1
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Kaffashi K, Dréau D, Nesmelova IV. Heterodimers Are an Integral Component of Chemokine Signaling Repertoire. Int J Mol Sci 2023; 24:11639. [PMID: 37511398 PMCID: PMC10380872 DOI: 10.3390/ijms241411639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 07/10/2023] [Accepted: 07/11/2023] [Indexed: 07/30/2023] Open
Abstract
Chemokines are a family of signaling proteins that play a crucial role in cell-cell communication, cell migration, and cell trafficking, particularly leukocytes, under both normal and pathological conditions. The oligomerization state of chemokines influences their biological activity. The heterooligomerization occurs when multiple chemokines spatially and temporally co-localize, and it can significantly affect cellular responses. Recently, obligate heterodimers have emerged as tools to investigate the activities and molecular mechanisms of chemokine heterodimers, providing valuable insights into their functional roles. This review focuses on the latest progress in understanding the roles of chemokine heterodimers and their contribution to the functioning of the chemokine network.
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Affiliation(s)
- Kimia Kaffashi
- Department of Biological Sciences, University of North Carolina, Charlotte, NC 28223, USA
- Department of Physics and Optical Sciences, University of North Carolina, Charlotte, NC 28223, USA
| | - Didier Dréau
- Department of Biological Sciences, University of North Carolina, Charlotte, NC 28223, USA
| | - Irina V Nesmelova
- Department of Physics and Optical Sciences, University of North Carolina, Charlotte, NC 28223, USA
- School of Data Science, University of North Carolina, Charlotte, NC 28223, USA
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2
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Thompson S, Pang CY, Sepuru KM, Cambier S, Hellyer TP, Scott J, Simpson AJ, Proost P, Kirby JA, Rajarathnam K, Sheerin NS, Ali S. Nitration of chemokine CXCL8 acts as a natural mechanism to limit acute inflammation. Cell Mol Life Sci 2023; 80:35. [PMID: 36622452 PMCID: PMC9829591 DOI: 10.1007/s00018-022-04663-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 11/24/2022] [Accepted: 12/09/2022] [Indexed: 01/10/2023]
Abstract
Chemokine CXCL8 is a key facilitator of the human host immune response, mediating neutrophil migration, and activation at the site of infection and injury. The oxidative burst is an important effector mechanism which leads to the generation of reactive nitrogen species (RNS), including peroxynitrite. The current study was performed to determine the potential for nitration to alter the biological properties of CXCL8 and its detection in human disease. Here, we show peroxynitrite nitrates CXCL8 and thereby regulates neutrophil migration and activation. The nitrated chemokine was unable to induce transendothelial neutrophil migration in vitro and failed to promote leukocyte recruitment in vivo. This reduced activity is due to impairment in both G protein-coupled receptor signaling and glycosaminoglycan binding. Using a novel antibody, nitrated CXCL8 was detected in bronchoalveolar lavage samples from patients with pneumonia. These findings were validated by mass spectrometry. Our results provide the first direct evidence of chemokine nitration in human pathophysiology and suggest a natural mechanism that limits acute inflammation.
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Affiliation(s)
- Sarah Thompson
- Immunity and Inflammation Theme, Faculty of Medical Sciences, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Chong Yun Pang
- Immunity and Inflammation Theme, Faculty of Medical Sciences, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Krishna Mohan Sepuru
- Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics, The University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Seppe Cambier
- Department of Microbiology, Immunology and Transplantation, Rega Institute, KU Leuven, 3000, Leuven, Belgium
| | - Thomas P Hellyer
- Immunity and Inflammation Theme, Faculty of Medical Sciences, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
- Department of Critical Care Medicine, Royal Victoria Infirmary, Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle Upon Tyne, NE1 4LP, UK
| | - Jonathan Scott
- Immunity and Inflammation Theme, Faculty of Medical Sciences, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - A John Simpson
- Immunity and Inflammation Theme, Faculty of Medical Sciences, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
- Department of Respiratory Medicine, Royal Victoria Infirmary, Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, NE1 4L9, UK
| | - Paul Proost
- Department of Microbiology, Immunology and Transplantation, Rega Institute, KU Leuven, 3000, Leuven, Belgium
| | - John A Kirby
- Immunity and Inflammation Theme, Faculty of Medical Sciences, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Krishna Rajarathnam
- Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics, The University of Texas Medical Branch, Galveston, TX, 77555, USA.
- Institute for Human Infections and Immunity, The University of Texas Medical Branch, Galveston, TX, 77555, USA.
| | - Neil S Sheerin
- Immunity and Inflammation Theme, Faculty of Medical Sciences, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.
| | - Simi Ali
- Immunity and Inflammation Theme, Faculty of Medical Sciences, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.
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3
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McKenna S, Giblin SP, Bunn RA, Xu Y, Matthews SJ, Pease JE. A highly efficient method for the production and purification of recombinant human CXCL8. PLoS One 2021; 16:e0258270. [PMID: 34653205 PMCID: PMC8519433 DOI: 10.1371/journal.pone.0258270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 09/22/2021] [Indexed: 12/02/2022] Open
Abstract
Chemokines play diverse and fundamental roles in the immune system and human disease, which has prompted their structural and functional characterisation. Production of recombinant chemokines that are folded and bioactive is vital to their study but is limited by the stringent requirements of a native N-terminus for receptor activation and correct disulphide bonding required to stabilise the chemokine fold. Even when expressed as fusion proteins, overexpression of chemokines in E. coli tends to result in the formation of inclusion bodies, generating the additional steps of solubilisation and refolding. Here we present a novel method for producing soluble chemokines in relatively large amounts via a simple two-step purification procedure with no requirements for refolding. CXCL8 produced by this method has the correct chemokine fold as determined by NMR spectroscopy and in chemotaxis assays was indistinguishable from commercially available chemokines. We believe that this protocol significantly streamlines the generation of recombinant chemokines.
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Affiliation(s)
- Sophie McKenna
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Sean Patrick Giblin
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Rosemarie Anne Bunn
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Yingqi Xu
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | | | - James Edward Pease
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
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4
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Latest update on chemokine receptors as therapeutic targets. Biochem Soc Trans 2021; 49:1385-1395. [PMID: 34060588 PMCID: PMC8286821 DOI: 10.1042/bst20201114] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 04/19/2021] [Accepted: 04/23/2021] [Indexed: 12/12/2022]
Abstract
The chemokine system plays a fundamental role in a diverse range of physiological processes, such as homeostasis and immune responses. Dysregulation in the chemokine system has been linked to inflammatory diseases and cancer, which renders chemokine receptors to be considered as therapeutic targets. In the past two decades, around 45 drugs targeting chemokine receptors have been developed, yet only three are clinically approved. The challenging factors include the limited understanding of aberrant chemokine signalling in malignant diseases, high redundancy of the chemokine system, differences between cell types and non-specific binding of the chemokine receptor antagonists due to the broad ligand-binding pockets. In recent years, emerging studies attempt to characterise the chemokine ligand–receptor interactions and the downstream signalling protein–protein interactions, aiming to fine tuning to the promiscuous interplay of the chemokine system for the development of precision medicine. This review will outline the updates on the mechanistic insights in the chemokine system and propose some potential strategies in the future development of targeted therapy.
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5
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Sepuru KM, Nair V, Prakash P, Gorfe AA, Rajarathnam K. Long-Range Coupled Motions Underlie Ligand Recognition by a Chemokine Receptor. iScience 2020; 23:101858. [PMID: 33344917 PMCID: PMC7736917 DOI: 10.1016/j.isci.2020.101858] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 11/02/2020] [Accepted: 11/19/2020] [Indexed: 12/28/2022] Open
Abstract
Chemokines are unusual class-A G protein-coupled receptor agonists because of their large size (∼10 kDa) and binding at two distinct receptor sites: N-terminal domain (Site-I, unique to chemokines) and a groove defined by extracellular loop/transmembrane helices (Site-II, shared with all small molecule class-A ligands). Structures and sequence analysis reveal that the receptor N-terminal domains (N-domains) are flexible and contain intrinsic disorder. Using a hybrid NMR-MD approach, we characterized the role of Site-I interactions for the CXCL8-CXCR1 pair. NMR data indicate that the CXCR1 N-domain becomes structured on binding and that the binding interface is extensive with 30% CXCL8 residues participating in this initial interaction. MD simulations indicate that CXCL8 bound at Site-I undergoes extensive reorganization on engaging Site-II with several residues initially engaged at Site-I also engaging at Site-II. We conclude that structural plasticity of Site-I interactions plays an active role in driving ligand recognition by a chemokine receptor. Structural plasticity governs chemokine-receptor interactions Receptor N-terminal domain captures the chemokine by a fly-casting mechanism Crosstalk between two distinct binding sites determines recognition and function A hybrid NMR-MD approach provides crucial insights into receptor binding mechanism
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Affiliation(s)
- Krishna Mohan Sepuru
- Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, TX 77555, USA.,Sealy Center for Structural Biology and Molecular Biophysics, The University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Vinay Nair
- Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA.,MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Priyanka Prakash
- Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Alemayehu A Gorfe
- Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA.,MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Krishna Rajarathnam
- Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, TX 77555, USA.,Department of Microbiology and Immunology, The University of Texas Medical Branch, Galveston, TX 77555, USA.,Sealy Center for Structural Biology and Molecular Biophysics, The University of Texas Medical Branch, Galveston, TX 77555, USA
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6
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Liu K, Wu L, Yuan S, Wu M, Xu Y, Sun Q, Li S, Zhao S, Hua T, Liu ZJ. Structural basis of CXC chemokine receptor 2 activation and signalling. Nature 2020; 585:135-140. [PMID: 32610344 DOI: 10.1038/s41586-020-2492-5] [Citation(s) in RCA: 108] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 05/14/2020] [Indexed: 01/25/2023]
Abstract
Chemokines and their receptors mediate cell migration, which influences multiple fundamental biological processes and disease conditions such as inflammation and cancer1. Although ample effort has been invested into the structural investigation of the chemokine receptors and receptor-chemokine recognition2-4, less is known about endogenous chemokine-induced receptor activation and G-protein coupling. Here we present the cryo-electron microscopy structures of interleukin-8 (IL-8, also known as CXCL8)-activated human CXC chemokine receptor 2 (CXCR2) in complex with Gi protein, along with a crystal structure of CXCR2 bound to a designed allosteric antagonist. Our results reveal a unique shallow mode of binding between CXCL8 and CXCR2, and also show the interactions between CXCR2 and Gi protein. Further structural analysis of the inactive and active states of CXCR2 reveals a distinct activation process and the competitive small-molecule antagonism of chemokine receptors. In addition, our results provide insights into how a G-protein-coupled receptor is activated by an endogenous protein molecule, which will assist in the rational development of therapeutics that target the chemokine system for better pharmacological profiles.
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Affiliation(s)
- Kaiwen Liu
- iHuman Institute, ShanghaiTech University, Shanghai, China.,School of Life Science and Technology, ShanghaiTech University, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China.,Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
| | - Lijie Wu
- iHuman Institute, ShanghaiTech University, Shanghai, China
| | - Shuguang Yuan
- The Research Center for Computer-aided Drug Discovery, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Meng Wu
- iHuman Institute, ShanghaiTech University, Shanghai, China.,School of Life Science and Technology, ShanghaiTech University, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Yueming Xu
- iHuman Institute, ShanghaiTech University, Shanghai, China
| | - Qianqian Sun
- iHuman Institute, ShanghaiTech University, Shanghai, China
| | - Shu Li
- The Research Center for Computer-aided Drug Discovery, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Suwen Zhao
- iHuman Institute, ShanghaiTech University, Shanghai, China.,School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Tian Hua
- iHuman Institute, ShanghaiTech University, Shanghai, China.
| | - Zhi-Jie Liu
- iHuman Institute, ShanghaiTech University, Shanghai, China. .,School of Life Science and Technology, ShanghaiTech University, Shanghai, China.
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7
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D'Agostino G, García-Cuesta EM, Gomariz RP, Rodríguez-Frade JM, Mellado M. The multilayered complexity of the chemokine receptor system. Biochem Biophys Res Commun 2020; 528:347-358. [PMID: 32145914 DOI: 10.1016/j.bbrc.2020.02.120] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 02/17/2020] [Accepted: 02/20/2020] [Indexed: 01/08/2023]
Abstract
The chemokines receptor family are membrane-expressed class A-specific seven-transmembrane receptors linked to G proteins. Through interaction with the corresponding ligands, the chemokines, they induce a wide variety of cellular responses including cell polarization, movement, immune and inflammatory responses, as well as the prevention of HIV-1 infection. Like a Russian matryoshka doll, the chemokine receptor system is more complex than initially envisaged. This review focuses on the mechanisms that contribute to this dazzling complexity and how they modulate the signaling events triggered by chemokines. The chemokines and their receptors exist as monomers, dimers and oligomers, their expression pattern is highly regulated, and the ligands can bind distinct receptors with similar affinities. The use of novel imaging-based technologies, particularly real-time imaging modalities, has shed new light on the very dynamic conformations that chemokine receptors adopt depending on the cellular context, and that affect chemokine-mediated responses. This complex scenario presents both challenging and exciting opportunities for drug discovery.
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Affiliation(s)
- Gianluca D'Agostino
- Dept. Immunology and Oncology, Centro Nacional de Biotecnología/CSIC, Darwin 3, Campus Cantoblanco, E-28049, Madrid, Spain
| | - Eva M García-Cuesta
- Dept. Immunology and Oncology, Centro Nacional de Biotecnología/CSIC, Darwin 3, Campus Cantoblanco, E-28049, Madrid, Spain
| | - Rosa P Gomariz
- Dept. Cell Biology, Complutense University of Madrid, Research Institute Hospital 12 de Octubre (i+12), E-28041, Madrid, Spain
| | - José Miguel Rodríguez-Frade
- Dept. Immunology and Oncology, Centro Nacional de Biotecnología/CSIC, Darwin 3, Campus Cantoblanco, E-28049, Madrid, Spain
| | - Mario Mellado
- Dept. Immunology and Oncology, Centro Nacional de Biotecnología/CSIC, Darwin 3, Campus Cantoblanco, E-28049, Madrid, Spain.
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8
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Bhusal RP, Foster SR, Stone MJ. Structural basis of chemokine and receptor interactions: Key regulators of leukocyte recruitment in inflammatory responses. Protein Sci 2019; 29:420-432. [PMID: 31605402 DOI: 10.1002/pro.3744] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 10/03/2019] [Accepted: 10/03/2019] [Indexed: 12/16/2022]
Abstract
In response to infection or injury, the body mounts an inflammatory immune response in order to neutralize pathogens and promote tissue repair. The key effector cells for these responses are the leukocytes (white blood cells), which are specifically recruited to the site of injury. However, dysregulation of the inflammatory response, characterized by the excessive migration of leukocytes to the affected tissues, can also lead to chronic inflammatory diseases. Leukocyte recruitment is regulated by inflammatory mediators, including an important family of small secreted chemokines and their corresponding G protein-coupled receptors expressed in leukocytes. Unsurprisingly, due to their central role in the leukocyte inflammatory response, chemokines and their receptors have been intensely investigated and represent attractive drug targets. Nonetheless, the full therapeutic potential of chemokine receptors has not been realized, largely due to the complexities in the chemokine system. The determination of chemokine-receptor structures in recent years has dramatically shaped our understanding of the molecular mechanisms that underpin chemokine signaling. In this review, we summarize the contemporary structural view of chemokine-receptor recognition, and describe the various binding modes of peptide and small-molecule ligands to chemokine receptors. We also provide some perspectives on the implications of these data for future research and therapeutic development. IMPORTANCE STATEMENT: Given their central role in the leukocyte inflammatory response, chemokines and their receptors are considered as important regulators of physiology and viable therapeutic targets. In this review, we provide a summary of the current understanding of chemokine: chemokine-receptor interactions that have been gained from structural studies, as well as their implications for future drug discovery efforts.
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Affiliation(s)
- Ram Prasad Bhusal
- Infection and Immunity Program, Monash Biomedicine Discovery Institute, and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Simon R Foster
- Infection and Immunity Program, Monash Biomedicine Discovery Institute, and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Martin J Stone
- Infection and Immunity Program, Monash Biomedicine Discovery Institute, and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
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9
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Gangele K, Jamsandekar M, Mishra A, Poluri KM. Unraveling the evolutionary origin of ELR motif using fish CXC chemokine CXCL8. FISH & SHELLFISH IMMUNOLOGY 2019; 93:17-27. [PMID: 31310848 DOI: 10.1016/j.fsi.2019.07.034] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 07/12/2019] [Accepted: 07/12/2019] [Indexed: 05/19/2023]
Abstract
Chemokines are chemotactic proteins involved in host defense through the migration of immune-regulatory cells to the site of infection. Interleukin-8 (CXCL8/IL8) is the most studied "ELR-CXC chemokine/neutrophil activating chemokine (NAC) that regulate neutrophil trafficking during infections and inflammation by binding to its cognate G-protein coupled receptors CXCR1/CXCR2. The "ELR" motif of NAC chemokines is essential for the CXCR1/CXCR2 receptor activation. In order to understand the evolutionary origin of "ELR" motif in the CXC chemokines, a thorough evolutionary study of CXCL8 gene from various fishes and primates was performed. Phylogenetic analysis revealed that the CXCL8 gene can be classified into four distinct lineages (CXCL8-L1a, CXCL8-L1b, CXCL8-L2, and CXCL8-L3), where CXCL8-L1a is the fastest evolving lineage and CXCL8-L3 is the slowest. Selection analysis suggested that The "ELR/DLR" motif containing branches (gadoid and coelacanth) are positively selected. The probable evolutionary trend of "ELR" motif suggested that this motif in ancestor CXCL8 is evolved from the GGR of Lamprey (Agnatha), followed by duplication giving rise to two main motifs in CXCL8 "NXH" in L3 lineage and "ELR/DLR" in L1a/L1b lineages. Although, structural analysis suggested that the overall topology of the CXCL8 proteins is similar, differences do exist at the individual structural elements among the members of different lineages. Functional distance analysis suggested that the CXCL8-L3 lineage is more distant compared to the CXCL8-L1a and L1b lineages from the inferred ancestor. Functional divergence analysis between different lineages suggested that most of the selected residues are important for receptor or glycosaminoglycan binding. Such a functional diversification can be attributed to the novel set of functions adopted by CXCL8 in various species.
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Affiliation(s)
- Krishnakant Gangele
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, 247667, Uttarakhand, India
| | - Minal Jamsandekar
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, 247667, Uttarakhand, India
| | - Amit Mishra
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Jodhpur, 342011, Rajasthan, India
| | - Krishna Mohan Poluri
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, 247667, Uttarakhand, India.
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10
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Jørgensen AS, Larsen O, Uetz-von Allmen E, Lückmann M, Legler DF, Frimurer TM, Veldkamp CT, Hjortø GM, Rosenkilde MM. Biased Signaling of CCL21 and CCL19 Does Not Rely on N-Terminal Differences, but Markedly on the Chemokine Core Domains and Extracellular Loop 2 of CCR7. Front Immunol 2019; 10:2156. [PMID: 31572374 PMCID: PMC6753178 DOI: 10.3389/fimmu.2019.02156] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 08/28/2019] [Indexed: 12/27/2022] Open
Abstract
Chemokine receptors play important roles in the immune system and are linked to several human diseases. Targeting chemokine receptors have so far shown very little success owing to, to some extent, the promiscuity of the immune system and the high degree of biased signaling within it. CCR7 and its two endogenous ligands display biased signaling and here we investigate the differences between the two ligands, CCL21 and CCL19, with respect to their biased activation of CCR7. We use bystander bioluminescence resonance energy transfer (BRET) based signaling assays and Transwell migration assays to determine (A) how swapping of domains between the two ligands affect their signaling patterns and (B) how receptor mutagenesis impacts signaling. Using chimeric ligands we find that the chemokine core domains are central for determining signaling outcome as the lack of β-arrestin-2 recruitment displayed by CCL21 is linked to its core domain and not N-terminus. Through a mutagenesis screen, we identify the extracellular domains of CCR7 to be important for both ligands and show that the two chemokines interact differentially with extracellular loop 2 (ECL-2). By using in silico modeling, we propose a link between ECL-2 interaction and CCR7 signal transduction. Our mutagenesis study also suggests a lysine in the top of TM3, K1303.26, to be important for G protein signaling, but not β-arrestin-2 recruitment. Taken together, the bias in CCR7 between CCL19 and CCL21 relies on the chemokine core domains, where interactions with ECL-2 seem particularly important. Moreover, TM3 selectively regulates G protein signaling as found for other chemokine receptors.
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Affiliation(s)
- Astrid S Jørgensen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Olav Larsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Edith Uetz-von Allmen
- Biotechnology Institute Thurgau (BITg), University of Konstanz, Kreuzlingen, Switzerland
| | - Michael Lückmann
- The Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Daniel F Legler
- Biotechnology Institute Thurgau (BITg), University of Konstanz, Kreuzlingen, Switzerland
| | - Thomas M Frimurer
- The Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Christopher T Veldkamp
- Department of Chemistry, University of Wisconsin-Whitewater, Whitewater, WI, United States
| | - Gertrud M Hjortø
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mette M Rosenkilde
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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11
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Rajarathnam K, Schnoor M, Richardson RM, Rajagopal S. How do chemokines navigate neutrophils to the target site: Dissecting the structural mechanisms and signaling pathways. Cell Signal 2019; 54:69-80. [PMID: 30465827 PMCID: PMC6664297 DOI: 10.1016/j.cellsig.2018.11.004] [Citation(s) in RCA: 147] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 11/07/2018] [Accepted: 11/08/2018] [Indexed: 12/12/2022]
Abstract
Chemokines play crucial roles in combating microbial infection and initiating tissue repair by recruiting neutrophils in a timely and coordinated manner. In humans, no less than seven chemokines (CXCL1, CXCL2, CXCL3, CXCL5, CXCL6, CXCL7, and CXCL8) and two receptors (CXCR1 and CXCR2) mediate neutrophil functions but in a context dependent manner. Neutrophil-activating chemokines reversibly exist as monomers and dimers, and their receptor binding triggers conformational changes that are coupled to G-protein and β-arrestin signaling pathways. G-protein signaling activates a variety of effectors including Ca2+ channels and phospholipase C. β-arrestin serves as a multifunctional adaptor and is coupled to several signaling hubs including MAP kinase and tyrosine kinase pathways. Both G-protein and β-arrestin signaling pathways play important non-overlapping roles in neutrophil trafficking and activation. Functional studies have established many similarities but distinct differences for a given chemokine and between chemokines at the level of monomer vs. dimer, CXCR1 vs. CXCR2 activation, and G-protein vs. β-arrestin pathways. We propose that two forms of the ligand binding two receptors and activating two signaling pathways enables fine-tuned neutrophil function compared to a single form, a single receptor, or a single pathway. We summarize the current knowledge on the molecular mechanisms by which chemokine monomers/dimers activate CXCR1/CXCR2 and how these interactions trigger G-protein/β-arrestin-coupled signaling pathways. We also discuss current challenges and knowledge gaps, and likely advances in the near future that will lead to a better understanding of the relationship between the chemokine-CXCR1/CXCR2-G-protein/β-arrestin axis and neutrophil function.
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Affiliation(s)
- Krishna Rajarathnam
- Department of Biochemistry and Molecular Biology, Department of Microbiology and Immunology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX, USA.
| | - Michael Schnoor
- Department for Molecular Biomedicine, Cinvestav-IPN, 07360 Mexico City, Mexico
| | - Ricardo M Richardson
- Julius L. Chambers Biomedical/Biotechnology Research Institute, North Carolina Central University, Durham, NC 27707, USA
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12
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Joseph PRB, Spyracopoulos L, Rajarathnam K. Dynamics-Derived Insights into Complex Formation between the CXCL8 Monomer and CXCR1 N-Terminal Domain: An NMR Study. Molecules 2018; 23:E2825. [PMID: 30384436 PMCID: PMC6278376 DOI: 10.3390/molecules23112825] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 10/19/2018] [Accepted: 10/25/2018] [Indexed: 11/29/2022] Open
Abstract
Interleukin-8 (CXCL8), a potent neutrophil-activating chemokine, exerts its function by activating the CXCR1 receptor that belongs to class A G protein-coupled receptors (GPCRs). Receptor activation involves interactions between the CXCL8 N-terminal loop and CXCR1 N-terminal domain (N-domain) residues (Site-I) and between the CXCL8 N-terminal and CXCR1 extracellular/transmembrane residues (Site-II). CXCL8 exists in equilibrium between monomers and dimers, and it is known that the monomer binds CXCR1 with much higher affinity and that Site-I interactions are largely responsible for the differences in monomer vs. dimer affinity. Here, using backbone 15N-relaxation nuclear magnetic resonance (NMR) data, we characterized the dynamic properties of the CXCL8 monomer and the CXCR1 N-domain in the free and bound states. The main chain of CXCL8 appears largely rigid on the picosecond time scale as evident from high order parameters (S²). However, on average, S² are higher in the bound state. Interestingly, several residues show millisecond-microsecond (ms-μs) dynamics only in the bound state. The CXCR1 N-domain is unstructured in the free state but structured with significant dynamics in the bound state. Isothermal titration calorimetry (ITC) data indicate that both enthalpic and entropic factors contribute to affinity, suggesting that increased slow dynamics in the bound state contribute to affinity. In sum, our data indicate a critical and complex role for dynamics in driving CXCL8 monomer-CXCR1 Site-I interactions.
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Affiliation(s)
- Prem Raj B Joseph
- Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, TX 77555, USA.
- Sealy Center for Structural Biology and Molecular Biophysics, The University of Texas Medical Branch, Galveston, TX 77555, USA.
| | - Leo Spyracopoulos
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada.
| | - Krishna Rajarathnam
- Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, TX 77555, USA.
- Sealy Center for Structural Biology and Molecular Biophysics, The University of Texas Medical Branch, Galveston, TX 77555, USA.
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13
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Rajarathnam K, Sepuru KM, Joseph PRB, Sawant KV, Brown AJ. Glycosaminoglycan Interactions Fine-Tune Chemokine-Mediated Neutrophil Trafficking: Structural Insights and Molecular Mechanisms. J Histochem Cytochem 2018; 66:229-239. [PMID: 29290145 PMCID: PMC5958375 DOI: 10.1369/0022155417739864] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 10/10/2017] [Indexed: 01/01/2023] Open
Abstract
Circulating neutrophils, rapidly recruited in response to microbial infection, form the first line in host defense. Humans express ~50 chemokines, of which a subset of seven chemokines, characterized by the conserved "Glu-Leu-Arg" motif, mediate neutrophil recruitment. Neutrophil-activating chemokines (NACs) share similar structures, exist as monomers and dimers, activate the CXCR2 receptor on neutrophils, and interact with tissue glycosaminoglycans (GAGs). Considering cellular assays have shown that NACs have similar CXCR2 activity, the question has been and remains, why do humans express so many NACs? In this review, we make the case that NACs are not redundant and that distinct GAG interactions determine chemokine-specific in vivo functions. Structural studies have shown that the GAG-binding interactions of NACs are distinctly different, and that conserved and specific residues in the context of structure determine geometries that could not have been predicted from sequences alone. Animal studies indicate recruitment profiles of monomers and dimers are distinctly different, monomer-dimer equilibrium regulates recruitment, and that recruitment profiles vary between chemokines and between tissues, providing evidence that GAG interactions orchestrate neutrophil recruitment. We propose in vivo GAG interactions impact several chemokine properties including gradients and lifetime, and that these interactions fine-tune and define the functional response of each chemokine that can vary between different cell and tissue types for successful resolution of inflammation.
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Affiliation(s)
- Krishna Rajarathnam
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas
- Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, Texas
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas
| | - Krishna Mohan Sepuru
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas
- Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, Texas
| | - Prem Raj B Joseph
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas
- Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, Texas
| | - Kirti V Sawant
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas
- Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, Texas
| | - Aaron J Brown
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas
- Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, Texas
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14
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Sadat Mohajer F, Parvizpour S, Razmara J, Shahir Shamsir M. The two mutations of actin-myosin interface and their effect on the dynamics, structures, and functions of skeletal muscle actin. J Biomol Struct Dyn 2018; 37:372-382. [PMID: 29338614 DOI: 10.1080/07391102.2018.1427630] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Congenital myopathy is a broad category of muscular diseases with symptoms appearing at the time of birth. One type of congenital myopathy is Congenital Fiber Type Disproportion (CFTD), a severely debilitating disease. The G48D and G48C mutations in the D-loop and the actin-myosin interface are the two causes of CFTD. These mutations have been shown to significantly affect the structure and function of muscle fibers. To the author's knowledge, the effects of these mutations have not yet been studied. In this work, the power stroke structure of the head domain of myosin and the wild and mutated types of actin were modeled. Then, a MD simulation was run for the modeled structures to study the effects of these mutations on the structure, function, and molecular dynamics of actin. The wild and mutated actins docked with myosin showed differences in hydrogen bonding patterns, free binding energies, and hydrogen bond occupation frequencies. The G48D and G48C mutations significantly impacted the conformation of D-loops because of their larger size compared to Glycine and their ability to interfere with the polarity or hydrophobicity of this neutralized and hydrophobic loop. Therefore, the mutated loops were unable to fit properly into the hydrophobic groove of the adjacent G-actin. The abnormal structure of D-loops seems to result in the abnormal assembly of F-actins, giving rise to the symptoms of CFTD. It was also noted that G48C and G48D did not form hydrogen bonds with myosin in the residue 48 location. Nevertheless, in this case, muscles are unable to contract properly due to muscle atrophy.
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Affiliation(s)
- Faeze Sadat Mohajer
- a Bioinformatics Research Group, Faculty of Bioscience and Medical Engineering , UniversitiTeknologi Malaysia , Johor Bahru , Malaysia
| | - Sepideh Parvizpour
- b Research Center for Pharmaceutical Nanotechnology, Biomedicine Institute , Tabriz University of Medical Sciences , Tabriz , Iran
| | - Jafar Razmara
- c Departement of Computer Science , University of Tabriz , Tabriz , Iran
| | - Mohd Shahir Shamsir
- a Bioinformatics Research Group, Faculty of Bioscience and Medical Engineering , UniversitiTeknologi Malaysia , Johor Bahru , Malaysia
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15
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von Hundelshausen P, Agten SM, Eckardt V, Blanchet X, Schmitt MM, Ippel H, Neideck C, Bidzhekov K, Leberzammer J, Wichapong K, Faussner A, Drechsler M, Grommes J, van Geffen JP, Li H, Ortega-Gomez A, Megens RTA, Naumann R, Dijkgraaf I, Nicolaes GAF, Döring Y, Soehnlein O, Lutgens E, Heemskerk JWM, Koenen RR, Mayo KH, Hackeng TM, Weber C. Chemokine interactome mapping enables tailored intervention in acute and chronic inflammation. Sci Transl Med 2017; 9:9/384/eaah6650. [PMID: 28381538 DOI: 10.1126/scitranslmed.aah6650] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 01/18/2017] [Accepted: 03/01/2017] [Indexed: 12/21/2022]
Abstract
Chemokines orchestrate leukocyte trafficking and function in health and disease. Heterophilic interactions between chemokines in a given microenvironment may amplify, inhibit, or modulate their activity; however, a systematic evaluation of the chemokine interactome has not been performed. We used immunoligand blotting and surface plasmon resonance to obtain a comprehensive map of chemokine-chemokine interactions and to confirm their specificity. Structure-function analyses revealed that chemokine activity can be enhanced by CC-type heterodimers but inhibited by CXC-type heterodimers. Functional synergism was achieved through receptor heteromerization induced by CCL5-CCL17 or receptor retention at the cell surface via auxiliary proteoglycan binding of CCL5-CXCL4. In contrast, inhibitory activity relied on conformational changes (in CXCL12), affecting receptor signaling. Obligate CC-type heterodimers showed high efficacy and potency and drove acute lung injury and atherosclerosis, processes abrogated by specific CCL5-derived peptide inhibitors or knock-in of an interaction-deficient CXCL4 variant. Atheroprotective effects of CCL17 deficiency were phenocopied by a CCL5-derived peptide disrupting CCL5-CCL17 heterodimers, whereas a CCL5 α-helix peptide mimicked inhibitory effects on CXCL12-driven platelet aggregation. Thus, formation of specific chemokine heterodimers differentially dictates functional activity and can be exploited for therapeutic targeting.
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Affiliation(s)
- Philipp von Hundelshausen
- Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-Universität München, Munich, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Munich Heart Alliance, Munich, Germany
| | - Stijn M Agten
- Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, Netherlands
| | - Veit Eckardt
- Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-Universität München, Munich, Germany
| | - Xavier Blanchet
- Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-Universität München, Munich, Germany
| | - Martin M Schmitt
- Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-Universität München, Munich, Germany
| | - Hans Ippel
- Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, Netherlands
| | - Carlos Neideck
- Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-Universität München, Munich, Germany
| | - Kiril Bidzhekov
- Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-Universität München, Munich, Germany
| | - Julian Leberzammer
- Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-Universität München, Munich, Germany
| | - Kanin Wichapong
- Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, Netherlands
| | - Alexander Faussner
- Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-Universität München, Munich, Germany
| | - Maik Drechsler
- Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-Universität München, Munich, Germany
| | - Jochen Grommes
- Department of Vascular Surgery, RWTH Aachen University, Aachen, Germany
| | - Johanna P van Geffen
- Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, Netherlands
| | - He Li
- Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-Universität München, Munich, Germany
| | - Almudena Ortega-Gomez
- Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-Universität München, Munich, Germany
| | - Remco T A Megens
- Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-Universität München, Munich, Germany
| | - Ronald Naumann
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Ingrid Dijkgraaf
- Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, Netherlands
| | - Gerry A F Nicolaes
- Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, Netherlands
| | - Yvonne Döring
- Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-Universität München, Munich, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Munich Heart Alliance, Munich, Germany
| | - Oliver Soehnlein
- Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-Universität München, Munich, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Munich Heart Alliance, Munich, Germany.,Department of Physiology and Pharmacology, Karolinksa Institutet, Stockholm, Sweden
| | - Esther Lutgens
- Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-Universität München, Munich, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Munich Heart Alliance, Munich, Germany.,Department of Medical Biochemistry, AMC, Amsterdam, Netherlands
| | - Johan W M Heemskerk
- German Center for Cardiovascular Research (DZHK), Partner Site Munich Heart Alliance, Munich, Germany
| | - Rory R Koenen
- Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-Universität München, Munich, Germany.,Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, Netherlands
| | - Kevin H Mayo
- Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, Netherlands.,Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Tilman M Hackeng
- Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, Netherlands
| | - Christian Weber
- Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-Universität München, Munich, Germany. .,German Center for Cardiovascular Research (DZHK), Partner Site Munich Heart Alliance, Munich, Germany.,Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, Netherlands
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16
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Brown AJ, Sepuru KM, Sawant KV, Rajarathnam K. Platelet-Derived Chemokine CXCL7 Dimer Preferentially Exists in the Glycosaminoglycan-Bound Form: Implications for Neutrophil-Platelet Crosstalk. Front Immunol 2017; 8:1248. [PMID: 29038657 PMCID: PMC5630695 DOI: 10.3389/fimmu.2017.01248] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Accepted: 09/20/2017] [Indexed: 11/25/2022] Open
Abstract
Platelet-derived chemokine CXCL7 (also known as NAP-2) plays a crucial role in orchestrating neutrophil recruitment in response to vascular injury. CXCL7 exerts its function by activating the CXC chemokine receptor 2 (CXCR2) receptor and binding sulfated glycosaminoglycans (GAGs) that regulate receptor activity. CXCL7 exists as monomers, dimers, and tetramers, and previous studies have shown that the monomer dominates at lower and the tetramer at higher concentrations. These observations then raise the question: what, if any, is the role of the dimer? In this study, we make a compelling observation that the dimer is actually the favored form in the GAG-bound state. Further, we successfully characterized the structural basis of dimer binding to GAG heparin using solution nuclear magnetic resonance (NMR) spectroscopy. The chemical shift assignments were obtained by exploiting heparin binding-induced NMR spectral changes in the WT monomer and dimer and also using a disulfide-linked obligate dimer. We observe that the receptor interactions of the dimer are similar to the monomer and that heparin-bound dimer is occluded from receptor interactions. Cellular assays also show that the heparin-bound CXCL7 is impaired for CXCR2 activity. We conclude that the dimer–GAG interactions play an important role in neutrophil–platelet crosstalk, and that these interactions regulate gradient formation and the availability of the free monomer for CXCR2 activation and intrathrombus neutrophil migration to the injury site.
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Affiliation(s)
- Aaron J Brown
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, United States.,Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX, United States
| | - Krishna Mohan Sepuru
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, United States.,Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX, United States
| | - Kirti V Sawant
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, United States
| | - Krishna Rajarathnam
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, United States.,Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX, United States.,Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, United States
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17
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Powell D, Tauzin S, Hind LE, Deng Q, Beebe DJ, Huttenlocher A. Chemokine Signaling and the Regulation of Bidirectional Leukocyte Migration in Interstitial Tissues. Cell Rep 2017; 19:1572-1585. [PMID: 28538177 PMCID: PMC5505660 DOI: 10.1016/j.celrep.2017.04.078] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 03/17/2017] [Accepted: 04/28/2017] [Indexed: 01/02/2023] Open
Abstract
Motile cells navigate through complex tissue environments that include both attractive and repulsive cues. In response to tissue wounding, neutrophils, primary cells of the innate immune response, exhibit bidirectional migration that is orchestrated by chemokines and their receptors. Although progress has been made in identifying signals that mediate the recruitment phase, the mechanisms that regulate neutrophil reverse migration remain largely unknown. Here, we visualize bidirectional neutrophil migration to sterile wounds in zebrafish larvae and identify specific roles for the chemokine receptors Cxcr1 and Cxcr2 in neutrophil recruitment to sterile injury and infection. Notably, we also identify Cxcl8a/Cxcr2 as a specific ligand-receptor pair that orchestrates neutrophil chemokinesis in interstitial tissues during neutrophil reverse migration and resolution of inflammation. Taken together, our findings identify distinct receptors that mediate bidirectional leukocyte motility during interstitial migration depending on the context and type of tissue damage in vivo.
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Affiliation(s)
- Davalyn Powell
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Sebastien Tauzin
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Laurel E Hind
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Qing Deng
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - David J Beebe
- Department of Biomedical Engineering and University of Wisconsin Carbone Cancer Center, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Anna Huttenlocher
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI 53706, USA; Department of Pediatrics, University of Wisconsin-Madison, Madison, WI 53706, USA.
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18
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Brown AJ, Sepuru KM, Rajarathnam K. Structural Basis of Native CXCL7 Monomer Binding to CXCR2 Receptor N-Domain and Glycosaminoglycan Heparin. Int J Mol Sci 2017; 18:ijms18030508. [PMID: 28245630 PMCID: PMC5372524 DOI: 10.3390/ijms18030508] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 02/14/2017] [Accepted: 02/21/2017] [Indexed: 11/23/2022] Open
Abstract
CXCL7, a chemokine highly expressed in platelets, orchestrates neutrophil recruitment during thrombosis and related pathophysiological processes by interacting with CXCR2 receptor and sulfated glycosaminoglycans (GAG). CXCL7 exists as monomers and dimers, and dimerization (~50 μM) and CXCR2 binding (~10 nM) constants indicate that CXCL7 is a potent agonist as a monomer. Currently, nothing is known regarding the structural basis by which receptor and GAG interactions mediate CXCL7 function. Using solution nuclear magnetic resonance (NMR) spectroscopy, we characterized the binding of CXCL7 monomer to the CXCR2 N-terminal domain (CXCR2Nd) that constitutes a critical docking site and to GAG heparin. We found that CXCR2Nd binds a hydrophobic groove and that ionic interactions also play a role in mediating binding. Heparin binds a set of contiguous basic residues indicating a prominent role for ionic interactions. Modeling studies reveal that the binding interface is dynamic and that GAG adopts different binding geometries. Most importantly, several residues involved in GAG binding are also involved in receptor interactions, suggesting that GAG-bound monomer cannot activate the receptor. Further, this is the first study that describes the structural basis of receptor and GAG interactions of a native monomer of the neutrophil-activating chemokine family.
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Affiliation(s)
- Aaron J Brown
- Department of Biochemistry and Molecular Biology, and Sealy Center for Structural Biology and Molecular Biophysics, The University of Texas Medical Branch, Galveston, TX 77555, USA.
| | - Krishna Mohan Sepuru
- Department of Biochemistry and Molecular Biology, and Sealy Center for Structural Biology and Molecular Biophysics, The University of Texas Medical Branch, Galveston, TX 77555, USA.
| | - Krishna Rajarathnam
- Department of Biochemistry and Molecular Biology, and Sealy Center for Structural Biology and Molecular Biophysics, The University of Texas Medical Branch, Galveston, TX 77555, USA.
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19
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Kleist AB, Getschman AE, Ziarek JJ, Nevins AM, Gauthier PA, Chevigné A, Szpakowska M, Volkman BF. New paradigms in chemokine receptor signal transduction: Moving beyond the two-site model. Biochem Pharmacol 2016; 114:53-68. [PMID: 27106080 DOI: 10.1016/j.bcp.2016.04.007] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 04/13/2016] [Indexed: 10/21/2022]
Abstract
Chemokine receptor (CKR) signaling forms the basis of essential immune cellular functions, and dysregulated CKR signaling underpins numerous disease processes of the immune system and beyond. CKRs, which belong to the seven transmembrane domain receptor (7TMR) superfamily, initiate signaling upon binding of endogenous, secreted chemokine ligands. Chemokine-CKR interactions are traditionally described by a two-step/two-site mechanism, in which the CKR N-terminus recognizes the chemokine globular core (i.e. site 1 interaction), followed by activation when the unstructured chemokine N-terminus is inserted into the receptor TM bundle (i.e. site 2 interaction). Several recent studies challenge the structural independence of sites 1 and 2 by demonstrating physical and allosteric links between these supposedly separate sites. Others contest the functional independence of these sites, identifying nuanced roles for site 1 and other interactions in CKR activation. These developments emerge within a rapidly changing landscape in which CKR signaling is influenced by receptor PTMs, chemokine and CKR dimerization, and endogenous non-chemokine ligands. Simultaneous advances in the structural and functional characterization of 7TMR biased signaling have altered how we understand promiscuous chemokine-CKR interactions. In this review, we explore new paradigms in CKR signal transduction by considering studies that depict a more intricate architecture governing the consequences of chemokine-CKR interactions.
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Affiliation(s)
- Andrew B Kleist
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
| | - Anthony E Getschman
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
| | - Joshua J Ziarek
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Ave, Boston, MA 02115, USA.
| | - Amanda M Nevins
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
| | - Pierre-Arnaud Gauthier
- Department of Infection and Immunity, Luxembourg Institute of Health, L-4354 Esch-sur-Alzette, Luxembourg.
| | - Andy Chevigné
- Department of Infection and Immunity, Luxembourg Institute of Health, L-4354 Esch-sur-Alzette, Luxembourg.
| | - Martyna Szpakowska
- Department of Infection and Immunity, Luxembourg Institute of Health, L-4354 Esch-sur-Alzette, Luxembourg.
| | - Brian F Volkman
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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20
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Sepuru KM, Rajarathnam K. CXCL1/MGSA Is a Novel Glycosaminoglycan (GAG)-binding Chemokine: STRUCTURAL EVIDENCE FOR TWO DISTINCT NON-OVERLAPPING BINDING DOMAINS. J Biol Chem 2015; 291:4247-55. [PMID: 26721883 DOI: 10.1074/jbc.m115.697888] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Indexed: 12/12/2022] Open
Abstract
In humans, the chemokine CXCL1/MGSA (hCXCL1) plays fundamental and diverse roles in pathophysiology, from microbial killing to cancer progression, by orchestrating the directed migration of immune and non-immune cells. Cellular trafficking is highly regulated and requires concentration gradients that are achieved by interactions with sulfated glycosaminoglycans (GAGs). However, very little is known regarding the structural basis underlying hCXCL1-GAG interactions. We addressed this by characterizing the binding of GAG heparin oligosaccharides to hCXCL1 using NMR spectroscopy. Binding experiments under conditions at which hCXCL1 exists as monomers and dimers indicate that the dimer is the high-affinity GAG ligand. NMR experiments and modeling studies indicate that lysine and arginine residues mediate binding and that they are located in two non-overlapping domains. One domain, consisting of N-loop and C-helical residues (defined as α-domain) has also been identified previously as the GAG-binding domain for the related chemokine CXCL8/IL-8. The second domain, consisting of residues from the N terminus, 40s turn, and third β-strand (defined as β-domain) is novel. Eliminating β-domain binding by mutagenesis does not perturb α-domain binding, indicating two independent GAG-binding sites. It is known that N-loop and N-terminal residues mediate receptor activation, and we show that these residues are also involved in extensive GAG interactions. We also show that the GAG-bound hCXCL1 completely occlude receptor binding. We conclude that hCXCL1-GAG interactions provide stringent control over regulating chemokine levels and receptor accessibility and activation, and that chemotactic gradients mediate cellular trafficking to the target site.
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Affiliation(s)
- Krishna Mohan Sepuru
- From the Department of Biochemistry and Molecular Biology and Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, Texas 77555
| | - Krishna Rajarathnam
- From the Department of Biochemistry and Molecular Biology and Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, Texas 77555
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21
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Herring CA, Singer CM, Ermakova EA, Khairutdinov BI, Zuev YF, Jacobs DJ, Nesmelova IV. Dynamics and thermodynamic properties of CXCL7 chemokine. Proteins 2015; 83:1987-2007. [PMID: 26297927 DOI: 10.1002/prot.24913] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Revised: 08/05/2015] [Accepted: 08/18/2015] [Indexed: 11/09/2022]
Abstract
Chemokines form a family of signaling proteins mainly responsible for directing the traffic of leukocytes, where their biological activity can be modulated by their oligomerization state. We characterize the dynamics and thermodynamic stability of monomer and homodimer structures of CXCL7, one of the most abundant platelet chemokines, using experimental methods that include circular dichroism (CD) and nuclear magnetic resonance (NMR) spectroscopy, and computational methods that include the anisotropic network model (ANM), molecular dynamics (MD) simulations and the distance constraint model (DCM). A consistent picture emerges for the effects of dimerization and Cys5-Cys31 and Cys7-Cys47 disulfide bonds formation. The presence of disulfide bonds is not critical for maintaining structural stability in the monomer or dimer, but the monomer is destabilized more than the dimer upon removal of disulfide bonds. Disulfide bonds play a key role in shaping the characteristics of native state dynamics. The combined analysis shows that upon dimerization flexibly correlated motions are induced between the 30s and 50s loop within each monomer and across the dimer interface. Interestingly, the greatest gain in flexibility upon dimerization occurs when both disulfide bonds are present, and the homodimer is least stable relative to its two monomers. These results suggest that the highly conserved disulfide bonds in chemokines facilitate a structural mechanism that is tuned to optimally distinguish functional characteristics between monomer and dimer.
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Affiliation(s)
- Charles A Herring
- Department of Physics and Optical Science, University of North Carolina, Charlotte, North Carolina, 28223
| | - Christopher M Singer
- Department of Physics and Optical Science, University of North Carolina, Charlotte, North Carolina, 28223
| | - Elena A Ermakova
- Kazan Institute of Biochemistry and Biophysics, Kazan, 40111, Russia
| | | | - Yuriy F Zuev
- Kazan Institute of Biochemistry and Biophysics, Kazan, 40111, Russia
| | - Donald J Jacobs
- Department of Physics and Optical Science, University of North Carolina, Charlotte, North Carolina, 28223.,Center for Biomedical Engineering, University of North Carolina, Charlotte, North Carolina, 28223
| | - Irina V Nesmelova
- Department of Physics and Optical Science, University of North Carolina, Charlotte, North Carolina, 28223.,Center for Biomedical Engineering, University of North Carolina, Charlotte, North Carolina, 28223
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Characterization of G protein coupling mediated by the conserved D134(3.49) of DRY motif, M241(6.34), and F251(6.44) residues on human CXCR1. FEBS Open Bio 2015; 5:182-90. [PMID: 25834784 PMCID: PMC4372616 DOI: 10.1016/j.fob.2015.03.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 02/27/2015] [Accepted: 03/03/2015] [Indexed: 01/01/2023] Open
Abstract
Mutations in the DRY motif of CXCR1 abolish ligand binding and receptor activation. Point mutations between TM6 and i3 loop result in constitutive activity of CXCR1. Constitutive activity of mutant CXCR1 occurs via Gα15 signaling activation. The highly conserved DRY motifs have distinct roles in CXCR1 and CXCR2.
CXCR1, a receptor for interleukin-8 (IL-8), plays an important role in defending against pathogen invasion during neutrophil-mediated innate immune response. Human CXCR1 is a G protein-coupled receptor (GPCR) with its characteristic seven transmembrane domains (TMs). Functional and structural analyses of several GPCRs have revealed that conserved residues on TM3 (including the highly conserved Asp-Arg-Tyr (DRY) motif) and TM6 near intracellular loops contain domains critical for G protein coupling as well as GPCR activation. The objective of this study was to elucidate the role of critical amino acid residues on TM3 near intracellular loop 2 (i2) and TM6 near intracellular loop 3 (i3), including S1323.47 (Baldwin location), D1343.49, M2416.34, and F2516.44, in G protein coupling and CXCR1 activation. The results demonstrate that mutations of D1343.49 at DRY motif of CXCR1 (D134N and D134V) completely abolished the ligand binding and functional response of the receptor. Additionally, point mutations at positions 241 and 251 between TM6 and i3 loop generated mutant receptors with modest constitutive activity via Gα15 signaling activation. Our results show that D1343.49 on the highly conserved DRY motif has a distinct role for CXCR1 compared to its homologues (CXCR2 and KSHV-GPCR) in G protein coupling and receptor activation. In addition, M2416.34 and F2516.44 along with our previously identified V2476.40 on TM6 are spatially located in a “hot spot” likely essential for CXCR1 activation. Identification of these amino acid residues may be useful for elucidating mechanism of CXCR1 activation and designing specific antagonists for the treatment of CXCR1-mediated diseases.
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Key Words
- CXCR1
- CXCR1, CXC receptor 1
- Chemokine receptor
- Constitutive activity
- DRY motif, Asp-Arg-Tyr motif
- G protein coupled receptor
- GPCR, G protein-coupled receptor
- Gα15
- Gαi
- IL-8, interleukin 8
- IP, inositol phosphate
- Kd, affinity constants
- PLC, phospholipase C
- PTX, pertussis toxin
- TMs, transmembrane domain
- WT, wild type
- i2, intracellular loop 2
- i3, intracellular loop 3
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Joseph PRB, Rajarathnam K. Solution NMR characterization of WT CXCL8 monomer and dimer binding to CXCR1 N-terminal domain. Protein Sci 2014; 24:81-92. [PMID: 25327289 DOI: 10.1002/pro.2590] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 09/03/2014] [Accepted: 10/10/2014] [Indexed: 01/24/2023]
Abstract
Chemokine CXCL8 and its receptor CXCR1 are key mediators in combating infection and have also been implicated in the pathophysiology of various diseases including chronic obstructive pulmonary disease (COPD) and cancer. CXCL8 exists as monomers and dimers but monomer alone binds CXCR1 with high affinity. CXCL8 function involves binding two distinct CXCR1 sites - the N-terminal domain (Site-I) and the extracellular/transmembrane domain (Site-II). Therefore, higher monomer affinity could be due to stronger binding at Site-I or Site-II or both. We have now characterized the binding of a human CXCR1 N-terminal domain peptide (hCXCR1Ndp) to WT CXCL8 under conditions where it exists as both monomers and dimers. We show that the WT monomer binds the CXCR1 N-domain with much higher affinity and that binding is coupled to dimer dissociation. We also characterized the binding of two CXCL8 monomer variants and a trapped dimer to two different hCXCR1Ndp constructs, and observe that the monomer binds with ∼10- to 100-fold higher affinity than the dimer. Our studies also show that the binding constants of monomer and dimer to the receptor peptides, and the dimer dissociation constant, can vary significantly as a function of pH and buffer, and so the ability to observe WT monomer peaks is critically dependent on NMR experimental conditions. We conclude that the monomer is the high affinity CXCR1 agonist, that Site-I interactions play a dominant role in determining monomer vs. dimer affinity, and that the dimer plays an indirect role in regulating monomer function.
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Affiliation(s)
- Prem Raj B Joseph
- Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, Texas, 77555
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Sepuru KM, Poluri KM, Rajarathnam K. Solution structure of CXCL5--a novel chemokine and adipokine implicated in inflammation and obesity. PLoS One 2014; 9:e93228. [PMID: 24695525 PMCID: PMC3973705 DOI: 10.1371/journal.pone.0093228] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 03/01/2014] [Indexed: 11/19/2022] Open
Abstract
The chemokine CXCL5 is selectively expressed in highly specialized cells such as epithelial type II cells in the lung and white adipose tissue macrophages in muscle, where it mediates diverse functions from combating microbial infections by regulating neutrophil trafficking to promoting obesity by inhibiting insulin signaling. Currently very little is known regarding the structural basis of how CXCL5 mediates its novel functions. Towards this missing knowledge, we have solved the solution structure of the CXCL5 dimer by NMR spectroscopy. CXCL5 is a member of a subset of seven CXCR2-activating chemokines (CAC) that are characterized by the highly conserved ELR motif in the N-terminal tail. The structure shows that CXCL5 adopts the typical chemokine fold, but also reveals several distinct differences in the 30 s loop and N-terminal residues; not surprisingly, crosstalk between N-terminal and 30 s loop residues have been implicated as a major determinant of receptor activity. CAC function also involves binding to highly sulfated glycosaminoglycans (GAG), and the CXCL5 structure reveals a distinct distribution of positively charged residues, suggesting that differences in GAG interactions also influence function. The availability of the structure should now facilitate the design of experiments to better understand the molecular basis of various CXCL5 functions, and also serve as a template for the design of inhibitors for use in a clinical setting.
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Affiliation(s)
- Krishna Mohan Sepuru
- Department of Biochemistry & Molecular Biology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Krishna Mohan Poluri
- Department of Biochemistry & Molecular Biology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Krishna Rajarathnam
- Department of Biochemistry & Molecular Biology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, Texas, United States of America
- * E-mail:
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