor control, is not known. In rodents, the indirect pathway contains striatopallidal GABAergic neurons that express heterotrimers composed of A(2A) adenosine, CB(1) cannabinoid and D(2) dopamine receptors that regulate dopaminergic neurotransmission. The present study was designed to investigate the expression of these heteromers in the striatum of a primate model of Parkinson's disease and to determine whether their expression and pharmacological properties are altered upon L-DOPA treatment. By using the recently developed in situ proximity ligation assay and by identification of a biochemical fingerprint, we discovered a regional distribution of A(2A)/CB(1) /D(2) receptor heteromers that predicts differential D(2)-mediated neurotransmission in the caudate-putamen of Macaca fascicularis. Whereas heteromers were abundant in the caudate nucleus of both naïve and MPTP-treated monkeys, L-DOPA treatment blunted the biochemical fingerprint and led to weak heteromer expression. These findings constitute the first evidence of altered receptor heteromer expression in pathological conditions and suggest that drugs targeting A(2A)-CB(1) -D(2) receptor heteromers may be successful to either normalize basal ganglia output or prevent L-DOPA-induced side effects.
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Robertson S, Rohwer JM, Hapgood JP, Louw A. Impact of glucocorticoid receptor density on ligand-independent dimerization, cooperative ligand-binding and basal priming of transactivation: a cell culture model. PLoS One 2013; 8:e64831. [PMID: 23717665 PMCID: PMC3661511 DOI: 10.1371/journal.pone.0064831] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Accepted: 04/18/2013] [Indexed: 11/26/2022] Open
Abstract
Glucocorticoid receptor (GR) levels vary between tissues and individuals and are altered by physiological and pharmacological effectors. However, the effects and implications of differences in GR concentration have not been fully elucidated. Using three statistically different GR concentrations in transiently transfected COS-1 cells, we demonstrate, using co-immunoprecipitation (CoIP) and fluorescent resonance energy transfer (FRET), that high levels of wild type GR (wtGR), but not of dimerization deficient GR (GRdim), display ligand-independent dimerization. Whole-cell saturation ligand-binding experiments furthermore establish that positive cooperative ligand-binding, with a concomitant increased ligand-binding affinity, is facilitated by ligand-independent dimerization at high concentrations of wtGR, but not GRdim. The down-stream consequences of ligand-independent dimerization at high concentrations of wtGR, but not GRdim, are shown to include basal priming of the system as witnessed by ligand-independent transactivation of both a GRE-containing promoter-reporter and the endogenous glucocorticoid (GC)-responsive gene, GILZ, as well as ligand-independent loading of GR onto the GILZ promoter. Pursuant to the basal priming of the system, addition of ligand results in a significantly greater modulation of transactivation potency than would be expected solely from the increase in ligand-binding affinity. Thus ligand-independent dimerization of the GR at high concentrations primes the system, through ligand-independent DNA loading and transactivation, which together with positive cooperative ligand-binding increases the potency of GR agonists and shifts the bio-character of partial GR agonists. Clearly GR-levels are a major factor in determining the sensitivity to GCs and a critical factor regulating transcriptional programs.
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Affiliation(s)
- Steven Robertson
- Department of Biochemistry, University of Stellenbosch, Matieland, Stellenbosch, Republic of South Africa
| | - Johann M. Rohwer
- Department of Biochemistry, University of Stellenbosch, Matieland, Stellenbosch, Republic of South Africa
| | - Janet P. Hapgood
- Department of Molecular and Cell Biology, University of Cape Town, Cape Town, Republic of South Africa
| | - Ann Louw
- Department of Biochemistry, University of Stellenbosch, Matieland, Stellenbosch, Republic of South Africa
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Gracia E, Moreno E, Cortés A, Lluís C, Mallol J, McCormick PJ, Canela EI, Casadó V. Homodimerization of adenosine A₁ receptors in brain cortex explains the biphasic effects of caffeine. Neuropharmacology 2013; 71:56-69. [PMID: 23523559 DOI: 10.1016/j.neuropharm.2013.03.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2012] [Revised: 02/27/2013] [Accepted: 03/12/2013] [Indexed: 11/30/2022]
Abstract
Using bioluminescence resonance energy transfer and proximity ligation assays, we obtained the first direct evidence that adenosine A₁ receptors (A₁Rs) form homomers not only in cell cultures but also in brain cortex. By radioligand binding experiments in the absence or in the presence of the A₁Rs allosteric modulator, adenosine deaminase, and by using the two-state dimer receptor model to fit binding data, we demonstrated that the protomer-protomer interactions in the A₁R homomers account for some of the pharmacological characteristics of agonist and antagonist binding to A₁Rs. These pharmacological properties include the appearance of cooperativity in agonist binding, the change from a biphasic saturation curve to a monophasic curve in self-competition experiments and the molecular cross-talk detected when two different specific molecules bind to the receptor. In this last case, we discovered that caffeine binding to one protomer increases the agonist affinity for the other protomer in the A₁R homomer, a pharmacological characteristic that correlates with the low caffeine concentrations-induced activation of agonist-promoted A₁R signaling. This pharmacological property can explain the biphasic effects reported at low and high concentration of caffeine on locomotor activity.
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Affiliation(s)
- Eduard Gracia
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Faculty of Biology, University of Barcelona, Av. Diagonal 643, 08028 Barcelona, Spain.
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24
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Franco R, Martínez-Pinilla E, Ricobaraza A, McCormick PJ. Challenges in the development of heteromer-GPCR-based drugs. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 117:143-62. [PMID: 23663968 DOI: 10.1016/b978-0-12-386931-9.00006-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
G-protein-coupled receptors are targets of a variety of diseases. Drug screening has been classically performed assuming the occurrence of monomeric receptors. As more and more receptor heteromers are identified, the challenge is now to develop screening assays to select heteromer-specific drugs. These drugs may, for instance, be able to interact preferentially with prerather than with postsynaptic receptors. Heteromer-based drug discovery opens new perspectives in both Academic pursuits and for the Pharmaceutical industry.
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Affiliation(s)
- Rafael Franco
- Applied Medical Research Center (CIMA), University of Navarra, Pamplona, Spain
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25
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Giraldo J. Modeling cooperativity effects in dimeric G protein-coupled receptors. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 115:349-73. [PMID: 23415098 DOI: 10.1016/b978-0-12-394587-7.00008-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
G protein-coupled receptors organize into oligomeric arrangements to exert their function. In this chapter, three models of dimeric receptors, the two-state dimer receptor model, the metabotropic glutamate receptor model, and the asymmetric/symmetric three-state dimer receptor model are revisited focusing on the cooperative effects between their binding sites and the subunits they are composed of. The mathematical analysis reveals the complexity of the intra-receptor interactions providing insights on the mechanistic aspects of receptor function.
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Affiliation(s)
- Jesús Giraldo
- Laboratory of Systems Pharmacology and Bioinformatics, Institut de Neurociències and Unitat de Bioestadística, Universitat Autònoma de Barcelona, Bellaterra, Spain
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26
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May LT, Bridge LJ, Stoddart LA, Briddon SJ, Hill SJ. Allosteric interactions across native adenosine-A3 receptor homodimers: quantification using single-cell ligand-binding kinetics. FASEB J 2011; 25:3465-76. [PMID: 21715680 PMCID: PMC3177574 DOI: 10.1096/fj.11-186296] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A growing awareness indicates that many G-protein-coupled receptors (GPCRs) exist as homodimers, but the extent of the cooperativity across the dimer interface has been largely unexplored. Here, measurement of the dissociation kinetics of a fluorescent agonist (ABA-X-BY630) from the human A1 or A3 adenosine receptors expressed in CHO-K1 cells has provided evidence for highly cooperative interactions between protomers of the A3-receptor dimer in single living cells. In the absence of competitive ligands, the dissociation rate constants of ABA-X-BY630 from A1 and A3 receptors were 1.45 ± 0.05 and 0.57 ± 0.07 min−1, respectively. At the A3 receptor, this could be markedly increased by both orthosteric agonists and antagonists [15-, 9-, and 19-fold for xanthine amine congener (XAC), 5′-(N-ethyl carboxamido)adenosine (NECA), and adenosine, respectively] and reduced by coexpression of a nonbinding (N250A) A3-receptor mutant. The changes in ABA-X-BY630 dissociation were much lower at the A1 receptor (1.5-, 1.4-, and 1.5-fold). Analysis of the pEC50 values of XAC, NECA, and adenosine for the ABA-X-BY630-occupied A3-receptor dimer yielded values of 6.0 ± 0.1, 5.9 ± 0.1, and 5.2 ± 0.1, respectively. This study provides new insight into the spatial and temporal specificity of drug action that can be provided by allosteric modulation across a GPCR homodimeric interface.—May, L. T., Bridge, L. J., Stoddart, L. A., Briddon, S. J., Hill, S. J. Allosteric interactions across native adenosine-A3 receptor homodimers: quantification using single-cell ligand-binding kinetics.
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Affiliation(s)
- Lauren T May
- Institute of Cell Signalling, School of Biomedical Sciences, The University of Nottingham, Nottingham, UK, NG7 2UH
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27
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Guidolin D, Ciruela F, Genedani S, Guescini M, Tortorella C, Albertin G, Fuxe K, Agnati LF. Bioinformatics and mathematical modelling in the study of receptor–receptor interactions and receptor oligomerization. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:1267-83. [DOI: 10.1016/j.bbamem.2010.09.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2010] [Revised: 08/31/2010] [Accepted: 09/26/2010] [Indexed: 10/19/2022]
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28
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A2A adenosine receptor ligand binding and signalling is allosterically modulated by adenosine deaminase. Biochem J 2011; 435:701-9. [DOI: 10.1042/bj20101749] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
A2ARs (adenosine A2A receptors) are highly enriched in the striatum, which is the main motor control CNS (central nervous system) area. BRET (bioluminescence resonance energy transfer) assays showed that A2AR homomers may act as cell-surface ADA (adenosine deaminase; EC 3.5.4.4)-binding proteins. ADA binding affected the quaternary structure of A2ARs present on the cell surface. ADA binding to adenosine A2ARs increased both agonist and antagonist affinity on ligand binding to striatal membranes where these proteins are co-expressed. ADA also increased receptor-mediated ERK1/2 (extracellular-signal-regulated kinase 1/2) phosphorylation. Collectively, the results of the present study show that ADA, apart from regulating the concentration of extracellular adenosine, may behave as an allosteric modulator that markedly enhances ligand affinity and receptor function. This powerful regulation may have implications for the physiology and pharmacology of neuronal A2ARs.
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Franco R, Seeman P, Barrera C, Aymerich MS. Cocaine self-administration markedly increases dopamine D2receptor negative cooperativity for dopamine binding: A receptor dimer-based analysis. Synapse 2010; 64:566-9. [DOI: 10.1002/syn.20775] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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30
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Casadó V, Barrondo S, Spasic M, Callado LF, Mallol J, Canela E, Lluís C, Meana J, Cortés A, Sallés J, Franco R. Gi protein coupling to adenosine A1-A2A receptor heteromers in human brain caudate nucleus. J Neurochem 2010; 114:972-80. [PMID: 20477947 DOI: 10.1111/j.1471-4159.2010.06810.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Pharmacological characterization of adenosine A(1) and A(2A) receptors in human brain caudate nucleus membranes led to non-cooperative binding of radiolabelled ligands. In human caudate nucleus but not in cortex, the agonist binding to A(1) receptors was modulated by the agonist binding to A(2A) receptors indicating a functional negative cross-talk. Accordingly, the A(1) receptor-activation-mediated G(i)-dependent guanosine 5'-o-(3-[(35)S]thio-triphosphate) binding was modulated by agonist binding to A(2A) receptors. A(2A) receptors occupation led to a decrease in the potency of A(1) receptor agonists. These results indicate that A(1) but not A(2A) receptors activation, likely occurring at low adenosine concentrations, engages a G(i)-mediated signaling; however, when both receptors are occupied by adenosine, there is an A(2A) receptor-mediated impairment of G(i)-operated transducing units. These findings are relevant to get insight into the complex relationships derived from co-expression of multiple neurotransmitter/neuromodulator receptors subtypes that individually are coupled to different G proteins. A further finding was the demonstration that the A(2A) receptor agonist, CGS 21680, at high concentrations able to significantly bind to the A(1) receptor, behaved as a partial agonist of the later receptor. This fact might be taken into account when characterizing CGS 21680 actions in human cells expressing A(1) receptors when the compound is used at micromolar concentrations.
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Affiliation(s)
- Vicent Casadó
- Biochemistry and Molecular Biology Department, University of Barcelona, Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, CIBERNED, Barcelona, Spain
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31
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Kenakin T, Miller LJ. Seven transmembrane receptors as shapeshifting proteins: the impact of allosteric modulation and functional selectivity on new drug discovery. Pharmacol Rev 2010; 62:265-304. [PMID: 20392808 DOI: 10.1124/pr.108.000992] [Citation(s) in RCA: 458] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
It is useful to consider seven transmembrane receptors (7TMRs) as disordered proteins able to allosterically respond to a number of binding partners. Considering 7TMRs as allosteric systems, affinity and efficacy can be thought of in terms of energy flow between a modulator, conduit (the receptor protein), and a number of guests. These guests can be other molecules, receptors, membrane-bound proteins, or signaling proteins in the cytosol. These vectorial flows of energy can yield standard canonical guest allostery (allosteric modification of drug effect), effects along the plane of the cell membrane (receptor oligomerization), or effects directed into the cytosol (differential signaling as functional selectivity). This review discusses these apparently diverse pharmacological effects in terms of molecular dynamics and protein ensemble theory, which tends to unify 7TMR behavior toward cells. Special consideration will be given to functional selectivity (biased agonism and biased antagonism) in terms of mechanism of action and potential therapeutic application. The explosion of technology that has enabled observation of diverse 7TMR behavior has also shown how drugs can have multiple (pluridimensional) efficacies and how this can cause paradoxical drug classification and nomenclatures.
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Affiliation(s)
- Terry Kenakin
- GlaxoSmithKline, 5 Moore Drive, Mailtstop V-287, Research Triangle Park, NC 27709, USA.
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32
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Franco R, Canela EI, Casado V, Ferre S. Platforms for the identification of GPCR targets, and of orthosteric and allosteric modulators. Expert Opin Drug Discov 2010; 5:391-403. [DOI: 10.1517/17460441003653163] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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33
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Feng JJ, Cheng FC, Lin CH, Wei JW, Yang SD. Discovery and characterization of [3H]8-OH-DPAT binding to HeLaS3 cells. Arch Biochem Biophys 2010; 495:14-20. [PMID: 20018167 DOI: 10.1016/j.abb.2009.12.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2009] [Revised: 12/03/2009] [Accepted: 12/06/2009] [Indexed: 11/30/2022]
Abstract
Some G protein-coupled receptors (GPCRs) have functional links to cancer biology, yet the manifestation of GPCRs in tumor types is little studied to date. Using a battery of radioligand binding assays, we sought to characterize GPCR recognition binding sites on HeLaS3 tumor cells. High levels of binding of the selective serotonin 5-HT(1A) receptor agonist [3H]8-OH-DPAT were observed in these cells. Saturation and homologous competition experiments indicated that [3H]8-OH-DPAT bound different populations of high- and low-affinity sites. In competition experiments, several serotonergic compounds displaced [3H]8-OH-DPAT binding with low potency from its high-affinity binding sites, suggesting that low-affinity binding is the predominant mode of binding. A variety of drugs targeting different classes of receptors did not affect [3H]8-OH-DPAT binding. These observations may help elucidate the pathophysiological and functional relevance of 5-HT receptors in tumor cells and link GPCRs and tumorigenic mechanisms to pharmacological and chemotherapeutic paradigms.
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Affiliation(s)
- Jin-Jye Feng
- Institute of Molecular and Cellular Biology, National Tsing Hua University, 101 Section 2 Kuang-Fu Road, Hsinchu 30013, Taiwan, ROC.
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34
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The asymmetric/symmetric activation of GPCR dimers as a possible mechanistic rationale for multiple signalling pathways. Trends Pharmacol Sci 2010; 31:15-21. [DOI: 10.1016/j.tips.2009.10.008] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Revised: 10/23/2009] [Accepted: 10/26/2009] [Indexed: 11/16/2022]
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35
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Soriano A, Vendrell M, Gonzalez S, Mallol J, Albericio F, Royo M, Lluís C, Canela EI, Franco R, Cortés A, Casadó V. A hybrid indoloquinolizidine peptide as allosteric modulator of dopamine D1 receptors. J Pharmacol Exp Ther 2009; 332:876-85. [PMID: 20026675 DOI: 10.1124/jpet.109.158824] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The indoloquinolizidine-peptide 28 [(3S,12bR)-N-((S)-1-((S)-1-((S)-2-carbamoylpyrrolidin-1-yl)-3-(4-fluorophenyl)-1-oxopropan-2-ylamino)-4-cyclohexyl-1-oxobutan-2-yl)-1,2,3,4,6,7,12, 12b-octahydroindolo[2,3-a]quinolizine-3-carboxamide], a trans-indoloquinolizidine-peptide hybrid obtained by a combinatorial approach, behaved as an orthosteric ligand of all dopamine D(2)-like receptors (D(2), D(3), and D(4)) and dopamine D(5) receptors, but as a negative allosteric modulator of agonist and antagonist binding to striatal dopamine D(1) receptors. Indoloquinolizidine-peptide 28 induced a concentration-dependent hyperbolic increase in the antagonist apparent equilibrium dissociation constant values and altered the dissociation kinetics of dopamine D(1) receptor antagonists. The negative allosteric modulation was also found when agonist binding to D(1) receptors was assayed. Indoloquinolizidine-peptide 28 was a weak ago-allosteric modulator but markedly led to a decreased potency without decreasing the maximum partial/full agonist-mediated effect on cAMP levels. Compounds able to decrease the potency while preserving the efficacy of D(1) receptor agonists are promising for exploration in psychotic pathologies.
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Affiliation(s)
- Aroa Soriano
- Department of Biochemistry and Molecular Biology, University of Barcelona, Barcelona, Spain
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36
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Soriano A, Ventura R, Molero A, Hoen R, Casadó V, Cortés A, Fanelli F, Albericio F, Lluís C, Franco R, Royo M. Adenosine A2A receptor-antagonist/dopamine D2 receptor-agonist bivalent ligands as pharmacological tools to detect A2A-D2 receptor heteromers. J Med Chem 2009; 52:5590-602. [PMID: 19711895 DOI: 10.1021/jm900298c] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Adenosine A(2A) (A(2A)R) and dopamine D(2) (D(2)R) receptors mediate the antagonism between adenosinergic and dopaminergic transmission in striatopallidal GABAergic neurons and are pharmacological targets for the treatment of Parkinson's disease. Here, a family of heterobivalent ligands containing a D(2)R agonist and an A(2A)R antagonist linked through a spacer of variable size was designed and synthesized to study A(2A)R-D(2)R heteromers. Bivalent ligands with shorter linkers bound to D(2)R or A(2A)R with higher affinity than the corresponding monovalent controls in membranes from brain striatum and from cells coexpressing both receptors. In contrast, no differences in affinity of bivalent versus monovalent ligands were detected in experiments using membranes from cells expressing only one receptor. These findings indicate the existence of A(2A)R-D(2)R heteromers and of a simultaneous interaction of heterobivalent ligands with both receptors. The cooperative effect derived from the simultaneous interaction suggests the occurrence of A(2A)R-D(2)R heteromers in cotransfected cells and in brain striatum. The dopamine/adenosine bivalent action could constitute a novel concept in Parkinson's disease pharmacotherapy.
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Affiliation(s)
- Aroa Soriano
- Institut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS), Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), and Department of Biochemistry and Molecular Biology, University of Barcelona, Avenida Diagonal 645, E-08028 Barcelona, Spain
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Casadó V, Cortés A, Mallol J, Pérez-Capote K, Ferré S, Lluis C, Franco R, Canela EI. GPCR homomers and heteromers: a better choice as targets for drug development than GPCR monomers? Pharmacol Ther 2009; 124:248-57. [PMID: 19664655 DOI: 10.1016/j.pharmthera.2009.07.005] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2009] [Accepted: 07/21/2009] [Indexed: 10/20/2022]
Abstract
G protein-coupled receptors (GPCR) are targeted by many therapeutic drugs marketed to fight against a variety of diseases. Selection of novel lead compounds are based on pharmacological parameters obtained assuming that GPCR are monomers. However, many GPCR are expressed as dimers/oligomers. Therefore, drug development may consider GPCR as homo- and hetero-oligomers. A two-state dimer receptor model is now available to understand GPCR operation and to interpret data obtained from drugs interacting with dimers, and even from mixtures of monomers and dimers. Heteromers are distinct entities and therefore a given drug is expected to have different affinities and different efficacies depending on the heteromer. All these concepts would lead to broaden the therapeutic potential of drugs targeting GPCRs, including receptor heteromer-selective drugs with a lower incidence of side effects, or to identify novel pharmacological profiles using cell models expressing receptor heteromers.
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Affiliation(s)
- Vicent Casadó
- Departament de Bioquímica i Biologia Molecular, CIBERNED (Centro de Investigación en Red de Enfermedades Neurodegenerativas) and Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) Universitat de Barcelona, 08028 Barcelona, Catalonia, Spain
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38
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Casadó V, Ferrada C, Bonaventura J, Gracia E, Mallol J, Canela EI, Lluís C, Cortés A, Franco R. Useful pharmacological parameters for G-protein-coupled receptor homodimers obtained from competition experiments. Agonist-antagonist binding modulation. Biochem Pharmacol 2009; 78:1456-63. [PMID: 19643089 DOI: 10.1016/j.bcp.2009.07.012] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2009] [Revised: 07/16/2009] [Accepted: 07/20/2009] [Indexed: 11/26/2022]
Abstract
Many G-protein-coupled receptors (GPCRs) are expressed on the plasma membrane as dimers. Since drug binding data are currently fitted using equations developed for monomeric receptors, the interpretation of the pharmacological data are equivocal in many cases. As reported here, GPCR dimer models account for changes in competition curve shape as a function of the radioligand concentration used, something that cannot be explained by monomeric receptor models. Macroscopic equilibrium dissociation constants for the agonist and homotropic cooperativity index reflecting the intramolecular communication within the dopamine D1 or adenosine A2A receptor homodimer as well as hybrid equilibrium dissociation constant, which reflects the antagonist/agonist modulation may be calculated by fitting binding data from antagonist/agonist competition experiments to equations developed from dimer receptor models. Comparing fitting the data by assuming a classical monomeric receptor model or a dimer model, it is shown that dimer receptor models provide more clues useful in drug discovery than monomer-based models.
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Affiliation(s)
- Vicent Casadó
- Institut d'Investigacions Biomèdiques August Pi i Sunyer, Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Avda. Diagonal 465, 08028 Barcelona, Spain.
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Ferrada C, Moreno E, Casadó V, Bongers G, Cortés A, Mallol J, Canela EI, Leurs R, Ferré S, Lluís C, Franco R. Marked changes in signal transduction upon heteromerization of dopamine D1 and histamine H3 receptors. Br J Pharmacol 2009; 157:64-75. [PMID: 19413572 DOI: 10.1111/j.1476-5381.2009.00152.x] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND AND PURPOSE Functional interactions between the G protein-coupled dopamine D1 and histamine H3 receptors have been described in the brain. In the present study we investigated the existence of D1-H3 receptor heteromers and their biochemical characteristics. EXPERIMENTAL APPROACH D1-H3 receptor heteromerization was studied in mammalian transfected cells with Bioluminescence Resonance Energy Transfer and binding assays. Furthermore, signalling through mitogen-activated protein kinase (MAPK) and adenylyl cyclase pathways was studied in co-transfected cells and compared with cells transfected with either D1 or H3 receptors. KEY RESULTS Bioluminescence Resonance Energy Transfer and binding assays confirmed that D1 and H3 receptors can heteromerize. Activation of histamine H3 receptors did not lead to signalling towards the MAPK pathway unless dopamine D1 receptors were co-expressed. Also, dopamine D1 receptors, usually coupled to G(s) proteins and leading to increases in cAMP, did not couple to G(s) but to G(i) in co-transfected cells. Furthermore, signalling via each receptor was blocked not only by a selective antagonist but also by an antagonist of the partner receptor. CONCLUSIONS AND IMPLICATIONS D1-H3 receptor heteromers constitute unique devices that can direct dopaminergic and histaminergic signalling towards the MAPK pathway in a G(s)-independent and G(i)-dependent manner. An antagonist of one of the receptor units in the D1-H3 receptor heteromer can induce conformational changes in the other receptor unit and block specific signals originating in the heteromer. This gives rise to unsuspected therapeutic potentials for G protein-coupled receptor antagonists.
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Affiliation(s)
- Carla Ferrada
- Molecular Neurobiology Unit, IDIBAPS, CIBERNED, Department of Biochemistry and Molecular Biology, School of Biology, University of Barcelona, Barcelona, Spain
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Rovira X, Vivó M, Serra J, Roche D, Strange PG, Giraldo J. Modelling the interdependence between the stoichiometry of receptor oligomerization and ligand binding for a coexisting dimer/tetramer receptor system. Br J Pharmacol 2009; 156:28-35. [PMID: 19133989 DOI: 10.1111/j.1476-5381.2008.00031.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Many G protein-coupled receptors have been shown to exist as oligomers, but the oligomerization state and the effects of this on receptor function are unclear. For some G protein-coupled receptors, in ligand binding assays, different radioligands provide different maximal binding capacities. Here we have developed mathematical models for co-expressed dimeric and tetrameric species of receptors. We have considered models where the dimers and tetramers are in equilibrium and where they do not interconvert and we have also considered the potential influence of the ligands on the degree of oligomerization. By analogy with agonist efficacy, we have considered ligands that promote, inhibit or have no effect on oligomerization. Cell surface receptor expression and the intrinsic capacity of receptors to oligomerize are quantitative parameters of the equations. The models can account for differences in the maximal binding capacities of radioligands in different preparations of receptors and provide a conceptual framework for simulation and data fitting in complex oligomeric receptor situations.
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Affiliation(s)
- X Rovira
- Grup Biomatemàtic de Recerca, Institut de Neurociències and Unitat de Bioestadística, Universitat Autònoma de Barcelona, Bellaterra, Spain
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41
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Franco R. G-protein-coupled receptor heteromers or how neurons can display differently flavoured patterns in response to the same neurotransmitter. Br J Pharmacol 2009; 158:23-31. [PMID: 19422387 DOI: 10.1111/j.1476-5381.2009.00181.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
It is becoming accepted that G-protein-coupled receptors (GPCRs) arrange in the neuronal membrane into homo- and hetero-oligomers and, therefore, these complexes mediate neurotransmission. New models are then needed to understand GPCR operation and predict the consequences of GPCR homo- or hetero-oligomerization. Although there is not any unifying theory addressing how hetero-oligomerization occurs, recent models have been devised to understand the thermodynamics of binding of neurotransmitters to GPCRs and the allosteric protomer-protomer interactions involved in neurotransmitter-mediated activation of GPCRs. Although a model to predict how signalling is produced via homo- or hetero-oligomerization is lacking, functional data show that receptor oligomers exist to produce a variety of effects in neurons in response to a single neurotransmitter.
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Affiliation(s)
- Rafael Franco
- Molecular Neurobiology Unit, Institut d'Investigacions Biomèdiques August Pi i Sunyer, Departament de Bioquímica i Biología Molecular, School of Biology, University of Barcelona, Spain.
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Brain receptor mosaics and their intramembrane receptor-receptor interactions: molecular integration in transmission and novel targets for drug development. J Acupunct Meridian Stud 2009; 2:1-25. [PMID: 20633470 DOI: 10.1016/s2005-2901(09)60011-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2008] [Accepted: 01/06/2009] [Indexed: 11/21/2022] Open
Abstract
The concept of intramembrane receptor-receptor interactions and evidence for their existence was introduced by Agnati and Fuxe in 1980/81 suggesting the existence of heteromerization of receptors. In 1982, they proposed the existence of aggregates of multiple receptors in the plasma membrane and coined the term receptor mosaics (RM). In this way, cell signaling becomes a branched process beginning at the level of receptor recognition at the plasma membrane where receptors can directly modify the ligand recognition and signaling capacity of the receptors within a RM. Receptor-receptor interactions in RM are classified as operating either with classical cooperativity, when consisting of homomers or heteromers of similar receptor subtypes having the same transmitter, or non-classical cooperativity, when consisting of heteromers. It has been shown that information processing within a RM depends not only on its receptor composition, but also on the topology and the order of receptor activation determined by the concentrations of the ligands and the receptor properties. The general function of RM has also been demonstrated to depend on allosteric regulators (e.g., homocysteine) of the receptor subtypes present. RM as integrative nodes for receptor-receptor interactions in conjunction with membrane associated proteins may form horizontal molecular networks in the plasma membrane coordinating the activity of multiple effector systems modulating the excitability and gene expression of the cells. The key role of electrostatic epitope-epitope interactions will be discussed for the formation of the RM. These interactions probably represent a general molecular mechanism for receptor-receptor interactions and, without a doubt, indicate a role for phosphorylation-dephosphorylation events in these interactions. The novel therapeutic aspects given by the RMs will be discussed in the frame of molecular neurology and psychiatry and combined drug therapy appears as the future way to go.
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Brea J, Castro M, Giraldo J, López-Giménez JF, Padín JF, Quintián F, Cadavid MI, Vilaró MT, Mengod G, Berg KA, Clarke WP, Vilardaga JP, Milligan G, Loza MI. Evidence for distinct antagonist-revealed functional states of 5-hydroxytryptamine(2A) receptor homodimers. Mol Pharmacol 2009; 75:1380-91. [PMID: 19279328 DOI: 10.1124/mol.108.054395] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The serotonin (5-hydroxytryptamine; 5-HT) 2A receptor is a cell surface class A G protein-coupled receptor that regulates a multitude of physiological functions of the body and is a target for antipsychotic drugs. Here we found by means of fluorescence resonance energy transfer and immunoprecipitation studies that the 5-HT(2A)-receptor homodimerized in live cells, which we linked with its antagonist-dependent fingerprint in both binding and receptor signaling. Some antagonists, like the atypical antipsychotics clozapine and risperidone, differentiate themselves from others, like the typical antipsychotic haloperidol, antagonizing these 5-HT(2A) receptor-mediated functions in a pathway-specific manner, explained here by a new model of multiple active interconvertible conformations at dimeric receptors.
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Affiliation(s)
- José Brea
- Departamento de Farmacología, Instituto de Farmacia Industrial, Universidad de Santiago de Compostela, Spain
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44
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Abstract
Extracellular adenosine is produced in a coordinated manner from cells following cellular challenge or tissue injury. Once produced, it serves as an autocrine- and paracrine-signaling molecule through its interactions with seven-membrane-spanning G-protein-coupled adenosine receptors. These signaling pathways have widespread physiological and pathophysiological functions. Immune cells express adenosine receptors and respond to adenosine or adenosine agonists in diverse manners. Extensive in vitro and in vivo studies have identified potent anti-inflammatory functions for all of the adenosine receptors on many different inflammatory cells and in various inflammatory disease processes. In addition, specific proinflammatory functions have also been ascribed to adenosine receptor activation. The potent effects of adenosine signaling on the regulation of inflammation suggest that targeting specific adenosine receptor activation or inactivation using selective agonists and antagonists could have important therapeutic implications in numerous diseases. This review is designed to summarize the current status of adenosine receptor signaling in various inflammatory cells and in models of inflammation, with an emphasis on the advancement of adenosine-based therapeutics to treat inflammatory disorders.
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Affiliation(s)
- Michael R Blackburn
- Department of Biochemistry and Molecular Biology, The University of Texas-Houston Medical School, Houston, TX 77030, USA.
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45
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Abstract
Adenosine acts as a cytoprotective modulator in response to stress to an organ or tissue. Although short-lived in the circulation, it can activate four subtypes of G protein-coupled adenosine receptors (ARs): A(1), A(2A), A(2B), and A(3). The alkylxanthines caffeine and theophylline are the prototypical antagonists of ARs, and their stimulant actions occur primarily through this mechanism. For each of the four AR subtypes, selective agonists and antagonists have been introduced and used to develop new therapeutic drug concepts. ARs are notable among the GPCR family in the number and variety of agonist therapeutic candidates that have been proposed. The selective and potent synthetic AR agonists, which are typically much longer lasting in the body than adenosine, have potential therapeutic applications based on their anti-inflammatory (A(2A) and A(3)), cardioprotective (preconditioning by A(1) and A(3) and postconditioning by A(2B)), cerebroprotective (A(1) and A(3)), and antinociceptive (A(1)) properties. Potent and selective AR antagonists display therapeutic potential as kidney protective (A(1)), antifibrotic (A(2A)), neuroprotective (A(2A)), and antiglaucoma (A(3)) agents. AR agonists for cardiac imaging and positron-emitting AR antagonists are in development for diagnostic applications. Allosteric modulators of A(1) and A(3) ARs have been described. In addition to the use of selective agonists/antagonists as pharmacological tools, mouse strains in which an AR has been genetically deleted have aided in developing novel drug concepts based on the modulation of ARs.
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Affiliation(s)
- Kenneth A Jacobson
- Molecular Recognition Section, Laboratory of Biooorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0810, USA.
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46
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Neurotransmitter receptor heteromers in neurodegenerative diseases and neural plasticity. J Neural Transm (Vienna) 2008; 116:983-7. [PMID: 19002553 DOI: 10.1007/s00702-008-0148-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2008] [Accepted: 10/20/2008] [Indexed: 10/21/2022]
Abstract
Metabotropic receptors for neurotransmitters on the plasma membrane of neurons are forming homo- hetero- dimers and even homo- or hetero-oligomers. Neurotransmission has been studied assuming that these G-protein-coupled receptors were monomers. Then, on considering receptor dimers, we are entering a new era for the understanding how neurotransmitter receptors decode signals originating at the nervous system. At the moment it is becoming clear that receptor homo and hetero-oligomers provide signaling diversity, help to understand synaptic plasticity and open new therapeutic potential as targets for neurodegenerative and neuropsychiatric diseases.
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Gracia E, Cortés A, Meana JJ, García-Sevilla J, Herhsfield MS, Canela EI, Mallol J, Lluís C, Franco R, Casadó V. Human adenosine deaminase as an allosteric modulator of human A(1) adenosine receptor: abolishment of negative cooperativity for [H](R)-pia binding to the caudate nucleus. J Neurochem 2008; 107:161-70. [PMID: 18680557 DOI: 10.1111/j.1471-4159.2008.05602.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
It has been shown that adenosine deaminase (ADA; EC 3.5.4.4) behaves as an ecto-enzyme anchored to membrane proteins, among them A(1) adenosine receptors (A(1)Rs). Bovine ADA interacts with A(1)Rs from many species and regulates agonists binding to receptors in an activity-independent form. However, it was not known whether human ADA exerted any effect on the agonist binding to human A(1)Rs, because of both technical difficulties in obtaining pure human ADA and tissues containing human A(1)Rs. In this study, human ADA was purified to homogeneity. Taking in consideration that A(1)Rs form homodimers and taking advantage of a new procedure to fit binding data to receptors dimers, which allows to calculate ligand dissociation constants and the degree of cooperativity between the two subunits in the dimer, here it is demonstrated that human ADA markedly enhances the agonist and antagonist affinity and abolishes the negative cooperativity on agonist binding to human striatal A(1)Rs. ADA also increases the ability of the agonist to decrease the forskolin-induced cAMP levels. The results show that human ADA, apart from reducing the adenosine concentration and thus preventing A(1)R desensitization, binds to A(1)R behaving as an allosteric effector that markedly enhances agonist affinity and increases receptor functionality. The physiological role of the interaction is to make receptors more sensitive to adenosine. This powerful regulation has important implications for the physiology and pharmacology of neuronal A(1)Rs.
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Affiliation(s)
- Eduard Gracia
- Institut d'Investigacions Biomèdiques August Pi i Sunyer, Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), University of Barcelona, Spain.
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Harikumar KG, Happs RM, Miller LJ. Dimerization in the absence of higher-order oligomerization of the G protein-coupled secretin receptor. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2008; 1778:2555-63. [PMID: 18680717 DOI: 10.1016/j.bbamem.2008.07.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2008] [Revised: 07/07/2008] [Accepted: 07/10/2008] [Indexed: 01/14/2023]
Abstract
Oligomerization of G protein-coupled receptors has been proposed to affect receptor function and regulation; however, little is known about the molecular nature of such complexes. We previously utilized bioluminescence resonance energy transfer (BRET) to demonstrate that the prototypic Family B secretin receptor can form oligomers. We now explore the order of oligomerization present utilizing unique bimolecular fluorescence complementation and energy transfer techniques. The non-fluorescent carboxyl-terminal and amino-terminal halves of yellow fluorescent protein (YFP) were fused to the carboxyl terminus of the secretin receptor. These constructs bound secretin normally and signaled in response to secretin like wild type receptor. When co-expressed on COS cells, these constructs physically interacted to yield typical YFP fluorescence in biosynthetic compartments and at the plasma membrane, reflecting receptor homo-dimerization. However, the addition of another potential partner in form of Rlu- or CFP-tagged secretin receptor yielded no significant BRET or FRET signal, respectively, under conditions in which intact YFP-tagged secretin receptor yielded such a signal. Absence of higher-order receptor oligomers was further confirmed using saturation BRET techniques. Absence of significant resonance transfer to the secretin receptor homo-dimer was true for carboxyl-terminally-tagged secretin receptor, as well as for receptor incorporating the transfer partner into each of the three distinct intracellular loop domains. These results suggest that the secretin receptor can exist only as a structurally-specific homo-dimer, without being present as higher-order oligomers.
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Affiliation(s)
- Kaleeckal G Harikumar
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, AZ 85259, USA
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49
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Franco R, Casadó V, Cortés A, Pérez-Capote K, Mallol J, Canela E, Ferré S, Lluis C. Novel pharmacological targets based on receptor heteromers. ACTA ACUST UNITED AC 2008; 58:475-82. [PMID: 18620000 DOI: 10.1016/j.brainresrev.2008.06.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2008] [Revised: 06/11/2008] [Accepted: 06/12/2008] [Indexed: 12/24/2022]
Abstract
Studies performed in the last 10 years have provided solid evidence indicating that G-protein-coupled receptors are expressed on the plasma membrane as homo and heterodimers. The first consequence of this fact is that homo and heterodimers are the true targets of natural (hormones, neurotransmitters) and synthetic drugs. Furthermore a given receptor in a heteromer may display a different functional and/or pharmacological profile than the same receptor characterized as monomer or as homodimer. Recent evidence indicates that receptor heteromers are sensors that lead to a fine-tuning in neurotransmission or hormone regulation; mainly this is achieved by a modification of the signaling pathways activated via a given receptor when it is forming a given heteromer. Quite often antagonists display variable affinities when a given receptor is expressed with different heteromeric partners. This fact should be taken into account in the development of new drugs. Finally it should be pointed out that radioligand binding data has to be analyzed by a model that considers receptors as dimers and not as monomers. This model provides a novel approach to characterize drugs interacting with the orthosteric center (agonists/antagonists) or with allosteric centers (allosteric regulators).
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Affiliation(s)
- Rafael Franco
- Institut d'Investigació Biomèdica August Pi i Sunyer (IDIBAPS), Department of Biochemistry and Molecular Biology, University of Barcelona, Barcelona, Spain.
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50
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Giraldo J. On the fitting of binding data when receptor dimerization is suspected. Br J Pharmacol 2008; 155:17-23. [PMID: 18536745 DOI: 10.1038/bjp.2008.234] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Mechanistic and empirical modelling are compared in context of dimeric receptors. In particular, the supposed advantages of the two-state dimer model for fitting of binding data with respect to classical approaches such as the two-independent sites model are investigated. The two models are revisited from both the mechanistic and empirical point of views. The problem of overparameterized models and the benefits of the concurrent use of mechanistic and empirical models for mechanism analysis are discussed. The pros and cons of mathematical models are examined with special emphasis given to the interpretation of the connection between the shapes of the curves and receptor cooperativity. It is shown that a given pharmacological phenotype (curve shape) can be obtained from different receptor genotypes (as, for instance, non-interconvertible monomeric receptor species, receptor-G protein interactions and dimeric receptors), though values of the Hill coefficient greater than one are indicative of receptor oligomerization. The existence of a relationship between the recently defined dimer cooperativity index and the more familiar Hill coefficient is proven.
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Affiliation(s)
- J Giraldo
- Grup Biomatemàtic de Recerca, Institut de Neurociències and Unitat de Bioestadística, Universitat Autònoma de Barcelona, Bellaterra, Spain.
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