scholarly journals CD16b associates with high-density, detergent-resistant membranes in human neutrophils

2005 ◽  
Vol 393 (1) ◽  
pp. 351-359 ◽  
Author(s):  
Maria J. G. Fernandes ◽  
Emmanuelle Rollet-Labelle ◽  
Guillaume Paré ◽  
Sébastien Marois ◽  
Marie-Lisane Tremblay ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Plasma Membrane ◽  
Direct Evidence ◽  
Cellular Responses ◽  
High Density ◽  
Polymorphonuclear Neutrophils ◽  
Human Neutrophils ◽  
Glycosylphosphatidylinositol Anchor ◽  
Detergent Resistant Membranes ◽  
Receptor Ligation

CD16b is unique in that it is the only Fc receptor linked to the plasma membrane by a GPI (glycosylphosphatidylinositol) anchor. GPI-anchored proteins often preferentially localize to DRMs (detergent-resistant membranes) that are rich in sphingolipids and cholesterol and play an important role in signal transduction. Even though the responses to CD16b engagement have been intensively investigated, the importance of DRM integrity for CD16b signalling has not been characterized in human neutrophils. We provide direct evidence that CD16b constitutively partitions with both low- and high-density DRMs. Moreover, upon CD16b engagement, a significant increase in the amount of the receptor is observed in high-density DRMs. Similarly to CD16b, CD11b also resides in low- and high-density DRMs. In contrast with CD16b, the partitioning of CD11b in DRMs does not change in response to CD16b engagement. We also provide evidence for the implication of Syk in CD16b signalling and its partitioning to DRMs in resting and activated PMNs (polymorphonuclear neutrophils). Additionally, DRM-disrupting agents, such as nystatin and methyl-β-cyclodextrin, alter cellular responses to CD16b receptor ligation. Notably, a significant increase in the mobilization of intracellular Ca2+ and in tyrosine phosphorylation of intracellular substrates after CD16b engagement is observed. Altogether, the results of this study provide evidence that high-density DRMs play a role in CD16b signalling in human neutrophils.

scholarly journals Recruitment of the cross-linked opsonic receptor CD32A (FcγRIIA) to high-density detergent-resistant membrane domains in human neutrophils

2004 ◽  
Vol 381 (3) ◽  
pp. 919-928 ◽  
Author(s):  
Emmanuelle ROLLET-LABELLE ◽  
Sébastien MAROIS ◽  
Kathy BARBEAU ◽  
Stephen E. MALAWISTA ◽  
Paul H. NACCACHE
Keyword(s):  
Tyrosine Phosphorylation ◽  
Plasma Membranes ◽  
Kinase Inhibitor ◽  
Src Kinase ◽  
High Density ◽  
Human Neutrophils ◽  
Cross Linking ◽  
Src Kinases ◽  
Membrane Domains ◽  
Detergent Resistant Membranes

We have previously shown that CD32A (or FcγRIIA), one of the main opsonin receptors, was rapidly insolubilized and degraded in intact neutrophils after its cross-linking. In view of these experimental difficulties, the early signalling steps in response to CD32A activation were studied in purified plasma membranes of neutrophils. After CD32A cross-linking in these fractions, the tyrosine phosphorylation of two major substrates, the receptor itself and the tyrosine kinase Syk, was observed. Phosphorylation of these two proteins was observed only in the presence of orthovanadate, indicating the presence, in the membranes, of one or more tyrosine phosphatases that maintain CD32A dephosphorylation. The tyrosine phosphorylation of these two proteins was inhibited by the Src kinase inhibitor, 4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine (PP2). The ligation of CD32A led to its recruitment to a previously uncharacterized subset of high-density flotillin-1-positive DRMs (detergent-resistant membranes). The changes in the solubility properties of CD32A were observed in the absence of added ATP; therefore, they were probably not secondary to the tyrosine phosphorylation of the receptor, rather they preceded it. Src kinases as well as Syk were constitutively present in DRMs of high and low density and no evident changes in their distribution were detected after cross-linking of CD32A. Pretreatment of plasma membranes with methyl-β-cyclodextrin did not inhibit the recruitment of CD32A to DRMs, although it led to the loss of the Src kinase Lyn from these fractions. In addition, methyl-β-cyclodextrin inhibited the tyrosine phosphorylation of CD32A and Syk induced by cross-linking of CD32A. This membrane model allowed us to observe a movement of CD32A from detergent-soluble regions of the membranes to DRMs, where it joined Src kinases and Syk and became tyrosine-phosphorylated.

The Signaling Pathways in Nitric Oxide Production by Neutrophils Exposed to N-nitrosodimethylamine

2018 ◽  
Vol 16 (2) ◽  
pp. 194-199
Author(s):  
Wioletta Ratajczak-Wrona ◽  
Ewa Jablonska
Keyword(s):  
Nitric Oxide ◽  
Signaling Pathways ◽  
Molecular Mechanisms ◽  
Polymorphonuclear Neutrophils ◽  
Microbial Pathogens ◽  
Human Neutrophils ◽  
No Production ◽  
Oxide Synthase ◽  
Inducible Nitric Oxide

Background: Polymorphonuclear neutrophils (PMNs) play a crucial role in the innate immune system’s response to microbial pathogens through the release of reactive nitrogen species, including Nitric Oxide (NO). </P><P> Methods: In neutrophils, NO is produced by the inducible Nitric Oxide Synthase (iNOS), which is regulated by various signaling pathways and transcription factors. N-nitrosodimethylamine (NDMA), a potential human carcinogen, affects immune cells. NDMA plays a major part in the growing incidence of cancers. Thanks to the increasing knowledge on the toxicological role of NDMA, the environmental factors that condition the exposure to this compound, especially its precursors- nitrates arouse wide concern. Results: In this article, we present a detailed summary of the molecular mechanisms of NDMA’s effect on the iNOS-dependent NO production in human neutrophils. Conclusion: This research contributes to a more complete understanding of the mechanisms that explain the changes that occur during nonspecific cellular responses to NDMA toxicity.

scholarly journals De novo synthesis of diacylglycerol from glucose. A new pathway of signal transduction in human neutrophils stimulated during phagocytosis of beta-glucan particles

1991 ◽  
Vol 266 (13) ◽  
pp. 8034-8038
Author(s):  
F. Rossi ◽  
M. Grzeskowiak ◽  
V. Della Bianca ◽  
A. Sbarbati
Keyword(s):  
Signal Transduction ◽  
De Novo ◽  
Human Neutrophils ◽  
De Novo Synthesis ◽  
Beta Glucan

scholarly journals Plasma membrane potential modulates chemotactic peptide-stimulated cytosolic free Ca2+ changes in human neutrophils.

1987 ◽  
Vol 262 (10) ◽  
pp. 4574-4579 ◽  
Author(s):  
F. Di Virgilio ◽  
P.D. Lew ◽  
T. Andersson ◽  
T. Pozzan
Keyword(s):  
Plasma Membrane ◽  
Membrane Potential ◽  
Human Neutrophils ◽  
Chemotactic Peptide ◽  
Plasma Membrane Potential

scholarly journals A monoclonal antibody to a human neutrophil-specific plasma membrane antigen. Effect of the antibody on the C3bi-mediated adherence by neutrophils and expression of the antigen during myelopoiesis.

1988 ◽  
Vol 167 (2) ◽  
pp. 421-439 ◽  
Author(s):  
B Pytowski ◽  
T G Easton ◽  
J E Valinsky ◽  
T Calderon ◽  
T Sun ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Bone Marrow Cells ◽  
Human Lymphocytes ◽  
Leukemic Cell ◽  
Human Neutrophils ◽  
Binding Studies ◽  
Granulocytic Differentiation ◽  
Average Molecular Mass ◽  
Cytochemical Analysis ◽  
Normal Human

We have used mice selectively tolerized to antigens of human lymphocytes by treatment with cyclophosphamide to raise an mAb, BH2-C6, that reacts with a plasma membrane antigen specific for human neutrophils. This specificity is demonstrated by indirect immunofluorescence microscopy, cytochemical analysis of fluorescence-positive and -negative cell populations separated by flow cytometry, and by the selective, complement-mediated killing of mAb BH2-C6-treated neutrophils. Additional evidence for the neutrophil specificity of mAb BH2-C6 is shown by immunoelectron microscopy, which demonstrates a lack of reactivity with human eosinophils. Immunoblotting of SDS-PAGE-separated proteins of polymorphonuclear leukocytes with 125I-labeled BH2-C6 identifies protein with an average molecular mass of 157 kD. Binding studies show that, at saturation, neutrophils bind 214,000 molecules of 125I-BH2-C6 per cell. Addition of mAb BH2-C6 to neutrophils significantly reduces the number of C3bi-opsonized sheep erythrocytes (EIgMC3bi) bound by these cells. This reduction is partly reversed by the presence of soybean trypsin inhibitor (SBTI), indicating that at least one part of this inhibition is due to BH2-C6-stimulated secretion of a serine protease that may affect ligand binding. Cytochemical analysis of normal human bone marrow cells sorted by cytofluorimetry identifies the promyelocyte as the precursor cell that first expresses BH2-Ag on the plasma membrane. Using the leukemic cell line HL-60, we demonstrate that only inducers of granulocytic differentiation, cis-retinoic acid, and dimethyloxazolidine stimulate the expression of BH2-Ag. These results show that the expression of BH2-Ag during myelomonocytic differentiation is a property uniquely possessed by cells committed to the neutrophilic lineage.

scholarly journals Activation of Rac2 and Cdc42 on Fc and complement receptor ligation in human neutrophils

2003 ◽  
Vol 74 (4) ◽  
pp. 611-619 ◽  
Author(s):  
Maria Forsberg ◽  
Pia Druid ◽  
Limin Zheng ◽  
Olle Stendahl ◽  
Eva Särndahl
Keyword(s):  
Human Neutrophils ◽  
Complement Receptor ◽  
Receptor Ligation

scholarly journals Counterregulation of clathrin-mediated endocytosis by the actin and microtubular cytoskeleton in human neutrophils

2009 ◽  
Vol 296 (4) ◽  
pp. C857-C867 ◽  
Author(s):  
Silvia M. Uriarte ◽  
Neelakshi R. Jog ◽  
Gregory C. Luerman ◽  
Samrath Bhimani ◽  
Richard A. Ward ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Actin Cytoskeleton ◽  
Human Neutrophils ◽  
Functional Responses ◽  
Membrane Expression ◽  
Granule Exocytosis ◽  
Plasma Membrane Expression ◽  
Microtubular Cytoskeleton ◽  
Latrunculin A ◽  
Azurophil Granule

We have recently reported that disruption of the actin cytoskeleton enhanced N-formylmethionyl-leucyl-phenylalanine (fMLP)-stimulated granule exocytosis in human neutrophils but decreased plasma membrane expression of complement receptor 1 (CR1), a marker of secretory vesicles. The present study was initiated to determine if reduced CR1 expression was due to fMLP-stimulated endocytosis, to determine the mechanism of this endocytosis, and to examine its impact on neutrophil functional responses. Stimulation of neutrophils with fMLP or ionomycin in the presence of latrunculin A resulted in the uptake of Alexa fluor 488-labeled albumin and transferrin and reduced plasma membrane expression of CR1. These effects were prevented by preincubation of the cells with sucrose, chlorpromazine, or monodansylcadaverine (MDC), inhibitors of clathrin-mediated endocytosis. Sucrose, chlorpromazine, and MDC also significantly inhibited fMLP- and ionomycin-stimulated specific and azurophil granule exocytosis. Disruption of microtubules with nocodazole inhibited endocytosis and azurophil granule exocytosis stimulated by fMLP in the presence of latrunculin A. Pharmacological inhibition of phosphatidylinositol 3-kinase, ERK1/2, and PKC significantly reduced fMLP-stimulated transferrin uptake in the presence of latrunculin A. Blockade of clathrin-mediated endocytosis had no significant effect on fMLP-stimulated phosphorylation of ERK1/2 in neutrophils pretreated with latrunculin A. From these data, we conclude that the actin cytoskeleton functions to limit microtubule-dependent, clathrin-mediated endocytosis in stimulated human neutrophils. The limitation of clathrin-mediated endocytosis by actin regulates the extent of both specific and azurophilic granule exocytosis.

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