Serum- and Feeder-Free Culture of Juvenile Monkey Female Germline Stem Cells and Testosterone Regulation of their Self-Renewal

Background/Aims: The isolation and establishment of female germline stem cells (FGSCs) is controversial because of questions regarding the reliability and stability of the isolation method using antibody targeting mouse vasa homologue (MVH), and the molecular mechanism of FGSCs self-renewal remains unclear. Thus, there needs to be a simple and reliable method for sorting FGSCs to study them. Methods: We applied the differential adhesion method to enrich FGSCs (DA-FGSCs) from mouse ovaries. Through four rounds of purification and 7-9 subsequent passages, DA-FGSC lines were established. In addition, we assessed the role of the phosphoinositide-3 kinase (PI3K)-AKT pathway in regulating FGSC self-renewal. Results: The obtained DA-FGSCs spontaneously differentiated into oocyte-like cells in vitro and formed functional eggs in vivo that were fertilized and produced healthy offspring. AKT was rapidly phosphorylated when the proliferation rate of FGSCs increased after 10 passages, and the addition of a chemical PI3K inhibitor prevented FGSCs self-renewal. Furthermore, over-expression of AKT-induced proliferation and differentiation of FGSCs, c-Myc, Oct-4 and Gdf-9 levels were increased. Conclusions: The differential adhesion method provides a more feasible approach and is an easier procedure to establish FGSC lines than traditional methods. The AKT pathway plays an important role in regulation of the proliferation and maintenance of FGSCs. These findings could help promote stem cell studies and provide a better understanding of causes of ovarian infertility, thereby providing potential treatments for infertility.

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Novel circGFRα1 Promotes Self-Renewal of Female Germline Stem Cells Mediated by m6A Writer METTL14

Frontiers in Cell and Developmental Biology ◽

10.3389/fcell.2021.640402 ◽

2021 ◽

Vol 9 ◽

Author(s):

Xiaoyong Li ◽

Geng Tian ◽

Ji Wu

Keyword(s):

Stem Cells ◽

The Self ◽

Regulatory Mechanisms ◽

Circular Rnas ◽

Germline Stem Cells ◽

Competing Endogenous Rna ◽

Mouse Ovary ◽

Self Renewal ◽

Female Germline ◽

New Evidence

Circular RNAs (circRNAs) play important roles in the self-renewal of stem cells. However, their significance and regulatory mechanisms in female germline stem cells (FGSCs) are largely unknown. Here, we identified an N6-methyladenosine (m6A)-modified circRNA, circGFRα1, which is highly abundant in mouse ovary and stage-specifically expressed in mouse FGSC development. Knockdown of circGFRα1 in FGSCs significantly reduced their self-renewal. In contrast, overexpression of circGFRα1 enhanced FGSC self-renewal. Mechanistically, circGFRα1 promotes FGSC self-renewal by acting as a competing endogenous RNA (ceRNA) that sponges miR-449, leading to enhanced GFRα1 expression and activation of the glial cell derived neurotrophic factor (GDNF) signaling pathway. Furthermore, circGFRα1 acts as a ceRNA based on METTL14-mediated cytoplasmic export through the GGACU motif. Our study should help to understand the mechanisms regulating germ cell development, add new evidence on the mechanism of action of circRNA, and deepen our understanding of the development of FGSCs.

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How Can Female Germline Stem Cells Contribute to the Physiological Neo-Oogenesis in Mammals and Why Menopause Occurs?

Microscopy and Microanalysis ◽

10.1017/s143192761000036x ◽

2010 ◽

Vol 17 (4) ◽

pp. 498-505 ◽

Cited By ~ 11

Author(s):

Antonin Bukovsky

Keyword(s):

Stem Cells ◽

Adult Mouse ◽

Mammalian Species ◽

Reproductive Period ◽

Germline Stem Cells ◽

Environmental Threats ◽

Ovarian Stem Cells ◽

Lower Vertebrates ◽

Female Germline ◽

Prevailing View

AbstractAt the beginning of the last century, reproductive biologists have discussed whether in mammalian species the fetal oocytes persist or are replaced by neo-oogenesis during adulthood. Currently the prevailing view is that neo-oogenesis is functional in lower vertebrates but not in mammalian species. However, contrary to the evolutionary rules, this suggests that females of lower vertebrates have a better opportunity to provide healthy offspring compared to mammals with oocytes subjected to environmental threats for up to several decades. During the last 15 years, a new effort has been made to determine whether the oocyte pool in adult mammals is renewed as well. Most recently, Ji Wu and colleagues reported a production of offspring from female germline stem cells derived from neonatal and adult mouse ovaries. This indicates that both neonatal and adult mouse ovaries carry stem cells capable of producing functional oocytes. However, it is unclear whether neo-oogenesis from ovarian somatic stem cells is physiologically involved in follicular renewal and why menopause occurs. Here we review observations that indicate an involvement of immunoregulation in physiological neo-oogenesis and follicular renewal from ovarian stem cells during the prime reproductive period and propose why menopause occurs in spite of persisting ovarian stem cells.

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