scholarly journals A novel neutrophil-activating factor produced by human mononuclear phagocytes.

1988 ◽  
Vol 167 (5) ◽  
pp. 1547-1559 ◽  
Author(s):  
P Peveri ◽  
A Walz ◽  
B Dewald ◽  
M Baggiolini
Keyword(s):  
Respiratory Burst ◽  
Time Course ◽  
De Novo ◽  
Platelet Activating Factor ◽  
Biological Properties ◽  
Leukotriene B4 ◽  
Mononuclear Phagocytes ◽  
Human Neutrophils ◽  
Blood Monocytes ◽  
Surface Receptor

The biological properties of a neutrophil-activating factor (NAF), which was recently identified as a novel peptide of approximately 6,000 mol wt, are described. NAF is produced de novo by human blood monocytes upon stimulation with LPS, PHA, and Con A. It induces two main responses in human neutrophils, i.e., exocytosis (release from specific granules in normal, and from specific and azurophil granules in cytochalasin B-treated cells) and the respiratory burst (formation of superoxide and hydrogen peroxide). The action of NAF appears to be mediated by a surface receptor as shown by the following observations. (a) NAF induces a rapid and transient rise in cytosolic free Ca2+; (b) interaction with NAF results in desensitization, since the cells do not respond to a second NAF challenge; and (c) the respiratory burst elicited by NAF is similar in onset, and time course to that induced by C5a or FMLP. The NAF receptor can be distinguished from the receptors of C5a, FMLP, platelet-activating factor, and leukotriene B4 by the lack of cross-desensitization. Unlike C5a, the other host-derived neutrophil-activating peptide, NAF is not inactivated by serum and thus presumably accumulates in inflamed tissue.

Phospholipase A2 activation in human neutrophils requires influx of extracellular Ca2+ and leukotriene B4

1995 ◽  
Vol 268 (1) ◽  
pp. C138-C146 ◽  
Author(s):  
S. Reddy ◽  
R. Bose ◽  
G. H. Rao ◽  
M. Murthy
Keyword(s):  
Ethylene Glycol ◽  
Phospholipase A2 ◽  
Platelet Activating Factor ◽  
Leukotriene B4 ◽  
Lipid Mediators ◽  
Oxidation Products ◽  
Human Neutrophils ◽  
Tetraacetic Acid ◽  
A 23187 ◽  
Transient Elevation

We have demonstrated that phospolipase A2 (PLA2) activation in human neutrophils requires both the influx of extracellular Ca2+ and leukotriene B4 (LTB4). Surprisingly, the eicosanoids (LTB4 and its omega-oxidation products) formed were quantitatively very similar in both thapsigargin (Thap)- and A-23187-stimulated neutrophils. In contrast, Thap had very little effect on the activation of PLA2 when 5-lipoxygenase (5-LO) was blocked by BW755C or MK-886, whereas A-23187 caused a substantial activation. The lack of PLA2 activation in Thap-stimulated neutrophils results from the inhibition of LTB4 formation in the presence of 5-LO inhibitors. It appears that A-23187 activates both LTB4-dependent and -independent PLA2, whereas Thap activates LTB4-dependent PLA2. Experiments with ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid demonstrated that activation of Thap-sensitive PLA2 and 5-LO requires the influx of Ca2+. Neither the transient elevation of cytosolic Ca2+ from intracellular stores nor the sustained Ca2+ influx alone without LTB4 appears sufficient to cause the activation of LTB4-dependent PLA2. We suggest that the activation of LTB4-dependent PLA2 involves 1) a sustained elevation of cytosolic Ca2+ coupled to the influx of extracellular Ca2+ and 2) a coupling between LTB4 and its receptor. We conclude that LTB4-dependent PLA2 plays an important role in the poststimulatory formation of lipid mediators such as prostaglandins, leukotrienes, and platelet-activating factor.

scholarly journals Human neutrophils express the alpha 1-antitrypsin gene and produce alpha 1-antitrypsin

Blood ◽  
1991 ◽  
Vol 77 (12) ◽  
pp. 2724-2730
Author(s):  
RM du Bois ◽  
JF Bernaudin ◽  
P Paakko ◽  
R Hubbard ◽  
H Takahashi ◽  
...  
Keyword(s):  
Messenger Rna ◽  
De Novo ◽  
Sodium Dodecyl ◽  
Mononuclear Phagocytes ◽  
Northern Analysis ◽  
Human Neutrophils ◽  
Normal Tissues ◽  
Rna Transcripts ◽  
Neutrophil Degranulation ◽  
Alpha 1 Antitrypsin

The potent serine protease, neutrophil elastase (NE), is stored in neutrophil azurophilic granules, where it is available to degrade phagocytosed material and can be released by the cell to assist in tissue migration and help clear tissue debris. While neutrophils carry NE, they cannot produce it; the NE gene is expressed only in bone marrow granulocyte precursor cells. Protection of normal tissues from the destructive capacity of NE is provided by alpha 1-antitrypsin (alpha 1 AT), a 52-Kd serine antiprotease produced by hepatocytes and mononuclear phagocytes. In the context of the broad destructive capacity of NE, we evaluated the concept that human neutrophils may be able to modulate the extracellular activity of NE by synthesizing and secreting alpha 1AT. Immunocytochemical analysis demonstrated that the neutrophil contains alpha 1AT. Northern analysis and in situ hybridization with alpha 1AT-specific probes demonstrated the presence of alpha 1AT messenger RNA transcripts within neutrophils. [35S]methionine-labeling of neutrophils followed by immunoprecipitation of the supernatant with an anti-alpha 1AT antibody and sodium dodecyl sulfate-acrylamide gel analysis demonstrated that neutrophils can synthesize alpha 1AT de novo and secrete the synthesized molecule. In the presence of major neutrophil degranulation, the antiprotease effect of neutrophil alpha 1AT is overwhelmed, allowing the NE to act unopposed in the extracellular microenvironment. However, in conditions where small amounts of NE are released by neutrophils, at least some of the secreted newly synthesized alpha 1AT was capable of complexing with NE. Thus, despite the fact that the neutrophil cannot synthesize NE, it can synthesize and secrete alpha 1AT, the inhibitor of NE, ie, the neutrophil is capable, to some extent, of modulating NE activity in the local milieu without the help of antiproteases produced by other cells.

scholarly journals Identification and characterization of specific receptors for monocyte-derived neutrophil chemotactic factor (MDNCF) on human neutrophils.

1989 ◽  
Vol 169 (3) ◽  
pp. 1185-1189 ◽  
Author(s):  
A K Samanta ◽  
J J Oppenheim ◽  
K Matsushima
Keyword(s):  
Human Peripheral Blood ◽  
Platelet Activating Factor ◽  
Leukotriene B4 ◽  
Chemotactic Factor ◽  
Single Type ◽  
Human Neutrophils ◽  
Scatchard Analysis ◽  
Specific Receptors ◽  
Neutrophil Chemotactic Factor

Specific receptors for a recently purified and cloned monocyte-derived neutrophil chemotactic factor (MDNCF) have been identified on the surface of normal human peripheral blood neutrophils using 125I-labeled recombinant human MDNCF (125I-MDNCF). Competitive binding of 125I-MDNCF to human neutrophils reached a maximal level at 1-3 h at 4 degrees C. The Scatchard analysis showed that there are approximately 20,000 receptors per cell with a single type of high affinity binding (Kd, 8 x 10(-10) M). The receptors for MDNCF are clearly distinct from the receptors for other cytokines and chemotactic agents, e.g., IL-1 alpha, TNF-alpha, and FMLP, C5a, leukotriene B4, and platelet activating factor. Based on the SDS-PAGE analysis of chemically crosslinked 125I-MDNCF receptor complex, there are two polypeptides that bind MDNCF; the molecular weight of these two MDNCF receptors were estimated to be 67,000 and 59,000. Treatment of a promyelocytic cell line, HL60, with 1.25% DMSO for 5 d in vitro increased the number of receptors up to 7,000 receptors/cell with a Kd of 1.2 x 10(-9) M.

scholarly journals Involvement of guanine nucleotide binding proteins in neutrophil activation and priming by GM-CSF

Blood ◽  
1989 ◽  
Vol 73 (2) ◽  
pp. 588-591 ◽  
Author(s):  
SR McColl ◽  
C Kreis ◽  
JF DiPersio ◽  
P Borgeat ◽  
PH Naccache
Keyword(s):  
Pertussis Toxin ◽  
Platelet Activating Factor ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
Human Neutrophils ◽  
Ionophore A23187 ◽  
Gm Csf ◽  
Surface Receptor ◽  
Pre Treatment ◽  
Guanine Nucleotide Binding

Abstract Pre-incubation of human neutrophils with pertussis toxin significantly inhibited the neutrophil-directed biologic actions of granulocyte- macrophage colony-stimulating factor (GM-CSF) in three separate assays: the induction of c-fos mRNA, the enhancement of both platelet- activating factor-induced mobilization of intracellular calcium, and stimulation of leukotriene synthesis by the calcium ionophore A23187. Cholera toxin did not have an effect on the latter two assays. Pre- treatment of human neutrophils with pertussis toxin did not affect the binding of GM-CSF to its surface receptor. These results provide the first evidence that a pertussis toxin substrate plays an important mediatory role in the mechanism of action of GM-CSF.

scholarly journals Early signalling events implicated in leukotriene B4-induced activation of the NADPH oxidase in eosinophils: role of Ca2+, protein kinase C and phospholipases C and D

1995 ◽  
Vol 310 (3) ◽  
pp. 795-806 ◽  
Author(s):  
R S Perkins ◽  
M A Lindsay ◽  
P J Barnes ◽  
M A Giembycz
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Nadph Oxidase ◽  
Respiratory Burst ◽  
Leukotriene B4 ◽  
Human Neutrophils ◽  
H2o2 Production ◽  
Intact Cells ◽  
Kinase C ◽  
H2o2 Generation

The early signalling events that may ultimately contribute to the assembly and subsequent activation of the NADPH oxidase in guinea-pig peritoneal eosinophils were investigated in response to leukotriene B4 (LTB4). LTB4 promoted a rapid, transient and receptor-mediated increase in the rate of H2O2 generation that was potentiated by R 59 022, a diradylglycerol (DRG) kinase inhibitor, implicating protein kinase C (PKC) in the genesis of this response. This conclusion was supported by the finding that the PKC inhibitor, Ro 31-8220, attenuated (by about 30%) the peak rate of LTB4-induced H2O2 generation under conditions where the same response evoked by 4 beta-phorbol 12,13-dibutyrate (PDBu) was inhibited by more than 90%. Paradoxically, Ro 31-8220 doubled the amount of H2O2 produced by LTB4 which may relate to the ability of PKC to inhibit cell signalling through phospholipase C (PLC). Indeed, Ro 31-8220 significantly enhanced LTB4-induced Ins(1,4,5)P3 accumulation and the duration of the Ca2+ transient in eosinophils. Experiments designed to assess the relative importance of DRG-mobilizing phospholipases in LTB4-induced oxidase activation indicated that phospholipase D (PLD) did not play a major role. Thus, although H2O2 generation was abolished by butan-1-ol, this was apparently unrelated to the inhibition of PLD, as LTB4 failed to stimulate the formation of Ptd[3H]BuOH in [3H]butan-1-ol-treated eosinophils. Rather, the inhibition was probably due to the ability of butan-1-ol to increase the eosinophil cyclic AMP content. In contrast, Ca(2+)- and PLC-driven mechanisms were implicated in H2O2 generation, as LTB4 elevated the Ins(1,4,5)P3 content and intracellular free Ca2+ concentration in intact cells, and cochelation of extracellular and intracellular Ca2+ significantly attenuated LTB4-induced H2O2 generation. Pretreatment of eosinophils with wortmannin did not affect LTB4-induced H2O2 production at concentrations at which it abolished the respiratory burst evoked by formylmethionyl-leucylphenylalanine in human neutrophils. Collectively, these data suggest that LTB4 activates the NADPH oxidase in eosinophils by PLD- and PtdIns 3-kinase-independent mechanisms that involve Ca2+, PLC and PKC. Furthermore, the activation of additional pathways that do not require Ca2+ is also suggested by the finding that LTB4 evoked a significant respiratory burst in Ca(2+)-depleted cells.

scholarly journals Phagocytosis of senescent neutrophils by human monocyte-derived macrophages and rabbit inflammatory macrophages.

1982 ◽  
Vol 156 (2) ◽  
pp. 430-442 ◽  
Author(s):  
S L Newman ◽  
J E Henson ◽  
P M Henson
Keyword(s):  
Human Monocyte ◽  
Mononuclear Phagocytes ◽  
Polymorphonuclear Neutrophils ◽  
Human Neutrophils ◽  
Dependent Manner ◽  
Blood Monocytes ◽  
Peripheral Blood Monocytes ◽  
In Vitro System ◽  
Inflammatory Macrophages

An in vitro system to investigate the ability of macrophages to recognize and ingest senescent polymorphonuclear neutrophils has been used that uses chromium-labeled neutrophils and staining for myeloperoxidase (MPO). Human monocyte-derived macrophages obtained from in vitro cultures were able to recognize "aged" but not freshly isolated 51Cr-labeled human neutrophils and ingest them. Freshly isolated monocytes did not exhibit this property. Because the aged neutrophils were greater than 95% viable, death did not appear to be a prerequisite for recognition and ingestion. Serum was not required for the aging of the neutrophils, and when serum was used, different concentrations did not appear to effect the aging process; that is, neutrophils aged in different concentrations of serum were ingested equally. Phagocytosis of senescent neutrophils by macrophages occurred in a time-dependent manner and was also dependent on the number of neutrophils added. Monocyte-derived macrophages first exhibited the ability to phagocytose senescent neutrophils on the 3rd d of culture, with the percentage of active macrophages increasing through day 7. In experiments with rabbit mononuclear phagocytes, immune complex-induced inflammatory macrophages from the lung but not resident bronchoalveolar macrophages or peripheral blood monocytes were found to be capable of recognition and ingestion of senescent rabbit neutrophils. These data suggest that the monocyte maturation process, akin to that seen during inflammation, is necessary in vitro before macrophages recognize and remove senescent neutrophils.

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