Aberrant uterine folding in mice disrupts implantation chamber formation and alignment of embryo-uterine axes.

The uterine luminal epithelium folds characteristically in mammals, including humans, horses and rodents. Improper uterine folding in horses results in pregnancy failure, but the precise function of folds remains unknown. Here, we uncover dynamic changes in the 3D uterine folding pattern during early pregnancy with the entire lumen forming pre-implantation transverse folds along the mesometrial-antimesometrial axis. Using a time course, we show that transverse folds are formed before embryo spacing, whereas implantation chambers form as the embryo begins attachment. Thus, folds and chambers are two distinct structures. Transverse folds resolve to form a flat implantation region, after which an embryo arrives at its center to attach and form the post-implantation chamber. Our data also suggest that the implantation chamber facilitates embryo rotation and its alignment along the uterine mesometrial-antimesometrial axis. Using WNT5A- and RBPJ-deficient mice that display aberrant folds, we show that embryos trapped in longitudinal folds display misalignment of the embryo-uterine axes, abnormal chamber formation and defective post-implantation morphogenesis. These mouse models with disrupted uterine folding provide an opportunity to understand uterine structure-based mechanisms that are crucial for implantation and pregnancy success. This article has an associated 'The people behind the papers' interview.

Aberrant activation of Notch1 signaling in the mouse uterine epithelium promotes hyper-proliferation by increasing estrogen sensitivity.

In mammals, the endometrium undergoes dynamic changes in response to estrogen and progesterone to prepare for blastocyst implantation. Two distinct types of endometrial epithelial cells, the luminal (LE) and glandular (GE) epithelial cells play different functional roles during this physiological process. Previously, we have reported that Notch signaling plays multiple roles in embryo implantation, decidualization, and postpartum repair. Here, using the uterine epithelial-specific Ltf-iCre, we showed that Notch1 signaling over-activation in the endometrial epithelium caused dysfunction of the epithelium during the estrous cycle, resulting in hyper-proliferation. During pregnancy, it further led to dysregulation of estrogen and progesterone signaling, resulting in infertility in these animals. Using 3D organoids, we showed that over-activation of Notch1 signaling increased the proliferative potential of both LE and GE cells and reduced the difference in transcription profiles between them, suggesting disrupted differentiation of the uterine epithelium. In addition, we demonstrated that both canonical and non-canonical Notch signaling contributed to the hyper-proliferation of GE cells, but only the non-canonical pathway was involved with estrogen sensitivity in the GE cells. These findings provided insights into the effects of Notch1 signaling on the proliferation, differentiation, and function of the uterine epithelium. This study demonstrated the important roles of Notch1 signaling in regulating hormone response and differentiation of endometrial epithelial cells and provides an opportunity for future studies in estrogen-dependent diseases, such as endometriosis.

The Known, the Unknown and the Future of the Pathophysiology of Endometriosis.

Endometriosis is one of the most common causes of chronic pelvic pain and infertility, affecting 10% of women of reproductive age. A delay of up to 9 years is estimated between the onset of symptoms and the diagnosis of endometriosis. Endometriosis is currently defined as the presence of endometrial epithelial and stromal cells at ectopic sites; however, advances in research on endometriosis have some authors believing that endometriosis should be re-defined as "a fibrotic condition in which endometrial stroma and epithelium can be identified". There are several theories on the etiology of the disease, but the origin of endometriosis remains unclear. This review addresses the role of microRNAs (miRNAs), which are naturally occurring post-transcriptional regulatory molecules, in endometriotic lesion development, the inflammatory environment within the peritoneal cavity, including the role that cytokines play during the development of the disease, and how animal models have helped in our understanding of the pathology of this enigmatic disease.

ARID1A-dependent maintenance of H3.3 is required for repressive CHD4-ZMYND8 chromatin interactions at super-enhancers.

BACKGROUND: SWI/SNF (BAF) chromatin remodeling complexes regulate lineage-specific enhancer activity by promoting accessibility for diverse DNA-binding factors and chromatin regulators. Additionally, they are known to modulate the function of the epigenome through regulation of histone post-translational modifications and nucleosome composition, although the way SWI/SNF complexes govern the epigenome remains poorly understood. Here, we investigate the function of ARID1A, a subunit of certain mammalian SWI/SNF chromatin remodeling complexes associated with malignancies and benign diseases originating from the uterine endometrium. RESULTS: Through genome-wide analysis of human endometriotic epithelial cells, we show that more than half of ARID1A binding sites are marked by the variant histone H3.3, including active regulatory elements such as super-enhancers. ARID1A knockdown leads to H3.3 depletion and gain of canonical H3.1/3.2 at ARID1A-bound active regulatory elements, and a concomitant redistribution of H3.3 toward genic elements. ARID1A interactions with the repressive chromatin remodeler CHD4 (NuRD) are associated with H3.3, and ARID1A is required for CHD4 recruitment to H3.3. ZMYND8 interacts with CHD4 to suppress a subset of ARID1A, CHD4, and ZMYND8 co-bound, H3.3+ H4K16ac+ super-enhancers near genes governing extracellular matrix, motility, adhesion, and epithelial-to-mesenchymal transition. Moreover, these gene expression alterations are observed in human endometriomas. CONCLUSIONS: These studies demonstrate that ARID1A-containing BAF complexes are required for maintenance of the histone variant H3.3 at active regulatory elements, such as super-enhancers, and this function is required for the physiologically relevant activities of alternative chromatin remodelers.

Notch effector recombination signal binding protein for immunoglobulin kappa J signaling is required for the initiation of endometrial stromal cell decidualization†.

The Notch signaling pathway is required for reproductive success. This pathway activates its transcriptional effector, recombination signal binding protein for immunoglobulin kappa J (Rbpj), to induce transcription of its target genes. This signaling pathway is required for successful decidualization, implantation, and uterine repair following parturition. To identify the compartmental specific roles of the Notch signaling pathway in the establishment of pregnancy, we generated epithelial and decidual stromal cell specific knockouts of Rbpj utilizing lactoferrin iCre and Prl8A2 iCre, respectively. Both conditional knockout mouse models were fertile. The Rbpj epithelial knockout mice displayed 27% resorption sites at E15.5, but this did not significantly impact the number of live born pups compared with controls. In addition, the Rbpj epithelial knockout mice displayed increased estrogen signaling in their stromal compartment. Given that both mouse models exhibited fertility comparable to control animals, the epithelial and stromal specific nature of the iCre recombinases utilized, and previously published Rbpj total uterine knockout mouse models, we conclude that Notch effector Rbpj signaling is required at the initiation of pregnancy to support decidualization in stromal cells, but that Rbpj is not required in the epithelial compartment nor is it required for post-implantation pregnancy success.

Early growth response 1 transcription factor is essential for the pathogenic properties of human endometriotic epithelial cells.

Although a non-malignant gynecological disorder, endometriosis displays some pathogenic features of malignancy, such as cell proliferation, migration, invasion and adaptation to hypoxia. Current treatments of endometriosis include pharmacotherapy and/or surgery, which are of limited efficacy and often associated with adverse side effects. Therefore, to develop more effective therapies to treat this disease, a broader understanding of the underlying molecular mechanisms that underpin endometriosis needs to be attained. Using immortalized human endometriotic epithelial and stromal cell lines, we demonstrate that the early growth response 1 (EGR1) transcription factor is essential for cell proliferation, migration and invasion, which represent some of the pathogenic properties of endometriotic cells. Genome-wide transcriptomics identified an EGR1-dependent transcriptome in human endometriotic epithelial cells that potentially encodes a diverse spectrum of proteins that are known to be involved in tissue pathologies. To underscore the utility of this transcriptomic data set, we demonstrate that carbonic anhydrase 9 (CA9), a homeostatic regulator of intracellular pH, is not only a molecular target of EGR1 but is also important for maintaining many of the cellular properties of human endometriotic epithelial cells that are also ascribed to EGR1. Considering therapeutic intervention strategies are actively being developed for EGR1 and CAIX in the treatment of other pathologies, we believe EGR1 and its transcriptome (which includes CA9) will offer not only a new conceptual framework to advance our understanding of endometriosis but will also furnish new molecular vulnerabilities to be leveraged as potential therapeutic options in the future treatment of endometriosis.

Endometrial epithelial ARID1A is critical for uterine gland function in early pregnancy establishment.

Though endometriosis and infertility are clearly associated, the pathophysiological mechanism remains unclear. Previous work has linked endometrial ARID1A loss to endometriosis-related endometrial non-receptivity. Here, we show in mice that ARID1A binds and regulates transcription of the Foxa2 gene required for endometrial gland function. Uterine-specific deletion of Arid1a compromises gland development and diminishes Foxa2 and Lif expression. Deletion of Arid1a with Ltf-iCre in the adult mouse endometrial epithelium preserves the gland development while still compromising the gland function. Mice lacking endometrial epithelial Arid1a are severely sub-fertile due to defects in implantation, decidualization, and endometrial receptivity from disruption of the LIF-STAT3-EGR1 pathway. FOXA2 is also reduced in the endometrium of women with endometriosis in correlation with diminished ARID1A, and both ARID1A and FOXA2 are reduced in nonhuman primates induced with endometriosis. Our findings describe a role for ARID1A in the endometrial epithelium supporting early pregnancy establishment through the maintenance of gland function.

Notch1 is crucial for decidualization and maintaining the first pregnancy in the mouse†.

The endometrium undergoes a pregnancy-delivery-repair cycle multiple times during the reproductive lifespan in females. Decidualization is one of the critical events for the success of this essential process. We have previously reported that Notch1 is essential for artificial decidualization in mice. However, in a natural pregnancy, the deletion of Notch1 (PgrCre/+Notch1f/f, or Notch1d/d) only affects female fertility in the first 30 days of a 6-month fertility test, but not the later stages. In the present study, we undertook a closer evaluation at the first pregnancy of these mice to attempt to understand this puzzling phenomenon. We observed a large number of pregnancy losses in Notch1d/d mice in their first pregnancy, which led to the subfertility observed in the first 30 days of the fertility test. We then demonstrated that the initial pregnancy loss is a consequence of impaired decidualization. Furthermore, we identified a group of genes that contribute to Notch1 regulated decidualization in a natural pregnancy. Gene ontogeny analysis showed that these differentially expressed genes in the natural pregnancy are involved in cell-cell and cell-matrix interactions, different from genes that have been previously identified from the artificial decidualization model, which contribute to cell proliferation and apoptosis. In summary, we determined that Notch1 is essential for normal decidualization in the mouse uterus only in the first pregnancy but not in subsequent ones.

Genetic and epigenetic changes in the eutopic endometrium of women with endometriosis: association with decreased endometrial αvß3 integrin expression.

About 40% of women with infertility and 70% of women with pelvic pain suffer from endometriosis. The pregnancy rate in women undergoing IVF with low endometrial integrin αvß3 (LEI) expression is significantly lower compared to the women with high endometrial integrin αvß3 (HEI). Mid-secretory eutopic endometrial biopsies were obtained from healthy controls (C; n=3), and women with HEI (n=4) and LEI (n=4) and endometriosis. Changes in gene expression were assessed using human gene arrays and DNA methylation data were derived using 385 K Two-Array Promoter Arrays. Transcriptional analysis revealed that LEI and C groups clustered separately with 396 differentially expressed genes (DEGs) (P<0.01: 275 up and 121 down) demonstrating that transcriptional and epigenetic changes are distinct in the LEI eutopic endometrium compared to the C and HEI group. In contrast, HEI vs C and HEI vs LEI comparisons only identified 83 and 45 DEGs, respectively. The methylation promoter array identified 1304 differentially methylated regions in the LEI vs C comparison. The overlap of gene and methylation array data identified 14 epigenetically dysregulated genes and quantitative RT-PCR analysis validated the transcriptomic findings. The analysis also revealed that aryl hydrocarbon receptor (AHR) was hypomethylated and significantly overexpressed in LEI samples compared to C. Further analysis validated that AHR transcript and protein expression are significantly (P<0.05) increased in LEI women compared to C. The increase in AHR, together with the altered methylation status of the 14 additional genes, may provide a diagnostic tool to identify the subset of women who have endometriosis-associated infertility.

Transcriptome Analyses of Myometrium from Fibroid Patients Reveals Phenotypic Differences Compared to Non-Diseased Myometrium.

Uterine fibroid tissues are often compared to their matched myometrium in an effort to understand their pathophysiology, but it is not clear whether the myometria of uterine fibroid patients represent truly non-disease control tissues. We analyzed the transcriptomes of myometrial samples from non-fibroid patients (M) and compared them with fibroid (F) and matched myometrial (MF) samples to determine whether there is a phenotypic difference between fibroid and non-fibroid myometria. Multidimensional scaling plots revealed that M samples clustered separately from both MF and F samples. A total of 1169 differentially expressed genes (DEGs) (false discovery rate < 0.05) were observed in the MF comparison with M. Overrepresented Gene Ontology terms showed a high concordance of upregulated gene sets in MF compared to M, particularly extracellular matrix and structure organization. Gene set enrichment analyses showed that the leading-edge genes from the TGFß signaling and inflammatory response gene sets were significantly enriched in MF. Overall comparison of the three tissues by three-dimensional principal component analyses showed that M, MF, and F samples clustered separately from each other and that a total of 732 DEGs from F vs. M were not found in the F vs. MF, which are likely understudied in the pathogenesis of uterine fibroids and could be key genes for future investigation. These results suggest that the transcriptome of fibroid-associated myometrium is different from that of non-diseased myometrium and that fibroid studies should consider using both matched myometrium and non-diseased myometrium as controls.

Physiologic Events of Embryo Implantation and Decidualization in Human and Non-Human Primates.

Reproduction is a fundamental process for the preservation of the human species. This process requires a sequence of orchestrated events that are necessary for a successful pregnancy. Two of the most critical steps in the establishment of human pregnancy are implantation and decidualization, which are required for maternal interactions with the developing embryo. This review primarily highlights the physiological aspects of these two events and the adverse pregnancy outcomes from defective implantation and decidualization. The focus of this review is to provide a general concept of the mechanisms involved during the window of implantation, description of components involved in the process and possible pathologies that could disrupt the embryo implantation and decidualization and specifically as it applies to women and non-human primates.

Autoimmune Regulator is required in female mice for optimal embryonic development and implantation†.

Autoimmune Regulator (AIRE) regulates central immune tolerance by inducing expression of tissue-restricted antigens in thymic medullary epithelial cells, thereby ensuring elimination of autoreactive T cells. Aire mutations in humans and targeted Aire deletion in mice result in multiorgan autoimmune disease, known in humans as autoimmune polyglandular syndrome type 1 (APS-1). APS-1 is characterized by the presence of adrenal insufficiency, chronic mucosal candidiasis, and/or hypoparathyroidism. Additionally, females often present with gonadal insufficiency and infertility. Aire-deficiency (KO) in mice results in oophoritis and age-dependent depletion of follicular reserves. Here, we found that while the majority of young 6-week-old Aire-KO females had normal follicular reserves, mating behavior, and ovulation rates, 50% of females experienced embryonic loss between gestation day (GD) 5.5 and 7.5 that could not be attributed to insufficient progesterone production or decidualization. The quality of GD0.5 embryos recovered from Aire KO mice was reduced, and when cultured in vitro, embryos displayed limited developmental capacity in comparison to those recovered from wild-type (WT) mice. Further, embryos flushed from Aire KO dams at GD3.5 were developmentally delayed in comparison to WT controls and had reduced trophoblastic outgrowth in vitro. We conclude that AIRE does not play a direct role in uterine decidualization. Rather, reduced fertility of Aire-deficient females is likely due to multiple factors, including oophoritis, delayed preimplantation development, and compromised implantation. These effects may be explained by autoimmune targeting of the ovary, embryo, or both. Alternatively, altered embryonic development could be due to a direct role for AIRE in early embryogenesis.

RBPJ mediates uterine repair in the mouse and is reduced in women with recurrent pregnancy loss.

Unexplained recurrent pregnancy loss (uRPL) is associated with repeated embryo loss and endometrial repair with elevated endometrial expression of inflammatory cytokines, including IFN-γ. Notch signaling through its transcription factor recombination signal binding protein Jκ (RBPJ) regulates mechanisms including the immune response and repair after tissue injury. Initially, null mutation of RBPJ in the mouse uterus ( Pgrcre/+Rbpjf/f; Rbpj c-KO) results in subfertility, but we have found that these mice become infertile after pregnancy as a result of dysfunctional postpartum uterine repair, including delayed endometrial epithelial and myometrial regeneration. RNA sequencing of postpartum uterine repair sites revealed global up-regulation of inflammatory pathways, including IFN signaling. Consistent with elevated IFN-γ, macrophages were recruited and polarized toward an M1-cytotoxic phenotype, which is associated with preventing repair and promoting further tissue injury. Through embryo transfer experiments, we show that dysfunctional postpartum repair directly impairs future embryo implantation in Rbpj c-KO mice. Last, we clinically correlated our findings from the Rbpj c-KO mouse in women diagnosed with uRPL. Reduced RBPJ in women with uRPL was associated with increased levels of IFN-γ. The data, taken together, indicate that RBPJ regulates inflammation during endometrial repair, which is essential for future pregnancy potential, and its dysregulation may serve as an unidentified contributor to uRPL in women.-Strug, M. R., Su, R.-W., Kim, T. H., Mauriello, A., Ticconi, C., Lessey, B. A., Young, S. L., Lim, J. M., Jeong, J.-W., Fazleabas, A. T. RBPJ mediates uterine repair in the mouse and is reduced in women with recurrent pregnancy loss.

Aberrant activation of canonical Notch1 signaling in the mouse uterus decreases progesterone receptor by hypermethylation and leads to infertility.

In mammalian reproduction, implantation is one of the most critical events. Failure of implantation and the subsequent decidualization contribute to more than 75% of pregnancy losses in women. Our laboratory has previously reported that inhibition of Notch signaling results in impaired decidualization in both women and a transgenic mouse model. In this study, we generated a Notch gain-of-function transgenic mouse by conditionally overexpressing the Notch1 intracellular domain (N1ICD) in the reproductive tract driven by a progesterone receptor (Pgr) -Cre. We show that the overexpression of N1ICD in the uterus results in complete infertility as a consequence of multiple developmental and physiological defects, including the absence of uterine glands and dysregulation of progesterone and estrogen signaling by a Recombination Signal Binding Protein Jκ-dependent signaling mechanism. We further show that the inhibition of progesterone signaling is caused by hypermethylation of its receptor Pgr by Notch1 overexpression through the transcription factor PU.1 and DNA methyltransferase 3b (Dnmt3b). We have generated a mouse model to study the consequence of increased Notch signaling in female reproduction and provide the first evidence, to our knowledge, that Notch signaling can regulate epigenetic modification of the Pgr.

Endometrial Immune Dysfunction in Recurrent Pregnancy Loss.

Recurrent pregnancy loss (RPL) represents an unresolved problem for contemporary gynecology and obstetrics. In fact, it is not only a relevant complication of pregnancy, but is also a significant reproductive disorder affecting around 5% of couples desiring a child. The current knowledge on RPL is largely incomplete, since nearly 50% of RPL cases are still classified as unexplained. Emerging evidence indicates that the endometrium is a key tissue involved in the correct immunologic dialogue between the mother and the conceptus, which is a condition essential for the proper establishment and maintenance of a successful pregnancy. The immunologic events occurring at the maternal-fetal interface within the endometrium in early pregnancy are extremely complex and involve a large array of immune cells and molecules with immunoregulatory properties. A growing body of experimental studies suggests that endometrial immune dysregulation could be responsible for several, if not many, cases of RPL of unknown origin. The present article reviews the major immunologic pathways, cells, and molecular determinants involved in the endometrial dysfunction observed with specific application to RPL.

Pharmacological blockage of the CXCR4-CXCL12 axis in endometriosis leads to contrasting effects in proliferation, migration, and invasion.

High levels of inflammatory factors including chemokines have been reported in peritoneal fluid and blood of women with endometriosis. CXCL12 mediates its action by interaction with its specific receptor, CXCR4, reported to be elevated in human endometriosis lesions and in the rat model of endometriosis. Activation of the CXCR4-CXCL12 axis increases cell proliferation, migration, and invasion of cancer cells. To obtain insights into the CXCR4 expression profile in lesions and endometrium, as well as functionality of the CXCR4-CXCL12 axis in endometriosis, we analyzed the expression of CXCR4 in tissues on a human tissue array and studied CXCL12-mediated activation of proliferation, invasion, and migration in vitro. We observed differences in levels of nuclear CXCR4 expression among lesion types, being higher in ovarian lesions. Endometriotic cell lines (12Z) showed higher levels of CXCR4, proliferative and migratory potential, and AKT phosphorylation/kinase activity compared to untreated control cells (endometrial epithelial cells). CXCL12 and endometriotic stromal cell-enriched media increased proliferation of non-endometriotic epithelial cells. CXCL12 caused a significant increase in 12Z cell invasion but had no effect on migration; AMD3100, a CXCR4-specific inhibitor, significantly increased invasion of 12Z cells but decreased their migration. However, treatment with CXCL12 plus AMD3100 significantly decreased invasion and migration of 12Z cells. In conclusion, the CXCR4-CXCL12 axis is functional in endometriosis cells, but the expression of CXCR4 varies among lesions. CXCL12 promoted proliferation, migration, and invasion of endometriotic cells, while inducing AKT phosphorylation and activity, but pharmacologically blocking this axis in the absence of the ligand induced their invasiveness.

The dynamic changes in the number of uterine natural killer cells are specific to the eutopic but not to the ectopic endometrium in women and in a baboon model of endometriosis.

BACKGROUND: Endometriosis is a common condition associated with growth of endometrial-like tissue beyond the uterine cavity. Previous reports have suggested a role for uNK cells in the pathogenesis of endometriosis postulating that survival and accumulation of menstrual endometrial tissue in the peritoneal cavity may relate to a reduction in the cytotoxic activity of peripheral blood NK cells. We aimed to assess the differences in percentage of uNK cells and their phenotypical characterization in eutopic and ectopic endometrial samples from women with and without endometriosis and baboons with induced endometriosis. METHODS: Eutopic and ectopic endometrial samples from 82 women across the menstrual cycle with/without endometriosis and from 8 baboons before and after induction of endometriosis were examined for CD56 and NKp30 expression with immunohistochemistry, quantified using computer assisted image analysis. Curated secretory phase endometrial microarray datasets were interrogated for NK cell receptors and their ligands. In silico data was validated by examining the secretory phase eutopic endometrium of women with and without endometriosis (n = 8/group) for the immuno-expression of BAG6 protein. RESULTS: The percentage of uNK cells increased progressively from the proliferative phase with the highest levels in the late secretory phase in the eutopic endometrium of women with and without endometriosis. The percentage of uNK cells in ectopic lesions remained significantly low throughout the cycle. In baboons, induction of endometriosis increased the percentage of uNK in the ectopic lesions but not NKp30. Published eutopic endometrial microarray datasets demonstrated significant upregulation of NKp30 and its ligand BAG6 in women with endometriosis compared with controls. Immunohistochemical staining scores for BAG6 was also significantly higher in secretory phase eutopic endometrium from women with endometriosis compared with the endometrium of healthy women (n = 8/group). CONCLUSIONS: The dynamic increase in the percentage of uNK cells in the secretory phase is preserved in the endometrium of women with endometriosis. The low number of uNK cells in human and baboon ectopic lesions may be due to their exaggerated reduction in hormonal responsiveness (progesterone resistance).

ARID1A Is Essential for Endometrial Function during Early Pregnancy.

AT-rich interactive domain 1A gene (ARID1A) loss is a frequent event in endometriosis-associated ovarian carcinomas. Endometriosis is a disease in which tissue that normally grows inside the uterus grows outside the uterus, and 50% of women with endometriosis are infertile. ARID1A protein levels were significantly lower in the eutopic endometrium of women with endometriosis compared to women without endometriosis. However, an understanding of the physiological effects of ARID1A loss remains quite poor, and the function of Arid1a in the female reproductive tract has remained elusive. In order to understand the role of Arid1a in the uterus, we have generated mice with conditional ablation of Arid1a in the PGR positive cells (Pgrcre/+Arid1af/f; Arid1ad/d). Ovarian function and uterine development of Arid1ad/d mice were normal. However, Arid1ad/d mice were sterile due to defective embryo implantation and decidualization. The epithelial proliferation was significantly increased in Arid1ad/d mice compared to control mice. Enhanced epithelial estrogen activity and reduced epithelial PGR expression, which impedes maturation of the receptive uterus, was observed in Arid1ad/d mice at the peri-implantation period. The microarray analysis revealed that ARID1A represses the genes related to cell cycle and DNA replication. We showed that ARID1A positively regulates Klf15 expression with PGR to inhibit epithelial proliferation at peri-implantation. Our results suggest that Arid1a has a critical role in modulating epithelial proliferation which is a critical requisite for fertility. This finding provides a new signaling pathway for steroid hormone regulation in female reproductive biology and furthers our understanding of the molecular mechanisms that underlie dysregulation of hormonal signaling in human reproductive disorders such as endometriosis.