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García-Cuesta EM, Martínez P, Selvaraju K, Ulltjärn G, Gómez Pozo AM, D'Agostino G, Gardeta S, Quijada-Freire A, Blanco Gabella P, Roca C, Hoyo DD, Jiménez-Saiz R, García-Rubia A, Soler Palacios B, Lucas P, Ayala-Bueno R, Santander Acerete N, Carrasco Y, Oscar Sorzano C, Martinez A, Campillo NE, Jensen LD, Rodriguez Frade JM, Santiago C, Mellado M. Allosteric modulation of the CXCR4:CXCL12 axis by targeting receptor nanoclustering via the TMV-TMVI domain. eLife 2024; 13:RP93968. [PMID: 39248648 PMCID: PMC11383527 DOI: 10.7554/elife.93968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/10/2024] Open
Abstract
CXCR4 is a ubiquitously expressed chemokine receptor that regulates leukocyte trafficking and arrest in both homeostatic and pathological states. It also participates in organogenesis, HIV-1 infection, and tumor development. Despite the potential therapeutic benefit of CXCR4 antagonists, only one, plerixafor (AMD3100), which blocks the ligand-binding site, has reached the clinic. Recent advances in imaging and biophysical techniques have provided a richer understanding of the membrane organization and dynamics of this receptor. Activation of CXCR4 by CXCL12 reduces the number of CXCR4 monomers/dimers at the cell membrane and increases the formation of large nanoclusters, which are largely immobile and are required for correct cell orientation to chemoattractant gradients. Mechanistically, CXCR4 activation involves a structural motif defined by residues in TMV and TMVI. Using this structural motif as a template, we performed in silico molecular modeling followed by in vitro screening of a small compound library to identify negative allosteric modulators of CXCR4 that do not affect CXCL12 binding. We identified AGR1.137, a small molecule that abolishes CXCL12-mediated receptor nanoclustering and dynamics and blocks the ability of cells to sense CXCL12 gradients both in vitro and in vivo while preserving ligand binding and receptor internalization.
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Affiliation(s)
- Eva M García-Cuesta
- Chemokine Signaling group, Department of Immunology and Oncology, Centro Nacional de Biotecnología/CSIC, Campus de Cantoblanco, Madrid, Spain
| | - Pablo Martínez
- Chemokine Signaling group, Department of Immunology and Oncology, Centro Nacional de Biotecnología/CSIC, Campus de Cantoblanco, Madrid, Spain
| | - Karthik Selvaraju
- Division of Diagnostics and Specialist Medicine, Department of Health, Medical and Caring Sciences, Linköping University, Linköping, Sweden
| | - Gabriel Ulltjärn
- Division of Diagnostics and Specialist Medicine, Department of Health, Medical and Caring Sciences, Linköping University, Linköping, Sweden
| | | | - Gianluca D'Agostino
- Chemokine Signaling group, Department of Immunology and Oncology, Centro Nacional de Biotecnología/CSIC, Campus de Cantoblanco, Madrid, Spain
| | - Sofia Gardeta
- Chemokine Signaling group, Department of Immunology and Oncology, Centro Nacional de Biotecnología/CSIC, Campus de Cantoblanco, Madrid, Spain
| | - Adriana Quijada-Freire
- Chemokine Signaling group, Department of Immunology and Oncology, Centro Nacional de Biotecnología/CSIC, Campus de Cantoblanco, Madrid, Spain
| | | | - Carlos Roca
- Centro de Investigaciones Biológicas Margarita Salas (CIB-CSIC), Madrid, Spain
| | - Daniel Del Hoyo
- Biocomputing Unit, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, Madrid, Spain
| | - Rodrigo Jiménez-Saiz
- Chemokine Signaling group, Department of Immunology and Oncology, Centro Nacional de Biotecnología/CSIC, Campus de Cantoblanco, Madrid, Spain
- Department of Immunology, Instituto de Investigación Sanitaria Hospital Universitario de La Princesa (IIS-Princesa), Madrid, Spain
- Department of Medicine, McMaster Immunology Research Centre (MIRC), Schroeder Allergy and Immunology Research Institute, McMaster University, Hamilton, Canada
- Faculty of Experimental Sciences, Universidad Francisco de Vitoria (UFV), Madrid, Spain
| | | | - Blanca Soler Palacios
- Chemokine Signaling group, Department of Immunology and Oncology, Centro Nacional de Biotecnología/CSIC, Campus de Cantoblanco, Madrid, Spain
| | - Pilar Lucas
- Chemokine Signaling group, Department of Immunology and Oncology, Centro Nacional de Biotecnología/CSIC, Campus de Cantoblanco, Madrid, Spain
| | - Rosa Ayala-Bueno
- Chemokine Signaling group, Department of Immunology and Oncology, Centro Nacional de Biotecnología/CSIC, Campus de Cantoblanco, Madrid, Spain
| | - Noelia Santander Acerete
- Chemokine Signaling group, Department of Immunology and Oncology, Centro Nacional de Biotecnología/CSIC, Campus de Cantoblanco, Madrid, Spain
| | - Yolanda Carrasco
- B Lymphocyte Dynamics, Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB)/CSIC, Campus de Cantoblanco, Madrid, Spain
| | - Carlos Oscar Sorzano
- Biocomputing Unit, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, Madrid, Spain
| | - Ana Martinez
- Centro de Investigaciones Biológicas Margarita Salas (CIB-CSIC), Madrid, Spain
- Neurodegenerative Diseases Biomedical Research Network Center (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Nuria E Campillo
- Centro de Investigaciones Biológicas Margarita Salas (CIB-CSIC), Madrid, Spain
| | - Lasse D Jensen
- Division of Diagnostics and Specialist Medicine, Department of Health, Medical and Caring Sciences, Linköping University, Linköping, Sweden
| | - Jose Miguel Rodriguez Frade
- Chemokine Signaling group, Department of Immunology and Oncology, Centro Nacional de Biotecnología/CSIC, Campus de Cantoblanco, Madrid, Spain
| | - César Santiago
- X-ray Crystallography Unit, Department of Macromolecules Structure, Centro Nacional de Biotecnología/CSIC, Campus de Cantoblanco, Madrid, Spain
| | - Mario Mellado
- Chemokine Signaling group, Department of Immunology and Oncology, Centro Nacional de Biotecnología/CSIC, Campus de Cantoblanco, Madrid, Spain
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Meng Q, Zhu R, Mao Y, Zhu S, Wu Y, Huang L, Ciechanover A, An J, Xu Y, Huang Z. Biological and mutational analyses of CXCR4-antagonist interactions and design of new antagonistic analogs. Biosci Rep 2023; 43:BSR20230981. [PMID: 38131305 PMCID: PMC10987480 DOI: 10.1042/bsr20230981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 11/05/2023] [Accepted: 11/21/2023] [Indexed: 12/23/2023] Open
Abstract
The chemokine receptor CXCR4 has become an attractive therapeutic target for HIV-1 infection, hematopoietic stem cell mobilization, and cancer metastasis. A wide variety of synthetic antagonists of CXCR4 have been developed and studied for a growing list of clinical applications. To compare the biological effects of different antagonists on CXCR4 functions and their common and/or distinctive molecular interactions with the receptor, we conducted head-to-head comparative cell-based biological and mutational analyses of the interactions with CXCR4 of eleven reported antagonists, including HC4319, DV3, DV1, DV1 dimer, V1, vMIP-II, CVX15, LY2510924, IT1t, AMD3100, and AMD11070 that were representative of different structural classes of D-peptides, L-peptide, natural chemokine, cyclic peptides, and small molecules. The results were rationalized by molecular modeling of CXCR4-antagonist interactions from which the common as well as different receptor binding sites of these antagonists were derived, revealing a number of important residues such as W94, D97, H113, D171, D262, and E288, mostly of negative charge. To further examine this finding, we designed and synthesized new antagonistic analogs by adding positively charged residues Arg to a D-peptide template to enhance the postulated charge-charge interactions. The newly designed analogs displayed significantly increased binding to CXCR4, which supports the notion that negatively charged residues of CXCR4 can engage in interactions with moieties of positive charge of the antagonistic ligands. The results from these mutational, modeling and new analog design studies shed new insight into the molecular mechanisms of different types of antagonists in recognizing CXCR4 and guide the development of new therapeutic agents.
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Affiliation(s)
- Qian Meng
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Ruohan Zhu
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yujia Mao
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Siyu Zhu
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yi Wu
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Lina S.M. Huang
- Division of Infectious Diseases and Global Public Heath, Department of Medicine, School of Medicine, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093, U.S.A
| | - Aaron Ciechanover
- The Rapport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa 3109601, Israel
- Ciechanover Institute of Precision and Regenerative Medicine, School of Medicine, Chinese University of Hong Kong, Shenzhen 518172, China
| | - Jing An
- Division of Infectious Diseases and Global Public Heath, Department of Medicine, School of Medicine, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093, U.S.A
| | - Yan Xu
- Ciechanover Institute of Precision and Regenerative Medicine, School of Medicine, Chinese University of Hong Kong, Shenzhen 518172, China
| | - Ziwei Huang
- School of Life Sciences, Tsinghua University, Beijing 100084, China
- Division of Infectious Diseases and Global Public Heath, Department of Medicine, School of Medicine, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093, U.S.A
- Ciechanover Institute of Precision and Regenerative Medicine, School of Medicine, Chinese University of Hong Kong, Shenzhen 518172, China
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Zhuo Y, Crecelius JM, Marchese A. G protein-coupled receptor kinase phosphorylation of distal C-tail sites specifies βarrestin1-mediated signaling by chemokine receptor CXCR4. J Biol Chem 2022; 298:102351. [PMID: 35940305 PMCID: PMC9465349 DOI: 10.1016/j.jbc.2022.102351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 07/29/2022] [Accepted: 08/01/2022] [Indexed: 10/25/2022] Open
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Jansen M, Beaumelle B. How palmitoylation affects trafficking and signaling of membrane receptors. Biol Cell 2021; 114:61-72. [PMID: 34738237 DOI: 10.1111/boc.202100052] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 10/06/2021] [Accepted: 10/19/2021] [Indexed: 01/10/2023]
Abstract
S-acylation (or palmitoylation) is a reversible post-translational modification (PTM) that modulates protein activity, signalization and trafficking. Palmitoylation was found to significantly impact the activity of various membrane receptors involved in either pathogen entry, such as CCR5 (for HIV) and anthrax toxin receptors, cell proliferation (epidermal growth factor receptor), cardiac function (β-Adrenergic receptor), or synaptic function (AMPA receptor). Palmitoylation of these membrane receptors indeed affects not only their internalization, localization, and activation, but also other PTMs such as phosphorylation. In this review, we discuss recent results showing how palmitoylation differently affects the biology of these membrane receptors.
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Affiliation(s)
- Maxime Jansen
- Institut de Recherche en Infectiologie de Montpellier (IRIM), UMR9004-Université de Montpellier-CNRS, Montpellier, France
| | - Bruno Beaumelle
- Institut de Recherche en Infectiologie de Montpellier (IRIM), UMR9004-Université de Montpellier-CNRS, Montpellier, France
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Hickey KN, Grassi SM, Caplan MR, Stabenfeldt SE. Stromal Cell-Derived Factor-1a Autocrine/Paracrine Signaling Contributes to Spatiotemporal Gradients in the Brain. Cell Mol Bioeng 2021; 14:75-87. [PMID: 33643467 PMCID: PMC7878637 DOI: 10.1007/s12195-020-00643-y] [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: 05/29/2020] [Accepted: 07/27/2020] [Indexed: 11/27/2022] Open
Abstract
INTRODUCTION Stromal cell derived factor-1a (SDF-1a) and its receptor CXCR4 modulate stem cell recruitment to neural injury sites. SDF-1a gradients originating from injury sites contribute to chemotactic cellular recruitment. To capitalize on this injury-induced cell recruitment, further investigation of SDF-1a/CXCR4 signaling dynamics are warranted. Here, we studied how exogenous SDF-1a delivery strategies impact spatiotemporal SDF-1a levels and the role autocrine/paracrine signaling plays. METHODS We first assessed total SDF-1a and CXCR4 levels over the course of 7 days following intracortical injection of either bolus SDF-1a or SDF-1a loaded nanoparticles in CXCR4-EGFP mice. We then investigated cellular contributors to SDF-1a autocrine/paracrine signaling via time course in vitro measurements of SDF-1a and CXCR4 gene expression following exogenous SDF-1a application. Lastly, we created mathematical models that could recapitulate our in vivo observations. RESULTS In vivo, we found sustained total SDF-1a levels beyond 3 days post injection, indicating endogenous SDF-1a production. We confirmed in vitro that microglia, astrocytes, and brain endothelial cells significantly change SDF-1a and CXCR4 expression after exposure. We found that diffusion-only based mathematical models were unable to capture in vivo SDF-1a spatial distribution. Adding autocrine/paracrine mechanisms to the model allowed for SDF-1a temporal trends to be modeled accurately, indicating it plays an essential role in SDF-1a sustainment. CONCLUSIONS We conclude that autocrine/paracrine dynamics play a role in endogenous SDF-1a levels in the brain following exogenous delivery. Implementation of these dynamics are necessary to improving SDF-1a delivery strategies. Further, mathematical models introduced here may be utilized in predicting future outcomes based upon new biomaterial designs.
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Affiliation(s)
- Kassondra N. Hickey
- School of Biological and Health Systems Engineering, Arizona State University, PO Box 879709, Tempe, AZ 85287-9709 USA
| | - Shannon M. Grassi
- School of Biological and Health Systems Engineering, Arizona State University, PO Box 879709, Tempe, AZ 85287-9709 USA
| | - Michael R. Caplan
- Phoenix Country Day School, Upper School Faculty, Paradise Valley, AZ USA
| | - Sarah E. Stabenfeldt
- School of Biological and Health Systems Engineering, Arizona State University, PO Box 879709, Tempe, AZ 85287-9709 USA
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Revisiting Cell Death Responses in Fibrotic Lung Disease: Crosstalk between Structured and Non-Structured Cells. Diagnostics (Basel) 2020; 10:diagnostics10070504. [PMID: 32708315 PMCID: PMC7400296 DOI: 10.3390/diagnostics10070504] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 07/16/2020] [Accepted: 07/20/2020] [Indexed: 02/06/2023] Open
Abstract
Fibrosis is a life-threatening disorder caused by excessive formation of connective tissue that can affect several critical organs. Innate immune cells are involved in the development of various disorders, including lung fibrosis. To date, several hematopoietic cell types have been implicated in fibrosis, including pro-fibrotic monocytes like fibrocytes and segregated-nucleus-containing atypical monocytes (SatMs), but the precise cellular and molecular mechanisms underlying its development remain unclear. Repetitive injury and subsequent cell death response are triggering events for lung fibrosis development. Crosstalk between lung structured and non-structured cells is known to regulate the key molecular event. We recently reported that RNA-binding motif protein 7 (RBM7) expression is highly upregulated in the fibrotic lung and plays fundamental roles in fibrosis development. RBM7 regulates nuclear degradation of NEAT1 non-coding RNA, resulting in sustained apoptosis in the lung epithelium and fibrosis. Apoptotic epithelial cells produce CXCL12, which leads to the recruitment of pro-fibrotic monocytes. Apoptosis is also the main source of autoantigens. Recent studies have revealed important functions for natural autoantibodies that react with specific sets of self-antigens and are unique to individual diseases. Here, we review recent insights into lung fibrosis development in association with crosstalk between structured cells like lung epithelial cells and non-structured cells like migrating immune cells, and discuss their relevance to acquired immunity through natural autoantibody production.
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Mousavi A. CXCL12/CXCR4 signal transduction in diseases and its molecular approaches in targeted-therapy. Immunol Lett 2019; 217:91-115. [PMID: 31747563 DOI: 10.1016/j.imlet.2019.11.007] [Citation(s) in RCA: 100] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 11/01/2019] [Accepted: 11/15/2019] [Indexed: 02/08/2023]
Abstract
Chemokines are small molecules called "chemotactic cytokines" and regulate many processes like leukocyte trafficking, homing of immune cells, maturation, cytoskeletal rearrangement, physiology, migration during development, and host immune responses. These proteins bind to their corresponding 7-membrane G-protein-coupled receptors. Chemokines and their receptors are anti-inflammatory factors in autoimmune conditions, so consider as potential targets for neutralization in such diseases. They also express by cancer cells and function as angiogenic factors, and/or survival/growth factors that enhance tumor angiogenesis and development. Among chemokines, the CXCL12/CXCR4 axis has significantly been studied in numerous cancers and autoimmune diseases. CXCL12 is a homeostatic chemokine, which is acts as an anti-inflammatory chemokine during autoimmune inflammatory responses. In cancer cells, CXCL12 acts as an angiogenic, proliferative agent and regulates tumor cell apoptosis as well. CXCR4 has a role in leukocyte chemotaxis in inflammatory situations in numerous autoimmune diseases, as well as the high levels of CXCR4, observed in different types of human cancers. These findings suggest CXCL12/CXCR4 as a potential therapeutic target for therapy of autoimmune diseases and open a new approach to targeted-therapy of cancers by neutralizing CXCL12 and CXCR4. In this paper, we reviewed the current understanding of the role of the CXCL12/CXCR4 axis in disease pathology and cancer biology, and discuss its therapeutic implications in cancer and diseases.
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Martínez-Muñoz L, Rodríguez-Frade JM, Barroso R, Sorzano CÓS, Torreño-Pina JA, Santiago CA, Manzo C, Lucas P, García-Cuesta EM, Gutierrez E, Barrio L, Vargas J, Cascio G, Carrasco YR, Sánchez-Madrid F, García-Parajo MF, Mellado M. Separating Actin-Dependent Chemokine Receptor Nanoclustering from Dimerization Indicates a Role for Clustering in CXCR4 Signaling and Function. Mol Cell 2019; 70:106-119.e10. [PMID: 29625032 DOI: 10.1016/j.molcel.2018.02.034] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 01/08/2018] [Accepted: 02/27/2018] [Indexed: 01/03/2023]
Abstract
A current challenge in cell motility studies is to understand the molecular and physical mechanisms that govern chemokine receptor nanoscale organization at the cell membrane, and their influence on cell response. Using single-particle tracking and super-resolution microscopy, we found that the chemokine receptor CXCR4 forms basal nanoclusters in resting T cells, whose extent, dynamics, and signaling strength are modulated by the orchestrated action of the actin cytoskeleton, the co-receptor CD4, and its ligand CXCL12. We identified three CXCR4 structural residues that are crucial for nanoclustering and generated an oligomerization-defective mutant that dimerized but did not form nanoclusters in response to CXCL12, which severely impaired signaling. Overall, our data provide new insights to the field of chemokine biology by showing that receptor dimerization in the absence of nanoclustering is unable to fully support CXCL12-mediated responses, including signaling and cell function in vivo.
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Affiliation(s)
- Laura Martínez-Muñoz
- Chemokine Signaling Group, Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, 28049 Madrid, Spain; Department of Cell Signaling, Centro Andaluz de Biología Molecular y Medicina Regenerativa (CSIC), 41092 Sevilla, Spain.
| | - José Miguel Rodríguez-Frade
- Chemokine Signaling Group, Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, 28049 Madrid, Spain
| | - Rubén Barroso
- Chemokine Signaling Group, Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, 28049 Madrid, Spain
| | - Carlos Óscar S Sorzano
- Biocomputing Unit, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, 28049 Madrid, Spain
| | - Juan A Torreño-Pina
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Barcelona, Spain
| | - César A Santiago
- X-ray Crystallography Unit, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, 28049 Madrid, Spain
| | - Carlo Manzo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Barcelona, Spain; Universitat de Vic, Universitat Central de Catalunya (UVic-UCC), 08500 Vic, Spain
| | - Pilar Lucas
- Chemokine Signaling Group, Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, 28049 Madrid, Spain
| | - Eva M García-Cuesta
- Chemokine Signaling Group, Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, 28049 Madrid, Spain
| | - Enric Gutierrez
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Barcelona, Spain
| | - Laura Barrio
- B Cell Dynamics Group, Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, 28049 Madrid, Spain
| | - Javier Vargas
- Biocomputing Unit, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, 28049 Madrid, Spain; Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
| | - Graciela Cascio
- Chemokine Signaling Group, Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, 28049 Madrid, Spain
| | - Yolanda R Carrasco
- B Cell Dynamics Group, Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, 28049 Madrid, Spain
| | | | - María F García-Parajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Barcelona, Spain; ICREA, Pg. Lluís Companys 23, 08010 Barcelona, Spain
| | - Mario Mellado
- Chemokine Signaling Group, Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, 28049 Madrid, Spain.
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Petti LM, Marlatt SA, Luo Y, Scheideman EH, Shelar A, DiMaio D. Regulation of C-C chemokine receptor 5 (CCR5) stability by Lys 197 and by transmembrane protein aptamers that target it for lysosomal degradation. J Biol Chem 2018; 293:8787-8801. [PMID: 29678881 DOI: 10.1074/jbc.ra117.001067] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 04/06/2018] [Indexed: 12/31/2022] Open
Abstract
C-C motif chemokine receptor 5 (CCR5) is a cell surface-associated, immune-regulatory G protein-coupled receptor (GCPR) with seven transmembrane helices. We previously reported the isolation and initial characterization of short artificial transmembrane protein aptamers, named "traptamers," that specifically down-regulate CCR5 expression and inhibit infection of human T cells by HIV strains that use CCR5 as a co-receptor. Here, we investigated the mechanism of traptamer-mediated CCR5 down-regulation and show that most of the traptamers (designated class 1 traptamers) form a stable complex with CCR5 and target it for lysosome-mediated degradation. The ability of these traptamers to down-regulate CCR5 depended on Lys197 in the fifth transmembrane helix of CCR5. In the absence of traptamers, substitution of Lys197 to an uncharged amino acid increased CCR5 stability, and introduction of a lysine at the homologous position in CCR2b, a related chemokine receptor, decreased CCR2b levels. The prototypic class 2 traptamer BY6M4 also formed a complex with CCR5, but CCR5 down-regulation caused by class 2 traptamers did not depend on the lysosome or on Lys197 These results demonstrate that traptamers use diverse mechanisms to down-regulate CCR5 and identify a specific amino acid that plays a central role in controlling chemokine receptor stability. Further studies of these traptamers are likely to provide new insights into CCR5 metabolism and biology and may suggest new therapeutic approaches to modulate the levels of CCR5 and other GPCRs.
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Affiliation(s)
- Lisa M Petti
- From the Department of Genetics, Yale School of Medicine, New Haven, Connecticut 06520-8005
| | - Sara A Marlatt
- From the Department of Genetics, Yale School of Medicine, New Haven, Connecticut 06520-8005
| | - Yong Luo
- From the Department of Genetics, Yale School of Medicine, New Haven, Connecticut 06520-8005
| | - Elizabeth H Scheideman
- From the Department of Genetics, Yale School of Medicine, New Haven, Connecticut 06520-8005
| | - Ashish Shelar
- From the Department of Genetics, Yale School of Medicine, New Haven, Connecticut 06520-8005
| | - Daniel DiMaio
- From the Department of Genetics, Yale School of Medicine, New Haven, Connecticut 06520-8005, .,the Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520-8024.,the Department of Therapeutic Radiology, Yale School of Medicine, New Haven, Connecticut 06520-8040, and.,the Yale Cancer Center, New Haven, Connecticut 06520-8028
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10
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Venuti A, Pastori C, Siracusano G, Pennisi R, Riva A, Tommasino M, Sciortino MT, Lopalco L. The Abrogation of Phosphorylation Plays a Relevant Role in the CCR5 Signalosome Formation with Natural Antibodies to CCR5. Viruses 2017; 10:E9. [PMID: 29283386 PMCID: PMC5795422 DOI: 10.3390/v10010009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 12/21/2017] [Accepted: 12/25/2017] [Indexed: 12/23/2022] Open
Abstract
The exposure to CCR5 (CC chemokine receptor 5) specific natural antibodies in vitro produces a Class B β-arrestin2-dependent CCR5 retention with the aid of ERK1, due to the formation of a CCR5 signalosome, which remains stable for at least 48 h. Considering that β-arrestins and MAPKs are receptive to environmental signals, their signal complexes could be one of the key junction for GPCRs internalization related signal transduction. Here, we demonstrate that, in T cells, the phosphorylation status of either CCR5 receptor or ERK1 protein is necessary to drive the internalized receptor into the early endosomes, forming the CCR5 signalosome. In particular, our data show that β-arrestin2/ERK1 complex is a relevant transducer in the CCR5 signaling pathway. Understanding the mechanism of CCR5 regulation is essential for many inflammatory disorders, tumorigenesis and viral infection such as HIV.
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Affiliation(s)
- Assunta Venuti
- Division of Immunology, Transplantation and Infectious Diseases, DIBIT-San Raffaele Scientific Institute, 20132 Milan, Italy.
- Infections and Cancer Biology Group, International Agency for Research on Cancer, 150 Cours Albert Thomas, 69372 Lyon CEDEX 08, France.
| | - Claudia Pastori
- Division of Immunology, Transplantation and Infectious Diseases, DIBIT-San Raffaele Scientific Institute, 20132 Milan, Italy.
| | - Gabriel Siracusano
- Division of Immunology, Transplantation and Infectious Diseases, DIBIT-San Raffaele Scientific Institute, 20132 Milan, Italy.
| | - Rosamaria Pennisi
- Department of Chemical Biological Pharmaceutical and Environmental Sciences, University of Messina, 98166 Messina, Italy.
| | - Agostino Riva
- Third Division of Infectious Diseases, Luigi Sacco Hospital, University of Milan, 20157 Milan, Italy.
| | - Massimo Tommasino
- Infections and Cancer Biology Group, International Agency for Research on Cancer, 150 Cours Albert Thomas, 69372 Lyon CEDEX 08, France.
| | - Maria Teresa Sciortino
- Department of Chemical Biological Pharmaceutical and Environmental Sciences, University of Messina, 98166 Messina, Italy.
| | - Lucia Lopalco
- Division of Immunology, Transplantation and Infectious Diseases, DIBIT-San Raffaele Scientific Institute, 20132 Milan, Italy.
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Wenzel ED, Bachis A, Avdoshina V, Taraballi F, Tasciotti E, Mocchetti I. Endocytic Trafficking of HIV gp120 is Mediated by Dynamin and Plays a Role in gp120 Neurotoxicity. J Neuroimmune Pharmacol 2017; 12:492-503. [PMID: 28349243 DOI: 10.1007/s11481-017-9739-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 03/13/2017] [Indexed: 12/13/2022]
Abstract
Neurons that endocytose the human immunodeficiency virus-1 (HIV) protein gp120 exhibit neurite retraction and activation of caspase-3, suggesting that the endocytic process may be crucial for gp120-mediated neuronal injury. The goal of this study is to demonstrate that internalization and accumulation of gp120 play a role in its neurotoxic effects. In mammalian cells, endocytosis is primarily a dynamin-dependent process. To establish whether gp120 is endocytosed in a dynamin-dependent manner, we used fibroblasts in which deletion of dynamins was induced by tamoxifen. We observed a robust reduction of intracellular gp120 immunoreactivity in tamoxifen-treated cells. To examine whether endocytosis of gp120 is crucial for its neurotoxic effect, we blocked gp120 internalization into primary rat cortical neurons by dynasore, an inhibitor of the dynamin GTP-ase activity. We found that dynasore blocks both gp120 internalization and neurotoxicity. We then utilized gp120-loaded mesoporous silica nanoparticles to deliver gp120 intracellularly. We established that once internalized, gp120 is neurotoxic regardless of chemokine receptor activation. Our data suggest that dynamin-dependent endocytosis of gp120 is critical for its neurotoxicity.
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Affiliation(s)
- Erin D Wenzel
- Laboratory of Preclinical Neurobiology, Department of Neuroscience, Georgetown University Medical Center, EP09 New Research Building, 3970 Reservoir Rd, NW, Washington, DC, 20057, USA.,Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, DC, 20057, USA
| | - Alessia Bachis
- Laboratory of Preclinical Neurobiology, Department of Neuroscience, Georgetown University Medical Center, EP09 New Research Building, 3970 Reservoir Rd, NW, Washington, DC, 20057, USA
| | - Valeria Avdoshina
- Laboratory of Preclinical Neurobiology, Department of Neuroscience, Georgetown University Medical Center, EP09 New Research Building, 3970 Reservoir Rd, NW, Washington, DC, 20057, USA
| | - Francesca Taraballi
- Center for Biomimetic Medicine, Houston Methodist Research Institute, Houston Methodist Hospital, Houston, TX, 77030, USA
| | - Ennio Tasciotti
- Center for Biomimetic Medicine, Houston Methodist Research Institute, Houston Methodist Hospital, Houston, TX, 77030, USA.,Department of Orthopedics, Houston Methodist Hospital, Houston, TX, 77030, USA
| | - Italo Mocchetti
- Laboratory of Preclinical Neurobiology, Department of Neuroscience, Georgetown University Medical Center, EP09 New Research Building, 3970 Reservoir Rd, NW, Washington, DC, 20057, USA.
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12
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Venuti A, Pastori C, Pennisi R, Riva A, Sciortino MT, Lopalco L. Class B β-arrestin2-dependent CCR5 signalosome retention with natural antibodies to CCR5. Sci Rep 2016; 6:39382. [PMID: 28008933 PMCID: PMC5180096 DOI: 10.1038/srep39382] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 11/16/2016] [Indexed: 12/15/2022] Open
Abstract
CCR5 stimulation with natural ligands, such as RANTES, classically induces short-term internalization with transient activation of β-arrestins and rapidly recycling on the cell surface. Here we discovered that, in T cells, natural CCR5 antibodies induce a CCR5-negative phenotype with the involvement of β-arrestin2, which leads to the formation of a stable CCR5 signalosome with both β-arrestin2 and ERK1. The activation of β-arrestin2 is necessary to CCR5 signaling for the signalosome formation and stabilization. When all stimuli were washed out, β-arrestin1 silencing favors the activity of β-arrestin2 for the CCR5 signalosome retention. Interestingly, CCR5 turn from Class A trafficking pattern, normally used for its internalization with natural modulating molecules (i.e. RANTES), into a long lasting Class B type specifically induced by stimulation with natural anti-CCR5 antibodies. This new CCR5 pathway is relevant not only to study in depth the molecular basis of all pathologies where CCR5 is involved but also to generate new antidody-based therapeutics.
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Affiliation(s)
- Assunta Venuti
- Division of Immunology, Transplantation and Infectious Diseases, San Raffaele Scientific Institute, Milan, 20132, Italy
| | - Claudia Pastori
- Division of Immunology, Transplantation and Infectious Diseases, San Raffaele Scientific Institute, Milan, 20132, Italy
| | - Rosamaria Pennisi
- Department of Chemical Biological Pharmaceutical and Environmental Sciences, University of Messina, Messina, 98166, Italy
| | - Agostino Riva
- Third Division of Infectious Diseases, Luigi Sacco Hospital, University of Milan, Milan, 20157, Italy
| | - Maria Teresa Sciortino
- Department of Chemical Biological Pharmaceutical and Environmental Sciences, University of Messina, Messina, 98166, Italy
| | - Lucia Lopalco
- Division of Immunology, Transplantation and Infectious Diseases, San Raffaele Scientific Institute, Milan, 20132, Italy
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13
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Ge XY, Fang SP, Zhou M, Luo J, Wei J, Wen XP, Yan XD, Zou Z. TLR4-dependent internalization of CX3CR1 aggravates sepsis-induced immunoparalysis. Am J Transl Res 2016; 8:5696-5705. [PMID: 28078040 PMCID: PMC5209520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 12/04/2016] [Indexed: 06/06/2023]
Abstract
Sepsis, the most severe manifestation of infection, poses a major challenge to health-care systems around the world. Limited ability to clean and remove the pathogen renders difficulty in septic patients to recover from the phase of immunoparalysis. The present study found the vital role of CX3CR1 internalization on sepsis-induced immunoparalysis. A mouse model with cecal ligation and puncture (CLP) and cell model with lipopolysaccharides (LPS) were employed to explore the relationship between CX3CR1 internalization and septic immunoparalysis. Immunoparalysis model in mice was established 4 days after CLP with significantly decreased proinflammatory cytokines. Flow cytometry analysis found a decreased surface expression of CX3CR1 during immunoparalysis, which was associated with reduced mRNA level and increased internalization of CX3CR1. G-protein coupled receptor kinase 2 (GRK2) and β-arrestin2 were significantly increased during septic immunoparalysis and involved in the internalization of CX3CR1. TLR4-/- or TLR4 inhibitor-treated macrophages exhibited an inhibited expression of GRK2 and β-arrestin2, along with reduced internalization of CX3CR1. Moreover, the knockdown of GRK2 and β-arrestin2 inhibited the internalization of CX3CR1 and led to a higher response on the second hit, which was associated with an increased activation of NF-κB. The critical association between internalization of CX3CR1 and immunosuppression in sepsis may provide a novel reference for clinical therapeutics.
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Affiliation(s)
- Xin-Yu Ge
- Department of Anesthesiology, Changzheng Hospital, The Second Military Medical UniversityShanghai, P. R. China
- Hebei North University School of MedicineZhangjiakou, Hebei, P. R. China
| | - Shang-Ping Fang
- Department of Anesthesiology, Changzheng Hospital, The Second Military Medical UniversityShanghai, P. R. China
| | - Miao Zhou
- Department of Anesthesiology and SICU, Xinhua Hospital, Shanghai Jiaotong University, School of MedicineShanghai, P. R. China
| | - Jing Luo
- Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical UniversityXuzhou, Jiangsu Province, P. R. China
- Department of Anesthesiology, Shanghai Pulmonary Hospital, Tongji University School of MedicineShanghai, P. R. China
| | - Juan Wei
- Soochow UniversitySuzhou, P. R. China
- Department of Anesthesiology, Shanghai Pulmonary Hospital, Tongji University School of MedicineShanghai, P. R. China
| | - Xue-Ping Wen
- Department of Orthopedics, Ningxiang People’s Hospital of Hunan ProvinceNingxiang, Hunan, P. R. China
| | - Xiao-Di Yan
- Department of Anesthesiology, Changzheng Hospital, The Second Military Medical UniversityShanghai, P. R. China
| | - Zui Zou
- Department of Anesthesiology, Changzheng Hospital, The Second Military Medical UniversityShanghai, P. R. China
- Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical UniversityXuzhou, Jiangsu Province, P. R. China
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14
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Glass JJ, Yuen D, Rae J, Johnston APR, Parton RG, Kent SJ, De Rose R. Human immune cell targeting of protein nanoparticles--caveospheres. NANOSCALE 2016; 8:8255-8265. [PMID: 27031090 DOI: 10.1039/c6nr00506c] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Nanotechnology has the power to transform vaccine and drug delivery through protection of payloads from both metabolism and off-target effects, while facilitating specific delivery of cargo to immune cells. However, evaluation of immune cell nanoparticle targeting is conventionally restricted to monocultured cell line models. We generated human caveolin-1 nanoparticles, termed caveospheres, which were efficiently functionalized with monoclonal antibodies. Using this platform, we investigated CD4+ T cell and CD20+ B cell targeting within physiological mixtures of primary human blood immune cells using flow cytometry, imaging flow cytometry and confocal microscopy. Antibody-functionalization enhanced caveosphere binding to targeted immune cells (6.6 to 43.9-fold) within mixed populations and in the presence of protein-containing fluids. Moreover, targeting caveospheres to CCR5 enabled caveosphere internalization by non-phagocytic CD4+ T cells--an important therapeutic target for HIV treatment. This efficient and flexible system of immune cell-targeted caveosphere nanoparticles holds promise for the development of advanced immunotherapeutics and vaccines.
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Affiliation(s)
- Joshua J Glass
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC 3010, Australia and ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, The University of Melbourne, Melbourne, Australia
| | - Daniel Yuen
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia and ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash University, Parkville, Australia
| | - James Rae
- Institute for Molecular Bioscience and Centre for Microscopy and Microanalysis, The University of Queensland, St Lucia, QLD 4072, Australia and ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, The University of Queensland, St Lucia, Australia
| | - Angus P R Johnston
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia and ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash University, Parkville, Australia
| | - Robert G Parton
- Institute for Molecular Bioscience and Centre for Microscopy and Microanalysis, The University of Queensland, St Lucia, QLD 4072, Australia and ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, The University of Queensland, St Lucia, Australia
| | - Stephen J Kent
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC 3010, Australia and ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, The University of Melbourne, Melbourne, Australia and Melbourne Sexual Health Centre and Department of Infectious Diseases, Alfred Health, Central Clinical School, Monash University, Melbourne, Australia.
| | - Robert De Rose
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC 3010, Australia and ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, The University of Melbourne, Melbourne, Australia
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15
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Liu Q, Pan C, Lopez L, Gao J, Velez D, Anaya-O'Brien S, Ulrick J, Littel P, Corns JS, Ellenburg DT, Malech HL, Murphy PM, McDermott DH. WHIM Syndrome Caused by Waldenström's Macroglobulinemia-Associated Mutation CXCR4 (L329fs). J Clin Immunol 2016; 36:397-405. [PMID: 27059040 DOI: 10.1007/s10875-016-0276-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 03/21/2016] [Indexed: 11/28/2022]
Abstract
WHIM syndrome is an autosomal dominant immunodeficiency disease caused by mutations affecting the carboxy-terminus of CXCR4. To characterize novel genetic causes of the syndrome, we recruited a pediatric patient with possible WHIM syndrome, performed CXCR4 gene sequencing and compared his clinical phenotype and CXCR4 tail amino acid sequences with other patients with WHIM syndrome carrying CXCR4 (R334X) mutations. We identified and biochemically characterized a heterozygous 5 base pair deletion (nucleotides 986-990) located in the portion of the open reading frame (ORF) of CXCR4 that encodes the carboxy-terminal domain of the receptor. This CXCR4 (L329fs) mutation causes a frame-shift at codon 329 resulting in replacement of the final 24 predicted amino acids of the receptor with 12 missense amino acids. Like previously reported WHIM mutations, this frame-shift mutation CXCR4 (L329fs) decreased receptor downregulation in response to the CXCR4 agonist CXCL12 in patient PBMCs as well as in transfected K562 and HEK 293 cells, but increased calcium flux responses in K562 cells to CXCL12 stimulation. Thus, CXCR4 (L329fs) appears to be a de novo autosomal dominant frame-shift gain-of-function mutation that like other carboxy-terminus mutations causes WHIM syndrome. The same CXCR4 (L329fs) frame-shift variant has been reported to occur in tumor cells from a patient with Waldenström's Macroglobulemia (WM), but is caused by a distinct genetic mechanism: insertion of a single nucleotide in the L329 codon, providing additional evidence that the carboxy-terminus of CXCR4 is a genetic hotspot for mutation.
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Affiliation(s)
- Qian Liu
- Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bldg. 10, Room 11 N107, Bethesda, MD, 20892-1886, USA
| | - Catherina Pan
- Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bldg. 10, Room 11 N107, Bethesda, MD, 20892-1886, USA
| | - Lizbeeth Lopez
- Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bldg. 10, Room 11 N107, Bethesda, MD, 20892-1886, USA
| | - Jiliang Gao
- Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bldg. 10, Room 11 N107, Bethesda, MD, 20892-1886, USA
| | - Daniel Velez
- Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bldg. 10, Room 11 N107, Bethesda, MD, 20892-1886, USA
| | - Sandra Anaya-O'Brien
- Laboratory of Host Defenses, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Jean Ulrick
- Laboratory of Host Defenses, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Patricia Littel
- Laboratory of Host Defenses, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - John S Corns
- Pediatric Hematology/Oncology, East Tennessee Children's Hospital, Knoxville, TN, USA
| | | | - Harry L Malech
- Laboratory of Host Defenses, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Philip M Murphy
- Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bldg. 10, Room 11 N107, Bethesda, MD, 20892-1886, USA
| | - David H McDermott
- Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bldg. 10, Room 11 N107, Bethesda, MD, 20892-1886, USA.
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16
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Beletkaia E, Fenz SF, Pomp W, Snaar-Jagalska BE, Hogendoorn PW, Schmidt T. CXCR4 signaling is controlled by immobilization at the plasma membrane. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:607-16. [DOI: 10.1016/j.bbamcr.2015.12.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 12/23/2015] [Accepted: 12/29/2015] [Indexed: 12/14/2022]
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17
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Venuti A, Pastori C, Siracusano G, Riva A, Sciortino MT, Lopalco L. ERK1-Based Pathway as a New Selective Mechanism To Modulate CCR5 with Natural Antibodies. THE JOURNAL OF IMMUNOLOGY 2015; 195:3045-57. [PMID: 26324779 DOI: 10.4049/jimmunol.1500708] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 07/28/2015] [Indexed: 01/21/2023]
Abstract
Natural human Abs, recognizing an epitope within the first extramembrane loop of CCR5 (the main HIV coreceptor), induce a long-lasting internalization (48 h) of the protein, whereas all known CCR5 modulating molecules show a short-term kinetics (60-90 min). Despite extensive studies on the regulation of CCR5 signaling cascades, which are the effect of concomitant CCR5 internalization by exogenous stimuli such as Abs, downstream signaling continues to be poorly understood. In this article, we report a hitherto unrecognized mechanism of CCR5 modulation mediated by G protein-dependent ERK1 activity. We further demonstrate that ERK1 is localized mainly in the cytoplasmic compartment and that it interacts directly with the CCR5 protein, thus provoking possible CCR5 degradation with a subsequent de novo synthesis, and that re-expression of CCR5 on the cell membrane required several days. In contrast, the RANTES treatment induces a recovery of the receptor on the cell membrane in short-term kinetics without the involvement of de novo protein synthesis. The said new pathway could be relevant not only to better understand the molecular basis of all pathologic conditions in which CCR5 is involved but also to generate new tools to block viral infections, such as the use of recombinant Abs.
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Affiliation(s)
- Assunta Venuti
- Division of Immunology, Transplantation and Infectious Diseases, San Raffaele Scientific Institute, 20127 Milan, Italy
| | - Claudia Pastori
- Division of Immunology, Transplantation and Infectious Diseases, San Raffaele Scientific Institute, 20127 Milan, Italy
| | - Gabriel Siracusano
- Department of Biological and Environmental Sciences, University of Messina, 98166 Messina, Italy; and
| | - Agostino Riva
- Third Division of Infectious Diseases, Luigi Sacco Hospital, University of Milan, 20157 Milan, Italy
| | - Maria Teresa Sciortino
- Department of Biological and Environmental Sciences, University of Messina, 98166 Messina, Italy; and
| | - Lucia Lopalco
- Division of Immunology, Transplantation and Infectious Diseases, San Raffaele Scientific Institute, 20127 Milan, Italy;
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18
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McDermott DH, Gao JL, Murphy PM. Chromothriptic cure of WHIM syndrome: Implications for bone marrow transplantation. Rare Dis 2015; 3:e1073430. [PMID: 26459672 PMCID: PMC4588533 DOI: 10.1080/21675511.2015.1073430] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 07/11/2015] [Indexed: 11/21/2022] Open
Abstract
We recently reported a 59 year old female, designated WHIM-09, who was born with the rare immunodeficiency disease WHIM syndrome but underwent spontaneous phenotypic reversion as an adult. The causative WHIM mutation CXCR4R334X was absent in her myeloid and erythroid lineage, but present in her lymphoid lineage and in epithelial cells, defining her as a somatic genetic mosaic. Genomic and hematologic analysis revealed chromothripsis (chromosome shattering) on one copy of chromosome 2, which deleted 164 genes including CXCR4R334X in a single haematopoietic stem cell (HSC) (Fig. 1). Experiments in mice indicated that deleting one copy of Cxcr4 is sufficient to confer a selective advantage for engraftment of transplanted HSCs, suggesting a mechanism for clinical cure in WHIM-09. Genome editing may allow autologous transplantation of HSCs lacking one copy of CXCR4 without bone marrow conditioning as a general cure strategy in WHIM syndrome, safely recapitulating the outcome in patient WHIM-09.
Chromothripsis (chromosomal shattering) resulted in clinical cure of a patient with a rare immunodeficiency (WHIM syndrome) by deleting the mutant copy of CXCR4. ![]()
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Affiliation(s)
- David H McDermott
- Laboratory of Molecular Immunology; National Institute of Allergy and Infectious Diseases; National Institutes of Health ; Bethesda, MD USA
| | - Ji-Liang Gao
- Laboratory of Molecular Immunology; National Institute of Allergy and Infectious Diseases; National Institutes of Health ; Bethesda, MD USA
| | - Philip M Murphy
- Laboratory of Molecular Immunology; National Institute of Allergy and Infectious Diseases; National Institutes of Health ; Bethesda, MD USA
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19
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McDermott DH, Gao JL, Liu Q, Siwicki M, Martens C, Jacobs P, Velez D, Yim E, Bryke CR, Hsu N, Dai Z, Marquesen MM, Stregevsky E, Kwatemaa N, Theobald N, Long Priel DA, Pittaluga S, Raffeld MA, Calvo KR, Maric I, Desmond R, Holmes KL, Kuhns DB, Balabanian K, Bachelerie F, Porcella SF, Malech HL, Murphy PM. Chromothriptic cure of WHIM syndrome. Cell 2015; 160:686-699. [PMID: 25662009 PMCID: PMC4329071 DOI: 10.1016/j.cell.2015.01.014] [Citation(s) in RCA: 147] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 11/03/2014] [Accepted: 01/05/2015] [Indexed: 12/18/2022]
Abstract
Chromothripsis is a catastrophic cellular event recently described in cancer in which chromosomes undergo massive deletion and rearrangement. Here, we report a case in which chromothripsis spontaneously cured a patient with WHIM syndrome, an autosomal dominant combined immunodeficiency disease caused by gain-of-function mutation of the chemokine receptor CXCR4. In this patient, deletion of the disease allele, CXCR4(R334X), as well as 163 other genes from one copy of chromosome 2 occurred in a hematopoietic stem cell (HSC) that repopulated the myeloid but not the lymphoid lineage. In competitive mouse bone marrow (BM) transplantation experiments, Cxcr4 haploinsufficiency was sufficient to confer a strong long-term engraftment advantage of donor BM over BM from either wild-type or WHIM syndrome model mice, suggesting a potential mechanism for the patient's cure. Our findings suggest that partial inactivation of CXCR4 may have general utility as a strategy to promote HSC engraftment in transplantation.
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Affiliation(s)
- David H McDermott
- Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ji-Liang Gao
- Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Qian Liu
- Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Marie Siwicki
- Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Craig Martens
- Research Technologies Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA
| | - Paejonette Jacobs
- Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Daniel Velez
- Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Erin Yim
- Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Christine R Bryke
- Quest Diagnostics, Chantilly, VA 20151, USA; Department of Cytogenetics, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
| | - Nancy Hsu
- Quest Diagnostics, Chantilly, VA 20151, USA; Department of Cytogenetics, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
| | - Zunyan Dai
- Quest Diagnostics, Chantilly, VA 20151, USA; Department of Human Genetics, Emory University School of Medicine, Decatur, GA 30030, USA
| | - Martha M Marquesen
- Laboratory of Host Defenses, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Elina Stregevsky
- Research Technologies Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Nana Kwatemaa
- Laboratory of Host Defenses, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Narda Theobald
- Laboratory of Host Defenses, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Debra A Long Priel
- Clinical Services Program, Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, Frederick, MD 21701, USA
| | - Stefania Pittaluga
- Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Mark A Raffeld
- Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Katherine R Calvo
- Division of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA
| | - Irina Maric
- Division of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ronan Desmond
- Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA; Department of Haematology, Tallaght Hospital, Dublin 24, Ireland
| | - Kevin L Holmes
- Research Technologies Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Douglas B Kuhns
- Clinical Services Program, Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, Frederick, MD 21701, USA
| | - Karl Balabanian
- INSERM UMR- S996, Laboratory of Excellence in Research on Medication and Innovative Therapeutics, Université Paris-Sud, 92140 Clamart, France
| | - Françoise Bachelerie
- INSERM UMR- S996, Laboratory of Excellence in Research on Medication and Innovative Therapeutics, Université Paris-Sud, 92140 Clamart, France
| | - Stephen F Porcella
- Research Technologies Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA
| | - Harry L Malech
- Laboratory of Host Defenses, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Philip M Murphy
- Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
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20
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Niu H, Yang X, Xu Z, Du T, Wang R. Cell surface nucleolin interacts with CXCR4 receptor via the 212 c-terminal portion. Tumour Biol 2015; 36:1099-104. [PMID: 25326811 DOI: 10.1007/s13277-014-2734-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2014] [Accepted: 10/12/2014] [Indexed: 01/24/2023] Open
Abstract
Previously, we reported that CXCR4 receptor interacted with cell surface nucleolin, and the synergy of CXCR4 and nucleolin plays an essential role in malignant transformation. Here, we continued to conduct a structure-function analysis of nucleolin to identify which portion can efficaciously bind to CXCR4. In the present study, the expression of CXCR4 and nucleolin in 100 cases of papillary thyroid cancer (PTC) samples was investigated through immunohistochemistry (IHC). Subsequently, using nucleolin mutants and pull-down assay, we investigated precise interactions between CXCR4 and nucleolin in HEK-293 cells. A previous study demonstrated CXCR4 and nucleolin co-expressed in cell lines, and the present study further identified that CXCR4 and nucleolin co-expressed in PTC tissues, instead of normal tissues. The nucleolin mutant analysis revealed that nucleolin can efficaciously bind CXCR4 to activate CXCR4 signaling by 212 C-terminal domain. Conversely, N-terminal, RBD and GAR mutants of nucleolin showed no sign of activation of CXCR4 signaling, and differences were statistically insignificant (p > 0.05). In conclusion, these results suggested nucleolin is essential to activate CXCR4 signaling via 212 C-terminal domain, which is required for cell growth, migration, and invasiveness. Furthermore, nucleolin may interact with more G protein-coupled receptors, at least chemokine receptor. Our study will lay a new foundation for cancer therapy by antagonizing nucleolin and CXCR4.
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Affiliation(s)
- Hongxin Niu
- Department of General Surgery, Affiliated Hospital of Shandong Academy of Medical Sciences, 38# Wuyingshan Road, Jinan, 250031, China,
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Herpes simplex virus enhances chemokine function through modulation of receptor trafficking and oligomerization. Nat Commun 2015; 6:6163. [PMID: 25625471 DOI: 10.1038/ncomms7163] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2014] [Accepted: 12/19/2014] [Indexed: 01/13/2023] Open
Abstract
Glycoprotein G (gG) from herpes simplex virus 1 and 2 (HSV-1 and HSV-2, important human neurotropic pathogens) is the first viral chemokine-binding protein found to potentiate chemokine function. Here we show that gG attaches to cell surface glycosaminoglycans and induces lipid raft clustering, increasing the incorporation of CXCR4 receptors into these microdomains. gG induces conformational rearrangements in CXCR4 homodimers and changes their intracellular partners, leading to sustained, functional chemokine/receptor complexes at the surface. This results in increased chemotaxis dependent on the cholesterol content of the plasma membrane and receptor association to Src-kinases and phosphatidylinositol-3-kinase signalling pathways, but independent of clathrin-mediated endocytosis. Furthermore, using electron microscopy, we show that such enhanced functionality is associated with the accumulation of low-order CXCR4 nanoclusters. Our results provide insights into basic mechanisms of chemokine receptor function and into a viral strategy of immune modulation.
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22
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Flegler AJ, Cianci GC, Hope TJ. CCR5 conformations are dynamic and modulated by localization, trafficking and G protein association. PLoS One 2014; 9:e89056. [PMID: 24586501 PMCID: PMC3938464 DOI: 10.1371/journal.pone.0089056] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 01/15/2014] [Indexed: 11/19/2022] Open
Abstract
CCR5 acts as the principal coreceptor during HIV-1 transmission and early stages of infection. Efficient HIV-1 entry requires a series of processes, many dependent on the conformational state of both viral envelope protein and cellular receptor. Monoclonal antibodies (MAbs) are able to identify different CCR5 conformations, allowing for their use as probes to distinguish CCR5 populations. Not all CCR5 MAbs are able to reduce HIV-1 infection, suggesting the use of select CCR5 populations for entry. In the U87.CD4.CCR5-GFP cell line, we used such HIV-1-restricting MAbs to probe the relation between localization, trafficking and G protein association for individual CCR5 conformations. We find that CCR5 conformations not only exhibit different localization and abundance patterns throughout the cell, but that they also display distinct sensitivities to endocytosis inhibition. Using chemokine analogs that vary in their HIV-1 inhibitory mechanisms, we also illustrate that responses to ligand engagement are conformation-specific. Additionally, we provide supporting evidence for the select sensitivity of conformations to G protein association. Characterizing the link between the function and dynamics of CCR5 populations has implications for understanding their selective targeting by HIV-1 and for the development of inhibitors that will block CCR5 utilization by the virus.
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Affiliation(s)
- Ayanna J. Flegler
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Gianguido C. Cianci
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Thomas J. Hope
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
- * E-mail:
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Chandrasekaran P, Moore V, Buckley M, Spurrier J, Kehrl JH, Venkatesan S. HIV-1 Nef down-modulates C-C and C-X-C chemokine receptors via ubiquitin and ubiquitin-independent mechanism. PLoS One 2014; 9:e86998. [PMID: 24489825 PMCID: PMC3906104 DOI: 10.1371/journal.pone.0086998] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 12/16/2013] [Indexed: 12/29/2022] Open
Abstract
Human and Simian Immunodeficiency virus (HIV-1, HIV-2, and SIV) encode an accessory protein, Nef, which is a pathogenesis and virulence factor. Nef is a multivalent adapter that dysregulates the trafficking of many immune cell receptors, including chemokine receptors (CKRs). Physiological endocytic itinerary of agonist occupied CXCR4 involves ubiquitinylation of the phosphorylated receptor at three critical lysine residues and dynamin-dependent trafficking through the ESCRT pathway into lysosomes for degradation. Likewise, Nef induced CXCR4 degradation was critically dependent on the three lysines in the C-terminal -SSLKILSKGK- motif. Nef directly recruits the HECT domain E3 ligases AIP4 or NEDD4 to CXCR4 in the resting state. This mechanism was confirmed by ternary interactions of Nef, CXCR4 and AIP4 or NEDD4; by reversal of Nef effect by expression of catalytically inactive AIP4-C830A mutant; and siRNA knockdown of AIP4, NEDD4 or some ESCRT-0 adapters. However, ubiquitinylation dependent lysosomal degradation was not the only mechanism by which Nef downregulated CKRs. Agonist and Nef mediated CXCR2 (and CXCR1) degradation was ubiquitinylation independent. Nef also profoundly downregulated the naturally truncated CXCR4 associated with WHIM syndrome and engineered variants of CXCR4 that resist CXCL12 induced internalization via an ubiquitinylation independent mechanism.
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Affiliation(s)
- Prabha Chandrasekaran
- Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Victoria Moore
- Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Monica Buckley
- Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Joshua Spurrier
- Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - John H. Kehrl
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Sundararajan Venkatesan
- Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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24
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Flanagan CA. Receptor Conformation and Constitutive Activity in CCR5 Chemokine Receptor Function and HIV Infection. ADVANCES IN PHARMACOLOGY 2014; 70:215-63. [DOI: 10.1016/b978-0-12-417197-8.00008-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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25
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Yang X, Xu Z, Li D, Cheng S, Fan K, Li C, Li A, Zhang J, Feng M. Cell surface nucleolin is crucial in the activation of the CXCL12/CXCR4 signaling pathway. Tumour Biol 2014; 35:333-8. [PMID: 23918302 DOI: 10.1007/s13277-013-1044-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Accepted: 07/19/2013] [Indexed: 01/19/2023] Open
Abstract
Recently, CXCL12-CXCR4 has been focused on therapeutic strategies for papillary thyroid carcinoma (PTC) and other cancers. At the same time, cell surface nucleolin is also over-expressed in PTC and others. Interestingly, a few reports suggest that either CXCR4 or cell surface nucleolin is a co-receptor for HIV-1 entry into CD4+ T cells, which indicates that there is a relationship between CXCR4 and nucleolin. In this study, antibody and siRNA were used to identify effects of cell surface nucleolin and CXCR4 on cell signaling; soft-agar colony formation assay and Transwell assay were used to determine roles of nucleolin and CXCR4 in cell proliferation and migration. Importantly, co-immunoprecipitation was used to demonstrate the relationship between CXCR4 and nucleolin. Results showed CXCR4 and nucleolin were co-expressed in PTC cell line K1, B-CPAP, and TPC-1. Either cell surface nucleolin or CXCR4 was necessary to prompt extracellular signal-regulated kinase phosphorylation. When blocked, CXCR4 or nucleolin can significantly affect TPC-1 proliferation and migration (p < 0.01). Co-immunoprecipitation analysis identified that nucleolin can bind and interact with CXCR4 to activate CXCR4 signaling. This study suggests that nucleolin is crucial in the activation of CXCR4 signaling, which affects cell growth, migration, and invasiveness. Further, nucleolin may interact with other receptors. Our study also offers new ideas for cancer therapy.
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Affiliation(s)
- Xiangshan Yang
- Department of Pathology, Affiliated Hospital of Shandong Academy of Medical Sciences, Jinan, Shandong, China,
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26
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Huijbregts RPH, Helton ES, Michel KG, Sabbaj S, Richter HE, Goepfert PA, Hel Z. Hormonal contraception and HIV-1 infection: medroxyprogesterone acetate suppresses innate and adaptive immune mechanisms. Endocrinology 2013; 154:1282-95. [PMID: 23354099 PMCID: PMC3578997 DOI: 10.1210/en.2012-1850] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Accepted: 12/18/2012] [Indexed: 12/21/2022]
Abstract
Recent observational studies indicate an association between the use of hormonal contraceptives and acquisition and transmission of HIV-1. The biological and immunological mechanisms underlying the observed association are unknown. Depot medroxyprogesterone acetate (DMPA) is a progestin-only injectable contraceptive that is commonly used in regions with high HIV-1 prevalence. Here we show that medroxyprogesterone acetate (MPA) suppresses the production of key regulators of cellular and humoral immunity involved in orchestrating the immune response to invading pathogens. MPA inhibited the production of interferon (IFN)-γ, IL-2, IL-4, IL-6, IL-12, TNFα, macrophage inflammatory protein-1α (MIP-1α), and other cytokines and chemokines by peripheral blood cells and activated T cells and reduced the production of IFNα and TNFα by plasmacytoid dendritic cells in response to Toll-like receptor-7, -8, and -9 ligands. Women using DMPA displayed lower levels of IFNα in plasma and genital secretions compared with controls with no hormonal contraception. In addition, MPA prevented the down-regulation of HIV-1 coreceptors CXCR4 and CCR5 on the surface of T cells after activation and increased HIV-1 replication in activated peripheral blood mononuclear cell cultures. The presented results suggest that MPA suppresses both innate and adaptive arms of the immune system resulting in a reduction of host resistance to invading pathogens.
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Affiliation(s)
- Richard P H Huijbregts
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294-2182, USA
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27
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Wu Y, Tapia PH, Fisher GW, Waggoner AS, Jarvik J, Sklar LA. High-throughput flow cytometry compatible biosensor based on fluorogen activating protein technology. Cytometry A 2013; 83:220-6. [PMID: 23303704 DOI: 10.1002/cyto.a.22242] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 09/30/2012] [Accepted: 11/20/2012] [Indexed: 12/16/2022]
Abstract
Monitoring the trafficking of multiple proteins simultaneously in live cells is of great interest because many receptor proteins are found to function together with others in the same cell. However, existing fluorescent labeling techniques have restricted the mechanistic study of functional receptor pairs. We have expanded a hybrid system combining fluorogen-activating protein (FAP) technology and high-throughput flow cytometry to a new type of biosensor that is robust, sensitive, and versatile. This provides the opportunity to study multiple trafficking proteins in the same cell. Human beta2 adrenergic receptor (β2AR) fused with FAP AM2.2 and murine C-C chemokines receptor type 5 fused with FAP MG13 was chosen for our model system. The function of the receptor and the binding between MG13 and fluorogen MG-2p have been characterized by flow cytometry and confocal microscopy assays. The binding of fluorogen and the FAP pair is highly specific, while both FAP-tagged fusion proteins function similarly to their wild-type counterparts. The system has successfully served as a counter screen assay to eliminate false positive compounds identified in a screen against NIH Molecular Libraries Small Molecule Repository targeting regulators of the human β2AR.
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Affiliation(s)
- Yang Wu
- UNM Center for Molecular Discovery, University of New Mexico School of Medicine, Albuquerque, New Mexico 87131, USA.
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28
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CXCR4 Stimulates Macropinocytosis: Implications for Cellular Uptake of Arginine-Rich Cell-Penetrating Peptides and HIV. ACTA ACUST UNITED AC 2012. [DOI: 10.1016/j.chembiol.2012.09.011] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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29
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Liang J, Huang W, Yu X, Ashraf A, Wary KK, Xu M, Millard RW, Ashraf M, Wang Y. Suicide gene reveals the myocardial neovascularization role of mesenchymal stem cells overexpressing CXCR4 (MSC(CXCR4)). PLoS One 2012; 7:e46158. [PMID: 23029422 PMCID: PMC3460871 DOI: 10.1371/journal.pone.0046158] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2012] [Accepted: 08/28/2012] [Indexed: 01/06/2023] Open
Abstract
Background Our previous studies indicated that MSCCXCR4 improved cardiac function after myocardial infarction (MI). This study was aimed to investigate the specific role of MSCCXCR4 in neovascularization of infarcted myocardium using a suicide gene approach. Methods MSCs were transduced with either lentivirus-null vector/GFP (MSCNull as control) or vector encoding for overexpressing CXCR4/GFP. The MSC derived-endothelial cell (EC) differentiation was assessed by a tube formation assay, Dil-ac-LDL uptake, EC marker expression, and VE-cadherin promoter activity assay. Gene expression was analyzed by quantitative RT-PCR or Western blot. The suicide gene approach was under the control of VE-cadherin promoter. In vivo studies: Cell patches containing MSCNull or MSCCXCR4 were transduced with suicide gene and implanted into the myocardium of MI rat. Rats received either ganciclovir (GCV) or vehicle after cell implantation. After one month, the cardiac functional changes and neovascularization were assessed by echocardiography, histological analysis, and micro-CT imaging. Results The expression of VEGF-A and HIF-1α was significantly higher in MSCCXCR4 as compared to MSCNull under hypoxia. Additionally, MSCCXCR4 enhanced new vessel formation and EC differentiation, as well as STAT3 phosphorylation under hypoxia. STAT3 participated in the transcription of VE-cadherin in MSCCXCR4 under hypoxia, which was inhibited by WP1066 (a STAT3 inhibitor). In addition, GCV specifically induced death of ECs with suicide gene activation. In vivo studies: MSCCXCR4 implantation promoted cardiac functional restoration, reduced infarct size, improved cardiac remodeling, and enhanced neovascularization in ischemic heart tissue. New vessels derived from MSCCXCR4 were observed at the injured heart margins and communicated with native coronary arteries. However, the derived vessel networks were reduced by GCV, reversing improvement of cardiac function. Conclusion The transplanted MSCCXCR4 enhanced neovascularization after MI by boosting release of angiogenic factors and increasing the potential of endothelial differentiation.
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MESH Headings
- Animals
- Antigens, CD/genetics
- Antigens, CD/metabolism
- Cadherins/genetics
- Cadherins/metabolism
- Cell Differentiation
- Endothelial Cells/cytology
- Endothelial Cells/metabolism
- Gene Expression
- Genes, Transgenic, Suicide
- Genetic Vectors
- Hypoxia/genetics
- Hypoxia/metabolism
- Hypoxia-Inducible Factor 1, alpha Subunit/genetics
- Hypoxia-Inducible Factor 1, alpha Subunit/metabolism
- Lentivirus/genetics
- Mesenchymal Stem Cell Transplantation
- Mesenchymal Stem Cells/cytology
- Mesenchymal Stem Cells/metabolism
- Myocardial Infarction/genetics
- Myocardial Infarction/metabolism
- Myocardium/metabolism
- Neovascularization, Physiologic
- Phosphorylation
- Rats
- Rats, Sprague-Dawley
- Receptors, CXCR4/genetics
- Receptors, CXCR4/metabolism
- STAT3 Transcription Factor/genetics
- STAT3 Transcription Factor/metabolism
- Transduction, Genetic
- Vascular Endothelial Growth Factor A/genetics
- Vascular Endothelial Growth Factor A/metabolism
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Affiliation(s)
- Jialiang Liang
- Department of Pathology, College of Medicine, University of Cincinnati Medical Center, Cincinnati, Ohio, United States of America
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30
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Toxicity mechanisms of amphotericin B and its neutralization by conjugation with arabinogalactan. Antimicrob Agents Chemother 2012; 56:5603-11. [PMID: 22908154 DOI: 10.1128/aac.00612-12] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Amphotericin B (AMB) is an effective antifungal agent. However, its therapeutic use is hampered by its toxicity, mainly due to channel formation across kidney cell membranes and the disruption of postendocytic trafficking. We previously described a safe injectable AMB-arabinogalactan (AG) conjugate with neutralized toxicity. Here we studied the mechanism of the toxicity of free AMB and its neutralization by conjugation with AG. AMB treatment of a kidney cell line modulated the trafficking of three receptors (C-X-C chemokine receptor type 4 [CXCR4], M1 receptor, and human transferrin receptor [hTfnR]) due to an increase in endosomal pH. Similar data were also obtained in yeast but with an increase in vacuolar pH and the perturbation of Hxt2-green fluorescent protein (GFP) trafficking. The conjugation of AMB with AG neutralized all elements of the toxic activity of AMB in mammalian but not in fungal cells. Based on these results, we provide an explanation of how the conjugation of AMB with AG neutralizes its toxicity in mammalian cells and add to the knowledge of the mechanism of action of free AMB in both fungal and mammalian cells.
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31
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Volpe S, Cameroni E, Moepps B, Thelen S, Apuzzo T, Thelen M. CCR2 acts as scavenger for CCL2 during monocyte chemotaxis. PLoS One 2012; 7:e37208. [PMID: 22615942 PMCID: PMC3355119 DOI: 10.1371/journal.pone.0037208] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Accepted: 04/18/2012] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Leukocyte migration is essential for effective host defense against invading pathogens and during immune homeostasis. A hallmark of the regulation of this process is the presentation of chemokines in gradients stimulating leukocyte chemotaxis via cognate chemokine receptors. For efficient migration, receptor responsiveness must be maintained whilst the cells crawl on cell surfaces or on matrices along the attracting gradient towards increasing concentrations of agonist. On the other hand agonist-induced desensitization and internalization is a general paradigm for chemokine receptors which is inconsistent with the prolonged migratory capacity. METHODOLOGY/PRINCIPAL FINDINGS Chemotaxis of monocytes was monitored in response to fluorescent CCL2-mCherry by time-lapse video microscopy. Uptake of the fluorescent agonist was used as indirect measure to follow the endogenous receptor CCR2 expressed on primary human monocytes. During chemotaxis CCL2-mCherry becomes endocytosed as cargo of CCR2, however, the internalization of CCR2 is not accompanied by reduced responsiveness of the cells due to desensitization. CONCLUSIONS/SIGNIFICANCE During chemotaxis CCR2 expressed on monocytes internalizes with the bound chemoattractant, but cycles rapidly back to the plasma membrane to maintain high responsiveness. Moreover, following relocation of the source of attractant, monocytes can rapidly reverse their polarization axis organizing a new leading edge along the newly formed gradient, suggesting a uniform distribution of highly receptive CCR2 on the plasma membrane. The present observations further indicate that during chemotaxis CCR2 acts as scavenger consuming the chemokine forming the attracting cue.
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Affiliation(s)
- Silvia Volpe
- Institute for Research in Biomedicine, Bellinzona, Switzerland
| | | | - Barbara Moepps
- Institute of Pharmacology and Toxicology, University of Ulm Medical Center, Ulm, Germany
| | - Sylvia Thelen
- Institute for Research in Biomedicine, Bellinzona, Switzerland
| | - Tiziana Apuzzo
- Institute for Research in Biomedicine, Bellinzona, Switzerland
| | - Marcus Thelen
- Institute for Research in Biomedicine, Bellinzona, Switzerland
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Röschmann KIL, van Kuijen AM, Luiten S, Jonker MJ, Breit TM, Fokkens WJ, Petersen A, van Drunen CM. Purified Timothy grass pollen major allergen Phl p 1 may contribute to the modulation of allergic responses through a pleiotropic induction of cytokines and chemokines from airway epithelial cells. Clin Exp Immunol 2012; 167:413-21. [PMID: 22288584 DOI: 10.1111/j.1365-2249.2011.04522.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
By definition, allergens are proteins with the ability to elicit powerful T helper lymphocyte type 2 (Th2) responses, culminating in immunoglobulin (Ig)E antibody production. Why specific proteins cause aberrant immune responses has remained largely unanswered. Recent data suggest that there may be several molecular paths that may affect allergenicity of proteins. The focus of this study is the response of airway epithelium to a major allergen from Phleum pratense Phl p 1. Instead of focusing on a few genes and proteins that might be affected by the major allergen, our aim was to obtain a broader view on the immune stimulatory capacity of Phl p 1. We therefore performed detailed analysis on mRNA and protein level by using a microarray approach to define Phl p 1-induced gene expression. We found that this allergen induces modulation and release of a broad range of mediators, indicating it to be a powerful trigger of the immune system. We were able to show that genes belonging to the GO cluster 'cell communication' were among the most prominent functional groups, which is also reflected in cytokines and chemokines building centres in a computational model of direct gene interaction. Further detailed comparison of grass pollen extract (GPE)- and Phl p 1-induced gene expression might be beneficial with regard to the application of single components within diagnosis and immunotherapy.
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Affiliation(s)
- K I L Röschmann
- Department of Otorhinolaryngology, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands.
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TLR signaling paralyzes monocyte chemotaxis through synergized effects of p38 MAPK and global Rap-1 activation. PLoS One 2012; 7:e30404. [PMID: 22347375 PMCID: PMC3276499 DOI: 10.1371/journal.pone.0030404] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Accepted: 12/20/2011] [Indexed: 01/15/2023] Open
Abstract
Toll-like receptors (TLRs) that recognize pathogen associated molecular patterns and chemoattractant receptors (CKRs) that orchestrate leukocyte migration to infected tissue are two arms of host innate immunity. Although TLR signaling induces synthesis and secretion of proinflammatory cytokines and chemokines, which recruit leukocytes, many studies have reported the paradoxical observation that TLR stimulation inhibits leukocyte chemotaxis in vitro and impairs their recruitment to tissues during sepsis. There is consensus that physical loss of chemokine receptor (CKR) at the RNA or protein level or receptor usage switching are the mechanisms underlying this effect. We show here that a brief (<15 min) stimulation with LPS (lipopolysaccharide) at ~0.2 ng/ml inhibited chemotactic response from CCR2, CXCR4 and FPR receptors in monocytes without downmodulation of receptors. A 3 min LPS pre-treatment abolished the polarized accumulation of F-actin, integrins and PIP(3) (phosphatidylinositol-3,4,5-trisphosphate) in response to chemokines in monocytes, but not in polymorphonuclear neutrophils (PMNs). If chemoattractants were added before or simultaneously with LPS, chemotactic polarization was preserved. LPS did not alter the initial G-protein signaling, or endocytosis kinetics of agonist-occupied chemoattractant receptors (CKRs). The chemotaxis arrest did not result from downmodulation of receptors or from inordinate increase in adhesion. LPS induced rapid p38 MAPK activation, global redistribution of activated Rap1 (Ras-proximate-1 or Ras-related protein 1) GTPase and Rap1GEF (guanylate exchange factor) Epac1 (exchange proteins activated by cyclic AMP) and disruption of intracellular gradient. Co-inhibition of p38 MAPK and Rap1 GTPase reversed the LPS induced breakdown of chemotaxis suggesting that LPS effect requires the combined function of p38 MAPK and Rap1 GTPase.
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34
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McDermott DH, Lopez J, Deng F, Liu Q, Ojode T, Chen H, Ulrick J, Kwatemaa N, Kelly C, Anaya-O'Brien S, Garofalo M, Marquesen M, Hilligoss D, DeCastro R, Malech HL, Murphy PM. AMD3100 is a potent antagonist at CXCR4(R334X) , a hyperfunctional mutant chemokine receptor and cause of WHIM syndrome. J Cell Mol Med 2012; 15:2071-81. [PMID: 21070597 PMCID: PMC3071896 DOI: 10.1111/j.1582-4934.2010.01210.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
WHIM is an acronym for a rare immunodeficiency syndrome (OMIM #193670) caused by autosomal dominant mutations truncating the C-terminus of the chemokine receptor CXC chemokine receptor 4 (CXCR4). WHIM mutations may potentiate CXCR4 signalling, suggesting that the United States Food and Drug Administration (FDA)-approved CXCR4 antagonist AnorMED3100 (AMD3100) (also known as Plerixafor) may be beneficial in WHIM syndrome. We have tested this at the preclinical level by comparing Chinese hamster ovary (CHO) and K562 cell lines matched for expression of recombinant wild-type CXCR4 (CXCR4WT) and the most common WHIM variant of CXCR4 (CXCR4R334X), as well as leucocytes from a WHIM patient with the CXCR4R334X mutation versus healthy controls. We found that CXCR4R334X mediated modestly increased signalling (∼2-fold) in all functional assays tested, but strongly resisted ligand-dependent down-regulation. AMD3100 was equipotent and equieffective as an antagonist at CXCR4R334X and CXCR4WT. Together, our data provide further evidence that CXCR4R334X is a gain-of-function mutation, and support clinical evaluation of AMD3100 as mechanism-based treatment in patients with WHIM syndrome.
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Affiliation(s)
- David H McDermott
- Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
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35
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Li SC, Acevedo J, Wang L, Jiang H, Luo J, Pestell RG, Loudon WG, Chang AC. Mechanisms for progenitor cell-mediated repair for ischemic heart injury. Curr Stem Cell Res Ther 2012; 7:2-14. [PMID: 21466480 PMCID: PMC6544365 DOI: 10.2174/157488812798483449] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Revised: 03/04/2011] [Accepted: 03/14/2011] [Indexed: 11/22/2022]
Abstract
Recent studies have shown that treatments involving injection of stem cells into animals with damaged cardiac tissue result in improved cardiac functionality. Clinical trials have reported conflicting results concerning the recellularization of post-infarct collagen scars. No clear mechanism has so far emerged to fully explain how injected stem cells, specifically the commonly used mesenchymal stem cells (MSC) and endothelial precursor cells (EPC), help heal a damaged heart. Clearly, these injected stem cells must survive and thrive in the hypoxic environment that results after injury for any significant repair to occur. Here we discuss how ischemic preconditioning may lead to increased tolerance of stem cells to these harsh conditions and increase their survival and clinical potential after injection. As injected cells must reach the site in numbers large enough for repair to be functionally significant, homing mechanisms involved in stem cell migration are also discussed. We review the mechanisms of action stem cells may employ once they arrive at their target destination. These possible mechanisms include that the injected stem cells (1) secrete growth factors, (2) differentiate into cardiomyocytes to recellularize damaged tissue and strengthen the post-infarct scar, (3) transdifferentiate the host cells into cardiomyocytes, and (4) induce neovascularization. Finally, we discuss that tissue engineering may provide a standardized platform technology to produce clinically applicable stem cell products with these desired mechanistic capacities.
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Affiliation(s)
- Shengwen Calvin Li
- CHOC Children's Hospital Research Institute, University of California, Irrine, Orange, 92868, USA.
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36
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Zhao Y, Mangalmurti NS, Xiong Z, Prakash B, Guo F, Stolz DB, Lee JS. Duffy antigen receptor for chemokines mediates chemokine endocytosis through a macropinocytosis-like process in endothelial cells. PLoS One 2011; 6:e29624. [PMID: 22216333 PMCID: PMC3246497 DOI: 10.1371/journal.pone.0029624] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Accepted: 12/01/2011] [Indexed: 12/26/2022] Open
Abstract
Background The Duffy antigen receptor for chemokines (DARC) shows high affinity binding to multiple inflammatory CC and CXC chemokines and is expressed by erythrocytes and endothelial cells. Recent evidence suggests that endothelial DARC facilitates chemokine transcytosis to promote neutrophil recruitment. However, the mechanism of chemokine endocytosis by DARC remains unclear. Methodology/Principal Findings We investigated the role of several endocytic pathways in DARC-mediated ligand internalization. Here we report that, although DARC co-localizes with caveolin-1 in endothelial cells, caveolin-1 is dispensable for DARC-mediated 125I-CXCL1 endocytosis as knockdown of caveolin-1 failed to inhibit ligand internalization. 125I-CXCL1 endocytosis by DARC was also independent of clathrin and flotillin-1 but required cholesterol and was, in part, inhibited by silencing Dynamin II expression.125I-CXCL1 endocytosis was inhibited by amiloride, cytochalasin D, and the PKC inhibitor Gö6976 whereas Platelet Derived Growth Factor (PDGF) enhanced ligand internalization through DARC. The majority of DARC-ligand interactions occurred on the endothelial surface, with DARC identified along plasma membrane extensions with the appearance of ruffles, supporting the concept that DARC provides a high affinity scaffolding function for surface retention of chemokines on endothelial cells. Conclusions/Significance These results show DARC-mediated chemokine endocytosis occurs through a macropinocytosis-like process in endothelial cells and caveolin-1 is dispensable for CXCL1 internalization.
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Affiliation(s)
- Yani Zhao
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Nilam S. Mangalmurti
- Pulmonary, Allergy and Critical Care Division, Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Zeyu Xiong
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Bharat Prakash
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Fengli Guo
- Department of Cell Biology and Physiology, Center for Biologic Imaging, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Donna B. Stolz
- Department of Cell Biology and Physiology, Center for Biologic Imaging, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Janet S. Lee
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- * E-mail:
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Bennett LD, Fox JM, Signoret N. Mechanisms regulating chemokine receptor activity. Immunology 2011; 134:246-56. [PMID: 21977995 PMCID: PMC3209565 DOI: 10.1111/j.1365-2567.2011.03485.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Revised: 07/04/2011] [Accepted: 07/12/2011] [Indexed: 12/21/2022] Open
Abstract
Co-ordinated movement and controlled positioning of leucocytes is key to the development, maintenance and proper functioning of the immune system. Chemokines and their receptors play an essential role in these events by mediating directed cell migration, often referred to as chemotaxis. The chemotactic property of these molecules is also thought to contribute to an array of pathologies where inappropriate recruitment of specific chemokine receptor-expressing leucocytes is observed, including cancer and inflammatory diseases. As a result, chemokine receptors have become major targets for therapeutic intervention, and during the past 15 years much research has been devoted to understanding the regulation of their biological activity. From these studies, processes which govern the availability of functional chemokine receptors at the cell surface have emerged as playing a central role. In this review, we summarize and discuss current knowledge on the molecular mechanisms contributing to the regulation of chemokine receptor surface expression, from gene transcription and protein degradation to post-translational modifications, multimerization, intracellular transport and cross-talk.
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Affiliation(s)
- Laura D Bennett
- Centre for Immunology and Infection, Department of Biology and Hull York Medical School, University of York, York, UK
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Kumar A, Kremer KN, Dominguez D, Tadi M, Hedin KE. Gα13 and Rho mediate endosomal trafficking of CXCR4 into Rab11+ vesicles upon stromal cell-derived factor-1 stimulation. THE JOURNAL OF IMMUNOLOGY 2010; 186:951-8. [PMID: 21148034 DOI: 10.4049/jimmunol.1002019] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CXCR4, like other G protein-coupled receptors, signals via heterotrimeric guanine nucleotide-binding proteins (G proteins) to regulate gene transcription, migration, development, growth, and transformation. We describe a formerly uncharacterized function of a G protein: a role in receptor trafficking. We previously showed that CXCR4 and the TCR physically associate and form a heterodimer upon stromal cell-derived factor-1 or CXCL12 (SDF-1) stimulation in human T cells to prolong ERK activation and, thereby, lead to gene upregulation and cytokine secretion. The CXCR4-TCR heterodimers occur on the cell surface and in an intracellular compartment in response to SDF-1. Neither the intracellular compartment to which the CXCR4-TCR heterodimers localize nor the mechanism for localization has been elucidated. In this article, we characterize molecular mechanisms required for postendocytic trafficking of CXCR4. Upon SDF-1 stimulation, CXCR4 localizes to Rab11(+) vesicles, a recycling compartment near the microtubule organizing center and Golgi apparatus. This trafficking requires the CXCR4 C-terminal tail domain but not the CXCR4 ubiquitination sites. The TCR also constitutively localizes to this Rab11(+) compartment. Trafficking of CXCR4 into the Rab11(+), TCR-containing endosomes requires actin polymerization. Furthermore, inhibiting Rho activation or depleting Gα13 prevented trafficking of CXCR4 into the Rab11(+) endosomes without hindering the ability of CXCR4 to endocytose. These results indicated that, upon SDF-1 treatment, Gα13 and Rho mediate the actin polymerization necessary for trafficking CXCR4 into the Rab11(+), recycling endosomal compartment, which also contains constitutively recycling TCR and, thus, CXCR4-TCR heterodimers. To our knowledge, this is the first report of Gα13 as a mediator of receptor trafficking.
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Affiliation(s)
- Ashok Kumar
- Department of Immunology, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, MN 55905, USA
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Yi L, Rosales T, Rose JJ, Chowdhury B, Chaudhury B, Knutson JR, Venkatesan S. HIV-1 Nef binds a subpopulation of MHC-I throughout its trafficking itinerary and down-regulates MHC-I by perturbing both anterograde and retrograde trafficking. J Biol Chem 2010; 285:30884-905. [PMID: 20622010 DOI: 10.1074/jbc.m110.135947] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The HIV protein Nef is thought to mediate immune evasion and promote viral persistence in part by down-regulating major histocompatibility complex class I protein (MHC-I or HLA-I) from the cell surface. Two different models have been proposed to explain this phenomenon as follows: 1) stimulation of MHC-I retrograde trafficking from and aberrant recycling to the plasma membrane, and 2) inhibition of anterograde trafficking of newly synthesized HLA-I from the endoplasmic reticulum to the plasma membrane. We show here that Nef simultaneously uses both mechanisms to down-regulate HLA-I in peripheral blood mononuclear cells or HeLa cells. Consistent with this, we found by using fluorescence correlation spectroscopy that a third of diffusing HLA-I at the endoplasmic reticulum, Golgi/trans-Golgi network, and the plasma membrane (PM) was associated with Nef. The binding of Nef was similarly avid for native HLA-I and recombinant HLA-I A2 at the PM. Nef binding to HLA-I at the PM was sensitive to specific inhibition of endocytosis. It was also attenuated by cyclodextrin disruption of PM lipid micro-domain architecture, a change that also retarded lateral diffusion and induced large clusters of HLA-I. In all, our data support a model for Nef down-regulation of HLA-I that involves both major trafficking itineraries and persistent protein-protein interactions throughout the cell.
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Affiliation(s)
- Ling Yi
- Molecular and Cell Biology Unit, Laboratory of Molecular Immunology, NIAID, Laboratory of Molecular Biophysics, NHLBI, National Institutes of Health, Bethesda, Maryland 20892, USA
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40
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Yamashiro H, Yoshizaki S, Tadaki T, Egawa K, Seo N. Stimulation of human butyrophilin 3 molecules results in negative regulation of cellular immunity. J Leukoc Biol 2010; 88:757-67. [DOI: 10.1189/jlb.0309156] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Affiliation(s)
| | - Shinji Yoshizaki
- Department of Molecular Biodefense Research, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | | | | | - Naohiro Seo
- Department of Dermatology, Hamamatsu University School of Medicine, Hamamatsu, Japan
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Sierra MI, Wright MH, Nash PD. AMSH interacts with ESCRT-0 to regulate the stability and trafficking of CXCR4. J Biol Chem 2010; 285:13990-4004. [PMID: 20159979 PMCID: PMC2859561 DOI: 10.1074/jbc.m109.061309] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Revised: 02/01/2010] [Indexed: 11/06/2022] Open
Abstract
Reversible ubiquitination is essential for the endocytic sorting and down-regulation of G protein-coupled receptors, such as the chemokine receptor CXCR4. The deubiquitinating enzyme AMSH has been implicated in the endocytic sorting of both G protein-coupled receptors and receptor-tyrosine kinases. Herein, we examine the role of AMSH in the regulation of CXCR4 stability and trafficking and characterize protein-protein interactions critical for this function. Loss of AMSH catalytic activity or depletion by RNAi results in increased steady-state levels of CXCR4 under basal conditions. Analysis of truncation and point mutation of AMSH reveal the importance of an RXXK motif for CXCR4 degradation. The RXXK motif of AMSH interacts with the SH3 domains of the STAM and Grb2 families of adaptor proteins with high affinity. Cells expressing a catalytically inactive mutant of AMSH show basal hyperubiquitination, but not increased degradation, of the ESCRT-0 components STAM1 and Hrs. This is dependent on the RXXK motif of AMSH. Ubiquitination of endocytic machinery modulates their activity, suggesting that AMSH may directly regulate endocytic adaptor protein function. This is reflected in CXCR4 trafficking and provides a mechanism by which AMSH specifies the fate of endocytosed receptors. Taken together, these studies implicate AMSH as a key modulator of receptor fate determination through its action on components of the endocytic machinery.
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Affiliation(s)
- Maria I. Sierra
- From the Ben May Department for Cancer Research, The University of Chicago, Chicago, Illinois 60637
| | - Michelle H. Wright
- From the Ben May Department for Cancer Research, The University of Chicago, Chicago, Illinois 60637
| | - Piers D. Nash
- From the Ben May Department for Cancer Research, The University of Chicago, Chicago, Illinois 60637
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42
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CCR5: From Natural Resistance to a New Anti-HIV Strategy. Viruses 2010; 2:574-600. [PMID: 21994649 PMCID: PMC3185609 DOI: 10.3390/v2020574] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2009] [Revised: 12/22/2009] [Accepted: 02/04/2010] [Indexed: 02/08/2023] Open
Abstract
The C-C chemokine receptor type 5 (CCR5) is a key player in HIV infection due to its major involvement in the infection process. Investigations into the role of the CCR5 coreceptor first focused on its binding to the virus and the molecular mechanisms leading to the entry and spread of HIV. The identification of naturally occurring CCR5 mutations has allowed scientists to address the CCR5 molecule as a promising target to prevent or limit HIV infection in vivo. Naturally occurring CCR5-specific antibodies have been found in exposed but uninfected people, and in a subset of HIV seropositive people who show long-term control of the infection. This suggests that natural autoimmunity to the CCR5 coreceptor exists and may play a role in HIV control. Such natural immunity has prompted strategies aimed at achieving anti-HIV humoral responses through CCR5 targeting, which will be described here.
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43
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Busillo JM, Armando S, Sengupta R, Meucci O, Bouvier M, Benovic JL. Site-specific phosphorylation of CXCR4 is dynamically regulated by multiple kinases and results in differential modulation of CXCR4 signaling. J Biol Chem 2010; 285:7805-17. [PMID: 20048153 DOI: 10.1074/jbc.m109.091173] [Citation(s) in RCA: 223] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The chemokine receptor CXCR4 is a widely expressed G protein-coupled receptor that has been implicated in a number of diseases including human immunodeficiency virus, cancer, and WHIM syndrome, with the latter two involving dysregulation of CXCR4 signaling. To better understand the role of phosphorylation in regulating CXCR4 signaling, tandem mass spectrometry and phospho-specific antibodies were used to identify sites of agonist-promoted phosphorylation. These studies demonstrated that Ser-321, Ser-324, Ser-325, Ser-330, Ser-339, and two sites between Ser-346 and Ser-352 were phosphorylated in HEK293 cells. We show that Ser-324/5 was rapidly phosphorylated by protein kinase C and G protein-coupled receptor kinase 6 (GRK6) upon CXCL12 treatment, whereas Ser-339 was specifically and rapidly phosphorylated by GRK6. Ser-330 was also phosphorylated by GRK6, albeit with slower kinetics. Similar results were observed in human astroglia cells, where endogenous CXCR4 was rapidly phosphorylated on Ser-324/5 by protein kinase C after CXCL12 treatment, whereas Ser-330 was slowly phosphorylated. Analysis of CXCR4 signaling in HEK293 cells revealed that calcium mobilization was primarily negatively regulated by GRK2, GRK6, and arrestin3, whereas GRK3, GRK6, and arrestin2 played a primary role in positively regulating ERK1/2 activation. In contrast, GRK2 appeared to play a negative role in ERK1/2 activation. Finally, we show that arrestin association with CXCR4 is primarily driven by the phosphorylation of far C-terminal residues on the receptor. These studies reveal that site-specific phosphorylation of CXCR4 is dynamically regulated by multiple kinases resulting in both positive and negative modulation of CXCR4 signaling.
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Affiliation(s)
- John M Busillo
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
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44
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Idiopathic CD4+ T-cell lymphocytopenia is associated with impaired membrane expression of the chemokine receptor CXCR4. Blood 2009; 115:3708-17. [PMID: 20038787 DOI: 10.1182/blood-2009-02-202796] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Idiopathic CD4(+) T-cell lymphocytopenia (ICL) is a rare acquired T-cell immunodeficiency of unknown pathogenic basis. Six adults with ICL who developed opportunistic infections were investigated using extensive immunophenotyping analysis and functional evaluation of the chemokine receptor CXCR4. For all 6 patients studied, a profound defect in CXCR4 expression was detected at the surface of CD4(+) T lymphocytes, in association with an abnormal intracellular accumulation of CXCR4 and of its natural ligand, the chemokine CXCL12. For all patients studied, CD4(+) T-cell chemotactic response toward CXCL12 was decreased, whereas sensitivity to CXCL8 was preserved. CXCR4 recovery after ligand-induced endocytosis was impaired in ICL CD4(+) T cells. Upon in vitro addition of interleukin-2 (IL-2), membrane expression of CXCR4 returned to normal levels in 5 of 6 patients, whereas intracellular accumulation of CXCR4 and CXCL12 disappeared. Upon therapeutic administration of IL-2, CD4(+) T-cell count and membrane CXCR4 expression and function improved over time in 3 of 4 patients treated. Therefore, our data indicate that ICL is associated with defective surface expression of CXCR4, which may be reversed by IL-2.
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45
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46
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O'Boyle G, Mellor P, Kirby JA, Ali S. Anti-inflammatory therapy by intravenous delivery of non-heparan sulfate-binding CXCL12. FASEB J 2009; 23:3906-16. [PMID: 19667120 PMCID: PMC2791779 DOI: 10.1096/fj.09-134643] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Interaction between chemokines and heparan sulfate (HS) is essential for leukocyte recruitment during inflammation. Previous studies have shown that a non-HS-binding mutant form of the inflammatory chemokine CCL7 can block inflammation produced by wild-type chemokines. This study examined the anti-inflammatory mechanism of a non-HS-binding mutant of the homeostatic chemokine CXCL12. Initial experiments demonstrated that mutant CXCL12 was an effective CXCR4 agonist. However, this mutant chemokine failed to promote transendothelial migration in vitro and inhibited the haptotactic response to wild-type CCL7, CXCL12, and CXCL8, and naturally occurring chemoattractants in synovial fluid from the rheumatoid synovium, including CCL2, CCL7, and CXCL8. Notably, intravenous administration of mutant CXCL12 also inhibited the recruitment of leukocytes to murine air pouches filled with wild-type CXCL12. Following intravenous administration, wild-type CXCL12 was cleared from the circulation rapidly, while the mutant chemokine persisted for >24 h. Chronic exposure to mutant CXCL12 in the circulation reduced leukocyte-surface expression of CXCR4, reduced the chemotactic response of these cells to CXCL12, and inhibited normal chemokine-mediated induction of adhesion between the alpha4beta1 integrin, VLA-4, and VCAM-1. These data demonstrate that systemic administration of non-HS-binding variants of CXCL12 can mediate a powerful anti-inflammatory effect through chemokine receptor desensitization.
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Affiliation(s)
- Graeme O'Boyle
- Applied Immunobiology and Transplantation Research Group, Institute of Cellular Medicine, Medical School, University of Newcastle, Newcastle upon Tyne, NE2 4HH UK
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47
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Inhibition of dynamin prevents CCL2-mediated endocytosis of CCR2 and activation of ERK1/2. Cell Signal 2009; 21:1748-57. [PMID: 19643177 DOI: 10.1016/j.cellsig.2009.07.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2009] [Revised: 07/16/2009] [Accepted: 07/21/2009] [Indexed: 11/20/2022]
Abstract
The magnitude and duration of G protein-coupled receptor (GPCR) signals are regulated through desensitization mechanisms. In leukocytes, ligand binding to chemokine receptors leads to Ca2+ mobilization and ERK activation through pertussis toxin-sensitive G proteins, as well as to phosphorylation of the GPCR. After interaction with the endocytic machinery (clathrin, adaptin), the adaptor beta-arrestin recognizes the phosphorylated GPCR tail and quenches signaling to receptors. The molecular mechanisms that lead to receptor endocytosis are not universal amongst the GPCR, however, and the precise spatial and temporal events in the internalization of the CCR2 chemokine receptor remain unknown. Here we show that after ligand binding, CCR2 internalizes rapidly and reaches early endosomes, and later, lysosomes. Knockdown of clathrin by RNA interference impairs CCR2 internalization, as does treatment with the dynamin inhibitor, dynasore. Our results show that CCR2 internalization uses a combination of clathrin-dependent and -independent pathways, as observed for other chemokine receptors. Moreover, the use of dynasore allowed us to confirm the existence of a dynamin-sensitive element that regulates ERK1/2 activation. Our results indicate additional complexity in the link between receptor internalization and cell signaling.
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48
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Kiss DL, Longden J, Fechner GA, Avery VM. The functional antagonist Met-RANTES: a modified agonist that induces differential CCR5 trafficking. Cell Mol Biol Lett 2009; 14:537-47. [PMID: 19448977 PMCID: PMC6275935 DOI: 10.2478/s11658-009-0017-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2008] [Accepted: 05/06/2009] [Indexed: 11/20/2022] Open
Abstract
CC chemokine receptor 5 (CCR5) is a pro-inflammatory chemokine receptor that is expressed on cells of the immune system, and specializes in cell migration in response to inflammation and tissue damage. Due to its key role in cell communication and migration, this receptor is involved in various inflammatory and autoimmune diseases, in addition to HIV infection. Met-RANTES is a modified CCR5 ligand that has previously been shown to antagonize CCR5 activation and function in response to its natural ligands in vitro. In vivo, Met-RANTES is able to reduce inflammation in models of induced inflammatory and autoimmune diseases. However, due to the fact that Met-RANTES is also capable of partial agonist activity regarding receptor signaling and internalization, it is clear that Met-RANTES does not function as a conventional receptor antagonist. To further elucidate the effect of Met-RANTES on CCR5, receptor trafficking was investigated in a CHO-CCR5-GFP cell line using the Opera confocal plate reader. The internalization response of CCR5 was quantified, and showed that Met-RANTES internalized CCR5 in a slower, less potent manner than the agonists CCL3 and CCL5. Fluorescent organelle labeling and live cell imaging showed CCL3 and CCL5 caused CCR5 to traffic through sorting endosomes, recycling endosomes and the Golgi apparatus. In contrast, Met-RANTES caused CCR5 to traffic through sorting endosomes and the Golgi apparatus in a manner that was independent of recycling endosomes. As receptor trafficking impacts on cell surface expression and the ability of the receptor to respond to more ligand, this information may indicate an alternative regulation of CCR5 by Met-RANTES that allows the modified ligand to reduce inflammation through stimulation of a pro-inflammatory receptor.
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Affiliation(s)
- Debra L. Kiss
- Discovery Biology, Eskitis Institute for Cell and Molecular Therapies, Brisbane Innovation Park, Griffith University, Don Young Road, Nathan, QLD 4111 Australia
| | - James Longden
- Discovery Biology, Eskitis Institute for Cell and Molecular Therapies, Brisbane Innovation Park, Griffith University, Don Young Road, Nathan, QLD 4111 Australia
| | - Gregory A. Fechner
- Discovery Biology, Eskitis Institute for Cell and Molecular Therapies, Brisbane Innovation Park, Griffith University, Don Young Road, Nathan, QLD 4111 Australia
| | - Vicky M. Avery
- Discovery Biology, Eskitis Institute for Cell and Molecular Therapies, Brisbane Innovation Park, Griffith University, Don Young Road, Nathan, QLD 4111 Australia
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Expression of chemokines and their receptors by human brain endothelium: implications for multiple sclerosis. J Neuropathol Exp Neurol 2009; 68:227-40. [PMID: 19225413 DOI: 10.1097/nen.0b013e318197eca7] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Leukocyte migration into the central nervous system (CNS) is mediated by chemokines expressed on CNS endothelial cell surfaces. This study investigated the production of chemokines and expression of chemokine receptors by human brain endothelial cells (HBECs) in vitro and in situ. Four chemokines (CCL2, CCL5, CXCL8, and CXCL10) were demonstrated by immunohistochemistry in endothelial cells in brain samples from patients with multiple sclerosis. CXCL8 and CCL2 were constitutively released and increased by primary HBECs and the brain endothelial cell line hCEMC/D3 in response to tumor necrosis factor and/or interferon gamma. CXCL10 and CCL5 were undetectable in resting endothelial cells but were secreted in response to these proinflammatory cytokines. Tumor necrosis factor strongly increased the production of CCL2, CCL5, and CXCL8; interferon gamma upregulated CXCL10 exclusively. CCL3 was not secreted by HBECs and seemed to be confined to astrocytes in situ. The chemokine receptors CXCR1 and CXCR3 were expressed by HBECs both in vitro and in situ; CXCR3 was upregulated in response to cytokine stimulation in vitro. In contrast, CXCR3 expression was reduced in noninflammatory (silent) multiple sclerosis lesions. The particularly high levels of CXCL10 and CXCL8 expressed by brain endothelium may contribute to the predominant TH1-type inflammatory response observed in chronic inflammatory conditions such as multiple sclerosis.
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50
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Kuscher K, Danelon G, Paoletti S, Stefano L, Schiraldi M, Petkovic V, Locati M, Gerber BO, Uguccioni M. Synergy-inducing chemokines enhance CCR2 ligand activities on monocytes. Eur J Immunol 2009; 39:1118-28. [PMID: 19291700 DOI: 10.1002/eji.200838906] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
The migration of monocytes to sites of inflammation is largely determined by their response to chemokines. Although the chemokine specificities and expression patterns of chemokine receptors are well defined, it is still a matter of debate how cells integrate the messages provided by different chemokines that are concomitantly produced in physiological or pathological situations in vivo. We present evidence for one regulatory mechanism of human monocyte trafficking. Monocytes can integrate stimuli provided by inflammatory chemokines in the presence of homeostatic chemokines. In particular, migration and cell responses could occur at much lower concentrations of the CCR2 agonists, in the presence of chemokines (CCL19 and CCL21) that per se do not act on monocytes. Binding studies on CCR2(+) cells showed that CCL19 and CCL21 do not compete with the CCR2 agonist CCL2. Furthermore, the presence of CCL19 or CCL21 could influence the degradation of CCL2 and CCL7 on cells expressing the decoy receptor D6. These findings disclose a new scenario to further comprehend the complexity of chemokine-based monocyte trafficking in a vast variety of human inflammatory disorders.
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MESH Headings
- Amino Acid Sequence
- Cell Movement/drug effects
- Cell Movement/immunology
- Chemokine CCL19/chemistry
- Chemokine CCL19/immunology
- Chemokine CCL19/pharmacology
- Chemokine CCL2/immunology
- Chemokine CCL2/pharmacology
- Chemokine CCL21/chemistry
- Chemokine CCL21/immunology
- Chemokine CCL21/pharmacology
- Chemokine CCL7/immunology
- Chemokine CCL7/pharmacology
- Chemotaxis, Leukocyte/drug effects
- Chemotaxis, Leukocyte/immunology
- Extracellular Signal-Regulated MAP Kinases/immunology
- Extracellular Signal-Regulated MAP Kinases/metabolism
- Glycosaminoglycans/immunology
- Glycosaminoglycans/metabolism
- Humans
- Inflammation/immunology
- Inflammation/metabolism
- Ligands
- Molecular Sequence Data
- Monocytes/drug effects
- Monocytes/immunology
- Monocytes/metabolism
- Phosphorylation/immunology
- Protein Structure, Tertiary
- Receptors, CCR10/immunology
- Receptors, CCR10/metabolism
- Receptors, CCR2/agonists
- Receptors, CCR2/chemistry
- Receptors, CCR2/immunology
- Receptors, CCR7/agonists
- Receptors, CCR7/chemistry
- Receptors, CCR7/immunology
- Chemokine Receptor D6
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Affiliation(s)
- Katrin Kuscher
- Institute for Research in Biomedicine, Bellinzona, Switzerland
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