Identification and absolute configuration of dihydroxy-arachidonic acids formed by oxygenation of 5S-HETE by native and aspirin-acetylated COX-2.

Abstract

Biosynthesis of the prostaglandin endoperoxide by the cyclooxygenase (COX) enzymes is accompanied by formation of a small amount of 11R-hydroxyeicosatetraenoic acid (HETE), 15R-HETE, and 15S-HETE as by-products. Acetylation of COX-2 by aspirin abrogates prostaglandin synthesis and triggers formation of 15R-HETE as the sole product of oxygenation of arachidonic acid. Here, we investigated the formation of by-products of the transformation of 5S-HETE by native COX-2 and by aspirin-acetylated COX-2 using HPLC-ultraviolet, GC-MS, and LC-MS analysis. 5S,15S- dihydroxy (di)HETE, 5S,15R-diHETE, and 5S,11R-diHETE were identified as by-products of native COX-2, in addition to the previously described di-endoperoxide (5S,15S-dihydroxy-9S,11R,8S,12S-diperoxy-6E,13E-eicosadienoic acid) as the major oxygenation product. 5S,15R-diHETE was the only product formed by aspirin-acetylated COX-2. Both 5,15-diHETE and 5,11-diHETE were detected in CT26 mouse colon carcinoma cells as well as in lipopolysaccharide-activated RAW264.7 cells incubated with 5S-HETE, and their formation was attenuated in the presence of the COX-2 specific inhibitor, NS-398. Aspirin-treated CT26 cells gave 5,15-diHETE as the most prominent product formed from 5S-HETE. 5S,15S-diHETE has been described as a product of the cross-over of 5-lipoxygenase (5-LOX) and 15-LOX activities in elicited rat mononuclear cells and human leukocytes, and our studies implicate cross-over of the 5-LOX and COX-2 pathways as an additional biosynthetic route.

• Authors: Surafel Mulugeta, Takashi Suzuki, Noemi Tejera Hernandez, Markus Griesser, William E Boeglin, Claus Schneider
• Journal: Journal of lipid research (J Lipid Res) Vol. 51 Issue 3 Pg. 575-85 (Mar 2010) ISSN: 1539-7262 [Electronic] United States
• PMID: 19752399 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S.)

Chemical References

• Hydroxyeicosatetraenoic Acids
• Cyclooxygenase 2
• Aspirin
• Oxygen

Topics

• Acetylation (drug effects)
• Animals
• Aspirin (chemistry, pharmacology)
• Cell Line
• Circular Dichroism
• Cyclooxygenase 2 (chemistry, metabolism)
• Humans
• Hydroxyeicosatetraenoic Acids (analysis, biosynthesis, chemistry, metabolism)
• Mice
• Oxygen (metabolism)
• Stereoisomerism