scholarly journals Regulation of CD18 expression in human neutrophils as related to shape changes

1993 ◽  
Vol 106 (2) ◽  
pp. 493-501
Author(s):  
A. Volz
Keyword(s):  
Phorbol Myristate Acetate ◽  
Surface Expression ◽  
Cytochalasin D ◽  
Human Neutrophils ◽  
Chemotactic Peptide ◽  
Myristate Acetate ◽  
Surface Distribution ◽  
Quantitative Expression ◽  
High Concentrations ◽  
Shape Changes

The study analyses the distribution and quantitative expression of surface CD18 of neutrophils exposed to distinct stimuli that produce different types of continuous shape changes, including types that are associated with locomotion and others that are not. The chemotactic peptide N-formyl-L-norleucyl-L-leucyl-L-phenylalanine, colchicine and nocodazole were used to induce a polarized locomotor morphology, phorbol myristate acetate, 1,2-dioctanoylglycerol and 1-oleoyl-2-acetyl-glycerol to induce non-polar motile cells ruffling all over the surface and 2H2O to induce non-polar cells performing circus movements as have been previously described. Except for colchicine and nocodazole, these stimuli increased surface expression of CD18. Thus, stimulated shape changes are frequently, though not always, associated with increased surface expression of CD18. High concentrations (10(−7) to 10(−5) M) of phorbol myristate acetate but not of chemotactic peptide induced down-regulation of surface CD18. Cytochalasin D (10(−4) M) stimulated CD18 expression even though it inhibited shape changes. The surface distribution of CD18 determined by light microscopy was uniform in unstimulated cells or in various forms of stimulation except for cells treated with 10(−5) M cytochalasin D. Cytochalasin D (10(−5) M) produced CD18 accumulation at the pole opposite the F-actin cap. Experiments with colchicine, nocodazole, 2H2O and cytochalasin D suggest that microtubules as well as microfilaments modulate surface expression of CD18. The results suggest that protein kinase C and phosphatases play a role in regulating surface expression of CD18 in neutrophils.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Chemotactic factor enhancement of superoxide release from fluoride and phorbol myristate acetate stimulated neutrophils

Blood ◽  
1981 ◽  
Vol 58 (1) ◽  
pp. 129-134 ◽  
Author(s):  
D English ◽  
JS Roloff ◽  
JN Lukens
Keyword(s):  
Phorbol Myristate Acetate ◽  
Normal Serum ◽  
Human Neutrophils ◽  
Chemotactic Peptide ◽  
Myristate Acetate ◽  
Chemotactic Peptides ◽  
Extracellular Glucose ◽  
Increased Activity ◽  
Generating System ◽  
Superoxide Release

Abstract Human neutrophils exposed to chemotactic concentrations of zymosan- activated serum (ZAS) and a formylated chemotactic peptide (FMLP, 10(- 7)--10(-9) M) were markedly enhanced in their ability to generate superoxide (O2-) upon stimulation with either sodium fluoride or phorbol myristate acetate (PMA). For both fluoride and PMA, enhancement was characterized by a decrease in the lag from stimulation to initiation of superoxide release and by an increase in the rate of superoxide generation--representing faster activation and increased activity of O2- generating enzyme, respectively. Chemotactic concentrations of casein, normal serum, and casein-treated serum enhanced the activity, but not the rate of activation, of the fluoride- stimulated superoxide generating system. This effect on activity was not so impressive as that obtained with FMLP or ZAS. The mechanisms by which FMLP enhanced responsiveness to fluoride and PMA were found to be different. Optimal enhancement for fluoride-stimulated responses required extracellular Ca++. Extracellular glucose, but not extracellular Ca++, was required for enhancement of FMLP of PMA- stimulated responses. A similar glucose requirement could not be demonstrated for chemotactic peptide enhancement of the superoxide- generating system stimulated by fluoride. Fluoride and PMA apparently activate the neutrophil O2- generating enzyme by pathways that are not identical. However, responsiveness of the enzyme to both agents is susceptible to modulation by cellular responses to chemotactic peptides.

Effect of phorbol myristate acetate and the chemotactic peptide fNLPNTL on shape and movement of human neutrophils

1987 ◽  
Vol 88 (3) ◽  
pp. 399-406 ◽  
Author(s):  
F.J. Roos ◽  
A. Zimmermann ◽  
H.U. Keller
Keyword(s):  
Phorbol Myristate Acetate ◽  
Human Neutrophils ◽  
Chemotactic Peptide ◽  
Myristate Acetate ◽  
Locomotor Apparatus ◽  
Kinase C ◽  
Motile Cells ◽  
Chemotactic Peptides ◽  
Intracellular Organelles ◽  
Stimulation Of

The results show that the distinct types of shape produced by phorbol myristate acetate (PMA) and by chemotactic peptides (fNLPNTL) are associated with distinct types of neutrophil movement. Whereas the chemotactic peptide can induce front-tail polarity characterized by an expanding front, a contracted tail and preferential unidirectional movements of intracellular organelles, PMA can only elicit non-polar movements characterized by random formation and retraction of projections all over the surface, intracellular movements of organelles being ill-defined and changing in direction. Combined stimulation of human neutrophils with PMA and fNLPNTL results in a suppression of peptide-induced polarity and the formation of non-polar motile cells resembling those stimulated with PMA alone. The results suggest that the diacylglycerol-protein kinase C pathway may be instrumental in transducing or modulating signals to the locomotor apparatus of the cell. PMA-treated cells are, however, still capable of developing directional responses when appropriately stimulated. The findings lead to the hypothesis that distinct types of neutrophil movements are preferentially associated with distinct functions.

scholarly journals Chemotactic factor enhancement of superoxide release from fluoride and phorbol myristate acetate stimulated neutrophils

Blood ◽  
1981 ◽  
Vol 58 (1) ◽  
pp. 129-134 ◽  
Author(s):  
D English ◽  
JS Roloff ◽  
JN Lukens
Keyword(s):  
Phorbol Myristate Acetate ◽  
Normal Serum ◽  
Human Neutrophils ◽  
Chemotactic Peptide ◽  
Myristate Acetate ◽  
Chemotactic Peptides ◽  
Extracellular Glucose ◽  
Increased Activity ◽  
Generating System ◽  
Superoxide Release

Human neutrophils exposed to chemotactic concentrations of zymosan- activated serum (ZAS) and a formylated chemotactic peptide (FMLP, 10(- 7)--10(-9) M) were markedly enhanced in their ability to generate superoxide (O2-) upon stimulation with either sodium fluoride or phorbol myristate acetate (PMA). For both fluoride and PMA, enhancement was characterized by a decrease in the lag from stimulation to initiation of superoxide release and by an increase in the rate of superoxide generation--representing faster activation and increased activity of O2- generating enzyme, respectively. Chemotactic concentrations of casein, normal serum, and casein-treated serum enhanced the activity, but not the rate of activation, of the fluoride- stimulated superoxide generating system. This effect on activity was not so impressive as that obtained with FMLP or ZAS. The mechanisms by which FMLP enhanced responsiveness to fluoride and PMA were found to be different. Optimal enhancement for fluoride-stimulated responses required extracellular Ca++. Extracellular glucose, but not extracellular Ca++, was required for enhancement of FMLP of PMA- stimulated responses. A similar glucose requirement could not be demonstrated for chemotactic peptide enhancement of the superoxide- generating system stimulated by fluoride. Fluoride and PMA apparently activate the neutrophil O2- generating enzyme by pathways that are not identical. However, responsiveness of the enzyme to both agents is susceptible to modulation by cellular responses to chemotactic peptides.

scholarly journals Protein phosphatase inhibitors okadaic acid and calyculin A alter cell shape and F-actin distribution and inhibit stimulus-dependent increases in cytoskeletal actin of human neutrophils

Blood ◽  
1992 ◽  
Vol 80 (11) ◽  
pp. 2911-2919 ◽  
Author(s):  
P Kreienbuhl ◽  
H Keller ◽  
V Niggli
Keyword(s):  
Okadaic Acid ◽  
Human Neutrophils ◽  
Resting Cells ◽  
Calyculin A ◽  
Chemotactic Peptide ◽  
Phosphatase Inhibitors ◽  
Protein Phosphatase Inhibitors ◽  
Actin Localization ◽  
Shape Changes

Abstract The phosphatase inhibitors okadaic acid and calyculin A were found to elicit or to modify several neutrophil responses, suggesting that dephosphorylation plays a regulatory role. The concentrations of okadaic acid (> or = 1 mumol/L) that were effective on neutrophil functions (shape changes and marginal stimulation of pinocytosis) were shown to stimulate the incorporation of 32PO4 into many neutrophil proteins several-fold. Calyculin A was effective at 50-fold lower concentrations. In the presence of the inhibitors, the cells exhibited a nonpolar shape and the polarization response induced by chemotactic peptide was inhibited. Both phosphatase inhibitors also induced the association of F-actin with the cell membrane. A steady-state phosphatase activity is thus involved in maintaining shape and F-actin localization of resting cells. Inhibitors alone had no significant effect on the amount of cytoskeleton-associated actin. The increase in cytoskeletal actin observed at 30 minutes of stimulation with phorbol ester or 5 to 30 minutes of stimulation with chemotactic peptide, however, was abolished by okadaic acid or calyculin A, suggesting an important role of a phosphatase. In contrast, the early increase in cytoskeleton-associated actin observed at 1 minute of stimulation with peptide was not affected. This finding indicates that the increased association of actin with the cytoskeleton in the early and the later stages of neutrophil activation may be mediated by different signalling pathways.

scholarly journals The chlorinating potential of the human monocyte

Blood ◽  
1983 ◽  
Vol 62 (3) ◽  
pp. 645-651 ◽  
Author(s):  
MB Lampert ◽  
SJ Weiss
Keyword(s):  
Phorbol Myristate Acetate ◽  
Cell Concentration ◽  
Human Monocyte ◽  
Human Neutrophils ◽  
Human Monocytes ◽  
Taurine Chloramine ◽  
Myristate Acetate ◽  
Opsonized Zymosan ◽  
Nitrobenzoic Acid ◽  
Characteristic Absorption Peak

Abstract Human monocytes incubated with phorbol myristate acetate (PMA) or opsonized zymosan particles can chlorinate the beta-amino acid taurine to its monochloramine derivative. Taurine monochloramine can then be quantitated by its ability to oxidize 5-thio-2-nitrobenzoic acid to its disulfide or by its characteristic absorption peak at 252 nm. Stimulated, but not resting, monocytes chlorinated taurine by a process dependent on time, cell concentration, and pH. The formation of taurine chloramine by stimulated monocytes could be inhibited by catalase, azide, or cyanide, was unaffected by superoxide dismutase, and was stimulated by exogenous myeloperoxidase. Thus, taurine chloramine generation by human monocytes appeared dependent on both H2O2 and myeloperoxidase. Compared to human neutrophils, the monocyte could generate similar amounts of chloramine when stimulated with phorbol myristate acetate, but far less if opsonized zymosan particles were used as the trigger. Based on the known ability of the H2O2- myeloperoxidase-Cl- system to generate free HOCl, it would seem that this oxidant is the most likely species responsible for the monocyte- mediated chlorination reactions. Thus, we have used a simple quantitative assay to demonstrate the ability of the human monocyte to generate large quantities of a highly reactive and toxic oxygen metabolite.

Suppressive action of cobalt on exocytosis and respiratory burst in neutrophils

1989 ◽  
Vol 257 (5) ◽  
pp. C859-C864 ◽  
Author(s):  
J. G. Elferink ◽  
M. Deierkauf
Keyword(s):  
Plasma Membrane ◽  
Phorbol Myristate Acetate ◽  
Respiratory Burst ◽  
Cytochalasin B ◽  
Superoxide Production ◽  
Co2 Activation ◽  
Chemotactic Peptide ◽  
Myristate Acetate ◽  
Intracellular Target ◽  
Suppressive Action

Activation of exocytosis and respiratory burst in rabbit neutrophils by the chemotactic peptide fMet-Leu-Phe is inhibited by Co2+. Inhibition is antagonized by extracellular Ca2+ and is dependent on the time of preincubation of cells with Co2+ before addition of activator. Co2+ inhibits the enhancement of 45Ca association that occurs during activation with fMet-Leu-Phe. Interference with Ca2+ translocation across the plasma membrane by Co2+ is probably not the cause of inhibition of neutrophil activation, because activation in the absence of extracellular Ca2+ is inhibited by Co2+. Activation of neutrophils by phorbol myristate acetate is inhibited at higher Co2+ concentrations than activation by fMet-Leu-Phe. Inhibition of the superoxide production by Co2+ occurs both in the presence or in the absence of cytochalasin B. Fluorescence of neutrophils loaded with quin2 is diminished by Co2+, indicating that Co2+ had entered into the cytoplasm. The results are compatible with the view that Co2+ inhibits exocytosis and respiratory burst in neutrophils by an interaction with a Ca2+-dependent intracellular target.

Comparison of 1-oleoyl-2-acetyl-glycerol and phorbol myristate acetate as secretagogues for human neutrophils

1986 ◽  
Vol 64 (8) ◽  
pp. 1149-1152 ◽  
Author(s):  
Kenneth Wong ◽  
Christine Chew
Keyword(s):  
Phorbol Myristate Acetate ◽  
Cellular Responses ◽  
Current Evidence ◽  
Human Neutrophils ◽  
Myristate Acetate ◽  
First Order ◽  
Regulatory Constraints ◽  
Kinase C ◽  
Rate Of Decay ◽  
The Stability

Cellular responses induced in human neutrophils by the synthetic diacylglycerol, 1-oleoyl-2-acetyl-glycerol (OAG), paralleled those induced by phorbol myristate acetate (PMA). Like PMA, OAG caused the preferential release of enzymes from specific granules and promoted superoxide (O2−) generation. The efficacy of OAG was similar to that for PMA, but its potency was lower by four orders of magnitude. First derivative kinetic analysis showed that rates of O2− generation elicited by PMA decayed exponentially in a first order manner; the half life was found to be 21 ± 6 min. Results obtained in studies carried out with high OAG concentrations were similar except that after 40 min, the rate of decay increased and became complex order. This difference was attributed to the greater susceptibility of OAG to metabolic alteration, and was reflected in the NADPH oxidase activity of granule rich membrane fractions (GRF) of cells stimulated for 90 min with PMA or OAG. It was found that the O2− generating activity of the PMA treated GRF was significantly greater than that for the OAG treated fraction. Current evidence indicates that cellular responses arise from direct activation of protein kinase C by PMA-OAG. The stability of this complex and the bypassing of normal regulatory constraints may account for the relative longevity of the PMA–OAG O2− respiratory burst.

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