Transcellular metabolism of endogenous arachidonic acid during platelet-neutrophil interactions

1988 ◽  
Vol 20 ◽  
pp. 78
Author(s):  
D. Caruso ◽  
P. Maderna ◽  
S. Colli ◽  
H. Chi ◽  
G. Galli ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Transcellular Metabolism

scholarly journals Transcellular metabolism of arachidonic acid: increased platelet thromboxane generation in the presence of activated polymorphonuclear leukocytes

Blood ◽  
1992 ◽  
Vol 80 (2) ◽  
pp. 447-451
Author(s):  
N Maugeri ◽  
V Evangelista ◽  
P Piccardoni ◽  
G Dell'Elba ◽  
A Celardo ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Polymorphonuclear Leukocytes ◽  
Cytochalasin B ◽  
Present Report ◽  
Experimental System ◽  
Total Radioactivity ◽  
Cathepsin G ◽  
Eglin C ◽  
Human Polymorphonuclear Leukocytes ◽  
Transcellular Metabolism

Human polymorphonuclear leukocytes (PMN) activated by n-formyl- methionyl-leucyl-phenylalanine (fMLP), in the presence of cytochalasin B, are able to induce activation of coincubated autologous platelets “via” cathepsin G released from the azurophilic granules. However, thromboxane (Tx) B2 production in this system cannot be completely explained by cathepsin G-stimulated platelet arachidonate metabolism. Indeed, the amount of TxB2 found in supernatants of platelet/PMN suspensions challenged with 1 mumol/L fMLP was twofold to fourfold higher than that measured when platelets were stimulated by supernatants from fMLP-activated PMN. In the present report, we analyzed the possibility that PMN-induced TxB2 production in this system is the result of transcellular metabolism of arachidonic acid (AA) between fMLP-activated PMN and cathepsin G-stimulated platelets. 3H-AA-labeled PMN were used to test if a transfer of AA or metabolite(s) occur from PMN to platelets. Our results showed that: (1) 3H-TxB2 and 3H-12-HHT are synthesized when 3H-AA-labeled PMN are activated mixed to unlabeled platelets; (2) total radioactivity released by fMLP-stimulated PMN is increased in the presence of platelets, whereas the membrane content of unesterified 3H-AA is reduced; (3) platelet cyclooxygenase inhibition completely prevents 3H- TxB2 synthesis; and (4) inhibition of cathepsin G-induced platelet activation with the antiprotease eglin C blocks the formation of 3H- TxB2. These data show that in the experimental system used, platelets use PMN-derived unmetabolized AA to synthesize TxB2.

scholarly journals Cryptococcal Lipid Metabolism: Phospholipase B1 Is Implicated in Transcellular Metabolism of Macrophage-Derived Lipids

2006 ◽  
Vol 6 (1) ◽  
pp. 37-47 ◽  
Author(s):  
Lesley C. Wright ◽  
Rosemary M. Santangelo ◽  
Ranjini Ganendren ◽  
Jackie Payne ◽  
Julianne T. Djordjevic ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Carbon Source ◽  
Stationary Phases ◽  
Eukaryotic Cell ◽  
Human Macrophage ◽  
Wild Type ◽  
Dipalmitoyl Phosphatidylcholine ◽  
Eicosanoid Production ◽  
Energy Dependent ◽  
Transcellular Metabolism

ABSTRACT Cryptococci survive and replicate within macrophages and can use exogenous arachidonic acid for the production of eicosanoids. Phospholipase B1 (PLB1) has a putative, but uninvestigated, role in these processes. We have shown that uptake and esterification of radiolabeled arachidonic, palmitic, and oleic acids by the Cryptococcus neoformans var. grubii H99 wild-type strain and its PLB1 deletion mutant strain (the Δplb1 strain) are independent of PLB1, except under hyperosmolar stress. Similarly, PLB1 was required for metabolism of 1-palmitoyl lysophosphatidylcholine (LysoPC), which is toxic to eukaryotic cell membranes, under hyperosmolar conditions. During both logarithmic and stationary phases of growth, the physiologically relevant phospholipids, dipalmitoyl phosphatidylcholine (DPPC) and dioleoyl phosphatidylcholine, were taken up and metabolized via PLB1. Exogenous DPPC did not enhance growth in the presence of glucose as a carbon source but could support it for at least 24 h in glucose-free medium. Detoxification of LysoPC by reacylation occurred in both the H99 wild-type and the Δplb1 strains in the presence of glucose, but PLB1 was required when LysoPC was the sole carbon source. This indicates that both energy-independent (via PLB1) and energy-dependent transacylation pathways are active in cryptococci. Phospholipase A1 activity was identified by PLB1-independent degradation of 1-palmitoyl-2-arachidonoyl phosphatidylcholine, but the arachidonoyl LysoPC formed was not detoxified by reacylation. Using the human macrophage-like cell line THP-1, we demonstrated the PLB1-dependent incorporation of macrophage-derived arachidonic acid into cryptococcal lipids during cryptococcus-phagocyte interaction. This pool of arachidonate can be sequestered for eicosanoid production by the fungus and/or suppression of host phagocytic activity, thus diminishing the immune response.

scholarly journals Transcellular metabolism of arachidonic acid: increased platelet thromboxane generation in the presence of activated polymorphonuclear leukocytes

Blood ◽  
1992 ◽  
Vol 80 (2) ◽  
pp. 447-451 ◽  
Author(s):  
N Maugeri ◽  
V Evangelista ◽  
P Piccardoni ◽  
G Dell'Elba ◽  
A Celardo ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Polymorphonuclear Leukocytes ◽  
Cytochalasin B ◽  
Present Report ◽  
Experimental System ◽  
Total Radioactivity ◽  
Cathepsin G ◽  
Eglin C ◽  
Human Polymorphonuclear Leukocytes ◽  
Transcellular Metabolism

Abstract Human polymorphonuclear leukocytes (PMN) activated by n-formyl- methionyl-leucyl-phenylalanine (fMLP), in the presence of cytochalasin B, are able to induce activation of coincubated autologous platelets “via” cathepsin G released from the azurophilic granules. However, thromboxane (Tx) B2 production in this system cannot be completely explained by cathepsin G-stimulated platelet arachidonate metabolism. Indeed, the amount of TxB2 found in supernatants of platelet/PMN suspensions challenged with 1 mumol/L fMLP was twofold to fourfold higher than that measured when platelets were stimulated by supernatants from fMLP-activated PMN. In the present report, we analyzed the possibility that PMN-induced TxB2 production in this system is the result of transcellular metabolism of arachidonic acid (AA) between fMLP-activated PMN and cathepsin G-stimulated platelets. 3H-AA-labeled PMN were used to test if a transfer of AA or metabolite(s) occur from PMN to platelets. Our results showed that: (1) 3H-TxB2 and 3H-12-HHT are synthesized when 3H-AA-labeled PMN are activated mixed to unlabeled platelets; (2) total radioactivity released by fMLP-stimulated PMN is increased in the presence of platelets, whereas the membrane content of unesterified 3H-AA is reduced; (3) platelet cyclooxygenase inhibition completely prevents 3H- TxB2 synthesis; and (4) inhibition of cathepsin G-induced platelet activation with the antiprotease eglin C blocks the formation of 3H- TxB2. These data show that in the experimental system used, platelets use PMN-derived unmetabolized AA to synthesize TxB2.

Increased Response to Arachidonic Acid and U-46619 and Resistance to Inhibitory Prostaglandins in Patients with Chronic Myeloproliferative Disorders

1988 ◽  
Vol 59 (01) ◽  
pp. 073-076 ◽  
Author(s):  
Sergio Cortelazzo ◽  
Monica Galli ◽  
Donatella Castagna ◽  
Piera Viero ◽  
Giovanni de Gaetano ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Arachidonic Acid ◽  
Platelet Aggregation ◽  
Myeloproliferative Disorders ◽  
Bone Marrow Stem Cell ◽  
Healthy Controls ◽  
Aggregation Response ◽  
Thrombotic Complications ◽  
Cyclic Endoperoxide ◽  
Marrow Stem Cell

SummaryIn patients with myeloproliferative disorders (MPD) a group of related diseases of the bone marrow stem cell and recurrent haemorrhagic and/or thrombotic complications, the production of aggregating prostaglandins (PGs) may be normal or slightly reduced, while PGI2 production is normal. However, MPD platelet sensitivity to antiaggregatory PGs is still unknown.We studied the potency of PGD2, PGI2 and PGEi as inhibitors of platelet aggregation induced by threshold aggregating concentrations of arachidonic acid and U-46619-analogue of the cyclic endoperoxide PGH2 in 20 patients with MPD in comparison with healthy controls, with the aim of evaluating the sensitivity of MPD platelets to antiaggregatory PGs. In these patients platelet prostanoid metabolism was normal. However, the functional response of platelets to aggregating and antiaggregating prostanoids was shifted towards potentially increased platelet aggregation response. These findings could have a clinical relevance in view of the haemostatic and thrombotic complications so frequent in MPD.

Dose-Response Aggregometry in Maternal/Neonatal Platelets

1988 ◽  
Vol 60 (02) ◽  
pp. 314-318 ◽  
Author(s):  
A M A Gader ◽  
H Bahakim ◽  
F A Jabbar ◽  
A L Lambourne ◽  
T H Gaafar ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Dose Response ◽  
Lag Phase ◽  
Phase Slope ◽  
Multiple Doses ◽  
Nonpregnant Adult ◽  
Aggregation Of Platelets

SummaryThe aggregation of platelets collected from maternal/neonatal pairs (n = 240) at the time of childbirth, was studied in response to multiple doses of ADP, collagen, arachidonic acid and ristocetin. Similar responses were obtained from healthy nonpregnant adult controls for comparison. The lag phase, slope of the aggregation curves as well as maximum aggregation (MA%) were recorded and analysed. Neonatal and adult platelets exhibited more enhanced responses to decreasing doses of ADP, arachidonic acid and ristocetin, than maternal platelets. These enhanced responses were exhibited more consistantly in the slopes of the aggregation curves than in MA%. Although neonatal platelets have shown longer lag phase in their responses to collagen, the rate of the aggregation reaction was significantly faster than maternal platelets, with no differences in MA%. These results contradict many previous reports suggesting impaired aggregation responses of neonatal platelets to these agonist. The possible reasons for these contradictions were discussed.

Involvement of Cyclooxygenase- and Lipoxygenase-Mediated Conversion of Arachidonic Acid in Controlling Human Vascular Smooth Muscle Cell Proliferation

1990 ◽  
Vol 63 (02) ◽  
pp. 291-297 ◽  
Author(s):  
Herm-Jan M Brinkman ◽  
Marijke F van Buul-Worteiboer ◽  
Jan A van Mourik
Keyword(s):  
Cell Proliferation ◽  
Arachidonic Acid ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Smooth Muscle Cell ◽  
Muscle Cell ◽  
Vascular Smooth Muscle Cell ◽  
Muscle Cells ◽  
Smooth Muscle Cell Proliferation

SummaryWe observed that the growth of human umbilical arterysmooth muscle cells was inhibited by the phospholipase A2 inhibitors p-bromophenacylbromide and mepacrine. Thesefindings suggest that fatty acid metabolism might be integrated in the control mechanism of vascular smooth muscle cell proliferation. To identify eicosanoids possibly involved in this process, we studied both the metabolism of arachidonic acid of these cells in more detail and the effect of certain arachidonic acid metabolites on smooth muscle cells growth. We found no evidence for the conversion of arachidonic acid via the lipoxygenase pathway. In contrast, arachidonic acid was rapidly converted via the cyclooxy-genase pathway. The following metabolites were identified: prostaglandin E2 (PGE2), 6-keto-prostaglandin F1α (6-k-PGF1α), prostaglandin F2α (PGF2α), 12-hydroxyheptadecatrienoic acid (12-HHT) and 11-hydroxyeicosatetetraenoic acid (11-HETE). PGE2 was the major metabolite detected. Arachidonic acid metabolites were only found in the culture medium, not in the cell. After synthesis, 11-HETE was cleared from the culture medium. We have previously reported that PGE2 inhibits the serum-induced [3H]-thymidine incorporation of growth-arrested human umbilical artery smooth muscle cells. Here we show that also 11-HETEexerts this inhibitory property. Thus, our data suggeststhat human umbilical artery smooth muscle cells convert arachidonic acid only via the cyclooxygenase pathway. Certain metabolites produced by this pathway, including PGE2 and 11-HETE, may inhibit vascular smooth muscle cell proliferation.

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