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Quiroga DT, Narvaéz Pardo JA, Zubiría MG, Barrales B, Muñoz MC, Giovambattista A, Dominici FP. Acute In Vivo Administration of Compound 21 Stimulates Akt and ERK1/2 Phosphorylation in Mouse Heart and Adipose Tissue. Int J Mol Sci 2023; 24:16839. [PMID: 38069161 PMCID: PMC10706736 DOI: 10.3390/ijms242316839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 11/22/2023] [Accepted: 11/25/2023] [Indexed: 12/18/2023] Open
Abstract
The angiotensin II type 2 (AT2) receptor has a role in promoting insulin sensitivity. However, the mechanisms underlying the AT2 receptor-induced facilitation of insulin are still not completely understood. Therefore, we investigated whether acute in vivo administration of AT2 receptor agonist compound 21 (C21) could activate insulin signaling molecules in insulin-target tissues. We report that, in male C57BL/6 mice, an acute (5 min, 0.25 mg/kg; i.v.) injection of C21 induces the phosphorylation of Akt and ERK1/2 at activating residues (Ser473 and Thr202/Tyr204, respectively) in both epididymal white adipose tissue (WAT) and heart tissue. In WAT, the extent of phosphorylation (p) of Akt and ERK1/2 induced by C21 was approximately 65% of the level detected after a bolus injection of a dose of insulin known to induce maximal activation of the insulin receptor (IR). In the heart, C21 stimulated p-Akt to a lesser extent than in WAT and stimulated p-ERK1/2 to similar levels to those attained by insulin administration. C21 did not modify p-IR levels in either tissue. We conclude that in vivo injection of the AT2 receptor agonist C21 activates Akt and ERK1/2 through a mechanism that does not involve the IR, indicating the participation of these enzymes in AT2R-mediated signaling.
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Affiliation(s)
- Diego T. Quiroga
- Facultad de Farmacia y Bioquímica, Departamento de Química Biológica and IQUIFIB (UBA-CONICET), Universidad de Buenos Aires, Buenos Aires C1113AAD, Argentina
| | - Jorge A. Narvaéz Pardo
- Facultad de Farmacia y Bioquímica, Departamento de Química Biológica and IQUIFIB (UBA-CONICET), Universidad de Buenos Aires, Buenos Aires C1113AAD, Argentina
| | - María G. Zubiría
- Laboratorio de Neuroendocrinología, Instituto Multidisciplinario de Biología Celular (IMBICE), CICPBA-CONICET-UNLP), La Plata B1906APO, Argentina
| | - Benjamín Barrales
- Facultad de Farmacia y Bioquímica, Departamento de Química Biológica and IQUIFIB (UBA-CONICET), Universidad de Buenos Aires, Buenos Aires C1113AAD, Argentina
| | - Marina C. Muñoz
- Facultad de Farmacia y Bioquímica, Departamento de Química Biológica and IQUIFIB (UBA-CONICET), Universidad de Buenos Aires, Buenos Aires C1113AAD, Argentina
| | - Andrés Giovambattista
- Laboratorio de Neuroendocrinología, Instituto Multidisciplinario de Biología Celular (IMBICE), CICPBA-CONICET-UNLP), La Plata B1906APO, Argentina
| | - Fernando P. Dominici
- Facultad de Farmacia y Bioquímica, Departamento de Química Biológica and IQUIFIB (UBA-CONICET), Universidad de Buenos Aires, Buenos Aires C1113AAD, Argentina
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Colin M, Delaitre C, Foulquier S, Dupuis F. The AT 1/AT 2 Receptor Equilibrium Is a Cornerstone of the Regulation of the Renin Angiotensin System beyond the Cardiovascular System. Molecules 2023; 28:5481. [PMID: 37513355 PMCID: PMC10383525 DOI: 10.3390/molecules28145481] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 07/11/2023] [Accepted: 07/14/2023] [Indexed: 07/30/2023] Open
Abstract
The AT1 receptor has mainly been associated with the pathological effects of the renin-angiotensin system (RAS) (e.g., hypertension, heart and kidney diseases), and constitutes a major therapeutic target. In contrast, the AT2 receptor is presented as the protective arm of this RAS, and its targeting via specific agonists is mainly used to counteract the effects of the AT1 receptor. The discovery of a local RAS has highlighted the importance of the balance between AT1/AT2 receptors at the tissue level. Disruption of this balance is suggested to be detrimental. The fine tuning of this balance is not limited to the regulation of the level of expression of these two receptors. Other mechanisms still largely unexplored, such as S-nitrosation of the AT1 receptor, homo- and heterodimerization, and the use of AT1 receptor-biased agonists, may significantly contribute to and/or interfere with the settings of this AT1/AT2 equilibrium. This review will detail, through several examples (the brain, wound healing, and the cellular cycle), the importance of the functional balance between AT1 and AT2 receptors, and how new molecular pharmacological approaches may act on its regulation to open up new therapeutic perspectives.
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Affiliation(s)
- Mélissa Colin
- CITHEFOR, Université de Lorraine, F-54000 Nancy, France
- Department of Pharmacology and Toxicology, MHeNS-School for Mental Health and Neuroscience, Maastricht University, 6200 MD Maastricht, The Netherlands
| | | | - Sébastien Foulquier
- Department of Pharmacology and Toxicology, MHeNS-School for Mental Health and Neuroscience, Maastricht University, 6200 MD Maastricht, The Netherlands
- CARIM-School for Cardiovascular Diseases, Maastricht University, 6200 MD Maastricht, The Netherlands
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3
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Smith MT. Nonopioid analgesics discovery and the Valley of Death: EMA401 from concept to clinical trial. Pain 2022; 163:S15-S28. [PMID: 35984369 PMCID: PMC10578428 DOI: 10.1097/j.pain.0000000000002675] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Revised: 04/22/2022] [Accepted: 04/28/2022] [Indexed: 12/23/2022]
Affiliation(s)
- Maree T Smith
- Centre for Integrated Preclinical Drug Development, School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, Queensland, Australia
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4
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Steckelings UM, Widdop RE, Sturrock ED, Lubbe L, Hussain T, Kaschina E, Unger T, Hallberg A, Carey RM, Sumners C. The Angiotensin AT 2 Receptor: From a Binding Site to a Novel Therapeutic Target. Pharmacol Rev 2022; 74:1051-1135. [PMID: 36180112 PMCID: PMC9553111 DOI: 10.1124/pharmrev.120.000281] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 05/19/2022] [Accepted: 06/27/2022] [Indexed: 11/22/2022] Open
Abstract
Discovered more than 30 years ago, the angiotensin AT2 receptor (AT2R) has evolved from a binding site with unknown function to a firmly established major effector within the protective arm of the renin-angiotensin system (RAS) and a target for new drugs in development. The AT2R represents an endogenous protective mechanism that can be manipulated in the majority of preclinical models to alleviate lung, renal, cardiovascular, metabolic, cutaneous, and neural diseases as well as cancer. This article is a comprehensive review summarizing our current knowledge of the AT2R, from its discovery to its position within the RAS and its overall functions. This is followed by an in-depth look at the characteristics of the AT2R, including its structure, intracellular signaling, homo- and heterodimerization, and expression. AT2R-selective ligands, from endogenous peptides to synthetic peptides and nonpeptide molecules that are used as research tools, are discussed. Finally, we summarize the known physiological roles of the AT2R and its abundant protective effects in multiple experimental disease models and expound on AT2R ligands that are undergoing development for clinical use. The present review highlights the controversial aspects and gaps in our knowledge of this receptor and illuminates future perspectives for AT2R research. SIGNIFICANCE STATEMENT: The angiotensin AT2 receptor (AT2R) is now regarded as a fully functional and important component of the renin-angiotensin system, with the potential of exerting protective actions in a variety of diseases. This review provides an in-depth view of the AT2R, which has progressed from being an enigma to becoming a therapeutic target.
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Affiliation(s)
- U Muscha Steckelings
- Institute of Molecular Medicine, Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark (U.M.S.); Cardiovascular Disease Program, Biomedicine Discovery Institute, Department of Pharmacology, Monash University, Clayton, Victoria, Australia (R.E.W.); Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Republic of South Africa (E.D.S., L.L.); Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas (T.H.); Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Institute of Pharmacology, Cardiovascular-Metabolic-Renal (CMR) Research Center, DZHK (German Centre for Cardiovascular Research), Berlin, Germany (E.K.); CARIM - School for Cardiovascular Diseases, Maastricht University, The Netherlands (T.U.); Department of Medicinal Chemistry, Faculty of Pharmacy, Uppsala University, Uppsala, Sweden (A.H.); Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia (R.M.C.); and Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, Florida (C.S.)
| | - Robert E Widdop
- Institute of Molecular Medicine, Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark (U.M.S.); Cardiovascular Disease Program, Biomedicine Discovery Institute, Department of Pharmacology, Monash University, Clayton, Victoria, Australia (R.E.W.); Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Republic of South Africa (E.D.S., L.L.); Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas (T.H.); Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Institute of Pharmacology, Cardiovascular-Metabolic-Renal (CMR) Research Center, DZHK (German Centre for Cardiovascular Research), Berlin, Germany (E.K.); CARIM - School for Cardiovascular Diseases, Maastricht University, The Netherlands (T.U.); Department of Medicinal Chemistry, Faculty of Pharmacy, Uppsala University, Uppsala, Sweden (A.H.); Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia (R.M.C.); and Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, Florida (C.S.)
| | - Edward D Sturrock
- Institute of Molecular Medicine, Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark (U.M.S.); Cardiovascular Disease Program, Biomedicine Discovery Institute, Department of Pharmacology, Monash University, Clayton, Victoria, Australia (R.E.W.); Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Republic of South Africa (E.D.S., L.L.); Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas (T.H.); Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Institute of Pharmacology, Cardiovascular-Metabolic-Renal (CMR) Research Center, DZHK (German Centre for Cardiovascular Research), Berlin, Germany (E.K.); CARIM - School for Cardiovascular Diseases, Maastricht University, The Netherlands (T.U.); Department of Medicinal Chemistry, Faculty of Pharmacy, Uppsala University, Uppsala, Sweden (A.H.); Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia (R.M.C.); and Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, Florida (C.S.)
| | - Lizelle Lubbe
- Institute of Molecular Medicine, Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark (U.M.S.); Cardiovascular Disease Program, Biomedicine Discovery Institute, Department of Pharmacology, Monash University, Clayton, Victoria, Australia (R.E.W.); Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Republic of South Africa (E.D.S., L.L.); Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas (T.H.); Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Institute of Pharmacology, Cardiovascular-Metabolic-Renal (CMR) Research Center, DZHK (German Centre for Cardiovascular Research), Berlin, Germany (E.K.); CARIM - School for Cardiovascular Diseases, Maastricht University, The Netherlands (T.U.); Department of Medicinal Chemistry, Faculty of Pharmacy, Uppsala University, Uppsala, Sweden (A.H.); Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia (R.M.C.); and Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, Florida (C.S.)
| | - Tahir Hussain
- Institute of Molecular Medicine, Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark (U.M.S.); Cardiovascular Disease Program, Biomedicine Discovery Institute, Department of Pharmacology, Monash University, Clayton, Victoria, Australia (R.E.W.); Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Republic of South Africa (E.D.S., L.L.); Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas (T.H.); Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Institute of Pharmacology, Cardiovascular-Metabolic-Renal (CMR) Research Center, DZHK (German Centre for Cardiovascular Research), Berlin, Germany (E.K.); CARIM - School for Cardiovascular Diseases, Maastricht University, The Netherlands (T.U.); Department of Medicinal Chemistry, Faculty of Pharmacy, Uppsala University, Uppsala, Sweden (A.H.); Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia (R.M.C.); and Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, Florida (C.S.)
| | - Elena Kaschina
- Institute of Molecular Medicine, Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark (U.M.S.); Cardiovascular Disease Program, Biomedicine Discovery Institute, Department of Pharmacology, Monash University, Clayton, Victoria, Australia (R.E.W.); Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Republic of South Africa (E.D.S., L.L.); Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas (T.H.); Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Institute of Pharmacology, Cardiovascular-Metabolic-Renal (CMR) Research Center, DZHK (German Centre for Cardiovascular Research), Berlin, Germany (E.K.); CARIM - School for Cardiovascular Diseases, Maastricht University, The Netherlands (T.U.); Department of Medicinal Chemistry, Faculty of Pharmacy, Uppsala University, Uppsala, Sweden (A.H.); Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia (R.M.C.); and Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, Florida (C.S.)
| | - Thomas Unger
- Institute of Molecular Medicine, Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark (U.M.S.); Cardiovascular Disease Program, Biomedicine Discovery Institute, Department of Pharmacology, Monash University, Clayton, Victoria, Australia (R.E.W.); Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Republic of South Africa (E.D.S., L.L.); Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas (T.H.); Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Institute of Pharmacology, Cardiovascular-Metabolic-Renal (CMR) Research Center, DZHK (German Centre for Cardiovascular Research), Berlin, Germany (E.K.); CARIM - School for Cardiovascular Diseases, Maastricht University, The Netherlands (T.U.); Department of Medicinal Chemistry, Faculty of Pharmacy, Uppsala University, Uppsala, Sweden (A.H.); Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia (R.M.C.); and Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, Florida (C.S.)
| | - Anders Hallberg
- Institute of Molecular Medicine, Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark (U.M.S.); Cardiovascular Disease Program, Biomedicine Discovery Institute, Department of Pharmacology, Monash University, Clayton, Victoria, Australia (R.E.W.); Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Republic of South Africa (E.D.S., L.L.); Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas (T.H.); Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Institute of Pharmacology, Cardiovascular-Metabolic-Renal (CMR) Research Center, DZHK (German Centre for Cardiovascular Research), Berlin, Germany (E.K.); CARIM - School for Cardiovascular Diseases, Maastricht University, The Netherlands (T.U.); Department of Medicinal Chemistry, Faculty of Pharmacy, Uppsala University, Uppsala, Sweden (A.H.); Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia (R.M.C.); and Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, Florida (C.S.)
| | - Robert M Carey
- Institute of Molecular Medicine, Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark (U.M.S.); Cardiovascular Disease Program, Biomedicine Discovery Institute, Department of Pharmacology, Monash University, Clayton, Victoria, Australia (R.E.W.); Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Republic of South Africa (E.D.S., L.L.); Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas (T.H.); Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Institute of Pharmacology, Cardiovascular-Metabolic-Renal (CMR) Research Center, DZHK (German Centre for Cardiovascular Research), Berlin, Germany (E.K.); CARIM - School for Cardiovascular Diseases, Maastricht University, The Netherlands (T.U.); Department of Medicinal Chemistry, Faculty of Pharmacy, Uppsala University, Uppsala, Sweden (A.H.); Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia (R.M.C.); and Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, Florida (C.S.)
| | - Colin Sumners
- Institute of Molecular Medicine, Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark (U.M.S.); Cardiovascular Disease Program, Biomedicine Discovery Institute, Department of Pharmacology, Monash University, Clayton, Victoria, Australia (R.E.W.); Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Republic of South Africa (E.D.S., L.L.); Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas (T.H.); Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Institute of Pharmacology, Cardiovascular-Metabolic-Renal (CMR) Research Center, DZHK (German Centre for Cardiovascular Research), Berlin, Germany (E.K.); CARIM - School for Cardiovascular Diseases, Maastricht University, The Netherlands (T.U.); Department of Medicinal Chemistry, Faculty of Pharmacy, Uppsala University, Uppsala, Sweden (A.H.); Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia (R.M.C.); and Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, Florida (C.S.)
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5
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Singh KD, Karnik SS. Structural perspectives on the mechanism of signal activation, ligand selectivity and allosteric modulation in angiotensin receptors: IUPHAR Review 34. Br J Pharmacol 2022; 179:4461-4472. [PMID: 35318654 PMCID: PMC9398925 DOI: 10.1111/bph.15840] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 02/14/2022] [Accepted: 02/28/2022] [Indexed: 12/14/2022] Open
Abstract
Functional advances have guided our knowledge of physiological and fatal pathological mechanisms of the hormone angiotensin II (AngII) and its antagonists. Such studies revealed that tissue response to a given dose of the hormone or its antagonist depends on receptors that engage the ligand. Thus, we need to know much more about the structures of receptor-ligand complexes at high resolution. Recently, X-ray structures of both AngII receptors (AT1 and AT2 receptors) bound to peptide and non-peptide ligands have been elucidated, providing new opportunities to examine the dynamic fluxes in the 3D architecture of the receptors, as the basis of ligand selectivity, efficacy, and regulation of the molecular functions of the receptors. Constituent structural motifs cooperatively transform ligand selectivity into specific functions, thus conceptualizing the primacy of the 3D structure over individual motifs of receptors. This review covers the new data elucidating the structural dynamics of AngII receptors and how structural knowledge can be transformative in understanding the mechanisms underlying the physiology of AngII.
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Affiliation(s)
- Khuraijam Dhanachandra Singh
- Department of Cardiovascular and Metabolic Sciences, Cleveland Clinic Lerner College of Medicine at Case Western Reserve University, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA
| | - Sadashiva S. Karnik
- Department of Cardiovascular and Metabolic Sciences, Cleveland Clinic Lerner College of Medicine at Case Western Reserve University, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA
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Dale NC, Johnstone EKM, Pfleger KDG. GPCR heteromers: An overview of their classification, function and physiological relevance. Front Endocrinol (Lausanne) 2022; 13:931573. [PMID: 36111299 PMCID: PMC9468249 DOI: 10.3389/fendo.2022.931573] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 08/08/2022] [Indexed: 11/25/2022] Open
Abstract
G protein-coupled receptors (GPCRs) are capable of interacting to form higher order structures such as homomers and heteromers. Heteromerisation in particular has implications for receptor function, with research showing receptors can attain unique expression, ligand binding, signalling and intracellular trafficking upon heteromerisation. As such, GPCR heteromers represent novel drug targets with extensive therapeutic potential. Changes to ligand affinity, efficacy and G protein coupling have all been described, with alterations to these pharmacological aspects now well accepted as common traits for heteromeric complexes. Changes in internalisation and trafficking kinetics, as well as β-arrestin interactions are also becoming more apparent, however, few studies to date have explicitly looked at the implications these factors have upon the signalling profile of a heteromer. Development of ligands to target GPCR heteromers both experimentally and therapeutically has been mostly concentrated on bivalent ligands due to difficulties in identifying and developing heteromer-specific ligands. Improving our understanding of the pharmacology and physiology of GPCR heteromers will enable further development of heteromer-specific ligands with potential to provide therapeutics with increased efficacy and decreased side effects.
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Affiliation(s)
- Natasha C. Dale
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Perth, WA, Australia
| | - Elizabeth K. M. Johnstone
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Perth, WA, Australia
- School of Biomedical Sciences, The University of Western Australia, Nedlands, WA, Australia
- *Correspondence: Kevin D. G. Pfleger, ; Elizabeth K. M. Johnstone,
| | - Kevin D. G. Pfleger
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Perth, WA, Australia
- Dimerix Limited, Nedlands, Australia
- *Correspondence: Kevin D. G. Pfleger, ; Elizabeth K. M. Johnstone,
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7
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Johnstone EKM, Ayoub MA, Hertzman RJ, See HB, Abhayawardana RS, Seeber RM, Pfleger KDG. Novel Pharmacology Following Heteromerization of the Angiotensin II Type 2 Receptor and the Bradykinin Type 2 Receptor. Front Endocrinol (Lausanne) 2022; 13:848816. [PMID: 35721749 PMCID: PMC9204302 DOI: 10.3389/fendo.2022.848816] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 03/21/2022] [Indexed: 01/18/2023] Open
Abstract
The angiotensin type 2 (AT2) receptor and the bradykinin type 2 (B2) receptor are G protein-coupled receptors (GPCRs) that have major roles in the cardiovascular system. The two receptors are known to functionally interact at various levels, and there is some evidence that the observed crosstalk may occur as a result of heteromerization. We investigated evidence for heteromerization of the AT2 receptor and the B2 receptor in HEK293FT cells using various bioluminescence resonance energy transfer (BRET)-proximity based assays, including the Receptor Heteromer Investigation Technology (Receptor-HIT) and the NanoBRET ligand-binding assay. The Receptor-HIT assay showed that Gαq, GRK2 and β-arrestin2 recruitment proximal to AT2 receptors only occurred upon B2 receptor coexpression and activation, all of which is indicative of AT2-B2 receptor heteromerization. Additionally, we also observed specific coupling of the B2 receptor with the Gαz protein, and this was found only in cells coexpressing both receptors and stimulated with bradykinin. The recruitment of Gαz, Gαq, GRK2 and β-arrestin2 was inhibited by B2 receptor but not AT2 receptor antagonism, indicating the importance of B2 receptor activation within AT2-B2 heteromers. The close proximity between the AT2 receptor and B2 receptor at the cell surface was also demonstrated with the NanoBRET ligand-binding assay. Together, our data demonstrate functional interaction between the AT2 receptor and B2 receptor in HEK293FT cells, resulting in novel pharmacology for both receptors with regard to Gαq/GRK2/β-arrestin2 recruitment (AT2 receptor) and Gαz protein coupling (B2 receptor). Our study has revealed a new mechanism for the enigmatic and poorly characterized AT2 receptor to be functionally active within cells, further illustrating the role of heteromerization in the diversity of GPCR pharmacology and signaling.
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Affiliation(s)
- Elizabeth K. M. Johnstone
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Perth, WA, Australia
- School of Biomedical Sciences, The University of Western Australia, Nedlands, WA, Australia
- *Correspondence: Elizabeth K. M. Johnstone, ; Kevin D. G. Pfleger,
| | - Mohammed Akli Ayoub
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Department of Biology, College of Science, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Rebecca J. Hertzman
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- School of Biomedical Sciences, The University of Western Australia, Nedlands, WA, Australia
| | - Heng B. See
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Perth, WA, Australia
| | - Rekhati S. Abhayawardana
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Perth, WA, Australia
| | - Ruth M. Seeber
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Perth, WA, Australia
| | - Kevin D. G. Pfleger
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Perth, WA, Australia
- Dimerix Limited, Nedlands, WA, Australia
- *Correspondence: Elizabeth K. M. Johnstone, ; Kevin D. G. Pfleger,
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8
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Cooper SL, Boyle E, Jefferson SR, Heslop CRA, Mohan P, Mohanraj GGJ, Sidow HA, Tan RCP, Hill SJ, Woolard J. Role of the Renin-Angiotensin-Aldosterone and Kinin-Kallikrein Systems in the Cardiovascular Complications of COVID-19 and Long COVID. Int J Mol Sci 2021; 22:8255. [PMID: 34361021 PMCID: PMC8347967 DOI: 10.3390/ijms22158255] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 07/29/2021] [Accepted: 07/29/2021] [Indexed: 01/08/2023] Open
Abstract
Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is the virus responsible for the COVID-19 pandemic. Patients may present as asymptomatic or demonstrate mild to severe and life-threatening symptoms. Although COVID-19 has a respiratory focus, there are major cardiovascular complications (CVCs) associated with infection. The reported CVCs include myocarditis, heart failure, arrhythmias, thromboembolism and blood pressure abnormalities. These occur, in part, because of dysregulation of the Renin-Angiotensin-Aldosterone System (RAAS) and Kinin-Kallikrein System (KKS). A major route by which SARS-CoV-2 gains cellular entry is via the docking of the viral spike (S) protein to the membrane-bound angiotensin converting enzyme 2 (ACE2). The roles of ACE2 within the cardiovascular and immune systems are vital to ensure homeostasis. The key routes for the development of CVCs and the recently described long COVID have been hypothesised as the direct consequences of the viral S protein/ACE2 axis, downregulation of ACE2 and the resulting damage inflicted by the immune response. Here, we review the impact of COVID-19 on the cardiovascular system, the mechanisms by which dysregulation of the RAAS and KKS can occur following virus infection and the future implications for pharmacological therapies.
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Affiliation(s)
- Samantha L. Cooper
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK;
- Centre of Membrane Proteins and Receptors (COMPARE), School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK
| | - Eleanor Boyle
- School of Medicine, Queen’s Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK; (E.B.); (S.R.J.); (C.R.A.H.); (P.M.); (G.G.J.M.); (H.A.S.); (R.C.P.T.)
| | - Sophie R. Jefferson
- School of Medicine, Queen’s Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK; (E.B.); (S.R.J.); (C.R.A.H.); (P.M.); (G.G.J.M.); (H.A.S.); (R.C.P.T.)
| | - Calum R. A. Heslop
- School of Medicine, Queen’s Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK; (E.B.); (S.R.J.); (C.R.A.H.); (P.M.); (G.G.J.M.); (H.A.S.); (R.C.P.T.)
| | - Pirathini Mohan
- School of Medicine, Queen’s Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK; (E.B.); (S.R.J.); (C.R.A.H.); (P.M.); (G.G.J.M.); (H.A.S.); (R.C.P.T.)
| | - Gearry G. J. Mohanraj
- School of Medicine, Queen’s Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK; (E.B.); (S.R.J.); (C.R.A.H.); (P.M.); (G.G.J.M.); (H.A.S.); (R.C.P.T.)
| | - Hamza A. Sidow
- School of Medicine, Queen’s Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK; (E.B.); (S.R.J.); (C.R.A.H.); (P.M.); (G.G.J.M.); (H.A.S.); (R.C.P.T.)
| | - Rory C. P. Tan
- School of Medicine, Queen’s Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK; (E.B.); (S.R.J.); (C.R.A.H.); (P.M.); (G.G.J.M.); (H.A.S.); (R.C.P.T.)
| | - Stephen J. Hill
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK;
- Centre of Membrane Proteins and Receptors (COMPARE), School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK
| | - Jeanette Woolard
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK;
- Centre of Membrane Proteins and Receptors (COMPARE), School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK
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9
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Delaitre C, Boisbrun M, Lecat S, Dupuis F. Targeting the Angiotensin II Type 1 Receptor in Cerebrovascular Diseases: Biased Signaling Raises New Hopes. Int J Mol Sci 2021; 22:ijms22136738. [PMID: 34201646 PMCID: PMC8269339 DOI: 10.3390/ijms22136738] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Revised: 06/17/2021] [Accepted: 06/20/2021] [Indexed: 12/20/2022] Open
Abstract
The physiological and pathophysiological relevance of the angiotensin II type 1 (AT1) G protein-coupled receptor no longer needs to be proven in the cardiovascular system. The renin–angiotensin system and the AT1 receptor are the targets of several classes of therapeutics (such as angiotensin converting enzyme inhibitors or angiotensin receptor blockers, ARBs) used as first-line treatments in cardiovascular diseases. The importance of AT1 in the regulation of the cerebrovascular system is also acknowledged. However, despite numerous beneficial effects in preclinical experiments, ARBs do not induce satisfactory curative results in clinical stroke studies. A better understanding of AT1 signaling and the development of biased AT1 agonists, able to selectively activate the β-arrestin transduction pathway rather than the Gq pathway, have led to new therapeutic strategies to target detrimental effects of AT1 activation. In this paper, we review the involvement of AT1 in cerebrovascular diseases as well as recent advances in the understanding of its molecular dynamics and biased or non-biased signaling. We also describe why these alternative signaling pathways induced by β-arrestin biased AT1 agonists could be considered as new therapeutic avenues for cerebrovascular diseases.
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Affiliation(s)
- Céline Delaitre
- CITHEFOR, Université de Lorraine, F-54000 Nancy, France;
- Biotechnologie et Signalisation Cellulaire, UMR7242 CNRS/Université de Strasbourg, 300 Boulevard Sébastien Brant, CS 10413, CEDEX, 67412 Illkirch-Graffenstaden, France;
| | | | - Sandra Lecat
- Biotechnologie et Signalisation Cellulaire, UMR7242 CNRS/Université de Strasbourg, 300 Boulevard Sébastien Brant, CS 10413, CEDEX, 67412 Illkirch-Graffenstaden, France;
| | - François Dupuis
- CITHEFOR, Université de Lorraine, F-54000 Nancy, France;
- Correspondence: ; Tel.: +33-372747272
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10
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Fatima N, Patel SN, Hussain T. Angiotensin II Type 2 Receptor: A Target for Protection Against Hypertension, Metabolic Dysfunction, and Organ Remodeling. Hypertension 2021; 77:1845-1856. [PMID: 33840201 PMCID: PMC8115429 DOI: 10.1161/hypertensionaha.120.11941] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The renin-angiotensin system is of vital significance not only in the maintenance of blood pressure but also because of its role in the pathophysiology of different organ systems in the body. Of the 2 Ang II (angiotensin II) receptors, the AT1R (Ang II type 1 receptor) has been extensively studied for its role in mediating the classical functions of Ang II, including vasoconstriction, stimulation of renal tubular sodium reabsorption, hormonal secretion, cell proliferation, inflammation, and oxidative stress. The other receptor, AT2R (Ang II type 2 receptor), is abundantly expressed in both immune and nonimmune cells in fetal tissue. However, its expression is increased under pathological conditions in adult tissues. The role of AT2R in counteracting AT1R function has been discussed in the past 2 decades. However, with the discovery of the nonpeptide agonist C21, the significance of AT2R in various pathologies such as obesity, hypertension, and kidney diseases have been examined. This review focuses on the most recent findings on the beneficial effects of AT2R by summarizing both gene knockout studies as well as pharmacological studies, specifically highlighting its importance in blood pressure regulation, obesity/metabolism, organ protection, and relevance in the treatment of coronavirus disease 2019 (COVID-19).
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Affiliation(s)
- Naureen Fatima
- From the Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, TX
| | - Sanket N Patel
- From the Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, TX
| | - Tahir Hussain
- From the Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, TX
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11
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Takahashi T, Huang Y, Yamamoto K, Hamano G, Kakino A, Kang F, Imaizumi Y, Takeshita H, Nozato Y, Nozato S, Yokoyama S, Nagasawa M, Kawai T, Takeda M, Fujimoto T, Hongyo K, Nakagami F, Akasaka H, Takami Y, Takeya Y, Sugimoto K, Gaisano HY, Sawamura T, Rakugi H. The endocytosis of oxidized LDL via the activation of the angiotensin II type 1 receptor. iScience 2021; 24:102076. [PMID: 33659870 PMCID: PMC7890409 DOI: 10.1016/j.isci.2021.102076] [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] [Received: 06/15/2020] [Revised: 12/06/2020] [Accepted: 01/14/2021] [Indexed: 01/14/2023] Open
Abstract
Arrestin-dependent activation of a G-protein-coupled receptor (GPCR) triggers endocytotic internalization of the receptor complex. We analyzed the interaction between the pattern recognition receptor (PRR) lectin-like oxidized low-density lipoprotein (oxLDL) receptor (LOX-1) and the GPCR angiotensin II type 1 receptor (AT1) to report a hitherto unidentified mechanism whereby internalization of the GPCR mediates cellular endocytosis of the PRR ligand. Using genetically modified Chinese hamster ovary cells, we found that oxLDL activates Gαi but not the Gαq pathway of AT1 in the presence of LOX-1. Endocytosis of the oxLDL-LOX-1 complex through the AT1-β-arrestin pathway was demonstrated by real-time imaging of the membrane dynamics of LOX-1 and visualization of endocytosis of oxLDL. Finally, this endocytotic pathway involving GPCR kinases (GRKs), β-arrestin, and clathrin is relevant in accumulating oxLDL in human vascular endothelial cells. Together, our findings indicate that oxLDL activates selective G proteins and β-arrestin-dependent internalization of AT1, whereby the oxLDL-LOX-1 complex undergoes endocytosis. The binding of oxidized LDL (oxLDL) to LOX-1 induces selective activation of AT1 oxLDL and angiotensin II additively or competitively activate AT1 in different cells oxLDL promotes β-arrestin-dependent internalization of oxLDL-LOX-1-AT1 complex
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Affiliation(s)
- Toshimasa Takahashi
- Department of Geriatric and General Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
- Department of Medicine, University of Toronto, Toronto, Ontario M5S1A8, Canada
| | - Yibin Huang
- Department of Geriatric and General Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Koichi Yamamoto
- Department of Geriatric and General Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
- Corresponding author
| | - Go Hamano
- Department of Geriatric and General Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Akemi Kakino
- Department of Molecular Pathophysiology, Shinshu University Graduate School of Medicine, Matsumoto, Nagano 390-8621, Japan
| | - Fei Kang
- Department of Medicine, University of Toronto, Toronto, Ontario M5S1A8, Canada
| | - Yuki Imaizumi
- Department of Geriatric and General Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Hikari Takeshita
- Department of Geriatric and General Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yoichi Nozato
- Department of Geriatric and General Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Satoko Nozato
- Department of Geriatric and General Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Serina Yokoyama
- Department of Geriatric and General Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Motonori Nagasawa
- Department of Geriatric and General Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Tatsuo Kawai
- Department of Geriatric and General Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Masao Takeda
- Department of Geriatric and General Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Taku Fujimoto
- Department of Geriatric and General Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Kazuhiro Hongyo
- Department of Geriatric and General Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Futoshi Nakagami
- Department of Geriatric and General Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Hiroshi Akasaka
- Department of Geriatric and General Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yoichi Takami
- Department of Geriatric and General Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yasushi Takeya
- Department of Geriatric and General Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Ken Sugimoto
- Department of Geriatric and General Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Herbert Y. Gaisano
- Department of Medicine, University of Toronto, Toronto, Ontario M5S1A8, Canada
| | - Tatsuya Sawamura
- Department of Molecular Pathophysiology, Shinshu University Graduate School of Medicine, Matsumoto, Nagano 390-8621, Japan
| | - Hiromi Rakugi
- Department of Geriatric and General Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
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12
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Soda K, Nakada Y, Iwanari H, Hamakubo T. AT2 receptor interacting protein 1 (ATIP1) mediates COX-2 induction by an AT2 receptor agonist in endothelial cells. Biochem Biophys Rep 2020; 24:100850. [PMID: 33381664 PMCID: PMC7767795 DOI: 10.1016/j.bbrep.2020.100850] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 10/12/2020] [Accepted: 10/27/2020] [Indexed: 01/01/2023] Open
Abstract
Angiotensin II (Ang II) type 2 receptor (AT2R) is one of the major components of the renin-angiotensin-aldosterone system. Nevertheless, the physiological role is not well defined compared to the understanding of the Ang II type 1 receptor (AT1R), which is a well characterized G-protein coupled receptor in the cardiovascular system. While the AT2R signaling pathway remains unclear, AT2 receptor interacting protein 1 (ATIP1) has been identified as a candidate molecule for interacting with the C-terminal region of AT2R. In this study, we investigated the ATIP1 dependent AT2R inducible genes in human umbilical vein endothelial cells (HUVECs). CGP42112A, an AT2R specific agonist, resulted in an upregulation of inflammatory genes in HUVECs, which were inhibited by knocking down ATIP1 with siRNA (siATIP1). Among them, we confirmed by quantitative PCR that the induction of COX-2 mRNA expression was significantly downregulated by siATIP1. COX-2 was also upregulated by Ang II stimulation. This upregulation was suppressed by treatment with the AT2R specific antagonist PD123319, which was not replicated by the AT1R antagonist telmisartan. These findings suggest that ATIP1 plays an important role in AT2R dependent inflammatory responses. This may provide a new approach to the development of cardio-protective drugs. Only the AT2 receptor interacting protein 1 (ATIP1) of ATIP isoforms expresses in endothelial cells. A novel anti-ATIP monoclonal antibody detected endogenous ATIP1 and revealed ATIP1 localization in endothelial cells. AT2 receptor (AT2R) agonist stimulation induced inflammatory gene expression via ATIP1 in endothelial cells. An AT2R specific inhibitor blocks the Ang II induction of COX-2 mRNA in endothelial cells. There is the AT2R-ATIP1 related pathway of COX-2 induction in endothelial cells.
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Affiliation(s)
- Keita Soda
- Department of Quantitative Biology and Medicine, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan.,Department of Protein - Protein Interaction Research, Institute for Advanced Medical Sciences, Nippon Medical School, Tokyo, Japan
| | - Yoshiko Nakada
- Department of Quantitative Biology and Medicine, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
| | - Hiroko Iwanari
- Department of Quantitative Biology and Medicine, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
| | - Takao Hamakubo
- Department of Quantitative Biology and Medicine, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan.,Department of Protein - Protein Interaction Research, Institute for Advanced Medical Sciences, Nippon Medical School, Tokyo, Japan
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13
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Kikuchi K, Fujita Y, Shen X, Liu J, Terakawa T, Nishikata D, Niibori S, Ito T, Ashidate K, Kikuchi T, Kikuchi Y, Maeda T, Zou K, Komano H. Interaction between Angiotensin Receptor and β-Adrenergic Receptor Regulates the Production of Amyloid β-Protein. Biol Pharm Bull 2020; 43:731-735. [PMID: 32238715 DOI: 10.1248/bpb.b20-00007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Alzheimer's disease (AD) is characterized by the formation of extracellular amyloid plaques containing the amyloid β-protein (Aβ) within the parenchyma of the brain. Aβ is considered to be the key pathogenic factor of AD. Recently, we showed that Angiotensin II type 1 receptor (AT1R), which regulates blood pressure, is involved in Aβ production, and that telmisartan (Telm), which is an angiotensin II receptor blocker (ARB), increased Aβ production via AT1R. However, the precise mechanism underlying how AT1R is involved in Aβ production is unknown. Interestingly, AT1R, a G protein-coupled receptor, was strongly suggested to be involved in signal transduction by heterodimerization with β2-adrenergic receptor (β2-AR), which is also shown to be involved in Aβ generation. Therefore, in this study, we aimed to clarify whether the interaction between AT1R and β2-AR is involved in the regulation of Aβ production. To address this, we analyzed whether the increase in Aβ production by Telm treatment is affected by β-AR antagonist using fibroblasts overexpressing amyloid precursor protein (APP). We found that the increase in Aβ production by Telm treatment was decreased by the treatment of β2-AR selective antagonist ICI-118551 more strongly than the treatment of β1-AR selective antagonists. Furthermore, deficiency of AT1R abolished the effect of β2-AR antagonist on the stimulation of Aβ production caused by Telm. Taken together, the interaction between AT1R and β2-AR is likely to be involved in Aβ production.
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Affiliation(s)
- Kota Kikuchi
- Division of Neuroscience, Department of Biological Pharmacy, School of Pharmacy, Iwate Medical University.,Department of Pharmacy, Japanese Red Cross Morioka Hospital
| | - Yu Fujita
- Division of Neuroscience, Department of Biological Pharmacy, School of Pharmacy, Iwate Medical University
| | - Xuefeng Shen
- Division of Neuroscience, Department of Biological Pharmacy, School of Pharmacy, Iwate Medical University
| | - Junjun Liu
- Division of Neuroscience, Department of Biological Pharmacy, School of Pharmacy, Iwate Medical University
| | - Tomoki Terakawa
- Division of Neuroscience, Department of Biological Pharmacy, School of Pharmacy, Iwate Medical University
| | - Daiki Nishikata
- Division of Neuroscience, Department of Biological Pharmacy, School of Pharmacy, Iwate Medical University
| | - Sho Niibori
- Division of Neuroscience, Department of Biological Pharmacy, School of Pharmacy, Iwate Medical University
| | - Takayuki Ito
- Division of Neuroscience, Department of Biological Pharmacy, School of Pharmacy, Iwate Medical University
| | - Kazuyuki Ashidate
- Division of Neuroscience, Department of Biological Pharmacy, School of Pharmacy, Iwate Medical University
| | - Takuya Kikuchi
- Division of Neuroscience, Department of Biological Pharmacy, School of Pharmacy, Iwate Medical University
| | - Yu Kikuchi
- Division of Neuroscience, Department of Biological Pharmacy, School of Pharmacy, Iwate Medical University
| | - Tomoji Maeda
- Department of Pharmacology, Nihon Pharmaceutical University
| | - Kun Zou
- Department of Biochemistry, School of Medicine, Nagoya City University
| | - Hiroto Komano
- Division of Neuroscience, Department of Biological Pharmacy, School of Pharmacy, Iwate Medical University
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14
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Connolly A, Holleran BJ, Simard É, Baillargeon JP, Lavigne P, Leduc R. Interplay between intracellular loop 1 and helix VIII of the angiotensin II type 2 receptor controls its activation. Biochem Pharmacol 2019; 168:330-338. [PMID: 31348898 DOI: 10.1016/j.bcp.2019.07.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 07/19/2019] [Indexed: 01/09/2023]
Abstract
The signaling mechanisms of the angiotensin II type 2 receptor (AT2R), a heptahelical receptor, have not yet been clearly and completely defined. In the present contribution, we set out to identify the molecular determinants involved in AT2R activation. Although AT2R has not been shown to engage Gq/11, G12, Gi2, and β-arrestin (βarr) pathways as does the AT1R upon angiotensin II (AngII) stimulation, the atypical positioning of helix VIII in the recently published AT2R structure may play a role in the receptor's capacity to couple to downstream effectors. In the AT2R structure, helix VIII points inwards and towards intracellular loop 3 (ICL3) to form tertiary interactions with transmembrane domain 6 (TM6), possibly impeding access to signaling effectors. On the other hand, in most class A GPCRs, helix VIII is found to be engaged in tertiary interactions with ICL1 and away from the effector binding site. Upon closer examination of the AT2R structure, we found that the residues contained within intracellular loop 1 (ICL1) may be involved in driving this unusual conformation of helix VIII. To explore this hypothesis, we designed a series of AT1R/AT2R receptor chimeras to validate the roles of ICL1 and helix VIII in AT2R signaling. Substituting the AT1R ICL1 into AT2R led to a mutant receptor that coupled to Gi2. The substitution of the helix VIII and C-terminal domains of AT2R into the AT1R backbone led to a mutant receptor that retained AT1R-like signaling properties. These results suggest that the C-terminal portion of AT2R is compatible with canonical GPCR signaling and that ICL1 of AT2R is involved in repositioning helix VIII, which impedes engagement of classical GPCR effectors such as G proteins or βarrs.
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Affiliation(s)
- Alexandre Connolly
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada; Institut de Pharmacologie de Sherbrooke, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Brian J Holleran
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada; Institut de Pharmacologie de Sherbrooke, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Élie Simard
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada; Institut de Pharmacologie de Sherbrooke, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Jean-Patrice Baillargeon
- Division of Endocrinology, Department of Medicine, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke J1H 5N4, Québec, Canada
| | - Pierre Lavigne
- Institut de Pharmacologie de Sherbrooke, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada; Department of Biochemistry, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Richard Leduc
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada; Institut de Pharmacologie de Sherbrooke, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada.
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15
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Takenaka T, Inoue T, Miyazaki T, Kobori H, Nishiyama A, Ishii N, Hayashi M, Suzuki H. Klotho Ameliorates Medullary Fibrosis and Pressure Natriuresis in Hypertensive Rat Kidneys. Hypertension 2019; 72:1151-1159. [PMID: 30354813 DOI: 10.1161/hypertensionaha.118.11176] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Renal expression of klotho is reduced in hypertension. Experiments were performed to examine whether exogenous klotho protein supplementation ameliorates pressure natriuresis in early phase of hypertension, using stroke-prone spontaneously hypertensive rats (sp-SHR). The interactions between klotho protein and renal renin-Ang (angiotensin) system were examined with immunoprecipitation and cell culture methods. Uninephrectomy was performed in sp-SHRs to induce nephrosclerosis, and they were treated with exogenous klotho protein or vehicle. Exogenous klotho protein supplementation to sp-SHR decreased blood pressure, renal Ang II levels, AGT (angiotensinogen) expression, HIF (hypoxia-inducible factor)-1α abundance, and medullary fibronectin levels, with increased renal klotho expression and serum and urine klotho levels. Klotho supplementation also reduced kidney weight, renal phosphorylated Akt, and mTOR (mammalian target of rapamycin) abundance. Furthermore, klotho supplementation restored renal autoregulation of glomerular filtration rate and enhanced pressure-induced natriuresis in sp-SHR. Klotho protein bound to AT1R (Ang II type-1 receptor) and decreased the presence of AT1R on HK-2 (human proximal tubular) cells, attenuating inositol triphosphate generation. Klotho protein suppressed Ang II-induced increments of AGT expression in HK-2 cells. Collectively, the present data demonstrate that klotho binds with the AT1R to suppress Ang signal transduction, participating in inactivating renal renin-Ang system. Our results also suggest that exogenous klotho supplementation represses Akt-mTOR signaling to reduce renal hypertrophy and restore the autoregulatory ability of glomerular filtration rate in uninephrectomized sp-SHRs. Finally, the present findings implicate that klotho supplementation inhibits HIF-1α pathway and medullary fibrosis, contributing to enhancements of pressure natriuresis and reduction in blood pressure.
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Affiliation(s)
- Tsuneo Takenaka
- From the Department of Medicine, International University of Health and Welfare, Minato, Tokyo, Japan (T.T., H.K.)
| | - Tsutomu Inoue
- Department of Nephrology, Saitama Medical University, Iruma, Japan (T.I., T.M., H.S.)
| | - Takashi Miyazaki
- Department of Nephrology, Saitama Medical University, Iruma, Japan (T.I., T.M., H.S.)
| | - Hiroyuki Kobori
- From the Department of Medicine, International University of Health and Welfare, Minato, Tokyo, Japan (T.T., H.K.)
| | - Akira Nishiyama
- Department of Pharmacology, Kagawa University, Kita, Japan (A.N.)
| | - Naohito Ishii
- Department of Clinical Chemistry, Kitasato University, Sagamihara, Kanagawa, Japan (N.I.)
| | - Matsuhiko Hayashi
- Blood Purification Center, Keio University, Shinjuku, Tokyo, Japan (M.H.)
| | - Hiromichi Suzuki
- Department of Nephrology, Saitama Medical University, Iruma, Japan (T.I., T.M., H.S.)
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16
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Turu G, Balla A, Hunyady L. The Role of β-Arrestin Proteins in Organization of Signaling and Regulation of the AT1 Angiotensin Receptor. Front Endocrinol (Lausanne) 2019; 10:519. [PMID: 31447777 PMCID: PMC6691095 DOI: 10.3389/fendo.2019.00519] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 07/15/2019] [Indexed: 12/30/2022] Open
Abstract
AT1 angiotensin receptor plays important physiological and pathophysiological roles in the cardiovascular system. Renin-angiotensin system represents a target system for drugs acting at different levels. The main effects of ATR1 stimulation involve activation of Gq proteins and subsequent IP3, DAG, and calcium signaling. It has become evident in recent years that besides the well-known G protein pathways, AT1R also activates a parallel signaling pathway through β-arrestins. β-arrestins were originally described as proteins that desensitize G protein-coupled receptors, but they can also mediate receptor internalization and G protein-independent signaling. AT1R is one of the most studied receptors, which was used to unravel the newly recognized β-arrestin-mediated pathways. β-arrestin-mediated signaling has become one of the most studied topics in recent years in molecular pharmacology and the modulation of these pathways of the AT1R might offer new therapeutic opportunities in the near future. In this paper, we review the recent advances in the field of β-arrestin signaling of the AT1R, emphasizing its role in cardiovascular regulation and heart failure.
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Affiliation(s)
- Gábor Turu
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
- MTA-SE Laboratory of Molecular Physiology, Semmelweis University, Hungarian Academy of Sciences, Budapest, Hungary
| | - András Balla
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
- MTA-SE Laboratory of Molecular Physiology, Semmelweis University, Hungarian Academy of Sciences, Budapest, Hungary
| | - László Hunyady
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
- MTA-SE Laboratory of Molecular Physiology, Semmelweis University, Hungarian Academy of Sciences, Budapest, Hungary
- *Correspondence: László Hunyady
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17
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O'Brien SL, Johnstone EKM, Devost D, Conroy J, Reichelt ME, Purdue BW, Ayoub MA, Kawai T, Inoue A, Eguchi S, Hébert TE, Pfleger KDG, Thomas WG. BRET-based assay to monitor EGFR transactivation by the AT 1R reveals G q/11 protein-independent activation and AT 1R-EGFR complexes. Biochem Pharmacol 2018; 158:232-242. [PMID: 30347205 DOI: 10.1016/j.bcp.2018.10.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 10/17/2018] [Indexed: 01/09/2023]
Abstract
The type 1 angiotensin II (AngII) receptor (AT1R) transactivates the epidermal growth factor receptor (EGFR), which leads to pathological remodeling of heart, blood vessels and kidney. End-point assays are used as surrogates of EGFR activation, however these downstream readouts are not applicable to live cells, in real-time. Herein, we report the use of a bioluminescence resonance energy transfer (BRET)-based assay to assess recruitment of the EGFR adaptor protein, growth factor receptor-bound protein 2 (Grb2), to the EGFR. In a variety of cell lines, both epidermal growth factor (EGF) and AngII stimulated Grb2 recruitment to EGFR. The BRET assay was used to screen a panel of 9 G protein-coupled receptors (GPCRs) and further developed for other EGFR family members (HER2 and HER3); the AT1R was able to transactivate HER2, but not HER3. Mechanistically, AT1R-mediated ERK1/2 activation was dependent on Gq/11 and EGFR tyrosine kinase activity, whereas the recruitment of Grb2 to the EGFR was independent of Gq/11 and only partially dependent on EGFR tyrosine kinase activity. This Gq/11 independence of EGFR transactivation was confirmed using AT1R mutants and in CRISPR cell lines lacking Gq/11. EGFR transactivation was also apparently independent of β-arrestins. Finally, we used additional BRET-based assays and confocal microscopy to provide evidence that both AngII- and EGF-stimulation promoted AT1R-EGFR heteromerization. In summary, we report an alternative approach to monitoring AT1R-EGFR transactivation in live cells, which provides a more direct and proximal view of this process, including the potential for complexes between the AT1R and EGFR.
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Affiliation(s)
- Shannon L O'Brien
- Receptor Biology Group, The School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia 4072, Queensland, Australia
| | - Elizabeth K M Johnstone
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and Centre for Medical Research, The University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Dominic Devost
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
| | - Jacinta Conroy
- Receptor Biology Group, The School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia 4072, Queensland, Australia
| | - Melissa E Reichelt
- Receptor Biology Group, The School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia 4072, Queensland, Australia
| | - Brooke W Purdue
- Receptor Biology Group, The School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia 4072, Queensland, Australia
| | - Mohammed A Ayoub
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and Centre for Medical Research, The University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Tatsuo Kawai
- Cardiovascular Research Centre, Department of Physiology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States
| | - Asuka Inoue
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Satoru Eguchi
- Cardiovascular Research Centre, Department of Physiology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States
| | - Terence E Hébert
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
| | - Kevin D G Pfleger
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and Centre for Medical Research, The University of Western Australia, Crawley, Western Australia 6009, Australia; Dimerix Limited, Nedlands, Western Australia 6009, Australia
| | - Walter G Thomas
- Receptor Biology Group, The School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia 4072, Queensland, Australia; Centre for Cardiac and Vasculature Biology, The University of Queensland, St Lucia 4072, Queensland, Australia.
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18
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Angiotensin II cyclic analogs as tools to investigate AT 1R biased signaling mechanisms. Biochem Pharmacol 2018; 154:104-117. [PMID: 29684376 DOI: 10.1016/j.bcp.2018.04.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 04/18/2018] [Indexed: 01/14/2023]
Abstract
G protein coupled receptors (GPCRs) produce pleiotropic effects by their capacity to engage numerous signaling pathways once activated. Functional selectivity (also called biased signaling), where specific compounds can bring GPCRs to adopt conformations that enable selective receptor coupling to distinct signaling pathways, continues to be significantly investigated. However, an important but often overlooked aspect of functional selectivity is the capability of ligands such as angiotensin II (AngII) to adopt specific conformations that may preferentially bind to selective GPCRs structures. Understanding both receptor and ligand conformation is of the utmost importance for the design of new drugs targeting GPCRs. In this study, we examined the properties of AngII cyclic analogs to impart biased agonism on the angiotensin type 1 receptor (AT1R). Positions 3 and 5 of AngII were substituted for cysteine and homocysteine residues ([Sar1Hcy3,5]AngII, [Sar1Cys3Hcy5]AngII and [Sar1Cys3,5]AngII) and the resulting analogs were evaluated for their capacity to activate the Gq/11, G12, Gi2, Gi3, Gz, ERK and β-arrestin (βarr) signaling pathways via AT1R. Interestingly, [Sar1Hcy3,5]AngII exhibited potency and full efficacy on all pathways tested with the exception of the Gq pathway. Molecular dynamic simulations showed that the energy barrier associated with the insertion of residue Phe8 of AngII within the hydrophobic core of AT1R, associated with Gq/11 activation, is increased with [Sar1Hcy3,5]AngII. These results suggest that constraining the movements of molecular determinants within a given ligand by introducing cyclic structures may lead to the generation of novel ligands providing more efficient biased agonism.
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19
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Angiotensin II type 2 receptor (AT2R) in renal and cardiovascular disease. Clin Sci (Lond) 2017; 130:1307-26. [PMID: 27358027 DOI: 10.1042/cs20160243] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 05/06/2016] [Indexed: 12/14/2022]
Abstract
Angiotensin II (Ang II) is well-considered to be the principal effector of the renin-angiotensin system (RAS), which binds with strong affinity to the angiotensin II type 1 (AT1R) and type 2 (AT2R) receptor subtype. However, activation of both receptors is likely to stimulate different signalling mechanisms/pathways and produce distinct biological responses. The haemodynamic and non-haemodynamic effects of Ang II, including its ability to regulate blood pressure, maintain water-electrolyte balance and promote vasoconstriction and cellular growth are well-documented to be mediated primarily by the AT1R. However, its biological and functional effects mediated through the AT2R subtype are still poorly understood. Recent studies have emphasized that activation of the AT2R regulates tissue and organ development and provides in certain context a potential counter-regulatory mechanism against AT1R-mediated actions. Thus, this review will focus on providing insights into the biological role of the AT2R, in particular its actions within the renal and cardiovascular system.
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20
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Carey RM. AT2 Receptors: Potential Therapeutic Targets for Hypertension. Am J Hypertens 2017; 30:339-347. [PMID: 27664954 DOI: 10.1093/ajh/hpw121] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 09/07/2016] [Indexed: 12/15/2022] Open
Abstract
The renin-angiotensin system (RAS) is arguably the most important and best studied hormonal system in the control of blood pressure (BP) and the pathogenesis of hypertension. The RAS features its main effector angiotensin II (Ang II) acting via its 2 major receptors, angiotensin type-1(AT1R) and type-2 (AT2R). In general, AT2Rs oppose the detrimental actions of Ang II via AT1Rs. AT2R activation induces vasodilation and natriuresis, but its effects to lower BP in hypertension have not been as clear as anticipated. Recent studies, however, have demonstrated that acute and chronic AT2R stimulation can induce natriuresis and lower BP in the Ang II infusion model of experimental hypertension. AT2R activation induces receptor recruitment from intracellular sites to the apical plasma membranes of renal proximal tubule cells via a bradykinin, nitric oxide, and cyclic guanosine 3',5' monophosphate signaling pathway that results in internalization and inactivation of sodium (Na+) transporters Na+-H+ exchanger-3 and Na+/K+ATPase. These responses do not require the presence of concurrent AT1R blockade and are effective both in the prevention and reversal of hypertension. This review will address the role of AT2Rs in the control of BP and Na+ excretion and the case for these receptors as potential therapeutic targets for hypertension in humans.
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Affiliation(s)
- Robert M Carey
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia Health System, Charlottesville, Virginia, USA
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21
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Microvascular vasodilator properties of the angiotensin II type 2 receptor in a mouse model of type 1 diabetes. Sci Rep 2017; 7:45625. [PMID: 28361992 PMCID: PMC5374544 DOI: 10.1038/srep45625] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 03/01/2017] [Indexed: 12/02/2022] Open
Abstract
Diabetes Mellitus is associated with severe cardiovascular disorders involving the renin-angiotensin system, mainly through activation of the angiotensin II type 1 receptor (AT1R). Although the type 2 receptor (AT2R) opposes the effects of AT1R, with vasodilator and anti-trophic properties, its role in diabetes is debatable. Thus we investigated AT2R-mediated dilatation in a model of type 1 diabetes induced by streptozotocin in 5-month-old male mice lacking AT2R (AT2R−/y). Glucose tolerance was reduced and markers of inflammation and oxidative stress (cyclooxygenase-2, gp91phox p22phox and p67phox) were increased in AT2R−/y mice compared to wild-type (WT) animals. Streptozotocin-induced hyperglycaemia was higher in AT2R−/y than in WT mice. Arterial gp91phox and MnSOD expression levels in addition to blood 8-isoprostane and creatinine were further increased in diabetic AT2R−/y mice compared to diabetic WT mice. AT2R-dependent dilatation in both isolated mesenteric resistance arteries and perfused kidneys was greater in diabetic mice than in non-diabetic animals. Thus, in type 1 diabetes, AT2R may reduce glycaemia and display anti-oxidant and/or anti-inflammatory properties in association with greater vasodilatation in mesenteric arteries and in the renal vasculature, a major target of diabetes. Therefore AT2R might represent a new therapeutic target in diabetes.
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22
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Tóth AD, Gyombolai P, Szalai B, Várnai P, Turu G, Hunyady L. Angiotensin type 1A receptor regulates β-arrestin binding of the β 2-adrenergic receptor via heterodimerization. Mol Cell Endocrinol 2017; 442:113-124. [PMID: 27908837 DOI: 10.1016/j.mce.2016.11.027] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 10/26/2016] [Accepted: 11/26/2016] [Indexed: 02/06/2023]
Abstract
Heterodimerization between angiotensin type 1A receptor (AT1R) and β2-adrenergic receptor (β2AR) has been shown to modulate G protein-mediated effects of these receptors. Activation of G protein-coupled receptors (GPCRs) leads to β-arrestin binding, desensitization, internalization and G protein-independent signaling of GPCRs. Our aim was to study the effect of heterodimerization on β-arrestin coupling. We found that β-arrestin binding of β2AR is affected by activation of AT1Rs. Costimulation with angiotensin II and isoproterenol markedly enhanced the interaction between β2AR and β-arrestins, by prolonging the lifespan of β2AR-induced β-arrestin2 clusters at the plasma membrane. While candesartan, a conventional AT1R antagonist, had no effect on the β-arrestin2 binding to β2AR, TRV120023, a β-arrestin biased agonist, enhanced the interaction. These findings reveal a new crosstalk mechanism between AT1R and β2AR, and suggest that enhanced β-arrestin2 binding to β2AR can contribute to the pharmacological effects of biased AT1R agonists.
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Affiliation(s)
- András D Tóth
- Department of Physiology, Faculty of Medicine, Semmelweis University, P. O. Box 2, H-1428 Budapest, Hungary
| | - Pál Gyombolai
- Department of Physiology, Faculty of Medicine, Semmelweis University, P. O. Box 2, H-1428 Budapest, Hungary; MTA-SE Laboratory of Molecular Physiology, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary
| | - Bence Szalai
- Department of Physiology, Faculty of Medicine, Semmelweis University, P. O. Box 2, H-1428 Budapest, Hungary; MTA-SE Laboratory of Molecular Physiology, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary
| | - Péter Várnai
- Department of Physiology, Faculty of Medicine, Semmelweis University, P. O. Box 2, H-1428 Budapest, Hungary
| | - Gábor Turu
- Department of Physiology, Faculty of Medicine, Semmelweis University, P. O. Box 2, H-1428 Budapest, Hungary; MTA-SE Laboratory of Molecular Physiology, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary
| | - László Hunyady
- Department of Physiology, Faculty of Medicine, Semmelweis University, P. O. Box 2, H-1428 Budapest, Hungary; MTA-SE Laboratory of Molecular Physiology, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary.
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23
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Inuzuka T, Fujioka Y, Tsuda M, Fujioka M, Satoh AO, Horiuchi K, Nishide S, Nanbo A, Tanaka S, Ohba Y. Attenuation of ligand-induced activation of angiotensin II type 1 receptor signaling by the type 2 receptor via protein kinase C. Sci Rep 2016; 6:21613. [PMID: 26857745 PMCID: PMC4746669 DOI: 10.1038/srep21613] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 01/27/2016] [Indexed: 11/23/2022] Open
Abstract
Angiotensin II (AII) type 2 receptor (AT2R) negatively regulates type 1 receptor (AT1R) signaling. However, the precise molecular mechanism of AT2R-mediated AT1R inhibition remains poorly understood. Here, we characterized the local and functional interaction of AT2R with AT1R. AT2R colocalized and formed a complex with AT1R at the plasma membrane, even in the absence of AII. Upon AII stimulation, the spatial arrangement of the complex was modulated, as confirmed by Förster resonance energy transfer (FRET) analysis, followed by AT2R internalization along with AT1R. AT2R internalization was specifically observed only in the presence of AT1R; AT2R alone could not be internalized. The AT1R-specific inhibitor losartan completely inhibited both the conformational change and the internalization of AT2R with AT1R, whereas the AT2R-specific inhibitor PD123319 partially hindered these phenomena, demonstrating that the activation of both receptors was indispensable for these effects. In addition, treatment with the protein kinase C (PKC) inhibitors inhibited the ligand-dependent accumulation of AT2R but not that of AT1R in the endosomes. A mutation in the putative phosphorylation sites of AT2R also abrogated the co-internalization of ATR2 with AT1R and the inhibitory effect of ATR2 on AT1R. These data suggest that AT2R inhibits ligand-induced AT1R signaling through the PKC-dependent pathway.
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Affiliation(s)
- Takayuki Inuzuka
- Department of Cell Physiology, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan
| | - Yoichiro Fujioka
- Department of Cell Physiology, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan
| | - Masumi Tsuda
- Department of Cancer Pathology, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan
| | - Mari Fujioka
- Department of Cell Physiology, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan
| | - Aya O Satoh
- Department of Cell Physiology, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan
| | - Kosui Horiuchi
- Department of Cell Physiology, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan
| | - Shinya Nishide
- Department of Cell Physiology, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan
| | - Asuka Nanbo
- Department of Cell Physiology, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan
| | - Shinya Tanaka
- Department of Cancer Pathology, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan
| | - Yusuke Ohba
- Department of Cell Physiology, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan
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24
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Karnik SS, Unal H, Kemp JR, Tirupula KC, Eguchi S, Vanderheyden PML, Thomas WG. International Union of Basic and Clinical Pharmacology. XCIX. Angiotensin Receptors: Interpreters of Pathophysiological Angiotensinergic Stimuli [corrected]. Pharmacol Rev 2015; 67:754-819. [PMID: 26315714 PMCID: PMC4630565 DOI: 10.1124/pr.114.010454] [Citation(s) in RCA: 207] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The renin angiotensin system (RAS) produced hormone peptides regulate many vital body functions. Dysfunctional signaling by receptors for RAS peptides leads to pathologic states. Nearly half of humanity today would likely benefit from modern drugs targeting these receptors. The receptors for RAS peptides consist of three G-protein-coupled receptors—the angiotensin II type 1 receptor (AT1 receptor), the angiotensin II type 2 receptor (AT2 receptor), the MAS receptor—and a type II trans-membrane zinc protein—the candidate angiotensin IV receptor (AngIV binding site). The prorenin receptor is a relatively new contender for consideration, but is not included here because the role of prorenin receptor as an independent endocrine mediator is presently unclear. The full spectrum of biologic characteristics of these receptors is still evolving, but there is evidence establishing unique roles of each receptor in cardiovascular, hemodynamic, neurologic, renal, and endothelial functions, as well as in cell proliferation, survival, matrix-cell interaction, and inflammation. Therapeutic agents targeted to these receptors are either in active use in clinical intervention of major common diseases or under evaluation for repurposing in many other disorders. Broad-spectrum influence these receptors produce in complex pathophysiological context in our body highlights their role as precise interpreters of distinctive angiotensinergic peptide cues. This review article summarizes findings published in the last 15 years on the structure, pharmacology, signaling, physiology, and disease states related to angiotensin receptors. We also discuss the challenges the pharmacologist presently faces in formally accepting newer members as established angiotensin receptors and emphasize necessary future developments.
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Affiliation(s)
- Sadashiva S Karnik
- Department of Molecular Cardiology, Lerner Research Institute of Cleveland Clinic, Cleveland, Ohio (S.S.K., H.U., J.R.K., K.C.T.); Cardiovascular Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania (S.E.); Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium (P.M.L.V.); and Department of General Physiology, School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia (W.G.T.)
| | - Hamiyet Unal
- Department of Molecular Cardiology, Lerner Research Institute of Cleveland Clinic, Cleveland, Ohio (S.S.K., H.U., J.R.K., K.C.T.); Cardiovascular Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania (S.E.); Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium (P.M.L.V.); and Department of General Physiology, School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia (W.G.T.)
| | - Jacqueline R Kemp
- Department of Molecular Cardiology, Lerner Research Institute of Cleveland Clinic, Cleveland, Ohio (S.S.K., H.U., J.R.K., K.C.T.); Cardiovascular Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania (S.E.); Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium (P.M.L.V.); and Department of General Physiology, School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia (W.G.T.)
| | - Kalyan C Tirupula
- Department of Molecular Cardiology, Lerner Research Institute of Cleveland Clinic, Cleveland, Ohio (S.S.K., H.U., J.R.K., K.C.T.); Cardiovascular Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania (S.E.); Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium (P.M.L.V.); and Department of General Physiology, School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia (W.G.T.)
| | - Satoru Eguchi
- Department of Molecular Cardiology, Lerner Research Institute of Cleveland Clinic, Cleveland, Ohio (S.S.K., H.U., J.R.K., K.C.T.); Cardiovascular Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania (S.E.); Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium (P.M.L.V.); and Department of General Physiology, School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia (W.G.T.)
| | - Patrick M L Vanderheyden
- Department of Molecular Cardiology, Lerner Research Institute of Cleveland Clinic, Cleveland, Ohio (S.S.K., H.U., J.R.K., K.C.T.); Cardiovascular Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania (S.E.); Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium (P.M.L.V.); and Department of General Physiology, School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia (W.G.T.)
| | - Walter G Thomas
- Department of Molecular Cardiology, Lerner Research Institute of Cleveland Clinic, Cleveland, Ohio (S.S.K., H.U., J.R.K., K.C.T.); Cardiovascular Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania (S.E.); Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium (P.M.L.V.); and Department of General Physiology, School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia (W.G.T.)
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25
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Kroeze WK, Sassano MF, Huang XP, Lansu K, McCorvy JD, Giguère PM, Sciaky N, Roth BL. PRESTO-Tango as an open-source resource for interrogation of the druggable human GPCRome. Nat Struct Mol Biol 2015; 22:362-9. [PMID: 25895059 PMCID: PMC4424118 DOI: 10.1038/nsmb.3014] [Citation(s) in RCA: 468] [Impact Index Per Article: 52.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Accepted: 03/25/2015] [Indexed: 01/14/2023]
Abstract
G protein-coupled receptors (GPCRs) are essential mediators of cellular signaling and are important targets of drug action. Of the approximately 350 nonolfactory human GPCRs, more than 100 are still considered to be 'orphans' because their endogenous ligands remain unknown. Here, we describe a unique open-source resource that allows interrogation of the druggable human GPCRome via a G protein-independent β-arrestin-recruitment assay. We validate this unique platform at more than 120 nonorphan human GPCR targets, demonstrate its utility for discovering new ligands for orphan human GPCRs and describe a method (parallel receptorome expression and screening via transcriptional output, with transcriptional activation following arrestin translocation (PRESTO-Tango)) for the simultaneous and parallel interrogation of the entire human nonolfactory GPCRome.
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Affiliation(s)
- Wesley K Kroeze
- 1] Department of Pharmacology, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, USA. [2] National Institute of Mental Health Psychoactive Drug Screening Program, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, USA
| | - Maria F Sassano
- 1] Department of Pharmacology, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, USA. [2] National Institute of Mental Health Psychoactive Drug Screening Program, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, USA
| | - Xi-Ping Huang
- 1] Department of Pharmacology, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, USA. [2] National Institute of Mental Health Psychoactive Drug Screening Program, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, USA
| | - Katherine Lansu
- Department of Pharmacology, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, USA
| | - John D McCorvy
- Department of Pharmacology, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, USA
| | - Patrick M Giguère
- Department of Pharmacology, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, USA
| | - Noah Sciaky
- Department of Pharmacology, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, USA
| | - Bryan L Roth
- 1] Department of Pharmacology, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, USA. [2] National Institute of Mental Health Psychoactive Drug Screening Program, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, USA. [3] Program in Neuroscience, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, USA. [4] Division of Chemical Biology and Medicinal Chemistry, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, USA
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26
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Activation of intracellular angiotensin AT₂ receptors induces rapid cell death in human uterine leiomyosarcoma cells. Clin Sci (Lond) 2015; 128:567-78. [PMID: 25487516 DOI: 10.1042/cs20140627] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The presence of angiotensin type 2 (AT₂) receptors in mitochondria and their role in NO generation and cell aging were recently demonstrated in various human and mouse non-tumour cells. We investigated the intracellular distribution of AT₂ receptors including their presence in mitochondria and their role in the induction of apoptosis and cell death in cultured human uterine leiomyosarcoma (SK-UT-1) cells and control human uterine smooth muscle cells (HutSMC). The intracellular levels of the AT₂ receptor are low in proliferating SK-UT-1 cells but the receptor is substantially up-regulated in quiescent SK-UT-1 cells with high densities in mitochondria. Activation of the cell membrane AT₂ receptors by a concomitant treatment with angiotensin II and the AT₁ receptor antagonist, losartan, induces apoptosis but does not affect the rate of cell death. We demonstrate for the first time that the high-affinity, non-peptide AT₂ receptor agonist, Compound 21 (C21), penetrates the cell membrane of quiescent SK-UT-1 cells, activates intracellular AT₂ receptors and induces rapid cell death; approximately 70% of cells died within 24 h. The cells, which escaped cell death, displayed activation of the mitochondrial apoptotic pathway, i.e. down-regulation of the Bcl-2 protein, induction of the Bax protein and activation of caspase-3. All quiescent SK-UT-1 cells died within 5 days after treatment with a single dose of C21. C21 was devoid of cytotoxic effects in proliferating SK-UT-1 cells and in quiescent HutSMC. Our results point to a new, unique approach enabling the elimination non-cycling uterine leiomyosarcoma cells providing that they over-express the AT₂ receptor.
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Szakadáti G, Tóth AD, Oláh I, Erdélyi LS, Balla T, Várnai P, Hunyady L, Balla A. Investigation of the fate of type I angiotensin receptor after biased activation. Mol Pharmacol 2015; 87:972-81. [PMID: 25804845 DOI: 10.1124/mol.114.097030] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 03/24/2015] [Indexed: 01/14/2023] Open
Abstract
Biased agonism on the type I angiotensin receptor (AT1-R) can achieve different outcomes via activation of G protein-dependent and -independent cellular responses. In this study, we investigated whether the biased activation of AT1-R can lead to different regulation and intracellular processing of the receptor. We analyzed β-arrestin binding, endocytosis, and subsequent trafficking steps, such as early and late phases of recycling of AT1-R in human embryonic kidney 293 cells expressing wild-type or biased mutant receptors in response to different ligands. We used Renilla luciferase-tagged receptors and yellow fluorescent protein-tagged β-arrestin2, Rab5, Rab7, and Rab11 proteins in bioluminescence resonance energy transfer measurements to follow the fate of the receptor after stimulation. We found that not only is the signaling of the receptor different upon using selective ligands, but the fate within the cells is also determined by the type of the stimulation. β-arrestin binding and the internalization kinetics of the angiotensin II-stimulated AT1-R differed from those stimulated by the biased agonists. Similarly, angiotensin II-stimulated wild-type AT1-R showed differences compared with a biased mutant AT1-R (DRY/AAY AT1-R) with regards to β-arrestin binding and endocytosis. We found that the differences in the internalization kinetics of the receptor in response to biased agonist stimulation are due to the differences in plasma membrane phosphatidylinositol 4,5-bisphosphate depletion. Moreover, the stability of the β-arrestin binding is a major determinant of the later fate of the internalized AT1-R receptor.
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Affiliation(s)
- Gyöngyi Szakadáti
- Department of Physiology, Semmelweis University, Faculty of Medicine, Budapest, Hungary (G.S., A.D.T., I.O., L.S.E., P.V., L.H., A.B.), Magyar Tudományos Akadémia-Semmelweis Egyetem Laboratory of Molecular Physiology, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary (L.S.E., P.V., L.H., A.B.); and Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland (T.B.)
| | - András D Tóth
- Department of Physiology, Semmelweis University, Faculty of Medicine, Budapest, Hungary (G.S., A.D.T., I.O., L.S.E., P.V., L.H., A.B.), Magyar Tudományos Akadémia-Semmelweis Egyetem Laboratory of Molecular Physiology, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary (L.S.E., P.V., L.H., A.B.); and Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland (T.B.)
| | - Ilona Oláh
- Department of Physiology, Semmelweis University, Faculty of Medicine, Budapest, Hungary (G.S., A.D.T., I.O., L.S.E., P.V., L.H., A.B.), Magyar Tudományos Akadémia-Semmelweis Egyetem Laboratory of Molecular Physiology, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary (L.S.E., P.V., L.H., A.B.); and Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland (T.B.)
| | - László Sándor Erdélyi
- Department of Physiology, Semmelweis University, Faculty of Medicine, Budapest, Hungary (G.S., A.D.T., I.O., L.S.E., P.V., L.H., A.B.), Magyar Tudományos Akadémia-Semmelweis Egyetem Laboratory of Molecular Physiology, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary (L.S.E., P.V., L.H., A.B.); and Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland (T.B.)
| | - Tamas Balla
- Department of Physiology, Semmelweis University, Faculty of Medicine, Budapest, Hungary (G.S., A.D.T., I.O., L.S.E., P.V., L.H., A.B.), Magyar Tudományos Akadémia-Semmelweis Egyetem Laboratory of Molecular Physiology, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary (L.S.E., P.V., L.H., A.B.); and Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland (T.B.)
| | - Péter Várnai
- Department of Physiology, Semmelweis University, Faculty of Medicine, Budapest, Hungary (G.S., A.D.T., I.O., L.S.E., P.V., L.H., A.B.), Magyar Tudományos Akadémia-Semmelweis Egyetem Laboratory of Molecular Physiology, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary (L.S.E., P.V., L.H., A.B.); and Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland (T.B.)
| | - László Hunyady
- Department of Physiology, Semmelweis University, Faculty of Medicine, Budapest, Hungary (G.S., A.D.T., I.O., L.S.E., P.V., L.H., A.B.), Magyar Tudományos Akadémia-Semmelweis Egyetem Laboratory of Molecular Physiology, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary (L.S.E., P.V., L.H., A.B.); and Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland (T.B.)
| | - András Balla
- Department of Physiology, Semmelweis University, Faculty of Medicine, Budapest, Hungary (G.S., A.D.T., I.O., L.S.E., P.V., L.H., A.B.), Magyar Tudományos Akadémia-Semmelweis Egyetem Laboratory of Molecular Physiology, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary (L.S.E., P.V., L.H., A.B.); and Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland (T.B.)
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Gyombolai P, Tóth AD, Tímár D, Turu G, Hunyady L. Mutations in the 'DRY' motif of the CB1 cannabinoid receptor result in biased receptor variants. J Mol Endocrinol 2015; 54:75-89. [PMID: 25510402 DOI: 10.1530/jme-14-0219] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The role of the highly conserved 'DRY' motif in the signaling of the CB1 cannabinoid receptor (CB1R) was investigated by inducing single-, double-, and triple-alanine mutations into this site of the receptor. We found that the CB1R-R3.50A mutant displays a partial decrease in its ability to activate heterotrimeric Go proteins (∼80% of WT CB1R (CB1R-WT)). Moreover, this mutant showed an enhanced basal β-arrestin2 (β-arr2) recruitment. More strikingly, the double-mutant CB1R-D3.49A/R3.50A was biased toward β-arrs, as it gained a robustly increased β-arr1 and β-arr2 recruitment ability compared with the WT receptor, while its G-protein activation was decreased. In contrast, the double-mutant CB1R-R3.50A/Y3.51A proved to be G-protein-biased, as it was practically unable to recruit β-arrs in response to agonist stimulus, while still activating G-proteins, although at a reduced level (∼70% of CB1R-WT). Agonist-induced ERK1/2 activation of the CB1R mutants showed a good correlation with their β-arr recruitment ability but not with their G-protein activation or inhibition of cAMP accumulation. Our results suggest that G-protein activation and β-arr binding of the CB1R are mediated by distinct receptor conformations, and the conserved 'DRY' motif plays different roles in the stabilization of these conformations, thus mediating both G-protein- and β-arr-mediated functions of CB1R.
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Affiliation(s)
- Pál Gyombolai
- Department of PhysiologyFaculty of Medicine, Semmelweis University, PO Box 259, H-1444 Budapest, HungaryMTA-SE Laboratory of Molecular PhysiologyHungarian Academy of Sciences and Semmelweis University, Budapest, Hungary Department of PhysiologyFaculty of Medicine, Semmelweis University, PO Box 259, H-1444 Budapest, HungaryMTA-SE Laboratory of Molecular PhysiologyHungarian Academy of Sciences and Semmelweis University, Budapest, Hungary
| | - András D Tóth
- Department of PhysiologyFaculty of Medicine, Semmelweis University, PO Box 259, H-1444 Budapest, HungaryMTA-SE Laboratory of Molecular PhysiologyHungarian Academy of Sciences and Semmelweis University, Budapest, Hungary
| | - Dániel Tímár
- Department of PhysiologyFaculty of Medicine, Semmelweis University, PO Box 259, H-1444 Budapest, HungaryMTA-SE Laboratory of Molecular PhysiologyHungarian Academy of Sciences and Semmelweis University, Budapest, Hungary
| | - Gábor Turu
- Department of PhysiologyFaculty of Medicine, Semmelweis University, PO Box 259, H-1444 Budapest, HungaryMTA-SE Laboratory of Molecular PhysiologyHungarian Academy of Sciences and Semmelweis University, Budapest, Hungary
| | - László Hunyady
- Department of PhysiologyFaculty of Medicine, Semmelweis University, PO Box 259, H-1444 Budapest, HungaryMTA-SE Laboratory of Molecular PhysiologyHungarian Academy of Sciences and Semmelweis University, Budapest, Hungary Department of PhysiologyFaculty of Medicine, Semmelweis University, PO Box 259, H-1444 Budapest, HungaryMTA-SE Laboratory of Molecular PhysiologyHungarian Academy of Sciences and Semmelweis University, Budapest, Hungary
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Szalai B, Hoffmann P, Prokop S, Erdélyi L, Várnai P, Hunyady L. Improved methodical approach for quantitative BRET analysis of G Protein Coupled Receptor dimerization. PLoS One 2014; 9:e109503. [PMID: 25329164 PMCID: PMC4201472 DOI: 10.1371/journal.pone.0109503] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 09/11/2014] [Indexed: 01/22/2023] Open
Abstract
G Protein Coupled Receptors (GPCR) can form dimers or higher ordered oligomers, the process of which can remarkably influence the physiological and pharmacological function of these receptors. Quantitative Bioluminescence Resonance Energy Transfer (qBRET) measurements are the gold standards to prove the direct physical interaction between the protomers of presumed GPCR dimers. For the correct interpretation of these experiments, the expression of the energy donor Renilla luciferase labeled receptor has to be maintained constant, which is hard to achieve in expression systems. To analyze the effects of non-constant donor expression on qBRET curves, we performed Monte Carlo simulations. Our results show that the decrease of donor expression can lead to saturation qBRET curves even if the interaction between donor and acceptor labeled receptors is non-specific leading to false interpretation of the dimerization state. We suggest here a new approach to the analysis of qBRET data, when the BRET ratio is plotted as a function of the acceptor labeled receptor expression at various donor receptor expression levels. With this method, we were able to distinguish between dimerization and non-specific interaction when the results of classical qBRET experiments were ambiguous. The simulation results were confirmed experimentally using rapamycin inducible heterodimerization system. We used this new method to investigate the dimerization of various GPCRs, and our data have confirmed the homodimerization of V2 vasopressin and CaSR calcium sensing receptors, whereas our data argue against the heterodimerization of these receptors with other studied GPCRs, including type I and II angiotensin, β2 adrenergic and CB1 cannabinoid receptors.
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Affiliation(s)
- Bence Szalai
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
- MTA-SE Laboratory of Molecular Physiology, Budapest, Hungary
| | - Péter Hoffmann
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Susanne Prokop
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - László Erdélyi
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
- MTA-SE Laboratory of Molecular Physiology, Budapest, Hungary
| | - Péter Várnai
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
- MTA-SE Laboratory of Molecular Physiology, Budapest, Hungary
| | - László Hunyady
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
- MTA-SE Laboratory of Molecular Physiology, Budapest, Hungary
- * E-mail:
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Erdélyi LS, Balla A, Patócs A, Tóth M, Várnai P, Hunyady L. Altered agonist sensitivity of a mutant v2 receptor suggests a novel therapeutic strategy for nephrogenic diabetes insipidus. Mol Endocrinol 2014; 28:634-43. [PMID: 24628417 DOI: 10.1210/me.2013-1424] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Loss-of-function mutations of the type 2 vasopressin receptor (V2R) in kidney can lead to nephrogenic diabetes insipidus (NDI). We studied a previously described, but uncharacterized, mutation of the V2R (N321K missense mutation) of a patient with NDI. The properties of the mutant receptor were evaluated. We constructed a highly sensitive Epac-based bioluminescence resonance energy transfer biosensor to perform real-time cAMP measurements after agonist stimulation of transiently transfected HEK293 cells with V2Rs. β-Arrestin binding of the activated receptors was examined with luciferase-tagged β-arrestin and mVenus-tagged V2Rs using the bioluminescence resonance energy transfer technique. Cell surface expression levels of hemagglutinin-tagged receptors were determined with flow cytometry using anti-hemagglutinin-Alexa 488 antibodies. Cellular localization examinations were implemented with fluorescent tagged receptors visualized with confocal laser scanning microscopy. The effect of various vasopressin analogs on the type 1 vasopressin receptor (V1R) was tested on mouse arteries by wire myography. The N321K mutant V2R showed normal cell surface expression, but the potency of arginine vasopressin for cAMP generation was low, whereas the clinically used desmopressin was not efficient. The β-arrestin binding and internalization properties of the mutant receptor were also different than those for the wild type. The function of the mutant receptor can be rescued with administration of the V2R agonist Val(4)-desmopressin, which had no detectable side effects on V1R in the effective cAMP generating concentrations. Based on these findings we propose a therapeutic strategy for patients with NDI carrying the N321K mutation, as our in vivo experiments suggest that Val(4)-desmopressin could rescue the function of the N321K-V2R without significant side effects on the V1R.
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Affiliation(s)
- László Sándor Erdélyi
- Department of Physiology (L.S.E., A.B., P.V., L.H.), Faculty of Medicine, Semmelweis University, H-1094 Budapest, Hungary; MTA-SE Laboratory of Molecular Physiology (L.S.E., A.B., V.P., L.H.), Hungarian Academy of Sciences and Semmelweis University, H-1094 Budapest, Hungary; 2nd Department of Internal Medicine (A.P., M.T.), Faculty of Medicine, Semmelweis University, H-1094 Budapest, Hungary
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Gyombolai P, Boros E, Hunyady L, Turu G. Differential β-arrestin2 requirements for constitutive and agonist-induced internalization of the CB1 cannabinoid receptor. Mol Cell Endocrinol 2013; 372:116-27. [PMID: 23541635 DOI: 10.1016/j.mce.2013.03.013] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Revised: 02/06/2013] [Accepted: 03/15/2013] [Indexed: 01/13/2023]
Abstract
CB1 cannabinoid receptor (CB1R) undergoes both constitutive and agonist-induced internalization, but the underlying mechanisms of these processes and the role of β-arrestins in the regulation of CB1R function are not completely understood. In this study, we followed CB1R internalization using confocal microscopy and bioluminescence resonance energy transfer measurements in HeLa and Neuro-2a cells. We found that upon activation CB1R binds β-arrestin2 (β-arr2), but not β-arrestin1. Furthermore, both the expression of dominant-negative β-arr2 (β-arr2-V54D) and siRNA-mediated knock-down of β-arr2 impaired the agonist-induced internalization of CB1R. In contrast, neither β-arr2-V54D nor β-arr2-specific siRNA had a significant effect on the constitutive internalization of CB1R. However, both constitutive and agonist-induced internalization of CB1R were impaired by siRNA-mediated depletion of clathrin heavy chain. We conclude that although clathrin is required for both constitutive and agonist-stimulated internalization of CB1R, β-arr2 binding is only required for agonist-induced internalization of the receptor suggesting that the molecular mechanisms underlying constitutive and agonist-induced internalization of CB1R are different.
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Affiliation(s)
- Pál Gyombolai
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary.
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Arrestins in the cardiovascular system. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 118:297-334. [PMID: 23764059 DOI: 10.1016/b978-0-12-394440-5.00012-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Of the four mammalian arrestins, only the β-arrestins (βarrs; Arrestin2 and -3) are expressed throughout the cardiovascular system, where they regulate, as either desensitizers/internalizers or signal transducers, several G-protein-coupled receptors (GPCRs) critical for cardiovascular homeostasis. The cardiovascular roles of βarrs have been delineated at an accelerated pace via a variety of techniques and tools, such as knockout mice, siRNA knockdown, artificial or naturally occurring polymorphic GPCRs, and availability of new βarr "biased" GPCR ligands. This chapter summarizes the current knowledge of cardiovascular arrestin physiology and pharmacology, addressing the individual cardiovascular receptors affected by βarrs in vivo, as well as the individual cell types, tissues, and organs of the cardiovascular system in which βarr effects are exerted; for example, cardiac myocyte or fibroblast, vascular smooth muscle, adrenal gland and platelet. In the broader scope of cardiovascular βarr pharmacology, a discussion of the βarr "bias" of certain cardiovascular GPCR ligands is also included.
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Johnstone EKM, Pfleger KDG. Receptor-Heteromer Investigation Technology and its application using BRET. Front Endocrinol (Lausanne) 2012; 3:101. [PMID: 22936924 PMCID: PMC3424490 DOI: 10.3389/fendo.2012.00101] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Accepted: 08/04/2012] [Indexed: 01/08/2023] Open
Abstract
Receptor heteromerization has the potential to alter every facet of receptor functioning, leading to new pharmacological profiles with increased signaling diversity and regulation from that of the monomeric receptor, or indeed receptor homomer. An understanding of the molecular consequences of receptor heteromerization will provide new insights into the physiology and pathology mediated by receptors, expanding the possibilities for pharmacological discovery. Particularly advantageous approaches to investigate novel heteromer pharmacology utilize cell-based assay technologies that assess ligand-dependent functional responses specific to the receptor heteromer. Importantly, this allows for differentiation of heteromer-specific pharmacology from pharmacology associated with the co-expressed receptor monomers and homomers. The Receptor-Heteromer Investigation Technology (Receptor-HIT) successfully employs a proximity-based reporter system, such as bioluminescence resonance energy transfer (BRET), in a configuration that enables determination of such heteromer-specific pharmacology. Therefore, Receptor-HIT provides a simple, robust and versatile approach for investigating the elusive "biochemical fingerprint" of receptor heteromers.
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Affiliation(s)
- Elizabeth K. M. Johnstone
- Laboratory for Molecular Endocrinology – GPCRs, Western Australian Institute for Medical Research and Centre for Medical Research, The University of Western AustraliaPerth, WA, Australia
| | - Kevin D. G. Pfleger
- Laboratory for Molecular Endocrinology – GPCRs, Western Australian Institute for Medical Research and Centre for Medical Research, The University of Western AustraliaPerth, WA, Australia
- Dimerix Bioscience Pty LtdPerth, WA, Australia
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Pijacka W, Hunter MG, Broughton Pipkin F, Luck MR. Expression of renin-angiotensin system components in the early bovine embryo. Endocr Connect 2012; 1:22-30. [PMID: 23781300 PMCID: PMC3681317 DOI: 10.1530/ec-12-0013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Accepted: 05/14/2012] [Indexed: 11/30/2022]
Abstract
The renin-angiotensin system (RAS), mainly associated with the regulation of blood pressure, has been recently investigated in female reproductive organs and the developing foetus. Angiotensin II (Ang II) influences oviductal gamete movements and foetal development, but there is no information about RAS in the early embryo. The aim of this study was to determine whether RAS components are present in the pre-implantation embryo, to determine how early they are expressed and to investigate their putative role at this stage of development. Bovine embryos produced in vitro were used for analysis of RAS transcripts (RT-PCR) and localisation of the receptors AGTR1 and AGTR2 (immunofluorescent labelling). We also investigated the effects of Ang II, Olmesartan (AGTR1 antagonist) and PD123319 (AGTR2 antagonist) on oocyte cleavage, embryo expansion and hatching. Pre-implanted embryos possessed AGTR1 and AGTR2 but not the other RAS components. Both receptors were present in the trophectoderm and in the inner cell mass of the blastocyst. AGTR1 was mainly localised in granular-like structures in the cytoplasm, suggesting its internalisation into clathrin-coated vesicles, and AGTR2 was found mainly in the nuclear membrane and in the mitotic spindle of dividing trophoblastic cells. Treating embryos with PD123319 increased the proportion of hatched embryos compared with the control. These results, the first on RAS in the early embryo, suggest that the pre-implanted embryo responds to Ang II from the mother rather than from the embryo itself. This may be a route by which the maternal RAS influences blastocyst hatching and early embryonic development.
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Affiliation(s)
| | | | - Fiona Broughton Pipkin
- New Maternity UnitNottingham University Hospitals NHS TrustCity Hospital Campus, Hucknall Road, Nottingham, NG5 1PBUK
| | - Martin R Luck
- Correspondence should be addressed to M R Luck Email
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Szalai B, Barkai L, Turu G, Szidonya L, Várnai P, Hunyady L. Allosteric interactions within the AT₁ angiotensin receptor homodimer: role of the conserved DRY motif. Biochem Pharmacol 2012; 84:477-85. [PMID: 22579851 DOI: 10.1016/j.bcp.2012.04.014] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 04/15/2012] [Accepted: 04/18/2012] [Indexed: 12/20/2022]
Abstract
G protein coupled receptor (GPCR) dimerization has a remarkable impact on the diversity of receptor signaling. Allosteric communication between the protomers of the dimer can alter ligand binding, receptor conformation and interactions with different effector proteins. In this study we investigated the allosteric interactions between wild type and mutant protomers of type 1 angiotensin receptor (AT₁R) dimers transiently expressed in CHO cells. In our experimental setup, one protomer of the dimer was selectively stimulated and the β-arrestin2 binding and conformation alteration of the other protomer was followed. The interaction between β-arrestin2 and the non-stimulated protomer was monitored through a bioluminescence resonance energy transfer (BRET) based method. To measure the conformational alterations in the non-stimulated protomer directly, we also used a BRET based intramolecular receptor biosensor, which was created by inserting yellow fluorescent protein (YFP) into the 3rd intracellular loop of AT₁R and fusing Renilla luciferase (RLuc) to its C terminal region. We have detected β-arrestin2 binding, and altered conformation of the non-stimulated protomer. The cooperative ligand binding of the receptor homodimer was also observed by radioligand dissociation experiments. Mutation of the conserved DRY sequence in the activated protomer, which is also required for G protein activation, abolished all the observed allosteric effects. These data suggest that allosteric interactions in the homodimers of AT₁R significantly affect the function of the non-stimulated protomer, and the conserved DRY motif has a crucial role in these interactions.
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Affiliation(s)
- Bence Szalai
- Department of Physiology, Semmelweis University, Faculty of Medicine, Budapest, Hungary
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36
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Tóth DJ, Tóth JT, Gulyás G, Balla A, Balla T, Hunyady L, Várnai P. Acute depletion of plasma membrane phosphatidylinositol 4,5-bisphosphate impairs specific steps in endocytosis of the G-protein-coupled receptor. J Cell Sci 2012; 125:2185-97. [PMID: 22357943 DOI: 10.1242/jcs.097279] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Receptor endocytosis plays an important role in regulating the responsiveness of cells to specific ligands. Phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P(2)] has been shown to be crucial for endocytosis of some cell surface receptors, such as EGF and transferrin receptors, but its role in G-protein-coupled receptor internalization has not been investigated. By using luciferase-labeled type 1 angiotensin II (AT1R), type 2C serotonin (5HT2CR) or β(2) adrenergic (β2AR) receptors and fluorescently tagged proteins (β-arrestin-2, plasma-membrane-targeted Venus, Rab5) we were able to follow the sequence of molecular interactions along the endocytic route of the receptors in HEK293 cells using the highly sensitive method of bioluminescence resonance energy transfer and confocal microscopy. To study the role of plasma membrane PtdIns(4,5)P(2) in receptor endocytosis, we used our previously developed rapamycin-inducible heterodimerization system, in which the recruitment of a 5-phosphatase domain to the plasma membrane degrades PtdIns(4,5)P(2). Here we show that ligand-induced interaction of AT1, 5HT2C and β(2)A receptors with β-arrestin-2 was unaffected by PtdIns(4,5)P(2) depletion. However, trafficking of the receptors to Rab5-positive early endosomes was completely abolished in the absence of PtdIns(4,5)P(2). Remarkably, removal of the receptors from the plasma membrane was reduced but not eliminated after PtdIns(4,5)P(2) depletion. Under these conditions, stimulated AT1 receptors clustered along the plasma membrane, but did not enter the cells. Our data suggest that in the absence of PtdIns(4,5)P(2), these receptors move into clathrin-coated membrane structures, but these are not cleaved efficiently and hence cannot reach the early endosomal compartment.
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Affiliation(s)
- Dániel J Tóth
- Department of Physiology, Semmelweis University, Faculty of Medicine, Budapest, Hungary
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Balla A, Tóth DJ, Soltész-Katona E, Szakadáti G, Erdélyi LS, Várnai P, Hunyady L. Mapping of the localization of type 1 angiotensin receptor in membrane microdomains using bioluminescence resonance energy transfer-based sensors. J Biol Chem 2012; 287:9090-9. [PMID: 22291018 DOI: 10.1074/jbc.m111.293944] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Initiation and termination of signaling of the type I angiotensin receptor (AT(1)-R) can lead to dynamic changes in its localization in plasma membrane microdomains. Several markers were recently developed to investigate membrane microdomains. Here, we used several YFP-labeled fusion constructs (i.e. raft or non-raft plasma membrane markers) to analyze the agonist-induced changes in compartmentalization of AT(1)-R, including internalization or lateral movement between plasma membrane compartments in response to stimulation using bioluminescence resonance energy transfer measurements. Our data demonstrate that angiotensin II (AngII) stimulus changes the microdomain localization of wild type or mutated (DRY → AAY or TSTS → AAAA) AT(1)-Rs co-expressed with the fluorescent probes in HEK293 cells. The comparison of the trafficking of AT(1)-R upon AngII stimulus with those of [Sar(1),Ile(8)]AngII or [Sar(1),Ile(4),Ile(8)]AngII stimulus revealed different types of changes, depending on the nature of the ligand. The observed changes in receptor compartmentalization of the AT(1)-R are strikingly different from those of 5HT-2C and EGF receptors, which demonstrate the usefulness of the bioluminescence resonance energy transfer-based measurements in the investigation of receptor trafficking in the plasma membrane in living cell experiments.
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Affiliation(s)
- András Balla
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
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38
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Abstract
The title of the proposed series of reviews is Translational Success Stories. The definition of "translation" according to Webster is, "an act, process, or instance of translating as a rendering of one language into another." In the context of this inaugural review, it is the translation of Tigerstedt's and Bergman's(1) discovery in 1898 of the vasoconstrictive effects of an extract of rabbit kidney to the treatment of heart failure. As recounted by Marks and Maxwell,(2) their discovery was heavily influenced by the original experiments of the French physiologist Brown-Séquard, who was the author of the doctrine that "many organs dispense substances into the blood which are not ordinary waste products, but have specific functions." They were also influenced by Bright's(3) original observation that linked kidney disease with hypertension with the observation that patients dying with contracted kidneys often exhibited a hard, full pulse and cardiac hypertrophy. However, from Tigerstedt's initial discovery, there was a long and arduous transformation of ideas and paradigms that eventually translated to clinical applications. Although the role of the renin-angiotensin system in the pathophysiology of hypertension and heart failure was suspected through the years, beneficial effects from its blockade were not realized until the early 1970s. Thus, this story starts with a short historical perspective that provides the reader some insight and appreciation into the long delay in translation.
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Affiliation(s)
- Louis J Dell'Italia
- Birmingham Veteran Affairs Medical Center, Department of Medicine, Division of Cardiovascular Disease, University Station, University of Alabama, Birmingham, USA.
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Porrello ER, Pfleger KDG, Seeber RM, Qian H, Oro C, Abogadie F, Delbridge LMD, Thomas WG. Heteromerization of angiotensin receptors changes trafficking and arrestin recruitment profiles. Cell Signal 2011; 23:1767-76. [PMID: 21740964 DOI: 10.1016/j.cellsig.2011.06.011] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2011] [Revised: 05/29/2011] [Accepted: 06/15/2011] [Indexed: 10/18/2022]
Abstract
The cardiovascular hormone angiotensin II (AngII) exerts its actions via two G protein-coupled receptor (GPCR) subtypes, AT(1) and AT(2), which often display antagonistic functions. Methodological constraints have so far precluded detailed analyses of the ligand-dependency, cellular localization, and functional relevance of AngII receptor interactions in live cells. In this study, we utilize a protein-fragment complementation assay (PCA) and GPCR-Heteromer Identification Technology (GPCR-HIT) to provide the first detailed investigation of the ligand-dependency and cellular localization of AngII receptor interactions in human embryonic kidney 293 cells. Fluorescent-tagged receptor constructs for PCA and GPCR-HIT displayed normal affinity and selectivity for AngII (AT(1): IC(50)=1.0-1.6nM; AT(2): IC(50)=2.0-3.0nM). Well-characterized angiotensin receptor interactions were used as positive and negative controls to demonstrate the sensitivity and specificity of these fluorescence-based assays. We report that AT(1)-AT(2) receptor heteromers form constitutively, are localized to the plasma membrane and perinuclear compartments, and do not internalize following AngII stimulation despite arrestin being recruited specifically to the heteromer. Our findings using novel fluorescence-based technologies reveal a previously unrecognized mechanism of angiotensin receptor cross-talk involving cross-inhibition of AT(1) receptor internalization through heteromerization with the AT(2) receptor subtype.
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Affiliation(s)
- Enzo R Porrello
- Department of Physiology, The University of Melbourne, Victoria 3010, Australia.
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40
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Orenes-Piñero E, Hernández-Romero D, Jover E, Valdés M, Lip GYH, Marín F. Impact of polymorphisms in the renin–angiotensin–aldosterone system on hypertrophic cardiomyopathy. J Renin Angiotensin Aldosterone Syst 2011; 12:521-30. [DOI: 10.1177/1470320311405247] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is a clinically heterogeneous autosomal dominant heart disease characterised by left ventricular hypertrophy in the absence of another cardiac or systemic disease that is capable of producing significant wall thickening. Microscopically it is characterised by cardiomyocyte hypertrophy, myofibrillar disarray and fibrosis. The phenotypic expression of HCM is multifactorial, with the majority of cases occurring secondary to mutations in genes encoding the sarcomere proteins. In conjunction with the genetic heterogeneity of HCM, phenotypic expression also exhibits a high level of variability even within families with the same aetiological mutation, and may be influenced by additional genetic factors. Polymorphisms of the renin–angiotensin–aldosterone system (RAAS) represent an attractive hypothesis as potential disease modifiers, as these genetic variants alter the ‘activation status’ of the RAAS, which leads to more left ventricular hypertrophy through different pathways. The main objective of this review is to provide an overview of the role of different polymorphisms identified in the RAAS, in patients with HCM.
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Affiliation(s)
- Esteban Orenes-Piñero
- Department of Cardiology, Hospital Universitario Virgen de la Arrixaca, Murcia, Spain
| | | | - Eva Jover
- Department of Cardiology, Hospital Universitario Virgen de la Arrixaca, Murcia, Spain
| | - Mariano Valdés
- Department of Cardiology, Hospital Universitario Virgen de la Arrixaca, Murcia, Spain
| | - Gregory YH Lip
- Haemostasis, Thrombosis and Vascular Biology Unit, University of Birmingham Centre for Cardiovascular Sciences, City Hospital, Birmingham, UK
| | - Francisco Marín
- Department of Cardiology, Hospital Universitario Virgen de la Arrixaca, Murcia, Spain
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Spooren A, Rondou P, Debowska K, Lintermans B, Vermeulen L, Samyn B, Skieterska K, Debyser G, Devreese B, Vanhoenacker P, Wojda U, Haegeman G, Van Craenenbroeck K. Resistance of the dopamine D4 receptor to agonist-induced internalization and degradation. Cell Signal 2010; 22:600-9. [DOI: 10.1016/j.cellsig.2009.11.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2009] [Revised: 11/12/2009] [Accepted: 11/16/2009] [Indexed: 02/04/2023]
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42
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Turu G, Várnai P, Gyombolai P, Szidonya L, Offertaler L, Bagdy G, Kunos G, Hunyady L. Paracrine transactivation of the CB1 cannabinoid receptor by AT1 angiotensin and other Gq/11 protein-coupled receptors. J Biol Chem 2009; 284:16914-16921. [PMID: 19357084 DOI: 10.1074/jbc.m109.003681] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Intracellular signaling systems of G protein-coupled receptors are well established, but their role in paracrine regulation of adjacent cells is generally considered as a tissue-specific mechanism. We have shown previously that AT(1) receptor (AT(1)R) stimulation leads to diacylglycerol lipase-mediated transactivation of co-expressed CB(1)Rs in Chinese hamster ovary cells. In the present study we detected a paracrine effect of the endocannabinoid release from Chinese hamster ovary, COS7, and HEK293 cells during the stimulation of AT(1) angiotensin receptors by determining CB(1) cannabinoid receptor activity with bioluminescence resonance energy transfer-based sensors of G protein activation expressed in separate cells. The angiotensin II-induced, paracrine activation of CB(1) receptors was visualized by detecting translocation of green fluorescent protein-tagged beta-arrestin2. Mass spectrometry analyses have demonstrated angiotensin II-induced stimulation of 2-arachidonoylglycerol production, whereas no increase of anandamide levels was observed. Stimulation of G(q/11)-coupled M(1), M(3), M(5) muscarinic, V(1) vasopressin, alpha(1a) adrenergic, B(2) bradykinin receptors, but not G(i/o)-coupled M(2) and M(4) muscarinic receptors, also led to paracrine transactivation of CB(1) receptors. These data suggest that, in addition to their retrograde neurotransmitter role, endocannabinoids have much broader paracrine mediator functions during activation of G(q/11)-coupled receptors.
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Affiliation(s)
- Gábor Turu
- From the Department of Physiology, Faculty of Medicine, Budapest, Hungary
| | - Péter Várnai
- From the Department of Physiology, Faculty of Medicine, Budapest, Hungary
| | - Pál Gyombolai
- From the Department of Physiology, Faculty of Medicine, Budapest, Hungary
| | - László Szidonya
- From the Department of Physiology, Faculty of Medicine, Budapest, Hungary
| | - László Offertaler
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, Bethesda, Maryland 20892-9413
| | - György Bagdy
- Department of Pharmacodynamics, Faculty of Pharmacy, Semmelweis University, Budapest, Hungary; Group of Neuropsychopharmacology, Semmelweis University and Hungarian Academy of Sciences, Budapest, Hungary
| | - George Kunos
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, Bethesda, Maryland 20892-9413
| | - László Hunyady
- From the Department of Physiology, Faculty of Medicine, Budapest, Hungary; Laboratory of Neurobiochemistry and Molecular Physiology, Budapest, Hungary.
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Thieme K, Eguti DMN, Mello-Aires M, Oliveira-Souza M. The effect of angiotensin II on intracellular pH is mediated by AT1receptor translocation. Am J Physiol Cell Physiol 2008; 295:C138-45. [DOI: 10.1152/ajpcell.00512.2007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effect of ANG II on intracellular pH (pHi) recovery rate and AT1receptor translocation was investigated in transfected MDCK cells. The pHirecovery rate was evaluated by fluorescence microscopy using the fluorescent probe BCECF-AM. The human angiotensin II receptor isoform 1 (hAT1) translocation was analyzed by immunofluorescence and confocal microscope. Our data show that transfected cells in control situation have a pHirecovery rate of 0.219 ± 0.017 pH U/min ( n = 11). This value was similar to nontransfected cells [0.211 ± 0.009 pH U/min ( n = 12)]. Both values were significantly increased with ANG II (10−9M) but not with ANG II (10−6M). Losartan (10−7M) and dimethyl-BAPTA-AM (10−7M) decreased significantly the stimulatory effect of ANG II (10−9M) and induced an increase in Na+/H+exchanger 1 (NHE-1) activity with ANG II (10−6M). Immunofluorescence studies indicated that in control situation, the hAT1receptor was predominantly expressed in cytosol. However, it was translocated to plasma membrane with ANG II (10−9M) and internalized with ANG II (10−6M). Losartan (10−7M) induced hAT1translocation to plasma membrane in all studied groups. Dimethyl-BAPTA-AM (10−7M) did not change the effect of ANG II (10−9M) on the hAT1receptor distribution but induced its accumulation at plasma membrane in cells treated with ANG II (10−6M). With ionomycin (10−6M), the receptor was accumulated in cytosol. The results indicate that, in MDCK cells, the effect of ANG II on NHE-1 activity is associated with ligand binding to AT1receptor and intracellular signaling events related to AT1translocation.
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Schlüter KD, Wenzel S. Angiotensin II: a hormone involved in and contributing to pro-hypertrophic cardiac networks and target of anti-hypertrophic cross-talks. Pharmacol Ther 2008; 119:311-25. [PMID: 18619489 DOI: 10.1016/j.pharmthera.2008.05.010] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2008] [Accepted: 05/30/2008] [Indexed: 12/23/2022]
Abstract
Angiotensin II (Ang II) plays a major role in the progression of myocardial hypertrophy to heart failure. Inhibiting the angiotensin converting enzyme (ACE) or blockade of the corresponding Ang II receptors is used extensively in clinical practice, but there is scope for refinement of this mode of therapy. This review summarizes the current understanding of the direct effects of Ang II on cardiomyocytes and then focus particularly on interaction of components of the renin-angiotensin system with other hormones and cytokines. New findings described in approximately 400 papers identified in the PubMed database and published during the 2.5 years are discussed in the context of previous relevant literature. The cardiac action of Ang II is influenced by the activity of different isoforms of ACE leading to different amounts of Ang II by comparison with other angiotensinogen-derived peptides. The effect of Ang II is mediated by at least two different AT receptors that are differentially expressed in cardiomyocytes from neonatal, adult and failing hearts. The intracellular effects of Ang II are influenced by nitric oxide (NO)/cGMP-dependent cross talk and are mediated by the release of autocrine factors, such as transforming growth factor (TGF)-beta1 and interleukin (IL)-6. Besides interactions with cytokines, Ang II is involved in systemic networks including aldosterone, parathyroid hormone and adrenomedullin, which have their own effects on cardiomyocytes that modify, amplify or antagonize the primary effect of Ang II. Finally, hyperinsulemia and hyperglycaemia influence Ang II-dependent processes in diabetes and its cardiac sequelae.
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Affiliation(s)
- K-D Schlüter
- Physiologisches Institut, Justus-Liebig-Universität Giessen, Germany.
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45
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Whitaker RD, Walt DR. Multianalyte Single-Cell Analysis with Multiple Cell Lines Using a Fiber-Optic Array. Anal Chem 2007; 79:9045-53. [DOI: 10.1021/ac701744x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ragnhild D. Whitaker
- Chemistry Department, Tufts University, 62 Talbot Avenue, Medford, Massachusetts 02155
| | - David R. Walt
- Chemistry Department, Tufts University, 62 Talbot Avenue, Medford, Massachusetts 02155
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46
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Potapova IA, Cohen IS, Doronin SV. Voltage-gated ion channel Kv4.3 is associated with Rap guanine nucleotide exchange factors and regulates angiotensin receptor type 1 signaling to small G-protein Rap. FEBS J 2007; 274:4375-84. [PMID: 17725712 DOI: 10.1111/j.1742-4658.2007.05966.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The voltage-gated potassium channel Kv4.3 was coexpressed with its beta-subunit Kv channel-interacting protein 2 and the angiotensin type 1 receptor in HEK-293 cells. Proteomic analysis of proteins coimmunoprecipitated with Kv4.3 revealed that Kv4.3 is associated with Rap guanine nucleotide exchange factors MR-GEF and EPAC-1. Previously, we demonstrated that Kv4.3 interacts with the angiotensin type 1 receptor in HE293 cells and cardiac myocytes. On the basis of this, we investigated the angiotensin type 1 receptor signaling to small G-proteins Ras and Rap-1 in the presence and absence of the Kv4.3-Kv channel-interacting protein 2 macromolecular complex. Ras activation was not significantly affected by coexpression of Kv4.3 and Kv channel-interacting protein 2. Ras exhibited a rapid activation-inactivation pattern with maximum activity at 2.5 min after addition of angiotensin II. In contrast, activation of Rap-1 was affected dramatically by coexpression of Kv4.3 and Kv channel-interacting protein 2 with the angiotensin type 1 receptor. In the absence of Kv4.3 and Kv channel-interacting protein 2, stimulation of the angiotensin type 1 receptor resulted in steady activation of Rap-1 that reached a plateau 25 min after addition of angiotensin II. In the presence of Kv4.3 and Kv channel-interacting protein 2, Rap-1 reaches a maximum activity 2.5 min after addition of angiotensin II and then deactivates rapidly, demonstrating a pattern of activation similar to that of Ras. Our findings show that Kv4.3 regulates angiotensin type 1 receptor signaling to the small G-protein Rap-1.
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Affiliation(s)
- Irina A Potapova
- Department of Physiology and Biophysics, Institute of Molecular Cardiology, State University of New York at Stony Brook, Stony Brook, NY 11794, USA
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47
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The effect of angiotensin II and IV on ERK1/2 and CREB signalling in cultured rat astroglial cells. Naunyn Schmiedebergs Arch Pharmacol 2007; 376:157-63. [PMID: 17952409 DOI: 10.1007/s00210-007-0192-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2007] [Accepted: 09/17/2007] [Indexed: 12/22/2022]
Abstract
Angiotensin peptides produced by the brain renin-angiotensin system have established roles in cognition, but there is no mechanistic basis of angiotensin effects on memory. Astroglial cells present throughout the whole brain, synthesize all the components of the renin-angiotensin system and express angiotensin receptors; therefore our aim was to assess changes in intracellular signalling pathways related to memory formation, particularly the activation of CREB and ERK1/2 in astroglial cells grown in the presence of angiotensin peptides. Cultured rat astroglial cells were treated for 24 h with 10 microM angiotensin II and/or 10 microM angiotensin IV in the presence or absence of 100 microM losartan (AT1-receptor antagonist) or 100 microM PD123319 (AT2-receptor antagonist). Both angiotensin peptides alone were without effect on culture protein levels and cell viability and did not induce oxidative stress, but both peptides together slightly elevated cell growth rates and increased damaged, apoptotic cell numbers. This effect was most probably mediated by the AT1 receptor. Angiotensin II but not angiotensin IV increased intracellular calcium via activation of AT1 receptor. Angiotensin IV but not angiotensin II increased extracellular-regulated protein kinases 1 and 2 (ERK1/2) by 65% and T202, T204 phosphorylated ERK1/2 levels by 36%; this effect was blocked in part by both losartan and PD123319. Angiotensin II but not angiotensin IV increased cyclic AMP-responsive element binding protein (CREB) expression by almost 100% and elevated Ser 133-phosphorylated CREB levels by 56%. These effects were also inhibited in part by both losartan and PD123319. Our results indicate that CREB activation in cultured rat glial cells is mediated mostly by angiotensin II. Angiotensin IV appears to affect the ERK1/2 pathway.
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48
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Oliveira L, Costa-Neto CM, Nakaie CR, Schreier S, Shimuta SI, Paiva ACM. The Angiotensin II AT1 Receptor Structure-Activity Correlations in the Light of Rhodopsin Structure. Physiol Rev 2007; 87:565-92. [PMID: 17429042 DOI: 10.1152/physrev.00040.2005] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The most prevalent physiological effects of ANG II, the main product of the renin-angiotensin system, are mediated by the AT1 receptor, a rhodopsin-like AGPCR. Numerous studies of the cardiovascular effects of synthetic peptide analogs allowed a detailed mapping of ANG II's structural requirements for receptor binding and activation, which were complemented by site-directed mutagenesis studies on the AT1 receptor to investigate the role of its structure in ligand binding, signal transduction, phosphorylation, binding to arrestins, internalization, desensitization, tachyphylaxis, and other properties. The knowledge of the high-resolution structure of rhodopsin allowed homology modeling of the AT1 receptor. The models thus built and mutagenesis data indicate that physiological (agonist binding) or constitutive (mutated receptor) activation may involve different degrees of expansion of the receptor's central cavity. Residues in ANG II structure seem to control these conformational changes and to dictate the type of cytosolic event elicited during the activation. 1) Agonist aromatic residues (Phe8 and Tyr4) favor the coupling to G protein, and 2) absence of these residues can favor a mechanism leading directly to receptor internalization via phosphorylation by specific kinases of the receptor's COOH-terminal Ser and Thr residues, arrestin binding, and clathrin-dependent coated-pit vesicles. On the other hand, the NH2-terminal residues of the agonists ANG II and [Sar1]-ANG II were found to bind by two distinct modes to the AT1 receptor extracellular site flanked by the COOH-terminal segments of the EC-3 loop and the NH2-terminal domain. Since the [Sar1]-ligand is the most potent molecule to trigger tachyphylaxis in AT1 receptors, it was suggested that its corresponding binding mode might be associated with this special condition of receptors.
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Affiliation(s)
- Laerte Oliveira
- Department of Biophysics, Escola Paulista de Medicina, Federal University of São Paulo, Brazil.
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49
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Turu G, Simon A, Gyombolai P, Szidonya L, Bagdy G, Lenkei Z, Hunyady L. The role of diacylglycerol lipase in constitutive and angiotensin AT1 receptor-stimulated cannabinoid CB1 receptor activity. J Biol Chem 2007; 282:7753-7. [PMID: 17227758 DOI: 10.1074/jbc.c600318200] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The cannabinoid CB1 receptor (CB1R) is a G protein-coupled receptor, which couples to the Gi/o family of heterotrimeric G proteins. The receptor displays both basal and agonist-induced signaling and internalization. Although basal activity of CB1Rs is attributed to constitutive (agonist-independent) receptor activity, studies in neurons suggested a role of postsynaptic endocannabinoid (eCB) release in the persistent activity of presynaptic CB1Rs. To elucidate the role of eCBs in basal CB1R activity, we have investigated the role of diacylglycerol lipase (DAGL) in this process in Chinese hamster ovary (CHO) cells, which are not targeted specifically with eCBs. Agonist-induced G protein activation was determined by detecting dissociation G protein subunits expressed in CHO cells with bioluminescence resonance energy transfer (BRET), after labeling the alpha and beta subunits with Renilla luciferase and enhanced yellow fluorescent protein (EYFP), respectively. Preincubation of the cells with tetrahydrolipstatin (THL), a known inhibitor of DAGLs, caused inhibition of the basal activity of CB1R. Moreover, preincubation of CHO and cultured hippocampal neurons with THL increased the number of CB1Rs on the cell membrane, which reflects its inhibitory action on CB1R internalization in non-simulated cells. In CHO cells co-expressing CB1R and angiotensin AT1 receptors, angiotensin II-induced Go protein activation that was blocked by both a CB1R antagonist and THL. These data indicate that cell-derived eCB mediators have a general role in the basal activity of CB1Rs in non-neural cells and neurons, and that this mechanism can be stimulated by AT1 receptor activation.
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Affiliation(s)
- Gábor Turu
- Department of Physiology, Semmelweis University, Faculty of Medicine, H-1444 Budapest, Hungary
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50
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Szidonya L, Süpeki K, Karip E, Turu G, Várnai P, Clark AJL, Hunyady L. AT1 receptor blocker-insensitive mutant AT1A angiotensin receptors reveal the presence of G protein-independent signaling in C9 cells. Biochem Pharmacol 2007; 73:1582-92. [PMID: 17284329 DOI: 10.1016/j.bcp.2007.01.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2006] [Revised: 12/28/2006] [Accepted: 01/03/2007] [Indexed: 01/01/2023]
Abstract
Although mutant receptors are highly useful to dissect the signal transduction pathways of receptors, they are difficult to study in physiological target tissues, due to the presence of endogenous receptors. To study AT(1) angiotensin receptors in their physiological environment, we constructed a mutant receptor, which differs only from the AT(1A) receptor in its reduced affinity for candesartan, a biphenylimidazole antagonist. We have determined that the conserved S109Y substitution of the rat AT(1A) receptor eliminates its candesartan binding, without exerting any major effect on its angiotensin II and peptide angiotensin receptor antagonist binding, internalization kinetics, beta-arrestin binding, and potency or efficacy of the inositol phosphate response. To demonstrate the usefulness of this mutant receptor in signal transduction studies, we combined it with substitution of the highly conserved DRY sequence with AAY, which abolishes G protein activation. In rat C9 hepatocytes the S109Y receptor caused ERK activation with the same mechanism as the endogenous AT(1) receptor. After combination with the DRY/AAY mutation G protein-independent ERK activation was detected demonstrating that this approach can be used to study the angiotensin II-stimulated signaling pathways in cells endogenously expressing AT(1) receptors.
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Affiliation(s)
- László Szidonya
- Department of Physiology, Semmelweis University, Budapest, Hungary
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