Esterified eicosanoids are acutely generated by 5-lipoxygenase in primary human neutrophils and in human and murine infection

Abstract

Abstract5-Lipoxygenase (5-LOX) plays key roles in infection and allergic responses. Herein, four 5-LOX–derived lipids comprising 5-hydroxyeicosatetraenoic acid (HETE) attached to phospholipids (PLs), either phosphatidylethanolamine (PE) or phosphatidylcholine (18:0p/5-HETE-PE, 18:1p/5-HETE-PE, 16:0p/5-HETE-PE, and 16:0a/5-HETE-PC), were identified in primary human neutrophils. They formed within 2 minutes in response to serum-opsonized Staphylococcus epidermidis or f-methionine-leucine-phenylalanine, with priming by lipopolysaccharide, granulocyte macrophage colony-stimulating factor, or cytochalasin D. Levels generated were similar to free 5-HETE (0.37 ± 0.14 ng vs 0.55 ± 0.18 ng/106 cells, esterified vs free 5-HETE, respectively). They remained cell associated, localizing to nuclear and extranuclear membrane, and were formed by fast esterification of newly synthesized free 5-HETE. Generation also required Ca2+, phospholipase C, cytosolic and secretory phospholipase A2, 5-LOX activating protein, and mitogen-activated protein kinase/extracellular signal-regulated kinase kinase 1. 5-HETE-PLs were detected in murine S epidermidis peritonitis, paralleling neutrophil influx, and in effluent from Gram-positive human bacterial peritonitis. Formation of neutrophil extracellular traps was significantly enhanced by 5-LOX inhibition but attenuated by HETE-PE, whereas 5-HETE-PE enhanced superoxide and interleukin-8 generation. Thus, new molecular species of oxidized PL formed by human neutrophils during bacterial infection are identified and characterized.