Oxygenation of 1‐Docosahexaenoyl Lysophosphatidylcholine by Lipoxygenases; Conjugated Hydroperoxydiene and Dihydroxytriene Derivatives

Abstract

Oxygenation of 1-docosahexaenoyl lysophosphatidylcholine (docosahexaenoyl-lysoPC) by soybean lipoxygenase-1 (LOX-1) or porcine leukocyte LOX was examined. The oxidized products were identified to be hydroperoxydocosahexaenoyl-lysoPC by UV and LC/MS spectrometric analyses. In SP-HPLC and chiral phase-HPLC analyses, the products from the oxygenation of docosahexaenoyl-lysoPC by soybean LOX-1 and porcine leukocyte LOX were found to contain hydroperoxide group mainly at C-17 and C-14, respectively with the S form as a major enantiomer. Next, the sequential exposure of docosahexaenoyl-lysoPC to soybean LOX-1 and porcine leukocyte LOX led to the formation of conjugated triene derivatives possessing a maximal absorption at 271 nm with shoulders at 262 and 281 nm. Based on MS-MS analysis, the conjugated triene derivatives were identified to be 10,17- or 16,17-dihydroxydocosahexaenoyl-lysoPC analogues, suggesting that the diols were produced mainly from hydrolysis of 16,17(S)-epoxide intermediate. In kinetic studies, docosahexaenoyl-lysoPC was more favorable than docosahexaenoic acid as substrate for soybean LOX-1 or leukocyte LOX. Taken together, it is proposed that docosahexaenoyl-lysoPC can be oxygenated as substrates for some lipoxygenases to form conjugated diene and/or triene derivatives.

Prevention of 1-palmitoyl lysophosphatidylcholine-induced inflammation by polyunsaturated acyl lysophosphatidylcholine

“…EIA kits for prostaglandin E 2 (PGE 2 ) and 12-HETE were obtained from Cayman Chemical (Ann Arbor, MI, USA). All kinds of saturated or mono-unsaturated acyl LPCs were obtained from Avanti Polar Lipids Corp. (Alabaster, AL, USA), whereas polyunsaturated acyl LPCs (LPC18:2, LPC20:4, and LPC22:6) were prepared from the corresponding PLA 2 -hydrolyzed PCs as described previously [17,18]. Briefly, PC (2.5 mg), dissolved in chloroform, was dried under N 2 , and then rapidly dispersed in 10 ml of 50 mM borax buffer (pH 9.0) containing 10 mM CaCl 2 .…”

Oral Administration of 2-Docosahexaenoyl Lysophosphatidylcholine Displayed Anti-Inflammatory Effects on Zymosan A-Induced Peritonitis

“…12/15 lipoxygenase (porcine leukocyte, 135.6 units/ ml), 15-lipoxygenase-2 (human recombinant, 250 units/ ml), prostaglandin E 2 (PGE 2 ) and leukotriene C 4 (LTC 4 ) EIA kit were from Cayman Chemical (Ann Arbor, MI, USA). 1-Docosahexaenoyl lysophosphatidylcholine (1-docosahexaenoyl-lysoPC) was prepared from PLA 2 -catalyzed hydrolysis of prevalent didocosahexaenoyl-PC as described previously with slight modification [14,[24][25][26]. In brief, didocosahexaenoyl-PC (2.5 mg), dissolved in chloroform, was dried under N 2 and then rapidly dispersed in 10 ml of 50 mM borax buffer (pH 9.0) containing 10 mM CaCl 2 .…”

“…Briefly, 2-docosahexaenoyl-lysoPC (100 μM) was in turn incubated with soybean LOX-1 (2.5 units/ml), porcine leukocyte 12/15 LOX (1 unit/ml), or human 15-LOX-2 (1 unit/ml) in 50 mM borax buffer (pH 9.0), 50 mM phosphate buffer (pH 7.4) containing 5 mM EDTA and 0.03% Tween 20, or 50 mM Tris-HCl buffer (pH 7.2) containing 0.003% Tween 20, respectively. One unit of LOX was defined as the amount of LOX that can produce 1 nmol of conjugated diene per minute [25,26].…”

“…Finally, the product was analyzed by SP-HPLC system equipped with a silica gel column (10 μM, 300×7.8 mm, Phenomenex, USA), which was eluted (1 ml/min) with an isocratic mobile solvent system, hexane/isopropanol/acetic acid (100:3:0.1), and the effluent was monitored at 234 nm. Finally, the hydrolysis product was identified by co-injection and comparison with 17-hydroxydocoxahexaenoic acid (17-HDoHA) standard [25]. 2), respectively.…”

Transforming Growth Factor-Beta Inhibits Heme Oxygenase-1 Expression in Lung Fibroblasts through Nuclear Factor-Kappa-B-Dependent Pathway

“…Various lipid ligands were also involved in inflammation reactions [29,30,31,32,33,34,35] and pulmonary fibrosis [5,6]. Especially, LPA induced the recruitment and differentiation of fibroblasts [5,8] and regulated endothelial permeability and epithelial barrier functions via activation of its receptors during fibrogenesis.…”