Inhibitor of differentiation (Id) genes are expressed in the steroidogenic cells of the ovine ovary and are differentially regulated by members of the transforming growth factor-beta family

AMH protects the ovary from doxorubicin by regulating cell fate and the response to DNA damage

Anti-Müllerian hormone (AMH) protects the ovarian reserve from chemotherapy, and this effect is most pronounced with Doxorubicin (DOX). However, the mechanisms of DOX toxicity and AMH rescue in the ovary remain unclear. Herein, we characterize these mechanisms in various ovarian cell types using scRNAseq. In the mesenchyme, DOX activates the intrinsic apoptotic signaling pathway through p53 class mediators, particularly affecting theca progenitors, while co-treament with AMH halts theca differentiation and reduces apoptotic gene expression. In preantral granulosa cells, DOX upregulates the cell cycle inhibitor Cdkn1a and dysregulates Wnt signaling, which are ameliorated by AMH co-treatment. Finally, in follicles, AMH induces Id3 , a protein involved in DNA repair, which is necessary to prevent the accumulation of DNA lesions marked by γ-H2AX in granulosa cells. Altogether this study characterizes cell, and follicle stage-specific mechanisms of AMH protection of the ovary, offering promising new avenues for fertility preservation in cancer patients undergoing chemotherapy.

Highlights

Doxorubicin treatment induces DNA damage that activates the p53 pathway in stromal and follicular cells of the ovary.AMH inhibits the proliferation and differentiation of theca and granulosa cells and promotes follicle survival following Doxorubicin insult.AMH treatment mitigates Doxorubicin-induced DNA damage in the ovary by preventing the accumulation of γ-H2AX-positive unresolved foci, through increased expression of ID3, a protein involved in DNA repair.

Identification of ID1 and miR-150 interaction and effects on proliferation and apoptosis in ovine granulosa cells

Granulosa cells (GCs) proliferation and apoptosis play a significantly role in follicular development and atresia. ID1 and miR-150 are involved in cell apoptosis and follicular atresia, but the interaction and function of ID1 and miR-150 in GCs are unclear. This study focuses on ID1 and miR-150 in terms of the interaction and effects on proliferation and apoptosis in ovine granulosa cells. Our findings revealed that ID1 decreased the promoter activity and expression level of oar-miR-150. However, the expression of ID1 was downregulated by miR-150, and ID1 was identified as a target gene of oar-miR-150. miR-150 mimic inhibited proliferation and upregulated apoptosis rate in ovine GCs, while the results of miR-150 inhibitor were opposite. Overexpression of ID1 significantly inhibited ovine GCs proliferation and cell cycle-related genes (CDK1, CDK2, CDK4, CCND2, CDC20, and PCNA) expression, whereas knockdown of ID1 promoted cell proliferation and those genes expression. Overexpression of ID1 significantly downregulated mitochondrial membrane potential and Bcl-2 expression in ovine GCs, and upregulated the expression of pro-apoptosis genes Bax, Caspase-3, and Caspase-9, whereas the results of ID1 knockdown were reversed. Collectively, these findings indicate the interaction and the vital role of ID1 and miR-150 on proliferation and apoptosis in ovine granulosa cells, which may suggest a novel target for ovine follicular development and atresia.

Development of an acute ovine model of polycystic ovaries to assess the effect of ovarian denervation

Introduction

Polycystic ovary syndrome (PCOS) seems to be associated with increased ovarian sympathetic nerve activity and in rodent models of PCOS reducing the sympathetic drive to the ovary, through denervation or neuromodulation, improves ovulation rate. We hypothesised that sympathetic nerves work with gonadotropins to promote development and survival of small antral follicles to develop a polycystic ovary phenotype.

Methods

Using a clinically realistic ovine model we showed a rich sympathetic innervation to the normal ovary and reinnervation after ovarian transplantation. Using needlepoint diathermy to the nerve plexus in the ovarian vascular pedicle we were able to denervate the ovary resulting in reduced intraovarian noradrenaline and tyrosine hydroxylase immunostained sympathetic nerves. We developed an acute polycystic ovary (PCO) model using gonadotrophin releasing hormone (GnRH) agonist followed infusion of follicle stimulating hormone (FSH) with increased pulsatile luteinising hormone (LH). This resulted in increased numbers of smaller antral follicles in the ovary when compared to FSH infusion suggesting a polycystic ovary.

Results

Denervation had no effect of the survival or numbers of follicles in the acute PCO model and did not impact on ovulation, follicular and luteal hormone profiles in a normal cycle.

Discussion

Although the ovary is richly inervated we did not find evidence for a role of sympathetic nerves in ovarian function or small follicle growth and survival.

ID3 regulates progesterone synthesis in bovine cumulus cells through modulation of mitochondrial function

DNA binding inhibitory factor 3 (ID3) has been shown to have a key role in maintaining proliferation and differentiation. It has been suggested that ID3 may also affect mammalian ovarian function. However, the specific roles and mechanisms are unclear. In this study, the expression level of ID3 in cumulus cells (CCs) was inhibited by siRNA, and the downstream regulatory network of ID3 was uncovered by high-throughput sequencing. The effects of ID3 inhibition on mitochondrial function, progesterone synthesis, and oocyte maturation were further explored. The GO and KEGG analysis results showed that after ID3 inhibition, differentially expressed genes, including StAR, CYP11A1, and HSD3B1, were involved in cholesterol-related processes and progesterone-mediated oocyte maturation. Apoptosis in CC was increased, while the phosphorylation level of ERK1/2 was inhibited. During this process, mitochondrial dynamics and function were disrupted. In addition, the first polar body extrusion rate, ATP production and antioxidation capacity were reduced, which suggested that ID3 inhibition led to poor oocyte maturation and quality. The results will provide a new basis for understanding the biological roles of ID3 as well as cumulus cells.

An integrated transcriptome and microbial community analysis reveals potential mechanisms for increased immune responses when replacing silybum marianum meal with soybean meal in growing lambs

Silybum marianum meal is a by-product that remains silymarin complex and is perceived as a potential-protein source. The potential and its mechanism of silybum marianum meal as a protein supplement in ruminants were evaluated by testing the growth performance, biochemical parameters, cytokine levels, gut transcriptome and microbial community profiles. Forty-two male Hulunbeier growing lambs (aged about 3-month-old; averaged body weight of 21.55 kg) were randomly divided into the CON (with 10% soybean meal) and SIL groups (with 10% silybum marianum meal). There was no significant difference in growth performance, feed intakes, or serum biochemical parameters between CON and SIL. The serum levels of IL-1β, TNF-α, TGF-β, HGF, and VEGF were all increased (p < 0.05) in the SIL group as compared with the CON group. Transcriptome gene set enrichment analysis (GSEA) revealed that the core genes in the rumen from SIL group were enriched with fructose and mannose metabolism, while the core genes in the ileum were enriched for three biological process, including digestive tract development, positive regulation of MAPK cascade, and regulation of I-kappaB kinase/NF-kappaB signaling. The 16S rDNA results showed that the relative abundance of Bacteroidetes, Firmicutes, Synergistetes, and Verrucomicrobia in the rumen from SIL group was significantly higher than that in CON group (p < 0.05), whereas Proteobacteria was significantly lower than that in CON group (p < 0.05). The LEfSe analysis showed that the genera Pyramidobacter, Saccharofermentans, Anaerovibrio, Oscillibacter and Barnesiella were enriched in the rumen from SIL group, whereas Sharpea was enriched in the CON group (LDA > 2). In the ileum, there were no significant differences in the phylum-level classification of microbes observed. At the genus level, the relative abundances of Bifidobacterium and Ruminococcus in the ileum from SIL group were significantly higher than that in the CON group (p < 0.05), whereas the relative abundance of Clostridium_XI was lower (p < 0.05). Correlation analysis showed that Clostridium_XI was negatively correlated with VEGF, TGF-β, TNF-α and HGF (p < 0.05). Core genes BMP4 and CD4 were negatively correlated with Clostridium_XI (p < 0.05). Our results indicated that supplementing silybum marianum meal as a replacement for soybean meal resulted in increased cytokines production without affecting growth performance in growing lambs, and the enrichment of immune-related genes and altered microbial community in the ileum were contributed to the increased immune responses.

Identification and characterization of unique and common lncRNAs and mRNAs in the pituitary, ovary, and uterus of Hu sheep with different prolificacy

LncRNAs are regarded as regulators in various animal reproductive physiological processes. However, the regulation of lncRNAs in the reproductive organ development of Hu sheep with different prolificacy remains unknown. Herein, numerous tissue-unique and -common differentially expressed lncRNAs (DELs) and differentially expressed genes (DEGs), and fecundity-unique DELs and DEGs were identified among different comparison groups at horizontal and vertical levels. Moreover, the tissue-unique and -common, and fecundity-unique female reproduction-associated DEGs and DELs were screened, and the interaction networks were constructed. Furthermore, MSTRG.43442.1 was mainly present in the cytoplasm of tested cells. The key genes ADAMTS1 and DCN were mainly localized in the granulosa cells, pituitary cells and/or endometrial epithelial cells of ovary, pituitary and/or uterus. Overall, this study identified large numbers of unique and common DELs and DEGs in the female reproductive organs of Hu sheep with different prolificacy and provided new insights into understanding the regulation of Hu sheep fecundity.

Single-Cell Transcriptomics Analysis of Human Small Antral Follicles

Human ovarian folliculogenesis is a highly regulated and complex process. Characterization of follicular cell signatures during this dynamic process is important to understand follicle fate (to grow, become dominant, or undergo atresia). The transcriptional signature of human oocytes and granulosa cells (GCs) in early-growing and ovulatory follicles have been previously described; however, that of oocytes with surrounding GCs in small antral follicles have not been studied yet. Here, we have generated a unique dataset of single-cell transcriptomics (SmartSeq2) consisting of the oocyte with surrounding GCs from several individual (non-dominant) small antral follicles isolated from adult human ovaries. We have identified two main types of (healthy) follicles, with a distinct oocyte and GC signature. Using the CellphoneDB algorithm, we then investigated the bi-directional ligand–receptor interactions regarding the transforming growth factor-β (TGFβ)/bone morphogenetic protein (BMP), wingless-type (MMTV)-integration site (WNT), NOTCH, and receptor tyrosine kinases (RTK) signaling pathways between oocyte and GCs within each antral follicle type. Our work not only revealed the diversity of small antral follicles, but also contributes to fill the gap in mapping the molecular landscape of human folliculogenesis and oogenesis.

Milk lactoperoxidase decreases ID1 and ID3 expression in human oral squamous cell carcinoma cell lines

Milk consumption may modify the risk of squamous cell carcinoma. The role of milk to modulate the gene expression in oral squamous cell carcinoma cells has not been investigated so far. Here, HSC2 oral squamous carcinoma cells were exposed to an aqueous fraction of human milk and a whole-genome array was performed. Among the genes that were significantly reduced by human and cow milk were the DNA-binding protein inhibitor 1 (ID1), ID3 and Distal-Less Homeobox 2 (DLX2) in HSC2 cells. Also, in TR146 oral squamous carcinoma cells, there was a tendency towards a decreased gene expression. Upon size fractionation, lactoperoxidase but not lactoferrin and osteopontin was identified to reduce ID1 and ID3 in HSC2 cells. Dairy products and hypoallergenic infant formula failed to decrease the respective genes. These data suggest that milk can reduce the expression of transcription factors in oral squamous carcinoma cells.

Genes regulating hormone stimulus and response to protein signaling revealed differential expression pattern during porcine oocyte in vitro maturation, confirmed by lipid concentration

Genes influencing oocyte maturation may be valuable for predicting their developmental potential, as well as discerning the mechanistic pathways regulating oocyte development. In the presented research microarray gene expression analysis of immature and in vitro matured porcine oocytes was performed. Two groups of oocytes were compared in the study: before (3 × n = 50) and after in vitro maturation (3 × n = 50). The selection of viable oocytes was performed using the brilliant cresyl blue (BCB) test. Furthermore, microarrays and RT-qPCR was used to analyze the transcriptome of the oocytes before and after IVM. The study focused on the genes undergoing differential expression in two gene-ontology groups: “Cellular response to hormone stimulus” and “Cellular response to unfolded protein”, which contain genes that may directly or indirectly be involved in signal transduction during oocyte maturation. Examination of all the genes of interest showed a lower level of their expression after IVM. From the total number of genes in these gene ontologies ten of the highest change in expression were identified: FOS, ID2, BTG2, CYR61, ESR1, AR, TACR3, CCND2, EGR2 and TGFBR3. The successful maturation of the oocytes was additionally confirmed with the use of lipid droplet assay. The genes were briefly described and related to the literature sources, to investigate their potential roles in the process of oocyte maturation. The results of the study may serve as a basic molecular reference for further research aimed at improving the methods of oocyte in vitro maturation, which plays an important role in the procedures of assisted reproduction.

Non-canonical cyclic AMP SMAD1/5/8 signalling in human granulosa cells

Development of mammalian ovarian follicles is promoted by the combined action of endocrine cues and paracrine factors. Follicle stimulating hormone (FSH), through the action of cAMP drives follicular growth and development. The oocyte secretes powerful growth factors such as bone morphogenetic protein 15 (BMP15) to regulate granulosa cell proliferation, metabolism, steroidogenesis and differentiation through the activation of SMAD1/5/8. This study investigated the role of the cAMP signalling pathway on SMAD1/5/8 action in human granulosa cells. Cyclic AMP enhanced BMP15-induction of a SMAD1/5/8-specific BRE reporter. Moreover, in the absence of BMP ligand, cAMP also activated SMAD1/5/8-induced BRE activity. Cyclic AMP increased canonical downstream targets of BMP signalling such as inhibitor of differentiation (ID) mRNA expression. The observed effects were not mediated by secretion of BMPs as cAMP did not promote BMP ligand mRNA expression and a BMP extracellular antagonist, the BMP type II receptor ectodomain, did not affect cAMP-induced ID mRNA expression. Finally, the ERK1/2 pathway was shown to be required for the maintenance of cAMP-induced SMAD1/5/8 activity. Together our results suggest a novel and non-canonical pathway for cAMP signalling in human granulosa cells. Cyclic AMP appears to promote SMAD1/5/8 pathway activity intracellularly and has the ability to activate canonical SMAD1/5/8 downstream targets. Our results add another layer of complexity to the interactions between endocrine signalling and oocyte-secreted BMP ligands during folliculogenesis. Given the importance of both cAMP and SMAD1/5/8 pathways in follicular development, these interactions are likely required for the fine-tuning of oocyte paracrine signalling by endocrine stimuli.

Dullard deficiency causes hemorrhage in the adult ovarian follicles

In mammals, the ovarian follicles are regulated at least in part by bone morphogenetic protein (BMP) family members. Dullard (also known as Ctdnep1) gene encodes a phosphatase that suppresses BMP signaling by inactivating or degrading BMP receptors. Here we report that the Col1a1-Cre-induced Dullard mutant mice displayed hemorrhagic ovarian cysts, with red blood cells accumulated in the follicles, resulting in infertility. Cells expressing Cre driven by Col1a1 2.3-kb promoter and their descendants were found in granulosa cells in the ovary and in Sertoli cells in the testis. DullardmRNA was localized to granulosa cells in the ovary. Genes involved in steroid hormone genesis including Cyp11a1, Hsd3b1 and Star were reduced, whereas expression of Smad6 and Smad7, BMP-inducible inhibitory Smads, was up-regulated in the Dullard mutant ovaries. Tamoxifen-inducible Dullard deletion in the whole body using Rosa26-CreER mice also resulted in hemorrhagic ovarian cysts in 2 weeks, which was rescued by administration of LDN-193189, a chemical inhibitor of BMP receptor kinase, suggesting that the hemorrhage in the Dullard-deficient ovarian follicles might be caused by increased BMP signaling. Thus, we conclude that Dullard is essential for ovarian homeostasis at least in part via suppression of BMP signaling.

Expression of genes associated with BMP signaling pathway in porcine oocytes before and after IVM - a microarray approach

BACKGROUND

The full maturational capability of mammalian oocytes is accompanied by nuclear and cytoplasmic modifications, which are associated with proliferation and differentiation of surrounding cumulus cells. These events are regulated on molecular level by the expression of target genes involved in signal transduction pathways crucial for folliculogenesis and oogenesis. Transforming growth factor beta signaling includes several molecules that are involved in the regulation of oogenesis and embryo growth, including bone morphogenetic protein (BMP). However, the BMP-related gene expression profile in oocytes at different maturational stages requires further investigation.

METHODS

Oocytes were isolated from pubertal crossbred Landrace gilts follicles, selected with a use of BCB staining test and analyzed before and after in vitro maturation. Gene expression profiles were examined using an Affymetrix microarray approach and validated by RT-qPCR. Database for Annotation, Visualization, and Integrated Discovery (DAVID) software was used for the extraction of the genes belonging to a BMP-signaling pathway ontology group.

RESULTS

The assay revealed 12,258 different transcripts in porcine oocytes, among which 379 genes were down-regulated and 40 were up-regulated. The DAVID database indicated a "BMP signaling pathway" ontology group, which was significantly regulated in both groups of oocytes. We discovered five up-regulated genes in oocytes before versus after in vitro maturation (IVM): chordin-like 1 (CHRDL1), follistatin (FST), transforming growth factor-beta receptor-type III (TGFβR3), decapentaplegic homolog 4 (SMAD4), and inhibitor of DNA binding 1 (ID1).

CONCLUSIONS

Increased expression of CHRDL1, FST, TGFβR3, SMAD4, and ID1 transcripts before IVM suggested a subordinate role of the BMP signaling pathway in porcine oocyte maturational competence. Conversely, it is postulated that these genes are involved in early stages of folliculogenesis and oogenesis regulation in pigs, since in oocytes before IVM increased expression was observed.

Does Porcine Oocytes Maturation in Vitro is Regulated by Genes Involved in Transforming Growth Factor Beta Receptor Signaling Pathway?

The oocyte growth and development in follicular environment are substantially accompanied by surrounding somatic cumulus (CCs) and granulosa cells (GCs). During these processes, the mammalian gametes reach full maturational stage and may be further successfully fertilized by single spermatozoon. These unique mechanisms are regulated by expression of clusters of genes and their biochemical signaling pathways.

In this article we described differential expression pattern of transforming growth factor beta (TGFB) gene superfamily in porcine oocytes before and after in vitro maturation (IVM).

We performed Affymetrix® microarray assays to investigate the TGFB-related genes expression profile in porcine immature oocytes and gametes cultured for 44h in vitro.

In results we found 419 different genes, 379 genes with lower expression, and 40 genes characterized by increased RNA profile. Moreover, significant up-regulation of 6 genes belonging to TGFB signaling pathway such as: TGFBR3, SMAD4, FOS, KLF10, ID1, MAP3K1 in immature porcine oocytes (before IVM), was also observed.

It may be suggested that genes involved in TGFB-related signaling pathway are substantially regulated before IVM. Furthermore, these genes may play a significant role during early stages of nuclear and/or cytoplasmic porcine oocytes maturation. The investigated transcripts may be also recommended as the markers of oocytes maturational capability in pigs.

Characterization of Inhibitor of differentiation (Id) proteins in human cornea

Inhibitor of differentiation (Id) proteins are DNA-binding transcription factors involved in cellular proliferation, migration, inflammation, angiogenesis and fibrosis. However, their expression and role in the cornea is unknown. The present study was undertaken to characterize the expression of Id proteins and their interactions with the pro-fibrotic cytokine Transforming Growth Factor β1 (TGFβ1) and anti-fibrotic cytokine, bone morphogenic protein 7 (BMP7) in human cornea. Human donor corneas procured from Eye Bank were used. Id proteins were localized in human corneal sections using immunofluorescence. Primary cultures of human corneal fibroblasts (HCF) were established and treated with either TGFβ1 (5 ng/ml) or BMP7 (10 ng/ml) for 24 h in serum free medium. Expression of Id's in response to TGFβ1, BMP7 and TGFβ1 + BMP7 was analyzed by quantitative real time PCR (qRT-PCR) and western blot analysis. Id1 and Id2 proteins were ubiquitously expressed in the epithelial cells and stromal keratocytes in human cornea. The Id1 was localized to the basal epithelial cells as seen by immunohistochemistry. HCF expressed all known mammalian Id genes (Id1-Id4). In addition, Id1 and Id2 are selectively expressed in HCF. Treatment of human recombinant TGFβ1 (5 ng/ml) to serum-starved HCF showed a significant increase in Id genes (Id1, Id2 and Id4) at 2 h time point compared to BMP7 treatment, which showed time dependent increase in the expression of Id1-Id3 at 24-48 h. Combined treatment with TGFβ1 + BMP7 to HCF showed a significant increase in Id1 transcript and an increasing trend in Id3 and Id4 expression. The results of this study suggest that Id family of genes (Id1-Id4) are localized in the human cornea and expressed in the corneal fibroblasts. Also, Id's were differentially regulated with TGFβ1 and/or BMP7 in a time dependent manner and might serve as a therapeutic target in corneal fibrosis.

Gene expression analysis of pig cumulus-oocyte complexes stimulated in vitro with follicle stimulating hormone or epidermal growth factor-like peptides

BACKGROUND

The gonadotropin-induced resumption of oocyte meiosis in preovulatory follicles is preceded by expression of epidermal growth factor (EGF)-like peptides, amphiregulin (AREG) and epiregulin (EREG), in mural granulosa and cumulus cells. Both the gonadotropins and the EGF-like peptides possess the capacity to stimulate resumption of oocyte meiosis in vitro via activation of a broad signaling network in cumulus cells. To better understand the rapid genomic actions of gonadotropins (FSH) and EGF-like peptides, we analyzed transcriptomes of cumulus cells at 3 h after their stimulation.

METHODS

We hybridized aRNA from cumulus cells to a pig oligonucleotide microarray and compared the transcriptomes of FSH- and AREG/EREG-stimulated cumulus cells with untreated control cells and vice versa. The identified over- and underexpressed genes were subjected to functional genomic analysis according to their molecular and cellular functions. The expression pattern of 50 selected genes with a known or potential function in ovarian development was verified by real-time qRT-PCR.

RESULTS

Both FSH and AREG/EREG increased the expression of genes associated with regulation of cell proliferation, cell migration, blood coagulation and extracellular matrix remodeling. FSH alone induced the expression of genes involved in inflammatory response and in the response to reactive oxygen species. Moreover, FSH stimulated the expression of genes closely related to some ovulatory events either exclusively or significantly more than AREG/EREG (AREG, ADAMTS1, HAS2, TNFAIP6, PLAUR, PLAT, and HSD17B7). In contrast to AREG/EREG, FSH also increased the expression of genes coding for key transcription factors (CEBPB, FOS, ID1/3, and NR5A2), which may contribute to the differing expression profiles of FSH- and AREG/EREG-treated cumulus cells.

CONCLUSIONS

The impact of FSH on cumulus cell gene transcription was higher than the impact of EGF-like factors in terms of the number of cell functions affected as well as the number of over- and underexpressed genes. Both FSH and EGF-like factors overexpressed genes involved in the post-ovulatory switch in steroidogenesis and tissue remodelling. However, FSH was remarkably more efficient in the up-regulation of several specific genes essential for ovulation of matured oocytes and also genes that been reported to play an important role in maturation of cumulus-enclosed oocytes in vitro.

Transcriptomic diversification of developing cumulus and mural granulosa cells in mouse ovarian follicles

Cumulus cells and mural granulosa cells (MGCs) have functionally distinct roles in antral follicles, and comparison of their transcriptomes at a global and systems level can propel future studies on mechanisms underlying their functional diversity. These cells were isolated from small and large antral follicles before and after stimulation of immature mice with gonadotropins, respectively. Both cell types underwent dramatic transcriptomic changes, and differences between them increased with follicular growth. Although cumulus cells of both stages of follicular development are competent to undergo expansion in vitro, they were otherwise remarkably dissimilar with transcriptomic changes quantitatively equivalent to those of MGCs. Gene ontology analysis revealed that cumulus cells of small follicles were enriched in transcripts generally associated with catalytic components of metabolic processes, while those from large follicles were involved in regulation of metabolism, cell differentiation, and adhesion. Contrast of cumulus cells versus MGCs revealed that cumulus cells were enriched in transcripts associated with metabolism and cell proliferation while MGCs were enriched for transcripts involved in cell signaling and differentiation. In vitro and in vivo models were used to test the hypothesis that higher levels of transcripts in cumulus cells versus MGCs is the result of stimulation by oocyte-derived paracrine factors (ODPFs). Surprisingly ∼48% of transcripts higher in cumulus cells than MGCs were not stimulated by ODPFs. Those stimulated by ODPFs were mainly associated with cell division, mRNA processing, or the catalytic pathways of metabolism, while those not stimulated by ODPFs were associated with regulatory processes such as signaling, transcription, phosphorylation, or the regulation of metabolism.

BMP signaling is required for cell cleavage in preimplantation-mouse embryos

The mechanisms regulating cell division during development of the mouse pre-implantation embryo are poorly understood. We have investigated whether bone morphogenetic protein (BMP) signaling is involved in controlling cell cycle during mouse pre-implantation development. We mapped and quantitated the dynamic activities of BMP signaling through high-resolution immunofluorescence imaging combined with a 3D segmentation method. Immunostaining for phosphorylated Smad1/5/8 shows that BMP signaling is activated in mouse embryos as early as the 4-cell stage, and becomes spatially restricted by late blastocyst stage. Perturbation of BMP signaling in preimplantation mouse embryos, whether by treatment with a small molecule inhibitor, with Noggin protein, or by overexpression of a dominant-negative BMP receptor, indicates that BMPs regulate cell cleavage up to the morula stage. These results indicate that BMP signaling is active during mouse pre-implantation development and is required for cell cleavage in preimplantation mouse embryos.

Dual roles for Id4 in the regulation of estrogen signaling in the mammary gland and ovary

The HLH transcriptional regulator Id4 exerts important roles in different organs, including the neural compartment, where Id4 loss usually results in early lethality. To explore the role of this basally restricted transcription factor in the mammary gland, we generated a cre-inducible mouse model. MMTV- or K14-cre-mediated deletion of Id4 led to a delay in ductal morphogenesis, consistent with previous findings using a germ-line knockout mouse model. A striking increase in the expression of ERα (Esr1), PR and FoxA1 was observed in both the basal and luminal cellular subsets of Id4-deficient mammary glands. Together with chromatin immunoprecipitation of Id4 on the Esr1 and Foxa1 promoter regions, these data imply that Id4 is a negative regulator of the ERα signaling axis. Unexpectedly, examination of the ovaries of targeted mice revealed significantly increased numbers of secondary and antral follicles, and reduced Id4 expression in the granulosa cells. Moreover, expression of the cascade of enzymes that are crucial for estrogen biosynthesis in the ovary was decreased in Id4-deficient females and uterine weights were considerably lower, indicating impaired estrogen production. Thus, compromised ovarian function and decreased circulating estrogen likely contribute to the mammary ductal defects evident in Id4-deficient mice. Collectively, these data identify Id4 as a novel regulator of estrogen signaling, where Id4 restrains ERα expression in the basal and luminal cellular compartments of the mammary gland and regulates estrogen biosynthesis in the ovary.

Anti-Müllerian hormone recruits BMPR-IA in immature granulosa cells

Anti-Müllerian hormone (AMH) is a member of the TGF-β superfamily secreted by the gonads of both sexes. This hormone is primarily known for its role in the regression of the Müllerian ducts in male fetuses. In females, AMH is expressed in granulosa cells of developing follicles. Like other members of the TGF-β superfamily, AMH transduces its signal through two transmembrane serine/threonine kinase receptors including a well characterized type II receptor, AMHR-II. The complete signalling pathway of AMH involving Smads proteins and the type I receptor is well known in the Müllerian duct and in Sertoli and Leydig cells but not in granulosa cells. In addition, few AMH target genes have been identified in these cells. Finally, while several co-receptors have been reported for members of the TGF-β superfamily, none have been described for AMH. Here, we have shown that none of the Bone Morphogenetic Proteins (BMPs) co-receptors, Repulsive guidance molecules (RGMs), were essential for AMH signalling. We also demonstrated that the main Smad proteins used by AMH in granulosa cells were Smad 1 and Smad 5. Like for the other AMH target cells, the most important type I receptor for AMH in these cells was BMPR-IA. Finally, we have identified a new AMH target gene, Id3, which could be involved in the effects of AMH on the differentiation of granulosa cells and its other target cells.

Functional link between bone morphogenetic proteins and insulin-like peptide 3 signaling in modulating ovarian androgen production

Bone morphogenetic proteins (BMPs) are firmly implicated as intra-ovarian regulators of follicle development and steroidogenesis. Here we report a microarray analysis showing that treatment of cultured bovine theca cells (TC) with BMP6 significantly (>twofold; P < 0.01) up- or down-regulated expression of 445 genes. Insulin-like peptide 3 (INSL3) was the most heavily down-regulated gene (-43-fold) with cytochrome P450, subfamily XVII (CYP17A1) and other key steroidogenic transcripts including steroidogenic acute regulatory protein (STAR), cytochrome P450 family 11, subfamily A1 (CYP11A1) and 3 beta-hydroxysteroid dehydrogenase type 1 (HSD3B1) also down-regulated. BMP6 also reduced expression of nuclear receptor subfamily 5A1 (NR5A1) known to target the promoter regions of the aforementioned genes. Real-time PCR confirmed these findings and also revealed a marked reduction in expression of INSL3 receptor, relaxin/insulin-like family peptide receptor 2 (RXFP2). Secretion of INSL3 protein and androstenedione were also suppressed suggesting a functional link between BMP and INSL3 pathways in controlling androgen synthesis. RNAi-mediated knockdown of INSL3 reduced INSL3 mRNA (75%) and protein (94%) level and elicited a 77% reduction in CYP17A1 mRNA and 83% reduction in androstenedione secretion. Knockdown of RXFP2 also reduced CYP17A1 expression (81%) and androstenedione secretion (88%). Conversely, treatment with exogenous (human) INSL3 increased androstenedione secretion ∼twofold. The CYP17A1 inhibitor abiraterone abolished androgen secretion and reduced expression of both INSL3 and RXFP2. Collectively, these findings indicate a positive autoregulatory role for INSL3 signaling in maintaining thecal androgen production, and visa versa. Moreover, BMP6-induced suppression of thecal androgen synthesis may be mediated, at least in part, by reduced INSL3-RXFP2 signaling.

Decreased Expression of Inhibitor of DNA-binding (Id) Proteins and Vascular Endothelial Growth Factor and Increased Apoptosis in Ovarian Aging

This study examined the expression of inhibitor of DNA-binding (Id) proteins and vascular endothelial growth factor (VEGF) in the ovary according to female age using a mice model as the first step in investigating the potential role of Ids and VEGF in ovarian aging. C57BL inbred female mice of three age groups (6-9, 14-16, and 23-26 weeks) were injected with 5 IU pregnant mare’s serum gonadotropin (PMSG) in order to synchronize the estrus cycle. After 48 h, ovarian expression of Ids and VEGF was analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR), western blot and immunohistochemistry. Ovarian apoptosis was examined by ovarian expression of Bcl-2 and Bcl-xL. Expression of Id-1 and VEGF was decreased with advancing female age, but not Id-2, Id-3, and Id-4. In particular, their expressions were significantly decreased in aged mice of 23-26 weeks compared with the young mice of 6-9 weeks (p < 0.05). In contrast, ovarian apoptosis was greatly increased in the aged mice compared to the young mice. This result suggests that Id-1 may have an implicated role in ovarian aging by associating with VEGF.

Improvement of ovarian response and oocyte quality of aged female by administration of bone morphogenetic protein-6 in a mouse model

BACKGROUND

Advancing female age remains a difficult problem in infertility treatment. Ovarian angiogenesis plays an important role in follicular development and the activation of ovarian angiogenesis has been emerged as a new strategy for the improvement of age-related decline of oocyte quality. BMP-6 affect gonadotropin signals in granulosa cells and it promotes normal fertility by enabling appropriate response to LH and normal oocyte quality. BMP-6 has a potential role in regulation of angiogenesis and regulates the expression of inhibitor of DNA-binding proteins (Ids). Ids involved in the control and timing of follicle selection and granulosa cells differentiation. Especially, Id-1 is well-characterized target of BMP-6 signaling. Therefore, this study investigated whether co-administration of BMP-6 during superovulation process improves ovarian response, oocyte quality and expression of Id-1 and vascular endothelial growth factor (VEGF) in the ovary of aged female using a mouse model.

METHODS

Aged C57BL/6 female mice (26-31 weeks old) were superovulated by injection with 0.1 mL of 5 IU equine chorionic gonadotropin (eCG) containing recombinant mouse BMP-6 at various doses (0, 0.01, 0.1, 1, and 10 ng), followed by injection with 5 IU human chorionic gonadotropin (hCG) 48 h later. Then, the mice were immediately paired with an individual male. The aged control group was superovulated without BMP-6. Young mice of 6-9 weeks old were superovulated without BMP-6 as a positive control for superovulation and in vitro culture of embryos. Eighteen hours after hCG injection, zygotes were retrieved and cultured for 4 days. Both ovaries of each mouse were provided in the examination of ovarian expression of Id-1 and VEGF by reverse transcriptase-polymerase chain reaction, western blot, and immunohistochemistry.

RESULTS

Administration of 0.1 ng BMP-6 significantly increased the number and blastocyst formation rate of oocytes ovulated and ovarian expression of Id-1 and VEGF compared to aged control mice. These increased levels were comparable to those of young control mice.

CONCLUSIONS

This result suggests that BMP-6 during ovulation induction plays an important role in improvement of oocyte quality and ovarian response of aged female, possibly by regulating of ovarian Id-1 and VEGF expression.

Expression and localization of inhibitor of differentiation (ID) proteins during tissue and vascular remodelling in the human corpus luteum

Members of the transforming growth factor-β (TGF-β) superfamily are likely to have major roles in the regulation of tissue and vascular remodelling in the corpus luteum (CL). There are four inhibitor-of-differentiation (ID1-4) genes that are regulated by members of the TGF-β superfamily and are involved in the transcriptional regulation of cell growth and differentiation. We studied their expression, localization and regulation in dated human corpora lutea from across the luteal phase (n = 22) and after human chorionic gonadotrophin (hCG) administration in vivo (n = 5), and in luteinized granulosa cells (LGCs), using immunohistochemistry and quantitative RT-PCR. ID1-4 can be localized to multiple cell types in the CL across the luteal phase. Endothelial cell ID3 (P < 0.05) and ID4 (P < 0.05) immunostaining intensities peak at the time of angiogenesis but overall ID1 (P < 0.05) and ID3 (P < 0.05) expression peaks at the time of luteolysis, and luteal ID3 expression is inhibited by hCG in vivo (P < 0.01). In LGC cultures in vitro, hCG had no effect on ID1, down-regulated ID3 (P < 0.001), and up-regulated ID2 (P < 0.001) and ID4 (P < 0.01). Bone morphogenic proteins (BMPs) had no effect on ID4 expression but up-regulated ID1 (P < 0.01 to P < 0.005). BMP up-regulation of ID2 (P < 0.05) was additive to the hCG up-regulation of ID2 expression (P < 0.001), while BMP cancelled out the down regulative effect of hCG on ID3 regulation. As well as documenting regulation patterns specific for ID1, ID2, ID3 and ID4, we have shown that IDs are located and differentially regulated in the human CL, suggesting a role in the transcriptional regulation of luteal cells during tissue and vascular remodelling.

A high concentration of genistein down-regulates activin A, Smad3 and other TGF-β pathway genes in human uterine leiomyoma cells

Previously, we found that high doses of genistein show an inhibitory effect on uterine leiomyoma (UtLM) cell proliferation. In this study, using microarray analysis and Ingenuity Pathways Analysis™, we identified genes (up- or down-regulated, ≥ 1.5 fold, P ≤ 0.001), functions and signaling pathways that were altered following treatment with an inhibitory concentration of genistein (50 µg/ml) in UtLM cells. Downregulation of TGF-β signaling pathway genes, activin A, activin B, Smad3, TGF-β2 and genes related to cell cycle regulation, with the exception of the upregulation of the CDK inhibitor P15, were identified and validated by real-time RT-PCR studies. Western blot analysis further demonstrated decreased protein expression of activin A and Smad3 in genistein-treated UtLM cells. Moreover, we found that activin A stimulated the growth of UtLM cells, and the inhibitory effect of genistein was partially abrogated in the presence of activin A. Overexpression of activin A and Smad3 were found in tissue samples of leiomyoma compared to matched myometrium, supporting the contribution of activin A and Smad3 in promoting the growth of UtLM cells. Taken together, these results suggest that down-regulation of activin A and Smad3, both members of the TGF-β pathway, may offer a mechanistic explanation for the inhibitory effect of a high-dose of genistein on UtLM cells, and might be potential therapeutic targets for treatment of clinical cases of uterine leiomyomas.

Genes of the transforming growth factor-beta signalling pathway are associated with pre-implantation embryonic development in cattle

One of the main factors affecting cattle fertility is pre-implantation development of the bovine embryo, which is a complex process regulated by various signal-transduction pathways. The transforming growth factor-β (TGF-β) signalling system, which is responsible for many biological processes including cell proliferation, differentiation and apoptosis, also is involved in embryo development. We hypothesized that altered expression of TGF-β genes in pre-implantation bovine embryos is associated with morphological abnormalities of these embryos. To test this hypothesis, we produced embryos in vitro and classified them at the blastocyst stage as either normally developed blastocysts or degenerates (growth-arrested embryos). The expression patterns of 25 genes from the TGF-β pathway were assessed using quantitative real time PCR. Ten genes showed differential expression between the two embryo groups, four genes displayed similar expressional profiles, and 11 genes had no detectable expression. An altered expression profile was statistically significant for 10 of the 14 expressed genes, and all were up-regulated in degenerate embryos vs. blastocysts. Furthermore, genomic association analysis of the cows from which embryos were produced revealed a significant association of ID3 and BMP4 polymorphisms--two of the most significant differentially expressed genes--with fertilization rate and blastocyst rate, respectively. Taken together, we conclude that TGF-β pathway genes, especially BMP4 and ID3 play a vital function in the regulation of pre-implantation embryo development at both embryo and maternal levels. Hence, these genes may be suitable as genetic markers for embryo development and fertility in cattle.

Bone morphogenetic protein signaling transcription factor (SMAD) function in granulosa cells

The transforming growth factor β (TGFβ) family of proteins are key regulators of growth and differentiation. Members of this family, including multiple TGFβs, activins, bone morphogenetic proteins (BMPs), and growth and differentiation factor 9 (GDF9), are expressed from oocytes or their associated follicular somatic cells (granulosa and thecal cells) with cell-type and stage-dependent specificity. Granulosa cells are the target cells for many of these ligands. Granulosa cell-specific knockout mice for all of the receptor-regulated SMADs, as well as the common regulatory SMAD4, have recently been generated and highlight the importance of this family in most stages of folliculogenesis. These models have also uncovered a novel role for the BMPs in suppression of granulosa cell tumor development and metastasis. This review summarizes the phenotypes of these mouse models and their contribution to our understanding of the complexity of BMP function during follicle development.

TGF-β mediated DNA methylation in prostate cancer

Almost all tumors harbor a defective negative feedback loop of signaling by transforming growth factor-β (TGF-β). Epigenetic mechanisms of gene regulation, including DNA methylation, are fundamental to normal cellular function and also play a major role in carcinogenesis. Recent evidence demonstrated that TGF-β signaling mediates cancer development and progression. Many key events in TGF-β signaling in cancer included auto-induction of TGF-β1 and increased expression of DNA methyltransferases (DNMTs), suggesting that DNA methylation plays a significant role in cancer development and progression. In this review, we performed an extensive survey of the literature linking TGF-β signaling to DNA methylation in prostate cancer. It appeared that almost all DNA methylated genes detected in prostate cancer are directly or indirectly related to TGF-β signaling. This knowledge has provided a basis for our future directions of prostate cancer research and strategies for prevention and therapy for prostate cancer.

Bone morphogenetic protein 6 promotes FSH receptor and anti-Müllerian hormone mRNA expression in granulosa cells from hen prehierarchal follicles

A growing body of literature provides evidence of a prominent role for bone morphogenetic proteins (BMPs) in regulating various stages of ovarian follicle development. Several actions for BMP6 have been previously reported in the hen ovary, yet only within postselection (preovulatory) follicles. The initial hypothesis tested herein is that BMP6 increases FSH receptor (FSHR) mRNA expression within the granulosa layer of prehierarchal (6-8 mm) follicles (6-8 GC). BMP6 mRNA is expressed at higher levels within undifferentiated (1-8 mm) follicles compared with selected (≥9 mm) follicles. Recombinant human (rh) BMP6 initiates SMAD1, 5, 8 signaling in cultured 6-8 GC and promotes FSHR mRNA expression in a dose-related fashion. In addition, a 21 h preculture with rhBMP6 followed by a 3 h challenge with FSH increases cAMP accumulation, STAR (StAR) expression, and progesterone production. Interestingly, rhBMP6 also increases expression of anti-Müllerian hormone (AMH) mRNA in cultured 6-8 GC. This related BMP family member has previously been implicated in negatively regulating FSH responsiveness during follicle development. Considering these data, we propose that among the paracrine and/or autocrine actions of BMP6 within prehierarchal follicles is the maintenance of both FSHR and AMH mRNA expression. We predict that before follicle selection, one action of AMH within granulosa cells from 6 to 8 mm follicles is to help suppress FSHR signaling and prevent premature granulosa cell differentiation. At the time of selection, we speculate that the yet undefined signal directly responsible for selection initiates FSH responsiveness. As a result, FSH signaling suppresses AMH expression and initiates the differentiation of granulosa within the selected follicle.

Inhibin removes the inhibitory effects of activin on steroid enzyme expression and androgen production by normal ovarian thecal cells

Activin and inhibin are important local modulators of theca cell steroidogenesis in the ovary. Using a serum-free primary theca cell culture system, this study investigated the effects of inhibin on theca cell androgen production and expression of steroidogenic enzymes. Androstenedione secretion from theca cells cultured in media containing activin, inhibin and follistatin was assessed by RIA over 144 h. Activin (1-100 ng/ml) suppressed androstenedione production. Inhibin (1-100 ng/ml) blocked the suppressive effects of added activin, but increased androstenedione production when added alone, suggesting it was blocking endogenous activin produced by theca cells. Addition of SB-431542 (activin receptor inhibitor) and follistatin (500 ng/ml) increased androstenedione production, supporting this concept. Infection of theca cells with adenoviruses expressing inhibitory Smad6 or 7 increased androstenedione secretion, confirming that the suppressive effects of activin required activation of the Smad2/3 pathway. Activin decreased the expression levels of steroidogenic acute regulatory protein (STAR), whereas STAR expression was increased by inhibin and SB-431542, alone and in combination. CYP11A was unaffected. The expression of CYP17 encoding 17α-hydroxylase was unaffected by activin but increased by inhibin and SB-431542, and when added in combination the effect was further enhanced. The expression of 3β-hydroxysteroid dehydrogenase (3β-HSD) was significantly decreased by activin, while inhibin alone and in combination with SB-431542 both potently increased the expression of 3β-HSD. In conclusion, activin suppressed theca cell androstenedione production by decreasing the expression of STAR and 3β-HSD. Inhibin and other blockers of activin action reversed this effect, supporting the concept that endogenous thecal activin modulates androgen production in theca cells.

Human cumulus cells molecular signature in relation to oocyte nuclear maturity stage

The bi-directional communication between the oocyte and the surrounding cumulus cells (CCs) is crucial for the acquisition of oocyte competence. We investigated the transcriptomic profile of human CCs isolated from mature and immature oocytes under stimulated cycle. We used human Genome U133 Plus 2.0 microarrays to perform an extensive analysis of the genes expressed in human CCs obtained from patients undergoing intra-cytoplasmic sperm injection. CC samples were isolated from oocyte at germinal vesicle, stage metaphase I and stage metaphase II. For microarray analysis, we used eight chips for each CC category. Significance analysis of microarray multiclass was used to analyze the microarray data. Validation was performed by RT-qPCR using an independent cohort of CC samples. We identified differentially over-expressed genes between the three CC categories. This study revealed a specific signature of gene expression in CCs issued from MII oocyte compared with germinal vesicle and metaphase I. The CC gene expression profile, which is specific of MII mature oocyte, can be useful as predictors of oocyte quality.

Prenatal androgen exposure leads to alterations in gene and protein expression in the ovine fetal ovary

Exposure of a female fetus to increased androgens in utero results in an adult phenotype reminiscent of polycystic ovary syndrome. We investigated whether prenatal androgens could directly alter the structure and function of the fetal ovary. We examined fetal ovarian cell proliferation, germ cell volume, and the expression of steroid receptors and steroidogenic enzymes. In addition, we studied the inhibitors of differentiation (Ids) and the SLIT/Roundabout developmental pathways. Female fetuses were collected from ewes treated with 100 mg testosterone propionate (TP) or vehicle control (C), twice weekly from d 60 to 70 (C = 3, TP = 6) or d 90 (C = 6, TP = 8). Female fetuses were also collected at d 70 after a single injection of TP (20 mg) or vehicle C into the fetal flank at d 60 (C = 4, TP = 8). Prenatal androgenization had no effect on fetal ovarian morphology, cell proliferation, or germ cell volume. However, there was a reduction in the expression of StAR, CYP11A, CYP17, and LHR at d 90 of gestation. There was also an increase in Id1 immunostaining at d 90 and an increase in Id3 immunostaining at d 70. Direct injection of TP into the fetus down-regulated ovarian CYP11A, estrogen receptor α and β mRNA, and ROBO1 and up-regulated CYP19, androgen receptor immunostaining, and Id3 mRNA and protein. Although at d 90 prenatal androgenization does not result in structural changes of the fetal ovary, there are functional changes that may impact on ovarian development. TP has direct actions on the fetal ovary, and these may contribute to the adult ovarian phenotype in the ovine model of polycystic ovary syndrome.

Does bone morphogenetic protein 6 (BMP6) affect female fertility in the mouse?

Bone morphogenetic protein 6 (BMP6) is a transforming growth factor beta superfamily member produced by mammalian oocytes as well as other cell types. Despite well-characterized effects of recombinant BMP6 on granulosa cells in vitro, the function of BMP6 in vivo has been ill-defined. Therefore, the effects of genetic deletion of the Bmp6 gene on female mouse fertility were assessed. The mean litter size of Bmp6(-/-) females was reduced by 22% (P < 0.05) compared to Bmp6(+/+) controls. Not only did Bmp6(-/-) females naturally ovulate 24% fewer eggs, but competence of in vitro-matured oocytes to complete preimplantation development after fertilization in vitro was decreased by 50%. No apparent effect of Bmp6 deletion on either the morphology or the dynamics of follicular development was apparent. Nevertheless, levels of luteinizing hormone (LH)/human chorionic gonadotropin (hCG)-induced transcripts, which encode proteins required for cumulus expansion (HAS2, PTGS2, PTX3, and TNFAIP6), and of epidermal growth factor-like peptides (AREG, BTC, and EREG) were lower in Bmp6(-/-) mice than in controls after administration of a reduced dose of hCG (1 IU) in vivo. LH receptor (Lhcgr) transcript levels were not significantly lower in Bmp6(-/-) granulosa cells, suggesting that BMP6 is required for processes downstream of LH receptors. To assess whether another oocyte-derived BMP, BMP15, could have BMP6-redundant functions in vivo, the fertility of Bmp15/Bmp6 double mutants was assessed. Fertility was not significantly reduced in double-homozygous mutants compared with that in double-heterozygous controls. Therefore, BMP6 promotes normal fertility in female mice, at least in part, by enabling appropriate responses to LH and normal oocyte quality. Thus, Bmp6 probably is part of the complex genetic network that determines female fertility.

Steroidal and gonadal effects on neural cell proliferation in vitro in an adult songbird

Neurogenesis in the adult songbird brain occurs along the ventricular zone (VZ), a specialized cell layer surrounding the lateral ventricles. To examine the acute effects of sex steroids on VZ cell proliferation, male and female adult zebra finch brain slices containing the VZ were exposed to 5-bromo-2'-deoxyuridine-5'-monophosphate (BrdU) in vitro. Slices from one hemisphere served as the control, while contralateral slices were treated with steroids, steroidogenic enzyme inhibitors or gonadal tissue itself. There were no significant effects on VZ cell proliferation in either sexes by acute exposure to 17beta-estradiol (E2), dihydrotestosterone (DHT), a cocktail of four sex steroids, and inhibitors of sex steroid synthesis (aminoglutethimide, ketoconazole, and fadrozole), or by activation of a mitochondrial cholesterol transporter. By contrast, dehydroepiandrosterone (DHEA) suppressed VZ cell proliferation in males, but not females, replicating previous observations involving treatments with corticosterone and RU-486. This suggests that DHEA suppresses proliferation in males via a glucocorticoid receptor-related mechanism. These results suggest that neurosteroidogenesis per se has little effect on acute VZ cell proliferation. Co-incubation with an ovary of female, but not male, slices significantly increased VZ cell proliferation; testicular tissue had no impact on proliferation in males or females. This suggests a role for a non-steroidal ovarian factor on adult female VZ cell proliferation. We also have evidence that previously reported sex-differences in BrdU-labeling along the adult VZ (males>females) result from a more rapid loss of cells in females. Sex differences in steroid action and cell death along the VZ may contribute to the maintenance of the sexually dimorphic song system.