title: Eicosanoid biosynthesis in an advanced deuterostomate invertebrate, the sea squirt (Ciona intestinalis).
abstract: The eicosanoid generating potential of tunic, branchial basket, intestine, ovary and tadpole larvae from the sea squirt, Ciona intestinalis, was examined using a combination of reverse phase high performance liquid chromatography, gas chromatography-mass spectrometry and enzyme immunoassay. All organs examined synthesized the lipoxygenase products 12-hydroxyeicosapentaenoic acid (12-HEPE) and 8-HEPE implying that both 8- and 12-lipoxygenase activity are widely distributed in this species. In addition, tunic and branchial basket generated significant amounts of 8,15-diHEPE and smaller amounts of 8,15-dihydroxyeicosatetraenoic acid (8,15-diHETE), while tunic alone generated small amounts of conjugated tetraene-containing material with a UV chromophore and mass ion characteristic of a lipoxin-like compound. The broad range lipoxygenase inhibitors, esculetin and nordihydroguaiaretic acid, both caused a significant dose dependent inhibition of 12-HEPE and 8,15-diHEPE biosynthesis in tunic, while the specific 5-lipoxygenase inhibitor, REV-5901, and the specific 5-lipoxygenase activating protein inhibitor, MK-866, had no observable effect on the lipoxygenase profile of this tissue. Tunic, branchial basket, intestine and ovary all generated significant amounts of prostaglandin (PG) E and PGF immunoreactive material and smaller amounts of thromboxane B immunoreactive material as measured by enzyme immunoassay. The non-specific cyclooxygenase (COX) inhibitor, indomethacin, the selective COX-1 inhibitors, resveratrol and valerylsalicylate, and the specific COX-2 inhibitors, NS-398, etolodac and DFU (5,5-dimethyl-3-(3-fluorophenyl)-4-(4-methylsulphonyl) phenyl-2(5H)-furanone) all caused a significant dose dependent inhibition of the biosynthesis of PGE immunoreactive material. However, the specific COX-2 inhibitors were most effective, perhaps implying that a COX-2-like enzyme may be present in this species.
authors.affiliation: School of Biological Sciences, University of Wales Swansea, Singleton Park, UK.
authors.forename: J
authors.initials: J
authors.lastname: Knight
authors.forename: G W
authors.initials: GW
authors.lastname: Taylor
authors.forename: P
authors.initials: P
authors.lastname: Wright
authors.forename: A S
authors.initials: AS
authors.lastname: Clare
authors.forename: A F
authors.initials: AF
authors.lastname: Rowley
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid; D002938:Ciona intestinalis / Q000187:drug effects / Q000378:metabolism*; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D015777:Eicosanoids / Q000096:biosynthesis* / Q000737:chemistry / Q000302:isolation & purification; D015118:Eicosapentaenoic Acid / Q000031:analogs & derivatives / Q000096:biosynthesis; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D007975:Leukotriene B4 / Q000031:analogs & derivatives / Q000096:biosynthesis; D016859:Lipoxygenase Inhibitors / Q000494:pharmacology; D015394:Molecular Structure; D014018:Tissue Distribution