Simultaneous presence of platelet activating factor, leukotriene B4, prostaglandin F1α and F2α in the supernatant of human neutrophils treated with phospholipase A2 of human monocytes

1989 ◽  
Vol 67 (3) ◽  
pp. 123-125 ◽  
Author(s):  
S. Sipka ◽  
Z. Dinya ◽  
P. Gergely ◽  
T. Farkas ◽  
G. Szegedi
Keyword(s):  
Phospholipase A2 ◽  
Platelet Activating Factor ◽  
Leukotriene B4 ◽  
Human Neutrophils ◽  
Human Monocytes ◽  
Simultaneous Presence

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 Induction of cytosolic phospholipase A2 activity by phosphatidic acid and diglycerides in permeabilized human neutrophils: interrelationship between phospholipases D and A2

1997 ◽  
Vol 322 (2) ◽  
pp. 353-363 ◽  
Author(s):  
Sue A. BAULDRY ◽  
Rhonda E. WOOTEN
Keyword(s):  
Phosphatidic Acid ◽  
Phospholipase A2 ◽  
Second Messengers ◽  
Platelet Activating Factor ◽  
Human Neutrophils ◽  
Partial Restoration ◽  
Permeabilized Cells ◽  
Cpla2 Activation ◽  
Factor Α ◽  
Cytosolic Pla2

Relationships between phospholipases are poorly understood, but phosphatidic acid (PA) and diglycerides (DGs), produced by phospholipase D (PLD) and phosphatidate phosphohydrolase actions, might function as second messengers coupling cell stimulation to cellular responses. This study investigates the role of PLD-mediated PA and DG formation in inducing phospholipase A2 (PLA2) activity in intact human neutrophils (PMNs) and in PMNs permeabilized with Staphylococcus aureusα-toxin. PMNs were labelled with [3H]arachidonic acid (AA) to assess AA release and metabolism and diacylglycerol formation, or with [3H]1-O-hexadecyl-2-lyso-glycerophosphatidylcholine for the determination of platelet-activating factor (PAF), PA and alkylacylglycerol production. In intact PMNs primed with tumour necrosis factor α before stimulation with N-formyl-Met-Leu-Phe, AA release and metabolism and PAF formation increased in parallel with enhanced PA and DG formation, and inhibition of PA and DG production led to a decrease in both AA release and PAF accumulation. In α-toxin-permeabilized PMNs, AA release and PAF production result from the specific activation of cytosolic PLA2 (cPLA2). In this system, PA and DG formation were always present when cPLA2 activation occurred; blocking PA and DG production inhibited AA release and PAF accumulation. Adding either PA or DG back to permeabilized cells (with endogenous PA and DG formation blocked) led to a partial restoration of AA release and PAF formation; a combination of PA and DGs reconstituted full cPLA2 activity. These results strongly suggest that products of PLD participate in activating cPLA2 in PMNs.

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.

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.

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