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Roche V, Sandoval V, Wolford C, Senders Z, Kim JA, Ribeiro SP, Huang AY, Sekaly RP, Lyons J, Zhang M. Carbohydrate ligand engagement with CD11b enhances differentiation of tumor-associated myeloid cells for immunotherapy of solid cancers. J Immunother Cancer 2023; 11:e006205. [PMID: 37399354 DOI: 10.1136/jitc-2022-006205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/11/2023] [Indexed: 07/05/2023] Open
Abstract
BACKGROUND Efforts to modulate the function of tumor-associated myeloid cell are underway to overcome the challenges in immunotherapy and find a cure. One potential therapeutic target is integrin CD11b, which can be used to modulate the myeloid-derived cells and induce tumor-reactive T-cell responses. However, CD11b can bind to multiple different ligands, leading to various myeloid cell functions such as adhesion, migration, phagocytosis, and proliferation. This has created a major challenge in understanding how CD11b converts the differences in the receptor-ligand binding into subsequent signaling responses and using this information for therapeutic development. METHODS This study aimed to investigate the antitumor effect of a carbohydrate ligand, named BG34-200, which modulates the CD11b+ cells. We have applied peptide microarrays, multiparameter FACS (fluorescence-activated cell analysis) analysis, cellular/molecular immunological technology, advanced microscopic imaging, and transgenic mouse models of solid cancers, to study the interaction between BG34-200 carbohydrate ligand and CD11b protein and the resulting immunological changes in the context of solid cancers, including osteosarcoma, advanced melanoma, and pancreatic ductal adenocarcinoma (PDAC). RESULTS Our results show that BG34-200 can bind directly to the activated CD11b on its I (or A) domain, at previously unreported peptide residues, in a multisite and multivalent manner. This engagement significantly impacts the biological function of tumor-associated inflammatory monocytes (TAIMs) in osteosarcoma, advanced melanoma, and PDAC backgrounds. Importantly, we observed that the BG34-200-CD11b engagement triggered endocytosis of the binding complexes in TAIMs, which induced intracellular F-actin cytoskeletal rearrangement, effective phagocytosis, and intrinsic ICAM-1 (intercellular adhesion molecule I) clustering. These structural biological changes resulted in the differentiation in TAIMs into monocyte-derived dendritic cells, which play a crucial role in T-cell activation in the tumor microenvironment. CONCLUSIONS Our research has advanced the current understanding of the molecular basis of CD11b activation in solid cancers, revealing how it converts the differences in BG34 carbohydrate ligands into immune signaling responses. These findings could pave the way for the development of safe and novel BG34-200-based therapies that modulate myeloid-derived cell functions, thereby enhancing immunotherapy for solid cancers.
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Affiliation(s)
- Veronique Roche
- Department of Biomedical Engineering, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio, USA
| | - Victor Sandoval
- Department of Biomedical Engineering, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Department of Surgical Oncology, University Hospitals Cleveland Medical Center, Cleveland, Ohio, USA
| | - Claire Wolford
- Department of Biomedical Engineering, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio, USA
| | - Zachary Senders
- Department of Biomedical Engineering, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Department of Surgical Oncology, University Hospitals Cleveland Medical Center, Cleveland, Ohio, USA
| | - Julian Anthony Kim
- Department of Surgical Oncology, University Hospitals Cleveland Medical Center, Cleveland, Ohio, USA
| | - Susan Pereira Ribeiro
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Alex Yicheng Huang
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Department of Pediatrics, UH Rainbow Babies & Children's Hospital, Cleveland, Ohio, USA
| | - Rafick-Pierre Sekaly
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Joshua Lyons
- Department of Biomedical Engineering, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Department of Surgical Oncology, University Hospitals Cleveland Medical Center, Cleveland, Ohio, USA
| | - Mei Zhang
- Department of Biomedical Engineering, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio, USA
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2
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Tomasek K, Leithner A, Glatzova I, Lukesch MS, Guet CC, Sixt M. Type 1 piliated uropathogenic Escherichia coli hijack the host immune response by binding to CD14. eLife 2022; 11:78995. [PMID: 35881547 PMCID: PMC9359703 DOI: 10.7554/elife.78995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Accepted: 07/19/2022] [Indexed: 11/13/2022] Open
Abstract
A key attribute of persistent or recurring bacterial infections is the ability of the pathogen to evade the host’s immune response. Many Enterobacteriaceae express type 1 pili, a pre-adapted virulence trait, to invade host epithelial cells and establish persistent infections. However, the molecular mechanisms and strategies by which bacteria actively circumvent the immune response of the host remain poorly understood. Here, we identified CD14, the major co-receptor for lipopolysaccharide detection, on mouse dendritic cells (DCs) as a binding partner of FimH, the protein located at the tip of the type 1 pilus of Escherichia coli. The FimH amino acids involved in CD14 binding are highly conserved across pathogenic and non-pathogenic strains. Binding of the pathogenic strain CFT073 to CD14 reduced DC migration by overactivation of integrins and blunted expression of co-stimulatory molecules by overactivating the NFAT (nuclear factor of activated T-cells) pathway, both rate-limiting factors of T cell activation. This response was binary at the single-cell level, but averaged in larger populations exposed to both piliated and non-piliated pathogens, presumably via the exchange of immunomodulatory cytokines. While defining an active molecular mechanism of immune evasion by pathogens, the interaction between FimH and CD14 represents a potential target to interfere with persistent and recurrent infections, such as urinary tract infections or Crohn’s disease.
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Affiliation(s)
- Kathrin Tomasek
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | | | - Ivana Glatzova
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | | | - Calin C Guet
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Michael Sixt
- Institute of Science and Technology Austria, Klosterneuburg, Austria
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3
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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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4
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Cai C, Sun H, Hu L, Fan Z. Visualization of integrin molecules by fluorescence imaging and techniques. ACTA ACUST UNITED AC 2021; 45:229-257. [PMID: 34219865 PMCID: PMC8249084 DOI: 10.32604/biocell.2021.014338] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Integrin molecules are transmembrane αβ heterodimers involved in cell adhesion, trafficking, and signaling. Upon activation, integrins undergo dynamic conformational changes that regulate their affinity to ligands. The physiological functions and activation mechanisms of integrins have been heavily discussed in previous studies and reviews, but the fluorescence imaging techniques -which are powerful tools for biological studies- have not. Here we review the fluorescence labeling methods, imaging techniques, as well as Förster resonance energy transfer assays used to study integrin expression, localization, activation, and functions.
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Affiliation(s)
- Chen Cai
- Department of Immunology, School of Medicine, UConn Health, Farmington, 06030, USA
| | - Hao Sun
- Department of Medicine, University of California, San Diego, La Jolla, 92093, USA
| | - Liang Hu
- Cardiovascular Institute of Zhengzhou University, Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450051, China
| | - Zhichao Fan
- Department of Immunology, School of Medicine, UConn Health, Farmington, 06030, USA
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5
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Feng W, Nguyen H, Shen D, Deng H, Jiang Z, Podolnikova N, Ugarova T, Wang X. Structural Characterization of the Interaction between the α MI-Domain of the Integrin Mac-1 (α Mβ 2) and the Cytokine Pleiotrophin. Biochemistry 2021; 60:182-193. [PMID: 33427449 DOI: 10.1021/acs.biochem.0c00700] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Integrin Mac-1 (αMβ2) is an adhesion receptor vital to many functions of myeloid leukocytes. It is also the most promiscuous member of the integrin family capable of recognizing a broad range of ligands. In particular, its ligand-binding αMI-domain is known to bind cationic proteins/peptides depleted in acidic residues. This contradicts the canonical ligand-binding mechanism of αI-domains, which requires an acidic amino acid in the ligand to coordinate the divalent cation within the metal ion-dependent adhesion site (MIDAS) of αI-domains. The lack of acidic amino acids in the αMI-domain-binding sequences suggests the existence of an as-yet uncharacterized interaction mechanism. In the present study, we analyzed interactions of the αMI-domain with a representative Mac-1 ligand, the cationic cytokine pleiotrophin (PTN). Through NMR chemical shift perturbation analysis, cross saturation, NOESY, and mutagenesis studies, we found the interaction between the αMI-domain and PTN is divalent cation-independent and mediated mostly by hydrophobic contacts between the N-terminal domain of PTN and residues in the α5-β5 loop of αMI-domain. The observation that increased ionic strength weakens the interaction between the proteins indicates electrostatic forces may also play a significant role in the binding. On the basis of the results from these experiments, we formulated a model of the interaction between the αMI-domain and PTN.
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6
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Autotransporter-Mediated Display of Complement Receptor Ligands by Gram-Negative Bacteria Increases Antibody Responses and Limits Disease Severity. Pathogens 2020; 9:pathogens9050375. [PMID: 32422907 PMCID: PMC7281241 DOI: 10.3390/pathogens9050375] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 05/06/2020] [Accepted: 05/11/2020] [Indexed: 12/13/2022] Open
Abstract
The targeting of immunogens/vaccines to specific immune cells is a promising approach for amplifying immune responses in the absence of exogenous adjuvants. However, the targeting approaches reported thus far require novel, labor-intensive reagents for each vaccine and have primarily been shown as proof-of-concept with isolated proteins and/or inactivated bacteria. We have engineered a plasmid-based, complement receptor-targeting platform that is readily applicable to live forms of multiple gram-negative bacteria, including, but not limited to, Escherichia coli, Klebsiella pneumoniae, and Francisella tularensis. Using F. tularensis as a model, we find that targeted bacteria show increased binding and uptake by macrophages, which coincides with increased p38 and p65 phosphorylation. Mice vaccinated with targeted bacteria produce higher titers of specific antibody that recognizes a greater diversity of bacterial antigens. Following challenge with homologous or heterologous isolates, these mice exhibited less weight loss and/or accelerated weight recovery as compared to counterparts vaccinated with non-targeted immunogens. Collectively, these findings provide proof-of-concept for plasmid-based, complement receptor-targeting of live gram-negative bacteria.
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7
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Deville SS, Cordes N. The Extracellular, Cellular, and Nuclear Stiffness, a Trinity in the Cancer Resistome-A Review. Front Oncol 2019; 9:1376. [PMID: 31867279 PMCID: PMC6908495 DOI: 10.3389/fonc.2019.01376] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 11/22/2019] [Indexed: 12/19/2022] Open
Abstract
Alterations in mechano-physiological properties of a tissue instigate cancer burdens in parallel to common genetic and epigenetic alterations. The chronological and mechanistic interrelation between the various extra- and intracellular aspects remains largely elusive. Mechano-physiologically, integrins and other cell adhesion molecules present the main mediators for transferring and distributing forces between cells and the extracellular matrix (ECM). These cues are channeled via focal adhesion proteins, termed the focal adhesomes, to cytoskeleton and nucleus and vice versa thereby affecting the pathophysiology of multicellular cancer tissues. In combination with simultaneous activation of diverse downstream signaling pathways, the phenotypes of cancer cells are created and driven characterized by deregulated transcriptional and biochemical cues that elicit the hallmarks of cancer. It, however, remains unclear how elastostatic modifications, i.e., stiffness, in the extracellular, intracellular, and nuclear compartment contribute and control the resistance of cancer cells to therapy. In this review, we discuss how stiffness of unique tumor components dictates therapy response and what is known about the underlying molecular mechanisms.
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Affiliation(s)
- Sara Sofia Deville
- OncoRay – National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Helmholtz-Zentrum Dresden - Rossendorf, Technische Universität Dresden, Dresden, Germany
- Department of Radiation Oncology, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
- Helmholtz-Zentrum Dresden - Rossendorf, Institute of Radiooncology - OncoRay, Dresden, Germany
| | - Nils Cordes
- OncoRay – National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Helmholtz-Zentrum Dresden - Rossendorf, Technische Universität Dresden, Dresden, Germany
- Department of Radiation Oncology, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
- Helmholtz-Zentrum Dresden - Rossendorf, Institute of Radiooncology - OncoRay, Dresden, Germany
- German Cancer Consortium (DKTK), Dresden, Germany
- Germany German Cancer Research Center (DKFZ), Heidelberg, Germany
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8
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Hemodialysis-related changes in phenotypical features of monocytes. Sci Rep 2018; 8:13964. [PMID: 30228352 PMCID: PMC6143543 DOI: 10.1038/s41598-018-31889-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 08/12/2018] [Indexed: 12/26/2022] Open
Abstract
Hemodialysis (HD) patients exhibit chronic inflammation and leukocyte activation. We investigated the surface-marker profile of monocytes by flow cytometry to assess the chronic effect of uremia and the acute effect of dialysis on their phenotypical and functional features in 16 healthy controls (CON) and 15 HD patients before and after a polysulfone-based dialysis session. Median fluorescence intensities were analyzed indicating expression of CD14, CD16, integrins (CD11b, CD18), chemokine receptors (CCR2, CX3CR1), scavenger receptors (CD36, CD163) and Toll-like receptor-2 (TLR2). Before and after dialysis, HD patients harbour 0.9-fold less CD14++CD16- (Mo1), 1.8-fold more CD14++CD16+ (Mo2) and CD14+CD16++ (Mo3) monocytes than CON. HD patients' Mo1 showed elevated expression of CD11b (1.7-fold), CD18 (1.2-fold) and CD36 (2.1-fold), whereas CD163 expression was reduced in Mo1 and Mo2 (0.6-fold) compared to CON. These markers remained unaffected by dialysis. CX3CR1 expression on Mo2 and Mo3 was lower in HD patients before (0.8-fold) and further diminished after dialysis (0.6-fold). Stimulation of monocytes resulted in diminished responses in HD patients compared to CON. In conclusion, a systematic analysis of the expression of particular surface markers on distinct monocyte subsets may help to distinguish between uremia and/or dialysis induced effects and to evaluate the functionality of monocytes and biocompatibility of HD.
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9
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Koutsogiannaki S, Zha H, Yuki K. Volatile Anesthetic Isoflurane Attenuates Liver Injury in Experimental Polymicrobial Sepsis Model. ACTA ACUST UNITED AC 2018; 5:63-74. [PMID: 29977977 PMCID: PMC6029873 DOI: 10.31480/2330-4871/071] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Volatile anesthetics are often administered to patients with sepsis for
procedural anesthesia or sedation in intensive care units. Sepsis still carries
significant morbidities and mortalities, and organ injuries pose major
complications. Early liver dysfunction is associated with poor outcome mainly as
a result of overwhelming neutrophil recruitment. Leukocyte function-associated
antigen-1 (LFA-1) and macrophage-1 antigen (Mac-1) are major adhesion molecules
on neutrophils and involved in neutrophil recruitment. We have previously showed
that volatile anesthetic isoflurane inhibited LFA-1 and Mac-1. Here we studied
the role of isoflurane, LFA-1 and Mac-1 on neutrophil recruitment to the liver
and liver injury using experimental polymicrobial abdominal sepsis induced by
cecal ligation and puncture (CLP) surgery. We used wild type (WT), LFA-1, Mac-1
and intercellular adhesion molecule-1 (ICAM-1) knockout (KO) mice. Following the
induction of sepsis by CLP surgery, a group of mice were exposed to isoflurane
for 2 hours. We found that Mac-1 and ICAM-1, but not LFA-1 were involved in
neutrophil recruitment to liver. Isoflurane attenuated neutrophil recruitment
and liver injury in WT and LFA-1 KO mice. Mac-1 KO mice had limited neutrophil
recruitment and liver injury, both of which were not attenuated by isoflurane
further, suggesting that isoflurane mitigated liver injury via Mac-1. Mac-1
colocalized with ICAM-1 and fibrinogen on liver tissues. In the presence of
fibrinogen Mac-1 bound ICAM-1 significantly more, while LFA-1 bound less to
ICAM-1, suggesting that Mac-1 used fibrinogen as a bridging molecule to bind
ICAM-1. In conclusion, isoflurane exposure attenuated neutrophil recruitment and
liver injury via Mac-1.
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Affiliation(s)
- Sophia Koutsogiannaki
- Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, Boston, MA, USA.,Department of Anaesthesia, Harvard Medical School, Boston, MA, USA
| | - Hui Zha
- Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, Boston, MA, USA.,Department of Anaesthesia, Harvard Medical School, Boston, MA, USA.,Department of Pediatric, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Koichi Yuki
- Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, Boston, MA, USA.,Department of Anaesthesia, Harvard Medical School, Boston, MA, USA
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10
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Vimalathas P, Farris A, Letner D, Deshpande V, Yajnik V, Shreffler W, Garber J. Integrin αM activation and upregulation on esophageal eosinophils and periostin-mediated eosinophil survival in eosinophilic esophagitis. Immunol Cell Biol 2018; 96:426-438. [PMID: 29424023 DOI: 10.1111/imcb.12018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 02/01/2018] [Accepted: 02/02/2018] [Indexed: 12/12/2022]
Abstract
Eosinophilic esophagitis (EoE) is an increasingly recognized allergic disease associated with dysphagia and esophageal fibrosis. We aimed to determine expression patterns of specific eosinophil integrins that promote eosinophilic infiltration of the esophageal epithelium, and to determine how key EoE-related cytokines influence eosinophil activation and survival. Esophageal and peripheral eosinophils were isolated from 20 adult subjects with EoE for immunophenotyping and integrin profiling using multicolor flow cytometry and immunohistochemistry. Expression signatures of eosinophil integrins were further assessed by immunohistochemistry using serial sections of esophageal biopsy specimens. Purified eosinophils were used to assess the effect of EoE-relevant cytokines and recombinant periostin on expression of known eosinophil integrins and eosinophil survival and activation. We found that resting eosinophils express high levels of the β2-pairing integrins αL and αM, and lower levels of α4, α6 and α4β7. The migration of peripheral eosinophils to the esophagus is characterized by the specific induction of αM, and a significant increase in the proportion of αM in high-activity conformation. Periostin, a secreted extracellular matrix protein that is significantly overexpressed in EoE, enhances eosinophil survival, and this effect is mediated by αM interaction. Integrin αM is a specific marker of activated tissue eosinophils in EoE, and promotes eosinophil survival through interactions with periostin. The ability of αMβ2 to mediate eosinophil tissue residency via periostin represents a key mechanism for disease development and a potential therapeutic target in EoE.
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Affiliation(s)
| | - Alexandra Farris
- Gastrointestinal Unit, Massachusetts General Hospital, Boston, MA, USA
| | - Dorothea Letner
- Gastrointestinal Unit, Massachusetts General Hospital, Boston, MA, USA
| | - Vikram Deshpande
- Department of Pathology, Massachusetts General Hospital, Boston, MA, USA.,Department of Pathology, Harvard Medical School, Boston, MA, USA
| | - Vijay Yajnik
- Gastrointestinal Unit, Massachusetts General Hospital, Boston, MA, USA.,Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Wayne Shreffler
- Food Allergy Center, Division of Allergy & Immunology, Massachusetts General Hospital, Boston, MA, USA.,Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - John Garber
- Gastrointestinal Unit, Massachusetts General Hospital, Boston, MA, USA.,Department of Medicine, Harvard Medical School, Boston, MA, USA
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11
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Dissecting intrinsic and ligand-induced structural communication in the β3 headpiece of integrins. Biochim Biophys Acta Gen Subj 2017; 1861:2367-2381. [DOI: 10.1016/j.bbagen.2017.05.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 05/20/2017] [Accepted: 05/22/2017] [Indexed: 12/15/2022]
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12
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Wald T, Osickova A, Masin J, Liskova PM, Petry-Podgorska I, Matousek T, Sebo P, Osicka R. Transmembrane segments of complement receptor 3 do not participate in cytotoxic activities but determine receptor structure required for action of Bordetella adenylate cyclase toxin. Pathog Dis 2016; 74:ftw008. [PMID: 26802078 DOI: 10.1093/femspd/ftw008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/17/2016] [Indexed: 11/13/2022] Open
Abstract
Adenylate cyclase toxin-hemolysin (CyaA, ACT or AC-Hly) of the whooping cough agent Bordetella pertussis penetrates phagocytes expressing the integrin complement receptor 3 (CR3, CD11b/CD18, α(M)β(2) or Mac-1). CyaA translocates its adenylate cyclase (AC) enzyme domain into cell cytosol and catalyzes unregulated conversion of ATP to cAMP, thereby subverting cellular signaling. In parallel, CyaA forms small cation-selective membrane pores that permeabilize cells for potassium efflux, contributing to cytotoxicity of CyaA and eventually provoking colloid-osmotic cell lysis. To investigate whether the single-pass α-helical transmembrane segments of CR3 subunits CD11b and CD18 do directly participate in AC domain translocation and/or pore formation by the toxin, we expressed in CHO cells variants of CR3 that contained artificial transmembrane segments, or lacked the transmembrane segment(s) at all. The results demonstrate that the transmembrane segments of CR3 are not directly involved in the cytotoxic activities of CyaA but serve for maintaining CR3 in a conformation that is required for efficient toxin binding and action.
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Affiliation(s)
- Tomas Wald
- Institute of Microbiology of the CAS, v. v. i., Videnska 1083, 142 20, Prague 4, Czech Republic
| | - Adriana Osickova
- Institute of Microbiology of the CAS, v. v. i., Videnska 1083, 142 20, Prague 4, Czech Republic Department of Biochemistry, Faculty of Science, Charles University in Prague, Hlavova 8, 128 43, Prague 2, Czech Republic
| | - Jiri Masin
- Institute of Microbiology of the CAS, v. v. i., Videnska 1083, 142 20, Prague 4, Czech Republic
| | - Petra M Liskova
- Institute of Microbiology of the CAS, v. v. i., Videnska 1083, 142 20, Prague 4, Czech Republic Department of Genetics and Microbiology, Faculty of Science, Charles University in Prague, Vinicna 5, 128 44 Prague 2, Czech Republic
| | - Inga Petry-Podgorska
- Institute of Analytical Chemistry of the CAS, v. v. i., Veveri 97, 602 00 Brno, Czech Republic
| | - Tomas Matousek
- Institute of Analytical Chemistry of the CAS, v. v. i., Veveri 97, 602 00 Brno, Czech Republic
| | - Peter Sebo
- Institute of Microbiology of the CAS, v. v. i., Videnska 1083, 142 20, Prague 4, Czech Republic
| | - Radim Osicka
- Institute of Microbiology of the CAS, v. v. i., Videnska 1083, 142 20, Prague 4, Czech Republic
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13
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Fürnrohr BG, Stein M, Rhodes B, Chana PS, Schett G, Vyse TJ, Herrmann M, Mielenz D. Reduced Fluorescence versus Forward Scatter Time-of-Flight and Increased Peak versus Integral Fluorescence Ratios Indicate Receptor Clustering in Flow Cytometry. THE JOURNAL OF IMMUNOLOGY 2015; 195:377-85. [PMID: 26026066 DOI: 10.4049/jimmunol.1401889] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 04/20/2015] [Indexed: 11/19/2022]
Abstract
Clustering of surface receptors is often required to initiate signal transduction, receptor internalization, and cellular activation. To study the kinetics of clustering, we developed an economic high-throughput method using flow cytometry. The quantification of receptor clustering by flow cytometry is based on the following two observations: first, the fluorescence signal length (FL time-of-flight [ToF]) decreases relative to the forward scatter signal length (FSc-ToF), and second, the peak FL (FL-peak) increases relative to the integral FL (FL-integral) upon clustering of FL-labeled surface receptors. Receptor macroclustering can therefore be quantified using the ratios FL-ToF/FSc-ToF (method ToF) or FL-peak/FL-integral (method Peak). We have used these methods to analyze clustering of two immune receptors known to undergo different conformational and oligomeric states: the BCR and the complement receptor 3 (CR3), on murine splenocytes, purified B cells, and human neutrophils. Engagement of both the BCR and CR3, on immortalized as well as primary murine B cells and human neutrophil, respectively, resulted in decreased FL-ToF/FSc-ToF and increased FL-peak/FL-integral ratios. Manipulation of the actin-myosin cytoskeleton altered BCR clustering which could be measured using the established parameters. To confirm clustering of CR3 on neutrophils, we applied imaging flow cytometry. Because receptor engagement is as a biological process dependent on cell viability, energy metabolism, and temperature, receptor clustering can only be quantified by gating on viable cells under physiological conditions. In summary, with this novel method, receptor clustering on nonadherent cells can easily be monitored by high-throughput conventional flow cytometry.
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Affiliation(s)
- Barbara G Fürnrohr
- Division of Molecular Immunology, Department of Internal Medicine 3, University of Erlangen-Nuremberg, Nikolaus Fiebiger Centre, 91054 Erlangen, Germany; Division of Genetics and Molecular Medicine, King's College London, Guy's Hospital, London SE1 9RT, United Kingdom; Division of Immunology, Infection and Inflammatory Disease, King's College London, Guy's Hospital, London SE1 9RT, United Kingdom; Division of Genetic Epidemiology, Medical University Innsbruck, 6020 Innsbruck, Austria
| | - Merle Stein
- Division of Molecular Immunology, Department of Internal Medicine 3, University of Erlangen-Nuremberg, Nikolaus Fiebiger Centre, 91054 Erlangen, Germany
| | - Benjamin Rhodes
- Division of Genetics and Molecular Medicine, King's College London, Guy's Hospital, London SE1 9RT, United Kingdom; Division of Immunology, Infection and Inflammatory Disease, King's College London, Guy's Hospital, London SE1 9RT, United Kingdom; Department of Rheumatology, University Hospitals Birmingham National Health Service Foundation Trust, Edgbaston, Birmingham B15 2TH, United Kingdom
| | - Prabhjoat S Chana
- Flow Cytometry Core Facility, National Institute for Health Research, Guy's and St. Thomas' National Health Service Foundation Trust/King's College London Comprehensive Biomedical Research Centre, Guy's Hospital, London SE1 9RT, United Kingdom
| | - Georg Schett
- Department of Internal Medicine 3, University of Erlangen-Nuremberg, 91054 Erlangen, Germany; and Institute for Clinical Immunology, Department of Internal Medicine 3, University of Erlangen-Nuremberg, 91054 Erlangen, Germany
| | - Timothy J Vyse
- Division of Genetics and Molecular Medicine, King's College London, Guy's Hospital, London SE1 9RT, United Kingdom; Division of Immunology, Infection and Inflammatory Disease, King's College London, Guy's Hospital, London SE1 9RT, United Kingdom
| | - Martin Herrmann
- Department of Internal Medicine 3, University of Erlangen-Nuremberg, 91054 Erlangen, Germany; and Institute for Clinical Immunology, Department of Internal Medicine 3, University of Erlangen-Nuremberg, 91054 Erlangen, Germany
| | - Dirk Mielenz
- Division of Molecular Immunology, Department of Internal Medicine 3, University of Erlangen-Nuremberg, Nikolaus Fiebiger Centre, 91054 Erlangen, Germany;
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14
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Jung S, Yuki K. Differential effects of volatile anesthetics on leukocyte integrin macrophage-1 antigen. J Immunotoxicol 2015; 13:148-56. [PMID: 25746395 DOI: 10.3109/1547691x.2015.1019596] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Macrophage-1 antigen (Mac-1, αMβ2) is a leukocyte adhesion molecule that plays a significant role in leukocyte crawling and phagocytosis, and is homologous to its sister protein leukocyte function-associated antigen-1 (LFA-1, αLβ2). The authors have previously demonstrated that volatile anesthetics isoflurane and sevoflurane bound to and inhibited LFA-1. Here, the hypothesis tested was that isoflurane and sevoflurane would inhibit Mac-1. A binding assay of Mac-1 to its ligand inter-cellular adhesion molecule-1 (ICAM-1) using V-bottom plates was established. The effect of isoflurane and sevoflurane on Mac-1 was examined using this ICAM-1 binding assay and by probing exposure of activation-sensitive epitopes. The docking program Glide was used to predict anesthetic binding site(s) on Mac-1. The functional role of this predicted binding site was then assessed by introducing point mutations in this region. Lastly, the effect of anesthetic on activating mutants was evaluated. The results indicated that isoflurane inhibited binding of Mac-1 to ICAM-1, but sevoflurane did not. Isoflurane also attenuated the exposure of the activation-sensitive epitopes. The docking simulation predicted the isoflurane binding site to be at the cavity underneath the α7 helix of the ligand binding domain (the αM I domain). Point mutants at this predicted binding site contained both activating and deactivating mutants, suggesting its functional significance. The binding of activating mutants αM-Y267A β2-WT and αM-L312A β2-WT to ICAM-1 was not affected by isoflurane, but binding of another activating mutant αM-WT β2-L132A was inhibited supporting the binding of isoflurane to this cavity. The conclusion reached from these findings was that isoflurane inhibited Mac-1 binding to ICAM-1 by binding to the cavity underneath the α7 helix of the αM I domain, but sevoflurane did not. Thus, because these common clinical volatile anesthetics demonstrated different effects on Mac-1, this implied their effects on the immune system might differ.
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Affiliation(s)
- Sungeun Jung
- a Department of Anesthesiology , Perioperative and Pain Medicine, Boston Children's Hospital , Boston , MA , USA and.,b Department of Anaesthesia , Harvard Medical School , Boston , MA , USA
| | - Koichi Yuki
- a Department of Anesthesiology , Perioperative and Pain Medicine, Boston Children's Hospital , Boston , MA , USA and.,b Department of Anaesthesia , Harvard Medical School , Boston , MA , USA
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15
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Podolnikova NP, Podolnikov AV, Haas TA, Lishko VK, Ugarova TP. Ligand recognition specificity of leukocyte integrin αMβ2 (Mac-1, CD11b/CD18) and its functional consequences. Biochemistry 2015; 54:1408-20. [PMID: 25613106 DOI: 10.1021/bi5013782] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The broad recognition specificity exhibited by integrin α(M)β2 (Mac-1, CD11b/CD18) has allowed this adhesion receptor to play innumerable roles in leukocyte biology, yet we know little about how and why α(M)β2 binds its multiple ligands. Within α(M)β2, the α(M)I-domain is responsible for integrin's multiligand binding properties. To identify its recognition motif, we screened peptide libraries spanning sequences of many known protein ligands for α(M)I-domain binding and also selected the α(M)I-domain recognition sequences by phage display. Analyses of >1400 binding and nonbinding peptides derived from peptide libraries showed that a key feature of the α(M)I-domain recognition motif is a small core consisting of basic amino acids flanked by hydrophobic residues. Furthermore, the peptides selected by phage display conformed to a similar pattern. Identification of the recognition motif allowed the construction of an algorithm that reliably predicts the α(M)I-domain binding sites in the α(M)β2 ligands. The recognition specificity of the α(M)I-domain resembles that of some chaperones, which allows it to bind segments exposed in unfolded proteins. The disclosure of the α(M)β2 binding preferences allowed the prediction that cationic host defense peptides, which are strikingly enriched in the α(M)I-domain recognition motifs, represent a new class of α(M)β2 ligands. This prediction has been tested by examining the interaction of α(M)β2 with the human cathelicidin peptide LL-37. LL-37 induced a potent α(M)β2-dependent cell migratory response and caused activation of α(M)β2 on neutrophils. The newly revealed recognition specificity of α(M)β2 toward unfolded protein segments and cationic proteins and peptides suggests that α(M)β2 may serve as a previously proposed "alarmin" receptor with important roles in innate host defense.
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Affiliation(s)
- Nataly P Podolnikova
- Center for Metabolic and Vascular Biology, School of Life Sciences, Arizona State University , Tempe, Arizona 85287, United States
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16
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Abstract
Asthma is characterized by airway inflammation rich in eosinophils. Airway eosinophilia is associated with exacerbations and has been suggested to play a role in airway remodelling. Recruitment of eosinophils from the circulation requires that blood eosinophils become activated, leading to their arrest on the endothelium and extravasation. Circulating eosinophils can be envisioned as potentially being in different activation states, including non-activated, pre-activated or 'primed', or fully activated. In addition, the circulation can potentially be deficient of pre-activated or activated eosinophils, because such cells have marginated on activated endothelium or extravasated into the tissue. A number of eosinophil surface proteins, including CD69, L-selectin, intercellular adhesion molecule-1 (ICAM-1, CD54), CD44, P-selectin glycoprotein ligand-1 (PSGL-1, CD162), cytokine receptors, Fc receptors, integrins including αM integrin (CD11b), and activated conformations of Fc receptors and integrins, have been proposed to report cell activation. Variation in eosinophil activation states may be associated with asthma activity. Eosinophil surface proteins proposed to be activation markers, with a particular focus on integrins, and evidence for associations between activation states of blood eosinophils and features of asthma are reviewed here. Partial activation of β1 and β2 integrins on blood eosinophils, reported by monoclonal antibodies (mAbs) N29 and KIM-127, is associated with impaired pulmonary function and airway eosinophilia, respectively, in non-severe asthma. The association with lung function does not occur in severe asthma, presumably due to greater eosinophil extravasation, specifically of activated or pre-activated cells, in severe disease.
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Affiliation(s)
- M W Johansson
- Department of Biomolecular Chemistry, University of Wisconsin, Madison, WI, USA
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18
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Affiliation(s)
- M. W. Johansson
- Department of Biomolecular Chemistry; University of Wisconsin; Madison WI USA
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Maiti AK, Kim-Howard X, Motghare P, Pradhan V, Chua KH, Sun C, Arango-Guerrero MT, Ghosh K, Niewold TB, Harley JB, Anaya JM, Looger LL, Nath SK. Combined protein- and nucleic acid-level effects of rs1143679 (R77H), a lupus-predisposing variant within ITGAM. Hum Mol Genet 2014; 23:4161-76. [PMID: 24608226 DOI: 10.1093/hmg/ddu106] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Integrin alpha M (ITGAM; CD11b) is a component of the macrophage-1 antigen complex, which mediates leukocyte adhesion, migration and phagocytosis as part of the immune system. We previously identified a missense polymorphism, rs1143679 (R77H), strongly associated with systemic lupus erythematosus (SLE). However, the molecular mechanisms of this variant are incompletely understood. A meta-analysis of published and novel data on 28 439 individuals with European, African, Hispanic and Asian ancestries reinforces genetic association between rs1143679 and SLE [Pmeta = 3.60 × 10(-90), odds ratio (OR) = 1.76]. Since rs1143679 is in the most active region of chromatin regulation and transcription factor binding in ITGAM, we quantitated ITGAM RNA and surface protein levels in monocytes from patients with each rs1143679 genotype. We observed that transcript levels significantly decreased for the risk allele ('A') relative to the non-risk allele ('G'), in a dose-dependent fashion: ('AA' < 'AG' < 'GG'). CD11b protein levels in patients' monocytes were directly correlated with RNA levels. Strikingly, heterozygous individuals express much lower (average 10- to 15-fold reduction) amounts of the 'A' transcript than 'G' transcript. We found that the non-risk sequence surrounding rs1143679 exhibits transcriptional enhancer activity in vivo and binds to Ku70/80, NFKB1 and EBF1 in vitro, functions that are significantly reduced with the risk allele. Mutant CD11b protein shows significantly reduced binding to fibrinogen and vitronectin, relative to non-risk, both in purified protein and in cellular models. This two-pronged contribution (nucleic acid- and protein-level) of the rs1143679 risk allele to decreasing ITGAM activity provides insight into the molecular mechanisms of its potent association with SLE.
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Affiliation(s)
- Amit K Maiti
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Xana Kim-Howard
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Prasenjeet Motghare
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | | | - Kek Heng Chua
- Department of Biomedical Science, University of Malaya, Kuala Lumpur, Malaysia
| | - Celi Sun
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - María Teresa Arango-Guerrero
- Center for Autoimmune Diseases Research (CREA), School of Medicine and Health Sciences, Universidad del Rosario, Bogotá, Colombia
| | | | - Timothy B Niewold
- Division of Rheumatology and Department of Immunology, Mayo Clinic, Rochester, MN, USA
| | - John B Harley
- Cincinnati Children's Hospital Medical Center and the US Department of Veterans Affairs Medical Center, Cincinnati, OH, USA
| | - Juan-Manual Anaya
- Center for Autoimmune Diseases Research (CREA), School of Medicine and Health Sciences, Universidad del Rosario, Bogotá, Colombia
| | - Loren L Looger
- Howard Hughes Medical Institute, Janelia Farm Research Campus, Ashburn, VA, USA
| | - Swapan K Nath
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
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20
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Zhou Y, Wu J, Kucik DF, White NB, Redden DT, Szalai AJ, Bullard DC, Edberg JC. Multiple lupus-associated ITGAM variants alter Mac-1 functions on neutrophils. ACTA ACUST UNITED AC 2014; 65:2907-16. [PMID: 23918739 DOI: 10.1002/art.38117] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 07/30/2013] [Indexed: 01/29/2023]
Abstract
OBJECTIVE Multiple studies have demonstrated that single-nucleotide polymorphisms (SNPs) in the ITGAM locus (including the nonsynonymous SNPs rs1143679, rs1143678, and rs1143683) are associated with systemic lupus erythematosus (SLE). ITGAM encodes the protein CD11b, a subunit of the β2 integrin Mac-1. The purpose of this study was to determine the effects of ITGAM genetic variation on the biologic functions of neutrophil Mac-1. METHODS Neutrophils from ITGAM-genotyped and -sequenced healthy donors were isolated for functional studies. The phagocytic capacity of neutrophil ITGAM variants was probed with complement-coated erythrocytes, serum-treated zymosan, heat-treated zymosan, and IgG-coated erythrocytes. The adhesion capacity of ITGAM variants, in adhering to either purified intercellular adhesion molecule 1 or tumor necrosis factor α-stimulated endothelial cells, was assessed in a flow chamber. Expression levels of total CD11b and activation of CD11b were assessed by flow cytometry. RESULTS Mac-1-mediated neutrophil phagocytosis, determined in cultures with 2 different complement-coated particles, was significantly reduced in individuals with nonsynonymous variant alleles of ITGAM. This reduction in phagocytosis was related to variation at either rs1143679 (in the β-propeller region) or rs1143678/rs1143683 (highly linked SNPs in the cytoplasmic/calf-1 regions). Phagocytosis mediated by Fcγ receptors was also significantly reduced in donors with variant ITGAM alleles. Similarly, firm adhesion of neutrophils was significantly reduced in individuals with variant ITGAM alleles. These functional alterations were not attributable to differences in total receptor expression or activation. CONCLUSION The nonsynonymous ITGAM variants rs1143679 and rs1143678/rs113683 contribute to altered Mac-1 function on neutrophils. These results underscore the need to consider multiple nonsynonymous SNPs when assessing the functional consequences of ITGAM variation on immune cell processes and the risk of SLE.
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21
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Ueno N, Harker KS, Clarke EV, McWhorter FY, Liu WF, Tenner AJ, Lodoen MB. Real-time imaging of Toxoplasma-infected human monocytes under fluidic shear stress reveals rapid translocation of intracellular parasites across endothelial barriers. Cell Microbiol 2013; 16:580-95. [PMID: 24245749 DOI: 10.1111/cmi.12239] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2013] [Revised: 10/15/2013] [Accepted: 11/11/2013] [Indexed: 12/24/2022]
Abstract
Peripheral blood monocytes are actively infected by Toxoplasma gondii and can function as 'Trojan horses' for parasite spread in the bloodstream. Using dynamic live-cell imaging, we visualized the transendothelial migration (TEM) of T. gondii-infected primary human monocytes during the initial minutes following contact with human endothelium. On average, infected and uninfected monocytes required only 9.8 and 4.1 min, respectively, to complete TEM. Infection increased monocyte crawling distances and velocities on endothelium, but overall TEM frequencies were comparable between infected and uninfected cells. In the vasculature, monocytes adhere to endothelium under the conditions of shear stress found in rapidly flowing blood. Remarkably, the addition of fluidic shear stress increased the TEM frequency of infected monocytes 4.5-fold compared to static conditions (to 45.2% from 10.3%). Infection led to a modest increase in expression of the high-affinityconformation of the monocyte integrin Mac-1 (CD11b/CD18), and Mac-1 accumulated near endothelial junctions during TEM. Blocking Mac-1 inhibited the crawling and TEM of infected monocytes to a greater degree than uninfected monocytes, and blocking the Mac-1 ligand, ICAM-1, dramatically reduced crawling and TEM for both populations. These findings contribute to a greater understanding of parasite dissemination from the vasculature into tissues.
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Affiliation(s)
- Norikiyo Ueno
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, USA; Institute for Immunology, University of California, Irvine, CA, USA
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22
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Subramani J, Ghosh M, Rahman MM, Caromile LA, Gerber C, Rezaul K, Han DK, Shapiro LH. Tyrosine phosphorylation of CD13 regulates inflammatory cell-cell adhesion and monocyte trafficking. THE JOURNAL OF IMMUNOLOGY 2013; 191:3905-12. [PMID: 23997214 DOI: 10.4049/jimmunol.1301348] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
CD13 is a large cell surface peptidase expressed on the monocytes and activated endothelial cells that is important for homing to and resolving the damaged tissue at sites of injury. We showed previously that cross-linking of human monocytic CD13 with activating Abs induces strong adhesion to endothelial cells in a tyrosine kinase- and microtubule-dependent manner. In the current study, we examined the molecular mechanisms underlying these observations in vitro and in vivo. We found that cross-linking of CD13 on U937 monocytic cells induced phosphorylation of a number of proteins, including Src, FAK, and ERK, and inhibition of these abrogated CD13-dependent adhesion. We found that CD13 itself was phosphorylated in a Src-dependent manner, which was an unexpected finding because its 7-aa cytoplasmic tail was assumed to be inert. Furthermore, CD13 was constitutively associated with the scaffolding protein IQGAP1, and CD13 cross-linking induced complex formation with the actin-binding protein α-actinin, linking membrane-bound CD13 to the cytoskeleton, further supporting CD13 as an inflammatory adhesion molecule. Mechanistically, mutation of the conserved CD13 cytoplasmic tyrosine to phenylalanine abrogated adhesion; Src, FAK, and ERK phosphorylation; and cytoskeletal alterations upon Ab cross-linking. Finally, CD13 was phosphorylated in isolated murine inflammatory peritoneal exudate cells, and adoptive transfer of monocytic cell lines engineered to express the mutant CD13 were severely impaired in their ability to migrate into the inflamed peritoneum, confirming that CD13 phosphorylation is relevant to inflammatory cell trafficking in vivo. Therefore, this study identifies CD13 as a novel, direct activator of intracellular signaling pathways in pathophysiological conditions.
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Affiliation(s)
- Jaganathan Subramani
- Center for Vascular Biology, University of Connecticut Health Center, Farmington, CT 06030
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23
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Johansson MW, Gunderson KA, Kelly EAB, Denlinger LC, Jarjour NN, Mosher DF. Anti-IL-5 attenuates activation and surface density of β(2) -integrins on circulating eosinophils after segmental antigen challenge. Clin Exp Allergy 2013; 43:292-303. [PMID: 23414537 DOI: 10.1111/j.1365-2222.2012.04065.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Revised: 06/14/2012] [Accepted: 06/25/2012] [Indexed: 12/12/2022]
Abstract
BACKGROUND IL-5 activates α(M) β(2) integrin on blood eosinophils in vitro. Eosinophils in bronchoalveolar lavage (BAL) following segmental antigen challenge have activated β(2) -integrins. OBJECTIVE To identify roles for IL-5 in regulating human eosinophil integrins in vivo. METHODS Blood and BAL eosinophils were analysed by flow cytometry in ten subjects with allergic asthma who underwent a segmental antigen challenge protocol before and after anti-IL-5 administration. RESULTS Blood eosinophil reactivity with monoclonal antibody (mAb) KIM-127, which recognizes partially activated β(2) -integrins, was decreased after anti-IL-5. Before anti-IL-5, surface densities of blood eosinophil β(2) , α(M) and α(L) integrin subunits increased modestly post challenge. After anti-IL-5, such increases did not occur. Before or after anti-IL-5, surface densities of β(2) , α(M) , α(L) and α(D) and reactivity with KIM-127 and mAb CBRM1/5, which recognizes high-activity α(M) β(2) , were similarly high on BAL eosinophils 48 h post-challenge. Density and activation state of β(1) -integrins on blood and BAL eosinophils were not impacted by anti-IL-5, even though anti-IL-5 ablated a modest post-challenge increase on blood or BAL eosinophils of P-selectin glycoprotein ligand-1 (PSGL-1), a receptor for P-selectin that causes activation of β(1) -integrins. Forward scatter of blood eosinophils post-challenge was less heterogeneous and on the average decreased after anti-IL-5; however, anti-IL-5 had no effect on the decreased forward scatter of eosinophils in post-challenge BAL compared with eosinophils in blood. Blood eosinophil KIM-127 reactivity at the time of challenge correlated with the percentage of eosinophils in BAL post-challenge. CONCLUSION AND CLINICAL RELEVANCE IL-5 supports a heterogeneous population of circulating eosinophils with partially activated β(2) -integrins and is responsible for up-regulation of β(2) -integrins and PSGL-1 on circulating eosinophils following segmental antigen challenge but has minimal effects on properties of eosinophils in BAL. Dampening of β(2) -integrin function of eosinophils in transit to inflamed airway may contribute to the decrease in lung inflammation caused by anti-IL-5.
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Affiliation(s)
- M W Johansson
- Department of Biomolecular Chemistry, University of Wisconsin, Madison, WI, USA.
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24
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Ovcharenko A, Granot G, Shpilberg O, Raanani P. Retinoic acid induces adhesion and migration in NB4 cells through Pyk2 signaling. Leuk Res 2013; 37:956-62. [PMID: 23587524 DOI: 10.1016/j.leukres.2013.03.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Revised: 02/03/2013] [Accepted: 03/17/2013] [Indexed: 12/21/2022]
Abstract
Since the introduction of all-trans-retinoic acid (ATRA) treatment for acute promyelocytic leukemia (APL) there has been increasing concern about extramedullary disease (EMD) progression despite favorable response in the bone marrow. We postulated that ATRA treatment enhances migration and adhesion abilities possibly enabling APL cells to inhabit extramedullary sites. We revealed an increase in adhesion, migration and invasion capabilities of NB4 cells following ATRA treatment. ATRA induced upregulation of Pyk2 mRNA, protein and phosphorylation levels and enhanced Pyk2 interaction with paxillin and vinculin. Pyk2 inhibition resulted in a reduction of NB4 cell adhesion and migration following ATRA treatment. These results indicate that in vitro Pyk2 might function to regulate cell adhesion and motility following ATRA treatment and its upregulated expression may contribute to EMD development in APL patients.
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Affiliation(s)
- Adelina Ovcharenko
- Felsenstein Medical Research Center, Tel Aviv University, Petah Tikva, Israel
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25
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Johansson MW, Mosher DF. Integrin activation States and eosinophil recruitment in asthma. Front Pharmacol 2013; 4:33. [PMID: 23554594 PMCID: PMC3612688 DOI: 10.3389/fphar.2013.00033] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Accepted: 03/11/2013] [Indexed: 12/21/2022] Open
Abstract
Eosinophil arrest and recruitment to the airway in asthma are mediated, at least in part, by integrins. Eosinophils express α4β1, α6β1, αLβ2, αMβ2, αXβ2, αDβ2, and α4β7 integrins, which interact with counter-receptors on other cells or ligands in the extracellular matrix. Whether a given integrin-ligand pair mediates cell adhesion and migration depends on the activation state of the integrin. Integrins exist in an inactive bent, an intermediate-activity extended closed, and a high-activity extended open conformation. Integrin activation states can be monitored by conformation-specific monoclonal antibodies (mAbs). Studies in mice indicate that both β1 and β2 integrins mediate eosinophil recruitment to the lung. In vitro studies indicate that α4β1 and αMβ2 are the principal integrins mediating eosinophil adhesion, including to vascular cell adhesion molecule-1 and the novel αMβ2 ligand periostin. In vivo, blood eosinophils have intermediate-activity β1 integrins, as judged by mAb N29, apparently resulting from eosinophil binding of P-selectin on the surface of activated platelets, and have a proportion of their β2 integrins in the intermediate conformation, as judged by mAb KIM-127, apparently due to exposure to low concentrations of interleukin-5 (IL-5). Airway eosinophils recovered by bronchoalveolar lavage (BAL) after segmental antigen challenge have high-activity β1 integrins and high-activity αMβ2 that does not require IL-5. Here we review information on how the activation states of eosinophil β1 and β2 integrins correlate with measurements of eosinophil recruitment and pulmonary function in asthma. Blood eosinophil N29 reactivity is associated with decreased lung function under various circumstances in non-severe asthma and KIM-127 with BAL eosinophil numbers, indicating that intermediate-activity α4β1 and αMβ2 of blood eosinophils are important for eosinophil arrest and consequently for recruitment and aspects of asthma.
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Affiliation(s)
- Mats W Johansson
- Department of Biomolecular Chemistry, University of Wisconsin Madison, WI, USA
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Levin L, Zelzion E, Nachliel E, Gutman M, Tsfadia Y, Einav Y. A single disulfide bond disruption in the β3 integrin subunit promotes thiol/disulfide exchange, a molecular dynamics study. PLoS One 2013; 8:e59175. [PMID: 23527123 PMCID: PMC3601072 DOI: 10.1371/journal.pone.0059175] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Accepted: 02/12/2013] [Indexed: 11/30/2022] Open
Abstract
The integrins are a family of membrane receptors that attach a cell to its surrounding and play a crucial function in cell signaling. The combination of internal and external stimuli alters a folded non-active state of these proteins to an extended active configuration. The β3 subunit of the platelet αIIbβ3 integrin is made of well-structured domains rich in disulfide bonds. During the activation process some of the disulfides are re-shuffled by a mechanism requiring partial reduction of some of these bonds; any disruption in this mechanism can lead to inherent blood clotting diseases. In the present study we employed Molecular Dynamics simulations for tracing the sequence of structural fluctuations initiated by a single cysteine mutation in the β3 subunit of the receptor. These simulations showed that in-silico protein mutants exhibit major conformational deformations leading to possible disulfide exchange reactions. We suggest that any mutation that prevents Cys560 from reacting with one of the Cys567–Cys581 bonded pair, thus disrupting its ability to participate in a disulfide exchange reaction, will damage the activation mechanism of the integrin. This suggestion is in full agreement with previously published experiments. Furthermore, we suggest that rearrangement of disulfide bonds could be a part of a natural cascade of thiol/disulfide exchange reactions in the αIIbβ3 integrin, which are essential for the native activation process.
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Affiliation(s)
- Lihie Levin
- Biochemistry and Molecular Biology Department, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Ehud Zelzion
- Biochemistry and Molecular Biology Department, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
- Mathematical Biology Unit, Faculty of Sciences, Holon Institute of Technology, Holon, Israel
| | - Esther Nachliel
- Biochemistry and Molecular Biology Department, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Menachem Gutman
- Biochemistry and Molecular Biology Department, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Yossi Tsfadia
- Biochemistry and Molecular Biology Department, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
- * E-mail: (YT); (YE)
| | - Yulia Einav
- Mathematical Biology Unit, Faculty of Sciences, Holon Institute of Technology, Holon, Israel
- * E-mail: (YT); (YE)
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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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28
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Mor-Cohen R, Rosenberg N, Einav Y, Zelzion E, Landau M, Mansour W, Averbukh Y, Seligsohn U. Unique disulfide bonds in epidermal growth factor (EGF) domains of β3 affect structure and function of αIIbβ3 and αvβ3 integrins in different manner. J Biol Chem 2012; 287:8879-91. [PMID: 22308022 DOI: 10.1074/jbc.m111.311043] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The β3 subunit of αIIbβ3 and αvβ3 integrins contains four epidermal growth factor (EGF)-like domains. Each domain harbors four disulfide bonds of which one is unique for integrins. We previously discerned a regulatory role of the EGF-4 Cys-560-Cys-583 unique bond for αIIbβ3 activation. In this study we further investigated the role of all four integrin unique bonds in both αIIbβ3 and αvβ3. We created β3 mutants harboring serine substitutions of each or both cysteines that disrupt the four unique bonds (Cys-437-Cys-457 in EGF-1, Cys-473-Cys-503 in EGF-2, Cys-523-Cys-544 in EGF-3, and Cys-560-Cys-583 in EGF-4) and transfected them into baby hamster kidney cells together with normal αv or αIIb. Flow cytometry was used to measure surface expression of αIIbβ3 and αvβ3 and their activity state by soluble fibrinogen binding. Most cysteine substitutions caused similarly reduced surface expression of both receptors. Disrupting all four unique disulfide bonds by single cysteine substitutions resulted in variable constitutive activation of αIIbβ3 and αvβ3. In contrast, whereas double C437S/C457S and C473S/C503S mutations yielded constitutively active αIIbβ3 and αvβ3, the C560S/C583S mutation did not, and the C523S/C544S mutation only yielded constitutively active αIIbβ3. Activation of C523S/C544S αvβ3 mutant by activating antibody and dithiothreitol was also impaired. Molecular dynamics of C523S/C544S β3 in αIIbβ3 but not in αvβ3 displayed an altered stable conformation. Our findings indicate that unique disulfide bonds in β3 differently affect the function of αIIbβ3 and αvβ3 and suggest a free sulfhydryl-dependent regulatory role for Cys-560-Cys-583 in both αIIbβ3 and αvβ3 and for Cys-523-Cys-544 only in αvβ3.
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Affiliation(s)
- Ronit Mor-Cohen
- the Amalia Biron Research Institute of Thrombosis and Hemostasis, Chaim Sheba Medical Center, Tel-Hashomer, Israel.
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29
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Das M, Ithychanda SS, Qin J, Plow EF. Migfilin and filamin as regulators of integrin activation in endothelial cells and neutrophils. PLoS One 2011; 6:e26355. [PMID: 22043318 PMCID: PMC3197140 DOI: 10.1371/journal.pone.0026355] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Accepted: 09/25/2011] [Indexed: 12/18/2022] Open
Abstract
Cell adhesion and migration depend on engagement of extracellular matrix ligands by integrins. Integrin activation is dynamically regulated by interactions of various cytoplasmic proteins, such as filamin and integrin activators, talin and kindlin, with the cytoplasmic tail of the integrin β subunit. Although filamin has been suggested to be an inhibitor of integrin activation, direct functional evidence for the inhibitory role of filamin is limited. Migfilin, a filamin-binding protein enriched at cell-cell and cell-extracellular matrix contact sites, can displace filamin from β1 and β3 integrins and promote integrin activation. However, its role in activation and functions of different β integrins in human vascular cells is unknown. In this study, using flow cytometry, we demonstrate that filamin inhibits β1 and αIIbβ3 integrin activation, and migfilin can overcome its inhibitory effect. Migfilin protein is widely expressed in different adherent and circulating blood cells and can regulate integrin activation in naturally-occurring vascular cells, endothelial cells and neutrophils. Migfilin can activate β1, β2 and β3 integrins and promote integrin mediated responses while migfilin depletion impairs the spreading and migration of endothelial cells. Thus, filamin can act broadly as an inhibitor and migfilin is a promoter of integrin activation.
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Affiliation(s)
- Mitali Das
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Sujay Subbayya Ithychanda
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Jun Qin
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Edward F. Plow
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
- * E-mail:
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30
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Cleavage of the CD11b extracellular domain by the leukocyte serprocidins is critical for neutrophil detachment during chemotaxis. Blood 2011; 117:4885-94. [PMID: 21403131 DOI: 10.1182/blood-2010-05-287722] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The β(2)-integrin CD11b/CD18 mediates the firm adhesion of neutrophils (PMNs) to epithelial monolayers, a key step in PMN transepithelial migration. To complete the transmigration process, adherent PMNs must detach from epithelial monolayer surfaces to move forward. The mechanism that governs the detachment of adherent PMNs, however, is not clear. Here, we present evidence that cleavage of the CD11b extracellular domain containing the ligand-binding I-domain by 3 structural and functional related serine proteases (elastase, proteinase-3 and cathepsin G) serves as a novel mechanism for PMN detachment after the initial cell adhesion. Kinetic studies showed that the cleavage of CD11b is positively correlated with PMN detachment and subsequent transmigration. Moreover, the results demonstrated that elastase, proteinase-3 and cathepsin G all cleaved the purified, functionally active form of CD11b in a pattern similar to the CD11b shedding that occurs during PMN transmigration. Their cleavage sites on purified CD11b were located at (761)Thr-Ala(762) (elastase/proteinase-3) and (760)Phe-Thr(761) (cathepsin G), respectively. CD11b cleavage and PMN detachment and chemotaxis, were impaired in elastase/cathepsin G-deficient Beige mice; this defect could be restored by the addition of extracellular elastase. By illustrating CD11b shedding by elastase, proteinase-3 and cathepsin G as a novel mechanism for PMN detachment, our study provides novel therapeutic targets for controlling inflammation.
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31
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Rogers TH, Babensee JE. The role of integrins in the recognition and response of dendritic cells to biomaterials. Biomaterials 2010; 32:1270-9. [PMID: 21030075 DOI: 10.1016/j.biomaterials.2010.10.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2010] [Accepted: 10/06/2010] [Indexed: 01/28/2023]
Abstract
Biomaterials have the potential to be utilized as immunostimulatory or immunosuppressive delivery agents for biologics. It is hypothesized that this is directed by the ability of a biomaterial to drive dendritic cells (DC) in situ toward an immunostimulatory or an immunosuppressive phenotype, respectively. However, the specific pattern recognition receptors (PRRs) that DCs use to recognize and respond to biomaterials are unknown. From among the many receptors that DCs use to recognize and respond to foreign entities, herein the focus is on integrins. A biomaterial that induces DC maturation, namely poly(lactic-co-glycolic) acid (PLGA), supported increased human monocyte-derived DC adhesion and up-regulation of integrin receptor gene expression, measured via RT-PCR, as compared to culture on tissue culture polystyrene (TCPS). This was not observed for a biomaterial that does not support DC maturation. Through antibody-blocking techniques, the adhesion to both TCPS and PLGA was found to be β(2) integrin dependent and β(1) independent. Significantly, inhibiting β(2)-mediated adhesion to biomaterials via blocking antibodies also lowered the level of maturation of DCs (CD86 expression). β(2) integrins (but not β(1)) were found localized in biomaterial-adherent DC podosomes and also were found in direct contact with the PLGA surface. Therefore, it appeared that β(2) integrin-mediated adhesion is involved in determining the state of DC maturation on the PLGA surface. DC adhesion to biomaterials may be engaged or avoided to manipulate an immune response to biological component delivered with a biomaterial carrier.
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Affiliation(s)
- Todd H Rogers
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, USA
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32
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Role of complement and Fc{gamma} receptors in the protective activity of the long pentraxin PTX3 against Aspergillus fumigatus. Blood 2010; 116:5170-80. [PMID: 20829368 DOI: 10.1182/blood-2009-12-258376] [Citation(s) in RCA: 154] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pentraxin 3 (PTX3) is a soluble pattern recognition molecule playing a nonredundant role in resistance against Aspergillus fumigatus. The present study was designed to investigate the molecular pathways involved in the opsonic activity of PTX3. The PTX3 N-terminal domain was responsible for conidia recognition, but the full-length molecule was necessary for opsonic activity. The PTX3-dependent pathway of enhanced neutrophil phagocytic activity involved complement activation via the alternative pathway; Fcγ receptor (FcγR) IIA/CD32 recognition of PTX3-sensitized conidia and complement receptor 3 (CR3) activation; and CR3 and CD32 localization to the phagocytic cup. Gene targeted mice (ptx3, FcR common γ chain, C3, C1q) validated the in vivo relevance of the pathway. In particular, the protective activity of exogenous PTX3 against A fumigatus was abolished in FcR common γ chain-deficient mice. Thus, the opsonic and antifungal activity of PTX3 is at the crossroad between complement, complement receptor 3-, and FcγR-mediated recognition. Because short pentraxins (eg, C-reactive protein) interact with complement and FcγR, the present results may have general significance for the mode of action of these components of the humoral arm of innate immunity.
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33
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Zhang H, Liu JH, Yang W, Springer T, Shimaoka M, Wang JH. Structural basis of activation-dependent binding of ligand-mimetic antibody AL-57 to integrin LFA-1. Proc Natl Acad Sci U S A 2009; 106:18345-50. [PMID: 19805116 PMCID: PMC2775275 DOI: 10.1073/pnas.0909301106] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2009] [Indexed: 01/07/2023] Open
Abstract
The activity of integrin LFA-1 (alpha(L)beta(2)) to its ligand ICAM-1 is regulated through the conformational changes of its ligand-binding domain, the I domain of alpha(L) chain, from an inactive, low-affinity closed form (LA), to an intermediate-affinity form (IA), and then finally, to a high-affinity open form (HA). A ligand-mimetic human monoclonal antibody AL-57 (activated LFA-1 clone 57) was identified by phage display to specifically recognize the affinity-upregulated I domain. Here, we describe the crystal structures of the Fab fragment of AL-57 in complex with IA, as well as in its unligated form. We discuss the structural features conferring AL-57's strong selectivity for the high affinity, open conformation of the I domain. The AL-57-binding site overlaps the ICAM-1 binding site on the I domain. Furthermore, an antibody Asp mimics an ICAM Glu by forming a coordination to the metal-ion dependent adhesion site (MIDAS). The structure also reveals better shape complementarity and a more hydrophobic interacting interface in AL-57 binding than in ICAM-1 binding. The results explain AL-57's antagonistic mimicry of LFA-1's natural ligands, the ICAM molecules.
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Affiliation(s)
- Hongmin Zhang
- Department of Pediatrics, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA
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34
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Abstract
Receptor-mediated phagocytosis is a complex process that mediates the internalization, by a cell, of other cells and large particles; this is an important physiological event not only in mammals, but in a wide diversity of organisms. Of simple unicellular organisms that use phagocytosis to extract nutrients, to complex metazoans in which phagocytosis is essential for the innate defence system, as a first line of defence against invading pathogens, as well as for the clearance of damaged, dying or dead cells. Evolution has armed multicellular organisms with a range of receptors expressed on many cells that serve as the molecular basis to bring about phagocytosis, regardless of the organism or the specific physiological event concerned. Key to all phagocytic processes is the finely controlled rearrangement of the actin cytoskeleton, in which Ca(2+) signals play a major role. Ca(2+) is involved in cytoskeletal changes by affecting the actions of a number of contractile proteins, as well as being a cofactor for the activation of a number of intracellular signalling molecules, which are known to play important roles during the initiation, progression and resolution of the phagocytic process. In mammals, the requirement of Ca(2+) for the initial steps in phagocytosis, and the subsequent phagosome maturation, can be quite different depending on the type of cell and on the type of receptor that is driving phagocytosis. In this review we discuss the different receptors that mediate professional and non-professional phagocytosis, and discuss the role of Ca(2+) in the different steps of this complex process.
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35
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Lomakina E, Knauf PA, Schultz JB, Law FY, McGraw MD, Waugh RE. Activation of human neutrophil Mac-1 by anion substitution. Blood Cells Mol Dis 2009; 42:177-84. [PMID: 19246218 DOI: 10.1016/j.bcmd.2009.01.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2008] [Accepted: 01/06/2009] [Indexed: 12/18/2022]
Abstract
Substituting the medium chloride with glucuronate or glutamate causes a rapid, 10 to 30-fold, increase in the binding of the monoclonal antibody, CBRM1/5, which recognizes the high-affinity conformation of the Mac-1 integrin. This change is reflected in functional adhesion assays that show increased adhesion to ICAM-1 coated beads. Blocking antibodies indicate that the increased adhesion is almost entirely due to Mac-1. The inhibitor NPPB (100 microM) reduces Cl(-) efflux into low Cl(-) medium by 75%, and blocks increased CBRM1/5 binding after stimulation with fMLP or TNF-alpha, but has no effect on the anion substitution induced increase in CBRM1/5 binding or adhesion to immobilized ICAM-1. Thus, changes in external anion composition, not internal chloride or increases in Cl(-) efflux, are responsible for Mac-1 activation. This effect is substantial. The percentage of Mac-1 in the high affinity state approaches 100% in glutamate and 50% in glucuronate, a far greater response than what is observed after stimulation with fMLP.
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Affiliation(s)
- Elena Lomakina
- Department of Pharmacology and Physiology, School of Medicine, University of Rochester, Rochester, NY 14642, USA
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36
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Luo BH, Karanicolas J, Harmacek LD, Baker D, Springer TA. Rationally designed integrin beta3 mutants stabilized in the high affinity conformation. J Biol Chem 2008; 284:3917-24. [PMID: 19019827 DOI: 10.1074/jbc.m806312200] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Integrins are important cell surface receptors that transmit bidirectional signals across the membrane. It has been shown that a conformational change of the integrin beta-subunit headpiece (i.e. the beta I domain and the hybrid domain) plays a critical role in regulating integrin ligand binding affinity and function. Previous studies have used coarse methods (a glycan wedge, mutations in transmembrane contacts) to force the beta-subunit into either the open or closed conformation. Here, we demonstrate a detailed understanding of this conformational change by applying computational design techniques to select five amino acid side chains that play an important role in the energetic balance between the open and closed conformations of alphaIIbbeta3. Eight single-point mutants were designed at these sites, of which five bound ligands much better than wild type. Further, these mutants were found to be in a more extended conformation than wild type, suggesting that the conformational change at the ligand binding headpiece was propagated to the legs of the integrin. This detailed understanding of the conformational change will assist in the development of allosteric drugs that either stabilize or destabilize specific integrin conformations without occluding the ligand-binding site.
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Affiliation(s)
- Bing-Hao Luo
- Immune Disease Institute and Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115, USA
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37
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Dobreva ZG, Stanilova SA. The Immunomodulatory Activity of C3 Binding Glycoprotein (C3bgp) is Mediated by the Complement Receptor Type III and Mitogen-Activated Protein Kinase Signal Transduction Pathways. Immunopharmacol Immunotoxicol 2008; 29:549-62. [DOI: 10.1080/08923970701691017] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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38
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Mor-Cohen R, Rosenberg N, Landau M, Lahav J, Seligsohn U. Specific Cysteines in β3 Are Involved in Disulfide Bond Exchange-dependent and -independent Activation of αIIbβ3. J Biol Chem 2008; 283:19235-44. [DOI: 10.1074/jbc.m802399200] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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39
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Lee SH, Prince JE, Rais M, Kheradmand F, Ballantyne CM, Weitz-Schmidt G, Smith CW, Corry DB. Developmental control of integrin expression regulates Th2 effector homing. THE JOURNAL OF IMMUNOLOGY 2008; 180:4656-67. [PMID: 18354189 DOI: 10.4049/jimmunol.180.7.4656] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Integrin CD18, a component of the LFA-1 complex that also includes CD11a, is essential for Th2, but not Th1, cell homing, but the explanation for this phenomenon remains obscure. In this study, we investigate the mechanism by which Th2 effector responses require the LFA-1 complex. CD11a-deficient T cells showed normal in vitro differentiation and function. However, Th2 cell-dependent allergic lung disease was markedly reduced in CD11a null mice and wild-type mice given LFA-1 inhibitors, whereas control of infection with Leishmania major, a Th1-dependent response, was enhanced. In both disease models, recruitment of IL-4-, but not IFN-gamma-secreting cells to relevant organs was impaired, as was adhesion of Th2 cells in vitro. These diverse findings were explained by the markedly reduced expression of CD29, an alternate homing integrin, on Th2, but not Th1, cells, which precludes Th2 homing in the absence of CD11a. Thus, murine Th1 and Th2 cells use distinct integrins for homing, suggesting novel opportunities for integrin-based therapeutic intervention in diverse human ailments influenced by Th2 cells.
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Affiliation(s)
- Seung-Hyo Lee
- Department of Immunology, Baylor College of Medicine, Houston, TX 77030, USA
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40
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Sadhu C, Hendrickson L, Dick KO, Potter TG, Staunton DE. Novel tools for functional analysis of CD11c: activation-specific, activation-independent, and activating antibodies. J Immunoassay Immunochem 2008; 29:42-57. [PMID: 18080879 DOI: 10.1080/15321810701735062] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Functions and binding properties of four CD11c-specific mAbs are described here. The mAb 496B stimulated, while 496K inhibited ligand binding of CD11c. The stimulatory mAb, 496B, as well as the inhibitory mAbs BU15 and 496 K appear to act allosterically, as they do not bind the CD11c I domain. The mAb 3.9 bound preferentially to activated forms of CD11c and the binding was divalent cation dependent. CD11c binding to 3.9 recapitulates many of the integrin-ligand interactions. Our data suggest that 3.9 is a competitive antagonist, BU15 and 496K are allosteric antagonists, and 496B is an allosteric agonist of CD11c. These mAbs provide a set of tools to study the functions of the dendritic cell marker, CD11c.
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41
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Barthel SR, Johansson MW, McNamee DM, Mosher DF. Roles of integrin activation in eosinophil function and the eosinophilic inflammation of asthma. J Leukoc Biol 2007; 83:1-12. [PMID: 17906117 PMCID: PMC2859217 DOI: 10.1189/jlb.0607344] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Eosinophilic inflammation is a characteristic feature of asthma. Integrins are highly versatile cellular receptors that regulate extravasation of eosinophils from the postcapillary segment of the bronchial circulation to the airway wall and airspace. Such movement into the asthmatic lung is described as a sequential, multistep paradigm, whereby integrins on circulating eosinophils become activated, eosinophils tether in flow and roll on bronchial endothelial cells, integrins on rolling eosinophils become further activated as a result of exposure to cytokines, eosinophils arrest firmly to adhesive ligands on activated endothelium, and eosinophils transmigrate to the airway in response to chemoattractants. Eosinophils express seven integrin heterodimeric adhesion molecules: alpha 4 beta 1 (CD49d/29), alpha 6 beta 1 (CD49f/29), alpha M beta 2 (CD11b/18), alpha L beta 2 (CD11a/18), alpha X beta 2 (CD11c/18), alpha D beta2 (CD11d/18), and alpha 4 beta 7 (CD49d/beta 7). The role of these integrins in eosinophil recruitment has been elucidated by major advances in the understanding of integrin structure, integrin function, and modulators of integrins. Such findings have been facilitated by cellular experiments of eosinophils in vitro, studies of allergic asthma in humans and animal models in vivo, and crystal structures of integrins. Here, we elaborate on how integrins cooperate to mediate eosinophil movement to the asthmatic airway. Antagonists that target integrins represent potentially promising therapies in the treatment of asthma.
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Affiliation(s)
- Steven R. Barthel
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53706-1532
- Department of Medicine, University of Wisconsin-Madison, Madison, WI 53706-1532
| | - Mats W. Johansson
- Department of Medicine, University of Wisconsin-Madison, Madison, WI 53706-1532
| | - Dawn M. McNamee
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53706-1532
- Department of Medicine, University of Wisconsin-Madison, Madison, WI 53706-1532
| | - Deane F. Mosher
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53706-1532
- Department of Medicine, University of Wisconsin-Madison, Madison, WI 53706-1532
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42
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Orr Y, Taylor JM, Cartland S, Bannon PG, Geczy C, Kritharides L. Conformational activation of CD11b without shedding of L-selectin on circulating human neutrophils. J Leukoc Biol 2007; 82:1115-25. [PMID: 17675559 DOI: 10.1189/jlb.0906545] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Membrane-activated complex 1 (Mac-1; CD11b/CD18) is a beta(2) integrin implicated in the pathophysiology of neutrophil-mediated tissue injury whose functional capacity is determined by stimulus-induced conformational activation rather than up-regulation. Mac-1 up-regulation and conformational activation, together with shedding of L-selectin, are reported after in vitro neutrophil activation. However, their regulation on circulating human neutrophils during acute inflammation is unclear. Using flow cytometry, we investigated neutrophil expression of Mac-1, its activation-reporter neo-epitope CBRM1/5, and L-selectin during the inflammatory stimulus of cardiac surgery. A subpopulation of circulating neutrophils expressed CBRM1/5 (CBRM1/5+) under basal conditions (6.28+/-2.59%) and was persistently expanded (9.95+/-4.0%-15.2+/-4.2%; P<0.0001) peri-operatively, whereas total CD11b expression increased only transiently, intra-operatively. L-selectin expression was unchanged on CBRM1/5+ neutrophils, and soluble L-selectin levels decreased intra-operatively (P<0.01), indicating that L-selectin was not shed. Increased CBRM1/5 expression without L-selectin loss or CD11b up-regulation was replicated in vitro by neutrophil stimulation with IL-8, C3a, and platelet-activating factor. Heparin, a known CD11b ligand, which is administered during cardiac surgery, markedly reduced neutrophil expression of conformationally active CD11b in vivo and in vitro, identifying a potential mechanism for its anti-inflammatory properties. We conclude that conformational activation of CD11b occurs on circulating neutrophils in vivo and can occur in the absence of CD11b up-regulation and L-selectin shedding.
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Affiliation(s)
- Y Orr
- Centre for Vascular Research, School of Medical Sciences, 4th Floor Wallace Wurth Building, The University of New South Wales, Kensington, NSW, Australia
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43
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Shimaoka M, Kim M, Cohen EH, Yang W, Astrof N, Peer D, Salas A, Ferrand A, Springer TA. AL-57, a ligand-mimetic antibody to integrin LFA-1, reveals chemokine-induced affinity up-regulation in lymphocytes. Proc Natl Acad Sci U S A 2006; 103:13991-6. [PMID: 16963559 PMCID: PMC1599901 DOI: 10.1073/pnas.0605716103] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Affinity of integrin lymphocyte function-associated antigen 1 (LFA-1) is enhanced by conformational changes from the low-affinity closed form to the high-affinity (HA) open form of the ligand-binding inserted (I) domain as shown by work with purified I domains. However, affinity up-regulation of LFA-1 on the cell surface by physiological agonists such as chemokines has yet to be demonstrated by monovalent reagents. We characterize a mAb, AL-57 (activated LFA-1 clone 57), that has been developed by phage display that selectively targets the HA open conformation of the LFA-1 I domain. AL-57 discriminates among low-affinity, intermediate-affinity, and HA states of LFA-1. Furthermore, AL-57 functions as a ligand mimetic that binds only upon activation and requires Mg2+ for binding. Compared with the natural ligand intercellular adhesion molecule-1, AL-57 shows a tighter binding to the open I domain and a 250-fold slower off rate. Monovalent Fab AL-57 demonstrates affinity increases on a subset (approximately 10%) of lymphocyte cell surface LFA-1 molecules upon stimulation with CXCL-12 (CXC chemokine ligand 12). Affinity up-regulation correlates with global conformational changes of LFA-1 to the extended form. Affinity increase stimulated by CXCL-12 is transient and peaks 2 to 5 min after stimulation.
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Affiliation(s)
- Motomu Shimaoka
- *CBR Institute for Biomedical Research and
- Departments of Anesthesia and
| | - Minsoo Kim
- Division of Surgical Research, Rhode Island Hospital and Brown University School of Medicine, 593 Eddy Street, Middlehouse 207, Providence, RI 02903; and
| | | | - Wei Yang
- *CBR Institute for Biomedical Research and
- **Pathology, Harvard Medical School, 200 Longwood Avenue, Boston, MA 02115
| | - Nathan Astrof
- *CBR Institute for Biomedical Research and
- **Pathology, Harvard Medical School, 200 Longwood Avenue, Boston, MA 02115
| | - Dan Peer
- *CBR Institute for Biomedical Research and
- Departments of Anesthesia and
| | - Azucena Salas
- *CBR Institute for Biomedical Research and
- **Pathology, Harvard Medical School, 200 Longwood Avenue, Boston, MA 02115
| | - Audrey Ferrand
- *CBR Institute for Biomedical Research and
- **Pathology, Harvard Medical School, 200 Longwood Avenue, Boston, MA 02115
| | - Timothy A. Springer
- *CBR Institute for Biomedical Research and
- **Pathology, Harvard Medical School, 200 Longwood Avenue, Boston, MA 02115
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44
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Barthel SR, Annis DS, Mosher DF, Johansson MW. Differential engagement of modules 1 and 4 of vascular cell adhesion molecule-1 (CD106) by integrins alpha4beta1 (CD49d/29) and alphaMbeta2 (CD11b/18) of eosinophils. J Biol Chem 2006; 281:32175-87. [PMID: 16943205 DOI: 10.1074/jbc.m600943200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
We have studied adhesion of eosinophils to various forms of vascular cell adhesion molecule 1 (VCAM-1, CD106), an integrin counter-receptor implicated in eosinophil recruitment to the airway in asthma. Full-length 7d-VCAM-1, with seven immunoglobulin-like modules, contains integrin-binding sites in modules 1 and 4. The alternatively spliced six-module protein, 6d-VCAM-1, lacks module 4. In static assays, unactivated purified human blood eosinophils adhered similarly to recombinant soluble human 6d-VCAM-1 and 7d-VCAM-1 coated onto polystyrene microtiter wells. Further experiments, however, revealed differences in recognition of modules 1 and 4. Antibody blocking indicated that eosinophil adhesion to 6d-VCAM-1 or a VCAM-1 construct containing only modules 1-3, 1-3VCAM-1, is mediated by alpha4beta1 (CD49d/29), whereas adhesion to a construct containing modules 4-7, 4-7VCAM-1, is mediated by bothalpha4beta1 andalphaMbeta2 (CD11b/18). Inhibitors of phosphoinositide 3-kinase, which block adhesion of eosinophils mediated by alphaMbeta2, blocked adhesion to 4-7VCAM-1 but had no effect on adhesion to 6d-VCAM-1. Consistent with the antibody and pharmacological blocking experiments, eosinophilic leukemic cell lines lacking alphaMbeta2 did not adhere to 4-7VCAM-1 but did adhere to 6d-VCAM-1 or 1-3VCAM-1. Activation of eosinophils by interleukin (IL)-5 enhanced static adhesion to 6d-VCAM-1, 7d-VCAM-1, or 4-7VCAM-1; IL-5-enhanced adhesion to all 3 constructs was blocked by anti-alphaMbeta2. Adhesion of unstimulated eosinophils to 7d-VCAM-1 under flow conditions was inhibited by anti-alpha4 or anti-alphaM. IL-5 treatment decreased eosinophil adhesion to 7d-VCAM-1 under flow, and anti-alphaM had the paradoxical effect of increasing adhesion. These results demonstrate that alphaMbeta2 modulatesalpha4beta1-mediated eosinophil adhesion to VCAM-1 under both static and flow conditions.
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Affiliation(s)
- Steven R Barthel
- Departments of Biomolecular Chemistry and Medicine, University of Wisconsin, 4285A Medical Sciences Center, 1300 University Avenue, Madison, WI 53706-1532, USA
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45
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Huang L, Shimaoka M, Rondon IJ, Roy I, Chang Q, Po M, Dransfield DT, Ladner RC, Edge ASB, Salas A, Wood CR, Springer TA, Cohen EH. Identification and characterization of a human monoclonal antagonistic antibody AL-57 that preferentially binds the high-affinity form of lymphocyte function-associated antigen-1. J Leukoc Biol 2006; 80:905-14. [PMID: 16888085 PMCID: PMC1712386 DOI: 10.1189/jlb.1105649] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
LFA-1 (alpha(L)beta(2)) mediates cell-cell and cell-extracellular matrix adhesions essential for immune and inflammatory responses. One critical mechanism regulating LFA-1 activity is the conformational change of the ligand-binding alpha(L) I domain from low-affinity (LA), closed form, to the high-affinity (HA), open form. Most known integrin antagonists bind both forms. Antagonists specific for the HA alpha(L) I domain have not been described. Here, we report the identification and characterization of a human antibody AL-57, which binds to the alpha(L) I domain in a HA but not LA conformation. AL-57 was discovered by selection from a human Fab-displaying library using a locked-open HA I domain as target. AL-57 Fab-phage bound HA I domain-expressing K562 cells (HA cells) in a Mg(2+)-dependent manner. AL-57 IgG also bound HA cells and PBMCs, activated by Mg(2+)/EGTA, PMA, or DTT. The binding profile of AL-57 IgG on PBMCs was the same as that of ICAM-1, the main ligand of LFA-1. In contrast, an anti-alpha(L) murine mAb MHM24 did not distinguish between the HA and LA forms. Moreover, AL-57 IgG blocked ICAM-1 binding to HA cells with a potency greater than MHM24. It also inhibited ICAM-1 binding to PBMCs, blocked adhesion of HA cells to keratinocytes, and inhibited PHA-induced lymphocyte proliferation with potencies comparable with MHM24. These results indicate that specifically targeting the HA I domain is sufficient to inhibit LFA-1-mediated, adhesive functions. AL-57 represents a therapeutic candidate for treatment of inflammatory and autoimmune diseases.
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Affiliation(s)
- Lili Huang
- Dyax Corporation, Cambridge, MA 02139, USA.
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46
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Frick C, Odermatt A, Zen K, Mandell KJ, Edens H, Portmann R, Mazzucchelli L, Jaye DL, Parkos CA. Interaction of ICAM-1 with beta 2-integrin CD11c/CD18: characterization of a peptide ligand that mimics a putative binding site on domain D4 of ICAM-1. Eur J Immunol 2006; 35:3610-21. [PMID: 16252253 DOI: 10.1002/eji.200425914] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The integrin CD11c/CD18 plays a role in leukocyte and cell matrix adhesion and is highly expressed in certain hematopoietic malignancies. To better characterize ligand binding properties, we panned random peptide phage-display libraries over purified CD11c/CD18. We identified a phage expressing the circular peptide C-GRWSGWPADL-C. C-GRWSGWPADL-C phage bound specifically to CD11c/CD18 expressing monocytes but not CD11c/CD18 negative lymphocytes and showed 5 x 10(3)-fold higher binding to purified CD11c/CD18 than control phage, without binding to CD11b/CD18. Peptide sequence analysis revealed a similar sequence in domain D5 of ICAM-1 and an alternative, phase-shifted motif in domain D4. Surface plasmon resonance experiments demonstrated direct interaction of ICAM-1 and CD11c/CD18. A soluble fusion protein containing the extracellular domain of ICAM-1 abolished C-GRWSGWPADL-C phage binding to CD11c/CD18. Moreover, synthetic monomeric circular peptide C-GRWSGWPADL-C bound specifically to CD11c/CD18 and inhibited ICAM-1 binding. Its rather low binding affinity and inability to displace pentavalent C-GRWSGWPADL-C phage from CD11c/CD18 suggests that a multimeric display of the selected peptide is essential for high affinity binding. Using ICAM-1 deletion constructs, we showed that domain D4 is required for interaction with CD11c/CD18, suggesting that C-GRWSGWPADL-C phage binds specifically to CD11c/CD18 by structurally mimicking the interaction site on D4 of ICAM-1.
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Affiliation(s)
- Christoph Frick
- Department of Nephrology and Hypertension, Department of Clinical Research,University of Berne, Berne, Switzerland
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47
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Li B, Allendorf DJ, Hansen R, Marroquin J, Ding C, Cramer DE, Yan J. Yeast β-Glucan Amplifies Phagocyte Killing of iC3b-Opsonized Tumor Cells via Complement Receptor 3-Syk-Phosphatidylinositol 3-Kinase Pathway. THE JOURNAL OF IMMUNOLOGY 2006; 177:1661-9. [PMID: 16849475 DOI: 10.4049/jimmunol.177.3.1661] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Anti-tumor mAbs hold promise for cancer therapy, but are relatively inefficient. Therefore, there is a need for agents that might amplify the effectiveness of these mAbs. One such agent is beta-glucan, a polysaccharide produced by fungi, yeast, and grains, but not mammalian cells. Beta-glucans are bound by C receptor 3 (CR3) and, in concert with target-associated complement fragment iC3b, elicit phagocytosis and killing of yeast. Beta-glucans may also promote killing of iC3b-opsonized tumor cells engendered by administration of anti-tumor mAbs. In this study, we report that tumor-bearing mice treated with a combination of beta-glucan and an anti-tumor mAb show almost complete cessation of tumor growth. This activity evidently derives from a 25-kDa fragment of beta-glucan released by macrophage processing of the parent polysaccharide. This fragment, but not parent beta-glucan, binds to neutrophil CR3, induces CBRM 1/5 neoepitope expression, and elicits CR3-dependent cytotoxicity. These events require phosphorylation of the tyrosine kinase, Syk, and consequent PI3K activation because beta-glucan-mediated CR3-dependent cytotoxicity is greatly decreased by inhibition of these signaling molecules. Thus, beta-glucan enhances tumor killing through a cascade of events, including in vivo macrophage cleavage of the polysaccharide, dual CR3 ligation, and CR3-Syk-PI3K signaling. These results are important inasmuch as beta-glucan, an agent without evident toxicity, may be used to amplify tumor cell killing and may open new opportunities in the immunotherapy of cancer.
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Affiliation(s)
- Bing Li
- Tumor Immunobiology Program, James Graham Brown Cancer Center, University of Louisville, Louisville, KY 40202, USA
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48
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Barthel SR, Jarjour NN, Mosher DF, Johansson MW. Dissection of the hyperadhesive phenotype of airway eosinophils in asthma. Am J Respir Cell Mol Biol 2006; 35:378-86. [PMID: 16601240 PMCID: PMC1550734 DOI: 10.1165/rcmb.2006-0027oc] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Asthma is characterized by appearance of eosinophils in the airway. Eosinophils purified from the airway 48 h after segmental antigen challenge are described as exhibiting greater adhesion to albumin-coated surfaces via an unidentified beta2 integrin and increased expression of alphaMbeta2 (CD11b/18) compared with purified blood eosinophils. We have investigated the determinants of this hyperadhesive phenotype. Airway eosinophils exhibited increased reactivity with the CBRM1/5 anti-alphaM activation-sensitive antibody as well as enhanced adhesion to VCAM-1 (CD106) and diverse ligands, including albumin, ICAM-1 (CD54), fibrinogen, and vitronectin. Purified blood eosinophils did not adhere to the latter diverse ligands. Enhanced adhesion of airway eosinophils was blocked by anti-alphaMbeta2. Podosomes, structures implicated in cell movement and proteolysis of matrix proteins, were larger and more common on airway eosinophils adherent to VCAM-1 when compared with blood eosinophils. Incubation of blood eosinophils with IL-5 replicated the phenotype of airway eosinophils. That is, IL-5 enhanced recognition of alphaM by CBRM1/5; stimulated alphaMbeta2-mediated adhesion to VCAM-1, albumin, ICAM-1, fibrinogen, and vitronectin; and increased podosome formation on VCAM-1. Thus, the hyperadhesion of airway eosinophils after antigen challenge is mediated by upregulated and activated alphaMbeta2.
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Affiliation(s)
- Steven R Barthel
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, 4285A Medical Sciences Center, 1300 University Avenue, Madison, Wisconsin 53706-1532, USA
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49
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Staunton DE, Lupher ML, Liddington R, Gallatin WM. Targeting integrin structure and function in disease. Adv Immunol 2006; 91:111-57. [PMID: 16938539 DOI: 10.1016/s0065-2776(06)91003-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Initially linked to the pathogenesis of inflammatory and hematologic diseases, integrins have become validated drug targets with the approval of five drugs. Moreover, there are several promising drug candidates in preclinical and clinical stages of development for multiple clinical indications. Integrins are attractive drug targets as their antagonism can block several steps in disease progression or maintenance. Integrin inhibitors can block the proliferation, migration, or tissue localization of inflammatory, angiogenic, and tumor cells, as well as signaling and gene expression contributing to disease. There has been a rapid increase in the elucidation of integrin structure, their allosteric mechanisms of bidirectional signaling, and the structure of complexes with drugs. This information brings greater focus to how integrins support various cellular functions and how they have been and may be targeted to develop novel drugs. Here we review conformational switches, including an internal ligand, which allosterically regulate the transition from low- to high-affinity ligand binding. We address some of the successes, disappointments, and challenges in targeting competitive or allosteric sites to develop therapeutics. We also discuss new opportunities, including a structure-based approach to discover novel drugs to treat inflammatory and other diseases. This approach targets structural relatives of the von Willebrand factor A-domain present in integrins and many functionally diverse proteins.
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50
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Heit B, Colarusso P, Kubes P. Fundamentally different roles for LFA-1, Mac-1 and α4-integrin in neutrophil chemotaxis. J Cell Sci 2005; 118:5205-20. [PMID: 16249234 DOI: 10.1242/jcs.02632] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Although the LFA-1, Mac-1 and α4 integrins are required for chemotaxis, it is unknown how they are regulated or what specific role they play. Previously we demonstrated that fMLP and IL-8 induce chemotaxis via the p38 MAPK and phosphoinositide 3-kinase (PI3K) pathways, respectively. Here we show that these chemoattractants also activate and use Mac-1 and LFA-1 in a differential manner during chemotaxis. Using integrin-specific substrata, we demonstrate that cell movement in response to IL-8 is mediated by Mac-1, whereas LFA-1 is required for directional migration. By contrast, chemotaxis to fMLP requires Mac-1 for cell movement, whereas LFA-1 and α4-integrin are required for directional migration. On serum protein, which contains ligands for LFA-1, Mac-1 and α4-integrin, chemotaxis to fMLP is dependent on Mac-1, whereas chemotaxis to IL-8 is dependent on LFA-1. These results suggest that Mac-1 is the dominant integrin involved in chemotaxis to fMLP, and LFA-1 is the dominant integrin involved in chemotaxis to IL-8. Consistent with these observations, higher quantities of high-affinity Mac-1 are found on cells chemotaxing to fMLP then on cells chemotaxing to IL-8. Moreover, a much larger quantity of clustered LFA-1 was found on cells migrating to IL-8 compared to cells moving towards fMLP. When cells are presented with competing gradients of fMLP and IL-8, they preferentially migrate towards fMLP and activate/utilize integrins in a manner identical to fMLP alone. Under the same conditions, p38 MAPK inhibition abolishes the preferential migration to fMLP; instead, the cells migrate preferentially towards IL-8. The activation and utilization of integrins under these conditions are consistent with patterns observed with IL-8 alone. Together, these data suggest that fMLP and IL-8 differentially activate integrins for use during chemotaxis, that p38 MAPK is a major mediator in the activation and utilization of integrins, and selective integrin activation occurs during chemotaxis between opposing gradients.
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Affiliation(s)
- Bryan Heit
- Immunology Research Group, Department of Physiology and Biophysics, Faculty of Medicine, University of Calgary, 3330 Hospital Drive, Alberta T2N 4N1, Canada
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