A Biosynthetic Pathway Generating 12-Hydroxy-5,8,14-eicosatrienoic Acid from Arachidonic Acid Is Active in Mouse Skin Microsomes
| Autor: | Setti G. Jagadeesh, John R. Falck, Liping Du, David L. Hachey, Valery Yermalitsky, Diane S. Keeney |
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| Rok vydání: | 2005 |
| Předmět: |
Epoxygenase
Stereochemistry Lipoxygenase Mass Spectrometry Mixed Function Oxygenases Mice chemistry.chemical_compound 8 11 14-Eicosatrienoic Acid Microsomes Animals Cytochrome P450 Family 2 Skin Pharmacology chemistry.chemical_classification Arachidonic Acid biology Epidermis (botany) Fatty acid Stereoisomerism Metabolism Lipid signaling Animals Newborn chemistry Biochemistry biology.protein Microsome Molecular Medicine Arachidonic acid Aryl Hydrocarbon Hydroxylases NADP Chromatography Liquid |
| Zdroj: | Journal of Pharmacology and Experimental Therapeutics. 316:371-379 |
| ISSN: | 1521-0103 0022-3565 |
| Popis: | The epidermis expresses cyclooxygenases, lipoxygenases, and cytochromes P450, which utilize arachidonic acid to generate a diverse array of lipid mediators affecting epidermal cellular differentiation and functions. Recent studies show that mouse epidermis expresses CYP2B19, a keratinocyte-specific epoxygenase that generates 11,12- and 14,15-epoxyeicosatrienoic (EET) acids from arachidonate. We studied CYP2B19-dependent metabolism in mouse epidermal microsomes, reconstituted in the presence of [1-(14)C]arachidonic acid. The majority of the (14)C products formed independently of NADPH, indicative of robust epidermal cyclooxygenase and lipoxygenase activities. We studied two NADPH-dependent products generated in a highly reproducible manner from arachidonate. One of these (product I) coeluted with the CYP2B19 product 14,15-EET on a reversed-phase high-performance liquid chromatography (HPLC) system; there was no evidence for other regioisomeric EET products. Further analyses proved that product I was not an epoxy fatty acid, based on different retention times on a normal-phase HPLC system and failure of product I to undergo hydrolysis in acidic solution. We analyzed purified epidermal (14)C products by liquid chromatography negative electrospray ionization mass spectrometry. Structures of the NADPH-dependent products were confirmed to be 12-oxo-5,8,14-eicosatrienoic acid (I) and 12-hydroxy-5,8,14-eicosatrienoic acid (II). This was the first evidence for a 12-hydroxy-5,8,14-eicosatrienoic acid biosynthetic pathway in mouse epidermis. Epidermal microsomes also generated 12-hydroperoxy, 12-hydroxy, and 12-oxo eicosatetraenoic acids from arachidonate, possible intermediates in the 12-hydroxy-5,8,14-eicosatrienoic acid biosynthetic pathway. These results predict that hydroxyeicosatrienoic acids are synthesized from arachidonate in human epidermis. This would have important implications for human skin diseases given the known pro- and anti-inflammatory activities of stereo- and regioisomeric hydroxyeicosatrienoic acids. |
| Databáze: | OpenAIRE |
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