Uterine epithelial cell proliferation and endometrial hyperplasia: evidence from a mouse model

Differential expression of ion channel coding genes in the endometrium of women experiencing recurrent implantation failures

Our study probed the differences in ion channel gene expression in the endometrium of women with Recurrent Implantation Failure (RIF) compared to fertile women. We analyzed the relative expression of genes coding for T-type Ca2+, ENaC, CFTR, and KCNQ1 channels in endometrial samples from 20 RIF-affected and 10 control women, aged 22-35, via microarray analysis and quantitative real-time PCR. Additionally, we examined DNA methylation in the regulatory region of KCNQ1 using ChIP real-time PCR. The bioinformatics component of our research included Gene Ontology analysis, protein-protein interaction networks, and signaling pathway mapping to identify key biological processes and pathways implicated in RIF. This led to the discovery of significant alterations in the expression of ion channel genes in RIF women's endometrium, most notably an overexpression of CFTR and reduced expression of SCNN1A, SCNN1B, SCNN1G, CACNA1H, and KCNQ1. A higher DNA methylation level of KCNQ1's regulatory region was also observed in RIF patients. Gene-set enrichment analysis highlighted a significant presence of genes involved with ion transport and membrane potential regulation, particularly in sodium and calcium channel complexes, which are vital for cation movement across cell membranes. Genes were also enriched in broader ion channel and transmembrane transporter complexes, underscoring their potential extensive role in cellular ion homeostasis and signaling. These findings suggest a potential involvement of ion channels in the pathology of implantation failure, offering new insights into the mechanisms behind RIF and possible therapeutic targets.

Inflammation accelerating intestinal fibrosis: from mechanism to clinic

Intestinal fibrosis is a prevalent complication of IBD that that can frequently be triggered by prolonged inflammation. Fibrosis in the gut can cause a number of issues, which continue as an ongoing challenge to healthcare systems worldwide. The primary causes of intestinal fibrosis are soluble molecules, G protein-coupled receptors, epithelial-to-mesenchymal or endothelial-to-mesenchymal transition, and the gut microbiota. Fresh perspectives coming from in vivo and in vitro experimental models demonstrate that fibrogenic pathways might be different, at least to some extent, independent of the ones that influence inflammation. Understanding the distinctive procedures of intestinal fibrogenesis should provide a realistic foundation for targeting and blocking specific fibrogenic pathways, estimating the risk of fibrotic consequences, detecting early fibrotic alterations, and eventually allowing therapy development. Here, we first summarize the inflammatory and non-inflammatory components of fibrosis, and then we elaborate on the underlying mechanism associated with multiple cytokines in fibrosis, providing the framework for future clinical practice. Following that, we discuss the relationship between modernization and disease, as well as the shortcomings of current studies. We outline fibrosis diagnosis and therapy, as well as our recommendations for the future treatment of intestinal fibrosis. We anticipate that the global review will provides a wealth of fresh knowledge and suggestions for future fibrosis clinical practice.

Role of EZH2 in Uterine Gland Development

Enhancer of zeste homolog 2 (EZH2) is a core component of polycomb repressive complex 2 that plays a vital role in transcriptional repression of gene expression. Conditional ablation of EZH2 using progesterone receptor (Pgr)-Cre in the mouse uterus has uncovered its roles in regulating uterine epithelial cell growth and stratification, suppressing decidual myofibroblast activation, and maintaining normal female fertility. However, it is unclear whether EZH2 plays a role in the development of uterine glands, which are required for pregnancy success. Herein, we created mice with conditional deletion of Ezh2 using anti-Mullerian hormone receptor type 2 (Amhr2)-Cre recombinase that is expressed in mesenchyme-derived cells of the female reproductive tract. Strikingly, these mice showed marked defects in uterine adenogenesis. Unlike Ezh2 Pgr-Cre conditional knockout mice, deletion of Ezh2 using Amhr2-Cre did not lead to the differentiation of basal-like cells in the uterus. The deficient uterine adenogenesis was accompanied by impaired uterine function and pregnancy loss. Transcriptomic profiling using next generation sequencing revealed dysregulation of genes associated with signaling pathways that play fundamental roles in development and disease. In summary, this study has identified an unrecognized role of EZH2 in uterine gland development, a postnatal event critical for pregnancy success and female fertility.

Characterization of Adrenal miRNA-Based Dysregulations in Cushing's Syndrome

MiRNAs are important epigenetic players with tissue- and disease-specific effects. In this study, our aim was to investigate the putative differential expression of miRNAs in adrenal tissues from different forms of Cushing’s syndrome (CS). For this, miRNA-based next-generation sequencing was performed in adrenal tissues taken from patients with ACTH-independent cortisol-producing adrenocortical adenomas (CPA), from patients with ACTH-dependent pituitary Cushing’s disease (CD) after bilateral adrenalectomy, and from control subjects. A confirmatory QPCR was also performed in adrenals from patients with other CS subtypes, such as primary bilateral macronodular hyperplasia and ectopic CS. Sequencing revealed significant differences in the miRNA profiles of CD and CPA. QPCR revealed the upregulated expression of miR-1247-5p in CPA and PBMAH (log2 fold change > 2.5, p < 0.05). MiR-379-5p was found to be upregulated in PBMAH and CD (log2 fold change > 1.8, p < 0.05). Analyses of miR-1247-5p and miR-379-5p expression in the adrenals of mice which had been exposed to short-term ACTH stimulation showed no influence on the adrenal miRNA expression profiles. For miRNA-specific target prediction, RNA-seq data from the adrenals of CPA, PBMAH, and control samples were analyzed with different bioinformatic platforms. The analyses revealed that both miR-1247-5p and miR-379-5p target specific genes in the WNT signaling pathway. In conclusion, this study identified distinct adrenal miRNAs as being associated with CS subtypes.

Piceatannol SNEDDS Attenuates Estradiol-Induced Endometrial Hyperplasia in Rats by Modulation of NF-κB and Nrf2/HO-1 Axes

Endometrial hyperplasia (EH) is the most common risk factor for endometrial malignancy in females. The pathogenesis of EH has been directly linked to uterine inflammation, which can result in abnormal cell division and decreased apoptosis. Piceatannol (PIC), a natural polyphenolic stilbene, is known to exert anti-inflammatory, antioxidant and anti-proliferative activities. The aim of the present study was to examine the potential preventive role of PIC in estradiol benzoate (EB)-induced EH in rats. A self-nanoemulsifying drug delivery system (SNEDDS) was prepared to improve the solubility of the PIC. Therefore, thirty female Wistar rats were divided into five groups: (1) control, (2) PIC SNEDDS (10 mg/kg), (3) EB (0.6 mg/kg), (4) EB + PIC SNEDDS (5 mg/kg) and (5) EB + PIC SNEDDS (10 mg/kg). The administration of PIC SNEDDS prevented EB-induced increases in uterine weights and histopathological changes. Additionally, it displayed pro-apoptotic and antioxidant activity in the endometrium. Immunohistochemical staining of uterine sections co-treated with PIC SNEDDS showed significantly decreased expression of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and nuclear transcription factor-kappa B (NF-κB). This anti-inflammatory effect was further confirmed by a significant increase in Nrf2 and heme oxygenase-1 (HO-1) expression. These results indicate that SNEDDS nanoformulation of PIC possesses protective effects against experimentally induced EH.

Endometrial PTEN Deficiency Leads to SMAD2/3 Nuclear Translocation

Simple Summary

PTEN is a protein highly altered in endometrial cancer. PTEN mutation or deficiency leads to the activation of other downstream proteins that are important to the development of cancers. In this study, we have identified the SMAD2/3 proteins as targets of PTEN deficiency. We have found that loss of PTEN in endometrial cells leads to SMAD2/3 activation. To investigate the role of SMAD2/3 activation downstream of PTEN deficiency, we have used endometrial cells lacking both PTEN and SMAD2/3 proteins. These cells display even more tumorigenic potential than cells lacking only PTEN. These results suggest that SMAD2/3 acts as an obstacle for cancer development triggered by PTEN loss.

Abstract

TGF-β has a dichotomous function, acting as tumor suppressor in premalignant cells but as a tumor promoter for cancerous cells. These contradictory functions of TGF-β are caused by different cellular contexts, including both intracellular and environmental determinants. The TGF-β/SMAD and the PI3K/PTEN/AKT signal transduction pathways have an important role in the regulation of epithelial cell homeostasis and perturbations in either of these two pathways’ contributions to endometrial carcinogenesis. We have previously demonstrated that both PTEN and SMAD2/3 display tumor-suppressive functions in the endometrium, and genetic ablation of either gene results in sustained activation of PI3K/AKT signaling that suppresses TGF-β-induced apoptosis and enhances cell proliferation of mouse endometrial cells. However, the molecular and cellular effects of PTEN deficiency on TGF-β/SMAD2/3 signaling remain controversial. Here, using an in vitro and in vivo model of endometrial carcinogenesis, we have demonstrated that loss of PTEN leads to a constitutive SMAD2/3 nuclear translocation. To ascertain the function of nuclear SMAD2/3 downstream of PTEN deficiency, we analyzed the effects of double deletion PTEN and SMAD2/3 in mouse endometrial organoids. Double PTEN/SMAD2/3 ablation results in a further increase of cell proliferation and enlarged endometrial organoids compared to those harboring single PTEN, suggesting that nuclear translocation of SMAD2/3 constrains tumorigenesis induced by PTEN deficiency.

SPP1 expression in the mouse uterus and placenta: Implications for implantation

Secreted phosphoprotein 1 [SPP1, also known as osteopontin (OPN)] binds integrins to mediate cell-cell and cell-extracellular matrix communication to promote cell adhesion, migration, and differentiation. Considerable evidence links SPP1 to pregnancy in several species. Current evidence suggests that SPP1 is involved in implantation and placentation in mice, but in vivo localization of SPP1 and in vivo mechanistic studies to substantiate these roles are incomplete and contradictory. We localized Spp1 mRNA and protein in the endometrium and placenta of mice throughout gestation, and utilized delayed implantation of mouse blastocysts to link SPP1 expression to the implantation chamber. Spp1 mRNA and protein localized to the endometrial luminal (LE), but not glandular epithelia (GE) in interimplantation regions of the uterus throughout gestation. Spp1 mRNA and protein also localized to uterine naturel killer (uNK) cells of the decidua. Within the implantation chamber, Spp1 mRNA localized only to intermittent LE cells, and to the inner cell mass. SPP1 protein localized to intermittent trophoblast cells, and to the parietal endoderm. These results suggest that SPP1: 1) is secreted by the LE at interimplantation sites for closure of the uterine lumen to form the implantation chamber; 2) is secreted by LE adjacent to the attaching trophoblast cells for attachment and invasion of the blastocyst; and 3) is not a component of histotroph secreted from the GE, but is secreted from uNK cells in the decidua to increase angiogenesis within the decidua to augment hemotrophic support of embryonic/fetal development of the conceptus.

Expression of Transforming Growth Factor Beta Isoforms in Canine Endometrium with Cystic Endometrial Hyperplasia-Pyometra Complex

Simple Summary

Pathomorphological changes and functional disorders of the uterus have long been a significant problem in the reproduction of dogs. The most commonly identified uterine disorders leading to permanent loss of fertility in dogs include cystic endometrial hyperplasia (CEH) and pyometra. These diseases may occur jointly as a CEH–pyometra complex. Despite numerous studies, the etiology of this disease remains unclear. TGF-β is considered to be one of the key factors in pathophysiological uterine disorders. The results indicate the significant expression of TGF-β1 in endometrial tissues in bitches affected by CEH–pyometra complex. Consequently, among all TGF-β isoforms, TGF-β1 is a potential biomarker involved in the regulation of a dog’s endometrium with proliferative and degenerative changes.

Abstract

Cystic endometrial hyperplasia (CEH) and pyometra are the most frequently diagnosed uterine diseases affecting bitches of different ages. Transforming growth factor beta (TGF-β) has been classified in females as a potential regulator of many endometrial changes during the estrous cycle or may be involved in pathological disorders. The aim of this study was to determine the expression of TGF-β1, -β2 and -β3 in the endometrium of bitches suffering from CEH or a CEH–pyometra complex compared to clinically healthy females (control group; CG). A significantly increased level of TGF-β1 mRNA expression was observed in the endometrium with CEH–pyometra compared to CEH and CG. Protein production of TGF-β1 was identified only in the endometrium of bitches with CEH–pyometra. An increase in TGF-β3 mRNA expression was observed in all the studied groups compared to CG. The expression of TGF-β2 mRNA was significantly higher in CEH and lower in CEH–pyometra uteri. The results indicate the presence of TGF-β cytokines in canine endometrial tissues affected by proliferative and degenerative changes. However, among all TGF-β isoforms, TGF-β1 could potentially be a key factor involved in the regulation of the endometrium in bitches with CEH–pyometra complex.

Functional similarity between TGF-beta type 2 and type 1 receptors in the female reproductive tract

Transforming growth factor β (TGFβ) signaling plays critical roles in reproductive development and function. TGFβ ligands signal through the TGFβ receptor type 2 (TGFBR2)/TGFBR1 complex. As TGFBR2 and TGFBR1 form a signaling complex upon ligand stimulation, they are expected to be equally important for propagating TGFβ signaling that elicits cellular responses. However, several genetic studies challenge this concept and indicate that disruption of TGFBR2 or TGFBR1 may lead to contrasting phenotypic outcomes. We have shown that conditional deletion of Tgfbr1 using anti-Mullerian hormone receptor type 2 (Amhr2)-Cre causes oviductal and myometrial defects. To determine the functional requirement of TGFBR2 in the female reproductive tract and the potential phenotypic divergence/similarity resulting from conditional ablation of either receptor, we generated mice harboring Tgfbr2 deletion using the same Cre driver that was previously employed to target Tgfbr1. Herein, we found that conditional deletion of Tgfbr2 led to a similar phenotype to that of Tgfbr1 deletion in the female reproductive tract. Furthermore, genetic removal of Tgfbr1 in the Tgfbr2-deleted uterus had minimal impact on the phenotype of Tgfbr2 conditional knockout mice. In summary, our results reveal the functional similarity between TGFBR2 and TGFBR1 in maintaining the structural integrity of the female reproductive tract.

Phenotype and biological characteristics of endometrial mesenchymal stem/stromal cells: A comparison between intrauterine adhesion patients and healthy women

PROBLEM

Intrauterine adhesion (IUA) is a uterine disorder with partial or total obstruction of the uterine cavity and/or the cervical canal primarily caused by intrauterine operations and infections. It is the most common cause of uterine infertility and recurrent abortion. However, the reasons for endometrium repair disorders in patients with IUA are still unclear. While increasing evidence demonstrates that endometrial mesenchymal stem/stromal cells (EMSCs) contribute to the regeneration and repair of endometrium, the roles of EMSCs in the pathogenesis of IUA have not been reported.

METHODS AND STUDY

We investigated the differences of phenotype and biological characteristics between EMSCs from women with IUA and healthy women. Firstly, the fibrosis of endometrium were measured by immunohistochemistry and Masson staining. Second, we used immunofluorescence to detect the location of EMSCs in endometrial tissue, and the proportion of CD146⁺ CD140b⁺ in the two groups was compared by flow cytometry. Then, plate colony formation experiment, CCK-8 assay, flow cytometry, would-healing assay, and transwell invasion experiment were used to compare the cloning ability, proliferation, cell cycle, migration and invasion capabilities respectively. Finally, we compared the potential angiogenesis and immunosuppression capabilities.

RESULTS

Our results showed that there were fewer CD146⁺ CD140b⁺ cells in patients with IUA, and the clone-forming, migration, invasion, angiogenic and immunosuppressive abilities of the EMSCs of patients with IUA were significantly decreased compared with those of healthy women.

CONCLUSION

There are some differences between the EMSCs of IUA patients and healthy women, which may be related to the occurrence of IUA and dysfunction of endometrium.

Transforming growth factor beta signaling and decidual integrity in mice†

Transforming growth factor beta (TGFβ) signaling regulates multifaceted reproductive processes. It has been shown that the type 1 receptor of TGFβ (TGFBR1) is indispensable for female reproductive tract development, implantation, placental development, and fertility. However, the role of TGFβ signaling in decidual development and function remains poorly defined. Our objective is to determine the impact of uterine-specific deletion of Tgfbr1 on decidual integrity, with a focus on the cellular and molecular properties of the decidua during development. Our results show that the developmental dynamics of the decidua is altered in TGFBR1 conditionally depleted uteri from embryonic day (E) 5.5 to E8.5, substantiated by downregulation of genes associated with inflammatory responses and uterine natural killer cell abundance, reduced presence of nondecidualized fibroblasts in the antimesometrial region, and altered decidual cell development. Notably, conditional ablation of TGFBR1 results in the formation of decidua containing more abundant alpha smooth muscle actin (ACTA2)-positive cells at the peripheral region of the antimesometrial side versus controls at E6.5-E8.5. This finding is corroborated by upregulation of a subset of smooth muscle marker genes in Tgfbr1 conditionally deleted decidua at E6.5 and E8.5. Moreover, increased cell proliferation and enhanced decidual ERK1/2 signaling were found in Tgfbr1 conditional knockout mice upon decidual regression. In summary, conditional ablation of TGFBR1 in the uterus profoundly impacts the cellular and molecular properties of the decidua. Our results suggest that TGFBR1 in uterine epithelial and stromal compartments is important for the integrity of the decidua, a transient but crucial structure that supports embryo development.

The histone methyltransferase EZH2 is required for normal uterine development and function in mice†

Enhancer of zeste homolog 2 (EZH2) is a rate-limiting catalytic subunit of a histone methyltransferase, polycomb repressive complex, which silences gene activity through the repressive histone mark H3K27me3. EZH2 is critical for epigenetic effects of early estrogen treatment, and may be involved in uterine development and pathologies. We investigated EZH2 expression, regulation, and its role in uterine development/function. Uterine epithelial EZH2 expression was associated with proliferation and was high neonatally then declined by weaning. Pre-weaning uterine EZH2 expression was comparable in wild-type and estrogen receptor 1 knockout mice, showing neonatal EZH2 expression is ESR1 independent. Epithelial EZH2 was upregulated by 17β-estradiol (E2) and inhibited by progesterone in adult uteri from ovariectomized mice. To investigate the uterine role of EZH2, we developed a EZH2 conditional knockout (Ezh2cKO) mouse using a cre recombinase driven by the progesterone receptor (Pgr) promoter that produced Ezh2cKO mice lacking EZH2 in Pgr-expressing tissues (e.g. uterus, mammary glands). In Ezh2cKO uteri, EZH2 was deleted neonatally. These uteri had reduced H3K27me3, were larger than WT, and showed adult cystic endometrial hyperplasia. Ovary-independent uterine epithelial proliferation and increased numbers of highly proliferative uterine glands were seen in adult Ezh2cKO mice. Female Ezh2cKO mice were initially subfertile, and then became infertile by 9 months. Mammary gland development in Ezh2cKO mice was inhibited. In summary, uterine EZH2 expression is developmentally and hormonally regulated, and its loss causes aberrant uterine epithelial proliferation, uterine hypertrophy, and cystic endometrial hyperplasia, indicating a critical role in uterine development and function.

Molecular characterization of Wdr13 knockout female mice uteri: a model for human endometrial hyperplasia

Endometrial hyperplasia (EH) is a condition where uterine endometrial glands show excessive proliferation of epithelial cells that may subsequently progress into endometrial cancer (EC). Modern lifestyle disorders such as obesity, hormonal changes and hyperinsulinemia are known risk factors for EH. A mouse strain that mimics most of these risk factors would be an ideal model to study the stage-wise progression of EH disease and develop suitable treatment strategies. Wdr13, an X-linked gene, is evolutionarily conserved and expressed in several tissues including uteri. In the present study, Wdr13 knockout female mice developed benign proliferative epithelium that progressed into EH at around one year of age accompanied by an increase in body weight and elevated estradiol levels. Molecular characterization studies revealed increase in ERα, PI3K and a decrease in PAX2 and ERβ proteins in Wdr13 mutant mice uteri. Further, a decrease in the mRNA levels of cell cycle inhibitors, namely; p21 and cyclin G2 was seen. Leukocyte infiltration was observed in the uterine tissue of knockout mice at around 12 months of age. These physiological, molecular and pathological patterns were similar to those routinely seen in human EH disease and demonstrated the importance of WDR13 in mice uterine tissue. Thus, the genetic loss of Wdr13 in these mice led to mimicking of the human EH associated metabolic disorders making Wdr13 knockout female mice a potential animal model to study human endometrial hyperplasia.

The Roles of the Histone Protein Modifier EZH2 in the Uterus and Placenta

Epigenetic modifications regulate normal physiological, as well as pathological processes in various organs, including the uterus and placenta. Both organs undergo dramatic and rapid restructuring that depends upon precise orchestration of events. Epigenetic changes that alter transcription and translation of gene-sets regulate such responses. Histone modifications alter the chromatin structure, thereby affecting transcription factor access to gene promoter regions. Binding of histones to DNA is regulated by addition or removal of subunit methyl and other groups, which can inhibit or stimulate transcription. Enhancer of zeste homolog 2 (EZH2) is the catalytic subunit of polycomb repressive complex 2 (PRC2) that catalyzes tri-methylation of histone H3 at Lys 27 (H3K27me3) and subsequently suppresses transcription of genes bound by such histones. Uterine EZH2 expression exerts a critical role in development and function of this organ with deletion of this gene resulting in uterine hyperplasia and expression of cancer-associated transcripts. Elucidating the roles of EZH2 in uterus and placenta is essential as EZH2 dysregulation is associated with several uterine and placental pathologies. Herein, we discuss EZH2 functions in uterus and placenta, emphasizing its physiological and pathological importance.

Mice lacking uterine enhancer of zeste homolog 2 have transcriptomic changes associated with uterine epithelial proliferation

Enhancer of zeste homolog 2 (EZH2) is a histone methyltransferase that suppresses gene expression. Previously, we developed a conditional null model where EZH2 is knocked out in uterus. Deletion of uterine EZH2 increased proliferation of luminal and glandular epithelial cells. Herein, we used RNA-Seq in wild-type (WT) and EZH2 conditional knockout (Ezh2cKO) uteri to obtain mechanistic insights into the gene expression changes that underpin the pathogenesis observed in these mice. Ovariectomized adult Ezh2cKO mice were treated with vehicle (V) or 17β-estradiol (E2; 1 ng/g). Uteri were collected at postnatal day (PND) 75 for RNA-Seq or immunostaining for epithelial proliferation. Weighted gene coexpression network analysis was used to link uterine gene expression patterns and epithelial proliferation. In V-treated mice, 88 transcripts were differentially expressed (DEG) in Ezh2cKO mice, and Bmp5, Crabp2, Lgr5, and Sprr2f were upregulated. E2 treatment resulted in 40 DEG with Krt5, Krt15, Olig3, Crabp1, and Serpinb7 upregulated in Ezh2cKO compared with control mice. Transcript analysis relative to proliferation rates revealed two module eigengenes correlated with epithelial proliferation in WT V vs. Ezh2cKO V and WT E2 vs. Ezh2cKO E2 mice, with a positive relationship in the former and inverse in the latter. Notably, the ESR1, Wnt, and Hippo signaling pathways were among those functionally enriched in Ezh2cKO females. Current results reveal unique gene expression patterns in Ezh2cKO uterus and provide insight into how loss of this critical epigenetic regulator assumingly contributes to uterine abnormalities.

Prenatally androgenized female rats develop uterine hyperplasia when adult

Prenatal hyperandrogenization (PH) is hypothesized as one of the main factors contributing to the development of polycystic ovary syndrome (PCOS). In this study, we aimed to investigate the impact of prenatal exposure to androgen excess on the uterus when animals reach their adulthood. We found that PH altered the morphology of the uteri that show a hyperplastic morphology with increased total uterine thickness as well as luminal epithelium thickness, with both enhanced and altered distribution of glands as compared with controls. Morphological alterations were associated with an unbalanced homeostasis as assessed by the expression of regulators of cell cycle progression and cell death dynamics. PH also causes disturbances in the cell cycle of the uterine tissue and dysregulates cell death and survival pathways leading to the development of uterine hyperplasia. These findings suggest that PH may have a deleterious effect on the uterus.

Metformin alleviates endometrial hyperplasia through the UCA1/miR‑144/TGF‑β1/AKT signaling pathway

The objective of the present study was to investigate the molecular mechanism underlying the role of metformin (Met) in reducing the risk of endometrial hyperplasia (EH). Reverse transcription‑quantitative polymerase chain reaction, western blot and immunohistochemistry (IHC) assays were used to study the effects of Met and tamoxifen on the expression levels of urothelial cancer associated 1 (UCA1), microRNA‑144 (miR‑144) and other factors along the transforming growth factor‑β1 (TGF‑β1)/protein kinase B (AKT) signaling pathway. In addition, MTT and flow cytometry assays were performed to detect the effect of Met on cell proliferation and apoptosis. Tamoxifen treatment increased the weight of the uterus and the level of UCA1, while decreasing the expression of miR‑144. In addition, treatment with tamoxifen (2.0 and 3.5 µg) upregulated the protein expression levels of TGF‑β and p‑AKT, while downregulating the protein expression of active Caspase‑3 in a dose‑dependent manner. By contrast, Met reduced cell viability, promoted cell apoptosis, and reduced the expression levels of UCA1, TGF‑β and p‑AKT, while upregulating the expression of miR‑144 and active Caspase‑3 in a dose‑dependent manner. Furthermore, Met also reduced the weight of uterus. However, tamoxifen and Met did not exert any effect on the protein levels of total AKT and total Caspase‑3. The levels of TGF‑β and p‑AKT proteins in the EH group were much higher when compared with those in the sham group, while Met treatment reduced these protein levels to a certain extent. In addition, the expression of active Caspase‑3 in the EH group was much lower than that in the sham group, while Met treatment increased its level to a certain extent. In conclusion, the current study suggested that Met reduces the risk of EH by reducing the expression levels of UCA1, TGF‑β and p‑AKT, while increasing the levels of miR‑144 and active Caspase‑3 in a dose‑dependent manner.

Amelioration of estrogen-induced endometrial hyperplasia in female rats by hemin via heme-oxygenase-1 expression, suppression of iNOS, p38 MAPK, and Ki67

Although heme oxygenase-1 (HO-1) is part of an endogenous defense system implicated in the homeostatic response, its role in cell proliferation and tumor progression is still controversial. Endometrial hyperplasia (EH) is associated with high risk of endometrial cancer (EC). Therefore, we aimed to evaluate the effect of hemin, a HO-1 inducer, against EH. Thirty-two female rats (60-70 days old) were divided into 4 groups treated for 1 week: vehicle control group, hemin group (25 mg/kg; i.p. 3 times/week), estradiol valerate (EV) group (2 mg/kg per day, p.o.), and hemin plus EV group. Sera were obtained for reduced glutathione level. Uterine malondialdehyde, superoxide dismutase, total nitrite/nitrate, and interleukin-1β levels were estimated. HO-1 and p38 mitogen-activated protein kinase expressions were obtained in uterine tissue. Uterine histological and immunohistochemical assessment of iNOS and Ki67 were also done. Results demonstrated that upregulation of HO-1 expression in hemin plus EV rats led to amelioration of EH which was confirmed with histological examination. This was associated with significant decrease in oxidative stress parameters, p38 mitogen-activated protein kinase expression, and interleukin-1β level. Also, uterine iNOS and Ki67 expressions were markedly suppressed. In conclusion, upregulation of HO-1 expression via hemin has ameliorative effect against EH through its antioxidant, anti-inflammatory, and antiproliferative actions.

Effects of Benzo(a)pyrene on the endometrial receptivity and embryo implantation in mice: An experimental study

Background

Benzo(a)pyrene (BaP) as an environmental pollutant is ubiquitous in the environment and it has destructive effects on human health. So far, various studies have demonstrated that BaP can cause adverse effects on the female reproductive system, but the existing information is limited about the effects of BaP on the endometrial receptivity and embryo implantation.

Objective

The aim of this study was to investigate the effects of BaP on the endometrial receptivity and implantation in mice.

Materials and Methods

In this experimental study, 40 pregnant BALB/c mice were divided into 5 groups (n = 8/each) as follows: experimental groups received the doses of 100 µg/kg, 200 µg/kg, and 500 µg/kg BaP dissolved in corn oil, the control group received normal saline and sham group received corn oil. Pregnant mice administered these solutions from Day 1 to Day 5 of gestation by gavage. On Day 6, the mice were sacrificed. Then their embryos were counted and the hormonal, histomorphological and molecular analyses were performed on the mocusa of uterine tube.

Results

The data revealed that BaP reduces estrogen and progesterone levels, decreases the number of implantation site, endometrium thickness, uterine lumen diameter, stromal cells and endometrial glands, and blood vessels in the endometrium. However, the expression of Activin receptor-like kinase 5 and E-cadherin genes was not changed by BaP with different doses.

Conclusion

The finding of this study showed that BaP can change estrogen and progesterone levels, and endometrial morphology leads to impairing the endometrial receptivity and decreasing the number of implantation site.

Enhancer of Zeste 2 Polycomb Repressive Complex 2 Subunit Is Required for Uterine Epithelial Integrity

Normal proliferation and differentiation of uterine epithelial cells are critical for uterine development and function. Enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2), a core component of polycomb repressive complexes 2, possesses histone methyltransferase activity that catalyzes the trimethylation of lysine 27 of histone H3. EZH2 has been involved in epithelial-mesenchymal transition, a key event in development and carcinogenesis. However, its role in uterine epithelial cell function remains unknown. To determine the role of uterine EZH2, Ezh2 was conditionally deleted using progesterone receptor Cre recombinase, which is expressed in both epithelial and mesenchymal compartments of the uterus. Loss of EZH2 promoted stratification of uterine epithelium, an uncommon and detrimental event in the uterus. The abnormal epithelium expressed basal cell markers, including tumor protein 63, cytokeratin 5 (KRT5), KRT6A, and KRT14. These results suggest that EZH2 serves as a guardian of uterine epithelial integrity, partially via inhibiting the differentiation of basal-like cells and preventing epithelial stratification. The observed epithelial abnormality was accompanied by fertility defects, altered uterine growth and function, and the development of endometrial hyperplasia. Thus, the Ezh2 conditional knockout mouse model may be useful to explore mechanisms that regulate endometrial homeostasis and uterine function.

Crosstalk between SOX2 and cytokine signaling in endometrial carcinoma

Endometrial carcinoma is a cancer derived from oncogenesis of the regenerating uterine cavity, in which cytokine stimulation shapes cell differentiation and tissue remodeling. Expression of the stem cell factors SOX2, OCT4, NANOG, and MYC has been linked to tumor malignancy in several cancers. However, how these stem cell factors crosstalk with cytokine signaling to promote malignancy in endometrial carcinoma is still elusive. Here we report that the expression of SOX2 and MYC, but not that of OCT4 and NANOG, correlate with poor histological differentiation and prognosis, while SOX2 expression is negatively associated with MYC level. We found that SOX2-high endometrial carcinoma cells possessed a higher colony-forming ability than their SOX2-low counterparts, and knockdown of SOX2 attenuated the colony-forming ability. We observed that SOX2 regulated EGFR expression in a SOX2–EGFR positive feedback loop. EGF stimulation induced SOX2 expression and promoted migration of endometrial carcinoma cells, whereas TGF-β stimulation inhibited SOX2 expression and attenuated the colony-forming ability. Immunohistochemistry analysis revealed that SOX2 expression correlated with lymph node infiltration of endometrial carcinoma. Our findings support that cytokine-induced stem cell factor SOX2 possesses oncogenic properties, with the potential to serve as a prognostic biomarker in endometrial carcinoma.

Human Pluripotent Stem Cell Culture: Current Status, Challenges, and Advancement

Over the past two decades, human embryonic stem cells (hESCs) have gained attention due to their pluripotent and proliferative ability which enables production of almost all cell types in the human body in vitro and makes them an excellent tool to study human embryogenesis and disease, as well as for drug discovery and cell transplantation therapies. Discovery of human-induced pluripotent stem cells (hiPSCs) further expanded therapeutic applications of human pluripotent stem cells (PSCs). hPSCs provide a stable and unlimited original cell source for producing suitable cells and tissues for downstream applications. Therefore, engineering the environment in which these cells are grown, for stable and quality-controlled hPSC maintenance and production, is one of the key factors governing the success of these applications. hPSCs are maintained in a particular niche using specific cell culture components. Ideally, the culture should be free of xenobiotic components to render hPSCs suitable for therapeutic applications. Substantial efforts have been put to identify effective components, and develop culture conditions and protocols, for their large-scale expansion without compromising on quality. In this review, we discuss different media, their components and functions, including specific requirements to maintain the pluripotent and proliferative ability of hPSCs. Understanding the role of culture components would enable the development of appropriate conditions to promote large-scale, quality-controlled expansion of hPSCs thereby increasing their potential applications.

The uterine epithelial loss of Pten is inefficient to induce endometrial cancer with intact stromal Pten

Mutation of the tumor suppressor Pten often leads to tumorigenesis in various organs including the uterus. We previously showed that Pten deletion in the mouse uterus using a Pgr-Cre driver (Ptenf/fPgrCre/+) results in rapid development of endometrial carcinoma (EMC) with full penetration. We also reported that Pten deletion in the stroma and myometrium using Amhr2-Cre failed to initiate EMC. Since the Ptenf/fPgrCre/+ uterine epithelium was primarily affected by tumorigenesis despite its loss in both the epithelium and stroma, we wanted to know if Pten deletion in epithelia alone will induce tumorigenesis. We found that mice with uterine epithelial loss of Pten under a Ltf-iCre driver (Ptenf/f/LtfCre/+) develop uterine complex atypical hyperplasia (CAH), but rarely EMC even at 6 months of age. We observed that Ptenf/fPgrCre/+ uteri exhibit a unique population of cytokeratin 5 (CK5) and transformation related protein 63 (p63)-positive epithelial cells; these cells mark stratified epithelia and squamous differentiation. In contrast, Ptenf/fLtfCre/+ hyperplastic epithelia do not undergo stratification, but extensive epithelial cell apoptosis. This increased apoptosis is associated with elevation of TGFβ levels and activation of downstream effectors, SMAD2/3 in the uterine stroma. Our results suggest that stromal PTEN via TGFβ signaling restrains epithelial cell transformation from hyperplasia to carcinoma. In conclusion, this study, using tissue-specific deletion of Pten, highlights the epithelial-mesenchymal cross-talk in the genesis of endometrial carcinoma.

Mechanisms underlying the protective effect of montelukast in prevention of endometrial hyperplasia in female rats

OBJECTIVE

To study the possible protective role of montelukast in endometrial hyperplesia (EH) rat model, induced by estradiol valerate (EV).

METHODS/MATERIALS

Thirty six female albino Wistar rats were classified into 7 groups: normal control, EV (2 mg/kg/day, p.o.), montelukast (10 mg/kg/day, p.o.), montelukast (1 mg/kg/day, p.o.) + EV (2 mg/kg/day, p.o.), montelukast (10 mg/kg/day, p.o.) + EV (2 mg/kg/day, p.o.), montelukast (20 mg/kg/day, p.o.) + EV (2 mg/kg/day, p.o.) groups. Uterine malondialdehyde (MDA), superoxide dismutase (SOD), total nitrites (NO) and serum total antioxidant capacity (TAC) were determined. Uterine, serum total cholesterol, high density lipoprotein (HDL) and tumor necrosis factor (TNF)-α were measured. Histopathological examination of the uterine tissue was also done. In addition, immunohistochemistry was done using Phosphatase and tensin homolog (PTEN) and inducible nitric oxide synthase (iNOS) antibodies.

RESULTS

Our results showed that montelukast in dose dependant manner improves oxidative stress, lipids profile and TNF α which were affected by EV. Moreover, immunohistochemical examination revealed that montelukast markedly reduced iNOS expression, while expression of PTEN was markedly enhanced, as compared to EV group. The protective effects of montelukast were also verified histopathologically.

CONCLUSIONS

Montelukast in dose dependant manner provided biochemical and histo-pathological improvement in EV induced EH, through its anti-inflammatory, antioxidant activity and inhibition of iNOS expression with induction of PTEN expression.

TGFβ superfamily signaling and uterine decidualization

Decidualization is an intricate biological process where extensive morphological, functional, and genetic changes take place in endometrial stromal cells to support the development of an implanting blastocyst. Deficiencies in decidualization are associated with pregnancy complications and reproductive diseases. Decidualization is coordinately regulated by steroid hormones, growth factors, and molecular and epigenetic mechanisms. Transforming growth factor β (TGFβ) superfamily signaling regulates multifaceted reproductive processes. However, the role of TGFβ signaling in uterine decidualization is poorly understood. Recent studies using the Cre-LoxP strategy have shed new light on the critical role of TGFβ signaling machinery in uterine decidualization. Herein, we focus on reviewing exciting findings from studies using both mouse genetics and in vitro cultured human endometrial stromal cells. We also delve into emerging mechanisms that underlie decidualization, such as non-coding RNAs and epigenetic modifications. We envision that future studies aimed at defining the interrelationship among TGFβ signaling circuitries and their potential interactions with epigenetic modifications/non-coding RNAs during uterine decidualization will open new avenues to treat pregnancy complications associated with decidualization deficiencies.

Endometrial Carcinoma: Specific Targeted Pathways

Endometrial cancer (EC) is the most common gynecologic malignancy in the western world with more than 280,000 cases per year worldwide. Prognosis for EC at early stages, when primary surgical resection is the most common initial treatment, is excellent. Five-year survival rate is around 70 %.Several molecular alterations have been described in the different types of EC. They occur in genes involved in important signaling pathways. In this chapter, we will review the most relevant altered pathways in EC, including PI3K/AKT/mTOR, RAS-RAF-MEK-ERK, Tyrosine kinase, WNT/β-Catenin, cell cycle, and TGF-β signaling pathways. At the end of the chapter, the most significant clinical trials will be briefly discussed.This information is important to identify specific targets for therapy.

Novel oestrogen receptor β-selective ligand reduces obesity and depressive-like behaviour in ovariectomized mice

Hormonal changes due to menopause can cause various health problems including weight gain and depressive symptoms. Multiple lines of evidence indicate that oestrogen receptors (ERs) play a major role in postmenopausal obesity and depression. However, little is known regarding the ER subtype-specific effects on obesity and depressive symptoms. To delineate potential effects of ERβ activation in postmenopausal women, we investigated the effects of a novel oestrogen receptor β-selective ligand (C-1) in ovariectomized mice. Uterine weight, depressive behaviour, and weight gain were examined in sham-operated control mice and ovariectomized mice administered placebo, C-1, or 17β-oestradiol (E2). Administration of C-1 or E2 reduced body weight gain and depressive-like behaviour in ovariectomized mice, as assessed by the forced swim test. In addition, administration of E2 to ovariectomized mice increased uterine weight, but administration of C-1 did not result in a significant increase in uterine weight. These results suggest that the selective activation of ERβ in ovariectomized mice may have protective effects against obesity and depressive-like behaviour without causing an increase in uterine weight. The present findings raise the possibility of the application of ERβ-ligands such as C-1 as a novel treatment for obesity and depression in postmenopausal women.

A Smad3-PTEN regulatory loop controls proliferation and apoptotic responses to TGF-β in mouse endometrium

The TGF-β/Smad and the PI3K/AKT signaling pathways are important regulators of proliferation and apoptosis, and their alterations lead to cancer development. TGF-β acts as a tumor suppressor in premalignant cells, but it is a tumor promoter for cancerous cells. Such dichotomous actions are dictated by different cellular contexts. Here, we have unveiled a PTEN-Smad3 regulatory loop that provides a new insight in the complex cross talk between TGF-β/Smad and PI3K/AKT signaling pathways. We demonstrate that TGF-β triggers apoptosis of wild-type polarized endometrial epithelial cells by a Smad3-dependent activation of PTEN transcription, which results in the inhibition of PI3K/AKT signaling pathway. We show that specific Smad3 knockdown or knockout reduces basal and TGF-β-induced PTEN expression in endometrial cells, resulting in a blockade of TGF-β-induced apoptosis and an enhancement of cell proliferation. Likewise Smad3 deletion, PTEN knockout prevents TGF-β-induced apoptosis and increases cell proliferation by increasing PI3K/AKT/mTOR signaling. In summary, our results demonstrate that Smad3-PTEN signaling axis determine cellular responses to TGF-β.

Transplantation of collagen scaffold with autologous bone marrow mononuclear cells promotes functional endometrium reconstruction via downregulating ΔNp63 expression in Asherman's syndrome

Asherman's syndrome (AS) is a common disease that presents endometrial regeneration disorder. However, little is known about its molecular features of this aregenerative endometrium in AS and how to reconstruct the functioning endometrium for the patients with AS. Here, we report that ΔNp63 is significantly upregulated in residual epithelial cells of the impaired endometrium in AS; the upregulated-ΔNp63 induces endometrial quiescence and alteration of stemness. Importantly, we demonstrate that engrafting high density of autologous bone marrow mononuclear cells (BMNCs) loaded in collagen scaffold onto the uterine lining of patients with AS downregulates ΔNp63 expression, reverses ΔNp63-induced pathological changes, normalizes the stemness alterations and restores endometrial regeneration. Finally, five patients achieved successful pregnancies and live births. Therefore, we conclude that ΔNp63 is a crucial therapeutic target for AS. This novel treatment significantly improves the outcome for the patients with severe AS.

Activin receptor-like kinases: a diverse family playing an important role in cancer

The role and function of the members of the TGFβ superfamily has been a substantial area of research focus for the last several decades. During that time, it has become apparent that aberrations in TGFβ family signaling, whether through the BMP, Activin, or TGFβ arms of the pathway, can result in tumorigenesis or contribute to its progression. Downstream signaling regulates cellular growth under normal physiological conditions yet induces diverse processes during carcinogenesis, ranging from epithelial- to-mesenchymal transition to cell migration and invasion to angiogenesis. Due to these observations, the question has been raised how to utilize and target components of these signaling pathways in cancer therapy. Given that these cascades include both ligands and receptors, there are multiple levels at which to interfere. Activin receptor-like kinases (ALKs) are a group of seven type I receptors responsible for TGFβ family signal transduction and are utilized by many ligands within the superfamily. The challenge lies in specifically targeting the often-overlapping functional effects of BMP, Activin, or TGFβ signaling during cancer progression. This review focuses on the characteristic function of the individual receptors within each subfamily and their recognized roles in cancer. We next explore the clinical utility of therapeutically targeting ALKs as some have shown partial responses in Phase I clinical trials but disappointing outcomes when used in Phase II studies. Finally, we discuss the challenges and future directions of this body of work.

Loss of Gata4 in Sertoli cells impairs the spermatogonial stem cell niche and causes germ cell exhaustion by attenuating chemokine signaling

Sertoli cells, the primary somatic cell in the seminiferous epithelium, provide the spermatogonial stem cell (SSC) microenvironment (niche) through physical support and the expression of paracrine factors. However, the regulatory mechanisms within the SSC niche, which is primarily controlled by Sertoli cells, remain largely unknown. GATA4 is a Sertoli cell marker, involved in genital ridge initiation, sex determination and differentiation during the embryonic stage. Here, we showed that neonatal mice with a targeted disruption of Gata4 in Sertoli cells (Gata4(flox/flox); Amh-Cre; hereafter termed Gata4 cKO) displayed a loss of the establishment and maintenance of the SSC pool and apoptosis of both gonocyte-derived differentiating spermatogonia and meiotic spermatocytes. Thus, progressive germ cell depletion and a Sertoli-cell-only syndrome were observed as early as the first wave of murine spermatogenesis. Transplantation of germ cells from postnatal day 5 (P5) Gata4 cKO mice into Kit(W/W-v) recipient seminiferous tubules restored spermatogenesis. In addition, microarray analyses of P5 Gata4 cKO mouse testes showed alterations in chemokine signaling factors, including Cxcl12, Ccl3, Cxcr4 (CXCL12 receptor), Ccr1 (CCL3 receptor), Ccl9, Xcl1 and Ccrl2. Deletion of Gata4 in Sertoli cells markedly attenuated Sertoli cell chemotaxis, which guides SSCs or prospermatogonia to the stem cell niche. Finally, we showed that GATA4 transcriptionally regulated Cxcl12 and Ccl9, and the addition of CXCL12 and CCL9 to an in vitro testis tissue culture system increased the number of PLZF+ undifferentiated spermatogonia within Gata4 cKO testes. Together, these results reveal a novel role for GATA4 in controlling the SSC niche via the transcriptional regulation of chemokine signaling shortly after birth.

Endometrial hyperplasia-related inflammation: its role in the development and progression of endometrial hyperplasia

BACKGROUND

Endometrial hyperplasia (EH) is one of the most common gynecologic diseases in the world. Different statistical categories implicate an imbalance of estrogens and progestogens in the etiology of this disease. We propose that inflammation also plays a key role in the progression of endometrial hyperplasia.

OBJECTIVE

The aim of this study is to evaluate the role of inflammation in the transformation and progression of endometrial hyperplasia, using local inflammatory cytokines and nonspecific protease levels, CD 45(+) expression, and histological examination.

DESIGN

The study included 107 patients (ages 29-49 years) with different forms of endometrial hyperplasia. The enrolled patients were randomized into one of the four groups: normal endometrium (n = 18) as the control group, simple hyperplasia (n = 41), complex hyperplasia without atypia (n = 36), complex atypical hyperplasia or endometrioid adenocarcinoma (n = 12).

METHODS

The following were evaluated for patients with different forms of EH: steroid hormone levels in blood serum and uterine flushings, immunohistochemical estrogen and progesterone receptor expression patterns in the endometrial tissue, CD 45(+) (common leukocyte antigen) expression, the levels of the cytokines IL-1β, IL-6, and TNF-α, and nonspecific proteases and their inhibitors.

RESULTS

The level of estradiol in blood serum and especially in uterine flushings was elevated dramatically in simple EH as compared to that of controls, but there was no significant difference between estradiol levels among the different forms of EH. The estimation of CD 45(+), the levels of the cytokines IL-1β, IL-6, and TNF-α, and the activity of proteases (elastase-like and trypsin-like activities) and their inhibitors showed that levels of nonspecific inflammatory markers increase with EH progression.

CONCLUSIONS

We suggest that the initial responsibility for the development of simple endometrial hyperplasia belongs to systemic hyperestrogenemia and, in particular, local hyperestrogenia, but that the role of inflammatory processes increases in complex and atypical EH. Development of inflammatory changes in endometrial hyperplasia may be considered as a factor in the promotion and progression of pathology, as well as an attributed risk factor for malignancy in endometrial hyperplasia. In this study, we have established a role for CD 45(+) expression cells, non-specific proteases, and the inflammatory cytokines IL-1β, IL-6, and TNF-α in endometrial hyperplasia-related inflammation.

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

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

Transforming growth factor β signaling in uterine development and function

Transforming growth factor β (TGFβ) superfamily is evolutionarily conserved and plays fundamental roles in cell growth and differentiation. Mounting evidence supports its important role in female reproduction and development. TGFBs1-3 are founding members of this growth factor family, however, the in vivo function of TGFβ signaling in the uterus remains poorly defined. By drawing on mouse and human studies as a main source, this review focuses on the recent progress on understanding TGFβ signaling in the uterus. The review also considers the involvement of dysregulated TGFβ signaling in pathological conditions that cause pregnancy loss and fertility problems in women.