Abstract
Peroxisome proliferator-activated receptor β/δ (PPAR-β) is a ligand-activated transcription factor belonging to the nuclear hormone receptor superfamily that regulates the transcription of many target genes. More recently, acute, nongenomic effects of PPAR-β agonists have also been described. In the present study, we hypothesized that PPAR-β agonists might exert acute nongenomic effects on vascular tone. Here, we report that the structurally unrelated PPAR-β ligands [4-[3-(4-acetyl-3-hydroxy-2-propylphenoxy)propoxy]phenoxy]acetic acid (L-165041) and 4-[[[2-[3-fluoro-4-(trifluoromethyl)phenyl]-4-methyl-5-thiazolyl] methyl]thio]-2-methylphenoxy]acetic acid (GW0742) induced vascular relaxation in phenylephrine-precontracted endothelium-intact rat aortic rings, which was significantly inhibited by endothelial denudation or nitric-oxide synthase (NOS) inhibition with NG-nitro-l-arginine methylester. These relaxant effects reached steady state within 15 min. The relaxation induced by L-165041 and GW0742 in aortic rings precontracted with the thromboxane A2 analog 9,11-dideoxy-11α,9α-epoxymethanoprostaglandin F2α (U-46619) was unaffected either by removal of extracellular calcium or by incubation with calcium-free solution containing the intracellular calcium chelator 1,2-bis-(o-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid tetra(acetoxymethyl) ester. However, the phosphatidylinositol 3-kinase (PI3K) inhibitor 2-(4-morpholinyl)-8-phenyl-1(4H)-benzopyran-4-one hydrochloride (LY-294002) inhibited the endothelium-dependent relaxant responses induced by both PPAR-β agonists. Blockade of PPAR-β with 3-[[[2-methoxy-4-(phenylamino)phenyl]amino]sulfonyl]-2-thiophenecarboxylic acid methyl ester (GSK0660) also partially inhibited these relaxant responses, although PPAR-γ blockade with 2-chloro-5-nitro-N-phenylbenzamide (GW9662) had no effect. In human umbilical vein endothelial cells, L-165041 and GW0742 increased nitric oxide (NO) production and Akt and endothelial NOS (eNOS) phosphorylation, which were sensitive to PI3K inhibition and PPAR-β blockade. In conclusion, the PPAR-β agonists acutely caused vasodilatation, which was partially dependent on endothelial-derived NO. The eNOS activation is calcium-independent and seems to be related to activation of the PI3K-Akt-eNOS pathway.
Footnotes
This work was supported in part by Comisión Interministerial de Ciencia y Tecnología [Grants SAF2007-62731, AGL2007-66108/ALI, SAF2008-03948]; Junta de Andalucía, Proyecto de Excelencia [P06-CTS-01555]; and the Ministerio de Ciencia e Innovación, Instituto de Salud Carlos III [Red HERACLES RD06/0009], Spain.
Article, publication date, and citation information can be found at http://jpet.aspetjournals.org.
doi:10.1124/jpet.109.159806
↵ The online version of this article (available at http://jpet.aspetjournals.org) contains supplemental material.
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ABBREVIATIONS:
- PPAR
- peroxisome proliferator-activated receptor
- VSMC
- vascular smooth muscle cell
- HUVEC
- human umbilical vein endothelial cell
- L-165041
- [4-[3-(4-acetyl-3-hydroxy-2-propylphenoxy)propoxy] phenoxy]acetic acid
- GW0742
- 4-[[[2-[3-fluoro-4-(trifluoromethyl) phenyl]-4-methyl-5-thiazolyl]methyl]thio]-2-methylphenoxy]acetic acid
- NO
- nitric oxide
- eNOS
- endothelial nitric-oxide synthase
- L-NAME
- NG-nitro-l-arginine methylester
- U-46619
- 9,11-dideoxy-11α,9α-epoxymethanoprostaglandin F2α
- BAPTA
- 1,2-bis-(o-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid
- PI3K
- phosphatidylinositol 3-kinase
- LY-294002
- 2-(4-morpholinyl)-8-phenyl-1(4H)-benzopyran-4-one hydrochloride
- GSK0660
- 3-[[[2-methoxy-4-(phenylamino)phenyl]amino]sulfonyl]-2-thiophenecarboxylic acid methyl ester
- GW9662
- 2-chloro-5-nitro-N-phenylbenzamide
- PBS
- physiological buffer saline
- Akt
- protein kinase B
- DAF-2
- diaminofluorescein-2
- A23187
- calcium ionophore calcimycin.
- Received August 2, 2009.
- Accepted November 9, 2009.
- Copyright © 2010 by The American Society for Pharmacology and Experimental Therapeutics
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