Comparison of eight 15-lipoxygenase (LO) inhibitors on the biosynthesis of 15-LO metabolites by human neutrophils and eosinophils

• Published in: PloS one 2018-08, Vol.13 (8), p.e0202424-e0202424
• Main Authors: Archambault, Anne-Sophie, Turcotte, Caroline, Martin, Cyril, Provost, Véronique, Larose, Marie-Chantal, Laprise, Catherine, Chakir, Jamila, Bissonnette, Élyse, Laviolette, Michel, Bossé, Ynuk, Flamand, Nicolas
• Format: Article
• Language: English
• Subjects: 2-Arachidonoylglycerol; Acids; Adenosine; Arachidonate 15-Lipoxygenase - metabolism; Arachidonic acid; Biology and Life Sciences; Biosynthesis; Cannabinoids; Docosahexaenoic acid; Dose-Response Relationship, Drug; Eicosapentaenoic acid; Eicosapentaenoic Acid - analogs & derivatives; Eicosapentaenoic Acid - metabolism; Eosinophils; Eosinophils - metabolism; Female; Glycerol; Humans; Inflammation; Inhibitors; Leukocytes (eosinophilic); Leukocytes (neutrophilic); Linoleic acid; Linolenic acid; Lipids; Lipoxygenase; Lipoxygenase Inhibitors - pharmacology; Male; Medicine and Health Sciences; Metabolites; Neutrophils; Neutrophils - metabolism; Phosphorylation; Substrates; Time Factors
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0202424

Neutrophils and eosinophils are important sources of bioactive lipids from the 5- and the 15-lipoxygenase (LO) pathways. Herein, we compared the effectiveness of humans eosinophils and eosinophil-depleted neutrophils to synthesize 15-LO metabolites using a cocktail of different 15-LO substrates as well as their sensitivities to eight documented 15-lipoxygenase inhibitors. The treatment of neutrophils and eosinophils with linoleic acid, dihomo-γ-linolenic acid, arachidonic acid, eicosapentaenoic acid, docosahexaenoic acid and arachidonyl-ethanolamide, led to the synthesis of 13-HODE, 15-HETrE, 15-HETE, 15-HEPE, 14-HDHA/17-HDHA, and 15-hydroxy-AEA. Neutrophils and eosinophils also metabolized the endocannabinoid 2-arachidonoyl-glycerol into 15-HETE-glycerol, although this required 2-arachidonoyl-glycerol hydrolysis inhibition. Neutrophils and eosinophils differed in regard to dihomo-γ-linolenic acid and linoleic acid utilization with 15-HETrE/13-HODE ratios of 0.014 ± 0.0008 and 0.474 ± 0.114 for neutrophils and eosinophils respectively. 15-LO metabolite synthesis by neutrophils and eosinophils also differed in regard to their relative production of 17-HDHA and 14-HDHA.The synthesis of 15-LO metabolites by neutrophils was concentration-dependent and rapid, reaching a plateau after one minute. While investigating the biosynthetic routes involved, we found that eosinophil-depleted neutrophils express the 15-lipoxygenase-2 but not the 15-LO-1, in contrast to eosinophils which express the 15-LO-1 but not the 15-LO-2. Moreover, 15-LO metabolite synthesis by neutrophils was not inhibited by the 15-LO-1 inhibitors BLX769, BLX3887, and ML351. However, 15-LO product synthesis was partially inhibited by 100 μM NDGA. Altogether, our data indicate that the best 15-LO-1 inhibitors in eosinophils are BLX3887, BLX769, NDGA and ML351 and that the synthesis of 15-LO metabolites by neutrophils does not involve the 15-LO-1 nor the phosphorylation of 5-LO on Ser-663 but is rather the consequence of 15-LO-2 or another unidentified 15-LO.