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Rivas V, Nogués L, Reglero C, Mayor F, Penela P. Role of G protein-coupled receptor kinase 2 in tumoral angiogenesis. Mol Cell Oncol 2014; 1:e969166. [PMID: 27308373 PMCID: PMC4905215 DOI: 10.4161/23723548.2014.969166] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 08/22/2014] [Accepted: 08/23/2014] [Indexed: 12/26/2022]
Abstract
Downregulation of G protein-coupled receptor kinase 2 (GRK2) in endothelial cells has recently been identified as a relevant event in the tumoral angiogenic switch. Based on the effects of altering GRK2 dosage in cell and animal models, this kinase appears to act as a hub in key signaling pathways involved in vascular stabilization and remodeling. Accordingly, decreased GRK2 expression in endothelial cells accelerates tumor growth in mice by impairing the pericytes ensheathing the vessels, thereby promoting hypoxia and macrophage infiltration. These results raise new questions regarding the mechanisms by which transformed cells trigger the decrease in GRK2 observed in human breast cancer vessels and how GRK2 modulates the interactions between different cell types that occur in the tumor microenvironment.
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Affiliation(s)
- Verónica Rivas
- Departamento de Biología Molecular and Centro de Biología Molecular "Severo Ochoa" (Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid); Universidad Autónoma de Madrid; Madrid, Spain; Instituto de Investigación Sanitaria La Princesa; Madrid, Spain
| | - Laura Nogués
- Departamento de Biología Molecular and Centro de Biología Molecular "Severo Ochoa" (Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid); Universidad Autónoma de Madrid; Madrid, Spain; Instituto de Investigación Sanitaria La Princesa; Madrid, Spain
| | - Clara Reglero
- Departamento de Biología Molecular and Centro de Biología Molecular "Severo Ochoa" (Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid); Universidad Autónoma de Madrid; Madrid, Spain; Instituto de Investigación Sanitaria La Princesa; Madrid, Spain
| | - Federico Mayor
- Departamento de Biología Molecular and Centro de Biología Molecular "Severo Ochoa" (Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid); Universidad Autónoma de Madrid; Madrid, Spain; Instituto de Investigación Sanitaria La Princesa; Madrid, Spain
| | - Petronila Penela
- Departamento de Biología Molecular and Centro de Biología Molecular "Severo Ochoa" (Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid); Universidad Autónoma de Madrid; Madrid, Spain; Instituto de Investigación Sanitaria La Princesa; Madrid, Spain
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Abstract
The interaction between the sympathetic nervous system and the immune system has been documented over the last several decades. In this review, the neuroanatomical, cellular, and molecular evidence for neuroimmune regulation in the maintenance of immune homeostasis will be discussed, as well as the potential impact of neuroimmune dysregulation in health and disease.
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Affiliation(s)
- Caroline J Padro
- The Biomedical Sciences Graduate Program, The Ohio State University Wexner College of Medicine, Columbus, OH 43210, United States.
| | - Virginia M Sanders
- The Department of Molecular Virology, Immunology, and Medical Genetics, The Ohio State University Wexner College of Medicine, Columbus, OH 43210, United States; The Institute of Behavioral Medicine Research, The Ohio State University Wexner College of Medicine, Columbus, OH 43210, United States.
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53
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Li H, Hu D, Fan H, Zhang Y, LeSage GD, Caudle Y, Stuart C, Liu Z, Yin D. β-Arrestin 2 negatively regulates Toll-like receptor 4 (TLR4)-triggered inflammatory signaling via targeting p38 MAPK and interleukin 10. J Biol Chem 2014; 289:23075-23085. [PMID: 25012660 DOI: 10.1074/jbc.m114.591495] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The control of IL-10 production in Toll-like receptor (TLR) signals remains to be elucidated. Here, we report that β-arrestin 2 positively regulates TLR-triggered IL-10 production in a p38 mitogen-activated protein kinase (MAPK)-dependent mechanism. In vitro studies with cells including peritoneal macrophages and HEK293/TLR4 cells have demonstrated that β-arrestin 2 forms complexes with p38 and facilitates p38 activation after lipopolysaccharide (LPS) stimulation. Deficiency of β-arrestin 2 and inhibition of p38 MAPK activity both ameliorate TLR4-stimulated IL-10 response. Additionally, in vivo experiments show that mice lacking β-arrestin 2 produce less amount of IL-10, and are more susceptible to LPS-induced septic shock which is further enhanced by blocking IL-10 signal. These results reveal a novel mechanism by which β-arrestin 2 negatively regulates TLR4-mediated inflammatory reactions.
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Affiliation(s)
- Hui Li
- Department of Internal Medicine, College of Medicine, East Tennessee State University, Johnson City, Tennessee 37614
| | - Dan Hu
- Department of Internal Medicine, College of Medicine, East Tennessee State University, Johnson City, Tennessee 37614,; Department of Neurology, Renmin Hospital of Wuhan University, Wuhan 430060, China
| | - Huimin Fan
- Department of Cardiovascular and Thoracic Surgery, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China, and
| | - Ying Zhang
- Department of Molecular Microbiology and Immunology, Johns Hopkins University, Baltimore, Maryland 21205
| | - Gene D LeSage
- Department of Internal Medicine, College of Medicine, East Tennessee State University, Johnson City, Tennessee 37614
| | - Yi Caudle
- Department of Internal Medicine, College of Medicine, East Tennessee State University, Johnson City, Tennessee 37614
| | - Charles Stuart
- Department of Internal Medicine, College of Medicine, East Tennessee State University, Johnson City, Tennessee 37614
| | - Zhongmin Liu
- Department of Cardiovascular and Thoracic Surgery, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China, and.
| | - Deling Yin
- Department of Internal Medicine, College of Medicine, East Tennessee State University, Johnson City, Tennessee 37614,.
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54
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Walker JKL, DeFea KA. Role for β-arrestin in mediating paradoxical β2AR and PAR2 signaling in asthma. Curr Opin Pharmacol 2014; 16:142-7. [PMID: 24907413 DOI: 10.1016/j.coph.2014.03.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 03/26/2014] [Accepted: 03/27/2014] [Indexed: 01/14/2023]
Abstract
G protein-coupled receptors (GPCRs) utilize (at least) two signal transduction pathways to elicit cellular responses including the classic G protein-dependent, and the more recently discovered β-arrestin-dependent, signaling pathways. In human and murine models of asthma, agonist-activation of β2-adrenergic receptor (β2AR) or Protease-activated-receptor-2 (PAR2) results in relief from bronchospasm via airway smooth muscle relaxation. However, chronic activation of these receptors, leads to pro-inflammatory responses. One plausible explanation underlying the paradoxical effects of β2AR and PAR2 agonism in asthma is that the beneficial and harmful effects are associated with distinct signaling pathways. Specifically, G protein-dependent signaling mediates relaxation of airway smooth muscle, whereas β-arrestin-dependent signaling promotes inflammation. This review explores the evidence supporting the hypothesis that β-arrestin-dependent signaling downstream of β2AR and PAR2 is detrimental in asthma and examines the therapeutic opportunities for selectively targeting this pathway.
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Affiliation(s)
- Julia K L Walker
- Duke University School of Nursing, Duke University Medical Center, Durham, NC 27710, USA.
| | - Katherine A DeFea
- Division of Biomedical Sciences, University of California, Riverside, CA 92521, USA
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55
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Daniele S, Trincavelli ML, Fumagalli M, Zappelli E, Lecca D, Bonfanti E, Campiglia P, Abbracchio MP, Martini C. Does GRK–β arrestin machinery work as a “switch on” for GPR17-mediated activation of intracellular signaling pathways? Cell Signal 2014; 26:1310-25. [DOI: 10.1016/j.cellsig.2014.02.016] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Revised: 02/27/2014] [Accepted: 02/27/2014] [Indexed: 12/13/2022]
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56
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Surve CR, Lehmann D, Smrcka AV. A chemical biology approach demonstrates G protein βγ subunits are sufficient to mediate directional neutrophil chemotaxis. J Biol Chem 2014; 289:17791-801. [PMID: 24808183 DOI: 10.1074/jbc.m114.576827] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Our laboratory has identified a number of small molecules that bind to G protein βγ subunits (Gβγ) by competing for peptide binding to the Gβγ "hot spot." M119/Gallein were identified as inhibitors of Gβγ subunit signaling. Here we examine the activity of another molecule identified in this screen, 12155, which we show that in contrast to M119/Gallein had no effect on Gβγ-mediated phospholipase C or phosphoinositide 3-kinase (PI3K) γ activation in vitro. Also in direct contrast to M119/Gallein, 12155 caused receptor-independent Ca(2+) release, and activated other downstream targets of Gβγ including extracellular signal regulated kinase (ERK), protein kinase B (Akt) in HL60 cells differentiated to neutrophils. We show that 12155 releases Gβγ in vitro from Gαi1β1γ2 heterotrimers by causing its dissociation from GαGDP without inducing nucleotide exchange in the Gα subunit. We used this novel probe to examine the hypothesis that Gβγ release is sufficient to direct chemotaxis of neutrophils in the absence of receptor or G protein α subunit activation. 12155 directed chemotaxis of HL60 cells and primary neutrophils in a transwell migration assay with responses similar to those seen for the natural chemotactic peptide n-formyl-Met-Leu-Phe. These data indicate that release of free Gβγ is sufficient to drive directional chemotaxis in a G protein-coupled receptor signaling-independent manner.
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Affiliation(s)
| | - David Lehmann
- Pharmacology and Physiology, University of Rochester, Rochester, New York 14642
| | - Alan V Smrcka
- From the Departments of Biochemistry and Biophysics and Pharmacology and Physiology, University of Rochester, Rochester, New York 14642
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57
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Yu Y, Zhang M, Zhang X, Cai Q, Hong S, Jiang W, Xu C. Synergistic effects of combined platelet-activating factor receptor and epidermal growth factor receptor targeting in ovarian cancer cells. J Hematol Oncol 2014; 7:39. [PMID: 24886678 PMCID: PMC4028110 DOI: 10.1186/1756-8722-7-39] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Accepted: 04/30/2014] [Indexed: 01/01/2023] Open
Abstract
Background Genetic alterations, including the overexpression of epidermal growth factor receptor (EGFR), play a crucial role in ovarian carcinogenesis. To date, EGFR targeting has shown limited antitumor effects in ovarian cancer when administered as monotherapy. We previously identified platelet-activating factor receptor (PAFR) as being overexpressed in ovarian cancer and found that its ligand PAF evoked EGFR phosphorylation. To determine whether PAFR targeting can enhance the antitumor efficacy of EGFR inhibition, we investigated the effects of a PAFR antagonist (WEB2086) in conjunction with an EGFR inhibitor (AG1478). Methods The expression of EGFR and PAFR in CAOV-3 and SKOV-3 ovarian cancer cell lines was measured by Western blot and immunocytochemistry. Synergy was determined using isobologram analysis. The effects of combined PAFR and EGFR targeting on both cells were assessed by using CCK-8, transwell, flow cytometry, western blot analysis. In vivo studies were conducted using CAOV-3 cells xenografted in nu/nu mice. Results Treatment with combination WEB2086 and AG1478 resulted in significantly greater inhibition of proliferation and invasion compared to either drug alone. When examining equipotent combinations of WEB2086 and AG1478 to determine potential synergy, a combination index (CI) of 0.49 was identified for CAOV-3 cells and a CI of 0.58 for SKOV-3 cells indicating synergy. This co-inhibition induced significantly more apoptosis and arrested the cells at G0/G1 phase in both cell lines. The activation of PAFR and/or EGFR induced phosphorylation of the mTOR, AKT, and MAPK pathways. Combined PAFR and EGFR targeting synergistically diminished the expression of PAFR and EGFR phosphorylation and downstream signaling. In vivo studies further verified the antitumor effects of combined PAFR and EGFR targeting in a CAOV-3 xenograft model. Conclusions These results suggest that WEB2086 and AG1478 are synergistic in ovarian cancer cells with high expression of both PAFR and EGFR. The presented approach may have important therapeutic implications in the treatment of ovarian cancer patients.
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Affiliation(s)
| | | | | | | | | | - Wei Jiang
- Obstetrics and Gynecology Hospital, Fudan University, No,419 Fang-Xie Road, Shanghai, 200011, People's Republic of China.
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58
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Tancevski I, Nairz M, Duwensee K, Auer K, Schroll A, Heim C, Feistritzer C, Hoefer J, Gerner RR, Moschen AR, Heller I, Pallweber P, Li X, Theurl M, Demetz E, Wolf AM, Wolf D, Eller P, Ritsch A, Weiss G. Fibrates ameliorate the course of bacterial sepsis by promoting neutrophil recruitment via CXCR2. EMBO Mol Med 2014; 6:810-20. [PMID: 24755316 PMCID: PMC4203357 DOI: 10.1002/emmm.201303415] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Bacterial sepsis results in high mortality rates, and new therapeutics to control infection are urgently needed. Here, we investigate the therapeutic potential of fibrates in the treatment of bacterial sepsis and examine their effects on innate immunity. Fibrates significantly improved the survival from sepsis in mice infected with Salmonella typhimurium, which was paralleled by markedly increased neutrophil influx to the site of infection resulting in rapid clearance of invading bacteria. As a consequence of fibrate-mediated early control of infection, the systemic inflammatory response was repressed in fibrate-treated mice. Mechanistically, we found that fibrates preserve chemotaxis of murine neutrophils by blocking LPS-induced phosphorylation of ERK. This results in a decrease of G protein-coupled receptor kinase-2 expression, thereby inhibiting the LPS-mediated downregulation of CXCR2, a chemokine receptor critical for neutrophil recruitment. Accordingly, application of a synthetic CXCR2 inhibitor completely abrogated the protective effects of fibrates in septicemia in vivo. Our results unravel a novel function of fibrates in innate immunity and host response to infection and suggest fibrates as a promising adjunct therapy in bacterial sepsis.
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Affiliation(s)
- Ivan Tancevski
- Department of Internal Medicine VI/Infectious Diseases, Immunology, Rheumatology, Pneumology, Innsbruck Medical University, Innsbruck, Austria
| | - Manfred Nairz
- Department of Internal Medicine VI/Infectious Diseases, Immunology, Rheumatology, Pneumology, Innsbruck Medical University, Innsbruck, Austria
| | - Kristina Duwensee
- Department of Internal Medicine VI/Infectious Diseases, Immunology, Rheumatology, Pneumology, Innsbruck Medical University, Innsbruck, Austria
| | - Kristina Auer
- Department of Internal Medicine VI/Infectious Diseases, Immunology, Rheumatology, Pneumology, Innsbruck Medical University, Innsbruck, Austria
| | - Andrea Schroll
- Department of Internal Medicine VI/Infectious Diseases, Immunology, Rheumatology, Pneumology, Innsbruck Medical University, Innsbruck, Austria
| | - Christiane Heim
- Department of Internal Medicine VI/Infectious Diseases, Immunology, Rheumatology, Pneumology, Innsbruck Medical University, Innsbruck, Austria
| | - Clemens Feistritzer
- Department of Internal Medicine VI/Infectious Diseases, Immunology, Rheumatology, Pneumology, Innsbruck Medical University, Innsbruck, Austria
| | - Julia Hoefer
- Department of Urology, Innsbruck Medical University, Innsbruck, Austria
| | - Romana R Gerner
- Department of Internal Medicine I/Gastroenterology, Endocrinology & Metabolism Innsbruck Medical University, Innsbruck, Austria
| | - Alexander R Moschen
- Department of Internal Medicine I/Gastroenterology, Endocrinology & Metabolism Innsbruck Medical University, Innsbruck, Austria
| | - Ingrid Heller
- Department of Hygiene and Medical Microbiology, Innsbruck Medical University, Innsbruck, Austria
| | - Petra Pallweber
- Department of Hygiene and Medical Microbiology, Innsbruck Medical University, Innsbruck, Austria
| | - Xiaorong Li
- Department of Pharmacology, Capital Medical University, Beijing, China
| | - Markus Theurl
- Department of Internal Medicine III/Cardiology, Innsbruck Medical University, Innsbruck, Austria
| | - Egon Demetz
- Department of Internal Medicine VI/Infectious Diseases, Immunology, Rheumatology, Pneumology, Innsbruck Medical University, Innsbruck, Austria
| | - Anna M Wolf
- Department of Hematology/Oncology, University Hospital Bonn, Bonn, Germany
| | - Dominik Wolf
- Department of Hematology/Oncology, University Hospital Bonn, Bonn, Germany
| | - Philipp Eller
- Department of Internal Medicine/Angiology, Medical University of Graz, Graz, Austria
| | - Andreas Ritsch
- Department of Internal Medicine I/Gastroenterology, Endocrinology & Metabolism Innsbruck Medical University, Innsbruck, Austria
| | - Guenter Weiss
- Department of Internal Medicine VI/Infectious Diseases, Immunology, Rheumatology, Pneumology, Innsbruck Medical University, Innsbruck, Austria
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59
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Bias in chemokine receptor signalling. Trends Immunol 2014; 35:243-52. [PMID: 24679437 DOI: 10.1016/j.it.2014.02.004] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 02/12/2014] [Accepted: 02/14/2014] [Indexed: 01/14/2023]
Abstract
Chemokine receptors are widely expressed on a variety of immune cells and play a crucial role in normal physiology as well as in inflammatory and infectious diseases. The existence of 23 chemokine receptors and 48 chemokine ligands guarantees a tight control and fine-tuning of the immune system. Here, we discuss the multiple regulatory mechanisms of chemokine signalling at a systemic, cellular, and molecular level. In particular, we focus on the impact of biased signalling at the receptor level; an emerging concept in molecular pharmacology. An improved understanding of these mechanisms may provide a framework for more effective drug discovery and development at a target class that is so relevant for immune function.
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Taguchi K, Sakata K, Ohashi W, Imaizumi T, Imura J, Hattori Y. Tonic Inhibition by G Protein–Coupled Receptor Kinase 2 of Akt/Endothelial Nitric-Oxide Synthase Signaling in Human Vascular Endothelial Cells under Conditions of Hyperglycemia with High Insulin Levels. J Pharmacol Exp Ther 2014; 349:199-208. [DOI: 10.1124/jpet.113.211854] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
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Singh V, Raghuwanshi SK, Smith N, Rivers EJ, Richardson RM. G Protein-coupled receptor kinase-6 interacts with activator of G protein signaling-3 to regulate CXCR2-mediated cellular functions. THE JOURNAL OF IMMUNOLOGY 2014; 192:2186-94. [PMID: 24510965 DOI: 10.4049/jimmunol.1301875] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The IL-8 (CXCL8) receptors CXCR1 and CXCR2 couple to Gαi to induce leukocyte recruitment and activation at sites of inflammation. We recently showed that CXCR1 couples predominantly to the G protein-coupled receptor kinase (GRK)2, whereas CXCR2 interacts with GRK6 to regulate cellular responses. In addition to G protein-coupled receptors, GRKs displayed a more diverse protein/protein interaction in cells. In this study, we sought to identify GRK6 binding partner(s) that may influence CXCL8 activities, using RBL-2H3 cells stably expressing CXCR1 (RBL-CXCR1) or CXCR2 (RBL-CXCR2), as well as human and murine neutrophils. Our data demonstrated that, upon CXCR2 activation, GRK6 interacts with activator of G protein signaling (AGS)3 and Gαi2 to form a GRK6/AGS3/Gαi2 complex. This complex is time dependent and peaked at 2-3 min postactivation. GTPγS pretreatment blocked GRK6/AGS3/Gαi2 formation, suggesting that this assembly depends on G protein activation. Surprisingly, CXCR2 activation induced AGS3 phosphorylation in a PKC-dependent, but GRK6-independent, fashion. Overexpression of AGS3 in RBL-CXCR2 significantly inhibited CXCL8-induced Ca(2+) mobilization, phosphoinositide hydrolysis, and chemotaxis. In contrast, short hairpin RNA inhibition of AGS3 enhanced CXCL8-induced Ca(2+) mobilization, receptor resistance to desensitization, and recycling to the cell surface, with no effect on receptor internalization. Interestingly, RBL-CXCR2-AGS3(-/-) cells displayed a significant increase in CXCR2 expression on the cell surface but decreased ERK1/2 and P38 MAPK activation. Taken together, these results indicate that GRK6 complexes with AGS3-Gαi2 to regulate CXCR2-mediated leukocyte functions at different levels, including downstream effector activation, receptor trafficking, and expression at the cell membrane.
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Affiliation(s)
- Vandana Singh
- Department of Biology, Julius L. Chambers Biomedical/Biotechnology Research Institute, North Carolina Central University, Durham, NC 27707
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62
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Stevenson NL, Martin-Martin B, Freeman J, Kriston-Vizi J, Ketteler R, Cutler DF. G protein-coupled receptor kinase 2 moderates recruitment of THP-1 cells to the endothelium by limiting histamine-invoked Weibel-Palade body exocytosis. J Thromb Haemost 2014; 12:261-272. [PMID: 24735118 PMCID: PMC4238739 DOI: 10.1111/jth.12470] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 11/21/2013] [Indexed: 01/13/2023]
Abstract
BACKGROUND G protein-coupled receptors (GPCRs) are a major family of signaling molecules, central to the regulation of inflammatory responses. Their activation upon agonist binding is attenuated by GPCR kinases (GRKs), which desensitize the receptors through phosphorylation. G protein-coupled receptor kinase 2(GRK2) down-regulation in leukocytes has been closely linked to the progression of chronic inflammatory disorders such as rheumatoid arthritis and multiple sclerosis. Because leukocytes must interact with the endothelium to infiltrate inflamed tissues, we hypothesized that GRK2 down-regulation in endothelial cells would also be pro-inflammatory. OBJECTIVES To determine whether GRK2 down-regulation in endothelial cells is pro-inflammatory. METHODS siRNA-mediated ablation of GRK2 in human umbilical vein endothelial cells (HUVECs) was used in analyses of the role of this kinase. Microscopic and biochemical analyses of Weibel-Palade body (WPB) formation and functioning, live cell imaging of calcium concentrations and video analyses of adhesion of monocyte-like THP-1 cells provide clear evidence of GRK2 function in histamine activation of endothelial cells. RESULTS G protein-coupled receptor kinase 2 depletion in HUVECs increases WPB exocytosis and P-selectin-dependent adhesion of THP-1 cells to the endothelial surface upon histamine stimulation, relative to controls. Further, live imaging of intracellular calcium concentrations reveals amplified histamine receptor signaling in GRK2-depleted cells, suggesting GRK2 moderates WPB exocytosis through receptor desensitization. CONCLUSIONS G protein-coupled receptor kinase 2 deficiency in endothelial cells results in increased pro-inflammatory signaling and enhanced leukocyte recruitment to activated endothelial cells. The ability of GRK2 to modulate initiation of inflammatory responses in endothelial cells as well as leukocytes now places GRK2 at the apex of control of this finely balanced process.
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Affiliation(s)
- N L Stevenson
- Endothelial Cell Biology Laboratory, MRC Laboratory for Molecular Cell Biology, UCL, London, UK
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63
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Walker AK, Kavelaars A, Heijnen CJ, Dantzer R. Neuroinflammation and comorbidity of pain and depression. Pharmacol Rev 2013; 66:80-101. [PMID: 24335193 DOI: 10.1124/pr.113.008144] [Citation(s) in RCA: 315] [Impact Index Per Article: 28.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Comorbid depression and chronic pain are highly prevalent in individuals suffering from physical illness. Here, we critically examine the possibility that inflammation is the common mediator of this comorbidity, and we explore the implications of this hypothesis. Inflammation signals the brain to induce sickness responses that include increased pain and negative affect. This is a typical and adaptive response to acute inflammation. However, chronic inflammation induces a transition from these typical sickness behaviors into depression and chronic pain. Several mechanisms can account for the high comorbidity of pain and depression that stem from the precipitating inflammation in physically ill patients. These mechanisms include direct effects of cytokines on the neuronal environment or indirect effects via downregulation of G protein-coupled receptor kinase 2, activation of the tryptophan-degrading enzyme indoleamine 2,3-dioxygenase that generates neurotropic kynurenine metabolites, increased brain extracellular glutamate, and the switch of GABAergic neurotransmission from inhibition to excitation. Despite the existence of many neuroimmune candidate mechanisms for the co-occurrence of depression and chronic pain, little work has been devoted so far to critically assess their mediating role in these comorbid symptoms. Understanding neuroimmune mechanisms that underlie depression and pain comorbidity may yield effective pharmaceutical targets that can treat both conditions simultaneously beyond traditional antidepressants and analgesics.
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Affiliation(s)
- A K Walker
- Department of Symptom Research Laboratory of Neuroimmunology of Cancer-Related Symptoms at the Institute of Biosciences and Technology, Texas A&M Health Sciences Center, 2121 W. Holcombe Boulevard, Room 1025, Houston, TX 77030.
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Penela P, Nogués L, Mayor F. Role of G protein-coupled receptor kinases in cell migration. Curr Opin Cell Biol 2013; 27:10-7. [PMID: 24680425 DOI: 10.1016/j.ceb.2013.10.005] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 10/21/2013] [Accepted: 10/23/2013] [Indexed: 01/09/2023]
Abstract
G protein-coupled receptor kinases (GRKs) are emerging as important integrative nodes in cell migration processes. Recent evidence links GRKs (particularly the GRK2 isoform) to the complex modulation of diverse aspects of cell motility. In addition to its well-established role in the desensitization of G protein-coupled receptors involved in chemotaxis, GRK2 can play an effector role in the organization of actin and microtubule networks and in adhesion dynamics, by means of novel substrates and transient interacting partners, such as the GIT1 scaffold or the cytoplasmic α-tubulin deacetylase histone deacetylase 6 (HDAC6). The overall effect of altering GRK levels or activity on chemotaxis would depend on how such different roles are integrated in a given cell type and physiological context, and may have relevant implications in inflammatory diseases or cancer progression.
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Affiliation(s)
- Petronila Penela
- Departamento de Biología Molecular and Centro de Biología Molecular "Severo Ochoa" (Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid), Universidad Autónoma de Madrid, 28049 Madrid, Spain; Instituto de Investigación Sanitaria La Princesa, 28006 Madrid, Spain
| | - Laura Nogués
- Departamento de Biología Molecular and Centro de Biología Molecular "Severo Ochoa" (Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid), Universidad Autónoma de Madrid, 28049 Madrid, Spain; Instituto de Investigación Sanitaria La Princesa, 28006 Madrid, Spain
| | - Federico Mayor
- Departamento de Biología Molecular and Centro de Biología Molecular "Severo Ochoa" (Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid), Universidad Autónoma de Madrid, 28049 Madrid, Spain; Instituto de Investigación Sanitaria La Princesa, 28006 Madrid, Spain.
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65
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Winquist RJ, Mullane K, Williams M. The fall and rise of pharmacology--(re-)defining the discipline? Biochem Pharmacol 2013; 87:4-24. [PMID: 24070656 DOI: 10.1016/j.bcp.2013.09.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2013] [Accepted: 09/09/2013] [Indexed: 12/19/2022]
Abstract
Pharmacology is an integrative discipline that originated from activities, now nearly 7000 years old, to identify therapeutics from natural product sources. Research in the 19th Century that focused on the Law of Mass Action (LMA) demonstrated that compound effects were dose-/concentration-dependent eventually leading to the receptor concept, now a century old, that remains the key to understanding disease causality and drug action. As pharmacology evolved in the 20th Century through successive biochemical, molecular and genomic eras, the precision in understanding receptor function at the molecular level increased and while providing important insights, led to an overtly reductionistic emphasis. This resulted in the generation of data lacking physiological context that ignored the LMA and was not integrated at the tissue/whole organism level. As reductionism became a primary focus in biomedical research, it led to the fall of pharmacology. However, concerns regarding the disconnect between basic research efforts and the approval of new drugs to treat 21st Century disease tsunamis, e.g., neurodegeneration, metabolic syndrome, etc. has led to the reemergence of pharmacology, its rise, often in the semantic guise of systems biology. Against a background of limited training in pharmacology, this has resulted in issues in experimental replication with a bioinformatics emphasis that often has a limited relationship to reality. The integration of newer technologies within a pharmacological context where research is driven by testable hypotheses rather than technology, together with renewed efforts in teaching pharmacology, is anticipated to improve the focus and relevance of biomedical research and lead to novel therapeutics that will contain health care costs.
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Affiliation(s)
- Raymond J Winquist
- Department of Pharmacology, Vertex Pharmaceuticals Inc., Cambridge, MA, United States
| | - Kevin Mullane
- Profectus Pharma Consulting Inc., San Jose, CA, United States
| | - Michael Williams
- Department of Molecular Pharmacology and Biological Chemistry, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States.
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Sorriento D, Fusco A, Ciccarelli M, Rungi A, Anastasio A, Carillo A, Dorn GW, Trimarco B, Iaccarino G. Mitochondrial G protein coupled receptor kinase 2 regulates proinflammatory responses in macrophages. FEBS Lett 2013; 587:3487-94. [PMID: 24036448 DOI: 10.1016/j.febslet.2013.09.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 08/26/2013] [Accepted: 09/02/2013] [Indexed: 01/09/2023]
Abstract
G-protein-coupled receptor kinase 2 (GRK2) levels are elevated in inflammation but its role is not clear yet. Here we show that GRK2 expression is dependent on NFκB transcriptional activity. In macrophages, LPS induces GRK2 accumulation in mitochondria increasing biogenesis. The overexpression of the carboxy-terminal domain of GRK2 (βARK-ct), known to displace GRK2 from plasma membranes, induces earlier localization of GRK2 to mitochondria in response to LPS leading to increased mt-DNA transcription and reduced ROS production and cytokine expression. Our study shows the relevance of GRK2 subcellular localization in macrophage biology and its potential therapeutic properties in inflammation.
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Affiliation(s)
- D Sorriento
- Dipartimento di Scienze Biomediche Avanzate, Università Federico II, Napoli, Italy
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67
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Kim YH, Lee SJ, Seo KW, Bae JU, Park SY, Kim EK, Bae SS, Kim JH, Kim CD. PAF enhances MMP-2 production in rat aortic VSMCs via a β-arrestin2-dependent ERK signaling pathway. J Lipid Res 2013; 54:2678-86. [PMID: 23911909 PMCID: PMC3770081 DOI: 10.1194/jlr.m037176] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Platelet-activating factor (PAF), 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine, is a potent phospholipid mediator and has been reported to be localized in atherosclerotic plaque. However, its role in the progression of atherosclerosis remains unclear. In the present study, we investigated the role of PAF in the production of matrix metalloproteinase (MMP) in primary vascular smooth muscle cells (VSMCs). When rat aortic primary VSMCs were stimulated with PAF (1 nmol/l), the expressions of MMP-2 mRNA and protein, but not of MMP-9, were significantly increased, and these upregulations were markedly attenuated by inhibiting extracellular signal-regulated kinases (ERKs) using molecular and pharmacological inhibitors, but not by using inhibitors of p38 mitogen-activated protein kinase or c-Jun N-terminal kinase. Likewise, ERK phosphorylation was markedly enhanced in PAF-stimulated VSMCs, and this was attenuated by WEB2086, but not by EGF receptor inhibitor, demonstrating the specificity of PAF receptor (PAFR) in PAF-induced ERK phosphorylation. In immunofluorescence studies, β-arrestin2 in PAF-stimulated VSMCs colocalized with PAFR and phosphorylated ERK (P-ERK). Coimmunoprecipitation results suggest that β-arrestin2-bound PAFRs existed as a complex with P-ERK. In addition, PAF-induced ERK phosphorylation and MMP-2 production were significantly attenuated by β-arrestin2 depletion. Taken together, the study shows that PAF enhances MMP-2 production in VSMCs via a β-arrestin2-dependent ERK signaling pathway.
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Affiliation(s)
- Yun H Kim
- Departments of Pharmacology and Pusan National University, Yangsan, Gyeongnam 626-870, Republic of Korea
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68
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Brzostowski JA, Sawai S, Rozov O, Liao XH, Imoto D, Parent CA, Kimmel AR. Phosphorylation of chemoattractant receptors regulates chemotaxis, actin reorganization and signal relay. J Cell Sci 2013; 126:4614-26. [PMID: 23902692 PMCID: PMC3795335 DOI: 10.1242/jcs.122952] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Migratory cells, including mammalian leukocytes and Dictyostelium, use G-protein-coupled receptor (GPCR) signaling to regulate MAPK/ERK, PI3K, TORC2/AKT, adenylyl cyclase and actin polymerization, which collectively direct chemotaxis. Upon ligand binding, mammalian GPCRs are phosphorylated at cytoplasmic residues, uncoupling G-protein pathways, but activating other pathways. However, connections between GPCR phosphorylation and chemotaxis are unclear. In developing Dictyostelium, secreted cAMP serves as a chemoattractant, with extracellular cAMP propagated as oscillating waves to ensure directional migratory signals. cAMP oscillations derive from transient excitatory responses of adenylyl cyclase, which then rapidly adapts. We have studied chemotactic signaling in Dictyostelium that express non-phosphorylatable cAMP receptors and show through chemotaxis modeling, single-cell FRET imaging, pure and chimeric population wavelet quantification, biochemical analyses and TIRF microscopy, that receptor phosphorylation is required to regulate adenylyl cyclase adaptation, long-range oscillatory cAMP wave production and cytoskeletal actin response. Phosphorylation defects thus promote hyperactive actin polymerization at the cell periphery, misdirected pseudopodia and the loss of directional chemotaxis. Our data indicate that chemoattractant receptor phosphorylation is required to co-regulate essential pathways for migratory cell polarization and chemotaxis. Our results significantly extend the understanding of the function of GPCR phosphorylation, providing strong evidence that this evolutionarily conserved mechanism is required in a signal attenuation pathway that is necessary to maintain persistent directional movement of Dictyostelium, neutrophils and other migratory cells.
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Affiliation(s)
- Joseph A Brzostowski
- Laboratory of Immunogenetics Imaging Facility, NIAID/NIH, Rockville, MD 20852, USA
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Vasudevan NT, Mohan ML, Gupta MK, Martelli EE, Hussain AK, Qin Y, Chandrasekharan UM, Young D, Feldman AM, Sen S, Dorn GW, Dicorleto PE, Naga Prasad SV. Gβγ-independent recruitment of G-protein coupled receptor kinase 2 drives tumor necrosis factor α-induced cardiac β-adrenergic receptor dysfunction. Circulation 2013; 128:377-87. [PMID: 23785004 DOI: 10.1161/circulationaha.113.003183] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND Proinflammatory cytokine tumor necrosis factor-α (TNFα) induces β-adrenergic receptor (βAR) desensitization, but mechanisms proximal to the receptor in contributing to cardiac dysfunction are not known. METHODS AND RESULTS Two different proinflammatory transgenic mouse models with cardiac overexpression of myotrophin (a prohypertrophic molecule) or TNFα showed that TNFα alone is sufficient to mediate βAR desensitization as measured by cardiac adenylyl cyclase activity. M-mode echocardiography in these mouse models showed cardiac dysfunction paralleling βAR desensitization independent of sympathetic overdrive. TNFα-mediated βAR desensitization that precedes cardiac dysfunction is associated with selective upregulation of G-protein coupled receptor kinase 2 (GRK2) in both mouse models. In vitro studies in β2AR-overexpressing human embryonic kidney 293 cells showed significant βAR desensitization, GRK2 upregulation, and recruitment to the βAR complex following TNFα. Interestingly, inhibition of phosphoinositide 3-kinase abolished GRK2-mediated βAR phosphorylation and GRK2 recruitment on TNFα. Furthermore, TNFα-mediated βAR phosphorylation was not blocked with βAR antagonist propranolol. Additionally, TNFα administration in transgenic mice with cardiac overexpression of Gβγ-sequestering peptide βARK-ct could not prevent βAR desensitization or cardiac dysfunction showing that GRK2 recruitment to the βAR is Gβγ independent. Small interfering RNA knockdown of GRK2 resulted in the loss of TNFα-mediated βAR phosphorylation. Consistently, cardiomyocytes from mice with cardiac-specific GRK2 ablation normalized the TNFα-mediated loss in contractility, showing that TNFα-induced βAR desensitization is GRK2 dependent. CONCLUSIONS TNFα-induced βAR desensitization is mediated by GRK2 and is independent of Gβγ, uncovering a hitherto unknown cross-talk between TNFα and βAR function, providing the underpinnings of inflammation-mediated cardiac dysfunction.
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Affiliation(s)
- Neelakantan T Vasudevan
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH 44195, USA
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Gene dosage-dependent negative regulatory role of β-arrestin-2 in polymicrobial infection-induced inflammation. Infect Immun 2013; 81:3035-44. [PMID: 23753627 DOI: 10.1128/iai.00653-13] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
β-arrestin-2 (β-arr2) is a scaffolding protein of the arrestin family with a wide variety of cellular functions. Recent studies have demonstrated differential roles for β-arr2 in inflammation following endotoxemia and cecal ligation and puncture (CLP) models of sepsis. Because CLP-induced inflammation involves response to fecal contents and necrotic cecum in addition to microbial challenge, in this study, we examined the role of β-arr2 in an exclusively polymicrobial infection (PMI) model. In addition, we examined the role of gene dosage of β-arr2 in polymicrobial sepsis. Our studies demonstrate that β-arr2 is a negative regulator of systemic inflammation in response to polymicrobial infection and that one allele is sufficient for this process. Our results further reveal that loss of β-arr2 leads to increased neutrophil sequestration and overt inflammation specifically in the lungs following polymicrobial infection. Consistent with this, specific NF-κB and mitogen-activated protein kinase (MAPK) signaling pathways were differentially activated in the β-arr2 knockout (KO) mice lungs compared to the wild type (WT) following PMI. Associated with enhanced inflammation in the KO mice, PMI-induced mortality was also significantly higher in KO mice than in WT mice. To understand the differential role of β-arr2 in different sepsis models, we used cell culture systems to evaluate inflammatory cytokine production following endotoxin and polymicrobial stimulation. Our results demonstrate cell-type- as well as stimulus-specific roles for β-arr2 in inflammation. Taken together, our results reveal a negative regulatory role for β-arr2 in polymicrobial infection-induced inflammation and further demonstrate that one allele of β-arr2 is sufficient to mediate most of these effects.
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71
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Raghuwanshi SK, Smith N, Rivers EJ, Thomas AJ, Sutton N, Hu Y, Mukhopadhyay S, Chen XL, Leung T, Richardson RM. G protein-coupled receptor kinase 6 deficiency promotes angiogenesis, tumor progression, and metastasis. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2013; 190:5329-36. [PMID: 23589623 PMCID: PMC3646980 DOI: 10.4049/jimmunol.1202058] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
G protein-coupled receptor kinases (GRKs) phosphorylate the activated form of G protein-coupled receptors leading to receptor desensitization and downregulation. We have recently shown that the chemokine receptor, CXCR2, couples to GRK6 to regulate cellular responses including chemotaxis, angiogenesis, and wound healing. In this study, we investigate the role of GRK6 in tumorigenesis using murine models of human lung cancer. Mice deficient in GRK6 (GRK6(-/-)) exhibited a significant increase in Lewis lung cancer growth and metastasis relative to control littermates (GRK6(+/+)). GRK6 deletion had no effect on the expression of proangiogenic chemokine or vascular endothelial growth factor, but upregulated matrix metalloproteinase (MMP)-2 and MMP-9 release, tumor-infiltrating PMNs, and microvessel density. Because β-arrestin-2-deficient (βarr2(-/-)) mice exhibited increased Lewis lung cancer growth and metastasis similar to that of GRK6(-/-), we developed a double GRK6(-/-)/βarr2(-/-) mouse model. Surprisingly, GRK6(-/-)/βarr2(-/-) mice exhibited faster tumor growth relative to GRK6(-/-) or βarr2(-/-) mice. Treatment of the mice with anti-CXCR2 Ab inhibited tumor growth in both GRK6(-/-) and GRK6(-/-)/βarr2(-/-) animals. Altogether, the results indicate that CXCR2 couples to GRK6 to regulate angiogenesis, tumor progression, and metastasis. Deletion of GRK6 increases the activity of the host CXCR2, resulting in greater PMN infiltration and MMP release in the tumor microenvironment, thereby promoting angiogenesis and metastasis. Because GRK6(-/-)/βarr2(-/-) showed greater tumor growth relative to GRK6(-/-) or βarr2(-/-) mice, the data further suggest that CXCR2 couples to different mechanisms to mediate tumor progression and metastasis.
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Affiliation(s)
- Sandeep K. Raghuwanshi
- Julius L. Chambers Biomedical/Biotechnology Research Institute and Department of Biology, North Carolina Central University, Durham, NC 27707
| | - Nikia Smith
- Julius L. Chambers Biomedical/Biotechnology Research Institute and Department of Biology, North Carolina Central University, Durham, NC 27707
| | - Elizabeth, J. Rivers
- Julius L. Chambers Biomedical/Biotechnology Research Institute and Department of Biology, North Carolina Central University, Durham, NC 27707
| | - Ariel J. Thomas
- Julius L. Chambers Biomedical/Biotechnology Research Institute and Department of Biology, North Carolina Central University, Durham, NC 27707
| | - Natalie Sutton
- Julius L. Chambers Biomedical/Biotechnology Research Institute and Department of Biology, North Carolina Central University, Durham, NC 27707
| | - Yuhui Hu
- Julius L. Chambers Biomedical/Biotechnology Research Institute and Department of Biology, North Carolina Central University, Durham, NC 27707
| | | | - Xiaoxin L. Chen
- Julius L. Chambers Biomedical/Biotechnology Research Institute and Department of Biology, North Carolina Central University, Durham, NC 27707
| | - TinChung Leung
- Julius L. Chambers Biomedical/Biotechnology Research Institute and Department of Biology, North Carolina Central University, Durham, NC 27707
- North Carolina Research Campus, Nutrition Research Center, 500 Laureate Way, Kannapolis, NC 28081
| | - Ricardo M. Richardson
- Julius L. Chambers Biomedical/Biotechnology Research Institute and Department of Biology, North Carolina Central University, Durham, NC 27707
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Patel J, Channon KM, McNeill E. The downstream regulation of chemokine receptor signalling: implications for atherosclerosis. Mediators Inflamm 2013; 2013:459520. [PMID: 23690662 PMCID: PMC3649756 DOI: 10.1155/2013/459520] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 03/12/2013] [Indexed: 12/13/2022] Open
Abstract
Heterotrimeric G-protein-coupled receptors (GPCRs) are key mediators of intracellular signalling, control numerous physiological processes, and are one of the largest class of proteins to be pharmacologically targeted. Chemokine-induced macrophage recruitment into the vascular wall is an early pathological event in the progression of atherosclerosis. Leukocyte activation and chemotaxis during cell recruitment are mediated by chemokine ligation of multiple GPCRs. Regulation of GPCR signalling is critical in limiting vascular inflammation and involves interaction with downstream proteins such as GPCR kinases (GRKs), arrestin proteins and regulator of G-protein signalling (RGS) proteins. These have emerged as new mediators of atherogenesis by functioning in internalisation, desensitisation, and signal termination of chemokine receptors. Targeting chemokine signalling through these proteins may provide new strategies to alter atherosclerotic plaque formation and plaque biology.
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Affiliation(s)
- Jyoti Patel
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Keith M. Channon
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Eileen McNeill
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
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Link between cancer and Alzheimer disease via oxidative stress induced by nitric oxide-dependent mitochondrial DNA overproliferation and deletion. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2013; 2013:962984. [PMID: 23691268 PMCID: PMC3649749 DOI: 10.1155/2013/962984] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Accepted: 02/01/2013] [Indexed: 01/19/2023]
Abstract
Nitric oxide- (NO-) dependent oxidative stress results in mitochondrial ultrastructural alterations and DNA damage in cases of Alzheimer disease (AD). However, little is known about these pathways in human cancers, especially during the development as well as the progression of primary brain tumors and metastatic colorectal cancer. One of the key features of tumors is the deficiency in tissue energy that accompanies mitochondrial lesions and formation of the hypoxic smaller sized mitochondria with ultrastructural abnormalities. We speculate that mitochondrial involvement may play a significant role in the etiopathogenesis of cancer. Recent studies also demonstrate a potential link between AD and cancer, and anticancer drugs are being explored for the inhibition of AD-like pathology in transgenic mice. Severity of the cancer growth, metastasis, and brain pathology in AD (in animal models that mimic human AD) correlate with the degree of mitochondrial ultrastructural abnormalities. Recent advances in the cell-cycle reentry of the terminally differentiated neuronal cells indicate that NO-dependent mitochondrial abnormal activities and mitotic cell division are not the only important pathogenic factors in pathogenesis of cancer and AD, but open a new window for the development of novel treatment strategies for these devastating diseases.
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Reactivation of desensitized formyl peptide receptors by platelet activating factor: a novel receptor cross talk mechanism regulating neutrophil superoxide anion production. PLoS One 2013; 8:e60169. [PMID: 23555913 PMCID: PMC3610682 DOI: 10.1371/journal.pone.0060169] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 02/22/2013] [Indexed: 11/19/2022] Open
Abstract
Neutrophils express different chemoattractant receptors of importance for guiding the cells from the blood stream to sites of inflammation. These receptors communicate with one another, a cross talk manifested as hierarchical, heterologous receptor desensitization. We describe a new receptor cross talk mechanism, by which desensitized formyl peptide receptors (FPRdes) can be reactivated. FPR desensitization is induced through binding of specific FPR agonists and is reached after a short period of active signaling. The mechanism that transfers the receptor to a non-signaling desensitized state is not known, and a signaling pathway has so far not been described, that transfers FPRdes back to an active signaling state. The reactivation signal was generated by PAF stimulation of its receptor (PAFR) and the cross talk was uni-directional. LatrunculinA, an inhibitor of actin polymerization, induced a similar reactivation of FPRdes as PAF while the phosphatase inhibitor CalyculinA inhibited reactivation, suggesting a role for the actin cytoskeleton in receptor desensitization and reactivation. The activated PAFR could, however, reactivate FPRdes also when the cytoskeleton was disrupted prior to activation. The receptor cross talk model presented prophesies that the contact on the inner leaflet of the plasma membrane that blocks signaling between the G-protein and the FPR is not a point of no return; the receptor cross-talk from the PAFRs to the FPRdes initiates an actin-independent signaling pathway that turns desensitized receptors back to a signaling state. This represents a novel mechanism for amplification of neutrophil production of reactive oxygen species.
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75
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Zhang Q, Coveney AP, Yu S, Liu JH, Li Y, Blankson S, Redmond HP, Wang JH, Wang J. Inefficient antimicrobial functions of innate phagocytes render infant mice more susceptible to bacterial infection. Eur J Immunol 2013; 43:1322-32. [PMID: 23404483 DOI: 10.1002/eji.201243077] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Revised: 01/16/2013] [Accepted: 02/08/2013] [Indexed: 12/16/2022]
Abstract
Neonates and infants, due to the immaturity in their adaptive immunity, are thought to depend largely on the innate immune system for protection against bacterial infection. However, the innate immunity-mediated antimicrobial response in neonates and infants is incompletely characterized. Here, we report that infant mice were more susceptible to microbial sepsis than adult mice, with significantly reduced bacterial clearance from the circulation and visceral organs. Infant PMNs exhibited less constitutive expression of the chemokine receptor CXCR2, and bacterial infection caused further reduction of PMN CXCR2 in infant mice compared with adult mice. This correlates with diminished in vitro chemotaxis of infant PMNs toward the chemoattractant CXCL2 and impaired in vivo recruitment of infant PMNs into the infectious site. Furthermore, consistent with the reduced antimicrobial response in vivo, infant macrophages displayed an impaired bactericidal activity with a defect in phagosome maturation after ingestion of either gram-positive or gram-negative bacteria. Thus, infant mice exhibit an increased vulnerability to microbial infection with delayed bacterial clearance, which is associated with the inefficiency in their innate phagocyte-associated antimicrobial functions characterized by defects in PMN recruitment and macrophage phagosome maturation during microbial sepsis.
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Affiliation(s)
- Qi Zhang
- Department of Pediatric Surgery, Affiliated Children's Hospital, Soochow University, Suzhou, China
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76
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White GE, Iqbal AJ, Greaves DR. CC chemokine receptors and chronic inflammation--therapeutic opportunities and pharmacological challenges. Pharmacol Rev 2013; 65:47-89. [PMID: 23300131 DOI: 10.1124/pr.111.005074] [Citation(s) in RCA: 210] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Chemokines are a family of low molecular weight proteins with an essential role in leukocyte trafficking during both homeostasis and inflammation. The CC class of chemokines consists of at least 28 members (CCL1-28) that signal through 10 known chemokine receptors (CCR1-10). CC chemokine receptors are expressed predominantly by T cells and monocyte-macrophages, cell types associated predominantly with chronic inflammation occurring over weeks or years. Chronic inflammatory diseases including rheumatoid arthritis, atherosclerosis, and metabolic syndrome are characterized by continued leukocyte infiltration into the inflammatory site, driven in large part by excessive chemokine production. Over years or decades, persistent inflammation may lead to loss of tissue architecture and function, causing severe disability or, in the case of atherosclerosis, fatal outcomes such as myocardial infarction or stroke. Despite the existence of several clinical strategies for targeting chronic inflammation, these diseases remain significant causes of morbidity and mortality globally, with a concomitant economic impact. Thus, the development of novel therapeutic agents for the treatment of chronic inflammatory disease continues to be a priority. In this review we introduce CC chemokine receptors as critical mediators of chronic inflammatory responses and explore their potential role as pharmacological targets. We discuss functions of individual CC chemokine receptors based on in vitro pharmacological data as well as transgenic animal studies. Focusing on three key forms of chronic inflammation--rheumatoid arthritis, atherosclerosis, and metabolic syndrome--we describe the pathologic function of CC chemokine receptors and their possible relevance as therapeutic targets.
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Affiliation(s)
- Gemma E White
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
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77
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Moden JI, Haude K, Carroll R, Goodspeed A, Cook LB. Analyzing the role of receptor internalization in the regulation of melanin-concentrating hormone signaling. Int J Endocrinol 2013; 2013:143052. [PMID: 24348551 PMCID: PMC3855962 DOI: 10.1155/2013/143052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 10/10/2013] [Indexed: 11/17/2022] Open
Abstract
The regulation of appetite is complex, though our understanding of the process is improving. The potential role for the melanin-concentrating hormone (MCH) signaling pathway in the treatment of obesity is being explored by many. It was hypothesized that internalization of MCH receptors would act to potently desensitize cells to MCH. Despite potent desensitization of ERK signaling by MCH in BHK-570 cells, we were unable to observe MCH-mediated internalization of MCH receptor 1 (MCHR1) by fluorescence microscopy. A more quantitative approach using a cell-based ELISA indicated only 15% of receptors internalized, which is much lower than that reported in the literature. When β-arrestins were overexpressed in our system, removal of receptors from the cell surface was facilitated and signaling to a leptin promoter was diminished, suggesting that internalization of MCHR1 is sensitive to cellular β-arrestin levels. A dominant-negative GRK construct completely inhibited loss of receptors from the cell surface in response to MCH, suggesting that the internalization observed is phosphorylation-dependent. Since desensitization of MCH-mediated ERK signaling did not correlate with significant loss of MCHR1 from the cell surface, we hypothesize that in this model system regulation of MCH signaling may be the result of segregation of receptors from signaling components at the plasma membrane.
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Affiliation(s)
- Jay I. Moden
- Department of Biology, 217 Lennon Hall, The College at Brockport, State University of New York, 350 New Campus Drive, Brockport, NY 14420, USA
| | - Katrina Haude
- Department of Biology, 217 Lennon Hall, The College at Brockport, State University of New York, 350 New Campus Drive, Brockport, NY 14420, USA
| | - Robert Carroll
- Department of Biology, 217 Lennon Hall, The College at Brockport, State University of New York, 350 New Campus Drive, Brockport, NY 14420, USA
| | - Andrew Goodspeed
- Department of Biology, 217 Lennon Hall, The College at Brockport, State University of New York, 350 New Campus Drive, Brockport, NY 14420, USA
| | - Laurie B. Cook
- Department of Biology, 217 Lennon Hall, The College at Brockport, State University of New York, 350 New Campus Drive, Brockport, NY 14420, USA
- *Laurie B. Cook:
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O'Hayre M, Salanga CL, Handel TM, Hamel DJ. Emerging concepts and approaches for chemokine-receptor drug discovery. Expert Opin Drug Discov 2012; 5:1109-22. [PMID: 21132095 DOI: 10.1517/17460441.2010.525633] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
IMPORTANCE OF THE FIELD Chemokine receptors are most noted for their role in cell migration. However, inappropriate utilization or regulation of these receptors is implicated in many inflammatory diseases, cancer and HIV, making them important drug targets. AREAS COVERED IN THIS REVIEW Allostery, oligomerization and ligand bias are presented as they pertain to chemokine receptors and their associated pathologies.Specific examples of each are described from the recent literature and their implications are discussed in terms of drug discovery efforts targeting chemokine receptors. WHAT THE READER WILL GAIN Insight into the expanding view of the multitude of pharmacological variables that need to be considered or that may be exploited in chemokine receptor drug discovery. TAKE HOME MESSAGE Since 2007, two drugs targeting chemokine receptors have been approved by the FDA, Maraviroc for preventing HIV infection and Mozobil™ for hematopoietic stem cell mobilization. While these successes permit optimism for chemokine receptors as drug targets, only recently has the complexity of this system begun to be appreciated. The concepts of allosteric inhibitors, biased ligands and functional selectivity raise the possibility that drugs with precisely-defined properties can be developed. Other complexities such as receptor oligomerization and tissue-specific functional states of receptors also offer opportunities for increased target and response specificity, although it will be more challenging to translate these ideas into approved therapeutics compared to traditional approaches.
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Affiliation(s)
- Morgan O'Hayre
- University of California, San Diego, Skaggs School of Pharmacy andPharmaceutical Sciences, La Jolla, CA 92093, USA
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Lafarga V, Mayor F, Penela P. The interplay between G protein-coupled receptor kinase 2 (GRK2) and histone deacetylase 6 (HDAC6) at the crossroads of epithelial cell motility. Cell Adh Migr 2012; 6:495-501. [PMID: 23076141 DOI: 10.4161/cam.21585] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
G protein-coupled receptor kinase 2 (GRK2) is emerging as a key integrative node in cell migration control. In addition to its canonical role in the desensitization of G protein-coupled receptors involved in chemotaxis, novel recently identified GRK2 substrates and interacting partners appear to mediate the GRK2-dependent modulation of diverse molecular processes involved in motility, such as gradient sensing, cell polarity or cytoskeletal reorganization. We have recently identified an interaction between GRK2 and histone deacetylase 6 (HDAC6), a major cytoplasmic α-tubulin deacetylase involved in cell motility and adhesion. GRK2 dynamically associates with and phosphorylates HDAC6 to stimulate its α-tubulin deacetylase activity at specific cellular localizations such as the leading edge of migrating cells, thus promoting local tubulin deacetylation and enhanced motility. This GRK2-HDAC6 functional interaction may have important implications in pathological contexts related to aberrant epithelial cell migration.
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Affiliation(s)
- Vanesa Lafarga
- Departamento de Biología Molecular and Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Cientificas, Universidad Autónoma de Madrid, Madrid, Spain
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Raghuwanshi SK, Su Y, Singh V, Haynes K, Richmond A, Richardson RM. The chemokine receptors CXCR1 and CXCR2 couple to distinct G protein-coupled receptor kinases to mediate and regulate leukocyte functions. THE JOURNAL OF IMMUNOLOGY 2012; 189:2824-32. [PMID: 22869904 DOI: 10.4049/jimmunol.1201114] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The chemokine receptors, CXCR1 and CXCR2, couple to Gαi to induce leukocyte recruitment and activation at sites of inflammation. Upon activation by CXCL8, these receptors become phosphorylated, desensitized, and internalized. In this study, we investigated the role of different G protein-coupled receptor kinases (GRKs) in CXCR1- and CXCR2-mediated cellular functions. To that end, short hairpin RNA was used to inhibit GRK2, 3, 5, and 6 in RBL-2H3 cells stably expressing CXCR1 or CXCR2, and CXCL8-mediated receptor activation and regulation were assessed. Inhibition of GRK2 and GRK6 increased CXCR1 and CXCR2 resistance to phosphorylation, desensitization, and internalization, respectively, and enhanced CXCL8-induced phosphoinositide hydrolysis and exocytosis in vitro. GRK2 depletion diminished CXCR1-induced ERK1/2 phosphorylation but had no effect on CXCR2-induced ERK1/2 phosphorylation. GRK6 depletion had no significant effect on CXCR1 function. However, peritoneal neutrophils from mice deficient in GRK6 (GRK6(-/-)) displayed an increase in CXCR2-mediated G protein activation but in vitro exhibited a decrease in chemotaxis, receptor desensitization, and internalization relative to wild-type (GRK6(+/+)) cells. In contrast, neutrophil recruitment in vivo in GRK6(-/-) mice was increased in response to delivery of CXCL1 through the air pouch model. In a wound-closure assay, GRK6(-/-) mice showed enhanced myeloperoxidase activity, suggesting enhanced neutrophil recruitment, and faster wound closure compared with GRK6(+/+) animals. Taken together, the results indicate that CXCR1 and CXCR2 couple to distinct GRK isoforms to mediate and regulate inflammatory responses. CXCR1 predominantly couples to GRK2, whereas CXCR2 interacts with GRK6 to negatively regulate receptor sensitization and trafficking, thus affecting cell signaling and angiogenesis.
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Affiliation(s)
- Sandeep K Raghuwanshi
- Department of Biology, Julius L. Chambers Biomedical/Biotechnology Research Institute, North Carolina Central University, Durham, NC 27707, USA
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81
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Willemen HLDM, Huo XJ, Mao-Ying QL, Zijlstra J, Heijnen CJ, Kavelaars A. MicroRNA-124 as a novel treatment for persistent hyperalgesia. J Neuroinflammation 2012; 9:143. [PMID: 22731384 PMCID: PMC3418202 DOI: 10.1186/1742-2094-9-143] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Accepted: 06/25/2012] [Indexed: 01/12/2023] Open
Abstract
Background Chronic pain is often associated with microglia activation in the spinal cord. We recently showed that microglial levels of the kinase G protein–coupled receptor kinase (GRK)2 are reduced in models of chronic pain. We also found that mice with a cell-specific reduction of around 50% in GRK2 level in microglia/macrophages (LysM-GRK2+/− mice) develop prolonged inflammatory hyperalgesia concomitantly with ongoing spinal microglia/macrophage activation. The microRNA miR-124 is thought to keep microglia/macrophages in brain and spinal cord in a quiescent state. In the present study, we investigated the contribution of miR-124 to regulation of hyperalgesia and microglia/macrophage activation in GRK2-deficient mice. In addition, we investigated the effect of miR-124 on chronic inflammatory and neuropathic pain in wild-type (WT) mice. Methods Hyperalgesia was induced by intraplantar IL-1β in WT and LysM-GRK2+/− mice. We determined spinal cord microglia/macrophage miR-124 expression and levels of pro-inflammatory M1 and anti-inflammatory M2 activation markers. The effect of intrathecal miR-124 treatment on IL-1β-induced hyperalgesia and spinal M1/M2 phenotype, and on carrageenan-induced and spared nerve injury-induced chronic hyperalgesia in WT mice was analyzed. Results Transition from acute to persistent hyperalgesia in LysM-GRK2+/− mice is associated with reduced spinal cord microglia miR-124 levels. In our LysM-GRK2+/− mice, there was a switch towards a pro-inflammatory M1 phenotype together with increased pro-inflammatory cytokine production. Intrathecal administration of miR-124 completely prevented the transition to persistent pain in response to IL-1β in LysM-GRK2+/− mice. The miR-124 treatment also normalized expression of spinal M1/M2 markers of LysM-GRK2+/− mice. Moreover, intrathecal miR-124 treatment reversed the persistent hyperalgesia induced by carrageenan in WT mice and prevented development of mechanical allodynia in the spared nerve injury model of chronic neuropathic pain in WT mice. Conclusions We present the first evidence that intrathecal miR-124 treatment can be used to prevent and treat persistent inflammatory and neuropathic pain. In addition, we show for the first time that persistent hyperalgesia in GRK2-deficient mice is associated with an increased ratio of M1/M2 type markers in spinal cord microglia/macrophages, which is restored by miR-124 treatment. We propose that intrathecal miR-124 treatment might be a powerful novel treatment for pathological chronic pain with persistent microglia activation.
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Affiliation(s)
- Hanneke L D M Willemen
- Laboratory of Neuroimmunology and Developmental Origins of Disease-NIDOD, University Medical Center Utrecht, Utrecht, 3584 EA, The Netherlands
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Kickler K, Maltby K, Ni Choileain S, Stephen J, Wright S, Hafler DA, Jabbour HN, Astier AL. Prostaglandin E2 affects T cell responses through modulation of CD46 expression. THE JOURNAL OF IMMUNOLOGY 2012; 188:5303-10. [PMID: 22544928 DOI: 10.4049/jimmunol.1103090] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The ubiquitous protein CD46, a regulator of complement activity, promotes T cell activation and differentiation toward a regulatory Tr1-like phenotype. The CD46-mediated differentiation pathway is defective in several chronic inflammatory diseases, underlying the importance of CD46 in controlling T cell function and the need to understand its regulatory mechanisms. Using an RNA interference-based screening approach in primary T cells, we have identified that two members of the G protein-coupled receptor kinases were involved in regulating CD46 expression at the surface of activated cells. We have investigated the role of PGE(2), which binds to the E-prostanoid family of G protein-coupled receptors through four subtypes of receptors called EP 1-4, in the regulation of CD46 expression and function. Conflicting roles of PGE(2) in T cell functions have been reported, and the reasons for these apparent discrepancies are not well understood. We show that addition of PGE(2) strongly downregulates CD46 expression in activated T cells. Moreover, PGE(2) differentially affects T cell activation, cytokine production, and phenotype depending on the activation signals received by the T cells. This was correlated with a distinct pattern of the PGE(2) receptors expressed, with EP4 being preferentially induced by CD46 activation. Indeed, addition of an EP4 antagonist could reverse the effects observed on cytokine production after CD46 costimulation. These data demonstrate a novel role of the PGE(2)-EP4 axis in CD46 functions, which might at least partly explain the diverse roles of PGE(2) in T cell functions.
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Affiliation(s)
- Karoline Kickler
- Centre for Inflammation Research, University of Edinburgh, Queen's Medical Research Institute, Edinburgh EH16 4TJ, United Kingdom
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83
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Ishii M, Asano K, Namkoong H, Tasaka S, Mizoguchi K, Asami T, Kamata H, Kimizuka Y, Fujiwara H, Funatsu Y, Kagawa S, Miyata J, Ishii K, Nakamura M, Hirai H, Nagata K, Kunkel SL, Hasegawa N, Betsuyaku T. CRTH2 is a critical regulator of neutrophil migration and resistance to polymicrobial sepsis. THE JOURNAL OF IMMUNOLOGY 2012; 188:5655-64. [PMID: 22544936 DOI: 10.4049/jimmunol.1102330] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Although arachidonic acid cascade has been shown to be involved in sepsis, little is known about the role of PGD(2) and its newly found receptor, chemoattractant receptor-homologous molecule expressed on Th2 cells (CRTH2), on the septic response. Severe sepsis is associated with the failure of neutrophil migration. To investigate whether CRTH2 influences neutrophil recruitment and the lethality during sepsis, sepsis was induced by cecal ligation and puncture (CLP) surgery in mice. CRTH2 knockout (CRTH2(-/-)) mice were highly resistant to CLP-induced sepsis, which was associated with lower bacterial load and lower production of TNF-α, IL-6, and CCL3. IL-10, an anti-inflammatory cytokine, was higher in CRTH2(-/-) mice, blunting CLP-induced lethality in CRTH2(-/-) mice. Neutrophil accumulation in the peritoneum was more pronounced after CLP in CRTH2(-/-) mice, which was associated with higher CXCR2 levels in circulating neutrophils. Furthermore, sepsis caused a decrease in the level of acetylation of histone H3, an activation mark, at the CXCR2 promoter in wild-type neutrophils, suggesting that CXCR2 expression levels are epigenetically regulated. Finally, both pharmacological depletion of neutrophils and inhibition of CXCR2 abrogated the survival benefit in CRTH2(-/-) mice. These results demonstrate that genetic ablation of CRTH2 improved impaired neutrophil migration and survival during severe sepsis, which was mechanistically associated with epigenetic-mediated CXCR2 expression. Thus, CRTH2 is a potential therapeutic target for polymicrobial sepsis.
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Affiliation(s)
- Makoto Ishii
- Division of Pulmonary Medicine, Department of Medicine, Keio University School of Medicine, Tokyo 160-8582, Japan.
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84
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Migration of Th1 lymphocytes is regulated by CD152 (CTLA-4)-mediated signaling via PI3 kinase-dependent Akt activation. PLoS One 2012; 7:e31391. [PMID: 22412835 PMCID: PMC3295805 DOI: 10.1371/journal.pone.0031391] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Accepted: 01/06/2012] [Indexed: 11/20/2022] Open
Abstract
Efficient adaptive immune responses require the localization of T lymphocytes in secondary lymphoid organs and inflamed tissues. To achieve correct localization of T lymphocytes, the migration of these cells is initiated and directed by adhesion molecules and chemokines. It has recently been shown that the inhibitory surface molecule CD152 (CTLA-4) initiates Th cell migration, but the molecular mechanism underlying this effect remains to be elucidated. Using CD4 T lymphocytes derived from OVA-specific TCR transgenic CD152-deficient and CD152-competent mice, we demonstrate that chemokine-triggered signal transduction is differentially regulated by CD152 via phosphoinositide 3-kinase (PI3K)-dependent activation of protein kinase B (PKB/Akt). In the presence of CD152 signaling, the chemoattractant CCL4 selectively induces the full activation of Akt via phosphorylation at threonine 308 and serine 473 in pro-inflammatory Th lymphocytes expressing the cognate chemokine receptor CCR5. Akt signals lead to cytoskeleton rearrangements, which are indispensable for migration. Therefore, this novel Akt-modulating function of CD152 signals affecting T cell migration demonstrates that boosting CD152 or its down-stream signal transduction could aid therapies aimed at sensitizing T lymphocytes for optimal migration, thus contributing to a precise and effective immune response.
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85
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Yanamala N, Gardner E, Riciutti A, Klein-Seetharaman J. The cytoplasmic rhodopsin-protein interface: potential for drug discovery. Curr Drug Targets 2012; 13:3-14. [PMID: 21777183 PMCID: PMC3275648 DOI: 10.2174/138945012798868461] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2010] [Revised: 02/08/2011] [Accepted: 02/10/2011] [Indexed: 01/20/2023]
Abstract
The mammalian dim-light photoreceptor rhodopsin is a prototypic G protein coupled receptor (GPCR), interacting with the G protein, transducin, rhodopsin kinase, and arrestin. All of these proteins interact with rhodopsin at its cytoplasmic surface. Structural and modeling studies have provided in-depth descriptions of the respective interfaces. Overlap and thus competition for binding surfaces is a major regulatory mechanism for signal processing. Recently, it was found that the same surface is also targeted by small molecules. These ligands can directly interfere with the binding and activation of the proteins of the signal transduction cascade, but they can also allosterically modulate the retinal ligand binding pocket. Because the pocket that is targeted contains residues that are highly conserved across Class A GPCRs, these findings imply that it may be possible to target multiple GPCRs with the same ligand(s). This is desirable for example in complex diseases such as cancer where multiple GPCRs participate in the disease networks.
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Affiliation(s)
- Naveena Yanamala
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - Eric Gardner
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - Alec Riciutti
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - Judith Klein-Seetharaman
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
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86
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A novel GRK2/HDAC6 interaction modulates cell spreading and motility. EMBO J 2011; 31:856-69. [PMID: 22193721 DOI: 10.1038/emboj.2011.466] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Accepted: 11/23/2011] [Indexed: 01/08/2023] Open
Abstract
Cell motility and adhesion involves dynamic microtubule (MT) acetylation/deacetylation, a process regulated by enzymes as HDAC6, a major cytoplasmic α-tubulin deacetylase. We identify G protein-coupled receptor kinase 2 (GRK2) as a key novel stimulator of HDAC6. GRK2, which levels inversely correlate with the extent of α-tubulin acetylation in epithelial cells and fibroblasts, directly associates with and phosphorylates HDAC6 to stimulate α-tubulin deacetylase activity. Remarkably, phosphorylation of GRK2 itself at S670 specifically potentiates its ability to regulate HDAC6. GRK2 and HDAC6 colocalize in the lamellipodia of migrating cells, leading to local tubulin deacetylation and enhanced motility. Consistently, cells expressing GRK2-K220R or GRK2-S670A mutants, unable to phosphorylate HDAC6, exhibit highly acetylated cortical MTs and display impaired migration and protrusive activity. Finally, we find that a balanced, GRK2/HDAC6-mediated regulation of tubulin acetylation differentially modulates the early and late stages of cellular spreading. This novel GRK2/HDAC6 functional interaction may have important implications in pathological contexts.
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87
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Yin H, Li X, Yuan B, Zhang B, Hu S, Gu H, Jin X, Zhu J. Heme oxygenase-1 ameliorates LPS-induced acute lung injury correlated with downregulation of interleukin-33. Int Immunopharmacol 2011; 11:2112-7. [DOI: 10.1016/j.intimp.2011.09.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Revised: 09/02/2011] [Accepted: 09/09/2011] [Indexed: 12/09/2022]
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Kim JI, Chakraborty P, Wang Z, Daaka Y. G-protein coupled receptor kinase 5 regulates prostate tumor growth. J Urol 2011; 187:322-9. [PMID: 22099983 DOI: 10.1016/j.juro.2011.09.049] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Indexed: 11/24/2022]
Abstract
PURPOSE The limited success of cancer therapeutics is largely attributable to the ability of cancer to become resistant to conventional cytotoxic chemotherapy. Thus, further identification of signaling molecules and pathways that influence tumorigenesis is needed to increase the overall therapeutic options. GRKs, originally recognized for their conserved role in GPCR signal control, have now emerged as regulators of additional biological molecules and functions. MATERIALS AND METHODS We used Western blot analysis to determine GRK expression in prostate cancer and RNA interference to establish the role of GRK5 in prostate cancer growth and progression through the cell cycle. RESULTS GRK5 was expressed highly in the aggressive prostate cancer PC3 cell line and its silencing by RNA interference attenuated in vitro cell proliferation. PC3 cells that stably expressed lentiviral small hairpin RNA and targeted GRK5 evidence reduced xenograft tumor growth in mice. This was reversed by rescuing expression with wild-type but not with kinase inactive K215R GRK5, implying the need of GRK5 kinase activity for tumor growth. To investigate possible cellular mechanism(s) for GRK5 in cell growth regulation we tested whether kinase activity would impact cell cycle progression. Like forced over expression of kinase-inactive K215R GRK5, GRK5 knockdown led to G2/M arrest in the cell cycle. Also, evidence revealed that the loss of GRK5 activity resulted in decreased cyclin D1 expression, Rb protein phosphorylation and E2F target gene expression involved in cell cycle control. CONCLUSIONS Results provide direct evidence that GRK5 has an immediate role in the regulation of prostate tumor growth.
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Affiliation(s)
- Jae Il Kim
- Department of Urology and Prostate Disease Center, University of Florida College of Medicine, Gainesville, Florida, USA
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Kavelaars A, Eijkelkamp N, Willemen HLDM, Wang H, Carbajal AG, Heijnen CJ. Microglial GRK2: a novel regulator of transition from acute to chronic pain. Brain Behav Immun 2011; 25:1055-60. [PMID: 21473908 DOI: 10.1016/j.bbi.2011.03.019] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Revised: 03/28/2011] [Accepted: 03/30/2011] [Indexed: 12/30/2022] Open
Abstract
Pain is a hallmark of tissue damage and inflammation promoting tissue protection and thereby contributing to repair. Therefore, transient acute pain is an important feature of the adaptive response to damage. However, in a significant number of cases, pain persists for months to years after the problem that originally caused the pain has resolved. Such chronic pain is maladaptive as it no longer serves a protective aim. Chronic pain is debilitating, both physiologically and psychologically, and treatments to provide relief from chronic pain are often ineffective. The neurobiological mechanisms underlying the transition from adaptive acute pain to maladaptive chronic pain are only partially understood. In this review, we will summarize recent evidence that a kinase known as G protein-coupled receptor kinase (GRK2) is a key regulator of the transition from acute to chronic inflammatory pain. Our recent studies have shown that mice with a reduction in the cellular level of GRK2 develop chronic hyperalgesia in response to inflammatory mediators that induce only transient hyperalgesia in WT mice. This finding is clinically relevant because rodent models of chronic pain are associated with reduced cellular levels of GRK2. We propose that GRK2 is a newly discovered major player in the regulation of chronic pain. The pathways regulated by this kinase may open up new avenues for development of treatment strategies that target the cause, and not the symptoms of chronic pain.
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Affiliation(s)
- Annemieke Kavelaars
- Laboratory of Neuroimmunology and Developmental Origins of Disease, University Medical Center Utrecht, Utrecht, The Netherlands.
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Mayor F, Lucas E, Jurado-Pueyo M, Garcia-Guerra L, Nieto-Vazquez I, Vila-Bedmar R, Fernández-Veledo S, Murga C. G Protein-coupled receptor kinase 2 (GRK2): A novel modulator of insulin resistance. Arch Physiol Biochem 2011; 117:125-30. [PMID: 21615207 DOI: 10.3109/13813455.2011.584693] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
G protein-coupled receptor kinase 2 (GRK2) is emerging as a key, integrative node in many signalling pathways. Besides its canonical role in the modulation of the signalling mediated by many G protein-coupled receptors (GPCR), this protein can display a very complex network of functional interactions with a variety of signal transduction partners, in a stimulus, cell type, or context-specific way. We review herein recent data showing that GRK2 can regulate insulin-triggered transduction cascades at different levels and that this protein plays a relevant role in insulin resistance and obesity in vivo, what uncovers GRK2 as a potential therapeutic target in the treatment of these disorders.
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Affiliation(s)
- Federico Mayor
- Departamento de Biología Molecular and Centro de Biología Molecular Severo Ochoa (CSIC-UAM), 28049 Madrid, Spain.
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91
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Wang QT, Zhang LL, Wu HX, Wei W. The expression change of β-arrestins in fibroblast-like synoviocytes from rats with collagen-induced arthritis and the effect of total glucosides of paeony. JOURNAL OF ETHNOPHARMACOLOGY 2011; 133:511-516. [PMID: 20965243 DOI: 10.1016/j.jep.2010.10.022] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2010] [Revised: 10/09/2010] [Accepted: 10/12/2010] [Indexed: 05/30/2023]
Abstract
AIM OF THE STUDY To investigate the expression of β-arrestins in fibroblast-like synoviocytes (FLS) from collagen-induced arthritis (CIA) rats and the effect of total glucosides of paeony (TGP). MATERIALS AND METHODS TGP and glucosides of tripterygium wilfordii (GTW) were intragastriclly administrated to collagen-induced arthritis (CIA) rats after immunization. The secondary inflammatory reaction was evaluated by hind paw swelling, polyarthritis index and histopathological changes. Antibodies to type II collagen (CII) were determined by enzyme-linked immunosorbent assay (ELISA). Synoviocyte proliferations were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl (MTT) assay. The expression of β-arrestins in synoviocytes from CIA rats was measured by western blot. RESULTS The administration of TGP (25, 50, 100 mg/kg) depressed hind paw swelling and decreased the arthritis scores of CIA rats. TGP improved the pathologic manifestations of CIA. Serum anti-CII antibodies level increased significantly in CIA rats, while TGP had no effect on it. Fibroblast-like synoviocytes (FLS) proliferation was inhibited by TGP (50, 100 mg/kg). On d14, d28 after immunization, β-arrestins expression greatly up-regulated in synoviocytes from CIA rats and then returned to baseline levels on d42 after immunization. TGP (50, 100 mg/kg) significantly reduced the expression of β-arrestins. CONCLUSION An inflammatory process in vivo induces an up-regulation of β-arrestins in synoviocytes from CIA rats while TGP can inhibit this change, which might be one of the important mechanisms for TGP to produce a marked therapeutic effect on RA.
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Affiliation(s)
- Qing-Tong Wang
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immunopharmacology of Education Ministry, Meishan Road, Hefei 230032, Anhui Province, China
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Korniejewska A, McKnight AJ, Johnson Z, Watson ML, Ward SG. Expression and agonist responsiveness of CXCR3 variants in human T lymphocytes. Immunology 2011; 132:503-15. [PMID: 21255008 DOI: 10.1111/j.1365-2567.2010.03384.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The chemokine receptor CXCR3 and its ligands CXCL9, CXCL10 and CXCL11 are involved in variety of inflammatory disorders including multiple sclerosis, rheumatoid arthritis, psoriasis and sarcoidosis. Two alternatively spliced variants of the human CXCR3-A receptor have been described, termed CXCR3-B and CXCR3-alt. Human CXCR3-B binds CXCL9, CXCL10, CXCL11 as well as an additional ligand CXCL4. In contrast, CXCR3-alt only binds CXCL11. We report that CXCL4 induces intracellular calcium mobilization as well as Akt and p44/p42 extracellular signal-regulated kinase phosphorylation, in activated human T lymphocytes. These responses have similar concentration dependence and time-courses to those induced by established CXCR3 agonists. Moreover, phosphorylation of Akt and p44/p42 is inhibited by pertussis toxin, suggesting coupling to Gα(i) protein. Surprisingly, and in contrast with the other CXCR3 agonists, stimulation of T lymphocytes with CXCL4 failed to elicit migratory responses and did not lead to loss of surface CXCR3 expression. Taken together, our findings show that, although CXCL4 is coupled to downstream biochemical machinery, its role in T cells is probably distinct from that of CXCR3-A agonists.
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Affiliation(s)
- Anna Korniejewska
- Department of Pharmacy and Pharmacology, University of Bath, Claverton Down, Bath, UK
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de Jager SCA, Bermúdez B, Bot I, Koenen RR, Bot M, Kavelaars A, de Waard V, Heijnen CJ, Muriana FJG, Weber C, van Berkel TJC, Kuiper J, Lee SJ, Abia R, Biessen EAL. Growth differentiation factor 15 deficiency protects against atherosclerosis by attenuating CCR2-mediated macrophage chemotaxis. ACTA ACUST UNITED AC 2011; 208:217-25. [PMID: 21242297 PMCID: PMC3039852 DOI: 10.1084/jem.20100370] [Citation(s) in RCA: 153] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The TGF-β family member GDF-15 promotes lesion formation and plaque instability in atherosclerosis-prone LDLr-deficient mice. Growth differentiation factor (GDF) 15 is a member of the transforming growth factor β (TGF-β) superfamily, which operates in acute phase responses through a currently unknown receptor. Elevated GDF-15 serum levels were recently identified as a risk factor for acute coronary syndromes. We show that GDF-15 expression is up-regulated as disease progresses in murine atherosclerosis and primarily colocalizes with plaque macrophages. Hematopoietic GDF-15 deficiency in low density lipoprotein receptor−/− mice led to impaired initial lesion formation and increased collagen in later lesions. Although lesion burden in GDF-15−/− chimeras was unaltered, plaques had reduced macrophage infiltrates and decreased necrotic core formation, all features of improved plaque stability. In vitro studies pointed to a TGFβRII-dependent regulatory role of GDF-15 in cell death regulation. Importantly, GDF-15−/− macrophages displayed reduced CCR2 expression, whereas GDF-15 promoted macrophage chemotaxis in a strictly CCR2- and TGFβRII-dependent manner, a phenomenon which was not observed in G protein–coupled receptor kinase 2+/− macrophages. In conclusion, GDF-15 deletion has a beneficial effect both in early and later atherosclerosis by inhibition of CCR2-mediated chemotaxis and by modulating cell death. Our study is the first to identify GDF-15 as an acute phase modifier of CCR2/TGFβRII-dependent inflammatory responses to vascular injury.
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Affiliation(s)
- Saskia C A de Jager
- Biopharmaceutics, Leiden/Amsterdam Center for Drug Research, Leiden University, Leiden, Netherlands.
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Inhibition of Guanylyl Cyclase Restores Neutrophil Migration and Maintains Bactericidal Activity Increasing Survival in Sepsis. Shock 2011; 35:17-27. [DOI: 10.1097/shk.0b013e3181e37ea8] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Lysophosphatidylcholines activate G2A inducing G(αi)₋₁-/G(αq/)₁₁- Ca²(+) flux, G(βγ)-Hck activation and clathrin/β-arrestin-1/GRK6 recruitment in PMNs. Biochem J 2010; 432:35-45. [PMID: 20799926 DOI: 10.1042/bj20091087] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Lyso-PCs (lysophosphatidylcholines) are a mixture of lipids that accumulate during storage of cellular blood components, have been implicated in TRALI (transfusion-related acute lung injury) and directly affect the physiology of neutrophils [PMNs (polymorphonuclear leucocytes)]. Because the G2A receptor, expressed on PMNs, has been reported to recognize lyso-PCs, we hypothesize that lyso-PC activation of G2A causes the increases in cytosolic Ca²(+) via release of G(α) and G(βγ) subunits, kinase activation, and the recruitment of clathrin, β-arrestin-1 and GRK6 (G-protein receptor kinase 6) to G2A for signal transduction. PMNs were isolated by standard techniques, primed with lyso-PCs for 5-180 s, and lysed for Western blot analysis, immunoprecipitation or subcellular fractionation, or fixed and smeared on to slides for digital microscopy. The results demonstrated that lyso-PCs cause rapid activation of the G2A receptor through S-phosphorylation and internalization resulting in G(αi)₋₁ and G(αq/)₁₁ release leading to increases in cytosolic Ca²(+), which was inhibited by an antibody to G2A or intracellular neutralization of these subunits. Lyso-PCs also caused the release of the G(βγ) subunit which demonstrated a physical interaction (FRET+) with activated Hck (haemopoietic cell kinase; Tyr⁴¹¹). Moreover, G2A recruited clathrin, β-arrestin-1 and GRK6: clathrin is important for signal transduction, GRK6 for receptor de-sensitization, and β-arrestin-1 both propagates and terminates signals. We conclude that lyso-PC activation of G2A caused release of G(αi)₋₁, G(αq/)₁₁ and G(βγ), resulting in cytosolic Ca²(+) flux, Hck activation, and recruitment of clathrin, β-arrestin-1 and GRK6.
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96
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Nogués L, Salcedo A, Mayor F, Penela P. Multiple scaffolding functions of {beta}-arrestins in the degradation of G protein-coupled receptor kinase 2. J Biol Chem 2010; 286:1165-73. [PMID: 21081496 DOI: 10.1074/jbc.m110.203406] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
G protein-coupled receptor kinase 2 (GRK2) plays a fundamental role in the regulation of G protein-coupled receptors (GPCRs), and changes in GRK2 expression levels can have an important impact on cell functions. GRK2 is known to be degraded by the proteasome pathway. We have shown previously that β-arrestins participate in enhanced kinase turnover upon GPCR stimulation by facilitating GRK2 phosphorylation by c-Src or by MAPK or by recruiting the Mdm2 E3 ubiquitin ligase to the receptor complex. In this report, we have investigated how such diverse β-arrestin scaffold functions are integrated to modulate GRK2 degradation. Interestingly, we found that in the absence of GPCR activation, β-arrestins do not perform an adaptor role for GRK2/Mdm2 association, but rather compete with GRK2 for direct Mdm2 binding to regulate basal kinase turnover. Upon agonist stimulation, β-arrestins-mediated phosphorylation of GRK2 at serine 670 by MAPK facilitates Mdm2-mediated GRK2 degradation, whereas c-Src-dependent phosphorylation would support the action of an undetermined β-arrestin-recruited ligase in the absence of GPCR activation. The ability of β-arrestins to play different scaffold functions would allow coordination of both Mdm2-dependent and -independent processes aimed at the specific modulation of GRK2 turnover in different signaling contexts.
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Affiliation(s)
- Laura Nogués
- Departamento de Biología Molecular and Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, 28049 Madrid, Spain
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97
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Penela P, Murga C, Ribas C, Lafarga V, Mayor F. The complex G protein-coupled receptor kinase 2 (GRK2) interactome unveils new physiopathological targets. Br J Pharmacol 2010; 160:821-32. [PMID: 20590581 DOI: 10.1111/j.1476-5381.2010.00727.x] [Citation(s) in RCA: 167] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
GRK2 is a ubiquitous member of the G protein-coupled receptor kinase (GRK) family that appears to play a central, integrative role in signal transduction cascades. GRKs participate together with arrestins in the regulation of G protein-coupled receptors (GPCR), a family of hundreds of membrane proteins of key physiological and pharmacological importance, by triggering receptor desensitization from G proteins and GPCR internalization, and also by helping assemble macromolecular signalosomes in the receptor environment acting as agonist-regulated adaptor scaffolds, thus contributing to signal propagation. In addition, emerging evidence indicates that GRK2 can phosphorylate a growing number of non-GPCR substrates and associate with a variety of proteins related to signal transduction, thus suggesting that this kinase could also have diverse 'effector' functions. We discuss herein the increasing complexity of such GRK2 'interactome', with emphasis on the recently reported roles of this kinase in cell migration and cell cycle progression and on the functional impact of the altered GRK2 levels observed in several relevant cardiovascular, inflammatory or tumour pathologies. Deciphering how the different networks of potential GRK2 functional interactions are orchestrated in a stimulus, cell type or context-specific way is critical to unveil the contribution of GRK2 to basic cellular processes, to understand how alterations in GRK2 levels or functionality may participate in the onset or development of several cardiovascular, tumour or inflammatory diseases, and to assess the feasibility of new therapeutic strategies based on the modulation of the activity, levels or specific interactions of GRK2.
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Affiliation(s)
- Petronila Penela
- Departamento de Biología Molecular and Centro de Biología Molecular Severo Ochoa (Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid), Universidad Autónoma, Madrid, Spain
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98
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Low nociceptor GRK2 prolongs prostaglandin E2 hyperalgesia via biased cAMP signaling to Epac/Rap1, protein kinase Cepsilon, and MEK/ERK. J Neurosci 2010; 30:12806-15. [PMID: 20861385 DOI: 10.1523/jneurosci.3142-10.2010] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Hyperexcitability of peripheral nociceptive pathways is often associated with inflammation and is an important mechanism underlying inflammatory pain. Here we describe a completely novel mechanism via which nociceptor G-protein-coupled receptor kinase 2 (GRK2) contributes to regulation of inflammatory hyperalgesia. We show that nociceptor GRK2 is downregulated during inflammation. In addition, we show for the first time that prostaglandin E2 (PGE2)-induced hyperalgesia is prolonged from <6 h in wild-type (WT) mice to 3 d in mice with low GRK2 in Nav1.8+ nociceptors (SNS-GRK2+/- mice). This prolongation of PGE2 hyperalgesia in SNS-GRK2+/- mice does not depend on changes in the sensitivity of the prostaglandin receptors because prolonged hyperalgesia also developed in response to 8-Br-cAMP. PGE2 or cAMP-induced hyperalgesia in WT mice is PKA dependent. However, PKA activity is not required for hyperalgesia in SNS-GRK2+/- mice. SNS-GRK2+/- mice developed prolonged hyperalgesia in response to the Exchange proteins directly activated by cAMP (Epac) activator 8-pCPT-2'-O-Me-cAMP (8-pCPT). Coimmunoprecipitation experiments showed that GRK2 binds to Epac1. In vitro, GRK2 deficiency increased 8-pCPT-induced activation of the downstream effector of Epac, Rap1, and extracellular signal-regulated kinase (ERK). In vivo, inhibition of MEK1 or PKCε prevented prolonged PGE2, 8-Br-cAMP, and 8-pCPT hyperalgesia in SNS-GRK2+/- mice. In conclusion, we discovered GRK2 as a novel Epac1-interacting protein. A reduction in the cellular level of GRK2 enhances activation of the Epac-Rap1 pathway. In vivo, low nociceptor GRK2 leads to prolonged inflammatory hyperalgesia via biased cAMP signaling from PKA to Epac-Rap1, ERK/PKCε pathways.
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99
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Garcia-Guerra L, Nieto-Vazquez I, Vila-Bedmar R, Jurado-Pueyo M, Zalba G, Díez J, Murga C, Fernández-Veledo S, Mayor F, Lorenzo M. G protein-coupled receptor kinase 2 plays a relevant role in insulin resistance and obesity. Diabetes 2010; 59:2407-17. [PMID: 20627936 PMCID: PMC3279564 DOI: 10.2337/db10-0771] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
OBJECTIVE Insulin resistance is associated with the pathogenesis of metabolic disorders as type 2 diabetes and obesity. Given the emerging role of signal transduction in these syndromes, we set out to explore the possible role that G protein-coupled receptor kinase 2 (GRK2), first identified as a G protein-coupled receptor regulator, could have as a modulator of insulin responses. RESEARCH DESIGN AND METHODS We analyzed the influence of GRK2 levels in insulin signaling in myoblasts and adipocytes with experimentally increased or silenced levels of GRK2, as well as in GRK2 hemizygous animals expressing 50% lower levels of this kinase in three different models of insulin resistance: tumor necrosis factor-α (TNF-α) infusion, aging, and high-fat diet (HFD). Glucose transport, whole-body glucose and insulin tolerance, the activation status of insulin pathway components, and the circulating levels of important mediators were measured. The development of obesity and adipocyte size with age and HFD was analyzed. RESULTS Altering GRK2 levels markedly modifies insulin-mediated signaling in cultured adipocytes and myocytes. GRK2 levels are increased by ∼2-fold in muscle and adipose tissue in the animal models tested, as well as in lymphocytes from metabolic syndrome patients. In contrast, hemizygous GRK2 mice show enhanced insulin sensitivity and do not develop insulin resistance by TNF-α, aging, or HFD. Furthermore, reduced GRK2 levels induce a lean phenotype and decrease age-related adiposity. CONCLUSIONS Overall, our data identify GRK2 as an important negative regulator of insulin effects, key to the etiopathogenesis of insulin resistance and obesity, which uncovers this protein as a potential therapeutic target in the treatment of these disorders.
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Affiliation(s)
- Lucia Garcia-Guerra
- Department of Biochemistry and Molecular Biology II, Faculty of Pharmacy, Complutense University, Madrid, Spain
- CIBER de Diabetes y Enfermedades Metabólicas (CIBERDEM), Madrid, Spain
| | - Iria Nieto-Vazquez
- Department of Biochemistry and Molecular Biology II, Faculty of Pharmacy, Complutense University, Madrid, Spain
- CIBER de Diabetes y Enfermedades Metabólicas (CIBERDEM), Madrid, Spain
| | - Rocio Vila-Bedmar
- Department of Biochemistry and Molecular Biology II, Faculty of Pharmacy, Complutense University, Madrid, Spain
- CIBER de Diabetes y Enfermedades Metabólicas (CIBERDEM), Madrid, Spain
| | - María Jurado-Pueyo
- Departamento de Biología Molecular and Centro de Biología Molecular Severo Ochoa (CSIC-UAM) and Instituto de Investigación Sanitaria Princesa, Madrid, Spain
| | - Guillermo Zalba
- Division of Cardiovascular Sciences, Center for Applied Medical Research, University of Navarra, Pamplona, Spain
| | - Javier Díez
- Division of Cardiovascular Sciences, Center for Applied Medical Research, University of Navarra, Pamplona, Spain
| | - Cristina Murga
- Departamento de Biología Molecular and Centro de Biología Molecular Severo Ochoa (CSIC-UAM) and Instituto de Investigación Sanitaria Princesa, Madrid, Spain
- Corresponding authors: Cristina Murga, , and Sonia Fernández-Veledo,
| | - Sonia Fernández-Veledo
- Department of Biochemistry and Molecular Biology II, Faculty of Pharmacy, Complutense University, Madrid, Spain
- CIBER de Diabetes y Enfermedades Metabólicas (CIBERDEM), Madrid, Spain
- Corresponding authors: Cristina Murga, , and Sonia Fernández-Veledo,
| | - Federico Mayor
- Departamento de Biología Molecular and Centro de Biología Molecular Severo Ochoa (CSIC-UAM) and Instituto de Investigación Sanitaria Princesa, Madrid, Spain
| | - Margarita Lorenzo
- Department of Biochemistry and Molecular Biology II, Faculty of Pharmacy, Complutense University, Madrid, Spain
- CIBER de Diabetes y Enfermedades Metabólicas (CIBERDEM), Madrid, Spain
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100
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Martin EL, Souza DG, Fagundes CT, Amaral FA, Assenzio B, Puntorieri V, Del Sorbo L, Fanelli V, Bosco M, Delsedime L, Pinho JF, Lemos VS, Souto FO, Alves-Filho JC, Cunha FQ, Slutsky AS, Ruckle T, Hirsch E, Teixeira MM, Ranieri VM. Phosphoinositide-3 Kinase γ Activity Contributes to Sepsis and Organ Damage by Altering Neutrophil Recruitment. Am J Respir Crit Care Med 2010; 182:762-73. [DOI: 10.1164/rccm.201001-0088oc] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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