scholarly journals Accumulation of phosphatidic acid mass and increased de novo synthesis of glycerolipids in platelet-activating-factor-activated human neutrophils

1991 ◽  
Vol 280 (3) ◽  
pp. 625-629 ◽  
Author(s):  
J S Tou ◽  
J R Jeter ◽  
C P Dola ◽  
S Venkatesh
Keyword(s):  
Phosphatidic Acid ◽  
Cytochalasin B ◽  
De Novo ◽  
Platelet Activating Factor ◽  
Human Neutrophils ◽  
Total Lipid Extract ◽  
De Novo Synthesis ◽  
Predominant Species ◽  
Rapid Accumulation ◽  
Mass Accumulation

Incubation of human neutrophils with 100 nM-platelet-activating factor (PAF) but without cytochalasin B resulted in a rapid (5 s) accumulation (1.6-fold) of phosphatidic acid (PtdOH) mass. The increased PtdOH mass reached a maximum (2.8-fold) at 1 min and remained elevated (1.7-fold) at 10 min. No methylamine-stable lyso-PtdOH was detectable in the total lipid extract from control or from PAF-activated cells, suggesting that diacyl-PtdOH was the predominant species. In PAF-activated cells, changes in 1,2-diacylglycerol (DG) mass were not detectable at 5 or 15 s. Increased DG mass (1.7-fold) was detected between 30 s and 2 min, but then it declined to basal levels by 10 min. PAF enhanced [3H]glycerol incorporation into PtdOH and DG by 2- and 3-fold respectively during 1-10 min incubations. PAF also increased the radioactivity but not the mass of phosphatidylinositol and of choline glycerophospholipid by 8-fold and 4-fold respectively at 10 min. In addition, PAF-activated cells showed increased (2-fold) glycerol incorporation into triacylglycerol. These results demonstrate that PAF enhances rapid accumulation of diacyl-PtdOH mass, and that increased de novo synthesis may contribute to PtdOH mass accumulation.

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 Intracellular localization and de novo synthesis of FcRIII in human neutrophil granulocytes

Blood ◽  
1990 ◽  
Vol 75 (1) ◽  
pp. 144-151 ◽  
Author(s):  
CR Jost ◽  
TW Huizinga ◽  
R de Goede ◽  
JA Fransen ◽  
PA Tetteroo ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Golgi Complex ◽  
De Novo ◽  
Intracellular Localization ◽  
Human Neutrophils ◽  
Neutrophil Granulocytes ◽  
Metabolic Labeling ◽  
De Novo Synthesis ◽  
Double Labeling ◽  
Microscopic Studies

Abstract Immunoelectron microscopic studies in human neutrophils showed that FcRIII was present on the plasma membrane, in the Golgi complex, and in many small vesicles (120 to 180 nm). FcRIII was not found in specific or azurophilic granules as shown by immunogold double-labeling experiments, visualizing both FcRIII and either lactoferrin (a marker of specific granules) or myeloperoxidase (a marker for azurophilic granules). Because the occurrence of FcRIII in the Golgi complex suggested that biosynthesis of this receptor occurs in these cells, metabolic labeling experiments were performed. Immunoprecipitation of FcRIII from NP-40 lysates of cells labeled with 35S-methionine showed a diffuse 50- to 70-Kd band corresponding with the band noted after immunoprecipitation of FcRIII from surface iodinated cells. These findings show that de novo synthesis of FcRIII occurs in neutrophils and suggest that at least some of the small vesicles containing FcRIII derive from the Golgi complex and thus are involved in transport of newly synthesized FcRIII to the plasma membrane.

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.

PLATELET-ACTIVATING FACTOR INDUCES DE NOVO SYNTHESIS OF MTOR IN TERMINALLY DIFFERENTIATED POLYMORPHONUCLEAR LEUKOCYTES.

2007 ◽  
Vol 55 (1) ◽  
pp. S143
Author(s):  
F. J. Rubner ◽  
M. J. Cody ◽  
G. A. Zimmerman ◽  
A. S. Weyrich ◽  
H. R. Hill ◽  
...  
Keyword(s):  
Polymorphonuclear Leukocytes ◽  
De Novo ◽  
Platelet Activating Factor ◽  
De Novo Synthesis

SEVERELY IMPAIRED SYNTHESIS OF PLATELET ACTIVATING FACTOR IN CHONDRO DYSPLASIA PUNCTATA RHIZOMELIA PATIENTS

1987 ◽  
Author(s):  
A Sturk ◽  
M C L Schaap ◽  
A Prins Heymans ◽  
J W ten Cate ◽  
R J A Wanders ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Platelet Activation ◽  
Normal Control ◽  
De Novo ◽  
Platelet Activating Factor ◽  
Lipid Synthesis ◽  
Ionophore A23187 ◽  
De Novo Synthesis ◽  
Normal Platelet ◽  
Normal Controls

The first steps of the de novo synthesis of alkoxyether lipids, like plasmalogens and platelet activating factor (PAF) are localized in the peroxisome. We have previously reported the severely impaired PAF synthesis in Zellweger patients. These patients lack cytochemically detectable peroxisomes, and have a severely impaired alkoxyether lipid synthesis. However, chondro dysplasia punctata (CDP) patients have also been shown to have an impaired alkoxyether lipid synthesis. We therefore investigated PAF synthesis in CDP patients.Platelets and leucocytes were isolated from 3 CDP patients. Leucocytes from normal controls produced 4678 ± 2033 pMoles PAF/10 cells (n=6, range 1698-7058) when optimally stimulated with Ca2+-ionophore A23187. Normal control platelets produced 0.6 ± 0.3 pMoles PAF/10 cells (n=6, range 0.3-1.0) when optimally stimulated with thrombin. PAF synthesis by the leucocytes of the patients was severely reduced, but detectable. Leucocytes from patient 1, 2 and 3 synthesized 9, 660 and 325 pMoles PAF/10 cells respectively. Platelets from the patients 1, 2 and 3 synthesized 0.1, 0.2 and 0.2 pMoles PAF/10 cells respectively.Platelet aggregation, induced by ADP, PAF, or thrombin (also in the presence of inhibitors of the first and second pathway of platelet activation) was normal.We conclude that PAF synthesis is severely impaired in leucocytes and reduced in platelets from CDP patients. The residual platelet PAF synthesis may suffice to warrant normal platelet functioning.

Pattern of Incorporation of 32P into the Phospholipids of the Rat Tapeworm Hymenolepis diminuta

1971 ◽  
Vol 49 (11) ◽  
pp. 1209-1212 ◽  
Author(s):  
R. A. Webb ◽  
D. F. Mettrick
Keyword(s):  
Fatty Acid ◽  
Phosphatidic Acid ◽  
De Novo ◽  
Hymenolepis Diminuta ◽  
De Novo Synthesis ◽  
Major Pathway ◽  
Acid Incorporation ◽  
Fatty Acid Incorporation

The incorporation of 32P-orthophosphate into the phospholipids of H. diminuta was followed for up to 4 h in vitro. The rates and patterns of incorporation of 32P into phosphatidc acid, phosphoinositide, phosphatidylserine, lecithin, lysolecithin, and phosphatidylethanolamine plus cardiolipin indicated that H. diminuta possesses mechanisms for the de novo synthesis of these phospholipids. The major pathway utilized by H. diminuta in fatty acid incorporation was via phosphatidic acid.

scholarly journals Intracellular localization and de novo synthesis of FcRIII in human neutrophil granulocytes

Blood ◽  
1990 ◽  
Vol 75 (1) ◽  
pp. 144-151
Author(s):  
CR Jost ◽  
TW Huizinga ◽  
R de Goede ◽  
JA Fransen ◽  
PA Tetteroo ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Golgi Complex ◽  
De Novo ◽  
Intracellular Localization ◽  
Human Neutrophils ◽  
Neutrophil Granulocytes ◽  
Metabolic Labeling ◽  
De Novo Synthesis ◽  
Double Labeling ◽  
Microscopic Studies

Immunoelectron microscopic studies in human neutrophils showed that FcRIII was present on the plasma membrane, in the Golgi complex, and in many small vesicles (120 to 180 nm). FcRIII was not found in specific or azurophilic granules as shown by immunogold double-labeling experiments, visualizing both FcRIII and either lactoferrin (a marker of specific granules) or myeloperoxidase (a marker for azurophilic granules). Because the occurrence of FcRIII in the Golgi complex suggested that biosynthesis of this receptor occurs in these cells, metabolic labeling experiments were performed. Immunoprecipitation of FcRIII from NP-40 lysates of cells labeled with 35S-methionine showed a diffuse 50- to 70-Kd band corresponding with the band noted after immunoprecipitation of FcRIII from surface iodinated cells. These findings show that de novo synthesis of FcRIII occurs in neutrophils and suggest that at least some of the small vesicles containing FcRIII derive from the Golgi complex and thus are involved in transport of newly synthesized FcRIII to the plasma membrane.

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