scholarly journals Enhancement of chemotactic factor-stimulated neutrophil oxidative metabolism by leukotriene B4

Blood ◽  
1984 ◽  
Vol 64 (4) ◽  
pp. 780-785
Author(s):  
JC Gay ◽  
JK Beckman ◽  
AR Brash ◽  
JA Oates ◽  
JN Lukens
Keyword(s):  
Neutrophil Function ◽  
Leukotriene B4 ◽  
Human Neutrophils ◽  
Neutrophil Chemotaxis ◽  
Myristate Acetate ◽  
Fmlp Receptor ◽  
Dose Dependent ◽  
O2 Production ◽  
Oxygen Metabolites ◽  
Oxidative Responses

Leukotriene B4 (LTB4) is a potent primary stimulator of neutrophil chemotaxis, aggregation, and degranulation and induces superoxide production at higher concentrations. In order to determine whether LTB4 modulates neutrophil responses to oxidative stimuli, human neutrophils (PMNs) were incubated with LTB4 prior to stimulation with f-Met-Leu-Phe (fMLP, 10(-7) mol/L), opsonized zymosan (OZ, 250 micrograms/mL), or phorbol myristate acetate (PMA, 32 nmol/L). Superoxide (O2-) production by stimulated PMNs was assessed by the superoxide dismutase-inhibitable reduction of cytochrome c. LTB4 alone did not stimulate O2- production in concentrations below 10(-7) mol/L and had no effect on the O2- assay. In the concentration range of 10(-12) to 10(-8) mol/L, LTB4 did not alter O2- release induced by OZ or PMA. In contrast, LTB4-treated cells demonstrated enhanced O2- production following exposure to fMLP, and in the presence of 10 nmol/LLTB4, generated 180% +/- 41% of O-2 quantities produced by control cells (n = 23). Enhancement was LTB4 dose-dependent, was maximal in the range of 1 to 10 nmol/L LTB4, was not reversed by removal of the lipid from the medium prior to fMLP stimulation, and was not dependent on the presence of Ca++ or Mg++ in the suspending medium. Chemiluminescence of fMLP-stimulated neutrophils was increased to 323% of controls in neutrophils preincubated with 10 nmol/L LTB4. Unlike augmentation of oxidative responses to fMLP seen with other degranulating stimuli, enhancement by LTB4 was not correlated with an increase in 3H-fMLP receptor binding. These results indicate that, in addition to its primary effects on neutrophil function, LTB4 modulates PMN oxidative responses to the chemotactic peptide and, thus, may amplify the release of oxygen metabolites at inflammatory foci.

scholarly journals Enhancement of chemotactic factor-stimulated neutrophil oxidative metabolism by leukotriene B4

Blood ◽  
1984 ◽  
Vol 64 (4) ◽  
pp. 780-785 ◽  
Author(s):  
JC Gay ◽  
JK Beckman ◽  
AR Brash ◽  
JA Oates ◽  
JN Lukens
Keyword(s):  
Neutrophil Function ◽  
Leukotriene B4 ◽  
Human Neutrophils ◽  
Neutrophil Chemotaxis ◽  
Myristate Acetate ◽  
Fmlp Receptor ◽  
Dose Dependent ◽  
O2 Production ◽  
Oxygen Metabolites ◽  
Oxidative Responses

Abstract Leukotriene B4 (LTB4) is a potent primary stimulator of neutrophil chemotaxis, aggregation, and degranulation and induces superoxide production at higher concentrations. In order to determine whether LTB4 modulates neutrophil responses to oxidative stimuli, human neutrophils (PMNs) were incubated with LTB4 prior to stimulation with f-Met-Leu-Phe (fMLP, 10(-7) mol/L), opsonized zymosan (OZ, 250 micrograms/mL), or phorbol myristate acetate (PMA, 32 nmol/L). Superoxide (O2-) production by stimulated PMNs was assessed by the superoxide dismutase-inhibitable reduction of cytochrome c. LTB4 alone did not stimulate O2- production in concentrations below 10(-7) mol/L and had no effect on the O2- assay. In the concentration range of 10(-12) to 10(-8) mol/L, LTB4 did not alter O2- release induced by OZ or PMA. In contrast, LTB4-treated cells demonstrated enhanced O2- production following exposure to fMLP, and in the presence of 10 nmol/LLTB4, generated 180% +/- 41% of O-2 quantities produced by control cells (n = 23). Enhancement was LTB4 dose-dependent, was maximal in the range of 1 to 10 nmol/L LTB4, was not reversed by removal of the lipid from the medium prior to fMLP stimulation, and was not dependent on the presence of Ca++ or Mg++ in the suspending medium. Chemiluminescence of fMLP-stimulated neutrophils was increased to 323% of controls in neutrophils preincubated with 10 nmol/L LTB4. Unlike augmentation of oxidative responses to fMLP seen with other degranulating stimuli, enhancement by LTB4 was not correlated with an increase in 3H-fMLP receptor binding. These results indicate that, in addition to its primary effects on neutrophil function, LTB4 modulates PMN oxidative responses to the chemotactic peptide and, thus, may amplify the release of oxygen metabolites at inflammatory foci.

scholarly journals Suppression of monocyte and neutrophil function by recombinant IL-2

1993 ◽  
Vol 2 (1) ◽  
pp. 59-65 ◽  
Author(s):  
Susan E. Smith ◽  
Gayle D. Warren ◽  
Yee-Hing Thong ◽  
Joe G. McCormack
Keyword(s):  
Glucose Uptake ◽  
Neutrophil Migration ◽  
Neutrophil Function ◽  
Biologically Active ◽  
Hexose Monophosphate ◽  
Myristate Acetate ◽  
Hexose Monophosphate Shunt ◽  
Neutrophil Adherence ◽  
Dose Dependent ◽  
Monocyte Adherence

Little IS known about the influence of IL-2 on phagocytes. We now describe the effects of human recombinant IL-2 on human neutrophil and monocyte functions related to mobility, phagocytosis, glucose uptake, respiration and degranulation. Neutrophil adherence and hexose monophosphate shunt activities were both suppressed after incubation with IL-2. IL-2 had no effect on neutrophil migration, phagocytosis, deoxyglucose uptake or degranulation, ionocytes demonstrated a greater sensitivity to IL-2 with suppression of monocyte adherence, random and stimulated migration, glucose uptake and hexose monophosphate shunt activity, even after addition of phorbol myristate acetate. Monocyte phagocytosis and degranulation were not affected. All of the effects observed were dose-dependent within a biologically active range for IL-2. These studies suggest that IL-2 may have an important down-regulatory role across a broad range of monocyte functions including movement, deoxyglucose uptake and respiration. However, its role in regulation of neutrophil function is limited to adherence and respiration. IL-2 may be a more versatile cytokine than has previously been appreciated.

L-selectin function is required for beta 2-integrin-mediated neutrophil adhesion at physiological shear rates in vivo

1992 ◽  
Vol 263 (4) ◽  
pp. H1034-H1044 ◽  
Author(s):  
U. H. Von Andrian ◽  
P. Hansell ◽  
J. D. Chambers ◽  
E. M. Berger ◽  
I. Torres Filho ◽  
...  
Keyword(s):  
Neutrophil Function ◽  
Leukotriene B4 ◽  
Human Neutrophils ◽  
Neutrophil Adhesion ◽  
Shear Rates ◽  
Sequence Of Events ◽  
Multistep Process ◽  
Beta 2

In vivo interactions between neutrophils and endothelial cells (EC) follow a multistep process involving two distinct neutrophil adhesion receptors. L-selectin, constitutively functional on resting neutrophils, mediates an activation-independent primary interaction resulting in rolling along the venular wall. Subsequent activation of rolling neutrophils induces upregulation and functional activation of beta 2-integrins (CD11/CD18) leading to firm attachment. Based on previous findings we hypothesized that, under shear force, rolling may be essential for successful neutrophil-EC recognition. Here we report results of our studies of human neutrophil behavior in interleukin (IL)-1-activated rabbit mesentery venules, an interaction that requires both L-selectin and beta 2-integrins. Rolling of human neutrophils is L-selection mediated; it was strongly reduced by monoclonal antibody inhibition or enzymatic removal of L-selectin. Furthermore, activation induced L-selectin shedding and, in a dose- and time-dependent fashion, rendered neutrophils unable to recognize inflamed EC despite expression of active beta 2-integrins, which promoted adhesion in vitro. Neutrophils activated for 5 min or longer lost most of their ability to roll. However, 1-3 min after activation, rolling was reduced (not abolished), and cells that were still able to roll displayed a significant tendency for a CD18-dependent transition from rolling to sticking. The whole sequence of events, rolling, sticking, and transendothelial migration, could be observed if an extravascular chemotactic stimulus was applied by superfusing mesenteries with leukotriene B4. Under such conditions, sticking and emigration was blocked when rolling was inhibited by enzymatic removal of L-selectin. Our results indicate that primary neutrophil interaction with inflamed EC through the L-selectin is a prerequisite for neutrophil function at physiological shear rates in vivo.

scholarly journals A newly synthesized molecule derived from ruthenium cation, with antitumour activity, activates NADPH oxidase in human neutrophils

1997 ◽  
Vol 328 (2) ◽  
pp. 559-564 ◽  
Author(s):  
Modesto CARBALLO ◽  
Rosario VILAPLANA ◽  
Gracia MÁRQUEZ ◽  
Manuel CONDE ◽  
J. Francisco BEDOYA ◽  
...  
Keyword(s):  
Nadph Oxidase ◽  
Antitumour Activity ◽  
Human Neutrophils ◽  
Phagocytic Cells ◽  
Diphenylene Iodonium ◽  
Ru Complexes ◽  
O2 Production ◽  
Cytosolic Factors ◽  
Oxygen Metabolites ◽  
Antitumour Effects

To determine the nature of the mechanism by which certain derived ruthenium (Ru) complexes induce regression in tumour growth, we have investigated the possibility that this mechanism was associated with an increase of superoxide anion (O2-•) production by phagocytic cells, which are usually found in tumour nodes. Here we present evidence that a newly synthesized complex, Ru3+-propylene-1,2-diaminotetra-acetic acid (Ru-PDTA), derived from Ru and the sequestering ligand (PDTA), specifically stimulates O2-• production. This increase was associated with the translocation of cytosolic factors p47phox and p67phox of NADPH oxidase to the plasma membrane. The Ru-PDTA-complex-dependent O2-• production was abrogated by staurosporine, partially inhibited by diphenylene iodonium, and it was insensitive to pertussis toxin or dibutyryl cyclic AMP pretreatment. An increase of cytosolic Ca2+ levels were also detected in neutrophils treated with the Ru-PDTA complex. Also, Ru-PDTA complex induced the phosphorylation of tyrosine residues of several proteins as assessed by Western blotting. Present data are consistent with the possibility that Ru-PDTA-dependent antitumour effects are due in part to the complex's ability to stimulate the release of toxic oxygen metabolites from phagocytic cells infiltrating tumour masses.

scholarly journals Graded responses of human neutrophils induced by serum-treated zymosan

Blood ◽  
1985 ◽  
Vol 66 (5) ◽  
pp. 1182-1188 ◽  
Author(s):  
JC Whitin ◽  
DH Ryan ◽  
HJ Cohen
Keyword(s):  
Flow Cytometry ◽  
Membrane Potential ◽  
Fluorescent Probe ◽  
Dose Response ◽  
Dose Dependence ◽  
Human Neutrophils ◽  
Graded Responses ◽  
Dose Dependent ◽  
O2 Production ◽  
Stimulation Of

Abstract A modified zymosan preparation was used to probe the interaction of particulate stimuli with human neutrophils (PMNs). After extraction with alkali and detergent, the zymosan particles retained their ability to be opsonized in serum and to stimulate PMNs. Serum-treated zymosan (STZ) induced dose-dependent superoxide (O2-) production and membrane potential depolarization in the range of 1 to 10 mg/mL of STZ. The rate and extent of secretion of lysozyme and beta-glucuronidase were also dose-dependent in the range of 1 to 10 mg/mL of STZ. Cytochemical studies using nitroblue tetrazolium, however, showed that 92% of PMNs were stimulated to produce O2- at 0.1 mg/mL of STZ. The dose response of O2- production induced by STZ is therefore due to increasing O2- production by individual PMNs and not to the stimulation of more PMNs to produce O2-. Evidence for O2- production was found only in the area of PMN-zymosan contact, suggesting a mechanism for the graded responses of PMNs treated with particulate stimuli. In order to determine the nature of the dose dependence of depolarization (a measure of PMN activation), PMNs equilibrated with the fluorescent probe 3,3′- dipentyloxacarbocyanine were analyzed by flow cytometry. The results demonstrate that STZ induces a dose-dependent depolarization of the membrane potential of individual PMNs. These results also demonstrate that increasing concentrations of STZ can induce increasing PMN responses even when all of the PMNs have been activated. These results are consistent with the hypothesis that receptor-mediated particulate stimulation of PMNs is a phenomenon that results in graded PMN responses.

scholarly journals Monocyte-associated tissue factor is suppressed by phorbol myristate acetate

Blood ◽  
1988 ◽  
Vol 72 (2) ◽  
pp. 456-462 ◽  
Author(s):  
JP Brozna ◽  
SD Carson
Keyword(s):  
Tissue Factor ◽  
Phorbol Myristate Acetate ◽  
Immunofluorescent Staining ◽  
Blood Monocytes ◽  
Factor Activity ◽  
Myristate Acetate ◽  
Tissue Factor Activity ◽  
Dose Dependent ◽  
Oxygen Metabolites ◽  
Factor Antigen

Abstract The monocyte is the only normal circulating cell type capable of initiating blood coagulation through the expression of tissue factor. Recently isolated peripheral blood monocytes that contain no demonstrable tissue factor activity can be induced to express tissue factor activity by a number of stimulatory agents. Monocyte-associated tissue factor activity transiently increases in response to adherence to tissue culture plates and, consistent with other reports, markedly increases after the isolated monocytes are treated with endotoxin. Phorbol myristate acetate (PMA) induced an increase in tissue factor activity at low doses (10(-11) to 10(-12) mol/L). Conversely, concentrations of PMA that stimulate release of oxygen metabolites or that cause the cytosol-to-membrane translocation of protein kinase C (PKC) (10(-9) to 10(-7) mol/L) resulted in a rapid decrease in both adherence-induced and endotoxin-induced monocyte tissue factor activity. The effects of PMA on monocytes were time- and dose-dependent with respect to PKC translocation, release of oxygen metabolites, and changes in tissue factor activity. Immunofluorescent staining of monocytes with monoclonal antibody (MoAb) HTF1–7B8, directed against human tissue factor, revealed that tissue factor antigen was induced concurrently with tissue factor activity by adherence and endotoxin and that tissue factor antigen decreased after PMA stimulation.

scholarly journals Modulation of neutrophil oxidative responses to soluble stimuli by platelet-activating factor

Blood ◽  
1986 ◽  
Vol 67 (4) ◽  
pp. 931-936 ◽  
Author(s):  
JC Gay ◽  
JK Beckman ◽  
KA Zaboy ◽  
JN Lukens
Keyword(s):  
Feedback Loop ◽  
Divalent Cations ◽  
Platelet Activating Factor ◽  
Tumor Promoter ◽  
Chemotactic Peptide ◽  
Myristate Acetate ◽  
Neutrophil Superoxide ◽  
O2 Production ◽  
Oxidative Responses

Abstract The role of platelet activating factor (PAF) as a regulator of human neutrophil superoxide (O2-) generation in response to soluble and particulate stimuli was examined. At concentrations greater than 10(-7) mol/L, PAF alone induced a brief burst of O2- production. When cells were exposed to PAF and either the chemotactic peptide n-formyl- methionyl-leucyl-phenylalanine (FMLP 10(-7) mol/L) or the tumor promoter phorbol myristate acetate (PMA 10 ng/mL), a marked synergistic augmentation of O2- release was noted when compared to control cells stimulated with FMLP or PMA alone. Mean percentage of enhancement by 10(-5) mol/L of PAF was 297% +/- 35% (n = 9) of control responses to FMLP and 185% +/- 16% (n = 3) of control responses to PMA. Consistent enhancement occurred with PAF concentrations of as low as 10(-9) mol/L. Enhancement could be demonstrated when neutrophils were exposed to PAF either at the same time as, or up to 60 minutes prior to, the second stimulus, and was neither reversed by removal of PAF from the medium prior to addition of FMLP or PMA nor dependent on the presence of extracellular divalent cations. Continuous recordings revealed that the enhancement was due to an increased maximal rate of O2- production. In contrast, PAF concentrations up to 10(-5) mol/L had only a minimal effect on the response to neutrophils to opsonized zymosan. Analysis of the enhancing properties of lipids structurally related to PAF revealed that the critical moiety was the saturated fatty acid at position 1. These results indicate the presence of a PAF-mediated positive feedback loop whereby the oxidative burst induced by some soluble stimuli is augmented. Modulation of neutrophil O2- production by PAF may serve to amplify neutrophil oxidative responses at sites of inflammation.

scholarly journals The role of phosphodiesterase 4B in IL-8/LTB4-induced human neutrophil chemotaxis evaluated with a phosphodiesterase 4B inhibitor

2015 ◽  
Vol 65 (2) ◽  
pp. 191-197 ◽  
Author(s):  
Osamu Suzuki ◽  
Taiji Goto ◽  
Toshiharu Yoshino ◽  
Satoshi Nakamura ◽  
Hiroaki Maeda
Keyword(s):  
Mononuclear Cells ◽  
Human Peripheral Blood ◽  
Physiological Role ◽  
Inhibitory Effect ◽  
Neutrophil Function ◽  
Chemotactic Response ◽  
Human Neutrophils ◽  
Neutrophil Chemotaxis ◽  
Compound A ◽  
Phosphodiesterase 4B

Abstract PDE4B was previously shown to be a dominant PDE4 subtype of neutrophils. However, its physiological role in the neutrophil function has not been evaluated. In this study, the inhibitory effects of a phosphodiesterase 4B (PDE4B)- selective inhibitor (compound A) and subtype non-selective PDE4 inhibitors (roflumilast and cilomilast) were evaluated in human peripheral blood cells. Compound A, roflumilast and cilomilast in a similar manner inhibited TNF-α production by LPS-stimulated human mononuclear cells. However, the inhibitory effect of compound A on IL-8 or LTB4-induced chemotactic response of neutrophils was modest even at the highest concentration (10 μmol L-1), whereas roflumilast and cilomilast inhibited IL-8 or LTB4-induced neutrophil chemotaxis. Our results suggest that PDE4B does not play an important role during the chemotactic response of human neutrophils.

scholarly journals Priming of neutrophils for enhanced release of oxygen metabolites by bacterial lipopolysaccharide. Evidence for increased activity of the superoxide-producing enzyme.

1984 ◽  
Vol 160 (6) ◽  
pp. 1656-1671 ◽  
Author(s):  
L A Guthrie ◽  
L C McPhail ◽  
P M Henson ◽  
R B Johnston
Keyword(s):  
Binding Sites ◽  
Calcium Ion ◽  
Metabolic Response ◽  
Human Neutrophils ◽  
Myristate Acetate ◽  
Wide Range ◽  
End Stage ◽  
Increased Activity ◽  
Oxygen Metabolites ◽  
Stimulation Of

We investigated the capacity of bacterial endotoxin (lipopolysaccharide, LPS) to modify the oxidative metabolic response to membrane stimulation of human neutrophils. Neutrophils were pretreated for 60 min with LPS, 10 ng/ml, then stimulated by exposure to fixed immune complexes, the chemotactic peptide formyl-methionyl-leucyl-phenylalanine (FMLP), or phorbol myristate acetate. Release of superoxide anion (O-2) was up to 7-times greater in cells preincubated with LPS, depending upon the stimulus used. Consumption of oxygen and release of hydrogen peroxide (H2O2) were similarly increased, using FMLP as stimulus. The enhancement was accompanied by a reduction in lag time and an increase in the rate of the response, but the duration of the oxidative events was not changed. The molecular basis for the augmented oxidative response of LPS-pretreated cells was investigated. Preincubation with LPS at 0 degrees C prevented priming, but preincubation in the presence of cycloheximide or chelation of extracellular calcium ion did not. Neutrophils preincubated with LPS had slightly decreased numbers of binding sites and equivalent binding affinity for radiolabeled FMLP. Possible changes in the enzyme responsible for the oxidative burst were analyzed by studying NADPH-dependent generation of O-2 by particulate fractions from cells preincubated with LPS or buffer, then stimulated before cell disruption. The fraction prepared from LPS-pretreated neutrophils exhibited greater release of O-2 over a wide range of concentrations of NADPH. The calculated apparent Km for NADPH was equivalent in the two fractions, but the Vmax was increased 2.5-fold in the subcellular fraction from LPS-pretreated cells. These results suggest that LPS could increase neutrophil-mediated host defense or the tissue damage associated with endotoxemia by enhancing the generation of oxygen metabolites by neutrophils. These results also support the concept that the neutrophil is not an end-stage cell in regard to function or metabolic activity.

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