Receptors for the 5-oxo class of eicosanoids in neutrophils

5-Hydroxy- and 5-oxo-eicosatetraenoate (5-HETE and 5-oxoETE) activate polymorphonuclear neutrophils (PMNs) through a common, receptor-like recognition system. To define this system, we examined the interaction of these eicosanoids with human PMNs. PMNs esterified 5-[H-3]HETE to glycerolipids at 37 and 4 degrees C. At 37 but not 4 degrees C, the cells also hydroxylated the label to 5,20-[H-3]diHETE. The acyl:CoA synthetase blocker, triacsin C, inhibited esterification but also led to an increase in the hydroxylation of the label. PMNs processed 5-[H-3]oxoETE through the same pathways but only or principally after reducing it to 5-[H-3]HETE (37 or 4 degrees C). In the presence of these varying metabolic reactions, PMNs (37 or 4 degrees C; +/- triacsin C) could not be shown to receptor bind either radiolabel. Plasma membranes isolated from PMNs esterified but unlike whole cells did not reduce or hydroxylate 5-[H-3]oxoETE. Triacsin C blocked esterification, thereby rendering the membranes unable to metabolize this radiolabel. Indeed, triacsin C-treated membranes bound (K-d = 3.8 nM) 5-[H-3]oxoETE specifically and reversibly to 86 pmol of sites per 25 mu g of membrane protein. 5-OxoETE, 5-HETE, and 5,15-diHETE displaced this binding at concentrations correlating with their potency in eliciting PMN Ca2+ transients. GTP and GTP gamma S, but not ATP or ATP gamma S, also reduced 5 [H-3]oxoETE binding, whereas 15-HETE, leukotriene B-4, platelet-activating factor, IL-8, C5a, and N-formyl-Met-Leu-Phe lacked this effect. We conclude that PMNs and their plasma membranes use an acyl:CoA synthetase-dependent route to esterify 5-HETE and 5-oxoETE into lipids. Blockade of the synthetase uncovers cryptic plasmalemma sites that bind 5-oxoETE with exquisite specificity. These sites apparently mediate responses to the 5-oxo class of eicosanoids and are likely members of the serpentine superfamily of G protein-linked receptors.