Effects of Phytoestrogens Genistein and Daidzein on Prostacyclin Production by Human Endothelial Cells

Abstract

The molecular mechanisms of the vascular effects of phytoestrogens are poorly studied. Prostacyclin is a potent vasodilator synthesized by two isoforms of cyclooxygenase (COX) in endothelium. This study examine the effects of two phytoestrogens, the isoflavones genistein and daidzein, on prostacyclin production by cultured human umbilical vein endothelial cells (HUVECs) and the possible role of not only estrogen receptors but also both COX isoforms. The two phytoestrogens significantly increased prostacyclin release in a time-and dosedependent (0.01-1 M) manner, being higher than control after 24 h. Selective inhibitors of COX-1, SC-560 [5-(4-chlorophenyl)-1-(4-methoxypjenyl)-3-(trifluoromethyl)-1H-pyrazole], and COX-2, NS-398 (N-[2-(cyclohexyloxy)-4 nitrophenyl]-methanesulfonamide), were used to investigate the relative contribution of each enzyme. Both inhibitors decreased basal production of prostacyclin, but only COX-2 inhibition completely abolished the isoflavone-stimulated prostacyclin production. Phytoestrogens also increased COX-2 mRNA expression and protein content without affecting COX-1 levels. All these effects were mediated through estrogen receptor activation since treatment of cells with the estrogen receptor antagonist ICI 182780 [7␣-[9[(4,4,5,5,5-pentafluoropentyl)sulfinyl]nonyl]-estra-1,3,5(10)-triene-3,17␤ diol] completely abolished the isoflavone-induced increase in prostacyclin production, COX-2 mRNA expression, and COX-2 protein content. The results clearly support the hypothesis that genistein and daidzein increased HUVEC prostacyclin production through estrogen receptor-dependent mechanism, which involved the enhancement of COX-2 protein and activity.

Estradiol, acting through estrogen receptor alpha, restores dimethylarginine dimethylaminohydrolase activity and nitric oxide production in oxLDL-treated human arterial endothelial cells

“…Cell viability was assessed as previously reported (Hermenegildo et al, 2005). None of the tested experimental conditions showed a percentage of viability on HUAEC lesser than 75% (data not shown).…”

Human umbilical vascular endothelial cells express estrogen receptor beta (ERβ) and progesterone receptor A (PR-A), but not ERα and PR-B

“…Other investigators highlighted estrogenic eVects on volume, growth and elasticity of HUVEC (Hillebrand et al 2006;Morales et al 1995) as well as the release of activation markers like prostacyclin (Hermenegildo et al 2005a;Oviedo et al 2005), nitric oxide (Florian et al 2004), interleukins (Keck et al 1998), vascular cell adhesion molecule-1 (Mukherjee et al 2002;Tatsumi et al 2002) and others (Chen et al 2002;Akarasereenont et al 2000).…”

Astragaloside IV Stimulates Angiogenesis and Increases Hypoxia-Inducible Factor-1α Accumulation via Phosphatidylinositol 3-Kinase/Akt Pathway

“…Primary HUVECs were isolated, grown, and identified, as described earlier (Hermenegildo et al, 2005). HUVECs, at passages between 4 and 8, were cultured in gelatin-coated flasks on medium 199 (M199) (Invitrogen, Carlsbad, CA) that was supplemented with 12.5% fetal bovine serum (FBS) (Invitrogen), 50 U/ml heparin (Shanghai 1 Biochemical Pharmaceutical Co., Shanghai, China), 30 g/ml endothelial cell growth supplement (BD, Franklin Lakes, NJ), 10 ng/ml epidermal growth factor (BD), and 100 U/ml penicillin [Zhongguo Pharmaceutical (Shijiazhuang) Co., Hebei, China] with streptomycin (Northern China Pharmaceutical Co., Shijiazhuang, Hebei, China).…”