Wang Yao, Nicholls Peter K, Stanton Peter G, Harrison Craig A, Sarraj Mai, Gilchrist Robert B, Findlay Jock K, Farnworth Paul G
Prince Henry's Institute of Medical Research, PO Box 5152, Clayton, Victoria 3168, Australia.
J Endocrinol. 2009 Sep;202(3):419-30. doi: 10.1677/JOE-08-0563. Epub 2009 Jun 8.
Growth differentiation factor 9 (GDF9) produced within the ovary plays an essential role during follicle maturation through actions on granulosa cells, but extra-ovarian expression, signalling and actions of GDF9 are less well characterised. The present studies confirm GDF9 expression in the mouse testis, pituitary gland and adrenocortical cancer (AC) cells, and establish its expression in L beta T2 gonadotrophs, and in mouse adrenal glands, particularly foetal and neonatal cortical cells. AC, L beta T2, TM3 Leydig and TM4 Sertoli cells express the requisite GDF9 binding signalling components, particularly activin receptor-like kinase (ALK) 5 and the bone morphogenetic protein (BMP)/GDF type II receptor, BMPRII (BMPR2). We therefore compared GDF9 activation of these potential extra-ovarian target cell types with its activation of granulosa cells. Recombinant mouse GDF9 stimulated expression of activin/transforming growth factor-beta-responsive reporters, pGRAS-luc or pAR3-lux, in TM4 and AC cells (IC50=145 ng/ml in the latter case), and two granulosa cell lines, KGN and COV434. The ALK4/5/7 inhibitor, SB431542, blocked GDF9 activity in each case. By contrast, GDF9 lacked specific effects on TM3 cells and rat primary pituitary and mouse L beta T2 gonadotrophs. Our findings show that GDF9 regulates the expression of R-SMAD2/3-responsive reporter genes through ALK4, 5 or 7 in extra-ovarian (adrenocortical and Sertoli) cells with similar potency and signalling pathway to its actions on granulosa cells, but suggest that expression of BMPRII, ALK5 (TGFBR1) and R-SMADs 2 and 3 may not be sufficient for a cell to respond to GDF9.
卵巢内产生的生长分化因子9（GDF9）通过作用于颗粒细胞在卵泡成熟过程中发挥重要作用，但GDF9在卵巢外的表达、信号传导和作用尚未得到充分表征。本研究证实了GDF9在小鼠睾丸、垂体和肾上腺皮质癌（AC）细胞中的表达，并确定了其在LβT2促性腺激素细胞以及小鼠肾上腺，特别是胎儿和新生儿皮质细胞中的表达。AC细胞、LβT2细胞、TM3 Leydig细胞和TM4 Sertoli细胞表达必需的GDF9结合信号成分，特别是激活素受体样激酶（ALK）5和骨形态发生蛋白（BMP）/GDF II型受体BMPRII（BMPR2）。因此，我们比较了GDF9对这些潜在的卵巢外靶细胞类型的激活作用与其对颗粒细胞的激活作用。重组小鼠GDF9刺激了TM4细胞和AC细胞（后者的IC50 = 145 ng/ml）以及两种颗粒细胞系KGN和COV434中激活素/转化生长因子-β反应性报告基因pGRAS-luc或pAR3-lux的表达。ALK4/5/7抑制剂SB431542在每种情况下均阻断了GDF9的活性。相比之下，GDF9对TM3细胞、大鼠原代垂体和小鼠LβT2促性腺激素细胞没有特异性作用。我们的研究结果表明，GDF9通过ALK4、5或7在卵巢外（肾上腺皮质和支持细胞）细胞中调节R-SMAD2/3反应性报告基因的表达，其效力和信号通路与其对颗粒细胞的作用相似，但表明BMPRII、ALK5（TGFBR1）和R-SMADs 2和3的表达可能不足以使细胞对GDF9产生反应。
