CCAAT/enhancer-binding proteins (C/EBP)-α and -β are essential for ovulation, luteinization, and the expression of key target genes

Heterozygous Eif4nif1 Stop Gain Mice Replicate the Primary Ovarian Insufficiency Phenotype in Women

We created the c.1286C>G stop-gain mutation found in a family with primary ovarian insufficiency (POI) at age 30 years. The Eif4enif1 C57/Bl6 transgenic mouse model contained a floxed exon 10-19 cassette with a conditional knock-in cassette containing the c.1286C>G stop-gain mutation in exon 10. The hybrid offspring of CMV- Cre mice with Eif4enif1 WT/flx mice were designated Eif4enif1 WT/ Δ for simplicity. A subset of female heterozygotes ( Eif4enif1 WT/ Δ ) had no litters. In those with litters, the final litter was earlier (5.4±2.6 vs. 10.5±0.7 months; p=0.02). Heterozygous breeding pair ( Eif4enif1 WT/ Δ x Eif4enif1 WT/ Δ ) litter size was 60% of WT litter size (3.9±2.0 vs. 6.5±3.0 pups/litter; p <0.001). The genotypes were 35% Eif4enif1 WT/flx and 65% Eif4enif1 WT/ Δ , with no homozygotes. Homozygote embryos did not develop beyond the 4-8 cell stage. The number of follicles in ovaries from Eif4enif1 WT/ Δ mice was lower starting at the primordial (499±290 vs. 1445±381) and primary follicle stage (1069±346 vs. 1450±193) on day 10 (p<0.05). The preantral follicle number was lower starting on day 21 (213±86 vs. 522±227; p<0.01). Examination of ribosome protected mRNAs (RPR) demonstrated altered mRNA expression. The Eif4enif1 stop-gain mice replicate the POI phenotype in women. The unique mouse model provides a platform to study regulation of protein translation across oocyte and embryo development in mammals.

GRIM19 deficiency aggravates metabolic disorder and ovarian dysfunction in PCOS

CONTEXT

Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders in women. Retinoid-interferon-induced mortality 19 (GRIM19) is a functional component of mitochondrial complex I that plays a role in cellular energy metabolism. However, the role of GRIM19 in the pathogenesis of PCOS is still unclear.

OBJECTIVE

To investigate the role of GRIM19 in the pathogenesis of PCOS.

DESIGN

We first measured the expression of GRIM19 in human granulosa cells (hGCs) from patients with and without PCOS (n = 16 per group), and then established a PCOS mouse model with WT and Grim19+/- mice for in vivo experiments. Glucose uptake-related genes RAC1 and GLUT4 and energy metabolism levels in KGN cells were examined in vitro by knocking down GRIM19 in the cell lines. Additionally, ovulation-related genes such as p-ERK1/2, HAS2, and PTX3 were also studied to determine their expression levels.

RESULTS

GRIM19 expression was reduced in hGCs of PCOS patients, which was negatively correlated with BMI and serum testosterone level. Grim19+/- mice with PCOS exhibited a markedly anovulatory phenotype and disturbed glycolipid metabolism. In vitro experiments, GRIM19 deficiency inhibited the RAC1/GLUT4 pathway, reducing insulin-stimulated glucose uptake in KGN cells. Moreover, GRIM19 deficiency induced mitochondrial dysfunction, defective glucose metabolism, and apoptosis. In addition, GRIM19 deficiency suppressed the expression of ovulation-related genes in KGN cells, which was regulated by dihydrotestosterone mediated androgen receptor.

CONCLUSIONS

GRIM19 deficiency may mediate ovulation and glucose metabolism disorders in PCOS patients. Our results suggest that GRIM19 may be a new target for diagnosis and treatment.

Melatonin alleviates the toxic effect of di(2-ethylhexyl) phthalate on oocyte quality resulting from CEBPB suppression during primordial follicle formation

Presently, the exposure of plasticizers to humans and animals occurs daily, which pose a potential threat to reproductive health. In the present study, a pregnant mouse model exposed to di(2-ethylhexyl) phthalate (DEHP, one of the most common plasticizers) and melatonin was established, and the single-cell transcriptome technology was applied to investigate the effects of melatonin in ovarian cells against DEHP. Results showed that DEHP markedly altered the gene expression pattern of ovarian cells, and severely weakened the histone methylation modification of oocytes. The administration of melatonin recovered the expression of LHX8 and SOHLH1 proteins that essential for primordial follicle formation, and increased the expression of CEBPB, as well as key genes of histone methylation modification (such as Smyd3 and Kdm5a). In addition, the ovarian damage caused by DEHP was also relieved after the overexpression of CEBPB, which suggested melatonin could improve primordial follicle formation progress via enhancing CEBPB expression in mice. Besides, the apoptosis of ovarian cells induced by DEHP also was diminished by melatonin. The study provides evidence of melatonin preventing the damage mediated by plasticizers on the reproductive system in females and CEBPB may serve as a downstream target factor of melatonin in the process.

Transcriptomic signature of luteinized cumulus cells of oocytes developing to live birth after women received intracytoplasmic sperm injection

OBJECTIVE

To compare the transcriptome of human cumulus cells (CCs) from oocytes with different outcomes (pregnancy yes/no, live birth [LB] yes/no), to identify noninvasive biomarkers for oocyte selection as well as new therapeutic targets to increase LB rates from assisted reproductive technologies (ART).

DESIGN

Retrospective observational study.

SETTINGS

This study was conducted at a University Hospital in Switzerland.

PATIENTS

Subfertile couples undergoing controlled ovarian superstimulation and intracytoplasmic sperm injection with subsequent unbiopsied embryo transfer below the female age of 43 years.

INTERVENTION(S)

RNA sequencing of CCs from oocytes results in a pregnancy, no pregnancy, LB, or no LB.

MAIN OUTCOME MEASURES

Differential gene expression (DEG) between CCs of oocytes results in "no pregnancy" vs. "pregnancy" and "pregnancy only" vs. "live birth."

RESULTS

Although RNA sequencing did not reveal DEGs when comparing the transcriptomic profiles of the groups "no pregnancy" with "pregnancy," we identified 139 DEGs by comparing "pregnancy only" with "live birth," of which 28 belonged to clusters relevant to successful ART outcomes (i.e., CTGF, SERPINE2, PCK1, HHIP, HS3ST, and BIRC5). A functional enrichment analysis revealed that the transcriptome of CCs associated with LB depicts pathways of extracellular matrix, inflammatory cascades leading to ovulation, cell patterning, proliferation, and differentiation, and silencing pathways leading to apoptosis.

CONCLUSION

We identified a CCs transcriptomic profile associated with LB after embryo transfer that, after further validation, could serve to predict successful ART outcomes. The definition of relevant pathways of CCs related to oocyte competency contributes to a broader understanding of the cumulus oocyte complex and helps identify further therapeutic targets for improving ART success.

Ovarian ERβ cistrome and transcriptome reveal chromatin interaction with LRH-1

BACKGROUND

Estrogen receptor beta (ERβ, Esr2) plays a pivotal role in folliculogenesis and ovulation, yet its exact mechanism of action is mainly uncharacterized.

RESULTS

We here performed ERβ ChIP-sequencing of mouse ovaries followed by complementary RNA-sequencing of wild-type and ERβ knockout ovaries. By integrating the ERβ cistrome and transcriptome, we identified its direct target genes and enriched biological functions in the ovary. This demonstrated its strong impact on genes regulating organism development, cell migration, lipid metabolism, response to hypoxia, and response to estrogen. Cell-type deconvolution analysis of the bulk RNA-seq data revealed a decrease in luteal cells and an increased proportion of theca cells and a specific type of cumulus cells upon ERβ loss. Moreover, we identified a significant overlap with the gene regulatory network of liver receptor homolog 1 (LRH-1, Nr5a2) and showed that ERβ and LRH-1 extensively bound to the same chromatin locations in granulosa cells. Using ChIP-reChIP, we corroborated simultaneous ERβ and LRH-1 co-binding at the ERβ-repressed gene Greb1 but not at the ERβ-upregulated genes Cyp11a1 and Fkbp5. Transactivation assay experimentation further showed that ERβ and LRH-1 can inhibit their respective transcriptional activity at classical response elements.

CONCLUSIONS

By characterizing the genome-wide endogenous ERβ chromatin binding, gene regulations, and extensive crosstalk between ERβ and LRH-1, along with experimental corroborations, our data offer genome-wide mechanistic underpinnings of ovarian physiology and fertility.

ERK1/2-SOX9/FOXL2 axis regulates ovarian steroidogenesis and favors the follicular-luteal transition

Estradiol and progesterone are the primary sex steroids produced by the ovary. Upon luteinizing hormone surge, estradiol-producing granulosa cells convert into progesterone-producing cells and eventually become large luteal cells of the corpus luteum. Signaling pathways and transcription factors involved in the cessation of estradiol and simultaneous stimulation of progesterone production in granulosa cells are not clearly understood. Here, we decipher that phosphorylated ERK1/2 regulates granulosa cell steroidogenesis by inhibiting estradiol and inducing progesterone production. Down-regulation of transcription factor FOXL2 and up-regulation of SOX9 by ERK underpin its differential steroidogenic function. Interestingly, the incidence of SOX9 is largely uncovered in ovarian cells and is found to regulate FOXL2 along with CYP19A1 and STAR genes, encoding rate-limiting enzymes of steroidogenesis, in cultured granulosa cells. We propose that the novel ERK1/2-SOX9/FOXL2 axis in granulosa cells is a critical regulator of ovarian steroidogenesis and may be considered when addressing pathophysiologies associated with inappropriate steroid production and infertility in humans and animals.

Sepsis-induced endothelial dysfunction drives acute-on-chronic liver failure through Angiopoietin-2-HGF-C/EBPβ pathway

BACKGROUND AND AIMS

Acute-on-chronic liver failure (ACLF) is an acute liver and multisystem failure in patients with previously stable cirrhosis. A common cause of ACLF is sepsis secondary to bacterial infection. Sepsis-associated ACLF involves a loss of differentiated liver function in the absence of direct liver injury, and its mechanism is unknown. We aimed to study the mechanism of sepsis-associated ACLF using a novel mouse model.

APPROACH AND RESULTS

Sepsis-associated ACLF was induced by cecal ligation and puncture procedure (CLP) in mice treated with thioacetamide (TAA). The combination of TAA and CLP resulted in a significant decrease in liver synthetic function and high mortality. These changes were associated with reduced metabolic gene expression and increased CCAAT enhancer binding protein beta (C/EBPβ) transcriptional activity. We found that C/EBPβ binding to its target gene promoters was increased. In humans, C/EBPβ chromatin binding was similarly increased in the ACLF group compared with control cirrhosis. Hepatocyte-specific Cebpb knockout mice had reduced mortality and increased gene expression of hepatocyte differentiation markers in TAA/CLP mice, suggesting that C/EBPβ promotes liver failure in these mice. C/EBPβ activation was associated with endothelial dysfunction, characterized by reduced Angiopoietin-1/Angiopoietin-2 ratio and increased endothelial production of HGF. Angiopoietin-1 supplementation or Hgf knockdown reduced hepatocyte C/EBPβ accumulation, restored liver function, and reduced mortality, suggesting that endothelial dysfunction induced by sepsis drives ACLF through HGF-C/EBPβ pathway.

CONCLUSIONS

The transcription factor C/EBPβ is activated in both mouse and human ACLF and is a potential therapeutic target to prevent liver failure in patients with sepsis and cirrhosis.

Progesterone receptor mediates ovulatory transcription through RUNX transcription factor interactions and chromatin remodelling

Progesterone receptor (PGR) plays diverse roles in reproductive tissues and thus coordinates mammalian fertility. In the ovary, rapid acute induction of PGR is the key determinant of ovulation through transcriptional control of a unique set of genes that culminates in follicle rupture. However, the molecular mechanisms for this specialized PGR function in ovulation is poorly understood. We have assembled a detailed genomic profile of PGR action through combined ATAC-seq, RNA-seq and ChIP-seq analysis in wildtype and isoform-specific PGR null mice. We demonstrate that stimulating ovulation rapidly reprograms chromatin accessibility in two-thirds of sites, correlating with altered gene expression. An ovary-specific PGR action involving interaction with RUNX transcription factors was observed with 70% of PGR-bound regions also bound by RUNX1. These transcriptional complexes direct PGR binding to proximal promoter regions. Additionally, direct PGR binding to the canonical NR3C motif enable chromatin accessibility. Together these PGR actions mediate induction of essential ovulatory genes. Our findings highlight a novel PGR transcriptional mechanism specific to ovulation, providing new targets for infertility treatments or new contraceptives that block ovulation.

Ovulatory signal-triggered chromatin remodeling in ovarian granulosa cells by HDAC2 phosphorylation activation-mediated histone deacetylation

BACKGROUND

Epigenetic reprogramming is involved in luteinizing hormone (LH)-induced ovulation; however, the underlying mechanisms are largely unknown.

RESULTS

We here observed a rapid histone deacetylation process between two waves of active transcription mediated by the follicle-stimulating hormone (FSH) and the LH congener human chorionic gonadotropin (hCG), respectively. Analysis of the genome-wide H3K27Ac distribution in hCG-treated granulosa cells revealed that a rapid wave of genome-wide histone deacetylation remodels the chromatin, followed by the establishment of specific histone acetylation for ovulation. HDAC2 phosphorylation activation coincides with histone deacetylation in mouse preovulatory follicles. When HDAC2 was silenced or inhibited, histone acetylation was retained, leading to reduced gene transcription, retarded cumulus expansion, and ovulation defect. HDAC2 phosphorylation was associated with CK2α nuclear translocation, and inhibition of CK2α attenuated HDAC2 phosphorylation, retarded H3K27 deacetylation, and inactivated the ERK1/2 signaling cascade.

CONCLUSIONS

This study demonstrates that the ovulatory signal erases histone acetylation through activation of CK2α-mediated HDAC2 phosphorylation in granulosa cells, which is an essential prerequisite for subsequent successful ovulation.

MitoQ Protects Ovarian Organoids against Oxidative Stress during Oogenesis and Folliculogenesis In Vitro

Ovarian organoids, based on mouse female germline stem cells (FGSCs), have great value in basic research and are a vast prospect in pre-clinical drug screening due to their properties, but the competency of these in vitro-generated oocytes was generally low, especially, in vitro maturation (IVM) rate. Recently, it has been demonstrated that the 3D microenvironment triggers mitochondrial dysfunction during follicle growth in vitro. Therefore, therapies that protect mitochondria and enhance their function in oocytes warrant investigation. Here, we reported that exposure to 100 nM MitoQ promoted follicle growth and maturation in vitro, accompanied by scavenging ROS, reduced oxidative injury, and restored mitochondrial membrane potential in oocytes. Mechanistically, using mice granulosa cells (GCs) as a cellular model, it was shown that MitoQ protects GCs against H₂O₂-induced apoptosis by inhibiting the oxidative stress pathway. Together, these results reveal that MitoQ reduces oxidative stress in ovarian follicles via its antioxidative action, thereby protecting oocytes and granulosa cells and providing an efficient way to improve the quality of in vitro-generated oocytes.

Decreased Expression of EZH2 in Granulosa Cells Contributes to Endometriosis-Associated Infertility by Targeting IL-1R2

The mechanism by which endometriosis, a common gynecological disease characterized by chronic pelvic pain and infertility, causes infertility remains elusive. Luteinized unruptured follicle syndrome, the most common type of ovulatory dysfunction, is a cause of endometriosis-associated infertility involving reduced numbers of retrieved and mature oocytes. Ovulation is controlled by luteinizing hormone and paracrine signals produced within the follicle microenvironment. Generally, interleukin (IL)-1β is elevated in endometriosis follicular fluid, whereby it amplifies ovulation signals by activating extracellular-regulated kinase 1/2 and CCAAT/enhancer binding protein β pathways. However, this amplification of ovulation by IL-1β does not occur in patients with endometriosis. To illuminate the mechanism of ovulatory dysfunction in endometriosis, we analyzed the effect of oxidative stress and IL-1β expression on endometriosis follicles. We found that oxidative stress decreased EZH2 expression and reduced H3K27Me3 levels in endometriosis ovarian granulosa cells (GCs). Selective Ezh2 depletion in mice ovarian GCs reduced fertility by disturbing cumulus-oocyte complex expansion and reducing epidermal growth factor-like factor expression. Gene expression and H3K27Me3 ChIP-sequencing (ChIP-Seq) of GCs revealed IL-1 receptor 2 (IL-1R2), a high-affinity IL-1β-receptor that suppresses IL-1β-mediated inflammatory cascades during ovulation, as a crucial target gene of the EZH2-H3K27Me3 axis. Moreover, IL-1β addition did not restore ovulation upon Ezh2 knockdown, indicating a vital function of IL-1R2 in endometriosis. Thus, our findings show that reducing EZH2 and H3K27Me3 in GCs suppressed ovulatory signals by increasing IL-1R2 expression, which may ultimately contribute to endometriosis-associated infertility.

Lipopolysaccharide alters CEBPβ signaling and reduces estradiol production in bovine granulosa cells

Background

Bacterial infection of the uterus in postpartum dairy cows limits ovarian follicle growth, reduces blood estradiol concentrations, and leads to accumulation of bacterial lipopolysaccharide (LPS) in ovarian follicular fluid. Although treating granulosa cells with LPS in vitro decreases the expression of the estradiol synthesis enzyme CYP19A1 and reduces estradiol secretion, the molecular mechanisms are unclear. The transcription factor CCAAT enhancer binding protein beta (CEBPβ) not only facilitates the transcription of LPS regulated cytokines, but also binds to the promoter region of CYP19A1 in humans, mice, and buffalo. We hypothesized that LPS alters CEBPβ signaling to reduce CYP19A1 expression, resulting in decreased estradiol secretion.

Methods

Bovine granulosa cells were isolated from small/medium or large follicles and treated with LPS in the presence of FSH and androstenedione for up to 24 h.

Results

Treatment with LPS increased CXCL8 and IL6 gene expression and reduced estradiol secretion in granulosa cells from both small/medium and large follicles. However, LPS only reduced CYP19A1 expression in granulosa cells from large follicles. Treatment with LPS increased CEBPB expression and reduced CEBPβ nuclear localization in granulosa cells from small/medium follicles, but not granulosa cells from large follicles.

Conclusions

Although LPS reduces estradiol synthesis in bovine granulosa cells, the effects of LPS on CYP19A1 and CEBPβ are dependent on follicle size.

Signal pathway of LH-induced expression of nuclear progestin receptor in vertebrate ovulation

Nuclear progestin receptor (PGR), which is induced in the follicles destined to undergo ovulation, is believed to be obligatory for rupture of the follicles during ovulation in vertebrates. Studies in some mammals and teleost medaka have revealed the outline of the central signaling pathway that leads to the PGR expression in the preovulatory follicles at ovulation. In this review, we summarize the current knowledge on what signaling mediators are involved in the LH-induced follicular expression of PGR at ovulation in these animals. LH-inducibility of follicular PGR expression is conserved. In both group of animals, activation of the LH receptor on the granulosa cell surface with LH commonly results in the increase of intracellular cAMP levels, while the downstream signaling cascades activated by high level of cAMP are totally different between mice and medaka. PGR is currently presumed to be induced via PKA/CREB-mediated transactivation and ERK1/2-dependent signaling in mice, but the receptor is induced via EPAC/RAP and AKT/CREB pathways in the teleost medaka. The differences and similarities in the signaling pathways for PGR expression between them is discussed from comparative and evolutionary aspects. We also discussed questions concerning PGR expression and its regulation needed to be investigated in future.

Expression of Enhancer-Binding Protein CEBPA mRNA and Protein in Ovarian Cancer and Its Relationship With Pathobiological Characteristics

Ovarian cancer is a common malignant tumor, its early onset is hidden, lack of specific symptoms, the location of the lesion is particularly hidden, which makes it difficult to find ovarian lesions by general detection, making it difficult to make an early clinical diagnosis. Therefore, it is still the focus and difficulty of ovarian cancer research to find the means of early diagnosis and prognosis of ovarian cancer. Cytosine-cytosine-adenosine-adenosine-thymidine (CCAAT) enhancer-binding protein α (CEBPA) has been proved to be involved in cell metabolism, proliferation, and differentiation. In this study, the expression of CEBPA mRNA and protein in normal ovary, epithelial ovarian cyst, ovarian borderline tumor, and ovarian cancer was detected, the relationship between CEBPA and pathobiological characteristics of ovarian cancer was discussed, and its influence on the prognosis of patients with ovarian cancer was analyzed. The results showed that the expression of CEBPA mRNA and protein in patients with ovarian borderline tumor and ovarian cancer is high, and the expression of CEBPA has no obvious correlation with the pathobiological characteristics of patients with ovarian cancer, and the high expression of CEBPA has an important value in the diagnosis of ovarian cancer, and it is also a poor prognostic factor of the disease.

Downregulation of LHCGR Attenuates COX-2 Expression and Induces Luteinized Unruptured Follicle Syndrome in Endometriosis

An association between endometriosis and luteinized unruptured follicle syndrome (LUFs) has long been identified. Although inactivating mutation of luteinizing hormone/choriogonadotropin receptor (LHGCR) results in LUFs, whether LHCGR contributes to promoting LUFs in endometriosis remains elusive. To investigate the effect of LHCGR signaling in the development of endometriosis-associated LUFs and dissect the underlying mechanism in vivo mouse endometriosis model was established to measure the effect on ovarian folliculogenesis. In vitro cultures of primary human GCs collected from patients undergoing in vitro fertilization were performed and treated with human chorionic gonadotropin (hCG), dibutyryl cyclic-AMP (db-cAMP), LHCGR or CCAAT/enhancer binding protein-α (C/EBPα) small interfering RNA to identify the potential mechanisms. KGN cell line was used to investigate the mechanistic features of transcriptional regulation. Results showed an increased incidence of LUFs was observed in mice with endometriosis. The expression of LHCGR was decreased in the GCs of endometriosis mice. In in vitro cell models, LHCGR signaling increased the expression of C/EBPα and cyclooxygenase-2(COX-2), while inhibiting C/EBPα mitigated the induced COX-2 expression. Mechanically, C/EBPα bounded to the promoter region of COX-2 and increased the transcriptional activity under the stimulation of hCG or db-cAMP. Taken together, this study demonstrated that the LHCGR signaling was reduced in GCs of endometriosis and resulted in a decrease in gonadotropin-induced COX-2 expression. Our study might provide new insights into the dysfunction of GCs in endometriosis.

CNOT6/6L-mediated mRNA degradation in ovarian granulosa cells is a key mechanism of gonadotropin-triggered follicle development

CCR4-NOT deadenylase is a major regulator of mRNA turnover. It contains two heterogeneous catalytic subunits CNOT7/8 and CNOT6/6L in vertebrates. The physiological function of each catalytic subunit is unclear due to the gene redundancy. In this study, Cnot6/6l double knockout mice are generated. Cnot6l^-/- female mice are infertile, with poor ovarian responses to gonadotropins. Follicle-stimulating hormone (FSH) stimulates the transcription and translation of Cnot6 and Cnot6l in ovarian granulosa cells. CNOT6/6L function as key effectors of FSH in granulosa cells and trigger the clearance of specific transcripts in granulosa cells during preantral to antral follicle transition. These results demonstrate that FSH modulates granulosa cell function by stimulating selective translational activation and degradation of existing mRNAs, in addition to inducing de novo gene transcription. Meanwhile, this study provides in vivo evidence that CNOT6/6L-mediated mRNA deadenylation is dispensable in most somatic cell types, but is essential for female reproductive endocrine regulation.

The FOS/AP-1 Regulates Metabolic Changes and Cholesterol Synthesis in Human Periovulatory Granulosa Cells

FOS, a subunit of the activator protein-1 (AP-1) transcription factor, has been implicated in various cellular changes. In the human ovary, the expression of FOS and its heterodimeric binding partners JUN, JUNB, and JUND increases in periovulatory follicles. However, the specific role of the FOS/AP-1 remains elusive. The present study determined the regulatory mechanisms driving the expression of FOS and its partners and functions of FOS using primary human granulosa/lutein cells (hGLCs). Human chorionic gonadotropin (hCG) induced a biphasic increase in the expression of FOS, peaking at 1 to 3 hours and 12 hours. The levels of JUN proteins were also increased by hCG, with varying expression patterns. Coimmunoprecipitation analyses revealed that FOS is present as heterodimers with all JUN proteins. hCG immediately activated protein kinase A and p42/44MAPK signaling pathways, and inhibitors for these pathways abolished hCG-induced increases in the levels of FOS, JUN, and JUNB. To identify the genes regulated by FOS, high-throughput RNA sequencing was performed using hGLC treated with hCG ± T-5224 (FOS inhibitor). Sequencing data analysis revealed that FOS inhibition affects the expression of numerous genes, including a cluster of genes involved in the periovulatory process such as matrix remodeling, prostaglandin synthesis, glycolysis, and cholesterol biosynthesis. Quantitative PCR analysis verified hCG-induced, T-5224-regulated expression of a selection of genes involved in these processes. Consistently, hCG-induced increases in metabolic activities and cholesterol levels were suppressed by T-5224. This study unveiled potential downstream target genes of and a role for the FOS/AP-1 complex in metabolic changes and cholesterol biosynthesis in granulosa/lutein cells of human periovulatory follicles.

Integrated Analysis of Transcriptome and Histone Modifications in Granulosa Cells During Ovulation in Female Mice

The ovulatory luteinizing hormone (LH) surge induces rapid changes of gene expression and cellular functions in granulosa cells (GCs) undergoing luteinization. However, it remains unclear how the changes in genome-wide gene expression are regulated. H3K4me3 histone modifications are involved in the rapid alteration of gene expression. In this study, we investigated genome-wide changes of transcriptome and H3K4me3 status in mouse GCs undergoing luteinization. GCs were obtained from mice treated with equine chorionic gonadotropin (hCG) before, 4 hours, and 12 hours after human chorionic gonadotropin injection. RNA-sequencing identified a number of upregulated and downregulated genes, which could be classified into 8 patterns according to the time-course changes of gene expression. Many genes were transiently upregulated or downregulated at 4 hours after hCG stimulation. Gene Ontology terms associated with these genes included steroidogenesis, ovulation, cumulus-oocyte complex (COC) expansion, angiogenesis, immune system, reactive oxygen species (ROS) metabolism, inflammatory response, metabolism, and autophagy. The cellular functions of DNA repair and cell growth were newly identified as being activated during ovulation. Chromatin immunoprecipitation-sequencing revealed a genome-wide and rapid change in H3K4me3 during ovulation. Integration of transcriptome and H3K4me3 data identified many H3K4me3-associated genes that are involved in steroidogenesis, ovulation, COC expansion, angiogenesis, inflammatory response, immune system, ROS metabolism, lipid and glucose metabolism, autophagy, and regulation of cell size. The present results suggest that genome-wide changes in H3K4me3 after the LH surge are associated with rapid changes in gene expression in GCs, which enables GCs to acquire a lot of cellular functions within a short time that are required for ovulation and luteinization.

Propylparaben concentrations in the urine of women and adverse effects on ovarian function in mice in vivo and ovarian cells in vitro

Female reproduction is precisely regulated by hormones, and the ovary is easily affected by environmental endocrine disruptors (EDCs), which are ubiquitous in industrialized societies. Parabens are EDCs that are used as antibacterial preservatives in cosmetics, personal care products (PCPs), medicines, and food. We used ultrahigh-performance liquid chromatography-mass spectrometry to quantitatively detect methyl-, ethyl-, butyl-, and propylparaben (PP) concentrations in urine samples from 74 women of childbearing age. Balb/c mice were subcutaneously injected with 100 mg/kg/day of PP for 21 consecutive days or 100 or 1,000 mg/kg/day of PP during superovulation. Various concentrations of PP (ranging from 1 to 1,000 nM) were added to a human ovarian granulosa tumor-derived cell line (KGN) culture for 24 h. The urinary paraben concentrations of women who used cosmetics and other PCPs within 48 h prior to sample collection were significantly elevated, and the PP concentration was significantly positively correlated with the basal estradiol concentration. After PP injection, the mouse serum estradiol concentrations were significantly increased, estrus cycles were disordered, corpus luteum number was reduced, and number of oocytes retrieved was significantly reduced. In in vitro experiments, PP treatment increased estradiol synthesis and the expression levels of aromatase enzyme (CYP19A1) and steroidogenic acute regulatory protein. This study demonstrates the adverse effects of PP on ovarian estradiol secretion and ovulation, further evaluates the safety of PP as a preservative, and provides guidance for the use of PCPs and cosmetics by women of childbearing age.

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

OBJECTIVE

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

DESIGN

Xenotransplantation model.

SETTING

University-based research laboratory.

PATIENTS/ANIMALS

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

INTERVENTIONS

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

MAIN OUTCOME MEASURES

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

RESULTS

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

CONCLUSIONS

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

Addressing the role of 11β-hydroxysteroid dehydrogenase type 1 in the development of polycystic ovary syndrome and the putative therapeutic effects of its selective inhibition in a preclinical model

BACKGROUND

Polycystic ovary syndrome (PCOS) is the most common metabolic and endocrine disorder among reproductive-age women, and the leading cause of anovulatory infertility. 11β-hydroxysteroid dehydrogenases-1 (11β-HSD1) catalysing the conversion of inactive cortisone to active cortisol plays a crucial role in various metabolic diseases. However, whether 11β-HSD1 is associated with the pathogenesis of PCOS and whether 11β-HSD1 can be a treating target of PCOS remain unknown.

METHODS

This study was first designed to explore the role of 11β-HSD1 in PCOS development and the effect of selective 11β-HSD1 inhibitor administration on PCOS treatment. Follicular fluid and granulosa cells (GCs) were collected from 32 non-PCOS patients and 37 patients with PCOS to measure cortisol and 11β-HSDs levels. Female Sprague-Dawley rats (3-week-old) were injected with dehydroepiandrosterone (DHEA) to induce PCOS and their ovaries were collected to measure the abundance of corticosterone (CORT) and 11β-HSDs. To determine the role of 11β-HSD1 in PCOS development, we overexpressed 11β-HSD1 in the ovaries of female rats (5-week-old) or knocked down the expression of 11β-HSD1 in the ovaries from PCOS rats via lentivirus injection. After lentivirus infection, the body weights, ovarian weights, estrous cycles, reproductive hormones and morphology of the ovary were analysed in rats from different experimental groups. Then to figure out the translational potential of the selective 11β-HSD1 inhibitor in treating PCOS, PCOS rats were treated with BVT.2733, a selective 11β-HSD1 inhibitor and a cluster of PCOS-like traits were analysed, including insulin sensitivity, ovulatory function and fertility of rats from the Control, PCOS and PCOS+BVT groups. Rat ovarian explants and human GCs were used to explore the effect of CORT or cortisol on ovarian extracellular matrix remodelling.

RESULTS

The elevated expression of 11β-HSD1 contributed to the increased cortisol and corticosterone (CORT) concentrations observed in the ovaries of PCOS patients and PCOS rats respectively. Our results showed that ovarian overexpression of 11β-HSD1 induced a cluster of PCOS phenotypes in rats including irregular estrous cycles, reproductive hormone dysfunction and polycystic ovaries. While knockdown of ovarian 11β-HSD1 of PCOS rats reversed these PCOS-like changes. Additionally, the selective 11β-HSD1 inhibitor BVT.2733 alleviated PCOS symptoms such as insulin resistance (IR), irregular estrous cycles, reproductive hormone dysfunction, polycystic ovaries, ovulatory dysfunction and subfertility. Moreover, we showed that cortisol target ovarian insulin signalling pathway and ovarian extracellular matrix (ECM) remodelling in vivo, in ovarian explants and in GCs.

CONCLUSION

Elevated 11β-HSD1 abundance in ovarian is involved in the pathogenesis of PCOS by impairing insulin signalling pathway and ECM remodelling. Selective inhibition of 11β-HSD1 ameliorates a cluster of PCOS phenotypes. Our study demonstrates the selective 11β-HSD1 inhibitor as a novel and promising strategy for the treatment of PCOS.

Novel insights of acute myeloid leukemia with CEBPA deregulation: Heterogeneity dissection and re-stratification

Acute myeloid leukemia with bi-allelic CEBPA mutation was categorized as an independent disease entity with favorable prognosis, however, recent researches have revealed huge heterogeneity within this disease group, and for some patients, relapse remained a major cause of treatment failure. Further risk stratification is essentially needed. Here by reviewing the latest literature, we summarized the characteristics of CEBPA mutation profiles and clinical features, with a special intention of dissecting the heterogeneity within the seemingly homogeneous AML with bi-allelic CEBPA mutations. Specifically, non-classical CEBPA mutation, miscellaneous companion genetic aberrations and the presence of germline CEBPA mutation are three major sources of heterogeneity. Identifying these factors can help us predict patients at a higher risk of relapse, for whom aggressive treatment may be recommended. Novel therapeutic approaches regarding manipulating potentially druggable targets as well as the debate over post remission consolidation regimens has also been discussed.

Impact of Dietary Selenium on Modulation of Expression of Several Non-Selenoprotein Genes Related to Key Ovarian Functions, Female Fertility, and Proteostasis: a Transcriptome-Based Analysis of the Aging Mice Ovaries

Female reproductive (ovarian) aging is characterized by a marked decline in quantity and quality of follicles and oocytes, as well as alterations in the surrounding ovarian stroma. In our previous report, we have shown that dietary selenium (Se) insufficiency and supplementation differentially impacted the reproductive efficiency in aging mice; however, the precise understanding of such modulation is still incomplete. In the present study, we sought to determine the impact of low (mildly low level) and moderately high (medium level) Se diets on expression profile of non-selenoprotein genes in the ovaries of aging mice. For this purpose, the aged mice were divided in two groups and fed either a low Se (Se-L; 0.08 mg Se/kg) diet or a moderately high Se (Se-M; 0.33 mg Se/kg) diet. RNA-seq analysis revealed that a total of 168 genes were differentially expressed between the two groups. From these, 72 and 96 differentially expressed genes (DEGs) were found to be upregulated and downregulated, respectively. Gene Ontology (GO) and pathways enrichment (KEGG) analyses revealed that these DEGs were enriched in several key GO terms and biological pathways including PI3K-Akt signaling pathway, steroid hormone biosynthesis, signaling pathways regulating pluripotency of stem cells, Hippo signaling pathway, ovarian steroidogenesis, and Wnt signaling pathway. Further filtering of RNA-seq data revealed that several DEGs such as Star, Hsd3b6, Scd1, Bmp7, Aqp8, Gas1, Fzd1, and Wwc1 were implicated in key ovarian- and fertility-related functions. In addition, some of the DEGs were related to ER homeostasis and/or proteostasis. These results highlight that dietary low and moderately high (medium level) Se diets, in addition to modulation of selenoproteins, can also have an impact on expression of several non-selenoprotein genes in the ovaries of aging mice. To sum up, these findings add more value to our understanding of Se modulation of ovarian functions and female fertility and will pave a way for the focused mechanistic and functional studies in this domain.

Molecular Targets and Associated Signaling Pathways of Jingshu Granules in Ovarian Cysts Based on Systemic Pharmacological Analysis

Background

More than a third of women could develop ovarian cysts during their lifetime. Jingshu granules are used for the treatment of gynecological disease of primary dysmenorrhea. However, the molecular mechanisms of Jingshu granules in ovarian cysts are still unreported. We aimed to find the active ingredients, molecular targets, and potential signaling pathways of Jingshu granules in ovarian cysts by using the systemic pharmacological analysis.

Methods

Firstly, the effect of Jingshu granules on female hormones and reproductive organs of young female rats was evaluated. Secondly, candidate pharmaceutical ingredients of Jingshu granules were retrieved from the traditional Chinese medicine systems pharmacology (TCMSP) database and analysis platform. Potential protein targets for the active ingredients in Jingshu granules were then identified according to the oral bioavailability and drug-likeness indices. Thirdly, ovarian cyst-related gene targets were screened based on different databases. Finally, enrichment analysis was used to analyze the potential biological function of intersection targets between Jingshu granules and ovarian cysts.

Results

In young female rats, Jingshu granules reduced the secretion of estradiol, progesterone, and prolactin and could affect the development of the uterus. This suggested that Jingshu granules played roles in hormone secretion and reproduction. From the TCMSP, a total of 1021 pharmaceutical ingredients of Jingshu granules were retrieved. After further screening, a total of 166 active ingredients and 159 protein targets of Jingshu granules were identified. In addition, 4488 gene targets of ovarian cysts were screened out. After taking the intersection, a total of 110 intersection targets were identified between potential protein targets of Jingshu granules and gene targets of ovarian cysts. In the functional analysis of 110 intersection targets, 8 signaling pathways including progesterone-mediated oocyte maturation (MAPK8 and CDK1 involved), GnRH signaling pathway (JUN involved), T cell receptor signaling pathway and Toll-like receptor signaling pathway (MAPK1 involved), NOD-like receptor signaling pathway (TNF, IL6, and IL1B involved), p53 signaling pathway (CDK2 and CDK4 involved), VEGF signaling pathway (MAPK14 involved), and PPAR signaling pathway (PPARG involved) were obtained.

Conclusion

Our study revealed that Jingshu granules could function in patients with ovarian cysts through a number of molecular targets and signaling pathways. Our study may provide a new field into the mechanisms of Jingshu granules in ovarian cysts, from the molecular to the signaling pathway level.

Dissection of the Ovulatory Process Using ex vivo Approaches

Ovulation is a unique physiological phenomenon that is essential for sexual reproduction. It refers to the entire process of ovarian follicle responses to hormonal stimulation resulting in the release of mature fertilization-competent oocytes from the follicles and ovaries. Remarkably, ovulation in different species can be reproduced out-of-body with high fidelity. Moreover, most of the molecular mechanisms and signaling pathways engaged in this process have been delineated using in vitro ovulation models. Here, we provide an overview of the major molecular and cytological events of ovulation observed in frogs, primarily in the African clawed frog Xenopus laevis, using mainly ex vivo approaches, with the focus on meiotic oocyte maturation and follicle rupture. For the purpose of comparison and generalization, we also refer extensively to ovulation in other biological species, most notoriously, in mammals.

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

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

Quercetin alleviated H2 O2 -induced apoptosis and steroidogenic impairment in goat luteinized granulosa cells

Quercetin (Que) is a natural flavonoid in most plants. Luteinized granulosa cell (LGC) culture is necessary for the study of follicle growth/differentiation. In the present study, we analyzed the role of Que in steroid production and apoptosis in hydrogen peroxide (H2 O2 )-treated goat LGCs. The results showed that treatment with H2 O2 induced apoptosis in goat LGCs, and treatment with Que decreased LGC apoptosis induced by H2 O2 (P < .05), accompanied with the different expressions of BAX, BCL-2, Caspase 3, and Cleaved caspase 3. Meanwhile, the messenger RNA expressions of nuclear factor erythroid 2 like 2 (Nrf2) and its downstream genes were upregulated with H2 O2 +Que treatment, accompanied by the increased cellular viability (P < .05). Furthermore, Que alleviated H2 O2 -induced reduction in the secretion of progesterone (P4 ) (P < .05); however, it had no effect on the secretion of estrogen (E2 ). Simultaneously, the expressions of StAR and P450scc were increased when treated with Que +H2 O2 , compared with the group treated with only H2 O2 (P < .05). In conclusion, it is observed that Que could alleviate the H2 O2 -induced apoptosis and steroidogenic impairment in goat LGCs, which might be mediated by the Nrf2 pathway.

WOMEN IN REPRODUCTIVE SCIENCE: Discovering science and the ovary: a career of joy

My career has been about discovering science and learning the joys of the discovery process itself. It has been a challenging but rewarding process filled with many exciting moments and wonderful colleagues and students. Although I went to college to become a French major, I ultimately stumbled into research while pursuing a Masters Degree in teaching. Thus, my research career began in graduate school where I was studying NAD kinase in the ovary as a possible regulator of steroidogenesis, a big issue in the late 1960s. After a short excursion of teaching in North Dakota, I became a postdoctoral fellow at the University of Michigan, where radio-immuno assays and radio receptor assays had just come on the scene and were transforming endocrinology from laborious bioassays to quantitative science and of course these assays related to the ovary. From there I went to Baylor College of Medicine, a mecca of molecular biology, cloning genes and generating mouse models. It has been a fascinating and joyous journey.

CFP1-dependent histone H3K4 trimethylation in murine oocytes facilitates ovarian follicle recruitment and ovulation in a cell-nonautonomous manner

CxxC-finger protein 1 (CFP1)-mediated trimethylated histone H3 at lysine-4 (H3K4me3) during oocyte development enables the oocyte genome to establish the competence to generate a new organism. Nevertheless, it remains unclear to which extent this epigenetic modification forms an instructive component of ovarian follicle development. We investigated the ovarian functions using an oocyte-specific Cxxc1 knockout mouse model, in which the H3K4me3 accumulation is downregulated in oocytes of developing follicles. CFP1-dependent H3K4 trimethylation in oocytes was necessary to maintain the expression of key paracrine factors and to facilitate the communication between an oocyte and the surrounding granulosa cells. The distinct gene expression patterns in cumulus cells within preovulatory follicles were disrupted by the Cxxc1 deletion in oocytes. Both follicle growth and ovulation were compromised after CFP1 deletion, because Cxxc1 deletion in oocytes indirectly impaired essential signaling pathways in granulosa cells that mediate the functions of follicle-stimulating hormone and luteinizing hormone. Therefore, CFP1-regulated epigenetic modification of the oocyte genome influences the responses of ovarian follicles to gonadotropin in a cell-nonautonomous manner.

Erythropoietin-producing hepatocellular receptor A7 restrains estrogen negative feedback of luteinizing hormone via ephrin A5 in the hypothalamus of female rats

We have previously shown that systemic injection of erythropoietin-producing hepatocellular receptor A7 (EPHA7)-Fc raises serum luteinizing hormone (LH) levels before ovulation in female rats, indicating the induction of EPHA7 in ovulation. In this study, we aimed to identify the mechanism and hypothalamus-pituitary-ovary (HPO) axis level underlying the promotion of LH secretion by EPHA7. Using an ovariectomized (OVX) rat model, in conjunction with low-dose 17β-estradiol (E₂) treatment, we investigated the association between EPHA7-ephrin (EFN)A5 signaling and E₂ negative feedback. Various rat models (OVX, E₂-treated OVX, and abarelix treated) were injected with the recombinant EPHA7-Fc protein through the caudal vein to investigate the molecular mechanism underlying the promotion of LH secretion by EPHA7. Efna5 was observed strongly expressed in the arcuate nucleus of the female rat by using RNAscope in situ hybridization. Our results indicated that E₂, combined with estrogen receptor (ER)α, but not ERβ, inhibited Efna5 and gonadotropin-releasing hormone 1 (Gnrh1) expressions in the hypothalamus. In addition, the systemic administration of EPHA7-Fc restrained the inhibition of Efna5 and Gnrh1 by E₂, resulting in increased Efna5 and Gnrh1 expressions in the hypothalamus as well as increased serum LH levels. Collectively, our findings demonstrated the involvement of EPHA7-EFNA5 signaling in the regulation of LH and the E₂ negative feedback pathway in the hypothalamus, highlighting the functional role of EPHA7 in female reproduction.

Core Binding Factors are essential for ovulation, luteinization, and female fertility in mice

Core Binding Factors (CBFs) are a small group of heterodimeric transcription factor complexes composed of DNA binding proteins, RUNXs, and a non-DNA binding protein, CBFB. The LH surge increases the expression of Runx1 and Runx2 in ovulatory follicles, while Cbfb is constitutively expressed. To investigate the physiological significance of CBFs, we generated a conditional mutant mouse model in which granulosa cell expression of Runx2 and Cbfb was deleted by the Esr2Cre. Female Cbfbflox/flox;Esr2cre/+;Runx2flox/flox mice were infertile; follicles developed to the preovulatory follicle stage but failed to ovulate. RNA-seq analysis of mutant mouse ovaries collected at 11 h post-hCG unveiled numerous CBFs-downstream genes that are associated with inflammation, matrix remodeling, wnt signaling, and steroid metabolism. Mutant mice also failed to develop corpora lutea, as evident by the lack of luteal marker gene expression, marked reduction of vascularization, and excessive apoptotic staining in unruptured poorly luteinized follicles, consistent with dramatic reduction of progesterone by 24 h after hCG administration. The present study provides in vivo evidence that CBFs act as essential transcriptional regulators of both ovulation and luteinization by regulating the expression of key genes that are involved in inflammation, matrix remodeling, cell differentiation, vascularization, and steroid metabolisms in mice.

C/EBPß Isoform Specific Gene Regulation: It's a Lot more Complicated than you Think!

It has been almost 30 years since C/EBPß was discovered. Seminal studies have shown that C/EBPß is a master regulator of mammary gland development and has been shown to control and influence proliferation and differentiation through varying mechanisms. The single-exon C/EBPß mRNA yields at least three different protein isoforms which have diverse, specific, context-dependent, and often non-overlapping roles throughout development and breast cancer progression. These roles are dictated by a number of complex factors including: expression levels of other C/EBP family members and their stoichiometry relative to the isoform in question, binding site affinity, post-translational modifications, co-factor expression, and even hormone levels and lactogenic status. Here we summarize the historical work up to the latest findings in the field on C/EBPß in the mammary gland and in breast cancer. With the current emphasis on improving immunotherapy in breast cancer the role of specific C/EBPß isoforms in regulating specific chemokine and cytokine expression and the immune microenvironment will be of increasing interest.

Up-regulated FHL2 inhibits ovulation through interacting with androgen receptor and ERK1/2 in polycystic ovary syndrome

BACKGROUND

The ovulatory dysfunction mechanisms underlying polycystic ovary syndrome (PCOS) are not completely understood. There is no effective therapy for PCOS so far.

METHODS

We measured the expression of four and a half LIM domain 2 (FHL2) and other related-genes in human granulosa cells (hGCs) from patients with and without PCOS. To minimise the heterogeneity of patients with PCOS, we only included PCOS patients meeting all three criteria according to the revised Rotterdam consensus. The in vitro effects of FHL2 on ovulatory genes and the underlying mechanisms were examined in KGN cells. The role of FHL2 in ovulation was investigated in vivo by overexpressing FHL2 in rat ovaries via intrabursal lentivirus injection.

FINDINGS

Increased FHL2 and androgen receptor (AR) expression and decreased CCAAT/enhancer-binding protein β (C/EBPβ) expression were observed in hGCs from patients with PCOS. FHL2 inhibited the expression of ovulation-related genes, including phosphorylated ERK1/2, C/EBPβ, COX2 and HAS2 in KGN cells. It was partially by interacting with AR to act as its co-regulator to inhibit C/EBPβ expression and by binding to ERK1/2 to inhibit its phosphorylation. Moreover, FHL2 abundance in hGCs was positively correlated with the basal serum testosterone concentration of patients with PCOS, and dihydrotestosterone (DHT)-induced FHL2 upregulation was mediated by AR signalling in KGN cells. Additionally, lentiviral-mediated functional FHL2 overexpression in rat ovaries for 1 week contributed to an impaired superovulatory response, displaying decreased numbers of retrieved oocytes and a lower MII oocyte rate. 3-week FHL2 overexpression rat models without superovulation led to acyclicity and polycystic ovary morphology.

INTERPRETATION

Our findings provide novel insights into the mechanisms underlying the pathogenesis of PCOS, suggesting that FHL2 could be a potential treatment target for ovulatory obstacles in PCOS. FUND: National Key Research and Development Program of China, National Natural Science Foundation, National Institutes of Health project and Shanghai Commission of Science and Technology.

Identification of loci associated with conception rate in primiparous Holstein cows

BACKGROUND

Subfertility is a major issue facing the dairy industry as the average US Holstein cow conception rate (CCR) is approximately 35%. The genetics underlying the physiological processes responsible for CCR, the proportion of cows able to conceive and maintain a pregnancy at each breeding, are not well characterized. The objectives of this study were to identify loci, positional candidate genes, and transcription factor binding sites (TFBS) associated with CCR and determine if there was a genetic correlation between CCR and milk production in primiparous Holstein cows. Cows were bred via artificial insemination (AI) at either observed estrus or timed AI and pregnancy status was determined at day 35 post-insemination. Additive, dominant, and recessive efficient mixed model association expedited (EMMAX) models were used in two genome-wide association analyses (GWAA). One GWAA focused on CCR at first service (CCR1) comparing cows that conceived and maintained pregnancy to day 35 after the first AI (n = 494) to those that were open after the first AI (n = 538). The second GWAA investigated loci associated with the number of times bred (TBRD) required for conception in cows that either conceived after the first AI (n = 494) or repeated services (n = 472).

RESULTS

The CCR1 GWAA identified 123, 198, and 76 loci associated (P < 5 × 10- 08) in additive, dominant, and recessive models, respectively. The TBRD GWAA identified 66, 95, and 33 loci associated (P < 5 × 10- 08) in additive, dominant, and recessive models, respectively. Four of the top five loci were shared in CCR1 and TBRD for each GWAA model. Many of the associated loci harbored positional candidate genes and TFBS with putative functional relevance to fertility. Thirty-six of the loci were validated in previous GWAA studies across multiple breeds. None of the CCR1 or TBRD associated loci were associated with milk production, nor was their significance with phenotypic and genetic correlations to 305-day milk production.

CONCLUSIONS

The identification and validation of loci, positional candidate genes, and TFBS associated with CCR1 and TBRD can be utilized to improve, and further characterize the processes involved in cattle fertility.

Induction of tumor suppressor KCTD11 during periovulatory period in rat ovary

The tumor suppressor gene KCTD11 plays a critical role in cell proliferation, differentiation and invasion. The current study investigated the regulation and the spatiotemporal expression pattern of Kctd11 in the rat ovary during the periovulatory period. Ovaries, granulosa cells, or theca-interstitial cells were collected at various times after hCG administration using an established gonadotropin-primed immature rat model that induces follicular development and ovulation. Real-time quantitative PCR analysis revealed that mRNA for Kctd11 was significantly induced both in theca-intersititial and granulosa cells after hCG treatment although their temporal expression patterns differed. In situ hybridization analysis demonstrated that Kctd11 mRNA expression was induced in theca-intersititial cells at 6 h after hCG, and the expression remained elevated until 12 h after hCG. Kctd11 mRNA was stimulated in granulosa cells at 6 h and reached the highest expression at 12 h. There was negligible Kctd11 mRNA signal observed in newly forming corpora lutea. In addition, the data indicate that both the protein kinase A and the protein kinase C pathway regulate the expression of Kctd11 mRNA in granulosa cells. Either forskolin or phorbol 12 myristate 13-acetate can mimic hCG induction of Kctd11 expression. Furthermore, the stimulation of Kctd11 by hCG requires new protein synthesis. Inhibition of progesterone action and the EGF pathway blocked Kctd11 mRNA expression, whereas inhibition of prostaglandin synthesis had no effect. Our finding suggest that the induction of the Kctd11 may be important for theca and granulosa cell differentiation into luteal cells.

Mitogen-activated protein kinase kinase kinase 8 (MAP3K8) mediates the LH-induced stimulation of progesterone synthesis in the porcine corpus luteum

Progesterone (P4) synthesized by the corpus luteum (CL) plays a key role in the establishment and maintenance of pregnancy. The LH signal is important for luteinisation and P4 synthesis in pigs. In a previous study, we demonstrated that mitogen-activated protein kinase kinase kinase 8 (MAP3K8) regulates P4 synthesis in mouse CL, but whether the function and mechanism of MAP3K8 in the pig is similar to that in the mouse is not known. Thus, in the present study we investigated the effects of MAP3K8 on porcine CL. Abundant expression of MAP3K8 was detected in porcine CL, and, in pigs, MAP3K8 expression was higher in mature CLs (or those of the mid-luteal phase) than in regressing CLs (late luteal phase). Further functional studies in cultured porcine luteal cells showed that P4 synthesis and the expression of genes encoding the key enzymes in P4 synthesis are significantly reduced when MAP3K8 is inhibited with the MAP3K8 inhibitor Tpl2 kinase inhibitor (MAP3K8i, 10μM). After 12-24h treatment of luteal cells with 100ngmL-1 LH, MAP3K8 expression and P4 secretion were significantly upregulated. In addition, the 10μM MAP3K8 inhibitor blocked the stimulatory effect of LH on P4 synthesis and extracellular signal-regulated kinase (ERK) 1/2 phosphorylation in porcine luteal cells. The LH-induced increases in MAP3K8 phosphorylation and expression, ERK1/2 phosphorylation and P4 synthesis were all blocked when protein kinase A was inhibited by its inhibitor H89 (20 μM) in porcine luteal cells. In conclusion, MAP3K8 mediates the LH-induced stimulation of P4 synthesis through the PKA/mitogen-activated protein kinase signalling pathway in porcine CL.

3,3',4,4',5-Pentachlorobiphenyl influences mitochondrial apoptosis pathway in granulosa cells

3,3',4,4',5-Polychlorinated biphenyl (PCB126) is a persistent organic environmental pollutant which can affect various biological activities of organisms, such as immunity, neurological function, and reproduction. In our study, we aimed to investigate the effects of PCB126 on granulosa cells (GCs). GCs were collected from ovaries in PMSG-treated mice, after 24 hours culture. GCs were then incubated with 10 pg/mL, 100 pg/mL, and 10 ng/mL of PCB126 for another 24 hours. Following these steps, exposed GCs were collected for further experimentation. Our data showed that the number of GCs in the 10 ng/mL PCB126 decreased. Meanwhile, pyknotic nuclei and condensed chromatin increased, while the apoptotic cells in the 10 ng/mL PCB126 group were significantly increased. Furthermore, the expression of the apoptotic executive protein caspase-3 increased after PCB126 treatment. The expression of Bax, Bcl-2, and Bim related to the mitochondrial apoptosis pathway were also influenced to different degrees. Thus, our data suggested that PCB126 affect the GCs apoptosis, and mitochondrial apoptosis pathway was involved in this process.

Ovulation: Parallels With Inflammatory Processes

The midcycle surge of LH sets in motion interconnected networks of signaling cascades to bring about rupture of the follicle and release of the oocyte during ovulation. Many mediators of these LH-induced signaling cascades are associated with inflammation, leading to the postulate that ovulation is similar to an inflammatory response. First responders to the LH surge are granulosa and theca cells, which produce steroids, prostaglandins, chemokines, and cytokines, which are also mediators of inflammatory processes. These mediators, in turn, activate both nonimmune ovarian cells as well as resident immune cells within the ovary; additional immune cells are also attracted to the ovary. Collectively, these cells regulate proteolytic pathways to reorganize the follicular stroma, disrupt the granulosa cell basal lamina, and facilitate invasion of vascular endothelial cells. LH-induced mediators initiate cumulus expansion and cumulus oocyte complex detachment, whereas the follicular apex undergoes extensive extracellular matrix remodeling and a loss of the surface epithelium. The remainder of the follicle undergoes rapid angiogenesis and functional differentiation of granulosa and theca cells. Ultimately, these functional and structural changes culminate in follicular rupture and oocyte release. Throughout the ovulatory process, the importance of inflammatory responses is highlighted by the commonalities and similarities between many of these events associated with ovulation and inflammation. However, ovulation includes processes that are distinct from inflammation, such as regulation of steroid action, oocyte maturation, and the eventual release of the oocyte. This review focuses on the commonalities between inflammatory responses and the process of ovulation.

Cellular and molecular mechanisms of the preovulatory follicle differenciation and ovulation: What do we know in the mare relative to other species

Terminal follicular differentiation and ovulation are essential steps of reproduction. They are induced by the increase in circulating LH, and lead to the expulsion from the ovary of oocytes ready to be fertilized. This review summarizes our current understanding of cellular and molecular pathways that control ovulation using a broad mammalian literature, with a specific focus to the mare, which is unique in some aspects of ovarian function in some cases. Essential steps and key factors are approached. The first part of this review concerns LH, receptors and signaling, addressing the description of the equine gonadotropin and cloning, signaling pathways that are activated following the binding of LH to its receptors, and implication of transcription factors which better known are CCAAT-enhancer-binding proteins (CEBP) and cAMP response element-binding protein (CREB). The second and major part is devoted to the cellular and molecular actors within follicular cells during preovulatory maturation. We relate to 1) molecules involved in vascular permeability and vasoconstriction, 2) involvement of neuropeptides, such as kisspeptin, neurotrophins and neuronal growth factor, neuropeptide Y (NPY), 3) the modification of steroidogenesis, steroids intrafollicular levels and enzymes activity, 4) the local inflammation, with the increase in prostaglandins synthesis, and implication of leukotrienes, cytokines and glucocorticoids, 5) extracellular matrix remodelling with involvement of proteases, antiproteases and inhibitors, as well as relaxin, and finaly 6) the implication of oxytocine, osteopontin, growth factors and reactive oxygen species. The third part describes our current knowledge on molecular aspect of in vivo cumulus-oocyte-complexe maturation, with a specific focus on signaling pathways, paracrine factors, and intracellular regulations that occur in cumulus cells during expansion, and in the oocyte during nuclear and cytoplasmic meiosis resumption. Our aim was to give an overall and comprehensive map of the regulatory mechanisms that intervene within the preovulatory follicle during differentiation and ovulation.

C/EBPβ regulates Vegf gene expression in granulosa cells undergoing luteinization during ovulation in female rats

The ovulatory LH-surge increases Vegf gene expression in granulosa cells (GCs) undergoing luteinization during ovulation. To understand the factors involved in this increase, we examined the roles of two transcription factors and epigenetic mechanisms in rat GCs. GCs were obtained from rats treated with eCG before, 4 h, 8 h, 12 h and 24 h after hCG injection. Vegf mRNA levels gradually increased after hCG injection and reached a peak at 12 h. To investigate the mechanism by which Vegf is up-regulated after hCG injection, we focused on C/EBPβ and HIF1α. Their protein expression levels were increased at 12 h. The binding activity of C/EBPβ to the Vegf promoter region increased after hCG injection whereas that of HIF1α did not at this time point. The C/EBPβ binding site had transcriptional activities whereas the HIF1α binding sites did not have transcriptional activities under cAMP stimulation. The levels of H3K9me3 and H3K27me3, which are transcriptional repression markers, decreased in the C/EBPβ binding region after hCG injection. The chromatin structure of this region becomes looser after hCG injection. These results show that C/EBPβ regulates Vegf gene expression with changes in histone modifications and chromatin structure of the promoter region in GCs undergoing luteinization during ovulation.

Rosiglitazone increases expression of steroidogenic acute regulatory protein and progesterone production through PPARγ–EGFR–ERK1/2 in human cumulus granulosa cells

The mechanism by which rosiglitazone (ROSI: a thiazolidinedione (TZD)) affects steroid production in undifferentiated human granulosa cells is not known. In this study, cultured human cumulus granulosa cells were exposed to ROSI and pharmacological inhibitors of the extracellular signal-regulated kinase 1/2 (ERK1/2), epidermal growth factor receptor (EGFR) and peroxisome proliferator-activated receptor gamma (PPARγ) signalling pathways. Expression of progesterone biosynthetic enzymes, PPARγ and PPARα, progesterone production and ERK1/2 activation were analysed. After 48h, 30μM ROSI increased STAR, 3βHSD and PPARγ mRNA and elevated progesterone production in human cumulus granulosa cells. Addition of ERK1/2 (U0126), EGFR (AG1478) and PPARγ (GW9662) inhibitors prevented the ROSI-induced STAR mRNA expression and progesterone production after 48h. Inhibition of PPARγ, but not EGFR or ERK1/2, decreased the PPARγ mRNA levels induced by ROSI in human cumulus granulosa cells after 48h. On the other hand, U0126 and GW9662 prevented the ROSI-induced increase in PPARγ transcripts after 6h. Western blot analysis showed that ROSI induced a rapid ERK1/2 activation, which was prevented by inhibition of ERK1/2, EGFR and PPARγ in human cumulus granulosa cells. Overall, these data suggested that PPARγ, EGFR and ERK1/2 were involved in the stimulatory effect of ROSI on STAR expression and progesterone production in undifferentiated human cumulus granulosa cells.

FOS, a Critical Downstream Mediator of PGR and EGF Signaling Necessary for Ovulatory Prostaglandins in the Human Ovary

CONTEXT

Fos null mice failed to ovulate and form a corpus luteum (CL) even when given exogenous gonadotropins, suggesting that ovarian Fos expression is critical for successful ovulation and CL formation. However, little is known about FOS in the human ovary.

OBJECTIVES

To determine the expression, regulation, and function of FOS in human periovulatory follicles.

DESIGN/PARTICIPANTS

Timed periovulatory follicles were obtained from normally cycling women. Granulosa/lutein cells were collected from in vitro fertilization patients.

MAIN OUTCOME MEASURES

The in vivo expression after human chorionic gonadotropin (hCG) administration and in vitro regulation of FOS, JUN, JUNB, and JUND was evaluated at the mRNA and protein level. Binding of progesterone receptor (PGR) and FOS to their target genes was assessed by chromatin immunoprecipitation analyses. Prostaglandin E2 (PGE2) and progesterone were measured.

RESULTS

The expression of FOS, JUNB, and JUND drastically increased in ovulatory follicles after hCG administration. In human granulosa/lutein cell cultures, hCG increased the expression of FOS and JUN proteins. Inhibitors of PGR and epidermal growth factor (EGF) receptors reduced hCG-induced increases in the expression and phosphorylation of FOS. PGR bound to the FOS gene. A selective FOS inhibitor blocked hCG-induced increases in PGE2 and the expression of prostaglandin (PG) synthases and transporters (PTGES, SLCO2A1, and ABCC1). FOS bound to the promoter regions of these genes.

CONCLUSIONS

The increase of FOS/activator protein 1 in human periovulatory follicles after hCG administration is mediated by collaborative actions of PGR and EGF signaling and critical for the upregulated expression of key ovulatory genes required for the rise in ovulatory PG in human granulosa cells.

Erythropoietin-producing hepatocellular A7 triggering ovulation indicates a potential beneficial role for polycystic ovary syndrome

Background

The ovulatory dysfunction mechanisms underlying polycystic ovary syndrome (PCOS) are not completely understood. And the roles of EPHA7 and EPHA7-regulated pathway factors in the pathogenesis of anovulation remain to be elucidated.

Methods

We used human granulosa cells (hGCs) of PCOS and non-PCOS patients to measure EPHA7 and other target gene expressions. We performed in vitro experiments in KGN cells to verify the molecular mechanisms. Additionally, we conducted in vivo loss- and gain-of-function studies using EPHA7 shRNA lentivirus and recombinant EPHA7-Fc protein injection to identify the ovulation effects of EPHA7.

Findings

EPHA7 functions as a critically positive upstream factor for the expression of ERK1/2-mediated C/EBPβ. This protein, in turn, induced the expression of KLF4 and then ADAMTS1. Moreover, decreased abundance of EPHA7 was positively correlated with that of its downstream factors in hGCs of PCOS patients. Additionally, a 1-week functional EPHA7 shRNA lentivirus in rat ovaries contributed to decreased numbers of retrieved oocytes, and a 3-week functional lentivirus led to menstrual disorders and morphological polycystic changes in rat ovaries. More importantly, we found that EPHA7 triggered ovulation in rats, and it improved polycystic ovarian changes induced by DHEA in PCOS rats.

Interpretation

Our findings demonstrate a new role of EPHA7 in PCOS, suggesting that EPHA7 is an effective target for the development of innovative medicines to induce ovulation.

Fund

National Key Research and Development Program of China, National Natural Science Foundation, Shanghai Municipal Education Commission--Gaofeng Clinical Medicine, and Shanghai Commission of Science and Technology.

Coordination of Ovulation and Oocyte Maturation: A Good Egg at the Right Time

Ovulation is the appropriately timed release of a mature, developmentally competent oocyte from the ovary into the oviduct, where fertilization occurs. Importantly, ovulation is tightly linked with oocyte maturation, demonstrating the interdependency of these two parallel processes, both essential for female fertility. Initiated by pituitary gonadotropins, the ovulatory process is mediated by intrafollicular paracrine factors from the theca, mural, and cumulus granulosa cells, as well as the oocyte itself. The result is the induction of cumulus expansion, proteolysis, angiogenesis, inflammation, and smooth muscle contraction, which are each required for follicular rupture. These complex intercellular communication networks and the essential ovulatory genes have been well defined in mouse models and are highly conserved in primates, including humans. Importantly, recent discoveries in regulation of ovulation highlight new areas of investigation.

Regulation and function of runt-related transcription factors (RUNX1 and RUNX2) in goat granulosa cells

Transcription factors, runt-related transcription factor 1 (RUNX1) and 2 (RUNX2), belong to the runt-related (RUNX) gene family and play critical roles in mammalian reproduction processes. However, the regulatory mechanisms of RUNX1 and RUNX2 expression or their functions in goat follicles remain largely unknown. Herein, RUNX1 and RUNX2 proteins were detected in the oocytes and granulosa cells of preantral and antral follicles, as well as corpus luteum by immunohistochemistry. Treatments with human chorionic gonadotropin (hCG) or with the agonists and inhibitors of hCG-induced intracellular signaling pathways in granulosa cells in vitro, we found that hCG increased RUNX1 expression by activating PKC and PI3K signaling molecules, and increased RUNX2 expression by activating adenylate cyclase, PKC, and PI3K signaling molecules. We also demonstrated that miR-181b expression is dependent on the hCG-induced activation of PKC and PKA, and miR-222 expression is dependent on the hCG-induced activation of PI3K and PKC in cultured granulosa cells. Meanwhile, miR-181b and miR-222 suppressed RUNX1 and RUNX2 expression by targeting RUNX1 and RUNX2 3' untranslated regions (3'UTRs) with or without hCG, respectively. These results suggested that hCG-mediated miR-181b and miR-222 expression are important for the regulation of RUNX1 and RUNX2 expression levels in granulosa cells. To explore the specific functions of RUNX1 and RUNX2, we transfected RUNX1 and RUNX2 small interfering RNAs into primary cultured granulosa cells. Knockdown of RUNX1 and RUNX2 significantly decreased progesterone productions and the mRNA abundance of key steroidogenic enzymes (StAR, CYP11A1 and HSD3B) after hCG treatment. But only miR-222 increased estradiol secretion in goat granulosa cells. In addition, knockdown of RUNX1 and RUNX2 also promoted granulosa cell proliferation. The hormonally regulated expression of RUNX1 and RUNX2 in granulosa cells, their involvement in progesterone production, and promoted granulosa cell proliferation suggest important roles of RUNX1 and RUNX2 in follicular development and luteinization.

Reproductive, Physiological, and Molecular Outcomes in Female Mice Deficient in Dhh and Ihh

Ovarian development requires coordinate communications among oocytes, granulosa cells, and theca cells. Two Hedgehog (Hh) pathway ligands, Desert hedgehog (Dhh) and Indian hedgehog (Ihh), are produced by the granulosa cells and work together to regulate theca cell specification and development. Mice lacking both Dhh and Ihh had loss of normal ovarian function, which raised the question of which biological actions are specifically controlled by each ligand during folliculogenesis. By comparing the reproductive fitness, hormonal profiles, and ovarian transcriptomes among control, Dhh single-knockout (KO), Ihh KO, and Dhh/Ihh double-knockout (DKO) mice, we examined the specific roles of Dhh and Ihh in these processes. Dhh/Ihh DKO female mice were infertile because of a lack of theca cells and their steroid product androgen. Although Dhh and Ihh KO mice were fertile with normal folliculogenesis, they had decreased androgen production and alterations in their ovarian transcriptomes. Absence of Ihh led to aberrant steroidogenesis and elevated inflammation responses, which were not found in Dhh KO mouse ovaries, implicating that IHH has a greater impact than DHH on the activation of the Hh signaling pathway in the ovary. Our findings provide insight into not only how the Hh pathway influences folliculogenesis but also the distinct and overlapping roles of Dhh and Ihh in supporting ovarian development.

C/EBPβ Promotes STAT3 Expression and Affects Cell Apoptosis and Proliferation in Porcine Ovarian Granulosa Cells

Previous studies suggest that signal transducer and activator of transcription 3 (STAT3) and CCAAT/enhancer binding protein beta (C/EBPβ) play an essential role in ovarian granulosa cells (GCs) for mammalian follicular development. Several C/EBPβ putative binding sites were previously predicted on the STAT3 promoter in mammals. However, the molecular regulation of C/EBPβ on STAT3 and their effects on cell proliferation and apoptosis remain virtually unexplored in GCs. Using porcine GCs as a model, the 5′-deletion, luciferase report assay, mutation, chromatin immunoprecipitation, Annexin-V/PI staining and EdU assays were applied to investigate the molecular mechanism for C/EBPβ regulating the expression of STAT3 and their effects on the cell proliferation and apoptosis ability. We found that over and interfering with the expression of C/EBPβ significantly increased and decreased the messenger RNA (mRNA) and protein levels of STAT3, respectively. The dual luciferase reporter assay showed that C/EBPβ directly bound at −1397/−1387 of STAT3 to positively regulate the mRNA and protein expressions of STAT3. Both C/EBPβ and STAT3 were observed to inhibit cell apoptosis and promote cell proliferation. Furthermore, C/EBPβ might enhance the antiapoptotic and pro-proliferative effects of STAT3. These results would be of great insight in further exploring the molecular mechanism of C/EBPβ and STAT3 on the function of GCs and the development of ovarian follicles in mammals.

Endocrine, Paracrine, and Autocrine Signaling Pathways That Regulate Ovulation

The central role of luteinizing hormone (LH) and its receptor (LHCGR) in triggering ovulation has been recognized for decades. Because the LHCGR is present in the mural (outermost) granulosa cell layer of preovulatory follicles (POFs), the LH-initiated signal has to be transmitted to another somatic cell type (cumulus granulosa cells) and the oocyte to release a fertilizable oocyte. Recent studies have shown that activation of the LHCGR initiates vectorial transfer of information among the two somatic cell types and the oocyte and the molecules and signaling pathways involved are now better understood. This review summarizes the newer developments on the complex signaling pathways that regulate ovulation.