Wnt signaling in the ovary: identification and compartmentalized expression of wnt-2, wnt-2b, and frizzled-4 mRNAs

Ovarian follicle transcriptome dynamics reveals enrichment of immune system process during transition from small to large follicles in cyclic Indian Ghoongroo pigs

Ovarian follicular development is a critical determinant of reproductive performance in litter bearing species like pigs, wherein economic gains depend on litter size. The study aimed to gain insight into the differentially expressed genes (DEGs) and signalling pathways regulating follicular growth and maturation in Ghoongroo pigs. Transcriptome profiling of porcine small follicles (SF) and large follicles (LF) was conducted using NovaSeq600 sequencing platform and DEGs were identified using DESeq2 with threshold of Padj. < 0.05 and log2 fold change cut off 0.58 (LF vs. SF). Functional annotations and bioinformatics analysis of DEGs were performed to find out biological functions, signalling pathways and hub genes regulating follicular dynamics. Transcriptome analysis revealed 709 and 479 genes unique to SF and LF stages, respectively, and 11,993 co-expressed genes in both the groups. In total, 507 DEGs (284 upregulated and 223 downregulated) were identified, which encoded for diverse proteins including transcription factors (TFs). These DEGs were functionally linked to response to stimulus, lipid metabolic process, developmental process, extracellular matrix organisation along with the immune system process, indicating wide-ranging mechanisms associated with follicular transition. The enriched KEGG pathways in LF stage consisted of ovarian steroidogenesis, cholesterol and retinol metabolism, cell adhesion molecules, cytokine receptor interaction and immune signalling pathways, depicting intra-follicular control of varied ovarian function. The hub gene analysis revealed APOE, SCARB1, MMP9, CYP17A1, TYROBP as key regulators of follicular development. This study identified candidate genes and TFs providing steroidogenic advantage to LFs which makes them fit for selection into the ovulatory pool of follicles.

Increased Hepatocyte Growth Factor Secretion by Placenta-Derived Mesenchymal Stem Cells Improves Ovarian Function in an Ovariectomized Rat Model via Vascular Remodeling by Wnt Signaling Activation

The vascular network contributes to the development of follicles. However, the therapeutic mechanism between vascular remodeling and ovarian functions is still unclear. Therefore, we demonstrated whether increased HGF by placenta-derived mesenchymal stem cells (PD-MSCs) improves ovarian function in an ovariectomized rat model via vascular remodeling by Wnt signaling activation. We established a half-ovariectomized rat model in which damaged ovaries were induced by ovariectomy of half of each ovary, and PD-MSCs (5 × 105 cells) were transplanted by intravenous injection. Three weeks after transplantation, rats in all groups were sacrificed. We examined the secretion of HGF by PD-MSCs through culture medium. The vascular structure in injured ovarian tissues was restored to a greater extent in the PD-MSC transplantation (Tx) group than in the nontransplantation (NTx) group (* p < 0.05). The expression of genes related to Wnt signaling (e.g., LRP6, GSK3β, β-catenin) was significantly increased in the Tx group compared to the NTx group (* p < 0.05). However, the expression of genes related to vascular permeability (e.g., Asef, ERG3) was significantly decreased in the Tx group compared to the NTx group (* p < 0.05). Follicular development was improved in the Tx group compared to the NTx group (* p < 0.05). Furthermore, to evaluate vascular function, we cocultivated PD-MSCs after human umbilical vein endothelial cells (HUVECs) with lipopolysaccharide (LPS), and we analyzed the vascular formation assay and dextran assay in HUVECs. Cocultivation of PD-MSCs with injured HUVECs enhanced vascular formation and decreased endothelial cell permeability (* p < 0.05). Also, cocultivation of PD-MSCs with explanted ovarian tissues improved follicular maturation compared to cocultivation of the Wnt inhibitor-treated PD-MSCs with explanted ovarian tissues. Therefore, HGF secreted by PD-MSCs improved ovarian function in rats with ovarian dysfunction by decreasing vascular permeability via Wnt signaling.

A PITX2-HTR1B pathway regulates the asymmetric development of female gonads in chickens

All female vertebrates develop a pair of ovaries except for birds, in which only the left gonad develops into an ovary, whereas the right gonad regresses. Previous studies found that the transcription factor Paired-Like Homeodomain 2 (PITX2), a key mediator for left/right morphogenesis in vertebrates, was also implicated in asymmetric gonadal development in chickens. In this study, we systematically screened and validated the signaling pathways that could be targeted by Pitx2 to control unilateral gonad development. Integrated chromatin immunoprecipitation sequencing (ChIP-seq) and RNA sequencing (RNA-seq) analyses indicated that Pitx2 directly binds to the promoters of genes encoding neurotransmitter receptors and leads to left-biased expression of both serotonin and dopamine receptors. Forcibly activating serotonin receptor 5-Hydroxytryptamine Receptor 1B (HTR1B) signaling could induce ovarian gene expression and cell proliferation to partially rescue the degeneration of the right gonad. In contrast, inhibiting serotonin signaling could block the development of the left gonad. These findings reveal a PITX2-HTR1B genetic pathway that guides the left-specific ovarian growth in chickens. We also provided new evidence showing neurotransmitters stimulate the growth of nonneuronal cells during the early development of reproductive organs well before innervation.

microRNA-627-5p inhibits colorectal cancer cell proliferation, migration and invasion by targeting Wnt2

BACKGROUND

microRNA-627-5p (miR-627-5p) dysregulation has been observed in several cancer types, such as hepatocellular carcinoma, oral squamous cell carcinoma, glioblastoma multiforme, and gastric cancer. The biological function of miR-627-5p in colorectal cancer (CRC) growth and metastasis is yet unclear.

AIM

To investigate the effects of miR-627-5p on the malignant biological properties of colorectal malignant tumour cells by targeting Wnt2.

METHODS

The levels of miR-627-5p in colorectal tumour tissues were assessed in Gene Expression Omnibus datasets. In order to identify Wnt2 transcript expression in CRC tissues, quantitative real-time polymerase chain reaction (qRT-PCR) analysis was used. Luciferase reporter tests were used to explore whether miR-627-5p might potentially target Wnt2. Wnt2 transcript and protein levels were detected in CRC cells with high miR-627-5p expression. To learn more about how miR-627-5p affects CRC development, migration, apoptosis, and invasion, functional experiments were conducted. Cotransfection with the overexpression vector of Wnt2 and miR-627-5p mimics was utilized to verify whether overexpression of Wnt2 could cancel the impact of miR-627-5p in CRC. Western blot and qRT-PCR were conducted to investigate the effects of miR-627-5p on the Wnt/β-catenin signalling pathway.

RESULTS

miR-627-5p was notably decreased in colorectal tumour tissues, while the gene level of Wnt2 was notably upregulated. A dual luciferase reporter assay revealed that miR-627-5p specifically targets the 3’-untranslated regions of Wnt2 and miR-627-5p upregulation markedly reduced the protein and gene expression of Wnt2 in CRC cells. In vitro gain-of-function assays displayed that miR-627-5p overexpression decreased CRC cells’ capabilities to invade, move, and remain viable while increasing apoptosis. Wnt2 overexpression could reverse the suppressive functions of miR-627-5p. Moreover, upregulation of miR-627-5p suppressed the transcript and protein levels of the downstream target factors in the canonical Wnt/β-catenin signalling, such as c-myc, CD44, β-catenin, and cyclinD1.

CONCLUSION

miR-627-5p acts as a critical inhibitory factor in CRC, possibly by directly targeting Wnt2 and negatively modulating the Wnt/β-catenin signalling, revealing that miR-627-5p could be a possible treatment target for CRC.

Allelic to genome wide perspectives of swine genetic variation to litter size and its component traits

Litter size is a complex and sex limited trait that depends on various biological, managemental and environmental factors. Owing to its low heritability it is inefficaciously selected by traditional methods. However, due to higher heritability of ovulation rate and embryo survival, selection based on component traits of litter size is advocated. QTL analysis and candidate gene approach are among the various supplementary/alternate strategies for selection of litter size. QTL analysis is aimed at identifying genomic regions affecting trait of interest significantly. Candidate gene approach necessitates identification of genes potentially affecting the trait. There are various genes that significantly affect litter size and its component traits viz. ESR, LEP, BF, IGFBP, RBP4, PRLR, CTNNAL1, WNT10B, TCF12, DAZ, and RNF4. These genes affect litter size in a complex interacting manner. Lately, genome wide association study (GWAS) have been utilized to unveil the genetic and biological background of litter traits, and elucidate the genes governing litter size. Favorable SNPs in these genes have been identified and offers a scope for inclusion in selection programs thereby increasing breeding efficiency and profit in pigs. The review provides a comprehensive coverage of investigations carried out globally to unravel the genetic variation in litter size and its component traits in pigs, both at allelic and genome wide level. It offers a current perspective on different strategies including the profiling of candidate genes, QTLs, and genome wide association studies as an aid to efficient selection for litter size and its component traits.

Hippo Signaling in the Ovary: Emerging Roles in Development, Fertility, and Disease

Emerging studies indicate that the Hippo pathway, a highly conserved pathway that regulates organ size control, plays an important role in governing ovarian physiology, fertility, and pathology. Specific to the ovary, the spatiotemporal expression of the major components of the Hippo signaling cascade are observed throughout the reproductive lifespan. Observations from multiple species begin to elucidate the functional diversity and molecular mechanisms of Hippo signaling in the ovary in addition to the identification of interactions with other signaling pathways and responses to various external stimuli. Hippo pathway components play important roles in follicle growth and activation, as well as steroidogenesis, by regulating several key biological processes through mechanisms of cell proliferation, migration, differentiation, and cell fate determination. Given the importance of these processes, dysregulation of the Hippo pathway contributes to loss of follicular homeostasis and reproductive disorders such as polycystic ovary syndrome (PCOS), premature ovarian insufficiency, and ovarian cancers. This review highlights what is currently known about the Hippo pathway core components in ovarian physiology, including ovarian development, follicle development, and oocyte maturation, while identifying areas for future research to better understand Hippo signaling as a multifunctional pathway in reproductive health and biology.

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.

Wnt antagonist as therapeutic targets in ovarian cancer

Ovarian cancer is a fatal malignancy in women with a low survival rate that demands new therapeutic paradigms. Cancer cells acquire various exclusive alterations to proliferate, invade, metastasize, and escape cell death, acting independently of growth-inducing or growth-inhibiting signals. The nature of cellular signaling in tumorigenesis is interwoven. Wnt signaling is an evolutionarily conserved signaling cascade that has been shown to regulate ovarian cancer pathogenesis. The molecular mechanism of Wnt signaling underlying the development of ovarian cancer, drug resistance, and relapse is not completely understood. Extracellularly secreted Wnt signaling inhibitors are crucial regulators of ovarian cancer tumorigenesis and malignant properties of cancer stem cells. Wnt inhibitors arbitrated modifications affecting Wnt pathway proteins on the cell membranes, in the cytoplasm, and in the nucleus have been shown to span essential contributions in the initiation, progression, and chemoresistance of ovarian cancer. Although many extrinsic inhibitors developed targeting the downstream components of the Wnt signaling pathway, investigating the molecular mechanisms of endogenous secreted inhibitors might substantiate prognostic or therapeutic biomarkers development. Given the importance of Wnt signaling in ovarian cancer, more systematic studies combined with clinical studies are requisite to probe the precise mechanistic interactions of Wnt antagonists in ovarian cancer. This review outlines the latest progress on the Wnt antagonists and ovarian cancer-specific regulators such as micro-RNAs, small molecules, and drugs regulating these Wnt antagonists in ovarian tumourigenesis.

Overexpression of Lin28a induces a primary ovarian insufficiency phenotype via facilitation of primordial follicle activation in mice

Lin28a is an RNA binding protein and increasing evidence has indicated its role in regulating female fertility. Lin28a has been reported to be involved in ovarian follicle activation. However, its role and mechanisms in regulating primordial follicle activation have not yet been explored. To test whether overexpression of Lin28a activates ovarian primordial follicles, studies were conducted in wild type (WT) and Lin28a Tg mice. Female Lin28a Tg mice at 4-month old exhibited significantly smaller litter size and fewer ovulated oocytes when compared with the WT mice. By 6-month of age, these parameters in Lin28a Tg mice were less than 20% of the WT mice. At postnatal day (PD) 14, the number of primordial follicles was significantly decreased but the number of primary follicles was significantly increased in the transgenic mice. The number of primordial follicles, secondary and antral follicles in these mice were drastically reduced at PD21. In the ovary of Lin28a Tg mice, there were activation of Wnt/β-catenin signaling and its downstream mTOR pathway. Interestingly, overexpression of Lin28a, which can also act as transcriptional activator, activated Wnt signaling through enhancing the transcription of Wnt co-receptor LRP5. In conclusion, overexpression of Lin28a induced a primary ovarian insufficiency phenotype in long term via facilitating Wnt/β-catenin signaling leading to activation of primordial follicles.

FSH stimulated bovine granulosa cell steroidogenesis involves both canonical and noncanonical WNT signaling

Gonadotrophins play key roles in follicular development; however, the underlying molecular mechanisms are not fully understood. Follicle stimulating hormone (FSH) regulation of aromatase and subsequent estradiol (E₂) production relies on β-catenin, a key effector of WNT signaling. We previously demonstrated that treatment with the canonical WNT inhibitor, IWR-1, reduced FSH induced bovine granulosa cell E₂ production in vitro. Here we demonstrated that intrafollicular injection in vivo with IWR-1 alters steroidogenesis and triggers a significant decrease in estrogen to progesterone ratio in the IWR-1 treated follicles compared to diluent injected control follicles. We next examined markers of canonical and noncanonical WNT signaling in dominant and subordinate follicles collected at different stages of follicular development and showed that protein for both CTNNB1 (canonical pathway) and phosphorylated (p)-LEF1 (noncanonical pathway) was significantly elevated in dominant compared to subordinate follicles at the early dominance stage of development. Therefore, we hypothesized that canonical and/or noncanonical WNT ligands modulate FSH stimulated E₂ production. Hence, we examined the effects of specific WNT ligands on FSH stimulated E₂ production in the absence of endogenous WNT production in vitro. Universal WNT signaling inhibitor, LGK-974 was able to inhibit FSH stimulation of E₂ and reduce the abundance of proteins linked to canonical and noncanonical WNT pathway activation. Supplementation with the canonical ligand WNT2b did not affect the inhibitory effects of LGK-974 on FSH stimulated E₂ production but rescued the LGK-974 mediated inhibition of CTNNB1 (canonical pathway) but not p-LEF1, p-JNK or p-P38 abundance (noncanonical pathway) abundance. In contrast, WNT5a treatment rescued FSH stimulated estradiol production and indices of activation of both the canonical (CTNNB1) and noncanonical (p-LEF1, p-JNK and p-P38) WNT signaling pathways in LGK-974 treated granulosa cells. Taken together, these results suggest that both canonical and noncanonical WNT pathways activation is linked to FSH stimulation of E₂ production by bovine granulosa cells.

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.

Identification of wnt2 in the pearl mussel Hyriopsis cumingii and its role in innate immunity and gonadal development

Wnt2 is a significant factor in the Wnt signaling pathway, which is associated with a variety of physiological activities, including inflammatory response, cell apoptosis, reproductive system development, and cell differentiation. Hyriopsis cumingii is the main pearl breeding mussel in China. However, the role of wnt2 in this species remains unclear. In this study, wnt2 from H. cumingii was cloned and identified. The full-length cDNA of wnt2 is 1524 bp, containing a 963 bp open reading frame (ORF), encoding 320 amino acid residues. The tissue distribution of H. cumingii indicated that wnt2 was predominantly highly expressed in the ovary and gill. And the expression profile after Aeromonas hydrophila or LPS injection indicated that wnt2 was up-regulated in gill, suggesting its role in the innate immune response. The expression of wnt2 was high at 4-month-old of early gonadal development and throughout ovarian development. In situ hybridization (ISH) showed significant hybridization signals on the gills and mature eggs of female gonads. In addition, miR-1988b-5p was found to negatively regulate wnt2 to affect the expression of key genes (frizzled-5, ctnnb1, and tcf7l) in the Wnt signaling pathway. Thus, these findings suggest a key role for wnt2 in immune regulation and gonadal development in H. cumingii.

Comparative transcriptomic analysis reveals the gonadal development-related gene response to environmental temperature in Mauremys mutica

The Asian yellow pond turtle (Mauremys mutica) displays temperature-dependent sex determination (TSD), in which incubation temperature during embryonic development determines the sexual fate of the individual. However, the mechanism of the sex determination/differentiation of Mauremys mutica remains a mystery. Here, we first analyzed the temperature-specific gonadal transcriptomes of Mauremys mutica prior to gonad formation and gonads during the thermosensitive period. We uncovered a list of candidates that respond to temperature stimuli enriched in several categories, such as heat shock protein family members dnajb6a, dnaja4, hspa8 and hsp90aa1, temperature sensor genes mmp17 and mmp28, and putative novel temperature-responsive genes tmco6, gria3 and eif3f. Notably, striking differences were identified in the expression profiles of genes underlying sexual development, such as tex15, insr, igf1r, cirbp, esr1, dmrt2 and Serpinh1. Moreover, we analyzed the similarity and divergence of the timecourse of gene expression among Mauremys mutica and two other reported TSD turtles (Trachemys scripta and Chrysemys picta). The shared genes revealed the common gonad-specific regulatory mechanisms existing in these three TSD turtles that initiate their sexual development. Therefore, our findings could provide basic data to elucidate the mechanisms of sex determination/differentiation of M. mutica, even contributing to further understanding of these mechanisms in other TSD turtles.

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.

Novel variants in the stem cell niche factor WNT2B define the disease phenotype as a congenital enteropathy with ocular dysgenesis

WNT2B is a member of the Wnt family, a group of signal transduction proteins involved in embryologic development and stem cell renewal and maintenance. We recently reported homozygous nonsense variants in WNT2B in three individuals with severe, neonatal-onset diarrhea, and intestinal failure. Here we present a fourth case, from a separate family, with neonatal diarrhea associated with novel compound heterozygous WNT2B variants. One of the two variants was a frameshift variant (c.423del [p.Phe141fs]), while the other was a missense change (c.722 G > A [p.G241D]) that we predict through homology modeling to be deleterious, disrupting post-translational acylation. This patient presented as a neonate with severe diet-induced (osmotic) diarrhea and growth failure resulting in dependence on parenteral nutrition. Her gastrointestinal histology revealed abnormal cellular architecture particularly in the stomach and colon, including oxyntic atrophy, abnormal distribution of enteroendocrine cells, and a paucity of colonic crypt glands. In addition to her gastrointestinal findings, she had bilateral corneal clouding and atypical genital development later identified as a testicular 46,XX difference/disorder of sexual development. Upon review of the previously reported cases, two others also had anterior segment ocular anomalies though none had atypical genital development. This growing case series suggests that variants in WNT2B are associated with an oculo-intestinal (and possibly gonadal) syndrome, due to the protein's putative involvement in multiple developmental and stem cell maintenance pathways.

Long noncoding RNAs profiling in ovary during laying and nesting in Muscovy ducks (Cairina moschata)

There are recent reports of the important functions of long noncoding RNAs (lncRNAs) in female reproductive and ovarian development. Studies in which there was characterization of lncRNAs in the ovaries of laying compared with nesting poultry, however, are limited. In this study, RNA libraries were constructed by obtaining sequencing data of ovarian tissues from laying and nesting Muscovy ducks. In the ovarian tissues of Muscovy ducks, a total of 334 differentially abundant mRNA transcripts (DEGs) and 36 differentially abundant lncRNA transcripts were identified in the nesting period, when compared with during the laying period. These results were subsequently validated by qRT-PCR using nine randomly-selected lncRNAs and six randomly-selected DAMTs. Furthermore, the cis- and trans-regulatory target genes of differentially abundant lncRNA transcripts were identified, and lncRNA-gene interaction networks of 34 differentially abundant lncRNAs and 263 DEGs were constructed. A total of 7601 lncRNAs neighboring 10,542 protein-coding genes were identified and found to be enriched in the Wnt signaling pathway and oocyte meiosis pathways associated with follicular development. Overall, only 11 cis-targets and 57 mRNA-mRNA except trans-targets were involved in the lncRNA-gene interaction networks. Based on the interaction networks, nine DEGs were trans-regulated by differentially abundant lncRNAs and 20 differentially abundant lncRNAs were hypothesized to have important functions in the regulation of broodiness in Muscovy ducks. In this study, a predicted interaction network of differentially abundant lncRNAs and DEGs in Muscovy ducks was constructed for the first time leading to an enhanced understanding of lncRNA and gene interactions regulating broodiness.

Copper and Selenium stimulates CYP19A1 expression in caprine ovarian granulosa cells: possible involvement of AKT and WNT signalling pathways

The role of copper and selenium on activation of estradiol synthesis pathways viz. PKA/AKT/WNT is not clearly elucidated. On this background we attempt to elcuiated the role of copper and selenium on mRNA expression of genes associated with estradiol synthesis in caprine ovarian granulose cell models. Ovarian granulosa cells from medium (3-5 mm) sized follicles were aspirated and distributed separately to different groups. Group I: control, Group II: cupric chloride (Cu: 0.5 mM), Group III: sodium selenite (Se: 100 ng/ml), Group IV: Cu + Se. The cells (10⁵/well) were cultured in 96 well plate in the base culture medium of MEMα comprising of nonessential amino acids (1.1 mM), FSH (10 ng/mL), transferrin (5 µg/mL), IGF-I (2 ng/mL), androstenedione (10^-6 M), penicillin (100 IU/mL), streptomycin (0.1 mg/mL) and fungizone (0.625 µl/mL) and insulin (1 ng/mL). The cells were incubated in a carbondioxide incubator (38 °C, 5% CO₂, 95% RH). The medium was changed on alternate days and cells were harvested on day 6. Day 6 media was used for estimation of estradiol. The RNA isolated form harvested cells was used for qPCR assay. There was no significant (p > 0.05) difference in estradiol concentration between groups. The mRNA expression of AKT1, CYP19A1, WNT2 & 4, FZD6 and APC2 were significantly (p < 0.05) higher in Cu and Cu + Se groups compared to control. Whereas, the mRNA transcript of DVL1 and CSNK1 was significantly (p < 0.05) higher in Cu + Se group compared to control. Incontrast, no significant difference in mRNA expression of PRKAR1A and CTNNB1 was noticed. Our study support a key role of copper and selenium in activation of AKT and WNT signalling pathway that further lead to increase in the mRNA expression of CYP19A1.

5-Fluorouracil disrupts ovarian preantral follicles in young C57BL6J mice

PURPOSE

5-Fluorouracil (5-FU), an anti-cancer drug, has been used for hepatoblastoma (HB) chemotherapy in children, who may have impaired  ovarian follicle pool reserve with lasting effects to reproduction. Therefore, this study aimed to investigate 5-FU effects on survival, growth, and morphology of ovarian preantral follicles from C57BL6J young mice.

METHODS

Experiments were carried-out both in vivo and in vitro. Mice were treated with 5-FU injection (450 mg/kg i.p) or saline and sacrificed 3 days after to obtain ovaries for histology and molecular biology. Ovaries for in vitro studies were obtained from unchallenged mice and cultured under basic culture medium (BCM) or BCM plus 5-FU (9.2, 46.1, 92.2 mM). Preantral follicles were classified according to developmental stages, and as normal or degenerated. To assess cell viability, caspase-3 immunostaining was performed. Transcriptional levels for apoptosis (Bax, Bcl2, p53, Bax/Bcl2) and Wnt pathway genes (Wnt2 and Wnt4) were also analyzed. Ultrastructural analyses were carried-out on non-cultured ovaries. In addition, β-catenin immunofluorescence was assessed in mouse ovaries.

RESULTS

The percentage of all-types normal follicles was significantly lower after 5-FU challenge. A total loss of secondary normal follicles was found in the 5-FU group. The highest 5-FU concentrations reduced the percentage of cultured normal primordial follicles. Large vacuoles were seen in granulosa cells and ooplasm of preantral follicles by electron microscopy. A significantly higher gene expression for Bax and Bax/Bcl2 ratio was seen after 5-FU treatment. A marked reduction in β-catenin immunolabeling was seen in 5-FU-challenged preantral follicles. In the in vitro experiments, apoptotic and Wnt gene transcriptions were significantly altered.

CONCLUSION

Altogether, our findings suggest that 5-FU can deleteriously affect the ovarian follicle reserve by reducing preantral follicles survival.

G Protein-Coupled Estrogen Receptor Correlates With Dkk2 Expression and Has Prognostic Impact in Ovarian Cancer Patients

PURPOSE

Wnt pathway modulator Dickkopf 2 (Dkk2) and signaling of the G protein-coupled estrogen receptor (GPER) seem to have essential functions in numerous cancer types. For epithelial ovarian cancer (EOC), it has not been proven if either Dkk2 or the GPER on its own have an independent impact on overall survival (OS). So far, the correlation of both factors and their clinical significance has not systematically been investigated before.

METHODS

Expression levels of Dkk2 were immunohistochemically analyzed in 156 patient samples from different histologic subtypes of EOC applying the immune-reactivity score (IRS). Expression analyses were correlated with clinical and pathological parameters to assess for prognostic relevance. Data analysis was performed using Spearman's correlations, Kruskal-Wallis-test and Kaplan-Meier estimates.

RESULTS

Highest Dkk2 expression of all subtypes was observed in clear cell carcinoma. In addition, Dkk2 expression differed significantly (p<0.001) between low and high grade serous ovarian cancer. A significant correlation of Dkk2 with the cytoplasmic GPER expression was noted (p=0.001) but not for the nuclear estrogen receptor alpha (ERα) or beta (ERβ). Patients exhibiting both, high expression Dkk2 (IRS>4) and GPER (IRS>8), had a significantly better overall survival compared to patients with low expression (61 months vs. 33 months; p=0.024).

CONCLUSION

Dkk2 and GPER expression correlates in EOC and combined expression of both is associated with improved OS. These findings underline the clinical significance of both pathways and indicate a possible prognostic impact as well as a potential for treatment strategies addressing interactions between estrogen and Wnt signaling in ovarian cancer.

Conditional deletion of Wntless in granulosa cells causes impaired corpora lutea formation and subfertility

WNT proteins are widely expressed in the murine ovaries. WNTLESS is a regulator essential for all WNTs secretion. However, the complexity and overlapping expression of WNT signaling cascades have prevented researchers from elucidating their function in the ovary. Therefore, to determine the overall effect of WNT on ovarian development, we depleted the Wntless gene in oocytes and granulosa cells. Our results indicated no apparent defect in fertility in oocyte-specific Wntless knockout mice. However, granulosa cell (GC) specific Wntless deletion mice were subfertile and recurred miscarriages. Further analysis found that GC-specific Wntless knockout mice had noticeably smaller corpus luteum (CL) in the ovaries than control mice, which is consistent with a significant reduction in luteal cell marker gene expression and a noticeable increase in apoptotic gene expression. Also, the deletion of Wntless in GCs led to a significant decrease in ovarian HCGR and β-Catenin protein levels. In conclusion, Wntless deficient oocytes had no discernible impact on mouse fertility. In contrast, the loss of Wntless in GCs caused subfertility and impaired CL formation due to reduced LHCGR and β-Catenin protein levels, triggering GC apoptosis.

Protective Effects of Puerarin on Premature Ovarian Failure via Regulation of Wnt/β-catenin Signaling Pathway and Oxidative Stress

This study was designed to investigate the protective effects of puerarin (PUE), which work via the Wnt/β-catenin signaling pathway, and oxidative stress in the premature ovarian failure (POF) model. Two-month-old female mice were randomly divided into four groups. One group was used as the control, and the other three groups were injected with cyclophosphamide and busulfan to create POF models. Two POF treatment groups were gavaged with 100 or 200 mg/kg PUE for 28 days. Next, the ovaries were fixed, and the numbers of different stage follicles were measured, and the ovarian surface epithelium (OSE) was collected. Oct4 and Mvh expression, Wnt/β-catenin signaling pathway activity, the oxidative stress factors SOD2 and Nrf2, and the apoptosis-related proteins Bcl-2 and Bax were detected by IHC, RT-QPCR, and western blotting. We found that the number of follicles, Oct4 and Mvh expression, and Wnt/β-catenin-signaling activity were reduced in the POF groups (p < 0.05 or p < 0.001). After PUE treatment, the follicle number and the primordial follicle ratio increased (p < 0.01), while the atresia ratio decreased (p < 0.01). In addition, the expression levels of Oct4, Mvh, Wnt1, β-catenin, cyclin D1, SOD2, and Nrf2 showed obvious recovery compared with levels in the POF group (p < 0.01, p < 0.05, or p < 0.001). The Bcl-2/Bax ratio in the POF model had reduced by about 60% compared with the control group (p < 0.001) and improved by about 50% after PUE treatment (p < 0.001). In conclusion, PUE may improve the survival of female reproductive stem cells (FGSCs) and play a protective role against POF via a mechanism involving the Wnt/β-catenin signaling pathway, as well as relieving oxidative stress. Further investigations should focus on the culture of oocytes and FGSCs in vitro in a PUE environment with inhibitors or agonists of the Wnt signaling pathway.

Genome-wide association analysis reveals the genetic locus for high reproduction trait in Chinese Arbas Cashmere goat

BACKGROUND

Litter size is the most important reproductive trait which plays a crucial role in goat production. Therefore, improvement of litter size trait has been of increasing interest in goat industry as small improvement in litter size may lead to large profit. The recent Cashmere goat breeding program produced a high-reproductive genetic line of Arbas Cashmere goat. But the genetic mechanism of high reproduction rate remains largely unknown in this Chinese native goat breed. To address this question, we performed a genome-wide association studies (GWAS) using two groups of goats varying in fecundity.

OBJECTIVES

Our study was aimed to investigate the significant SNPs and genes associated with high reproduction trait in Inner Mongolia Arbas Cashmere Goat.

METHODS

We used logistic model association to perform GWAS using 47 goats from high fecundity group (~ 190%) and 314 goats from low fecundity group (~ 130%) of the Arbas Cashmere goat breed.

RESULTS

We identified 66 genomic regions associated with genome wide significant level wherein six loci were found to be associated with reproduction traits. Further analysis showed that five key candidate genes including KISS1, KHDRBS2, WNT10B, SETDB2 and PPP3CA genes are involved in goat fecundity trait. Gene ontology enrichment analysis revealed that several biological pathways could be involved in the variation of fecundity in female goats.

CONCLUSIONS

The identified significant SNPs or genes provide useful information about the underlying genetic control of fecundity trait which will be helpful to use them in goat breeding programs for improving the reproductive efficiency of goats.

Functional analysis of the Frzb2 gene in Schistosoma japonicum

Schistosomiasis is a globally important helminthic disease of humans and animals, and it is the second most common parasitic disease after malaria. Eggs produced by mature females are responsible for the disease’s occurrence and spread. Frzb2, a secreted frizzled-related protein, can inhibit Wnt signalling by competitive binding to the specific frizzled protein receptor. In this study, the complete gene sequence of SjFrzb2 was obtained by using 3′-rapid amplification of cDNA ends technology. SjFrzb2 transcript levels at different stages of S. japonicum maturation were evaluated by quantitative real-time RT-PCR analysis. SjFrzb2 was expressed at all developmental stages examined and exhibited the highest transcription level in 7-day-old worms, then gradually decreased during the growth and developmental stages to reach the lowest level at 18 days post-infection. SjFrzb2 gene expression was higher in female worms than in male worms and was significantly higher in female worms from a single-sex infection than in female worms from a bisexual infection. The functions of SjFrzb2 were explored via a small interfering RNA-based gene silencing approach and the soaking method. The results showed that SjFrzb2 gene knockdown impaired the growth and development of S. japonicum in mice, affecting not only the survival and morphological structure of the worms but also their reproductive ability and the viability of the produced eggs. Collectively, these observations imply that Frzb2 may be a novel target for the development of immuno- and/or small molecule-based therapeutics to control schistosomiasis fecundity and transmission.

Regulation of carcinogenesis and modulation through Wnt/β-catenin signaling by curcumin in an ovarian cancer cell line

The secreted frizzled-related protein 5 gene (SFRP5) that antagonize the Wnt/β-catenin signaling is frequently inactivated by promoter methylation and oncogenic activation of the Wnt signaling pathway is common in many cancers. The curcumin-rich Curcuma longa has been reported to potent anti-cancer property involved in epigenetic regulation to inhibit tumor suppressor gene methylation and re-expression. In a compounds screening, we found that curcumin can inhibit Wnt/β-catenin signaling. Therefore, the aim of this study was to investigate the effects of curcumin on SFRP5 DNA methylation modification in an ovarian cancer cell line (SKOV3). SKOV3 cells were treated with DMSO, 10 μM 5-aza-2′-deoxycytidine (DAC), 5 μM DAC, 20 μM curcumin, and 20 μM curcumin combined with 5 μM DAC for 96 hours, following which RNA and proteins were extracted for further analysis. The results showed that curcumin combined with 5 μM DAC may inhibit cancer cell colony formation, migration through EMT (epithelial–mesenchymal transition) process regulation, total DNMT activity, especially in DNMT3a protein expression, and may also regulate tumor suppressor gene SFRP5 expression involved in the Wnt/β-catenin signaling pathway. The combined treatment attenuated ovarian cancer development.

The effect of GnRH antagonist cetrorelix on Wnt signaling members in pubertal and adult mouse ovaries

Wide application of gonadotropin-releasing hormone (GnRH) agonists and antagonists for clinical purposes determines their effects on ovarian signaling pathways. Our study aimed to determine the localization, expression levels of Wnt signaling members in the pubertal and adult mouse ovary and the impact of GnRH antagonist cetrorelix on these signaling members. 0.5 mg/kg of cetrorelix was injected to 3-and 6-week-old mice for 2 weeks. At the end of injection, ovaries from 5 (5Ce)- to 8-week (8Ce)-old mice were embedded in paraffin for immunohistochemistry and homogenized for western blot to compare with control (5C-8C) and sham groups (5S-8S). WNT2 and WNT4 showed higher expression in thecal and stromal cells in adult mouse ovaries and only WNT4 expression was affected by cetrorelix. FZD1 was localized mainly in oocytes of pubertal ovaries and granulosa cells and oocytes of adult ovaries. FZD1 was reduced by cetrorelix in pubertal ovaries. FZD4 was abundantly localized in thecal and stromal cells of all groups and protein level was not affected by cetrorelix. LRP-6 was expressed mainly in oocytes and stromal cells of pubertal, oocytes of adult ovaries and its expression was reduced by cetrorelix in adult ovaries. CTNNB1 intensity in granulosa cells was the lowest in pubertal and the highest in adult ovaries and its expression was decreased by cetrorelix in adult ovaries. Cetrorelix affected the expression of specific members of the Wnt signaling depending on the developmental stage of mice, pointing out its possible interaction with gonadotropins during pubertal and adult stages.

Wnt Signaling in Ovarian Cancer Stemness, EMT, and Therapy Resistance

Ovarian cancers represent the deadliest among gynecologic malignancies and are characterized by a hierarchical structure with cancer stem cells (CSCs) endowed with self-renewal and the capacity to differentiate. The Wnt/β-catenin signaling pathway, known to regulate stemness in a broad spectrum of stem cell niches including the ovary, is thought to play an important role in ovarian cancer. Importantly, Wnt activity was shown to correlate with grade, epithelial to mesenchymal transition, chemotherapy resistance, and poor prognosis in ovarian cancer. This review will discuss the current knowledge of the role of Wnt signaling in ovarian cancer stemness, epithelial to mesenchymal transition (EMT), and therapy resistance. In addition, the alleged role of exosomes in the paracrine activation of Wnt signaling and pre-metastatic niche formation will be reviewed. Finally, novel potential treatment options based on Wnt inhibition will be highlighted.

Wnt Signaling Pathways in Keratinocyte Carcinomas

The skin functions as a barrier between the organism and the surrounding environment. Direct exposure to external stimuli and the accumulation of genetic mutations may lead to abnormal cell growth, irreversible tissue damage and potentially favor skin malignancy. Skin homeostasis is coordinated by an intricate signaling network, and its dysregulation has been implicated in the development of skin cancers. Wnt signaling is one such regulatory pathway orchestrating skin development, homeostasis, and stem cell activation. Aberrant regulation of Wnt signaling cascades not only gives rise to tumor initiation, progression and invasion, but also maintains cancer stem cells which contribute to tumor recurrence. In this review, we summarize recent studies highlighting functional evidence of Wnt-related oncology in keratinocyte carcinomas, as well as discussing preclinical and clinical approaches that target oncogenic Wnt signaling to treat cancers. Our review provides valuable insight into the significance of Wnt signaling for future interventions against keratinocyte carcinomas.

Exome Sequencing Reveals the POLR3H Gene as a Novel Cause of Primary Ovarian Insufficiency

CONTEXT

Primary ovarian insufficiency (POI) is a cause of female infertility. However, the genetic etiology of this disorder remains unknown in most patients with POI.

OBJECTIVE

To investigate the genetic etiology of idiopathic POI.

PATIENTS AND METHODS

We performed whole-exome sequencing of 11 families with idiopathic POI. To gain insights into the potential mechanisms associated with this mutation, we generated two mouse lines via clustered regularly interspaced short palindromic repeats/Cas9 technology.

RESULTS

A pathogenic homozygous missense mutation (c.149A>G; p.Asp50Gly) in the POLR3H gene in two unrelated families was identified. Pathogenic mutations in this subunit have not been associated with human disorders. Loss-of-function Polr3h mutation in mice caused early embryonic lethality. Mice with homozygous point mutation (Polr3hD50G) were viable but showed delayed pubertal development, characterized by late first estrus or preputial separation. The Polr3hD50G female and male mice showed decreased fertility later in life, associated with small litter size and increased time to pregnancy or to impregnate a female. Polr3hD50G mice displayed decreased expression of ovarian Foxo3a and lower numbers of primary follicles.

CONCLUSION

Our manuscript provides a case of POI caused by missense mutation in POLR3H, expanding the knowledge of molecular pathways of the ovarian function and human infertility. Screening of the POLR3H gene may elucidate POI cases without previously identified genetic causes, supporting approaches of genetic counseling.

Morphometric analyses and gene expression related to germ cells, gonadal ridge epithelial-like cells and granulosa cells during development of the bovine fetal ovary

Cells on the surface of the mesonephros give rise to replicating Gonadal Ridge Epithelial-Like (GREL) cells, the first somatic cells of the gonadal ridge. Later germ cells associate with the GREL cells in the ovigerous cords, and the GREL cells subsequently give rise to the granulosa cells in follicles. To examine these events further, 27 bovine fetal ovaries of different gestational ages were collected and prepared for immunohistochemical localisation of collagen type I and Ki67 to identify regions of the ovary and cell proliferation, respectively. The non-stromal cortical areas (collagen-negative) containing GREL cells and germ cells and later in development, the follicles with oocytes and granulosa cells, were analysed morphometrically. Another set of ovaries (n = 17) were collected and the expression of genes associated with germ cell lineages and GREL/granulosa cells were quantitated by RT-PCR. The total volume of non-stromal areas in the cortex increased significantly and progressively with ovarian development, plateauing at the time the surface epithelium developed. However, the proportion of non-stromal areas in the cortex declined significantly and progressively throughout gestation, largely due to a cessation in growth of the non-stroma cells and the continued growth of stroma. The proliferation index in the non-stromal area was very high initially and then declined substantially at the time follicles formed. Thereafter, it remained low. The numerical density of the non-stromal cells was relatively constant throughout ovarian development. The expression levels of a number of genes across gestation either increased (AMH, FSHR, ESR1, INHBA), declined (CYP19A1, ESR2, ALDH1A1, DSG2, OCT4, LGR5) or showed no particular pattern (CCND2, CTNNB1, DAZL, FOXL2, GATA4, IGFBP3, KRT19, NR5A1, RARRES1, VASA, WNT2B). Many of the genes whose expression changed across gestation, were positively or negatively correlated with each other. The relationships between these genes may reflect their roles in the important events such as the transition of ovigerous cords to follicles, oogonia to oocytes or GREL cells to granulosa cells.

Genome-wide differences in DNA methylation changes in caprine ovaries between oestrous and dioestrous phases

Background

DNA methylation plays a vital role in reproduction. Entire genome DNA methylation changes during the oestrous phase (ES) and dioestrous phase (DS) in the ovaries of Guanzhong dairy goats were investigated using bisulphite sequencing to understand the molecular biological mechanisms of these goats’ oestrous cycle.

Results

We discovered distinct genome-wide DNA methylation patterns in ES and DS ovaries. A total of 26,910 differentially methylated regions were upregulated and 21,453 differentially methylated regions were downregulated in the ES samples compared with the DS samples (P-values ≤0.05 and fold change of methylation ratios ≥2). Differentially methylated region analysis showed hypomethylation in the gene body regions and hypermethylation in the joining region between upstream regions and gene bodies. The methylation ratios of the STAR, FGF2, FGF12, BMP5 and SMAD6 genes in the ES samples were lower than those of the DS samples (P-values ≤0.05 and fold change of methylation ratios ≥2). Conversely, the methylation ratios of the EGFR, TGFBR2, IGF2BP1 and MMD2 genes increased in the ES samples compared with the DS samples. In addition, 223 differentially methylated genes were found in the GnRH signalling pathway (KO04912), ovarian steroidogenesis pathway (KO04913), oestrogen signalling pathway (KO04915), oxytocin signalling pathway (KO04921), insulin secretion pathway (KO04911) and MAPK signalling pathway (KO04010).

Conclusions

This study is the first large-scale comparison of the high-resolution DNA methylation landscapes of oestrous and dioestrous ovaries from dairy goats. Previous studies and our investigations have shown that the NR5A2, STAR, FGF2 and BMP5 genes might have potential application value in regulating caprine oestrus.

Electronic supplementary material

The online version of this article (10.1186/s40104-018-0301-x) contains supplementary material, which is available to authorized users.

Dynamic Changes in the Global MicroRNAome and Transcriptome Identify Key Nodes Associated With Ovarian Development in Chickens

The analysis of gene expression patterns during ovarian follicle development will advance our understanding of avian reproductive physiology and make it possible to improve laying performance. To gain insight into the molecular regulation of ovarian development, a systematic profiling of miRNAs and mRNAs at four key stages was conducted, using ovarian tissues from hens at 60 days of age (A), 100 days (B), 140 days-not yet laying (C), and 140 days-laying (D). Comparisons of consecutive stages yielded 73 differentially expressed miRNAs (DEMs) (14 for B vs. A, 8 for C vs. B, and 51 for D vs. C) and 2596 differentially expressed genes (DEGs) (51 for B vs. A, 20 for C vs. B, and 2579 for D vs. C). In addition, 174 DEMs (22 for C vs. A, 74 for D vs. A, and 78 for D vs. B) and 3205 DEGs (118 for C vs. A, 2284 for D vs. A, and 2882 for D vs. B) were identified between nonconsecutive stages. Some DEGs are involved in the Wnt and TGF-beta signaling pathways, which are known to affect ovarian development and ovulation. An integrative analysis of the miRNA and mRNA profiles identified 3166 putative miRNA-mRNA regulatory pairs containing 84 DEMs and 1047 DEGs. Functional annotation of the networks provides strong evidence that the miRNA regulatory networks may play vital roles in ovarian development and ovulation. Ten DEMs and 10 genes were validated by real-time quantitative PCR. The candidate miRNA-mRNA pairs gga-miR-200a-3p-SFRP4, gga-miR-101-3p-BMP5, gga-miR-32-5p-FZD4, and gga-miR-458b-5p-CTNNB1 potentially associated with ovarian development.

Expression Analysis of ACSL5 and Wnt2B in Human Congenital Pulmonary Airway Malformations

BACKGROUND

The objective of this study was to determine acyl-CoA synthetase 5 (ACSL5) and Wnt2B expression patterns in human congenital pulmonary airway malformations (CPAMs) and to identify the possible roles of ACSL5 and Wnt2B in the pathogenesis of CPAM.

METHODS

Expression of ACSL5 and Wnt2B was evaluated by immunohistochemical staining, Western blotting, and quantitative real-time polymerase chain reaction, which were performed on surgical specimens of CPAM and adjacent normal lung tissues as controls.

RESULTS

Immunohistochemistry revealed that ACSL5 and Wnt2B immunopositive cells were predominantly detected in the mesenchymal cell nucleus, and there were lower expressions of ACSL5 and Wnt2B immunopositive cells in CPAM tissues than those in adjacent normal lung tissues. Western blotting and quantitative real-time polymerase chain reaction showed that ACSL5 and Wnt2B protein and mRNA expressions were significantly decreased in CPAM tissues as compared to the adjacent normal lung tissues (P < 0.05). In addition, there was a reduced level of ACSL5 relative to that of Wnt2B.

CONCLUSIONS

The decreased ACSL5 and Wnt2B expressions correlated with aberrations in pulmonary development and in the pathogenesis of CPAM, so downregulation of ACSL5 and Wnt2B could play an important role in the development of bronchial-alveolar structures in CPAM.

ASAS-SSR Triennial Reproduction Symposium: Looking Back and Moving Forward-How Reproductive Physiology has Evolved: WNTs role in bovine folliculogenesis and estrogen production

Appreciation of mechanisms that affect steroidogenesis is critical to identifying compromising signals that may decrease reproductive efficiency. Follicle maturation and steroidogenesis requires coordinated actions from the pituitary gonadotropins and local ovarian signaling molecules. β-Catenin (CTNNB1), the lynchpin molecule of canonical wingless-type mouse mammary tumor virus integration site (WNT) signaling, is required for maximal gonadotropin stimulation of steroid production from granulosa (GC) and luteal cells. WNTs are locally secreted glycoproteins involved in ovarian development and folliculogenesis. In cultured bovine GC, WNT2 and AKT mRNAs and CTNNB1 protein increase after FSH stimulation. Likewise, CTNNB1 protein is greater in large antral follicles with high intrafollicular estradiol concentrations, suggesting the hormonal milieu responsible for increased estradiol content modulates CTNNB1 accumulation. In addition, concurrent treatment of FSH and WNT3A in GC results in reduced steroidogenic enzymes and ovarian differentiation factors. It is likely that FSH regulation of WNT signaling establishes a negative feedback loop to ensure CTNNB1 remains controlled. To explore the mechanism resulting in this inhibitory effect, AKT pathway modulators were utilized and unveiled a requirement for AKT activity in FSH-mediated CTNNB1 accumulation. Cells treated with FSH, IGF-1, and IGF-1 + FSH had increased CTNNB1 protein accumulation compared with controls. Similarly, estradiol medium concentrations increased in treated cells compared with non-treated controls, while co-treatment of FSH and IGF-1 with the AKT inhibitor LY294002 reduced CTNNB1 and estradiol production. Subsequent studies evaluated whether FSH regulation of CTNNB1 occurs through a specific phosphorylation event. In bovine GC, phosphorylation of CTNNB1 at Ser-552 was demonstrated in FSH-treated cells, whereas IGF-1 treatment did not phosphorylate CTNNB1 Ser-552. Data indicate that in cattle phosphorylation on CTNNB1 Ser-552 is a protein kinase A (PKA) dependent, protein kinase B (AKT) independent event. Data suggest that CTNNB1 regulated by AKT is a fundamental component of FSH-induced estrogen production. However, AKT's role in estradiol synthesis does not appear to be through phosphorylation of CTNNB1 Ser-552. The complex interplay between FSH and ovarian WNT/CTNNB1 signaling is key to regulation of follicle maturation and steroidogenesis.

Temporal expression pattern of genes during the period of sex differentiation in human embryonic gonads

The precise timing and sequence of changes in expression of key genes and proteins during human sex-differentiation and onset of steroidogenesis was evaluated by whole-genome expression in 67 first trimester human embryonic and fetal ovaries and testis and confirmed by qPCR and immunohistochemistry (IHC). SRY/SOX9 expression initiated in testis around day 40 pc, followed by initiation of AMH and steroidogenic genes required for androgen production at day 53 pc. In ovaries, gene expression of RSPO1, LIN28, FOXL2, WNT2B, and ETV5, were significantly higher than in testis, whereas GLI1 was significantly higher in testis than ovaries. Gene expression was confirmed by IHC for GAGE, SOX9, AMH, CYP17A1, LIN28, WNT2B, ETV5 and GLI1. Gene expression was not associated with the maternal smoking habits. Collectively, a precise temporal determination of changes in expression of key genes involved in human sex-differentiation is defined, with identification of new genes of potential importance.

Identification and comparative analysis of the ovarian microRNAs of prolific and non-prolific goats during the follicular phase using high-throughput sequencing

The kidding rate is one of the most important economic traits for goat production, but the genetic mechanism that is associated with ovulation rate is poorly understood. Recently, increasing evidence has suggested that microRNAs (miRNAs) influence ovarian biological processes. The present study provides the first comparison of the ovarian miRNAs of prolific Jintang black goats (JTGs) and non-prolific Tibetan goats (TBGs) during the follicular phase using RNA-Seq technology. We generated 11.19 million (M) and 11.34 M clean reads from the TBG and JTG libraries, respectively, from which a total of 389 known miRNAs were identified and 142 novel miRNAs were predicted. A total of 191 miRNAs were differentially expressed between the two breeds. Among the 10 most abundant miRNAs, miR-21-5p was defined as differentially expressed miRNA with a higher level in the JTG library than in the TBG library, but the other miRNAs were not different between the breeds. The predicted miRNA-targeted genes were further analyzed by Gene Ontology and KEGG pathway analyses. The results revealed that miR-21, miR-99a, miRNA-143, let-7f, miR-493 and miR-200b may affect follicular development. These findings will increase the current understanding of the role of ovarian miRNAs in the regulation of ovulation rate in goats.

Stable reference genes in granulosa cells of bovine dominant follicles during follicular growth, FSH stimulation and maternal aging

The aim of the present study was to determine a set of reference genes in granulosa cells of dominant follicles that are suitable for relative gene expression analyses during maternal and follicular aging. Granulosa cells of growing and preovulatory dominant follicles were collected from aged and young cows (maternal aging study) and from FSH-stimulated follicles developing under different durations of FSH treatment (follicular aging study). The mRNA levels of the two commonly used reference genes (GAPDH, ACTB) and four novel genes (UBE2D2, EIF2B2, SF3A1, RNF20) were analysed using cycle threshold values. Results revealed that mRNA levels of GAPDH, ACTB, EIF2B2, RNF20, SF3A1 and UBE2D2 were similar (P>0.05) between dominant follicle type, age and among follicles obtained after FSH-stimulation, but differed (P=0.005) due to mRNA processing (i.e. with versus without amplification). The stability of reference genes was analysed using GeNorm, DeltaCT and NormFinder programs and comprehensive ranking order was determined using RefFinder. The mRNA levels of GAPDH and ACTB were less stable than those of UBE2D2 and EIF2B2. The geometric mean of multiple genes (UBE2D2, EIF2B2, GAPDH and SF3A1) is a more appropriate reference control than the use of a single reference gene to compare relative gene expression among dominant and FSH-stimulated follicles during maternal and/or follicular aging studies.

Transcriptomic responses to environmental temperature by turtles with temperature-dependent and genotypic sex determination assessed by RNAseq inform the genetic architecture of embryonic gonadal development

Vertebrate sexual fate is decided primarily by the individual's genotype (GSD), by the environmental temperature during development (TSD), or both. Turtles exhibit TSD and GSD, making them ideal to study the evolution of sex determination. Here we analyze temperature-specific gonadal transcriptomes (RNA-sequencing validated by qPCR) of painted turtles (Chrysemys picta TSD) before and during the thermosensitive period, and at equivalent stages in soft-shell turtles (Apalone spinifera-GSD), to test whether TSD's and GSD's transcriptional circuitry is identical but deployed differently between mechanisms. Our data show that most elements of the mammalian urogenital network are active during turtle gonadogenesis, but their transcription is generally more thermoresponsive in TSD than GSD, and concordant with their sex-specific function in mammals [e.g., upregulation of Amh, Ar, Esr1, Fog2, Gata4, Igf1r, Insr, and Lhx9 at male-producing temperature, and of β-catenin, Foxl2, Aromatase (Cyp19a1), Fst, Nf-kb, Crabp2 at female-producing temperature in Chrysemys]. Notably, antagonistic elements in gonadogenesis (e.g., β-catenin and Insr) were thermosensitive only in TSD early-embryos. Cirbp showed warm-temperature upregulation in both turtles disputing its purported key TSD role. Genes that may convert thermal inputs into sex-specific development (e.g., signaling and hormonal pathways, RNA-binding and heat-shock) were differentially regulated. Jak-Stat, Nf-κB, retinoic-acid, Wnt, and Mapk-signaling (not Akt and Ras-signaling) potentially mediate TSD thermosensitivity. Numerous species-specific ncRNAs (including Xist) were differentially-expressed, mostly upregulated at colder temperatures, as were unannotated loci that constitute novel TSD candidates. Cirbp showed warm-temperature upregulation in both turtles. Consistent transcription between turtles and alligator revealed putatively-critical reptilian TSD elements for male (Sf1, Amh, Amhr2) and female (Crabp2 and Hspb1) gonadogenesis. In conclusion, while preliminary, our data helps illuminate the regulation and evolution of vertebrate sex determination, and contribute genomic resources to guide further research into this fundamental biological process.

Identification of Polycystic Ovary Syndrome (PCOS) Specific Genes in Cumulus and Mural Granulosa Cells

Polycystic ovary syndrome (PCOS) is a metabolic and endocrine disorder which affects women of reproductive age with prevalence of 8–18%. The oocyte within the follicle is surrounded by cumulus cells (CCs), which connect with mural granulosa cells (MGCs) that are responsible for secreting steroid hormones. The main aim of this study is comparing gene expression profiles of MGCs and CCs in PCOS and control samples to identify PCOS-specific differentially expressed genes (DEGs). In this study, two microarray databases were searched for mRNA expression microarray studies performed with CCs and MGCs obtained from PCOS patients and control samples. Three independent studies were selected to be integrated with naive meta-analysis since raw meta-data from these studies were found to be highly correlated. DEGs in these somatic cells were identified for PCOS and control groups. This study enabled us to reveal dysregulation in MAPK (mitogen activated protein kinase), insulin and Wnt signaling pathways between CCs and MGCs in PCOS. The meta-analysis results together with qRT-PCR validations provide evidence that molecular signaling is dysregulated through MGCs and CCs in PCOS, which is important for follicle and oocyte maturation and may contribute to the pathogenesis of the syndrome.

Wnt2 complements Wnt/β-catenin signaling in colorectal cancer

Wnt2 is implicated in various human cancers. However, it remains unknown how Wnt2 is upregulated in human cancer and contributes to tumorigenesis. Here we found that Wnt2 is highly expressed in colorectal cancer (CRC) cells. In addition to co-expression of Wnt2 with Wnt/β-catenin target genes in CRC, knockdown or knockout of Wnt2 significantly downregulates Wnt/β-catenin target gene expression in CRC cells. Importantly, depletion or ablation of endogenous Wnt2 inhibits CRC cell proliferation. Similarly, neutralizing secreted Wnt2 reduces Wnt target gene expression and suppresses CRC cell proliferation. Conversely, Wnt2 increases cell proliferation of intestinal epithelial cells. Intriguingly, WNT2 expression is transcriptionally silenced by EZH2-mediated H3K27me3 histone modification in non-CRC cells, However, WNT2 expression is de-repressed by the loss of PRC2's promoter occupancy in CRC cells. Our results reveal the unexpected roles of Wnt2 in complementing Wnt/β-catenin signaling for CRC cell proliferation.

Phylogenetic and Evolutionary Analyses of the Frizzled Gene Family in Common Carp (Cyprinus carpio) Provide Insights into Gene Expansion from Whole-Genome Duplications

In humans, the frizzled (FZD) gene family encodes 10 homologous proteins that commonly localize to the plasma membrane. Besides being associated with three main signaling pathways for cell development, most FZDs have different physiological effects and are major determinants in the development process of vertebrates and. Here, we identified and annotated the FZD genes in the whole-genome of common carp (Cyprinus carpio), a teleost fish, and determined their phylogenetic relationships to FZDs in other vertebrates. Our analyses revealed extensive gene duplications in the common carp that have led to the 26 FZD genes that we detected in the common carp genome. All 26 FZD genes were assigned orthology to the 10 FZD genes of on-land vertebrates, with none of genes being specific to the fish lineage. We postulated that the expansion of the FZD gene family in common carp was the result of an additional whole genome duplication event and that the FZD gene family in other teleosts has been lost in their evolution history with the reason that the functions of genes are redundant and conservation. Through the expression profiling of FZD genes in common carp, we speculate that the ancestral gene was likely capable of performing all functions and was expressed broadly, while some descendant duplicate genes only performed partial functions and were specifically expressed at certain stages of development.

WNT5a is required for normal ovarian follicle development and antagonizes gonadotropin responsiveness in granulosa cells by suppressing canonical WNT signaling

Whereas the roles of the canonical wingless-type MMTV (mouse mammary tumor virus) integration site family (WNT) signaling pathway in the regulation of ovarian follicle growth and steroidogenesis are now established, noncanonical WNT signaling in the ovary has been largely overlooked. Noncanonical WNTs, including WNT5a and WNT11, are expressed in granulosa cells (GCs) and are differentially regulated throughout follicle development, but their physiologic roles remain unknown. Using conditional gene targeting, we found that GC-specific inactivation ofWnt5a(but notWnt11) results in the female subfertility associated with increased follicular atresia and decreased rates of ovulation. Microarray analyses have revealed that WNT5a acts to down-regulate the expression of FSH-responsive genesin vitro, and corresponding increases in the expression of these genes have been found in the GCs of conditional knockout mice. Unexpectedly, we found that WNT5a regulates its target genes not by signalingviathe WNT/Ca(2+)or planar cell polarity pathways, but rather by inhibiting the canonical pathway, causing both β-catenin (CTNNB1) and cAMP responsive element binding (CREB) protein levels to decreaseviaa glycogen synthase kinase-3β-dependent mechanism. We further found that WNT5a prevents follicle-stimulating hormone and luteinizing protein from up-regulating the CTNNB1 and CREB proteins and their target genes, indicating that WNT5a functions as a physiologic inhibitor of gonadotropin signaling. Together, these findings identify WNT5a as a key regulator of follicle development and gonadotropin responsiveness.-Abedini, A., Zamberlam, G., Lapointe, E., Tourigny, C., Boyer, A., Paquet, M., Hayashi, K., Honda, H., Kikuchi, A., Price, C., Boerboom, D. WNT5a is required for normal ovarian follicle development and antagonizes gonadotropin responsiveness in granulosa cells by suppressing canonical WNT signaling.

Ovary and fimbrial stem cells: biology, niche and cancer origins

The mammalian ovary is covered by a single-layered epithelium that undergoes rupture and remodelling following each ovulation. Although resident stem cells are presumed to be crucial for this cyclic regeneration, their identity and mode of action have been elusive. Surrogate stemness assays and in vivo fate-mapping studies using recently discovered stem cell markers have identified stem cell pools in the ovary and fimbria that ensure epithelial homeostasis. Recent findings provide insights into intrinsic mechanisms and local extrinsic cues that govern the function of ovarian and fimbrial stem cells. These discoveries have advanced our understanding of stem cell biology in the ovary and fimbria, and lay the foundations for evaluating the contribution of resident stem cells to the initiation and progression of human epithelial ovarian cancer.

The role of WNT signaling in adult ovarian folliculogenesis

Wingless-type mouse mammary tumor virus integration site (WNT) signaling molecules are locally secreted glycoproteins that play important role in regulation of ovarian follicle maturation and steroid production. Components of the WNT signaling pathway have been demonstrated to impact reproductive functions, including embryonic development of the sex organs and regulation of follicle maturation controlling steroidogenesis in the postnatal ovary. Emerging evidence underscores the complexity of WNT signaling molecules in regulation of dynamic changes that occur in the ovary during the reproductive cycle. While disruption in the WNT signaling cascade has been recognized to have deleterious consequences to normal sexual development, more recent studies are beginning to highlight the importance of these molecules in adult ovarian function related to follicle development, corpus luteum formation, steroid production and fertility. Hormonal regulation of WNT genes and expression of members of the WNT signaling network, including WNT ligands, frizzled receptors, and downstream signaling components that are expressed in the postnatal ovary at distinct stages of the estrous cycle suggest a crucial role in normal ovarian function. Similarly, FSH stimulation of T-cell factor-dependent gene expression requires input from β-catenin, a lynchpin molecule in canonical WNT signaling, further indicating β-catenin participation in regulation of follicle maturation. This review will focus on the multiple functions of WNT signaling in folliculogenesis in the adult ovary.

ARID3B Directly Regulates Ovarian Cancer Promoting Genes

The DNA-binding protein AT-Rich Interactive Domain 3B (ARID3B) is elevated in ovarian cancer and increases tumor growth in a xenograft model of ovarian cancer. However, relatively little is known about ARID3B's function. In this study we perform the first genome wide screen for ARID3B direct target genes and ARID3B regulated pathways. We identified and confirmed numerous ARID3B target genes by chromatin immunoprecipitation (ChIP) followed by microarray and quantitative RT-PCR. Using motif-finding algorithms, we characterized a binding site for ARID3B, which is similar to the previously known site for the ARID3B paralogue ARID3A. Functionality of this predicted site was demonstrated by ChIP analysis. We next demonstrated that ARID3B induces expression of its targets in ovarian cancer cell lines. We validated that ARID3B binds to an epidermal growth factor receptor (EGFR) enhancer and increases mRNA expression. ARID3B also binds to the promoter of Wnt5A and its receptor FZD5. FZD5 is highly expressed in ovarian cancer cell lines, and is upregulated by exogenous ARID3B. Both ARID3B and FZD5 expression increase adhesion to extracellular matrix (ECM) components including collagen IV, fibronectin and vitronectin. ARID3B-increased adhesion to collagens II and IV require FZD5. This study directly demonstrates that ARID3B binds target genes in a sequence-specific manner, resulting in increased gene expression. Furthermore, our data indicate that ARID3B regulation of direct target genes in the Wnt pathway promotes adhesion of ovarian cancer cells.

Non-canonical WNT5A is a potential regulator of granulosa cell function in cattle

The WNT family has been implicated in follicular development in rodents, however, the role of WNTs in the follicle of monovulatory species is poorly understood. The objective of this study was to determine the potential roles of WNTs in bovine granulosa cell function. Cells cultured in serum-free medium expressed mRNA encoding WNT2B, WNT5B and WNT5A. Levels of WNT5A, but not of WNT2B or WNT5B mRNA, were down-regulated by FSH. Addition of WNT5A to cultured cells suppressed FSH-stimulated estradiol and progesterone secretion, and levels of mRNA encoding the steroidogenic enzymes CYP19A1, CYP11A1 and the FSH receptor, but had no effect on cell proliferation or apoptosis. Immunoblot experiments showed that WNT5A reduced activation of CTNNB1 and stimulated phosphorylation of MAPK8 and JUN proteins. We conclude that WNT5A is a negative regulator of FSH-stimulated granulosa cell steroidogenesis, and that it acts by suppressing canonical WNT signaling activity and inducing the non-canonical MAPK8/JUN pathway.

Cytokine (IL16) and tyrphostin actions on ovarian primordial follicle development

An ovarian follicle is composed of an oocyte and surrounding theca and granulosa cells. Oocytes are stored in an arrested state within primordial follicles until they are signaled to re-initiate development by undergoing primordial-to-primary follicle transition. Previous gene bionetwork analyses of primordial follicle development identified a number of critical cytokine signaling pathways and genes potentially involved in the process. In the current study, candidate regulatory genes and pathways from the gene network analyses were tested for their effects on the formation of primordial follicles (follicle assembly) and on primordial follicle transition using whole ovary organ culture experiments. Observations indicate that the tyrphostin inhibitor (E)-2-benzylidene-3-(cyclohexylamino)-2,3-dihydro-1H-inden-1-one increased follicle assembly significantly, supporting a role for the MAPK signaling pathway in follicle assembly. The cytokine interleukin 16 (IL16) promotes primordial-to-primary follicle transition as compared with the controls, where as Delta-like ligand 4 (DLL4) and WNT-3A treatments have no effect. Immunohistochemical experiments demonstrated the localization of both the cytokine IL16 and its receptor CD4 in the granulosa cells surrounding each oocyte within the ovarian follicle. The tyrphostin LDN193189 (LDN) is an inhibitor of the bone morphogenic protein receptor 1 within the TGFB signaling pathway and was found to promote the primordial-to-primary follicle transition. Observations support the importance of cytokines (i.e., IL16) and cytokine signaling pathways in the regulation of early follicle development. Insights into regulatory factors affecting early primordial follicle development are provided that may associate with ovarian disease and translate to improved therapy in the future.