scholarly journals β2 Integrins—Multi-Functional Leukocyte Receptors in Health and Disease

2020 ◽  
Vol 21 (4) ◽  
pp. 1402 ◽  
Author(s):  
Monika Bednarczyk ◽  
Henner Stege ◽  
Stephan Grabbe ◽  
Matthias Bros
Keyword(s):  
Autoimmune Diseases ◽  
Leukocyte Adhesion ◽  
Tumor Development ◽  
Inherited Disease ◽  
Immune Functions ◽  
Α Subunit ◽  
Surface Receptors ◽  
Β2 Integrin ◽  
The Individual ◽  
Β2 Integrins

β2 integrins are heterodimeric surface receptors composed of a variable α (CD11a-CD11d) and a constant β (CD18) subunit and are specifically expressed by leukocytes. The α subunit defines the individual functional properties of the corresponding β2 integrin, but all β2 integrins show functional overlap. They mediate adhesion to other cells and to components of the extracellular matrix (ECM), orchestrate uptake of extracellular material like complement-opsonized pathogens, control cytoskeletal organization, and modulate cell signaling. This review aims to delineate the tremendous role of β2 integrins for immune functions as exemplified by the phenotype of LAD-I (leukocyte adhesion deficiency 1) patients that suffer from strong recurrent infections. These immune defects have been largely attributed to impaired migratory and phagocytic properties of polymorphonuclear granulocytes. The molecular base for this inherited disease is a functional impairment of β2 integrins due to mutations within the CD18 gene. LAD-I patients are also predisposed for autoimmune diseases. In agreement, polymorphisms within the CD11b gene have been associated with autoimmunity. Consequently, β2 integrins have received growing interest as targets in the treatment of autoimmune diseases. Moreover, β2 integrin activity on leukocytes has been implicated in tumor development.

scholarly journals Loss of the Rap1 effector RIAM results in leukocyte adhesion deficiency due to impaired β2 integrin function in mice

Blood ◽  
2015 ◽  
Vol 126 (25) ◽  
pp. 2704-2712 ◽  
Author(s):  
Sarah Klapproth ◽  
Markus Sperandio ◽  
Elaine M. Pinheiro ◽  
Monika Prünster ◽  
Oliver Soehnlein ◽  
...  
Keyword(s):  
Leukocyte Adhesion ◽  
Leukocyte Adhesion Deficiency ◽  
Independent Manner ◽  
Β2 Integrin ◽  
Key Points ◽  
Β2 Integrins

Key Points RIAM is an essential regulator of β2 integrins on leukocytes. Leukocyte α4β1 integrin is activated in a RIAM-independent manner.

scholarly journals LDL-receptor–related protein regulates β2-integrin–mediated leukocyte adhesion

Blood ◽  
2005 ◽  
Vol 105 (1) ◽  
pp. 170-177 ◽  
Author(s):  
Patricia P. E. M. Spijkers ◽  
Paula da Costa Martins ◽  
Erik Westein ◽  
Carl G. Gahmberg ◽  
Jaap J. Zwaginga ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Leukocyte Adhesion ◽  
Low Density Lipoprotein ◽  
Ldl Receptor ◽  
Density Lipoprotein ◽  
U937 Cells ◽  
Related Protein ◽  
Β2 Integrin ◽  
Adhesive Surface ◽  
Β2 Integrins

Abstract β2-Integrin clustering on activation is a key event in leukocyte adhesion to the endothelium during the inflammatory response. In the search for molecular mechanisms leading to this clustering, we have identified low-density lipoprotein (LDL) receptor–related protein (LRP) as a new partner for β2-integrins at the leukocyte surface. Immobilized recombinant LRP fragments served as an adhesive surface for blood-derived leukocytes and the U937 cell line. This adhesion was decreased up to 95% in the presence of antibodies against β2-integrins, pointing to these integrins as potential partners for LRP. Using purified proteins, LRP indeed associated with the αMβ2 complex and the αM and αL I-domains (Kd, app ≈ 0.5 μM). Immunoprecipitation experiments and confocal microscopy revealed that endogenously expressed LRP and αLβ2 colocalized in monocytes and U937 cells. Furthermore, activation of U937 cells resulted in clustering of αLβ2 and LRP to similar regions at the cell surface, indicating potential cooperation between both proteins. This was confirmed by the lack of αLβ2 clustering in U937 cells treated by antisense oligonucleotides to down-regulate LRP. In addition, the absence of LRP resulted in complete abrogation of β2-integrin–dependent adhesion to endothelial cells in a perfusion system, demonstrating the presence of a previously unrecognized link between LRP and leukocyte function.

scholarly journals Urokinase Receptor (CD87) Regulates Leukocyte Recruitment via β2 Integrins In Vivo

1998 ◽  
Vol 188 (6) ◽  
pp. 1029-1037 ◽  
Author(s):  
Andreas E. May ◽  
Sandip M. Kanse ◽  
Leif R. Lund ◽  
Roland H. Gisler ◽  
Beat A. Imhof ◽  
...  
Keyword(s):  
Leukocyte Adhesion ◽  
Close Association ◽  
Phosphatidyl Inositol ◽  
Urokinase Receptor ◽  
Β2 Integrin ◽  
And Migration ◽  
Deficient Mice ◽  
Β2 Integrins

The urokinase receptor (CD87; uPAR) is found in close association with β2 integrins on leukocytes. We studied the functional consequence of this association for leukocyte adhesion and migration. In vivo, the β2 integrin–dependent recruitment of leukocytes to the inflamed peritoneum of uPAR-deficient mice was significantly reduced as compared with wild-type animals. In vitro, β2 integrin–mediated adhesion of leukocytes to endothelium was lost upon removal of uPAR from the leukocyte surface by phosphatidyl-inositol–specific phospholipase C. Leukocyte adhesion was reconstituted when soluble intact uPAR, but not a truncated form lacking the uPA-binding domain, was allowed to reassociate with the cell surface. uPAR ligation with a monoclonal antibody induced adhesion of monocytic cells and neutrophils to vascular endothelium by six- to eightfold, whereas ligation with inactivated uPA significantly reduced cell-to-cell adhesion irrespective of the β2 integrin–stimulating pathway. These data indicate that β2 integrin–mediated leukocyte–endothelial cell interactions and recruitment to inflamed areas require the presence of uPAR and define a new phenotype for uPAR-deficient mice. Moreover, uPAR ligation differentially modulates leukocyte adhesion to endothelium and provides novel targets for therapeutic strategies in inflammation-related vascular pathologies.

scholarly journals Measuring the metabolic evolution of glioblastoma throughout tumor development, regression, and recurrence with hyperpolarized magnetic resonance

2021 ◽  
Author(s):  
Travis C Salzillo ◽  
Vimbai Mawoneke ◽  
Joseph Weygand ◽  
Akaanksh Shetty ◽  
Joy Gumin ◽  
...  
Keyword(s):  
Tumor Progression ◽  
Cancer Metabolism ◽  
Academic Research ◽  
Tumor Development ◽  
Metabolic Imaging ◽  
Therapeutic Monitoring ◽  
Improve Patient Survival ◽  
Conventional Mri ◽  
Hyperpolarized Mri ◽  
The Individual

Rapid diagnosis and therapeutic monitoring of aggressive diseases such as glioblastoma can improve patient survival by providing physicians the time to optimally deliver treatment. This research tested whether metabolic imaging with hyperpolarized MRI could detect changes in tumor progression faster than conventional anatomic MRI in patient-derived glioblastoma murine models. To capture the dynamic nature of cancer metabolism, hyperpolarized MRI, NMR spectroscopy, and immunohistochemistry were performed at several time-points during tumor development, regression, and recurrence. Hyperpolarized MRI detected significant changes of metabolism throughout tumor progression whereas conventional MRI was less sensitive. This was accompanied by aberrations in amino acid and phospholipid lipid metabolism and MCT1 expression. Hyperpolarized MRI can help address clinical challenges such as identifying malignant disease prior to aggressive growth, differentiating pseudoprogression from true progression, and predicting relapse. The individual evolution of these metabolic assays as well as their correlations with one another provides context for further academic research.

scholarly journals Leukocyte adhesion is governed by endolysosomal two pore channel 2 (TPC2)

2021 ◽  
Author(s):  
Jonas Goretzko ◽  
Nicole Heitzig ◽  
Katharina Thomas ◽  
Einar Kleinhans Krogsaeter ◽  
Johannes Nass ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Cell Surface ◽  
Leukocyte Adhesion ◽  
Leukocyte Recruitment ◽  
Pore Channel ◽  
Initial Contact ◽  
Surface Receptors ◽  
Endothelial Cell Surface ◽  
Late Endosomes ◽  
Endothelial Functions

In response to pro-inflammatory challenges including pathogenic attack and tissue damage, the endothelial cell surface is rearranged to present leukocyte-engaging cell surface receptors. The initial contact needed for leukocyte tethering and rolling is mediated via adhesion demand-driven exocytosis of Weibel-Palade bodies (WPB) that contain the leukocyte receptor P-selectin together with the stabilizing co-factor CD63. We found that diminished expression of the endolysosomal non-selective cation channel TPC2 or inhibition of TPC2-mediated Ca2+-release via trans-Ned 19 led to reduced endolysosomal Ca2+ efflux, and blocked transfer of CD63 from late endosomes/lysosomes (LEL) to WPB, and a concomitant loss of P-selectin on the endothelial cell surface. Accordingly, P-selectin-mediated leukocyte recruitment to trans-Ned 19-treated HUVEC under flow was significantly reduced without disturbing VWF exocytosis. Our findings establish the endolysosome-related TPC2 Ca2+ channel as a key element in the maintenance of proper endothelial functions and a potential pharmacological target in the control of inflammatory leukocyte recruitment.

scholarly journals Measuring the Metabolic Evolution of Glioblastoma throughout Tumor Development, Regression, and Recurrence with Hyperpolarized Magnetic Resonance

Cells ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2621
Author(s):  
Travis C. Salzillo ◽  
Vimbai Mawoneke ◽  
Joseph Weygand ◽  
Akaanksh Shetty ◽  
Joy Gumin ◽  
...  
Keyword(s):  
Tumor Progression ◽  
Cancer Metabolism ◽  
Academic Research ◽  
Tumor Development ◽  
Metabolic Imaging ◽  
Therapeutic Monitoring ◽  
Improve Patient Survival ◽  
Conventional Mri ◽  
Hyperpolarized Mri ◽  
The Individual

Rapid diagnosis and therapeutic monitoring of aggressive diseases such as glioblastoma can improve patient survival by providing physicians the time to optimally deliver treatment. This research tested whether metabolic imaging with hyperpolarized MRI could detect changes in tumor progression faster than conventional anatomic MRI in patient-derived glioblastoma murine models. To capture the dynamic nature of cancer metabolism, hyperpolarized MRI, NMR spectroscopy, and immunohistochemistry were performed at several time-points during tumor development, regression, and recurrence. Hyperpolarized MRI detected significant changes of metabolism throughout tumor progression whereas conventional MRI was less sensitive. This was accompanied by aberrations in amino acid and phospholipid lipid metabolism and MCT1 expression. Hyperpolarized MRI can help address clinical challenges such as identifying malignant disease prior to aggressive growth, differentiating pseudoprogression from true progression, and predicting relapse. The individual evolution of these metabolic assays as well as their correlations with one another provides context for further academic research.

scholarly journals Interleukin-1, Tumour Necrosis Factor and Treatment of the Septic Shock Syndrome

1992 ◽  
Vol 3 (suppl b) ◽  
pp. 11-19
Author(s):  
Charles A Dinarello
Keyword(s):  
Septic Shock ◽  
Tumour Necrosis Factor ◽  
Tumour Necrosis ◽  
Neutralizing Antibodies ◽  
Inflammatory Diseases ◽  
Leukocyte Adhesion ◽  
Interleukin 1 ◽  
Platelet Activating Factor ◽  
Surface Receptors ◽  
Necrosis Factor

Treating the septic shock syndrome with antibodies that block only endotoxin has its limitations. Other targets for treating septic shock include neutralizing antibodies to the complement fragment C5a, platelet activating factor antagonists and blockade of endothelial cell leukocyte adhesion molecules. Specific blockade of the pro-inflammatory cytokines interleukin-1 (IL-1) or tumour necrosis factor (TNF) reduces the morbidity and mortality associated with septic shock. Moreover, blocking IL-1 and TNF likely has uses in treating diseases other than septic shock. Use of neutralizing antibodies to TNF or IL-1 receptors has reduced the consequences of infection and inflammation, including lethal outcomes in animal models. The IL-1 receptor antagonist, a naturally occurring cytokine, blocks shock and death due to Escherichia coli as well as ameliorates a variety of inflammatory diseases. Soluble TNF and IL-1 surface receptors, which bind their respective cytokines. also ameliorate disease processes. Clinical trials are presently evaluating the safety and efficacy of anticytokine therapies either alone or in combination.

scholarly journals Differential attenuation of β2 integrin–dependent and –independent neutrophil migration by Ly6G ligation

2019 ◽  
Vol 3 (3) ◽  
pp. 256-267 ◽  
Author(s):  
Pierre Cunin ◽  
Pui Y. Lee ◽  
Edy Kim ◽  
Angela B. Schmider ◽  
Nathalie Cloutier ◽  
...  
Keyword(s):  
Interleukin 1 ◽  
Neutrophil Migration ◽  
Surface Protein ◽  
Joint Inflammation ◽  
Selective Inhibition ◽  
Β2 Integrin ◽  
Β2 Integrins ◽  
Neutrophil Surface

Abstract Antibody ligation of the murine neutrophil surface protein Ly6G disrupts neutrophil migration in some contexts but not others. We tested whether this variability reflected divergent dependence of neutrophil migration on β2 integrins, adhesion molecules that interact with Ly6G at the neutrophil surface. In integrin-dependent murine arthritis, Ly6G ligation attenuated joint inflammation, even though mice lacking Ly6G altogether developed arthritis normally. By contrast, Ly6G ligation had no impact on integrin-independent neutrophil migration into inflamed lung. In peritoneum, the role of β2 integrins varied with stimulus, proving dispensable for neutrophil entry in Escherichia coli peritonitis but contributory in interleukin 1 (IL-1)–mediated sterile peritonitis. Correspondingly, Ly6G ligation attenuated only IL-1 peritonitis, disrupting the molecular association between integrins and Ly6G and inducing cell-intrinsic blockade restricted to integrin-dependent migration. Consistent with this observation, Ly6G ligation impaired integrin-mediated postadhesion strengthening for neutrophils arresting on activated cremaster endothelium in vivo. Together, these findings identify selective inhibition of integrin-mediated neutrophil emigration through Ly6G ligation, highlighting the marked site and stimulus specificity of β2 integrin dependence in neutrophil migration.

Neutrophil activation via β2 integrins (CD11/CD18): Molecular mechanisms and clinical implications

2007 ◽  
Vol 98 (08) ◽  
pp. 262-273 ◽  
Author(s):  
Jürgen Schymeinsky ◽  
Attila Mócsai ◽  
Barbara Walzog
Keyword(s):  
Receptor Tyrosine Kinase ◽  
Acute Inflammation ◽  
Molecular Mechanisms ◽  
Inflammatory Diseases ◽  
Polymorphonuclear Neutrophils ◽  
Downstream Signaling ◽  
Β2 Integrin ◽  
Pmn Functions ◽  
Integrin Family ◽  
Β2 Integrins

SummaryPolymorphonuclear neutrophils (PMN) are key components of the innate immunity and their efficient recruitment to the sites of lesion is a prerequisite for acute inflammation. Signaling via adhesion molecules of the β2 integrin family (CD11/CD18) plays an essential role for PMN recruitment and activation during inflammation. In this review, we will focus on the non-receptor tyrosine kinase Syk, an important downstream signaling component of β2 integrins that is required for the control of different PMN functions including adhesion,migration and phagocytosis. The exploration of β2 integrin-mediated Syk activation provided not only novel insights into the control of PMN functions but also led to the identification of Syk as a new molecular target for therapeutic intervention during inflammatory diseases.

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