P-selectin binding to P-selectin glycoprotein ligand-1 induces an intermediate state of αMβ2 activation and acts cooperatively with extracellular stimuli to support maximal adhesion of human neutrophils

Abstract P-selectin glycoprotein ligand 1 (PSGL-1, CD162) and integrin αMβ2 (Mac-1, CD11bCD18) are leukocyte adhesion molecules essential for innate immunity and inflammation. The interaction of PSGL-1 with P-selectin (CD62P) mediates tethering, rolling, and weak adhesion of leukocytes, during which they become sufficiently activated in situ by locally released or displayed cytokines and chemoattractants for integrin-mediated firm adhesion. However, communication between P-selectin and the integrin, whether P-selectin can trigger β2-integrin activation, remains controversial. We found that P-selectin immunoglobulin chimera and PSGL-1 monoclonal antibodies (mAbs) increased adhesion of human neutrophils to immobilized, but not soluble, fibrinogen. This intermediate state of neutrophil adhesion was defined by moderate clustering of integrin αMβ2, no increase in CBRM1/5 (a mAb specific for the activation epitope on the αM subunit) recognition, and no increase in surface expression of αMβ2, whereas phorbol myristate acetate (PMA) induced extensive changes in these 3 parameters. Furthermore, platelet-activating factor or interleukin 8 acted in concert with P-selectin for further enhancing the activation of αMβ2. We thus propose a model in which P-selectin induces an intermediate state of integrin activation and then cooperates with other extracellular stimuli to support maximal adhesion of human neutrophils.

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A LAD-III syndrome is associated with defective expression of the Rap-1 activator CalDAG-GEFI in lymphocytes, neutrophils, and platelets

Journal of Experimental Medicine ◽

10.1084/jem.20070058 ◽

2007 ◽

Vol 204 (7) ◽

pp. 1571-1582 ◽

Cited By ~ 117

Author(s):

Ronit Pasvolsky ◽

Sara W. Feigelson ◽

Sara Sebnem Kilic ◽

Amos J. Simon ◽

Guy Tal-Lapidot ◽

...

Keyword(s):

T Lymphocytes ◽

Leukocyte Adhesion ◽

Splice Junction ◽

Integrin Activation ◽

Leukocyte Adhesion Deficiency ◽

Protein Levels ◽

Guanine Exchange Factor ◽

Β3 Integrin ◽

Inside Out

Leukocyte and platelet integrins rapidly alter their affinity and adhesiveness in response to various activation (inside-out) signals. A rare leukocyte adhesion deficiency (LAD), LAD-III, is associated with severe defects in leukocyte and platelet integrin activation. We report two new LAD cases in which lymphocytes, neutrophils, and platelets share severe defects in β1, β2, and β3 integrin activation. Patients were both homozygous for a splice junction mutation in their CalDAG-GEFI gene, which is a key Rap-1/2 guanine exchange factor (GEF). Both mRNA and protein levels of the GEF were diminished in LAD lymphocytes, neutrophils, and platelets. Consequently, LAD-III platelets failed to aggregate because of an impaired αIIbβ3 activation by key agonists. β2 integrins on LAD-III neutrophils were unable to mediate leukocyte arrest on TNFα-stimulated endothelium, despite normal selectin-mediated rolling. In situ subsecond activation of neutrophil β2 integrin adhesiveness by surface-bound chemoattractants and of primary T lymphocyte LFA-1 by the CXCL12 chemokine was abolished. Chemokine inside-out signals also failed to stimulate lymphocyte LFA-1 extension and high affinity epitopes. Chemokine-triggered VLA-4 adhesiveness in T lymphocytes was partially defective as well. These studies identify CalDAG-GEFI as a critical regulator of inside-out integrin activation in human T lymphocytes, neutrophils, and platelets.

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Rosiglitazone Influences the Expression of Leukocyte Adhesion Molecules and CD14 Receptor in Type 2 Diabetes Mellitus Patients

Physiological Research ◽

10.33549/physiolres.932791 ◽

2014 ◽

pp. S293-S298 ◽

Cited By ~ 2

Author(s):

T. ŠTULC ◽

H. SVOBODOVÁ ◽

Z. KRUPIČKOVÁ ◽

R. DOLEŽALOVÁ ◽

I. MARINOV ◽

...

Keyword(s):

Diabetes Mellitus ◽

Type 2 Diabetes ◽

Type 2 Diabetes Mellitus ◽

Adhesion Molecules ◽

Leukocyte Adhesion ◽

Surface Expression ◽

Receptor Expression ◽

Rosiglitazone Treatment ◽

Leukocyte Adhesion Molecules

Diabetes mellitus is associated with increased inflammatory response, which may contribute to atherosclerosis progression. Experimental results demonstrated anti-inflammatory activity of glitazones; their effect on leukocyte adhesion molecules has not been studied to date. We therefore studied the effect of rosiglitazone treatment on leukocyte surface expression of adhesion molecules in patients with type 2 diabetes mellitus and compared our results with findings in healthy subjects. 33 subjects with type 2 diabetes and 32 healthy controls were included; patients were examined at baseline and after 5 months of rosiglitazone treatment (4 mg/d). Leukocyte expression of adhesion molecules LFA-1, CD18 and ICAM-1 was quantified using flow cytometry; in addition, CD14 (lipopolysaccharide receptor) expression was analyzed as a marker of nonspecific immunity. The expression of examined molecules at baseline was higher in patients compared to controls. Despite only mild decrease in blood glucose, rosiglitazone treatment induced substantial decrease of CD18 and CD14 expression and borderline decrease of LFA-1 and ICAM-1 expression (on monocytes only). We thus observed improvement in the expression of leukocyte inflammatory markers after rosiglitazone treatment. This effect is supposed to be mediated by direct effect of rosiglitazone on PPAR-γ receptors on leukocytes.

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Amantadine inhibits platelet-activating factor induced clathrin-mediated endocytosis in human neutrophils

AJP Cell Physiology ◽

10.1152/ajpcell.00416.2008 ◽

2009 ◽

Vol 297 (4) ◽

pp. C886-C897 ◽

Cited By ~ 12

Author(s):

Phillip C. Eckels ◽

Anirban Banerjee ◽

Ernest E. Moore ◽

Nathan J. D. McLaughlin ◽

Lynn M. Gries ◽

...

Keyword(s):

Shape Change ◽

Platelet Activating Factor ◽

Resonance Energy Transfer ◽

Resonance Energy ◽

Surface Expression ◽

Cytosolic Calcium ◽

Polymorphonuclear Neutrophils ◽

Organ Injury ◽

Calcium Flux ◽

Human Neutrophils

Receptor signaling is integral for adhesion, emigration, phagocytosis, and reactive oxygen species production in polymorphonuclear neutrophils (PMNs). Priming is an important part of PMN emigration, but it can also lead to PMN-mediated organ injury in the host. Platelet-activating factor (PAF) primes PMNs through activation of a specific G protein-coupled receptor. We hypothesize that PAF priming of PMNs requires clathrin-mediated endocytosis (CME) of the PAF receptor (PAFr), and, therefore, amantadine, known to inhibit CME, significantly antagonizes PAF signaling. PMNs were isolated by standard techniques to >98% purity and tested for viability. Amantadine (1 mM) significantly inhibited the PAF-mediated changes in the cellular distribution of clathrin and the physical colocalization [fluorescence resonance energy transfer positive (FRET+)] of early endosome antigen-1 and Rab5a, known components of CME and similar to hypertonic saline, a known inhibitor of CME. Furthermore, amantadine had no effect on the PAF-induced cytosolic calcium flux; however, phosphorylation of p38 MAPK was significantly decreased. Amantadine inhibited PAF-mediated changes in PMN physiology, including priming of the NADPH oxidase and shape change with lesser inhibition of increases in CD11b surface expression and elastase release. Furthermore, rimantadine, an amantadine analog, was a more potent inhibitor of PAF priming of the N-formyl-methionyl-leucyl-phenylalanine-activated oxidase. PAF priming of PMNs requires clathrin-mediated endocytosis that is inhibited when PMNs are pretreated with either amantadine or rimantadine. Thus, amantadine and rimantadine have the potential to ameliorate PMN-mediated tissue damage in humans.

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A novel genetic leukocyte adhesion deficiency in subsecond triggering of integrin avidity by endothelial chemokines results in impaired leukocyte arrest on vascular endothelium under shear flow

Blood ◽

10.1182/blood-2002-11-3427 ◽

2003 ◽

Vol 101 (11) ◽

pp. 4437-4445 ◽

Cited By ~ 57

Author(s):

Ronen Alon ◽

Memet Aker ◽

Sara Feigelson ◽

Maya Sokolovsky-Eisenberg ◽

Donald E. Staunton ◽

...

Keyword(s):

Shear Flow ◽

Vascular Endothelium ◽

Leukocyte Adhesion ◽

Genetic Disorder ◽

High Avidity ◽

Bleeding Tendency ◽

Integrin Activation ◽

Multistep Process ◽

Β2 Integrins

Abstract Leukocyte arrest on vascular endothelium under disruptive shear flow is a multistep process that requires in situ integrin activation on the leukocyte surface by endothelium-displayed chemoattractants, primarily chemokines. A genetic deficiency of leukocyte adhesion to endothelium associated with defective β2 integrin expression or function (LAD-1) has been described. We now report a novel severe genetic disorder in this multistep process associated with functional defects in multiple leukocyte integrins, reflected in recurrent infections, profound leukocytosis, and a bleeding tendency. This syndrome is associated with an impaired ability of neutrophil and lymphocyte β1 and β2 integrins to generate high avidity to their endothelial ligands and arrest cells on vascular endothelium in response to endothelial chemoattractant signals. Patient leukocytes roll normally on endothelial selectins, express intact integrins and G protein–coupled chemokine receptors (GPCR), spread on integrin ligands, and migrate normally along a chemotactic gradient. Activation of β2 integrins in response to GPCR signals and intrinsic soluble ligand binding properties of the very late activation antigen-4 (VLA-4) integrin are also retained in patient leukocytes. Nevertheless, all integrins fail to generate firm adhesion to immobilized ligands in response to in situ GPCR-mediated activation by chemokines or chemoattractants, a result of a primary defect in integrin rearrangement at ligand-bearing contacts. This syndrome is the first example of a human integrin-activation deficiency associated with defective GPCR stimulation of integrin avidity at subsecond contacts, a key step in leukocyte arrest on vascular endothelium under shear flow.

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