Ding Qingming, Gros Robert, Limbird Lee E, Chorazyczewski Jozef, Feldman Ross D
Department of Vascular Biology Research Group, Robarts Research Institute, University of Western Ontario, London, ON, Canada N6A 5K8.
Am J Physiol Cell Physiol. 2009 Nov;297(5):C1178-87. doi: 10.1152/ajpcell.00185.2009. Epub 2009 Sep 9.
Recent studies suggest that the rapid and nongenomic effects of estradiol may be mediated through the G protein-coupled receptor dubbed GPR30 receptor. The present study examines the role of GPR30 versus a classical estrogen receptor (ERalpha) in mediating the growth regulatory effects of estradiol. GPR30 is readily detectable in freshly isolated vascular tissue but barely detectable in cultured vascular smooth muscle cells (VSMC). In freshly isolated aortic tissue, estradiol stimulated extracellular signal-regulated kinases (ERK) phosphorylation. In contrast, in cultured VSMC, where GPR30 expression is significantly reduced, estradiol inhibits ERK phosphorylation. Transfer of the genes encoding GPR30 led to estradiol stimulation of ERK phosphorylation, which is opposite the effects of estradiol in the primary culture of VSMCs. Transduction of the mineralocorticoid receptor (MR) had no effect on estradiol effects on ERK. Estradiol-mediated stimulation of ERK subsequent to heterologous GPR30 expression was pertussis toxin sensitive and phosphoinositide 3-kinase (PI3 kinase) dependent; under these conditions, estradiol also inhibited protein kinase A (PKA). In contrast, in the absence of GPR30 expression in cultured VSMC, estradiol stimulated PKA activity and inhibited ERK phosphorylation. To determine the functional effect of GPR30 (vs. estrogen receptor expression), we assessed estradiol-mediated apoptosis. In the absence of GPR30 expression, estradiol inhibited apoptosis. This effect was enhanced with ERalpha expression. In contrast, with GPR30 expression, estradiol stimulated apoptosis in an ERK-dependent manner. Thus the effect of estradiol on vascular smooth muscle cell apoptosis is likely dependent on the balance between ER-mediated PKA activation and GPR30-mediated PKA inhibition and PI3 kinase activation. Taken together, we postulate that modulation of GPR30 expression or activity may be an important determinant of the effects of estradiol in the vasculature.
近期研究表明，雌二醇的快速和非基因组效应可能是通过一种名为GPR30受体的G蛋白偶联受体介导的。本研究探讨了GPR30与经典雌激素受体（ERα）在介导雌二醇生长调节效应中的作用。在新鲜分离的血管组织中很容易检测到GPR30，但在培养的血管平滑肌细胞（VSMC）中几乎检测不到。在新鲜分离的主动脉组织中，雌二醇刺激细胞外信号调节激酶（ERK）磷酸化。相反，在培养的VSMC中，GPR30表达显著降低，雌二醇抑制ERK磷酸化。编码GPR30的基因转移导致雌二醇刺激ERK磷酸化，这与雌二醇在VSMC原代培养中的作用相反。盐皮质激素受体（MR）的转导对雌二醇对ERK的作用没有影响。异源GPR30表达后，雌二醇介导的ERK刺激对百日咳毒素敏感且依赖磷脂酰肌醇3激酶（PI3激酶）；在这些条件下，雌二醇还抑制蛋白激酶A（PKA）。相反，在培养的VSMC中缺乏GPR30表达时，雌二醇刺激PKA活性并抑制ERK磷酸化。为了确定GPR30（与雌激素受体表达相比）的功能作用，我们评估了雌二醇介导的细胞凋亡。在缺乏GPR30表达时，雌二醇抑制细胞凋亡。这种作用在ERα表达时增强。相反，在有GPR30表达时，雌二醇以ERK依赖的方式刺激细胞凋亡。因此，雌二醇对血管平滑肌细胞凋亡的影响可能取决于ER介导的PKA激活与GPR30介导的PKA抑制和PI3激酶激活之间的平衡。综上所述，我们推测GPR30表达或活性的调节可能是雌二醇在血管系统中作用的一个重要决定因素。
