Stimulation of aromatase P450 promoter (II) activity in endometriosis and its inhibition in endometrium are regulated by competitive binding of steroidogenic factor-1 and chicken ovalbumin upstream promoter transcription factor to the same cis-acting element

The use of hormonal contraceptives in fertility treatments: a committee opinion

The use of hormonal contraception can be considered to aid in the timing of assisted reproductive technology cycles, reduce the risk of ovarian cysts at in vitro fertilization cycle initiation, and optimize visualization before hysteroscopy.

Network pharmacology and experimental validation to explore the potential mechanism of Sanjie Zhentong Capsule in endometriosis treatment

PURPOSE

Sanjie Zhentong Capsule (SZC) is gradually becoming widely used in the treatment of endometriosis (EMs) and has demonstrated an excellent curative effect in the clinic. However, the active components and mechanisms of Sanjie Zhentong Capsule (SZC) in the treatment of endometriosis (EMs) remain unclear, and further research is needed to explore the effects of Sanjie Zhentong Capsule (SZC).

MATERIALS AND METHODS

First, a drug target database of Sanjie Zhentong capsule (SZC) was established by consulting the TCMSP database and related literature. An endometriosis (EMs) disease target database was then established by consulting the GeneCards, OMIM and Drug Bank databases. The overlapping genes of SZC and EMs were determined, and protein-protein interactions (PPIs), gene ontology (GO) and Kyoto Gene and Genome Encyclopedia (KEGG) analyses were performed to predict the potential therapeutic mechanisms. Molecular docking was used to observe whether the key active ingredients and targets predicted by network pharmacology had good binding energy. Finally, in vitro experiments such as CCK-8, flow cytometry and RT-PCR assays were carried out to preliminarily verify the potential mechanisms.

RESULTS

Through the construction of a pharmacological network, we identified a total of 28 active components in SZC and 52 potential therapeutic targets. According to GO and KEGG enrichment analyses, the effects of SZC treatment may be related to oxidative stress, steroid metabolism, apoptosis and proliferation. We also experimentally confirmed that SZC can regulate the expression of steroid hormone biosynthesis-related genes, inhibit ectopic endometrial stromal cell (EESC) proliferation and oxidative stress, and promote apoptosis.

CONCLUSION

This study explored the potential mechanism of SZC in the treatment of EMs through network pharmacology and experiments, providing a basis for further future research on SZC in the treatment of EMs.

Novel therapeutic targets to improve IVF outcomes in endometriosis patients: a review and future prospects

BACKGROUND

Patients with endometriosis often experience infertility and have poor IVF outcomes, with low fertilization and pregnancy rates. Although many theories have tried to explain the mechanisms underlying infertility in these patients, none of them is conclusive.

OBJECTIVE AND RATIONALE

In this review, we discuss the pathologic mechanisms through which endometriosis likely leads to infertility along with the therapeutic options used to date to treat endometriosis-related infertility and, thereby, to improve IVF outcomes in patients with endometriosis.

SEARCH METHODS

We performed a comprehensive literature search of clinical outcomes in endometriosis and the molecular mechanisms contributing to oocyte quality using the PubMed database to identify human and animal studies published from 1992 until September 2020. In total, 123 manuscripts were included.

OUTCOMES

While some theories propose that endometriosis patients may have fertility problems as a result of decreased endometrial receptivity, others reinforce the idea that infertility could be associated with oocyte alterations and lower implantation rates. Single-cell RNA sequencing of oocytes from patients with endometriosis has identified dysregulated mechanisms involved in steroid metabolism and biosynthesis, response to oxidative stress and cell cycle regulation. Dysregulation of these mechanisms could result in the poor IVF outcomes observed in patients with endometriosis. Further, impaired steroidogenesis may directly affect oocyte and embryo quality. Increased oxidative stress in patients with endometriosis also has a detrimental effect on the follicular microenvironment, inducing cell cycle dysregulation in oocytes, poor oocyte quality, and infertility. Moreover, granulosa cells in the context of endometriosis undergo increased apoptosis and have an altered cell cycle that could adversely affect folliculogenesis, oocyte and embryo quality, and IVF outcomes. Endometriosis is also associated with inflammatory damage and impaired angiogenesis, which could be directly correlated with poor IVF outcomes. While therapeutic options using GnRH analogues, progestins and aromatase inhibitors do not improve endometriosis-related infertility, anti-inflammatory agents and antioxidant supplementation could improve oocyte quality as well as implantation and clinical pregnancy rates in patients with endometriosis.

WIDER IMPLICATIONS

Endometriosis is a heterogeneous disease whose pathogenesis is complex and could affect fertility by altering a collection of molecular mechanisms in oocytes. Thus, a single model is not sufficient to describe endometriosis-related infertility. Dysregulation of steroidogenesis, oxidative stress, cell cycle progression, inflammation and angiogenesis in the follicular environment and oocytes in individuals with endometriosis are all possible contributors to endometriosis-related infertility. Therefore, treatments targeting these mechanisms could be therapeutic alternatives to improve IVF outcomes for these patients.

Illuminating the "Black Box" of Progesterone-Dependent Embryo Implantation Using Engineered Mice

Synchrony between progesterone-driven endometrial receptivity and the arrival of a euploid blastocyst is essential for embryo implantation, a prerequisite event in the establishment of a successful pregnancy. Advancement of embryo implantation within the uterus also requires stromal fibroblasts of the endometrium to transform into epithelioid decidual cells, a progesterone-dependent cellular transformation process termed decidualization. Although progesterone is indispensable for these cellular processes, the molecular underpinnings are not fully understood. Because human studies are restricted, much of our fundamental understanding of progesterone signaling in endometrial periimplantation biology comes from in vitro and in vivo experimental systems. In this review, we focus on the tremendous progress attained with the use of engineered mouse models together with high throughput genome-scale analysis in disclosing key signals, pathways and networks that are required for normal endometrial responses to progesterone during the periimplantation period. Many molecular mediators and modifiers of the progesterone response are implicated in cross talk signaling between epithelial and stromal cells of the endometrium, an intercellular communication system that is critical for the ordered spatiotemporal control of embryo invasion within the maternal compartment. Accordingly, derailment of these signaling systems is causally linked with infertility, early embryo miscarriage and gestational complications that symptomatically manifest later in pregnancy. Such aberrant progesterone molecular responses also contribute to endometrial pathologies such as endometriosis, endometrial hyperplasia and cancer. Therefore, our review makes the case that further identification and functional analysis of key molecular mediators and modifiers of the endometrial response to progesterone will not only provide much-needed molecular insight into the early endometrial cellular changes that promote pregnancy establishment but lend credible hope for the development of more effective mechanism-based molecular diagnostics and precision therapies in the clinical management of female infertility, subfertility and a subset of gynecological morbidities.

Three-Dimensional Biofabrication Models of Endometriosis and the Endometriotic Microenvironment

Endometriosis occurs when endometrial-like tissue grows outside the uterine cavity, leading to pelvic pain, infertility, and increased risk of ovarian cancer. The present study describes the optimization and characterization of cellular spheroids as building blocks for Kenzan scaffold-free method biofabrication and proof-of-concept models of endometriosis and the endometriotic microenvironment. The spheroid building blocks must be of a specific diameter (~500 μm), compact, round, and smooth to withstand Kenzan biofabrication. Under optimized spheroid conditions for biofabrication, the endometriotic epithelial-like cell line, 12Z, expressed high levels of estrogen-related genes and secreted high amounts of endometriotic inflammatory factors that were independent of TNFα stimulation. Heterotypic spheroids, composed of 12Z and T-HESC, an immortalized endometrial stromal cell line, self-assembled into a biologically relevant pattern, consisting of epithelial cells on the outside of the spheroids and stromal cells in the core. 12Z spheroids were biofabricated into large three-dimensional constructs alone, with HEYA8 spheroids, or as heterotypic spheroids with T-HESC. These three-dimensional biofabricated constructs containing multiple monotypic or heterotypic spheroids represent the first scaffold-free biofabricated in vitro models of endometriosis and the endometriotic microenvironment. These efficient and innovative models will allow us to study the complex interactions of multiple cell types within a biologically relevant microenvironment.

Extracellular vesicle-associated VEGF-C promotes lymphangiogenesis and immune cells infiltration in endometriosis

Endometriosis is a highly prevalent gynecological disease with severe negative impacts on life quality and financial burden. Unfortunately, there is no cure for this disease, which highlights the need for further investigation about the pathophysiology of this disease to provide clues for developing novel therapeutic regimens. Herein, we identified that vascular endothelial growth factor (VEGF)-C, a potent lymphangiogenic factor, is up-regulated in endometriotic cells and contributes to increased lymphangiogenesis. Bioinformatic analysis and molecular biological characterization revealed that VEGF-C is negatively regulated by an orphan nuclear receptor, chicken ovalbumin upstream promoter-transcription factor II (COUP-TFII). Further studies demonstrated that proinflammatory cytokines, via suppression of COUP-TFII level, induce VEGF-C overexpression. More importantly, we show that functional VEGF-C is transported by extracellular vesicles (EVs) to enhance the lymphangiogenic ability of lymphatic endothelial cells. Autotransplanted mouse model of endometriosis showed lenvatinib treatment abrogated the increased lymphatic vessels development in the endometriotic lesion, enlarged retroperitoneal lymph nodes, and immune cells infiltration, indicating that blocking VEGF-C signaling can reduce local chronic inflammation and concomitantly endometriosis development. Evaluation of EV-transmitted VEGF-C from patients' sera demonstrates it is a reliable noninvasive way for clinical diagnosis. Taken together, we identify the vicious cycle of inflammation, COUP-TFII, VEGF-C, and lymphangiogenesis in the endometriotic microenvironment, which opens up new horizons in understanding the pathophysiology of endometriosis. VEGF-C not only can serve as a diagnostic biomarker but also a molecular target for developing therapeutic regimens.

Steroid hormones regulate genome-wide epigenetic programming and gene transcription in human endometrial cells with marked aberrancies in endometriosis

Programmed cellular responses to cycling ovarian-derived steroid hormones are central to normal endometrial function. Abnormalities therein, as in the estrogen-dependent, progesterone-"resistant" disorder, endometriosis, predispose to infertility and poor pregnancy outcomes. The endometrial stromal fibroblast (eSF) is a master regulator of pregnancy success. However, the complex hormone-epigenome-transcriptome interplay in eSF by each individual steroid hormone, estradiol (E2) and/or progesterone (P4), under physiologic and pathophysiologic conditions, is poorly understood and was investigated herein. Genome-wide analysis in normal, early and late stage eutopic eSF revealed: i) In contrast to P4, E2 extensively affected the eSF DNA methylome and transcriptome. Importantly, E2 resulted in a more open versus closed chromatin, confirmed by histone modification analysis. Combined E2 with P4 affected a totally different landscape than E2 or P4 alone. ii) P4 responses were aberrant in early and late stage endometriosis, and mapping differentially methylated CpG sites with progesterone receptor targets from the literature revealed different but not decreased P4-targets, leading to question the P4-"resistant" phenotype in endometriosis. Interestingly, an aberrant E2-response was noted in eSF from endometriosis women; iii) Steroid hormones affected specific genomic contexts and locations, significantly enriching enhancers and intergenic regions and minimally involving proximal promoters and CpG islands, regardless of hormone type and eSF disease state. iv) In eSF from women with endometriosis, aberrant hormone-induced methylation signatures were mainly due to existing DNA methylation marks prior to hormone treatments and involved known endometriosis genes and pathways. v) Distinct DNA methylation and transcriptomic signatures revealed early and late stage endometriosis comprise unique disease subtypes. Taken together, the data herein, for the first time, provide significant insight into the hormone-epigenome-transcriptome interplay of each steroid hormone in normal eSF, and aberrant E2 response, distinct disease subtypes, and pre-existing epigenetic aberrancies in the setting of endometriosis, provide mechanistic insights into how endometriosis affects endometrial function/dysfunction.

Endometriosis and nuclear receptors

BACKGROUND

Endometriosis is recognized as a steroid-dependent disorder; however, the precise roles of nuclear receptors (NRs) in steroid responsiveness and other signaling pathways are not well understood.

OBJECTIVE AND RATIONALE

Over the past several years, a number of paradigm-shifting breakthroughs have occurred in the area of NRs in endometriosis. We review and clarify new information regarding the mechanisms responsible for: (i) excessive estrogen biosynthesis, (ii) estrogen-dependent inflammation, (iii) defective differentiation due to progesterone resistance and (iv) enhanced survival due to deficient retinoid production and action in endometriosis. We emphasize the roles of the relevant NRs critical for these pathological processes in endometriosis.

SEARCH METHODS

We conducted a comprehensive search using PubMed for human, animal and cellular studies published until 2018 in the following areas: endometriosis; the steroid and orphan NRs, estrogen receptors alpha (ESR1) and beta (ESR2), progesterone receptor (PGR), steroidogenic factor-1 (NR5A1) and chicken ovalbumin upstream promoter-transcription factor II (NR2F2); and retinoids.

OUTCOMES

Four distinct abnormalities in the intracavitary endometrium and extra-uterine endometriotic tissue underlie endometriosis progression: dysregulated differentiation of endometrial mesenchymal cells, abnormal epigenetic marks, inflammation activated by excess estrogen and the development of progesterone resistance. Endometriotic stromal cells compose the bulk of the lesions and demonstrate widespread epigenetic abnormalities. Endometriotic stromal cells also display a wide range of abnormal NR expression. The orphan NRs NR5A1 and NR2F2 compete to regulate steroid-synthesizing genes in endometriotic stromal cells; NR5A1 dominance gives rise to excessive estrogen formation. Endometriotic stromal cells show an abnormally low ESR1:ESR2 ratio due to excessive levels of ESR2, which mediates an estrogen-driven inflammatory process and prostaglandin formation. These cells are also deficient in PGR, leading to progesterone resistance and defective retinoid synthesis. The pattern of NR expression, involving low ESR1 and PGR and high ESR2, is reminiscent of uterine leiomyoma stem cells. This led us to speculate that endometriotic stromal cells may display stem cell characteristics found in other uterine tissues. The biologic consequences of these abnormalities in endometriotic tissue include intense inflammation, defective differentiation and enhanced survival.

WIDER IMPLICATIONS

Steroid- and other NR-related abnormalities exert genome-wide biologic effects via interaction with defective epigenetic programming and enhance inflammation in endometriotic stromal cells. New synthetic ligands, targeting PGR, retinoic acid receptors and ESR2, may offer novel treatment options.

Dog Steroidogenic Factor-1: Molecular cloning and analysis of epigenetic regulation

Steroidogenic factor 1 (SF-1) is a nuclear receptor that is important in steroid hormone production, and adrenal and gonad development. The SF-1 gene is highly conserved among most vertebrates. However, dog SF-1 registered in public databases, such as CanFam3.1, lacks the 5' end compared to other mammals including mouse, human, bovine, and cat. Whether this defect is due to species differences or database error is unclear. Here, we determined the full-length dog SF-1 cDNA sequence and identified the missing 5' end sequence in the databases. The coding region of the dog SF-1 gene has 1,386 base pairs, and the protein has 461 amino acid residues. Sequence alignment analysis among vertebrates revealed that the 5' end sequence of dog SF-1 cDNA is highly conserved compared to other vertebrates. The genomic position of the first exon was determined, and its promoter region sequence was analyzed. The DNA methylation state at the basal promoter and the expression of dog SF-1 in steroidogenic tissues and non-steroidogenic cells were examined. CpG sites at the basal promoter displayed methylation kinetics inversely correlated with gene expression. The promoter was hypomethylated and hypermethylated in SF-1 expressing and non-SF-1 expressing tissues, respectively. In conclusion, we identified the true full sequence of dog SF-1 cDNA and determined the genome sequence around the first exon. The gene is under the control of epigenetic regulation, such as DNA methylation, at the promoter.

Endometriosis: The Role of Iron Overload and Ferroptosis

Iron is an essential element for cell survival, and iron deficiency is a known risk factor for many reproductive disorders. Paradoxically, such disorders are also seen more commonly under conditions of iron excess. Here, we focus on the problem of iron overload in women's health, using endometriosis as a model system. We propose (i) that a primary defect in endometriosis is abnormal eutopic endometrium characterized by resistance to ferroptosis, a process of iron-mediated non-apoptotic programmed cell death, which allows cells spread via retrograde menstruation to survive, implant, and establish endometriotic lesions within the abdominal cavity, and (ii) that dysregulated iron homeostasis may be critical to the subsequent pathophysiology of endometriotic lesions with localized iron overload and inflammation. We further investigate the association between endometriosis and hypercholesterolemia and suggest that an interaction between the mevalonate cholesterol biosynthetic pathway and ferroptosis signaling may provide a molecular basis to explain how it is that, in some women, endometrial tissues survive and thrive under ferroptotic pressure, colonize at ectopic sites, and expand into endometriotic lesions.

Platelets induce increased estrogen production through NF-κB and TGF-β1 signaling pathways in endometriotic stromal cells

Endometriosis is estrogen-dependent disorder. Two theories provide the explanations for the increased estrogen production. One is the feed-forward loop model linking inflammation and estrogen production. The more recent model evokes the tissue hypoxia resulting from endometrial debris detached and then regurgitated to the peritoneal cavity. Both models tacitly assume that everything occurs within the endometriotic stromal cells, seemingly without the need for exogenous factors. This study was undertaken to investigate as whether platelets may be responsible for local estrogen overproduction. We employed in vitro experimentation that evaluated the 17β-estradiol (E₂) levels in endometriotic stromal cells treated with activated platelets, and the genes and protein expression levels of StAR, HSD3B2, aromatase, and HSD17B1, as well as their upstream genes/proteins such as NF-κB, TGF-β1, HIF-1α, SF-1 and phosphorylated CREB. In addition, we conducted 2 animal experimentations using platelet depletion/infusion and also neutralization of NF-κB and TGF-β1, followed by immunohistochemistry analysis of involved in StAR, HSD3B2, aromatase, and HSD17B1, as well as SF-1 and p-CREB. We found that treatment of endometriotic stromal cells by activated platelets increase the E₂ production by 4.5 fold, and concomitant with increased gene and protein expression of StAR, HSD3B2, aromatase, and HSD17B1, the four genes/enzymes important to estrogen synthesis, along with their upstream genes HIF-1α, SF-1 and phosphorylated CREB. Moreover, platelets activate these genes through the activation of NF-κB and/or TGF-β1, and antagonism of either signaling pathway can abolish the induction of the 4 genes and thus increased estrogen production. The two animal experimentations confirmed these changes. Thus, platelets increase the E₂ production in endometriotic stromal cells through upregulation of StAR, HSD3B2, aromatase, and HSD17B1 via the activation of NF-κB and/or TGF-β1. These findings provide a yet another compelling piece of evidence that endometriotic lesions are indeed wounds undergoing repeated tissue injury and repair. They strongly indicate that non-hormonal therapeutics for endometriosis is theoretically viable, with anti-platelet therapy being one promising avenue.

Endometriosis-Associated Macrophages: Origin, Phenotype, and Function

Endometriosis is a complex, heterogeneous, chronic inflammatory condition impacting ~176 million women worldwide. It is associated with chronic pelvic pain, infertility, and fatigue, and has a substantial impact on health-related quality of life. Endometriosis is defined by the growth of endometrial-like tissue outside the uterus, typically on the lining of the pelvic cavity and ovaries (known as "lesions"). Macrophages are complex cells at the center of this enigmatic condition; they are critical for the growth, development, vascularization, and innervation of lesions as well as generation of pain symptoms. In health, tissue-resident macrophages are seeded during early embryonic life are vital for development and homeostasis of tissues. In the adult, under inflammatory challenge, monocytes are recruited from the blood and differentiate into macrophages in tissues where they fulfill functions, such as fighting infection and repairing wounds. The interplay between tissue-resident and recruited macrophages is now at the forefront of macrophage research due to their differential roles in inflammatory disorders. In some cancers, tumor-associated macrophages (TAMs) are comprised of tissue-resident macrophages and recruited inflammatory monocytes that differentiate into macrophages within the tumor. These macrophages of different origins play differential roles in disease progression. Herein, we review the complexities of macrophage dynamics in health and disease and explore the paradigm that under disease-modified conditions, macrophages that normally maintain homeostasis become modified such that they promote disease. We also interrogate the evidence to support the existence of multiple phenotypic populations and origins of macrophages in endometriosis and how this could be exploited for therapy.

COUP-TFII in Health and Disease

The nuclear receptors (NRs) belong to a vast family of evolutionary conserved proteins acting as ligand-activated transcription factors. Functionally, NRs are essential in embryogenesis and organogenesis and in adulthood they are involved in almost every physiological and pathological process. Our knowledge of NRs action has greatly improved in recent years, demonstrating that both their expression and activity are tightly regulated by a network of signaling pathways, miRNA and reciprocal interactions. The Chicken Ovalbumin Upstream Promoter Transcription Factor II (COUP-TFII, NR2F2) is a NR classified as an orphan due to the lack of a known natural ligand. Although its expression peaks during development, and then decreases considerably, in adult tissues, COUP-TFII is an important regulator of differentiation and it is variably implicated in tissues homeostasis. As such, alterations of its expression or its transcriptional activity have been studied and linked to a spectrum of diseases in organs and tissues of different origins. Indeed, an altered COUP-TFII expression and activity may cause infertility, abnormality in the vascular system and metabolic diseases like diabetes. Moreover, COUP-TFII is actively investigated in cancer research but its role in tumor progression is yet to be fully understood. In this review, we summarize the current understanding of COUP-TFII in healthy and pathological conditions, proposing an updated and critical view of the many functions of this NR.

Local estrogen formation and its regulation in endometriosis

BACKGROUND

It has been well established that endometriosis is an estrogen-dependent disease. Although the exact pathogenesis of the disease is still unclear, it is known to be characterized by estrogen-dependent growth and maintenance of the ectopic endometrium and increased local estrogen production.

METHODS

The authors reviewed studies on local estrogen production and estrogen activities mediated by estrogen receptors in endometriotic tissues.

MAIN FINDINGS

Aberrant expression of several enzymes in local endometriotic lesions contributed to the production and metabolism of estrogens. Aromatase was one of the key therapeutic targets for the regulation of local estrogen formation. Our findings suggest that PGC-1a, a transcriptional coactivator-modulating steroid hormone, regulates aromatase expression and activity. Estrogen activities mediated by different types of estrogen receptors abnormally elevated in local tissues could also be involved in the development of endometriosis. The authors demonstrated that the isoflavone aglycone, a partial agonist of the estrogen receptor, suppressed the formation of endometriotic lesions.

CONCLUSIONS

Local estrogen production and estrogen activity mediated by estrogen receptors are important potential therapeutic targets for endometriosis.

Endometriosis

Pelvic endometriosis is a complex syndrome characterized by an estrogen-dependent chronic inflammatory process that affects primarily pelvic tissues, including the ovaries. It is caused when shed endometrial tissue travels retrograde into the lower abdominal cavity. Endometriosis is the most common cause of chronic pelvic pain in women and is associated with infertility. The underlying pathologic mechanisms in the intracavitary endometrium and extrauterine endometriotic tissue involve defectively programmed endometrial mesenchymal progenitor/stem cells. Although endometriotic stromal cells, which compose the bulk of endometriotic lesions, do not carry somatic mutations, they demonstrate specific epigenetic abnormalities that alter expression of key transcription factors. For example, GATA-binding factor-6 overexpression transforms an endometrial stromal cell to an endometriotic phenotype, and steroidogenic factor-1 overexpression causes excessive production of estrogen, which drives inflammation via pathologically high levels of estrogen receptor-β. Progesterone receptor deficiency causes progesterone resistance. Populations of endometrial and endometriotic epithelial cells also harbor multiple cancer driver mutations, such as KRAS, which may be associated with the establishment of pelvic endometriosis or ovarian cancer. It is not known how interactions between epigenomically defective stromal cells and the mutated genes in epithelial cells contribute to the pathogenesis of endometriosis. Endometriosis-associated pelvic pain is managed by suppression of ovulatory menses and estrogen production, cyclooxygenase inhibitors, and surgical removal of pelvic lesions, and in vitro fertilization is frequently used to overcome infertility. Although novel targeted treatments are becoming available, as endometriosis pathophysiology is better understood, preventive approaches such as long-term ovulation suppression may play a critical role in the future.

Increased circulating miR-370-3p regulates steroidogenic factor 1 in endometriosis

Endometriosis is a gynecologic disease common among reproductive-aged women caused by the growth of endometrial tissue outside the uterus. Altered expression of numerous genes and microRNAs has been reported in endometriosis. Steroidogenic factor 1 (SF-1), an essential transcriptional regulator of multiple genes involved in estrogen biosynthesis, is aberrantly increased and plays an important role in the pathogenesis of endometriosis. Here, we show the expression of SF-1 in endometriosis is regulated by miR-370-3p. Sera and tissue were collected from 20 women surgically diagnosed with endometriosis and 26 women without endometriosis. We found that miR-370-3p levels were decreased in the serum of patients with endometriosis while SF-1 mRNA levels were inversely upregulated in endometriotic lesions compared with respective controls. Transfection of primary endometriotic cells with miR-370-3p mimic or inhibitor resulted in the altered expression of SF-1 and SF-1 downstream target genes steroidogenic acute regulatory protein (StAR) and CYP19A1. Overexpression of miR-370-3p inhibited cell proliferation and induced apoptosis in endometriotic cells. This study reveals that miR-370-3p functions as a negative regulator of SF-1 and cell proliferation in endometriotic cells. We suggest a novel therapeutic strategy for controlling SF-1 in endometriosis.

Hypoxia: The force of endometriosis

AIM

Summarize recent findings of how hypoxia regulates numerous important processes to facilitate the implantation, proliferation and progression of ectopic endometriotic lesions.

METHODS

Most up-to-date evidences about how hypoxia contributes to the disease pathogenesis of endometriosis and potential therapeutic approaches were collected by conducting a comprehensive search of medical literature electronic databases. Quality of data was analyzed by experienced experts including gynecologist and basic scientists.

RESULTS

Uterus is a highly vascularized organ, which makes endometrial cells constantly expose to high concentration of oxygen. When endometrial tissues shed off from the eutopic uterus and retrograde to the peritoneal cavity, they face severe hypoxic stress. Even with successful implantation to ovaries or peritoneum, the hypoxic stress remains as a critical issue because endometrial cells are used to live in the well-oxygenated environment. Under the hypoxia condition, cells undergo epigenetic modulation and evolve several survival processes including steroidogenesis, angiogenesis, inflammation and metabolic switch. The complex gene regulatory network driven by hypoxia ensures endometriotic cells can survive under the hostile peritoneal microenvironment.

CONCLUSION

Hypoxia plays critical roles in promoting pathological processes to facilitate the development of endometriosis. Targeting hypoxia-mediated gene network represents an alternative approach for the treatment of endometriosis.

Farnesoid X Receptor Agonist GW4064 Inhibits Aromatase and ERβ Expression in Human Endometriotic Stromal Cells

Endometriosis is an estrogen-dependent disease. Farnesoid X receptor (FXR) activation has been shown to inhibit estrogen signaling in breast cancer and testicular tumors. However, the role of FXR in endometriosis is still poorly understood. Here, we aimed to investigate whether FXR activation by its synthetic agonist GW4064 has a therapeutic effect on endometriosis and the underlying molecular mechanisms. We found that the expression of FXR (encoded by the NR1H4 gene) in endometriotic tissues and stromal cells (ESCs) was higher than that in eutopic endometrial tissues and stromal cells. The GW4064 treatment led to a dose-dependent decrease in aromatase and estrogen receptor β (ERβ) expression and induced ERK1/2, p38, AMPK, and Stat3 activation in ESCs. In contrast, ERK1/2 inhibitor reversed the GW4064-induced reduction in aromatase expression. In addition, treatment with p38, AMPK, and Stat3 inhibitors or small interfering RNAs could also reverse the GW4064-induced reduction of ERβ expression in ESCs. The GW4064 treatment markedly increased Stat3 phosphorylation, enhancing the binding of Stat3 to the ESR2 promoter, which resulted in the downregulation of ERβ. Coimmunoprecipitation assay and chromatin immunoprecipitation analysis revealed that FXR was able to compete with cyclic AMP response element-binding (CREB) protein for binding to a common sequence on the aromatase promoter region after GW4064 treatment in ESCs. Moreover, treatment of endometriosis xenografts with GW4064 suppressed aromatase and ERβ expression in nude mice. Our results suggest that FXR may represent a potential therapeutic target for future therapy.

SULFATION PATHWAYS: Contribution of intracrine oestrogens to the aetiology of endometriosis

Endometriosis is an incurable hormone-dependent inflammatory disease that causes chronic pelvic pain and infertility characterized by implantation and growth of endometrial tissue outside the uterine cavity. Symptoms have a major impact on the quality of life of patients resulting in socioeconomic, physical and psychological burdens. Although the immune system and environmental factors may play a role in the aetiology of endometriosis, oestrogen dependency is still considered a hallmark of the disorder. The impact of oestrogens such as oestrone and particularly, oestradiol, on the endometrium or endometriotic lesions may be mediated by steroids originating from ovarian steroidogenesis or local intra-tissue production (intracrinology) dependent upon the expression and activity of enzymes that regulate oestrogen biosynthesis and metabolism. Two key pathways have been implicated: while there is contradictory data on the participation of the aromatase enzyme (encoded by CYP19A1), there is increasing evidence that the steroid sulphatase pathway plays a role in both the aetiology and pathology of endometriosis. In this review, we consider the evidence related to the pathways leading to oestrogen accumulation in endometriotic lesions and how this might inform the development of new therapeutic strategies to treat endometriosis without causing the undesirable side effects of current regimes that suppress ovarian hormone production.

Aromatase as a target for treating endometriosis

Endometriosis is a common gynecological disease that causes various clinical symptoms, such as chronic pelvic pain, dysmenorrhea and infertility, seriously affecting women's health and their quality of life. The symptoms and endometriotic lesions are relieved, in many cases, after menopause, when estrogen levels are lowered. Therefore, endometriosis is considered to be estrogen-dependent. Aromatase, the enzyme responsible for the last step of estrogen biosynthesis converting testosterone and androgen to estrogen, was previously reported to be more abundant in endometriotic tissues than in the normal endometrium, leading to an increased local estrogen concentration. Therefore, aromatase is considered a key therapeutic target for regulating local estrogen biosynthesis in endometriosis. A more complete understanding of the mechanisms that modulate aromatase and its activity is required to develop novel estrogen-targeted therapies for endometriosis. In this review article, we outline the current understanding of the pathological processes involved in estrogen production in endometriosis and propose novel strategies to treat this disorder.

Transcription factor 21 regulates expression of ERβ and SF-1 via upstream stimulatory factor-2 in endometriotic tissues

Steroidogenic factor-1 (SF-1, encoded by NR5A1) and estrogen receptor beta (ERβ, encoded by ESR2), which are highly expressed in endometriotic stromal cells (ESCs), contribute to the pathogenesis of endometriosis, but the regulation mechanism remains largely unknown. Transcription factor 21 (TCF21) belongs to the helix-loop-helix (bHLH) family characterized by regulating gene expression via binding to E-box element. Here, we attempted to determine the molecular mechanism of TCF21 on SF-1 and ERβ expression in endometriosis. We found that TCF21 expression in ESCs was higher than that in endometrial stromal cells (EMs), and positively correlated with SF-1 and ERβ expression in ESCs. Since the importance of E-box element for NR5A1 promoter activity has been previously reported, we performed site-mutation and luciferase assay, revealing that the E-box sequence in the ESR2 promoter is also a critical element modulating ERβ expression. Upstream stimulatory factor 2 (USF2) is another bHLH factor implicated in transcriptional regulation. Further analyses elucidated that it is not TCF21, but USF2 exhibited higher binding affinities in ESCs to NR5A1 and ESR2 promoters than in EMs. Additionally, TCF21 knockdown significantly decreased the binding activities of USF2 to NR5A1 and ESR2 promoters via disruption of the TCF21-USF2 complex. Meanwhile, manipulating TCF21 expression significantly affected MMP9 and cyclinD1 expression, as wells as proliferation and invasion of ESCs. Moreover, TCF21 depletion in endometriotic xenografts reduced SF-1 and ERβ expression, abrogating ectopic lesion growth in mice. Cumulatively, a critical role of TCF21 in the pathogenesis of endometriosis is demonstrated, suggesting a potential druggable target for future therapy.

Phthalates Exert Multiple Effects on Leydig Cell Steroidogenesis

Humans are significantly exposed to phthalates via food packaging, cosmetics and medical devices such as tubings and catheters. Testicular Leydig cells (LCs) are suggested to be among the main targets of phthalate toxicity in the body. However, their sensitivity to phthalates is species-dependent. This paper describes the response of the LCs from different species (mouse, rat and human) to phthalate exposure in different experimental paradigms (in vivo, ex vivo and in vitro), with particular focus on mechanisms of phthalate action on LC steroidogenesis. A comprehensive analysis of the impact of phthalate diesters and phthalate monoesters on LCs in different stages of their development is presented and possible mechanisms of phthalates action are discussed. Finally novel, not yet fully elucidated sites of action of phthalate monoesters on the backdoor pathway of 5α-dihydrotestosterone biosynthesis in immature mouse LCs and their effects on steroidogenesis and redox state in adult mouse LCs are reported.

An evolutionary conserved interaction between the Gcm transcription factor and the SF1 nuclear receptor in the female reproductive system

NR5A1 is essential for the development and for the function of steroid producing glands of the reproductive system. Moreover, its misregulation is associated with endometriosis, which is the first cause of infertility in women. Hr39, the Drosophila ortholog of NR5A1, is expressed and required in the secretory cells of the spermatheca, the female exocrine gland that ensures fertility by secreting substances that attract and capacitate the spermatozoids. We here identify a direct regulator of Hr39 in the spermatheca: the Gcm transcription factor. Furthermore, lack of Gcm prevents the production of the secretory cells and leads to female sterility in Drosophila. Hr39 regulation by Gcm seems conserved in mammals and involves the modification of the DNA methylation profile of mNr5a1. This study identifies a new molecular pathway in female reproductive system development and suggests a role for hGCM in the progression of reproductive tract diseases in humans.

Selective Estrogen-Receptor Modulators and Aromatase Inhibitors: Promising New Medical Therapies for Endometriosis?

Endometriosis is an estrogen-dependent disease and estrogen-related pathways are imbalanced in women with endometriosis. One of the key enzymes in estrogen synthesis is aromatase. Inhibiting this pathway at several points is a promising idea for the treatment of endometriosis. The third generation of aromatase inhibitors is becoming more potent in efficacy, with fewer side effects than previous generations, but cotreatment with other hormones is needed to inhibit ovarian stimulation. Other components that promote estrogen synthesis such as COX-2 can also be potentially targeted. Selective estrogen-receptor modulators could also be interesting in view of their tissue-specific effect. However, all these new drugs are still in an early phase of development. At present, it is too early to conclude that aromatase inhibitors, COX-2 inhibitors or selective estrogen-receptor modulators really present any added value compared with the existing drugs that can be used to achieve hormonal suppression in the medical treatment of endometriosis.

Identification of male-biased microRNA-107 as a direct regulator for nuclear receptor subfamily 5 group A member 1 based on sexually dimorphic microRNA expression profiling from chicken embryonic gonads

Several studies indicate that sexual dimorphic microRNAs (miRNAs) in chicken gonads are likely to have important roles in sexual development, but a more global understanding of the roles of miRNAs in sexual differentiation is still needed. To this end, we performed miRNA expression profiling in chicken gonads at embryonic day 5.5 (E5.5). Among the sex-biased miRNAs validated by qRT-PCR, twelve male-biased and six female-biased miRNAs were consistent with the sequencing results. Bioinformatics analysis revealed that some sex-biased miRNAs were potentially involved in gonadal development. Further functional analysis found that over-expression of miR-107 directly inhibited nuclear receptor subfamily 5 group A member 1 (NR5a1), and its downstream cytochrome P450 family 19 subfamily A, polypeptide 1 (CYP19A1). However, anti-Mullerian hormone (AMH) was not directly or indirectly regulated by miR-107. Overall results indicate that miR-107 may specifically mediate avian ovary-development by post-transcriptional regulation of NR5a1 and CYP19A1 in estrogen signaling pathways.

PRL-3 Is Involved in Estrogen- and IL-6-Induced Migration of Endometrial Stromal Cells From Ectopic Endometrium

OBJECTIVE

To investigate the role of phosphatase of regenerating liver-3 (PRL-3) in the 17β-estradiol (E2)- and interleukin 6 (IL-6)-induced migration of endometrial stromal cells (ESCs) from ectopic endometrium.

METHODS

Ectopic endometrial tissues were collected from patients with endometriosis, and PRL-3 expression in ectopic and eutopic endometrium was examined by immunohistochemistry. Endometrial stromal cells isolated from ectopic endometrium were treated with E2, progesterone (P), IL-6, or sodium orthovanadate (Sov) to inhibit PRL-3. Total RNA and protein were extracted from ESCs after treatment for quantitative real-time polymerase chain reaction and Western blot analyses. Cell migration was assessed using a scratch wound assay.

RESULTS

Phosphatase of regenerating liver 3 protein was highly expressed in the endometrial glandular cells (EGCs) and ESCs in ectopic endometrium, whereas its weak expression was observed only in EGCs in eutopic endometrium. Both E2 and IL-6 treatment significantly increased PRL-3 messenger RNA and protein expression, and P treatment significantly inhibited PRL-3 expression. However, E2-induced PRL-3 expression in ESCs from ectopic endometrium was significantly blocked by IL-6 antibody. Moreover, E2- and IL-6-enhanced cell migration was completely abrogated by Sov treatment. Furthermore, Sov treatment could significantly promote PTEN expression but inhibit E2- and IL-6-induced p-AKT activation.

CONCLUSION

Phosphatase of regenerating liver 3 plays a key role in the E2- and IL-6-induced migration of ESCs from ectopic endometrium, a process that is involved in the PTEN-AKT signaling pathway.

DNA methylation in endometriosis (Review)

Endometriosis is defined by the presence and growth of functional endometrial tissue, outside the uterine cavity, primarily in the ovaries, pelvic peritoneum and rectovaginal septum. Although it is a benign disease, it presents with malignant characteristics, such as invasion to surrounding tissues, metastasis to distant locations and recurrence following treatment. Accumulating evidence suggests that various epigenetic aberrations may play an essential role in the pathogenesis of endometriosis. Aberrant DNA methylation represents a possible mechanism repsonsible for this disease, linking gene expression alterations observed in endometriosis with hormonal and environmental factors. Several lines of evidence indicate that endometriosis may partially be due to selective epigenetic deregulations influenced by extrinsic factors. Previous studies have shed light into the epigenetic component of endometriosis, reporting variations in the epigenetic patterns of genes known to be involved in the aberrant hormonal, immunologic and inflammatory status of endometriosis. Although recent studies, utilizing advanced molecular techniques, have allowed us to further elucidate the possible association of DNA methylation with altered gene expression, whether these molecular changes represent the cause or merely the consequence of the disease is a question which remains to be answered. This review provides an overview of the current literature on the role of DNA methylation in the pathophysiology and malignant evolution of endometriosis. We also provide insight into the mechanisms through which DNA methylation-modifying agents may be the next step in the research of the pharmaceutical treatment of endometriosis.

Dysfunction of Liver Receptor Homolog-1 in Decidua: Possible Relevance to the Pathogenesis of Preeclampsia

Preeclampsia (PE) is a multisystem disorder unique to Homo sapiens that is known to cause maternal and perinatal mortality and morbidity. Between 5–7% of all pregnancies are affected by PE and it is responsible for approximately 50,000 maternal deaths annually. The pathogenesis of PE remains poorly understood. However, the results of this study indicated that insufficient decidualization plays a significant role. NR5A1 and NR5A2 are orphan members of the Ftz-F1 subfamily of nuclear receptors and are involved in mammal follicular development, female reproduction, steroidogenesis, and decidualization. The expression of NR5A1 and NR5A2 in the human decidua and their functions during decidualization were investigated using in vitro cultured cells by real-time PCR, immunohistochemistry, western blotting, and siRNA techniques. The results demonstrated that the levels of NR5A2 mRNA and protein in the decidual tissues of women with PE were lower than those of normal pregnant women. However, the levels of NR5A1 mRNA and protein did not significantly differ between groups. The expression of NR5A2 was upregulated after in vitro decidualization, but the expression of NR5A1 remained low and showed no difference compared with that of the control cells. Knocking down of NR5A2 in human endometrial stromal cells (hESC) resulted in a significant reduction in their expression of decidualization markers (IGFBP1 and PRL) and signaling pathway molecules (WNT4 and BMP2) (P < 0.05). From these data, we concluded that NR5A2 is pivotal for the decidualization of decidual tissues and cultured human endometrial stromal cells. Disorders of the endometrium in decidual tissues may be associated with the abnormal decidualization thought to cause PE.

Animal Models in Endometriosis Research

The initiation of endometriosis in women is difficult to investigate, because there is usually a delay of several years from the onset of lesion development to the clinical diagnosis. Animal models of endometriosis, on the other hand, provide an important contribution to the investigation of the disease pathogenesis and the efficacy of therapeutic intervention strategies.

Metformin Suppresses Prostaglandin E2-Induced Cytochrome P450 Aromatase Gene Expression and Activity via Stimulation of AMP-Activated Protein Kinase in Human Endometriotic Stromal Cells

BACKGROUND

Cytochrome P450 aromatase (encoded by the CYP19A1/aromatase gene) plays a critical physiologic role in endometriosis. Metformin is known to suppress prostaglandin E2 (PGE2)-induced CYP19A1 messenger RNA (mRNA) expression in human endometriotic stromal cells (ESCs). However, the possible mechanism behind this suppression remains to be determined.

METHODS

In this study, ESCs were cultured with metformin, PGE2, and adenosine monophosphate (AMP)-activated protein kinase (AMPK) inhibitors. Expression of CYP19A1 mRNA and aromatase activity were measured by quantitative polymerase chain reaction and aromatase activity assay, respectively. The binding of the cyclic AMP response element-binding (CREB) protein to CYP19A1 promoter II (PII) was assessed by chromatin immunoprecipitation assay.

RESULTS

We demonstrated that metformin downregulated the expression of aromatase mRNA (32%) and activity (25%) stimulated by PGE2 (4.18-fold and 2.14-fold) in ESCs via stimulation of AMPK. Following PGE2 treatment, there was a marked increase in CREB binding to aromatase PII, while metformin attenuated the above-mentioned stimulation by 67%.

CONCLUSION

Metformin could inhibit PGE2-induced CYP19A1 mRNA expression and aromatase activity via AMPK activation and inhibition of CREB to CYP19A1 PII in human ESCs. The results of the present study suggest that metformin may have unique therapeutic potential as an antiendometriotic drug in the future.

A low-testosterone state associated with endometrioma leads to the apoptosis of granulosa cells

Although endometriosis is suspected to be a cause of premature ovarian insufficiency (POI), the mechanism(s) underlying this process have not been elucidated. Recently, androgens were shown to promote oocyte maturation and to play a role in folliculogenesis. In addition, several reports have documented low testosterone levels in the follicular fluid obtained from endometriosis patients. We therefore examined whether the low levels of serum testosterone are associated with the apoptosis of granulosa cells in follicles obtained from endometriosis patients. Serum samples were collected from 46 patients with endometriosis and from 62 patients without endometriosis who received assisted reproductive therapy. Specimens of the ovaries obtained from 10 patients with endometrioma were collected using laparoscopy. The mean serum testosterone concentration in the patients with endometriosis was significantly lower than that observed in the patients without endometriosis. Furthermore, high expression of a pro-apoptotic Bcl-2 member, BimEL, in the follicles was found to be associated with a low serum testosterone level. We clarified the underlying mechanisms using a basic approach employing human immortalized granulosa cells derived from a primary human granulosa cell tumor, the COV434 cell line. The in vitro examination demonstrated that testosterone inhibited apoptosis induced by sex steroids depletion via the PI3K/Akt-FoxO3a pathway in the COV434 cells. In conclusion, we elucidated the mechanism underlying the anti-apoptotic effects of testosterone on granulosa cells, and found that a low-testosterone status is a potentially important step in the development of premature ovarian insufficiency in patients with endometriosis.

TNIP1 reduction of HSPA6 gene expression occurs in promoter regions lacking binding sites for known TNIP1-repressed transcription factors

TNFα-induced protein 3-interacting protein 1 (TNIP1) represses signaling pathways initiated by specific nuclear and transmembrane receptors. This effect results in reduced activity of distinct transcription factors such as retinoic acid receptors (RAR), peroxisome-proliferator-activated receptors (PPAR), and NFκB. TNIP1-null and TNIP1-knockin defective for ubiquitin-binding mice show increased liver apoptosis, and enlarged spleen and lymph nodes, respectively. To complement current knowledge of TNIP1's broad physiologic functions as interpreted from in vivo studies and specific expression consequences from transcription factor repression, we determined effects of excess TNIP1 on global gene regulation. Following experimentally increased expression of TNIP1 in cultured keratinocytes, our gene expression microarray analysis not only confirmed TNIP1's association in previously known pathways and functions but also found a novel TNIP1-regulated pathway - the cell stress response. Under standard culture conditions, expression of several heat shock proteins, including HSPA1A, HSPA6, DNAJA1 and DNAJB1, was reduced. In heat-stressed conditions, differential regulation of HSPA1A and HSPA6 was observed, where only HSPA6 expression was reduced after heat-shock. Using HSPA6 as a model to elucidate the mechanism of the TNIP1-mediated HSP repression, we determined that TNIP1 likely represses HSPs through factors other than RAR, PPAR or NFκB despite the presence of these factors' binding sites in the HSPA6 promoter. These results indicate that regulation of HSPs may be through a yet unknown TNIP1-associated pathway. Additionally, these results suggest that TNIP1's reduction of HSP expression levels could negatively impact HSP chaperone capacity or their participation in the cell stress response.

The p160/steroid receptor coactivator family: potent arbiters of uterine physiology and dysfunction

The p160/steroid receptor coactivator (SRC) family comprises three pleiotropic coregulators (SRC-1, SRC-2, and SRC-3; otherwise known as NCOA1, NCOA2, and NCOA3, respectively), which modulate a wide spectrum of physiological responses and clinicopathologies. Such pleiotropy is achieved through their inherent structural complexity, which allows this coregulator class to control both nuclear receptor and non-nuclear receptor signaling. As observed in other physiologic systems, members of the SRC family have recently been shown to play pivotal roles in uterine biology and pathobiology. In the murine uterus, SRC-1 is required to launch a full steroid hormone response, without which endometrial decidualization is markedly attenuated. From "dovetailing" clinical and mouse studies, an isoform of SRC-1 was recently identified which promotes endometriosis by reprogramming endometrial cells to evade apoptosis and to colonize as endometriotic lesions within the peritoneal cavity. The endometrium fails to decidualize without SRC-2, which accounts for the infertility phenotype exhibited by mice devoid of this coregulator. In related studies on human endometrial stromal cells, SRC-2 was shown to act as a molecular "pacemaker" of the glycolytic flux. This finding is significant because acceleration of the glycolytic flux provides the necessary bioenergy and biomolecules for endometrial stromal cells to switch from quiescence to a proliferative phenotype, a critical underpinning in the decidual progression program. Although studies on uterine SRC-3 function are in their early stages, clinical studies provide tantalizing support for the proposal that SRC-3 is causally linked to endometrial hyperplasia as well as with endometrial pathologies in patients diagnosed with polycystic ovary syndrome. This proposal is now driving the development and application of innovative technologies, particularly in the mouse, to further understand the functional role of this elusive uterine coregulator in normal and abnormal physiologic contexts. Because dysregulation of this coregulator triad potentially presents a triple threat for increased risk of subfecundity, infertility, or endometrial disease, a clearer understanding of the individual and combinatorial roles of these coregulators in uterine function is urgently required. This minireview summarizes our current understanding of uterine SRC function, with a particular emphasis on the next critical questions that need to be addressed to ensure significant expansion of our knowledge of this underexplored field of uterine biology.

Estrogen receptor (ER) agonists differentially regulate neuroangiogenesis in peritoneal endometriosis via the repellent factor SLIT3

Endometriosis is an estrogen-dependent neurovascular disorder characterized by growth of endometrial tissue (lesions) outside the uterine cavity. Patients suffer chronic pelvic pain, and it has been proposed that co-recruitment of nerves/blood vessels (neuroangiogenesis) into the lesions is fundamental to the development of painful symptoms. We hypothesized that estrogen-dependent regulation of axonal guidance molecules of the SLIT/ROBO (Roundabout) family could play a role in neuroangiogenesis occurring in endometriosis lesions found on the peritoneal wall. In tissue samples from human patients and a mouse model of endometriosis, concentrations of mRNA encoded by SLIT3 were significantly higher in lesions than normal peritoneum. Estrogen regulation of SLIT3 was investigated using 17β-estradiol and selective agonists for each subtype of estrogen receptor (ER) (ERα agonist, 4,4',4″-(4-propyl-(1H)-pyrazole-1,3,5-tryl) trisphenol; ERβ agonist, 2,3-bis(4-hydroxy-phenyl)-propionitrile [DPN]). In mice, DPN (EC50 0.85) increased Slit3 mRNA concentrations compared with hormone-depleted and 17β-estradiol-treated (EC50 0.1) animals and decreased the density of nerves but not vessels in endometriosis lesions. SLIT3 mRNA concentrations were increased in DPN-treated human endometrial endothelial cells and in 4,4',4″-(4-propyl-(1H)-pyrazole-1,3,5-tryl) trisphenol-treated (EC50 200) rat dorsal root ganglia neurons. Functional assays (neurite outgrowth, network formation) revealed that SLIT3 promotes angiogenesis but decreases neurogenesis. In conclusion, these data suggest that estrogen-dependent expression of SLIT3 may play a key role in regulating nerve-vessel interactions within the complex microenvironment of endometriosis lesions.

Peroxisome proliferator-activated receptor gamma, coactivator 1α enhances local estrogen biosynthesis by stimulating aromatase activity in endometriosis

CONTEXT

Endometriosis is an estrogen-dependent disease, and estrogen is overproduced by abnormally elevated aromatase in endometriotic tissues. Peroxisome proliferator-activated receptor gamma, coactivator 1α (PGC-1α) is a transcriptional coactivator-modulating steroid hormone.

OBJECTIVE

To investigate the effect of PGC-1α on aromatase activity in endometriosis.

DESIGN

Specimens from ovarian endometrioma (OE), endometrium with endometriosis (EE), and normal endometrium (NE) were analyzed for PGC-1α and aromatase expression. PGC-1α-dependent changes in aromatase expression in primary cultured stromal cells (SCs) were identified using luciferase and enzymatic assays, exon I-specific RT-PCR, and real-time PCR. Environmental stimulus-induced changes in PGC-1α were also examined.

RESULTS

PGC-1α was more highly expressed in OE than in EE and NE (P < .01). In OE, PGC-1α was coexpressed with aromatase, and their mRNA expressions were also correlated (r = 0.56, P = .02). PGC-1α was recruited to the nuclear receptor half-site between PI.3 and PII in the aromatase promoter. PGC-1α overexpression enhanced aromatase promoter activity (P < .01), mRNA expression (P < .05), and enzymatic activity (P < .01) in SCs from OE, but not in SCs from EE or NE. The levels of PI.3, PII, and exon II mRNA increased and transcriptional enhancement was abolished by mutation of the PGC-1α-interacting site. PGC-1α expression was enhanced in SCs from OE by tumor necrosis factor (TNF)-α (P < .05) but not by hypoxia or 17β-estradiol.

CONCLUSIONS

PGC-1α stimulated by TNF-α regulates aromatase expression and activity to promote local estrogen biosynthesis in OE, suggesting that PGC-1α is a promising candidate for novel targeted therapies in endometriosis treatment.

Molecular aspects of development and regulation of endometriosis

Endometriosis is a common and painful condition affecting women of reproductive age. While the underlying pathophysiology is still largely unknown, much advancement has been made in understanding the progression of the disease. In recent years, a great deal of research has focused on non-invasive diagnostic tools, such as biomarkers, as well as identification of potential therapeutic targets. In this article, we will review the etiology and cellular mechanisms associated with endometriosis as well as the current diagnostic tools and therapies. We will then discuss the more recent genomic and proteomic studies and how these data may guide development of novel diagnostics and therapeutics. The current diagnostic tools are invasive and current therapies primarily treat the symptoms of endometriosis. Optimally, the advancement of "-omic" data will facilitate the development of non-invasive diagnostic biomarkers as well as therapeutics that target the pathophysiology of the disease and halt, or even reverse, progression. However, the amount of data generated by these types of studies is vast and bioinformatics analysis, such as we present here, will be critical to identification of appropriate targets for further study.

Suppression of COUP-TFII by proinflammatory cytokines contributes to the pathogenesis of endometriosis

CONTEXT

Endometriosis is one of the most common gynecological diseases in women with a prevalence rate of approximately 10%. Chronic pelvic inflammation has been observed in patients with endometriosis and is associated with disease severity. However, how pelvic inflammation promotes endometriosis progression remains unknown.

OBJECTIVE

The objective of the study was to investigate the regulatory network of proinflammatory cytokines in endometriosis progression.

DESIGN, SETTINGS, AND PATIENTS

Immunostaining of human endometrial (n = 21) and endometriotic (n = 36) sections, quantitative RT-PCR, Western blotting, chromatin immunoprecipitation, and luciferase reporter assays in primary culture human endometrial stromal cells were performed. Autologous transplantation of uterine endometrium from control chicken ovalbumin upstream promoter-transcription factor II [(COUP-TFII) flox/flox] and uterus-specific COUP-TFII knockout mice was performed.

RESULTS

Expression of COUP-TFII was significantly reduced in endometriotic stroma. Reduction of COUP-TFII in endometriotic stromal cells was mediated by proinflammatory cytokines including IL-1β, TNF-α, and TGF-β1 via a common effector, microRNA-302a. Treatment with these proinflammatory cytokines increased the expression of microRNA-302a, which targets the 3'untranslated region of COUP-TFII to cause its down-regulation. Intriguingly, down-regulation of COUP-TFII in endometrial stromal cells resulted in de-repression of cyclooxygenase-2 (COX-2). Further investigation demonstrated that COUP-TFII directly binds to COX-2 promoter to inhibit its transcription. Forced expression of COUP-TFII inhibited IL-1β-induced COX-2 up-regulation, whereas the knockdown of COUP-TFII augmented this effect.

CONCLUSION

Because overexpression of COX-2 has been demonstrated to be a master regulator in endometriosis progression, our data demonstrate the critical function of proinflammatory cytokines and the COUP-TFII regulatory gene network in the progression of endometriosis.

Steroidogenic factor 1 promotes aggressive growth of castration-resistant prostate cancer cells by stimulating steroid synthesis and cell proliferation

The dependence of prostate cancer on androgens provides a targeted means of treating advanced disease. Unfortunately, androgen deprivation therapies eventually become ineffective, leading to deadly castration-resistant prostate cancer (CRPC). One of many factors implicated in the transition to CRPC is the onset of de novo steroidogenesis. Although reactivation of steroid receptors likely plays a pivotal role in aggressive CRPC, little is understood regarding the mechanisms whereby prostate cancer cells initiate and maintain steroidogenesis. We hypothesize that steroidogenic factor 1 (SF1, NR5A1, AD4BP), a key regulator of steroidogenesis in normal endocrine tissues, is expressed in CRPC where it stimulates aberrant steroidogenesis and fuels aggressive growth. Notably, SF1 is not expressed in normal prostate tissue. Our results indicated that SF1 was absent in benign cells but present in aggressive prostate cancer cell lines. Introduction of ectopic SF1 expression in benign human prostate epithelial cells (BPH-1) stimulated increased steroidogenic enzyme expression, steroid synthesis, and cell proliferation. In contrast, data from an aggressive human prostate cancer cell line (BCaPT10) demonstrated that SF1 was required for steroid-mediated cell growth because BCaPT10 cell growth was diminished by abiraterone treatment and short hairpin RNA-mediated knockdown of SF1 (shSF1). SF1-depleted cells also exhibited defective centrosome homeostasis. Finally, whereas xenograft experiments in castrated hosts with BCaPT10 control transplants grew large, invasive tumors, BCaPT10-shSF1 knockdown transplants failed to grow. Therefore, we conclude that SF1 stimulates steroid accumulation and controls centrosome homeostasis to mediate aggressive prostate cancer cell growth within a castrate environment. These findings present a new molecular mechanism and therapeutic target for deadly CRPC.

COUP-TFII regulates human endometrial stromal genes involved in inflammation

Chicken ovalbumin upstream promoter-transcription factor II (COUP-TFII; NR2F2) is an orphan nuclear receptor involved in cell-fate specification, organogenesis, angiogenesis, and metabolism. Ablation of COUP-TFII in the mouse uterus causes infertility due to defects in embryo attachment and impaired uterine stromal cell decidualization. Although the function of COUP-TFII in uterine decidualization has been described in mice, its role in the human uterus remains unknown. We observed that, as in mice, COUP-TFII is robustly expressed in the endometrial stroma of healthy women, and its expression is reduced in the ectopic lesions of women with endometriosis. To interrogate the role of COUP-TFII in human endometrial function, we used a small interfering RNA-mediated loss of function approach in primary human endometrial stromal cells. Attenuation of COUP-TFII expression did not completely block decidualization; rather it had a selective effect on gene expression. To better elucidate the role of COUP-TFII in endometrial stroma cell biology, the COUP-TFII transcriptome was defined by pairing microarray comparison with chromatin immunoprecipitation followed by deep sequencing. Gene ontology analysis demonstrates that COUP-TFII regulates a subset of genes in endometrial stroma cell decidualization such as those involved in cell adhesion, angiogenesis, and inflammation. Importantly this analysis shows that COUP-TFII plays a role in controlling the expression of inflammatory cytokines. The determination that COUP-TFII plays a role in inflammation may add insight into the role of COUP-TFII in embryo implantation and in endometrial diseases such as endometriosis.

Methylation of a novel CpG island of intron 1 is associated with steroidogenic factor 1 expression in endometriotic stromal cells

Steroidogenic factor 1 (SF-1), a transcriptional factor essential for estrogen biosynthesis, is undetectable in endometrial stromal cells and aberrantly expressed in endometriotic stromal cells.

OBJECTIVE

We tried to gain further insight into the mechanism for differential SF-1 expression in endometrial and endometriotic stromal cells.

DESIGN

We had previously identified a novel CpG island in SF-1, which is located in the downstream intron 1 region. Here, we evaluated the methylation status of this CpG island.

PATIENTS

We obtained the eutopic endometrium from disease-free participants (n = 8) and the walls of cystic endometriosis lesions of the ovaries from another group of participants (n = 8). None of the patients had received any preoperative hormonal therapy.

INTERVENTIONS

Stromal cells were isolated from these 2 types of tissues and subjected to DNA bisulfite treatment and sequence analysis.

RESULTS

The SF-1 messenger RNA (mRNA) levels in endometriotic stromal cells were significantly higher than those in endometrial stromal cells. Bisulfite sequencing showed strikingly increased methylation of a 1-kbp region around the previously identified CpG island in endometriotic cells compared with endometrial cells (P < .001). A strong correlation between SF-1 mRNA levels and percentage methylation of the intron 1 region of the SF-1 gene was observed in endometriotic cells (Spearman correlation coefficient, .96; P < .001).

CONCLUSIONS

Methylation of the intron 1 region of the SF-1 gene is associated with its expression in endometriotic cells. This CpG island therefore plays an important role in regulating SF-1 expression.

Expression and functional pathway analysis of nuclear receptor NR2F2 in ovarian cancer

CONTEXT

Recent evidence implicates the orphan nuclear receptor, nuclear receptor subfamily 2, group F, member 2 (NR2F2; chicken ovalbumin upstream promoter-transcription factor II) as both a master regulator of angiogenesis and an oncogene in prostate and other human cancers.

OBJECTIVE

The objective of the study was to determine whether NR2F2 plays a role in ovarian cancer and dissect its potential mechanisms of action.

DESIGN, SETTING, AND PATIENTS

We examined NR2F2 expression in healthy ovary and ovarian cancers using quantitative PCR and immunohistochemistry. NR2F2 expression was targeted in established ovarian cancer cell lines to assess the impact of dysregulated NR2F2 expression in the epithelial compartment of ovarian cancers.

RESULTS

Our results indicate that NR2F2 is robustly expressed in the stroma of healthy ovary with little or no expression in epithelia lining the ovarian surface, clefts, or crypts. This pattern of NR2F2 expression was markedly disrupted in ovarian cancers, in which decreased levels of stromal expression and ectopic epithelial expression were frequently observed. Ovarian cancers with the most disrupted patterns of NR2F2 were associated with significantly shorter disease-free interval by Kaplan-Meier analysis. Targeting NR2F2 expression in established ovarian cancer cell lines enhanced apoptosis and increased proliferation. In addition, we found that NR2F2 regulates the expression of NEK2, RAI14, and multiple other genes involved in the cell cycle, suggesting potential pathways by which dysregulated expression of NR2F2 impacts ovarian cancer.

CONCLUSIONS

These results uncover novel roles for NR2F2 in ovarian cancer and point to a unique scenario in which a single nuclear receptor plays potentially distinct roles in the stromal and epithelial compartments of the same tissue.

MicroRNA23a and microRNA23b deregulation derepresses SF-1 and upregulates estrogen signaling in ovarian endometriosis

CONTEXT

Steroidogenic factor (SF)-1 and its downstream target genes involved in estrogen signaling are aberrantly expressed in ovarian endometriosis.

OBJECTIVE

Our objective was to explore the microRNA-mediated mechanism controlling aberrant SF-1 expression in ovarian endometriosis.

DESIGN

Bioinformatics analysis predicted that microRNA23a and microRNA23b (miR23a/b) target the NR5A1 3'-untranslated region. We investigated the relative expression and spatial distribution of miR23a/b and analyzed the relationship between miR23a/b and SF-1 expression in endometriotic tissues.

SETTING

The study was conducted at the Department of Gynecology and Obstetrics, West China Second University Hospital of Sichuan University.

PATIENTS OR OTHER PARTICIPANTS

We enrolled 23 women with American Fertility Society stage III-IV ovarian endometriosis and 15 disease-free control subjects.

INTERVENTIONS

Quantitative real-time RT-PCR, in situ hybridization, cell culture, transfections, and luciferase reporter assays were used in this study.

MAIN OUTCOME MEASURES

The expression of miR23a/b and SF-1, CYP19A1, and StAR mRNAs; the relationships between miRNAs and SF-1 mRNA levels; and the effect of miR23a/b on SF-1 expression were measured in normal and eutopic endometrial stromal cells (ESCs) and 293T cells.

RESULTS

Both miR23a and miR23b were downregulated in ectopic and eutopic endometrium, compared with normal endometrium, and their expression was inversely correlated with NR5A1 mRNA levels. SF-1 expression was inhibited by miR23a/b overexpression in eutopic ESCs and upregulated by miR23a/b inhibition in normal ESCs.

CONCLUSIONS

MiR23a and miR23b are potential biomarkers of ovarian endometriosis. This study provides a novel approach for targeting the mechanisms controlling aberrant local estrogen biosynthesis in endometriosis.

Effects of ectopic HER-2/neu gene expression on the COX-2/PGE2/P450arom signaling pathway in endometrial carcinoma cells: HER-2/neu gene expression in endometrial carcinoma cells

Objectives

To investigate the role of HER-2/neu-mediated COX-2/P450arom signal in estrogen-dependent endometrial carcinoma.

Methods

The recombinant eukaryotic expression vector, pcDNA3.1-HER-2/neu, was constructed and transfect to Ishikawa endometrial carcinoma cells. The expression of COX-2 and P450arom in transfected cells were detected by real-time PCR and western blotting. The levels of estrogen in cell supernatants were detected by ELISA.

Results

Over-expression of HER-2/neu in transfected cells was confirmed by real-time PCR and western blotting. The levels of autocrine estrogen in transfected cells was significantly increased which combination with the enhancement of COX-2 and P450arom expression in transfected cells.

Conclusion

HER-2/neu induced the improvement of autocrine estrogen in endometrial carcinoma cell through triggering the COX-2/P450arom signal.

The expression status of G protein-coupled receptor GPR30 is associated with the clinical characteristics of endometriosis

INTRODUCTION

GPR30 is a seven-transmembrane G protein-coupled estrogen receptor that regulates endometrial cellular responses to estrogen. GPR30 is often highly expressed in cancer cells from aggressive tumors. The aim of this study was to evaluate the expression patterns of GPR30 in endometriosis during medical treatment.

PATIENTS

A total of 38 females, 28 patients with endometriosis and 10 patients with leiomyoma who underwent laparoscopic surgery were included this study.

INTERVENTION

Eutopic endometrial tissue sampling from women without endometriosis and ectopic endometrial tissue sampling from women with endometriosis.

MAIN OUTCOME MEASURE

A quantitative real-time polymerase chain reaction analysis of the mRNA expression in eutopic and ectopic endometrial tissues with or without GnRH agonist treatment. The expression of GPR30 was confirmed by immunohistochemistry.

RESULTS

There was an increased level of GPR30 mRNA in eutopic endometrium during the proliferative phase, whereas higher expression was observed in the ectopic endometrium during the secretory phase. Increased GPR30 mRNA was observed in ectopic endometrium in comparison to eutopic endometrium. GnRH agonist treatment before laparoscopic surgery decreased GPR30 mRNA in ectopic endometrium. The immunohistochemical analysis also revealed that GPR30 was strongly expressed in epithelial cells in ectopic endometrium, whereas GnRH agonist treatment decreased the GPR30 expression.

CONCLUSION

High levels of GPR30 expression can play an important role in the progression of endometriosis.

Multiple roles of COUP-TFII in cancer initiation and progression

Chicken ovalbumin upstream promoter transcription factor II (COUP-TFII) is an orphan nuclear receptor that acts as a transcriptional activator or repressor in a cell type-dependent manner. Best characterized for its role in the regulation of angiogenesis during mouse development, COUP-TFII also plays important roles in glucose metabolism and cancer. Expression of COUP-TFII is altered in various endocrine conditions. Cell type-specific functions and the regulation of COUP-TFII expression result in its varying physiological and pathological actions in diverse systems. Evidence will be reviewed for oncogenic and tumor-suppressive functions of COUP-TFII, with roles in angiogenesis, metastasis, steroidogenesis, and endocrine sensitivity of breast cancer described. The applicability of current data to our understanding of the role of COUP-TFII in cancer will be discussed.