8-11-14-eicosatrienoic-acid and 5-8-14-eicosatrienoic-acid

Biologically active glutathione (GSH) conjugates of oxygenated fatty acids comprise a group of pro- and anti-inflammatory lipid mediators. While arachidonic acid (AA)-derived conjugates, as the cysteinyl leukotrienes (cys-LTs) and eoxins (EXs) have pro-inflammatory properties, conjugates in tissue regeneration (CTRs) biosynthesized from docosahexaenoic acid (DHA) exhibit pro-resolving activity. Human platelets express abundant amounts of platelet-type 12-lipoxygenase (pt12-LOX) and leukotriene C

Topics: 8,11,14-Eicosatrienoic Acid; Arachidonate 12-Lipoxygenase; Blood Platelets; Glutathione; HEK293 Cells; Humans; Mass Spectrometry

The total syntheses of the 5- and 6-fluoro derivatives of 5,8,14-eicosatrienoic (ETA) and arachidonic (AA) acids are described. The fluorinated double bond was introduced using (E)-1,4-dihydroxy-2-fluoro-2-butene obtained through diisobutylaluminium hydride reduction of dimethylfluoromaleate. Recently, 5-fluoro and 6-fluoro arachidonic acids (5-F-AA and 6-F-AA) were found to be effective inhibitors of 5-lipoxygenase in vitro (Nave, J. F.; Jacobi, D.; Gaget, C.; Dulery, B.; Ducep, J. B., Biochem. J. 1991, 278, 549). The effect of these compounds on leukotriene C4 (LTC4) production by intact cells was investigated. Mouse peritoneal macrophages were cultured in the presence of 5-F-AA or 6-F-AA under conditions where AA was found to be efficiently incorporated into cellular phospholipids. Following stimulation with zymosan, macrophages treated with 20 microM 6-F-AA released 30 to 35% less LTC4 than control cells. In contrast, macrophages treated with 20 microM 5-F-AA released 1.5 to 1.8 times more LTC4 than control cells. In competition experiments with [14C]-AA, 5-F-AA modified the distribution profile of [14C]-AA within the various classes of lipids in a way similar to AA. 6-F-AA had a distinct behaviour, producing a more important incorporation of [14C]-AA into the neutral lipid fraction at the expense of the phospholipid fraction than AA and 5-F-AA. 6-F-AA is expected to be an important tool in further studies of the arachidonic acid pathway in vivo.

Topics: 8,11,14-Eicosatrienoic Acid; Animals; Arachidonic Acids; Fluorides; In Vitro Techniques; Leukotriene C4; Lipid Metabolism; Lipids; Macrophages, Peritoneal; Male; Mice; Molecular Structure

The 5- and 6-fluoro derivatives of arachidonic acid (5F-ETE and 6F-ETE) were evaluated as substrates of rat basophilic leukaemia cell (RBL-1) 5-lipoxygenase. 5F-ETE was found to be a poor substrate and was converted into a single product, 5-oxoeicosa-6,8,11,14-tetraenoic acid (5-oxo-ETE). 6F-ETE was a good substrate and was mainly converted into 5-hydroperoxy-6-fluoroeicosa-6,8,11,14-tetraenoic acid (5-OOH-6F-ETE) with concomitant formation of a small amount of 5-oxo-6-fluoroeicosa-6,8,11,14-tetraenoic acid (5-oxo-6F-ETE). However the formation of 5,12-dihydroxy-6-fluoroeicosa-6,8,10,14-tetraenoic acids, epimeric at C-12, was not observed. Eicosa-5(Z),8(Z),14(Z)-trienoic acid (ET), previously described as a good substrate of 5-lipoxygenase, is oxidized mainly to 5-hydroperoxyeicosa-6,8,14-trienoic acid (5-OOH-ET), which does not serve as a substrate for the leukotriene A4 (LTA4) synthase activity of 5-lipoxygenase [Navé, Dulery, Gaget & Ducep (1988) Prostaglandins 36, 385-398]. To allow a better estimation of the effect of fluorine substitution on the rate of oxidation of the 5,8-cis,cis-diene moiety by 5-lipoxygenase, the 5- and 6-fluoro derivatives of ET were studied as substrates. Qualitatively, the metabolism of 5F-ET and 6F-ET was found to be similar to that observed for 5F-ETE and 6F-ETE. Quantitatively, 6F-ET proved to be a somewhat better substrate than ET, whereas 5F-ET was poorly metabolized. The relative ability of arachidonic acid, ET and the corresponding 5- and 6-fluoro derivatives to inhibit the 5-lipoxygenase-catalysed oxidation of eicosa-5(Z),8(Z)-dienoic acid (ED) was also investigated. 6F-ETE and 5F-ETE were found to be effective and about equipotent inhibitors of 5-lipoxygenase in the micromolar range. In view of their close structural similarity to arachidonic acid, these two inhibitors are expected to be important tools in the study of the 5-lipoxygenase pathway in vivo.

Topics: 8,11,14-Eicosatrienoic Acid; Arachidonate 5-Lipoxygenase; Arachidonic Acids; Catalysis; Chromatography, High Pressure Liquid; Fluorides; Free Radicals; Lipoxygenase Inhibitors; Substrate Specificity

5,8,14-eicosatrienoic (5,8,14-ETA) and 5,8-eicosadienoic (5,8-EDA) acids are converted by the 5-lipoxygenase from RBL-1 cells into 5-hydroperoxy-6,8,14-eicosatrienoic (5-OOH-ETA) and 5-hydroperoxy-6,8-eicosadienoic (5-OOH-EDA) acids, respectively. These hydroperoxy fatty acids, unlike 5-hydroperoxy-6,8,11,14-eicosatetraenoic acid (5-HPETE), are not further processed into leukotrienes by the leukotriene A4 synthase activity of 5-lipoxygenase. 5,8,14-ETA was used to establish the saturation kinetics of 5-lipoxygenase in the 100,000g supernatant from RBL-1 cells. The study was performed by measuring the rate of product formation at optimal concentrations of the cofactors, calcium and ATP. Kinetics performed at various concentrations of supernatant did not follow the Michaelis-Menten equation. This aspect is discussed in relation to the presence of hydroperoxide-reducing system(s) in the supernatant. 5,8,14-ETA and 5,8-EDA turnover rates were also compared.

Topics: 8,11,14-Eicosatrienoic Acid; Animals; Arachidonate 5-Lipoxygenase; Arachidonate Lipoxygenases; Arachidonic Acids; Cells, Cultured; Kinetics