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Echeazarra L, García Del Caño G, Barrondo S, González-Burguera I, Saumell-Esnaola M, Aretxabala X, López de Jesús M, Borrega-Román L, Mato S, Ledent C, Matute C, Goicolea MA, Sallés J. Fit-for-purpose based testing and validation of antibodies to amino- and carboxy-terminal domains of cannabinoid receptor 1. Histochem Cell Biol 2021; 156:479-502. [PMID: 34453219 PMCID: PMC8604870 DOI: 10.1007/s00418-021-02025-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/17/2021] [Indexed: 12/16/2022]
Abstract
Specific and selective anti-CB1 antibodies are among the most powerful research tools to unravel the complex biological processes mediated by the CB1 receptor in both physiological and pathological conditions. However, low performance of antibodies remains a major source of inconsistency between results from different laboratories. Using a variety of techniques, including some of the most commonly accepted ones for antibody specificity testing, we identified three of five commercial antibodies against different regions of CB1 receptor as the best choice for specific end-use purposes. Specifically, an antibody against a long fragment of the extracellular amino tail of CB1 receptor (but not one against a short sequence of the extreme amino-terminus) detected strong surface staining when applied to live cells, whereas two different antibodies against an identical fragment of the extreme carboxy-terminus of CB1 receptor (but not one against an upstream peptide) showed acceptable performance on all platforms, although they behaved differently in immunohistochemical assays depending on the tissue fixation procedure used and showed different specificity in Western blot assays, which made each of them particularly suitable for one of those techniques. Our results provide a framework to interpret past and future results derived from the use of different anti-CB1 antibodies in the context of current knowledge about the CB1 receptor at the molecular level, and highlight the need for an adequate validation for specific purposes, not only before antibodies are placed on the market, but also before the decision to discontinue them is made.
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Affiliation(s)
- Leyre Echeazarra
- Departament of Physiology, Faculty of Pharmacy, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Spain.,Bioaraba, Dispositivos Móviles para el Control de Enfermedades Crónicas, 01008, Vitoria-Gasteiz, Spain
| | - Gontzal García Del Caño
- Department of Neurosciences, Faculty of Pharmacy, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Spain. .,Bioaraba, Neurofarmacología Celular y Molecular, 01008, Vitoria-Gasteiz, Spain.
| | - Sergio Barrondo
- Department of Pharmacology, Faculty of Pharmacy, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Spain.,Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), 28029, Madrid, Spain.,Bioaraba, Neurofarmacología Celular y Molecular, 01008, Vitoria-Gasteiz, Spain
| | - Imanol González-Burguera
- Department of Neurosciences, Faculty of Pharmacy, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Spain.,Bioaraba, Neurofarmacología Celular y Molecular, 01008, Vitoria-Gasteiz, Spain
| | - Miquel Saumell-Esnaola
- Department of Pharmacology, Faculty of Pharmacy, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Spain.,Bioaraba, Neurofarmacología Celular y Molecular, 01008, Vitoria-Gasteiz, Spain
| | - Xabier Aretxabala
- Department of Neurosciences, Faculty of Pharmacy, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Spain
| | - Maider López de Jesús
- Department of Pharmacology, Faculty of Pharmacy, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Spain.,Bioaraba, Neurofarmacología Celular y Molecular, 01008, Vitoria-Gasteiz, Spain
| | - Leire Borrega-Román
- Department of Pharmacology, Faculty of Pharmacy, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Spain.,Bioaraba, Neurofarmacología Celular y Molecular, 01008, Vitoria-Gasteiz, Spain
| | - Susana Mato
- Department of Neurosciences, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Leioa, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Achucarro Basque Center for Neuroscience, Leioa, Spain.,Multiple Sclerosis and Other Demyelinating Diseases Unit, Biocruces Bizkaia, Barakaldo, Spain
| | | | - Carlos Matute
- Department of Neurosciences, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Leioa, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Achucarro Basque Center for Neuroscience, Leioa, Spain
| | - María Aranzazu Goicolea
- Department of Analytical Chemistry, Faculty of Pharmacy, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Spain
| | - Joan Sallés
- Department of Pharmacology, Faculty of Pharmacy, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Spain. .,Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), 28029, Madrid, Spain. .,Bioaraba, Neurofarmacología Celular y Molecular, 01008, Vitoria-Gasteiz, Spain.
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2
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ADORA2A variation and adenosine A 1 receptor availability in the human brain with a focus on anxiety-related brain regions: modulation by ADORA1 variation. Transl Psychiatry 2020; 10:406. [PMID: 33235193 PMCID: PMC7686488 DOI: 10.1038/s41398-020-01085-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 10/11/2020] [Accepted: 10/26/2020] [Indexed: 02/06/2023] Open
Abstract
Adenosine, its interacting A1 and A2A receptors, and particularly the variant rs5751876 in the A2A gene ADORA2A have been shown to modulate anxiety, arousal, and sleep. In a pilot positron emission tomography (PET) study in healthy male subjects, we suggested an effect of rs5751876 on in vivo brain A1 receptor (A1AR) availability. As female sex and adenosinergic/dopaminergic interaction partners might have an impact on this rs5751876 effect on A1AR availability, we aimed to (1) further investigate the pilot male-based findings in an independent, newly recruited cohort including women and (2) analyze potential modulation of this rs5751876 effect by additional adenosinergic/dopaminergic gene variation. Healthy volunteers (32/11 males/females) underwent phenotypic characterization including self-reported sleep and A1AR-specific quantitative PET. Rs5751876 and 31 gene variants of adenosine A1, A2A, A2B, and A3 receptors, adenosine deaminase, and dopamine D2 receptor were genotyped. Multivariate analysis revealed an rs5751876 effect on A1AR availability (P = 0.047), post hoc confirmed in 30 of 31 brain regions (false discovery rate (FDR) corrected P values < 0.05), but statistically stronger in anxiety-related regions (e.g., amygdala, hippocampus). Additional effects of ADORA1 rs1874142 were identified; under its influence rs5751876 and rs5751876 × sleep had strengthened effects on A1AR availability (Pboth < 0.02; post hoc FDR-corrected Ps < 0.05 for 29/30 regions, respectively). Our results support the relationship between rs5751876 and A1AR availability. Additional impact of rs1874142, together with rs5751876 and sleep, might be involved in regulating arousal and thus the development of mental disorders like anxiety disorders. The interplay of further detected suggestive ADORA2A × DRD2 interaction, however, necessitates larger future samples more comparable to magnetic resonance imaging (MRI)-based samples.
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Moreno E, Cavic M, Krivokuca A, Canela EI. The Interplay between Cancer Biology and the Endocannabinoid System-Significance for Cancer Risk, Prognosis and Response to Treatment. Cancers (Basel) 2020; 12:cancers12113275. [PMID: 33167409 PMCID: PMC7694406 DOI: 10.3390/cancers12113275] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 11/02/2020] [Accepted: 11/02/2020] [Indexed: 12/18/2022] Open
Abstract
The various components of the endocannabinoid system (ECS), such as the cannabinoid receptors (CBRs), cannabinoid ligands, and the signalling network behind it, are implicated in several tumour-related states, both as favourable and unfavourable factors. This review analyses the ECS's complex involvement in the susceptibility to cancer, prognosis, and response to treatment, focusing on its relationship with cancer biology in selected solid cancers (breast, gastrointestinal, gynaecological, prostate cancer, thoracic, thyroid, CNS tumours, and melanoma). Changes in the expression and activation of CBRs, as well as their ability to form distinct functional heteromers affect the cell's tumourigenic potential and their signalling properties, leading to pharmacologically different outcomes. Thus, the same ECS component can exert both protective and pathogenic effects in different tumour subtypes, which are often pathologically driven by different biological factors. The use of endogenous and exogenous cannabinoids as anti-cancer agents, and the range of effects they might induce (cell death, regulation of angiogenesis, and invasion or anticancer immunity), depend in great deal on the tumour type and the specific ECS component that they target. Although an attractive target, the use of ECS components in anti-cancer treatment is still interlinked with many legal and ethical issues that need to be considered.
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Affiliation(s)
- Estefanía Moreno
- Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
- Institute of Biomedicine of the University of Barcelona (IBUB), 08028 Barcelona, Spain
- Correspondence: (E.M.); (E.I.C.)
| | - Milena Cavic
- Department of Experimental Oncology, Institute for Oncology and Radiology of Serbia, Pasterova 14, 11000 Belgrade, Serbia; (M.C.); (A.K.)
| | - Ana Krivokuca
- Department of Experimental Oncology, Institute for Oncology and Radiology of Serbia, Pasterova 14, 11000 Belgrade, Serbia; (M.C.); (A.K.)
| | - Enric I. Canela
- Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
- Institute of Biomedicine of the University of Barcelona (IBUB), 08028 Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28031, Madrid, Spain
- Correspondence: (E.M.); (E.I.C.)
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4
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Ventura ALM, Dos Santos-Rodrigues A, Mitchell CH, Faillace MP. Purinergic signaling in the retina: From development to disease. Brain Res Bull 2018; 151:92-108. [PMID: 30458250 DOI: 10.1016/j.brainresbull.2018.10.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 09/14/2018] [Accepted: 10/23/2018] [Indexed: 02/07/2023]
Abstract
Retinal injuries and diseases are major causes of human disability involving vision impairment by the progressive and permanent loss of retinal neurons. During development, assembly of this tissue entails a successive and overlapping, signal-regulated engagement of complex events that include proliferation of progenitors, neurogenesis, cell death, neurochemical differentiation and synaptogenesis. During retinal damage, several of these events are re-activated with both protective and detrimental consequences. Purines and pyrimidines, along with their metabolites are emerging as important molecules regulating both retinal development and the tissue's responses to damage. The present review provides an overview of the purinergic signaling in the developing and injured retina. Recent findings on the presence of vesicular and channel-mediated ATP release by retinal and retinal pigment epithelial cells, adenosine synthesis and release, expression of receptors and intracellular signaling pathways activated by purinergic signaling in retinal cells are reported. The pathways by which purinergic receptors modulate retinal cell proliferation, migration and death of retinal cells during development and injury are summarized. The contribution of nucleotides to the self-repair of the injured zebrafish retina is also discussed.
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Affiliation(s)
- Ana Lucia Marques Ventura
- Department of Neurobiology, Neuroscience Program, Fluminense Federal University, Niterói, RJ, Brazil.
| | | | - Claire H Mitchell
- Department of Anatomy and Cell Biology, Ophthalmology, and Physiology, University of Pennsylvania, Philadelphia, PA 19104, United States.
| | - Maria Paula Faillace
- Instituto de Fisiología y Biofísica Prof. Bernardo Houssay (IFIBIO-Houssay), Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina; Departamento de Fisiología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.
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5
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Odagaki Y, Kinoshita M, Ota T, Meana JJ, Callado LF, Matsuoka I, García-Sevilla JA. Functional coupling between adenosine A 1 receptors and G-proteins in rat and postmortem human brain membranes determined with conventional guanosine-5'-O-(3-[ 35S]thio)triphosphate ([ 35S]GTPγS) binding or [ 35S]GTPγS/immunoprecipitation assay. Purinergic Signal 2018; 14:177-190. [PMID: 29492786 DOI: 10.1007/s11302-018-9603-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 02/15/2018] [Indexed: 11/27/2022] Open
Abstract
Adenosine signaling plays a complex role in multiple physiological processes in the brain, and its dysfunction has been implicated in pathophysiology of neuropsychiatric diseases such as schizophrenia and affective disorders. In the present study, the coupling between adenosine A1 receptor and G-protein was assessed by means of two [35S]GTPγS binding assays, i.e., conventional filtration method and [35S]GTPγS binding/immunoprecipitation in rat and human brain membranes. The latter method provides information about adenosine A1 receptor-mediated Gαi-3 activation in rat as well as human brain membranes. On the other hand, adenosine-stimulated [35S]GTPγS binding determined with conventional assay derives from functional activation of Gαi/o proteins (not restricted only to Gαi-3) coupled to adenosine A1 receptors. The determination of adenosine concentrations in the samples used in the present study indicates the possibility that the assay mixture under our experimental conditions contains residual endogenous adenosine at nanomolar concentrations, which was also suggested by the results on the effects of adenosine receptor antagonists on basal [35S]GTPγS binding level. The effects of adenosine deaminase (ADA) on basal binding also support the presence of adenosine. Nevertheless, the varied patterns of ADA discouraged us from adding ADA into assay medium routinely. The concentration-dependent increases elicited by adenosine were determined in 40 subjects without any neuropsychiatric disorders. The increases in %Emax values determined by conventional assay according to aging and postmortem delay should be taken into account in future studies focusing on the effects of psychiatric disorders on adenosine A1 receptor/G-protein interaction in postmortem human brain tissue.
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Affiliation(s)
- Yuji Odagaki
- Department of Psychiatry, Faculty of Medicine, Saitama Medical University, 38 Morohongo, Moroyama-machi, Iruma-gun, Saitama, 350-0495, Japan.
| | - Masakazu Kinoshita
- Department of Psychiatry, Faculty of Medicine, Saitama Medical University, 38 Morohongo, Moroyama-machi, Iruma-gun, Saitama, 350-0495, Japan
| | - Toshio Ota
- Department of Psychiatry, Faculty of Medicine, Saitama Medical University, 38 Morohongo, Moroyama-machi, Iruma-gun, Saitama, 350-0495, Japan
| | - J Javier Meana
- Department of Pharmacology, University of the Basque Country, UPV/EHU, 48940, Leioa, Bizkaia, Spain.,Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, Leioa, Bizkaia, Spain
| | - Luis F Callado
- Department of Pharmacology, University of the Basque Country, UPV/EHU, 48940, Leioa, Bizkaia, Spain.,Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, Leioa, Bizkaia, Spain
| | - Isao Matsuoka
- Laboratory of Pharmacology, Faculty of Pharmacy, Takasaki University of Health and Welfare, Takasaki-shi, Gunma, 370-0033, Japan
| | - Jesús A García-Sevilla
- Laboratory of Neuropharmacology, IUNICS/IdISPa, University of the Balearic Islands (UIB), Palma, Spain
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6
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Madeira MH, Elvas F, Boia R, Gonçalves FQ, Cunha RA, Ambrósio AF, Santiago AR. Adenosine A2AR blockade prevents neuroinflammation-induced death of retinal ganglion cells caused by elevated pressure. J Neuroinflammation 2015; 12:115. [PMID: 26054642 PMCID: PMC4465153 DOI: 10.1186/s12974-015-0333-5] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 05/27/2015] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Elevated intraocular pressure (IOP) is a major risk factor for glaucoma, a degenerative disease characterized by the loss of retinal ganglion cells (RGCs). There is clinical and experimental evidence that neuroinflammation is involved in the pathogenesis of glaucoma. Since the blockade of adenosine A2A receptor (A2AR) confers robust neuroprotection and controls microglia reactivity in the brain, we now investigated the ability of A2AR blockade to control the reactivity of microglia and neuroinflammation as well as RGC loss in retinal organotypic cultures exposed to elevated hydrostatic pressure (EHP) or lipopolysaccharide (LPS). METHODS Retinal organotypic cultures were either incubated with LPS (3 μg/mL), to elicit a pro-inflammatory response, or exposed to EHP (+70 mmHg), to mimic increased IOP, for 4 or 24 h, in the presence or absence of the A2AR antagonist SCH 58261 (50 nM). A2AR expression, microglial reactivity and neuroinflammatory response were evaluated by immunohistochemistry, quantitative PCR (qPCR) and enzyme-linked immunosorbent assay (ELISA). RGC loss was assessed by immunohistochemistry. In order to investigate the contribution of pro-inflammatory mediators to RGC loss, the organotypic retinal cultures were incubated with rabbit anti-tumour necrosis factor (TNF) (2 μg/mL) and goat anti-interleukin-1β (IL-1β) (1 μg/mL) antibodies. RESULTS We report that the A2AR antagonist (SCH 58261) prevented microglia reactivity, increase in pro-inflammatory mediators as well as RGC loss upon exposure to either LPS or EHP. Additionally, neutralization of TNF and IL-1β prevented RGC loss induced by LPS or EHP. CONCLUSIONS This work demonstrates that A2AR blockade confers neuroprotection to RGCs by controlling microglia-mediated retinal neuroinflammation and prompts the hypothesis that A2AR antagonists may be a novel therapeutic option to manage glaucomatous disorders.
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Affiliation(s)
- Maria H Madeira
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548, Coimbra, Portugal. .,CNC.IBILI, University of Coimbra, 3004-517, Coimbra, Portugal.
| | - Filipe Elvas
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548, Coimbra, Portugal.
| | - Raquel Boia
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548, Coimbra, Portugal. .,CNC.IBILI, University of Coimbra, 3004-517, Coimbra, Portugal.
| | - Francisco Q Gonçalves
- CNC.IBILI, University of Coimbra, 3004-517, Coimbra, Portugal. .,CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517, Coimbra, Portugal.
| | - Rodrigo A Cunha
- CNC.IBILI, University of Coimbra, 3004-517, Coimbra, Portugal. .,CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517, Coimbra, Portugal. .,Faculty of Medicine, University of Coimbra, 3000-548, Coimbra, Portugal.
| | - António Francisco Ambrósio
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548, Coimbra, Portugal. .,CNC.IBILI, University of Coimbra, 3004-517, Coimbra, Portugal. .,Association for Innovation and Biomedical Research on Light (AIBILI), 3000-548, Coimbra, Portugal.
| | - Ana Raquel Santiago
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3004-548, Coimbra, Portugal. .,CNC.IBILI, University of Coimbra, 3004-517, Coimbra, Portugal. .,Association for Innovation and Biomedical Research on Light (AIBILI), 3000-548, Coimbra, Portugal. .,Faculty of Medicine, University of Coimbra, 3000-548, Coimbra, Portugal. .,IBILI, Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, 3004-548, Coimbra, Portugal.
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7
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Hohoff C, Garibotto V, Elmenhorst D, Baffa A, Kroll T, Hoffmann A, Schwarte K, Zhang W, Arolt V, Deckert J, Bauer A. Association of adenosine receptor gene polymorphisms and in vivo adenosine A1 receptor binding in the human brain. Neuropsychopharmacology 2014; 39:2989-99. [PMID: 24943643 PMCID: PMC4229568 DOI: 10.1038/npp.2014.150] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 05/13/2014] [Accepted: 05/27/2014] [Indexed: 11/09/2022]
Abstract
Adenosine A1 receptors (A1ARs) and the interacting adenosine A2A receptors are implicated in neurological and psychiatric disorders. Variants within the corresponding genes ADORA1 and ADORA2A were shown associated with pathophysiologic alterations, particularly increased anxiety. It is unknown so far, if these variants might modulate the A1AR distribution and availability in different brain regions. In this pilot study, the influence of ADORA1 and ADORA2A variants on in vivo A1AR binding was assessed with the A1AR-selective positron emission tomography (PET) radioligand [(18)F]CPFPX in brains of healthy humans. Twenty-eight normal control subjects underwent PET procedures to calculate the binding potential BPND of [(18)F]CPFPX in cerebral regions and to assess ADORA1 and ADORA2A single nucleotide polymorphism (SNP) effects on regional BPND data. Our results revealed SNPs of both genes associated with [(18)F]CPFPX binding to the A1AR. The strongest effects that withstood even Bonferroni correction of multiple SNP testing were found in non-smoking subjects (N=22) for ADORA2A SNPs rs2236624 and rs5751876 (corr. Pall<0.05). SNP alleles previously identified at risk for increased anxiety like the rs5751876 T-allele corresponded to consistently higher A1AR availability in all brain regions. Our data indicate for the first time that variation of A1AR availability was associated with ADORA SNPs. The finding of increased A1AR availability in regions of the fear network, particularly in ADORA2A risk allele carriers, strongly warrants evaluation and replication in further studies including individuals with increased anxiety.
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Affiliation(s)
- Christa Hohoff
- Department of Psychiatry and Psychotherapy, University of Münster, Münster, Germany,Department of Psychiatry and Psychotherapy,, University of Münster, Albert-Schweitzer-Campus 1, A9, 48149 Münster, Germany, Phone: +4925 1835 7122; Fax: +4925 1835 7123, E-mail:
| | - Valentina Garibotto
- Institute of Neuroscience and Medicine (INM-2), Forschungszentrum Jülich, Jülich, Germany
| | - David Elmenhorst
- Institute of Neuroscience and Medicine (INM-2), Forschungszentrum Jülich, Jülich, Germany
| | - Anna Baffa
- Department of Psychiatry and Psychotherapy, University of Münster, Münster, Germany
| | - Tina Kroll
- Institute of Neuroscience and Medicine (INM-2), Forschungszentrum Jülich, Jülich, Germany
| | - Alana Hoffmann
- Department of Psychiatry and Psychotherapy, University of Münster, Münster, Germany
| | - Kathrin Schwarte
- Department of Psychiatry and Psychotherapy, University of Münster, Münster, Germany
| | - Weiqi Zhang
- Department of Psychiatry and Psychotherapy, University of Münster, Münster, Germany
| | - Volker Arolt
- Department of Psychiatry and Psychotherapy, University of Münster, Münster, Germany
| | - Jürgen Deckert
- Department of Psychiatry, Psychosomatics and Psychotherapy, University of Würzburg, Würzburg, Germany
| | - Andreas Bauer
- Institute of Neuroscience and Medicine (INM-2), Forschungszentrum Jülich, Jülich, Germany
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Hill SJ, May LT, Kellam B, Woolard J. Allosteric interactions at adenosine A(1) and A(3) receptors: new insights into the role of small molecules and receptor dimerization. Br J Pharmacol 2014; 171:1102-13. [PMID: 24024783 DOI: 10.1111/bph.12345] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 07/09/2013] [Accepted: 07/12/2013] [Indexed: 12/22/2022] Open
Abstract
The purine nucleoside adenosine is present in all cells in tightly regulated concentrations. It is released under a variety of physiological and pathophysiological conditions to facilitate protection and regeneration of tissues. Adenosine acts via specific GPCRs to either stimulate cyclic AMP formation, as exemplified by Gs -protein-coupled adenosine receptors (A2A and A2B ), or inhibit AC activity, in the case of Gi/o -coupled adenosine receptors (A1 and A3 ). Recent advances in our understanding of GPCR structure have provided insights into the conformational changes that occur during receptor activation following binding of agonists to orthosteric (i.e. at the same binding site as an endogenous modulator) and allosteric regulators to allosteric sites (i.e. at a site that is topographically distinct from the endogenous modulator). Binding of drugs to allosteric sites may lead to changes in affinity or efficacy, and affords considerable potential for increased selectivity in new drug development. Herein, we provide an overview of the properties of selective allosteric regulators of the adenosine A1 and A3 receptors, focusing on the impact of receptor dimerization, mechanistic approaches to single-cell ligand-binding kinetics and the effects of A1 - and A3 -receptor allosteric modulators on in vivo pharmacology.
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Affiliation(s)
- Stephen J Hill
- Cell Signalling Research Group, School of Biomedical Sciences, Medical School, Queen's Medical Centre, University of Nottingham, Nottingham, UK
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9
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Smith NJ, Milligan G. Allostery at G protein-coupled receptor homo- and heteromers: uncharted pharmacological landscapes. Pharmacol Rev 2011; 62:701-25. [PMID: 21079041 DOI: 10.1124/pr.110.002667] [Citation(s) in RCA: 211] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
For many years seven transmembrane domain G protein-coupled receptors (GPCRs) were thought to exist and function exclusively as monomeric units. However, evidence both from native cells and heterologous expression systems has demonstrated that GPCRs can both traffic and signal within higher-order complexes. As for other protein-protein interactions, conformational changes in one polypeptide, including those resulting from binding of pharmacological ligands, have the capacity to alter the conformation and therefore the response of the interacting protein(s), a process known as allosterism. For GPCRs, allosterism across homo- or heteromers, whether dimers or higher-order oligomers, represents an additional topographical landscape that must now be considered pharmacologically. Such effects may offer the opportunity for novel therapeutic approaches. Allosterism at GPCR heteromers is particularly exciting in that it offers additional scope to provide receptor subtype selectivity and tissue specificity as well as fine-tuning of receptor signal strength. Herein, we introduce the concept of allosterism at both GPCR homomers and heteromers and discuss the various questions that must be addressed before significant advances can be made in drug discovery at these GPCR complexes.
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Affiliation(s)
- Nicola J Smith
- Molecular Pharmacology Laboratory,University Avenue, University of Glasgow, Glasgow, Scotland
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10
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Chandrasekera PC, McIntosh VJ, Cao FX, Lasley RD. Differential effects of adenosine A2a and A2b receptors on cardiac contractility. Am J Physiol Heart Circ Physiol 2010; 299:H2082-9. [PMID: 20935155 DOI: 10.1152/ajpheart.00511.2010] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The mammalian myocardium expresses four adenosine receptor (AR) subtypes: A(1)AR, A(2a)AR, A(2b)AR, and A(3)AR. The A(1)AR is well known for its profound antiadrenergic effects, but the roles of other AR subtypes in modulating contractility remain inconclusive. Thus, the objective of this study was to determine the direct and indirect effects of A(2a)AR and A(2b)AR on cardiac contractility. Experiments were conducted in paced, constant pressure-perfused isolated hearts from wild-type (WT), A(2a)AR knockout (KO), and A(2b)AR KO mice. The A(2a)AR agonist CGS-21680 did not alter basal contractility or β-adrenergic receptor agonist isoproterenol (Iso)-mediated positive inotropic responses, and Iso-induced effects were unaltered in A(2a)AR KO hearts. However, A(2a)AR gene ablation resulted in a potentiation of the antiadrenergic effects mediated by the A(1)AR agonist 2-chloro-N-cyclopentyladenosine. The nonselective AR agonist 5'-N-ethylcarboxamido adenosine and the selective A(2b)AR agonist BAY 60-6583 induced coronary flow-independent increases in contractility, but BAY 60-6583 did not alter Iso-induced contractile responses. The A(1)AR antiadrenergic effect was not potentiated in A(2b)AR KO hearts. The expression of all four AR subtypes in the heart and ventricular myocytes was confirmed using real-time quantitative PCR. Taken together, these results indicate that A(2a)AR does not increase cardiac contractility directly but indirectly alters contractility by modulating the A(1)AR antiadrenergic effect, whereas A(2b)AR exerts direct contractile effects but does not alter β-adrenergic or A(1)AR antiadrenergic effects. These results indicate that multiple ARs differentially modulate cardiac function.
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Affiliation(s)
- P Charukeshi Chandrasekera
- Department of Physiology and Cardiovascular Research Institute, Wayne State University School of Medicine, Detroit, Michigan, USA
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