scholarly journals Estradiol, Progesterone, and Genistein Inhibit Oocyte Nest Breakdown and Primordial Follicle Assembly in the Neonatal Mouse Ovary in Vitro and in Vivo

Endocrinology ◽  
2007 ◽  
Vol 148 (8) ◽  
pp. 3580-3590 ◽  
Author(s):  
Ying Chen ◽  
Wendy N. Jefferson ◽  
Retha R. Newbold ◽  
Elizabeth Padilla-Banks ◽  
Melissa E. Pepling

In developing mouse ovaries, oocytes develop as clusters of cells called nests or germ cell cysts. Shortly after birth, oocyte nests dissociate and granulosa cells surround individual oocytes forming primordial follicles. At the same time, two thirds of the oocytes die by apoptosis, but the link between oocyte nest breakdown and oocyte death is unclear. Although mechanisms controlling breakdown of nests into individual oocytes and selection of oocytes for survival are currently unknown, steroid hormones may play a role. Treatment of neonatal mice with natural or synthetic estrogens results in abnormal multiple oocyte follicles in adult ovaries. Neonatal genistein treatment inhibits nest breakdown suggesting multiple oocyte follicles are nests that did not break down. Here we investigated the role of estrogen signaling in nest breakdown and oocyte survival. We characterized an ovary organ culture system that recapitulates nest breakdown, reduction in oocyte number, primordial follicle assembly, and follicle growth in vitro. We found that estradiol, progesterone, and genistein inhibit nest breakdown and primordial follicle assembly but have no effect on oocyte number both in organ culture and in vivo. Fetal ovaries, removed from their normal environment of high levels of pregnancy hormones, underwent premature nest breakdown and oocyte loss that was rescued by addition of estradiol or progesterone. Our results implicate hormone signaling in ovarian differentiation with decreased estrogen and progesterone at birth as the primary signal to initiate oocyte nest breakdown and follicle assembly. These findings also provide insight into the mechanism of multiple oocyte follicle formation.

Endocrinology ◽  
2007 ◽  
Vol 148 (4) ◽  
pp. 1707-1716 ◽  
Author(s):  
Cheng Wang ◽  
Shyamal K. Roy

The role of E2 on primordial follicle formation was examined by treating neonatal hamsters with 1 or 2 μg estradiol cypionate (ECP) at age postnatal d 1 (P1) and P4 or by in vitro culture of embryonic d 15 (E15) ovaries with 1, 5, or 10 ng/ml estradiol-17β (E2). The specificity of E2 action was examined by ICI 182,780. One microgram of ECP maintained serum levels of E2 within the physiological range, significantly reduced apoptosis, and stimulated the formation and development of primordial follicles. In contrast, 2 μg ECP increased serum E2 levels to 400 pg/ml and had significantly less influence on primordial follicle formation. In vivo, ICI 182,780 significantly increased apoptosis and caused a modest reduction in primordial follicle formation. The formation and development of primordial follicles in vitro increased markedly with 1 ng/ml E2, and the effect was blocked by ICI 182,780. Higher doses of E2 had no effect on primordial follicle formation but significantly up-regulated apoptosis, which was blocked by ICI 182,780. CYP19A1 mRNA expression occurred by E13 and increased with the formation of primordial follicles. P4 ovaries synthesized E2 from testosterone, which increased further by FSH. Both testosterone and FSH maintained ovarian CYP19A1 mRNA, but FSH up-regulated the expression. These results suggest that neonatal hamster ovaries produce E2 under FSH control and that E2 action is essential for the survival and differentiation of somatic cells and the oocytes leading to the formation and development of primordial follicles. This supportive action of E2 is lost when hormone levels increase above a threshold.


Author(s):  
Ren Tanimoto ◽  
Kyota Yoshida ◽  
Shinya Ikeda ◽  
Yayoi Obata

AbstractIn vitro systems capable of reconstituting the process of mouse oogenesis are now being established to help develop further understanding of the mechanisms underlying oocyte/follicle development and differentiation. These systems could also help increase the production of useful livestock or genetically modified animals, and aid in identifying the causes of infertility in humans. Recently, we revealed, using an in vitro system for recapitulating oogenesis, that the activation of the estrogen signaling pathway induces abnormal follicle formation, that blocking estrogen-induced expression of anti-Müllerian hormone is crucial for normal follicle formation, and that the production of α-fetoprotein in fetal liver tissue is involved in normal in vivo follicle formation. In mouse fetuses, follicle formation is not carried out by factors within the ovaries but is instead orchestrated by distal endocrine factors. This review outlines findings from genetics, endocrinology, and in vitro studies regarding the factors that can affect the formation of primordial follicles in mammals.


Reproduction ◽  
2008 ◽  
Vol 136 (6) ◽  
pp. 703-715 ◽  
Author(s):  
H M Picton ◽  
S E Harris ◽  
W Muruvi ◽  
E L Chambers

The development of technologies to grow oocytes from the most abundant primordial follicles to maturity in vitro holds many attractions for clinical practice, animal production technology and research. The production of fertile oocytes and live offspring has been achieved in mice following the long-term culture of oocytes in primordial follicles from both fresh and cryopreserved ovarian tissue. In contrast, in non-rodent species advances in follicle culture are centred on the growth of isolated preantral follicles. As a functional unit, mammalian preantral follicles are well-suited to culture but primordial and primary follicles do not grow well after isolation from the ovarian stroma. The current challenges for follicle culture are numerous and include: optimisation of culture media and the tailoring of culture environments to match the physiological needs of the cell in vivo; the maintenance of cell–cell communication and signalling during culture; and the evaluation of the epigenetic status, genetic health and fertility of in vitro derived mature oocytes. In large animals and humans, the complete in vitro growth and maturation of oocytes is only likely to be achieved following the development of a multistage strategy that closely mimics the ovary in vivo. In this approach, primordial follicle growth will be initiated in situ by the culture of ovarian cortex. Isolated preantral follicles will then be grown to antral stages before steroidogenic function is induced in the somatic cells. Finally, cytoplasmic and nuclear maturation will be induced in the in vitro derived oocytes with the production of fertile metaphase II gametes.


2020 ◽  
Vol 11 (9) ◽  
Author(s):  
Xiaowen Sun ◽  
Francesca Gioia Klinger ◽  
Jing Liu ◽  
Massimo De Felici ◽  
Wei Shen ◽  
...  

Abstract Primordial follicle pool provides all available oocytes throughout the whole reproductive life span. Abnormal regulation in primordial follicle assembly leads to abnormal size of primordial follicle pool, even causes infertility. Here, miR-378-3p was proved to regulate mouse primordial follicle assembly both in vivo and in vitro. The expression of miR-378-3p significantly increased in mice ovaries from 17.5 dpc (days post coitum) up to 3 dpp (day post partum) compared with the expression of 16.5 dpc ovaries, which suggested that miR-378-3p was involved in primordial follicle assembly. To uncover the underlying mechanism, newborn mice ovaries were cultured in vitro in the presence of rapamycin and 3-methyladenine, which showed that the expression of miR-378-3p changed together with the percentage of primordial follicle. Moreover, during the normal process of primordial follicle assembly between 17.6 dpc and 3 dpp, autophagy is activated, while, apoptosis is inhibited. The in vivo results showed that newborn mice starved for 1.5 days showing the increased miR-378-3p, activated autophagy and inhibited apoptosis in the ovaries, had more percentage of primordial follicles. Over-expression of miR-378-3p using miR-378-3p agomir caused increased percentage of primordial follicle, increased level of autophagy, and decreased level of apoptosis. Knockdown of miR-378-3p by miR-378-3p antiagomir had the opposite results. Using pmirGLO Dual-Luciferase miRNA Target Expression system, we confirmed both PDK1 and Caspase9 were targets of miR-378-3p, which suggested that miR-378-3p activated autophagy by targeting PDK1 and inhibited apoptosis by targeting Caspase9. MiR-378-3p could be used as a biomarker of diseases caused by abnormal size of primordial follicle pool for diagnosis, prevention, or therapy.


Endocrinology ◽  
2009 ◽  
Vol 151 (3) ◽  
pp. 1310-1319 ◽  
Author(s):  
Fuminori Kimura ◽  
Yisrael Sidis ◽  
Lara Bonomi ◽  
Yin Xia ◽  
Alan Schneyer

Follistatin (FST) is a natural antagonist of activin and related TGFβ superfamily ligands that exists as three protein isoforms differing in length at the C terminus. The longest FST315 isoform is found in the circulation, whereas the shortest FST288 isoform is typically found in or on cells and tissues, and the intermediate FST303 isoform is found in gonads. We recently demonstrated that the FST isoforms have distinct biological actions in vitro that, taken together with the differential distribution, suggests they may also have different roles in vivo. To explore the specific role of individual FST isoforms, we created a single-isoform FST288-only mouse. In contrast to the neonatal death of FST global knockout mice, FST288-only mice survive to adulthood. Although they appear normal, FST288-only mice have fertility defects including reduced litter size and frequency. Follicles were counted in ovaries from 8.5- to 400-d-old females. Significantly fewer morphologically healthy antral follicles were found in 100- to 250-d FST288-only ovaries, but there were significantly more secondary, primary, and primordial follicles detected at d 8.5 in FST288-only ovaries. However, depletion of this primordial follicle pool is more rapid in FST288-only females resulting in a deficit by 250 d of age and early cessation of reproduction. Superovulated FST288-only females have fewer ovulated eggs and embryos. These results indicate that the FST isoforms have different activities in vivo, that the FST288-only isoform is sufficient for development, and that loss of FST303 and FST315 isoforms results in fertility defects that resemble activin hyperactivity and premature ovarian failure.


Endocrinology ◽  
2003 ◽  
Vol 144 (8) ◽  
pp. 3329-3337 ◽  
Author(s):  
Phillip Kezele ◽  
Michael K. Skinner

Abstract The assembly of the developmentally arrested primordial follicle and the subsequent transition of the primordial follicle to the primary follicle are critical processes in normal ovarian physiology that remain to be elucidated. Ovarian follicles do not proliferate and the primordial follicles present in the neonate represent the total number of gametes available to a female throughout her reproductive life. The primordial follicles are oocytes surrounded by less differentiated squamous granulosa cells and are derived from oocyte nests, and primary follicles are oocytes surrounded by a single layer of cuboidal granulosa cells that have initiated follicle development. Abnormalities in primordial follicle assembly, arrest, and development (i.e. primordial to primary follicle transition) can cause pathological conditions such as premature ovarian failure. In this study newborn rat ovaries were cultured for 7 d. The rate of primordial follicle assembly in vivo was identical with the rate in vitro. Interestingly, the rate of primordial follicle transition to the primary follicle was found to be 3 times greater in culture. This abnormal rate of primary follicle development in culture suggests the primordial follicle does not arrest in development as observed in vivo. To investigate this phenomena newborn rat ovaries were cultured in the presence of progesterone, estradiol or calf serum. Estradiol, progesterone, or calf serum significantly reduced the level of initial primordial to primary follicle transition. Approximately 60% of follicles make the primordial to primary follicle transition in control ovaries and about 30% in treated ovaries. Steroids and calf serum had no effect on the primordial to primary follicle transition in ovaries collected and cultured from postnatal 4-d-old rats, suggesting the effects observed are restricted to the initial wave of primordial to primary follicle transition. Interestingly, progesterone was also found to significantly reduce the rate of primordial follicle assembly. All viable oocytes assembled into primordial follicles in control ovaries and approximately 40% remained unassembled in progesterone-treated ovaries. Progesterone was also found to reduce primordial follicle assembly in vivo with 10% of the total follicles remaining unassembled in progesterone injected neonatal animals. Analysis of cellular apoptosis demonstrated that progesterone inhibited the coordinated oocyte apoptosis required for primordial follicle assembly. The hypothesis developed is that high levels of maternal and fetal steroids prevent premature primordial follicle assembly and primordial to primary follicle transition in the embryo. After birth steroid levels fall dramatically and the primordial follicles are free to assemble and initiate development. These observations suggest a novel role for steroids and the maternal-fetal endocrine unit in the control of ovarian primordial follicle assembly and early follicular development.


2019 ◽  
Vol 116 (25) ◽  
pp. 12321-12326 ◽  
Author(s):  
So Shimamoto ◽  
Yohei Nishimura ◽  
Go Nagamatsu ◽  
Norio Hamada ◽  
Haruka Kita ◽  
...  

In mammals, most immature oocytes remain dormant in the primordial follicles to ensure the longevity of female reproductive life. A precise understanding of mechanisms underlying the dormancy is important for reproductive biology and medicine. In this study, by comparing mouse oogenesis in vivo and in vitro, the latter of which bypasses the primordial follicle stage, we defined the gene-expression profile representing the dormant state of oocytes. Overexpression of constitutively active FOXO3 partially reproduced the dormant state in vitro. Based on further gene-expression analysis, we found that a hypoxic condition efficiently induced the dormant state in vitro. The effect of hypoxia was severely diminished by disruption of the Foxo3 gene and inhibition of hypoxia-inducible factors. Our findings provide insights into the importance of environmental conditions and their effectors for establishing the dormant state.


Author(s):  
Mahboobeh Amoushahi ◽  
Karin Lykke-Hartmann

Women with cancer and low ovarian reserves face serious challenges in infertility treatment. Ovarian tissue cryopreservation is currently used for such patients to preserve fertility. One major challenge is the activation of dormant ovarian follicles, which is hampered by our limited biological understanding of molecular determinants that activate dormant follicles and help maintain healthy follicles during growth. Here, we investigated the transcriptomes of oocytes isolated from dormant (primordial) and activated (primary) follicles under in vivo and in vitro conditions. We compared the biological relevance of the initial molecular markers of mature metaphase II (MII) oocytes developed in vivo or in vitro. The expression levels of genes involved in the cell cycle, signal transduction, and Wnt signaling were highly enriched in oocytes from primary follicles and MII oocytes. Interestingly, we detected strong downregulation of the expression of genes involved in mitochondrial and reactive oxygen species (ROS) production in oocytes from primordial follicles, in contrast to oocytes from primary follicles and MII oocytes. Our results showed a dynamic pattern in mitochondrial and ROS production-related genes, emphasizing their important role(s) in primordial follicle activation and oocyte maturation. The transcriptome of MII oocytes showed a major divergence from that of oocytes of primordial and primary follicles.


2021 ◽  
Vol 22 (12) ◽  
pp. 6570
Author(s):  
Yue Lv ◽  
Rui-Can Cao ◽  
Hong-Bin Liu ◽  
Xian-Wei Su ◽  
Gang Lu ◽  
...  

A better understanding of the mechanism of primordial follicle activation will help us better understand the causes of premature ovarian insufficiency (POI), and will help us identify new drugs that can be applied to the clinical treatment of infertility. In this study, single oocytes were isolated from primordial and primary follicles, and were used for gene profiling with TaqMan array cards. Bioinformatics analysis was performed on the gene expression data, and Ingenuity Pathway Analysis was used to analyze and predict drugs that affect follicle activation. An ovarian in vitro culture system was used to verify the function of the drug candidates, and we found that curcumin maintains the ovarian reserve. Long-term treatment with 100 mg/kg curcumin improved the ovarian reserve indicators of AMH, FSH, and estradiol in aging mice. Mechanistic studies show that curcumin can affect the translocation of FOXO3, thereby inhibiting the PTEN-AKT-FOXO3a pathway and protecting primordial follicles from overactivation. These results suggest that curcumin is a potential drug for the treatment of POI patients and for fertility preservation.


Development ◽  
1968 ◽  
Vol 19 (3) ◽  
pp. 407-414
Author(s):  
R. Christy Armstrong ◽  
Joel J. Elias

Abnormalities of the ocular system which appear in organ culture in Waymouth's medium with freshly added glutamine (Armstrong & Elias, 1968) resemble those caused by transitory pteryolglutamic acid (PGA or folic acid) deficiency in vivo (Armstrong & Monie, 1966). The configurations of such malformations as lens herniations, retinal diverticula, and rosette-like formations of the retina are remarkably similar in both cases. The experiments reported in this paper were undertaken in an effort to understand the mechanisms involved in the production of similar abnormalities by two very different experimental conditions: the addition of glutamine in vitro and the transitory deficiency of PGA in vivo. One series of experiments involved the effects of manipulation of the PGA and glutamine content of the culture medium on eye development in vitro. Parallel studies on PGA-deficiency in vivo were undertaken in conjunction with organ-culture experiments in order to compare the effects on abnormal eye morphogenesis.


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