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Ballet R, LaJevic M, Huskey-Mullin N, Roach R, Brulois K, Huang Y, Saeed MA, Dang HX, Pachynski RK, Wilson E, Butcher EC, Zabel BA. Chemerin triggers migration of a CD8 T cell subset with natural killer cell functions. Mol Ther 2023; 31:2887-2900. [PMID: 37641406 PMCID: PMC10556222 DOI: 10.1016/j.ymthe.2023.08.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 07/31/2023] [Accepted: 08/25/2023] [Indexed: 08/31/2023] Open
Abstract
The recruitment of cells with effector functions into the tumor microenvironment holds potential for delaying cancer progression. We show that subsets of human CD28-effector CD8 T cells, CCR7- CD45RO+ effector memory, and CCR7- CD45RO- effector memory RA phenotypes, express the chemerin receptor CMKLR1 and bind chemerin via the receptor. CMKLR1-expressing human CD8 effector memory T cells present gene, protein, and cytotoxic features of NK cells. Active chemerin promotes chemotaxis of CMKLR1-expressing CD8 effector memory cells and triggers activation of the α4β1 integrin. In an experimental prostate tumor mouse model, chemerin expression is downregulated in the tumor microenvironment, which is associated with few tumor-infiltrating CD8+ T cells, while forced overexpression of chemerin by mouse prostate cancer cells leads to an accumulation of intra-tumor CD8+ T cells. Furthermore, α4 integrin blockade abrogated the chemerin-dependent recruitment of CD8+ T effector memory cells into implanted prostate tumors in vivo. The results identify a role for chemerin:CMKLR1 in defining a specialized NK-like CD8 T cell, and suggest the use of chemerin-dependent modalities to target effector CMKLR1-expressing T cells to the tumor microenvironment for immunotherapeutic purposes.
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Affiliation(s)
- Romain Ballet
- Palo Alto Veterans Institute for Research (PAVIR), Veterans Affairs Palo Alto Health Care System (VAPAHCS), Palo Alto, CA 94304, USA; Laboratory of Immunology and Vascular Biology, Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Melissa LaJevic
- Palo Alto Veterans Institute for Research (PAVIR), Veterans Affairs Palo Alto Health Care System (VAPAHCS), Palo Alto, CA 94304, USA; Laboratory of Immunology and Vascular Biology, Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | | | - Rachel Roach
- Pfizer Centers for Therapeutic Innovation, La Jolla, CA 92121, USA
| | - Kevin Brulois
- Palo Alto Veterans Institute for Research (PAVIR), Veterans Affairs Palo Alto Health Care System (VAPAHCS), Palo Alto, CA 94304, USA; Laboratory of Immunology and Vascular Biology, Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Ying Huang
- Pfizer Centers for Therapeutic Innovation, La Jolla, CA 92121, USA
| | - Muhammad A Saeed
- Department of Medicine, Washington University School of Medicine, St Louis, MO 63130, USA
| | - Ha X Dang
- Department of Medicine, Washington University School of Medicine, St Louis, MO 63130, USA
| | - Russell K Pachynski
- Department of Medicine, Washington University School of Medicine, St Louis, MO 63130, USA
| | - Elizabeth Wilson
- Pfizer Centers for Therapeutic Innovation, La Jolla, CA 92121, USA
| | - Eugene C Butcher
- Laboratory of Immunology and Vascular Biology, Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Brian A Zabel
- Palo Alto Veterans Institute for Research (PAVIR), Veterans Affairs Palo Alto Health Care System (VAPAHCS), Palo Alto, CA 94304, USA; Laboratory of Immunology and Vascular Biology, Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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2
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Allenby MC, Okutsu N, Brailey K, Guasch J, Zhang Q, Panoskaltsis N, Mantalaris A. A spatiotemporal microenvironment model to improve design of a 3D bioreactor for red cell production. Tissue Eng Part A 2021; 28:38-53. [PMID: 34130508 DOI: 10.1089/ten.tea.2021.0028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Cellular microenvironments provide stimuli including paracrine and autocrine growth factors and physico-chemical cues, which support efficient in vivo cell production unmatched by current in vitro biomanufacturing platforms. While three-dimensional (3D) culture systems aim to recapitulate niche architecture and function of the target tissue/organ, they are limited in accessing spatiotemporal information to evaluate and optimize in situ cell/tissue process development. Herein, a mathematical modelling framework is parameterized by single-cell phenotypic imaging and multiplexed biochemical assays to simulate the non-uniform tissue distribution of nutrients/metabolites and growth factors in cell niche environments. This model is applied to a bone marrow mimicry 3D perfusion bioreactor containing dense stromal and hematopoietic tissue with limited red blood cell (RBC) egress. The model characterized an imbalance between endogenous cytokine production and nutrient starvation within the microenvironmental niches, and recommended increased cell inoculum density and enhanced medium exchange, guiding the development of a miniaturized prototype bioreactor. The second-generation prototype improved the distribution of nutrients and growth factors and supported a 50-fold increase in RBC production efficiency. This image-informed bioprocess modelling framework leverages spatiotemporal niche information to enhance biochemical factor utilization and improve cell manufacturing in 3D systems.
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Affiliation(s)
- Mark Colin Allenby
- Queensland University of Technology, 1969, Institute of Health and Biomedical Innovation (IHBI), Kelvin Grove, Queensland, Australia.,Imperial College London, 4615, Department of Chemical Engineering, London, London, United Kingdom of Great Britain and Northern Ireland;
| | - Naoki Okutsu
- Imperial College London, 4615, Department of Chemical Engineering, London, London, United Kingdom of Great Britain and Northern Ireland;
| | - Kate Brailey
- Imperial College London, 4615, Department of Chemical Engineering, London, London, United Kingdom of Great Britain and Northern Ireland;
| | - Joana Guasch
- Imperial College London, 4615, Department of Chemical Engineering, London, London, United Kingdom of Great Britain and Northern Ireland;
| | - Qiming Zhang
- Imperial College London, 4615, Department of Chemical Engineering, London, London, United Kingdom of Great Britain and Northern Ireland;
| | - Nicki Panoskaltsis
- Emory University, 1371, Winship Cancer Institute, Department of Hematology & Medical Oncology, Atlanta, Georgia, United States.,Imperial College London, 4615, Department of Haematology, London, London, United Kingdom of Great Britain and Northern Ireland;
| | - Athanasios Mantalaris
- Georgia Institute of Technology, 1372, BME, Atlanta, Georgia, United States.,Imperial College London, 4615, Department of Chemical Engineering, London, London, United Kingdom of Great Britain and Northern Ireland;
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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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4
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Amani A, Shamloo A, Barzegar S, Forouzandehmehr M. Effect of Material and Population on the Delivery of Nanoparticles to an Atherosclerotic Plaque: A Patient-specific In Silico Study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:1551-1562. [PMID: 33465311 DOI: 10.1021/acs.langmuir.0c03158] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Coronary artery disease (CAD) is the prevalent reason of mortality all around the world. Targeting CAD, specifically atherosclerosis, with controlled delivery of micro and nanoparticles, as drug carriers, is a very proficient approach. In this work, a patient-specific and realistic model of an atherosclerotic plaque in the left anterior descending (LAD) artery was created by image-processing of CT-scan images and implementing a finite-element mesh. Next, a fluid-solid interaction simulation considering the physiological boundary conditions was conducted. By considering the simulated force fields and particle-particle interactions, the correlation between injected particles at each cardiac cycle and the surface density of adhered particles over the atherosclerotic plaque (SDP) were examined. For large particles (800 and 1000 nm) the amount of SDP on the plaque increased significantly when the number of the injected particles became higher. However, by increasing the number of the injected particles, for the larger particles (800 and 1000 nm) the increase in SDP was about 50% greater than that of the smaller ones (400 and 600 nm). Furthermore, for constant number of particles, depending on their size, different trends in SDP were observed. Subsequently, the distribution and adhesion of metal-based nanoparticles including SiO2, Fe3O4, NiO2, silver and gold with different properties were simulated. The injection of metal particles with medium density among the considered particles resulted in the highest SDP. Remarkably, the affinity, the geometrical features, and the biophysical factors involved in the adhesion outweighed the effect of difference in the density of particles on the SDP. Finally, the consideration of the lift force in the simulations significantly reduced the SDP and consistently decreased the particle residence time in the studied domain.
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Affiliation(s)
- Ali Amani
- School of Mechanical Engineering, Sharif University of Technology, Tehran 11155-9567, Iran
| | - Amir Shamloo
- School of Mechanical Engineering, Sharif University of Technology, Tehran 11155-9567, Iran
| | - Saeid Barzegar
- School of Mechanical Engineering, Sharif University of Technology, Tehran 11155-9567, Iran
| | - Mohamadamin Forouzandehmehr
- School of Mechanical Engineering, Sharif University of Technology, Tehran 11155-9567, Iran
- Faculty of Medicine and Health Technology, Tampere University, Tampere, FI-33520, Finland
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5
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Zanetti C, Krause DS. "Caught in the net": the extracellular matrix of the bone marrow in normal hematopoiesis and leukemia. Exp Hematol 2020; 89:13-25. [PMID: 32755619 DOI: 10.1016/j.exphem.2020.07.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 07/28/2020] [Accepted: 07/30/2020] [Indexed: 12/14/2022]
Abstract
The influence of the bone marrow microenvironment on normal hematopoiesis, but also leukemia, has largely been accepted. However, the focus has been predominantly on the role of various cell types or cytokines maintaining hematopoietic stem cells or protecting leukemia stem cells from different therapies. A frequently overlooked component of the bone marrow microenvironment is the extracellular matrix, which not only provides a mechanical scaffold, but also serves as a source of growth factors. We discuss here how extracellular matrix proteins directly or indirectly modulate hematopoietic stem cell physiology and influence leukemia progression. It is hoped that existing and future studies on this topic may propel forward the possibility of augmenting normal hematopoiesis and improving therapies for leukemia, for instance, by targeting of the extracellular matrix in the bone marrow.
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Affiliation(s)
- Costanza Zanetti
- Georg-Speyer-Haus, Institute for Tumor Biology and Experimental Therapy, Frankfurt am Main, Germany
| | - Daniela S Krause
- German Cancer Research Center (DKFZ), Heidelberg, Germany; German Cancer Consortium (DKTK), Germany; Frankfurt Cancer Institute, Frankfurt, Germany; Faculty of Medicine, Johann Wolfgang Goethe University, Frankfurt, Germany.
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6
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Sestito C, Brevé JJP, van Eggermond MCJA, Killestein J, Teunissen CE, van Rossum J, Wilhelmus MMM, Drukarch B, van den Elsen PJ, van Dam AM. Monocyte-derived tissue transglutaminase in multiple sclerosis patients: reflecting an anti-inflammatory status and function of the cells? J Neuroinflammation 2017; 14:257. [PMID: 29268771 PMCID: PMC5740592 DOI: 10.1186/s12974-017-1035-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 12/11/2017] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Leukocyte infiltration into the central nervous system is an important feature of multiple sclerosis (MS) pathology. Among the infiltrating cells, monocytes comprise the largest population and are considered to play a dual role in the course of the disease. The enzyme tissue transglutaminase (TG2), produced by monocytes, plays a central role in monocyte adhesion/migration in animal models of MS. In the present study, we questioned whether TG2 expression is altered in monocytes from MS patients compared to healthy control (HC) subjects. Moreover, we determined the inflammatory status of these TG2-expressing monocytes, what inflammatory factor regulates TG2 expression, and whether TG2 can functionally contribute to their adhesion/migration processes. METHODS Primary human monocytes from MS patients and HC subjects were collected, RNA isolated and subjected to qPCR analysis. Human THP-1 monocytes were lentivirally transduced with TG2 siRNA or control and treated with various cytokines. Subsequently, mRNA levels of inflammatory factors, adhesion properties, and activity of RhoA were analyzed in interleukin (IL)-4-treated monocytes. RESULTS TG2 mRNA levels are significantly increased in monocytes derived from MS patients compared to HC subjects. In addition, correlation analyses indicated that TG2-expressing cells display a more anti-inflammatory, migratory profile in MS patients. Using THP-1 monocytes, we observed that IL-4 is a major trigger of TG2 expression in these cells. Furthermore, knockdown of TG2 expression leads to a pro-inflammatory profile and reduced adhesion/migration properties of IL-4-treated monocytes. CONCLUSIONS TG2-expressing monocytes in MS patients have a more anti-inflammatory profile. Furthermore, TG2 mediates IL-4-induced anti-inflammatory status in THP-1 monocytes, adhesion, and cytoskeletal rearrangement in vitro. We thus propose that IL-4 upregulates TG2 expression in monocytes of MS patients, driving them into an anti-inflammatory status.
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Affiliation(s)
- Claudia Sestito
- Department of Anatomy and Neurosciences, Amsterdam Neuroscience, VU University Medical Center, Postbus 7057, 1007 MB, Amsterdam, the Netherlands.,Present Address: Brain Plasticity Group, Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, Amsterdam, the Netherlands
| | - John J P Brevé
- Department of Anatomy and Neurosciences, Amsterdam Neuroscience, VU University Medical Center, Postbus 7057, 1007 MB, Amsterdam, the Netherlands
| | - Marja C J A van Eggermond
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, the Netherlands
| | - Joep Killestein
- Department of Neurology, VU University Medical Center, Amsterdam, the Netherlands
| | - Charlotte E Teunissen
- Department of Clinical Chemistry, VU University Medical Center, Amsterdam, the Netherlands
| | - Joram van Rossum
- Department of Neurology, VU University Medical Center, Amsterdam, the Netherlands
| | - Micha M M Wilhelmus
- Department of Anatomy and Neurosciences, Amsterdam Neuroscience, VU University Medical Center, Postbus 7057, 1007 MB, Amsterdam, the Netherlands
| | - Benjamin Drukarch
- Department of Anatomy and Neurosciences, Amsterdam Neuroscience, VU University Medical Center, Postbus 7057, 1007 MB, Amsterdam, the Netherlands
| | - Peter J van den Elsen
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, the Netherlands.,Department of Pathology, VU University Medical Center, Amsterdam, the Netherlands
| | - Anne-Marie van Dam
- Department of Anatomy and Neurosciences, Amsterdam Neuroscience, VU University Medical Center, Postbus 7057, 1007 MB, Amsterdam, the Netherlands.
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7
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Avci S, Gur-Cohen S, Avemaria F, Lapidot T. Adhesion Assay for Murine Bone Marrow Hematopoietic Stem Cells. Bio Protoc 2017; 7:e2135. [PMID: 34458456 DOI: 10.21769/bioprotoc.2135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 11/22/2016] [Accepted: 01/21/2017] [Indexed: 11/02/2022] Open
Abstract
Hematopoietic stem cells (HSCs) are defined by their functional abilities to self-renew and to give rise to all mature blood and immune cell types throughout life. Most HSCs are retained in a non-motile quiescent state within a specialized protective microenvironment in the bone marrow (BM) termed the niche. HSCs are typically distinguished from other adult stem cells by their motility capacity. Movement of HSCs across the physical barrier of the marrow extracellular matrix and blood vessel endothelial cells is facilitated by suppression of adhesion interactions, which are essential to preserve the stem cells retained within their BM niches. Importantly, homing of HSCs to the BM following clinical transplantation is a crucial first step for the repopulation of ablated BM as in the case of curative treatment strategies for hematologic malignancies. The homing process ends with selective access and anchorage of HSCs to their specialized niches within the BM. Adhesion molecules are targets to either enhance homing in cases of stem cell transplantation or reduce BM retention to harvest mobilized HSCs from the blood of matched donors. A major adhesion protein which is functionally expressed on HSCs and is involved in their homing and retention is the integrin alpha4beta1 (Very late antigen-4; VLA4). In this protocol we introduce an adhesion assay optimized for VLA4 expressing murine bone marrow stem cells. This assay quantifies adherent HSCs by flow cytometry with HSC enriching cell surface markers subsequent to the isolation of VLA4 expressing adherent cells.
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Affiliation(s)
- Seymen Avci
- Weizmann Institute of Science, Immunology department, Rehovot, Israel
| | - Shiri Gur-Cohen
- Weizmann Institute of Science, Immunology department, Rehovot, Israel
| | | | - Tsvee Lapidot
- Weizmann Institute of Science, Immunology department, Rehovot, Israel
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8
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Lu L, Lin C, Yan Z, Wang S, Zhang Y, Wang S, Wang J, Liu C, Chen J. Kindlin-3 Is Essential for the Resting α4β1 Integrin-mediated Firm Cell Adhesion under Shear Flow Conditions. J Biol Chem 2016; 291:10363-71. [PMID: 26994136 DOI: 10.1074/jbc.m116.717694] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Indexed: 11/06/2022] Open
Abstract
Integrin-mediated rolling and firm cell adhesion are two critical steps in leukocyte trafficking. Integrin α4β1 mediates a mixture of rolling and firm cell adhesion on vascular cell adhesion molecule-1 (VCAM-1) when in its resting state but only supports firm cell adhesion upon activation. The transition from rolling to firm cell adhesion is controlled by integrin activation. Kindlin-3 has been shown to bind to integrin β tails and trigger integrin activation via inside-out signaling. However, the role of kindlin-3 in regulating resting α4β1-mediated cell adhesion is not well characterized. Herein we demonstrate that kindlin-3 was required for the resting α4β1-mediated firm cell adhesion but not rolling adhesion. Knockdown of kindlin-3 significantly decreased the binding of kindlin-3 to β1 and down-regulated the binding affinity of the resting α4β1 to soluble VCAM-1. Notably, it converted the resting α4β1-mediated firm cell adhesion to rolling adhesion on VCAM-1 substrates, increased cell rolling velocity, and impaired the stability of cell adhesion. By contrast, firm cell adhesion mediated by Mn(2+)-activated α4β1 was barely affected by knockdown of kindlin-3. Structurally, lack of kindlin-3 led to a more bent conformation of the resting α4β1. Thus, kindlin-3 plays an important role in maintaining a proper conformation of the resting α4β1 to mediate both rolling and firm cell adhesion. Defective kindlin-3 binding to the resting α4β1 leads to a transition from firm to rolling cell adhesion on VCAM-1, implying its potential role in regulating the transition between integrin-mediated rolling and firm cell adhesion.
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Affiliation(s)
- Ling Lu
- From the State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China and
| | - ChangDong Lin
- From the State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China and
| | - ZhanJun Yan
- The Second Affiliated Hospital of Soochow University, Suzhou 215004, China
| | - Shu Wang
- From the State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China and
| | - YouHua Zhang
- From the State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China and
| | - ShiHui Wang
- From the State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China and
| | - JunLei Wang
- From the State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China and
| | - Cui Liu
- From the State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China and
| | - JianFeng Chen
- From the State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China and
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9
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Cao B, Zhang Z, Grassinger J, Williams B, Heazlewood CK, Churches QI, James SA, Li S, Papayannopoulou T, Nilsson SK. Therapeutic targeting and rapid mobilization of endosteal HSC using a small molecule integrin antagonist. Nat Commun 2016; 7:11007. [PMID: 26975966 PMCID: PMC4796355 DOI: 10.1038/ncomms11007] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 02/10/2016] [Indexed: 12/24/2022] Open
Abstract
The inherent disadvantages of using granulocyte colony-stimulating factor (G-CSF) for hematopoietic stem cell (HSC) mobilization have driven efforts to identify alternate strategies based on single doses of small molecules. Here, we show targeting α9β1/α4β1 integrins with a single dose of a small molecule antagonist (BOP (N-(benzenesulfonyl)-L-prolyl-L-O-(1-pyrrolidinylcarbonyl)tyrosine)) rapidly mobilizes long-term multi-lineage reconstituting HSC. Synergistic engraftment augmentation is observed when BOP is co-administered with AMD3100. Impressively, HSC in equal volumes of peripheral blood (PB) mobilized with this combination effectively out-competes PB mobilized with G-CSF. The enhanced mobilization observed using BOP and AMD3100 is recapitulated in a humanized NODSCIDIL2Rγ−/− model, demonstrated by a significant increase in PB CD34+ cells. Using a related fluorescent analogue of BOP (R-BC154), we show that this class of antagonists preferentially bind human and mouse HSC and progenitors via endogenously primed/activated α9β1/α4β1 within the endosteal niche. These results support using dual α9β1/α4β1 inhibitors as effective, rapid and transient mobilization agents with promising clinical applications. Mobilizing haematopoietic stem cells to the peripheral blood has largely replaced bone marrow transplants as a strategy in the clinic. Here, Cao et al. report the use of an α9β1/α4β1 integrin antagonist to induce rapid mobilization of blood stem cells from the bone marrow in a humanized mouse model.
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Affiliation(s)
- Benjamin Cao
- Biomedical Manufacturing, CSIRO Manufacturing, Bag 10, Clayton South, Victoria 3169, Australia.,Australian Regenerative Medicine Institute, Monash University, Clayton, Victoria 3800, Australia
| | - Zhen Zhang
- Biomedical Manufacturing, CSIRO Manufacturing, Bag 10, Clayton South, Victoria 3169, Australia
| | - Jochen Grassinger
- University Hospital Regensberg, Department of Hematology and Oncology, Franz-Josef-Strauß-Allee 11, Regensburg 93053, Germany
| | - Brenda Williams
- Biomedical Manufacturing, CSIRO Manufacturing, Bag 10, Clayton South, Victoria 3169, Australia.,Australian Regenerative Medicine Institute, Monash University, Clayton, Victoria 3800, Australia
| | - Chad K Heazlewood
- Biomedical Manufacturing, CSIRO Manufacturing, Bag 10, Clayton South, Victoria 3169, Australia.,Australian Regenerative Medicine Institute, Monash University, Clayton, Victoria 3800, Australia
| | - Quentin I Churches
- Biomedical Manufacturing, CSIRO Manufacturing, Bag 10, Clayton South, Victoria 3169, Australia
| | - Simon A James
- Biomedical Manufacturing, CSIRO Manufacturing, Bag 10, Clayton South, Victoria 3169, Australia.,Australian Synchrotron, Clayton, Victoria 3168, Australia
| | - Songhui Li
- Biomedical Manufacturing, CSIRO Manufacturing, Bag 10, Clayton South, Victoria 3169, Australia.,Australian Regenerative Medicine Institute, Monash University, Clayton, Victoria 3800, Australia
| | - Thalia Papayannopoulou
- Department of Medicine/Hematology, University of Washington Seattle, 1705 NE Pacific, Box 357710, Seattle, Washington 98195-7710, USA
| | - Susan K Nilsson
- Biomedical Manufacturing, CSIRO Manufacturing, Bag 10, Clayton South, Victoria 3169, Australia.,Australian Regenerative Medicine Institute, Monash University, Clayton, Victoria 3800, Australia
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10
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Chigaev A. Does aberrant membrane transport contribute to poor outcome in adult acute myeloid leukemia? Front Pharmacol 2015; 6:134. [PMID: 26191006 PMCID: PMC4489100 DOI: 10.3389/fphar.2015.00134] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 06/15/2015] [Indexed: 12/31/2022] Open
Abstract
Acute myeloid leukemia in adults is a highly heterogeneous disease. Gene expression profiling performed using unsupervised algorithms can be used to distinguish specific groups of patients within a large patient cohort. The identified gene expression signatures can offer insights into underlying physiological mechanisms of disease pathogenesis. Here, the analysis of several related gene expression clusters associated with poor outcome, worst overall survival and highest rates of resistant disease and obtained from the patients at the time of diagnosis or from previously untreated individuals is presented. Surprisingly, these gene clusters appear to be enriched for genes corresponding to proteins involved in transport across membranes (transporters, carriers and channels). Several ideas describing the possible relationship of membrane transport activity and leukemic cell biology, including the "Warburg effect," the specific role of chloride ion transport, direct "import" of metabolic energy through uptake of creatine phosphate, and modification of the bone marrow niche microenvironment are discussed.
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Affiliation(s)
- Alexandre Chigaev
- Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, University of New Mexico Albuquerque, NM, USA
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11
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Chigaev A, Smagley Y, Sklar LA. Carbon monoxide down-regulates α4β1 integrin-specific ligand binding and cell adhesion: a possible mechanism for cell mobilization. BMC Immunol 2014; 15:52. [PMID: 25367365 PMCID: PMC4221689 DOI: 10.1186/s12865-014-0052-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 10/21/2014] [Indexed: 01/13/2023] Open
Abstract
Background Carbon monoxide (CO), a byproduct of heme degradation, is attracting growing attention from the scientific community. At physiological concentrations, CO plays a role as a signal messenger that regulates a number of physiological processes. CO releasing molecules are under evaluation in preclinical models for the management of inflammation, sepsis, ischemia/reperfusion injury, and organ transplantation. Because of our discovery that nitric oxide signaling actively down-regulates integrin affinity and cell adhesion, and the similarity between nitric oxide and CO-dependent signaling, we studied the effects of CO on integrin signaling and cell adhesion. Results We used a cell permeable CO releasing molecule (CORM-2) to elevate intracellular CO, and a fluorescent Very Late Antigen-4 (VLA-4, α4β1-integrin)-specific ligand to evaluate the integrin state in real-time on live cells. We show that the binding of the ligand can be rapidly down-modulated in resting cells and after inside-out activation through several Gαi-coupled receptors. Moreover, cell treatment with hemin, a natural source of CO, resulted in comparable VLA-4 ligand dissociation. Inhibition of VLA-4 ligand binding by CO had a dramatic effect on cell-cell interaction in a VLA-4/VCAM-1-dependent cell adhesion system. Conclusions We conclude that the CO signaling pathway can rapidly down-modulate binding of the VLA-4 -specific ligand. We propose that CO-regulated integrin deactivation provides a basis for modulation of immune cell adhesion as well as rapid cell mobilization, for example as shown for splenic monocytes in response to surgically induced ischemia of the myocardium.
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Affiliation(s)
- Alexandre Chigaev
- Department of Pathology and University of New Mexico Cancer Center, Albuquerque 87131, NM, USA.
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12
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Role of small GTPase protein Rac1 in cardiovascular diseases: development of new selective pharmacological inhibitors. J Cardiovasc Pharmacol 2014; 62:425-35. [PMID: 23921306 DOI: 10.1097/fjc.0b013e3182a18bcc] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
A pathway-based genome-wide association analysis has recently identified Rac1 as one of the biologically important gene in coronary heart diseases. The role of the small GTPase Rac1 in cardiac hypertrophy and atherosclerosis has also been documented in clinical studies with the HMG-CoA reductase inhibitors and in in vitro and in vivo settings using transgenic and knockout mice. Thus, Rac1 has emerged as a new pharmacological target for the treatment of cardiovascular diseases. The activation state of Rac1 depends on the release of guanosine diphosphate and the binding of guanosine triphosphate. This cycling is regulated by the guanine nucleotide exchange factors, as activators, and by the GTPase-activating proteins. Three categories of selective Rac1 inhibitors have been developed affecting different steps of this pathway: antagonists of Rac1-guanine nucleotide exchange factor interaction, allosteric inhibitors of nucleotide binding to Rac1, and antagonists of Rac1-mediated NADPH oxidase activity. These chemical compounds have shown to selectively inhibit Rac1 activation in cultured cell lines without affecting the homologous proteins RhoA and Cdc42. Moreover, pioneer studies have been conducted with Rac1 inhibitors in in vivo experimental models of cardiovascular diseases with encouraging results. The present review summarizes the current knowledge of the role of Rac1 in cardiovascular diseases and the pharmacological approaches that have been developed to selectively inhibit its function.
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Systems approach to phagocyte production and activation: neutrophils and monocytes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 844:99-113. [PMID: 25480639 DOI: 10.1007/978-1-4939-2095-2_6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Granulocyte differentiation and immune response function is a dynamic process governed by a highly coordinated transcriptional program that regulates cellular fate and function, often in a context-dependent manner. Advances in high-throughput technologies and bioinformatics have allowed us to better understand complex biological processes at the genomic and proteomic levels. Components of the environmental milieu, along with the molecular mechanisms that drive the development, activation, and regulation of granulocytes, have since been elucidated. In this chapter, we present the intricate network in which these elements come together and influence one another. In particular, we describe the critical roles of transcription factors like PU.1, CCAAT/enhancer-binding protein (C/EBPα; alpha), C/EBPε (epsilon), and growth factor independent-1 (Gfi-1). We also review granulocyte colony-stimulating factor (G-CSF) receptor-induced signal transduction pathways, their influence on proliferation and differentiation, and the cooperativity of cytokines and chemokines in this process.
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14
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Abstract
Natalizumab antibody to α4-integrins is used in therapy of multiple sclerosis and Crohn's disease. A crystal structure of the Fab bound to an α4 integrin β-propeller and thigh domain fragment shows that natalizumab recognizes human-mouse differences on the circumference of the β-propeller domain. The epitope is adjacent to but outside of a ligand-binding groove formed at the interface with the β-subunit βI domain and shows no difference in structure when bound to Fab. Competition between Fab and the ligand vascular cell adhesion molecule (VCAM) for binding to cell surface α4β1 shows noncompetitive antagonism. In agreement, VCAM docking models suggest that binding of domain 1 of VCAM to α4-integrins is unimpeded by the Fab, and that bound Fab requires a change in orientation between domains 1 and 2 of VCAM for binding to α4β1. Mapping of species-specific differences onto α4β1 and α4β7 shows that their ligand-binding sites are highly conserved. Skewing away from these conserved regions of the epitopes recognized by current therapeutic function-blocking antibodies has resulted in previously unanticipated mechanisms of action.
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Affiliation(s)
- Yamei Yu
- From the Program in Cellular and Molecular Medicine, Children's Hospital Boston and Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115
| | - Thomas Schürpf
- From the Program in Cellular and Molecular Medicine, Children's Hospital Boston and Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115
| | - Timothy A Springer
- From the Program in Cellular and Molecular Medicine, Children's Hospital Boston and Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115.
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15
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Reder-Christ K, Schmitz P, Bota M, Gerber U, Falkenstein-Paul H, Fuss C, Enachescu M, Bendas G. A dry membrane protection technique to allow surface acoustic wave biosensor measurements of biological model membrane approaches. SENSORS (BASEL, SWITZERLAND) 2013; 13:12392-405. [PMID: 24064603 PMCID: PMC3821348 DOI: 10.3390/s130912392] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 09/03/2013] [Accepted: 09/06/2013] [Indexed: 12/13/2022]
Abstract
Model membrane approaches have attracted much attention in biomedical sciences to investigate and simulate biological processes. The application of model membrane systems for biosensor measurements is partly restricted by the fact that the integrity of membranes critically depends on the maintenance of an aqueous surrounding, while various biosensors require a preconditioning of dry sensors. This is for example true for the well-established surface acoustic wave (SAW) biosensor SAM®5 blue. Here, a simple drying procedure of sensor-supported model membranes is introduced using the protective disaccharide trehalose. Highly reproducible model membranes were prepared by the Langmuir-Blodgett technique, transferred to SAW sensors and supplemented with a trehalose solution. Membrane rehydration after dry incorporation into the SAW device becomes immediately evident by phase changes. Reconstituted model membranes maintain their full functionality, as indicated by biotin/avidin binding experiments. Atomic force microscopy confirmed the morphological invariability of dried and rehydrated membranes. Approximating to more physiological recognition phenomena, the site-directed immobilization of the integrin VLA-4 into the reconstituted model membrane and subsequent VCAM-1 ligand binding with nanomolar affinity were illustrated. This simple drying procedure is a novel way to combine the model membrane generation by Langmuir-Blodgett technique with SAW biosensor measurements, which extends the applicability of SAM®5 blue in biomedical sciences.
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Affiliation(s)
- Katrin Reder-Christ
- Pharmaceutical Chemistry, Rheinische Friedrich-Wilhelms-Universität Bonn, An der Immenburg 4, Bonn D-53121, Germany; E-Mails: (P.S.); (U.G.); (H.F.-P.); (C.F.); (G.B.)
| | - Patrick Schmitz
- Pharmaceutical Chemistry, Rheinische Friedrich-Wilhelms-Universität Bonn, An der Immenburg 4, Bonn D-53121, Germany; E-Mails: (P.S.); (U.G.); (H.F.-P.); (C.F.); (G.B.)
| | - Marian Bota
- Center for Surface Science and Nanotechnology, University Politehnica of Bucharest, 313 Splaiul Independentei, Bucharest, RO-060042, Romania; E-Mails: (M.B.); (M.E.)
| | - Ursula Gerber
- Pharmaceutical Chemistry, Rheinische Friedrich-Wilhelms-Universität Bonn, An der Immenburg 4, Bonn D-53121, Germany; E-Mails: (P.S.); (U.G.); (H.F.-P.); (C.F.); (G.B.)
| | - Hildegard Falkenstein-Paul
- Pharmaceutical Chemistry, Rheinische Friedrich-Wilhelms-Universität Bonn, An der Immenburg 4, Bonn D-53121, Germany; E-Mails: (P.S.); (U.G.); (H.F.-P.); (C.F.); (G.B.)
| | - Christian Fuss
- Pharmaceutical Chemistry, Rheinische Friedrich-Wilhelms-Universität Bonn, An der Immenburg 4, Bonn D-53121, Germany; E-Mails: (P.S.); (U.G.); (H.F.-P.); (C.F.); (G.B.)
| | - Marius Enachescu
- Center for Surface Science and Nanotechnology, University Politehnica of Bucharest, 313 Splaiul Independentei, Bucharest, RO-060042, Romania; E-Mails: (M.B.); (M.E.)
- Academy of Romanian Scientists, 54 Splaiul Independentei, Bucharest, RO-050094, Romania
| | - Gerd Bendas
- Pharmaceutical Chemistry, Rheinische Friedrich-Wilhelms-Universität Bonn, An der Immenburg 4, Bonn D-53121, Germany; E-Mails: (P.S.); (U.G.); (H.F.-P.); (C.F.); (G.B.)
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16
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Chigaev A, Sklar LA. Aspects of VLA-4 and LFA-1 regulation that may contribute to rolling and firm adhesion. Front Immunol 2012; 3:242. [PMID: 22876249 PMCID: PMC3410440 DOI: 10.3389/fimmu.2012.00242] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Accepted: 07/18/2012] [Indexed: 01/21/2023] Open
Abstract
Very Late Antigen-4 (CD49d/CD29, alpha4 beta1) and Lymphocyte Function-associated Antigen-1 (CD11a/CD18, alphaL beta2) integrins are representatives of a large family of adhesion receptors widely expressed on immune cells. They participate in cell recruitment to sites of inflammation, as well as multiple immune cell interactions. A unique feature of integrins is that integrin-dependent cell adhesion can be rapidly and reversibly modulated in response to cell signaling, because of a series of conformational changes within the molecule, which include changes in the affinity of the ligand binding pocket, molecular extension (unbending) and others. Here, we provide a concise comparative analysis of the conformational regulation of the two integrins with specific attention to the physiological differences between these molecules. We focus on recent data obtained using a novel technology, based on small fluorescent ligand-mimicking probes for the detection of integrin conformation in real-time on live cells at natural receptor abundance.
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Affiliation(s)
- Alexandre Chigaev
- Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, Albuquerque NM, USA
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17
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Rettig MP, Ansstas G, DiPersio JF. Mobilization of hematopoietic stem and progenitor cells using inhibitors of CXCR4 and VLA-4. Leukemia 2012; 26:34-53. [PMID: 21886173 PMCID: PMC3514440 DOI: 10.1038/leu.2011.197] [Citation(s) in RCA: 138] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Revised: 03/31/2011] [Accepted: 05/23/2011] [Indexed: 12/29/2022]
Abstract
Successful hematopoietic stem cell transplant requires the infusion of a sufficient number of hematopoietic stem/progenitor cells (HSPCs) that are capable of homing to the bone marrow cavity and regenerating durable trilineage hematopoiesis in a timely manner. Stem cells harvested from peripheral blood are the most commonly used graft source in HSCT. Although granulocyte colony-stimulating factor (G-CSF) is the most frequently used agent for stem cell mobilization, the use of G-CSF alone results in suboptimal stem cell yields in a significant proportion of patients. Both the chemokine receptor CXCR4 and the integrin α(4)β(1) (very late antigen 4 (VLA-4)) have important roles in the homing and retention of HSPCs within the bone marrow microenvironment. Preclinical and/or clinical studies have shown that targeted disruption of the interaction of CXCR4 or VLA-4 with their ligands results in the rapid and reversible mobilization of hematopoietic stem cells into the peripheral circulation and is synergistic when combined with G-CSF. In this review, we discuss the development of small-molecule CXCR4 and VLA-4 inhibitors and how they may improve the utility and convenience of peripheral blood stem cell transplantation.
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Affiliation(s)
- M P Rettig
- Division of Oncology, Siteman Cancer Center, Washington University School of Medicine, St Louis, MO 63110, USA
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18
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Martínez-Viñambres E, García-Trujillo JA, Rodríguez-Martín E, Villar LM, Coll J, Roldán E. CD29 expressed on plasma cells is activated by divalent cations and soluble CD106 contained in the bone marrow plasma: refractory activation is associated with enhanced proliferation and exit of clonal plasma cells to circulation in multiple myeloma patients. Leukemia 2011; 26:1098-105. [DOI: 10.1038/leu.2011.335] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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19
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Chigaev A, Smagley Y, Sklar LA. Nitric oxide/cGMP pathway signaling actively down-regulates α4β1-integrin affinity: an unexpected mechanism for inducing cell de-adhesion. BMC Immunol 2011; 12:28. [PMID: 21586157 PMCID: PMC3125286 DOI: 10.1186/1471-2172-12-28] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Accepted: 05/17/2011] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Integrin activation in response to inside-out signaling serves as the basis for rapid leukocyte arrest on endothelium, migration, and mobilization of immune cells. Integrin-dependent adhesion is controlled by the conformational state of the molecule, which is regulated by seven-transmembrane Guanine nucleotide binding Protein-Coupled Receptors (GPCRs). α4β1-integrin (CD49d/CD29, Very Late Antigen-4, VLA-4) is expressed on leukocytes, hematopoietic progenitors, stem cells, hematopoietic cancer cells, and others. VLA-4 conformation is rapidly up-regulated by inside-out signaling through Gαi-coupled GPCRs and down-regulated by Gαs-coupled GPCRs. However, other signaling pathways, which include nitric oxide-dependent signaling, have been implicated in the regulation of cell adhesion. The goal of the current report was to study the effect of nitric oxide/cGMP signaling pathway on VLA-4 conformational regulation. RESULTS Using fluorescent ligand binding to evaluate the integrin activation state on live cells in real-time, we show that several small molecules, which specifically modulate nitric oxide/cGMP signaling pathway, as well as a cell permeable cGMP analog, can rapidly down-modulate binding of a VLA-4 specific ligand on cells pre-activated through three Gαi-coupled receptors: wild type CXCR4, CXCR2 (IL-8RB), and a non-desensitizing mutant of formyl peptide receptor (FPR ΔST). Upon signaling, we detected rapid changes in the ligand dissociation rate. The dissociation rate after inside-out integrin de-activation was similar to the rate for resting cells. In a VLA-4/VCAM-1-specific myeloid cell adhesion system, inhibition of the VLA-4 affinity change by nitric oxide had a statistically significant effect on real-time cell aggregation. CONCLUSIONS We conclude that nitric oxide/cGMP signaling pathway can rapidly down-modulate the affinity state of the VLA-4 binding pocket, especially under the condition of sustained Gαi-coupled GPCR signaling, generated by a non-desensitizing receptor mutant. This suggests a fundamental role of this pathway in de-activation of integrin-dependent cell adhesion.
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Affiliation(s)
- Alexandre Chigaev
- Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA.
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20
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Chigaev A, Smagley Y, Zhang Y, Waller A, Haynes MK, Amit O, Wang W, Larson RS, Sklar LA. Real-time analysis of the inside-out regulation of lymphocyte function-associated antigen-1 revealed similarities to and differences from very late antigen-4. J Biol Chem 2011; 286:20375-86. [PMID: 21515675 PMCID: PMC3121518 DOI: 10.1074/jbc.m110.206185] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Ten years ago, we introduced a fluorescent probe that shed light on the inside-out regulation of one of the major leukocyte integrins, very late antigen-4 (VLA-4, CD49d/CD29). Here we describe the regulation of another leukocyte integrin, lymphocyte function-associated antigen-1 (LFA-1, CD11a/CD18) using a novel small fluorescent probe in real time on live cells. We found that multiple signaling mechanisms regulate LFA-1 conformation in a manner analogous to VLA-4. LFA-1 can be rapidly activated by Gαi-coupled G protein-coupled receptors (GPCRs) and deactivated by Gαs-coupled GPCRs. The effects of Gαs-coupled GPCR agonists can be reversed in real time by receptor-specific antagonists. The specificity of the fluorescent probe binding has been assessed in a competition assay using the natural LFA-1 ligand ICAM-1 and the LFA-1-specific α I allosteric antagonist BIRT0377. Similar to VLA-4 integrin, modulation of the ligand dissociation rate can be observed for different LFA-1 affinity states. However, we also found a striking difference in the binding of the small fluorescent ligand. In the absence of inside-out activation ligand, binding to LFA-1 is extremely slow, at least 10 times slower than expected for diffusion-limited binding. This implies that an additional structural mechanism prevents ligand binding to inactive LFA-1. We propose that such a mechanism explains the inability of LFA-1 to support cell rolling, where the absence of its rapid engagement by a counterstructure in the inactive state leads to a requirement for a selectin-mediated rolling step.
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Affiliation(s)
- Alexandre Chigaev
- Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131, USA.
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21
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Chigaev A, Wu Y, Williams DB, Smagley Y, Sklar LA. Discovery of very late antigen-4 (VLA-4, alpha4beta1 integrin) allosteric antagonists. J Biol Chem 2011; 286:5455-63. [PMID: 21131351 PMCID: PMC3037658 DOI: 10.1074/jbc.m110.162636] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2010] [Revised: 11/19/2010] [Indexed: 11/06/2022] Open
Abstract
Integrins are cell adhesion receptors that mediate cell-to-cell, or cell-to-extracellular matrix adhesion. They represent an attractive target for treatment of multiple diseases. Two classes of small molecule integrin inhibitors have been developed. Competitive antagonists bind directly to the integrin ligand binding pocket and thus disrupt the ligand-receptor interaction. Allosteric antagonists have been developed primarily for α(L)β(2)- integrin (LFA-1, lymphocyte function-associated antigen-1). Here we present the results of screening the Prestwick Chemical Library using a recently developed assay for the detection of α(4)β(1)-integrin allosteric antagonists. Secondary assays confirmed that the compounds identified: 1) do not behave like competitive (direct) antagonists; 2) decrease ligand binding affinity for VLA-4 ∼2 orders of magnitude; 3) exhibit antagonistic properties at low temperature. In a cell based adhesion assay in vitro, the compounds rapidly disrupted cellular aggregates. In accord with reports that VLA-4 antagonists in vivo induce mobilization of hematopoietic progenitors into the peripheral blood, we found that administration of one of the compounds significantly increased the number of colony-forming units in mice. This effect was comparable to AMD3100, a well known progenitor mobilizing agent. Because all the identified compounds are structurally related, previously used, or currently marketed drugs, this result opens a range of therapeutic possibilities for VLA-4-related pathologies.
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Affiliation(s)
- Alexandre Chigaev
- From the Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131
| | - Yang Wu
- From the Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131
| | - D. Bart Williams
- From the Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131
| | - Yelena Smagley
- From the Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131
| | - Larry A. Sklar
- From the Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131
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22
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Zwartz GJ, Chigaev A, Foutz TD, Edwards B, Sklar LA. A miniature Couette to generate shear for flow cytometry: studying real-time modulation of intracellular calcium in monocytic cells. Cytometry A 2011; 79:233-40. [PMID: 22045643 DOI: 10.1002/cyto.a.21027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2010] [Revised: 12/17/2010] [Accepted: 01/03/2011] [Indexed: 11/07/2022]
Abstract
Extracellular hydrodynamic forces may be transmitted to the interior of cells through the alteration of integrin conformation and affinity. Integrin activation regulates leukocyte recruitment, cell activation, and transmigration. The cellular and molecular mechanisms for integrin activation are not precisely known, although intracellular calcium signaling is involved. Flow cytometry offers a versatile way to study intracellular calcium signaling in real-time. We report a novel method to generate defined shear by using a miniature Couette. Testing involved measuring shear-induced intracellular calcium signals of human monoblastoid U937 cells in suspension. The Couette was connected externally to a flow cytometer and pressurized at 6 PSI (4.1 N/m(2) ). Cells were subjected to a well-defined shear between 0 and 1,000 s(-1) and delivered continuously within 10 s to a FACScan at 1 μl/s. Intracellular calcium levels and the percentage of cells activated increased as shear increased in duration and intensity.
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Affiliation(s)
- Gordon J Zwartz
- Department of Physics, University of New Mexico Health Science Center, Albuquerque, NM 87131, USA.
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23
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Wang L, Shirure VS, Burdick MM, Wu S. UVB-irradiation regulates VLA-4-mediated melanoma cell adhesion to endothelial VCAM-1 under flow conditions. Mol Carcinog 2011; 50:58-65. [PMID: 21061269 DOI: 10.1002/mc.20696] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The major aspect contributing to the mortality of melanoma is its ability to spread, or metastasize. Ultraviolet B light (UVB) is considered an indirect cause of melanoma formation. However, little is known about the potential effects of UVB to melanoma metastasis. Integrins, a large family of cell adhesion molecules (CAMs) expressed on the melanoma cell surface, are important for cell signaling, growth, and migration during metastasis. Most critically, tumor cell tissue invasion is dependent on the initial interaction of tumor cells with vascular endothelium at the target organ, and there is increasing evidence for a prominent role of melanoma very late antigen-4 (VLA-4) integrin binding to its endothelial ligand vascular cell adhesion molecule-1 (VCAM-1) in this process. This research focuses on the quantitative modulation of VLA-4 integrin expression and function on melanoma cells after UVB irradiation. The present data show that at 3, 12, and 18 h post-UVB irradiation, VLA-4 expression was unchanged relative to untreated cells, but adhesion to VCAM-1 decreased significantly. Immunofluorescence studies implied that the spatial organization of VLA-4 on the melanoma cell surface contributed to the changes in avidity for VCAM-1 upon UVB irradiation. With increased understanding of the molecular mechanisms underlying melanoma-endothelial interactions upon UVB irradiation, clinical advances for melanoma may be developed.
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Affiliation(s)
- Lei Wang
- Edison Biotechnology Institute, Ohio University, Athens, Ohio, USA
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25
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Abstract
Interaction of the integrin receptors with ligands determines the molecular basis of integrin-dependent cell adhesion. Integrin ligands are typically large proteins with relatively low binding affinities. This makes direct ligand-binding kinetic measurements somewhat difficult. Here we examine several real-time methods, aimed to overcome these experimental limitations and to distinguish the regulation of integrin conformation and affinity. This chapter includes: the use of a small ligand-mimetic probe for studies of inside-out regulation of integrin affinity and unbending, real-time cell aggregation and disaggregation kinetics to probe integrin conformational states and the number of integrin-ligand bonds, as well as the real-time monitoring of ligand-induced epitopes under signaling through G-protein-coupled receptors, and others. Experimental data obtained using these novel methods are summarized in terms of the current model of integrin activation.
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Affiliation(s)
- Alexandre Chigaev
- Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, NM, USA.
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26
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Régent M, Planus E, Bouin AP, Bouvard D, Brunner M, Faurobert E, Millon-Frémillon A, Block MR, Albiges-Rizo C. Specificities of β1 integrin signaling in the control of cell adhesion and adhesive strength. Eur J Cell Biol 2010; 90:261-9. [PMID: 20971526 DOI: 10.1016/j.ejcb.2010.09.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 09/01/2010] [Accepted: 09/02/2010] [Indexed: 11/26/2022] Open
Abstract
Cells exert actomyosin contractility and cytoskeleton-dependent force in response to matrix stiffness cues. Cells dynamically adapt to force by modifying their behavior and remodeling their microenvironment. This adaptation is favored by integrin activation switch and their ability to modulate their clustering and the assembly of an intracellular hub in response to force. Indeed integrins are mechanoreceptors and mediate mechanotransduction by transferring forces to specific adhesion proteins into focal adhesions which are sensitive to tension and activate intracellular signals. α(5)β(1) integrin is considered of major importance for the formation of an elaborate meshwork of fibronectin fibrils and for the extracellular matrix deposition and remodeling. Here we summarize recent progress in the study of mechanisms regulating the activation cycle of β(1) integrin and the specificity of α(5)β(1) integrin in mechanotransduction.
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Affiliation(s)
- Myriam Régent
- INSERM U823 Institut Albert Bonniot, Université Joseph Fourier, France
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27
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Murata A, Okuyama K, Sakano S, Kajiki M, Hirata T, Yagita H, Zúñiga-Pflücker JC, Miyake K, Akashi-Takamura S, Moriwaki S, Niida S, Yoshino M, Hayashi SI. A Notch ligand, Delta-like 1 functions as an adhesion molecule for mast cells. THE JOURNAL OF IMMUNOLOGY 2010; 185:3905-12. [PMID: 20810995 DOI: 10.4049/jimmunol.1000195] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Mast cells (MCs) accumulate in chronic inflammatory sites; however, it is not clear which adhesion molecules are involved in this process. Recently, the expression of Notch ligands was reported to be upregulated in inflammatory sites. Although Notch receptors are known as signaling molecules that can activate integrins, their contributions to the adhesion of MCs have not been studied. In this study, we demonstrated that mouse MCs efficiently adhered to stromal cells forced to express a Notch ligand, Delta-like 1 (Dll1). Surprisingly, the adhesion was a consequence of direct cell-cell interaction between MCs and Dll1-expressing stromal cells rather than activation of downstream effectors of Notch receptor(s)-Dll1. The adhesion of MCs to Dll1-expressing stromal cells remained even when the cell metabolism was arrested. The recognition was blocked only by inhibition of Notch receptor(s)-Dll1 interaction by addition of soluble DLL1, or mAbs against Dll1 or Notch2. Taken together, these results indicate that Notch receptor(s) and Dll1 directly promote the adhesion of MCs to stromal cells by acting as adhesion molecules. This appreciation that Notch receptor-ligand interactions have an adhesion function will provide an important clue to molecular basis of accumulation of MCs to inflammatory sites.
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Affiliation(s)
- Akihiko Murata
- Division of Immunology, Department of Molecular and Cellular Biology, School of Life Science, Faculty of Medicine, Tottori University, Yonago, Japan.
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28
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Alvarez JI, Cayrol R, Prat A. Disruption of central nervous system barriers in multiple sclerosis. Biochim Biophys Acta Mol Basis Dis 2010; 1812:252-64. [PMID: 20619340 DOI: 10.1016/j.bbadis.2010.06.017] [Citation(s) in RCA: 231] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Revised: 06/10/2010] [Accepted: 06/28/2010] [Indexed: 12/30/2022]
Abstract
The delicate microenvironment of the central nervous system (CNS) is protected by the blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (BCB). These barriers function in distinct CNS compartments and their anatomical basis lay on the junctional proteins present in endothelial cells for the BBB and in the choroidal epithelium for the BCB. During neuroinflammatory conditions like multiple sclerosis (MS) and its murine model experimental autoimmune encephalomyelitis (EAE), activation or damage of the various cellular components of these barriers facilitate leukocyte infiltration leading to oligodendrocyte death, axonal damage, demyelination and lesion development. This manuscript will review in detail the features of these barriers under physiological and pathological conditions, particularly when focal immune activation promotes the loss of the BBB and BCB phenotype, the upregulation of cell adhesion molecules (CAMs) and the recruitment of immune cells.
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Affiliation(s)
- Jorge Ivan Alvarez
- Neuroimmunology Research Laboratory, Center of Excellence in Neuromics, CHUM-Notre-Dame Hospital, Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
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Imai Y, Shimaoka M, Kurokawa M. Essential roles of VLA-4 in the hematopoietic system. Int J Hematol 2010; 91:569-75. [PMID: 20352381 DOI: 10.1007/s12185-010-0555-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2010] [Revised: 03/05/2010] [Accepted: 03/09/2010] [Indexed: 12/01/2022]
Abstract
Integrins are one of the major families of adhesion molecules and make various kinds of biological effects by mediating cell-cell and cell-matrix interactions. Among integrins, VLA-4 is expressed on many types of hematopoietic cells including stem/progenitor cells and it is considered as a critical regulator of adult hematopoiesis. Recent studies revealed that VLA-4 is not necessarily required for the development or maintenance of adult hematopoietic cells. On the other hand, it was proved that VLA-4 is essential for homeostasis of distribution of hematopoietic stem/progenitor cells (HSPCs) and mature lymphocytes in the body. The dynamic regulation of VLA-4 function is mediated by its conformational change, which is strictly linked to the interaction between alpha and beta cytoplasmic domains. The study using knockin mice showed that GFFKR sequence, a well-preserved motif in the alpha cytoplasmic domain of VLA-4, is critical for binding of alpha and beta cytoplasmic domains as well as regulation of hematopoietic cell distribution. Small molecules targeting this cytoplasmic interaction or ligand-VLA-4 interaction may become good candidates of new drugs for mobilization of hematopoietic stem cells. Several studies have suggested the impact of VLA-4 on chemotherapy sensitivity and prognosis in hematological malignancies, which awaits further investigations.
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Affiliation(s)
- Yoichi Imai
- Department of Hematology and Oncology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
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Lomakina EB, Waugh RE. Adhesion between human neutrophils and immobilized endothelial ligand vascular cell adhesion molecule 1: divalent ion effects. Biophys J 2010; 96:276-84. [PMID: 19134480 DOI: 10.1016/j.bpj.2008.10.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2008] [Accepted: 10/09/2008] [Indexed: 10/21/2022] Open
Abstract
Integrin-mediated adhesion of circulating neutrophils to endothelium during inflammation involves multiple adhesion molecules on both neutrophils and endothelium. Most studies of neutrophil adhesion have focused on adhesion to ICAM-1 (mediated by beta(2) integrins), but interaction with the endothelial ligand vascular cell adhesion molecule 1 (VCAM-1) may also play a role in neutrophil adhesion to activated endothelium. In this study we demonstrate significant adhesion between neutrophils and VCAM-1 mediated by beta(1) integrins, principally via alpha(4)beta(1) (VLA-4). We characterize the dynamics of adhesion in terms of rate constants for a two-step bond formation process, the first involving juxtaposition of active molecules with substrate and the second involving bond formation. The results indicate that the first step is rate limiting for VLA-4-VCAM-1 interactions. Changing divalent cation composition affects these coefficients, implicating molecular conformational changes as a key step in the process.
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Affiliation(s)
- Elena B Lomakina
- Department of Pharmacology and Physiology, University of Rochester, Medical Center, Rochester, New York, USA
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31
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Model MA, Reese JL, Fraizer GC. Measurement of wheat germ agglutinin binding with a fluorescence microscope. Cytometry A 2010; 75:874-81. [PMID: 19722258 DOI: 10.1002/cyto.a.20787] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Signal intensity in fluorescence microscopy is often measured relative to arbitrary standards. We propose a calibration method based on a solution of the same fluorophore, whose binding to cells needs to be quantified. The method utilizes the low sensitivity of intensity to the object distance in wide-field imaging of uniform materials. Liquid layers of slowly varying depth were prepared by immersing a spherical lens into a drop of a fluorophore placed on a slide. Flatfield-corrected images of the contact and surrounding areas showed linear dependence of the gray level on the depth of fluorescent liquid. This allowed conversion of the measured intensity into the number of molecules per unit area. The method was applied to different cell types stained by WGA-Alexa 488 and WGA-TRITC. Consistent results were obtained by comparing microscopy with flow cytometry, comparing imaging through different objectives and comparing different WGA conjugates. Reproducibility of calibration was within 97% when low magnification was used. Fluorescence of free and bound WGA was found to be different, however, and therefore precise measurement of the number of cell-bound molecules was problematic in this particular system. We conclude that the method achieves reliable measurement of cellular staining in the units of soluble fluorophore. For probes whose fluorescent properties are unaffected by binding, quantification of staining in true molecular units should be possible.
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Affiliation(s)
- Michael A Model
- Department of Biological Sciences, Kent State University, Kent, Ohio 44242, USA.
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32
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Phylogenetic analysis and homology modelling of Paracentrotus lividus nectin. Mol Divers 2009; 14:653-65. [DOI: 10.1007/s11030-009-9203-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2009] [Accepted: 10/20/2009] [Indexed: 01/21/2023]
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Njus BH, Chigaev A, Waller A, Wlodek D, Ostopovici-Halip L, Ursu O, Wang W, Oprea TI, Bologa CG, Sklar LA. Conformational mAb as a tool for integrin ligand discovery. Assay Drug Dev Technol 2009; 7:507-15. [PMID: 19754304 PMCID: PMC3096548 DOI: 10.1089/adt.2009.0203] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
alpha(4)beta(1)-Integrin (very late antigen-4 (VLA-4)) mediates cell adhesion to cell surface ligands (VCAM-1). Binding of VLA-4 to VCAM-1 initiates rolling and firm adhesion of leukocytes to vascular endothelium followed by the extravasation into the tissue. VLA-4-dependent adhesion plays a key role in controlling leukocyte adhesive events. Small molecules that bind to the integrin ligand-binding site and block its interaction with natural ligands represent promising candidates for treatment of several diseases. Following a flow cytometric screen for small molecule discovery, we took advantage of a conformationally sensitive anti-beta(1)-integrin antibody (HUTS-21) and a small LDV-containing ligand (LDV-FITC) with known affinity to study binding affinities of several known and recently discovered integrin ligands. We found that binding of the LDV-containing small molecule induced exposure of HUTS-21 epitope and that the EC(50) for antibody binding was equal to previously reported K(d) for fluorescent LDV (LDV-FITC). Thus, binding of HUTS-21 can be used to report ligand-binding site occupancy. We studied binding of two known integrin ligands (YLDV and TR14035), as well as of two novel compounds. EC(50) values for HUTS-21 binding showed good correlation with K(i)s determined in the competition assay with LDV-FITC for all ligands. A docking model suggests a common mode of binding for the small molecule VLA-4 ligands. This novel approach described here can be used to determine ligand-binding affinities for unlabeled integrin ligands, and can be adapted to a high-throughput screening format for identification of unknown integrin ligands.
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Affiliation(s)
- Ben H. Njus
- Department of Chemistry, University of New Mexico Health Sciences Center, Albuquerque, New Mexico.
| | - Alexandre Chigaev
- Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, New Mexico.
| | - Anna Waller
- Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, New Mexico.
| | - Danuta Wlodek
- Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, New Mexico.
| | - Liliana Ostopovici-Halip
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico.
- Romanian Academy—Institute of Chemistry, Timisoara, Romania.
| | - Oleg Ursu
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico.
| | - Wei Wang
- Department of Chemistry, University of New Mexico Health Sciences Center, Albuquerque, New Mexico.
| | - Tudor I. Oprea
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico.
| | - Cristian G. Bologa
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico.
| | - Larry A. Sklar
- Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, New Mexico.
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Chigaev A, Waller A, Amit O, Halip L, Bologa CG, Sklar LA. Real-time analysis of conformation-sensitive antibody binding provides new insights into integrin conformational regulation. J Biol Chem 2009; 284:14337-46. [PMID: 19251697 PMCID: PMC2682882 DOI: 10.1074/jbc.m901178200] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Integrins are heterodimeric adhesion receptors that regulate immune cell
adhesion. Integrin-dependent adhesion is controlled by multiple conformational
states that include states with different affinity to the ligand, states with
various degrees of molecule unbending, and others. Affinity change and
molecule unbending play major roles in the regulation of cell adhesion. The
relationship between different conformational states of the integrin is
unclear. Here we have used conformationally sensitive antibodies and a small
LDV-containing ligand to study the role of the inside-out signaling through
formyl peptide receptor and CXCR4 in the regulation of
α4β1 integrin conformation. We found that in
the absence of ligand, activation by formyl peptide or SDF-1 did not result in
a significant exposure of HUTS-21 epitope. Occupancy of the ligand binding
pocket without cell activation was sufficient to induce epitope exposure.
EC50 for HUTS-21 binding in the presence of LDV was identical to a
previously reported ligand equilibrium dissociation constant at rest and after
activation. Furthermore, the rate of HUTS-21 binding was also related to the
VLA-4 activation state even at saturating ligand concentration. We propose
that the unbending of the integrin molecule after guanine nucleotide-binding
protein-coupled receptor-induced signaling accounts for the enhanced rate of
HUTS-21 binding. Taken together, current results support the existence of
multiple conformational states independently regulated by both inside-out
signaling and ligand binding. Our data suggest that VLA-4 integrin hybrid
domain movement does not depend on the affinity state of the ligand binding
pocket.
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Affiliation(s)
- Alexandre Chigaev
- Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131, USA.
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Petty JM, Lenox CC, Weiss DJ, Poynter ME, Suratt BT. Crosstalk between CXCR4/stromal derived factor-1 and VLA-4/VCAM-1 pathways regulates neutrophil retention in the bone marrow. THE JOURNAL OF IMMUNOLOGY 2009; 182:604-12. [PMID: 19109194 DOI: 10.4049/jimmunol.182.1.604] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Neutrophil retention in and release from the bone marrow is a critical process that remains incompletely understood. Previous work has implicated the CXCR4/stromal derived factor-1 (SDF-1) chemokine axis in the marrow retention of neutrophils, yet the adhesion pathways responsible for this retention are unknown. Because alpha(4)beta(1) integrin (VLA-4) and its ligand VCAM-1 play a central role in the interactions of hematopoietic stem cells, lymphocytes, and developing neutrophils in the marrow, we investigated whether this integrin might be involved in marrow neutrophil retention and release. In this study, we show that VLA-4 is expressed on murine marrow neutrophils and decreases with maturation, whereas blockade of this integrin leads to the release of marrow neutrophils. Marrow neutrophils adhere via VLA-4 to VCAM-1, which is expressed on marrow endothelium and stroma, and inhibition of VCAM-1 causes release of marrow neutrophils. Furthermore, SDF-1 (CXCL12) signaling through neutrophil CXCR4 augments VLA-4 adhesion to VCAM-1 in vitro, an effect that is blocked by preincubation with pertussis toxin. In vivo blockade of both CXCR4 and alpha(4) causes synergistic release of marrow neutrophils, showing that cross-talk between CXCR4 and VLA-4 modulates marrow retention of these cells. Taken together, these results indicate that the VLA-4/VCAM adhesion pathway is critical in the retention and maturation-controlled release of neutrophils from the marrow, while providing an important link between the CXCR4/SDF-1 signaling axis and the adhesion events that govern this process.
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Affiliation(s)
- Joseph M Petty
- Department of Medicine, University of Vermont College of Medicine, Burlington, VT 05405, USA
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Craig DH, Gayer CP, Schaubert KL, Wei Y, Li J, Laouar Y, Basson MD. Increased extracellular pressure enhances cancer cell integrin-binding affinity through phosphorylation of beta1-integrin at threonine 788/789. Am J Physiol Cell Physiol 2008; 296:C193-204. [PMID: 19005162 DOI: 10.1152/ajpcell.00355.2008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Increased extracellular pressure stimulates beta1-integrin-dependent cancer cell adhesion. We asked whether pressure-induced adhesion is mediated by changes in beta1-integrin binding affinity or avidity and whether these changes are phosphorylation dependent. We evaluated integrin affinity and clustering in human SW620 colon cancer cells by measuring differences in binding between soluble Arg-Gly-Asp (RGD)-Fc ligands and RGD-Fc-F(ab')2 multimeric complexes under ambient and 15-mmHg increased pressures. Phosphorylation of beta1-integrin S785 and T788/9 residues in SW620 and primary malignant colonocytes was assessed in parallel. We further used GD25-beta1-integrin-null murine fibroblasts stably transfected with either wild-type beta1A-integrin, S785A, TT788/9AA, or T788D mutants to investigate the role of beta1-integrin site-specific phosphorylation. SW620 binding of RGD-Fc-F(ab')2 multimeric complexes, but not soluble RGD-Fc ligands, was sensitive to integrin clustering. RGD-Fc ligand binding was significantly increased under elevated pressure, suggesting that pressure modulates beta1-integrin affinity. Pressure stimulated both beta1-integrin S785 and T788/9 phosphorylation. GD25-beta1A-integrin wild-type and S785A cells displayed an increase in adhesion to fibronectin under elevated pressure, an effect absent in beta1-integrin-null and TT788/9AA cells. T788D substitution significantly elevated basal cell adhesion but displayed no further increase under pressure. These results suggest pressure-induced cell adhesion is mediated by beta1-integrin T788/9 phosphorylation-dependent changes in integrin binding affinity.
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Affiliation(s)
- David H Craig
- Department of Surgery, John D. Dingell VA Medical Center, 4646 John R. Street, Detroit, MI 48201-1932, USA
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Very late antigen-4 function of myeloblasts correlates with improved overall survival for patients with acute myeloid leukemia. Blood 2008; 113:866-74. [PMID: 18927435 DOI: 10.1182/blood-2007-12-124818] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Adhesion of acute myeloid leukemia (AML) blasts in the bone marrow microenvironment confers protection from chemotherapy-induced apoptosis. One mechanism for retention of blasts within the bone marrow is adhesion via very late antigen-4 (VLA-4), the alpha(4)beta(1) integrin heterodimer that binds to its main ligands, fibronectin, and vascular cell adhesion molecule-1 (VCAM-1). To examine the relationship of functional expression of VLA-4 to prognosis in AML, we studied marrow samples from 175 adult AML patients who underwent induction chemotherapy with anthracycline and cytarabine on Southwest Oncology Group trials. The studies included flow cytometry and functional in vitro assays for ligand binding and maximal beta(1) activation. VLA-4 expression varied widely, with mean expression 60.6% for alpha(4), and was not significantly associated with response to chemotherapy, relapse-free, or overall survival (OS). However, increased binding of soluble VCAM-1 via VLA-4 was significantly associated with longer OS, corrected for age (P = .033). Estimated 5-year OS was 31% (95% confidence interval, 14%-48%) in 30 patients with soluble VCAM-1 binding greater than or equal to 40%, compared with 10% (confidence interval, 3%-17%) in 72 patients with lower binding. Adhesion and migratory properties of AML blasts thus appear to influence chemosensitivity and therefore may be therapeutic targets.
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Genetic perturbation of the putative cytoplasmic membrane-proximal salt bridge aberrantly activates alpha(4) integrins. Blood 2008; 112:5007-15. [PMID: 18809756 DOI: 10.1182/blood-2008-03-144543] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
alpha(4) integrins play a pivotal role in leukocyte migration and tissue-specific homing. The ability of integrins to bind ligand is dynamically regulated by activation-dependent conformational changes triggered in the cytoplasmic domain. An NMR solution structure defined a putative membrane-proximal salt bridge between the alpha(IIb)beta(3) integrin cytoplasmic tails, which restrains integrins in their low-affinity state. However, the physiological importance of this salt bridge in alpha(4) integrin regulation remains to be elucidated. To address this question, we disrupted the salt bridge in murine germ line by mutating the conserved cytoplasmic arginine R(GFFKR) in alpha(4) integrins. In lymphocytes from knock-in mice (alpha(4)-R/A(GFFKR)), alpha(4)beta(1) and alpha(4)beta(7) integrins exhibited constitutively up-regulated ligand binding. However, transmigration of these cells across VCAM-1 and MAdCAM-1 substrates, or across endothelial monolayers, was reduced. Perturbed detachment of the tail appeared to cause the reduced cell migration of alpha(4)-R/A(GFFKR) lymphocytes. In vivo, alpha(4)-R/A(GFFKR) cells exhibited increased firm adhesion to Peyer patch venules but reduced homing to the gut. Our results demonstrate that the membrane-proximal salt bridge plays a critical role in supporting proper alpha(4) integrin adhesive dynamics. Loss of this interaction destabilizes the nonadhesive conformation, and thereby perturbs the properly balanced cycles of adhesion and deadhesion required for efficient cell migration.
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40
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Ulfman LH, Kamp VM, van Aalst CW, Verhagen LP, Sanders ME, Reedquist KA, Buitenhuis M, Koenderman L. Homeostatic intracellular-free Ca2+ is permissive for Rap1-mediated constitutive activation of alpha4 integrins on eosinophils. THE JOURNAL OF IMMUNOLOGY 2008; 180:5512-9. [PMID: 18390735 DOI: 10.4049/jimmunol.180.8.5512] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Although much progress has been made in understanding the molecular mechanisms underlying agonist-induced "inside-out" activation of integrins, little is known about how basal levels of integrin function are maintained. This is particularly important for nonactivated eosinophils, where intermediate activation of alpha(4)beta(1) integrin supports recruitment to endothelial cells under flow conditions. Depletion of intracellular Ca(2+) and pharmacological inhibition of phospholipase C (but not other intracellular signaling molecules, including PI3K, ERK1/2, p38 MAPK, and tyrosine kinase activity) abrogated basal alpha(4) integrin activity in nonactivated eosinophils. Basal alpha(4) integrin activation was associated with activation of the small GTPase Rap1, a known regulator of agonist-induced integrin function. Basal Rap activation was dependent upon phospholipase C, but not intracellular Ca(2+). However, depletion of intracellular Ca(2+) in CD34(+) hematopoietic progenitor cells abolished RapV12-mediated induction of alpha(4) integrin activity. Thus, residual Rap activity or constitutively active Rap activity in Ca(2+)-depleted cells is not sufficient to induce alpha(4) integrin activation. These data suggest that activation of functional alpha(4) integrin activity in resting eosinophils is mediated by Rap1 provided that the intracellular-free Ca(2+) is at a normal homeostatic concentration.
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Affiliation(s)
- Laurien H Ulfman
- Department of Respiratory Medicine, University Medical Center Utrecht, Utrecht, The Netherlands.
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41
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Schmitz J, Gottschalk KE. Mechanical regulation of cell adhesion. SOFT MATTER 2008; 4:1373-1387. [PMID: 32907100 DOI: 10.1039/b716805p] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Cellular adhesion against external forces is governed by both the equilibrium affinity of the involved receptor-ligand bonds and the mechanics of the cell. Certain receptors like integrins change their affinity as well as the mechanics of their anchorage to tune the adhesiveness. Whereas in the last few years the focus of integrin research has lain on the affinity regulation of the adhesion receptors, more recently the importance of cellular mechanics became apparent. Here, we focus on different aspects of the mechanical regulation of the cellular adhesiveness.
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Affiliation(s)
- Julia Schmitz
- Applied Physics, LMU München, Amalienstr. 54, 80799 München, Germany.
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42
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Chigaev A, Waller A, Amit O, Sklar LA. Galphas-coupled receptor signaling actively down-regulates alpha4beta1-integrin affinity: a possible mechanism for cell de-adhesion. BMC Immunol 2008; 9:26. [PMID: 18534032 PMCID: PMC2442041 DOI: 10.1186/1471-2172-9-26] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2007] [Accepted: 06/05/2008] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Activation of integrins in response to inside-out signaling serves as a basis for leukocyte arrest on endothelium, and migration of immune cells. Integrin-dependent adhesion is controlled by the conformational state of the molecule (i.e. change in the affinity for the ligand and molecular unbending (extension)), which is regulated by seven-transmembrane Guanine nucleotide binding Protein-Coupled Receptors (GPCRs). alpha4beta1-integrin (CD49d/CD29, Very Late Antigen-4, VLA-4) is expressed on leukocytes, hematopoietic stem cells, hematopoietic cancer cells, and others. Affinity and extension of VLA-4 are both rapidly up-regulated by inside-out signaling through several Galphai-coupled GPCRs. The goal of the current report was to study the effect of Galphas-coupled GPCRs upon integrin activation. RESULTS Using real-time fluorescent ligand binding to assess affinity and a FRET based assay to probe alpha4beta1-integrin unbending, we show that two Galphas-coupled GPCRs (H2-histamine receptor and beta2-adrenergic receptor) as well as several cAMP agonists can rapidly down modulate the affinity of VLA-4 activated through two Galphai-coupled receptors (CXCR4 and FPR) in U937 cells and primary human peripheral blood monocytes. This down-modulation can be blocked by receptor-specific antagonists. The Galphas-induced responses were not associated with changes in the expression level of the Galphai-coupled receptors. In contrast, the molecular unbending of VLA-4 was not significantly affected by Galphas-coupled GPCR signaling. In a VLA-4/VCAM-1-specific myeloid cell adhesion system, inhibition of the VLA-4 affinity change by Galphas-coupled GPCR had a statistically significant effect upon cell aggregation. CONCLUSION We conclude that Galphas-coupled GPCRs can rapidly down modulate the affinity state of VLA-4 binding pocket through a cAMP dependent pathway. This plays an essential role in the regulation of cell adhesion. We discuss several possible implications of this described phenomenon.
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Affiliation(s)
- Alexandre Chigaev
- Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA.
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Ley K. The Microcirculation in Inflammation. Microcirculation 2008. [DOI: 10.1016/b978-0-12-374530-9.00011-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
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Ley K, Laudanna C, Cybulsky MI, Nourshargh S. Getting to the site of inflammation: the leukocyte adhesion cascade updated. Nat Rev Immunol 2007; 7:678-89. [PMID: 17717539 DOI: 10.1038/nri2156] [Citation(s) in RCA: 2944] [Impact Index Per Article: 173.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Neutrophil recruitment, lymphocyte recirculation and monocyte trafficking all require adhesion and transmigration through blood-vessel walls. The traditional three steps of rolling, activation and firm adhesion have recently been augmented and refined. Slow rolling, adhesion strengthening, intraluminal crawling and paracellular and transcellular migration are now recognized as separate, additional steps. In neutrophils, a second activation pathway has been discovered that does not require signalling through G-protein-coupled receptors and the signalling steps leading to integrin activation are beginning to emerge. This Review focuses on new aspects of one of the central paradigms of inflammation and immunity--the leukocyte adhesion cascade.
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Affiliation(s)
- Klaus Ley
- Robert M. Berne Cardiovascular Research Center and Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia 22908, USA.
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45
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Chigaev A, Waller A, Zwartz GJ, Buranda T, Sklar LA. Regulation of cell adhesion by affinity and conformational unbending of alpha4beta1 integrin. THE JOURNAL OF IMMUNOLOGY 2007; 178:6828-39. [PMID: 17513731 DOI: 10.4049/jimmunol.178.11.6828] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Rapid activation of integrins in response to chemokine-induced signaling serves as a basis for leukocyte arrest on inflamed endothelium. Current models of integrin activation include increased affinity for ligand, molecular extension, and others. In this study, using real-time fluorescence resonance energy transfer to assess alpha(4)beta(1) integrin conformational unbending and fluorescent ligand binding to assess affinity, we report at least four receptor states with independent regulation of affinity and unbending. Moreover, kinetic analysis of chemokine-induced integrin conformational unbending and ligand-binding affinity revealed conditions under which the affinity change was transient whereas the unbending was sustained. In a VLA-4/VCAM-1-specific myeloid cell adhesion model system, changes in the affinity of the VLA-4-binding pocket were reflected in rapid cell aggregation and disaggregation. However, the initial rate of cell aggregation increased 9-fold upon activation, of which only 2.5-fold was attributable to the increased affinity of the binding pocket. These data show that independent regulation of affinity and conformational unbending represents a novel and fundamental mechanism for regulation of integrin-dependent adhesion in which the increased affinity appears to account primarily for the increasing lifetime of the alpha(4)beta(1) integrin/VCAM-1 bond, whereas the unbending accounts for the increased capture efficiency.
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Affiliation(s)
- Alexandre Chigaev
- Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA
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46
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DiVietro JA, Brown DC, Sklar LA, Larson RS, Lawrence MB. Immobilized Stromal Cell-Derived Factor-1α Triggers Rapid VLA-4 Affinity Increases to Stabilize Lymphocyte Tethers on VCAM-1 and Subsequently Initiate Firm Adhesion. THE JOURNAL OF IMMUNOLOGY 2007; 178:3903-11. [PMID: 17339490 DOI: 10.4049/jimmunol.178.6.3903] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The integrin VLA-4 (alpha(4)beta(1)) mediates tethering and rolling events as well as firm adhesion of leukocytes to VCAM-1. Unlike selectins, VLA-4 integrin-mediated lymphocyte adhesiveness can be modulated by chemokines through intracellular signaling pathways. To investigate the effects of the chemokine stromal cell-derived factor-1alpha (SDF-1alpha) on VLA-4-mediated lymphocyte adhesion, human PBL were flowed over VCAM-1 substrates in a parallel plate flow chamber with surface-immobilized SDF-1alpha, a potent activator of firm adhesion. The initial tethering interactions had a median lifetime of 200 ms, consistent with the half-life of low-affinity VLA-4-VCAM-1 bonds. Immobilized SDF-1alpha acted within the lifetime of a primary tether to stabilize initial tethering interactions, increasing the likelihood a PBL would remain interacting with the surface. As expected, the immobilized SDF-1alpha also increased the ratio of PBL firm adhesion to rolling. An LDV peptide-based small molecule that preferentially binds high-affinity VLA-4 reduced PBL firm adhesion to VCAM-1 by 90%. The reduction in firm adhesion due to blockage of high-affinity VLA-4 was paralleled by a 4-fold increase in the fraction of rolling PBL. Chemokine activation of PBL firm adhesion on VCAM-1 depended on induction of high-affinity VLA-4 rather than recruitment of a pre-existing pool of high-affinity VLA-4 as previously thought.
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Affiliation(s)
- Jeffrey A DiVietro
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, USA
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Taite LJ, Rowland ML, Ruffino KA, Smith BRE, Lawrence MB, West JL. Bioactive hydrogel substrates: probing leukocyte receptor-ligand interactions in parallel plate flow chamber studies. Ann Biomed Eng 2006; 34:1705-11. [PMID: 17031598 PMCID: PMC1705491 DOI: 10.1007/s10439-006-9173-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2006] [Accepted: 08/02/2006] [Indexed: 01/31/2023]
Abstract
The binding of activated integrins on the surface of leukocytes facilitates the adhesion of leukocytes to vascular endothelium during inflammation. Interactions between selectins and their ligands mediate rolling, and are believed to play an important role in leukocyte adhesion, though the minimal recognition motif required for physiologic interactions is not known. We have developed a novel system using poly(ethylene glycol) (PEG) hydrogels modified with either integrin-binding peptide sequences or the selectin ligand sialyl Lewis X (SLeX) within a parallel plate flow chamber to examine the dynamics of leukocyte adhesion to specific ligands. The adhesive peptide sequences arginine–glycine–aspartic acid–serine (RGDS) and leucine–aspartic acid–valine (LDV) as well as sialyl Lewis X were bound to the surface of photopolymerized PEG diacrylate hydrogels. Leukocytes perfused over these gels in a parallel plate flow chamber at physiological shear rates demonstrate both rolling and firm adhesion, depending on the identity and concentration of ligand bound to the hydrogel substrate. This new system provides a unique polymer-based model for the study of interactions between leukocytes and endothelium as well as a platform to develop improved scaffolds for cardiovascular tissue engineering.
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Affiliation(s)
- Lakeshia J. Taite
- Department of Bioengineering, Rice University, 6100 Main Street, MS 142, Houston, TX 77005 USA
| | - Maude L. Rowland
- Department of Bioengineering, Rice University, 6100 Main Street, MS 142, Houston, TX 77005 USA
| | - Katie A. Ruffino
- Department of Bioengineering, Rice University, 6100 Main Street, MS 142, Houston, TX 77005 USA
| | - Bryan R. E. Smith
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA USA
| | - Michael B. Lawrence
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA USA
| | - Jennifer L. West
- Department of Bioengineering, Rice University, 6100 Main Street, MS 142, Houston, TX 77005 USA
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Hyduk SJ, Chan JR, Duffy ST, Chen M, Peterson MD, Waddell TK, Digby GC, Szaszi K, Kapus A, Cybulsky MI. Phospholipase C, calcium, and calmodulin are critical for α4β1 integrin affinity up-regulation and monocyte arrest triggered by chemoattractants. Blood 2006; 109:176-84. [PMID: 16960156 DOI: 10.1182/blood-2006-01-029199] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractDuring inflammation, monocytes roll on activated endothelium and arrest after stimulation by proteoglycan-bound chemokines and other chemoattractants. We investigated signaling pathways downstream of G protein–coupled receptors (GPCRs) that are relevant to α4β1 integrin affinity up-regulation using formyl peptide receptor-transfected U937 cells stimulated with fMLP or stromal-derived factor-1α and human peripheral blood monocytes stimulated with multiple chemokines or chemoattractants. The up-regulation of soluble LDV peptide or vascular cell adhesion molecule-1 (VCAM-1) binding by these stimuli was critically dependent on activation of phospholipase C (PLC), inositol 1,4,5-triphosphate receptors, increased intracellular calcium, influx of extracellular calcium, and calmodulin, suggesting that this signaling pathway is required for α4 integrins to assume a high-affinity conformation. In fact, a rise in intracellular calcium following treatment with thapsigargin or ionomycin was sufficient to induce binding of ligand. Blockade of p44/42 and p38 mitogen-activated protein (MAP) kinases, phosphoinositide 3-kinase, or protein kinase C (PKC) signaling did not inhibit chemoattractant-induced LDV or VCAM-1 binding. However, activation of PKC by phorbol ester up-regulated α4β1 affinity with kinetics distinct from those of GPCR signaling. A critical role for PLC and calmodulin was also established for leukocyte arrest and adhesion strengthening.
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Affiliation(s)
- Sharon J Hyduk
- Department of Laboratory Medicine and Pathobiology, University of Toronto, ON, Canada
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Woodside DG, Kram RM, Mitchell JS, Belsom T, Billard MJ, McIntyre BW, Vanderslice P. Contrasting Roles for Domain 4 of VCAM-1 in the Regulation of Cell Adhesion and Soluble VCAM-1 Binding to Integrin α4β1. THE JOURNAL OF IMMUNOLOGY 2006; 176:5041-9. [PMID: 16585601 DOI: 10.4049/jimmunol.176.8.5041] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Cell adhesion mediated by the interaction between integrin alpha4beta1 and VCAM-1 is important in normal physiologic processes and in inflammatory and autoimmune disease. Numerous studies have mapped the alpha4beta1 binding sites in VCAM-1 that mediate cell adhesion; however, little is known about the regions in VCAM-1 important for regulating soluble binding. In the present study, we demonstrate that 6D VCAM-1 (an alternatively spliced isoform of VCAM-1 lacking Ig-like domain 4) binds alpha4beta1 with a higher relative affinity than does the full-length form of VCAM-1 containing 7 Ig-like extracellular domains (7D VCAM-1). In indirect binding assays, the EC50 of soluble 6D VCAM-1 binding to alpha4beta1 on Jurkat cells (in 1 mM MnCl2) was 2 x 10(-9) M, compared with 7D VCAM-1 at 11 x 10(-9) M. When used in solution to inhibit alpha4beta1 mediated cell adhesion, the IC50 of 6D VCAM-1 was 13 x 10(-9) M, compared with 7D VCAM-1 measured at 150 x 10(-9) M. Removal of Ig-like domains 4, 5, or 6, or simply substituting Asp328 in domain 4 of 7D VCAM-1 with alanine, caused increased binding of soluble 7D VCAM-1 to alpha4beta1. In contrast, cells adhered more avidly to 7D VCAM-1 under shear force, as it induced cell spreading at lower concentrations than did 6D VCAM-1. Finally, soluble 6D VCAM-1 acts as an agonist through alpha4beta1 by augmenting cell migration and inducing cell aggregation. These results indicate that the domain 4 of VCAM-1 plays a contrasting role when VCAM-1 is presented in solution or as a cell surface-expressed adhesive substrate.
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Carrasco YR, Batista FD. B-cell activation by membrane-bound antigens is facilitated by the interaction of VLA-4 with VCAM-1. EMBO J 2006; 25:889-99. [PMID: 16456548 PMCID: PMC1383545 DOI: 10.1038/sj.emboj.7600944] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2005] [Accepted: 12/14/2005] [Indexed: 02/07/2023] Open
Abstract
VCAM-1 is one of the main ligands of VLA-4, an integrin that is highly expressed on the surface of mature B cells. Here we find that coexpression of VCAM-1 on an antigen-bearing membrane facilitates B-cell activation. Firstly, this is achieved by mediating B-cell tethering, which in turn increases the likelihood of a B cell to be activated. Secondly, VLA-4 synergizes with the B-cell receptor (BCR), providing B cells with tight adhesion and enhanced signalling. This dual role of VCAM-1 in promoting B-cell activation is predominantly effective when the affinity of the BCR for the antigen is low. In addition, we show that the VCAM-1 ectodomain alone is sufficient to carry out this function. However, it requires the transmembrane domain to segregate properly into a docking structure characteristic of the B-cell immunological synapse (IS). These results show that the VLA-4/VCAM-1 interaction during membrane antigen recognition enhances B-cell activation and this function appears to be independent of its final peripheral localization at the IS.
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Affiliation(s)
- Yolanda R Carrasco
- Lymphocyte Interaction Laboratory, Cancer Research UK London Research Institute, Lincoln's Inn Fields Laboratories, London, UK
| | - Facundo D Batista
- Lymphocyte Interaction Laboratory, Cancer Research UK London Research Institute, Lincoln's Inn Fields Laboratories, London, UK
- Lymphocyte Interaction Laboratory, Cancer Research UK London Research Institute, Lincoln's Inn Fields Laboratories, 44 Lincoln's Inn Fields, London WC2A 3PX, UK. Tel.: +44 20 7269 2059; Fax: +44 20 7269 3479; E-mail:
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