Human neutrophils and eosinophils metabolize polyunsaturated fatty acids and endocannabinoids through the 15-LO pathway.

Human (A) neutrophils (5 × 106 cells/ml) or (B) eosinophils (106 cells/ml) were incubated with 3 μM of AEA or fatty acids, either separately or combined (ALL) during 15 minutes. (C) Catabolism pathways for 2-AG in freshly isolated neutrophils; (D) Neutrophils (5 × 106/ml) were incubated with 3 μM 2-AG or its vehicle (DMSO) for 15 minutes. MAFP 1 μM or its vehicle (DMSO) were added 5 minutes before 2-AG. 15-HETE-G represents the combination of 15-HETE-1-G and 15-HETE-2-G; (E) Neutrophils (5 × 106/ml) were incubated with a cocktail of AEA and fatty acids (LA, DGLA, AA, EPA, and DHA) at 3 μM each for the indicated times. (F) Neutrophils (5 × 106/ml) were incubated with a cocktail of 15-LO metabolites (5 ng of each) for the indicated times. (G) Neutrophils (5 × 106/ml) were incubated with a cocktail of fatty acids and AEA (3 μM of each) or vehicle for 1.5 minutes before the addition of the same cocktail or vehicle for another 1.5 minutes. (A-G) Incubations were stopped by the addition of 1 volume of a cold (-20°C) stop solution (MeOH containing 2 ng of LTB4-D4 and 15-HETE-D8). Samples were processed and analyzed for 15-LO metabolite and LTB4 production as described in Materials and methods. The data represents the mean (± SEM) of 3–5 separate experiments.