Expression of growth-differentiating factor 9 and its type 1 receptor in human ovaries

Abstract

The expression of growth-differentiating factor 9 (GDF9) has not been studied in ovaries from girls and human fetuses nor has its receptor transforming growth factor-beta1 receptor (TGFbetaR1) been investigated in ovaries of girls/women. The aim of this study was to fill these gaps. Ovarian samples were obtained from 16 human fetuses at 21-35 gestational weeks and from 34 girls/women aged 5-39years. These specimens were prepared for immunohistochemical staining of the GDF9 and TGFbetaR1 proteins. Reverse transcription polymerase chain reaction was used to detect GDF9 mRNA transcripts and in-situ hybridization to localize TGFbetaR1 mRNA transcripts. Positive staining for the GDF9 protein was identified in oocytes and granulosa cells in all samples tested. GDF9 mRNA transcripts were present in all samples. Protein expression of TGFbetaR1 was identified in granulosa cells in all samples. Oocyte staining was identified in samples from girls/women but in only one fetal sample. TGFbetaR1 mRNA transcripts were identified in granulosa cells and oocytes in 50% of the samples from fetuses aged over 22 gestational weeks and in samples from girls/women. The detection of GDF9 and TGFbetaR1 at both at the protein and mRNA levels suggests that GDF9 may have functions in human preantral follicles.

Single-cell expression analysis of BMP15 and GDF9 in mature oocytes and BMPR2 in cumulus cells of women with polycystic ovary syndrome undergoing controlled ovarian hyperstimulation

“…Even though the roles of GDF9 and BMPs during PCOS folliculogenesis have been investigated, gene expression profiles of their receptors in GCs are still unknown. Each ligand of the TGF-β superfamily is known to signal through specific receptor complexes composed of type I and type II serine-threonine kinase receptors in the GC membrane, and BMPR2 has been identified as one of the potential type II receptors involved in BMP15 and GDF9 signaling [16,27,38]. In the present study, mRNA expression of BMPR2 was detected in cumulus cells from PCOS and control patients, but showed no significant differences between them.…”

“…Thus, BMP15 and GDF9 expression in PCOS oocytes remains controversial and the impact of these oocyte-derived factors on oocyte maturation, as well as embryo and pregnancy outcomes, requires further elucidation in PCOS patients. The molecular mechanisms underlying human ovarian pathologies such as premature ovarian failure or PCOS have been extensively studied, and BMP15 and GDF9 are good candidate genes since these two oocytesecreted proteins have been identified as potential biomarkers of ovarian reserve [16]. BMP15, GDF9, and their receptors have been identified already in primordial follicles from various mammalian species, including humans [7,27].…”

“…Transgenic deletions and other modifications in mice [8], sheep [9] and humans [10,11] have provided much of the new information on the mechanisms by which the oocyte affects follicular development [12,13]. The synergistic process of folliculogenesis is regulated mainly by GDF9 and BMP15 as well as their receptors (e.g., BMPR2, TR1, and BMPR1B) [14][15][16][17]. These two members of the TGF-β superfamily are coexpressed in human oocytes and play a fundamental role in granulosa cells steroidogenesis, ovulation, oocyte maturation, and embryo development in mammals [11,18,19].…”

“…Thus, GDF9 activates the type 1 receptor (TGFβRI or activin-like receptor 5(ALK5) [25] and BMP15 activates the BMPRIB receptor or activin-like receptor 6 (ALK6). Following ligand binding, TGFβRI or BMPRIB recruits the BMPR2 that results in phosporylation of the type 1 receptor, which in turn activates the intracellular-signal-mediated (Smad) proteins [16,26,27]. Recently, the BMPR2 has been identified as the receptor that primarily modulates the cooperative effects of GDF9 and BMP15 on rat granulosa cells function, with BMPR2 having the greatest effect on BMP15 suppression of FSHinduced progesterone production [28].…”

Growth and differentiation factor 9 promotes oocyte growth at the primary but not the early secondary stage in three-dimensional follicle culture

“…Whether GDF9 acts directly on the oocyte to induce follicle growth, indirectly through the granulosa cell or both, is not clear, given that both granulosa cells and oocytes in primary follicles express ALK5 [57][58][59][60][61] and BMPR2 [58,62], the reported type I [63,64] and II receptors for GDF9 [65], respectively. However, it is controversial whether ALK5 is the only type I receptor for GDF9 as Alk5 conditional knockout mice have no defects in follicular development and cumulus expansion [62], which is a distinct phenotype from Gdf9 null mice [17].…”