1
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Tatsumi R, Aihara S, Matsune S, Aoki J, Inoue A, Shimizu T, Nakamura M. Stepwise phosphorylation of BLT1 defines complex assemblies with β-arrestin serving distinct functions. FASEB J 2023; 37:e23213. [PMID: 37795742 DOI: 10.1096/fj.202301440r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2023] [Revised: 09/06/2023] [Accepted: 09/08/2023] [Indexed: 10/06/2023]
Abstract
G protein-coupled receptors (GPCRs) utilize complex cellular systems to respond to diverse ligand concentrations. By taking BLT1, a GPCR for leukotriene B4 (LTB4 ), as a model, our previous work elucidated that this system functions through the modulation of phosphorylation status on two specific residues: Thr308 and Ser310 . Ser310 phosphorylation occurs at a lower LTB4 concentration than Thr308 , leading to a shift in ligand affinity from a high-to-low state. However, the implications of BLT1 phosphorylation in signal transduction processes or the underlying mechanisms have remained unclear. Here, we identify the sequential BLT1-engaged conformations of β-arrestin and subsequent alterations in signal transduction. Stimulation of the high-affinity BLT1 with LTB4 induces phosphorylation at Ser310 via the ERK1/2-GRK pathway, resulting in a β-arrestin-bound low-affinity state. This configuration, referred to as the "low-LTB4 -induced complex," necessitates the finger loop region and the phosphoinositide-binding motif of β-arrestins to interact with BLT1 and deactivates the ERK1/2 signaling. Under high LTB4 concentrations, the low-affinity BLT1 again binds to the ligand and triggers the generation of the low-LTB4 -induced complex into a different form termed "high-LTB4 -induced complex." This change is propelled by The308 -phosphorylation-dependent basal phosphorylation by PKCs. Within the high-LTB4 -induced complex, β-arrestin adapts a unique configuration that involves additional N domain interaction to the low-affinity BLT1 and stimulates the PI3K/AKT pathway. We propose that the stepwise phosphorylation of BLT1 defines the formation of complex assemblies, wherein β-arrestins perform distinct functions.
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Affiliation(s)
- Riko Tatsumi
- Department of Bioscience, Graduate School of Life Science, Okayama University of Science, Okayama, Japan
| | - Saki Aihara
- Department of Bioscience, Graduate School of Life Science, Okayama University of Science, Okayama, Japan
| | - Seiya Matsune
- Department of Bioscience, Graduate School of Life Science, Okayama University of Science, Okayama, Japan
| | - Junken Aoki
- Department of Health Chemistry, Graduate School of Pharmaceutical Science, The University of Tokyo, Tokyo, Japan
- Japan Agency for Medical Research and Development (AMED), Core Research for Evolutional Science and Technology (AMED-CREST), Graduate School of Pharmaceutical Science, University of Tokyo, Tokyo, Japan
| | - Asuka Inoue
- Department of Molecular and Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Takao Shimizu
- Department of Lipid Signaling, National Center for Global Health and Medicine, National Center for Global Health and Medicine, Tokyo, Japan
- Institute of Microbial Chemistry, Tokyo, Japan
| | - Motonao Nakamura
- Department of Bioscience, Graduate School of Life Science, Okayama University of Science, Okayama, Japan
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2
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Lundgren SM, Rocha-Gregg BL, Akdoǧan E, Mysore MN, Hayes S, Collins SR. Signaling dynamics distinguish high- and low-priority neutrophil chemoattractant receptors. Sci Signal 2023; 16:eadd1845. [PMID: 37788324 PMCID: PMC10680494 DOI: 10.1126/scisignal.add1845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 08/23/2023] [Indexed: 10/05/2023]
Abstract
Human neutrophils respond to multiple chemoattractants to guide their migration from the vasculature to sites of infection and injury, where they clear pathogens and amplify inflammation. To properly focus their responses during this complex navigation, neutrophils prioritize pathogen- and injury-derived signals over long-range inflammatory signals, such as the leukotriene LTB4, secreted by host cells. Different chemoattractants can also drive qualitatively different modes of migration even though their receptors couple to the same Gαi family of G proteins. Here, we used live-cell imaging to demonstrate that the responses differed in their signaling dynamics. Low-priority chemoattractants caused transient responses, whereas responses to high-priority chemoattractants were sustained. We observed this difference in both primary neutrophils and differentiated HL-60 cells, for downstream signaling mediated by Ca2+, a major regulator of secretion, and Cdc42, a primary regulator of polarity and cell steering. The rapid attenuation of Cdc42 activation in response to LTB4 depended on the phosphorylation sites Thr308 and Ser310 in the carboxyl-terminal tail of its receptor LTB4R in a manner independent of endocytosis. Mutation of these residues to alanine impaired chemoattractant prioritization, although it did not affect chemoattractant-dependent differences in migration persistence. Our results indicate that distinct temporal regulation of shared signaling pathways distinguishes between receptors and contributes to chemoattractant prioritization.
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Affiliation(s)
- Stefan M. Lundgren
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616, USA
| | - Briana L. Rocha-Gregg
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616, USA
| | - Emel Akdoǧan
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616, USA
| | - Maya N. Mysore
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616, USA
| | - Samantha Hayes
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616, USA
| | - Sean R. Collins
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616, USA
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3
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Yokomizo T, Shimizu T. The leukotriene B 4 receptors BLT1 and BLT2 as potential therapeutic targets. Immunol Rev 2023; 317:30-41. [PMID: 36908237 DOI: 10.1111/imr.13196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2023]
Abstract
Leukotriene B4 (LTB4 ) was recognized as an arachidonate-derived chemotactic factor for inflammatory cells and an important drug target even before the molecular identification of its receptors. We cloned the high- and low-affinity LTB4 receptors, BLT1 and BLT2, respectively, and examined their functions by generating and studying gene-targeted mice. BLT1 is involved in the pathogenesis of various inflammatory and immune diseases, including asthma, psoriasis, contact dermatitis, allergic conjunctivitis, age-related macular degeneration, and immune complex-mediated glomerulonephritis. Meanwhile, BLT2 is a high-affinity receptor for 12-hydroxyheptadecatrienoic acid, which is involved in the maintenance of dermal and intestinal barrier function, and the acceleration of skin and corneal wound healing. Thus, BLT1 antagonists and BLT2 agonists are promising candidates in the treatment of inflammatory diseases.
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Affiliation(s)
- Takehiko Yokomizo
- Department of Biochemistry, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Takao Shimizu
- Institute of Microbial Chemistry, Tokyo, Japan
- Department of Lipid Signaling, National Center for Global Health and Medicine, Tokyo, Japan
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4
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Recent advances in function and structure of two leukotriene B 4 receptors: BLT1 and BLT2. Biochem Pharmacol 2022; 203:115178. [PMID: 35850310 DOI: 10.1016/j.bcp.2022.115178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 07/12/2022] [Accepted: 07/12/2022] [Indexed: 11/21/2022]
Abstract
Leukotriene B4 (LTB4) is generated by the enzymatic oxidation of arachidonic acid, which is then released from the cell membrane and acts as a potent activator of leukocytes and other inflammatory cells. Numerous studies have demonstrated the physiological and pathophysiological significance of this lipid in various diseases. LTB4 exerts its activities by binding to its specific G protein-coupled receptors (GPCRs): BLT1 and BLT2. In mouse disease models, treatment with BLT1 antagonists or BLT1 gene ablation attenuated various diseases, including bronchial asthma, arthritis, and psoriasis, whereas BLT2 deficiency exacerbated several diseases in the skin, cornea, and small intestine. Therefore, BLT1 inhibitors and BLT2 activators could be beneficial for the treatment of several inflammatory and immune disorders. As a result, attractive compounds targeting LTB4 receptors have been developed by several pharmaceutical companies. This review aims to understand the potential of BLT1 and BLT2 as therapeutic targets for the treatment of various inflammatory diseases. In addition, recent topics are discussed with major focuses on the structure and post-translational modifications of BLT1 and BLT2. Collectively, current evidence on modulating LTB4 receptor functions provides new strategies for the treatment of various diseases.
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5
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Kienle K, Glaser KM, Eickhoff S, Mihlan M, Knöpper K, Reátegui E, Epple MW, Gunzer M, Baumeister R, Tarrant TK, Germain RN, Irimia D, Kastenmüller W, Lämmermann T. Neutrophils self-limit swarming to contain bacterial growth in vivo. Science 2021; 372:372/6548/eabe7729. [PMID: 34140358 DOI: 10.1126/science.abe7729] [Citation(s) in RCA: 74] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Accepted: 04/29/2021] [Indexed: 12/30/2022]
Abstract
Neutrophils communicate with each other to form swarms in infected organs. Coordination of this population response is critical for the elimination of bacteria and fungi. Using transgenic mice, we found that neutrophils have evolved an intrinsic mechanism to self-limit swarming and avoid uncontrolled aggregation during inflammation. G protein-coupled receptor (GPCR) desensitization acts as a negative feedback control to stop migration of neutrophils when they sense high concentrations of self-secreted attractants that initially amplify swarming. Interference with this process allows neutrophils to scan larger tissue areas for microbes. Unexpectedly, this does not benefit bacterial clearance as containment of proliferating bacteria by neutrophil clusters becomes impeded. Our data reveal how autosignaling stops self-organized swarming behavior and how the finely tuned balance of neutrophil chemotaxis and arrest counteracts bacterial escape.
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Affiliation(s)
- Korbinian Kienle
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany.,International Max Planck Research School for Immunobiology, Epigenetics and Metabolism (IMPRS-IEM), Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Katharina M Glaser
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany.,International Max Planck Research School for Immunobiology, Epigenetics and Metabolism (IMPRS-IEM), Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Sarah Eickhoff
- Institute of Systems Immunology, University of Würzburg, Max Planck Research Group, Würzburg, Germany
| | - Michael Mihlan
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Konrad Knöpper
- Institute of Systems Immunology, University of Würzburg, Max Planck Research Group, Würzburg, Germany
| | - Eduardo Reátegui
- Center for Engineering in Medicine, Massachusetts General Hospital, Harvard Medical School, Shriners Hospital for Children, Boston, MA, USA.,William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH, USA
| | - Maximilian W Epple
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany.,International Max Planck Research School for Immunobiology, Epigenetics and Metabolism (IMPRS-IEM), Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Matthias Gunzer
- Institute for Experimental Immunology and Imaging, University Hospital, University Duisburg-Essen, Essen, Germany.,Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V., Dortmund, Germany
| | - Ralf Baumeister
- Bioinformatics and Molecular Genetics, Faculty of Biology, Centre for Biochemistry and Molecular Cell Research, Faculty of Medicine, Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Teresa K Tarrant
- Division of Rheumatology and Immunology, Department of Medicine, Duke University School of Medicine, Durham, NC, USA
| | - Ronald N Germain
- Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA
| | - Daniel Irimia
- Center for Engineering in Medicine, Massachusetts General Hospital, Harvard Medical School, Shriners Hospital for Children, Boston, MA, USA
| | - Wolfgang Kastenmüller
- Institute of Systems Immunology, University of Würzburg, Max Planck Research Group, Würzburg, Germany
| | - Tim Lämmermann
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany.
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6
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Biringer RG. A review of non-prostanoid, eicosanoid receptors: expression, characterization, regulation, and mechanism of action. J Cell Commun Signal 2021; 16:5-46. [PMID: 34173964 DOI: 10.1007/s12079-021-00630-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 06/07/2021] [Indexed: 11/29/2022] Open
Abstract
Eicosanoid signaling controls a wide range of biological processes from blood pressure homeostasis to inflammation and resolution thereof to the perception of pain and to cell survival itself. Disruption of normal eicosanoid signaling is implicated in numerous disease states. Eicosanoid signaling is facilitated by G-protein-coupled, eicosanoid-specific receptors and the array of associated G-proteins. This review focuses on the expression, characterization, regulation, and mechanism of action of non-prostanoid, eicosanoid receptors.
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Affiliation(s)
- Roger G Biringer
- College of Osteopathic Medicine, Lake Erie College of Osteopathic Medicine, 5000 Lakewood Ranch Blvd, Bradenton, FL, 34211, USA.
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7
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Fletcher-Jones A, Hildick KL, Evans AJ, Nakamura Y, Henley JM, Wilkinson KA. Protein Interactors and Trafficking Pathways That Regulate the Cannabinoid Type 1 Receptor (CB1R). Front Mol Neurosci 2020; 13:108. [PMID: 32595453 PMCID: PMC7304349 DOI: 10.3389/fnmol.2020.00108] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 05/20/2020] [Indexed: 12/29/2022] Open
Abstract
The endocannabinoid system (ECS) acts as a negative feedback mechanism to suppress synaptic transmission and plays a major role in a diverse range of brain functions including, for example, the regulation of mood, energy balance, and learning and memory. The function and dysfunction of the ECS are strongly implicated in multiple psychiatric, neurological, and neurodegenerative diseases. Cannabinoid type 1 receptor (CB1R) is the most abundant G protein-coupled receptor (GPCR) expressed in the brain and, as for any synaptic receptor, CB1R needs to be in the right place at the right time to respond appropriately to changing synaptic circumstances. While CB1R is found intracellularly throughout neurons, its surface expression is highly polarized to the axonal membrane, consistent with its functional expression at presynaptic sites. Surprisingly, despite the importance of CB1R, the interacting proteins and molecular mechanisms that regulate the highly polarized distribution and function of CB1R remain relatively poorly understood. Here we set out what is currently known about the trafficking pathways and protein interactions that underpin the surface expression and axonal polarity of CB1R, and highlight key questions that still need to be addressed.
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Affiliation(s)
- Alexandra Fletcher-Jones
- Centre for Synaptic Plasticity, School of Biochemistry, University of Bristol, Bristol, United Kingdom
| | - Keri L Hildick
- Centre for Synaptic Plasticity, School of Biochemistry, University of Bristol, Bristol, United Kingdom
| | - Ashley J Evans
- Centre for Synaptic Plasticity, School of Biochemistry, University of Bristol, Bristol, United Kingdom
| | - Yasuko Nakamura
- Centre for Synaptic Plasticity, School of Biochemistry, University of Bristol, Bristol, United Kingdom
| | - Jeremy M Henley
- Centre for Synaptic Plasticity, School of Biochemistry, University of Bristol, Bristol, United Kingdom
| | - Kevin A Wilkinson
- Centre for Synaptic Plasticity, School of Biochemistry, University of Bristol, Bristol, United Kingdom
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8
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Pandey A, LeBlanc DM, Parmar HB, Phạm TTT, Sarker M, Xu L, Duncan R, Liu XQ, Rainey JK. Structure, amphipathy, and topology of the membrane-proximal helix 8 influence apelin receptor plasma membrane localization. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:183036. [PMID: 31394100 DOI: 10.1016/j.bbamem.2019.183036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 07/08/2019] [Accepted: 08/02/2019] [Indexed: 12/11/2022]
Abstract
G-protein coupled receptors (GPCRs) typically have an amphipathic helix ("helix 8") immediately C-terminal to the transmembrane helical bundle. To date, a number of functional roles have been associated with GPCR helix 8 segments, but structure-function analysis for this region remains limited. Here, we examine helix 8 of the apelin receptor (AR or APJ), a class A GPCR with wide physiological and pathophysiological relevance. The 71 residue C-terminal tail of the AR is primarily intrinsically disordered, with a detergent micelle-induced increase in helical character. This helicity was localized to the helix 8 region, in good agreement with the recent AR crystal structure. A series of helix 8 mutants were made to reduce helicity, remove amphipathy, or flip the hydrophobic and hydrophilic faces. Each mutant AR was tested both biophysically, in the isolated C-terminal tail, and functionally in HEK 293 T cells, for full-length AR. In all instances, micelle interactions were maintained, and steady-state AR expression was efficient. However, removal of amphipathy or helical character led to a significant decrease in cell surface localization. Flipping of helix 8 amphipathic topology restored cell surface localization to some degree, but still was significantly reduced relative to wild-type. Structural integrity, amphipathy to drive membrane association, and correct topology of helix 8 membrane association all thus appear important for cell surface localization of the AR. This behavior correlates well to GPCR C-terminal tail sequence motifs, implying that these serve to specify key topological features of helix 8 and its proximity to the transmembrane domain.
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Affiliation(s)
- Aditya Pandey
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Danielle M LeBlanc
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Hirendrasinh B Parmar
- Department of Microbiology & Immunology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Trần Thanh Tâm Phạm
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Muzaddid Sarker
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada; Department of Microbiology & Immunology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Lingling Xu
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Roy Duncan
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada; Department of Microbiology & Immunology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Xiang-Qin Liu
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Jan K Rainey
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada; Department of Chemistry, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada.
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9
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Arginine 313 of the putative 8th helix mediates Gα q/14 coupling of human CC chemokine receptors CCR2a and CCR2b. Cell Signal 2018; 53:170-183. [PMID: 30321592 DOI: 10.1016/j.cellsig.2018.10.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 10/08/2018] [Accepted: 10/10/2018] [Indexed: 01/29/2023]
Abstract
In man, two CC chemokine receptor isoforms, CCR2a and CCR2b, are present that belong to the rhodopsin-like G protein-coupled receptor family, and couple to Gi and Gq family members. The CCR2 receptors are known to regulate canonical functions of chemokines such as directed migration of leukocytes, and to potentially control non-canonical functions such as differentiation, proliferation, and gene transcription of immune and non-immune cells. We recently reported on the activation of phospholipase C isoenzymes and RhoA GTPases by coupling of the two CCR2 receptors to members of the Gq family, in particular Gαq and Gα14. So far little is known about the structural requirements for the CCR2/Gq/14 interaction. Interestingly, the CCR2 receptor isoforms are identical up to arginine 313 (R313) that is part of the putative 8th helix in CCR2 receptors, and the 8th helix has been implicated in the interaction of rhodopsin-like G protein-coupled receptors with Gαq. In the present work we describe that the 8th helix of both CCR2a and CCR2b is critically involved in selectively activating Gαq/14-regulated signaling. Refined analysis using various CCR2a and CCR2b mutants and analyzing their cellular signaling, e.g. ligand-dependent (i) activation of phospholipase C isoenzymes, (ii) stimulation of serum response factor-mediated gene transcription, (iii) activation of mitogen-activated protein kinases, (iv) internalization, and (v) changes in intracellular calcium concentrations, identified arginine 313 within the amino terminal portion of helix 8 to play a role for the agonist-mediated conformational changes and the formation of a Gαq/14 binding surface. We show that R313 determines Gαq/14 protein-dependent but not Gi protein-dependent cellular signaling, and plays no role in Gq/Gi-independent receptor internalization, indicating a role of R313 in biased signaling of CCR2 receptors.
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10
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Subramanian BC, Moissoglu K, Parent CA. The LTB 4-BLT1 axis regulates the polarized trafficking of chemoattractant GPCRs during neutrophil chemotaxis. J Cell Sci 2018; 131:jcs.217422. [PMID: 30158177 DOI: 10.1242/jcs.217422] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 08/20/2018] [Indexed: 01/14/2023] Open
Abstract
Neutrophils sense and respond to diverse chemotactic cues through G-protein-coupled receptors (GPCRs). However, the precise trafficking dynamics of chemoattractant GPCRs during neutrophil activation and chemotaxis remain unclear. Here, by using small-molecule inhibitors and CRISPR-based knockouts, we establish that two primary chemoattractant GPCRs - formyl peptide receptor 1 (FPR1) and complement component 5a (C5a) receptor 1 (C5aR1) - internalize in a CDC42-actin-dependent manner. Through live-cell imaging, we demonstrate that, upon stimulation, FPR1 rapidly clusters and re-distributes along the plasma membrane to the trailing edge, where it internalizes and is directionally trafficked towards the front of migrating primary human neutrophils. In contrast to FPR1 and C5aR1, the leukotriene B4 (LTB4) receptor (BLT1, also known as LTB4R), which relays LTB4 signals in response to primary chemoattractants during neutrophil chemotaxis, fails to internalize upon physiological stimulation with LTB4, N-formyl-Met-Leu-Phe (fMLF) or C5a. Importantly, we report that blocking the LTB4-BLT1 axis or downstream myosin activation enhances the internalization of FPR1 and C5aR1, thus reducing downstream signaling and impairing chemotaxis to primary chemoattractants. The polarized trafficking of chemoattractant GPCRs and its regulation by the BLT1-mediated myosin activation therefore drives persistent chemotactic signaling in neutrophils.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Bhagawat C Subramanian
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Konstadinos Moissoglu
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Carole A Parent
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA .,Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, USA
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11
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Nakanishi Y, Tan M, Ichiki T, Inoue A, Yoshihara JI, Maekawa N, Takenoshita I, Yanagida K, Yamahira S, Yamaguchi S, Aoki J, Nagamune T, Yokomizo T, Shimizu T, Nakamura M. Stepwise phosphorylation of leukotriene B 4 receptor 1 defines cellular responses to leukotriene B 4. Sci Signal 2018; 11:11/544/eaao5390. [PMID: 30131369 DOI: 10.1126/scisignal.aao5390] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Leukotriene B4 (LTB4) receptor type 1 (BLT1) is abundant in phagocytic and immune cells and plays crucial roles in various inflammatory diseases. BLT1 is phosphorylated at several serine and threonine residues upon stimulation with the inflammatory lipid LTB4 Using Phos-tag gel electrophoresis to separate differentially phosphorylated forms of BLT1, we identified two distinct types of phosphorylation, basal and ligand-induced, in the carboxyl terminus of human BLT1. In the absence of LTB4, the basal phosphorylation sites were modified to various degrees, giving rise to many different phosphorylated forms of BLT1. Different concentrations of LTB4 induced distinct phosphorylation events, and these ligand-induced modifications facilitated additional phosphorylation events at the basal phosphorylation sites. Because neutrophils migrate toward inflammatory sites along a gradient of LTB4, the degree of BLT1 phosphorylation likely increases in parallel with the increase in LTB4 concentration as the cells migrate. At high concentrations of LTB4, deficiencies in these two types of phosphorylation events impaired chemotaxis and β-hexosaminidase release, a proxy for degranulation, in Chinese hamster ovary (CHO-K1) and rat basophilic leukemia (RBL-2H3) cells, respectively. These results suggest that an LTB4 gradient around inflammatory sites enhances BLT1 phosphorylation in a stepwise manner to facilitate the precise migration of phagocytic and immune cells and the initiation of local responses, including degranulation.
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Affiliation(s)
- Yoshimitsu Nakanishi
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Modong Tan
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Takako Ichiki
- Department of Biochemistry, Juntendo University School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Asuka Inoue
- Department of Molecular and Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Jun-Ichi Yoshihara
- Department of Life Science, Faculty of Science, Okayama University of Science, 1-1 Ridai-cho, Kita-ku, Okayama 700-0005, Japan
| | - Naoto Maekawa
- Department of Life Science, Faculty of Science, Okayama University of Science, 1-1 Ridai-cho, Kita-ku, Okayama 700-0005, Japan
| | - Itsuki Takenoshita
- Department of Life Science, Faculty of Science, Okayama University of Science, 1-1 Ridai-cho, Kita-ku, Okayama 700-0005, Japan
| | - Keisuke Yanagida
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Shinya Yamahira
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Satoshi Yamaguchi
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Junken Aoki
- Department of Molecular and Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan.,Japan Agency for Medical Research and Development (AMED), Core Research for Evolutional Science and Technology (CREST), 1-7-1 Otemachi, Chiyoda-ku, Tokyo 100-0004, Japan
| | - Teruyuki Nagamune
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Takehiko Yokomizo
- Department of Biochemistry, Juntendo University School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Takao Shimizu
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.,Department of Lipid Signaling, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku-ku, Tokyo 162-8655, Japan
| | - Motonao Nakamura
- Department of Life Science, Faculty of Science, Okayama University of Science, 1-1 Ridai-cho, Kita-ku, Okayama 700-0005, Japan.
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12
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Saeki K, Yokomizo T. Identification, signaling, and functions of LTB 4 receptors. Semin Immunol 2018; 33:30-36. [PMID: 29042026 DOI: 10.1016/j.smim.2017.07.010] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 05/02/2017] [Accepted: 07/26/2017] [Indexed: 10/18/2022]
Abstract
Leukotriene B4 (LTB4), a lipid mediator produced from arachidonic acid, is a chemoattractant for inflammatory leukocytes. We identified two receptors for LTB4, the high-affinity receptor BLT1 and the low-affinity receptor BLT2. BLT1 is expressed in various subsets of leukocytes, and analyses of BLT1-deficient mice revealed that the LTB4/BLT1 axis enhances leukocyte recruitment to infected sites, and is involved in the elimination of pathogens. Hyperactivation of the LTB4/BLT1 axis induces acute and chronic inflammation, resulting in various inflammatory diseases. BLT2 was originally identified as a low-affinity receptor for LTB4, and we later identified 12(S)-hydroxy-5Z,8E,10E-heptadecatrienoic acid (12-HHT) as a high-affinity ligand for BLT2. BLT2 is highly expressed in epithelial cells in various tissues including intestine and skin. Large quantities of 12-HHT are produced by activated platelets during skin injury, and activation of BLT2 on epidermal keratinocytes accelerates skin wound healing by enhancing cell migration. BLT2 signaling also enhances cell-cell junctions, protectes against transepidermal water loss, and preventes entry of environmental substances into the body.
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Affiliation(s)
- Kazuko Saeki
- Department of Biochemistry, Juntendo University School of Medicine, Tokyo, Japan
| | - Takehiko Yokomizo
- Department of Biochemistry, Juntendo University School of Medicine, Tokyo, Japan.
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13
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Subramanian BC, Majumdar R, Parent CA. The role of the LTB 4-BLT1 axis in chemotactic gradient sensing and directed leukocyte migration. Semin Immunol 2018; 33:16-29. [PMID: 29042024 DOI: 10.1016/j.smim.2017.07.002] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 06/07/2017] [Accepted: 07/13/2017] [Indexed: 12/11/2022]
Abstract
Directed leukocyte migration is a hallmark of inflammatory immune responses. Leukotrienes are derived from arachidonic acid and represent a class of potent lipid mediators of leukocyte migration. In this review, we summarize the essential steps leading to the production of LTB4 in leukocytes. We discuss the recent findings on the exosomal packaging and transport of LTB4 in the context of chemotactic gradients formation and regulation of leukocyte recruitment. We also discuss the dynamic roles of the LTB4 receptors, BLT1 and BLT2, in mediating chemotactic signaling in leukocytes and contrast them to other structurally related leukotrienes that bind to distinct GPCRs. Finally, we highlight the specific roles of the LTB4-BLT1 axis in mediating signal-relay between chemotaxing neutrophils and its potential contribution to a wide variety of inflammatory conditions including tumor progression and metastasis, where LTB4 is emerging as a key signaling component.
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Affiliation(s)
- Bhagawat C Subramanian
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, NCI, NIH, Bethesda, MD 20892, United States.
| | - Ritankar Majumdar
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, NCI, NIH, Bethesda, MD 20892, United States; Department of Pharmacology, University of Michigan School of Medicine, Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, United States.
| | - Carole A Parent
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, NCI, NIH, Bethesda, MD 20892, United States; Department of Pharmacology, University of Michigan School of Medicine, Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, United States.
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14
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Yokomizo T, Nakamura M, Shimizu T. Leukotriene receptors as potential therapeutic targets. J Clin Invest 2018; 128:2691-2701. [PMID: 29757196 DOI: 10.1172/jci97946] [Citation(s) in RCA: 106] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Leukotrienes, a class of arachidonic acid-derived bioactive molecules, are known as mediators of allergic and inflammatory reactions and considered to be important drug targets. Although an inhibitor of leukotriene biosynthesis and antagonists of the cysteinyl leukotriene receptor are clinically used for bronchial asthma and allergic rhinitis, these medications were developed before the molecular identification of leukotriene receptors. Numerous studies using cloned leukotriene receptors and genetically engineered mice have unveiled new pathophysiological roles for leukotrienes. This Review covers the recent findings on leukotriene receptors to revisit them as new drug targets.
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Affiliation(s)
- Takehiko Yokomizo
- Department of Biochemistry, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Motonao Nakamura
- Department of Life Science, Graduate School of Science, Okayama University of Science, Okayama, Japan
| | - Takao Shimizu
- Department of Lipidomics, Faculty of Medicine, University of Tokyo, Tokyo, Japan.,Department of Lipid Signaling, National Center for Global Health and Medicine, Tokyo, Japan
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15
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Fridmanis D, Roga A, Klovins J. ACTH Receptor (MC2R) Specificity: What Do We Know About Underlying Molecular Mechanisms? Front Endocrinol (Lausanne) 2017; 8:13. [PMID: 28220105 PMCID: PMC5292628 DOI: 10.3389/fendo.2017.00013] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 01/16/2017] [Indexed: 11/13/2022] Open
Abstract
Coincidentally, the release of this Research Topic in Frontiers in Endocrinology takes place 25 years after the discovery of the adrenocorticotropic hormone receptor (ACTHR) by Mountjoy and colleagues. In subsequent years, following the discovery of other types of mammalian melanocortin receptors (MCRs), ACTHR also became known as melanocortin type 2 receptor (MC2R). At present, five types of MCRs have been reported, all of which share significant sequence similarity at the amino acid level, and all of which specifically bind melanocortins (MCs)-a group of biologically active peptides generated by proteolysis of the proopiomelanocortin precursor. All MCs share an identical -H-F-R-W- pharmacophore sequence. α-Melanocyte-stimulating hormone (α-MSH) and adrenocorticotropic hormone (ACTH) are the most extensively studied MCs and are derived from the same region. Essentially, α-MSH is formed from the first 13 amino acid residues of ACTH. ACTHR is unique among MCRs because it binds one sole ligand-ACTH, which makes it a very attractive research object for molecular pharmacologists. However, much research has failed, and functional studies of this receptor are lagging behind other MCRs. The reason for these difficulties has already been outlined by Mountjoy and colleagues in their publication on ACTHR coding sequence discovery where the Cloudman S91 melanoma cell line was used for receptor expression because it was a "more sensitive assay system." Subsequent work showed that ACTHR could be successfully expressed only in endogenous MCR-expressing cell lines, since in other cell lines it is retained within the endoplasmic reticulum. The resolution of this methodological problem came in 2005 with the discovery of melanocortin receptor accessory protein, which is required for the formation of functionally active ACTHR. The decade that followed this discovery was filled with exciting research that provided insight into the molecular mechanisms underlying the action of ACTHR. The purpose of this review is to summarize the advances in this fascinating research field.
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Affiliation(s)
| | - Ance Roga
- Latvian Biomedical Research and Study Centre, Riga, Latvia
| | - Janis Klovins
- Latvian Biomedical Research and Study Centre, Riga, Latvia
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Karpinsky-Semper D, Tayou J, Levay K, Schuchardt BJ, Bhat V, Volmar CH, Farooq A, Slepak VZ. Helix 8 and the i3 loop of the muscarinic M3 receptor are crucial sites for its regulation by the Gβ5-RGS7 complex. Biochemistry 2015; 54:1077-88. [PMID: 25551629 PMCID: PMC4318586 DOI: 10.1021/bi500980d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
![]()
The muscarinic M3 receptor (M3R)
is a Gq-coupled receptor and is
known to interact with many intracellular regulatory proteins. One
of these molecules is Gβ5-RGS7, the permanently associated heterodimer
of G protein β-subunit Gβ5 and RGS7, a regulator of G
protein signaling. Gβ5-RGS7 can attenuate M3R-stimulated release
of Ca2+ from intracellular stores or enhance the influx
of Ca2+ across the plasma membrane. Here we show that deletion
of amino acids 304–345 from the central portion of the i3 loop
renders M3R insensitive to regulation by Gβ5-RGS7. In addition
to the i3 loop, interaction of M3R with Gβ5-RGS7 requires helix
8. According to circular dichroism spectroscopy, the peptide corresponding
to amino acids 548–567 in the C-terminus of M3R assumes an
α-helical conformation. Substitution of Thr553 and Leu558 with
Pro residues disrupts this α-helix and abolished binding to
Gβ5-RGS7. Introduction of the double Pro substitution into full-length
M3R (M3RTP/LP) prevents trafficking of the receptor to
the cell surface. Using atropine or other antagonists as pharmacologic
chaperones, we were able to increase the level of surface expression
of the TP/LP mutant to levels comparable to that of wild-type M3R.
However, M3R-stimulated calcium signaling is still severely compromised.
These results show that the interaction of M3R with Gβ5-RGS7
requires helix 8 and the central portion of the i3 loop.
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Affiliation(s)
- Darla Karpinsky-Semper
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine , 1600 NW 10th Avenue, RMSB6024A, Miami, Florida 33136, United States
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Sensoy O, Weinstein H. A mechanistic role of Helix 8 in GPCRs: Computational modeling of the dopamine D2 receptor interaction with the GIPC1-PDZ-domain. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:976-83. [PMID: 25592838 DOI: 10.1016/j.bbamem.2014.12.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 11/15/2014] [Accepted: 12/02/2014] [Indexed: 01/18/2023]
Abstract
Helix-8 (Hx8) is a structurally conserved amphipathic helical motif in class-A GPCRs, adjacent to the C-terminal sequence that is responsible for PDZ-domain-recognition. The Hx8 segment in the dopamine D2 receptor (D2R) constitutes the C-terminal segment and we investigate its role in the function of D2R by studying the interaction with the PDZ-containing GIPC1 using homology models based on the X-ray structures of very closely related analogs: the D3R for the D2R model, and the PDZ domain of GIPC2 for GIPC1-PDZ. The mechanism of this interaction was investigated with all-atom unbiased molecular dynamics (MD) simulations that reveal the role of the membrane in maintaining the helical fold of Hx8, and with biased MD simulations to elucidate the energy drive for the interaction with the GIPC1-PDZ. We found that it becomes more favorable energetically for Hx8 to adopt the extended conformation observed in all PDZ-ligand complexes when it moves away from the membrane, and that C-terminus palmitoylation of D2R enhanced membrane penetration by the Hx8 backbone. De-palmitoylation enables Hx8 to move out into the aqueous environment for interaction with the PDZ domain. All-atom unbiased MD simulations of the full D2R-GIPC1-PDZ complex in sphingolipid/cholesterol membranes show that the D2R carboxyl C-terminus samples the region of the conserved GFGL motif located on the carboxylate-binding loop of the GIPC1-PDZ, and the entire complex distances itself from the membrane interface. Together, these results outline a likely mechanism of Hx8 involvement in the interaction of the GPCR with PDZ-domains in the course of signaling.
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Affiliation(s)
- Ozge Sensoy
- Department of Physiology and Biophysics, Weill Medical College of Cornell University, New York, NY, USA
| | - Harel Weinstein
- Department of Physiology and Biophysics, Weill Medical College of Cornell University, New York, NY, USA.
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18
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Obinata H, Gutkind S, Stitham J, Okuno T, Yokomizo T, Hwa J, Hla T. Individual variation of human S1P₁ coding sequence leads to heterogeneity in receptor function and drug interactions. J Lipid Res 2014; 55:2665-75. [PMID: 25293589 DOI: 10.1194/jlr.p054163] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sphingosine 1-phosphate receptor 1 (S1P₁), an abundantly-expressed G protein-coupled receptor which regulates key vascular and immune responses, is a therapeutic target in autoimmune diseases. Fingolimod/Gilenya (FTY720), an oral medication for relapsing-remitting multiple sclerosis, targets S1P₁ receptors on immune and neural cells to suppress neuroinflammation. However, suppression of endothelial S1P₁ receptors is associated with cardiac and vascular adverse effects. Here we report the genetic variations of the S1P₁ coding region from exon sequencing of >12,000 individuals and their functional consequences. We conducted functional analyses of 14 nonsynonymous single nucleotide polymorphisms (SNPs) of the S1PR1 gene. One SNP mutant (Arg¹²⁰ to Pro) failed to transmit sphingosine 1-phosphate (S1P)-induced intracellular signals such as calcium increase and activation of p44/42 MAPK and Akt. Two other mutants (Ile⁴⁵ to Thr and Gly³⁰⁵ to Cys) showed normal intracellular signals but impaired S1P-induced endocytosis, which made the receptor resistant to FTY720-induced degradation. Another SNP mutant (Arg¹³ to Gly) demonstrated protection from coronary artery disease in a high cardiovascular risk population. Individuals with this mutation showed a significantly lower percentage of multi-vessel coronary obstruction in a risk factor-matched case-control study. This study suggests that individual genetic variations of S1P₁ can influence receptor function and, therefore, infer differential disease risks and interaction with S1P₁-targeted therapeutics.
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Affiliation(s)
- Hideru Obinata
- Center for Vascular Biology, Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, Cornell University, New York, NY 10065
| | - Sarah Gutkind
- Center for Vascular Biology, Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, Cornell University, New York, NY 10065
| | - Jeremiah Stitham
- Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06510
| | - Toshiaki Okuno
- Department of Biochemistry, Juntendo University School of Medicine, Tokyo 113-8421, Japan
| | - Takehiko Yokomizo
- Department of Biochemistry, Juntendo University School of Medicine, Tokyo 113-8421, Japan
| | - John Hwa
- Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06510
| | - Timothy Hla
- Center for Vascular Biology, Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, Cornell University, New York, NY 10065
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Bäck M, Powell WS, Dahlén SE, Drazen JM, Evans JF, Serhan CN, Shimizu T, Yokomizo T, Rovati GE. Update on leukotriene, lipoxin and oxoeicosanoid receptors: IUPHAR Review 7. Br J Pharmacol 2014; 171:3551-74. [PMID: 24588652 DOI: 10.1111/bph.12665] [Citation(s) in RCA: 155] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 02/06/2014] [Accepted: 02/18/2014] [Indexed: 12/14/2022] Open
Abstract
The endogenous ligands for the LT, lipoxin (LX) and oxoeicosanoid receptors are bioactive products produced by the action of the lipoxygenase family of enzymes. The LT receptors BLT1 and BLT2 , are activated by LTB4 and the CysLT1 and CysLT2 receptors are activated by the cysteinyl-LTs, whereas oxoeicosanoids exert their action through the OXE receptor. In contrast to these pro-inflammatory mediators, LXA4 transduces responses associated with the resolution of inflammation through the receptor FPR2/ALX (ALX/FPR2). The aim of the present review is to give a state of the field on these receptors, with focus on recent important findings. For example, BLT1 receptor signalling in cancer and the dual role of the BLT2 receptor in pro- and anti-inflammatory actions have added more complexity to lipid mediator signalling. Furthermore, a cross-talk between the CysLT and P2Y receptor systems has been described, and also the presence of novel receptors for cysteinyl-LTs, such as GPR17 and GPR99. Finally, lipoxygenase metabolites derived from ω-3 essential polyunsaturated acids, the resolvins, activate the receptors GPR32 and ChemR23. In conclusion, the receptors for the lipoxygenase products make up a sophisticated and tightly controlled system of endogenous pro- and anti-inflammatory signalling in physiology and pathology.
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Affiliation(s)
- Magnus Bäck
- Nomenclature Subcommittee for Leukotriene Receptors, International Union of Basic and Clinical Pharmacology, Stockholm, Sweden; Department of Medicine, Karolinska Institutet, Stockholm, Sweden; Department of Cardiology, Karolinska University Hospital, Stockholm, Sweden
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Rognan D, Mus-Veteau I. Three-Dimensional Structure of the Smoothened Receptor: Implications for Drug Discovery. TOPICS IN MEDICINAL CHEMISTRY 2014. [DOI: 10.1007/7355_2014_64] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
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Matsunaga Y, Fukuyama S, Okuno T, Sasaki F, Matsunobu T, Asai Y, Matsumoto K, Saeki K, Oike M, Sadamura Y, Machida K, Nakanishi Y, Kubo M, Yokomizo T, Inoue H. Leukotriene B4 receptor BLT2 negatively regulates allergic airway eosinophilia. FASEB J 2013; 27:3306-14. [PMID: 23603839 DOI: 10.1096/fj.12-217000] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Leukotriene B4 (LTB4) has been implicated in the pathogenesis of allergic diseases. BLT2, a low-affinity LTB4 receptor, is activated by LTB4 and 12(S)-hydroxyheptadeca-5Z,8E,10E-trienoic acid (12-HHT). Although the high-affinity LTB4 receptor BLT1 has been shown to exert proinflammatory roles, the role of BLT2 in allergic inflammation has not been clarified. To study the function of BLT2 in development of asthma, we used mice model of ovalbumin (OVA)-induced allergic airway disease. The 12-HHT levels were elevated in bronchoalveolar lavage (BAL) fluids of OVA-sensitized/challenged wild-type mice. BLT2-deficient mice exhibited enhanced eosinophilia in BAL fluids after OVA exposure. Interleukin (IL)-13 levels in BAL fluids and IL-13-producing CD4(+) T cells in the lungs were elevated in BLT2-deficient mice compared to wild-type mice, whereas the levels of IL-4, IL-5, and interferon (IFN)-γ in BAL fluids and serum OVA-specific IgE were comparable. Transfection of BLT2-specific small interfering RNA enhanced IL-13 production in CD4(+) T cells in vitro. Expression of BLT2 mRNA in CD4(+) T cells was significantly reduced in patients with asthma compared to healthy control subjects. These findings indicate that BLT2 has a protective role in allergic airway inflammation and that diminished BLT2 expression in CD4(+) T cells may contribute to the pathophysiology of asthma.
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Affiliation(s)
- Yuko Matsunaga
- Research Institute for Diseases of the Chest, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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