Introduction:
GPR30 is an intracellular transmembrane G protein-coupled receptor that mediates non-genomic estrogen signaling. The GPR30 agonist G-1 modulates glucose homeostasis and vascular function. However, its impact on vascular inflammation and atherogenesis has not yet been investigated in the atherosclerotic apolipoprotein E-deficient(ApoE-/-) mouse model.

Material and methods:
ApoE-/- mice were fed a high-cholesterol diet for 7 weeks while being treated with the selective GPR30 agonist G-1 (n=6-7). After the treatment period, vascular relaxation capacity, vascular oxidative stress, and atherosclerotic plaque burden were assessed. In vitro, reactive oxygen species, expression levels of the angiotensin II type1(AT1) receptor, and proliferation rate were quantified in human coronary artery smooth muscle cells(HCASMC).

Results:
G-1 significantly improved glucose tolerance in vivo (142.2±8.1mg/dl vs. 204.6±13.3mg/dl), G-1 reduced vascular oxidative stress (221±88RLU/s/mg vs.1,983±885RLU/s/mg) and improved endothelium-dependent vasodilation (relaxation to 35.1±4.5% vs.63.0±4.6%). Furthermore, treatment with G-1 significantly reduced the atherosclerotic plaque burden of female ApoE-/- mice (56.5±3.7% vs.75.5±2.9%). In vitro, G-1 provoked a significant downregulation of the AT1 receptor in HCASMC (0.67±0.09-fold). Furthermore, G-1 blunted angiotensin II-induced ROS production by HCASMC (817±7RLU/s/mg vs.1,625±105 RLU/s/mg) and diminished HCASMC proliferation (-26.8±2.7% vs.+50.4±1.7%).

Conclusions:
Selective GPR30 activation improves glucose tolerance in vivo and decreases vascular ROS production in vitro and in vivo. In vitro, the antioxidant effect might be mediated by downregulation of the AT1 receptor. In vivo, the antioxidant effect of G-1 is associated with an improved endothelial function and a reduced atherosclerotic plaque burden in ApoE-deficient mice, indicating beneficial vascular effects of GPR30 activation. GPR30 agonism might thus be a compelling treatment strategy against atherosclerosis.