scholarly journals Regulation of macrophage eicosanoid production by hydroperoxy-and hydroxy-eicosatetraenoic acids

1986 ◽  
Vol 233 (1) ◽  
pp. 199-206 ◽  
Author(s):  
J L Humes ◽  
E E Opas ◽  
M Galavage ◽  
D Soderman ◽  
R J Bonney
Keyword(s):  
Cell Culture ◽  
Arachidonic Acid ◽  
Peritoneal Macrophages ◽  
Lipoxygenase Pathway ◽  
Reversible Inhibitors ◽  
Irreversible Inhibitors ◽  
Intracellular Regulation ◽  
Macrophage Populations ◽  
Mouse Peritoneal Macrophages ◽  
Hydroxyeicosatetraenoic Acids

Resident mouse peritoneal macrophages when exposed to zymosan during the first day of cell culture synthesize and secrete large amounts of prostaglandin E2 (PGE2) and leukotriene C4 (LTC4), the respective products of cyclo-oxygenase- and 5-lipoxygenase-catalysed oxygenations of arachidonic acid. Under these conditions of cell stimulation only small amounts of hydroxyeicosatetraenoic acids (HETEs) are concomitantly produced. However, exogenously added arachidonic acid is metabolized to large amounts of 12- and 15-HETE and only relatively small amounts of PGE2. No LTC4 is formed under these conditions. In contrast, resident mouse peritoneal macrophages in cell culture for 4 days synthesized less PGE2 and LTC4 when exposed to zymosan. However, these macrophage populations continue to synthesize 12-HETE from exogenously added arachidonic acid. Zymosan induced the secretion of a lysosomal enzyme, N-acetyl-beta-glucosaminidase, equally in both 1- and 4-day cultures. Both 12- and 15-hydroperoxyeicosatetraenoic acids (HPETEs), the precursors of 12- and 15-HETE, were found to be irreversible inhibitors of the cyclo-oxygenase pathway and reversible inhibitors of the 5-lipoxygenase pathway in macrophages. 15-HETE were found to be reversible inhibitors of both pathways. Thus the oxidation of arachidonic oxidation of arachidonic acid to both prostaglandins and leukotrienes may be under intracellular regulation by products of 12- and 15-lipoxygenases.

scholarly journals Dynamics of leukotriene C production by macrophages.

1980 ◽  
Vol 152 (5) ◽  
pp. 1236-1247 ◽  
Author(s):  
C A Rouzer ◽  
W A Scott ◽  
A L Hamill ◽  
Z A Cohn
Keyword(s):  
Time Course ◽  
Culture Medium ◽  
Peritoneal Macrophages ◽  
Experimental Conditions ◽  
Silicic Acid Chromatography ◽  
Pg Release ◽  
Antigen Antibody ◽  
Mouse Peritoneal Macrophages ◽  
Hydroxyeicosatetraenoic Acids

A method for the radiochemical assay of LTC production by mouse peritoneal macrophages in vitro is presented. The method involves labeling macrophages in culture with [5,6,8,9,11,12,14,15-3H]20:4 followed by stimulation of arachidonic acid (20:4) release under the experimental conditions desired. Radiolabeled leukotriene C (LTC) is recovered from the culture medium by extraction and silicic acid chromatography in 40% yield with full retention of biological activity. Because this LTC is radiochemically pure, the quantity of LTC release may be estimated from the amount of radioactivity in the sample. Use of the radioassay to study parameters affecting LTC synthesis by macrophages indicated that the time course of LTC synthesis and its relationship to the dose of a phagocytic stimulus (zymosan) were very similar to those of prostaglandin (PG) release. LTC release was also similar to that of PG in that lower levels of both metabolites were produced by Corynebacterium parvum-elicited macrophages than by resident cells. Finally, LTC release was stimulated in response to a challenge with antigen-antibody complexes, but lower maximal levels were attained than those with zymosan. The data presented here are consistent with the hypothesis that challenge of macrophages with a phagocytic stimulus leads to the release of 20:4 by an inducible phospholipase. Cyclooxygenase and lipoxygenase then compete for the released 20:4, leading to the production of PG, hydroxyeicosatetraenoic acids, and LTC.

Transformation of arachidonic acid into monohydroxy-eicosatetraenoic acids by mouse peritoneal macrophages

Lipids ◽  
1981 ◽  
Vol 16 (7) ◽  
pp. 518-524 ◽  
Author(s):  
Hélène Rabinovitch ◽  
Jacqueline Durand ◽  
Michel Rigaud ◽  
Francois Mendy ◽  
Jean-Christian Breton
Keyword(s):  
Arachidonic Acid ◽  
Peritoneal Macrophages ◽  
Mouse Peritoneal Macrophages

Action Of Ticlopidine On The Oxygenated Metabolism Of Arachidonic Acid In The Mouse Peritoneal Macrophages

1981 ◽  
Author(s):  
M Rigaud ◽  
H Rabinovitch ◽  
J Durand ◽  
J C Breton ◽  
G Rigaud
Keyword(s):  
Arachidonic Acid ◽  
Mammalian Cells ◽  
Culture Medium ◽  
Eicosatrienoic Acid ◽  
Peritoneal Macrophages ◽  
Membrane Phospholipids ◽  
Glass Capillary ◽  
Drug Concentrations ◽  
High Concentrations ◽  
Mouse Peritoneal Macrophages

When ticlopidine is added to macrophages cultures, in the absence of exogenous arachidonic acid, there is a production of both“prostanoids” and“eicosanoids” in the culture medium. These products have been measured using glass capillary gas chomatography prior to multiple ion mass spectrometry. The quantitative determinations are made 5, 15, 25, 35 and 45 minutes after the drug was added to the macrophages cultures. The three drug concentrations used (10-4M, 5.10-5M and 2.5 10-5M) induce a liberation of 6-keto-PGF1α in the culture medium. As in our system 6-keto-PGF1α seems to be the major metabolite of PGI2, ticlopidine is likely to act by releasing important quantities of PGI2 in macrophages. These results suggest an increase of liberation of the endogenous arachidonic acid from the membrane phospholipids of the macrophages or a lack in the acyltransferase system of the cell membranes. The lipoxygenasic pathway was also studied. When ticlopidine is added to macrophages, two products are liberated: . 12-HETE as measured by single iondetection . and 10-hydroxy-ll-12-epoxy, -5, 8, 14-eicosatrienoic acid which comes from an internal rearrangement of the 12-HPETE. In these results, there is a discrepancy between the fact that ticlopidine increases the concentration of 12-HETE and surely its precursor the 12-HPETE and the fact that the synthesis of PGI2 is not inhibited by these high concentrations of hydroperoxide. To understand this phenomenon we studied the production of hydroperoxide when arachidonic acid is incubated with soybean lipoxygenase. When ticlopidine (10-4M) is added to the reaction mixture (AA + soy lipoxygenase) there is an increase of the initial rate and an extent of the reaction as if the enzyme irreversible deactivation was postponed. Ticlopidine could act by suppressing the classical inhibition of PGI2 synthetase by hydroperoxides, in particular 12-HPETE and 15-HPETE, both produced by mammalian cells.

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