Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
Am J Physiol Heart Circ Physiol. 2006 Jan;290(1):H55-63. Epub 2005 Aug 19.

14,15-Dihydroxyeicosatrienoic acid activates peroxisome proliferator-activated receptor-alpha.

Author information

  • 1Dept. of Biochemistry, Univ. of Iowa Carver College of Medicine, Iowa City, IA 52242, USA. xiang-fang@uiowa.edu

Abstract

Epoxyeicosatrienoic acids (EETs), lipid mediators synthesized from arachidonic acid by cytochrome P-450 epoxygenases, are converted by soluble epoxide hydrolase (SEH) to the corresponding dihydroxyeicosatrienoic acids (DHETs). Originally considered as inactive degradation products of EETs, DHETs have biological activity in some systems. Here we examined the capacity of EETs and DHETs to activate peroxisome proliferator-activated receptor-alpha (PPARalpha). We find that among the EET and DHET regioisomers, 14,15-DHET is the most potent PPARalpha activator in a COS-7 cell expression system. Incubation with 10 microM 14,15-DHET produced a 12-fold increase in PPARalpha-mediated luciferase activity, an increase similar to that produced by the PPARalpha agonist Wy-14643 (20 microM). Although 10 microM 14,15-EET produced a threefold increase in luciferase activity, this was abrogated by the SEH inhibitor dicyclohexylurea. 14-Hexyloxytetradec-5(Z)-enoic acid, a 14,15-EET analog that cannot be converted to a DHET, did not activate PPARalpha. However, PPARalpha was activated by 2-(14,15-epoxyeicosatrienoyl)glycerol, which was hydrolyzed and the released 14,15-EET converted to 14,15-DHET. COS-7 cells incorporated 14,15-[3H]DHET from the medium, and the cells also retained a small amount of the DHET formed during incubation with 14,15-[3H]EET. Binding studies indicated that 14,15-[3H]DHET binds to the ligand binding domain of PPARalpha with a Kd of 1.4 microM. Furthermore, 14,15-DHET increased the expression of carnitine palmitoyltransferase 1A, a PPARalpha-responsive gene, in transfected HepG2 cells. These findings suggest that 14,15-DHET, produced from 14,15-EET by the action of SEH, may function as an endogenous activator of PPARalpha.

PMID:
16113065
[PubMed - indexed for MEDLINE]
Free full text
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire
    Loading ...
    Write to the Help Desk