Effect of cholesterol enrichment on 12-hydroxyeicosatetraenoic acid metabolism by mouse peritoneal macrophages

The metabolism of 12-hydroxyeicosatetraenoic acid (12-HETE) was investigated in mouse peritoneal macrophages enriched in cholesterol by incubation with acetylated low density lipoproteins. After incubating with labeled arachidonic acid, cholesterol-rich cells released more 12-HETE into the medium th...

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Main Authors: S N Mathur, F J Field
Format: Article
Language:English
Published: Elsevier 1987-10-01
Series:Journal of Lipid Research
Online Access:http://www.sciencedirect.com/science/article/pii/S0022227520386016
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spelling doaj-b2b2db0999194806abc52e78f95880c92021-04-25T04:20:04ZengElsevierJournal of Lipid Research0022-22751987-10-01281011661176Effect of cholesterol enrichment on 12-hydroxyeicosatetraenoic acid metabolism by mouse peritoneal macrophagesS N Mathur0F J Field1Department of Internal Medicine, University of Iowa, Iowa City 52242.Department of Internal Medicine, University of Iowa, Iowa City 52242.The metabolism of 12-hydroxyeicosatetraenoic acid (12-HETE) was investigated in mouse peritoneal macrophages enriched in cholesterol by incubation with acetylated low density lipoproteins. After incubating with labeled arachidonic acid, cholesterol-rich cells released more 12-HETE into the medium than unmodified macrophages. With time, however, 12-HETE decreased in the medium of both cell preparations suggesting re-uptake of this monohydroxyfatty acid and perhaps further metabolism. When control macrophages were incubated with radiolabeled 12-HETE for 2 hr, almost 70% of the cell-associated 12-HETE label was incorporated into phospholipids. In contrast, in cholesterol-rich cells, only 31% of the 12-HETE label was incorporated into phospholipids. Bee venom phospholipase completely hydrolyzed the label, suggesting that the monohydroxyfatty acid was esterified at the sn-2 position of the phospholipid. In cholesterol-rich cells, 69% of the 12-HETE was diverted into neutral lipids. Two major neutral lipids were identified in cholesterol-rich macrophages. One neutral lipid band which migrated with an Rf value of 0.34 contained the hydroxylated fatty acid esterified to a glyceride. The other neutral lipid band having an Rf value of 0.49 contained cholesterol and by further analysis was found to contain predominantly cholesteryl-12-HETE. The labeled fatty acids in these two neutral lipids were mostly oxidized products of 12-HETE in contrast to the native 12-HETE observed in the phospholipids. Cholesterol-rich macrophages released 25% more products of 12-HETE metabolism than control macrophages. Two major products were observed in the medium which eluted in the area of a standard di-HETE, LTB4, on high performance liquid chromatography (HPLC) analysis. We propose that the reincorporation of 12-HETE into these neutral lipids and the increased capacity for further metabolism of this biologically potent hydroxyfatty acid could be a mechanism by which the cholesterol-rich macrophage maintains its membrane function, and regulates the amount of 12-HETE in the pericellular space.http://www.sciencedirect.com/science/article/pii/S0022227520386016
collection DOAJ
language English
format Article
sources DOAJ
author S N Mathur
F J Field
spellingShingle S N Mathur
F J Field
Effect of cholesterol enrichment on 12-hydroxyeicosatetraenoic acid metabolism by mouse peritoneal macrophages
Journal of Lipid Research
author_facet S N Mathur
F J Field
author_sort S N Mathur
title Effect of cholesterol enrichment on 12-hydroxyeicosatetraenoic acid metabolism by mouse peritoneal macrophages
title_short Effect of cholesterol enrichment on 12-hydroxyeicosatetraenoic acid metabolism by mouse peritoneal macrophages
title_full Effect of cholesterol enrichment on 12-hydroxyeicosatetraenoic acid metabolism by mouse peritoneal macrophages
title_fullStr Effect of cholesterol enrichment on 12-hydroxyeicosatetraenoic acid metabolism by mouse peritoneal macrophages
title_full_unstemmed Effect of cholesterol enrichment on 12-hydroxyeicosatetraenoic acid metabolism by mouse peritoneal macrophages
title_sort effect of cholesterol enrichment on 12-hydroxyeicosatetraenoic acid metabolism by mouse peritoneal macrophages
publisher Elsevier
series Journal of Lipid Research
issn 0022-2275
publishDate 1987-10-01
description The metabolism of 12-hydroxyeicosatetraenoic acid (12-HETE) was investigated in mouse peritoneal macrophages enriched in cholesterol by incubation with acetylated low density lipoproteins. After incubating with labeled arachidonic acid, cholesterol-rich cells released more 12-HETE into the medium than unmodified macrophages. With time, however, 12-HETE decreased in the medium of both cell preparations suggesting re-uptake of this monohydroxyfatty acid and perhaps further metabolism. When control macrophages were incubated with radiolabeled 12-HETE for 2 hr, almost 70% of the cell-associated 12-HETE label was incorporated into phospholipids. In contrast, in cholesterol-rich cells, only 31% of the 12-HETE label was incorporated into phospholipids. Bee venom phospholipase completely hydrolyzed the label, suggesting that the monohydroxyfatty acid was esterified at the sn-2 position of the phospholipid. In cholesterol-rich cells, 69% of the 12-HETE was diverted into neutral lipids. Two major neutral lipids were identified in cholesterol-rich macrophages. One neutral lipid band which migrated with an Rf value of 0.34 contained the hydroxylated fatty acid esterified to a glyceride. The other neutral lipid band having an Rf value of 0.49 contained cholesterol and by further analysis was found to contain predominantly cholesteryl-12-HETE. The labeled fatty acids in these two neutral lipids were mostly oxidized products of 12-HETE in contrast to the native 12-HETE observed in the phospholipids. Cholesterol-rich macrophages released 25% more products of 12-HETE metabolism than control macrophages. Two major products were observed in the medium which eluted in the area of a standard di-HETE, LTB4, on high performance liquid chromatography (HPLC) analysis. We propose that the reincorporation of 12-HETE into these neutral lipids and the increased capacity for further metabolism of this biologically potent hydroxyfatty acid could be a mechanism by which the cholesterol-rich macrophage maintains its membrane function, and regulates the amount of 12-HETE in the pericellular space.
url http://www.sciencedirect.com/science/article/pii/S0022227520386016
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