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Jensen RK, Bajic G, Sen M, Springer TA, Vorup-Jensen T, Andersen GR. Complement Receptor 3 Forms a Compact High-Affinity Complex with iC3b. THE JOURNAL OF IMMUNOLOGY 2021; 206:3032-3042. [PMID: 34117107 DOI: 10.4049/jimmunol.2001208] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 04/13/2021] [Indexed: 11/19/2022]
Abstract
Complement receptor 3 (CR3, also known as Mac-1, integrin αMβ2, or CD11b/CD18) is expressed on a subset of myeloid and certain activated lymphoid cells. CR3 is essential for the phagocytosis of complement-opsonized particles such as pathogens and apoptotic or necrotic cells opsonized with the complement fragment iC3b and, to a lesser extent, C3dg. Although the interaction between the iC3b thioester domain and the ligand binding CR3 αM I-domain is structurally and functionally well characterized, the nature of additional CR3-iC3b interactions required for phagocytosis of complement-opsonized objects remains obscure. In this study, we analyzed the interaction between iC3b and the 150-kDa headpiece fragment of the CR3 ectodomain. Surface plasmon resonance experiments demonstrated a 30 nM affinity of the CR3 headpiece for iC3b compared with 515 nM for the iC3b thioester domain, whereas experiments monitoring binding of iC3b to CR3-expressing cells suggested an affinity of 50 nM for the CR3-iC3b interaction. Small angle x-ray scattering analysis revealed that iC3b adopts an extended but preferred conformation in solution. Upon interaction with CR3, iC3b rearranges to form a compact receptor-ligand complex. Overall, the data suggest that the iC3b-CR3 interaction is of high affinity and relies on minor contacts formed between CR3 and regions outside the iC3b thioester domain. Our results rationalize the more efficient phagocytosis elicited by iC3b than by C3dg and pave the way for the development of specific therapeutics for the treatment of inflammatory and neurodegenerative diseases that do not interfere with the recognition of noncomplement CR3 ligands.
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Affiliation(s)
- Rasmus K Jensen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Goran Bajic
- Laboratory of Molecular Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA.,Department of Pediatrics, Harvard Medical School, Boston, MA.,Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Mehmet Sen
- Department of Biology and Biochemistry, University of Houston, Houston, TX
| | - Timothy A Springer
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA.,Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA; and
| | | | - Gregers R Andersen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark;
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2
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Lamers C, Plüss CJ, Ricklin D. The Promiscuous Profile of Complement Receptor 3 in Ligand Binding, Immune Modulation, and Pathophysiology. Front Immunol 2021; 12:662164. [PMID: 33995387 PMCID: PMC8118671 DOI: 10.3389/fimmu.2021.662164] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 04/12/2021] [Indexed: 12/19/2022] Open
Abstract
The β2-integrin receptor family has a broad spectrum of physiological functions ranging from leukocyte adhesion, cell migration, activation, and communication to the phagocytic uptake of cells and particles. Among the members of this family, complement receptor 3 (CR3; CD11b/CD18, Mac-1, αMβ2) is particularly promiscuous in its functional profile and ligand selectivity. There are close to 100 reported structurally unrelated ligands for CR3, and while many ligands appear to cluster at the αMI domain, molecular details about binding modes remain largely elusive. The versatility of CR3 is reflected in its functional portfolio, which includes prominent roles in the removal of invaders and cell debris, induction of tolerance and synaptic pruning, and involvement in the pathogenesis of numerous autoimmune and chronic inflammatory pathologies. While CR3 is an interesting therapeutic target for immune modulation due to these known pathophysiological associations, drug development efforts are limited by concerns of potential interference with host defense functions and, most importantly, an insufficient molecular understanding of the interplay between ligand binding and functional impact. Here, we provide a systematic summary of the various interaction partners of CR3 with a focus on binding mechanisms and functional implications. We also discuss the roles of CR3 as an immune receptor in health and disease, as an activation marker in research and diagnostics, and as a therapeutic target.
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Affiliation(s)
- Christina Lamers
- Molecular Pharmacy Unit, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
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3
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Lokki AI, Teirilä L, Triebwasser M, Daly E, Bhattacharjee A, Uotila L, Llort Asens M, Kurki MI, Perola M, Auro K, Salmon JE, Daly M, Atkinson JP, Laivuori H, Fagerholm S, Meri S. Dysfunction of complement receptors CR3 (CD11b/18) and CR4 (CD11c/18) in pre-eclampsia: a genetic and functional study. BJOG 2021; 128:1282-1291. [PMID: 33539617 DOI: 10.1111/1471-0528.16660] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/01/2020] [Indexed: 12/11/2022]
Abstract
OBJECTIVE To study genetic variants and their function within genes coding for complement receptors in pre-eclampsia. DESIGN A case-control study. SETTING Pre-eclampsia is a common vascular disease of pregnancy. The clearance of placenta-derived material is one of the functions of the complement system in pregnancy. POPULATION We genotyped 500 women with pre-eclamptic pregnancies and 190 pregnant women without pre-eclampsia, as controls, from the FINNPEC cohort, and 122 women with pre-eclamptic pregnancies and 1905 controls from the national FINRISK cohort. METHODS The functional consequences of genotypes discovered by targeted exomic sequencing were explored by analysing the binding of the main ligand iC3b to mutated CR3 or CR4, which were transiently expressed on the surface of COS-1 cells. MAIN OUTCOME MEASURES Allele frequencies were compared between pre-eclamptic pregnancies and controls in genetic studies. The functional consequences of selected variants were measured by binding assays. RESULTS The most significantly pre-eclampsia-linked CR3 variant M441K (P = 4.27E-4, OR = 1.401, 95% CI = 1.167-1.682) displayed a trend of increased adhesion to iC3b (P = 0.051). The CR4 variant A251T was found to enhance the adhesion of CR4 to iC3b, whereas W48R resulted in a decrease of the binding of CR4 to iC3b. CONCLUSIONS Results suggest that changes in complement-facilitated phagocytosis are associated with pre-eclampsia. Further studies are needed to ascertain whether aberrant CR3 and CR4 activity leads to altered pro- and anti-inflammatory cytokine responses in individuals carrying the associated variants, and the role of these receptors in pre-eclampsia pathogenesis. TWEETABLE ABSTRACT Genetic variants of complement receptors CR3 and CR4 have functional consequences that are associated with pre-eclampsia.
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Affiliation(s)
- A I Lokki
- Translational Immunology Research Program, Research Programs Unit, University of Helsinki, Helsinki, Finland.,Department of Obstetrics and Gynecology, Faculty of Medicine and Health Technology, Tampere University Hospital, Tampere University, Tampere, Finland
| | - L Teirilä
- Translational Immunology Research Program, Research Programs Unit, University of Helsinki, Helsinki, Finland.,Bacteriology and immunology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - M Triebwasser
- Department of Medicine, Division of Rheumatology, Washington University School of Medicine, Saint Louis, MO, USA
| | - E Daly
- Hospital and Harvard Medical School, Boston, MA, USA
| | - A Bhattacharjee
- Herantis Pharma Plc, Espoo, Finland.,Neuroscience Center, HiLife, University of Helsinki, Helsinki, Finland
| | - L Uotila
- Research Services, University of Helsinki, Helsinki, Finland
| | - M Llort Asens
- Molecular and Integrative Biosciences Research Program, Faculty of Bio- and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - M I Kurki
- Neurosurgery of Neuro Center, Kuopio University Hospital, Finland.,Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - M Perola
- Department of Health, National Institute for Health and Welfare, Helsinki, Finland
| | - K Auro
- Department of Government Services, National Institute for Health and Welfare, Helsinki, Finland
| | - J E Salmon
- Hospital for Special Surgery-Weill Cornell Medicine, Department of Medicine, New York, NY, USA
| | - M Daly
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA, USA.,Institute for Molecular Medicine Finland, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - J P Atkinson
- Department of Medicine, Division of Rheumatology, Washington University School of Medicine, Saint Louis, MO, USA
| | - H Laivuori
- Department of Obstetrics and Gynecology, Faculty of Medicine and Health Technology, Tampere University Hospital, Tampere University, Tampere, Finland.,Institute for Molecular Medicine Finland, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland.,Medical and Clinical Genetics, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - S Fagerholm
- Molecular and Integrative Biosciences Research Program, Faculty of Bio- and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - S Meri
- Translational Immunology Research Program, Research Programs Unit, University of Helsinki, Helsinki, Finland.,Bacteriology and immunology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
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- Medical and Clinical Genetics, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
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4
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Vorup-Jensen T, Jensen RK. Structural Immunology of Complement Receptors 3 and 4. Front Immunol 2018; 9:2716. [PMID: 30534123 PMCID: PMC6275225 DOI: 10.3389/fimmu.2018.02716] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Accepted: 11/05/2018] [Indexed: 01/10/2023] Open
Abstract
Complement receptors (CR) 3 and 4 belong to the family of beta-2 (CD18) integrins. CR3 and CR4 are often co-expressed in the myeloid subsets of leukocytes, but they are also found in NK cells and activated T and B lymphocytes. The heterodimeric ectodomain undergoes considerable conformational change in order to switch the receptor from a structurally bent, ligand-binding in-active state into an extended, ligand-binding active state. CR3 binds the C3d fragment of C3 in a way permitting CR2 also to bind concomitantly. This enables a hand-over of complement-opsonized antigens from the cell surface of CR3-expressing macrophages to the CR2-expressing B lymphocytes, in consequence acting as an antigen presentation mechanism. As a more enigmatic part of their functions, both CR3 and CR4 bind several structurally unrelated proteins, engineered peptides, and glycosaminoglycans. No consensus motif in the proteinaceous ligands has been established. Yet, the experimental evidence clearly suggest that the ligands are primarily, if not entirely, recognized by a single site within the receptors, namely the metal-ion dependent adhesion site (MIDAS). Comparison of some recent identified ligands points to CR3 as inclined to bind positively charged species, while CR4, by contrast, binds strongly negative-charged species, in both cases with the critical involvement of deprotonated, acidic groups as ligands for the Mg2+ ion in the MIDAS. These properties place CR3 and CR4 firmly within the realm of modern molecular medicine in several ways. The expression of CR3 and CR4 in NK cells was recently demonstrated to enable complement-dependent cell cytotoxicity toward antibody-coated cancer cells as part of biological therapy, constituting a significant part of the efficacy of such treatment. With the flexible principles of ligand recognition, it is also possible to propose a response of CR3 and CR4 to existing medicines thereby opening a possibility of drug repurposing to influence the function of these receptors. Here, from advances in the structural and cellular immunology of CR3 and CR4, we review insights on their biochemistry and functions in the immune system.
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Affiliation(s)
- Thomas Vorup-Jensen
- Biophysical Immunology Laboratory, Department of Biomedicine, Aarhus University, Aarhus, Denmark.,Interdisciplinary Nanoscience Center, Aarhus University, Aarhus, Denmark
| | - Rasmus Kjeldsen Jensen
- Department of Molecular Biology and Genetics-Structural Biology, Aarhus University, Aarhus, Denmark
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5
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Wolf D, Anto-Michel N, Blankenbach H, Wiedemann A, Buscher K, Hohmann JD, Lim B, Bäuml M, Marki A, Mauler M, Duerschmied D, Fan Z, Winkels H, Sidler D, Diehl P, Zajonc DM, Hilgendorf I, Stachon P, Marchini T, Willecke F, Schell M, Sommer B, von Zur Muhlen C, Reinöhl J, Gerhardt T, Plow EF, Yakubenko V, Libby P, Bode C, Ley K, Peter K, Zirlik A. A ligand-specific blockade of the integrin Mac-1 selectively targets pathologic inflammation while maintaining protective host-defense. Nat Commun 2018; 9:525. [PMID: 29410422 PMCID: PMC5802769 DOI: 10.1038/s41467-018-02896-8] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 01/05/2018] [Indexed: 12/22/2022] Open
Abstract
Integrin-based therapeutics have garnered considerable interest in the medical treatment of inflammation. Integrins mediate the fast recruitment of monocytes and neutrophils to the site of inflammation, but are also required for host defense, limiting their therapeutic use. Here, we report a novel monoclonal antibody, anti-M7, that specifically blocks the interaction of the integrin Mac-1 with its pro-inflammatory ligand CD40L, while not interfering with alternative ligands. Anti-M7 selectively reduces leukocyte recruitment in vitro and in vivo. In contrast, conventional anti-Mac-1 therapy is not specific and blocks a broad repertoire of integrin functionality, inhibits phagocytosis, promotes apoptosis, and fuels a cytokine storm in vivo. Whereas conventional anti-integrin therapy potentiates bacterial sepsis, bacteremia, and mortality, a ligand-specific intervention with anti-M7 is protective. These findings deepen our understanding of ligand-specific integrin functions and open a path for a new field of ligand-targeted anti-integrin therapy to prevent inflammatory conditions.
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Affiliation(s)
- Dennis Wolf
- Cardiology and Angiology I, University Heart Center, and Medical Faculty, University of Freiburg, Freiburg, 79106, Germany.,Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA, 92037, USA
| | - Nathaly Anto-Michel
- Cardiology and Angiology I, University Heart Center, and Medical Faculty, University of Freiburg, Freiburg, 79106, Germany
| | - Hermann Blankenbach
- Cardiology and Angiology I, University Heart Center, and Medical Faculty, University of Freiburg, Freiburg, 79106, Germany
| | - Ansgar Wiedemann
- Cardiology and Angiology I, University Heart Center, and Medical Faculty, University of Freiburg, Freiburg, 79106, Germany
| | - Konrad Buscher
- Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA, 92037, USA
| | - Jan David Hohmann
- Atherothrombosis and Vascular Biology, Baker Heart and Diabetes Institute, Melbourne, 8008, VIC, Australia
| | - Bock Lim
- Atherothrombosis and Vascular Biology, Baker Heart and Diabetes Institute, Melbourne, 8008, VIC, Australia
| | - Marina Bäuml
- Cardiology and Angiology I, University Heart Center, and Medical Faculty, University of Freiburg, Freiburg, 79106, Germany
| | - Alex Marki
- Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA, 92037, USA
| | - Maximilian Mauler
- Cardiology and Angiology I, University Heart Center, and Medical Faculty, University of Freiburg, Freiburg, 79106, Germany
| | - Daniel Duerschmied
- Cardiology and Angiology I, University Heart Center, and Medical Faculty, University of Freiburg, Freiburg, 79106, Germany
| | - Zhichao Fan
- Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA, 92037, USA
| | - Holger Winkels
- Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA, 92037, USA
| | - Daniel Sidler
- Division of Nephrology, Inselspital, Bern University Hospital, Bern, 3010, Switzerland
| | - Philipp Diehl
- Cardiology and Angiology I, University Heart Center, and Medical Faculty, University of Freiburg, Freiburg, 79106, Germany
| | - Dirk M Zajonc
- Division of Cell Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA, 92037, USA
| | - Ingo Hilgendorf
- Cardiology and Angiology I, University Heart Center, and Medical Faculty, University of Freiburg, Freiburg, 79106, Germany
| | - Peter Stachon
- Cardiology and Angiology I, University Heart Center, and Medical Faculty, University of Freiburg, Freiburg, 79106, Germany
| | - Timoteo Marchini
- Cardiology and Angiology I, University Heart Center, and Medical Faculty, University of Freiburg, Freiburg, 79106, Germany
| | - Florian Willecke
- Cardiology and Angiology I, University Heart Center, and Medical Faculty, University of Freiburg, Freiburg, 79106, Germany
| | - Maximilian Schell
- Cardiology and Angiology I, University Heart Center, and Medical Faculty, University of Freiburg, Freiburg, 79106, Germany.,Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA, 92037, USA
| | - Björn Sommer
- Neurosurgery, Medical Faculty of the University of Erlangen, Erlangen, 91054, Germany
| | - Constantin von Zur Muhlen
- Cardiology and Angiology I, University Heart Center, and Medical Faculty, University of Freiburg, Freiburg, 79106, Germany
| | - Jochen Reinöhl
- Cardiology and Angiology I, University Heart Center, and Medical Faculty, University of Freiburg, Freiburg, 79106, Germany
| | - Teresa Gerhardt
- Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA, 92037, USA
| | - Edward F Plow
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44195, USA
| | - Valentin Yakubenko
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44195, USA
| | - Peter Libby
- Brigham and Women's Hospital, Cardiovascular Medicine, Harvard Medical School, Boston, MA, 02115, USA
| | - Christoph Bode
- Cardiology and Angiology I, University Heart Center, and Medical Faculty, University of Freiburg, Freiburg, 79106, Germany
| | - Klaus Ley
- Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA, 92037, USA
| | - Karlheinz Peter
- Atherothrombosis and Vascular Biology, Baker Heart and Diabetes Institute, Melbourne, 8008, VIC, Australia.
| | - Andreas Zirlik
- Cardiology and Angiology I, University Heart Center, and Medical Faculty, University of Freiburg, Freiburg, 79106, Germany
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6
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Erdei A, Sándor N, Mácsik-Valent B, Lukácsi S, Kremlitzka M, Bajtay Z. The versatile functions of complement C3-derived ligands. Immunol Rev 2017; 274:127-140. [PMID: 27782338 DOI: 10.1111/imr.12498] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The complement system is a major component of immune defense. Activation of the complement cascade by foreign substances and altered self-structures may lead to the elimination of the activating agent, and during the enzymatic cascade, several biologically active fragments are generated. Most immune regulatory effects of complement are mediated by the activation products of C3, the central component. The indispensable role of C3 in opsonic phagocytosis as well as in the regulation of humoral immune response is known for long, while the involvement of complement in T-cell biology have been revealed in the past few years. In this review, we discuss the immune modulatory functions of C3-derived fragments focusing on their role in processes which have not been summarized so far. The importance of locally synthesized complement will receive special emphasis, as several immunological processes take place in tissues, where hepatocyte-derived complement components might not be available at high concentrations. We also aim to call the attention to important differences between human and mouse systems regarding C3-mediated processes.
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Affiliation(s)
- Anna Erdei
- Department of Immunology, Eötvös Loránd University, Budapest, Hungary. , .,MTA-ELTE Immunology Research Group, Budapest, Eötvös Loránd University, Budapest, Hungary. ,
| | - Noémi Sándor
- MTA-ELTE Immunology Research Group, Budapest, Eötvös Loránd University, Budapest, Hungary
| | | | - Szilvia Lukácsi
- Department of Immunology, Eötvös Loránd University, Budapest, Hungary
| | - Mariann Kremlitzka
- MTA-ELTE Immunology Research Group, Budapest, Eötvös Loránd University, Budapest, Hungary
| | - Zsuzsa Bajtay
- Department of Immunology, Eötvös Loránd University, Budapest, Hungary
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7
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Distinct recognition of complement iC3b by integrins α Xβ 2 and α Mβ 2. Proc Natl Acad Sci U S A 2017; 114:3403-3408. [PMID: 28292891 DOI: 10.1073/pnas.1620881114] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Recognition by the leukocyte integrins αXβ2 and αMβ2 of complement iC3b-opsonized targets is essential for effector functions including phagocytosis. The integrin-binding sites on iC3b remain incompletely characterized. Here, we describe negative-stain electron microscopy and biochemical studies of αXβ2 and αMβ2 in complex with iC3b. Despite high homology, the two integrins bind iC3b at multiple distinct sites. αXβ2 uses the αX αI domain to bind iC3b on its C3c moiety at one of two sites: a major site at the interface between macroglobulin (MG) 3 and MG4 domains, and a less frequently used site near the C345C domain. In contrast, αMβ2 uses its αI domain to bind iC3b at the thioester domain and simultaneously interacts through a region near the αM β-propeller and β2 βI domain with a region of the C3c moiety near the C345C domain. Remarkably, there is no overlap between the primary binding site of αXβ2 and the binding site of αMβ2 on iC3b. Distinctive binding sites on iC3b by integrins αXβ2 and αMβ2 may be biologically beneficial for leukocytes to more efficiently capture opsonized pathogens and to avoid subversion by pathogen factors.
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8
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Jensen MR, Bajic G, Zhang X, Laustsen AK, Koldsø H, Skeby KK, Schiøtt B, Andersen GR, Vorup-Jensen T. Structural Basis for Simvastatin Competitive Antagonism of Complement Receptor 3. J Biol Chem 2016; 291:16963-76. [PMID: 27339893 DOI: 10.1074/jbc.m116.732222] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Indexed: 01/08/2023] Open
Abstract
The complement system is an important part of the innate immune response to infection but may also cause severe complications during inflammation. Small molecule antagonists to complement receptor 3 (CR3) have been widely sought, but a structural basis for their mode of action is not available. We report here on the structure of the human CR3 ligand-binding I domain in complex with simvastatin. Simvastatin targets the metal ion-dependent adhesion site of the open, ligand-binding conformation of the CR3 I domain by direct contact with the chelated Mg(2+) ion. Simvastatin antagonizes I domain binding to the complement fragments iC3b and C3d but not to intercellular adhesion molecule-1. By virtue of the I domain's wide distribution in binding kinetics to ligands, it was possible to identify ligand binding kinetics as discriminator for simvastatin antagonism. In static cellular experiments, 15-25 μm simvastatin reduced adhesion by K562 cells expressing recombinant CR3 and by primary human monocytes, with an endogenous expression of this receptor. Application of force to adhering monocytes potentiated the effects of simvastatin where only a 50-100 nm concentration of the drug reduced the adhesion by 20-40% compared with untreated cells. The ability of simvastatin to target CR3 in its ligand binding-activated conformation is a novel mechanism to explain the known anti-inflammatory effects of this compound, in particular because this CR3 conformation is found in pro-inflammatory environments. Our report points to new designs of CR3 antagonists and opens new perspectives and identifies druggable receptors from characterization of the ligand binding kinetics in the presence of antagonists.
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Affiliation(s)
| | - Goran Bajic
- Molecular Biology and Genetics, and the Lundbeck Foundation Nanomedicine Center for Individualized Management of Tissue Damage and Regeneration (LUNA), and
| | | | | | - Heidi Koldsø
- Chemistry, the Interdisciplinary Nanoscience Center (iNANO), the Center for Insoluble Protein Structures (inSPIN)
| | - Katrine Kirkeby Skeby
- Chemistry, the Interdisciplinary Nanoscience Center (iNANO), the Center for Insoluble Protein Structures (inSPIN)
| | - Birgit Schiøtt
- Chemistry, the Interdisciplinary Nanoscience Center (iNANO), the Center for Insoluble Protein Structures (inSPIN)
| | - Gregers R Andersen
- Molecular Biology and Genetics, and the Lundbeck Foundation Nanomedicine Center for Individualized Management of Tissue Damage and Regeneration (LUNA), and
| | - Thomas Vorup-Jensen
- From the Departments of Biomedicine, the Lundbeck Foundation Nanomedicine Center for Individualized Management of Tissue Damage and Regeneration (LUNA), and the Interdisciplinary Nanoscience Center (iNANO), the MEMBRANES Research Center, Aarhus University, DK-8000 Aarhus C, Denmark
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9
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Osicka R, Osickova A, Hasan S, Bumba L, Cerny J, Sebo P. Bordetella adenylate cyclase toxin is a unique ligand of the integrin complement receptor 3. eLife 2015; 4:e10766. [PMID: 26650353 PMCID: PMC4755762 DOI: 10.7554/elife.10766] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 12/09/2015] [Indexed: 12/24/2022] Open
Abstract
Integrins are heterodimeric cell surface adhesion and signaling receptors that are essential for metazoan existence. Some integrins contain an I-domain that is a major ligand binding site. The ligands preferentially engage the active forms of the integrins and trigger signaling cascades that alter numerous cell functions. Here we found that the adenylate cyclase toxin (CyaA), a key virulence factor of the whooping cough agent Bordetella pertussis, preferentially binds an inactive form of the integrin complement receptor 3 (CR3), using a site outside of its I-domain. CyaA binding did not trigger downstream signaling of CR3 in human monocytes and CyaA-catalyzed elevation of cAMP effectively blocked CR3 signaling initiated by a natural ligand. This unprecedented type of integrin-ligand interaction distinguishes CyaA from all other known ligands of the I-domain-containing integrins and provides a mechanistic insight into the previously observed central role of CyaA in the pathogenesis of B. pertussis.
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Affiliation(s)
- Radim Osicka
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Adriana Osickova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic.,Department of Biochemistry, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Shakir Hasan
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Ladislav Bumba
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Jiri Cerny
- Institute of Biotechnology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Peter Sebo
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
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10
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Structural insight on the recognition of surface-bound opsonins by the integrin I domain of complement receptor 3. Proc Natl Acad Sci U S A 2013; 110:16426-31. [PMID: 24065820 DOI: 10.1073/pnas.1311261110] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Complement receptors (CRs), expressed notably on myeloid and lymphoid cells, play an essential function in the elimination of complement-opsonized pathogens and apoptotic/necrotic cells. In addition, these receptors are crucial for the cross-talk between the innate and adaptive branches of the immune system. CR3 (also known as Mac-1, integrin αMβ2, or CD11b/CD18) is expressed on all macrophages and recognizes iC3b on complement-opsonized objects, enabling their phagocytosis. We demonstrate that the C3d moiety of iC3b harbors the binding site for the CR3 αI domain, and our structure of the C3d:αI domain complex rationalizes the CR3 selectivity for iC3b. Based on extensive structural analysis, we suggest that the choice between a ligand glutamate or aspartate for coordination of a receptor metal ion-dependent adhesion site-bound metal ion is governed by the secondary structure of the ligand. Comparison of our structure to the CR2:C3d complex and the in vitro formation of a stable CR3:C3d:CR2 complex suggests a molecular mechanism for the hand-over of CR3-bound immune complexes from macrophages to CR2-presenting cells in lymph nodes.
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Zhou M, Li LH, Peng H, Li R, Feng CC, Xu WD, Leng RX, Pan HF, Ye DQ. Decreased ITGAM and FcγRIIIA mRNA expression levels in peripheral blood mononuclear cells from patients with systemic lupus erythematosus. Clin Exp Med 2013; 14:269-74. [PMID: 23708937 DOI: 10.1007/s10238-013-0240-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Accepted: 05/10/2013] [Indexed: 11/29/2022]
Abstract
Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease with complex genetic predisposing factors involved. ITGAM and FCγRIIIA are two kinds of immune complex clearance molecules. The variants in ITGAM and FCγRIIIA genes have been confirmed to be associated with SLE. The aim of this study is to investigate the association of mRNA expression levels of ITGAM and FCγRIIIA with SLE. Real-time transcription-polymerase chain reaction analysis (RT-PCR) was used to determine the expression levels of ITGAM and FCγRIIIA mRNA in peripheral blood mononuclear cells (PBMC) from 60 patients with SLE and 60 healthy controls. Flow cytometry was used to measure the expression level of ITGAM and FcγRIIIA from 30 SLE patients and 30 healthy controls. The expression levels of ITGAM mRNA was significantly decreased in SLE patients compared with healthy controls (P = 0.007). Patients with arthritis had higher ITGAM mRNA level than those without arthritis (P = 0.029). The expression level of FCγRIIIA mRNA in SLE patients was significantly lower than that of healthy controls (P = 0.001). Decreased expression level of FCγRIIIA mRNA was also found in patients with LN compared with those without LN (P = 0.015). The level of ITGAM mRNA in patients with anti-SSB positive, anti-RNP positive, complement reduction and increased IgG was significantly reduced. No significant correlation was found between ITGAM and FcγRIIIA mRNA expression level in SLE patients (r = -0.019, P = 0.882). Expression of ITGAM protein in T cells, neutrophil and monocyte of SLE patients was significantly lower than healthy controls (P < 0.05). For FcγRIIIA protein expression in monocyte and NK cells, there were no significant difference between SLE patients and healthy controls (P > 0.05). The altered expression levels of ITGAM and FCγRIIIA mRNA in SLE patients and their correlations with clinical data suggest that ITGAM and FCγRIIIA may play a role in this disease.
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Affiliation(s)
- Mo Zhou
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, 81 Meishan Road, Hefei, 230032, Anhui, People's Republic of China
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Phagocytosis is the main CR3-mediated function affected by the lupus-associated variant of CD11b in human myeloid cells. PLoS One 2013; 8:e57082. [PMID: 23451151 PMCID: PMC3579793 DOI: 10.1371/journal.pone.0057082] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 01/17/2013] [Indexed: 11/19/2022] Open
Abstract
The CD11b/CD18 integrin (complement receptor 3, CR3) is a surface receptor on monocytes, neutrophils, macrophages and dendritic cells that plays a crucial role in several immunological processes including leukocyte extravasation and phagocytosis. The minor allele of a non-synonymous CR3 polymorphism (rs1143679, conversation of arginine to histidine at position 77: R77H) represents one of the strongest genetic risk factor in human systemic lupus erythematosus, with heterozygosity (77R/H) being the most common disease associated genotype. Homozygosity for the 77H allele has been reported to reduce adhesion and phagocytosis in human monocytes and monocyte-derived macrophages, respectively, without affecting surface expression of CD11b. Herein we comprehensively assessed the influence of R77H on different CR3-mediated activities in monocytes, neutrophils, macrophages and dendritic cells. R77H did not alter surface expression of CD11b including its active form in any of these cell types. Using two different iC3b-coated targets we found that the uptake by heterozygous 77R/H macrophages, monocytes and neutrophils was significantly reduced compared to 77R/R cells. Allele-specific transduced immortalized macrophage cell lines demonstrated that the minor allele, 77H, was responsible for the impaired phagocytosis. R77H did not affect neutrophil adhesion, neutrophil transmigration in vivo or Toll-like receptor 7/8-mediated cytokine release by monocytes or dendritic cells with or without CR3 pre-engagement by iC3b-coated targets. Our findings demonstrate that the reduction in CR3-mediated phagocytosis associated with the 77H CD11b variant is not macrophage-restricted but demonstrable in other CR3-expressing professional phagocytic cells. The association between 77H and susceptibility to systemic lupus erythematosus most likely relates to impaired waste disposal, a key component of lupus pathogenesis.
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Rhodes B, Fürnrohr BG, Roberts AL, Tzircotis G, Schett G, Spector TD, Vyse TJ. The rs1143679 (R77H) lupus associated variant of ITGAM (CD11b) impairs complement receptor 3 mediated functions in human monocytes. Ann Rheum Dis 2012; 71:2028-34. [PMID: 22586164 PMCID: PMC3488763 DOI: 10.1136/annrheumdis-2012-201390] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVES The rs1143679 variant of ITGAM, encoding the R77H variant of CD11b (part of complement receptor 3; CR3), is among the strongest genetic susceptibility effects in human systemic lupus erythematosus (SLE). The authors aimed to demonstrate R77H function in ex-vivo human cells. METHODS Monocytes/monocyte-derived macrophages from healthy volunteers homozygous for either wild type (WT) or 77H CD11b were studied. The genotype-specific expression of CD11b, and CD11b activation using conformation-specific antibodies were measured. Genotype-specific differences in iC3b-mediated phagocytosis, adhesion to a range of ligands and the secretion of cytokines following CR3 ligation were studied. The functionality of R77H was confirmed by replicating findings in COS7 cells expressing variant-specific CD11b. RESULTS No genotype-specific difference in CD11b expression or in the expression of CD11b activation epitopes was observed. A 31% reduction was observed in the phagocytosis of iC3b opsonised sheep erythrocytes (sRBC(iC3b)) by 77H cells (p=0.003) and reduced adhesion to a range of ligands: notably a 24% reduction in adhesion to iC3b (p=0.014). In transfected COS7 cells, a 42% reduction was observed in phagocytosis by CD11b (77H)-expressing cells (p=0.004). A significant inhibition was seen in the release of Toll-like receptor 7/8-induced pro-inflammatory cytokines from WT monocytes when CR3 was pre-engaged using sRBC(iC3b), but no inhibition in 77H monocytes resulting in a significant difference between genotypes (interleukin (IL)-1β p=0.030; IL-6 p=0.029; tumour necrosis factor alpha p=0.027). CONCLUSIONS The R77H variant impairs a broad range of CR3 effector functions in human monocytes. This study discusses how perturbation of this pathway may predispose to SLE.
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Affiliation(s)
- Benjamin Rhodes
- Genetics and Molecular Medicine and Immunology, Infection and Inflammatory Disease, King’s College London, London, UK
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Kim K, Brown EE, Choi CB, Alarcón-Riquelme ME, Kelly JA, Glenn SB, Ojwang JO, Adler A, Lee HS, Boackle SA, Criswell LA, Alarcón GS, Edberg JC, Stevens AM, Jacob CO, Gilkeson GS, Kamen DL, Tsao BP, Anaya JM, Guthridge JM, Nath SK, Richardson B, Sawalha AH, Kang YM, Shim SC, Suh CH, Lee SK, Kim CS, Merrill JT, Petri M, Ramsey-Goldman R, Vilá LM, Niewold TB, Martin J, Pons-Estel BA, Vyse TJ, Freedman BI, Moser KL, Gaffney PM, Williams A, Comeau M, Reveille JD, James JA, Scofield RH, Langefeld CD, Kaufman KM, Harley JB, Kang C, Kimberly RP, Bae SC. Variation in the ICAM1-ICAM4-ICAM5 locus is associated with systemic lupus erythematosus susceptibility in multiple ancestries. Ann Rheum Dis 2012; 71:1809-14. [PMID: 22523428 DOI: 10.1136/annrheumdis-2011-201110] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
OBJECTIVE Systemic lupus erythematosus (SLE; OMIM 152700) is a chronic autoimmune disease for which the aetiology includes genetic and environmental factors. ITGAM, integrin α(M) (complement component 3 receptor 3 subunit) encoding a ligand for intracellular adhesion molecule (ICAM) proteins, is an established SLE susceptibility locus. This study aimed to evaluate the independent and joint effects of genetic variations in the genes that encode ITGAM and ICAM. METHODS The authors examined several markers in the ICAM1-ICAM4-ICAM5 locus on chromosome 19p13 and the single ITGAM polymorphism (rs1143679) using a large-scale case-control study of 17 481 unrelated participants from four ancestry populations. The single-marker association and gene-gene interaction were analysed for each ancestry, and a meta-analysis across the four ancestries was performed. RESULTS The A-allele of ICAM1-ICAM4-ICAM5 rs3093030, associated with elevated plasma levels of soluble ICAM1, and the A-allele of ITGAM rs1143679 showed the strongest association with increased SLE susceptibility in each of the ancestry populations and the trans-ancestry meta-analysis (OR(meta)=1.16, 95% CI 1.11 to 1.22; p=4.88×10(-10) and OR(meta)=1.67, 95% CI 1.55 to 1.79; p=3.32×10(-46), respectively). The effect of the ICAM single-nucleotide polymorphisms (SNPs) was independent of the effect of the ITGAM SNP rs1143679, and carriers of both ICAM rs3093030-AA and ITGAM rs1143679-AA had an OR of 4.08 compared with those with no risk allele in either SNP (95% CI 2.09 to 7.98; p=3.91×10(-5)). CONCLUSION These findings are the first to suggest that an ICAM-integrin-mediated pathway contributes to susceptibility to SLE.
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Affiliation(s)
- Kwangwoo Kim
- 1Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Korea
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Abstract
Integrin α(X)β(2) functions as complement receptor for iC3b and mediates recognition and phagocytosis of pathogens. We used negative-stain EM to examine the α(X)β(2) interaction with iC3b. EM class averages of α(X)β(2) in complex with iC3b define the binding sites on both the integrin and iC3b. iC3b contains C3c and thioester domain moieties linked by a long flexible linker. The binding site is on the key ring of the C3c moiety, at the interface between the MG3 and MG4 domains. Similar complexes are seen between α(X)β(2) and the C3c fragment. α(X)β(2) binds through the α(X) αI domain, on the face known to bear the metal ion-dependent adhesion site, at the opposite end of the αI domain from its site of insertion in the β-propeller domain.
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Hughes T, Adler A, Kelly JA, Kaufman KM, Williams A, Langefeld CD, Brown EE, Alarcón GS, Kimberly RP, Edberg JC, Ramsey-Goldman R, Petri M, Boackle SA, Stevens AM, Reveille JD, Sanchez E, Martin J, Niewold TB, Vilá LM, Scofield RH, Gilkeson GS, Gaffney PM, Criswell LA, Moser KL, Merrill JT, Jacob CO, Tsao BP, James JA, Vyse TJ, Alarcón-Riquelme ME, Harley JB, Richardson BC, Sawalha AH. Evidence for gene-gene epistatic interactions among susceptibility loci for systemic lupus erythematosus. ARTHRITIS AND RHEUMATISM 2012; 64:485-92. [PMID: 21952918 PMCID: PMC3268866 DOI: 10.1002/art.33354] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
OBJECTIVE Several confirmed genetic susceptibility loci for lupus have been described. To date, no clear evidence for genetic epistasis in lupus has been established. The aim of this study was to test for gene-gene interactions in a number of known lupus susceptibility loci. METHODS Eighteen single-nucleotide polymorphisms tagging independent and confirmed lupus susceptibility loci were genotyped in a set of 4,248 patients with lupus and 3,818 normal healthy control subjects of European descent. Epistasis was tested by a 2-step approach using both parametric and nonparametric methods. The false discovery rate (FDR) method was used to correct for multiple testing. RESULTS We detected and confirmed gene-gene interactions between the HLA region and CTLA4, IRF5, and ITGAM and between PDCD1 and IL21 in patients with lupus. The most significant interaction detected by parametric analysis was between rs3131379 in the HLA region and rs231775 in CTLA4 (interaction odds ratio 1.19, Z = 3.95, P = 7.8 × 10(-5) [FDR ≤0.05], P for multifactor dimensionality reduction = 5.9 × 10(-45)). Importantly, our data suggest that in patients with lupus, the presence of the HLA lupus risk alleles in rs1270942 and rs3131379 increases the odds of also carrying the lupus risk allele in IRF5 (rs2070197) by 17% and 16%, respectively (P = 0.0028 and P = 0.0047, respectively). CONCLUSION We provide evidence for gene-gene epistasis in systemic lupus erythematosus. These findings support a role for genetic interaction contributing to the complexity of lupus heritability.
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Affiliation(s)
- Travis Hughes
- Arthritis & Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Adam Adler
- Arthritis & Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Jennifer A. Kelly
- Arthritis & Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Kenneth M. Kaufman
- Arthritis & Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
- Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- US Department of Veterans Affairs Medical Center, Oklahoma City, OK, USA
| | - Adrienne Williams
- Department of Biostatistical Sciences, Wake Forest University Health Sciences, Medical Center Blvd, Winston-Salem, NC, USA
| | - Carl D. Langefeld
- Department of Biostatistical Sciences, Wake Forest University Health Sciences, Medical Center Blvd, Winston-Salem, NC, USA
| | - Elizabeth E. Brown
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Graciela S. Alarcón
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Robert P. Kimberly
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jeffrey C. Edberg
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Rosalind Ramsey-Goldman
- Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Michelle Petri
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Susan A. Boackle
- Division of Rheumatology, School of Medicine, University of Colorado Denver, Aurora, CO, USA
| | - Anne M. Stevens
- Division of Rheumatology, Department of Pediatrics, University of Washington, and Center for Immunity and Immunotherapies, Seattle Children’s Research Institute, Seattle, WA, USA
| | - John D. Reveille
- Department of Medicine, University of Texas-Houston Health Science Center, Houston, TX, USA
| | - Elena Sanchez
- Arthritis & Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Javier Martin
- Instituto de Parasitología y Biomedicina López-Neyra, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Timothy B. Niewold
- Section of Rheumatology and Gwen Knapp Center for Lupus and Immunology Research, University of Chicago, Chicago, IL, USA
| | - Luis M. Vilá
- Department of Medicine, University of Puerto Rico Medical Sciences Campus, San Juan, Puerto Rico, USA
| | - R Hal Scofield
- Arthritis & Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
- Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- US Department of Veterans Affairs Medical Center, Oklahoma City, OK, USA
| | - Gary S. Gilkeson
- Department of Medicine, Division of Rheumatology, Medical University of South Carolina, Charleston, SC, USA
| | - Patrick M. Gaffney
- Arthritis & Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Lindsey A. Criswell
- Rosalind Russell Medical Research Center for Arthritis, University of California, San Francisco, San Francisco, CA, USA
| | - Kathy L. Moser
- Arthritis & Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Joan T. Merrill
- Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Clinical Pharmacology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Chaim O. Jacob
- Department of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Betty P. Tsao
- Division of Rheumatology, Department of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Judith A. James
- Arthritis & Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
- Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Timothy J. Vyse
- Divisions of Genetics and Molecular Medicine and Immunology, Infection and Inflammatory Disease, King’s College London, Guy’s Hospital, London, UK
| | - Marta E. Alarcón-Riquelme
- Arthritis & Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
- Center for Genomics and Oncological Research Pfizer-University of Granada-Junta de Andalucia, Granada, Spain
| | - John B. Harley
- Rheumatology Division and Autoimmune Genomics Center, Cincinnati Children’s Hospital Medical Center; and US Department of Veterans Affairs Medical Center, Cincinnati, OH, USA
| | - Bruce C. Richardson
- Division of Rheumatology, University of Michigan; and US Department of Veterans Affairs Medical Center, Ann Arbor, Michigan
| | - Amr H. Sawalha
- Arthritis & Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
- Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- US Department of Veterans Affairs Medical Center, Oklahoma City, OK, USA
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MacPherson M, Lek HS, Prescott A, Fagerholm SC. A systemic lupus erythematosus-associated R77H substitution in the CD11b chain of the Mac-1 integrin compromises leukocyte adhesion and phagocytosis. J Biol Chem 2011; 286:17303-10. [PMID: 21454473 PMCID: PMC3089572 DOI: 10.1074/jbc.m110.182998] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Mac-1 integrin is expressed mainly on myeloid cells and binds several ligands, including members of the ICAM family and the complement factor iC3b. It is involved in essential immunological processes, such as leukocyte extravasation and phagocytosis. In addition, Mac-1 has been described to negatively regulate immune cell signaling. Recently, a single nucleotide polymorphism conferring an amino acid change in the Mac-1 integrin extracellular domain, R77H, was shown to be associated with systemic lupus erythematosus. Here, we demonstrate that the R77H-substituted Mac-1 can be expressed on the cell surface in transfected cells and can undergo conformational changes in response to integrin activation. The affinity of the integrin for ICAMs is only partially reduced, but cell adhesion to ICAM-1 and ICAM-2 is severely compromised, and Jβ2.7 cells expressing R77H substituted integrins are deficient in adhesion to ICAM-1 under shear flow conditions. Importantly, cell adhesion to the complement factor iC3b is also diminished, and COS cells expressing R77H-substituted integrins display reduced iC3b-dependent phagocytosis. In addition, U937 cells expressing R77H-CD11b display increased IL-6 production as compared with WT-CD11b-expressing cells. These results suggest that the R77H substitution results in the deficiency of the mutated integrin to mediate cell adhesion to ligands such as ICAMs and iC3b. These deficiencies may ultimately lead to detrimental effects on the immune system and contribute to the development of systemic lupus erythematosus.
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Affiliation(s)
- Matthew MacPherson
- Division of Medical Sciences, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY, United Kingdom.
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18
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Warchoł T, Lianeri M, Łącki JK, Olesińska M, Jagodziński PP. ITGAM Arg77His is associated with disease susceptibility, arthritis, and renal symptoms in systemic lupus erythematosus patients from a sample of the Polish population. DNA Cell Biol 2010; 30:33-8. [PMID: 20666624 DOI: 10.1089/dna.2010.1041] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The ITGAM Arg77His (rs1143679) and Ala858Val (rs1143683) polymorphisms have been found to be strong contributors to systemic lupus erythematosus (SLE) development. There are evident population distinctions in terms of SLE distribution and manifestations; therefore, we investigated the distribution of the ITGAM Arg77His and Ala858Val polymorphisms in patients with SLE (n = 154) and control subjects (n = 276) in a sample of the Polish population. We observed that patients with the ITGAM His/His and Arg/His genotypes displayed a 1.811-fold increased risk of SLE incidence (95% confidence intervals [95% CI] = 1.171-2.802, p = 0.0089). Odds ratio (OR) for the homozygous ITGAM His/His genotype was 7.333 (95% CI = 0.8119-66.241, p = 0.0576). We also found that the ITGAM 858Val variant might be a risk factor in the occurrence of SLE; the OR for this allele amounted to 1.458 (95% CI = 1.021-2.080, p = 0.0372). There was an association of the ITGAM His/His and Arg/His genotypes with the occurrence of arthritis OR = 3.486 (95% CI = 1.619-7.508, p = 0.0015). We also observed an association between the ITGAM His/His and Arg/His genotypes and renal symptoms in the course of SLE OR = 2.975 (95% CI = 1.478-5.988; p = 0.0023). Our findings confirmed that there is an association of the ITGAM 77His or 858Val variants with SLE incidence and some clinical manifestation of this autoimmune disorder.
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Affiliation(s)
- Teresa Warchoł
- Department of Biochemistry and Molecular Biology, Poznan University of Medical Sciences, Poznan, Poland
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Cao C, Gao Y, Li Y, Antalis TM, Castellino FJ, Zhang L. The efficacy of activated protein C in murine endotoxemia is dependent on integrin CD11b. J Clin Invest 2010; 120:1971-80. [PMID: 20458145 PMCID: PMC2877939 DOI: 10.1172/jci40380] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2009] [Accepted: 03/17/2010] [Indexed: 12/16/2022] Open
Abstract
Activated protein C (APC), the only FDA-approved biotherapeutic drug for sepsis, possesses anticoagulant, antiinflammatory, and barrier-protective activities. However, the mechanisms underlying its anti-inflammatory functions are not well defined. Here, we report that the antiinflammatory activity of APC on macrophages is dependent on integrin CD11b/CD18, but not on endothelial protein C receptor (EPCR). We showed that CD11b/CD18 bound APC within specialized membrane microdomains/lipid rafts and facilitated APC cleavage and activation of protease-activated receptor-1 (PAR1), leading to enhanced production of sphingosine-1-phosphate (S1P) and suppression of the proinflammatory response of activated macrophages. Deletion of the gamma-carboxyglutamic acid domain of APC, a region critical for its anticoagulant activity and EPCR-dependent barrier protection, had no effect on its antiinflammatory function. Genetic inactivation of CD11b, PAR1, or sphingosine kinase-1, but not EPCR, abolished the ability of APC to suppress the macrophage inflammatory response in vitro. Using an LPS-induced mouse model of lethal endotoxemia, we showed that APC administration reduced the mortality of wild-type mice, but not CD11b-deficient mice. These data establish what we believe to be a novel mechanism underlying the antiinflammatory activity of APC in the setting of endotoxemia and provide clear evidence that the antiinflammatory function of APC is distinct from its barrier-protective function and anticoagulant activities.
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Affiliation(s)
- Chunzhang Cao
- Center for Vascular and Inflammatory Diseases, Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA.
W.M. Keck Center for Transgene Research, University of Notre Dame, Notre Dame, Indiana, USA
| | - Yamei Gao
- Center for Vascular and Inflammatory Diseases, Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA.
W.M. Keck Center for Transgene Research, University of Notre Dame, Notre Dame, Indiana, USA
| | - Yang Li
- Center for Vascular and Inflammatory Diseases, Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA.
W.M. Keck Center for Transgene Research, University of Notre Dame, Notre Dame, Indiana, USA
| | - Toni M. Antalis
- Center for Vascular and Inflammatory Diseases, Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA.
W.M. Keck Center for Transgene Research, University of Notre Dame, Notre Dame, Indiana, USA
| | - Francis J. Castellino
- Center for Vascular and Inflammatory Diseases, Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA.
W.M. Keck Center for Transgene Research, University of Notre Dame, Notre Dame, Indiana, USA
| | - Li Zhang
- Center for Vascular and Inflammatory Diseases, Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA.
W.M. Keck Center for Transgene Research, University of Notre Dame, Notre Dame, Indiana, USA
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Sándor N, Pap D, Prechl J, Erdei A, Bajtay Z. A novel, complement-mediated way to enhance the interplay between macrophages, dendritic cells and T lymphocytes. Mol Immunol 2009; 47:438-48. [PMID: 19796821 DOI: 10.1016/j.molimm.2009.08.025] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2009] [Revised: 08/13/2009] [Accepted: 08/28/2009] [Indexed: 01/23/2023]
Abstract
Recently it has been reported that human C3-deficiency is associated with impairments in dendritic cell differentiation. Here we investigated how complement C3 influences the phenotype and functional activity of human dendritic cells. We show that human monocyte-derived dendritic cells (MDCs) when incubated with native, hemolytically active C3, bind the activation fragments of C3 covalently. This reaction directs MDCs to increase expression of MHCII, CD83 and CD86, moreover it results in a significantly enhanced secretion of TNF-alpha, IL-6 and IL-8. A further functional consequence of C3b-fixation is the elevated capacity of the dendritic cells to stimulate allogeneic T cells. The distinct role of covalently fixed C3-fragments is strongly supported by our results obtained with MDCs where CD11b expression was downregulated by siRNA. To reveal the possible in vivo significance of the present findings we modelled a phenomenon occurring during inflammation, where C3 is produced locally by activated macrophages. In these cocultures MDCs were found to fix substantial amounts of macrophage derived C3-fragments on their cell membrane. Our data provide compelling evidence that antigen presenting cells arising in complement-sufficient environment mature to competent stimulators of T cells.
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Affiliation(s)
- Noémi Sándor
- Department of Immunology, Institute of Biology, Eötvös Loránd University, Pázmány Péter sétány 1/C, Budapest H-1117, Hungary
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Structure of the F-spondin domain of mindin, an integrin ligand and pattern recognition molecule. EMBO J 2009; 28:286-97. [PMID: 19153605 DOI: 10.1038/emboj.2008.288] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2008] [Accepted: 12/12/2008] [Indexed: 01/11/2023] Open
Abstract
Mindin (spondin-2) is an extracellular matrix protein of unknown structure that is required for efficient T-cell priming by dendritic cells. Additionally, mindin functions as a pattern recognition molecule for initiating innate immune responses. These dual functions are mediated by interactions with integrins and microbial pathogens, respectively. Mindin comprises an N-terminal F-spondin (FS) domain and C-terminal thrombospondin type 1 repeat (TSR). We determined the structure of the FS domain at 1.8-A resolution. The structure revealed an eight-stranded antiparallel beta-sandwich motif resembling that of membrane-targeting C2 domains, including a bound calcium ion. We demonstrated that the FS domain mediates integrin binding and identified the binding site by mutagenesis. The mindin FS domain therefore represents a new integrin ligand. We further showed that mindin recognizes lipopolysaccharide (LPS) through its TSR domain, and obtained evidence that C-mannosylation of the TSR influences LPS binding. Through these dual interactions, the FS and TSR domains of mindin promote activation of both adaptive and innate immune responses.
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Han S, Kim-Howard X, Deshmukh H, Kamatani Y, Viswanathan P, Guthridge JM, Thomas K, Kaufman KM, Ojwang J, Rojas-Villarraga A, Baca V, Orozco L, Rhodes B, Choi CB, Gregersen PK, Merrill JT, James JA, Gaffney PM, Moser KL, Jacob CO, Kimberly RP, Harley JB, Bae SC, Anaya JM, Alarcón-Riquelme ME, Matsuda K, Vyse TJ, Nath SK. Evaluation of imputation-based association in and around the integrin-alpha-M (ITGAM) gene and replication of robust association between a non-synonymous functional variant within ITGAM and systemic lupus erythematosus (SLE). Hum Mol Genet 2009; 18:1171-80. [PMID: 19129174 DOI: 10.1093/hmg/ddp007] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We recently identified a novel non-synonymous variant, rs1143679, at exon 3 of the ITGAM gene associated with systemic lupus erythematosus (SLE) susceptibility in European-Americans (EAs) and African-Americans. Using genome-wide association approach, three other studies also independently reported an association between SLE susceptibility and ITGAM or ITGAM-ITGAX region. The primary objectives of this study are to assess whether single or multiple causal variants from the same gene or any nearby gene(s) are involved in SLE susceptibility and to confirm a robust ITGAM association across nine independent data sets (n = 8211). First, we confirmed our previously reported association of rs1143679 (risk allele 'A') with SLE in EAs (P = 1.0 x 10(-8)) and Hispanic-Americans (P = 2.9 x 10(-5)). Secondly, using a comprehensive imputation-based association test, we found that ITGAM is one of the major non-human leukocyte antigen susceptibility genes for SLE, and the strongest association for EA is the same coding variant rs1143679 (log(10)Bayes factor=20, P = 6.17 x 10(-24)). Thirdly, we determined the robustness of rs1143679 association with SLE across three additional case-control samples, including UK (P = 6.2 x 10(-8)), Colombian (P = 3.6 x 10(-7)), Mexican (P = 0.002), as well as two independent sets of trios from UK (P(TDT) = 1.4 x 10(-5)) and Mexico (P(TDT) = 0.015). A meta-analysis combing all independent data sets greatly reinforces the association (P(meta) = 7.1 x 10(-50), odds ratio = 1.83, 95% confidence interval = 1.69-1.98, n = 10 046). However, this ITGAM association was not observed in the Korean or Japanese samples, in which rs1143679 is monomorphic for the non-risk allele (G). Taken together along with our earlier findings, these results demonstrate that the coding variant, rs1143679, best explains the ITGAM-SLE association, especially in European- and African-derived populations, but not in Asian populations.
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Affiliation(s)
- Shizhong Han
- Genetic Epidemiology Unit, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
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23
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A nonsynonymous functional variant in integrin-alpha(M) (encoded by ITGAM) is associated with systemic lupus erythematosus. Nat Genet 2008; 40:152-4. [PMID: 18204448 DOI: 10.1038/ng.71] [Citation(s) in RCA: 236] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2007] [Accepted: 11/30/2007] [Indexed: 11/08/2022]
Abstract
We identified and replicated an association between ITGAM (CD11b) at 16p11.2 and risk of systemic lupus erythematosus (SLE) in 3,818 individuals of European descent. The strongest association was at a nonsynonymous SNP, rs1143679 (P = 1.7 x 10(-17), odds ratio = 1.78). We further replicated this association in two independent samples of individuals of African descent (P = 0.0002 and 0.003; overall meta-analysis P = 6.9 x 10(-22)). The genetic association between ITGAM and SLE implicates the alpha(M)beta2-integrin adhesion pathway in disease development.
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Janssen BJC, Gros P. Conformational complexity of complement component C3. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2007; 586:291-312. [PMID: 16893080 DOI: 10.1007/0-387-34134-x_20] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Bert J C Janssen
- Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Dept. of Chemistry, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
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25
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Nochi H, Shinomiya T, Tamoto K. Characterization of hyaluronan-binding proteins on guinea pig polymorphonuclear leukocytes: possible involvement of complement receptor type 3 (CR3, CD11b/CD18) in the hyaluronan-leukocyte interaction. J Biochem 2007; 139:59-70. [PMID: 16428320 DOI: 10.1093/jb/mvj002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Hyaluronan (HA), a high-molecular-weight glycosaminoglycan ubiquitously present in the extracellular matrices (ECMs) of animals, plays important roles in ECM organization and cell behavior through binding to hyaluronan-binding proteins (HABPs). We previously reported that HA has anti-inflammatory effects on guinea pig phagocytes, although the nature of guinea pig HABPs was unknown. In this study, we characterized guinea pig HABPs on peritoneal polymorphonuclear leukocytes (PMNs) and blood neutrophils by flow cytometry and affinity chromatography. It was found that PMNs express diverse HABPs with different molecular weights. These HABPs maximally bound with HA over a wide pH range (6-8), and recognized HAs as small as the pentadisaccharide units of d-glucuronic acid and N-acetyl-d-glucosamine. Furthermore, they could be divided into Mg(2+)-dependent and Ca(2+)/Mg(2+)-independent groups. Interestingly, two proteins in the Mg(2+)-dependent group were found to be the two subunits of complement receptor type 3 (CR3, CD11b/CD18). Unlike PMNs, blood neutrophils expressed several functionally inactive HABPs. Among these inactive HABPs, Mg(2+)-dependent proteins including CR3 but not Ca(2+)/Mg(2+)-independent proteins were activated on phorbol ester-stimulation. These results show the existence of diverse HABPs on guinea pig neutrophils and the cell activation-dependent activation of HABPs. It is also suggested that the CR3-HA interaction is possibly involved in the regulation of neutrophil function.
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Affiliation(s)
- Hiromi Nochi
- Department of Immunology and Microbiology, Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Ishikari-Tobetsu 061-0293
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26
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Eisenhardt SU, Schwarz M, Schallner N, Soosairajah J, Bassler N, Huang D, Bode C, Peter K. Generation of activation-specific human anti-alphaMbeta2 single-chain antibodies as potential diagnostic tools and therapeutic agents. Blood 2006; 109:3521-8. [PMID: 17164347 DOI: 10.1182/blood-2006-03-007179] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The leukocyte integrin Mac-1 (alpha(M)beta(2)) plays a pivotal role in inflammation and host defense. Upon leukocyte activation, Mac-1 undergoes a conformational change exposing interaction sites for multiple ligands. We aimed to generate single-chain antibodies (scFv's) directed against activation-specific Mac-1 ligand-binding sites. Using human scFv phage libraries, we developed subtractive strategies with depletion of phages binding to nonactivated Mac-1 and selection of phages binding to activated Mac-1, using monocytes as well as CHO cells transfected with native or mutated, activated Mac-1. Three scFv clones demonstrated exclusive binding to activated Mac-1. Mac-1 binding of the ligands fibrinogen, heparin, and ICAM-1, but not C3bi, was inhibited. Using alanine substitutions, the paratope was identified within the heavy chain HCDR3s of the scFv's. The epitope was localized to Lys(245)-Arg(261) of the alpha(M) I-domain. In a pilot study with septicemic patients, we provide initial support for the use of these scFv's as markers of monocyte activation and as potential diagnostic tools. Potential therapeutic use was tested in adhesion assays under static and flow conditions demonstrating the selective blockade of activated monocytes only. Furthermore, scFv HCDR3-derived peptides retain selectivity for the activated integrin, providing a unique template for the potential development of inhibitors that are specific for the activated Mac-1.
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27
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Janssen BJC, Gros P. Structural insights into the central complement component C3. Mol Immunol 2006; 44:3-10. [PMID: 16875735 DOI: 10.1016/j.molimm.2006.06.017] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2006] [Accepted: 06/22/2006] [Indexed: 11/30/2022]
Abstract
C3 is a central protein of the complement system, which is important to immune defense and provides a link between innate and adaptive immunity. Three pathways of complement activation converge at the activation of C3 yielding a diverse set of biological responses. This versatile and flexible molecule interacts with various proteins to fulfill its functions. Here we review recent insights gained from the crystal structure determinations of human, native C3 and its physiological down-regulation product C3c. The data provided, for the first time, a complete and detailed view of the composition and arrangement of the domains in C3. Comparison of C3 with C3c indicates marked flexibility of the molecule, particularly in the alpha-chain. We discuss the observed domain rearrangements, conformational changes and the location of various protein binding sites. These detailed, and structural, insights are important for developing models of the molecular mechanisms underlying the diverse biological activities of this large and complex molecule.
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Affiliation(s)
- Bert J C Janssen
- Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Department of Chemistry, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
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28
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Cao C, Lawrence DA, Li Y, Von Arnim CAF, Herz J, Su EJ, Makarova A, Hyman BT, Strickland DK, Zhang L. Endocytic receptor LRP together with tPA and PAI-1 coordinates Mac-1-dependent macrophage migration. EMBO J 2006; 25:1860-70. [PMID: 16601674 PMCID: PMC1456942 DOI: 10.1038/sj.emboj.7601082] [Citation(s) in RCA: 146] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2005] [Accepted: 03/15/2006] [Indexed: 11/09/2022] Open
Abstract
Migration of activated macrophages is essential for resolution of acute inflammation and the initiation of adaptive immunity. Here, we show that efficient macrophage migration in inflammatory environment depends on Mac-1 recognition of a binary complex consisting of fibrin within the provisional matrix and the protease tPA (tissue-type plasminogen activator). Subsequent neutralization of tPA by its inhibitor PAI-1 enhances binding of the integrin-protease-inhibitor complex to the endocytic receptor LRP (lipoprotein receptor-related protein), triggering a switch from cell adhesion to cell detachment. Genetic inactivation of Mac-1, tPA, PAI-1 or LRP but not the protease uPA abrogates macrophage migration. The defective macrophage migration in PAI-1-deficient mice can be restored by wild-type but not by a mutant PAI-1 that does not interact with LRP. In vitro analysis shows that tPA promotes Mac-1-mediated adhesion, whereas PAI-1 and LRP facilitate its transition to cell retraction. Our results emphasize the importance of ordered transitions both temporally and spatially between individual steps of cell migration, and support a model where efficient migration of inflammatory macrophages depends on cooperation of three physiologically prominent systems (integrins, coagulation and fibrinolysis, and endocytosis).
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Affiliation(s)
- Chunzhang Cao
- Department of Physiology and Surgery, Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Daniel A Lawrence
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Yang Li
- Department of Physiology and Surgery, Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine, Baltimore, MD, USA
| | | | - Joachim Herz
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Enming J Su
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Alexandra Makarova
- Alzheimer's Disease Research Laboratory, Harvard Medical School, Charlestown, MA, USA
| | - Bradley T Hyman
- Alzheimer's Disease Research Laboratory, Harvard Medical School, Charlestown, MA, USA
| | - Dudley K Strickland
- Department of Physiology and Surgery, Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Li Zhang
- Department of Physiology and Surgery, Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine, Baltimore, MD, USA
- Departments of Physiology and Surgery, Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine, 800 W. Baltimore Street, Baltimore, MD 21201, USA. Tel.: +1 410 706 8040; Fax: +1 410 706 8121; E-mail:
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29
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Silva CA, Zuliani JP, Assakura MT, Mentele R, Camargo ACM, Teixeira CFP, Serrano SMT. Activation of αMβ2-mediated phagocytosis by HF3, a P-III class metalloproteinase isolated from the venom of Bothrops jararaca. Biochem Biophys Res Commun 2004; 322:950-6. [PMID: 15336556 DOI: 10.1016/j.bbrc.2004.08.012] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2004] [Indexed: 11/24/2022]
Abstract
The integrin alpha(M)beta(2) regulates important cell functions in inflammation being the primary phagocytic receptor on macrophages. HF3, a metalloproteinase isolated from Bothrops jararaca venom, is a potent hemorrhagic toxin. A cDNA encoding HF3 indicated that it is a multidomain molecule composed of a pro-domain, a catalytic domain with a zinc binding sequence, followed by disintegrin-like and cysteine-rich domains. It is known that metalloproteinases play a relevant role in the pathogenesis of venom-induced local tissue damage including inflammation. In this study we evaluated the effects of native HF3 and its recombinant disintegrin-like/cysteine-rich domains (DC-HF3) on alpha(M)beta(2)-mediated phagocytosis of opsonized-zymosan particles by macrophages. HF3 and DC-HF3 significantly increased phagocytosis and this activity was inhibited by anti-alpha(M) and anti-beta(2) antibodies. The data show the ability of P-III metalloproteinases to activate macrophages for phagocytosis through integrin alpha(M)beta(2) and suggest that the disintegrin-like/cysteine-rich domains are important for this effect. This is the first report on the activation of phagocytosis via alpha(M)beta(2) integrin by a metalloproteinase containing disintegrin-like/cysteine-rich domains.
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Affiliation(s)
- Carlos A Silva
- Laboratorio Especial de Toxinologia Aplicada-CAT/CEPID, Instituto Butantan, CEP 05503-900, Sao Paulo, Brazil
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