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The Journal of Experimental Medicine Dec 1993Studies were undertaken to assess the biochemical effects of dietary supplementation with n-9 eicosatrienoic acid (ETrA), an arachidonic acid analogue that is normally...
Studies were undertaken to assess the biochemical effects of dietary supplementation with n-9 eicosatrienoic acid (ETrA), an arachidonic acid analogue that is normally present in cell membranes at very low levels but is raised in the presence of essential fatty acid deficiency (EFAD). The incorporation of dietary ETrA into rat neutrophils and its effect on A23187-stimulated 5-lipoxygenase metabolism in these cells was examined; in addition, the effect of ETrA was compared with that of another arachidonic acid analogue, eicosapentaenoic acid (EPA), which is known to accumulate in cell membranes and inhibit synthesis of leukotriene B4 (LTB4) a product of the 5-lipoxygenase metabolic pathway. Rats were fed a defined diet that was sufficient in essential fatty acids and that contained EPA or ETrA (0.014% of energy) or no added fatty acid, for 3 wk. In the cells from ETrA-fed rats, LTB4 synthesis was inhibited relative to control values, but synthesis of the other products of 5-lipoxygenase metabolism, 5-hydroxyeicosatetraenoic acid (5-HETE) and the all-trans isomers of LTB4, were not inhibited. This pattern indicates inhibition of LTA hydrolase in ETrA-fed rats. In EPA-fed rats, there was inhibition of LTB4 and the all-trans isomers of LTB4, but there was no inhibition of 5-HETE. This pattern indicates inhibition of LTA synthase in EPA-fed rats. The results establish that dietary ETrA effectively inhibits synthesis of the inflammatory mediator, LTB4, and suggest that ETrA may confer antiinflammatory benefits similar to those observed with EFAD or dietary fish oil (which contains EPA). Because ETrA is substantially less unsaturated than EPA, it can be expected to have greater chemical stability, which could be an important practical advantage when used as a dietary constituent or supplement.
Topics: 8,11,14-Eicosatrienoic Acid; Animals; Dietary Fats; Eicosanoids; Eicosapentaenoic Acid; Leukotriene B4; Male; Neutrophils; Rats; Rats, Wistar
PubMed: 8245797
DOI: 10.1084/jem.178.6.2261 -
The Journal of Biological Chemistry Nov 1983Analysis of products derived from 5,8,11-eicosatrienoic acid via the 5-lipoxygenase-leukotriene pathway showed that this fatty acid is readily converted to leukotriene...
Analysis of products derived from 5,8,11-eicosatrienoic acid via the 5-lipoxygenase-leukotriene pathway showed that this fatty acid is readily converted to leukotriene (LT)A3. When 10,000 X g supernatant from rat basophilic leukemia cell homogenates was incubated with 30 microM fatty acid, 5,8,11-eicosatrienoic acid produced 6.2 +/- 1.1 nmol of LTA3 and arachidonic acid 15.5 +/- 1.9 nmol of LTA4 (n = 4). However, only insignificant amounts of LTB3 were formed (0.15 +/- 0.04 nmol of LTB3 and 4.2 +/- 0.4 nmol of LTB4, n = 4). These data indicate that the LTA-hydrolase requires not only the three double bonds of the triene but also the double bond at C-14 to efficiently convert LTA to LTB. These findings have significant implications for essential fatty acid deficiency.
Topics: 8,11,14-Eicosatrienoic Acid; Animals; Arachidonate Lipoxygenases; Arachidonic Acids; Basophils; Cell Line; Chromatography, High Pressure Liquid; Fatty Acids, Unsaturated; Isomerism; Leukemia, Experimental; Leukotriene A4; Lipoxygenase; Mass Spectrometry; Rats
PubMed: 6313677
DOI: No ID Found -
Applied and Environmental Microbiology Sep 2005An oleaginous fungus, Mortierella alpina 1S-4, is used commercially for arachidonic acid production. Delta12-Desaturase, which desaturates oleic acid (18:1n-9) to...
Improvement of the fatty acid composition of an oil-producing filamentous fungus, Mortierella alpina 1S-4, through RNA interference with delta12-desaturase gene expression.
An oleaginous fungus, Mortierella alpina 1S-4, is used commercially for arachidonic acid production. Delta12-Desaturase, which desaturates oleic acid (18:1n-9) to linoleic acid (18:2n-6), is a key enzyme in the arachidonic acid biosynthetic pathway. To determine if RNA interference (RNAi) by double-stranded RNA occurs in M. alpina 1S-4, we silenced the Delta12-desaturase gene. The silenced strains accumulate 18:2n-9, 20:2n-9, and Mead acid (20:3n-9), which are not detected in either the control strain or wild type strain 1S-4. The fatty acid composition of stable transformants was similar to that of Delta12-desaturation-defective mutants previously identified. Thus, RNAi occurs in M. alpina and could be used to alter the types and relative amounts of fatty acids produced by commercial strains of this fungus without mutagenesis or other permanent changes in the genetic background of the producing strains.
Topics: Arachidonic Acid; Culture Media; Fatty Acid Desaturases; Fatty Acids, Unsaturated; Gene Silencing; Industrial Microbiology; Mortierella; RNA Interference; RNA, Fungal; Transformation, Genetic
PubMed: 16151095
DOI: 10.1128/AEM.71.9.5124-5128.2005 -
The Journal of Investigative Dermatology May 1981The present studies have demonstrated that topical application of a low concentration of eicosa-5,8,11-trienoic acid (a 20:3,n9 fatty acid previously reported to inhibit...
The present studies have demonstrated that topical application of a low concentration of eicosa-5,8,11-trienoic acid (a 20:3,n9 fatty acid previously reported to inhibit competitively the activity of the sheep vesicular cyclooxygenase) to skin of normal fed hairless mice produced severe scaly dermatosis which is characterized by marked hyperplasia and acanthosis of the epidermal layer. The precise mechanism of this induction of scaly dermatosis is presently unclear. It is nonetheless interesting that the treatment of skin with similar concentrations of other unsaturated fatty acids produced no visible or histologic effects. Furthermore, endogenous levels of arachidonic acid in epidermal phospholipid and triglyceride fractions were shown to increase significantly (p < 0.01) in skin treated with the 20:3,n9 fatty acid while the endogenous level of PGE2 in the same tissue decreased markedly. This latter observation is consistent at least in part, with a previous report from this laboratory in which the 20:3,n9 fatty acid inhibited in vitro the activity of the sheep vesicular cyclooxygenase (the rate limiting enzyme in the transformation of arachidonic acid into the prostaglandin endoperoxides) although the increase in arachidonic acid may also reflect an increased incorporation of this fatty acid into the epidermal lipids by the hyperproliferative tissue. Evaluation of the proliferative status of 20:3,n9 fatty acid-treated skin showed a significant increase (p < 0.01) in labeling and mitotic indices. The use of this potentially endogenous fatty acid may be a useful tool for further investigations of hyperproliferative skin diseases where dietary deficiency of essential fatty acids does not exist.
Topics: 8,11,14-Eicosatrienoic Acid; Animals; Arachidonic Acids; Cell Division; Disease Models, Animal; Fatty Acids, Unsaturated; Female; Lipids; Mice; Mice, Nude; Prostaglandins E; Skin; Skin Diseases
PubMed: 7229430
DOI: 10.1111/1523-1747.ep12520900 -
The Journal of Clinical Investigation Jul 1983We have examined the relative rates of uptake of several fatty acids into washed, human platelets by measuring incorporation into cellular phospholipids. In the presence...
We have examined the relative rates of uptake of several fatty acids into washed, human platelets by measuring incorporation into cellular phospholipids. In the presence of 15 microM fatty acid-free albumin and with radioactive fatty acid concentrations of 5-500 nM, esterification into phospholipid was linear with time and platelet concentration and saturable with respect to fatty acid concentration. Two distinct classes of uptake rate were observed. Arachidonate and 5,8,11,14,17-eicosapentaenoate exhibited high affinity, relatively rapid incorporation into platelet phospholipids at pH 6.5: apparent Michaelis constant (Km) = 30 nM, apparent maximum velocity (Vmax) = 28 pmol/min per 10(9) platelets. Two other eicosanoid precursors, 5,8,11-eicosatrienoate and 8,11,14-eicosatrienoate, exhibited the same Vmax, but Km of 85 and 60 nM, respectively. Under the same conditions, stearate, oleate, and linoleate were incorporated into phospholipids much less efficiently (Vmax approximately 8 pmol/10(9) cells per min, apparent Km greater than or equal to 170 nM). Qualitatively similar results were found at pH 7.4. Uptake of radiolabeled, rapid-uptake fatty acids was not diminished by the presence of excess, unlabeled, slow-uptake fatty acids. Thus, the specificity of this esterification system resembles that of the arachidonate-specific, long-chain acyl-CoA synthetase present in platelets. It may represent the expression in vivo of the synthetase, although the apparent affinity of the synthetase for fatty acid is much less. This esterification system probably represents the physiologic mechanism for platelet arachidonate uptake, whereby arachidonate is collected from plasma, despite the fact that its concentration is considerably lower than that of other plasma fatty acids.
Topics: 8,11,14-Eicosatrienoic Acid; Arachidonic Acid; Arachidonic Acids; Blood Platelets; Coenzyme A Ligases; Eicosapentaenoic Acid; Esterification; Fatty Acids; Fatty Acids, Unsaturated; Humans; Kinetics; Phospholipids; Repressor Proteins; Saccharomyces cerevisiae Proteins
PubMed: 6308046
DOI: 10.1172/jci110959 -
Journal of Lipid Research Nov 1992A stable essential fatty acid-deficient cell type, known as HepG2-EFD, was derived from the lipoprotein-producing human hepatoma cell line HepG2. These cells are...
A stable essential fatty acid-deficient cell type, known as HepG2-EFD, was derived from the lipoprotein-producing human hepatoma cell line HepG2. These cells are particularly useful for quantitative studies involving essential fatty acids (n-6 and n-3 fatty acids) in secreted lipoproteins. Radiolabeled essential fatty acids can be delivered to these cells without altering the specific activity of the fatty acids, since the deficient cells contain no endogenous essential fatty acids. Using these cells, radioactivity data (dpm) from metabolic studies can be converted directly to mass, and masses as low as a few pmoles can be accurately measured. HepG2-EFD cell cultures were established by growing HepG2 cells in medium containing delipidated serum. After 10 days of growth in delipidated medium, HepG2 cells were completely depleted of all essential fatty acids. Compensatory increases in nonessential fatty acids (n-9 and n-7 fatty acids) including 20:3n-9 (the Mead acid), which is the hallmark fatty acid of essential fatty acid deficiency, were also observed in HepG2-EFD cells. Despite the lack of exogenous fatty acids in the medium and the lack of essential fatty acids in the cells, export of very low density lipoprotein (VLDL)-associated apolipoprotein B by HepG2-EFD was the same as observed for parent HepG2 cells. However, the activity of beta-oxidation of fatty acids in HepG2-EFD cells was much lower than in the parent cell line.(ABSTRACT TRUNCATED AT 250 WORDS)
Topics: Apolipoproteins B; Cell Division; Cell Line; Culture Media; Fatty Acids; Fatty Acids, Essential; Humans; Kinetics; Lipid Metabolism; Models, Biological
PubMed: 1464755
DOI: No ID Found -
The Journal of Biological Chemistry Oct 1984Analysis of neutrophil phospholipids from rats fed an essential fatty acid-deficient diet revealed a 33% reduction in arachidonate and a 90% reduction in linoleate...
Analysis of neutrophil phospholipids from rats fed an essential fatty acid-deficient diet revealed a 33% reduction in arachidonate and a 90% reduction in linoleate compared to neutrophil phospholipids of rats fed a normal diet. The neutrophil phospholipids from rats fed the essential fatty acid-deficient diet also contained significant amounts of 5,8,11-eicosatrienoate, a fatty acid not found in the neutrophils of rats fed a normal diet. Analysis of the production of leukotrienes of the B series by ionophore-stimulated neutrophils from rats fed an essential fatty acid-deficient diet revealed a 87% reduction in leukotriene B4 compared to neutrophils from rats fed a normal diet even though the arachidonate content was reduced by only 34%. Essential fatty acid-deficient neutrophils converted endogenous 5,8,11-eicosatrienoic acid to leukotriene A3 and its nonenzymatic degradation products, but little or no leukotriene B3 was formed. Neutrophils from rats fed a normal diet incubated with ionophore and exogenous 5,8,11-eicosatrienoate also produced leukotriene A3 and its nonenzymatic degradation products but little or no leukotriene B3. Exogenous 5,8,11-eicosatrienoate incubated with ionophore-stimulated normal neutrophils caused a dose-dependent inhibition of leukotriene A hydrolase resulting in diminished production of leukotriene B4 from endogenous arachidonate. Assays of leukotriene A hydrolase in the 10,000 X g supernatant fraction of a homogenate of RBL-1 cells revealed that a lipoxygenase metabolite of 5,8,11-eicosatrienoate rather than 5,8,11-eicosatrienoate itself is the inhibitor of leukotriene A hydrolase. Thus the finding that leukotriene B4 production by neutrophils from essential fatty acid-deficient rats is diminished out of proportion to the decrease in arachidonate content appears to be due to inhibition of leukotriene A hydrolase by a lipoxygenase metabolite.
Topics: 8,11,14-Eicosatrienoic Acid; Animals; Arachidonic Acids; Chemotaxis, Leukocyte; Fatty Acids, Essential; Leukotriene A4; Leukotriene B4; Male; Mass Spectrometry; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Rats; Rats, Inbred Strains; Spectrophotometry, Ultraviolet
PubMed: 6090446
DOI: No ID Found -
Annals of Surgery Mar 1981Essential fatty acid (EFA) deficiency has become a clinical problem since the advent of fat-free total parenteral nutrition (TPN). The following study was done to...
Essential fatty acid (EFA) deficiency has become a clinical problem since the advent of fat-free total parenteral nutrition (TPN). The following study was done to determine the minimum fat requirements for patients receiving continuous TPN solution. Seventy-seven patients who had 97 courses of TPN of at least 14 days duration were prospectively studied. The following fat supplementation was given: a) none, b) 10% soybean oil emulsion intravenously at fixed dosage, c) fat from an oral diet, or d) intravenous and oral fat. No patient was EFA deficient before the onset of TPN. EFA deficiency was prevented when at least 3.2% of total calories were given as intravenous fat or at least 15% as oral fat. Lesser amounts of fat decreased the rate of EFA deficiency development but did not prevent it from occurring. The 7.7 g/day of linoleic acid provided in 1000 ml per week of 10% soybean oil emulsion provides adequate fat to prevent EFA deficiency.
Topics: 8,11,14-Eicosatrienoic Acid; Adolescent; Adult; Aged; Arachidonic Acids; Child; Dietary Fats; Energy Intake; Fat Emulsions, Intravenous; Fatty Acids, Essential; Humans; Middle Aged; Nutritional Requirements; Parenteral Nutrition; Parenteral Nutrition, Total; Prospective Studies
PubMed: 6782957
DOI: 10.1097/00000658-198103000-00009 -
FEBS Letters Feb 19855,8,11-Icosatrienoic acid (20:3n-9), a fatty acid associated with platelet hyperactivity, was oxygenated by platelet lipoxygenase. The end-product of this pathway was...
5,8,11-Icosatrienoic acid (20:3n-9), a fatty acid associated with platelet hyperactivity, was oxygenated by platelet lipoxygenase. The end-product of this pathway was purified by high-performance liquid chromatography (HPLC) and characterized as 12-hydroxy-5,8,10-icosatrienoic acid [12-OH-20:3(5,8,10)] by capillary gas-liquid mass spectrometry. When tested upon platelet aggregation, 12-OH-20:3(5,8,10) exhibited a biphasic effect. At low concentrations (below 5 X 10(-7) M) it potentiated aggregation but inhibited it at higher levels, a pattern similar to that obtained with prostaglandin E2. However, since the amounts of 12-OH-20:3(5,8,10) generated under thrombin stimulation are in the range of concentrations with potentiating effects, it seems that the 12-OH derivative is responsible for the hyperaggrebility of 20:3n-9-rich platelets.
Topics: 8,11,14-Eicosatrienoic Acid; Arachidonate Lipoxygenases; Blood Platelets; Chromatography, High Pressure Liquid; Dinoprostone; Fatty Acids, Unsaturated; Humans; Lipoxygenase; Mass Spectrometry; Platelet Aggregation; Prostaglandins E
PubMed: 3918886
DOI: 10.1016/0014-5793(85)81112-1 -
The Journal of Biological Chemistry Apr 1956
Topics: 8,11,14-Eicosatrienoic Acid; Animals; Fats; Fatty Acids; Fatty Acids, Essential; Lipid Metabolism; Rats
PubMed: 13319291
DOI: No ID Found