Effects of Growth Differentiation Factor 9 and Bone Morphogenetic Protein 15 on the in vitro Maturation of Porcine Oocytes

Abstract

Growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) are members of the transforming growth factor-β (TGF-β) family, and their roles in oocyte maturation and cumulus expansion are well known in the mouse and human, but not in the pig. We investigated GDF9 and BMP15 expressions in porcine oocytes during in vitro maturation. A significant increase in the mRNA levels of GDF9 and BMP15 was observed at germinal vesicle breakdown, with expression levels peaking at metaphase I (MI), but decreasing at metaphase II (MII). GDF9 and BMP15 protein localized to the oocyte cytoplasm. While treatment with GDF9 and BMP15 increased the expression of genes involved in both oocyte maturation (c-mos, cyclinb1 and cdc2) and cumulus expansion (has2, ptgs2, ptx3 and tnfaip6), SB431542 (a TGFβ-GDF9 inhibitor) decreased meiotic maturation at MII. Following parthenogenetic activation, the percentage of blastocysts in SB431542 treatment was lower than in the control (41.3% and 74.4%, respectively). Treatment with GDF9 and BMP15 also increased the mRNA levels of maternal genes such as c-mos [a regulatory subunit of mitogen-activated protein kinase (MAPK)], and cyclinb1 and cdc2 [regulatory subunits of maturation/M-phase-promoting factor (MPF)]; however, SB431542 significantly decreased their mRNA levels. These data were supported by poly (A)-test PCR and protein activity analyses. Our results show that GDF9 and BMP15 participate in cumulus expansion and that they stimulate MPF and MAPK activities in porcine oocytes during in vitro maturation.

Increased GDF9 and BMP15 mRNA levels in cumulus granulosa cells correlate with oocyte maturation, fertilization, and embryo quality in humans

“…In animal studies, it has been shown that GDF9 and BMP15 can stimulate oocyte development [24]. Furthermore, mouse oocytes matured with exogenous GDF9 had a higher percentage of hatching blastocysts and a better blastocyst quality, and the number of viable fetuses was also increased [25]. GDF9 and BMP15 play an important role in oocyte development.…”

“…Previous studies have indicated that higher GDF9 and BMP15 levels in the follicular fluid are significantly associated with oocyte maturation and embryo quality [14–16]. In vitro studies have shown that GDF9 and BMP15 may stimulate M-phase-promoting factor (MPF) and mitogen-activated protein kinase (MAPK) activities in oocytes and improve oocyte quality and subsequent developmental potential [17, 18]. In addition, it has been confirmed by many studies that OSFs are expressed both in oocytes and cumulus granulosa cells [19–21].…”

The Role of Glucose Metabolism on Porcine Oocyte Cytoplasmic Maturation and Its Possible Mechanisms

“…The Cdc2/Cdk1 Kinase Assay Kit (MBL, Nagoya, Japan) was used to quantify p34 cdc2 kinase activity [20, 21]. Briefly, thirty oocytes were washed 3 times with sample buffer.…”

Expanded equine cumulus–oocyte complexes exhibit higher meiotic competence and lower glucose consumption than compact cumulus–oocyte complexes

“…This gene has been previously described in the equine species and its expression is 323 enhanced by gonadotropins during follicular maturation and ovulation (Sayasith et It is widely known that GDF9 and BMP15 are involved in cumulus expansion and are related to enhanced meiotic 331 competence (Kidder and Vanderhyden 2010). However, in the horse GDF9 and BMP15 are expressed in the 332 meiosis stage in swine oocytes (Lin et al 2014). In view of these data, our results demonstrate that TNAFIP6 334 could be more reliable than GDF9 or BMP15 to predict complete cumulus expansion as well as the meiotic 335 competence of pooled equine COCs at different meiotic stages.…”