title: Interleukin-13 upregulates vasodilatory 15-lipoxygenase eicosanoids in rabbit aorta.
abstract: OBJECTIVE
  Vasorelaxation of rabbit aorta is mediated by factors released from the vascular endothelium. In the aortic endothelium, arachidonic acid (AA) is metabolized via the 15-lipoxygenase pathway to the vasodilatory compounds 11,12,15-trihydroxyeicosatrienoic acid (THETA) and 15-hydroxy-11,12-epoxyeicosatrienoic acid (HEETA). Interleukin-13 (IL-13) increases 15-lipoxygenase expression and activity in several types of cells. We tested the hypothesis that IL-13 upregulates the 15-lipoxygenase pathway in rabbit aorta by inducing 15-lipoxygenase expression, thus increasing vascular relaxation mediated by THETA and HEETA.
  
  
  RESULTS
  Aorta rings and cultured endothelial cells were treated with IL-13, and 15-lipoxygenase expression was analyzed by reverse transcription-polymerase chain reaction and immunoblotting. 15-Lipoxygenase expression was increased by IL-13 in a concentration- and time-dependent manner. Aortic rings were incubated with [14C]AA, and the metabolites were extracted and resolved by high-performance liquid chromatography. IL-13 treatment increased the production of 15-hydroxyeicosatetraenoic acid, HEETA, and THETA. Indomethacin-resistant vasorelaxation to AA was significantly greater in IL-13-treated vessels than in controls. The relaxation responses to sodium nitroprusside were not altered by IL-13 treatment.
  
  
  CONCLUSIONS
  These data indicate that in the vascular endothelium, IL-13 induces the expression of 15-lipoxygenase and increases the production of the vasodilatory eicosanoids HEETA and THETA.
authors.affiliation: Department of Pharmacology and Toxicology, Medical College of Wisconsin, 8701 Watertown Plank Rd, Milwaukee, WI 53226, USA.
authors.forename: Xin
authors.initials: X
authors.lastname: Tang
authors.forename: Nancy
authors.initials: N
authors.lastname: Spitzbarth
authors.forename: Hartmut
authors.initials: H
authors.lastname: Kuhn
authors.forename: Pavlos
authors.initials: P
authors.lastname: Chaitidis
authors.forename: William B
authors.initials: WB
authors.lastname: Campbell
mesh_terms: D000818:Animals; D001011:Aorta / Q000187:drug effects* / Q000378:metabolism; D001093:Arachidonate 15-Lipoxygenase / Q000378:metabolism*; D016718:Arachidonic Acid / Q000378:metabolism*; D002250:Carbon Radioisotopes; D015777:Eicosanoids / Q000378:metabolism*; D007150:Immunohistochemistry; D018793:Interleukin-13 / Q000494:pharmacology*; D011817:Rabbits; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015854:Up-Regulation; D014664:Vasodilation
chemical_list: D002250:Carbon Radioisotopes; D015777:Eicosanoids; D018793:Interleukin-13; D016718:Arachidonic Acid; D001093:Arachidonate 15-Lipoxygenase