WNT4 is required for normal ovarian follicle development and female fertility

Effects of Treatment with a DNA Methyltransferase Inhibitor 5-aza-dC on Sex Differentiation in Medaka (Oryzias latipes)

DNA methylation is a common epigenetic modification of DNA levels in the genome of eukaryotic cells, and an aberrant elevation of DNA methylation in gene promoter regions can inhibit gene expression. DNA methyltransferases (DNMTs) are involved in genomic DNA methylation, divided into maintenance DNA methyltransferases and de novo methylases, which are expressed to different degrees in the testis and ovaries. 5-aza-2'-deoxycytidine (5-aza-dC) is a cytidine analog with a strong methylation inhibition. In this experiment, medaka fish fries were treated with 5-aza-dC at 0 μg/L, 50 μg/L, and 100 μg/L. It was found that 100 g/L concentration of 5-aza-dC inhibited both body length and body weight of the adult fish, while 50 g/L concentration had no significant difference. In addition, paraffin section observation and gonad index statistics showed that after 100 g/L concentration of 5-aza-dC treatment, the gonad index of female fish increased significantly, but the gonad index of male fish had no significant difference. And the development of sperms and ovaries was normal without significant difference. Finally, we found that 5-aza-dC not only significantly decreased the transcription levels of dnmt1 and dnmt3bb.1, but also significantly increased the expression levels of female-related genes such as foxl2, cyp19a1 and wnt4, and significantly decreased the expression levels of male-related genes such as dmrt1, sox9a and amh. The DNA methylation patterns of foxl2 and dmrt1 genes were altered. This work provides more references for understanding the mechanism of DNA methylation affecting sex determination in fish.

Inflammation during oocyte maturation reduces developmental competence and increases apoptosis in blastocysts†

Uterine infections cause ovarian dysfunction and infertility. The bacterial endotoxin, lipopolysaccharide, accumulates in the follicular fluid of dominant follicles of cows with uterine infections. Granulosa cells produce an innate inflammatory response to lipopolysaccharide, altering the follicular microenvironment of the oocyte. We hypothesized that developmental competence and embryo quality would be reduced when oocytes are matured in an inflammatory environment. Bovine mural granulosa cells were exposed to either 1 μg/mL of lipopolysaccharide or medium alone for 24 h to produce a conditioned medium. Inflammatory responses of mural granulosa cells were confirmed by increased expression of CXCL8, IL1B, IL6, and TNF. Bovine cumulus-oocyte complexes were matured for 22 ± 1 h in a medium supplemented with either 1 μg/mL of lipopolysaccharide, 10% v/v conditioned medium of granulosa cells treated with either lipopolysaccharide (LCM) or medium alone, or no supplementation. In addition, polymyxin B (20 μg/mL) was added to the maturation medium to sequester LPS. Following maturation, cumulus-oocyte complexes were fertilized and cultured for 7.5 days with no further treatment. Oocyte maturation using lipopolysaccharide or LCM impaired development to the blastocysts stage, reduced the number of total and CDX2-negative blastomeres, and increased TUNEL-positive cells in blastocysts. Polymyxin B could rescue these effects in the lipopolysaccharide group but not in the LCM group, indicating factors produced by granulosa cells and not lipopolysaccharide alone compromised oocyte development. These findings suggest that the inflammatory milieu produced by granulosa cells in response to lipopolysaccharide impairs oocyte competence and the quality of resultant blastocyst-stage embryos.

Transcriptome and chromatin accessibility landscape of ovarian development at different egg-laying stages in taihe black-bone silky fowls

Taihe Black-Bone Silky Fowl (SF) is a famous local breed in China, known for its high nutritional and medicinal value. However, its low egg-laying rate significantly limits its economic benefits. This study aims to explore the ovarian development status, as well as the changes in the transcriptome and chromatin accessibility landscape at different egg-laying stages of SF, in order to reveal the epigenetic regulatory mechanisms underlying ovarian development in laying hens. The results showed that during peak egg-laying, serum levels of follicle stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2), and progesterone (P4) in the SF were higher than in the other laying periods. Meanwhile, the serum and ovarian matrix total antioxidant capacity (T-AOC) level decreased with increasing age, whereas the ovarian matrix malondialdehyde (MDA) level showed the opposite trend. Compared to the late laying period, several genes related to ovarian development and reproductive hormone secretion, including TDRD5, CCNO, CYP17A1, BMP15, and STAR, were upregulated during the peak egg-laying period. Additionally, we identified key transcription factors (TF) associated with different egg-laying periods. Specific TF, such as Fli1, Etv2, and AT2G15740, linked to the peak egg-laying period, play significant roles in cell and tissue development. The specific transcription factor Nr5a2, associated with the late laying period, has been shown to inhibit E2 production. Furthermore, genes related to poultry reproductive performance, such as STAR and WNT4, were found to be regulated by specific distal enhancers in open chromatin regions (OCR). In conclusion, this study elucidated the dynamic changes in the transcriptome and chromatin accessibility landscape during ovarian development in SF at different egg-laying stages and highlighted key TF, including Fli1, Etv2, and Nr5a2, as well as essential genes like STAR and WNT4 that regulate ovarian development. These findings provide valuable insights into the regulatory mechanisms influencing egg-laying performance in SF and offer new strategies for improving ovarian follicle development and egg production performance in poultry.

Dynamic m6A Modification Landscape During the Egg Laying Process of Chickens

RNA N6-methyladenosine (m6A) is one of the most common and widespread reversible epigenetic modifications of mRNAs, and m6A has been shown to play a positive role in regulating follicular development. However, the role of RNA m6A methylation in chicken ovaries and egg production has not been fully studied. In this study, we comprehensively analyzed the m6A transcriptome profiles of high- and low-yield Gushi chickens at 43 weeks of age (43 w). We found that m6A modification differed between the two groups. The m6A peak was positively correlated with the gene expression level, indicating that m6A may play an important role in regulating chicken egg production. In total, 9008 and 15,415 m6A peaks were separately identified in the two groups, including 2241 differential m6A peaks. In addition, seven candidate genes related to egg laying that were significantly enriched in the KEGG pathway related to ovary development and egg laying were identified. In summary, we constructed the first m6A modification map of ovarian tissue of Gushi chickens, and the differences in egg laying in 43 w Gushi chickens may originate from the effect of RNA methylation on the expression of egg-related genes. These findings provide new insights into the regulatory mechanisms of m6A methylation during egg production in Gushi chickens.

Prenatal Perfluorooctanoic Acid (PFOA) exposure causes reproductive toxicity by disrupting the formation of transzonal projections (TZPs) and down-regulating Wnt4/β-catenin signaling pathway in progeny

Perfluorooctanoic acid (PFOA) has been recognized as a novel persistent organic pollutant, playing a significant role in global environmental contamination. Recent evidence indicates that exposure to PFOA detrimentally affects reproductive function, notably through a progressive decline in ovarian function. However, there is a notable lack of research specifically examining its impact on the reproductive potential of female offspring. In this study, we report that prenatal exposure to PFOA impairs the competence of maturing oocytes and reduces the yield of oocytes in the progeny. Mechanistically, prenatal exposure to PFOA leads to a reduced expression of Wnt4, which subsequently impairs the integrity of the ovarian follicle basement membrane and decreases the expression of proteins related to adherent junctions in granulosa cells. This cascade of events results in a compromised reduction of transzonal projections (TZPs) within ovarian follicles, ultimately leading to mitochondrial dysfunction and diminished ATP synthesis in oocytes. This study offers comprehensive insights into the underlying mechanisms of PFOA-induced reproductive toxicity and furnishes scientific evidence to support initiatives focused on preventing and mitigating reproductive harm associated with perfluorinated compounds.

Menopause mysteries: the exosome-inflammation connection

Extracellular vesicles, or exosomes, are produced by every type of cell and contain metabolites, proteins, lipids, and nucleic acids. Their role in health and disease is to influence different aspects of cell biology and to act as intermediaries between cells. Follicular fluid exosomes or extracellular vesicles (FF-EVs) secreted by ovarian granulosa cells are critical mediators of ovary growth and maturation. The movement and proteins of these exosomes are crucial in the regulation of cellular communication and the aging of cells, a process termed inflammaging. Menopause, a natural progression in the aging of females, is often accompanied by numerous negative symptoms and health issues. It can also act as a precursor to more severe health problems, including neurological, cardiovascular, and metabolic diseases, as well as gynecological cancers. Researchers have discovered pathways that reveal the diverse effects of exosome-driven cellular communication and oocyte development in the follicular fluid. It also explores the complex functions of FF exosomal proteins in the pathologies associated with menopause.

Anti-Müllerian hormone signaling in the ovary involves stromal fibroblasts: a study in humans and mice provides novel insights into the role of ovarian stroma

STUDY QUESTION

What is the involvement of ovarian stroma in the anti-Müllerian hormone (AMH) signaling pathway and which stromal cells are involved?

SUMMARY ANSWER

Mouse and human ovaries show high expression of AMH receptor II (AMHR2) in the stromal fibroblasts surrounding the follicles and activation of the post-AMHR2 pathway by recombinant AMH was evidenced by increased phosphorylation of SMAD1,5 and 9, increased expression AMHR2 and upregulation of αSMA, suggesting fibroblast activation to initiate myofibroblast differentiation.

WHAT IS KNOWN ALREADY

AMH secreted by small growing follicles, regulates ovarian activity. It suppresses initial primordial follicle (PMF) recruitment and FSH-dependent growth. AMH signal transduction is mediated by AMHR2, activating intracellular SMAD proteins and other signaling cascades to induce target-gene expression. Although AMHR2 expression has been reported within the follicle unit, there is evidence suggesting it may be identified in the stroma as well.

STUDY DESIGN, SIZE, DURATION

Fresh murine ovaries were extracted from BALB/c mice (6 weeks old; n = 12 and 21 days old; n = 56). Frozen-thawed ovarian fragments were obtained from 10 women, aged 18-35, who had undergone ovarian tissue cryopreservation and donated frozen ovarian tissue for research.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Murine (6 weeks old) and human donor ovaries were immunostained for AMHR2 and Collagen 1α/αSMA/VCAM1, with additional vimentin staining in mice. Murine (21 days old) and human donor ovaries were used for fibroblast isolation and subsequent 7-day cultures. Prior to assessing AMH effects on isolated fibroblast culture, purity validation tests were implemented to ensure the absence of epithelial, immune, endothel, granulosa, and theca ovarian cell populations. The fibroblast culture's homogeneity was validated by RT-qPCR and western-blot assays, confirming negativity for E-cadherin, CD31, aromatase, CYP17A1, and positivity for αSMA and vimentin. Fibroblasts were then subjected to rAMH treatment in vitro (200 ng/ml) for 0-72 h, with an additional time point of 96 h for human samples, followed by RT-qPCR, western blot, and immunocytochemistry (ICC) for AMHR2 expression. AMHR2 post-receptor signaling was examined by pSMAD1,5,9 levels via western blot. Activated fibroblast marker, αSMA, was assessed via western blot and ICC.

MAIN RESULTS AND THE ROLE OF CHANCE

Immunostaining of mouse and human ovarian tissue showed that stromal cells around follicles at all developmental stages exhibit high AMHR2 expression, while granulosa cells of growing follicles show considerably lower levels. The majority of these AMHR2-positive stromal cells were identified as fibroblasts (Collagen1α in mice and human; vimentin in mice). RT-qPCR, western blot, and immunostaining were performed on cultured mouse and human fibroblasts, confirming that they consisted of a pure fibroblast population (αSMA/vimentin positive and negative for other cell-type markers). A total of 99.81% (average 28.94 ± 1.34 cells/field in mice) and 100% (average 19.20 ± 1.39 cells/field in human samples) of these fibroblasts expressed AMHR2 (ICC). rAMH treated cultured fibroblasts showed increased pSMAD1,5 and 9 levels, demonstrating the effects of AMH on its downstream signaling pathway. pSMAD1,5 and 9 expression increased, as detected by western blot: 1.92-fold in mice (48 h, P = 0.026) and 2.37-fold in human samples (48 h, P = 0.0002). In addition, rAMH treatment increased AMHR2 protein expression, as observed in ICC (human): a 2.57-fold upregulation of AMHR2 Mean Fluorescence Intensity (MFI) (96 h, P = 0.00036), and western blot, showing a 4.2-fold time-dependent increase (48 h, P = 0.026) in mice and 2.4-fold change (48 h, P = 0.0003) in human donors. Exposure to rAMH affected AMHR2 transcription upregulation, with a 6.48-fold change (72 h, P = 0.0137) in mice and a 7.87-fold change (72 h, P < 0.0001) in humans. rAMH treatment induced fibroblast activation (αSMA positive), demonstrating the dynamic effects of AMH on fibroblast behavior. αSMA expression elevation was detected in ICC with a 2.28-fold MFI increase in humans (96 h, P = 0.000067), and in western blot with a 5.12-fold increase in mice (48 h, P = 0.0345) and a 2.69-fold increase in humans (48 h, P ≤ 0.0001). Activated AMHR2-positive stained fibroblast fractions were solely located around growing follicles, in both human and mice. In addition, a small population of AMHR2-positive stained theca cells (VCAM1 positive) was observed.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

Ex vivo, fibroblast gene expression might be changed by adhesion to the tissue-culture plate. Nevertheless, cultured fibroblasts (with and without rAMH) are subjected to the same conditions. Observations or significant differences can therefore be considered reliable. In addition, the presented effect of rAMH on fibroblasts is not directly linked to the known inhibitory effect of AMH on follicle activation.

WIDER IMPLICATIONS OF THE FINDINGS

Clarifying the populations of AMH-responsive cells in the ovary provides a foundation for further investigation of the complex AMH signaling across the ovary. The composition of AMH-releasing and -responsive cells can shed light on the communication network between follicles and their environment, which may elucidate the mechanisms behind the AMH inhibitory effect on PMF activation.

STUDY FUNDING/COMPETING INTEREST(S)

This work was financially supported by grants from the Kahn Foundation. There are no competing interests in this study.

TRIAL REGISTRATION NUMBER

N/A.

Transcriptomic signatures of WNT-driven pathways and granulosa cell-oocyte interactions during primordial follicle activation

Primordial follicle activation (PFA) is a pivotal event in female reproductive biology, coordinating the transition from quiescent to growing follicles. This study employed comprehensive single-cell RNA sequencing to gain insights into the detailed regulatory mechanisms governing the synchronized dormancy and activation between granulosa cells (GCs) and oocytes with the progression of the PFA process. Wntless (Wls) conditional knockout (cKO) mice served as a unique model, suppressing the transition from pre-GCs to GCs, and disrupting somatic cell-derived WNT signaling in the ovary. Our data revealed immediate transcriptomic changes in GCs post-PFA in Wls cKO mice, leading to a divergent trajectory, while oocytes exhibited modest transcriptomic alterations. Subpopulation analysis identified the molecular pathways affected by WNT signaling on GC maturation, along with specific gene signatures linked to dormant and activated oocytes. Despite minimal evidence of continuous up-regulation of dormancy-related genes in oocytes, the loss of WNT signaling in (pre-)GCs impacted gene expression in oocytes even before PFA, subsequently influencing them globally. The infertility observed in Wls cKO mice was attributed to compromised GC-oocyte molecular crosstalk and the microenvironment for oocytes. Our study highlights the pivotal role of the WNT-signaling pathway and its molecular signature, emphasizing the importance of intercellular crosstalk between (pre-)GCs and oocytes in orchestrating folliculogenesis.

Follicle-intrinsic and spatially distinct molecular programs drive follicle rupture and luteinization during ex vivo mammalian ovulation

During ovulation, the apical wall of the preovulatory follicle breaks down to facilitate gamete release. In parallel, the residual follicle wall differentiates into a progesterone-producing corpus luteum. Disruption of ovulation, whether through contraceptive intervention or infertility, has implications for women's health. In this study, we harness the power of an ex vivo ovulation model and machine-learning guided microdissection to identify differences between the ruptured and unruptured sides of the follicle wall. We demonstrate that the unruptured side exhibits clear markers of luteinization after ovulation while the ruptured side exhibits cell death signals. RNA-sequencing of individual follicle sides reveals 2099 differentially expressed genes (DEGs) between follicle sides without ovulation induction, and 1673 DEGs 12 h after induction of ovulation. Our model validates molecular patterns consistent with known ovulation biology even though this process occurs in the absence of the ovarian stroma, vasculature, and immune cells. We further identify previously unappreciated pathways including amino acid transport and Jag-Notch signaling on the ruptured side and glycolysis, metal ion processing, and IL-11 signaling on the unruptured side of the follicle. This study yields key insights into follicle-inherent, spatially-defined pathways that underlie follicle rupture, which may further understanding of ovulation physiology and advance women's health.

Slit1 inhibits ovarian follicle development and female fertility in mice†

Previous in vitro studies have suggested that SLIT ligands could play roles in regulating ovarian granulosa cell proliferation and gene expression, as well as luteolysis. However, no in vivo study of Slit gene function has been conducted to date. Here, we investigated the potential role of Slit1 in ovarian biology using a Slit1-null mouse model. Female Slit1-null mice were found to produce larger litters than their wild-type counterparts due to increased ovulation rates. Increased ovarian weights in Slit1-null animals were found to be due to the presence of greater numbers of healthy antral follicles with similar numbers of atretic ones, suggesting both an increased rate of follicle recruitment and a decreased rate of atresia. Consistent with this, treatment of cultured granulosa cells with exogenous SLIT1 induced apoptosis in presence or absence of follicle-stimulating hormone, but had no effect on cell proliferation. Although few alterations in the messenger RNA levels of follicle-stimulating hormone-responsive genes were noted in granulosa cells of Slit1-null mice, luteinizing hormone target gene mRNA levels were greatly increased. Finally, increased phospho-AKT levels were found in granulosa cells isolated from Slit1-null mice, and SLIT1 pretreatment of cultured granulosa cells inhibited the ability of both follicle-stimulating hormone and luteinizing hormone to increase AKT phosphorylation, suggesting a mechanism whereby SLIT1 could antagonize gonadotropin signaling. These findings therefore represent the first evidence for a physiological role of a SLIT ligand in the ovary, and define Slit1 as a novel autocrine/paracrine regulator of follicle development.

Potential mechanisms and therapeutic strategies for LPS-associated female fertility decline

As a major component of the outer membrane of Gram-negative bacteria, lipopolysaccharide (LPS) can be recognized by toll-like receptors (TLRs) and induce inflammation through MyD88 or the TIR domain-containing adapter-inducing interferon-β (TRIF) pathway. Previous studies have found that LPS-associated inflammatory/immune challenges were associated with ovarian dysfunction and reduced female fertility. However, the etiology and pathogenesis of female fertility decline associated with LPS are currently complex and multifaceted. In this review, PubMed was used to search for references on LPS and fertility decline so as to elucidate the potential mechanisms of LPS-associated female fertility decline and summarize therapeutic strategies that may improve LPS-associated fertility decline.

Role of secreted frizzled-related protein 5 in granulosa cells of hu sheep ovaries

The objective of this study was to examine the expression patterns of secreted frizzled-related protein 5 (SFRP5) in the ovaries of Hu sheep and to explore the key downstream factors of SFRP5 in sheep granulosa cells (GCs) using RNA-seq. In the present study, SFRP5 was widely expressed in the ovary and localized to GCs and oocytes during various stages of follicular development. In addition, the expression of SFRP5 increased with follicular diameter. In contrast to the negative control, SFRP5 knockdown promoted the EdU-positive cell rate with an increase in PCNA mRNA and protein levels, whereas SFRP5 overexpression had the opposite effect. In addition, the cell cycle was propelled from the G0/G1 phase to the S phase with the upregulation of CCNB1, CCND1, CDK1, and CDK4 after SFRP5 knockdown. Moreover, SFRP5 overexpression enhanced the apoptosis of GCs with increased Caspase3 protein levels. Following SFRP5 knockdown, differentially expressed genes were mainly enriched in the PI3K/AKT, MAPK, Wnt, and Hippo signaling pathways, and several related candidate genes such as MMP1, MMP3, SFRP4, INHA, TGFA, and CASP3 were screened. In general, this study enhances our understanding of the expression of SFRP5 in the GCs of Hu sheep, along with its functions in follicular development.

β-Catenin regulates ovarian granulosa cell cycle and proliferation in laying hens by interacting with TCF4

Ovarian follicle development depends on the proliferation and differentiation of granulosa cells and is a complex biological process. The Wnt/β-catenin signaling pathway can regulate ovarian follicle development, and β-catenin, encoded by catenin beta 1 (CTNNB1), is the core component of this pathway. Although several studies of the mechanisms by which the Wnt/β-catenin pathway regulates cell proliferation in humans and mammals have reported, it remains unclear how β-catenin functions in poultry. To investigate the function of β-catenin in laying hens' follicle development, we evaluated the effect of CTNNB1 on cell cycle, proliferation, and apoptosis in ovarian granulosa cells (GCs) isolated from laying hens. We demonstrated that CTNNB1 significantly affected the expression of cyclin D1 (CCND1) and v-myc avian myelocytomatosis viral oncogene homolog (c-Myc) (P < 0.01 and P < 0.05), key genes related to cell cycle and proliferation, to promote cell cycle progression from G1 to S phase, and thus accelerate granulosa cell proliferation. CTNNB1 did not however affect apoptosis or the expression of related genes baculoviral IAP repeat containing 5 (BIRC5) and BCL2 apoptosis regulator (Bcl-2). Overexpression of transcription factor 7-like 2 (TCF4) resulted in increased expression of CCND1, accelerated cell cycle progression, and granulosa cell proliferation. Direct physical interaction between β-catenin and TCF4 was demonstrated by immunofluorescence and coimmunoprecipitation. The proliferation of granulosa cells was inhibited by silencing CCND1; overexpression of TCF4 in CCND1-silenced cells restored their proliferation rate to normal levels. These results indicate that the interaction of TCF4 and β-catenin promotes CCND1 expression which in turn accelerates the cell cycle process of laying hen hierarchical follicular granulosa cells.

Analysis of cell-cell interaction between mural granulosa cells and cumulus granulosa cells during ovulation using single-cell RNA sequencing data of mouse ovary

Purpose

We investigated the interactions between mural granulosa cells (MGCs) and cumulus granulosa cells (CGCs) during ovulation after the LH surge.

Methods

We performed clustering, pseudotime, and interactome analyses utilizing reported single-cell RNA sequencing data of mouse ovary at 6 h after eCG-hCG injection.

Results

Clustering analysis classified granulosa cells into two distinct populations, MGCs and CGCs. Pseudotime analysis divided granulosa cells into before and after the LH surge, and further divided them into two branches, the ovulatory MGCs and the ovulatory CGCs. Interactome analysis was performed to identify the interactions between MGCs and CGCs. Twenty-six interactions were acting from CGCs toward MGCs, involving ovulation and steroidogenesis. Thirty-six interactions were acting from MGCs toward CGCs, involving hyaluronan synthesis. There were 25 bidirectional interactions, involving the EGFR pathway. In addition, we found three novel interactions: Ephrins-Ephs pathway and Wnt-Lrp6 pathway from CGCs to MGCs, associated with steroidogenesis and lipid transport, respectively, and TGF-β-TGFBR1 pathway from MGCs to CGCs, associated with hyaluronan synthesis.

Conclusions

MGCs and CGCs interact with each other in the preovulatory follicle after the LH surge, and their interactions have roles in corpus luteum formation, oocyte maturation, and follicle rupture.

Expression and regulation of Noggin4 gene in chicken ovarian follicles and its role in the proliferation and differentiation of granulosa cells

As a member of Noggin family, Noggin4 is reported to play an important role in the formation of head structure during the embryo development of Xenopus laevis and chicken. We previously detected an increase of Noggin4 transcript in the granulosa cells of chicken hierarchal follicles (Post-GCs) compared to pre-hierarchal follicles (Pre-GCs) by ONT transcriptome sequencing. To further clarify the role of Noggin4 in chicken follicle selection, in this study, we investigated its expression, regulation and function in follicles and granulosa cells. The mRNA expression of chicken Noggin4 exhibited dynamic changes during follicle development. It was significantly higher in the small yellow follicles than in the small white, F6, F5 and F4 follicles, and also increased in Post-GCs than in Pre-GCs. The Noggin4 mRNA could be stimulated by follicle stimulating hormone (FSH) and bone morphogenetic protein 4 (BMP4) in both Pre-GCs and Post-GCs. However, the estrogen and progesterone could exert opposing transcriptional regulations on Noggin 4 mRNA in both Pre- and Post-GCs. In chicken Post-GCs, knockdown of Noggin4 by siRNA reduced the mRNA expression of steroidogenic acute regulatory protein (STAR), cytochrome P450 family 11 subfamily A member 1 (CYP11A1), but increased that of Wnt family member 4 (Wnt4), while overexpression of Noggin4 significantly decreased the mRNA expression of Wnt4 but had no marked effects on that of STAR and CYP11A1. Moreover, Noggin4 significantly decreased the mRNA expression of BMP4 in both Pre-GCs and Post-GCs. Overexpression of Noggin4 inhibited the proliferation of both Pre-GCs and Post-GCs. These data collectively suggest an important role of Noggin4 in chicken follicle selection, especially on the proliferation of granulosa cells.

Potential Therapeutic Options for Premature Ovarian Insufficiency: Experimental and Clinical Evidence

Premature ovarian insufficiency (POI) is a condition in which a woman experiences premature decline in ovarian function before the age of 40 years, manifested by menstrual disorders, decreased fertility, and possibly postmenopausal symptoms such as insomnia, hot flashes, and osteoporosis, and is one of the predominant clinical syndromes leading to female infertility. Genetic, immunologic, iatrogenic and other factors, alone or in combination, have been reported to trigger POI, yet the etiology remains unknown in most cases. The main methods currently used clinically to ameliorate menopausal symptoms due to hypoestrogenemia in POI patients are hormone replacement therapy, while the primary methods available to address infertility in POI patients are oocyte donation and cryopreservation techniques, both of which have limitations to some degree. In recent years, researchers have continued to explore more efficient and safe therapies, and have achieved impressive results in preclinical trials. In this article, we will mainly review the three most popular therapies and their related signaling pathways published in the past ten years, with the aim of providing ideas for clinical applications.

WNT4 Gene and Protein Expression in Endometrial Cancer and Its Significance

BACKGROUND

The inappropriate action of WNT4 and estrogens affects uterine homeostasis and function, and may lead to endometrial cancer (EC).

OBJECTIVE

The aim was to evaluate the alterations of WNT4 gene expression and WNT4 protein immunoreactivity (Ir) in EC, considering tumor characteristics, the clinicopathological association and estrogen dependence.

METHODS

WNT4 mRNA levels were compared between benign (control) endometrium (n = 8) and endometroid EC (EEC) and non-endometroid EC (non-EEC) samples (n = 28) using the real-time PCR technique. The WNT4-Ir and ERα-Ir were evaluated by immunohistochemistry (IHC). WNT4 mRNA gene and WNT4-Ir were correlated with clinicopathological and blood morphological parameters. Overall survival (OS) was assessed. The bioanalysis was utilized to study WNT4 expression in large patient cohort (n = 549).

RESULTS

WNT4 gene expression was decreased in EC samples (specifically in EEC but not in non-EEC) compared to the control. The WNT4 gene expression was also decreased in EC samples categorized by the tumor characteristics. There was no statistical difference in WNT4-Ir or ERα-Ir between the control and EC. There was no correlation between OS and WNT4 gene expression and WNT4-Ir. Bioanalysis showed that WNT4 and ESR1 gene expression alterations tended to be mutually exclusive. An alteration in WNT4 expression was found in different histological tumor types in a large group of EC patients.

CONCLUSIONS

There is a great need to evaluate the molecular background of EC. Our study suggests that the WNT4 gene has the potential to be a marker of functional estrogen signaling in EEC.

Subacute exposure to Roundup® changes steroidogenesis and gene expression of the glutathione-glutaredoxin system in rat ovaries: Implications for ovarian toxicity of this glyphosate-based herbicide

Studies have indicated that glyphosate induces endocrine disruption and may adversely affect the male reproductive system. However, evidence of its effects on ovarian function is poorly understood so far, making further studies necessary on the mechanisms of the glyphosate toxicity in the female reproductive system. The aim of this work was to evaluate the effect of a subacute exposure (28 days) to the glyphosate-based formulation Roundup® (1.05, 10.5 and 105 μg/kg b.w. of glyphosate) on steroidogenesis, oxidative stress, systems involved in cell redox control and histopathological parameters in rat ovaries. Hence we quantify plasma estradiol and progesterone by chemiluminescence; non-protein thiol levels, TBARS, superoxide dismutase and catalase activity by spectrophotometry; gene expression of steroidogenic enzymes and redox systems by real-time PCR; and ovarian follicles by optical microscopy. Our results demonstrated that oral exposure increased progesterone levels and the mRNA expression of 3β-hydroxysteroid dehydrogenase. Histopathological analysis revealed a decrease in the number of primary follicles and an increase in the number of corpus luteum in rats exposed to Roundup®. An imbalance of the oxidative status was also evidenced by decreasing the catalase activity at all groups exposed to the herbicide. Increased lipid peroxidation and gene expression of glutarredoxin and decreased of glutathione reductase were also observed. Our results indicate that Roundup® causes endocrine disruption of hormones related to female fertility and reproduction and changes the oxidative status by altering antioxidant activity, inducing lipid peroxidation, as well as changing the gene expression of the glutathione-glutarredoxin system in rat ovaries.

Iron intake in relation to ovarian reserve among women seeking infertility treatment

STUDY QUESTION

Is there an association between iron intake and ovarian reserve among women seeking fertility care?

SUMMARY ANSWER

Supplemental iron intake above 45 mg/day is associated with lower ovarian reserve among women seeking fertility care.

WHAT IS KNOWN ALREADY

Although the literature regarding iron intake in relation to ovarian reserve is scant and inconsistent, some evidence suggests that iron may have gonadotoxic effects.

STUDY DESIGN, SIZE, DURATION

This observational study included 582 female participants attending the Massachusetts General Hospital Fertility Center (2007-2019) enrolled in the Environment and Reproductive Health (EARTH) Study.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Iron intake was estimated using a validated food frequency questionnaire. Markers of ovarian reserve included antral follicle count (AFC) (assessed via transvaginal ultrasound) and Day 3 FSH, both obtained during the course of an infertility evaluation.

MAIN RESULTS AND THE ROLE OF CHANCE

Participants had a median age of 35 years and median total iron intake of 29 mg/day. Total iron intake was inversely related to AFC and this association was driven by intake of supplemental iron. Compared to women with a supplemental iron intake of ≤20 mg/day, women consuming 45-64 mg/day of supplemental iron had a 17% (-35%, 0.3%) lower AFC and women consuming ≥65 mg/day of supplemental iron had a 32% (-54%, -11%) lower AFC after adjusting for potential confounders (P, linear trend = 0.003). Similarly, in a multivariable-adjusted analysis, Day 3 FSH levels were 0.9 (0.5, 1.3) IU/ml higher among women with a supplemental iron intake of ≥65 mg/day when compared to women with a supplemental iron intake of ≤20 mg/day (P, linear trend = 0.02).

LIMITATIONS, REASONS FOR CAUTION

Iron intake was estimated using a method that relies on self-report and we had no biomarkers of iron status in our participants; only 36 women consumed ≥45 mg/day of supplemental iron.

WIDER IMPLICATIONS OF THE FINDINGS

Since all study participants were seeking fertility treatment, our findings may not apply to women in the general population. Although our findings are consistent with studies of women with iron overload, given the paucity of literature on this topic, it is essential that this question is revisited in studies designed to better understand the dose-response relation of this association across the entire distribution of ovarian reserve and the risk-benefit balance of pre-conceptional iron supplementation given its many positive effects on pregnancy outcomes.

STUDY FUNDING/COMPETING INTEREST(S)

The project was funded by Grants R01ES022955, R01ES033651, R01ES009718, P30ES000002, and P30DK046200 from the National Institutes of Health. N.J.-C. was supported by a Fulbright Scholarship. N.J.-C., M.M., L.M.-A., E.O.-P., S.W., I.S., and J.E.C. declare no conflict of interest related to the work in the manuscript. R.H. has received grants from the National Institute of Environmental Health Sciences.

TRIAL REGISTRATION NUMBER

N/A.

SOX7 deficiency causes ventricular septal defects through its effects on endocardial-to-mesenchymal transition and the expression of Wnt4 and Bmp2

SOX7 is a transcription factor-encoding gene located in a region on chromosome 8p23.1 that is recurrently deleted in individuals with ventricular septal defects (VSDs). We have previously shown that Sox7-/- embryos die of heart failure around E11.5. Here, we demonstrate that these embryos have hypocellular endocardial cushions with severely reduced numbers of mesenchymal cells. Ablation of Sox7 in the endocardium also resulted in hypocellular endocardial cushions, and we observed VSDs in rare E15.5 Sox7flox/-;Tie2-Cre and Sox7flox/flox;Tie2-Cre embryos that survived to E15.5. In atrioventricular explant studies, we showed that SOX7 deficiency leads to a severe reduction in endocardial-to-mesenchymal transition (EndMT). RNA-seq studies performed on E9.5 Sox7-/- heart tubes revealed severely reduced Wnt4 transcript levels. Wnt4 is expressed in the endocardium and promotes EndMT by acting in a paracrine manner to increase the expression of Bmp2 in the myocardium. Both WNT4 and BMP2 have been previously implicated in the development of VSDs in individuals with 46,XX sex reversal with dysgenesis of kidney, adrenals and lungs (SERKAL) syndrome and in individuals with short stature, facial dysmorphism and skeletal anomalies with or without cardiac anomalies 1 (SSFSC1) syndrome, respectively. We now show that Sox7 and Wnt4 interact genetically in the development of VSDs through their additive effects on endocardial cushion development with Sox7+/-;Wnt4+/- double heterozygous embryos having hypocellular endocardial cushions and perimembranous and muscular VSDs not seen in their Sox7+/- and Wnt4+/- littermates. These results provide additional evidence that SOX7, WNT4 and BMP2 function in the same pathway during mammalian septal development and that their deficiency can contribute to the development of VSDs in humans.

SWI/SNF chromatin remodeling subunit Smarca4/BRG1 is essential for female fertility†

Mammalian folliculogenesis is a complex process that involves the regulation of chromatin structure for gene expression and oocyte meiotic resumption. The SWI/SNF complex is a chromatin remodeler using either Brahma-regulated gene 1 (BRG1) or BRM (encoded by Smarca4 and Smarca2, respectively) as its catalytic subunit. SMARCA4 loss of expression is associated with a rare type of ovarian cancer; however, its function during folliculogenesis remains poorly understood. In this study, we describe the phenotype of BRG1 mutant mice to better understand its role in female fertility. Although no tumor emerged from BRG1 mutant mice, conditional depletion of Brg1 in the granulosa cells (GCs) of Brg1fl/fl;Amhr2-Cre mice caused sterility, whereas conditional depletion of Brg1 in the oocytes of Brg1fl/fl;Gdf9-Cre mice resulted in subfertility. Recovery of cumulus-oocyte complexes after natural mating or superovulation showed no significant difference in the Brg1fl/fl;Amhr2-Cre mutant mice and significantly fewer oocytes in the Brg1fl/fl;Gdf9-Cre mutant mice compared with controls, which may account for the subfertility. Interestingly, the evaluation of oocyte developmental competence by in vitro culture of retrieved two-cell embryos indicated that oocytes originating from the Brg1fl/fl;Amhr2-Cre mice did not reach the blastocyst stage and had higher rates of mitotic defects, including micronuclei. Together, these results indicate that BRG1 plays an important role in female fertility by regulating granulosa and oocyte functions during follicle growth and is needed for the acquisition of oocyte developmental competence.

Loss of WNT4 in the gubernaculum causes unilateral cryptorchidism and fertility defects

Undescended testis (UDT) affects 6% of male births. Despite surgical correction, some men with unilateral UDT may experience infertility with the contralateral descended testis (CDT) showing no A-dark spermatogonia. To improve our understanding of the etiology of infertility in UDT, we generated a novel murine model of left unilateral UDT. Gubernaculum-specific Wnt4 knockout (KO) mice (Wnt4-cKO) were generated using retinoic acid receptor β2-cre mice and were found to have a smaller left-unilateral UDT. Wnt4-cKO mice with abdominal UDT had an increase in serum follicle-stimulating hormone and luteinizing hormone and an absence of germ cells in the undescended testicle. Wnt4-cKO mice with inguinal UDT had normal hormonal profiles, and 50% of these mice had no sperm in the left epididymis. Wnt4-cKO mice had fertility defects and produced 52% fewer litters and 78% fewer pups than control mice. Wnt4-cKO testes demonstrated increased expression of estrogen receptor α and SOX9, upregulation of female gonadal genes, and a decrease in male gonadal genes in both CDT and UDT. Several WNT4 variants were identified in boys with UDT. The presence of UDT and fertility defects in Wnt4-cKO mice highlights the crucial role of WNT4 in testicular development.

Low-Grade Ovarian Stromal Tumors with Genetic Alterations of the Wnt/β-Catenin Pathway That Is Crucial in Ovarian Follicle Development and Regulation

The Wnt signaling pathway is important in the normal development and regulation of ovarian follicles throughout the lifecycle of females. Dysregulation of the Wnt signaling pathway, genetically or epigenetically, with subsequent activation of β-catenin has been implicated in tumorigenesis of a spectrum of ovarian neoplasms, from benign to malignant. We review the recent findings of the Wnt signaling pathway involved in regulating normal physiologic processes of the ovarian follicle cycle. We also review the β-catenin mutations in a family of low-grade ovarian stromal tumors, focusing on characterizing their shared morphological features and the utility of immunohistochemistry of β-catenin in facilitating the accurate diagnosis of these ovarian stromal tumors. The Wnt signaling pathway is one of the most critical mechanisms in regulating cell proliferation, differentiation, and morphogenesis. The Wnt signaling pathway comprises a diverse group of glycoproteins that serve as ligands and bind to transmembrane Frizzled family receptors. The ligand-receptor interactions activate the pathway and govern the downstream signaling cascades, ultimately affecting the transcriptional control of the cellular cytoskeleton, organelle dynamics, epithelial-mesenchymal interaction, and tissue remodeling in the ovary. Wnt signaling consists of two major pathways: a canonical pathway that is β-catenin-dependent and a non-canonical Wnt pathway that is β-catenin-independent. Canonical Wnt signaling is governed by the interaction of β-catenin with other molecules to regulate cellular decisions related to proliferation and differentiation. Recent studies have demonstrated that the Wnt signaling pathway plays important roles in the development and regulation of ovarian folliculogenesis and oogenesis.

A Novel Single-Nucleotide Polymorphism in WNT4 Promoter Affects Its Transcription and Response to FSH in Chicken Follicles

The signaling pathway of the wingless-type mouse mammary tumor virus integration site (Wnt) plays an important role in ovarian and follicular development. In our previous study, WNT4 was shown to be involved in the selection and development of chicken follicles by upregulating the expression of follicle-stimulating hormone receptors (FSHR), stimulating the proliferation of follicular granulosa cells, and increasing the secretion of steroidal hormones. FSH also stimulates the expression of WNT4. To further explore the molecular mechanism by which FSH upregulates WNT4 and characterize the cis-elements regulating WNT4 transcription, in this study, we determined the critical regulatory regions affecting chicken WNT4 transcription. We then identified a single-nucleotide polymorphism (SNP) in this region, and finally analyzed the associations of the SNP with chicken production traits. The results showed that the 5′ regulatory region from −3354 to −2689 of WNT4 had the strongest activity and greatest response to FSH stimulation, and we identified one SNP site in this segment, −3015 (G > C), as affecting the binding of NFAT5 (nuclear factor of activated T cells 5) and respones to FSH stimulation. When G was replaced with C at this site, it eliminated the NFAT5 binding. The mRNA level of WNT4 in small yellow follicles of chickens with genotype GG was significantly higher than that of the other two genotypes. Moreover, this locus was found to be significantly associated with comb length in hens. Individuals with the genotype CC had longer combs. Collectively, these data suggested that SNP−3015 (G > C) is involved in the regulation of WNT4 gene expression by responding FSH and affecting the binding of NFAT5 and that it is associated with chicken comb length. The current results provide a reference for further revealing the response mechanism between WNT and FSH.

Early Gonadal Development and Sex Determination in Mammal

Sex determination is crucial for the transmission of genetic information through generations. In mammal, this process is primarily regulated by an antagonistic network of sex-related genes beginning in embryonic development and continuing throughout life. Nonetheless, abnormal expression of these sex-related genes will lead to reproductive organ and germline abnormalities, resulting in disorders of sex development (DSD) and infertility. On the other hand, it is possible to predetermine the sex of animal offspring by artificially regulating sex-related gene expression, a recent research hotspot. In this paper, we reviewed recent research that has improved our understanding of the mechanisms underlying the development of the gonad and primordial germ cells (PGCs), progenitors of the germline, to provide new directions for the treatment of DSD and infertility, both of which involve manipulating the sex ratio of livestock offspring.

The Hippo Pathway Effectors YAP and TAZ Regulate LH Release by Pituitary Gonadotrope Cells in Mice

The Hippo transcriptional coactivators YAP and TAZ exert critical roles in morphogenesis, organ size determination and tumorigenesis in many tissues. Although Hippo kinase cascade activity was recently reported in the anterior pituitary gland in mice, the role of the Hippo effectors in regulating gonadotropin production remains unknown. The objective of this study was therefore to characterize the roles of YAP and TAZ in gonadotropin synthesis and secretion. Using a conditional gene targeting approach (cKO), we found that gonadotrope-specific inactivation of Yap and Taz resulted in increased circulating levels of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) in adult male mice, along with increased testosterone levels and testis weight. Female cKO mice had increased circulating LH (but not FSH) levels, which were associated with a hyperfertility phenotype characterized by higher ovulation rates and larger litter sizes. Unexpectedly, the loss of YAP/TAZ did not appear to affect the expression of gonadotropin subunit genes, yet both basal and GnRH-induced LH secretion were increased in cultured pituitary cells from cKO mice. Likewise, pharmacologic inhibition of YAP binding to the TEAD family of transcription factors increased both basal and GnRH-induced LH secretion in LβT2 gonadotrope-like cells in vitro without affecting Lhb expression. Conversely, mRNA levels of ChgA and SgII, which encode key secretory granule cargo proteins, were decreased following pharmacologic inhibition of YAP/TAZ, suggesting a mechanism whereby YAP/TAZ regulate the LH secretion machinery in gonadotrope cells. Together, these findings represent the first evidence that Hippo signaling may play a role in regulating pituitary LH secretion.

Evaluating the Expression of Wnt Pathway Related Genes in Mouse Vitrified Preantral Follicles: An Experimental Study

Background

Wnt signaling pathway plays critical role in ovarian follicle development. Therefore, the aim of this study was to evaluate the effects of vitrification on the expression of Wnt pathway related genes in preantral follicles (PFs).

Methods

Isolated PFs (n=982) of 14-16 day old female mice (n=45: 15 for each group) were divided into fresh (n=265), toxicity (n=272), and vitrified (n=265). The mRNA levels of Wnt2, Wnt4, Lrp5 and Fzd3 were evaluated by real-time PCR on the 2nd and 6th days of culture period. One-way ANOVA was conducted to analyze the data. Post hoc Tukey's HSD was used for multiple comparisons and p-value less than 0.05 was considered statistically significant.

Results

The developmental parameters of fresh PFs were significantly higher than those of vitrified (p<0.001). There were no differences between fresh and vitrified PFs on the 2nd day of culture (p<0.001). Wnt4 expression levels decreased significantly in vitrified groups compared with fresh ones (p<0.001). Fzd3 and Lrp expression levels increased significantly in vitrified groups compared with those in the fresh group on the 2nd day (p<0.001). On the 6th day of culture period, the expression levels of Wnt2 and Fzd3 increased significantly in vitrified group compared to those of fresh group (p<0.001). Moreover, the expression levels of Wnt4 and Lrp increased significantly in toxicity groups compared to those of the control group (p<0.001).

Conclusion

Vitrification increase the expression levels of Wnt2, Lrp and Fzd3 genes of PFs during in vitro culture.

Protein kinase A drives paracrine crisis and WNT4-dependent testis tumor in Carney complex

Large-cell calcifying Sertoli cell tumors (LCCSCTs) are among the most frequent lesions occurring in male Carney complex (CNC) patients. Although they constitute a key diagnostic criterion for this rare multiple neoplasia syndrome resulting from inactivating mutations of the tumor suppressor PRKAR1A, leading to unrepressed PKA activity, LCCSCT pathogenesis and origin remain elusive. Mouse models targeting Prkar1a inactivation in all somatic populations or separately in each cell type were generated to decipher the molecular and paracrine networks involved in the induction of CNC testis lesions. We demonstrate that the Prkar1a mutation was required in both stromal and Sertoli cells for the occurrence of LCCSCTs. Integrative analyses comparing transcriptomic, immunohistological data and phenotype of mutant mouse combinations led to the understanding of human LCCSCT pathogenesis and demonstrated PKA-induced paracrine molecular circuits in which the aberrant WNT4 signal production is a limiting step in shaping intratubular lesions and tumor expansion both in a mouse model and in human CNC testes.

Integrated analyses of miRNA-mRNA expression profiles of ovaries reveal the crucial interaction networks that regulate the prolificacy of goats in the follicular phase

BACKGROUND

Litter size is an important index of mammalian prolificacy and is determined by the ovulation rate. The ovary is a crucial organ for mammalian reproduction and is associated with follicular development, maturation and ovulation. However, prolificacy is influenced by multiple factors, and its molecular regulation in the follicular phase remains unclear.

METHODS

Ten female goats with no significant differences in age and weight were randomly selected and divided into either the high-yielding group (n = 5, HF) or the low-yielding group (n = 5, LF). Ovarian tissues were collected from goats in the follicular phase and used to construct mRNA and miRNA sequencing libraries to analyze transcriptomic variation between high- and low-yield Yunshang black goats. Furthermore, integrated analysis of the differentially expressed (DE) miRNA-mRNA pairs was performed based on their correlation. The STRING database was used to construct a PPI network of the DEGs. RT-qPCR was used to validate the results of the predicted miRNA-mRNA pairs. Luciferase analysis and CCK-8 assay were used to detect the function of the miRNA-mRNA pairs and the proliferation of goat granulosa cells (GCs).

RESULTS

A total of 43,779 known transcripts, 23,067 novel transcripts, 424 known miRNAs and 656 novel miRNAs were identified by RNA-seq in the ovaries from both groups. Through correlation analysis of the miRNA and mRNA expression profiles, 263 negatively correlated miRNA-mRNA pairs were identified in the LF vs. HF comparison. Annotation analysis of the DE miRNA-mRNA pairs identified targets related to biological processes such as "estrogen receptor binding (GO:0030331)", "oogenesis (GO:0048477)", "ovulation cycle process (GO:0022602)" and "ovarian follicle development (GO:0001541)". Subsequently, five KEGG pathways (oocyte meiosis, progesterone-mediated oocyte maturation, GnRH signaling pathway, Notch signaling pathway and TGF-β signaling pathway) were identified in the interaction network related to follicular development, and a PPI network was also constructed. In the network, we found that CDK12, FAM91A1, PGS1, SERTM1, SPAG5, SYNE1, TMEM14A, WNT4, and CAMK2G were the key nodes, all of which were targets of the DE miRNAs. The PPI analysis showed that there was a clear interaction among the CAMK2G, SERTM1, TMEM14A, CDK12, SYNE1 and WNT4 genes. In addition, dual luciferase reporter and CCK-8 assays confirmed that miR-1271-3p suppressed the proliferation of GCs by inhibiting the expression of TXLNA.

CONCLUSIONS

These results increase the understanding of the molecular mechanisms underlying goat prolificacy. These results also provide a basis for studying interactions between genes and miRNAs, as well as the functions of the pathways in ovarian tissues involved in goat prolificacy in the follicular phase.

The Signaling Pathways Involved in Ovarian Follicle Development

The follicle is the functional unit of the ovary, which is composed of three types of cells: oocytes, granulosa cells, and theca cells. Ovarian follicle development and the subsequent ovulation process are coordinated by highly complex interplay between endocrine, paracrine, and autocrine signals, which coordinate steroidogenesis and gametogenesis. Follicle development is regulated mainly by three organs, the hypothalamus, anterior pituitary, and gonad, which make up the hypothalamic-pituitary-gonadal axis. Steroid hormones and their receptors play pivotal roles in follicle development and participate in a series of classical signaling pathways. In this review, we summarize and compare the role of classical signaling pathways, such as the WNT, insulin, Notch, and Hedgehog pathways, in ovarian follicle development and the underlying regulatory mechanism. We have also found that these four signaling pathways all interact with FOXO3, a transcription factor that is widely known to be under control of the PI3K/AKT signaling pathway and has been implicated as a major signaling pathway in the regulation of dormancy and initial follicular activation in the ovary. Although some of these interactions with FOXO3 have not been verified in ovarian follicle cells, there is a high possibility that FOXO3 plays a core role in follicular development and is regulated by classical signaling pathways. In this review, we present these signaling pathways from a comprehensive perspective to obtain a better understanding of the follicular development process.

Wingless-type mouse mammary tumor virus integration site regulation of bovine theca cells

Ovarian paracrine mediation by components of the wingless-type mouse mammary tumor virus integration site ligands (WNT1 to 11) and their receptors, frizzled family members (FZD1 to 10), has been proposed. Secreted truncated forms of FZD proteins (e.g., secreted frizzled-related protein 4 [SFRP4]) block the action of WNT ligands. Dickkopf-1 (DKK1) is another WNT antagonist, and R-spondin-1 (RSPO1) is one of a group of four secreted proteins that enhance WNT/β-catenin signaling. Our hypothesis was that granulosa cells signal theca cells (TCs) via SFRP4, DKK1, RSPO1, and WNT secretion to regulate TC differentiation and proliferation. Therefore, in vitro experiments were conducted to study the effects of WNT family member 3A (WNT3A), WNT5A, RSPO1, DKK1, insulin-like growth factor 1 (IGF1), bone morphogenetic protein 7 (BMP7), Indian hedgehog (IHH), and fibroblast growth factor 9 (FGF9) on bovine TC proliferation and steroidogenesis. TCs of large (8 to 20 mm) and small (3 to 6 mm) follicles were collected from bovine ovaries; TC monolayers were established in vitro and treated with various doses of recombinant human WNT3A, WNT5A, RSPO1, DKK1, IGF1, FGF9, BMP7, IHH, and/or ovine luteinizing hormone (LH) in serum-free medium for 48 h. In experiment 1, using LH-treated TC, IGF1, IHH, and WNT3A increased (P < 0.05) cell numbers and androstenedione production, whereas WNT3A and BMP7 inhibited (P < 0.05) progesterone production. In experiment 2, FGF9 blocked (P < 0.05) the WNT3A-induced increase in androstenedione production in LH plus IGF1-treated TC. In experiment 3, RSPO1 further increased (P < 0.05) LH plus IGF1-induced progesterone and androstenedione production. In experiment 4, SFRP4 and DKK1 alone had no significant effect on TC proliferation or progesterone production of large-follicle TC but both blocked the inhibitory effect of WNT5A on androstenedione production. In contrast, DKK1 alone inhibited (P < 0.05) small-follicle TC androstenedione production whereas SFRP4 was without effect. We conclude that the ovarian TC WNT system is functional in cattle, with WNT3A increasing proliferation and androstenedione production of TC.

Exogenous insulin-like growth factor 1 accelerates growth and maturation of follicles in human cortical xenografts and increases ovarian output in mice

OBJECTIVE

To measure the influence of exogenous insulin-like growth factor 1 (IGF1) on follicle growth and maturation in human ovarian cortical xenografts.

DESIGN

Xenotransplantation model.

SETTING

University-based research laboratory.

PATIENTS/ANIMALS

Ovarian tissue was donated with consent and institutional review board approval by brain-dead organ donors or patients undergoing ovarian tissue cryopreservation for fertility preservation. Cortical fragments were transplanted into immunocompromised mice.

INTERVENTIONS

Cryopreserved ovarian cortical fragments from four women (aged 19, 25, 33, and 46 years) were transplanted into the gluteus muscle of immunocompromised mice in a fibrin matrix containing endothelial cells that were transduced with lentiviral particles encoding secreted IGF1. Xenografts were recovered after 3, 8, and 14 weeks. In addition, C57/Bl6 mice underwent intraovarian injection of saline or recombinant IGF1 (60 μg), followed by superovulation, analysis of ethynyl-deoxyuridine incorporation, and ribonucleic acid sequencing of the whole ovaries.

MAIN OUTCOME MEASURES

For xenografts: follicle count and distribution; antral follicle count; and corpora lutea/albicans count. For mice: follicle count and distribution; oocyte yield, ethynyl-deoxyuridine incorporation (granulosa cell proliferation); and ovarian transcriptomic signature.

RESULTS

At 3 weeks, xenografts in the IGF1 condition revealed a decreased percentage of primary follicles and increased percentage of secondary follicles that were concentrated in the preantral subtype; at 8 weeks, an increase in secondary follicles was concentrated in the simple subtype; after 14 weeks, primordial follicles were reduced, and while the number of advanced follicles did not power the experiment to demonstrate significance, antral follicles reduced and corpora lutea increased. Supporting experiments in mice revealed an increase in normal oocytes following intraovarian injection of recombinant IGF1 (60 μg) as well as increased proliferative index among follicles of secondary and preantral stages. Ribonucleic acid sequencing analysis of the whole ovaries following injection of recombinant IGF1 (25 μg) revealed an acute (24 hours) upregulation of transcripts related to steroidogenesis and luteinization.

CONCLUSIONS

Exogenous IGF1 advances the pace of growth among primordial, primary, and secondary stage follicles but results in near absence of antral stage follicles in long-term (14 weeks) xenografts. In mice, acute administration of IGF1 promotes follicle advance and increased oocyte yield. The results suggest that while superphysiological IGF1 alone advances the pace of growth among early/preantral follicles, a sustained and/or later-stage influence undermines antral follicle growth/survival or promotes premature luteinization. These findings provide a temporal framework for interpreting follicle growth/mobilization and may be useful in understanding the clinical application of human growth hormone in the context of assisted reproduction.

A kaleidoscopic view of ovarian genes associated with premature ovarian insufficiency and senescence

Ovarian infertility and subfertility presenting with premature ovarian insufficiency (POI) and diminished ovarian reserve are major issues facing the developed world due to the trend of delaying childbirth. Ovarian senescence and POI represent a continuum of physiological/pathophysiological changes in ovarian follicle functions. Based on advances in whole exome sequencing, evaluation of gene copy variants, together with family-based and genome-wide association studies, we discussed genes responsible for POI and ovarian senescence. We used a gene-centric approach to sort out literature deposited in the Ovarian Kaleidoscope database (http://okdb.appliedbioinfo.net) by sub-categorizing candidate genes as ligand-receptor signaling, meiosis and DNA repair, transcriptional factors, RNA metabolism, enzymes, and others. We discussed individual gene mutations found in POI patients and verification of gene functions in gene-deleted model organisms. Decreased expression of some of the POI genes could be responsible for ovarian senescence, especially those essential for DNA repair, meiosis and mitochondrial functions. We propose to set up a candidate gene panel for targeted sequencing in POI patients together with studies on mitochondria-associated genes in middle-aged subfertile patients.

WNT4 Balances Development vs Disease in Gynecologic Tissues and Women's Health

The WNT family of proteins is crucial in numerous developmental pathways and tissue homeostasis. WNT4, in particular, is uniquely implicated in the development of the female phenotype in the fetus, and in the maintenance of müllerian and reproductive tissues. WNT4 dysfunction or dysregulation can drive sex-reversal syndromes, highlighting the key role of WNT4 in sex determination. WNT4 is also critical in gynecologic pathologies later in life, including several cancers, uterine fibroids, endometriosis, and infertility. The role of WNT4 in normal decidualization, implantation, and gestation is being increasingly appreciated, while aberrant activation of WNT4 signaling is being linked both to gynecologic and breast cancers. Notably, single-nucleotide polymorphisms (SNPs) at the WNT4 gene locus are strongly associated with these pathologies and may functionally link estrogen and estrogen receptor signaling to upregulation and activation of WNT4 signaling. Importantly, in each of these developmental and disease states, WNT4 gene expression and downstream WNT4 signaling are regulated and executed by myriad tissue-specific pathways. Here, we review the roles of WNT4 in women's health with a focus on sex development, and gynecologic and breast pathologies, and our understanding of how WNT4 signaling is controlled in these contexts. Defining WNT4 functions provides a unique opportunity to link sex-specific signaling pathways to women's health and disease.

Modulation of folliculogenesis in adult laying chickens by bisphenol A and bisphenol S: Perspectives on ovarian morphology and gene expression

Both bisphenol A (BPA) and its analog bisphenol S (BPS) are industrial chemicals that have been used to make certain plastic products applied in chicken farms, including food and water containers. They are endocrine disrupting chemicals (EDCs) with xenoestrogenic activities and affect reproductive success in many ways. It was hypothesized that BPA and BPS could adversely affect the folliculogenesis in chickens due to their disruption of the estrogen responses, using either genomic or non-genomic mechanisms. This study investigated the deleterious effects of BPA and BPS on the ovaries when adult layer chickens were orally treated with these EDCs at 50 μg/kg body weight, the reference dose for chronic oral exposure of BPA established by the U.S. EPA. The chickens in both BPA and BPS-treated groups showed a decreased number of the preovulatory follicles. BPA-treated chickens showed a significant decrease in the diameter of F1. Additionally, both BPA and BPS treatments increased the infiltrations of lymphocytes and plasma cells in ovaries. Moreover, it was found that the ovaries of BPS-treated chickens weighed the most among the groups. RNA sequencing and subsequent pathway enrichment analysis of differentially expressed genes revealed that both BPA- and BPS-treatment groups showed significant changes in gene expression and pathways related to reproduction, immune function and carcinogenesis. Taken together, both BPA and BPS are potentially carcinogenic and have deleterious effects on the fertility of laying chickens by inducing inflammation, suggesting that BPS may not be a safe replacement for BPA.

Deleterious variants in genes regulating mammalian reproduction in Neanderthals, Denisovans and extant humans

STUDY QUESTION

Were Neanderthals and Denisovans (referred here also as extinct hominidae) carrying deleterious variants in genes regulating reproduction?

SUMMARY ANSWER

The majority of extinct hominidae analyzed here, presented a considerable number of deleterious variants per individual in proteins regulating different aspects of reproduction, including gonad and uterine function, and gametogenesis.

WHAT IS KNOWN ALREADY

Neanderthals, Denisovans and extant humans were interfertile and hybridized while occupying geographically overlapping areas in Europe and Asia. This is evidenced by the small archaic genome component (average ∼2%) present in non-African extant humans.

STUDY DESIGN, SIZE, DURATION

The genome of eight extinct hominidae, together with five human genome databases, plus 44 mothers and 48 fathers (fertile controls), were screened to look for deleterious variants in 1734 protein-coding genes regulating reproduction.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Ancient DNA from six Neanderthals and two Denisovans dated between ∼82 000 and 43 000 calibrated years was retrieved from the public European Nucleotide Archive. The hominins analyzed include Altai, Vindija 33.15, 33.19, 33.25 and 33.26, El Sidron 1253, Denisova 3 and 11. Their DNA was analyzed using the CLC Genomics Workbench 12, by mapping overlapping paired-end reads (Illumina, FASTQ files) to the human genome assembly GRCh37 (hg19) (Vindija 33.19, 33.25, 33.26, Denisova 3 and Denisova 11) or by analyzing BAM files (Altai, El Sidron 1253 and Vindija 33.15) (human genome reference, GRCh37 (hg19)). Non-synonymous reproductive variants were classified as deleterious or tolerated (PolyPhen-2 and SIFT analyses) and were compared to deleterious variants obtained from extant human genome databases (Genome Aggregation Database (GnomAD), 1000 Genomes, the Haplotype Map (HapMap), Single Nucleotide Polymorphism Database (dbSNPs)) across different populations. A genetic intersection between extant or extinct DNA variants and other genetic disorders was evaluated by annotating the obtained variants with the Clinical Variant (ClinVar) database.

MAIN RESULTS AND THE ROLE OF CHANCE

Among the eight extinct hominidae analyzed, a total of 9650 non-synonymous variants (only coverage ≥20 reads included; frameshift mutations were excluded) in 1734 reproductive protein-coding genes were found, 24% of which were classified as deleterious. The majority (73%) of the deleterious alleles present in extant humans that are shared between extant humans and extinct hominidae were found to be rare (<1%) in extant human populations. A set of 8044 variants were found uniquely in extinct hominidae. At the single-gene level, no extinct individual was found to be homozygous for deleterious variants in genes necessary for gamete recognition and fusion, and no higher chance of embryo-lethality (calculated by Mendelian Genetics) was found upon simulated mating between extant human and extinct hominidae compared to extant human-extant human. However, three of the eight extinct hominidae were found to be homozygous for 48-69 deleterious variants in 55 genes controlling ovarian and uterine functions, or oogenesis (AKAP1, BUB1B, CCDC141, CDC73, DUSP6, ESR1, ESR2, PATL2, PSMC3IP, SEMA3A, WT1 and WNT4). Moreover, we report the distribution of nine Neanderthal variants in genes associated with a human fertility phenotype found in extant human populations, one of which has been associated with polycystic ovarian syndrome and primary congenital glaucoma.

LIMITATIONS, REASONS FOR CAUTION

While analyzing archaic DNA, stringent filtering criteria were adopted to screen for deleterious variants in Neanderthals and Denisovans, which could result in missing a number of variants. Such restraints preserve the potential for detection of additional deleterious variants in reproductive proteins in extinct hominidae.

WIDER IMPLICATIONS OF THE FINDINGS

This study provides a comprehensive overview of putatively deleterious variants in extant human populations and extinct individuals occurring in 1734 protein-coding genes controlling reproduction and provides the fundaments for future functional studies of extinct variants in human reproduction.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by the Department of Biological Science and by the Office of Research and Sponsored Programs at the University of Tulsa (Faculty Research Grant and Faculty Research Summer Fellowship) to M.A. and the University of Tulsa, Tulsa Undergraduate Research Challenge (TURC) program to E.L.; no conflict of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

WNT signaling in pre-granulosa cells is required for ovarian folliculogenesis and female fertility

In mammalian ovaries, immature oocytes are reserved in primordial follicles until their activation for potential ovulation. Precise control of primordial follicle activation (PFA) is essential for reproduction, but how this is achieved is unclear. Here, we show that canonical wingless-type MMTV integration site family (WNT) signaling is pivotal for pre-granulosa cell (pre-GC) activation during PFA. We identified several WNT ligands expressed in pre-GCs that act in an autocrine manner. Inhibition of WNT secretion from pre-GCs/GCs by conditional knockout (cKO) of the wntless (Wls) gene led to female infertility. In Wls cKO mice, GC layer thickness was greatly reduced in growing follicles, which resulted in impaired oocyte growth with both an abnormal, sustained nuclear localization of forkhead box O3 (FOXO3) and reduced phosphorylation of ribosomal protein S6 (RPS6). Constitutive stabilization of β-catenin (CTNNB1) in pre-GCs/GCs induced morphological changes of pre-GCs from a squamous into a cuboidal form, though it did not influence oocyte activation. Our results reveal that canonical WNT signaling plays a permissive role in the transition of pre-GCs to GCs, which is an essential step to support oocyte growth.

Oocyte-secreted factors strongly stimulate sFRP4 expression in human cumulus cells

Secreted frizzled-related protein-4 (SFRP4) belongs to a family of soluble ovarian-expressed proteins that participate in female reproduction, particularly in rodents. In humans, SFRP4 is highly expressed in cumulus cells (CCs). However, the mechanisms that stimulate SFRP4 in CCs have not been examined. We hypothesise that oocyte-secreted factors such as growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) are involved in the regulation of SFRP4. Human CCs were collected from patients undergoing fertility treatments and treated with GDF9 or BMP15 or their combination in the presence of FSH or vehicle. FSH treatment significantly decreased SFRP4 mRNA levels when compared with nontreated cells. However, SFRP4 mRNA levels were increased significantly by GDF9 plus BMP15 in a concentration-dependent manner in the presence or absence of FSH. The combination of GDF9 plus BMP15 also increased SFRP4 protein levels and decreased the activity of the β-catenin/T cell factor-responsive promoter significantly. GDF9 plus BMP15 inhibited steroidogenic acute regulatory protein and LH/hCG receptor stimulation by FSH, while treatment with SFRP4 blocked the stimulatory effect of FSH on these genes. The evidence demonstrates that GDF9 and BMP15 act in coordination to stimulate SFRP4 expression and suggests that SFRP4 mediates the anti-luteinising effects of the oocyte in human CCs.

Prenatal exposure of female mice to perfluorononanoic acid delays pubertal activation of the reproductive endocrine axis through enhanced hepatic FGF21 production

The developmental toxicity of perfluorononanoic acid (PFNA), a ubiquitous environmental contaminant, has been associated with the activation of PPARα. This study investigated influence of prenatal exposure to PFNA in pubertal activation of reproductive endocrine axis in female mice and explored underlying molecular mechanisms. Herein, we show that when PFNA (3 mg kg^-1 body weight) was orally administered during gestational days 1-18, dams showed an increase in liver weight and hepatic FGF21 synthesis via PPARα activation, and their female offspring (PFNA mice) showed an increase in liver weight and hepatic FGF21 synthesis from postnatal day (PND) 1 to PND21, which were corrected by the administration of the PPARα antagonist GW6471 from PND1-14 (pup-GW). Expression of vasopressin (VAP) in the hypothalamic suprachiasmatic nucleus (SCN) was reduced in PND14-30 PFNA mice, and could be rescued by pup-GW. Pubertal activation of kisspeptin neurons in anteroventral periventricular nucleus (AVPV) and hypothalamic GnRH neurons in PND21-30 PFNA mice was obviously suppressed, but were recovered by pup-GW or PND21-30 application of VAP. The times of vaginal opening and first estrus were delayed in PFNA mice with a decrease in ovary size and the numbers of primary, secondary and antral follicles, and corpora lutea, which were relieved by pup-GW or application of VAP. The findings indicate that prenatal exposure to PFNA through increased FGF21 production in postnatal female offspring impedes postnatal activation of SCN-VAP neurons, which suppresses pubertal onset in AVPV-kisspeptin neurons and reproductive endocrine axis, leading to delayed puberty and dysfunction of ovaries.

Chronic overload of concentration-dependent iron exerts different effects on ovarian function in C57BL/6J mice†

Overloaded iron can deposit in the reproductive system and impair ovarian function. But few studies have identified the exact effect of overloaded iron on the endocrine function and fertility capacity in female mice. Here, we established iron-overloaded mouse models by intraperitoneal injection of iron dextran to adult female C57BL/6J mice at 0.1 g/kg (LF group), 0.5 g/kg (MF group), and 1.0 g/kg (HF group) concentrations once a week for eight consecutive weeks. We found that overloaded iron resulted in smaller ovaries, as well as accumulated oxidative damages. The endocrine function and follicle development were also impeded in the MF and HF groups. The 10-month breeding trial indicated that (1) Low concentration of iron (0.1 g/kg) wasn't detrimental to the ovary; (2) Middle concentration of iron (0.5 g/kg) impeded the childbearing process, though it could be recovered following the iron excretion; and (3) High concentration of iron (1.0 g/kg) damaged the fertility, even gave rise to sterility. Yet for those fertile mice, litter number and litter size were smaller and the ovarian reserve of their offspring was impaired. Transcriptome profiling results indicated that overloaded iron could compromise ovarian function by disrupting ovarian steroidogenesis, interfering with ovarian microenvironment, and inhibiting Wnt signaling. Taken together, we have demonstrated the effect that chronic concentration-dependent iron overload exerted on mouse ovarian function, which may act as a preliminary basis for further mechanism and intervention investigations.

R-Spondin 2 and WNT/CTNNB1 Signaling Pathways Are Required for Porcine Follicle Development and In Vitro Maturation

The secretion of oocyte-derived paracrine factors, such as R-spondin2, is an essential mechanism for follicle growth by promoting the proliferation and differentiation of cumulus cells around oocytes. In the present study, we aimed to identify the effect of R-spondin2 during follicular development. First, R-spondin2-related factors (R-spondin2, CTNNB1, LGR4, and LGR5) were identified through immunofluorescence in porcine ovarian tissue. CTNNB1 was expressed in ooplasm, and CTNNB1 and LGR4 were expressed in granulosa cells. In addition, R-spondin2, LGR4, and LGR5 were expressed in the theca interna. These results imply that these proteins play a major role in porcine follicular development. In addition, the effects of R-spondin2 on the in vitro maturation process of porcine cumulus oocyte complexes and subsequent embryonic development were confirmed. A treatment of 100 ng/mL R-spondin2 in the in vitro maturation (IVM) process increased nuclear maturation and increased the expression of EGFR mRNA in cumulus cells. The EGFR-ERK signal is essential for oocyte maturation, ovulation, and luteinization. R-spondin2 treatment also increased the expression of CTNNB1 and EGFR in primary cultured cumulus cells. In conclusion, RSPO2 and WNT/CTNNB1 signaling pathways are required for porcine follicle development and are predicted to be involved in the EGFR-ERK signaling pathway.

The function of Wls in ovarian development

WNT ligand transporter Wls is essential for the WNT dependent developmental and pathogenic processes. The spatiotemporal expression pattern of Wls was investigated in this study. Immature female mice (21-22 days old) were treated with 5 IU, pregnant mare's serum gonadotrophin (PMSG) to stimulate follicular development, followed 48 h later by injection with 5 IU, human chorionic gonadotrophin (hCG) to induce ovulation. The expression of Wls was stimulated in granulosa cells and the forming corpus luteum after hCG administration. To study the function of Wls, the Amhr2tm3(cre)Bhr strain was used to target deletion of Wls in granulosa cells. The deletion of Wls caused a significant decrease in the fertility of WlsAmhr2-Cre female mice. In female WlsAmhr2-Cre mice, decreased ovarian size and number of antral follicles were found. The number of corpus luteum in immature PMSG/hCG primed WlsAmhr2-Cre mice was much less than that in the control group. Compared with control animals, WlsAmhr2-Cre mice have lower serum progesterone levels. RNA sequencing was used to identify genes regulated by Wls after hCG treatment. Several genes known to be critical for follicle development and steroidogenesis were significantly down-regulated, such as Fshr, Lhcgr, Sfrp4, Inhba, Cyp17a1, Hsd3b1, and Hsd17b7. The expression of WNT signaling downstream target genes, Bmp2 and Cyp19a1, also decreased significantly in WlsAmhr2-Cre ovary. In summary, the findings of this study suggest that Wls is critical for female fertility and luteinization.

SHP2 Nuclear/Cytoplasmic Trafficking in Granulosa Cells Is Essential for Oocyte Meiotic Resumption and Maturation

Src-homology-2-containing phosphotyrosine phosphatase (SHP2), a classic cytoplasmic protein and a major regulator of receptor tyrosine kinases and G protein-coupled receptors, plays a significant role in preimplantation embryo development. In this study, we deciphered the role of SHP2 in the somatic compartment of oocytes during meiotic maturation. SHP2 showed nuclear/cytoplasmic localization in bovine cumulus and human granulosa (COV434) cells. Follicle-stimulating hormone (FSH) treatment significantly enhanced cytoplasmic SHP2 localization, in contrast to the E₂ treatment, which augmented nuclear localization. Enhanced cytoplasmic SHP2 was found to negatively regulate the expression of the ERα-transcribed NPPC and NPR2 mRNAs, which are vital for oocyte meiotic arrest. The co-immunoprecipitation results revealed the presence of the SHP2/ERα complex in the germinal vesicle-stage cumulus-oocyte complexes, and this complex significantly decreased with the progression of meiotic maturation. The complex formation between ERα and SHP2 was also confirmed by using a series of computational modeling methods. To verify the correlation between SHP2 and NPPC/NPR2, SHP2 was knocked down via RNA interference, and NPPC and NPR2 mRNAs were analyzed in the control, E₂, and FSH-stimulated COV434 cells. Furthermore, phenyl hydrazonopyrazolone sulfonate 1, a site-directed inhibitor of active SHP2, showed no significant effect on the ERα-transcribed NPPC and NPR2 mRNAs. Taken together, these findings support a novel nuclear/cytoplasmic role of SHP2 in oocyte meiotic resumption and maturation.

The role of androgen and its related signals in PCOS

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women at reproductive age. However, the underlying pathogenic mechanisms have not been completely understood. Hyperandrogenism is an important clinic feature in patients with PCOS, suggesting its pathologic role in the development and progression of PCOS. However, the actual role of androgen and the related signals in PCOS and PCOS-related complications have not yet been clarified. In this review, we surveyed the origin and effects of androgen on PCOS and the related complications, highlighted the cellular signals affecting androgen synthesis and summarized the pathological processes caused by hyperandrogenism. Our review well reveals the important mechanisms referring the pathogenesis of PCOS and provides important clues to the clinic strategies in patients with PCOS.

Interactive role of Wnt signaling and Zn in regulating testicular function of the common carp, Cyprinus carpio

Wnt signaling is conserved among all species and plays a significant role in various cellular processes including reproduction. The present study identified significant involvement of wnt4a, wnt5b, and wnt8a signaling in the testicular growth of common carp,Cyprinus carpio. Predominant expression of wnt4a, wnt5b, and wnt8a was found in the gonads and Wnt4a was localized in spermatocytes and interstitial cells. Ontogeny and testicular phase-wise analysis signified the importance of wnt isofoms analyzed in this study. Specific pathway activation of Wnt signaling revealed that Wnt4a and Wnt5b act through non-canonical while Wnt8a prefers the canonical pathway. The Wnt signaling regulates several steroidogenic enzyme and testis-related genes which was confirmed by the Wnt blockade experiments. Incidentally, zinc (Zn) is an essential trace element involved in the progression of spermatogenesis in teleosts. In adult male carp, a single administration of Zn at different doses elevated the expression of Wnt and Zn transporter genes and a single-dose (30 μg/g body weight [BW]) of Zn treatment elevated steroidogenic enzyme and testis-related genes which coincided with elevated androgens. Conversely, single-dose administration of Zn chelator to the Zn administered (30 μg/g BW) fish reversed the effects emphasizing a prominent role of Zn in the testicular function perhaps through Wnt signaling. Similar effects were observed in the in vitro experiments using the Zn chelator. Bioaccumulation of Zn and histological analysis revealed the importance of Zn in progression of spermatogenesis and sperm motility. Various assays related to cell viability and proliferation exhibited the role of Zn in promoting spermatogenic cell progression. Flow cytometric analysis confirmed Zn-induced elevation of Wnt and Zn transporter genes in germ and supporting cells. Furthermore, the effects of Zn are dose-related in carp. Taken together, it seems wnt4a, wnt5b, and wnt8a play an important role in testis and exposure of Wnt inhibitor, canonical as well as non-canonical activators, and Zn confirmed that Zn regulates Wnt signaling vis-à-vis promoting spermatogenesis in the common carp.

miR-458b-5p regulates ovarian granulosa cells proliferation through Wnt/β-catenin signaling pathway by targeting catenin beta-1

OBJECTIVE

Ovarian follicular development, which dependent on the proliferation and differentiation of granulosa cells (GCs), is a complex biological process in which miRNA plays an important role. Our previous study showed that miR-458b-5p is associated with ovarian follicular development in chicken. The detailed function and molecular mechanism of miR-458b-5p in GCs is unclear.

METHODS

The luciferase reporter assay was used to verify the targeting relationship between miR-458b-5p and catenin beta-1 (CTNNB1), which is an important transcriptional regulatory factor of the Wnt/β-catenin pathway. The cell counting kit-8 (CCK-8) assay, flow cytometry with propidium iodide (PI) and annexin V-fluorescein isothiocyanate (FITC) labeling were applied to explore the effect of miR-458b-5p on proliferation, cell cycle and apoptosis of chicken GCs. Quantitative real-time polymerase chain reaction and Western blot were used to detect the mRNA and protein expression levels.

RESULTS

We demonstrated that the expression of miR-458b-5p and CTNNB1 showed the opposite relationship in GCs and theca cells of hierarchical follicles. The luciferase reporter assay confirmed that CTNNB1 is the direct target of miR-458b-5p. Using CCK-8 assay and flow cytometry with PI and Annexin V-FITC labeling, we observed that transfection with the miR-458b-5p mimics significantly reduced proliferation and has no effects on apoptosis of chicken GCs. In addition, miR-458b-5p decreased the mRNA and protein expression of CD44 molecule and matrix metallopeptidase 7, which are the downstream effectors of CTNNB1 in Wnt/β-Catenin pathway and play functional roles in cell proliferation.

CONCLUSION

Taken together, the data indicate that miR-458b-5p regulates ovarian GCs proliferation through Wnt/β-catenin signaling pathway by targeting CTNNB1, suggesting that miR-458b-5p and its target gene CTNNB1 may potentially play a role in chicken ovarian follicular development.

Estrogen Regulation of mTOR Signaling and Mitochondrial Function in Invasive Lobular Carcinoma Cell Lines Requires WNT4

Simple Summary

Invasive lobular carcinoma (ILC) is a common but understudied breast cancer subtype. ILC is presumed to be a low-risk disease in part because nearly all ILCs contain the estrogen receptor (ER). However, we previously showed that ER has unique functions in ILC cells, including driving expression of the Wnt ligand WNT4. WNT4 signaling is required for ILC cell proliferation and survival, but the mechanisms and targets of WNT4 signaling in ILC is unknown. We found that WNT4 regulates mTOR signaling via S6 kinase, and controls levels of MCL-1 protein, ultimately regulating mitochondrial function and cellular metabolism. These findings offer new insight into a novel Wnt signaling pathway and identify new targets to inhibit WNT4 signaling as potential treatments against ILC cells.

Abstract

Invasive lobular carcinoma of the breast (ILC) is strongly estrogen-driven and represents a unique context for estrogen receptor (ER) signaling. In ILC, ER controls the expression of the Wnt ligand WNT4, which is critical for endocrine response and anti-estrogen resistance. However, signaling mediated by WNT4 is cell type- and tissue-specific, and has not been explored in ILC. We utilized reverse phase protein array (RPPA) to characterize ER and WNT4-driven signaling in ILC cells and identified that WNT4 mediates downstream mTOR signaling via phosphorylation of S6 Kinase. Additionally, ER and WNT4 control levels of MCL-1, which is associated with regulation of mitochondrial function. In this context, WNT4 knockdown led to decreased ATP production and increased mitochondrial fragmentation. WNT4 regulation of both mTOR signaling and MCL-1 were also observed in anti-estrogen resistant models of ILC. We identified that high WNT4 expression is associated with similar mTOR pathway activation in ILC and serous ovarian cancer tumors, suggesting that WNT4 signaling is active in multiple tumor types. The identified downstream pathways offer insight into WNT4 signaling and represent potential targets to overcome anti-estrogen resistance for patients with ILC.

Updates on molecular and environmental determinants of luteal progesterone production

Progesterone, a critical hormone in reproduction, is a key sex steroid in the establishment and maintenance of early pregnancy and serves as an intermediary for synthesis of other steroid hormones. Progesterone production from the corpus luteum is a tightly regulated process which is stimulated and maintained by multiple factors, both systemic and local. Multiple regulatory systems, including classic mediators of gonadotropin stimulation such as the cAMP/PKA pathway and TGFβ-mediated signaling pathways, as well as local production of hormonal factors, exist to promote granulosa cell function and physiological fine-tuning of progesterone levels. In this manuscript, we provide an updated narrative review of the known mediators of human luteal progesterone and highlight new observations regarding this important process, focusing on studies published within the last five years. We will also review recent evidence suggesting that this complex system of progesterone production is sensitive to disruption by exogenous environmental chemicals that can mimic or interfere with the activities of endogenous hormones.

MiR-214-3p promotes proliferation and inhibits estradiol synthesis in porcine granulosa cells

Background

Granulosa cells (GCs) proliferation and estradiol synthesis significantly affect follicular development. The miR-214-3p expression in the ovarian tissues of high-yielding sows is higher than that in low-yielding sows, indicating that miR-214-3p may be involved in sow fertility. However, the functions and mechanisms of miR-214-3p on GCs are unclear. This study focuses on miR-214-3p in terms of the effects on GCs proliferation and estradiol synthesis.

Results

Our findings revealed that miR-214-3p promotes proliferation and inhibits estradiol synthesis in porcine GCs. MiR-214-3p can increase the percentage of S-phase cells, the number of EdU labeled positive cells, and cell viability. However, E₂ concentration was reduced after miR-214-3p agomir treatment. We also found that miR-214-3p up-regulates the expression of cell cycle genes including cell cycle protein B (Cyclin B), cell cycle protein D (Cyclin D), cell cycle protein E (Cyclin E), and cyclin-dependent kinase 4 (CDK4) at the transcription and translation levels, but down-regulates the mRNA and protein levels of cytochrome P450 family 11 subfamily A member 1 (CYP11A1), cytochrome P450 family 19 subfamily A member 1 (CYP19A1), and steroidogenic acute regulatory protein (StAR) (i.e., the key enzymes in estradiol synthesis). On-line prediction, bioinformatics analysis, a luciferase reporter assay, RT-qPCR, and Western blot results showed that the target genes of miR-214-3p in proliferation and estradiol synthesis are Mfn2 and NR5A1, respectively.

Conclusions

Our findings suggest that miR-214-3p plays an important role in the functional regulation of porcine GCs and therefore may be a target gene for regulating follicular development.