Wang Cheng, Prossnitz Eric R, Roy Shyamal K
Department of Obstetrics-Gynecology, University of Nebraska Medical Center, Omaha, Nebraska 68198-4515, USA.
Endocrinology. 2008 Sep;149(9):4452-61. doi: 10.1210/en.2008-0441. Epub 2008 May 22.
Estradiol-17beta (E2) plays an important role in the formation and development of primordial follicles, but the mechanisms remain unclear. G protein-coupled receptor 30 (GPR30) can mediate a rapid and transcription-independent E2 signaling in various cells. The objectives of this study were to examine whether GPR30 was expressed in the neonatal hamster ovary and whether it could mediate estrogen action during the formation of primordial follicles. GPR30 mRNA levels decreased from the 13th day of gestation (E13) through the second day of postnatal (P2) life, followed by steady increases from P3 through P6. Consistent with the changes in mRNA levels, GPR30 protein expression decreased from E13 to P2 followed by a significant increase by P7, the day before the first appearance of primordial follicles in the hamster ovary. GPR30 was expressed both in the oocytes and somatic cells, although the expression in the oocytes was low. GPR30 protein was located primarily in the perinuclear endoplasmic reticulum, which was also the site of E2-BSA-FITC (E2-BSA-fluorescein isothiocyanate) binding. E2 or E2-BSA increased intracellular calcium in neonatal hamster ovary cells in vitro. Exposure to GPR30 small interfering RNA in vitro significantly reduced GPR30 mRNA and protein levels in cultured hamster ovaries, attenuated E-BSA binding to cultured P6 ovarian cells, and markedly suppressed estrogen-stimulated primordial follicle formation. These results suggest that a membrane estrogen receptor, GPR30, is expressed in the ovary during perinatal development and mediates E2 action on primordial follicle formation.
17β-雌二醇（E2）在原始卵泡的形成和发育中起重要作用，但其机制尚不清楚。G蛋白偶联受体30（GPR30）可在多种细胞中介导快速且不依赖转录的E2信号传导。本研究的目的是检测GPR30是否在新生仓鼠卵巢中表达，以及它是否能在原始卵泡形成过程中介导雌激素作用。从妊娠第13天（E13）到出生后第2天（P2），GPR30 mRNA水平下降，随后从P3到P6稳步上升。与mRNA水平的变化一致，GPR30蛋白表达从E13到P2下降，随后在P7（仓鼠卵巢中首次出现原始卵泡的前一天）显著增加。GPR30在卵母细胞和体细胞中均有表达，尽管卵母细胞中的表达较低。GPR30蛋白主要位于核周内质网，这也是E2-牛血清白蛋白-异硫氰酸荧光素（E2-BSA-FITC）结合的部位。在体外，E2或E2-BSA可增加新生仓鼠卵巢细胞内的钙浓度。体外暴露于GPR30小干扰RNA可显著降低培养的仓鼠卵巢中GPR30 mRNA和蛋白水平，减弱E-BSA与培养的P6卵巢细胞的结合，并显著抑制雌激素刺激的原始卵泡形成。这些结果表明，一种膜雌激素受体GPR30在围产期发育期间在卵巢中表达，并介导E2对原始卵泡形成的作用。
