Loss of vascular endothelial growth factor A (VEGFA) isoforms in granulosa cells using pDmrt-1-Cre or Amhr2-Cre reduces fertility by arresting follicular development and by reducing litter size in female mice

Comparison of chromatin accessibility remodeling of granulosa cells in patients with endometrioma or pelvic/tubal infertility

PURPOSE

To elucidatethe epigenetic alteration associated with impaired oogenesis in endometrioma using multi-omic approaches.

METHODS

ATAC-seq was performed on the granulosa cells (GCs) of 6 patients (3 with endometrioma and 3 without). Follicular samples from another 20 patients (10 with endometrioma and 10 without) were collected for mRNA-seq analysis of GCs and extracellular vesicles (EVs) of follicular fluid. qRT-PCR validated candidate genes in GCs from 44 newly enrolled patients (19 with endometrioma and 25 without). mRNA abundance was compared with the Mann-Whitney test. Pearson's correlation analyzed relationships between candidate genes and oocyte parameters.

RESULTS

Chromatin accessibility and gene expression profiles of GCs from endometrioma patients differed significantly from the pelvic/tubal infertility group. RNA-seq revealed most differentially expressed genes were downregulated (6216/7325) and enriched in the cellular localization pathway. Multi-omics analyses identified 22 significantly downregulated genes in the GCs of endometrioma patients, including PPIF (P < 0.0001) and VEGFA (P = 0.0148). Both genes were further confirmed by qRT-PCR. PPIF (r = 0.46, p = 0.043) and VEGFA (r = 0.45, p = 0.048) correlated with the total number of retrieved oocytes.

CONCLUSIONS

GC chromatin remodeling may disrupt GC and EV transcriptomes, interfering with somatic cell-oocyte communication and leading to compromised oogenesis in endometrioma patients.

Unlocking Genetic Mysteries during the Epic Sperm Journey toward Fertilization: Further Expanding Cre Mouse Lines

The spatiotemporal expression patterns of genes are crucial for maintaining normal physiological functions in animals. Conditional gene knockout using the cyclization recombination enzyme (Cre)/locus of crossover of P1 (Cre/LoxP) strategy has been extensively employed for functional assays at specific tissue or developmental stages. This approach aids in uncovering the associations between phenotypes and gene regulation while minimizing interference among distinct tissues. Various Cre-engineered mouse models have been utilized in the male reproductive system, including Dppa3-MERCre for primordial germ cells, Ddx4-Cre and Stra8-Cre for spermatogonia, Prm1-Cre and Acrv1-iCre for haploid spermatids, Cyp17a1-iCre for the Leydig cell, Sox9-Cre for the Sertoli cell, and Lcn5/8/9-Cre for differentiated segments of the epididymis. Notably, the specificity and functioning stage of Cre recombinases vary, and the efficiency of recombination driven by Cre depends on endogenous promoters with different sequences as well as the constructed Cre vectors, even when controlled by an identical promoter. Cre mouse models generated via traditional recombination or CRISPR/Cas9 also exhibit distinct knockout properties. This review focuses on Cre-engineered mouse models applied to the male reproductive system, including Cre-targeting strategies, mouse model screening, and practical challenges encountered, particularly with novel mouse strains over the past decade. It aims to provide valuable references for studies conducted on the male reproductive system.

Special Staining and Protein Expression of VEGF/EGFR and P53/NF-κB in Cryptorchid Tissue of Erhualian Pigs

Erhualian pigs exhibit one of the highest reproductive rates globally, and cryptorchidism is a crucial factor affecting reproductive abilities of boars. This investigation focused on cryptorchid tissues from Erhualian pigs, where the histological structure of cryptorchidism was observed using specialized staining. In addition, protein expression of P53/NF-κB in cryptorchid tissues was assessed using Western blot and immunohistochemistry. In comparison to normal Erhualian testes, Masson's trichrome staining indicated a reduction in collagen fibers in the connective tissue and around the basal membrane of the seminiferous tubules in cryptorchid testes. Moreover, collagen fiber distribution was observed to be disordered. Verhoeff Van Gieson (EVG) and argyrophilic staining demonstrated brownish-black granular nucleoli organized regions in mesenchymal cells and germ cells. When compared to normal testicles, the convoluted seminiferous tubules of cryptorchids exhibited a significantly reduced number and diameter (p < 0.01). Notably, VEGF/EGFR and P53/NF-κB expression in cryptorchidism significantly differed from that in normal testes. In particular, the expression of VEGF and P53 in cryptorchid tissues was significantly higher than that in normal testes tissues, whereas the expression of EGFR in cryptorchid tissues was significantly lower than that in normal testes tissues (all p < 0.01). NF-κB expressed no difference in both conditions. The expressions of VEGF and NF-κB were observed in the cytoplasm of testicular Leydig cells and spermatogenic cells, but they were weak in the nucleus. EGFR and P53 were more positively expressed in the cytoplasm of these cells, with no positive expression in the nucleus. Conclusion: There were changes in the tissue morphology and structure of the cryptorchid testis, coupled with abnormally high expression of VEGF and P53 proteins in Erhualian pigs. We speculate that this may be an important limiting factor to fecundity during cryptorchidism.

Effects of follicle-stimulating hormone, insulin-like growth factor 1, fibroblast growth factor 2, and fibroblast growth factor 9 on sirtuins expression and histone deacetylase activity in bovine granulosa cells

Granulosa cells (GC) are critical regulators of fertility. During the process of ovarian folliculogenesis, these cells undergo profound changes while producing steroid hormones that are important to control follicular growth, oocyte maturation, and ovulation. Sirtuins are enzymes that regulate several biological processes and have been associated with control of GC function. However, how sirtuins are regulated in GC during ovarian folliculogenesis remains to be unveiled. The present study was designed to investigate effects of hormones that control GC proliferation, differentiation, and steroidogenesis on expression of the seven members of the mammalian sirtuins family (SIRT1-7) and on histone deacetylase activity of nuclear sirtuins (SIRT1, 6, and 7) in GC. Bovine granulosa cells were isolated from small antral follicles (1-5 mm) and were treated with or without follicle-stimulating hormone (FSH), insulin-like growth factor 1 (IGF-1), and fibroblast growth factors 2 (FGF2) and 9 (FGF9). Following treatments, cell proliferation was determined via a cell analyzer, estradiol synthesis and histone deacetylase activity were determined via ELISA, and sirtuins mRNA expression was determined via qPCR. Treatments with FSH and IGF-1 stimulated cell proliferation while addition of FGF2 or FGF9 suppressed estradiol production stimulated by FSH plus IGF-1. In terms of treatments that regulated sirtuins expression in GC, fibroblast growth factors were the most impactful: FGF2 alone increased SIRT1 mRNA expression in comparison to several treatments and increased mRNA abundance of SIRT2 and SIRT7 when added to the combination of FSH and IGF-1; the addition of FGF9 to the combination of FSH and IGF-1 increased mRNA expression of SIRT2, SIRT3, SIRT4, SIRT6, and SIRT7 and increased mRNA expression of SIRT5 in comparison to the negative control group that received no treatment. Also, FGF2 alone increased histone deacetylase activity of sirtuins in comparison to all treatments that contained FSH and/or IGF-1. Furthermore, several correlations were observed between treatments and sirtuins expression and activity, between estradiol or GC numbers and sirtuins expression, and between expression of sirtuins. As FGF2 and FGF9 are considered anti-differentiation factors of GC that stimulate GC proliferation while suppressing estradiol production in combination with FSH and IGF-1, data of this study suggest that sirtuins are associated with control of differentiation of bovine GC.

Potential biomarkers to predict return to fertility after discontinuation of female contraceptives-looking to the future

Nowadays there are multiple types of contraceptive methods, from reversible to permanent, for those choosing to delay pregnancy. Misconceptions about contraception and infertility are a key factor for discontinuation or the uptake of family planning methods. Regaining fertility (the ability to conceive) after contraceptive discontinuation is therefore pivotal. Technical studies to date have evaluated return to fertility by assessing pregnancy as an outcome, with variable results, or return to ovulation as a surrogate measure by assessing hormone levels (such as progesterone, LH, FSH) with or without transvaginal ultrasound. In general, relying on time to pregnancy as an indicator of return to fertility following contraceptive method discontinuation can be problematic due to variable factors independent of contraceptive effects on fertility, hormone clearance, and fertility recovery. Since the ability to conceive after contraceptive method discontinuation is a critical factor influencing product uptake, it is important to have robust biomarkers that easily and accurately predict the timing of fertility return following contraception and isolate that recovery from extrinsic and circumstantial factors. The main aim of this review is to summarize the current approaches, existing knowledge, and gaps in methods of evaluating return-to-fertility as well as to provide insights into the potential of new biomarkers to more accurately predict fertility restoration after contraceptive discontinuation. Biomarker candidates proposed in this document include those associated with folliculogenesis, cumulus cell expansion, follicular rupture and ovulation, and endometrial transport and receptivity which have been selected and scored on predefined criteria meant to evaluate their probable viability for advancement. The review also describes limitations, regulatory requirements, and a potential path to clinically testing these selected biomarkers. It is important to understand fertility restoration after contraceptive method discontinuation to provide users and health providers with accurate evidence-based information. Predictive biomarkers, if easy and low-cost, have the potential to enable robust evaluation of RTF, and provide potential users the information they desire when selecting a contraceptive method. This could lead to expanded uptake and continuation of modern contraception and inform the development of new contraceptive methods to widen user's family planning choices.

Effects of vascular endothelial growth factor (VEGF) on the viability, apoptosis and steroidogenesis of yak (Bos grunniens) granulosa cells

Vascular endothelial growth factor (VEGF) is crucial for follicle development through the regulation of granulosa cell (GC) function in some mammals, but its mechanism is unclear in yak (Bos grunniens). Therefore, the objectives of this study were to investigate the effects of VEGF on the viability, apoptosis and steroidogenesis of yak GCs. First, we investigated the localization of VEGF and its receptor (VEGFR2) in yak ovaries by immunohistochemistry analysis and evaluated the effect of culture medium containing different VEGF concentrations and culture times on the viability of yak GCs by Cell Counting Kit-8. Then, optimal treatment with 20 ng/mL VEGF for 24 h was selected to analyze the effects of this compound on intracellular reactive oxygen species levels by DCFH-DA kit, cell cycle and apoptosis by flow cytometry, steroidogenesis by ELISA kit and the expression of the related genes by RT‒qPCR. The results showed that VEGF and VEGFR2 were highly coexpressed in GCs and theca cells. GCs cultured in medium containing 20 ng/mL VEGF for 24 h significantly improved cell viability, decreased ROS production, promoted the transition from G1 phase to S phase (P < 0.05), increased the expression of the CCND1 (P < 0.05), CCNE1, CDK2, CDK4, and PCNA genes (P < 0.01) and decreased the expression of the P53 gene (P < 0.05). This treatment significantly reduced GC apoptosis (P < 0.05) by promoting the expression of BCL2 and GDF9 (P < 0.01) and inhibiting the expression of BAX and CASPASE3 (P < 0.05). VEGF promoted progesterone secretion (P < 0.05) accompanied by increased expression of HSD3B, StAR and CYP11A1 (P < 0.05). Taken together, our findings highlight the beneficial influence exerted by VEGF in improving GC viability and reducing ROS production and the apoptosis rate through the modulation of related gene expression.

Identifying selection signatures for litter size in Guangxi Bama Xiang pigs

Litter size is an important economic trait in pig production. However, the genetic mechanisms underlying varying litter size in Guangxi Bama Xiang pigs remain unknown. To identify selection signatures for litter size in Guangxi Bama Xiang pigs, we obtained 297 Illumina PorcineSNP50 BeadChip array data and the average born number (ABN) from parity one to nine in Guangxi Bama Xiang pigs. Fixation index (Fst) methods were used to identify the selection signature of the litter size, and three phenotypic gradient differential population pairs (according to the ABN) in individuals were used to reduce the false positives of signature selections. Single nucleotide polymorphisms (SNPs) were identified in the VEGFA promoter and exons. The general linear model was used to analyse the differences in distinct genotypes after they were typed using three-round multiplex PCR technology. Finally, the transcriptome factor and CpG island in the VEGFA promoter were predicted. A total of 328, 328 and 317 significant loci were identified in the 1st, 2nd and 3rd population pairs, respectively. After removing the false positives, 25 SNPs were defined as the selection signatures in relation to litter size. Ten (VEGFA, USP49, USP25, SRPK1, SLC26A8, RPL10A, PPARD, MAPK14, HMGA1 and CHRDL2) out of 52 genes in the selection regions were annotated as the candidate genes of litter size, respectively, VEGFA. There were no SNPs in the VEGFA exon region, but we obtained three SNPs (rs786889605, rs343769603 and rs323942424) in the VEGFA promoter regions. The ABN in CC was significantly higher than that in TT in rs786889605, and the ABN in TT was significantly lower than that in GG in rs323942424. Meanwhile, the mutation of the VEGFA promoter result in the loss of Sp1 and NF-1 and the formation of Oct-1. In summary, we obtained ten candidate genes, and two mutations in the VEGFA promoter that could be important potential molecular biomarkers for litter size in Bama Xiang pigs.

Short variation of the sheep PDGFD gene is correlated with litter size

Platelet-derived growth factor (PDGF) family, exert plays a key role in embryonic development, cell proliferation, cell migration, angiogenesis and reproduction. Related studies about GWAS analyses have found that PDGFD significantly affected deposition of tail fat in sheep, but there are no studies on reproduction in animals. In this study, three breed of sheep were used to find insertion/deletion (indel) fragment polymorphism of PDGFD which including Australian white (AUW) sheep (Meat type, n = 932), Guiqian semi-fine wool (GSFW) sheep (wool type, n = 60) and East Friensian milk (EFM) sheep (dairy type, n = 60). Only a 18-bp variation was polymorphic in the study AUW sheep population and the genotypes of different sheep breed are also specific. Moreover, the association analysis indicated that this variant was associated with litter size of AUW sheep in the first parity (p < 0.05). The litter size of II genotype was significantly lower than other genotypes in the first parity (p < 0.05). We also revealed that the PDGFD gene was relatively conservative in eight species, PDGFD mRNA expression in 832 sheep samples implying this gene was related to reproduction traits. Hence, these finding demonstrated the one-cause multipotency of PDGFD gene. Collectively, these results suggest that this indel can be used as an effective marker for sheep breeding.

Prenatal Exposure to Delta-9-tetrahydrocannabinol (THC) Alters the Expression of miR-122-5p and Its Target Igf1r in the Adult Rat Ovary

As cannabis use during pregnancy increases, it is important to understand its effects on the developing fetus. Particularly, the long-term effects of its psychoactive component, delta-9-tetrahydrocannabinol (THC), on the offspring’s reproductive health are not fully understood. This study examined the impact of gestational THC exposure on the miRNA profile in adult rat ovaries and the possible consequences on ovarian health. Prenatal THC exposure resulted in the differential expression of 12 out of 420 evaluated miRNAs. From the differentially expressed miRNAs, miR-122-5p, which is highly conserved among species, was the only upregulated target and had the greatest fold change. The upregulation of miR-122-5p and the downregulation of its target insulin-like growth factor 1 receptor (Igf1r) were confirmed by RT-qPCR. Prenatally THC-exposed ovaries had decreased IGF-1R-positive follicular cells and increased follicular apoptosis. Furthermore, THC decreased Igf1r expression in ovarian explants and granulosa cells after 48 h. As decreased IGF-1R has been associated with diminished ovarian health and fertility, we propose that these THC-induced changes may partially explain the altered ovarian follicle dynamics observed in THC-exposed offspring. Taken together, our data suggests that prenatal THC exposure may impact key pathways in the developing ovary, which could lead to subfertility or premature reproductive senescence.

In Silico Identification of lncRNAs Regulating Sperm Motility in the Turkey (Meleagris gallopavo L.)

Long non-coding RNAs (lncRNAs) are transcripts not translated into proteins with a length of more than 200 bp. LncRNAs are considered an important factor in the regulation of countless biological processes, mainly through the regulation of gene expression and interactions with proteins. However, the detailed mechanism of interaction as well as functions of lncRNAs are still unclear and therefore constitute a serious research challenge. In this study, for the first time, potential mechanisms of lncRNA regulation of processes related to sperm motility in turkey were investigated and described. Customized bioinformatics analysis was used to detect and identify lncRNAs, and their correlations with differentially expressed genes and proteins were also investigated. Results revealed the expression of 863 new/unknown lncRNAs in ductus deferens, testes and epididymis of turkeys. Moreover, potential relationships of the lncRNAs with the coding mRNAs and their products were identified in turkey reproductive tissues. The results obtained from the OMICS study may be useful in describing and characterizing the way that lncRNAs regulate genes and proteins as well as signaling pathways related to sperm motility.

Cathepsin B Regulates Mice Granulosa Cells' Apoptosis and Proliferation In Vitro

Cathepsin B (CTSB), a lysosomal cysteine protease’s high expression and activity, has been reported to cause poor-quality embryos in porcine and bovine. Nevertheless, CTSB functions in mice granulosa cells remain to explore. To discuss the CTSB functional role in follicular dynamics, we studied apoptosis, proliferation, cell cycle progression, and related signaling pathways in primary mouse granulosa cells transfected with small interference RNA specific to CTSB (siCTSB) for 48 h. Further, mRNA and protein expression of cell proliferation regulators (Myc and cyclin D2), apoptosis regulators (caspase 3, caspase 8, TNF-α, and Bcl2), steroidogenesis-related genes (FSHR and CYP11A1), and autophagy markers (LC3-I and ATG5) were investigated. In addition, the effect of CTSB on steroidogenesis and autophagy was also examined. Flow cytometry analysis assay displayed that silencing of CTSB decreased the early and total apoptosis rate by downregulating TNF-α, caspase 8, and caspase 3, and upregulating Bcl2. By regulating Myc and cyclin D2 expression and activating the p-Akt and p-ERK pathways, CTSB knockdown increased GC proliferation and number. A significant decline in estradiol and progesterone concentrations was observed parallel to a significant decrease in autophagy-related markers LC3-I and ATG5 compared to the control group. Herein, we demonstrated that CTSB serves as a proapoptotic agent and plays a critical role in folliculogenesis in female mice by mediating apoptosis, autophagy, proliferation, and steroidogenesis. Hence, CTSB could be a potential prognostic agent for female infertility.

Orexin-A Regulates Follicular Growth, Proliferation, Cell Cycle and Apoptosis in Mouse Primary Granulosa Cells via the AKT/ERK Signaling Pathway

Granulosa cells (GCs) are essential for follicular growth, development, and atresia. The orexin-A (OXA) neuropeptide is widely involved in the regulation of various biological functions. OXA selectively binds to orexin receptor type 1 (OX1R) and mediates all its biological actions via OX1R. This study aimed to explore the expression of OXA and OX1R and their regulatory role in GCs proliferation, cell cycle progression, apoptosis, oocyte maturation, and underlying molecular mechanisms of these processes and elucidate its novel signaling pathway. Western blotting and RT-qPCR showed that OXA and OX1R were expressed during different developmental stages of GCs, and siRNA transfection successfully inhibited the expression of OX1R at the translational and transcriptional levels. Flow cytometry revealed that OX1R knockdown upregulated GCs apoptosis and triggered S-phase arrest in cell cycle progression. RT-qPCR and Western blotting showed significantly reduced expression of Bcl-2 and elevated expression of Bax, caspase-3, TNF-α, and P21 in OX1R-silenced GCs. Furthermore, the CCK-8 assay showed that knockdown of OX1R suppressed GCs proliferation by downregulating the expression of PCNA, a proliferation marker gene, at the translational and transcriptional levels. Western blotting revealed that knockdown of OX1R resulted in a considerable decrease of the phosphorylation level of the AKT and ERK1/2 proteins, indicating that the AKT/ERK1/2 pathway is involved in regulating GCs proliferation and apoptosis. In addition, OX1R silencing enhanced the mRNA expression of GDF9 and suppressed the mRNA expression of BMP15 in mouse GCs. Collectively, these results reveal a novel regulatory role of OXA in the development of GCs and folliculogenesis by regulating proliferation, apoptosis, and cell cycle progression. Therefore, OXA can be a promising therapeutic agent for female infertility.

Bisphenol analogs AF and S: Effects on cell status and production of angiogenesis-related factors by COV434 human granulosa cell line

While Bisphenol A (BPA) has been a requisite plastic additive, as an endocrine disruptor it has been associated with adverse health effects including ovarian disorders. Following implemented restrictions on BPA usage, it is replaced by alternative bisphenols, biological effects of which have not been adequately investigated. Our study examined effects of bisphenols AF (BPAF) and S (BPS), on the human ovarian granulosa cell line COV434, and compared them with BPA, with the focus on cell viability (10^-9-10^-4 M) and angiogenesis-related factors (10^-9-10^-5 M), relevant for both the follicle development and ovarian pathologies: vascular endothelial growth factor A (VEGF-A), platelet-derived growth factor AA (PDGF-AA), and matrix metalloproteinase 9 (MMP-9). Each bisphenol impaired cell viability and increased generation of intracellular reactive oxygen species at the highest concentration (10^-4 M). While VEGF-A production in BPAF-treated groups did not differ from the control, all doses of BPS and BPA caused a marked reduction in VEGF-A output. Nevertheless, the alterations in VEGF-A production were not caused by the impact on VEGFA gene expression since there were no indications of VEGFA downregulation in the presence of either BPS or BPA. Interestingly, we observed a similar pattern of PDGF-AA output reduction in BPS- and BPA-treated groups to that of VEGF-A production. BPAF and BPS (10^-5 M) increased MMP9 expression, however, this effect was not reflected by the increase in MMP-9 production. The results obtained demonstrate that the novel bisphenol analogs are not inert with respect to the ovarian cells, and their effects might contribute to dysregulation of granulosa cells functions.

Comparison of Human Antral Follicles of Xenograft versus Ovarian Origin Reveals Disparate Molecular Signatures

The activation, growth, and maturation of oocytes to an ovulatory phase, termed folliculogenesis, is governed by the orchestrated activity of multiple specialized cell types within the ovary; yet, the mechanisms governing diversification and behavior of discrete cellular sub-populations within follicles are poorly understood. We use bulk and single-cell RNA sequencing to distinguish the transcriptional signature of prospectively isolated granulosa and theca/stroma cell subsets within human antral follicles derived from xenografts or ovaries. The analysis deconstructs phenotypic diversification within small (<4 mm) antral follicles, identifying secreted factors that are differentially enriched between mural and oophorus granulosa cells, and segregating stromal/support and steroidal activity between theca externa and interna, respectively. Multiple factors are differentially expressed in follicles of xenograft versus ovarian origin. These data capture a high-resolution transcriptional signature of granulosa and theca subpopulations and provide a systems-level portrait of cellular diversification in early antral human follicles.

Differential molecular and hormonal changes in oocytes, granulosa cells and follicular fluid of pregnant and non-pregnant camels

This study aimed to compare the expression of genes regulating follicles development, survival and steroid hormones secretion in oocytes and granulosa cells (GCs) and study the correlation between their expression and follicular fluid (FF) levels of progesterone (P4) in pregnant and non-pregnant camels. In total, 138 ovarian pairs from slaughtered camels were used. Gene expression and hormonal assay were determined using real-time polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA), respectively. The obtained results revealed that the number of follicles (3-8 mm) was significantly (P < 0.05) lower in pregnant, compared with non-pregnant, camels. P4 level in the FF was significantly (P < 0.05) higher in pregnant, compared with non-pregnant, camels. However, no significant (P > 0.05) difference was noticed in the oestradiol (E2) level. STAR, PTEN, IGF1 and BCL2 mRNA levels were significantly higher in GCs and significantly lower in oocytes of pregnant, compared with non-pregnant, camels. However, follicle-stimulating hormone receptor (FSHR) mRNA level was significantly lower in GCs and oocytes, and the BMP15 mRNA level was significantly lower in oocytes of pregnant, compared with non-pregnant, camels. P4 level in FF was positively correlated with STAR, PTEN, IGF1 and BCL2 mRNA levels in GCs and negatively correlated with BMP15 mRNA levels in oocytes and FSHR mRNA levels in GCs and oocytes of pregnant camels. It could be concluded that pregnancy-induced variations in oocytes and GC expression of BMP15, IGF1, FSHR, STAR, BCL2, and PTEN genes might be associated with a decrease in the number of follicles and an increase in the FF level of P4.

Regulation of the transcription factor E2F8 gene expression in bovine ovarian cells

Overexpression of the transcription factor, E2F8, has been associated with ovarian cancer. Objectives of this study were to determine: 1) if E2F8 gene expression in granulosa cells (GC) and theca cells (TC) change with follicular development, and 2) if E2F8 mRNA abundance in TC and GC is hormonally regulated. Using real-time PCR, E2F8 mRNA abundance in GC and TC was greater (P < 0.05) in small than large follicles. FGF9 induced an increase (P < 0.05) in E2F8 mRNA abundance by 1.6- to 7-fold in large-follicle (8-20 mm) TC and GC as well as in small-follicle (1-5 mm) GC. Abundance of E2F8 mRNA in TC was increased (P < 0.05) with FGF2, FGF9 or VEGFA treatments alone in vitro, and concomitant treatment of VEGFA with FGF9 increased (P < 0.05) abundance of E2F8 mRNA above any of the singular treatments; BMP4, WNT3A and LH were without effect. IGF1 amplified the stimulatory effect of FGF9 on E2F8 mRNA abundance by 2.7-fold. Collectively, our studies show for the first time that follicular E2F8 is developmentally and hormonally regulated indicating that E2F8 may be involved in follicular development.

The effects of flutamide on the neonatal rat hypothalamic-pituitary-adrenal and gonadal axes in response to hypoxia

Hypoxia is common with preterm birth and may lead to long-term effects on the adult hypothalamic-pituitary-adrenal (HPA) axis that are sexually dimorphic due to neonatal androgens. Although the adult rat adrenal does not express appreciable CYP17 activity, the neonatal rat adrenal may synthesize androgens that could be a critical local factor in the development of adrenal function. We evaluated these phenomena by pretreating the neonatal rats on postnatal days (PD) 1, 6, 13, 20 with flutamide (a nonsteroidal androgen receptor antagonist) at a standard or a high dose (10 mg/kg or 50 mg/kg) compared to vehicle control. One day later, neonatal rats were exposed to acute hypoxia and blood was sampled. We found that (a) in PD2 pups, flutamide augmented corticosterone responses in a sexually dimorphic pattern and without an increase in ACTH, (b) PD7 and PD14 pups had the smallest corticosterone response to hypoxia (c) PD21 pups had an adult-like corticosterone response to hypoxia that was sexually dimorphic, (d) flutamide attenuated ACTH responses in PD7 hypoxic pups, and (e) high-dose flutamide suppressed the HPA axis, FSH, and estradiol. Flutamide demonstrated mixed antagonist and agonist effects that changed during the first three weeks of neonatal life. We conclude that the use of flutamide in neonatal rats to evaluate androgen-induced programming of subsequent adult behavior is not optimal. However, our studies suggest neonatal androgens play a role in regulation of adrenal function that is sexually dimorphic and changes during early development.

Vascular endothelial growth factor A isoforms modulate follicle development in peripubertal heifers independent of diet through diverse signal transduction pathways

Follicular progression during peripuberty is affected by diet. Vascular endothelial growth factor A (VEGFA) induces follicle progression in many species; however, there are limited studies to determine if diet may alter the effects of angiogenic VEGFA165-stimulated follicle progression or antiangiogenic VEGFA165b follicle arrest. We hypothesized that diet affects the magnitude of angiogenic and antiangiogenic VEGFA isoform actions on follicular development through diverse signal transduction pathways. To test this hypothesis, beef heifers in our first trial received Stair-Step (restricted and refeeding) or control diets from 8 to 13 months of age. Ovaries were collected to determine follicle stages, measure vascular gene expression and conduct ovarian cortical cultures. Ovarian cortical cultures were treated with phosphate-buffered saline (control), 50 ng/ml VEGFA165, VEGFA165b, or VEGFA165 + VEGFA165b. The Stair-Step heifers had more primordial follicles (P &lt; 0.0001), greater messenger RNA abundance of vascular markers VE-cadherin (P &lt; 0.0001) and NRP-1 (P &lt; 0.0051) than controls at 13 months of age prior to culture. After culture, VEGFA isoforms had similar effects, independent of diet, where VEGFA165 stimulated and VEGFA165b inhibited VEGFA165-stimulated follicle progression from early primary to antral follicle stages. In vitro cultures were treated with VEGFA isoforms and signal transduction array plates were evaluated. VEGFA165 stimulated expression of genes related to cell cycle, cell proliferation, and growth while VEGFA165b inhibited expression of those genes. Thus, VEGFA isoforms can act independently of diet to alter follicle progression or arrest. Furthermore, follicle progression can be stimulated by VEGFA165 and inhibited by VEGFA165b through diverse signal transduction pathways.

Hormonal regulation of vascular endothelial growth factor A (VEGFA) gene expression in granulosa and theca cells of cattle1

Vascular endothelial growth factor A (VEGFA) stimulates angiogenesis and is associated with increased vascularity in ovarian follicles of cattle. The objectives of this study were to investigate the developmental and hormonal regulation of VEGFA expression in ovarian granulosa and theca cells (TC) of cattle. Bovine ovaries were collected from a local slaughterhouse and granulosa cells (GC) and TC were collected from small (SM; 1 to 5 mm) and large (LG; 8 to 20 mm) follicles. Cells were collected fresh or cultured in serum-free medium and treated with various factors that regulate angiogenesis and follicular development. RNA was collected for analysis of VEGFA mRNA abundance via quantitative PCR. In SM-follicle GC (SMGC), prostaglandin E2 (PGE2) and FSH decreased (P < 0.05) VEGFA mRNA abundance by 30 to 46%, whereas in LG-follicle GC (LGGC), PGE2 and FSH were without effect (P > 0.10). In SMGC, dihydrotestosterone (DHT), sonic hedgehog (SHH), and growth differentiation factor-9 (GDF9) decreased (P < 0.05) VEGFA expression by 30 to 40%. Fibroblast growth factor-9 (FGF9) and estradiol (E2) were without effect (P > 0.10) on VEGFA mRNA in both SMGC and LGGC, whereas progesterone increased (P < 0.05) VEGFA mRNA in LGGC but had no effect in LGTC. Bone morphogenetic protein-4 (BMP4), LH, and FGF9 increased (P < 0.05) abundance of VEGFA mRNA by 1.5- to 1.9-fold in LGTC. Insulin-like growth factor-1 (IGF1) was without effect (P > 0.10) on VEGFA mRNA in both TC and GC. An E2F transcription factor inhibitor, HLM0064741 (E2Fi), dramatically (i.e., 8- to 13-fold) stimulated (P < 0.01) the expression of VEGFA mRNA expression in both SMGC and LGTC. Abundance of VEGFA mRNA was greater (P < 0.05) in LGGC and SMGC than in LGTC. Also, SMTC had greater (P < 0.05) abundance of VEGFA mRNA than LGTC. In conclusion, VEGFA mRNA abundance was greater in GC than TC, and VEGFA expression decreased in TC during follicle development. Some treatments either suppressed, stimulated, or had no effect on VEGFA expression depending on the cell type. The inhibition of E2F transcription factors had the greatest stimulatory effect of all treatments evaluated, and thus, E2Fs may play an important role in regulating angiogenesis during follicle growth in cattle.

Comparative analysis of differentially expressed genes between the ovaries from pregnant and nonpregnant goats using RNA-Seq

Background

A multitude of genes tightly regulate ovarian follicular development and hormone secretion. These complex and coordinated biological processes are altered during pregnancy. In order to further understand the regulatory role of these genes during pregnancy, it is important to screen the differentially expressed genes (DEGs) in the ovaries of pregnant and nonpregnant mammals. To detect the genes associated with the development of pregnancy in goats, DEGs from the ovaries from pregnant and nonpregnant Anhui white goats (pAWGs and nAWGs, respectively) were analyzed using RNA sequencing technology (RNA-Seq).

Results

In this study, 13,676,394 and 13,549,560 clean reads were generated from pAWGs and nAWGs, respectively, and 1724 DEGs were identified between the two libraries. Compared with nAWGs, 1033 genes were upregulated and 691 genes were downregulated in pAWGs, including PGR, PRLR, STAR and CYP19A1, which play important roles in goat reproduction. Gene Ontology analysis showed that the DEGs were enriched for 49 functional GO terms. Kyoto Encyclopedia of Genes and Genomes analysis revealed that 397 DEGs were significantly enriched in 13 pathways, including “cell cycle”, “cytokine–cytokine receptor interaction” and “steroid biosynthesis”, suggesting that the genes may be associated with cell cycle regulation, follicular development and hormone secretion to regulate the reproduction process. Additionally, quantitative real-time PCR was used to verify the reliability of the RNA-Seq data.

Conclusions

The data obtained in this work enrich the genetic resources of goat and provide a further understanding of the complex molecular regulatory mechanisms occurring during the development of pregnancy and reproduction in goats. The DEGs screened in this study may play an important role in follicular development and hormone secretion and they would provide scientific basis for related research in the future.

Electronic supplementary material

The online version of this article (10.1186/s40709-019-0095-9) contains supplementary material, which is available to authorized users.

Regulatory roles of ephrinA5 and its novel signaling pathway in mouse primary granulosa cell apoptosis and proliferation

Recent findings suggest that ephrinA5 (Efna5) has a novel role in female mouse fertility, in addition to its well-defined role as a neurogenesis factor. Nevertheless, its physiological roles in ovarian granulosa cells (GC) have not been determined. In this study, mouse GC were cultured and transfected with ephrin A5 siRNA and negative control to determine the effects of Efna5 on GC apoptosis, proliferation, cell cycle progression, and related signaling pathways. To understand the mode signaling, the mRNA expression levels of Efna5 receptors (Eph receptor A5, Eph receptor A3, Eph receptor A8, and Eph receptor B2) were examined. Both mRNA and protein expressions of apoptosis-related factors (Bax, Bcl-2, Caspase 8, Caspase 3, and Tnfα) and a proliferation marker, Pcna, were investigated. Additionally, the role of Efna5 on paracrine oocyte-secreted factors and steroidogenesis hormones were also explored. Efna5 silencing suppressed GC apoptosis by downregulating Bax and upregulating Bcl-2 in a Caspase 8-dependent manner. Efna5 knockdown promoted GC proliferation via p-Akt and p-ERK pathway activation. The inhibition of Efna5 enhanced BMH15 and estradiol expression, but suppressed GDF9, while progesterone level remained unaltered. These results demonstrated that Efna5 is a pro-apoptotic agent in GC and plays important role in folliculogenesis by mediating apoptosis, proliferation, and steroidogenesis in female mouse. Therefore Efna5 might be potential therapeutic target for female fertility disorders.

Ovarian Follicular Theca Cell Recruitment, Differentiation, and Impact on Fertility: 2017 Update

The major goal of this review is to summarize recent exciting findings that have been published within the past 10 years that, to our knowledge, have not been presented in detail in previous reviews and that may impact altered follicular development in polycystic ovarian syndrome (PCOS) and premature ovarian failure in women. Specifically, we will cover the following: (1) mouse models that have led to discovery of the derivation of two precursor populations of theca cells in the embryonic gonad; (2) the key roles of the oocyte-derived factor growth differentiation factor 9 on the hedgehog (HH) signaling pathway and theca cell functions; and (3) the impact of the HH pathway on both the specification of theca endocrine cells and theca fibroblast and smooth muscle cells in developing follicles. We will also discuss the following: (1) other signaling pathways that impact the differentiation of theca cells, not only luteinizing hormone but also insulinlike 3, bone morphogenic proteins, the circadian clock genes, androgens, and estrogens; and (2) theca-associated vascular, immune, and fibroblast cells, as well as the cytokines and matrix factors that play key roles in follicle growth. Lastly, we will integrate what is known about theca cells from mouse models, human-derived theca cell lines from patients who have PCOS and patients who do not have PCOS, and microarray analyses of human and bovine theca to understand what pathways and factors contribute to follicle growth as well as to the abnormal function of theca.

Deletion of Arid1a in Reproductive Tract Mesenchymal Cells Reduces Fertility in Female Mice

Women with endometriosis can suffer from decreased fecundity or complete infertility via abnormal oocyte function or impaired placental-uterine interactions required for normal pregnancy establishment and maintenance. Although AT-rich interactive domain 1A (SWI-like) (ARID1A) is a putative tumor suppressor in human endometrial cancers and endometriosis-associated ovarian cancers, little is known about its role in normal uterine function. To study the potential function of ARID1A in the female reproductive tract, we generated mice with a conditional knockout of Arid1a using anti-Müllerian hormone receptor 2-Cre. Female Arid1a conditional knockout mice exhibited a progressive decrease in number of pups per litter, with a precipitous decline after the second litter. We observed no tumors in virgin mice, although one knockout mouse developed a uterine tumor after pregnancy. Unstimulated virgin female knockout mice showed normal oviductal, ovarian, and uterine histology. Uteri of Arid1a knockout mice showed a normal decidualization response and appropriate responses to estradiol and progesterone stimulation. In vitro studies using primary cultures of human endometrial stromal fibroblasts revealed that small interfering RNA knockdown of ARID1A did not affect decidualization in vitro. Timed pregnancy studies revealed the significant resorption of embryos at Embryonic Day 16.5 in knockout mice in the third pregnancy. In addition to evidence of implantation site hemorrhage, pregnant Arid1a knockout mice showed abnormal placental morphology. These results suggest that Arid1a supports successful pregnancy through its role in placental function.