Diacylglycerols derived from membrane phospholipids are metabolized by lipases in A10 smooth muscle cells

1996 ◽  
Vol 271 (4) ◽  
pp. C1194-C1202 ◽  
Author(s):  
I. Migas ◽  
D. L. Severson
Keyword(s):  
Arachidonic Acid ◽  
Smooth Muscle ◽  
Fatty Acid ◽  
Phosphatidic Acid ◽  
Smooth Muscle Cells ◽  
Fold Increase ◽  
Muscle Cells ◽  
Membrane Phospholipids ◽  
Metabolic Fate ◽  
Triacylglycerol Synthesis

The metabolic fate of endogenous diacylglycerol (DAG) in cultured A10 smooth muscle cells was determined. Preincubation of A10 cells with [3H]myristic acid or [3H]arachidonic acid resulted in preferential labeling of phosphatidylcholine (PC) or phosphatidylinositol (PI), respectively. Addition of PC-specific phospholipase C (PC-PLC) to [3H]myristate-labeled A10 cells resulted in a 10-fold increase in radiolabeled DAG, which was converted to monoacylglycerol (MG) and fatty acid (FA). DAG degradation and MG formation was inhibited by tetrahydrolipstatin, a DAG lipase inhibitor. PC-derived DAG was not converted to phosphatidic acid; in addition, PC resynthesis or triacylglycerol synthesis was not observed. Addition of PI-specific PLC (PI-PLC) to [3H]arachidonate-labeled A10 cells resulted in a modest increase in radiolabeled DAG that was also hydrolyzed to MG and FA. Therefore, the principal metabolic fate of endogenous DAG generated from membrane phospholipids by treatment of A10 cells with PC-PLC and PI-PLC was hydrolysis by a DAG lipase pathway.

scholarly journals Incorporation of platelet and leukocyte lipoxygenase metabolites by cultured vascular cells

Blood ◽  
1986 ◽  
Vol 67 (2) ◽  
pp. 373-378 ◽  
Author(s):  
AI Schafer ◽  
H Takayama ◽  
S Farrell ◽  
MA Jr Gimbrone
Keyword(s):  
Endothelial Cells ◽  
Arachidonic Acid ◽  
Smooth Muscle ◽  
Fatty Acid ◽  
Smooth Muscle Cells ◽  
Vascular Function ◽  
Muscle Cells ◽  
Arachidonic Acid Metabolism ◽  
Eicosatetraenoic Acid

Abstract When arachidonic acid metabolism is studied during platelet-endothelial interactions in vitro, the predominant cyclooxygenase end products of each cell type (thromboxane B2 and 6-keto-prostaglandin-F1 alpha, respectively) are essentially completely recovered in the cell-free supernatants of these reactions. In contrast, 50% of 12-hydroxy- 5,8,10,14-eicosatetraenoic acid (12-HETE), the major lipoxygenase metabolite from platelets, is released into the cell-free supernatant. In investigating the basis of this observation, we have found that platelet lipoxygenase metabolites were generated to the same extent during these coincubations but became rapidly incorporated into the endothelial cells. The endothelial cell-associated 12-HETE was present not only as free fatty acid, but was also incorporated into cellular phospholipids and triglycerides. When purified 3H-12-HETE, 3H-5-HETE (the major hydroxy acid lipoxygenase product of leukocytes), and 3H- arachidonic acid (the common precursor of these metabolites) were individually incubated with suspensions of cultured bovine aortic endothelial cells or smooth muscle cells, different patterns of intracellular lipid distribution were found. In endothelial cells, 12- HETE was incorporated equally into phospholipids and triglycerides, whereas 5-HETE was incorporated preferentially into triglycerides, and arachidonic acid was incorporated into phospholipids. In smooth muscle cells, both 12-HETE and 5-HETE showed more extensive incorporation into triglycerides. The rapid and characteristic incorporation and esterification of platelet and leukocyte monohydroxy fatty acid lipoxygenase products by endothelial and smooth muscle cells suggests a possible physiologic role for these processes in regulating vascular function.

scholarly journals Incorporation of platelet and leukocyte lipoxygenase metabolites by cultured vascular cells

Blood ◽  
1986 ◽  
Vol 67 (2) ◽  
pp. 373-378
Author(s):  
AI Schafer ◽  
H Takayama ◽  
S Farrell ◽  
MA Jr Gimbrone
Keyword(s):  
Endothelial Cells ◽  
Arachidonic Acid ◽  
Smooth Muscle ◽  
Fatty Acid ◽  
Smooth Muscle Cells ◽  
Vascular Function ◽  
Muscle Cells ◽  
Arachidonic Acid Metabolism ◽  
Eicosatetraenoic Acid

When arachidonic acid metabolism is studied during platelet-endothelial interactions in vitro, the predominant cyclooxygenase end products of each cell type (thromboxane B2 and 6-keto-prostaglandin-F1 alpha, respectively) are essentially completely recovered in the cell-free supernatants of these reactions. In contrast, 50% of 12-hydroxy- 5,8,10,14-eicosatetraenoic acid (12-HETE), the major lipoxygenase metabolite from platelets, is released into the cell-free supernatant. In investigating the basis of this observation, we have found that platelet lipoxygenase metabolites were generated to the same extent during these coincubations but became rapidly incorporated into the endothelial cells. The endothelial cell-associated 12-HETE was present not only as free fatty acid, but was also incorporated into cellular phospholipids and triglycerides. When purified 3H-12-HETE, 3H-5-HETE (the major hydroxy acid lipoxygenase product of leukocytes), and 3H- arachidonic acid (the common precursor of these metabolites) were individually incubated with suspensions of cultured bovine aortic endothelial cells or smooth muscle cells, different patterns of intracellular lipid distribution were found. In endothelial cells, 12- HETE was incorporated equally into phospholipids and triglycerides, whereas 5-HETE was incorporated preferentially into triglycerides, and arachidonic acid was incorporated into phospholipids. In smooth muscle cells, both 12-HETE and 5-HETE showed more extensive incorporation into triglycerides. The rapid and characteristic incorporation and esterification of platelet and leukocyte monohydroxy fatty acid lipoxygenase products by endothelial and smooth muscle cells suggests a possible physiologic role for these processes in regulating vascular function.

Oxidant-induced arachidonic acid release and impairment of fatty acid acylation in vascular smooth muscle cells

1998 ◽  
Vol 274 (4) ◽  
pp. C1040-C1046 ◽  
Author(s):  
Agnès Cane ◽  
Michelyne Breton ◽  
Kamen Koumanov ◽  
Gilbert Béréziat ◽  
Odile Colard
Keyword(s):  
Oxidative Stress ◽  
Arachidonic Acid ◽  
Smooth Muscle ◽  
Oleic Acid ◽  
Fatty Acid ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Atp Content

Oxidative damage, which plays a major role in the early stages of atherosclerosis, is associated with arachidonic acid (AA) release in vascular smooth muscle cells (VSMC) as in other cell types. In this study, H2O2was used to investigate mechanisms of AA release from VSMC on oxidative stress. Cell treatment with H2O2inhibited AA incorporation in an inverse relationship to prolonged H2O2-induced AA release. Identical kinetics of inhibition of AA incorporation and AA release were observed after cell treatment with A[Formula: see text], a process not involving phospholipase A2(PLA2) activation as recently described (A. Cane, M. Breton, G. Béréziat, and O. Colard. Biochem. Pharmacol. 53: 327–337, 1997). AA release was not specific, since oleic acid also increased in the extracellular medium of cells treated with H2O2or A[Formula: see text] as measured by gas chromatography-mass spectrometry. In contrast, AA and oleic acid cell content decreased after cell treatment. Oleoyl and arachidonoyl acyl-CoA synthases and acyltransferases, assayed using a cell-free system, were not significantly modified. In contrast, a good correlation was observed between decreases in AA acylation and cell ATP content. The decrease in ATP content is only partially accounted for by mitochondrial damage as assayed by rhodamine 123 assay. We conclude that oxidant-induced arachidonate release results from impairment of fatty acid esterification and that ATP availability is probably responsible for free AA accumulation on oxidative stress by preventing its reesterification and/or transmembrane transport.

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.

Abstract 361: Cyclophilin A Mediates Angiotensin II--Stimulated NADPH Oxidase Activation in Vascular Smooth Muscle Cells

2012 ◽  
Vol 32 (suppl_1) ◽  
Author(s):  
Nwe Nwe Soe ◽  
Mark Sowden ◽  
Patrizia Nigro ◽  
Bradford C Berk
Keyword(s):  
Smooth Muscle ◽  
Plasma Membrane ◽  
Nadph Oxidase ◽  
Smooth Muscle Cells ◽  
Fold Increase ◽  
Muscle Cells ◽  
Dependent Manner ◽  
Ang Ii ◽  
Membrane Translocation ◽  
Ppiase Activity

Objective: Cyclophilin A (CyPA) is a ubiquitously expressed cytosolic protein that possesses PPIase activity and scaffold function. CyPA regulates Angiotensin II (Ang II) induced reactive oxygen species (ROS) production in vascular smooth muscle cells. However, the mechanism of this CyPA regulation remains unclear. We hypothesized that CyPA regulates plasma membrane translocation of NADPH oxidase cytosolic subunit, p47phox, which is required for NADPH oxidase structural organization and activity. Methods and results: Immunofluorescence studies in rat aortic smooth muscle cells revealed that CyPA translocated from the cytosol to the plasma membrane in response to Ang II in a time dependent manner with a peak at 10min (46.4±5.4 fold increase). Mouse Aortic Smooth Muscle Cells (MASM) were isolated from mice lacking CyPA (CyPA-/-) and wild type controls (WT), treated with Ang II (100nM) and immunofluorescence analysis was performed. Ang II induced p47phox plasma membrane translocation at 10min in WT mice. However, p47 phox translocation was significantly inhibited in CyPA -/- MASM. CyPA and p47phox colocalized at the plasma membrane in response to Ang II. Further analysis using subcellular fractionation studies confirmed that Ang II induced p47phox plasma membrane translocation was inhibited in CyPA -/- MASM compared to WT (1.2±2.7 vs 4.3±3.4 fold increase). Coimmunoprecipitation analyses confirmed that Ang II increased CyPA association with p47phox in a time dependent manner (2.5±3.4 fold increase at 10min). Finally, pretreatment with the PPIase activity inhibitor, cyclosporine A (1uM), could not inhibit CyPA association with p47phox and CyPA mediated p47phox translocation to the plasma membrane. Conclusion: These data suggest that Ang II promotes an association between CyPA and p47phox that enhances plasma membrane translocation of p47phox. This is proposed to increase the NADPH oxidase activity thereby increasing cellular ROS production. This process is independent of the PPIase activity of CyPA. Therefore, inhibition of the CyPA and p47phox association could be a future therapeutic target for Ang II induced ROS regulated cardiovascular diseases such as atherosclerosis and abdominal aortic aneurysm formation.

Conjugated Linoleic Acids Exert Similar Actions on Prostanoid Release from Aortic and Coronary Artery Smooth Muscle Cells

2006 ◽  
Vol 76 (5) ◽  
pp. 281-289 ◽  
Author(s):  
Ringseis ◽  
Gahler ◽  
Herter ◽  
Eder
Keyword(s):  
Smooth Muscle ◽  
Fatty Acid ◽  
Coronary Artery ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
Biologically Active ◽  
Similar Degree ◽  
Conjugated Linoleic Acids ◽  
Vascular Smcs ◽  
Cla Isomers

Conjugated linoleic acids (CLAs) are biologically active lipid compounds exerting anti-atherogenic actions in vivo without exact knowledge about the underlying mechanisms. Recently, CLAs were shown to lower the release of vasoactive prostanoids from vascular smooth muscle cells (SMCs) which play a central role in atherosclerosis. Since SMCs from different vascular locations were shown to exert differential actions in response to a common stimulus, the present study aimed to explore potential differential effects of CLA isomers on the release of the prostanoids PGE2 and PGI2 from coronary artery and aortic SMCs. For this purpose, human aortic and coronary artery SMCs were incubated with 5 and 50 μmol/L of cis-9, trans-11 CLA and trans-10, cis-12 CLA for 24 hours and analyzed for fatty acid composition and the release of prostaglandins E2 and I2 (PGE2 and PGI2). Incubations were performed in the absence (basal conditions) and in the presence of 10 ng/mL of the cytokine tumor necrosis factor-α (TNFα) (cytokine-stimulated conditions). Fatty acid analysis revealed a similar degree of incorporation of CLA isomers and dose-dependent reduction of arachidonic acid in total cell lipids of both types of vascular SMCs following treatment with CLA. The release of PGE2 and PGI2 was dose-dependently inhibited by either CLA isomer from both types of vascular SMCs. The inhibitory potential of CLA isomers on the release of prostanoids was slightly different between basal and cytokine-stimulated conditions. In conclusion, the present findings suggest that the action of CLA isomers on the release of vasoactive prostanoids from vascular SMCs is largely independent of the vascular location; e.g., coronary arteries or systemic vasculature (aorta), but partially depends on the pathophysiological status of SMCs. The observed anti-inflammatory effect of CLAs may contribute to the anti-atherogenic actions of CLA.

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