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Larsen O, Lückmann M, van der Velden WJC, Oliva-Santiago M, Brvar M, Ulven T, Frimurer TM, Karlshøj S, Rosenkilde MM. Selective Allosteric Modulation of N-Terminally Cleaved, but Not Full Length CCL3 in CCR1. ACS Pharmacol Transl Sci 2019; 2:429-441. [PMID: 32259075 DOI: 10.1021/acsptsci.9b00059] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Indexed: 11/29/2022]
Abstract
Chemokines undergo post-translational modification such as N-terminal truncations. Here, we describe how N-terminal truncation of full length CCL3(1-70) affects its activity at CCR1. Truncated CCL3(5-70) has 10-fold higher potency and enhanced efficacy in β-arrestin recruitment, but less than 2-fold increased potencies in G protein signaling determined by calcium release, cAMP and IP3 formation. Small positive ago-allosteric ligands modulate the two CCL3 variants differently as the metal ion chelator bipyridine in complex with zinc (ZnBip) enhances the binding of truncated, but not full length CCL3, while a size-increase of the chelator to a chloro-substituted terpyridine (ZnClTerp), eliminates its allosteric, but not agonistic action. By employing a series of receptor mutants and in silico modeling we describe residues of importance for chemokine and small molecule binding. Notably, the chemokine receptor-conserved Glu2877.39 interacts with the N-terminal amine of truncated CCL3(5-70) and with Zn2+ of ZnBip, thereby bridging their binding sites and enabling the positive allosteric effect. Our study emphasizes that small allosteric molecules may act differently toward chemokine variants and thus selectively modulate interactions of specific chemokine subsets with their cognate receptors.
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Affiliation(s)
- Olav Larsen
- Laboratory for Molecular Pharmacology, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark
| | - Michael Lückmann
- Section for Metabolic Receptology, Novo Nordisk Foundation, Center for Basic Metabolic Research, Blegdamsvej 3, DK-2200 Copenhagen, Denmark
| | - Wijnand J C van der Velden
- Laboratory for Molecular Pharmacology, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark
| | - Marta Oliva-Santiago
- Laboratory for Molecular Pharmacology, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark
| | - Matjaz Brvar
- Department of Physics and Chemistry, University of Southern Denmark, Campusvej 55, DK-5230 Odense, Denmark
| | - Trond Ulven
- Department of Physics and Chemistry, University of Southern Denmark, Campusvej 55, DK-5230 Odense, Denmark.,Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2200 Copenhagen, Denmark
| | - Thomas M Frimurer
- Section for Metabolic Receptology, Novo Nordisk Foundation, Center for Basic Metabolic Research, Blegdamsvej 3, DK-2200 Copenhagen, Denmark
| | - Stefanie Karlshøj
- Laboratory for Molecular Pharmacology, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark
| | - Mette M Rosenkilde
- Laboratory for Molecular Pharmacology, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark
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2
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Floss DM, Scheller J. Naturally occurring and synthetic constitutive-active cytokine receptors in disease and therapy. Cytokine Growth Factor Rev 2019; 47:1-20. [PMID: 31147158 DOI: 10.1016/j.cytogfr.2019.05.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 05/15/2019] [Indexed: 02/07/2023]
Abstract
Cytokines control immune related events and are critically involved in a plethora of patho-physiological processes including autoimmunity and cancer development. Mutations which cause ligand-independent, constitutive activation of cytokine receptors are quite frequently found in diseases. Many constitutive-active cytokine receptor variants have been directly connected to disease development and mechanistically analyzed. Nature's solutions to generate constitutive cytokine receptors has been recently adopted by synthetic cytokine receptor biology, with the goal to optimize immune therapeutics. Here, CAR T cell immmunotherapy represents the first example to combine synthetic biology with genetic engineering during therapy. Hence, constitutive-active cytokine receptors are therapeutic targets, but also emerging tools to improve or modulate immunotherapeutic strategies. This review gives a comprehensive insight into the field of naturally occurring and synthetic constitutive-active cytokine receptors.
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Affiliation(s)
- Doreen M Floss
- Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany.
| | - Jürgen Scheller
- Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
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3
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Jørgensen AS, Adogamhe PE, Laufer JM, Legler DF, Veldkamp CT, Rosenkilde MM, Hjortø GM. CCL19 with CCL21-tail displays enhanced glycosaminoglycan binding with retained chemotactic potency in dendritic cells. J Leukoc Biol 2018; 104:401-411. [PMID: 29768676 DOI: 10.1002/jlb.2vma0118-008r] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Revised: 03/13/2018] [Accepted: 03/13/2018] [Indexed: 12/23/2022] Open
Abstract
CCL19 is more potent than CCL21 in inducing chemotaxis of human dendritic cells (DC). This difference is attributed to 1) a stronger interaction of the basic C-terminal tail of CCL21 with acidic glycosaminoglycans (GAGs) in the environment and 2) an autoinhibitory function of this C-terminal tail. Moreover, different receptor docking modes and tissue expression patterns of CCL19 and CCL21 contribute to fine-tuned control of CCR7 signaling. Here, we investigate the effect of the tail of CCL21 on chemokine binding to GAGs and on CCR7 activation. We show that transfer of CCL21-tail to CCL19 (CCL19CCL21-tail ) markedly increases binding of CCL19 to human dendritic cell surfaces, without impairing CCL19-induced intracellular calcium release or DC chemotaxis, although it causes reduced CCR7 internalization. The more potent chemotaxis induced by CCL19 and CCL19CCL21-tail compared to CCL21 is not transferred to CCL21 by replacing its N-terminus with that of CCL19 (CCL21CCL19-N-term ). Measurements of cAMP production in CHO cells uncover that CCL21-tail transfer (CCL19CCL21-tail ) negatively affects CCL19 potency, whereas removal of CCL21-tail (CCL21tailless ) increases signaling compared to full-length CCL21, indicating that the tail negatively affects signaling via cAMP. Similar to chemokine-driven calcium mobilization and chemotaxis, the potency of CCL21 in cAMP is not improved by transfer of the CCL19 N-terminus to CCL21 (CCL21CCL19-N-term ). Together these results indicate that ligands containing CCL21 core and C-terminal tail (CCL21 and CCL21CCL19-N-term ) are most restricted in their cAMP signaling; a phenotype attributed to a stronger GAG binding of CCL21 and defined structural differences between CCL19 and CCL21.
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Affiliation(s)
- Astrid S Jørgensen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, The Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Pontian E Adogamhe
- Department of Chemistry, University of Wisconsin-Whitewater, Whitewater, Wisconsin, USA
| | - Julia M Laufer
- Biotechnology Institute Thurgau (BITg), at the University of Konstanz, Kreuzlingen, Switzerland
| | - Daniel F Legler
- Biotechnology Institute Thurgau (BITg), at the University of Konstanz, Kreuzlingen, Switzerland
| | | | - Mette M Rosenkilde
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, The Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Gertrud M Hjortø
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, The Panum Institute, University of Copenhagen, Copenhagen, Denmark
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4
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Berg C, Daugvilaite V, Steen A, Jørgensen AS, Våbenø J, Rosenkilde MM. Inhibition of HIV Fusion by Small Molecule Agonists through Efficacy-Engineering of CXCR4. ACS Chem Biol 2018; 13:881-886. [PMID: 29461034 DOI: 10.1021/acschembio.8b00061] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
CXC chemokine receptor 4 (CXCR4) is involved in multiple physiological and pathological processes, notably as a coreceptor for human immunodeficiency virus (HIV) cell entry. Its broad expression pattern and vital biological importance make CXCR4 a troublesome drug target, as disruption of the interaction with its endogenous ligand, CXC chemokine ligand 12 (CXCL12), has severe consequences. In fact, only one CXCR4 drug, the bicyclam antagonist and HIV entry inhibitor AMD3100 (Plerixafor/Mozobil), has been approved for clinical use, however only for stem cell mobilization-a consequence of CXCR4 antagonism. Here, we report the engineering of an efficacy switch mutation in CXCR4-F292A7.43 in the middle of transmembrane helix 7-that converted the antagonists AMD3100 and AMD11070 into partial agonists. As agonists on F292A CXCR4, AMD3100 and AMD11070 were less disruptive to CXCR4 signaling while they remained efficient inhibitors of HIV fusion. This demonstrates that small molecule CXCR4 agonists can have a therapeutic potential as HIV entry inhibitors.
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Affiliation(s)
- Christian Berg
- Laboratory for Molecular Pharmacology, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark
- Infectious Diseases Unit, Department of Medicine, Herlev−Gentofte Hospital, Herlev Ringvej 75, 2730 Herlev, Denmark
| | - Viktorija Daugvilaite
- Laboratory for Molecular Pharmacology, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark
| | - Anne Steen
- Laboratory for Molecular Pharmacology, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark
| | - Astrid Sissel Jørgensen
- Laboratory for Molecular Pharmacology, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark
| | - Jon Våbenø
- Helgeland Hospital Trust, Prestmarkveien 1, 8800 Sandnessjøen, Norway
| | - Mette Marie Rosenkilde
- Laboratory for Molecular Pharmacology, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark
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5
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Jørgensen AS, Rosenkilde MM, Hjortø GM. Biased signaling of G protein-coupled receptors - From a chemokine receptor CCR7 perspective. Gen Comp Endocrinol 2018; 258:4-14. [PMID: 28694053 DOI: 10.1016/j.ygcen.2017.07.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 07/03/2017] [Accepted: 07/06/2017] [Indexed: 12/22/2022]
Abstract
Chemokines (chemotactic cytokines) and their associated G protein-coupled receptors (GPCRs) work in a concerted manner to govern immune cell positioning in time and space. Promiscuity of both ligands and receptors, but also biased signaling within the chemokine system, adds to the complexity of how the cell-based immune system is controlled. Bias comes in three forms; ligand-, receptor- and tissue-bias. Biased signaling is increasingly being recognized as playing an important role in contributing to the fine-tuned coordination of immune cell chemotaxis. In the current review we discuss the recent findings related to ligand- and tissue-biased signaling of CCR7 and summarize what is known about bias at other chemokine receptors. CCR7 is expressed by a subset of T-cells and by mature dendritic cells (DCs). Together with its two endogenous ligands CCL19 and CCL21, of which the carboxy terminal tail of CCL21 displays an extraordinarily strong glycosaminoglycan (GAG) binding, CCR7 plays a central role in coordinating the meeting between mature antigen presenting DCs and naïve T-cells which normally takes place in the lymph nodes (LNs). This process is a prerequisite for the initiation of an antigen-specific T-cell mediated immune response. Thus CCR7 and its ligands are key players in initiating cell-based immune responses. CCL19 and CCL21 display differential interaction- and docking-modes for CCR7 leading to stabilization of different CCR7 conformations and hereby preferential activation of distinct intracellular signaling pathways (i.e. ligand bias). In general CCL19 seems to generate a strong temporal signal, whereas CCL21 generates a weaker, but more persistent signal. Tissue differential expression of these two ligands, and the generation of a third ligand "tailless-CCL21", through DC specific protease activity (tissue bias), orchestrates DC and T-cell LN homing and priming, with each ligand serving overlapping, but also distinct roles.
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Affiliation(s)
- Astrid Sissel Jørgensen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, The Panum Institute, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark
| | - Mette M Rosenkilde
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, The Panum Institute, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark
| | - Gertrud M Hjortø
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, The Panum Institute, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark.
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6
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Hjortø GM, Larsen O, Steen A, Daugvilaite V, Berg C, Fares S, Hansen M, Ali S, Rosenkilde MM. Differential CCR7 Targeting in Dendritic Cells by Three Naturally Occurring CC-Chemokines. Front Immunol 2016; 7:568. [PMID: 28018341 PMCID: PMC5145889 DOI: 10.3389/fimmu.2016.00568] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 11/22/2016] [Indexed: 01/07/2023] Open
Abstract
The CCR7 ligands CCL19 and CCL21 are increasingly recognized as functionally different (biased). Using mature human dendritic cells (DCs), we show that CCL19 is more potent than CCL21 in inducing 3D chemotaxis. Intriguingly, CCL21 induces prolonged and more efficient ERK1/2 activation compared with CCL19 and a C-terminal truncated (tailless) CCL21 in DCs. In contrast, tailless-CCL21 displays increased potency in DC chemotaxis compared with native CCL21. Using a CCL21-specific antibody, we show that CCL21, but not tailless-CCL21, accumulates at the cell surface. In addition, removal of sialic acid from the cell surface by neuraminidase treatment impairs ERK1/2 activation by CCL21, but not by CCL19 or tailless-CCL21. Using standard laboratory cell lines, we observe low potency of both CCL21 and tailless-CCL21 in G protein activation and β-arrestin recruitment compared with CCL19, indicating that the tail itself does not improve receptor interaction. Chemokines interact with their receptors in a stepwise manner with ultimate docking of their N-terminus into the main binding pocket. Employing site-directed mutagenesis we identify residues in this pocket of selective CCL21 importance. We also identify a molecular switch in the top of TM7 important for keeping CCR7 in an inactive conformation (Tyr312), as introduction of the chemokine receptor-conserved Glu (or Ala) induces high constitutive activity. Summarized, we show that the interaction of the tail of CCL21 with polysialic acid is needed for strong ERK signaling, whereas it impairs CCL21-mediated chemotaxis and has no impact on receptor docking consistent with the current model of chemokine:receptor interaction. This indicates that future selective pharmacological targeting of CCL19 versus CCL21 should focus on a differential targeting of the main receptor pocket, while selective targeting of tailless-CCL21 versus CCL21 and CCL19 requires targeting of the glycosaminoglycan (GAG) interaction.
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Affiliation(s)
- Gertrud M Hjortø
- Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, The Panum Institute, University of Copenhagen , Copenhagen , Denmark
| | - Olav Larsen
- Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, The Panum Institute, University of Copenhagen , Copenhagen , Denmark
| | - Anne Steen
- Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, The Panum Institute, University of Copenhagen , Copenhagen , Denmark
| | - Viktorija Daugvilaite
- Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, The Panum Institute, University of Copenhagen , Copenhagen , Denmark
| | - Christian Berg
- Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, The Panum Institute, University of Copenhagen , Copenhagen , Denmark
| | - Suzan Fares
- Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, The Panum Institute, University of Copenhagen , Copenhagen , Denmark
| | - Morten Hansen
- Department of Haematology, Center for Cancer Immune Therapy (CCIT), Copenhagen University Hospital , Herlev , Denmark
| | - Simi Ali
- Medical Faculty, Institute of Cellular Medicine, Newcastle University , Newcastle upon Tyne , UK
| | - Mette M Rosenkilde
- Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, The Panum Institute, University of Copenhagen , Copenhagen , Denmark
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7
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Karlshøj S, Amarandi RM, Larsen O, Daugvilaite V, Steen A, Brvar M, Pui A, Frimurer TM, Ulven T, Rosenkilde MM. Molecular Mechanism of Action for Allosteric Modulators and Agonists in CC-chemokine Receptor 5 (CCR5). J Biol Chem 2016; 291:26860-26874. [PMID: 27834679 DOI: 10.1074/jbc.m116.740183] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2016] [Revised: 11/09/2016] [Indexed: 12/22/2022] Open
Abstract
The small molecule metal ion chelators bipyridine and terpyridine complexed with Zn2+ (ZnBip and ZnTerp) act as CCR5 agonists and strong positive allosteric modulators of CCL3 binding to CCR5, weak modulators of CCL4 binding, and competitors for CCL5 binding. Here we describe their binding site using computational modeling, binding, and functional studies on WT and mutated CCR5. The metal ion Zn2+ is anchored to the chemokine receptor-conserved Glu-283VII:06/7.39 Both chelators interact with aromatic residues in the transmembrane receptor domain. The additional pyridine ring of ZnTerp binds deeply in the major binding pocket and, in contrast to ZnBip, interacts directly with the Trp-248VI:13/6.48 microswitch, contributing to its 8-fold higher potency. The impact of Trp-248 was further confirmed by ZnClTerp, a chloro-substituted version of ZnTerp that showed no inherent agonism but maintained positive allosteric modulation of CCL3 binding. Despite a similar overall binding mode of all three metal ion chelator complexes, the pyridine ring of ZnClTerp blocks the conformational switch of Trp-248 required for receptor activation, thereby explaining its lack of activity. Importantly, ZnClTerp becomes agonist to the same extent as ZnTerp upon Ala mutation of Ile-116III:16/3.40, a residue that constrains the Trp-248 microswitch in its inactive conformation. Binding studies with 125I-CCL3 revealed an allosteric interface between the chemokine and the small molecule binding site, including residues Tyr-37I:07/1.39, Trp-86II:20/2.60, and Phe-109III:09/3.33 The small molecules and CCL3 approach this interface from opposite directions, with some residues being mutually exploited. This study provides new insight into the molecular mechanism of CCR5 activation and paves the way for future allosteric drugs for chemokine receptors.
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Affiliation(s)
- Stefanie Karlshøj
- From the Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark
| | - Roxana Maria Amarandi
- From the Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark.,the Faculty of Chemistry, Alexandru Ioan Cuza University of Iaşi, Bd. Carol I No. 11, RO-700506 Iaşi, Romania
| | - Olav Larsen
- From the Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark
| | - Viktorija Daugvilaite
- From the Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark
| | - Anne Steen
- From the Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark
| | - Matjaž Brvar
- the Department of Physics and Chemistry, University of Southern Denmark, Campusvej 55, DK-5230 Odense, Denmark
| | - Aurel Pui
- the Faculty of Chemistry, Alexandru Ioan Cuza University of Iaşi, Bd. Carol I No. 11, RO-700506 Iaşi, Romania
| | - Thomas Michael Frimurer
- the Novo Nordisk Foundation Center for Basic Metabolic Research, Section for Metabolic Receptology and Enteroendocrinology, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark, and
| | - Trond Ulven
- the Department of Physics and Chemistry, University of Southern Denmark, Campusvej 55, DK-5230 Odense, Denmark
| | - Mette Marie Rosenkilde
- From the Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark,
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8
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Berg C, Spiess K, Lüttichau HR, Rosenkilde MM. Biased small-molecule ligands for selective inhibition of HIV-1 cell entry via CCR5. Pharmacol Res Perspect 2016; 4:e00262. [PMID: 28097000 PMCID: PMC5226280 DOI: 10.1002/prp2.262] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 08/16/2016] [Indexed: 12/31/2022] Open
Abstract
Since the discovery of HIV's use of CCR5 as the primary coreceptor in fusion, the focus on developing small-molecule receptor antagonists for inhibition hereof has only resulted in one single drug, Maraviroc. We therefore investigated the possibility of using small-molecule CCR5 agonists as HIV-1 fusion inhibitors. A virus-free cell-based fusion reporter assay, based on mixing "effector cells" (expressing HIV Env and luciferase activator) with "target cells" (expressing CD4, CCR5 wild type or a selection of well-described mutations, and luciferase reporter), was used as fusion readout. Receptor expression was evaluated by ELISA and fluorescence microscopy. On CCR5 WT, Maraviroc and Aplaviroc inhibited fusion with high potencies (EC 50 values of 91 and 501 nM, respectively), whereas removal of key residues for both antagonists (Glu283Ala) or Maraviroc alone (Tyr251Ala) prevented fusion inhibition, establishing this assay as suitable for screening of HIV entry inhibitors. Both ligands inhibited HIV fusion on signaling-deficient CCR5 mutations (Tyr244Ala and Trp248Ala). Moreover, the steric hindrance CCR5 mutation (Gly286Phe) impaired fusion, presumably by a direct hindrance of gp120 interaction. Finally, the efficacy switch mutation (Leu203Phe) - converting small-molecule antagonists/inverse agonists to full agonists biased toward G-protein activation - uncovered that also small-molecule agonists can function as direct HIV-1 cell entry inhibitors. Importantly, no agonist-induced receptor internalization was observed for this mutation. Our studies of the pharmacodynamic requirements for HIV-1 fusion inhibitors highlight the possibility of future development of biased ligands with selective targeting of the HIV-CCR5 interaction without interfering with the normal functionality of CCR5.
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Affiliation(s)
- Christian Berg
- Department of Neuroscience and PharmacologyFaculty of Health and Medical SciencesThe Panum InstituteUniversity of CopenhagenCopenhagenDenmark
| | - Katja Spiess
- Department of Neuroscience and PharmacologyFaculty of Health and Medical SciencesThe Panum InstituteUniversity of CopenhagenCopenhagenDenmark
| | - Hans R. Lüttichau
- Department of Neuroscience and PharmacologyFaculty of Health and Medical SciencesThe Panum InstituteUniversity of CopenhagenCopenhagenDenmark
- Department of MedicineInfectious Disease UnitHerlev HospitalCopenhagenDenmark
| | - Mette M. Rosenkilde
- Department of Neuroscience and PharmacologyFaculty of Health and Medical SciencesThe Panum InstituteUniversity of CopenhagenCopenhagenDenmark
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9
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Vacchini A, Locati M, Borroni EM. Overview and potential unifying themes of the atypical chemokine receptor family. J Leukoc Biol 2016; 99:883-92. [PMID: 26740381 DOI: 10.1189/jlb.2mr1015-477r] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 12/12/2015] [Indexed: 12/17/2022] Open
Abstract
Chemokines modulate immune responses through their ability to orchestrate the migration of target cells. Chemokines directly induce cell migration through a distinct set of 7 transmembrane domain G protein-coupled receptors but are also recognized by a small subfamily of atypical chemokine receptors, characterized by their inability to support chemotactic activity. Atypical chemokine receptors are now emerging as crucial regulatory components of chemokine networks in a wide range of physiologic and pathologic contexts. Although a new nomenclature has been approved recently to reflect their functional distinction from their conventional counterparts, a systematic view of this subfamily is still missing. This review discusses their biochemical and immunologic properties to identify potential unifying themes in this emerging family.
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Affiliation(s)
- Alessandro Vacchini
- Department of Medical Biotechnologies and Translational Medicine, University of Milan, and Humanitas Clinical and Research Center, Milan, Italy
| | - Massimo Locati
- Department of Medical Biotechnologies and Translational Medicine, University of Milan, and Humanitas Clinical and Research Center, Milan, Italy
| | - Elena Monica Borroni
- Department of Medical Biotechnologies and Translational Medicine, University of Milan, and Humanitas Clinical and Research Center, Milan, Italy
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10
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Abstract
Biased signaling or functional selectivity occurs when a 7TM-receptor preferentially activates one of several available pathways. It can be divided into three distinct forms: ligand bias, receptor bias, and tissue or cell bias, where it is mediated by different ligands (on the same receptor), different receptors (with the same ligand), or different tissues or cells (for the same ligand–receptor pair). Most often biased signaling is differentiated into G protein-dependent and β-arrestin-dependent signaling. Yet, it may also cover signaling differences within these groups. Moreover, it may not be absolute, i.e., full versus no activation. Here we discuss biased signaling in the chemokine system, including the structural basis for biased signaling in chemokine receptors, as well as in class A 7TM receptors in general. This includes overall helical movements and the contributions of micro-switches based on recently published 7TM crystals and molecular dynamics studies. All three forms of biased signaling are abundant in the chemokine system. This challenges our understanding of “classic” redundancy inevitably ascribed to this system, where multiple chemokines bind to the same receptor and where a single chemokine may bind to several receptors – in both cases with the same functional outcome. The ubiquitous biased signaling confers a hitherto unknown specificity to the chemokine system with a complex interaction pattern that is better described as promiscuous with context-defined roles and different functional outcomes in a ligand-, receptor-, or cell/tissue-defined manner. As the low number of successful drug development plans implies, there are great difficulties in targeting chemokine receptors; in particular with regard to receptor antagonists as anti-inflammatory drugs. Un-defined and putative non-selective targeting of the complete cellular signaling system could be the underlying cause of lack of success. Therefore, biased ligands could be the solution.
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Affiliation(s)
- Anne Steen
- Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark
| | - Olav Larsen
- Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark
| | - Stefanie Thiele
- Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark
| | - Mette M Rosenkilde
- Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark
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