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Biomechanics of Neutrophil Tethers. Life (Basel) 2021; 11:life11060515. [PMID: 34073130 PMCID: PMC8230032 DOI: 10.3390/life11060515] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 05/22/2021] [Accepted: 05/25/2021] [Indexed: 12/11/2022] Open
Abstract
Leukocytes, including neutrophils, propelled by blood flow, can roll on inflamed endothelium using transient bonds between selectins and their ligands, and integrins and their ligands. When such receptor–ligand bonds last long enough, the leukocyte microvilli become extended and eventually form thin, 20 µm long tethers. Tether formation can be observed in blood vessels in vivo and in microfluidic flow chambers. Tethers can also be extracted using micropipette aspiration, biomembrane force probe, optical trap, or atomic force microscopy approaches. Here, we review the biomechanical properties of leukocyte tethers as gleaned from such measurements and discuss the advantages and disadvantages of each approach. We also review and discuss viscoelastic models that describe the dependence of tether formation on time, force, rate of loading, and cell activation. We close by emphasizing the need to combine experimental observations with quantitative models and computer simulations to understand how tether formation is affected by membrane tension, membrane reservoir, and interactions of the membrane with the cytoskeleton.
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Thromboinflammation Model-on-A-Chip by Whole Blood Microfluidics on Fixed Human Endothelium. Diagnostics (Basel) 2021; 11:diagnostics11020203. [PMID: 33573079 PMCID: PMC7911484 DOI: 10.3390/diagnostics11020203] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 12/23/2020] [Accepted: 01/26/2021] [Indexed: 01/15/2023] Open
Abstract
Microfluidic devices have an established role in the study of platelets and coagulation factors in thrombosis, with potential diagnostic applications. However, few microfluidic devices have assessed the contribution of neutrophils to thrombus formation, despite increasing knowledge of neutrophils’ importance in cardiovascular thrombosis. We describe a thromboinflammation model which uses straight channels, lined with fixed human umbilical vein endothelial cells, after treatment with tumour necrosis factor-alpha. Re-calcified whole blood is perfused over the endothelium at venous and arterial shear rate. Neutrophil adhesion, platelet and fibrin thrombus formation, is measured over time by the addition of fluorescent antibodies to a whole blood sample. Fixed endothelium retains surface expression of adhesion molecules ICAM-1 and E-Selectin. Neutrophils adhere preferentially to platelet thrombi on the endothelium. Inhibitors of neutrophil adhesion and anti-inflammatory agents, such as isoquercetin, decrease neutrophil adhesion. Our model offers the advantage of the use of (1) fixed endothelium, (2) whole blood, instead of isolated neutrophils, and (3) a small amount of blood (1 mL). The characteristics of this thromboinflammation model provide the potential for further development for drug screening and point-of-care applications.
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Zhou W, Hsu AY, Wang Y, Syahirah R, Wang T, Jeffries J, Wang X, Mohammad H, Seleem MN, Umulis D, Deng Q. Mitofusin 2 regulates neutrophil adhesive migration and the actin cytoskeleton. J Cell Sci 2020; 133:jcs248880. [PMID: 32788232 PMCID: PMC7491649 DOI: 10.1242/jcs.248880] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 07/29/2020] [Indexed: 12/11/2022] Open
Abstract
Neutrophils rely on glycolysis for energy production. How mitochondria regulate neutrophil function is not fully understood. Here, we report that mitochondrial outer membrane protein Mitofusin 2 (MFN2) regulates neutrophil homeostasis and chemotaxis in vivoMfn2-deficient neutrophils are released from the hematopoietic tissue, trapped in the vasculature in zebrafish embryos, and not capable of chemotaxis. Consistent with this, human neutrophil-like cells that are deficient for MFN2 fail to arrest on activated endothelium under sheer stress or perform chemotaxis on 2D surfaces. Deletion of MFN2 results in a significant reduction of neutrophil infiltration to the inflamed peritoneal cavity in mice. Mechanistically, MFN2-deficient neutrophil-like cells display disrupted mitochondria-ER interaction, heightened intracellular Ca2+ levels and elevated Rac activation after chemokine stimulation. Restoring a mitochondria-ER tether rescues the abnormal Ca2+ levels, Rac hyperactivation and chemotaxis defect resulting from MFN2 depletion. Finally, inhibition of Rac activation restores chemotaxis in MFN2-deficient neutrophils. Taken together, we have identified that MFN2 regulates neutrophil migration via maintaining the mitochondria-ER interaction to suppress Rac activation, and uncovered a previously unrecognized role of MFN2 in regulating cell migration and the actin cytoskeleton.This article has an associated First Person interview with the first authors of the paper.
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Affiliation(s)
- Wenqing Zhou
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Alan Y Hsu
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Yueyang Wang
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Ramizah Syahirah
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Tianqi Wang
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Jacob Jeffries
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Xu Wang
- Department of Agricultural & Biological Engineering, Purdue University, West Lafayette, IN 47907, USA
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Haroon Mohammad
- Department of Comparative Pathobiology, Purdue University, West Lafayette, IN 47907, USA
| | - Mohamed N Seleem
- Department of Comparative Pathobiology, Purdue University, West Lafayette, IN 47907, USA
- Purdue Institute for Inflammation, Immunology & Infectious Disease, Purdue University, West Lafayette, IN 47907, USA
| | - David Umulis
- Department of Agricultural & Biological Engineering, Purdue University, West Lafayette, IN 47907, USA
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Qing Deng
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
- Purdue Institute for Inflammation, Immunology & Infectious Disease, Purdue University, West Lafayette, IN 47907, USA
- Purdue University Center for Cancer Research, Purdue University, West Lafayette, IN 47907, USA
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Martínez-Burgo B, Cobb SL, Pohl E, Kashanin D, Paul T, Kirby JA, Sheerin NS, Ali S. A C-terminal CXCL8 peptide based on chemokine-glycosaminoglycan interactions reduces neutrophil adhesion and migration during inflammation. Immunology 2019; 157:173-184. [PMID: 31013364 DOI: 10.1111/imm.13063] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 03/27/2019] [Accepted: 04/05/2019] [Indexed: 12/15/2022] Open
Abstract
Leucocyte recruitment is critical during many acute and chronic inflammatory diseases. Chemokines are key mediators of leucocyte recruitment during the inflammatory response, by signalling through specific chemokine G-protein-coupled receptors (GPCRs). In addition, chemokines interact with cell-surface glycosaminoglycans (GAGs) to generate a chemotactic gradient. The chemokine interleukin-8/CXCL8, a prototypical neutrophil chemoattractant, is characterized by a long, highly positively charged GAG-binding C-terminal region, absent in most other chemokines. To examine whether the CXCL8 C-terminal peptide has a modulatory role in GAG binding during neutrophil recruitment, we synthesized the wild-type CXCL8 C-terminal [CXCL8 (54-72)] (Peptide 1), a peptide with a substitution of glutamic acid (E) 70 with lysine (K) (Peptide 2) to increase positive charge; and also, a scrambled sequence peptide (Peptide 3). Surface plasmon resonance showed that Peptide 1, corresponding to the core CXCL8 GAG-binding region, binds to GAG but Peptide 2 binding was detected at lower concentrations. In the absence of cellular GAG, the peptides did not affect CXCL8-induced calcium signalling or neutrophil chemotaxis along a diffusion gradient, suggesting no effect on GPCR binding. All peptides equally inhibited neutrophil adhesion to endothelial cells under physiological flow conditions. Peptide 2, with its greater positive charge and binding to polyanionic GAG, inhibited CXCL8-induced neutrophil transendothelial migration. Our studies suggest that the E70K CXCL8 peptide, may serve as a lead molecule for further development of therapeutic inhibitors of neutrophil-mediated inflammation based on modulation of chemokine-GAG binding.
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Affiliation(s)
- Beatriz Martínez-Burgo
- Applied Immunobiology and Transplantation Research Group, Institute of Cellular Medicine, Medical School, Newcastle University, Newcastle upon Tyne, UK.,Newcastle NIHR Biomedical Research Centre, Newcastle upon Tyne, UK
| | | | - Ehmke Pohl
- Chemistry Department, Durham University, Durham, UK
| | | | | | - John A Kirby
- Applied Immunobiology and Transplantation Research Group, Institute of Cellular Medicine, Medical School, Newcastle University, Newcastle upon Tyne, UK.,Newcastle NIHR Biomedical Research Centre, Newcastle upon Tyne, UK
| | - Neil S Sheerin
- Applied Immunobiology and Transplantation Research Group, Institute of Cellular Medicine, Medical School, Newcastle University, Newcastle upon Tyne, UK.,Newcastle NIHR Biomedical Research Centre, Newcastle upon Tyne, UK
| | - Simi Ali
- Applied Immunobiology and Transplantation Research Group, Institute of Cellular Medicine, Medical School, Newcastle University, Newcastle upon Tyne, UK.,Newcastle NIHR Biomedical Research Centre, Newcastle upon Tyne, UK
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Becker E, Schramm S, Binder MT, Allner C, Wiendl M, Neufert C, Atreya I, Neurath M, Zundler S. Dynamic Adhesion Assay for the Functional Analysis of Anti-adhesion Therapies in Inflammatory Bowel Disease. J Vis Exp 2018. [PMID: 30295649 DOI: 10.3791/58210] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Gut homing of immune cells is important for the pathogenesis of inflammatory bowel diseases (IBD). Integrin-dependent cell adhesion to addressins is a crucial step in this process and therapeutic strategies interfering with adhesion have been successfully established. The anti-α4β7 integrin antibody, vedolizumab, is used for the clinical treatment of Crohn's disease (CD) and ulcerative colitis (UC) and further compounds are likely to follow. The details of the adhesion procedure and the action mechanisms of anti-integrin antibodies are still unclear in many regards due to the limited available techniques for the functional research in this field. Here, we present a dynamic adhesion assay for the functional analysis of human cell adhesion under flow conditions and the impact of anti-integrin therapies in the context of IBD. It is based on the perfusion of primary human cells through addressin-coated ultrathin glass capillaries with real-time microscopic analysis. The assay offers a variety of opportunities for refinements and modifications and holds potentials for mechanistic discoveries and translational applications.
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Affiliation(s)
- Emily Becker
- Department of Medicine 1, University of Erlangen-Nuremberg
| | | | | | | | | | | | - Imke Atreya
- Department of Medicine 1, University of Erlangen-Nuremberg
| | - Markus Neurath
- Department of Medicine 1, University of Erlangen-Nuremberg
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Erbeldinger N, Rapp F, Ktitareva S, Wendel P, Bothe AS, Dettmering T, Durante M, Friedrich T, Bertulat B, Meyer S, Cardoso MC, Hehlgans S, Rödel F, Fournier C. Measuring Leukocyte Adhesion to (Primary) Endothelial Cells after Photon and Charged Particle Exposure with a Dedicated Laminar Flow Chamber. Front Immunol 2017; 8:627. [PMID: 28620384 PMCID: PMC5451490 DOI: 10.3389/fimmu.2017.00627] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 05/11/2017] [Indexed: 12/12/2022] Open
Abstract
The vascular endothelium interacts with all types of blood cells and is a key modulator of local and systemic inflammatory processes, for example, in the adhesion of blood leukocytes to endothelial cells (EC) and the following extravasation into the injured tissue. The endothelium is constantly exposed to mechanical forces caused by blood flow, and the resulting shear stress is essential for the maintenance of endothelial function. Changes in local hemodynamics are sensed by EC, leading to acute or persistent changes. Therefore, in vitro assessment of EC functionality should include shear stress as an essential parameter. Parallel-plate flow chambers with adjustable shear stress can be used to study EC properties. However, commercially available systems are not suitable for radiation experiments, especially with charged particles, which are increasingly used in radiotherapy of tumors. Therefore, research on charged-particle-induced vascular side effects is needed. In addition, α-particle emitters (e.g., radon) are used to treat inflammatory diseases at low doses. In the present study, we established a flow chamber system, applicable for the investigation of radiation induced changes in the adhesion of lymphocytes to EC as readout for the onset of an inflammatory reaction or the modification of a pre-existing inflammatory state. In this system, primary human EC are cultured under physiological laminar shear stress, subjected to a proinflammatory treatment and/or irradiation with X-rays or charged particles, followed by a coincubation with primary human lymphocytes (peripheral blood lymphocytes (PBL)). Analysis is performed by semiautomated quantification of fluorescent staining in microscopic pictures. First results obtained after irradiation with X-rays or helium ions indicate decreased adhesion of PBL to EC under laminar conditions for both radiation qualities, whereas adhesion of PBL under static conditions is not clearly affected by irradiation. Under static conditions, no radiation-induced changes in surface expression of adhesion molecules and activation of nuclear factor kappa B (NF-κB) signaling were observed after single cell-based high-throughput analysis. In subsequent studies, these investigations will be extended to laminar conditions.
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Affiliation(s)
- Nadine Erbeldinger
- Department of Biophysics, GSI Helmholtz Center for Heavy Ion Research, Darmstadt, Germany.,Department of Biology, Technical University Darmstadt, Darmstadt, Germany
| | - Felicitas Rapp
- Department of Biophysics, GSI Helmholtz Center for Heavy Ion Research, Darmstadt, Germany
| | - Svetlana Ktitareva
- Department of Biophysics, GSI Helmholtz Center for Heavy Ion Research, Darmstadt, Germany
| | - Philipp Wendel
- Department of Biophysics, GSI Helmholtz Center for Heavy Ion Research, Darmstadt, Germany
| | - Anna S Bothe
- Department of Biophysics, GSI Helmholtz Center for Heavy Ion Research, Darmstadt, Germany
| | - Till Dettmering
- Department of Biophysics, GSI Helmholtz Center for Heavy Ion Research, Darmstadt, Germany
| | - Marco Durante
- Department of Biophysics, GSI Helmholtz Center for Heavy Ion Research, Darmstadt, Germany
| | - Thomas Friedrich
- Department of Biophysics, GSI Helmholtz Center for Heavy Ion Research, Darmstadt, Germany
| | - Bianca Bertulat
- Department of Biology, Technical University Darmstadt, Darmstadt, Germany
| | - Stephanie Meyer
- Department of Biology, Technical University Darmstadt, Darmstadt, Germany
| | - M C Cardoso
- Department of Biology, Technical University Darmstadt, Darmstadt, Germany
| | - Stephanie Hehlgans
- Department of Radiotherapy and Oncology, University of Frankfurt, Frankfurt, Germany
| | - Franz Rödel
- Department of Radiotherapy and Oncology, University of Frankfurt, Frankfurt, Germany
| | - Claudia Fournier
- Department of Biophysics, GSI Helmholtz Center for Heavy Ion Research, Darmstadt, Germany
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MnTBAP increases BMPR-II expression in endothelial cells and attenuates vascular inflammation. Vascul Pharmacol 2016; 84:67-73. [PMID: 27401963 DOI: 10.1016/j.vph.2016.07.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Revised: 05/03/2016] [Accepted: 07/01/2016] [Indexed: 11/21/2022]
Abstract
AIMS The endothelium plays an important role during vascular inflammation. Previous data have demonstrated a high expression level of manganese-superoxide dismutase (MnSOD) in endothelial cells and suggested an important role of MnSOD in several cardiovascular diseases. Manganese (III) tetrakis (4-benzoic acid) porphyrin (MnTBAP) has been shown to mimic some of the effects of MnSOD and prevented the development of diabetes and obesity. However, its effect on vascular inflammation and the underlying mechanism is still unknown. METHODS AND RESULTS Leukocyte adhesion was evaluated in-vivo and in-vitro using dynamic flow chamber and intravital microscopy in mice. Expression of adhesion molecules induced by TNFα and adhesion of leukocytes to the vessel wall were inhibited by MnTBAP. The anti-inflammatory effect of MnTBAP was partly mediated by up-regulation of the BMPR-II and Smad dependent pathway. Additionally, MnTBAP decelerated the turn-over of endogenous BMPR-II. CONCLUSION Our data demonstrate that MnTBAP activates Smad signaling, preserves the turn-over of BMPR-II and elicits anti-inflammatory effects in endothelial cells, partly mediated by BMPR-II. This finding suggests a potential therapeutic impact of MnTBAP in the treatment of vascular inflammation.
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