Cultured bovine coronary arterial endothelial cells synthesize HETEs and prostacyclin

1988 ◽  
Vol 254 (1) ◽  
pp. C8-C19 ◽  
Author(s):  
G. E. Revtyak ◽  
A. R. Johnson ◽  
W. B. Campbell
Keyword(s):  
Endothelial Cells ◽  
Arachidonic Acid ◽  
Cell Monolayer ◽  
Arachidonic Acid Metabolism ◽  
Biologically Active ◽  
Vasoactive Agent ◽  
Exogenous Arachidonic Acid ◽  
Coronary Endothelial Cells ◽  
Qualitative Pattern ◽  
Von Willebrand’S Factor

Arachidonic acid metabolism was examined in endothelial cells cultured from bovine coronary arteries. In culture, these cells exhibit specific characteristics of endothelial cells. They form a contact-inhibited monolayer with a cobblestone appearance, contain immunoreactive von Willebrand's factor antigen, and have angiotensin I converting enzyme activity. Prostacyclin was the major prostaglandin synthesized from exogenous and endogenous arachidonic acid in these cells. In addition, exogenous arachidonic acid was metabolized to small amounts of prostaglandin E2 (PGE2) and several relatively nonpolar metabolites including 12-, 15-, and 11-hydroxyeicosatetraenoic acids (12-, 15-, and 11-HETE). Histamine, bradykinin, and thrombin increased PGI2 synthesis in these bovine coronary endothelial cells. Of these agonists, bradykinin was the most potent, increasing basal PGI2 release by fourfold. More vigorous stimulation of the cells with mechanical disruption of the cell monolayer, melittin, or A23187 resulted in release of both PGI2 and PGE2. Pretreatment of cells with exogenous arachidonic acid (10(-5) M) abolished their responsiveness to subsequent stimulation by arachidonic acid or vasoactive agents, but not PGH2. Furthermore, treatment of cells with 15-HPETE (10(-7)-10(-4) M), but not 15-HETE, specifically inhibited basal as well as A23187-stimulated PGI2 release. PGE2 release was increased slightly after 15-HPETE treatment. These studies indicate that bovine coronary endothelial cells can metabolize arachidonic acid to several biologically active products and that PGI2 synthesis by these cells is specifically related to the type of vasoactive agent employed. Both the qualitative pattern and quantity of eicosanoids synthesized by bovine coronary endothelial cells differ substantially from endothelial cells isolated from noncardiac vascular beds.

Cytochrome P450 Isoform Expression in Human Vascular Endothelial Cells

Hypertension ◽  
2000 ◽  
Vol 36 (suppl_1) ◽  
pp. 698-698
Author(s):  
Eduardo Barbosa-Sicard ◽  
Eva Kaergel ◽  
Dominik N Muller ◽  
Horst Honeck ◽  
Friedrich C Luft ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Arachidonic Acid ◽  
Cytochrome P450 ◽  
Vascular Endothelial Cells ◽  
Arachidonic Acid Metabolism ◽  
Vascular Endothelial ◽  
Rt Pcr ◽  
Pcr Screening ◽  
Mediators Of Inflammation ◽  
Derivatives Of

P29 Epoxy derivatives of arachidonic acid may act as important autocrine and paracrine mediators of endothelial function including regulation of vascular tone and control of inflammation. To identify potential candidates for catalyzing the synthesis of these and further arachidonic acid metabolites, we studied human vascular endothelial cells for the expression of individual cytochrome P450 isoforms belonging to the CYP families 1, 2, 3 and 4. An RT-PCR screening performed with subfamily- and isoform-specific primer pairs revealed mRNAs for the P450 forms 1A1, 1B1, 2C8, 2E1, 2J2, 3A7, 4A11 and 4F2. The identity of the RT-PCR products was confirmed by DNA sequencing. In addition, P450 1A2 mRNA was detected after induction with β-naphthoflavone which also enhanced the expresion of P450s 1A1 and 1B1. P450s 2B6 and 3A4 were not detectable. Similar P450 isoform patterns were obtained analyzing primary human endothelial cells originating from aorta, coronary arteries, dermal microvessels and umbilical veins, as well as an immortalized human endothelial cell line (HMEC-1). Further studies with HMEC-1 cells showed the expression of all human members of the P450 2C subfamily (2C8, 2C9, 2C18 and 2C19). We next used gaschromatography-mass spectrometry to identify the regioisomeric epoxeicosatrienoic acids produced by HMEC-1 cells. Among the P450 forms detected by the RT-PCR screening, P450 2C8 and 2J2 are the leading candidates for producing vasoactive epoxyeicosatrienoic acids. Using recombinant human P450 1A1, we then found that this P450 form catalyzes the formation of various regioisomeric hydroxy derivatives of arachidonic acid. We conclude that P450 1A1 known primarily for its role in polycyclic aromatic hydrocarbon metabolism, may interfere with endothelial arachidonic acid metabolism, particularly after its induction by drugs and xenobiotics. Furthermore, P450s 4A11 and 4F2 probably contribute to the degradation of lipid mediators of inflammation.

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 A New Pathway for Arachidonic Acid Metabolism in Human Platelets

1977 ◽  
Author(s):  
S. Rittenhouse-Simmons ◽  
F. A. Russell ◽  
D. Deykin
Keyword(s):  
Arachidonic Acid ◽  
Acid Metabolism ◽  
De Novo ◽  
Platelet Rich Plasma ◽  
Gel Filtration ◽  
Kinetic Studies ◽  
Arachidonic Acid Metabolism ◽  
Biologically Active ◽  
Resting Cells ◽  
Active Metabolites

We are reporting a novel pathway of arachidonic acid metabolism in the phosphatides of thrombin-activated platelets. For kinetic studies of arachidonic acid turnover, platelet phosphatides were labeled by incubation of platelet rich plasma with (3H)-arachidonic acid for 15 min. Unincorporated isotope was removed during subsequent gel-filtration. Platelet phosphatides were resolved and quantitated following two-dimensional silica paper chromatography of chloroform/methanol extracts of incubated platelets. Plasmalogen phosphatidylethanolamine (PPE) was examined on paper chromatograms after its breakdown to lysoPPE with HgCl2. In other experiments, gel-filtered platelets were incubated with (14C)-glycerol to monitor de novo phosphatide synthesis. (3H)-Arachidonic acid was released from phosphatidylcholine and phosphatidylinositol of pre-labeled platelets exposed to thrombin and appeared increasingly in PPE in acyl linkage at glycerol-C-2. (3H)-Arachidonic acid was not found in PPE of resting cells. Maximum transfer occurred with 5 U/ml of thrombin and 15 min, of incubation, with t½ of 2½ min., and was Ca+2 dependent. The presence of aspirin, indomethacin, or eicosatetraynoic acid did not prevent the thrombin-activated transfer of (3H)-arachidonic acid to PPE. The stimulated incorporation of (3H)-arachidonic acid into PPE was not accompanied by a stimulation of (14C)-glycerol uptake into this phosphatide. We suggest that perturbation of the platelet may activate a phospholipase A2 leading to turnover of arachidonic acid in PPE, which is rich in this fatty acid. Such turnover may provide substrate for conversion by cyclo-oxygenase and lipoxydase to biologically active metabolites, and therefore, may offer a locus for regulation of prostaglandin synthesis in the human platelet.

ARACHIDONIC ACID METABOLISM IN ENDOTHELIAL CELLS AND PLATELETS

1982 ◽  
Vol 401 (1 Endothelium) ◽  
pp. 195-202 ◽  
Author(s):  
A. J. Marcus ◽  
M. J. Broekman ◽  
B. B. Weksler ◽  
E. A. Jaffe ◽  
L. B. Safier ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Arachidonic Acid ◽  
Acid Metabolism ◽  
Arachidonic Acid Metabolism

Arachidonic acid metabolism in cultured aortic endothelial cells

1985 ◽  
Vol 34 (1) ◽  
pp. 119-123 ◽  
Author(s):  
A.Richard Whorton ◽  
James B. Collawn ◽  
Malcolm E. Montgomery ◽  
Stephen L. Young ◽  
Richard S. Kent
Keyword(s):  
Endothelial Cells ◽  
Arachidonic Acid ◽  
Acid Metabolism ◽  
Arachidonic Acid Metabolism ◽  
Aortic Endothelial Cells ◽  
Aortic Endothelial

Kinetic profile of the rat CYP4A isoforms: arachidonic acid metabolism and isoform-specific inhibitors

1999 ◽  
Vol 276 (6) ◽  
pp. R1691-R1700 ◽  
Author(s):  
Xuandai Nguyen ◽  
Mong-Heng Wang ◽  
Komandla M. Reddy ◽  
John R. Falck ◽  
Michal Laniado Schwartzman
Keyword(s):  
Arachidonic Acid ◽  
Biological Effects ◽  
Catalytic Efficiency ◽  
Arachidonic Acid Metabolism ◽  
Biologically Active ◽  
Epoxyeicosatrienoic Acid ◽  
Active Metabolites ◽  
Extrahepatic Tissues ◽  
Renal Tubular ◽  
Biologically Active Metabolites

20-Hydroxyeicosatetraenoic acid (HETE), the cytochrome P-450 (CYP) 4A ω-hydroxylation product of arachidonic acid, has potent biological effects on renal tubular and vascular functions and on the control of arterial pressure. We have expressed high levels of the rat CYP4A1, -4A2, -4A3, and -4A8 cDNAs, using baculovirus and Sf 9 insect cells. Arachidonic acid ω- and ω-1-hydroxylations were catalyzed by three of the CYP4A isoforms; the highest catalytic efficiency of 947 nM−1 ⋅ min−1for CYP4A1 was followed by 72 and 22 nM−1 ⋅ min−1for CYP4A2 and CYP4A3, respectively. CYP4A2 and CYP4A3 exhibited an additional arachidonate 11,12-epoxidation activity, whereas CYP4A1 operated solely as an ω-hydroxylase. CYP4A8 did not catalyze arachidonic or linoleic acid but did have a detectable lauric acid ω-hydroxylation activity. The inhibitory activity of various acetylenic and olefinic fatty acid analogs revealed differences and indicated isoform-specific inhibition. These studies suggest that CYP4A1, despite its low expression in extrahepatic tissues, may constitute the major source of 20-HETE synthesis. Moreover, the ability of CYP4A2 and -4A3 to catalyze the formation of two opposing biologically active metabolites, 20-HETE and 11,12-epoxyeicosatrienoic acid, may be of great significance to the regulation of vascular tone.

Biochemistry of the lipoxygenase pathways in neutrophils

1989 ◽  
Vol 67 (8) ◽  
pp. 936-942 ◽  
Author(s):  
Pierre Borgeat
Keyword(s):  
Arachidonic Acid ◽  
Ring Opening ◽  
Arachidonic Acid Metabolism ◽  
Biologically Active ◽  
Eicosatetraenoic Acid ◽  
Major Pathway ◽  
Inflammatory Reactions ◽  
Conjugated Triene ◽  
Hydroxyeicosatetraenoic Acids ◽  
Active Substances

Three mammalian lipoxygenases have been reported to date. They catalyze the insertion of oxygen at positions 5, 12, and 15 of various 20-carbon polyunsaturated fatty acids. In the case of arachidonic acid, the immediate products are hydroperoxyeicosatetraenoic acids (HPETEs). HPETEs can undergo different transformations. One reaction is a reduction of the hydroperoxy group yielding the corresponding hydroxyeicosatetraenoic acids (HETEs). In the neutrophils, the major pathway of arachidonic acid metabolism is the 5-lipoxygenase. In these cells the 5-HPETE undergoes a cyclization reaction leading to a 5(6)-epoxy(oxido)eicosatetraenoic acid or leukotriene A4. The 5(6)-epoxy fatty acid can undergo three additional transformations: (a) a nonenzymatic hydrolysis to epimeric dihydroxyeicosatetraenoic acids (diHETEs); (b) stereospecific enzymatic hydrolysis to a specific diHETE, leukotriene B4; or (c) ring opening by reduced glutathione (GSH) to yield a peptidolipid, named leukotriene C4, in which GSH is attached via a sulfoether linkage. The leukotrienes constitute a group of biologically active substances probably involved in allergic and inflammatory reactions. The 5(6)-epoxy-eicosatetraenoic acid and the products derived from it contain a conjugated triene unit; the term leukotriene also denotes the cells (leukocytes) recognized to form these products, mainly the neutrophils, eosinophils, basophils, monocytes, mast cells, and macrophages. In the present article various aspects of the biochemistry of the lipoxygenase pathways of neutrophils are reviewed.Key words: arachidonic acid, leukotrienes, leukocytes, lipoxygenase, inflammation.

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