Regulatory role of G protein-coupled estrogen receptor for vascular function and obesity

Abstract

We found that the selective stimulation of the intracellular, transmembrane G protein-coupled estrogen receptor (GPER), also known as GPR30, acutely lowers blood pressure after infusion in normotensive rats and dilates both rodent and human arterial blood vessels. Stimulation of GPER blocks vasoconstrictor-induced changes in intracellular calcium concentrations and vascular tone, as well as serum-stimulated cell proliferation of human vascular smooth muscle cells. Deletion of the GPER gene in mice abrogates vascular effects of GPER activation and is associated with visceral obesity. These findings suggest novel roles for GPER in protecting from cardiovascular disease and obesity.

Figures

Figure 1

A, Acute effect of intravenous infusion of acetylcholine (ACh) or increasing doses of G-1 (41.2 ng/kg, 412 ng/kg, 4.12 ug/kg and 20.6 ug/kg) into normotensive Sprague Dawley rats. Y axis values are expressed as percent change of mean arterial pressure. G-1 produced a dose-dependent reduction in blood pressure of 2.6±2%, 10±1%, 13±1%, and 13.5±2.2%, respectively. *P<0.05 vs. control. B, Acute vascular effects of solvent control (ethanol, 0.1%, CTL) and GPER-agonist G-1 (1 μmol/L) on vascular tone in rat mesenteric resistance arteries. Arteries were preconstricted with UTP to induce a stable contraction plateau and exposed to ETOH or G-1, and changes in tone were recorded. At 40 minutes, G-1, reduced vascular tone by 29±4%. n=3-4/group. *P<0.05 vs. control. C, Acute vascular effects of solvent control, 17β-estradiol, or GPER-agonist G-1 on vascular tone in human internal mammary arteries. Arteries were preconstricted with prostaglandin F2α to induce a stable contraction plateau and exposed to solvent control (ethanol 0.3%, CTL), 17β-estradiol or G-1 (both at 3 μ mol/L), and changes in tone were recorded. Both 17β-estradiol and G-1 induced a relaxant response; however, the relaxation in response to G-1 was more potent *P<0.05 vs. CTL, **P<0.05 vs. 17β-estradiol, unpaired t-test, n=4-7/group. D, Acute vascular effects of solvent control (ethanol, 0.3%, CTL), 17β-estradiol, or GPER-agonist G-1 on vascular tone in mouse carotid arteries. Arteries were preconstricted with prostaglandin F2α to induce a stable contraction plateau and exposed to 17β-estradiol or G-1 (both at 3 μ mol/L), and changes in tone were recorded. G-1, but not 17β-estradiol, reduced vascular tone by 44±5%. *P<0.05 vs. solvent, unpaired t-test, n=4-7/group; E, Acute vascular effects of solvent control (ethanol, 0.3%, CTL), 17β-estradiol, or GPER-agonist G-1 on vascular tone in mouse carotid arteries. Arteries were preincubated with 17β-estradiol or G-1 (both at 3 μ mol/L) for 45 minutes and then exposed to serotonin (5HT, 1 μmol/L). G-1 reduced contraction by 39%. *P<0.05 vs. solvent, unpaired t-test, n=4-8/group. F, Left panel: representative original recordings of the effects of intracellular ligand injection on intracellular calcium concentrations in Fura-2-loaded human aortic vascular smooth muscle cells. Solvent had only small effects on intracellular calcium concentrations. Serotonin (5-HT) produced a strong calcium mobilization response. Intracellular injection of G-1 produced a fast and transient increase in calcium concentration, and pretreatment with G-1 completely blunted the subsequent 5-HT-induced changes in intracellular calcium. Right panel: averaged data of 4 experiments. *P<0.05 vs. 5-HT alone, paired t-test, n=4/group. G, Effects of G-1 (10 and 100 nmol/L) on ERK-1/2 phosphorylation in human vascular smooth muscle cells expressing only GPER by Western blot. Left panel, representative example; Right, averaged, n=8/group. *P<0.05 vs. solvent, unpaired t-test. H, Effects of GPER agonists G-1 and ICI 182,780 on serum-stimulated cell proliferation in human vascular smooth muscle cells expressing only GPER. Both agonists reduced cell proliferation between 60% and 80% at concentration of 1000 nmol/L. *P<0.05 vs. solvent, n=6/group

Figure 2

A, Effect of GPER deficiency on body weight in male (left panel) and female (right panel) GPER+/+ (open bars) and GPER-/- mice (hatched bars). *P <0.05 vs. wild-type, Mann-Whitney U test. B, Representative examples of abdominal fat distribution in GPER+/+ (left) and GPER-/- mice (right). Note the almost complete lack of abdominal fat in the wild-type animal compared to the GPER-/- animal. C, Acute vascular effects of solvent control (ethanol, 0.1%, CTL), 17β-estradiol, or GPER-agonist G-1 on vascular tone in carotid arteries of GPER+/+ (left) and GPER-/- mice (right). Arteries were preconstricted with prostaglandin F2α to induce a stable contraction plateau and exposed to 17β-estradiol or G-1 (both at 1 μmol/L), and changes in tone were recorded. G-1 reduced vascular tone in GPER+/+ (left, *P <0.05 vs. solvent, unpaired t-test), but not in GPER-/- mice (right, n.s.). n=6-9/group; D, Contractions to serotonin (100 nmol/L) after preincubation with G-1 (1 μmol/L) in GPER+/+ (left panel) and GPER-/- mice (right panel) *P<0.05 Mann-Whitney U-test, n=5-8/group; *P <0.05 vs. solvent control.