Institute of Animal Biotechnology, College of Animal Science and Technology, Shanxi Agricultural University, Taigu, Shanxi, PR China.
Acta Histochem. 2011 Dec;113(8):771-6. doi: 10.1016/j.acthis.2010.11.005. Epub 2010 Dec 13.
Oocyte-secreted growth differentiation factor (GDF) 9 plays an essential role during follicle maturation through actions on granulosa cells. Despite its critical role in female reproduction, GDF9 expression, signalling and function are less well characterized during spermatogenesis. The purpose of this study was to investigate temporal and spatial expression and potential cellular targets of GDF9 in the adult cat testis. Our result confirmed that GDF9 is stage-specifically localized in the cytoplasm of round spermatids and pachytene spermatocytes of the cat seminiferous epithelium. In particular, activin receptor-like kinase (ALK) 5, the type I receptor of GDF9, is principally localized in the cytoplasm of round spermatids. Smad2/3, signal transducers for GDF9 signalling pathway, is mainly immunolocalized in the cytoplasm of germ cells, Sertoli cells and Leydig cells, but the expression in germ cells are weaker than in Sertoli cells. The expression pattern of ALK5 and Smad2/3 show that GDF9-ALK5-Smad2/3 may not be the only signalling pathway for testicular cell to respond to GDF9. Overall, our results demonstrate that GDF9 is a germ cell-specific factor in the adult cat testis, and that GDF9 regulates the tight junctions of Sertoli cells by paracrine secretion, and regulates the germ cells by autocrine secretion.
卵母细胞分泌的生长分化因子 9（GDF9）通过对颗粒细胞的作用，在卵泡成熟过程中发挥重要作用。尽管 GDF9 在女性生殖中具有关键作用，但它在精子发生过程中的表达、信号传递和功能尚未得到很好的描述。本研究旨在研究 GDF9 在成年猫睾丸中的时空表达和潜在的细胞靶标。我们的结果证实，GDF9 在猫生精上皮的圆形精子和粗线期精母细胞的细胞质中具有特异性定位。特别是，GDF9 的 I 型受体激活素受体样激酶（ALK）5 主要定位于圆形精子的细胞质中。GDF9 信号通路的信号转导物 Smad2/3 主要定位于生精细胞、支持细胞和间质细胞的细胞质中，但在生精细胞中的表达比在支持细胞中的表达弱。ALK5 和 Smad2/3 的表达模式表明，GDF9-ALK5-Smad2/3 可能不是睾丸细胞对 GDF9 反应的唯一信号通路。总的来说，我们的结果表明，GDF9 是成年猫睾丸中一种生殖细胞特异性因子，GDF9 通过旁分泌调节支持细胞的紧密连接，并通过自分泌调节生殖细胞。
