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Møller TC, Moo EV, Inoue A, Pedersen MF, Bräuner-Osborne H. Characterization of the real-time internalization of nine GPCRs reveals distinct dependence on arrestins and G proteins. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119584. [PMID: 37714305 DOI: 10.1016/j.bbamcr.2023.119584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 08/24/2023] [Accepted: 09/06/2023] [Indexed: 09/17/2023]
Abstract
G protein-coupled receptors (GPCRs) are seven transmembrane receptors that respond to external stimuli and undergo conformational changes to activate G proteins and modulate cellular processes leading to biological outcomes. To prevent overstimulation and prolonged exposure to stimuli, GPCRs are regulated by internalization. While the canonical GPCR internalization mechanism in mammalian cells is arrestin-dependent, clathrin-mediated endocytosis, more diverse GPCR internalization mechanisms have been described over the years. However, there is a lack of consistent methods used in the literature making it complicated to determine a receptor's internalization pathway. Here, we utilized a highly efficient time-resolved Förster resonance energy transfer (TR-FRET) internalization assay to determine the internalization profile of nine distinct GPCRs representing the GPCR classes A, B and C and with different G protein coupling profiles. This technique, coupled with clustered regularly interspaced palindromic repeats (CRISPR) engineered knockout cells allows us to effectively study the involvement of heterotrimeric G proteins and non-visual arrestins. We found that all the nine receptors internalized upon agonist stimulation in a concentration-dependent manner and six receptors showed basal internalization. Yet, there is no correlation between the receptor class and primary G protein coupling to the arrestin and G protein dependence for GPCR internalization. Overall, this study presents a platform for studying internalization that is applicable to most GPCRs and may even be extended to other membrane proteins. This method can be easily applicable to other endocytic machinery of interest and ultimately will lend itself towards the construction of comprehensive receptor internalization profiles.
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Affiliation(s)
- Thor C Møller
- Department of Drug Design and Pharmacology, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Ee Von Moo
- Department of Drug Design and Pharmacology, University of Copenhagen, 2100 Copenhagen, Denmark.
| | - Asuka Inoue
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Mie F Pedersen
- Department of Drug Design and Pharmacology, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Hans Bräuner-Osborne
- Department of Drug Design and Pharmacology, University of Copenhagen, 2100 Copenhagen, Denmark
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2
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Devaux CA, Lagier JC. Unraveling the Underlying Molecular Mechanism of 'Silent Hypoxia' in COVID-19 Patients Suggests a Central Role for Angiotensin II Modulation of the AT1R-Hypoxia-Inducible Factor Signaling Pathway. J Clin Med 2023; 12:jcm12062445. [PMID: 36983445 PMCID: PMC10056466 DOI: 10.3390/jcm12062445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 03/17/2023] [Accepted: 03/20/2023] [Indexed: 03/30/2023] Open
Abstract
A few days after being infected with SARS-CoV-2, a fraction of people remain asymptomatic but suffer from a decrease in arterial oxygen saturation in the absence of apparent dyspnea. In light of our clinical investigation on the modulation of molecules belonging to the renin angiotensin system (RAS) in COVID-19 patients, we propose a model that explains 'silent hypoxia'. The RAS imbalance caused by SARS-CoV-2 results in an accumulation of angiotensin 2 (Ang II), which activates the angiotensin 2 type 1 receptor (AT1R) and triggers a harmful cascade of intracellular signals leading to the nuclear translocation of the hypoxia-inducible factor (HIF)-1α. HIF-1α transactivates many genes including the angiotensin-converting enzyme 1 (ACE1), while at the same time, ACE2 is downregulated. A growing number of cells is maintained in a hypoxic condition that is self-sustained by the presence of the virus and the ACE1/ACE2 ratio imbalance. This is associated with a progressive worsening of the patient's biological parameters including decreased oxygen saturation, without further clinical manifestations. When too many cells activate the Ang II-AT1R-HIF-1α axis, there is a 'hypoxic spillover', which marks the tipping point between 'silent' and symptomatic hypoxia in the patient. Immediate ventilation is required to prevent the 'hypoxic spillover'.
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Affiliation(s)
- Christian Albert Devaux
- Institut de Recherche pour le Développement, Assistance Publique Hôpitaux de Marseille, Microbes Evolution Phylogeny and Infection Laboratory, Aix-Marseille University, 13000 Marseille, France
- Institut Hospitalo-Universitaire-Méditerranée Infection, 13000 Marseille, France
- Centre National de la Recherche Scientifique, 13000 Marseille, France
| | - Jean-Christophe Lagier
- Institut de Recherche pour le Développement, Assistance Publique Hôpitaux de Marseille, Microbes Evolution Phylogeny and Infection Laboratory, Aix-Marseille University, 13000 Marseille, France
- Institut Hospitalo-Universitaire-Méditerranée Infection, 13000 Marseille, France
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Endocytosis and signaling of angiotensin II type 1 receptor. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2023; 194:141-157. [PMID: 36631190 DOI: 10.1016/bs.pmbts.2022.08.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A vasoactive octapeptide angiotensin II (Ang II) hormone is the key regulator of the renin-angiotensin system (RAS). It binds with the two different plasma membrane receptors like angiotensin II type 1 (AT1) and type 2 (AT2) and consequence various biological responses occur. Further, AT1 has two subtypes such as AT1A and AT1B. These angiotensin receptors are classified to be G protein-coupled receptors (GPCRs). The main constituent of RAS is the AT1 receptor (AT1R), and its activation, signal transduction, and regulation have been extensively studied. After Ang II stimulation, the ligand-receptor complexes internalized and trafficked through the early endosome, recycling endosome, and some receptors skipped the recycling endosome and trafficked to the lysosome for metabolic degradation. Moreover, some short sequence motifs located in the carboxyl-terminus (CT) of the receptor play a vital role in the internalization, phosphorylation, subcellular trafficking, signaling, and desensitization. Furthermore, in endocytosis, the various proteins interact with the CT region of the receptor. This chapter highlights the basic mechanism of AT1 receptor internalization, trafficking and signaling in both physiological and pathophysiological conditions.
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Devaux CA, Camoin-Jau L. An update on angiotensin-converting enzyme 2 structure/functions, polymorphism, and duplicitous nature in the pathophysiology of coronavirus disease 2019: Implications for vascular and coagulation disease associated with severe acute respiratory syndrome coronavirus infection. Front Microbiol 2022; 13:1042200. [PMID: 36519165 PMCID: PMC9742611 DOI: 10.3389/fmicb.2022.1042200] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 11/07/2022] [Indexed: 08/01/2023] Open
Abstract
It has been known for many years that the angiotensin-converting enzyme 2 (ACE2) is a cell surface enzyme involved in the regulation of blood pressure. More recently, it was proven that the severe acute respiratory syndrome coronavirus (SARS-CoV-2) interacts with ACE2 to enter susceptible human cells. This functional duality of ACE2 tends to explain why this molecule plays such an important role in the clinical manifestations of coronavirus disease 2019 (COVID-19). At the very start of the pandemic, a publication from our Institute (entitled "ACE2 receptor polymorphism: susceptibility to SARS-CoV-2, hypertension, multi-organ failure, and COVID-19 disease outcome"), was one of the first reviews linking COVID-19 to the duplicitous nature of ACE2. However, even given that COVID-19 pathophysiology may be driven by an imbalance in the renin-angiotensin system (RAS), we were still far from understanding the complexity of the mechanisms which are controlled by ACE2 in different cell types. To gain insight into the physiopathology of SARS-CoV-2 infection, it is essential to consider the polymorphism and expression levels of the ACE2 gene (including its alternative isoforms). Over the past 2 years, an impressive amount of new results have come to shed light on the role of ACE2 in the pathophysiology of COVID-19, requiring us to update our analysis. Genetic linkage studies have been reported that highlight a relationship between ACE2 genetic variants and the risk of developing hypertension. Currently, many research efforts are being undertaken to understand the links between ACE2 polymorphism and the severity of COVID-19. In this review, we update the state of knowledge on the polymorphism of ACE2 and its consequences on the susceptibility of individuals to SARS-CoV-2. We also discuss the link between the increase of angiotensin II levels among SARS-CoV-2-infected patients and the development of a cytokine storm associated microvascular injury and obstructive thrombo-inflammatory syndrome, which represent the primary causes of severe forms of COVID-19 and lethality. Finally, we summarize the therapeutic strategies aimed at preventing the severe forms of COVID-19 that target ACE2. Changing paradigms may help improve patients' therapy.
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Affiliation(s)
- Christian A. Devaux
- Aix-Marseille Université, IRD, APHM, MEPHI, IHU–Méditerranée Infection, Marseille, France
- Center National de la Recherche Scientifique, Marseille, France
| | - Laurence Camoin-Jau
- Aix-Marseille Université, IRD, APHM, MEPHI, IHU–Méditerranée Infection, Marseille, France
- Laboratoire d’Hématologie, Hôpital de La Timone, APHM, Boulevard Jean-Moulin, Marseille, France
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5
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Biased activation of β 2-AR/Gi/GRK2 signal pathway attenuated β 1-AR sustained activation induced by β 1-adrenergic receptor autoantibody. Cell Death Dis 2021; 7:340. [PMID: 34750352 PMCID: PMC8576015 DOI: 10.1038/s41420-021-00735-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 09/14/2021] [Accepted: 10/19/2021] [Indexed: 01/14/2023]
Abstract
Heart failure is the terminal stage of many cardiac diseases, in which β1-adrenoceptor (β1-AR) autoantibody (β1-AA) has a causative role. By continuously activating β1-AR, β1-AA can induce cytotoxicity, leading to cardiomyocyte apoptosis and heart dysfunction. However, the mechanism underlying the persistent activation of β1-AR by β1-AA is not fully understood. Receptor endocytosis has a critical role in terminating signals over time. β2-adrenoceptor (β2-AR) is involved in the regulation of β1-AR signaling. This research aimed to clarify the mechanism of the β1-AA-induced sustained activation of β1-AR and explore the role of the β2-AR/Gi-signaling pathway in this process. The beating frequency of neonatal rat cardiomyocytes, cyclic adenosine monophosphate content, and intracellular Ca2+ levels were examined to detect the activation of β1-AA. Total internal reflection fluorescence microscopy was used to detect the endocytosis of β1-AR. ICI118551 was used to assess β2-AR/Gi function in β1-AR sustained activation induced by β1-AA in vitro and in vivo. Monoclonal β1-AA derived from a mouse hybridoma could continuously activate β1-AR. β1-AA-restricted β1-AR endocytosis, which was reversed by overexpressing the endocytosis scaffold protein β-arrestin1/2, resulting in the cessation of β1-AR signaling. β2-AR could promote β1-AR endocytosis, as demonstrated by overexpressing/interfering with β2-AR in HL-1 cells, whereas β1-AA inhibited the binding of β2-AR to β1-AR, as determined by surface plasmon resonance. ICI118551 biasedly activated the β2-AR/Gi/G protein-coupled receptor kinase 2 (GRK2) pathway, leading to the arrest of limited endocytosis and continuous activation of β1-AR by β1-AA in vitro. In vivo, ICI118551 treatment attenuated myocardial fiber rupture and left ventricular dysfunction in β1-AA-positive mice. This study showed that β1-AA continuously activated β1-AR by inhibiting receptor endocytosis. Biased activation of the β2-AR/Gi/GRK2 signaling pathway could promote β1-AR endocytosis restricted by β1-AA, terminate signal transduction, and alleviate heart damage.
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Song X, Zou X, Ge W, Hou C, Cao Z, Zhao H, Zhang T, Jin L, Fu Y, Kong W, Yan C, Cai J, Wang J. Blocking FcγRIIB in Smooth Muscle Cells Reduces Hypertension. Circ Res 2021; 129:308-325. [PMID: 33980031 DOI: 10.1161/circresaha.120.318447] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
[Figure: see text].
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MESH Headings
- Animals
- Antibodies/pharmacology
- Antihypertensive Agents/pharmacology
- Blood Pressure/drug effects
- Case-Control Studies
- Disease Models, Animal
- Extracellular Signal-Regulated MAP Kinases/metabolism
- Female
- HEK293 Cells
- Humans
- Hypertension/genetics
- Hypertension/metabolism
- Hypertension/physiopathology
- Hypertension/prevention & control
- Immunoglobulin G/blood
- Male
- Mice, Inbred C57BL
- Mice, Knockout
- Middle Aged
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/physiopathology
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/metabolism
- Rats
- Receptor, Angiotensin, Type 1/metabolism
- Receptors, IgG/antagonists & inhibitors
- Receptors, IgG/genetics
- Receptors, IgG/metabolism
- Signal Transduction
- Vascular Remodeling/drug effects
- Mice
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Affiliation(s)
- Xiaomin Song
- Department of Pathophysiology, State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences (X.S., X.Z., W.G., C.H., Z.C., H.Z., J.W.), Chinese Academy of Medical Sciences, Peking Union Medical College, China
| | - Xuan Zou
- Department of Pathophysiology, State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences (X.S., X.Z., W.G., C.H., Z.C., H.Z., J.W.), Chinese Academy of Medical Sciences, Peking Union Medical College, China
| | - Weipeng Ge
- Department of Pathophysiology, State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences (X.S., X.Z., W.G., C.H., Z.C., H.Z., J.W.), Chinese Academy of Medical Sciences, Peking Union Medical College, China
| | - Cuiliu Hou
- Department of Pathophysiology, State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences (X.S., X.Z., W.G., C.H., Z.C., H.Z., J.W.), Chinese Academy of Medical Sciences, Peking Union Medical College, China
| | - Zhujie Cao
- Department of Pathophysiology, State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences (X.S., X.Z., W.G., C.H., Z.C., H.Z., J.W.), Chinese Academy of Medical Sciences, Peking Union Medical College, China
| | - Hongmei Zhao
- Department of Pathophysiology, State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences (X.S., X.Z., W.G., C.H., Z.C., H.Z., J.W.), Chinese Academy of Medical Sciences, Peking Union Medical College, China
| | - Tiantian Zhang
- Department Physiology, State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences (T.Z.), Chinese Academy of Medical Sciences, Peking Union Medical College, China
| | - Ling Jin
- State Key Laboratory of Cardiovascular Disease, Beijing Key Laboratory for Molecular Diagnostics of Cardiovascular Diseases, Center of Laboratory Medicine, Fuwai Hospital, National Center for Cardiovascular Diseases (L.J., J.C.), Chinese Academy of Medical Sciences, Peking Union Medical College, China
| | - Yi Fu
- Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Beijing, China (Y.F., W.K.)
- Key Laboratory of Molecular Cardiovascular Science, Ministry of Education (Y.F., W.K.)
| | - Wei Kong
- Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Beijing, China (Y.F., W.K.)
- Key Laboratory of Molecular Cardiovascular Science, Ministry of Education (Y.F., W.K.)
| | - Chen Yan
- Aab Cardiovascular Research Institute, Medicine, University of Rochester School of Medicine and Dentistry, NY (C.Y.)
| | - Jun Cai
- State Key Laboratory of Cardiovascular Disease, Beijing Key Laboratory for Molecular Diagnostics of Cardiovascular Diseases, Center of Laboratory Medicine, Fuwai Hospital, National Center for Cardiovascular Diseases (L.J., J.C.), Chinese Academy of Medical Sciences, Peking Union Medical College, China
| | - Jing Wang
- Department of Pathophysiology, State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences (X.S., X.Z., W.G., C.H., Z.C., H.Z., J.W.), Chinese Academy of Medical Sciences, Peking Union Medical College, China
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7
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Moo EV, van Senten JR, Bräuner-Osborne H, Møller TC. Arrestin-Dependent and -Independent Internalization of G Protein-Coupled Receptors: Methods, Mechanisms, and Implications on Cell Signaling. Mol Pharmacol 2021; 99:242-255. [PMID: 33472843 DOI: 10.1124/molpharm.120.000192] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 01/07/2021] [Indexed: 01/05/2023] Open
Abstract
Agonist-induced endocytosis is a key regulatory mechanism for controlling the responsiveness of the cell by changing the density of cell surface receptors. In addition to the role of endocytosis in signal termination, endocytosed G protein-coupled receptors (GPCRs) have been found to signal from intracellular compartments of the cell. Arrestins are generally believed to be the master regulators of GPCR endocytosis by binding to both phosphorylated receptors and adaptor protein 2 (AP-2) or clathrin, thus recruiting receptors to clathrin-coated pits to facilitate the internalization process. However, many other functions have been described for arrestins that do not relate to their role in terminating signaling. Additionally, there are now more than 30 examples of GPCRs that internalize independently of arrestins. Here we review the methods, pharmacological tools, and cellular backgrounds used to determine the role of arrestins in receptor internalization, highlighting their advantages and caveats. We also summarize key examples of arrestin-independent GPCR endocytosis in the literature and their suggested alternative endocytosis pathway (e.g., the caveolae-dependent and fast endophilin-mediated endocytosis pathways). Finally, we consider the possible function of arrestins recruited to GPCRs that are endocytosed independently of arrestins, including the catalytic arrestin activation paradigm. Technological improvements in recent years have advanced the field further, and, combined with the important implications of endocytosis on drug responses, this makes endocytosis an obvious parameter to include in molecular pharmacological characterization of ligand-GPCR interactions. SIGNIFICANCE STATEMENT: G protein-coupled receptor (GPCR) endocytosis is an important means to terminate receptor signaling, and arrestins play a central role in the widely accepted classical paradigm of GPCR endocytosis. In contrast to the canonical arrestin-mediated internalization, an increasing number of GPCRs are found to be endocytosed via alternate pathways, and the process appears more diverse than the previously defined "one pathway fits all."
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Affiliation(s)
- Ee Von Moo
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Jeffrey R van Senten
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Hans Bräuner-Osborne
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Thor C Møller
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
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8
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Zanaty M, Seara FAC, Nakagawa P, Deng G, Mathieu NM, Balapattabi K, Karnik SS, Grobe JL, Sigmund CD. β-Arrestin-Biased Agonist Targeting the Brain AT 1R (Angiotensin II Type 1 Receptor) Increases Aversion to Saline and Lowers Blood Pressure in Deoxycorticosterone Acetate-Salt Hypertension. Hypertension 2020; 77:420-431. [PMID: 33249862 DOI: 10.1161/hypertensionaha.120.15793] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Activation of central AT1Rs (angiotensin type 1 receptors) is required for the increased blood pressure, polydipsia, and salt intake in deoxycorticosterone acetate (DOCA)-salt hypertension. TRV120027 (TRV027) is an AT1R-biased agonist that selectively acts through β-arrestin. We hypothesized that intracerebroventricular administration of TRV027 would ameliorate the effects of DOCA-salt. In a neuronal cell line, TRV027 induced AT1aR internalization through dynamin and clathrin-mediated endocytosis. We next evaluated the effect of chronic intracerebroventricular infusion of TRV027 on fluid intake. We measured the relative intake of water versus various saline solutions using a 2-bottle choice paradigm in mice subjected to DOCA with a concomitant intracerebroventricular infusion of either vehicle, TRV027, or losartan. Sham mice received intracerebroventricular vehicle without DOCA. TRV027 potentiated DOCA-induced water intake in the presence or absence of saline. TRV027 and losartan both increased the aversion for saline-an effect particularly pronounced for highly aversive saline solutions. Intracerebroventricular Ang (angiotensin) II, but not TRV027, increased water and saline intake in the absence of DOCA. In a separate cohort, blood pressure responses to acute intracerebroventricular injection of vehicle, TRV, or losartan were measured by radiotelemetry in mice with established DOCA-salt hypertension. Central administration of intracerebroventricular TRV027 or losartan each caused a significant and similar reduction of blood pressure and heart rate. We conclude that administration of TRV027 a selective β-arrestin biased agonist directly into the brain increases aversion to saline and lowers blood pressure in a model of salt-sensitive hypertension. These data suggest that selective activation of AT1R β-arrestin pathways may be exploitable therapeutically.
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Affiliation(s)
- Mario Zanaty
- From the Department of Physiology, Cardiovascular Center Medical College of Wisconsin, Milwaukee, WI (M.Z., P.N., N.M.M., K.B., J.L.G., C.D.S.).,Department of Neurosurgery (M.Z.), Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA
| | - Fernando A C Seara
- Department of Pharmacology and Neuroscience (F.A.C.S., G.D.), Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA
| | - Pablo Nakagawa
- From the Department of Physiology, Cardiovascular Center Medical College of Wisconsin, Milwaukee, WI (M.Z., P.N., N.M.M., K.B., J.L.G., C.D.S.)
| | - Guorui Deng
- Department of Pharmacology and Neuroscience (F.A.C.S., G.D.), Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA
| | - Natalia M Mathieu
- From the Department of Physiology, Cardiovascular Center Medical College of Wisconsin, Milwaukee, WI (M.Z., P.N., N.M.M., K.B., J.L.G., C.D.S.)
| | - Kirthikaa Balapattabi
- From the Department of Physiology, Cardiovascular Center Medical College of Wisconsin, Milwaukee, WI (M.Z., P.N., N.M.M., K.B., J.L.G., C.D.S.)
| | - Sadashiva S Karnik
- Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH (S.S.K.)
| | - Justin L Grobe
- From the Department of Physiology, Cardiovascular Center Medical College of Wisconsin, Milwaukee, WI (M.Z., P.N., N.M.M., K.B., J.L.G., C.D.S.)
| | - Curt D Sigmund
- From the Department of Physiology, Cardiovascular Center Medical College of Wisconsin, Milwaukee, WI (M.Z., P.N., N.M.M., K.B., J.L.G., C.D.S.)
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9
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Rukavina Mikusic NL, Silva MG, Pineda AM, Gironacci MM. Angiotensin Receptors Heterodimerization and Trafficking: How Much Do They Influence Their Biological Function? Front Pharmacol 2020; 11:1179. [PMID: 32848782 PMCID: PMC7417933 DOI: 10.3389/fphar.2020.01179] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Accepted: 07/20/2020] [Indexed: 01/03/2023] Open
Abstract
G-protein–coupled receptors (GPCRs) are targets for around one third of currently approved and clinical prescribed drugs and represent the largest and most structurally diverse family of transmembrane signaling proteins, with almost 1000 members identified in the human genome. Upon agonist stimulation, GPCRs are internalized and trafficked inside the cell: they may be targeted to different organelles, recycled back to the plasma membrane or be degraded. Once inside the cell, the receptors may initiate other signaling pathways leading to different biological responses. GPCRs’ biological function may also be influenced by interaction with other receptors. Thus, the ultimate cellular response may depend not only on the activation of the receptor from the cell membrane, but also from receptor trafficking and/or the interaction with other receptors. This review is focused on angiotensin receptors and how their biological function is influenced by trafficking and interaction with others receptors.
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Affiliation(s)
- Natalia L Rukavina Mikusic
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Dpto. Química Biológica, IQUIFIB (UBA-CONICET), Buenos Aires, Argentina
| | - Mauro G Silva
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Dpto. Química Biológica, IQUIFIB (UBA-CONICET), Buenos Aires, Argentina
| | - Angélica M Pineda
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Dpto. Química Biológica, IQUIFIB (UBA-CONICET), Buenos Aires, Argentina
| | - Mariela M Gironacci
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Dpto. Química Biológica, IQUIFIB (UBA-CONICET), Buenos Aires, Argentina
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10
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Bouressam ML, Lecat S, Raoul A, Gaucher C, Perrin-Sarrado C, Lartaud I, Dupuis F. S-nitrosoglutathione inhibits cerebrovascular angiotensin II-dependent and -independent AT 1 receptor responses: A possible role of S-nitrosation. Br J Pharmacol 2019; 176:2049-2062. [PMID: 30822355 DOI: 10.1111/bph.14644] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 01/21/2019] [Accepted: 02/13/2019] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE Angiotensin II (AngII) and NO regulate the cerebral circulation. AngII AT1 receptors exert ligand-dependent and ligand-independent (myogenic tone [MT]) vasoconstriction of cerebral vessels. NO induces post-translational modifications of proteins such as S-nitrosation (redox modification of cysteine residues). In cultured cells, S-nitrosation decreases AngII's affinity for the AT1 receptor. The present work evaluated the functional consequences of S-nitrosation on both AngII-dependent and AngII-independent cerebrovascular responses. EXPERIMENTAL APPROACH S-Nitrosation was induced in rat isolated middle cerebral arteries by pretreatment with the NO donors, S-nitrosoglutathione (GSNO) or sodium nitroprusside (SNP). Agonist-dependent activation of AT1 receptors was evaluated by obtaining concentration-response curves to AngII. Ligand-independent activation of AT1 receptors was evaluated by calculating MT (active vs. passive diameter) at pressures ranging from 20 to 200 mmHg in the presence or not of a selective AT1 receptor inverse agonist. KEY RESULTS GSNO or SNP completely abolished the AngII-dependent AT1 receptor-mediated vasoconstriction of cerebral arteries. GSNO had no impact on responses to other vasoconstrictors sharing (phenylephrine, U46619) or not (5-HT) the same signalling pathway. MT was reduced by GSNO, and the addition of losartan did not further decrease MT, suggesting that GSNO blocks AT1 receptor-dependent MT. Ascorbate (which reduces S-nitrosated compounds) restored the response to AngII but not the soluble GC inhibitor ODQ, suggesting that these effects are mediated by S-nitrosation rather than by S-nitrosylation. CONCLUSIONS AND IMPLICATIONS In rat middle cerebral arteries, GSNO pretreatment specifically affects the AT1 receptor and reduces both AngII-dependent and AngII-independent activation, most likely through AT1 receptor S-nitrosation.
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Affiliation(s)
| | - Sandra Lecat
- BSC UMR7242 "GPCRs, pain and inflammation" team, CNRS, Université de Strasbourg Labex Medalis, Illkirch, France
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11
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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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12
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Forrester SJ, Booz GW, Sigmund CD, Coffman TM, Kawai T, Rizzo V, Scalia R, Eguchi S. Angiotensin II Signal Transduction: An Update on Mechanisms of Physiology and Pathophysiology. Physiol Rev 2018; 98:1627-1738. [PMID: 29873596 DOI: 10.1152/physrev.00038.2017] [Citation(s) in RCA: 585] [Impact Index Per Article: 97.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The renin-angiotensin-aldosterone system plays crucial roles in cardiovascular physiology and pathophysiology. However, many of the signaling mechanisms have been unclear. The angiotensin II (ANG II) type 1 receptor (AT1R) is believed to mediate most functions of ANG II in the system. AT1R utilizes various signal transduction cascades causing hypertension, cardiovascular remodeling, and end organ damage. Moreover, functional cross-talk between AT1R signaling pathways and other signaling pathways have been recognized. Accumulating evidence reveals the complexity of ANG II signal transduction in pathophysiology of the vasculature, heart, kidney, and brain, as well as several pathophysiological features, including inflammation, metabolic dysfunction, and aging. In this review, we provide a comprehensive update of the ANG II receptor signaling events and their functional significances for potential translation into therapeutic strategies. AT1R remains central to the system in mediating physiological and pathophysiological functions of ANG II, and participation of specific signaling pathways becomes much clearer. There are still certain limitations and many controversies, and several noteworthy new concepts require further support. However, it is expected that rigorous translational research of the ANG II signaling pathways including those in large animals and humans will contribute to establishing effective new therapies against various diseases.
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Affiliation(s)
- Steven J Forrester
- Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University , Philadelphia, Pennsylvania ; Department of Pharmacology and Toxicology, School of Medicine, University of Mississippi Medical Center , Jackson, Mississippi ; Department of Pharmacology, Center for Hypertension Research, Roy J. and Lucille A. Carver College of Medicine, University of Iowa , Iowa City, Iowa ; and Duke-NUS, Singapore and Department of Medicine, Duke University Medical Center , Durham, North Carolina
| | - George W Booz
- Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University , Philadelphia, Pennsylvania ; Department of Pharmacology and Toxicology, School of Medicine, University of Mississippi Medical Center , Jackson, Mississippi ; Department of Pharmacology, Center for Hypertension Research, Roy J. and Lucille A. Carver College of Medicine, University of Iowa , Iowa City, Iowa ; and Duke-NUS, Singapore and Department of Medicine, Duke University Medical Center , Durham, North Carolina
| | - Curt D Sigmund
- Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University , Philadelphia, Pennsylvania ; Department of Pharmacology and Toxicology, School of Medicine, University of Mississippi Medical Center , Jackson, Mississippi ; Department of Pharmacology, Center for Hypertension Research, Roy J. and Lucille A. Carver College of Medicine, University of Iowa , Iowa City, Iowa ; and Duke-NUS, Singapore and Department of Medicine, Duke University Medical Center , Durham, North Carolina
| | - Thomas M Coffman
- Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University , Philadelphia, Pennsylvania ; Department of Pharmacology and Toxicology, School of Medicine, University of Mississippi Medical Center , Jackson, Mississippi ; Department of Pharmacology, Center for Hypertension Research, Roy J. and Lucille A. Carver College of Medicine, University of Iowa , Iowa City, Iowa ; and Duke-NUS, Singapore and Department of Medicine, Duke University Medical Center , Durham, North Carolina
| | - Tatsuo Kawai
- Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University , Philadelphia, Pennsylvania ; Department of Pharmacology and Toxicology, School of Medicine, University of Mississippi Medical Center , Jackson, Mississippi ; Department of Pharmacology, Center for Hypertension Research, Roy J. and Lucille A. Carver College of Medicine, University of Iowa , Iowa City, Iowa ; and Duke-NUS, Singapore and Department of Medicine, Duke University Medical Center , Durham, North Carolina
| | - Victor Rizzo
- Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University , Philadelphia, Pennsylvania ; Department of Pharmacology and Toxicology, School of Medicine, University of Mississippi Medical Center , Jackson, Mississippi ; Department of Pharmacology, Center for Hypertension Research, Roy J. and Lucille A. Carver College of Medicine, University of Iowa , Iowa City, Iowa ; and Duke-NUS, Singapore and Department of Medicine, Duke University Medical Center , Durham, North Carolina
| | - Rosario Scalia
- Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University , Philadelphia, Pennsylvania ; Department of Pharmacology and Toxicology, School of Medicine, University of Mississippi Medical Center , Jackson, Mississippi ; Department of Pharmacology, Center for Hypertension Research, Roy J. and Lucille A. Carver College of Medicine, University of Iowa , Iowa City, Iowa ; and Duke-NUS, Singapore and Department of Medicine, Duke University Medical Center , Durham, North Carolina
| | - Satoru Eguchi
- Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University , Philadelphia, Pennsylvania ; Department of Pharmacology and Toxicology, School of Medicine, University of Mississippi Medical Center , Jackson, Mississippi ; Department of Pharmacology, Center for Hypertension Research, Roy J. and Lucille A. Carver College of Medicine, University of Iowa , Iowa City, Iowa ; and Duke-NUS, Singapore and Department of Medicine, Duke University Medical Center , Durham, North Carolina
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13
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Bhattarai N, Mathis JM, Chen M, Pérez RL, Siraj N, Magut PKS, McDonough K, Sahasrabudhe G, Warner IM. Endocytic Selective Toxicity of Rhodamine 6G nanoGUMBOS in Breast Cancer Cells. Mol Pharm 2018; 15:3837-3845. [PMID: 29975540 DOI: 10.1021/acs.molpharmaceut.8b00339] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Herein, we report on the role of endocytosis in the selective chemotherpeutic toxicity of rhodamine 6G (R6G) based nanomaterials, i.e., nanoGUMBOS, that are derived from a group of uniform materials based on organic salts (GUMBOS). Evaluation of cellular uptake in the presence and absence of endocytosis inhibitors suggests nanoGUMBOS internalization via clathrin-mediated endocytosis in cancer cells and reveals lack of endocytic internalization in normal cells. Results from characterization of these nanomaterials suggest that endocytic internalization in cancer cells leads to nanoGUMBOS dissociation within the endosomal environment. This ultimately results in selective cytotoxicity of the nanoGUMBOS for cancer cells with no toxicity toward normal cells under examined conditions. Following examination of the selectivity mechanism, in vivo investigations were performed to examine potential therapeutic properties of these nanoparticles. Remarkably, nanoGUMBOS treatment using a mouse xenograft model reduced the tumor volume by 50% suggesting retention of in vitro therapeutic properties in vivo. These results corroborate the selective behavior of nanoGUMBOS and demonstrate their in vivo therapeutic effects, providing further insight into the possible use of these nanomaterials as potential chemotherapeutic agents.
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Affiliation(s)
- Nimisha Bhattarai
- Department of Chemistry , Louisiana State University , Baton Rouge , Louisiana 70803 , United States
| | - J Michael Mathis
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine , Louisiana State University , Baton Rouge , Louisiana 70803 , United States
| | - Mi Chen
- Department of Chemistry , Louisiana State University , Baton Rouge , Louisiana 70803 , United States
| | - Rocío L Pérez
- Department of Chemistry , Louisiana State University , Baton Rouge , Louisiana 70803 , United States
| | - Noureen Siraj
- Department of Chemistry , Louisiana State University , Baton Rouge , Louisiana 70803 , United States
| | - Paul K S Magut
- Department of Chemistry , Louisiana State University , Baton Rouge , Louisiana 70803 , United States
| | - Karen McDonough
- AgCenter Biotechnology Laboratories , Louisiana State University , Baton Rouge , Louisiana 70803 , United States
| | - Girija Sahasrabudhe
- Department of Chemistry , Louisiana State University , Baton Rouge , Louisiana 70803 , United States
| | - Isiah M Warner
- Department of Chemistry , Louisiana State University , Baton Rouge , Louisiana 70803 , United States
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14
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Tóth AD, Prokop S, Gyombolai P, Várnai P, Balla A, Gurevich VV, Hunyady L, Turu G. Heterologous phosphorylation-induced formation of a stability lock permits regulation of inactive receptors by β-arrestins. J Biol Chem 2017; 293:876-892. [PMID: 29146594 DOI: 10.1074/jbc.m117.813139] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 11/08/2017] [Indexed: 12/24/2022] Open
Abstract
β-Arrestins are key regulators and signal transducers of G protein-coupled receptors (GPCRs). The interaction between receptors and β-arrestins is generally believed to require both receptor activity and phosphorylation by GPCR kinases. In this study, we investigated whether β-arrestins are able to bind second messenger kinase-phosphorylated, but inactive receptors as well. Because heterologous phosphorylation is a common phenomenon among GPCRs, this mode of β-arrestin activation may represent a novel mechanism of signal transduction and receptor cross-talk. Here we demonstrate that activation of protein kinase C (PKC) by phorbol myristate acetate, Gq/11-coupled GPCR, or epidermal growth factor receptor stimulation promotes β-arrestin2 recruitment to unliganded AT1 angiotensin receptor (AT1R). We found that this interaction depends on the stability lock, a structure responsible for the sustained binding between GPCRs and β-arrestins, formed by phosphorylated serine-threonine clusters in the receptor's C terminus and two conserved phosphate-binding lysines in the β-arrestin2 N-domain. Using improved FlAsH-based serine-threonine clusters β-arrestin2 conformational biosensors, we also show that the stability lock not only stabilizes the receptor-β-arrestin interaction, but also governs the structural rearrangements within β-arrestins. Furthermore, we found that β-arrestin2 binds to PKC-phosphorylated AT1R in a distinct active conformation, which triggers MAPK recruitment and receptor internalization. Our results provide new insights into the activation of β-arrestins and reveal their novel role in receptor cross-talk.
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Affiliation(s)
- András D Tóth
- From the Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest H-1094, Hungary
| | - Susanne Prokop
- From the Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest H-1094, Hungary
| | - Pál Gyombolai
- From the Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest H-1094, Hungary.,the MTA-SE Laboratory of Molecular Physiology, Hungarian Academy of Sciences and Semmelweis University, Budapest H-1094, Hungary, and
| | - Péter Várnai
- From the Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest H-1094, Hungary.,the MTA-SE Laboratory of Molecular Physiology, Hungarian Academy of Sciences and Semmelweis University, Budapest H-1094, Hungary, and
| | - András Balla
- From the Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest H-1094, Hungary.,the MTA-SE Laboratory of Molecular Physiology, Hungarian Academy of Sciences and Semmelweis University, Budapest H-1094, Hungary, and
| | - Vsevolod V Gurevich
- the Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232
| | - László Hunyady
- From the Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest H-1094, Hungary, .,the MTA-SE Laboratory of Molecular Physiology, Hungarian Academy of Sciences and Semmelweis University, Budapest H-1094, Hungary, and
| | - Gábor Turu
- From the Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest H-1094, Hungary.,the MTA-SE Laboratory of Molecular Physiology, Hungarian Academy of Sciences and Semmelweis University, Budapest H-1094, Hungary, and
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15
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Cerniello FM, Carretero OA, Longo Carbajosa NA, Cerrato BD, Santos RA, Grecco HE, Gironacci MM. MAS1 Receptor Trafficking Involves ERK1/2 Activation Through a β-Arrestin2-Dependent Pathway. Hypertension 2017; 70:982-989. [PMID: 28874464 DOI: 10.1161/hypertensionaha.117.09789] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 06/21/2017] [Accepted: 08/11/2017] [Indexed: 12/15/2022]
Abstract
The MAS1 receptor (R) exerts protective effects in the brain, heart, vessels, and kidney. R trafficking plays a critical function in signal termination and propagation and in R resensitization. We examined MAS1R internalization and trafficking on agonist stimulation and the role of β-arrestin2 in the activation of ERK1/2 (extracellular signal-regulated kinase 1/2) and Akt after MAS1R stimulation. Human embryonic kidney 293T cells were transfected with the coding sequence for MAS1R-YFP (MAS1R fused to yellow fluorescent protein). MAS1R internalization was evaluated by measuring the MAS1R present in the plasma membrane after agonist stimulation using a ligand-binding assay. MAS1R trafficking was evaluated by its colocalization with trafficking markers. MAS1R internalization was blocked in the presence of shRNAcaveolin-1 and with dominant negatives for Eps15 (a protein involved in endocytosed Rs by clathrin-coated pits) and for dynamin. After stimulation, MAS1R colocalized with Rab11-a slow recycling vesicle marker-and not with Rab4-a fast recycling vesicle marker-or LysoTracker-a lysosome marker. Cells transfected with MAS1R showed an increase in Akt and ERK1/2 activation on angiotensin-(1-7) stimulation, which was blocked when the clathrin-coated pits pathway was blocked. Suppression of β-arrestin2 by shRNA reduced the angiotensin-(1-7)-induced ERK1/2 activation, whereas Akt activation was not modified. We conclude that on agonist stimulation, MAS1R is internalized through clathrin-coated pits and caveolae in a dynamin-dependent manner and is then slowly recycled back to the plasma membrane. MAS1R induced Akt and ERK1/2 activation from early endosomes, and the activation of ERK1/2 was mediated by β-arrestin2. Thus, MAS1R activity and density may be tightly controlled by the cell.
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Affiliation(s)
- Flavia M Cerniello
- From the Departamento de Química Biológica, IQUIFIB-CONICET, Universidad de Buenos Aires, Argentina (F.M.C., N.L.C., B.D.C., M.M.G.); Division of Hypertension and Vascular Research, Henry Ford Hospital, Detroit, MI (O.A.C.); Department of Physiology, Federal University of Minas Gerais, Belo Horizonte, Brazil (R.A.S.); and Departamento de Física, Universidad de Buenos Aires and IFIBA-CONICET, Buenos Aires, Argentina (H.E.G.)
| | - Oscar A Carretero
- From the Departamento de Química Biológica, IQUIFIB-CONICET, Universidad de Buenos Aires, Argentina (F.M.C., N.L.C., B.D.C., M.M.G.); Division of Hypertension and Vascular Research, Henry Ford Hospital, Detroit, MI (O.A.C.); Department of Physiology, Federal University of Minas Gerais, Belo Horizonte, Brazil (R.A.S.); and Departamento de Física, Universidad de Buenos Aires and IFIBA-CONICET, Buenos Aires, Argentina (H.E.G.)
| | - Nadia A Longo Carbajosa
- From the Departamento de Química Biológica, IQUIFIB-CONICET, Universidad de Buenos Aires, Argentina (F.M.C., N.L.C., B.D.C., M.M.G.); Division of Hypertension and Vascular Research, Henry Ford Hospital, Detroit, MI (O.A.C.); Department of Physiology, Federal University of Minas Gerais, Belo Horizonte, Brazil (R.A.S.); and Departamento de Física, Universidad de Buenos Aires and IFIBA-CONICET, Buenos Aires, Argentina (H.E.G.)
| | - Bruno D Cerrato
- From the Departamento de Química Biológica, IQUIFIB-CONICET, Universidad de Buenos Aires, Argentina (F.M.C., N.L.C., B.D.C., M.M.G.); Division of Hypertension and Vascular Research, Henry Ford Hospital, Detroit, MI (O.A.C.); Department of Physiology, Federal University of Minas Gerais, Belo Horizonte, Brazil (R.A.S.); and Departamento de Física, Universidad de Buenos Aires and IFIBA-CONICET, Buenos Aires, Argentina (H.E.G.)
| | - Robson A Santos
- From the Departamento de Química Biológica, IQUIFIB-CONICET, Universidad de Buenos Aires, Argentina (F.M.C., N.L.C., B.D.C., M.M.G.); Division of Hypertension and Vascular Research, Henry Ford Hospital, Detroit, MI (O.A.C.); Department of Physiology, Federal University of Minas Gerais, Belo Horizonte, Brazil (R.A.S.); and Departamento de Física, Universidad de Buenos Aires and IFIBA-CONICET, Buenos Aires, Argentina (H.E.G.)
| | - Hernán E Grecco
- From the Departamento de Química Biológica, IQUIFIB-CONICET, Universidad de Buenos Aires, Argentina (F.M.C., N.L.C., B.D.C., M.M.G.); Division of Hypertension and Vascular Research, Henry Ford Hospital, Detroit, MI (O.A.C.); Department of Physiology, Federal University of Minas Gerais, Belo Horizonte, Brazil (R.A.S.); and Departamento de Física, Universidad de Buenos Aires and IFIBA-CONICET, Buenos Aires, Argentina (H.E.G.)
| | - Mariela M Gironacci
- From the Departamento de Química Biológica, IQUIFIB-CONICET, Universidad de Buenos Aires, Argentina (F.M.C., N.L.C., B.D.C., M.M.G.); Division of Hypertension and Vascular Research, Henry Ford Hospital, Detroit, MI (O.A.C.); Department of Physiology, Federal University of Minas Gerais, Belo Horizonte, Brazil (R.A.S.); and Departamento de Física, Universidad de Buenos Aires and IFIBA-CONICET, Buenos Aires, Argentina (H.E.G.).
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16
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Hunyady L, Gáborik Z, Vauquelin G, Catt KJ. Review: Structural requirements for signalling and regulation of AT1-receptors. J Renin Angiotensin Aldosterone Syst 2016; 2:S16-S23. [DOI: 10.1177/14703203010020010301] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Affiliation(s)
- László Hunyady
- Department of Physiology, Semmelweis University Medical
School, Budapest, Hungary,
| | - Zsuzsanna Gáborik
- Department of Physiology, Semmelweis University Medical
School, Budapest, Hungary
| | - Georges Vauquelin
- Department of Molecular and Biochemical Pharmacology,
Institute of Molecular Biology and Biotechnology, Free University of Brussels
(VUB), Sint-Genesius Rode, Belgium
| | - Kevin J Catt
- Endocrinology and Reproduction Research Branch, National
Institute of Child Health and Human Development, National Institutes of Health,
Bethesda, USA
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17
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Morinelli TA, Luttrell LM, Strungs EG, Ullian ME. Angiotensin II receptors and peritoneal dialysis-induced peritoneal fibrosis. Int J Biochem Cell Biol 2016; 77:240-50. [PMID: 27167177 PMCID: PMC5038354 DOI: 10.1016/j.biocel.2016.04.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 04/25/2016] [Accepted: 04/26/2016] [Indexed: 12/22/2022]
Abstract
The vasoactive hormone angiotensin II initiates its major hemodynamic effects through interaction with AT1 receptors, a member of the class of G protein-coupled receptors. Acting through its AT1R, angiotensin II regulates blood pressure and renal salt and water balance. Recent evidence points to additional pathological influences of activation of AT1R, in particular inflammation, fibrosis and atherosclerosis. The transcription factor nuclear factor κB, a key mediator in inflammation and atherosclerosis, can be activated by angiotensin II through a mechanism that may involve arrestin-dependent AT1 receptor internalization. Peritoneal dialysis is a therapeutic modality for treating patients with end-stage kidney disease. The effectiveness of peritoneal dialysis at removing waste from the circulation is compromised over time as a consequence of peritoneal dialysis-induced peritoneal fibrosis. The non-physiological dialysis solution used in peritoneal dialysis, i.e. highly concentrated, hyperosmotic glucose, acidic pH as well as large volumes infused into the peritoneal cavity, contributes to the development of fibrosis. Numerous trials have been conducted altering certain components of the peritoneal dialysis fluid in hopes of preventing or delaying the fibrotic response with limited success. We hypothesize that structural activation of AT1R by hyperosmotic peritoneal dialysis fluid activates the internalization process and subsequent signaling through the transcription factor nuclear factor κB, resulting in the generation of pro-fibrotic/pro-inflammatory mediators producing peritoneal fibrosis.
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Affiliation(s)
- Thomas A Morinelli
- Division of Nephrology, Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, United States.
| | - Louis M Luttrell
- Division of Endocrinology, Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, United States; Research Service of the Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC 29401, United States
| | - Erik G Strungs
- Division of Endocrinology, Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, United States
| | - Michael E Ullian
- Division of Nephrology, Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, United States; Research Service of the Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC 29401, United States
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18
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Namkung Y, Le Gouill C, Lukashova V, Kobayashi H, Hogue M, Khoury E, Song M, Bouvier M, Laporte SA. Monitoring G protein-coupled receptor and β-arrestin trafficking in live cells using enhanced bystander BRET. Nat Commun 2016; 7:12178. [PMID: 27397672 PMCID: PMC4942582 DOI: 10.1038/ncomms12178] [Citation(s) in RCA: 188] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 06/08/2016] [Indexed: 12/14/2022] Open
Abstract
Endocytosis and intracellular trafficking of receptors are pivotal to maintain physiological functions and drug action; however, robust quantitative approaches are lacking to study such processes in live cells. Here we present new bioluminescence resonance energy transfer (BRET) sensors to quantitatively monitor G protein-coupled receptors (GPCRs) and β-arrestin trafficking. These sensors are based on bystander BRET and use the naturally interacting chromophores luciferase (RLuc) and green fluorescent protein (rGFP) from Renilla. The versatility and robustness of this approach are exemplified by anchoring rGFP at the plasma membrane or in endosomes to generate high dynamic spectrometric BRET signals on ligand-promoted recruitment or sequestration of RLuc-tagged proteins to, or from, specific cell compartments, as well as sensitive subcellular BRET imaging for protein translocation visualization. These sensors are scalable to high-throughput formats and allow quantitative pharmacological studies of GPCR trafficking in real time, in live cells, revealing ligand-dependent biased trafficking of receptor/β-arrestin complexes. Cellular signaling processes often involve trafficking of receptors and other proteins between subcellular compartments. Here the authors demonstrate a method based on the concept of Enhanced bystander Bioluminescence Resonance Energy Transfer (EbBRET) that allows efficient real time monitoring of endocytosis and trafficking.
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Affiliation(s)
- Yoon Namkung
- Department of Medicine, Research Institute of the McGill University Health Center (RI-MUHC), McGill University, Montréal, Québec, Canada H4A 3J1
| | - Christian Le Gouill
- Department of Biochemistry and Institute for Research in Immunology and Cancer (IRIC), Université de Montréal, Montréal, Québec, Canada H3C 1J4
| | - Viktoria Lukashova
- Department of Biochemistry and Institute for Research in Immunology and Cancer (IRIC), Université de Montréal, Montréal, Québec, Canada H3C 1J4
| | - Hiroyuki Kobayashi
- Department of Biochemistry and Institute for Research in Immunology and Cancer (IRIC), Université de Montréal, Montréal, Québec, Canada H3C 1J4
| | - Mireille Hogue
- Department of Biochemistry and Institute for Research in Immunology and Cancer (IRIC), Université de Montréal, Montréal, Québec, Canada H3C 1J4
| | - Etienne Khoury
- Department of Medicine, Research Institute of the McGill University Health Center (RI-MUHC), McGill University, Montréal, Québec, Canada H4A 3J1
| | - Mideum Song
- Department of Medicine, Research Institute of the McGill University Health Center (RI-MUHC), McGill University, Montréal, Québec, Canada H4A 3J1
| | - Michel Bouvier
- Department of Biochemistry and Institute for Research in Immunology and Cancer (IRIC), Université de Montréal, Montréal, Québec, Canada H3C 1J4
| | - Stéphane A Laporte
- Department of Medicine, Research Institute of the McGill University Health Center (RI-MUHC), McGill University, Montréal, Québec, Canada H4A 3J1.,Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada H3G 1Y6.,Department of Anatomy and Cell Biology, McGill University, Montréal, Québec, Canada H3A 0C7
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19
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Castrop H. A role for AT1 receptor-associated proteins in blood pressure regulation. Curr Opin Pharmacol 2015; 21:43-7. [DOI: 10.1016/j.coph.2014.12.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Revised: 12/18/2014] [Accepted: 12/19/2014] [Indexed: 01/11/2023]
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20
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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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Kockx M, Karunakaran D, Traini M, Xue J, Huang KY, Nawara D, Gaus K, Jessup W, Robinson PJ, Kritharides L. Pharmacological inhibition of dynamin II reduces constitutive protein secretion from primary human macrophages. PLoS One 2014; 9:e111186. [PMID: 25347775 PMCID: PMC4210248 DOI: 10.1371/journal.pone.0111186] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 09/22/2014] [Indexed: 12/14/2022] Open
Abstract
Dynamins are fission proteins that mediate endocytic and exocytic membrane events and are pharmacological therapeutic targets. These studies investigate whether dynamin II regulates constitutive protein secretion and show for the first time that pharmacological inhibition of dynamin decreases secretion of apolipoprotein E (apoE) and several other proteins constitutively secreted from primary human macrophages. Inhibitors that target recruitment of dynamin to membranes (MiTMABs) or directly target the GTPase domain (Dyngo or Dynole series), dose- and time- dependently reduced the secretion of apoE. SiRNA oligo’s targeting all isoforms of dynamin II confirmed the involvement of dynamin II in apoE secretion. Inhibition of secretion was not mediated via effects on mRNA or protein synthesis. 2D-gel electrophoresis showed that inhibition occurred after apoE was processed and glycosylated in the Golgi and live cell imaging showed that inhibited secretion was associated with reduced post-Golgi movement of apoE-GFP-containing vesicles. The effect was not restricted to macrophages, and was not mediated by the effects of the inhibitors on microtubules. Inhibition of dynamin also altered the constitutive secretion of other proteins, decreasing the secretion of fibronectin, matrix metalloproteinase 9, Chitinase-3-like protein 1 and lysozyme but unexpectedly increasing the secretion of the inflammatory mediator cyclophilin A. We conclude that pharmacological inhibitors of dynamin II modulate the constitutive secretion of macrophage apoE as a class effect, and that their capacity to modulate protein secretion may affect a range of biological processes.
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Affiliation(s)
- Maaike Kockx
- Atherosclerosis Laboratory, ANZAC Research Institute, University of Sydney, Sydney, Australia
| | - Denuja Karunakaran
- Centre for Vascular Research, University of New South Wales, Sydney, Australia
- University of Ottawa Heart Institute, Ottawa, Canada
| | - Mathew Traini
- Atherosclerosis Laboratory, ANZAC Research Institute, University of Sydney, Sydney, Australia
| | - Jing Xue
- Children’s Medical Research Institute, University of Sydney, Sydney, Australia
| | - Kuan Yen Huang
- Centre for Vascular Research, University of New South Wales, Sydney, Australia
| | - Diana Nawara
- Atherosclerosis Laboratory, ANZAC Research Institute, University of Sydney, Sydney, Australia
| | - Katharina Gaus
- Centre for Vascular Research, University of New South Wales, Sydney, Australia
| | - Wendy Jessup
- Atherosclerosis Laboratory, ANZAC Research Institute, University of Sydney, Sydney, Australia
| | - Phillip J. Robinson
- Children’s Medical Research Institute, University of Sydney, Sydney, Australia
| | - Leonard Kritharides
- Department of Cardiology and ANZAC Research Institute, Concord Hospital, University of Sydney, Sydney, Australia
- * E-mail:
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22
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PAN ZHIGUO, SHAO YU, DONG WENPENG, LIU CHENXI, CHEN YI, JIN HUI, TANG LIQUN, QIU JUNMING, SU LEI. Xuebijing attenuates hypotension through the upregulation of angiotensin II type 1 receptor-associated protein 1 in rats suffering from heat stroke. Int J Mol Med 2014; 34:1699-705. [DOI: 10.3892/ijmm.2014.1950] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2014] [Accepted: 09/12/2014] [Indexed: 11/05/2022] Open
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23
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Castillo-Badillo JA, Cabrera-Wrooman A, García-Sáinz JA. Visualizing G protein-coupled receptors in action through confocal microscopy techniques. Arch Med Res 2014; 45:283-93. [PMID: 24751328 DOI: 10.1016/j.arcmed.2014.03.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 03/26/2014] [Indexed: 01/21/2023]
Abstract
G protein-coupled receptors constitute one of the most abundant entities in cellular communication. Elucidation of their structure and function as well as of their regulation began 30-40 years ago and the advance has markedly increased during the last 15 years. They participate in a plethora of cell functions such as regulation of metabolic fluxes, contraction, secretion, differentiation, or proliferation, and in essentially all activities of our organism; these receptors are targets of a large proportion of prescribed and illegal drugs. Fluorescence techniques have been used to study receptors for many years. The experimental result was usually a two-dimensional (2D) micrograph. Today, the result can be a spatiotemporal (four-dimensional, 4D) movie. Advances in microscopy, fluorescent protein design, and computer-assisted analysis have been of great importance to increase our knowledge on receptor regulation and function and create opportunities for future research. In this review we briefly depict the state of the art of the G protein-coupled receptor field and the methodologies used to study G protein-coupled receptor location, trafficking, dimerization, and other types of receptor-protein interaction. Fluorescence techniques now permit the capture of receptor images with high resolution and, together with a variety of fluorescent dyes that color organelles (such as the plasma membrane or the nucleus) or the cytoskeleton, allow researchers to obtain a much clearer idea of what is taking place at the cellular level. These developments are changing the way we explore cell communication and signal transduction, permitting deeper understanding of the physiological and pathophysiological processes.
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Affiliation(s)
- Jean A Castillo-Badillo
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México, D.F., Mexico
| | | | - J Adolfo García-Sáinz
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México, D.F., Mexico.
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24
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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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25
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Ramkhelawon B, Rivas D, Lehoux S. Shear stress activates extracellular signal-regulated kinase 1/2 via the angiotensin II type 1 receptor. FASEB J 2013; 27:3008-16. [PMID: 23585396 DOI: 10.1096/fj.12-222299] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Mechanical factors such as strain, pressure, and shear stress are key regulators of cell function, but the molecular mechanisms underlying the detection and responses to such stimuli are poorly understood. Whether the angiotensin II (AngII) AT1 receptor (AT1R) transduces shear stress in endothelial cells (ECs) is unknown. We exposed human umbilical cord endothelial cells (HUVECs) to a shear stress of 0 (control) or 15 dyn/cm(2) for 5 or 10 min. The colocalization of AT1R with caveolin-1 (Cav1), endosomal markers Rab5, EEA1, and Rab7, and lysosomal marker Lamp-1 increased in shear stimulated cells, detected by immunocytochemistry. Shear stress reduced labeling of wild-type mouse ECs (18±3% of unsheared control, P<0.01) but not Cav1(-/-) ECs (90±10%) with fluorescent AngII, confirming that internalization of AT1R requires Cav1. Shear stress activated ERK1/2 2-fold (P<0.01), which was prevented by the AT1R blocker losartan. NADPH oxidase inhibition with apocynin prevented both the colocalization of AT1R with Cav1 and the induction of ERK1/2 by shear stress. Moreover, shear-dependent ERK1/2 activation was minimal in CHO cells expressing an AT1Ra mutant that does not internalize, compared with cells expressing wild-type AT1Ra (P<0.05). Hence, AT1R may be an important transducer of shear stress-dependent activation of ERK1/2.
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26
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Torres-Tirado D, Ramiro-Diaz J, Knabb MT, Rubio R. Molecular weight of different angiotensin II polymers directly determines: density of endothelial membrane AT1 receptors and coronary vasoconstriction. Vascul Pharmacol 2013; 58:346-55. [PMID: 23511517 DOI: 10.1016/j.vph.2013.03.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Revised: 03/07/2013] [Accepted: 03/10/2013] [Indexed: 01/30/2023]
Abstract
We have shown that angiotensin II (Ang II) does not diffuse across the vessel wall, remaining intravascularly confined and acting solely on the coronary endothelial luminal membrane (CELM) receptors. A sustained intracoronary infusion of Ang II causes transient coronary vasoconstriction (desensitization) due to membrane internalization of CELM Ang II type 1 receptors (CELM-AT1R). In contrast, sustained intracoronary infusion of a non-diffusible polymer of Ang II (Ang II-Pol, 15,000 kDa) causes a sustained vasoconstriction by preventing CELM-AT1R internalization. In addition, a sustained intracoronary infusion of Ang II leads to a depressed response following a secondary Ang II administration (tachyphylaxis) that is reversed by Ang II-Pol. These findings led us to hypothesize that the rate of desensitization, tachyphylaxis, and AT1R internalization were dependent on Ang II-Pol molecular weight. To test this hypothesis, we synthesized Ang II-Pols of the following molecular weights (in kDa): 1.3, 2.7, 11, 47, 527, 3270 and 15,000. Vasoconstriction was measured following intracoronary infusion of Ang II-Pols in Langendorff-perfused guinea pig hearts at constant flow. The CELM protein fraction was extracted using the silica pellicle technique at different time points in order to determine the rate of AT1R internalization following each Ang II-Pol infusion. CELM-AT1R density was quantified by Western blot. We found that the rate of desensitization and the tachyphylaxis effect varied inversely with the molecular weight of the Ang II-Pols. Inversely proportional to the molecular weight of Ang II-Pol the CELM-AT1R density decreases over time. These results indicate that the mechanism responsible for the decreased rate of desensitization and tachyphylaxis by higher molecular weight Ang II polymers is due to reduction in the rate of CELM-AT1R internalization. These Ang II polymers would be valuable tools for studying the relationship between AT1R internalization and physiological effects.
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27
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Castrop H. Angiotensin receptor-associated proteins: local modulators of the renin–angiotensin system. Pflugers Arch 2012; 465:111-9. [DOI: 10.1007/s00424-012-1113-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Revised: 04/30/2012] [Accepted: 05/02/2012] [Indexed: 01/11/2023]
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28
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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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29
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Ray P, Mihalko LA, Coggins NL, Moudgil P, Ehrlich A, Luker KE, Luker GD. Carboxy-terminus of CXCR7 regulates receptor localization and function. Int J Biochem Cell Biol 2012; 44:669-78. [PMID: 22300987 DOI: 10.1016/j.biocel.2012.01.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Revised: 01/10/2012] [Accepted: 01/16/2012] [Indexed: 01/09/2023]
Abstract
Chemokine receptor CXCR7 is essential for normal development, and this receptor promotes initiation and progression of diseases including cancer and autoimmunity. To understand normal and pathologic functions of CXCR7 and advance development of therapeutic agents, there is a need to define structural domains that regulate this receptor. We generated mutants of CXCR7 with deletion of different lengths of the predicted intracellular tail and analyzed effects on CXCR7 signaling and function in cell-based assays. While wild-type CXCR7 predominantly localized to intracellular vesicles, progressive deletion of the carboxy terminus redistributed the receptor to the plasma membrane. Truncating the intracellular tail of CXCR7 did not alter binding to CXCL12, but mutant receptors had reduced scavenging of this chemokine. Using a firefly luciferase complementation system, we established that deletions of the carboxy terminus decreased basal interactions and eliminated ligand-dependent recruitment of the scaffolding protein β-arrestin-2 to receptors. Deleting the carboxy terminus of CXCR7 impaired constitutive internalization of the receptor and reduced activation of ERK1/2 by CXCL12-CXCR7. Inhibiting dynamin, a molecule required for internalization of CXCR7, increased ligand-dependent association of the receptor with β-arrestin-2 and enhanced activation of ERK1/2. These studies establish mechanisms of action for CXCR7 and establish the intracellular tail of CXCR7 as a critical determinant of receptor trafficking, chemokine scavenging, and signaling.
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Affiliation(s)
- Paramita Ray
- Center for Molecular Imaging, Department of Radiology, University of Michigan Medical School, Ann Arbor, MI 48109-2200, USA
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30
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The role of palmitoylation in directing dopamine D1 receptor internalization through selective endocytic routes. Biochem Biophys Res Commun 2011; 405:445-9. [PMID: 21241663 DOI: 10.1016/j.bbrc.2011.01.050] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2011] [Accepted: 01/12/2011] [Indexed: 02/02/2023]
Abstract
We previously determined that D1 receptors can endocytose through caveolae, a subset of lipid rafts, in addition to internalization via a clathrin-dependent pathway. In this report, we investigated the potential role that palmitoylation might have on directing D1 receptor internalization through either a clathrin or caveolar-dependent route. Through whole cell binding analysis and sucrose gradient fractionation studies, we demonstrated that although palmitoylation of the D1 receptor was not required for agonist-independent localization to caveolae, agonist induced internalization kinetics of a de-palmitoylated D1 receptor were accelerated ∼8-fold in comparison to wild-type D1 receptor and were very similar to that observed for clathrin-dependent D1 receptor internalization. Additionally, inhibition of the clathrin mediated pathway led to significant attenuation in the extent of agonist induced internalization of the de-palmitoylated D1 receptor, suggesting the de-palmitoylated D1 receptor was directed to a clathrin-dependent internalization pathway. Taken together, these data suggest that palmitoylation may be involved in directing agonist-dependent D1 receptor internalization through selective endocytic routes.
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31
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Thangaraju A, Sawyer GW. Comparison of the kinetics and extent of muscarinic M1-M5 receptor internalization, recycling and downregulation in Chinese hamster ovary cells. Eur J Pharmacol 2010; 650:534-43. [PMID: 21044619 DOI: 10.1016/j.ejphar.2010.10.054] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Revised: 10/04/2010] [Accepted: 10/16/2010] [Indexed: 11/18/2022]
Abstract
We characterized agonist-induced internalization, recycling and downregulation of each muscarinic receptor subtype (M(1)-M(5)) stably expressed in Chinese hamster ovary (CHO) cells. The radioligands [(3)H]QNB and [(3)H]NMS were used to measure the total and plasma membrane populations of muscarinic receptors, respectively. Following carbachol treatment (1 mM), the rank orders for the rate of carbachol-induced internalization of the muscarinic subtypes were M(2)>M(4)=M(5)>M(3)=M(1), respectively. Unlike the M(2) receptor, M(1), M(3), M(4) and M(5) receptors recycled back to the plasma membrane after 1 h carbachol treatment. The receptor downregulation elicited to 24h carbachol treatment was similar for M(2), M(3), M(4) and M(5) receptors, whereas that for the M(1) receptor was greater. Our results indicate that there are subtype-specific differences in the rate and extent of agonist-induced muscarinic receptor internalization, recycling and downregulation in CHO cells.
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Affiliation(s)
- Arunkumar Thangaraju
- Oklahoma State University, Center for Health Sciences, College of Osteopathic Medicine, Department of Biochemistry and Microbiology, 1111 W. 17th Street, Tulsa, OK 74107-1898, USA
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32
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Zheng H, Zeng Y, Chu J, Kam AY, Loh HH, Law PY. Modulations of NeuroD activity contribute to the differential effects of morphine and fentanyl on dendritic spine stability. J Neurosci 2010; 30:8102-10. [PMID: 20554861 PMCID: PMC2913383 DOI: 10.1523/jneurosci.6069-09.2010] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2009] [Revised: 03/25/2010] [Accepted: 03/30/2010] [Indexed: 01/14/2023] Open
Abstract
The cellular level of neurogenic differentiation 1 (NeuroD) is modulated differentially by mu-opioid receptor agonists; fentanyl increases NeuroD level by reducing the amount of microRNA-190 (miR-190), an inhibitor of NeuroD expression, whereas morphine does not alter NeuroD level. In the current study, NeuroD activity was demonstrated to be also under agonist-dependent regulation. After 3 d of treatment, morphine and fentanyl decreased the activity of the Ca(2+)/calmodulin-dependent protein kinase II alpha (CaMKIIalpha), which phosphorylates and activates NeuroD. Because NeuroD activity is determined by both the CaMKIIalpha activity and the cellular NeuroD level, the overall NeuroD activity was reduced by morphine, but maintained during fentanyl treatment. The differential effects of agonists on NeuroD activity were further confirmed by measuring the mRNA levels of four NeuroD downstream targets: doublecortin, Notch1, neurogenic differentiation 4, and Roundabout 1. Decreased dendritic spine stability and mu-opioid receptor signaling capability were also observed when NeuroD activity was attenuated by miR-190 overexpression or treatment with KN93, a CaMKIIalpha inhibitor. The decrease could be rescued by NeuroD overexpression, which restored NeuroD activity to the basal level. Furthermore, elevating NeuroD activity attenuated the morphine-induced decrease in dendritic spine stability. Therefore, by regulating NeuroD activity, mu-opioid receptor agonists modulate the stability of dendritic spines.
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MESH Headings
- Animals
- Basic Helix-Loop-Helix Transcription Factors/genetics
- Basic Helix-Loop-Helix Transcription Factors/metabolism
- Benzylamines/pharmacology
- Calcium-Calmodulin-Dependent Protein Kinase Type 2/metabolism
- Cells, Cultured
- Dendritic Spines/drug effects
- Dendritic Spines/physiology
- Dose-Response Relationship, Drug
- Doublecortin Domain Proteins
- Doublecortin Protein
- Enzyme Inhibitors/pharmacology
- Fentanyl/pharmacology
- Gene Expression Regulation/drug effects
- Green Fluorescent Proteins/genetics
- Hippocampus/cytology
- Microtubule-Associated Proteins/genetics
- Microtubule-Associated Proteins/metabolism
- Morphine/pharmacology
- Narcotics/pharmacology
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/metabolism
- Neurons/drug effects
- Neurons/metabolism
- Neurons/ultrastructure
- Neuropeptides/genetics
- Neuropeptides/metabolism
- Phosphorylation/drug effects
- RNA, Messenger/metabolism
- Rats
- Receptor, Notch1/genetics
- Receptor, Notch1/metabolism
- Receptors, Immunologic/genetics
- Receptors, Immunologic/metabolism
- Receptors, Opioid, mu/metabolism
- Sulfonamides/pharmacology
- Time Factors
- Transduction, Genetic/methods
- Roundabout Proteins
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Affiliation(s)
- Hui Zheng
- Department of Pharmacology, University of Minnesota, Minneapolis, Minnesota 55455-0217, USA.
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33
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Davis CN, Bradley SR, Schiffer HH, Friberg M, Koch K, Tolf BR, Bonhaus DW, Lameh J. Differential regulation of muscarinic M1 receptors by orthosteric and allosteric ligands. BMC Pharmacol 2009; 9:14. [PMID: 19951444 PMCID: PMC2794843 DOI: 10.1186/1471-2210-9-14] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Accepted: 12/02/2009] [Indexed: 11/13/2022] Open
Abstract
Background Activation of muscarinic M1 receptors is mediated via interaction of orthosteric agonists with the acetylcholine binding site or via interaction of allosteric agonists with different site(s) on the receptor. The focus of the present study was to determine if M1 receptors activated by allosteric agonists undergo the same regulatory fate as M1 receptors activated by orthosteric agonists. Results The orthosteric agonists carbachol, oxotremorine-M and pilocarpine were compared to the allosteric agonists AC-42, AC-260584, N-desmethylclozapine and xanomeline. All ligands activated M1 receptors and stimulated interaction of the receptors with β-arrestin-1. All ligands reduced cell surface binding and induced the loss of total receptor binding. Receptor internalization was blocked by treatment with hypertonic sucrose indicating that all ligands induced formation of clathrin coated vesicles. However, internalized receptors recycled to the cell surface following removal of orthosteric, but not allosteric agonists. Whereas all ligands induced loss of cell surface receptor binding, no intracellular vesicles could be observed after treatment with AC-260584 or xanomeline. Brief stimulation of M1 receptors with AC-260584 or xanomeline resulted in persistent activation of M1 receptors, suggesting that continual receptor signaling might impede or delay receptor endocytosis into intracellular vesicles. Conclusion These results indicate that allosteric agonists differ from orthosteric ligands and among each other in their ability to induce different regulatory pathways. Thus, signaling and regulatory pathways induced by different allosteric ligands are ligand specific.
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Affiliation(s)
- Christopher N Davis
- ACADIA Pharmaceuticals Inc, 3911 Sorrento Valley Blvd, San Diego, CA 92121, USA.
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Wright JW, Harding JW. The angiotensin AT4 receptor subtype as a target for the treatment of memory dysfunction associated with Alzheimer's disease. J Renin Angiotensin Aldosterone Syst 2009; 9:226-37. [PMID: 19126664 DOI: 10.1177/1470320308099084] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Over recent years antihypertensive drugs, particularly angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs), have been reported to have beneficial effects upon cognitive impairment. Such findings suggest that pharmacological manipulation of angiotensin ligands may be of clinical importance in slowing or halting the cognitive deterioration seen in vascular dementia and Alzheimer's disease. The mechanism(s) underlying these improvements in cognitive function remains unclear; however, important leads are emerging. The angiotensin AT4 receptor subtype, discovered by our laboratory in 1992, influences several important behaviours and physiologies, including learning and memory, and may play a role in this cognitive improvement. This review initially describes the therapeutic drugs approved by the Federal Drug Administration and new approaches presently being developed to treat Alzheimer's disease-induced cognitive impairment. Next, the biologically-active angiotensin ligands and their respective receptor subtypes are discussed, followed by the roles of angiotensin II, angiotensin IV, ACE inhibitors and ARBs in cognitive function. We conclude with a working hypothesis concerning the importance of the AT4 receptor subtype as a new potential drug target for the treatment of Alzheimer's disease-associated memory loss.
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Affiliation(s)
- John W Wright
- Department of Psychology, Veterinary and Comparative Anatomy, Pharmacology, and Physiology, Washington State University, P.O. Box 644820, Pullman, WA 99164-4820, USA.
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Garrido AM, Griendling KK. NADPH oxidases and angiotensin II receptor signaling. Mol Cell Endocrinol 2009; 302:148-58. [PMID: 19059306 PMCID: PMC2835147 DOI: 10.1016/j.mce.2008.11.003] [Citation(s) in RCA: 280] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2008] [Revised: 10/17/2008] [Accepted: 11/03/2008] [Indexed: 02/07/2023]
Abstract
Over the last decade many studies have demonstrated the importance of reactive oxygen species (ROS) production by NADPH oxidases in angiotensin II (Ang II) signaling, as well as a role for ROS in the development of different diseases in which Ang II is a central component. In this review, we summarize the mechanism of activation of NADPH oxidases by Ang II and describe the molecular targets of ROS in Ang II signaling in the vasculature, kidney and brain. We also discuss the effects of genetic manipulation of NADPH oxidase function on the physiology and pathophysiology of the renin-angiotensin system.
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Savić R, Azzam T, Eisenberg A, Nedev H, Rosenberg L, Maysinger D. Block-copolymer micelles as carriers of cell signaling modulators for the inhibition of JNK in human islets of Langerhans. Biomaterials 2009; 30:3597-604. [PMID: 19342094 DOI: 10.1016/j.biomaterials.2009.03.028] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2009] [Accepted: 03/11/2009] [Indexed: 10/21/2022]
Abstract
Here we investigate the potential of PCL-b-PEO micelles in preventing the cell death of isolated human islets of Langerhans. PCL-b-PEO micelles were loaded with c-Jun NH2-terminal kinases inhibitor SP600125 to rescue the isolated islets. Mechanistic studies of the uptake were conducted in PC12 cells. Incorporation of SP600125 afforded 8.2 fold greater solubility of SP600125 in micelle suspension. To investigate the effectiveness of micelle-incorporated SP600125 in preventing the islet cell death, we challenged the islets with TNF-alpha, IL-1, and IFN gamma. Micelle-incorporated SP600125 did not lose its inhibitory activity during incorporation into micelles, and it protected the islets against cytokine-induced loss of viability to the same extent as control SP600125. Moreover, the concentration of micelle-incorporated SP600125 used was 13-fold lower, demonstrating the greater efficacy of micelle delivered SP600125. Micelles maintained their cytoplasmic distribution without detectable nuclear localization in islets. The inhibition of JNK was confirmed by western blots. This study suggests that micelle-based intracellular delivery of potent, poorly water soluble, cell-death-pathway inhibitors may represent a valuable addition to established delivery of cytocidal block-copolymer micelle-incorporated bioactives.
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Affiliation(s)
- Radoslav Savić
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada
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37
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38
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Xu Y, Henning RH, Sandovici M, van der Want JJ, van Gilst WH, Buikema H. Enhanced myogenic constriction of mesenteric artery in heart failure relates to decreased smooth muscle cell caveolae numbers and altered AT1- and epidermal growth factor-receptor function. Eur J Heart Fail 2009; 11:246-55. [PMID: 19147448 DOI: 10.1093/eurjhf/hfn027] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
AIMS We previously showed that enhanced myogenic constriction (MC) of peripheral resistance arteries involves active AT(1) receptors in chronic heart failure (CHF). Recent data suggest both transactivation of EGF receptors and caveolae-like microdomains to be implicated in the activity of AT(1) receptors. Thus, we assessed their roles in increased MC in mesenteric arteries of CHF rats. METHODS AND RESULTS Male Wistar rats underwent myocardial infarction to induce CHF and were sacrificed after 12 weeks. The number of caveolae in smooth muscle cells (SMC) of mesenteric arteries of CHF rats was decreased by 43.6 +/- 4.0%, this was accompanied by increased MC, which was fully normalized to the level of sham by antagonists of the AT(1)-receptor (losartan) or EGF-receptor (AG1478). Acute disruption of caveolae in sham rats affected caveolae numbers and MC to a similar extent as CHF, however MC was only reversed by the antagonist of the EGF-receptor, but not by the AT(1)-receptor antagonist. Further, in sham rats, MC was increased by a sub-threshold concentration of angiotensin II and reversed by both AT(1)- as well as EGF-receptor inhibition. In contrast, increased MC by a sub-threshold concentration of EGF was only reversed by EGF receptor inhibition. CONCLUSION These findings provide the first evidence that decreased SMC caveolae numbers are involved in enhanced MC in small mesenteric arteries, by affecting AT(1)- and EGF-receptor function. This suggests a novel mechanism involved in increased peripheral resistance in CHF.
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Affiliation(s)
- Ying Xu
- Department of Clinical Pharmacology, Groningen University Institute for Drug Exploration (GUIDE), University Medical Center Groningen, University of Groningen, Groningen, the Netherlands.
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Finger EC, Lee NY, You HJ, Blobe GC. Endocytosis of the type III transforming growth factor-beta (TGF-beta) receptor through the clathrin-independent/lipid raft pathway regulates TGF-beta signaling and receptor down-regulation. J Biol Chem 2008; 283:34808-18. [PMID: 18845534 PMCID: PMC2596377 DOI: 10.1074/jbc.m804741200] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2008] [Revised: 09/26/2008] [Indexed: 11/06/2022] Open
Abstract
Transforming growth factor-beta (TGF-beta) signals through three highly conserved cell surface receptors, the type III TGF-beta receptor (T beta RIII), the type II TGF-beta receptor (T beta RII), and the type I TGF-beta receptor (T beta RI) to regulate diverse cellular processes including cell proliferation, differentiation, migration, and apoptosis. Although T beta RI and T beta RII undergo ligand-independent endocytosis by both clathrin-mediated endocytosis, resulting in enhanced signaling, and clathrin-independent endocytosis, resulting in receptor degradation, the mechanism and function of T beta RIII endocytosis is poorly understood. T beta RIII is a heparan sulfate proteoglycan with a short cytoplasmic tail that functions as a TGF-beta superfamily co-receptor, contributing to TGF-beta signaling through mechanisms yet to be fully defined. We have reported previously that T beta RIII endocytosis, mediated by a novel interaction with beta arrestin-2, results in decreased TGF-beta signaling. Here we demonstrate that T beta RIII undergoes endocytosis in a ligand and glycosaminoglycan modification-independent and cytoplasmic domain-dependent manner, with the interaction of Thr-841 in the cytoplasmic domain of T beta RIII with beta-arrestin2 enhancing T beta RIII endocytosis. T beta RIII undergoes both clathrin-mediated and clathrin-independent endocytosis. Importantly, inhibition of the clathrin-independent, lipid raft pathway, but not of the clathrin-dependent pathway, results in decreased TGF-beta1 induced Smad2 and p38 phosphorylation, supporting a specific role for clathrin-independent endocytosis of T beta RIII in regulating both Smad-dependent and Smad-independent TGF-beta signaling.
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Affiliation(s)
- Elizabeth C. Finger
- Departments of Pharmacology and Cancer
Biology and Medicine, Duke University Medical
Center, Durham, North Carolina 27708
| | - Nam Y. Lee
- Departments of Pharmacology and Cancer
Biology and Medicine, Duke University Medical
Center, Durham, North Carolina 27708
| | - Hye-jin You
- Departments of Pharmacology and Cancer
Biology and Medicine, Duke University Medical
Center, Durham, North Carolina 27708
| | - Gerard C. Blobe
- Departments of Pharmacology and Cancer
Biology and Medicine, Duke University Medical
Center, Durham, North Carolina 27708
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40
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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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41
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Proulx CD, Holleran BJ, Boucard AA, Escher E, Guillemette G, Leduc R. Mutational analysis of the conserved Asp2.50 and ERY motif reveals signaling bias of the urotensin II receptor. Mol Pharmacol 2008; 74:552-61. [PMID: 18509066 DOI: 10.1124/mol.108.045054] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Class A (rhodopsin-like) G protein-coupled receptors possess conserved residues and motifs that are important for their specific activity. In the present study, we examined the role of residue Asp97(2.50) as well as residues Glu147(3.49), Arg148(3.50), and Tyr149(3.51) of the ERY motif on the functionality of the urotensin II receptor (UT). Mutations D97(2.50)A, R148(3.50)A, and R148(3.50)H abolished the ability of UT to activate phospholipase C, whereas mutations E147(3.49)A and Y149(3.51)A reduced the ability to activate PLC by 50%. None of the mutants exhibited constitutive activity. However, R148(3.50)A and R148(3.50)H promoted ERK1/2 activation, which was abolished by 4-(3-chloroanilino)-6,7-dimethoxyquinazoline (AG1478), an inhibitor of epidermal growth factor receptor (EGFR) tyrosine kinase activity. Both these mutants were capable of directly activating EGFR, which confirmed that they activated the mitogen-activated protein kinase (MAPK) pathway by a Galpha(q/11)-independent transactivation of EGFR. The D97(2.50)A, R148(3.50)A, and R148(3.50)H mutants did not readily internalize and did not promote translocation or colocalize with beta-arrestin2-GFP. Finally, the agonist-induced internalization of the E147(3.49)A mutant receptor was significantly increased compared with wild-type receptor. This study highlights the major contribution of the conserved Asp(2.50) residue to the functionality of the UT receptor. The Arg residue in the ERY motif of UT is an important structural element in signaling crossroads that determine whether Galpha(q/11)-dependent and -independent events can occur.
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Affiliation(s)
- Christophe D Proulx
- Department of Pharmacology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, J1H5N4 ON, Canada
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42
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Proulx CD, Holleran BJ, Lavigne P, Escher E, Guillemette G, Leduc R. Biological properties and functional determinants of the urotensin II receptor. Peptides 2008; 29:691-9. [PMID: 18155322 DOI: 10.1016/j.peptides.2007.10.027] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2007] [Revised: 10/12/2007] [Accepted: 10/19/2007] [Indexed: 02/07/2023]
Abstract
The urotensin II receptor (UT) is a member of the G protein-coupled receptor (GPCR) family and binds the cyclic undecapeptide urotensin II (U-II) as well as the octapeptide urotensin II-related peptide (URP). The active UT mediates pleiotropic effects through various signal transduction pathways, including coupling to G proteins and activating the mitogen-activated protein kinase pathway. Several highly conserved residues and motifs of class A GPCRs that are important for activity are found in UT. This review highlights some of the putative roles of these motifs in the binding, activation and desensitization of UT.
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Affiliation(s)
- Christophe D Proulx
- Department of Pharmacology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, 3001, 12th Avenue North, Sherbrooke, Quebec, J1H 5N4 Canada
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Saito M, Shinohara Y, Sasaki H, Netsu Y, Yoshida M, Nakahata N. Type 1 angiotensin receptor (AT1-R)-mediated decrease in type 2 angiotensin receptor mRNA level is dependent on Gq and extracellular signal-regulated kinase 1//2 in AT1-R-transfected PC12 cells. J Neuroendocrinol 2008; 20:299-308. [PMID: 18208547 DOI: 10.1111/j.1365-2826.2008.01646.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Angiotensin II (Ang II) functions through two major Ang II receptor subtypes, type 1 (AT1-R) and type 2 (AT2-R), both of which are classified to be G protein-coupled receptors. AT2-R is highly expressed at the fetal stage, and in heart remodelling and brain ischaemia; therefore, it is important to clarify the regulatory mechanisms of AT2-R expression. Although AT1-R is generally believed to modulate AT2-R expression in some tissues or cells, the exact mechanism remains to be clarified. In the present study, we examined the effect of AT1-R stimulation on expression of endogenous rat AT2-R (rAT2-R) in AT1-R-transfected PC12 cells. rAT2-R mRNA and protein expression were decreased by Ang II in PC12 cells transfected with rAT1A-R in a time-dependent manner, mediated through a decline in mRNA stability. The C-terminus of G protein-coupled receptor (GPCR) is important for GPCR-mediated signal transduction. Therefore, we used C-terminus-deleted human AT1-R (hAT1-327STOP), which is thought to be a nondesensitised mutant of hAT1-R. As a result, Ang II decreased rAT2-R mRNA expression to a greater extent in cells transfected with hAT1-327STOP than with wild-type hAT1-R. The decrease was completely reversed by AT1-R antagonist candesartan, G(q) inhibitor YM254980, and mitogen-activated protein kinase (MAPK) kinase 1/2 inhibitor U0126, but not by pertussis toxin, which uncouples the receptor with G(i), or p38 MAPK inhibitor SB203580. We suggest, possibly for the first time, that the hAT1-R/G(q)/extracellular signal-regulated kinase 1/2 pathway is involved in the down-regulation of AT2-R using PC12 cells transfected with AT1-R.
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MESH Headings
- Angiotensin II/pharmacology
- Animals
- Down-Regulation
- GTP-Binding Protein alpha Subunits, Gq-G11/physiology
- Gene Expression Regulation, Neoplastic/drug effects
- Mitogen-Activated Protein Kinase 1/physiology
- Mitogen-Activated Protein Kinase 3/physiology
- PC12 Cells
- Protein Structure, Tertiary/physiology
- RNA Stability/drug effects
- RNA, Messenger/metabolism
- Rats
- Receptor, Angiotensin, Type 1/chemistry
- Receptor, Angiotensin, Type 1/genetics
- Receptor, Angiotensin, Type 1/physiology
- Receptor, Angiotensin, Type 2/genetics
- Receptor, Angiotensin, Type 2/metabolism
- Signal Transduction/physiology
- Transfection
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Affiliation(s)
- M Saito
- Department of Cellular Signalling, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
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Mogi M, Iwai M, Horiuchi M. Emerging Concepts of Regulation of Angiotensin II Receptors. Arterioscler Thromb Vasc Biol 2007; 27:2532-9. [PMID: 17717300 DOI: 10.1161/atvbaha.107.144154] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Angiotensin (Ang) II exerts its important physiological functions through 2 distinct receptor subtypes, type 1 (AT
1
) and type 2 (AT
2
) receptors. Recently, new evidence has accumulated showing the existence of several novel receptor interacting proteins and various angiotensin II receptor activation mechanisms beyond the classical actions of receptors for Ang II. These associated proteins could contribute not only to Ang II receptors’ functions, but also to influencing pathophysiological states. Receptor dimerization of Ang II receptors such as homodimer, heterodimer, and complex formation with other G protein-coupled receptors has also been focused on as a new mechanism of their activation or inactivation. Moreover, ligand-independent receptor activation systems such as mechanical stretch for the AT
1
receptor have also been revealed. These emerging concepts of regulation of Ang II receptors and a new insight into future drug discovery are discussed in this review.
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MESH Headings
- Adaptor Proteins, Signal Transducing/metabolism
- Angiotensin II/metabolism
- Angiotensin II Type 1 Receptor Blockers/pharmacology
- Angiotensin II Type 1 Receptor Blockers/therapeutic use
- Animals
- Antihypertensive Agents/pharmacology
- Antihypertensive Agents/therapeutic use
- Autoantibodies/metabolism
- Dimerization
- Drug Inverse Agonism
- GTP-Binding Proteins/metabolism
- Humans
- Hypertension/drug therapy
- Hypertension/metabolism
- Kruppel-Like Transcription Factors/metabolism
- Ligands
- Membrane Transport Proteins/metabolism
- Multiprotein Complexes/metabolism
- Protein Conformation
- Protein Tyrosine Phosphatase, Non-Receptor Type 6/metabolism
- Receptor, Angiotensin, Type 1/chemistry
- Receptor, Angiotensin, Type 1/drug effects
- Receptor, Angiotensin, Type 1/immunology
- Receptor, Angiotensin, Type 1/metabolism
- Receptor, Angiotensin, Type 2/agonists
- Receptor, Angiotensin, Type 2/chemistry
- Receptor, Angiotensin, Type 2/metabolism
- Signal Transduction/drug effects
- Tumor Suppressor Proteins/metabolism
- Ubiquitin-Conjugating Enzymes/metabolism
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Affiliation(s)
- Masaki Mogi
- FAHA, Professor and Chairman, Department of Molecular Cardiovascular Biology and Pharmacology, Ehime University, Graduate School of Medicine, Shitsukawa, Tohon, Ehime 791-0295, Japan
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Involvement of insulin-regulated aminopeptidase in the effects of the renin–angiotensin fragment angiotensin IV: a review. Heart Fail Rev 2007; 13:321-37. [DOI: 10.1007/s10741-007-9062-x] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2007] [Accepted: 10/16/2007] [Indexed: 10/22/2022]
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Choi H, Leto TL, Hunyady L, Catt KJ, Bae YS, Rhee SG. Mechanism of angiotensin II-induced superoxide production in cells reconstituted with angiotensin type 1 receptor and the components of NADPH oxidase. J Biol Chem 2007; 283:255-267. [PMID: 17981802 DOI: 10.1074/jbc.m708000200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The mechanism of angiotensin II (Ang II)-induced superoxide production was investigated with HEK293 or Chinese hamster ovary cells reconstituted with the angiotensin type 1 receptor (AT(1)R) and NADPH oxidase (either Nox1 or Nox2) along with a pair of adaptor subunits (either NOXO1 with NOXA1 or p47(phox) with p67(phox)). Ang II enhanced the activity of both Nox1 and Nox2 supported by either adaptor pair, with more effective activation of Nox1 in the presence of NOXO1 and NOXA1 and of Nox2 in the presence of p47(phox) and p67(phox). Expression of several AT(1)R mutants showed that interaction of the receptor with G proteins but not that with beta-arrestin or with other proteins (Jak2, phospholipase C-gamma1, SH2 domain-containing phosphatase 2) that bind to the COOH-terminal region of AT(1)R, was necessary for Ang II-induced superoxide production. The effects of constitutively active alpha subunits of G proteins and of various pharmacological agents implicated signaling by a pathway comprising AT(1)R, Galpha(q/11), phospholipase C-beta, and protein kinase C as largely, but not exclusively, responsible for Ang II-induced activation of Nox1 and Nox2 in the reconstituted cells. A contribution of Galpha(12/13), phospholipase D, and phosphatidyl-inositol 3-kinase to Ang II-induced superoxide generation was also suggested, whereas Src and the epidermal growth factor receptor did not appear to participate in this effect of Ang II. In reconstituted cells stimulated with Ang II, Nox2 exhibited a more sensitive response than Nox1 to the perturbation of protein kinase C, phosphatidylinositol 3-kinase, or the small GTPase Rac1.
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Affiliation(s)
- Hyun Choi
- Division of Life and Pharmaceutical Sciences, Ewha Womans University, Seoul 120-750, Korea
| | - Thomas L Leto
- Laboratory of Host Defenses, NIAID, National Institutes of Health, Bethesda, Maryland 20892
| | - László Hunyady
- Department of Physiology, Semmelweis University, H-1088 Budapest, Hungary
| | - Kevin J Catt
- Endocrinology and Reproduction Research Branch, NICHD, National Institutes of Health, Bethesda, Maryland 20892
| | - Yun Soo Bae
- Division of Life and Pharmaceutical Sciences, Ewha Womans University, Seoul 120-750, Korea.
| | - Sue Goo Rhee
- Division of Life and Pharmaceutical Sciences, Ewha Womans University, Seoul 120-750, Korea.
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Lanckmans K, Stragier B, Sarre S, Smolders I, Michotte Y. Nano-LC-MS/MS for the monitoring of angiotensin IV in rat brain microdialysates: Limitations and possibilities. J Sep Sci 2007; 30:2217-24. [PMID: 17688302 DOI: 10.1002/jssc.200700159] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
To broaden our knowledge about the central role of the angiotensin IV (Ang IV) peptide, we aimed to monitor its extracellular concentration in the brain using in vivo microdialysis. Ang IV was measured in the dialysates using a previously developed nano-LC-MS/MS assay with an LOD of 50 pM. Using this assay, baseline levels of Ang IV in dialysates from different brain structures were undetectable. However, immediately after microdialysis probe insertion, Ang IV could be detected in a concentration that varied between 120 and 187 pM. Using the zero-net-flux method, the extracellular levels of Ang IV in the striatum were estimated at 46 pM. These data may indicate that Ang IV is mainly present intracellularly. In addition, Ang IV was clearly measurable after striatal perfusion of Ang II. On the other hand, our nano-LC-MS/MS method was successful for the detection of Met-enkephalin and neurotensin in dialysates from the rat. In conclusion, the nano-LC-MS/MS method coupled with microdialysis is well suited to monitor the biologically significant conversion between Ang II and Ang IV in vivo, but physiological extracellular levels of Ang IV appear too low to be detected.
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Affiliation(s)
- Katrien Lanckmans
- Research Group Experimental Pharmacology, Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Vrije Universiteit Brussel, Brussels, Belgium
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Zemskov EA, Mikhailenko I, Strickland DK, Belkin AM. Cell-surface transglutaminase undergoes internalization and lysosomal degradation: an essential role for LRP1. J Cell Sci 2007; 120:3188-99. [PMID: 17711877 DOI: 10.1242/jcs.010397] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Tissue transglutaminase functions as a protein crosslinking enzyme and an integrin-binding adhesion co-receptor for fibronectin on the cell surface. These activities of transglutaminase and the involvement of this protein in cell-matrix adhesion, integrin-mediated signaling, cell migration and matrix organization suggest a precise and efficient control of its cell-surface expression. We report a novel mechanism of regulation of surface transglutaminase through internalization and subsequent lysosomal degradation. Constitutive endocytosis of cell-surface transglutaminase depends on plasma membrane cholesterol and the activity of dynamin-2, and involves both clathrin-coated pits and lipid rafts or caveolae. Furthermore, the key matrix ligands of transglutaminase, fibronectin and platelet-derived growth factor, promote its endocytosis from the cell surface. Our results also indicate that transglutaminase interacts in vitro and on the cell surface with the major endocytic receptor, low-density lipoprotein receptor-related protein 1, and demonstrate the requirement for this receptor in the endocytosis of transglutaminase. Finally, a deficiency of this endocytic receptor or blockade of endo-lysosomal function upregulate transglutaminase expression on the cell surface, leading to increased cell adhesion and matrix crosslinking. These findings characterize a previously unknown pathway of transglutaminase internalization and degradation that might be crucial for regulation of its adhesive and signaling functions on the cell surface and reveal a novel functional link between cell-matrix adhesion and endocytosis.
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Affiliation(s)
- Evgeny A Zemskov
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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Kong MMC, Hasbi A, Mattocks M, Fan T, O'Dowd BF, George SR. Regulation of D1 dopamine receptor trafficking and signaling by caveolin-1. Mol Pharmacol 2007; 72:1157-70. [PMID: 17699686 DOI: 10.1124/mol.107.034769] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
There is accumulating evidence that G protein-coupled receptor signaling is regulated by localization in lipid raft microdomains. In this report, we determined that the D1 dopamine receptor (D1R) is localized in caveolae, a subset of lipid rafts, by sucrose gradient fractionation and confocal microscopy. Through coimmunoprecipitation and bioluminescence resonance energy transfer assays, we demonstrated that this localization was mediated by an interaction between caveolin-1 and D1R in COS-7 cells and an isoform-selective interaction between D1R and caveolin-1alpha in rat brain. We determined that the D1R interaction with caveolin-1 required a putative caveolin binding motif identified in transmembrane domain 7. Agonist stimulation of D1R caused translocation of D1R into caveolin-1-enriched sucrose fractions, which was determined to be a result of D1R endocytosis through caveolae. This was found to be protein kinase A-independent and a kinetically slower process than clathrin-mediated endocytosis. Site-directed mutagenesis of the caveolin binding motif at amino acids Phe313 and Trp318 significantly attenuated caveolar endocytosis of D1R. We also found that these caveolin binding mutants had a diminished capacity to stimulate cAMP production, which was determined to be due to constitutive desensitization of these receptors. In contrast, we found that D1Rs had an enhanced ability to maximally generate cAMP in chemically induced caveolae-disrupted cells. Taken together, these data suggest that caveolae has an important role in regulating D1R turnover and signaling in brain.
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Affiliation(s)
- Michael M C Kong
- Department of Pharmacology, University of Toronto, Medical Sciences Bldg., Rm 4358, Toronto, ON, Canada M5S 1A8
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Hamdan FF, Rochdi MD, Breton B, Fessart D, Michaud DE, Charest PG, Laporte SA, Bouvier M. Unraveling G protein-coupled receptor endocytosis pathways using real-time monitoring of agonist-promoted interaction between beta-arrestins and AP-2. J Biol Chem 2007; 282:29089-100. [PMID: 17675294 DOI: 10.1074/jbc.m700577200] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The most widely studied pathway underlying agonist-promoted internalization of G protein-coupled receptors (GPCRs) involves beta-arrestin and clathrin-coated pits. However, both beta-arrestin- and clathrin-independent processes have also been reported. Classically, the endocytic routes are characterized using pharmacological inhibitors and various dominant negative mutants, resulting sometimes in conflicting results and interpretational difficulties. Here, taking advantage of the fact that beta-arrestin binding to the beta2 subunit of the clathrin adaptor AP-2 (beta2-adaptin) is needed for the beta-arrestin-mediated targeting of GPCRs to clathrin-coated pits, we developed a bioluminescence resonance energy transfer-based approach directly assessing the molecular steps involved in the endocytosis of GPCRs in living cells. For 10 of the 12 receptors tested, including some that were previously suggested to internalize via clathrin-independent pathways, agonist stimulation promoted beta-arrestin 1 and 2 interaction with beta2-adaptin, indicating a beta-arrestin- and clathrin-dependent endocytic process. Detailed analyses of beta-arrestin interactions with both the receptor and beta2-adaptin also allowed us to demonstrate that recruitment of beta-arrestins to the receptor and the ensuing conformational changes are the leading events preceding AP-2 engagement and subsequent clathrin-mediated endocytosis. Among the receptors tested, only the endothelin A and B receptors failed to promote interaction between beta-arrestins and beta2-adaptin. However, both receptors recruited beta-arrestins upon agonist stimulation, suggesting a beta-arrestin-dependent but clathrin-independent route of internalization for these two receptors. In addition to providing a new tool to dissect the molecular events involved in GPCR endocytosis, the bioluminescence resonance energy transfer-based beta-arrestin/beta2-adaptin interaction assay represents a novel biosensor to assess receptor activation.
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Affiliation(s)
- Fadi F Hamdan
- Department of Biochemistry, Groupe de Recherche Universitaire sur le Médicament, Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Québec, Canada
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