BMP15 Gene Is Activated During Human Amniotic Fluid Stem Cell Differentiation into Oocyte-Like Cells

Abstract

The generation of oocyte-like cells (OLCs) from stem cell differentiation in vitro provides an optimal approach for studying the mechanism of oocyte development and maturation. The aim of this study was to investigate the activation of bone morphogenetic protein 15 gene (BMP15) during the differentiation of human amniotic fluid stem cells (hAFSCs) into OLCs. After 15 days of differentiation, OLCs with a diameter of 50-60 μm and zona pellucida (ZP)-like morphology were observed. Reverse transcription-polymerase chain reaction (RT-PCR) analysis showed the BMP15 was activated from approximately day 10 of differentiating hAFSCs and thereafter. The reporter construct pBMP15-enhanced green fluorescent protein (EGFP) was transiently transfected into the differentiated hAFSCs and the EGFP expression driven by the BMP15 promoter was positive in the OLCs. Moreover, RT-PCR analysis showed that the oocyte-specific markers including ZP1, ZP2, ZP3, and c-kit were expressed in the differentiated hAFSCs, and the immunofluorescence assay confirmed that the ZP2 was detected in the OLCs. Quantitative RT-PCR revealed that ZP2 and ZP3 were significantly elevated in the differentiated hAFSCs. Further, in the OLCs derived from hAFSCs, the BMP15 promoter directing the EGFP reporter was colocalized with ZP2. Together, these results illustrated that the BMP15 could be used as an oogenesis marker to track hAFSCs differentiation into the OLCs.

The controversial existence and functional potential of oogonial stem cells

“…Follicle-like structures were successfully differentiated in vitro from hESCs, but these lacked a zona pellucida [26]. Human amniotic fluid stem cells (hAFSCs) were induced to form oocytelike cells in culture in the presence of porcine follicular fluid and expressed EGFP under the BMP15 promoter which was co-localized with ZP2 expression [27]. Studies utilising human cells suggest that the presence of ovarian factors can enhance the ability of stem cells to generate oocytes, however the meiotic and developmental potential of these cells have not been evaluated.…”

Human amniotic fluid stem cells have a potential to recover ovarian function in mice with chemotherapy-induced sterility

“…Furthermore, hAFCs expressed DAZL [12], suggesting potential ability to differentiate into germ cell lineage cells. Recently, Cheng et al reported that human amniotic fluid stem cells cultured in medium containing 5% porcine follicular fluid can differentiate into oocyte-like cells [13]. …”

Emerging Methods to Generate Artificial Germ Cells from Stem Cells1

“…1). Some evidence has shown that germ-like cells can be generated from somatic stem cells derived from mouse [30,31], sheep [32,33], or human [34][35][36] mesenchymal stem cells; fetal mouse skin [37,38] as well as porcine skin [39][40][41][42] or muscle [42,43] stem cells; and human amniotic fluid stem cells [44,45]. Combined, these studies provide examples in which somatic stem cells differentiated into male or female germ cells in culture.…”