201
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Rakshit S, Sivasankar S. Biomechanics of cell adhesion: how force regulates the lifetime of adhesive bonds at the single molecule level. Phys Chem Chem Phys 2014; 16:2211-23. [PMID: 24419646 DOI: 10.1039/c3cp53963f] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Cell adhesion proteins play critical roles in positioning cells during development, segregating cells into distinct tissue compartments and in maintaining tissue integrity. The principle function of these proteins is to bind cells together and resist mechanical force. Adhesive proteins also enable migrating cells to adhere and roll on surfaces even in the presence of shear forces exerted by fluid flow. Recently, several experimental and theoretical studies have provided quantitative insights into the physical mechanisms by which adhesion proteins modulate their unbinding kinetics in response to tensile force. This perspective reviews these biophysical investigations. We focus on single molecule studies of cadherins, selectins, integrins, the von Willebrand factor and FimH adhesion proteins; the effect of mechanical force on the lifetime of these interactions has been extensively characterized. We review both theoretical models and experimental investigations and discuss future directions in this exciting area of research.
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Affiliation(s)
- Sabyasachi Rakshit
- Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA.
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202
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Wide-field imaging and flow cytometric analysis of cancer cells in blood by fluorescent nanodiamond labeling and time gating. Sci Rep 2014; 4:5574. [PMID: 24994610 PMCID: PMC4081895 DOI: 10.1038/srep05574] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 06/17/2014] [Indexed: 01/15/2023] Open
Abstract
Nanodiamonds containing high density ensembles of negatively charged nitrogen-vacancy (NV−) centers are promising fluorescent biomarkers due to their excellent photostability and biocompatibility. The NV− centers in the particles have a fluorescence lifetime of up to 20 ns, which distinctly differs from those (<10 ns) of cell and tissue autofluorescence, making it possible to achieve background-free detection in vivo by time gating. Here, we demonstrate the feasibility of using fluorescent nanodiamonds (FNDs) as optical labels for wide-field time-gated fluorescence imaging and flow cytometric analysis of cancer cells with a nanosecond intensified charge-coupled device (ICCD) as the detector. The combined technique has allowed us to acquire fluorescence images of FND-labeled HeLa cells in whole blood covered with a chicken breast of ~0.1-mm thickness at the single cell level, and to detect individual FND-labeled HeLa cells in blood flowing through a microfluidic device at a frame rate of 23 Hz, as well as to locate and trace FND-labeled lung cancer cells in the blood vessels of a mouse ear. It opens a new window for real-time imaging and tracking of transplanted cells (such as stem cells) in vivo.
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203
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Schubert R, Strohmeyer N, Bharadwaj M, Ramanathan SP, Krieg M, Friedrichs J, Franz CM, Muller DJ. Assay for characterizing the recovery of vertebrate cells for adhesion measurements by single-cell force spectroscopy. FEBS Lett 2014; 588:3639-48. [PMID: 24928443 DOI: 10.1016/j.febslet.2014.06.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 05/30/2014] [Accepted: 06/02/2014] [Indexed: 11/30/2022]
Abstract
Single-cell force spectroscopy (SCFS) is becoming a widely used method to quantify the adhesion of a living cell to a substrate, another cell or tissue. The high sensitivity of SCFS permits determining the contributions of individual cell adhesion molecules (CAMs) to the adhesion force of an entire cell. However, to prepare adherent cells for SCFS, they must first be detached from tissue-culture flasks or plates. EDTA and trypsin are often applied for this purpose. Because cellular properties can be affected by this treatment, cells need to recover before being further characterized by SCFS. Here we introduce atomic force microscopy (AFM)-based SCFS to measure the mechanical and adhesive properties of HeLa cells and mouse embryonic kidney fibroblasts while they are recovering after detachment from tissue-culture. We find that mechanical and adhesive properties of both cell lines recover quickly (<10 min) after detachment using EDTA, while trypsin-detached fibroblasts require >60 min to fully recover. Our assay introduced to characterize the recovery of mammalian cells after detachment can in future be used to estimate the recovery behavior of other adherent cell types.
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Affiliation(s)
- Rajib Schubert
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, 4058 Basel, Switzerland
| | - Nico Strohmeyer
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, 4058 Basel, Switzerland
| | - Mitasha Bharadwaj
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, 4058 Basel, Switzerland
| | - Subramanian P Ramanathan
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, 4058 Basel, Switzerland
| | - Michael Krieg
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA
| | - Jens Friedrichs
- Leibniz Institute of Polymer Research Dresden, Institute for Biofunctional Polymer Materials, Hohe Str. 6, 01069 Dresden, Germany
| | - Clemens M Franz
- Karlsruhe Institute of Technology (KIT), DFG-Center for Functional Nanostructures, Wolfgang-Gaede-Str. 1a, 76131 Karlsruhe, Germany
| | - Daniel J Muller
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, 4058 Basel, Switzerland.
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204
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Sathiyanadan K, Coisne C, Enzmann G, Deutsch U, Engelhardt B. PSGL-1 and E/P-selectins are essential for T-cell rolling in inflamed CNS microvessels but dispensable for initiation of EAE. Eur J Immunol 2014; 44:2287-94. [PMID: 24740164 DOI: 10.1002/eji.201344214] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 03/24/2014] [Accepted: 04/11/2014] [Indexed: 01/25/2023]
Abstract
T-cell migration across the blood-brain barrier is a crucial step in the pathogenesis of EAE, an animal model for MS. Live cell imaging studies demonstrated that P-selectin glycoprotein ligand-1 (PSGL-1) and its endothelial ligands E- and P-selectin mediate the initial rolling of T cells in brain vessels during EAE. As functional absence of PSGL-1 or E/P-selectins does not result in ameliorated EAE, we speculated that T-cell entry into the spinal cord is independent of PSGL-1 and E/P-selectin. Performing intravital microscopy, we observed the interaction of WT or PSGL-1(-/-) proteolipid protein-specific T cells in inflamed spinal cord microvessels of WT or E/P-selectin(-/-) SJL/J mice during EAE. T-cell rolling but not T-cell capture was completely abrogated in the absence of either PSGL-1 or E- and P-selectin, resulting in a significantly reduced number of T cells able to firmly adhere in the inflamed spinal cord microvessels, but did not lead to reduced T-cell invasion into the CNS parenchyma. Thus, PSGL-1 interaction with E/P-selectin is essential for T-cell rolling in inflamed spinal cord microvessels during EAE. Taken together with previous observations, our findings show that T-cell rolling is not required for successful T-cell entry into the CNS and initiation of EAE.
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205
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Abstract
T cells are key players of the mammalian adaptive immune system. They experience different mechanical microenvironments during their life cycle, from the thymus, secondary lymph organs, and peripheral tissues that are free of externally applied force, but display variable substrate rigidities to the blood and lymphatic circulation systems, where complicated hydrodynamic forces are present. Regardless of whether T cells are subject to external forces or generate their own internal forces, they respond and adapt to different biomechanical cues to modulate their adhesion, migration, trafficking, and triggering of immune functions through mechanical regulation of various molecules that bear force. These include adhesive receptors, immunoreceptors, motor proteins, cytoskeletal proteins, and their associated molecules. Here, we discuss the forces acting on various surface and cytoplasmic proteins of a T cell in different mechanical milieus. We review existing data on how force regulates protein conformational changes and interactions with counter molecules, including integrins, actin, and the T-cell receptor, and how each relates to T-cell functions.
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Affiliation(s)
- Wei Chen
- Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, USA
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206
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Sharma AK, Shtylla B, Chowdhury D. Distribution of lifetimes of kinetochore–microtubule attachments: interplay of energy landscape, molecular motors and microtubule (de-)polymerization. Phys Biol 2014; 11:036004. [DOI: 10.1088/1478-3975/11/3/036004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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207
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Willenbrock F, Zicha D, Hoppe A, Hogg N. Novel automated tracking analysis of particles subjected to shear flow: kindlin-3 role in B cells. Biophys J 2014; 105:1110-22. [PMID: 24010654 PMCID: PMC3762340 DOI: 10.1016/j.bpj.2013.06.051] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 05/16/2013] [Accepted: 06/18/2013] [Indexed: 12/23/2022] Open
Abstract
Shear flow assays are used to mimic the influence of physiological shear force in diverse situations such as leukocyte rolling and arrest on the vasculature, capture of nanoparticles, and bacterial adhesion. Analysis of such assays usually involves manual counting, is labor-intensive, and is subject to bias. We have developed the Leukotrack program that incorporates a novel (to our knowledge) segmentation routine capable of reliable detection of cells in phase contrast images. The program also automatically tracks rolling cells in addition to those that are more firmly attached and migrating in random directions. We demonstrate its use in the analysis of lymphocyte arrest mediated by one or more active conformations of the integrin LFA-1. Activation of LFA-1 is a multistep process that depends on several proteins including kindlin-3, the protein that is mutated in leukocyte adhesion deficiency-III patients. We find that the very first stage of LFA-1-mediated attaching is unable to proceed in the absence of kindlin-3. Our evidence indicates that kindlin-3-mediated high-affinity LFA-1 controls both the early transient integrin-dependent adhesions in addition to the final stable adhesions made under flow conditions.
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208
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Rubashkin M, Ou G, Weaver VM. Deconstructing signaling in three dimensions. Biochemistry 2014; 53:2078-90. [PMID: 24649923 PMCID: PMC3985742 DOI: 10.1021/bi401710d] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Revised: 03/17/2014] [Indexed: 01/13/2023]
Abstract
Cells in vivo exist within the context of a multicellular tissue, where their behavior is governed by homo- and heterotypic cell-cell interactions, the material properties of the extracellular matrix, and the distribution of various soluble and physical factors. Most methods currently used to study and manipulate cellular behavior in vitro, however, sacrifice physiological relevance for experimental expediency. The fallacy of such approaches has been highlighted by the recent development and application of three-dimensional culture models to cell biology, which has revealed striking phenotypic differences in cell survival, migration, and differentiation in genetically identical cells simply by varying culture conditions. These perplexing findings beg the question of what constitutes a three-dimensional culture and why cells behave so differently in two- and three-dimensional culture formats. In the following review, we dissect the fundamental differences between two- and three-dimensional culture conditions. We begin by establishing a basic definition of what "three dimensions" means at different biological scales and discuss how dimensionality influences cell signaling across different length scales. We identify which three-dimensional features most potently influence intracellular signaling and distinguish between conserved biological principles that are maintained across culture conditions and cellular behaviors that are sensitive to microenvironmental context. Finally, we highlight state-of-the-art molecular tools amenable to the study of signaling in three dimensions under conditions that facilitate deconstruction of signaling in a more physiologically relevant manner.
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Affiliation(s)
- Matthew
G. Rubashkin
- Joint
Bioengineering Program, UC-Berkeley/UCSF, Center for Bioengineering
and Tissue Regeneration, Department of Surgery, University of California, San Francisco, San Francisco, California 94143, United States
| | - Guanqing Ou
- Joint
Bioengineering Program, UC-Berkeley/UCSF, Center for Bioengineering
and Tissue Regeneration, Department of Surgery, University of California, San Francisco, San Francisco, California 94143, United States
| | - Valerie M. Weaver
- Joint
Bioengineering Program, UC-Berkeley/UCSF, Center for Bioengineering
and Tissue Regeneration, Department of Surgery, University of California, San Francisco, San Francisco, California 94143, United States
- Departments
of Anatomy and Bioengineering and Therapeutic Sciences, Eli and Edythe
Broad Center of Regeneration Medicine and Stem Cell Research, and
UCSF Helen Diller Comprehensive Cancer Center, University of California, San Francisco, San Francisco, California 94143, United States
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209
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Selectins mediate small cell lung cancer systemic metastasis. PLoS One 2014; 9:e92327. [PMID: 24699516 PMCID: PMC3974710 DOI: 10.1371/journal.pone.0092327] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Accepted: 02/21/2014] [Indexed: 01/13/2023] Open
Abstract
Metastasis formation is the major reason for the extremely poor prognosis in small cell lung cancer (SCLC) patients. The molecular interaction partners regulating metastasis formation in SCLC are largely unidentified, however, from other tumor entities it is known that tumor cells use the adhesion molecules of the leukocyte adhesion cascade to attach to the endothelium at the site of the future metastasis. Using the human OH-1 SCLC line as a model, we found that these cells expressed E- and P-selectin binding sites, which could be in part attributed to the selectin binding carbohydrate motif sialyl Lewis A. In addition, protein backbones known to carry these glycotopes in other cell lines including PSGL-1, CD44 and CEA could be detected in in vitro and in vivo grown OH1 SCLC cells. By intravital microscopy of murine mesenterial vasculature we could capture SCLC cells while rolling along vessel walls demonstrating that SCLC cells mimic leukocyte rolling behavior in terms of selectin and selectin ligand interaction in vivo indicating that this mechanism might indeed be important for SCLC cells to seed distant metastases. Accordingly, formation of spontaneous distant metastases was reduced by 50% when OH-1 cells were xenografted into E-/P-selectin-deficient mice compared with wild type mice (p = 0.0181). However, as metastasis formation was not completely abrogated in selectin deficient mice, we concluded that this adhesion cascade is redundant and that other molecules of this cascade mediate metastasis formation as well. Using several of these adhesion molecules as interaction partners presumably make SCLC cells so highly metastatic.
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210
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Angiari S, Donnarumma T, Rossi B, Dusi S, Pietronigro E, Zenaro E, Della Bianca V, Toffali L, Piacentino G, Budui S, Rennert P, Xiao S, Laudanna C, Casasnovas JM, Kuchroo VK, Constantin G. TIM-1 glycoprotein binds the adhesion receptor P-selectin and mediates T cell trafficking during inflammation and autoimmunity. Immunity 2014; 40:542-53. [PMID: 24703780 DOI: 10.1016/j.immuni.2014.03.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 03/12/2014] [Indexed: 12/24/2022]
Abstract
Selectins play a central role in leukocyte trafficking by mediating tethering and rolling on vascular surfaces. Here we have reported that T cell immunoglobulin and mucin domain 1 (TIM-1) is a P-selectin ligand. We have shown that human and murine TIM-1 binds to P-selectin, and that TIM-1 mediates tethering and rolling of T helper 1 (Th1) and Th17, but not Th2 and regulatory T cells on P-selectin. Th1 and Th17 cells lacking the TIM-1 mucin domain showed reduced rolling in thrombin-activated mesenteric venules and inflamed brain microcirculation. Inhibition of TIM-1 had no effect on naive T cell homing, but it reduced T cell recruitment in a skin hypersensitivity model and blocked experimental autoimmune encephalomyelitis. Uniquely, the TIM-1 immunoglobulin variable domain was also required for P-selectin binding. Our data demonstrate that TIM-1 is a major P-selectin ligand with a specialized role in T cell trafficking during inflammatory responses and the induction of autoimmune disease.
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Affiliation(s)
- Stefano Angiari
- Department of Pathology and Diagnostics, University of Verona, Strada le Grazie 8, 37134 Verona, Italy
| | - Tiziano Donnarumma
- Department of Pathology and Diagnostics, University of Verona, Strada le Grazie 8, 37134 Verona, Italy
| | - Barbara Rossi
- Department of Pathology and Diagnostics, University of Verona, Strada le Grazie 8, 37134 Verona, Italy
| | - Silvia Dusi
- Department of Pathology and Diagnostics, University of Verona, Strada le Grazie 8, 37134 Verona, Italy
| | - Enrica Pietronigro
- Department of Pathology and Diagnostics, University of Verona, Strada le Grazie 8, 37134 Verona, Italy
| | - Elena Zenaro
- Department of Pathology and Diagnostics, University of Verona, Strada le Grazie 8, 37134 Verona, Italy
| | - Vittorina Della Bianca
- Department of Pathology and Diagnostics, University of Verona, Strada le Grazie 8, 37134 Verona, Italy
| | - Lara Toffali
- Department of Pathology and Diagnostics, University of Verona, Strada le Grazie 8, 37134 Verona, Italy; The Center for Biomedical Computing (CBMC), University of Verona, Strada le Grazie 8, 37134 Verona, Italy
| | - Gennj Piacentino
- Department of Pathology and Diagnostics, University of Verona, Strada le Grazie 8, 37134 Verona, Italy
| | - Simona Budui
- Department of Pathology and Diagnostics, University of Verona, Strada le Grazie 8, 37134 Verona, Italy
| | - Paul Rennert
- Department of Molecular Discovery and Immunobiology, Biogen Idec Inc., 12 Cambridge Center, Cambridge, MA 02146, USA
| | - Sheng Xiao
- Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, 77 Avenue Louis Pasteur, HIM 785, Boston, MA 02115-5817, USA
| | - Carlo Laudanna
- Department of Pathology and Diagnostics, University of Verona, Strada le Grazie 8, 37134 Verona, Italy; The Center for Biomedical Computing (CBMC), University of Verona, Strada le Grazie 8, 37134 Verona, Italy
| | - Jose M Casasnovas
- Centro Nacional de Biotecnología, CNB-CSIC, Campus UAM, C/ Darwin, 3, Campus of Cantoblanco, E-28049 Madrid, Spain
| | - Vijay K Kuchroo
- Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, 77 Avenue Louis Pasteur, HIM 785, Boston, MA 02115-5817, USA
| | - Gabriela Constantin
- Department of Pathology and Diagnostics, University of Verona, Strada le Grazie 8, 37134 Verona, Italy.
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211
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The role of fucosylation in the promotion of endothelial progenitor cells in neovascularization and bone repair. Biomaterials 2014; 35:3777-85. [DOI: 10.1016/j.biomaterials.2014.01.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 01/09/2014] [Indexed: 01/07/2023]
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212
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213
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Catch and release: how do kinetochores hook the right microtubules during mitosis? Trends Genet 2014; 30:150-9. [PMID: 24631209 DOI: 10.1016/j.tig.2014.02.004] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Revised: 02/13/2014] [Accepted: 02/14/2014] [Indexed: 11/22/2022]
Abstract
Sport fishermen keep tension on their lines to prevent hooked fish from releasing. A molecular version of this angler's trick, operating at kinetochores, ensures accuracy during mitosis: the mitotic spindle attaches randomly to chromosomes and then correctly bioriented attachments are stabilized due to the tension exerted on them by opposing microtubules. Incorrect attachments, which lack tension, are unstable and release quickly, allowing another chance for biorientation. Stabilization of molecular interactions by tension also occurs in other physiological contexts, such as cell adhesion, motility, hemostasis, and tissue morphogenesis. Here, we review models for the stabilization of kinetochore attachments with an eye toward emerging models for other force-activated systems. Although attention in the mitosis field has focused mainly on one kinase-based mechanism, multiple mechanisms may act together to stabilize properly bioriented kinetochores and some principles governing other tension-sensitive systems may also apply to kinetochores.
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214
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Radtke M, Radtke M, Netz R. Shear-induced dynamics of polymeric globules at adsorbing homogeneous and inhomogeneous surfaces. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2014; 37:20. [PMID: 24676864 DOI: 10.1140/epje/i2014-14020-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 03/13/2014] [Accepted: 03/14/2014] [Indexed: 06/03/2023]
Abstract
The dynamics and adsorption behavior of a single collapsed homopolymer on a surface in shear flow is investigated by means of Brownian hydrodynamics simulations. We study different homogeneous and inhomogeneous surface models and determine dynamic state diagrams as a function of the cohesive strength, the adhesive strength, and the shear rate. We find distinct dynamical adsorbed states that are classified into rolling and slipping states, globular and coil-like states, as well as isotropic and prolate states. We identify two different cyclic processes based on trajectories of the polymer stretching and the polymer separation from the surface. For adsorption on an inhomogeneous surface consisting of discrete binding sites, we observe stick-roll motion for highly corrugated surface potentials. Although the resulting high surface friction leads to low drift velocities and reduced hydrodynamic lift forces on such inhomogeneous surfaces, a shear-induced adsorption is not found in the presence of full hydrodynamic interactions. A hydrodynamically stagnant surface model is introduced for which shear-induced adsorption is observed in the absence of hydrodynamic interactions.
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Affiliation(s)
- Matthias Radtke
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany,
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215
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Enhanced assay of endothelial exocytosis using extracellular matrix components. Anal Biochem 2014; 452:19-24. [PMID: 24561025 DOI: 10.1016/j.ab.2014.02.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 02/07/2014] [Accepted: 02/11/2014] [Indexed: 01/05/2023]
Abstract
Vascular inflammation plays a key role in the pathogenesis of atherosclerosis. The first step in vascular inflammation is endothelial exocytosis, in which endothelial granules fuse with the plasma membrane, releasing prothrombotic and proinflammatory messenger molecules. The development of cell culture models to study endothelial exocytosis has been challenging because the factors that modulate exocytosis in vitro are not well understood. Here we report a method for studying endothelial exocytosis that optimizes extracellular matrix components, cell density, and duration of culture. Human umbilical vein endothelial cells plated on collagen I-coated plates and cultured in the confluent state for 7-12 days in low-serum medium showed robust secretion of von Willebrand factor when stimulated with various agonists. This exocytosis assay is rapid and applicable to high-throughput screening.
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216
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Choi S, Levy O, Coelho MB, M.S.Cabral J, Karp JM, Karnik R. A cell rolling cytometer reveals the correlation between mesenchymal stem cell dynamic adhesion and differentiation state. LAB ON A CHIP 2014; 14:161-6. [PMID: 24146063 PMCID: PMC3886723 DOI: 10.1039/c3lc50923k] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
This communication presents quantitative studies of the dynamic adhesion behavior of mesenchymal stem cells (MSCs) enabled by the combination of cell-surface receptor-ligand interactions and three-dimensional hydrodynamic control by microtopography.
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Affiliation(s)
- Sungyoung Choi
- Department of Mechanical Engineering, Massachusetts Institute of Technology 77 Massachusetts Ave, Cambridge MA 02139
- Department of Biomedical Engineering, Kyung Hee University 1732 Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do 446-701, Republic of Korea
| | - Oren Levy
- Division of Biomedical Engineering, Department of Medicine, Center for Regenerative Therapeutics, Brigham and Women's Hospital, Harvard Medical School, Harvard Stem Cell Institute, Harvard-MIT Division of Health Sciences and Technology 65 Landsdowne St Cambridge MA 02139
| | - Mónica B. Coelho
- Division of Biomedical Engineering, Department of Medicine, Center for Regenerative Therapeutics, Brigham and Women's Hospital, Harvard Medical School, Harvard Stem Cell Institute, Harvard-MIT Division of Health Sciences and Technology 65 Landsdowne St Cambridge MA 02139
| | - Joaquim M.S.Cabral
- Department of Bioengineering, Instituto Superior Técnico, Technical University of Lisbon Av. Rovisco Pais, 1049-001 Lisboa, Portugal
| | - Jeffrey M. Karp
- Division of Biomedical Engineering, Department of Medicine, Center for Regenerative Therapeutics, Brigham and Women's Hospital, Harvard Medical School, Harvard Stem Cell Institute, Harvard-MIT Division of Health Sciences and Technology 65 Landsdowne St Cambridge MA 02139
- ;
| | - Rohit Karnik
- Department of Mechanical Engineering, Massachusetts Institute of Technology 77 Massachusetts Ave, Cambridge MA 02139
- ;
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217
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Woelke AL, Kuehne C, Meyer T, Galstyan G, Dernedde J, Knapp EW. Understanding selectin counter-receptor binding from electrostatic energy computations and experimental binding studies. J Phys Chem B 2013; 117:16443-54. [PMID: 24304345 DOI: 10.1021/jp4099123] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Higher organisms defend themselves against invading micro-organisms and harmful substances with their immune system. Key players of the immune system are the white blood cells (WBC), which in case of infection move in an extravasation process from blood vessels toward infected tissue promoting inflammation. This process starts with the attachment of the WBC to the blood vessel wall, mediated by protein pair interactions of selectins and counter-receptors (C-R). Individual selectin C-R binding is weak and varies only moderately between the three selectin types. Multivalency enhances such small differences, rendering selectin-binding type specific. In this work, we study selectin C-R binding, the initial step of extravasation. We performed electrostatic energy computations based on the crystal structure of one selectin type co-crystallized with the ligating part of the C-R. The agreement with measured free energies of binding is satisfactory. Additionally, we modeled selectin mutant structures in order to explain differences in binding of the different selectin types. To verify our modeling procedures, surface plasmon resonance data were measured for several mutants and compared with computed binding affinities. Binding affinities computed with soaked rather than co-crystallized selectin C-R structures do not agree with measured data. Hence, these structures are inappropriate to describe the binding mode. The analysis of selectin/C-R binding unravels the role played by individual molecular components in the binding event. This opens new avenues to prevent immune system malfunction, designing drugs that can control inflammatory processes by moderating selectin C-R binding.
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Affiliation(s)
- Anna Lena Woelke
- Institute of Chemistry and Biochemistry, Freie Universität Berlin , D-14195 Berlin, Germany
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218
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Xu T, Liu W, Luo J, Li C, Ba X, Ampah KK, Wang X, Jiang Y, Zeng X. Lipid Raft is required for PSGL-1 ligation induced HL-60 cell adhesion on ICAM-1. PLoS One 2013; 8:e81807. [PMID: 24312591 PMCID: PMC3849276 DOI: 10.1371/journal.pone.0081807] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2013] [Accepted: 10/16/2013] [Indexed: 01/03/2023] Open
Abstract
P-selectin glycoprotein ligand-1 (PSGL-1) and integrins are adhesion molecules that play critical roles in host defense and innate immunity. PSGL-1 mediates leukocyte rolling and primes leukocytes for integrin-mediated adhesion. However, the mechanism that PSGL-1 as a rolling receptor in regulating integrin activation has not been well characterized. Here, we investigate the function of lipid raft in regulating PSGL-1 induced β2 integrin-mediated HL-60 cells adhesion. PSGL-1 ligation with antibody enhances the β2 integrin activation and β2 integrin-dependent adhesion to ICAM-1. Importantly, with the treatment of methyl-β-cyclodextrin (MβCD), we confirm the role of lipid raft in regulating the activation of β2 integrin. Furthermore, we find that the protein level of PSGL-1 decreased in raft fractions in MβCD treated cells. PSGL-1 ligation induces the recruitment of spleen tyrosine kinase (Syk), a tyrosine kinase and Vav1 (the pivotal downstream effector of Syk signaling pathway involved in cytoskeleton regulation) to lipid raft. Inhibition of Syk activity with pharmacologic inhibitor strongly reduces HL-60 cells adhesion, implicating Syk is crucial for PSGL-1 mediated β2 integrin activation. Taken together, we report that ligation of PSGL-1 on HL-60 cells activates β2 integrin, for which lipid raft integrity and Syk activation are responsible. These findings have shed new light on the mechanisms that connect leukocyte initial rolling with subsequent adhesion.
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Affiliation(s)
- Tingshuang Xu
- Institute of Genetics and Cytology, Northeast Normal University, Changchun, Jilin Province, China
| | - Wenai Liu
- Institute of Genetics and Cytology, Northeast Normal University, Changchun, Jilin Province, China
| | - Jixian Luo
- Department of Bioscience, Shanxi University, Taiyuan, China
| | - Chunfeng Li
- Institute of Genetics and Cytology, Northeast Normal University, Changchun, Jilin Province, China
| | - Xueqing Ba
- Institute of Genetics and Cytology, Northeast Normal University, Changchun, Jilin Province, China
| | - Khamal Kwesi Ampah
- Institute of Genetics and Cytology, Northeast Normal University, Changchun, Jilin Province, China
| | - Xiaoguang Wang
- Department of Bioscience, Changchun Teachers College, Changchun, China
- * E-mail: (XGW); (XLZ)
| | - Yong Jiang
- Department of Pathophysiology, Southern Medical University, Guangzhou, China
| | - Xianlu Zeng
- Institute of Genetics and Cytology, Northeast Normal University, Changchun, Jilin Province, China
- * E-mail: (XGW); (XLZ)
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Ito Y, Vela JL, Matsumura F, Hoshino H, Tyznik A, Lee H, Girardi E, Zajonc DM, Liddington R, Kobayashi M, Bao X, Bugaytsova J, Borén T, Jin R, Zong Y, Seeberger PH, Nakayama J, Kronenberg M, Fukuda M. Helicobacter pylori cholesteryl α-glucosides contribute to its pathogenicity and immune response by natural killer T cells. PLoS One 2013; 8:e78191. [PMID: 24312443 PMCID: PMC3846475 DOI: 10.1371/journal.pone.0078191] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 09/09/2013] [Indexed: 12/31/2022] Open
Abstract
Approximately 10–15% of individuals infected with Helicobacter pylori will develop ulcer disease (gastric or duodenal ulcer), while most people infected with H. pylori will be asymptomatic. The majority of infected individuals remain asymptomatic partly due to the inhibition of synthesis of cholesteryl α-glucosides in H. pylori cell wall by α1,4-GlcNAc-capped mucin O-glycans, which are expressed in the deeper portion of gastric mucosa. However, it has not been determined how cholesteryl α-glucosyltransferase (αCgT), which forms cholesteryl α-glucosides, functions in the pathogenesis of H. pylori infection. Here, we show that the activity of αCgT from H. pylori clinical isolates is highly correlated with the degree of gastric atrophy. We investigated the role of cholesteryl α-glucosides in various aspects of the immune response. Phagocytosis and activation of dendritic cells were observed at similar degrees in the presence of wild-type H. pylori or variants harboring mutant forms of αCgT showing a range of enzymatic activity. However, cholesteryl α-glucosides were recognized by invariant natural killer T (iNKT) cells, eliciting an immune response in vitro and in vivo. Following inoculation of H. pylori harboring highly active αCgT into iNKT cell-deficient (Jα18−/−) or wild-type mice, bacterial recovery significantly increased in Jα18−/− compared to wild-type mice. Moreover, cytokine production characteristic of Th1 and Th2 cells dramatically decreased in Jα18−/− compared to wild-type mice. These findings demonstrate that cholesteryl α-glucosides play critical roles in H. pylori-mediated gastric inflammation and precancerous atrophic gastritis.
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Affiliation(s)
- Yuki Ito
- Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
| | - Jose Luis Vela
- La Jolla Institute for Allergy & Immunology, La Jolla, California, United States of America
| | - Fumiko Matsumura
- Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
| | - Hitomi Hoshino
- Department of Molecular Pathology, Shinshu University Graduate School of Medicine, Matsumoto, Nagano, Japan
| | - Aaron Tyznik
- La Jolla Institute for Allergy & Immunology, La Jolla, California, United States of America
| | - Heeseob Lee
- Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
| | - Enrico Girardi
- La Jolla Institute for Allergy & Immunology, La Jolla, California, United States of America
| | - Dirk M. Zajonc
- La Jolla Institute for Allergy & Immunology, La Jolla, California, United States of America
| | - Robert Liddington
- Infectious and Inflammatory Disease Center, Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
| | - Motohiro Kobayashi
- Department of Molecular Pathology, Shinshu University Graduate School of Medicine, Matsumoto, Nagano, Japan
| | - Xingfeng Bao
- Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
| | - Jeanna Bugaytsova
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Thomas Borén
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Rongsheng Jin
- Del E. Webb Neuroscience, Aging and Stem Cell Research Center, Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
| | - Yinong Zong
- Del E. Webb Neuroscience, Aging and Stem Cell Research Center, Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
| | - Peter H. Seeberger
- Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
| | - Jun Nakayama
- Department of Molecular Pathology, Shinshu University Graduate School of Medicine, Matsumoto, Nagano, Japan
| | - Mitchell Kronenberg
- La Jolla Institute for Allergy & Immunology, La Jolla, California, United States of America
| | - Minoru Fukuda
- Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
- * E-mail:
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Kruss S, Erpenbeck L, Amschler K, Mundinger TA, Boehm H, Helms HJ, Friede T, Andrews RK, Schön MP, Spatz JP. Adhesion maturation of neutrophils on nanoscopically presented platelet glycoprotein Ibα. ACS NANO 2013; 7:9984-96. [PMID: 24093566 PMCID: PMC4122703 DOI: 10.1021/nn403923h] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Neutrophilic granulocytes play a fundamental role in cardiovascular disease. They interact with platelet aggregates via the integrin Mac-1 and the platelet receptor glycoprotein Ibα (GPIbα). In vivo, GPIbα presentation is highly variable under different physiological and pathophysiological conditions. Here, we quantitatively determined the conditions for neutrophil adhesion in a biomimetic in vitro system, which allowed precise adjustment of the spacings between human GPIbα presented on the nanoscale from 60 to 200 nm. Unlike most conventional nanopatterning approaches, this method provided control over the local receptor density (spacing) rather than just the global receptor density. Under physiological flow conditions, neutrophils required a minimum spacing of GPIbα molecules to successfully adhere. In contrast, under low-flow conditions, neutrophils adhered on all tested spacings with subtle but nonlinear differences in cell response, including spreading area, spreading kinetics, adhesion maturation, and mobility. Surprisingly, Mac-1-dependent neutrophil adhesion was very robust to GPIbα density variations up to 1 order of magnitude. This complex response map indicates that neutrophil adhesion under flow and adhesion maturation are differentially regulated by GPIbα density. Our study reveals how Mac-1/GPIbα interactions govern cell adhesion and how neutrophils process the number of available surface receptors on the nanoscale. In the future, such in vitro studies can be useful to determine optimum therapeutic ranges for targeting this interaction.
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Affiliation(s)
- Sebastian Kruss
- Department of New Materials and Biosystems, Max Planck Institute for Intelligent Systems, and Institute of Physical Chemistry, Heidelberg University, Heisenbergstraße 3, Stuttgart 70569, Germany
| | - Luise Erpenbeck
- Department of Dermatology, Venereology and Allergology, University Medical Center Göttingen, 40 Robert-Koch-Straße, Göttingen 37075, Germany
| | - Katharina Amschler
- Department of Dermatology, Venereology and Allergology, University Medical Center Göttingen, 40 Robert-Koch-Straße, Göttingen 37075, Germany
| | - Tabea A. Mundinger
- Department of New Materials and Biosystems, Max Planck Institute for Intelligent Systems, and Institute of Physical Chemistry, Heidelberg University, Heisenbergstraße 3, Stuttgart 70569, Germany
| | - Heike Boehm
- Department of New Materials and Biosystems, Max Planck Institute for Intelligent Systems, and Institute of Physical Chemistry, Heidelberg University, Heisenbergstraße 3, Stuttgart 70569, Germany
| | - Hans-Joachim Helms
- Department of Medical Statistics, University Medical Center Göttingen, 32 Humboldtallee, Göttingen 37073, Germany
| | - Tim Friede
- Department of Medical Statistics, University Medical Center Göttingen, 32 Humboldtallee, Göttingen 37073, Germany
| | - Robert K. Andrews
- Australian Center for Blood Diseases, Monash University, 89 Commercial Road, Melbourne 3004, Australia
| | - Michael P. Schön
- Department of Dermatology, Venereology and Allergology, University Medical Center Göttingen, 40 Robert-Koch-Straße, Göttingen 37075, Germany
- Address correspondence to ,
| | - Joachim P. Spatz
- Department of New Materials and Biosystems, Max Planck Institute for Intelligent Systems, and Institute of Physical Chemistry, Heidelberg University, Heisenbergstraße 3, Stuttgart 70569, Germany
- Address correspondence to ,
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Orden S, De Pablo C, Rios-Navarro C, Martinez-Cuesta MA, Peris JE, Barrachina MD, Esplugues JV, Alvarez A. Efavirenz induces interactions between leucocytes and endothelium through the activation of Mac-1 and gp150,95. J Antimicrob Chemother 2013; 69:995-1004. [PMID: 24275118 DOI: 10.1093/jac/dkt468] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
OBJECTIVES The potential cardiovascular (CV) toxicity associated with combined antiretroviral therapy (cART) has been attributed mainly to the nucleoside reverse transcriptase inhibitors abacavir and didanosine. However, the other two components of cART--non-nucleoside reverse transcriptase inhibitors (NNRTIs) and protease inhibitors (PIs)--may also be implicated, either directly or by influencing the action of the other drugs. This study evaluates the acute direct effects of the NNRTIs efavirenz and nevirapine and one of the most widely employed PIs, lopinavir, on leucocyte-endothelium interactions, a hallmark of CV disease. METHODS Drugs were analysed in vitro in human cells (interactions of peripheral blood polymorphonuclear or mononuclear cells with human umbilical vein endothelial cells) using a flow chamber system, and in vivo in rat mesenteric vessels by means of intravital microscopy. The expression of adhesion molecules in leucocytes and endothelial cells was studied by flow cytometry, and the role of these molecules in white cell recruitment was evaluated by pre-treating human cells or rats with blocking antibodies. RESULTS Efavirenz and nevirapine, but not lopinavir, increased the rolling flux and adhesion of leucocytes in vitro and in vivo while inducing emigration in rat venules. Efavirenz, but not nevirapine, augmented the levels of CD11b, CD11c and CD18 in neutrophils and monocytes. The actions of efavirenz, but not of nevirapine, were reversed by antibodies against Mac-1 (CD11b/CD18), gp150,95 (CD11c/CD18) or ICAM-1 (CD54). CONCLUSIONS NNRTIs, but not PIs, interfere with leucocyte-endothelial interactions. However, differences between efavirenz and nevirapine suggest a specific CV profile for each compound.
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Affiliation(s)
- Samuel Orden
- Departamento de Farmacología and CIBERehd, Facultad de Medicina, Universidad de Valencia, Valencia, Spain
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222
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Human multipotent adult progenitor cells transcriptionally regulate fucosyltransferase VII. Cytotherapy 2013; 16:566-75. [PMID: 24176542 DOI: 10.1016/j.jcyt.2013.08.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 07/09/2013] [Accepted: 08/09/2013] [Indexed: 01/13/2023]
Abstract
BACKGROUND AIMS Targeted recruitment of leukocytes to sites of inflammation is a crucial event in normal host defense against pathogens, and attachment to and rolling on activated endothelial cells is a prerequisite first step for eventual leukocyte extravasation into sites of inflammation. These key events are mediated by interactions between glycosylated ligands expressed on leukocytes and selectins expressed on activated endothelium. Cell surface expression of selectin ligands on leukocytes is regulated by the rate-limiting enzyme fucosyltransferase VII (Fut7), and in its absence extravasation of leukocytes is severely inhibited. Multipotent adult progenitor cells (MAPCs) are an adherent cell population isolated from adult bone marrow. Intravenous administration of MAPCs provided functional improvement in multiple pre-clinical models of injury or disease, but the mechanisms by which these outcomes were achieved remain poorly understood. METHODS In vitro cell analysis studies including fluorescence-activated cell sorting, messenger RNA analysis, T-cell proliferation assays and endothelial cell binding assays were performed. RESULTS The in vitro cell analysis studies characterized the ability of MAPCs to secrete factors that transcriptionally attenuate expression of Fut7 in T cells, blocking the terminal fucosylation event in the biosynthesis of selectin ligands and reducing T-cell binding to endothelial cells. CONCLUSIONS This study presents the first example of a distinct regulatory mechanism involving transcriptional down-regulation of Fut7 by MAPCs that could modulate the trafficking behavior of T cells in vivo.
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223
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Raborn J, Fu T, Wu X, Xiu Z, Li G, Luo BH. Variation in one residue associated with the metal ion-dependent adhesion site regulates αIIbβ3 integrin ligand binding affinity. PLoS One 2013; 8:e76793. [PMID: 24116162 PMCID: PMC3792891 DOI: 10.1371/journal.pone.0076793] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 08/29/2013] [Indexed: 01/06/2023] Open
Abstract
The Asp of the RGD motif of the ligand coordinates with the β I domain metal ion dependent adhesion site (MIDAS) divalent cation, emphasizing the importance of the MIDAS in ligand binding. There appears to be two distinct groups of integrins that differ in their ligand binding affinity and adhesion ability. These differences may be due to a specific residue associated with the MIDAS, particularly the β3 residue Ala252 and corresponding Ala in the β1 integrin compared to the analogous Asp residue in the β2 and β7 integrins. Interestingly, mutations in the adjacent to MIDAS (ADMIDAS) of integrins α4β7 and αLβ2 increased the binding and adhesion abilities compared to the wild-type, while the same mutations in the α2β1, α5β1, αVβ3, and αIIbβ3 integrins demonstrated decreased ligand binding and adhesion. We introduced a mutation in the αIIbβ3 to convert this MIDAS associated Ala252 to Asp. By combination of this mutant with mutations of one or two ADMIDAS residues, we studied the effects of this residue on ligand binding and adhesion. Then, we performed molecular dynamics simulations on the wild-type and mutant αIIbβ3 integrin β I domains, and investigated the dynamics of metal ion binding sites in different integrin-RGD complexes. We found that the tendency of calculated binding free energies was in excellent agreement with the experimental results, suggesting that the variation in this MIDAS associated residue accounts for the differences in ligand binding and adhesion among different integrins, and it accounts for the conflicting results of ADMIDAS mutations within different integrins. This study sheds more light on the role of the MIDAS associated residue pertaining to ligand binding and adhesion and suggests that this residue may play a pivotal role in integrin-mediated cell rolling and firm adhesion.
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Affiliation(s)
- Joel Raborn
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, United States of America
- University of Alabama at Birmingham School of Medicine, Birmingham, Alabama, United States of America
| | - Ting Fu
- Laboratory of Molecular Modeling and Design, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, PR China
- Department of Bioscience and Biotechnology, Dalian University of Technology, Dalian, PR China
- Graduate University of the Chinese Academy of Sciences, Beijing, P. R. China
| | - Xue Wu
- Laboratory of Molecular Modeling and Design, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, PR China
- Department of Bioscience and Biotechnology, Dalian University of Technology, Dalian, PR China
| | - Zhilong Xiu
- Department of Bioscience and Biotechnology, Dalian University of Technology, Dalian, PR China
| | - Guohui Li
- Laboratory of Molecular Modeling and Design, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, PR China
- * E-mail: (GL); (BL)
| | - Bing-Hao Luo
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, United States of America
- * E-mail: (GL); (BL)
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Litvinov RI, Weisel JW. Shear strengthens fibrin: the knob-hole interactions display 'catch-slip' kinetics. J Thromb Haemost 2013; 11:1933-5. [PMID: 23937213 PMCID: PMC5157126 DOI: 10.1111/jth.12374] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Accepted: 07/30/2013] [Indexed: 12/14/2022]
Affiliation(s)
- R I Litvinov
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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225
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Elevated CXCL1 expression in gp130-deficient endothelial cells impairs neutrophil migration in mice. Blood 2013; 122:3832-42. [PMID: 24081661 DOI: 10.1182/blood-2012-12-473835] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Neutrophils emigrate from venules to sites of infection or injury in response to chemotactic gradients. How these gradients form is not well understood. Some IL-6 family cytokines stimulate endothelial cells to express adhesion molecules and chemokines that recruit leukocytes. Receptors for these cytokines share the signaling subunit gp130. We studied knockout mice lacking gp130 in endothelial cells. Unexpectedly, gp130-deficient endothelial cells constitutively expressed more CXCL1 in vivo and in vitro, and even more upon stimulation with tumor necrosis factor-α. Mobilization of this increased CXCL1 from intracellular stores to the venular surface triggered β2 integrin-dependent arrest of neutrophils rolling on selectins but impaired intraluminal crawling and transendothelial migration. Superfusing CXCL1 over venules promoted neutrophil migration only after intravenously injecting mAb to CXCL1 to diminish its intravascular function or heparinase to release CXCL1 from endothelial proteoglycans. Remarkably, mice lacking gp130 in endothelial cells had impaired histamine-induced venular permeability, which was restored by injecting anti-P-selectin mAb to prevent neutrophil rolling and arrest. Thus, excessive CXCL1 expression in gp130-deficient endothelial cells augments neutrophil adhesion but hinders migration, most likely by disrupting chemotactic gradients. Our data define a role for endothelial cell gp130 in regulating integrin-dependent adhesion and de-adhesion of neutrophils during inflammation.
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226
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Mechanochemitry: a molecular biomechanics view of mechanosensing. Ann Biomed Eng 2013; 42:388-404. [PMID: 24006131 DOI: 10.1007/s10439-013-0904-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 08/28/2013] [Indexed: 12/27/2022]
Abstract
Molecular biomechanics includes two themes: the study of mechanical aspects of biomolecules and the study of molecular biology of the cell using mechanical tools. The two themes are interconnected for obvious reasons. The present review focuses on one of the interconnected areas-the mechanical regulation of molecular interaction and conformational change. Recent conceptual developments are summarized, including catch bonds, regulation of molecular interaction by the history of force application, and cyclic mechanical reinforcement. These studies elucidate the mechanochemistry of some of the candidate mechanosensing molecules, thereby providing a natural connection to mechanobiology.
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227
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Cao TM, Takatani T, King MR. Effect of extracellular pH on selectin adhesion: theory and experiment. Biophys J 2013; 104:292-9. [PMID: 23442851 DOI: 10.1016/j.bpj.2012.12.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Revised: 11/28/2012] [Accepted: 12/03/2012] [Indexed: 10/27/2022] Open
Abstract
Selectins mediate circulatory leukocyte trafficking to sites of inflammation and trauma, and the extracellular microenvironments at these sites often become acidic. In this study, we investigated the influence of slightly acidic pH on the binding dynamics of selectins (P-, L-, and E-selectin) to P-selectin glycoprotein ligand-1 (PSGL-1) via computational modeling (molecular dynamics) and experimental rolling assays under shear in vitro. The P-selectin/PSGL-1 binding is strengthened at acidic pH, as evidenced by the formation of a new hydrogen bond (seen computationally) and the observed decrease in the rolling velocities of model cells. In the case of L-selectin/PSGL-1 binding dynamics, the binding strength and frequency increase at acidic pH, as indicated by the greater cell-rolling flux of neutrophils and slower rolling velocities of L-selectin-coated microspheres, respectively. The cell flux is most likely due to an increased population of L-selectin in the high-affinity conformation as pH decreases, whereas the velocities are due to increased L-selectin/PSGL-1 contacts. In contrast to P- and L-selectin, the E-selectin/PSGL-1 binding does not exhibit significant changes at acidic pH levels, as shown both experimentally and computationally.
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Affiliation(s)
- Thong M Cao
- Department of Biomedical Engineering, Cornell University, Ithaca, New York, USA
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228
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Wang L, Asghar W, Demirci U, Wan Y. Nanostructured substrates for isolation of circulating tumor cells. NANO TODAY 2013; 8:347-387. [PMID: 24944563 PMCID: PMC4059613 DOI: 10.1016/j.nantod.2013.07.001] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Circulating tumor cells (CTCs) originate from the primary tumor mass and enter into the peripheral bloodstream. CTCs hold the key to understanding the biology of metastasis and also play a vital role in cancer diagnosis, prognosis, disease monitoring, and personalized therapy. However, CTCs are rare in blood and hard to isolate. Additionally, the viability of CTCs can easily be compromised under high shear stress while releasing them from a surface. The heterogeneity of CTCs in biomarker expression makes their isolation quite challenging; the isolation efficiency and specificity of current approaches need to be improved. Nanostructured substrates have emerged as a promising biosensing platform since they provide better isolation sensitivity at the cost of specificity for CTC isolation. This review discusses major challenges faced by CTC isolation techniques and focuses on nanostructured substrates as a platform for CTC isolation.
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Affiliation(s)
- Lixue Wang
- Department of Oncology, The Second Affiliated Hospital of Southeast University, Southeast University, Nanjing, Jiangsu 210003, PR China
| | - Waseem Asghar
- Bio-Acoustic MEMS in Medicine (BAMM) Laboratories, Center for Biomedical Engineering, Renal Division and Division of Infectious Diseases, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Utkan Demirci
- Bio-Acoustic MEMS in Medicine (BAMM) Laboratories, Center for Biomedical Engineering, Renal Division and Division of Infectious Diseases, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Harvard-Massachusetts Institute of Technology (MIT), Division of Health Sciences and Technology, Cambridge, MA 02139, USA
| | - Yuan Wan
- Department of Oncology, The Second Affiliated Hospital of Southeast University, Southeast University, Nanjing, Jiangsu 210003, PR China
- Ian Wark Research Institute, University of South Australia, Mawson Lakes, Adelaide, SA 5095, Australia
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Stimulation of human peripheral blood mononuclear cells by the sialic acid precursor N-propanoylmannosamine. Glycoconj J 2013; 30:813-8. [DOI: 10.1007/s10719-013-9485-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Revised: 05/23/2013] [Accepted: 06/17/2013] [Indexed: 01/08/2023]
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230
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Chu C, Celik E, Rico F, Moy VT. Elongated membrane tethers, individually anchored by high affinity α4β1/VCAM-1 complexes, are the quantal units of monocyte arrests. PLoS One 2013; 8:e64187. [PMID: 23691169 PMCID: PMC3656870 DOI: 10.1371/journal.pone.0064187] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Accepted: 04/12/2013] [Indexed: 11/18/2022] Open
Abstract
The α4β1 integrin facilitates both monocyte rolling and adhesion to the vascular endothelium and is physiologically activated by monocyte chemoattractant protein (MCP-1). The current study investigated the initial events in the adhesion of THP-1 cells to immobilized Vascular Cell Adhesion Molecule 1 (VCAM-1). Using AFM force measurements, cell adhesion was shown to be mediated by two populations of α4β1/VCAM-1 complexes. A low affinity form of α4β1 was anchored to the elastic elements of the cytoskeleton, while a higher affinity conformer was coupled to the viscous elements of the cell membrane. Within 100 ms of contact, THP-1 cells, stimulated by co-immobilized MCP-1, exhibited a tremendous increase in adhesion to VCAM-1. Enhanced cell adhesion was accompanied by a local decoupling of the cell membrane from the cytoskeleton and the formation of long membrane tethers. The tethers were individually anchored by multiple α4β1/VCAM-1 complexes that prolonged the extension of the viscous tethers. In vivo, the formation of these membrane tethers may provide the quantal structural units for the arrest of rolling monocytes within the blood vessels.
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Affiliation(s)
- Calvin Chu
- Department of Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, Florida, United States of America
| | - Emrah Celik
- Department of Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, Florida, United States of America
| | - Felix Rico
- Department of Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, Florida, United States of America
| | - Vincent T. Moy
- Department of Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, Florida, United States of America
- * E-mail:
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Abstract
PURPOSE OF REVIEW The leukocyte adhesion deficiency (LAD) syndromes are rare genetically determined conditions with challenging clinical features. These immunodeficiencies also provide insights that are broadly relevant to the biology of leukocytes, platelets, intercellular interactions, and intracellular signaling. Recent discoveries merit their review in the context of existing knowledge. RECENT FINDINGS New activities of β(2) integrins, which are deficient or absent in LAD-I, and new β(2) integrin-dependent functions of neutrophils and other leukocytes have recently been identified. Genetic defects and mechanisms accounting for impaired fucosylation of selectin ligands and defective selectin binding and signaling in LAD-II are now apparent. LAD-III, which presents with bleeding similar to that in Glanzmann thrombasthenia and platelet dysfunction in addition to impaired leukocyte adhesion, is now known to be due to absence of KINDLIN-3, a cytoplasmic protein that acts cooperatively with TALIN-1 in activating β(1), β(2), and β(3) integrins. Understanding of the leukocyte adhesion cascade and interactions of leukocytes with inflamed endothelium, which are impaired in each of the LAD syndromes, continues to be refined. SUMMARY Although LAD syndromes are rare maladies, their investigation is generating new knowledge directly applicable to the diagnosis and care of patients and to fundamental paradigms in immunobiology and hemostasis.
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232
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Herter J, Zarbock A. Integrin Regulation during Leukocyte Recruitment. THE JOURNAL OF IMMUNOLOGY 2013; 190:4451-7. [DOI: 10.4049/jimmunol.1203179] [Citation(s) in RCA: 143] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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233
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Daniel AE, van Buul JD. Endothelial junction regulation: a prerequisite for leukocytes crossing the vessel wall. J Innate Immun 2013; 5:324-35. [PMID: 23571667 DOI: 10.1159/000348828] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Accepted: 02/12/2013] [Indexed: 12/13/2022] Open
Abstract
The leukocytes of the innate immune system, especially neutrophils and monocytes, exit the circulation early in the response to local inflammation and infection. This is necessary to control and prevent the spread of infections before an adaptive immune response can be raised. The endothelial cells and the intercellular junctions that connect them form a barrier that leukocytes need to pass in order to get to the site of inflammation. The junctions are tightly regulated which ensures that leukocytes only exit when and where they are needed. This regulation is disturbed in many chronic inflammatory diseases which are characterized by ongoing recruitment and interstitial accumulation of leukocytes. In this review, we summarize the molecular mechanisms that regulate endothelial cell-cell junctions and prevent or permit leukocyte transendothelial migration.
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Affiliation(s)
- Anna E Daniel
- Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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234
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Tekin HC, Cornaglia M, Gijs MAM. Attomolar protein detection using a magnetic bead surface coverage assay. LAB ON A CHIP 2013; 13:1053-9. [PMID: 23392210 DOI: 10.1039/c3lc41285g] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We demonstrate a microfluidic method for ultra-sensitive protein detection in serum. First, 'large' (2.8 μm) antibody-functionalized magnetic beads specifically capture antigen from a serum matrix under active microfluidic mixing. Subsequently, the large beads loaded with the antigens are gently exposed to a surface pattern of fixed 'small' (1.0 μm) antibody-coated magnetic beads. During the exposure, attractive magnetic bead dipole-dipole interactions improve the contact between the two bead types and help the antigen-antibody immunocomplex formation, while non-specific large bead adsorption is limited by exploiting viscous drag forces in the microfluidic channel on the small-bead pattern. This efficient antigen-antibody recognition and binding mechanism mimics a biological process of selective recognition of tissue molecules, like is the case when leukocytes roll and slow down on blood vessel walls by selectin-mediated adhesion. After exposure of the large beads to the pattern of small beads, the antigen concentration is detected by simply counting the number of surface pattern-bound large magnetic beads. The new technique allows detection of proteins down to the sub-zeptomole range. In particular, we demonstrate detection of only 200 molecules of Tumor Necrosis Factor-α (TNF-α) in a serum sample volume of 5 μL, corresponding to a concentration of 60 attomolar or 1 fg mL(-1).
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Affiliation(s)
- H Cumhur Tekin
- Laboratory of Microsystems, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
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235
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Abstract
Quantitative dynamic footprinting (qDF) allows visualization of the footprints of live leukocytes rolling on a selectin-coated cover glass. qDF works on the principle of total internal reflection fluorescence, which involves fluorescence excitation in a thin slice (~200 nm) of the cell proximal to the cover glass while the rest of the cell remains dark. Dual color qDF (DqDF) is an advancement of qDF, which enables simultaneous visualization of two fluorochromes in the footprints of rolling leukocytes. When the fluorochrome is localized either in the cell cytoplasm or plasma membrane, the two-dimensional qDF image is used to create a three-dimensional rendition of the footprint topography. DqDF is a useful tool to study leukocyte adhesion under flow, and has recently been used to reveal mechanisms that enable neutrophils to roll at high shear stresses that prevail in venules during inflammation.
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Affiliation(s)
- Prithu Sundd
- Division of Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA 92037, USA
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236
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Zhang Y, Jiang N, Zarnitsyna VI, Klopocki AG, McEver RP, Zhu C. P-selectin glycoprotein ligand-1 forms dimeric interactions with E-selectin but monomeric interactions with L-selectin on cell surfaces. PLoS One 2013; 8:e57202. [PMID: 23451187 PMCID: PMC3581448 DOI: 10.1371/journal.pone.0057202] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Accepted: 01/18/2013] [Indexed: 11/19/2022] Open
Abstract
Interactions of selectins with cell surface glycoconjugates mediate the first step of the adhesion and signaling cascade that recruits circulating leukocytes to sites of infection or injury. P-selectin dimerizes on the surface of endothelial cells and forms dimeric bonds with P-selectin glycoprotein ligand-1 (PSGL-1), a homodimeric sialomucin on leukocytes. It is not known whether leukocyte L-selectin or endothelial cell E-selectin are monomeric or oligomeric. Here we used the micropipette technique to analyze two-dimensional binding of monomeric or dimeric L- and E-selectin with monomeric or dimeric PSGL-1. Adhesion frequency analysis demonstrated that E-selectin on human aortic endothelial cells supported dimeric interactions with dimeric PSGL-1 and monomeric interactions with monomeric PSGL-1. In contrast, L-selectin on human neutrophils supported monomeric interactions with dimeric or monomeric PSGL-1. Our work provides a new method to analyze oligomeric cross-junctional molecular binding at the interface of two interacting cells.
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Affiliation(s)
- Yan Zhang
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States of America
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237
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Xiao B, Tong C, Jia X, Guo R, Lü S, Zhang Y, McEver RP, Zhu C, Long M. Tyrosine replacement of PSGL-1 reduces association kinetics with P- and L-selectin on the cell membrane. Biophys J 2013; 103:777-85. [PMID: 22947939 DOI: 10.1016/j.bpj.2012.07.028] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 07/16/2012] [Accepted: 07/18/2012] [Indexed: 10/28/2022] Open
Abstract
Binding of selectins to P-selectin glycoprotein ligand-1 (PSGL-1) mediates tethering and rolling of leukocytes on the endothelium during inflammation. Previous measurements obtained with a flow-chamber assay have shown that mutations of three tyrosines at the PSGL-1 N-terminus (Y46, Y48, and Y51) increase the reverse rates and their sensitivity to the force of bonds with P- and L-selectin. However, the effects of these mutations on the binding affinities and forward rates have not been studied. We quantified these effects by using an adhesion frequency assay to measure two-dimensional affinity and kinetic rates at zero force. Wild-type PSGL-1 has 2.2- to 8.5-fold higher binding affinities for P- and L-selectin than PSGL-1 mutants with two of three tyrosines substituted by phenylalanines, and 9.6- to 49-fold higher affinities than the PSGL-1 mutant with all three tyrosines replaced. In descending order, the affinity decreased from wild-type to Y48/51F, Y46/51F, Y46/48F, and Y46/48/51F. The affinity differences were attributed to major changes in the forward rate and minor changes in the reverse rate, suggesting that these tyrosines regulate the accessibility of PSGL-1 to P- and L-selectin via electrostatic interactions, which is supported by molecular-dynamics simulations. Our results provide insights into the structure-function relationship of receptor-ligand binding at a single-residue level.
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Affiliation(s)
- Botao Xiao
- Key Laboratory of Microgravity, Institute of Mechanics, Chinese Academy of Sciences, Beijing, China
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238
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Ivetic A. Signals regulating L-selectin-dependent leucocyte adhesion and transmigration. Int J Biochem Cell Biol 2013; 45:550-5. [PMID: 23299028 DOI: 10.1016/j.biocel.2012.12.023] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Revised: 12/21/2012] [Accepted: 12/27/2012] [Indexed: 01/17/2023]
Abstract
L-selectin is a type I transmembrane cell adhesion molecule that is expressed on the surface of most circulating leukocytes. Studies in L-selectin knockout mice reveal a prominent role for this glycoprotein in health and disease, regulating leucocyte recruitment to peripheral lymph nodes (e.g. naïve T-cells) and sites of acute and chronic inflammation (e.g. monocytes and neutrophils). Clinical trials have revealed L-selectin as a promising target in some acute and chronic inflammatory diseases. Unearthing the intracellular signals that act directly downstream of L-selectin may also expose novel therapeutic targets in a cell type/disease-specific manner. This review will focus on L-selectin-dependent signalling - exploring the different signals that potentially arise from distinct phases of the multi-step adhesion cascade and the contribution of known binding partners of L-selectin in this response.
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Affiliation(s)
- Aleksandar Ivetic
- Membrane/Cytoskeleton Signalling Group, Cardiovascular Division, British Heart Foundation, Centre of Research Excellence, King's College London, London SE5 9NU, United Kingdom.
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239
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Scheibe C, Wedepohl S, Riese SB, Dernedde J, Seitz O. Carbohydrate-PNA and aptamer-PNA conjugates for the spatial screening of lectins and lectin assemblies. Chembiochem 2013; 14:236-50. [PMID: 23292704 DOI: 10.1002/cbic.201200618] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Indexed: 11/06/2022]
Abstract
Nucleic acid architectures offer intriguing opportunities for the interrogation of structural properties of protein receptors. In this study, we performed a DNA-programmed spatial screening to characterize two functionally distinct receptor systems: 1) structurally well-defined Ricinus communis agglutinin (RCA(120)), and 2) rather ill-defined assemblies of L-selectin on nanoparticles and leukocytes. A robust synthesis route that allowed the attachment both of carbohydrate ligands-such as N-acetyllactosamine (LacNAc), sialyl-Lewis-X (sLe(X)), and mannose-and of a DNA aptamer to PNAs was developed. A systematically assembled series of different PNA-DNA complexes served as multivalent scaffolds to control the spatial alignments of appended lectin ligands. The spatial screening of the binding sites of RCA(120) was in agreement with the crystal structure analysis. The study revealed that two appropriately presented LacNAc ligands suffice to provide unprecedented RCA(120) affinity (K(D) = 4 μM). In addition, a potential secondary binding site was identified. Less dramatic binding enhancements were obtained when the more flexible L-selectin assemblies were probed. This study involved the bivalent display both of the weak-affinity sLe(X) ligand and of a high-affinity DNA aptamer. Bivalent presentation led to rather modest (sixfold or less) enhancements of binding when the self-assemblies were targeted against L-selectin on gold nanoparticles. Spatial screening of L-selectin on the surfaces of leukocytes showed higher affinity enhancements (25-fold). This and the distance-activity relationships indicated that leukocytes permit dense clustering of L-selectin.
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Affiliation(s)
- Christian Scheibe
- Institut für Chemie, Humboldt Universität zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany
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240
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Sundd P, Pospieszalska MK, Ley K. Neutrophil rolling at high shear: flattening, catch bond behavior, tethers and slings. Mol Immunol 2012; 55:59-69. [PMID: 23141302 DOI: 10.1016/j.molimm.2012.10.025] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Revised: 10/15/2012] [Accepted: 10/16/2012] [Indexed: 12/30/2022]
Abstract
Neutrophil recruitment to sites of inflammation involves neutrophil rolling along the inflamed endothelium in the presence of shear stress imposed by blood flow. Neutrophil rolling in post-capillary venules in vivo is primarily mediated by P-selectin on the endothelium binding to P-selectin glycoprotein ligand-1 (PSGL-1) constitutively expressed on neutrophils. Blood flow exerts a hydrodynamic drag on the rolling neutrophil which is partially or fully balanced by the adhesive forces generated in the P-selectin-PSGL-1 bonds. Rolling is the result of rapid formation and dissociation of P-selectin-PSGL-1 bonds at the center and rear of the rolling cell, respectively. Neutrophils roll stably on P-selectin in post-capillary venules in vivo and flow chambers in vitro at wall shear stresses greater than 6 dyn cm(-2). However, the mechanisms that enable neutrophils to roll at such high shear stress are not completely understood. In vitro and in vivo studies have led to the discovery of four potential mechanisms, viz. cell flattening, catch bond behavior, membrane tethers, and slings. Rolling neutrophils undergo flattening at high shear stress, which not only increases the size of the cell footprint but also reduces the hydrodynamic drag experienced by the rolling cell. P-selectin-PSGL-1 bonds behave as catch bonds at small detachment forces and thus become stronger with increasing force. Neutrophils rolling at high shear stress form membrane tethers which can be longer than the cell diameter and promote the survival of P-selectin-PSGL-1 bonds. Finally, neutrophils rolling at high shear stress form 'slings', which act as cell autonomous adhesive substrates and support step-wise peeling. Tethers and slings act together and contribute to the forces balancing the hydrodynamic drag. How the synergy between the four mechanisms leads to stable rolling at high shear stress is an area that needs further investigation.
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Affiliation(s)
- Prithu Sundd
- Division of Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA 92037, USA
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241
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Nissinen L, Koivunen J, Käpylä J, Salmela M, Nieminen J, Jokinen J, Sipilä K, Pihlavisto M, Pentikäinen OT, Marjamäki A, Heino J. Novel α2β1 integrin inhibitors reveal that integrin binding to collagen under shear stress conditions does not require receptor preactivation. J Biol Chem 2012; 287:44694-702. [PMID: 23132859 DOI: 10.1074/jbc.m111.309450] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The interaction between α2β1 integrin (GPIa/IIa, VLA-2) and vascular collagen is one of the initiating events in thrombus formation. Here, we describe two structurally similar sulfonamide derivatives, BTT-3033 and BTT-3034, and show that, under static conditions, they have an almost identical effect on α2-expressing CHO cell adhesion to collagen I, but only BTT-3033 blocks platelet attachment under flow (90 dynes/cm(2)). Differential scanning fluorimetry showed that both molecules bind to the α2I domain of the recombinant α2 subunit. To further study integrin binding mechanism(s) of the two sulfonamides, we created an α2 Y285F mutant containing a substitution near the metal ion-dependent adhesion site motif in the α2I domain. The action of BTT-3033, unlike that of BTT-3034, was dependent on Tyr-285. In static conditions BTT-3034, but not BTT-3033, inhibited collagen binding by an α2 variant carrying a conformationally activating E318W mutation. Conversely, in under flow conditions (90 dynes/cm(2)) BTT-3033, but not BTT-3034, inhibited collagen binding by an α2 variant expressing E336A loss-of-function mutation. Thus, the binding sites for BTT-3033 and BTT-3034 are differentially available in distinct integrin conformations. Therefore, these sulfonamides can be used to study the biological role of different functional stages of α2β1. Furthermore, only the inhibitor that recognized the non-activated conformation of α2β1 integrin under shear stress conditions effectively blocked platelet adhesion, suggesting that the initial interaction between integrin and collagen takes place prior to receptor activation.
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242
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Park IS, Eom K, Son J, Chang WJ, Park K, Kwon T, Yoon DS, Bashir R, Lee SW. Microfluidic multifunctional probe array dielectrophoretic force spectroscopy with wide loading rates. ACS NANO 2012; 6:8665-8673. [PMID: 22967242 DOI: 10.1021/nn302202t] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The simultaneous investigation of a large number of events with different types of intermolecular interactions, from nonequilibrium high-force pulling assays to quasi-equilibrium unbinding events in the same environment, can be very important for fully understanding intermolecular bond-rupture mechanisms. Here, we describe a novel dielectrophoretic force spectroscopy technique that utilizes microsized beads as multifunctional probes for parallel measurement of intermolecular forces with an extremely wide range of force rate (10(-4) to 10(4) pN/s) inside a microfluidic device. In our experiments, various forces, which broadly form the basis of all molecular interactions, were measured across a range of force loading rates by multifunctional probes of various diameters with a throughput of over 600 events per mm(2), simultaneously and in the same environment. Furthermore, the individual bond-rupture forces, the parameters for the characterization of entire energy landscapes, and the effective stiffness of the force spectroscopy were determined on the basis of the measured results. This method of determining intermolecular forces could be very useful for the precise and simultaneous examination of various molecular interactions, as it can be easily and cost-effectively implemented within a microfluidic device for a range of applications including immunoassays, molecular mechanics, chemical and biological screening, and mechanobiology.
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Affiliation(s)
- In Soo Park
- Department of Biomedical Engineering, Yonsei University, Won-Ju, 220-710, Korea
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243
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Kruss S, Erpenbeck L, Schön MP, Spatz JP. Circular, nanostructured and biofunctionalized hydrogel microchannels for dynamic cell adhesion studies. LAB ON A CHIP 2012; 12:3285-9. [PMID: 22858992 PMCID: PMC3448975 DOI: 10.1039/c2lc40611j] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
We report on a method to fabricate biofunctionalized polyethylene glycol hydrogel microchannels with adjustable circular cross-sections. The inner channel surfaces are decorated with Au-nanoparticle arrays of tunable density. These Au-nanoparticles are functionalized with biomolecules whereas the hydrogel material provides an inert and biocompatible background. This technology provides control over flow conditions, channel curvature and biomolecule density on the channel surface. It can be applied for biophysical studies of cell-surface interactions mimicking, for example, leukocyte interactions with the endothelial lining in small vessels.
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Affiliation(s)
- Sebastian Kruss
- Department of New Materials and Biosystems, Max Planck Institute for Intelligent Systems, Heisenbergstr, Stuttgart, 370569, Germany.
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244
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Abstract
Integrins are a family of α/β heterodimeric adhesion metalloprotein receptors and their functions are highly dependent on and regulated by different divalent cations. Recently advanced studies have revolutionized our perception of integrin metal ion-binding sites and their specific functions. Ligand binding to integrins is bridged by a divalent cation bound at the MIDAS motif on top of either α I domain in I domain-containing integrins or β I domain in α I domain-less integrins. The MIDAS motif in β I domain is flanked by ADMIDAS and SyMBS, the other two crucial metal ion binding sites playing pivotal roles in the regulation of integrin affinity and bidirectional signaling across the plasma membrane. The β-propeller domain of α subunit contains three or four β-hairpin loop-like Ca(2+)-binding motifs that have essential roles in integrin biogenesis. The function of another Ca(2+)-binding motif located at the genu of α subunit remains elusive. Here, we provide an overview of the integrin metal ion-binding sites and discuss their roles in the regulation of integrin functions.
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Affiliation(s)
- Kun Zhang
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
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245
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Reasor DA, Mehrabadi M, Ku DN, Aidun CK. Determination of critical parameters in platelet margination. Ann Biomed Eng 2012; 41:238-49. [PMID: 22965639 DOI: 10.1007/s10439-012-0648-7] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Accepted: 08/23/2012] [Indexed: 11/28/2022]
Abstract
An investigation of margination dependence on hematocrit, platelet shape, and viscosity ratio of plasma to cytoplasm is presented. Whole blood is modeled as a suspension of deformable red blood cells (RBCs) and rigid platelets in a viscous liquid. The fluid phase is simulated using the lattice-Boltzmann method, the RBC membranes are modeled with a coarse-grained spectrin-link method, and the dynamics of rigid particles are updated using Newton's equations of motion for axisymmetric shapes. The results emphasize that an increase in hematocrit increases the rate of margination. The viscosity ratio between the interior cytoplasm and suspending fluid can considerably alter the rate of margination. The aspect ratio of surrogate platelet particles influences the rate of margination as well. Spherical particles tend to migrate more quickly than disks. Highly viscous or rigid RBCs slow down margination.
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Affiliation(s)
- Daniel A Reasor
- George W. Woodruff School of Mechanical Engineering, and The Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
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246
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Nascimento-Silva V, Rodrigues da Silva G, Moraes JA, Cyrino FZ, Seabra SH, Bouskela E, Almeida Guimarães J, Barja-Fidalgo C. A pro-inflammatory profile of endothelial cell in Lonomia obliqua envenomation. Toxicon 2012; 60:50-60. [PMID: 22779081 DOI: 10.1016/j.toxicon.2012.03.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Lonomia obliqua envenomation is characterized by intense local inflammatory reaction, which, dependent on the severity of the case, is followed by severe clinical manifestations related to hemorrhagic disorders that can lead to fatal outcome. These effects were imputed to several toxins present in L. obliqua venom, which are responsible for procoagulant, anticoagulant as well as antithrombotic activities, being also able to interfere with vascular cells functions. In this work, the intravital microscopy analysis show that after administration of low doses of L. obliqua venom (1-3 μg/ml) on hamster cheek pouch, there was no alterations neither on arterioles or venules caliber nor in the vascular permeability up to 30 min. However, after 10 min in contact with venom occurred a clear activation in the vascular bed, characterized by an increase in leukocyte rolling and adhesion on endothelium of hamster cheek pouch venules. A confocal analysis of vascular beds, confirmed these results showing an increase in endothelial E-selectin and VCAM-1 expression. The effects of L. obliqua venom on human endothelial cell (EC) in vitro were also investigated. The treatment of EC with venom (1-3 μg/ml) did not affect cell viability. However, at concentrations as low as 3 μg/ml of L. obliqua venom modifies actin cytoskeleton dynamics, and increases focal adhesion contacts, inducing stress fiber formation, focal adhesion kinase (FAK) phosphorylation and its subsequent association to actin. These effects are followed by the activation of NF-κB pathway, a critical signaling in several events associated to vascular inflammation. Accordingly, L. obliqua venom leads to a significant increase in COX-2, NOS-2, HO-1, MMP-2 and MMP-9 expression. Taken together the data show that, even at low concentrations, L. obliqua venom can activate endothelial cells, which assume a pro-inflammatory profile, contributing for local effects and probably also for systemic disturbances due to its ability to modulate the properties of the vascular system.
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Affiliation(s)
- Vany Nascimento-Silva
- Laboratory of Biochemistry and Cellular Pharmacology, IBRAG, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil
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247
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Akiyoshi B, Biggins S. Reconstituting the kinetochore–microtubule interface: what, why, and how. Chromosoma 2012; 121:235-50. [PMID: 22289864 DOI: 10.1007/s00412-012-0362-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Revised: 01/15/2012] [Accepted: 01/16/2012] [Indexed: 10/14/2022]
Abstract
The kinetochore is the proteinaceous complex that governs the movement of duplicated chromosomes by interacting with spindle microtubules during mitosis and meiosis. Faithful chromosome segregation requires that kinetochores form robust load-bearing attachments to the tips of dynamic spindle microtubules, correct microtubule attachment errors, and delay the onset of anaphase until all chromosomes have made proper attachments. To understand how this macromolecular machine operates to segregate duplicated chromosomes with exquisite accuracy, it is critical to reconstitute and study kinetochore–microtubule interactions in vitro using defined components. Here, we review the current status of reconstitution as well as recent progress in understanding the microtubule-binding functions of kinetochores in vivo.
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Affiliation(s)
- Bungo Akiyoshi
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK.
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248
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Hajishengallis G, Chavakis T. Endogenous modulators of inflammatory cell recruitment. Trends Immunol 2012; 34:1-6. [PMID: 22951309 DOI: 10.1016/j.it.2012.08.003] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Revised: 07/26/2012] [Accepted: 08/01/2012] [Indexed: 12/29/2022]
Abstract
Leukocyte recruitment is a central immune process. Multiple factors have been described to promote leukocyte infiltration into inflamed tissues, but only recently has evidence for endogenous negative modulators of this inflammatory process emerged. The discovery of several locally produced modulators has emerged into a new field of endogenous inhibitors of leukocyte extravasation. Recent findings from several inflammatory disease models show that tissues can self-regulate the recruitment of inflammatory cells, suggesting that local tissues may have a greater 'regulatory say' over the immune response than previously appreciated. Here, we propose that locally produced modulators of leukocyte recruitment may represent local homeostatic mechanisms that tissues and organs may have evolved for protection against the destructive potential of the immune system.
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Affiliation(s)
- George Hajishengallis
- Department of Microbiology, University of Pennsylvania, School of Dental Medicine, Philadelphia, PA, USA.
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249
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Yoon G, Na S, Eom K. Loading device effect on protein unfolding mechanics. J Chem Phys 2012; 137:025102. [DOI: 10.1063/1.4732798] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
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250
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Montresor A, Toffali L, Constantin G, Laudanna C. Chemokines and the signaling modules regulating integrin affinity. Front Immunol 2012; 3:127. [PMID: 22654882 PMCID: PMC3360201 DOI: 10.3389/fimmu.2012.00127] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Accepted: 05/03/2012] [Indexed: 01/05/2023] Open
Abstract
Integrin-mediated adhesion is a general concept referring to a series of adhesive phenomena including tethering–rolling, affinity, valency, and binding stabilization altogether controlling cell avidity (adhesiveness) for the substrate. Arrest chemokines modulate each aspect of integrin activation, although integrin affinity regulation has been recognized as the prominent event in rapid leukocyte arrest induced by chemokines. A variety of inside-out and outside-in signaling mechanisms have been related to the process of integrin-mediated adhesion in different cellular models, but only few of them have been clearly contextualized to rapid integrin affinity modulation by arrest chemokines in primary leukocytes. Complex signaling processes triggered by arrest chemokines and controlling leukocyte integrin activation have been described for ras-related rap and for rho-related small GTPases. We summarize the role of rap and rho small GTPases in the regulation of rapid integrin affinity in primary leukocytes and provide a modular view of these pro-adhesive signaling events. A potential, albeit still speculative, mechanism of rho-mediated regulation of cytoskeletal proteins controlling the last step of integrin activation is also discussed. We also discuss data suggesting a functional integration between the rho- and rap-modules of integrin activation. Finally we examine the universality of signaling mechanisms regulating integrin triggering by arrest chemokines.
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Affiliation(s)
- Alessio Montresor
- Division of General Pathology, Department of Pathology, University of Verona Verona, Italy
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