Primary Human Endometrial Stromal Cells Research Articles

Loss of miR-542-3p enhances IGFBP-1 expression in decidualizing human endometrial stromal cells

Endometrial decidualization represents an essential step for the successful implantation of the embryo; however, the molecular mechanism behind this differentiation process remains unclear. This study aimed to identify novel microRNAs (miRNAs) involved in the regulation of decidual gene expression in human endometrial stromal cells (HESCs). An in vitro analysis of primary undifferentiated and decidualizing HESCs was conducted. HESCs were isolated from hysterectomy specimens from normally cycling premenopausal women with uterine fibroids, who were not on hormonal treatment at the time of surgery. Primary HESCs were expanded in culture and decidualized with 8-bromo-cyclic adenosine monophosphate and medroxyprogesterone acetate. Microarray analysis identified six miRNAs differentially expressed in response to decidualization of HESCs. All but one miRNA were downregulated upon decidualization, including miR-542-3p. We demonstrated that miR-542-3p overexpression inhibits the induction of major decidual marker genes, including IGFBP1, WNT4 and PRL. In addition, miR-542-3p overexpression inhibited the morphological transformation of HESCs in response to deciduogenic cues. A luciferase reporter assay confirmed that the 3′-untranslated region of IGFBP1 mRNA is targeted by miR-542-3p. The results suggest that miR-542-3p plays an important role in endometrial decidualization by regulating the expression of major decidual marker genes.

Role of Versican in the Pathogenesis of Peritoneal Endometriosis.

Sampson's theory cannot explain why only some cycling women develop peritoneal endometriosis. Few studies have focused on the pelvic peritoneum, which receives regurgitated endometrial tissues. We hypothesized that molecular alterations in the peritoneum are involved in the development of peritoneal endometriosis and conducted a microarray analysis to compare macroscopically normal peritoneum sampled from women with peritoneal endometriosis (endometriotic peritoneum) and those without (non-endometriotic peritoneum). Versican, a major proteoglycan component of the extracellular matrix, is one of the molecules up-regulated in endometriotic peritoneum. To investigate the role of versican in peritoneal endometriosis. Design, Patients, and Main Outcome Measure: Endometriotic peritoneum and non-endometriotic peritoneum were subjected to RT-PCR, immunostaining, and Western blotting. The versican V1 isoform was stably transfected into Chinese hamster ovary cells (CHO-V1), and the effects of CHO-V1-derived conditioned medium (V1-CM) on primary human endometrial stromal cells were investigated with attachment, invasion, and proliferation assays. The effects of peritoneal fluid collected from endometriotic women (endometriotic PF) or cytokines/growth factors, which were shown to be elevated in endometriotic PF, on versican expression in a human peritoneal cell line (HMrSV5) were also examined. Versican V1 expression levels were significantly higher in endometriotic peritoneum. In vitro, V1-CM promoted attachment to the HMrSV5 cell monolayer as well as the Matrigel invasion of endometrial stromal cells. Although versican V1 expression was up-regulated by TGF-β1 in HMrSV5 cells, it remained unchanged in endometriotic PF. Our results suggest the involvement of peritoneal versican in the development of peritoneal endometriosis.

1 sFlt1 production in human endometrial stromal cells is reversibly regulated during hormone stimulation and withdrawal

Introduction Preeclampsia is a major complication of pregnancy in which the placenta is known to have shallow implantation into the decidua. Studies have implicated sFlt1, a soluble vascular endothelial growth factor (VEGF) receptor protein, in the pathogenesis of preeclampsia through its ability to bind with VEGF and thereby neutralize its angiogenic functions. The presence of sFlt1 and its action in the endometrium is yet to be determined. We hypothesize that endometrial cells at the maternal–fetal interface may play a role in sFlt1 regulation during pregnancy. In this study, we are seeking to understand the dynamic regulation of sFlt1 production in human endometrial stromal cells (HESC) during reversible decidualization as a result of hormone stimulation and withdrawal. Aim To investigate the regulation of sFlt1 production in primary HESC during in an in vitro model of reversible decidualization that mimics the biphasic differentiation changes that occur during the ovulatory cycle. Methods Primary HESC were isolated and cultured according to published reports. Decidualization of HESC was induced either by adding a cocktail of estrogen, progesterone and cAMP (EPC) or cAMP alone for 4, 8 and 12 days. sFlt levels were assessed by Western blot or ELISA in the culture supernatant. sFlt1 mRNA expression was quantified by real-time RT-PCR. After decidualization, a subset of HESC were exposed to cocktail-free (no EPC) or cAMP free medium for 4, 8, and 12 days to study reversal of decidualization on sFlt1 expression. Results sFlt1 was detected in the culture supernatant of HESC. sFlt1 production decreased in a time-dependent manner during decidualization induced by the EPC cocktail and was totally abrogated after 12 days of treatment. This effect coincided with an increased production of VEGF and prolactin, and cellular morphologic changes characteristic of HESC decidualization. Upon hormonal and cAMP withdrawal, sFlt1 production began to increase in a time-dependent manner in concert with a reversal of decidualization as indicated by morphologic and biochemical criteria (e.g. prolactin and VEGF production). Although estrogen and progesterone are critical players during decidualization, our results indicated that cAMP is the dominant factor which regulates sFlt production. Conclusion HESC synthesize and secrete measurable quantities of sFlt1 that is downregulated during decidualization as a result of increased intracellular cAMP levels. With hormonal and cAMP withdrawal, sFlt1 production was regained, reflecting the plasticity of HESC. These findings may have important implications in diseases such as preeclampsia that involve abnormal decidualization and angiogenesis at the maternal-fetal interface. Studies are underway to understand the precise mechanisms of sFlt1 reduction by cAMP in the endometrium.

Endometrial Stromal Decidualization Responds Reversibly to Hormone Stimulation and Withdrawal.

Human endometrial stromal decidualization is required for embryo receptivity, angiogenesis, and placentation. Previous studies from our laboratories established that connexin (Cx)-43 critically regulates endometrial stromal cell (ESC) differentiation, whereas gap junction blockade prevents it. The current study evaluated the plasticity of ESC morphology and Cx43 expression, as well as other biochemical markers of cell differentiation, in response to decidualizing hormones. Primary human ESC cultures were exposed to 10 nM estradiol, 100 nM progesterone, and 0.5 mM cAMP for up to 14 days, followed by hormone withdrawal for 14 days, mimicking a biphasic ovulatory cycle. Reversible differentiation was documented by characteristic changes in cell shape. Cx43 was reversibly up- and down-regulated after the estradiol, progesterone, and cAMP treatment and withdrawal, respectively, paralleled by fluctuations in prolactin, vascular endothelial growth factor, IL-11, and glycodelin secretion. Markers of mesenchymal-epithelial transition (MET), and its counterpart epithelial-mesenchymal transition, followed reciprocal patterns corresponding to the morphological changes. Incubation in the presence of 18α-glycyrrhetinic acid, an inhibitor of gap junctions, partially reversed the expression of decidualization and MET markers. In the absence of hormones, Cx43 overexpression promoted increases in vascular endothelial growth factor and IL-11 secretion, up-regulated MET markers, and reduced N-cadherin, an epithelial-mesenchymal transition marker. The combined results support the hypothesis that Cx43-containing gap junctions and endocrine factors cooperate to regulate selected biomarkers of stromal decidualization and MET and suggest roles for both phenomena in endometrial preparation for embryonic receptivity.

MicroRNA-29b inhibits TGF-β1-induced fibrosis via regulation of the TGF-β1/Smad pathway in primary human endometrial stromal cells.

Transforming growth factor (TGF)-β1 has a key role in the regulation of fibrosis and organ dysfunction. During the pathogenesis and progression of vital organ fibrosis, the microRNA (miR)-29 family is irregularly downregulated and exogenous supplementation of miR-29b has a strong anti-fibrotic capacity. However, whether TGF-β1 is able to provoke endometrial fibrosis, and the role of miR-29 in endometrial fibrosis remain unclear. In the present study, RT-qPCR, immunocytochemistry, western blot analysis, scanning electron microscopy, immunofluorescence staining, cell proliferation assay and flow cytometric analysis were employed. The results demonstrated that the expression levels of collagen, type 1, alpha 1 (COL1A1), α-smooth muscle actin (α-SMA) and phosphorylated (p)-Smad2/3 were increased, whereas miR-29b and maternally expressed gene 3 (MEG3) were decreased in primary endometrial stromal cells (ESCs) in response to TGF-β1 stimulation, in a time and dose-dependent manner. Furthermore, overexpression of miR-29b markedly reduced the expression levels of COL1A1 and α-SMA, and decreased the expression and nuclear accumulation of p-Smad2/3. In addition, ectopic overexpression of miR-29b increased the expression levels of MEG3, inhibited myofibroblast-like cell proliferation and induced apoptosis. These findings indicated that miR-29b may have a significant anti-fibrotic role, and may attenuate TGF-β1-induced fibrosis in ESCs. Therefore, exogenous miR-29b may serve as a potential therapeutic agent for the treatment of endometrial fibrosis.

17 β-Estradiol promotes vascular endothelial growth factor expression via the Wnt/β-catenin pathway during the pathogenesis of endometriosis.

Do estrogen and Wnt/β-catenin signaling promote vascular endothelial growth factor (VEGF) expression in endometriosis and how? 17β-Estradiol (E2)-drives β-catenin triggered up-regulation of VEGF in effector human primary endometrial stromal cells (ESCs) and thus enhances their ability to establish a new blood supply to the human exfoliated endometrium. Implantation and survival of exfoliated endometrium is crucially dependent on neovascularization and Wnt/β-catenin signaling plays an important role in stimulating angiogenesis. Expression levels of VEGF mRNA, estrogen receptor α (ERα) and β-catenin protein were measured in ovarian endometriosis, eutopic endometrium of endometriosis patients and normal endometrium with real-time RT-PCR and western blot. ESCs were treated with 10 nM E2 for different times in order to evaluate the effect of E2 on ERα, β-catenin and VEGF expression in these cells. Human endometrial stromal cells (T HESCs) were cultured for transfection with expression vectors and siRNA constructs and used in chromatin immunoprecipitation (ChIP) and luciferase assays, which were conducted to clarify the regulation mechanism of E2 on VEGF. VEGF, ERα and β-catenin expression was increased in endometriotic lesions compared with normal endometrium. E2 could promote ERα, β-catenin and VEGF expression in ESCs. ChIP and luciferase assays revealed that E2 up-regulated β-catenin expression by binding to the estrogen response element site on the β-catenin promoter. β-Catenin stabilization could activate Wnt/β-catenin signaling, which has a direct transcriptional effect on VEGF gene expression. Endometriotic lesions were all from ovarian endometriosis and may differ from other type of endometriosis. These promising results improve the body of knowledge on endometriosis pathogenesis and could open up new therapeutic strategies for the treatment of endometriosis. This project was supported by the National Natural Science Foundation of China (grant no. 81170545 Y.L. and 81471439 Y.L.). None of the authors has any conflicting interests to declare.

Roles of Estrogen Receptor-α and the Coactivator MED1 During Human Endometrial Decidualization.

The steroid hormones 17β-estradiol and progesterone are critical regulators of endometrial stromal cell differentiation, known as decidualization, which is a prerequisite for successful establishment of pregnancy. The present study using primary human endometrial stromal cells (HESCs) addressed the role of estrogen receptor-α (ESR1) in decidualization. Knockdown of ESR1 transcripts by RNA interference led to a marked reduction in decidualization of HESCs. Gene expression profiling at an early stage of decidualization indicated that ESR1 negatively regulates several cell cycle regulatory factors, thereby suppressing the proliferation of HESCs as these cells enter the differentiation program. ESR1 also controls the expression of WNT4, FOXO1, and progesterone receptor (PGR), well-known mediators of decidualization. Whereas ESR1 knockdown strongly inhibited the expression of FOXO1 and WNT4 transcripts within 24 hours of the initiation of decidualization, PGR expression remained unaffected at this early time point. Our study also revealed a major role of cAMP signaling in influencing the function of ESR1 during decidualization. Using a proteomic approach, we discovered that the cAMP-dependent protein kinase A (PKA) phosphorylates Mediator 1 (MED1), a subunit of the mediator coactivator complex, during HESC differentiation. Using immunoprecipitation, we demonstrated that PKA-phosphorylated MED1 interacts with ESR1. The PKA-dependent phosphorylation of MED1 was also correlated with its enhanced recruitment to estrogen-responsive elements in the WNT4 gene. Knockdown of MED1 transcripts impaired the expression of ESR1-induced WNT4 and FOXO1 transcripts and blocked decidualization. Based on these findings, we conclude that modulation of ESR1-MED1 interactions by cAMP signaling plays a critical role in human decidualization.

Exosomes derived from endometriotic stromal cells have enhanced angiogenic effects in vitro.

Our objective has been to establish a pro-angiogenic role for exosomes in endometriosis and to determine whether a differential expression profile of cellular and exosomal microRNAs (miRNAs) exists in endometriosis. We performed an in vitro study of human primary endometrial stromal cells (ESCs) and human umbilical vein endothelial cells (HUVECs). We isolated and characterized exosomes from ESCs from five endometriosis patients and five phase-matched controls. Exosomes were characterized by transmission electron microscopy and NanoSight technology. MiRNA was assessed by deep sequencing and reverse transcription with quantitative polymerase chain reaction. Exosome uptake studies were achieved by means of confocal microscopy. The pro-angiogenic experiments were executed by treating HUVECs with ESC-derived exosomes. We observed differential profiles of exosomal miRNA expression between exosomes derived from endometriosis lesion cells and diseased eutopic stromal cells compared with exosomes derived from control ESCs. We also demonstrated autocrine cellular uptake of exosomes and paracrine functional angiogenic effects of exosomes on HUVECs. The results of this study support the hypothesis that exosomes derived from ESCs play autocrine/paracrine roles in the development of endometriosis, potentially modulating angiogenesis. The broader clinical implications are that Sampson’s theory of retrograde menstruation possibly encompasses the finding that exosomes work as intercellular communication modulators in endometriosis.Electronic supplementary materialThe online version of this article (doi:10.1007/s00441-016-2358-1) contains supplementary material, which is available to authorized users.

In silico, in vitro and in vivo analysis identifies a potential role for steroid hormone regulation of FOXD3 in endometriosis-associated genes.

Can bioinformatics analysis of publically available microarray datasets be utilized in identifying potentially important transcription factors (TF) in the hormonal regulation of the endometrium? Systems integration and analysis of existing complex (published) datasets, predicted a role for the novel transcription factor, Forkhead Box D3 (FOXD3) in healthy endometrium and in endometriosis, which was followed by the demonstration of decreased levels of the protein upon decidualisation of normal human endometrial stromal cells in vitro and differential endometrial expression in the stroma in endometriosis. The reported endometriosis-associated endometrial aberrations are most pronounced in the progesterone-dominant secretory phase and progesterone resistance is a proposed causative factor. The study was initially an 'in silico' study, with confirmatory 'wet lab' data from western blotting (WB), qPCR and Immunohistochemistry (IHC) on endometrial biopsies obtained from 142 women undergoing gynaecological surgery. The study was conducted at a University Research Institute. Bioinformatic analysis of selected published microarray datasets identified differentially regulated genes for the early and mid-secretory phases relative to the proliferative phase. Diseases and Functions categories were identified with Ingenuity (IPA) 'core analysis' software. The key transcription factors controlling secretory phase gene changes were revealed with oPOSSUM software. FOXD3 expression levels were examined in human endometrial samples from women aged 18-55 years by WB, IHC, and qPCR. The progesterone regulation of endometrial FOXD3 levels was examined in vivo and in cultured primary human endometrial stromal cells in vitro. Initial data mining and subsequent bioinformatics analysis of human endometrial microarray datasets identified FOXD3 to be a key regulator of gene expression specific to secretory phase/endometriosis. FOXD3 was dynamically expressed in healthy endometrium and differentially expressed in endometriosis. In vitro decidualisation of primary endometrial stromal cells significantly decreased FOXD3 protein (P = 0.0005) and progestagen (Levonorgestrel) treatment also reduced the high endometrial FOXD3 protein (P = 0.0001) and mRNA levels (P = 0.04) seen in untreated women with endometriosis, with a shift of FOXD3 from the nucleus to the cytoplasm. The quality of Bioinformatics analysis and results depends on the published micro-array data. An in depth analysis of FOXD3 function and its relationship with estrogen and progesterone might provide insights into its potential deregulation in proliferative disorders of the endometrium including endometrial cancer where its expression is also deregulated. Further, FOX transcription factors are increasingly seen as novel therapeutic targets in disease. We acknowledge the support by Wellbeing of Women project grant RG1073 (D.K.H., A.J.V.). We also acknowledge the support of Liverpool Women's Hospital Foundation Trust (J.A.D.), Institute of Translational Medicine (D.M., A.J.V., D.K.H.) and the Institute of Integrative Biology (O.V.), University of Liverpool. All authors declare no conflict of interest. N/A.

Apoptosis modulation by activin A and follistatin in human endometrial stromal cells

Activin A is a growth factor that stimulates decidualization and is abundantly expressed in endometrial proliferative disorders. Nevertheless, whether it directly affects endometrial cell survival is still unknown. This study investigated the effects of activin A on total death and apoptosis rates and on tumor necrosis factor (TNF) release by human endometrial stromal cells (HESC). We performed a controlled prospective in vitro study using primary HESC cultures obtained from healthy reproductive age women (n = 11). Cells were treated with medium alone (control) or activin A (25 ng/mL) or activin A (25 ng/mL) and its antagonist follistatin (250 ng/mL). Apoptosis and total cell death were measured by flow cytometry, while TNF concentrations in culture media were quantified by ELISA. Activin A decreased the percentage of apoptotic/dead cells from 31% to 22% (p < 0.05, paired t-test) and reduced TNF levels in culture medium by 14%, but there was no linear correlation between TNF release and apoptotic rates. Both effects of activin A were reversed by follistatin. These findings indicate that activin A promotes HESC survival, possibly by a TNF-independent pathway. This mechanism may be critical to the actions of activin A upon stromal cell growth and differentiation in physiology and disease.

Fibulin-5 is upregulated in decidualized human endometrial stromal cells and promotes primary human extravillous trophoblast outgrowth

Interactions between the highly invasive trophoblasts and the maternal uterine decidual extracellular matrix (ECM) are crucial in the determination of a successful pregnancy. Fibulin-5 (FBLN5) is a member of the fibulin family that alters cell adhesive and invasive properties and is expressed in human villous cytotrophoblasts.We aimed to determine the expression and immunolocalization of FBLN5 in human first trimester decidua and examine the effect of FBLN5 in trophoblast invasion in vitro using a first trimester placental villous outgrowth assay. We demonstrated that FBLN5 mRNA expression is upregulated in response to cAMP-mediated decidualization of primary human endometrial stromal cells, although FBLN5 itself does not enhance decidualization. We reported for the first time, FBLN5 protein production in first trimester decidual cells and also co-localization to HLAG-positive EVTs in first trimester decidua. Consequently, we investigated the effects of exogenous FBLN5 on placental villous outgrowth in vitro and demonstrated that FBLN5 promotes EVT migration/invasion. This is the first study to identify FBLN5 in decidualized human endometrial stromal cells, first trimester decidua and EVT and determine a functional role for FBLN5 in human EVTs, suggesting that decidual and or EVT-derived FBLN5 regulates EVT invasion and placentation in women.

Progesterone receptor transcriptome and cistrome in decidualized human endometrial stromal cells.

Decidualization is a complex process involving cellular proliferation and differentiation of the endometrial stroma that is required to establish and support pregnancy. Progesterone acting via its nuclear receptor, the progesterone receptor (PGR), is a critical regulator of decidualization and is known to interact with certain members of the activator protein-1 (AP-1) family in the regulation of transcription. In this study, we identified the cistrome and transcriptome of PGR and identified the AP-1 factors FOSL2 and JUN to be regulated by PGR and important in the decidualization process. Direct targets of PGR were identified by integrating gene expression data from RNA sequencing with the whole-genome binding profile of PGR determined by chromatin immunoprecipitation followed by deep sequencing (ChIP-seq) in primary human endometrial stromal cells exposed to 17β-estradiol, medroxyprogesterone acetate, and cAMP to promote in vitro decidualization. Ablation of FOSL2 and JUN attenuates the induction of 2 decidual marker genes, IGFBP1 and PRL. ChIP-seq analysis of genomic binding revealed that FOSL2 is bound in proximity to 8586 distinct genes, including nearly 80% of genes bound by PGR. A comprehensive assessment of the PGR-dependent decidual transcriptome integrated with the genomic binding of PGR identified FOSL2 as a potentially important transcriptional coregulator of PGR via direct interaction with regulatory regions of genes actively regulated during decidualization.

Diet-induced obesity impairs endometrial stromal cell decidualization

There is strong evidence that decreased pregnancy rates and higher miscarriage rates exist in obese women. Whether these effects are secondary to abnormal implantation, embryo development, or poor oocyte quality are unknown, although all of these factors may contribute. Our study objective was to investigate, via an in vivo and in vitro model, whether exposure of endometrial stromal cells (ESC) to saturated fatty acids or a high fat environment impairs decidualization. To test the effects of diet-induced obesity on ESC decidualization in vivo, artificial deciduomas were induced in high fat-fed versus chow-fed control mice. In vitro cell culture models were also used to determine the impact of saturated fatty acids on ESC differentiation. Artificial Deciduoma: Six-week old C57BL/6 female were fed either a high fat diet (59.4% Kcal from fat, HFD) or chow (CON) for twelve weeks. To induce decidualization in vivo, a silk thread was placed in the left uterine horn of pseudopregnant CON (n=5) and HFD (n=6) mice on dpc 3.5. Three days after thread placement, uterine horns were collected, and deciduoma formation was evaluated by comparing the uterine masses and morphologic changes via histology. In Vitro Decidualization: Human immortalized endometrial stromal cells (hESC-T) and human primary endometrial stromal cells were cultured in 1μM medroxyprogesterone-17-acetate and 0.5mM dibutyryladenosine cAMP for 9 days to induce decidualization. During this time, cells were also treated with either saturated fatty acids (100μM palmitic acid ) or vehicle (BSA). RNA was isolated and RT-qPCR was performed to analyze expression of decidual markers, IGFBP1 and PRL. HFD mice were significantly heavier, had 100% increase in fat mass, and were glucose intolerant. Furthermore, we observed a 36% decrease in deciduoma weights and impaired ESC differentiation via histological analysis in the HFD vs. CON mice. In vitro studies also revealed that hESC-T cells differentiated in the presence of saturated fatty acids had significantly lower gene expression of IGFBP-1 and PRL, indicating impaired decidualization. This observation was confirmed in human primary endometrial stromal cells. Taken together, these data indicate that a diet high in saturated fatty acids may impair uterine receptivity via altered ESC decidualization. Although the mechanism by which this occurs needs to be further investigated, our preliminary data suggests that poor decidualization may contribute to implantation defects in obesity.

Retinoic acid biosynthesis is impaired in human and murine endometriosis.

Endometriosis is characterized by the presence of endometrial glands and stroma in extrauterine sites. Our objective was to determine whether endometriotic lesions (ELs) from women with endometriosis have altered retinoid levels compared with their eutopic endometrium, and to test the hypothesis that defects in all-trans retinoic acid (ATRA) biosynthesis in EL is related to reduced expression of cellular retinol-binding protein type 1 (RBP1). Retinoids were evaluated by liquid chromatography-tandem mass spectrometry and high-performance liquid chromatography in eutopic endometrial biopsies (EBs) and ELs from 42 patients with pathologically confirmed endometriosis. The ATRA levels were reduced, whereas the retinol and retinyl ester concentrations were elevated in EL compared with EB tissue. Similar results were found in a mouse model of endometriosis that used green fluorescent protein-positive endometrial tissue injected into the peritoneum of syngeneic hosts to mimic retrograde menses. The ATRA biosynthesis in vitro in retinol-treated primary human endometrial stromal cell (ESC) cultures derived from ELs was reduced compared with that of ESCs derived from patient-matched EBs. Correspondingly, RBP1 expression was reduced in tissue and ESCs derived from EL versus EB. Rbp1(-/-) mice showed reduced endometrial ATRA concentrations compared with wild type, associated with loss of tissue organization and hypercellularity. These findings provide the first quantitative measurements of ATRA in human endometrium and endometriosis, demonstrating reduced ATRA in ectopic tissue and corresponding ESC cultures. Quantitation of retinoids in murine endometriosis and in Rbp1(-/-) mice supports the contention that impaired ATRA synthesis caused by reduced RBP1 promotes an "endometriosis phenotype" that enables cells to implant and grow at ectopic sites.

The epidermal growth factor receptor critically regulates endometrial function during early pregnancy.

Infertility and adverse gynecological outcomes such as preeclampsia and miscarriage represent significant female reproductive health concerns. The spatiotemporal expression of growth factors indicates that they play an important role in pregnancy. The goal of this study is to define the role of the ERBB family of growth factor receptors in endometrial function. Using conditional ablation in mice and siRNA in primary human endometrial stromal cells, we identified the epidermal growth factor receptor (Egfr) to be critical for endometrial function during early pregnancy. While ablation of Her2 or Erbb3 led to only a modest reduction in litter size, mice lacking Egfr expression are severely subfertile. Pregnancy demise occurred shortly after blastocyst implantation due to defects in decidualization including decreased proliferation, cell survival, differentiation and target gene expression. To place Egfr in a genetic regulatory hierarchy, transcriptome analyses was used to compare the gene signatures from mice with conditional ablation of Egfr, wingless-related MMTV integration site 4 (Wnt4) or boneless morphogenic protein 2 (Bmp2); revealing that not only are Bmp2 and Wnt4 key downstream effectors of Egfr, but they also regulate distinct physiological functions. In primary human endometrial stromal cells, marker gene expression, a novel high content image-based approach and phosphokinase array analysis were used to demonstrate that EGFR is a critical regulator of human decidualization. Furthermore, inhibition of EGFR signaling intermediaries WNK1 and AKT1S1, members identified in the kinase array and previously unreported to play a role in the endometrium, also attenuate decidualization. These results demonstrate that EGFR plays an integral role in establishing the cellular context necessary for successful pregnancy via the activation of intricate signaling and transcriptional networks, thereby providing valuable insight into potential therapeutic targets.

Two Methods for Establishing Primary Human Endometrial Stromal Cells from Hysterectomy Specimens

Two Methods for Establishing Primary Human Endometrial Stromal Cells from Hysterectomy Specimens

Two methods for establishing primary human endometrial stromal cells from hysterectomy specimens.

Many efforts have been devoted to establish in vitro cell culture systems. These systems are designed to model a vast number of in vivo processes. Cell culture systems arising from human endometrial samples are no exception. Applications range from normal cyclic physiological processes to endometrial pathologies such as gynecological cancers, infectious diseases, and reproductive deficiencies. Here, we provide two methods for establishing primary endometrial stromal cells from surgically resected endometrial hysterectomy specimens. The first method is referred to as "the scraping method" and incorporates mechanical scraping using surgical or razor blades whereas the second method is termed "the trypsin method." This latter method uses the enzymatic activity of trypsin to promote the separation of cells and primary cell outgrowth. We illustrate step-by-step methodology through digital images and microscopy. We also provide examples for validating endometrial stromal cell lines via quantitative real time polymerase chain reactions (qPCR) and immunofluorescence (IF).

A Murine Uterine Transcriptome, Responsive to Steroid Receptor Coactivator-2, Reveals Transcription Factor 23 as Essential for Decidualization of Human Endometrial Stromal Cells1

Recent data from human and mouse studies strongly support an indispensable role for steroid receptor coactivator-2 (SRC-2)-a member of the p160/SRC family of coregulators-in progesterone-dependent endometrial stromal cell decidualization, an essential cellular transformation process that regulates invasion of the developing embryo into the maternal compartment. To identify the key progesterone-induced transcriptional changes that are dependent on SRC-2 and required for endometrial decidualization, we performed comparative genome-wide transcriptional profiling of endometrial tissue RNA from ovariectomized SRC-2(flox/flox) (SRC-2(f/f) [control]) and PR(cre/+)/SRC-2(flox/flox) (SRC-2(d/d) [SRC-2-depleted]) mice, acutely treated with vehicle or progesterone. Although data mining revealed that only a small subset of the total progesterone-dependent transcriptional changes is dependent on SRC-2 (∼13%), key genes previously reported to mediate progesterone-driven endometrial stromal cell decidualization are present within this subset. Along with providing a more detailed molecular portrait of the decidual transcriptional program governed by SRC-2, the degree of functional diversity of these progesterone mediators underscores the pleiotropic regulatory role of SRC-2 in this tissue. To showcase the utility of this powerful informational resource to uncover novel signaling paradigms, we stratified the total SRC-2-dependent subset of progesterone-induced transcriptional changes in terms of novel gene expression and identified transcription factor 23 (Tcf23), a basic-helix-loop-helix transcription factor, as a new progesterone-induced target gene that requires SRC-2 for full induction. Importantly, using primary human endometrial stromal cells in culture, we demonstrate that TCF23 function is essential for progesterone-dependent decidualization, providing crucial translational support for this transcription factor as a new decidual mediator of progesterone action.

Androgens Modulate the Morphological Characteristics of Human Endometrial Stromal Cells Decidualized In Vitro

The activated androgen receptor (AR) in decidualizing human endometrial stromal cells (HESCs) regulates genes involved in cytoskeletal organization, cell motility, and cell cycle progression. Androgens also enhance the secretion of prolactin, a widely used marker of decidualized HESCs. The purpose of the present study was to investigate the direct effects of androgens on the ultrastructural changes associated with decidual transformation of HESCs. Primary HESC cultures were established and propagated, and confluent cultures were decidualized for 6 days with 8-bromoadenosine 3',5'-cyclic monophosphate (8-br-cAMP) and progesterone (P4) in the presence or absence of dihydrotestosterone (DHT). Phase-contrast image analysis demonstrated that DHT increases the shape index of decidualizing cells, which was reversed upon cotreatment with the AR antagonist flutamide. Electron microscopy demonstrated that DHT enhances many of the ultrastructural changes induced by 8-br-cAMP and P4 in HESCs. Decidualizing cells are characterized by an abundant cytoplasm, multiple cell surface projections and, unlike undifferentiated HESCs, form 2 or more cell layers. The DHT further stimulated cytoplasmic expansion, lipid droplet formation, the production of an abundant extracellular matrix, and gap junction formation in decidualized HESCs. The present study demonstrates that androgen signaling has an impact on the morphological and ultrastructural changes associated with the decidual process. Our findings show that androgens promote the development and expansion of cytoplasmic organelles and gap junctions in decidualizing HESCs. These results suggest that androgens in early pregnancy play an important role in promoting the cellular transformation associated with decidualization.

Estradiol-17β Upregulates Pyruvate Kinase M2 Expression to Coactivate Estrogen Receptor-α and to Integrate Metabolic Reprogramming With the Mitogenic Response in Endometrial Cells

Proliferating cells reprogram their cellular glucose metabolism to meet the bioenergetic and biosynthetic demands and to maintain cellular redox homeostasis. Pyruvate kinase M (PKM) is a critical regulator of this metabolic reprogramming. However, whether estradiol-17β (E2) reprograms cellular metabolism to support proliferation of human primary endometrial stromal cells (hESCs) and the molecular basis of this reprogramming are not well understood. Our objectives were to study whether E2 induces reprogramming of glucose metabolism in hESCs and to investigate the potential roles of PKM2 in E2-induced metabolic reprogramming and proliferation of these cells. The oxygen consumption rate and extracellular acidification rate were assessed by a Seahorse XF24 analyzer. PKM2 expression was assessed by real-time RT-PCR and immunoblotting. E2 induces a Warburg-like glucose metabolism in hESCs by inducing the expression of PKM. E2 also enhanced PKM splicing into the PKM2 isoform by upregulating the c-Myc-hnRNP axis. Furthermore, E2 induces PKM2 oxidation, phosphorylation, and nuclear translocation. In addition to its glycolytic function, PKM2 physically interacted with estrogen receptor-α (ERα) and functioned as an ERα coactivator. Small-molecule PKM2 activators ameliorated ERα transcriptional activity and abrogated the E2-induced hESC proliferation. We show for the first time that E2-induced hESC proliferation is associated with a shift in glucose metabolism toward aerobic glycolysis, and the molecular basis for this metabolic shift is linked to the effects of E2 on PKM2. In addition, PKM2 acts as a transcriptional coactivator for ERα and small-molecule PKM2 activators inhibit ERα transcriptional activity and reduce E2-induced cell proliferation.