Krüppel-like factor 9 deficiency in uterine endometrial cells promotes ectopic lesion establishment associated with activated notch and hedgehog signaling in a mouse model of endometriosis

Decreased expression of KLF6 in ectopic endometrial stromal cells contributes to endometriosis progression by targeting CTNNB1

Despite decades of research, endometriosis remains a mysterious gynecological disease with unknown etiology and pathogenesis. Krüppel-like Factor 6 (KLF6), a transcription factor, has a wide expression profile and regulates a variety of biological processes. Here, we investigated the expression and function of KLF6 and its possible regulatory mechanisms in endometriosis. To determine the function of KLF6, knockdown and overexpression experiments were performed in eutopic endometrial stromal cells (EU-ESCs) and ectopic endometrial stromal cells (EC-ESCs), respectively. Cell viability, apoptosis, migration, invasion, and angiogenesis assays were conducted in ESCs. ChIP-sequencing and mRNA-sequencing were performed to investigate the functional mechanism of KLF6 in regulating ESCs. We found that KLF6 was highly expressed in eutopic endometrium of endometriosis patients, compared with ectopic endometrium. Similarly, the same was true in EU-ESCs, which was compared with EC-ESCs. Overexpression of KLF6 significantly suppressed EC-ESC proliferation, migration and invasion and induced cell apoptosis, while knockdown of KLF6 resulted in the opposite effects on EU-ESCs. Overexpression of KLF6 significantly inhibited EC-ESC angiogenesis. Mechanistically, the results of ChIP sequencing and mRNA sequencing revealed that CTNNB1 may be a transcriptional target regulated by KLF6. Reintroduction of KLF6 reversed the effects of KLF6 knockdown on EU-ESCs. KLF6 inhibited the proliferation, migration and angiogenesis of EC-ESCs by inhibiting the expression of CTNNB1. Our findings provided a new perspective on the role of KLF6 in endometriosis progression and inspire potential targeted therapeutic strategies.

PDLIM3 knockdown promotes ferroptosis in endometriosis progression via inducing Gli1 degradation and blocking Hedgehog signaling pathway

AIMS

Current evidence suggests that there is no completely effective method for endometriosis (EMS) without trauma due to diverse adverse effects. Reliable evidence illustrates that inhibiting ferroptosis is a potential strategy for EMS. We sufficiently verified that the expression of endogenous protein PDZ and LIM domain 3 (PDLIM3) was significantly increased in EMS.

METHODS

PDLIM3 knockdown reduced primary ectopic endometrial stromal cells' (EESCs) viability and migration, and elevated ferroptosis signaling indicators including Fe2+, malondialdehyde (MDA), and reactive oxygen species (ROS) in EESCs.

RESULTS

Mechanistic studies revealed that inhibition of PDLIM3 accelerated glioma-associated oncogene-1 (Gli1) degradation and further deactivated Hedgehog signaling. Gli1 inhibitor, GANT61, abrogated the impact of PDLIM3 deletion on EESC growth, migration, and ferroptosis. In vivo experiments suggested that PDLIM3 reduction repressed the growth of endometrial lesions. Likewise, repression of PDLIM3 promoted ferroptosis and attenuated Hedgehog signaling in endometrial lesions.

CONCLUSIONS

Collectively, silencing of PDLIM3 facilitates ferroptosis in EMS by inducing Gli1 degradation and blocking Hedgehog signaling. It may provide an alternative strategy for developing therapeutic agents of EMS in the future.

Krüppel-like Factor-9 and Krüppel-like Factor-13: Highly Related, Multi-Functional, Transcriptional Repressors and Activators of Oncogenesis

Specificity Proteins/Krüppel-like Factors (SP/KLF family) are a conserved family of transcriptional regulators. These proteins share three highly conserved, contiguous zinc fingers in their carboxy-terminus, requisite for binding to cis elements in DNA. Each SP/KLF protein has unique primary sequence within its amino-terminal and carboxy-terminal regions, and it is these regions which interact with co-activators, co-repressors, and chromatin-modifying proteins to support the transcriptional activation and repression of target genes. Krüppel-like Factor 9 (KLF9) and Krüppel-like Factor 13 (KLF13) are two of the smallest members of the SP/KLF family, are paralogous, emerged early in metazoan evolution, and are highly conserved. Paradoxically, while most similar in primary sequence, KLF9 and KLF13 display many distinct roles in target cells. In this article, we summarize the work that has identified the roles of KLF9 (and to a lesser degree KLF13) in tumor suppression or promotion via unique effects on differentiation, pro- and anti-inflammatory pathways, oxidative stress, and tumor immune cell infiltration. We also highlight the great diversity of miRNAs, lncRNAs, and circular RNAs which provide mechanisms for the ubiquitous tumor-specific suppression of KLF9 mRNA and protein. Elucidation of KLF9 and KLF13 in cancer biology is likely to provide new inroads to the understanding of oncogenesis and its prevention and treatments.

Cross talk of tumor protein D52 (TPD52) with KLF9, PKCε, and MicroRNA 223 in ovarian cancer

BACKGROUND

Gynecologic cancers comprise malignancies in the female reproductive organs. Ovarian cancer ranks sixth in terms of incidence rates while seventh in terms of mortality rates. The stage at which ovarian cancer is diagnosed mainly determines the survival outcomes of patients. Various screening approaches are presently employed for diagnosing ovarian cancer; however, these techniques have low accuracy and are non-specific, resulting in high mortality rates of patients due to this disease. Hence, it is crucial to identify improved screening and diagnostic markers to overcome this cancer. This study aimed to find new biomarkers to facilitate the prognosis and diagnosis of ovarian cancer.

METHODS

Bioinformatics approaches were used to predict the tertiary structure and cellular localization along with phylogenetic analysis of TPD52. Its molecular interactions were determined through KEGG analysis, and real-time PCR-based expression analysis was performed to assess its co-expression with another oncogenic cellular pathway (miR-223, KLF9, and PKCε) proteins in ovarian cancer.

RESULTS

Bioinformatics analysis depicted the cytoplasmic localization of TPD52 and the high conservation of its coiled-coil domains. Further study revealed that TPD52 mRNA and miRNA-223 expression was elevated, while the expression of KLF 9 and PKCε was reduced in the blood of ovarian cancer patients. Furthermore, TPD52 and miR-223 expression were upregulated in the early stages of cancer and non-metastatic cancers.

CONCLUSION

TPD52, miR-223, PKCε, and KLF9, can be used as a blood based markers for disease prognosis, metastasis, and treatment response. The study outcomes hold great potential to be translated at the clinical level after further validation on larger cohorts.

Molecular Mechanisms of Endometriosis Revealed Using Omics Data

Endometriosis is a gynecological disorder prevalent in women of reproductive age. The primary symptoms include dysmenorrhea, irregular menstruation, and infertility. However, the pathogenesis of endometriosis remains unclear. With the advent of high-throughput technologies, various omics experiments have been conducted to identify genes related to the pathophysiology of endometriosis. This review highlights the molecular mechanisms underlying endometriosis using omics. When genes identified in omics experiments were compared with endometriosis disease genes identified in independent studies, the number of overlapping genes was moderate. However, the characteristics of these genes were found to be equivalent when functional gene set enrichment analysis was performed using gene ontology and biological pathway information. These findings indicate that omics technology provides invaluable information regarding the pathophysiology of endometriosis. Moreover, the functional characteristics revealed using enrichment analysis provide important clues for discovering endometriosis disease genes in future research.

Krüppel-like factor 9 (KLF9) links hormone dysregulation and circadian disruption to breast cancer pathogenesis

BACKGROUND

Circadian disruption is an emerging driver of breast cancer (BCa), with epidemiological studies linking shift work and chronic jet lag to increased BCa risk. Indeed, several clock genes participate in the gating of mitotic entry, regulation of DNA damage response, and epithelial-to-mesenchymal transition, thus impacting BCa etiology. Dysregulated estrogen (17β-estradiol, E2) and glucocorticoid (GC) signaling prevalent in BCa may further contribute to clock desynchrony by directly regulating the expression and cycling dynamics of genes comprising the local breast oscillator. In this study, we investigated the tumor suppressor gene, Krüppel-like factor 9 (KLF9), as an important point of crosstalk between hormone signaling and the circadian molecular network, and further examine its functional role in BCa.

METHODS

Through meta-analysis of publicly available RNA- and ChIP-sequencing datasets from BCa tumor samples and cell lines, and gene expression analysis by RT-qPCR and enhancer- reporter assays, we elucidated the molecular mechanism behind the clock and hormone regulation of KLF9. Lentiviral knockdown and overexpression of KLF9 in three distinct breast epithelial cell lines (MCF10A, MCF7 and MDA-MB-231) was generated to demonstrate the role of KLF9 in orthogonal assays on breast epithelial survival, proliferation, apoptosis, and migration.

RESULTS

We determined that KLF9 is a direct GC receptor target in mammary epithelial cells, and that induction is likely mediated through coordinate transcriptional activation from multiple GC-responsive enhancers in the KLF9 locus. More interestingly, rhythmic expression of KLF9 in MCF10A cells was abolished in the highly aggressive MDA-MB-231 line. In turn, forced expression of KLF9 altered the baseline and GC/E2-responsive expression of several clock genes, indicating that KLF9 may function as a regulator of the core clock machinery. Characterization of the role of KLF9 using complementary cancer hallmark assays in the context of the hormone-circadian axis revealed that KLF9 plays a tumor-suppressive role in BCa regardless of molecular subtype. KLF9 potentiated the anti-tumorigenic effects of GC in E2 receptor + luminal MCF7 cells, while it restrained GC-enhanced oncogenicity in triple-negative MCF10A and MDA-MB-231 cells.

CONCLUSIONS

Taken together, our findings support that dysregulation of KLF9 expression and oscillation in BCa impinges on circadian network dynamics, thus ultimately affecting the BCa oncogenic landscape.

A Pilot Study on the Co-existence of Diabetes and Endometriosis in Reproductive-Age Women: Potential for Endometriosis Progression

Endometriosis (ENDO) is a chronic estrogen-dependent gynecological condition that affects reproductive-age women, causing pelvic pain, infertility, and increased risk for ovarian cancer. Diabetes mellitus (DM) is a metabolic disease with significant morbidity and mortality and rising incidence worldwide. The occurrence of DM among ENDO patients remains understudied, despite commonalities in these conditions' immune, inflammatory, and metabolic dysfunctions. This pilot study evaluated whether a subset of women with ENDO manifests DM co-morbidity and if so, whether DM promotes ENDO status. Archived ectopic lesions obtained at ENDO surgery from non-diabetic (ENDO-N; n = 11) and diabetic (ENDO-DM; n = 15) patients were identified by a search of an electronic health database. Retrieved samples were analyzed by immunohistochemistry for markers of proliferation (Ki67, PTEN), steroid receptor signaling (ESR, PGR) and macrophage infiltration (CD68). Immunostaining data were expressed as percentages of immune-positive cells in lesion stroma and epithelium. In lesion stroma, the percentages of nuclear immune-positive cells were higher for ESR2 and lower for PGR-T, in ENDO-DM than ENDO-N patients. The percentages of nuclear immune-positive cells for ESR1 and PTEN tended to be higher and lower, respectively, in ENDO-DM than ENDO-N groups. In lesion glandular epithelium, the percentages of nuclear immune-positive cells were higher for ESR1 and ESR2, in ENDO-DM than ENDO-N groups. ENDO-N lesions had lower percentages of stromal CD68 immune-positive cells than ENDO-DM Type 1 lesions. Findings demonstrate DM in a subset of women with ENDO, which was associated with significant changes in lesion stromal and epithelial nuclear steroid hormone receptor levels, suggestive of disease progression.

Prognostic value and immunological role of Kruppel-like transcription factor 9 gene in pan-carcinoma

OBJECTIVE

To investigate the correlation between the expression of Kruppel-like transcription factor 9 (KLF9) and the prognostic value of tumors as well as its relationship with tumor immune invasion.

METHODS

A series of bioinformatics methods were used to analyze the relationship between KLF9 and tumor prognosis, tumor mutation burden, microsatellite instability (MSI), and immune cell infiltration in multiple carcinomas.

RESULTS

In multiple tumor tissues, the expression of KLF9 was lower compared with paracancerous tissues. Therefore, KLF9 can serve as a protective factor to improve the prognosis of carcinoma patients with certain tumor types. KLF9 was closely related to the clinical staging of various carcinomas. The expression of KLF9 was not only associated with tumor mutation burden and MSI in some tumor types, but also positively correlated with immune and stromal cells in multiple tumors. Further studies have found that, the level of immune cell infiltration was significantly related to the expression of KLF9.

CONCLUSION

KLF9 can affect the prognosis of pan-carcinoma, which is related to immune invasion. Therefore, KLF9 can be used as a potential biomarker for the prognosis of pan-carcinoma.

Dienogest May Reduce Estradiol- and Inflammatory Cytokine-Induced Cell Viability and Proliferation and Inhibit the Pathogenesis of Endometriosis: A Cell Culture- and Mouse Model-Based Study

Dienogest (DNG) is a therapeutic medication used in endometriosis treatment. Limited data are available regarding its mechanism of action on endometrial cells. Using in vivo and in vitro models, we investigated whether DNG treatment causes significant biological changes in human endometrial stromal cells (ESCs). The markers related to the pathogenesis of endometriosis in ESCs were evaluated using estradiol, tumor necrosis factor alpha (TNF-α), interleukin 1β (IL-1β), and IL-32, administered alone or in combination with DNG. Implanted endometrial tissues were compared between C57BL/6 mice that did or did not receive DNG treatment by using size measurements and immunohistochemistry. A significant decrease in cell viability, protein kinase B (AKT) phosphorylation, and the expression of p21-activated kinase 4 and vascular endothelial growth factor were observed in ESCs treated with estradiol plus DNG. Cell viability, AKT phosphorylation, and proliferating cell nuclear antigen (PCNA) expression also decreased significantly after TNF-α plus DNG treatment. Treatment with IL-1β or IL-32 plus DNG significantly decreased cell viability or PCNA expression, respectively. The size of the implanted endometrial tissue significantly decreased in mice treated with DNG, accompanied by decreased PCNA expression. Thus, DNG may reduce cell viability and proliferation induced by estradiol, TNF-α, IL-1β, and IL-32, and inhibit the endometriosis pathogenesis by decreasing PCNA expression.

Effects of an inhibitor of the SHH signaling pathway on endometrial cells of patients with endometriosis

Background

Endometriosis is one of the most common gynecological diseases, and seriously reduces the quality of life of patients. However, the pathogenesis of this disease is unclear. Therefore, more studies are needed to elucidate its pathogenesis. Our previous publication found that the Sonic Hedgehog (SHH) signaling pathway was activated in endometriosis. This study tested whether SHH signaling in endometrial stromal cells (ESCs) was critical for the pathogenesis of endometriosis.

Methods

To examine the effect of inhibiting the SHH signaling pathway on endometriosis, we first isolated ESCs from eutopic endometrial tissues of patients with or without endometriosis and identified the extracted cells by morphological observation and immunofluorescence. Then, we treated ESCs with the GLI inhibitor GANT61 and used CCK-8, wound healing and invasion assays to detect cell activities, such as proliferation, invasion and metastasis. Furthermore, we detected the expression of key proteins and proliferation markers of the SHH signaling pathway in the lesions of nude mice using immunochemistry.

Results

We demonstrated that higher concentrations of GANT61 decreased the proliferation rate and migration distance of ESCs. We observed that GANT61 inhibited the invasion of ESCs. In addition, blockage of the SHH signaling pathway significantly reduced cell proliferation in vitro.

Conclusions

Our study suggested that inhibition of the SHH pathway is involved in cell proliferation and invasive growth in the pathogenesis of endometriosis.

Predicting 3D Structure, Cross Talks, and Prognostic Significance of KLF9 in Cervical Cancer

Our study aimed to identify the new blood-based biomarkers for the diagnosis and prognosis of cervical cancer. Moreover, the three-dimensional (3D) structure of Kruppel-like factor 9 (KLF9) was also determined in order to better understand its function, and a signaling pathway was constructed to identity its upstream and downstream targets. In the current study, the co-expressions of tumor protein D52 (TPD52), KLF9, microRNA 223 (miR-223), and protein kinase C epsilon (PKCϵ) were evaluated in cervical cancer patients and a possible relation with disease outcome was revealed. The expressions of TPD52, KLF9, miR-223, and PKCϵ were studied in the blood of 100 cervical cancer patients and 100 healthy controls using real-time PCR. The 3D structure of KLF9 was determined through homology modeling via the SWISS-MODEL and assessed using the Ramachandran plot. The predicted 3D structure of KLF9 had a similarity index of 62% with its template (KLF4) with no bad bonds in it. In order to construct a genetic pathway, depicting the crosstalk between understudied genes, STRING analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG), and DAVID software were used. The constructed genetic pathway showed that all the understudied genes are linked to each other and involved in the PI3K/Akt signaling pathway. There was a 23-fold increase in TPD52 expression, a 2-fold increase in miR-223 expression, a 0.14-fold decrease in KLF9 expression, and a 0.05-fold decrease of PKCϵ expression in cervical cancer. In the present study, we observed an association of the expressions of TPD52, KLF9, miR-223, and PKCϵ with tumor stage, metastasis, and treatment status of cervical cancer patients. Elevated expressions of TPD52 and miR-223 and reduced expressions of KLF9 and PKCϵ in peripheral blood of cervical cancer patients may serve as predictors of disease diagnosis and prognosis. Nevertheless, further in vitro and tissue-level studies are required to strengthen their role as potential diagnostic and prognostic biomarkers.

Lesion Genotype Modifies High-Fat Diet Effects on Endometriosis Development in Mice

Endometriosis is a chronic, estrogen-dependent gynecologic disorder that affects reproductive-aged women and to a lesser extent, post-menopausal women on hormone therapy. The condition is associated with systemic and local immune dysfunctions. While its underlying mechanisms remain poorly understood, endometriosis has a genetic component and propensity for the disease is subject to environmental, nutritional, and lifestyle influences. Previously, we showed that high-fat diet (HFD) increased ectopic lesion numbers, concurrent with systemic and peritoneal changes in inflammatory and oxidative stress status, in immunocompetent recipient mice ip administered with endometrial fragments null for Krüppel-like factor 9 gene. Herein, we determined whether HFD modifies lesion parameters, when recipient peritoneal environment is challenged with ectopic wild-type (WT) endometrial fragments, the latter simulating retrograde menstruation common in women during the menstrual period. WT endometrium-recipient mice fed HFD (45% kcal from fat) showed reduced lesion incidence, numbers, and volumes, in the absence of changes in systemic ovarian steroid hormone and insulin levels, relative to those fed the control diet (CD, 17% kcal from fat). Lesions from HFD- and CD-fed recipients demonstrated comparable gene expression for steroid hormone receptors (Esr and Pgr) and cytokines (Il-6, Il-8, and CxCL4) and similar levels of DNA oxidative biomarkers. HFD moderately altered serum (3-nitrotyrosine and methionine/homocysteine) and peritoneal (reduced glutathione/oxidized glutathione) pro-oxidative status but had no effect on peritoneal inflammatory (tumor necrosis factor α and tumor necrosis factor receptor 1) mediators. Results indicate that lesion genotype modifies dietary effects on disease establishment and/or progression and if translated, could be important for provision of nutritional guidelines to women with predisposition to, or affected by endometriosis.

Exosomes and their cargo are important regulators of cell function in endometriosis

Endometriosis is a chronic oestrogen-dependent gynaecological disorder characterized by non-menstrual pelvic pain, infertility and the extrauterine growth of endometrial-like glands and stroma. It has been noted that the eutopic endometrium of women with endometriosis is functionally distinct from that of women without endometriosis. Moreover, ectopic endometrial implants are functionally different from the eutopic endometrium of women with endometriosis. However, the mechanisms directing these differences are ill-defined. It is proposed here that small membrane-bound extracellular vesicles called exosomes are important vehicles in the protection and transport of signalling molecules central to the dysregulation of endometrial function in women with endometriosis. Therefore, a critical review of the literature linking exosomes and their cargo to the pathobiology of endometriosis was conducted. Circulating peritoneal fluid and endometrial cell exosomes contained long non-coding RNA, miRNA and proteins involved in histone modification, angiogenesis and immune modulation that differed significantly in women with endometriosis compared with controls. Moreover, experimental evidence supports a role for exosomes and their cargo in angiogenesis, neurogenesis, immune modulation and endometrial stromal cell invasion. It is therefore suggested that exosomes play an important role in the pathophysiology of endometriosis.

The effects of hedgehog ligand neutralising antibody 5E1 in a mouse model of endometriosis

Objective

Endometriosis is a common and painful condition characterised by the formation of endometrial lesions within the peritoneal cavity. Previous studies have suggested a role for hedgehog signalling in the pathogenesis of endometriosis. We investigated the role of hedgehog signalling in the establishment of endometriosis lesions using 5E1, a hedgehog ligand neutralising antibody, and a mouse model of endometriosis. To mimic the initiation of endometriosis by retrograde menstruation, which is believed to occur in humans, donor mice underwent an artificial menstruation protocol. Fragments of menstrual endometrium were injected into the peritoneal cavity of estrogen primed recipients. Recipients received twice weekly injections of 5E1 or an isotype matched control antibody for three weeks. Lesions were collected and analysed for markers of epithelium, proliferation and apoptosis by immunofluorescence microscopy.

Results

Treatment with 5E1 reduced the number of lesions found on the mesentery. No significant changes were found in the size of lesions, abundance of endometrial epithelial cells, proliferation or apoptosis.

Krüppel-like factor 17 upregulates uterine corin expression and promotes spiral artery remodeling in pregnancy

Spiral artery remodeling is an important physiological process in the pregnant uterus which increases blood flow to the fetus. Impaired spiral artery remodeling contributes to preeclampsia, a major disease in pregnancy. Corin, a transmembrane serine protease, is up-regulated in the pregnant uterus to promote spiral artery remodeling. To date, the mechanism underlying uterine corin up-regulation remains unknown. Here we show that Krüppel-like factor (KLF) 17 is a key transcription factor for uterine corin expression in pregnancy. In cultured human uterine endometrial cells, KLF17 binds to the CORIN promoter and enhances the promoter activity. Disruption of the KLF17 gene in the endometrial cells abolishes CORIN expression. In mice, Klf17 is up-regulated in the pregnant uterus. Klf17 deficiency prevents uterine Corin expression in pregnancy. Moreover, Klf17-deficient mice have poorly remodeled uterine spiral arteries and develop gestational hypertension and proteinuria. Together, our results reveal an important function of KLF17 in regulating Corin expression and uterine physiology in pregnancy.

Uncovering Potential Roles of Differentially Expressed Genes, Upstream Regulators, and Canonical Pathways in Endometriosis Using an In Silico Genomics Approach

Endometriosis is characterized by ectopic endometrial tissue implantation, mostly within the peritoneum, and affects women in their reproductive age. Studies have been done to clarify its etiology, but the precise molecular mechanisms and pathophysiology remain unclear. We downloaded genome-wide mRNA expression and clinicopathological data of endometriosis patients and controls from NCBI’s Gene Expression Omnibus, after a systematic search of multiple independent studies comprising 156 endometriosis patients and 118 controls to identify causative genes, risk factors, and potential diagnostic/therapeutic biomarkers. Comprehensive gene expression meta-analysis, pathway analysis, and gene ontology analysis was done using a bioinformatics-based approach. We identified 1590 unique differentially expressed genes (129 upregulated and 1461 downregulated) mapped by IPA as biologically relevant. The top upregulated genes were FOS, EGR1, ZFP36, JUNB, APOD, CST1, GPX3, and PER1, and the top downregulated ones were DIO2, CPM, OLFM4, PALLD, BAG5, TOP2A, PKP4, CDC20B, and SNTN. The most perturbed canonical pathways were mitotic roles of Polo-like kinase, role of Checkpoint kinase proteins in cell cycle checkpoint control, and ATM signaling. Protein–protein interaction analysis showed a strong network association among FOS, EGR1, ZFP36, and JUNB. These findings provide a thorough understanding of the molecular mechanism of endometriosis, identified biomarkers, and represent a step towards the future development of novel diagnostic and therapeutic options.

Analysis of exosomal lncRNA, miRNA and mRNA expression profiles and ceRNA network construction in endometriosis

Aim: To investigate exosomal RNAs (long noncoding RNAs (lncRNAs), microRNAs (miRNAs) and messenger RNAs (mRNAs)) profiling and their related networks in endometriosis (EMs). Materials & methods: RNA sequence was performed in exosomes from ovarian endometriomas (EC), eutopic endometria (EU) and normal endometria (Control) stromal cells. The bioinformatics algorithms evaluated competing endogenous RNA (ceRNA) networks. The top-ranked ceRNA networks were confirmed by RT-PCR. Results: Overlapped differentially expressed 938 lncRNAs, 39 miRNAs and 1449 mRNAs were identified. 13 co-expression modules and 61 ceRNA networks were constructed. Conclusion: This study for the first time shows exosomal RNA biomarkers and lncRNA-related networks in EMs, which reveals a novel molecular mechanism of EMs and provides new resources for EM diagnosis and treatment.

Interleukin-6 (IL-6) Activates the NOTCH1 Signaling Pathway Through E-Proteins in Endometriotic Lesions

CONTEXT

NOTCH signaling is activated in endometriotic lesions, but the exact mechanisms remains unclear. IL-6, which is increased in the peritoneal fluid of women with endometriosis, induces NOTCH1 through E-proteins including E2A and HEB in cancer.

OBJECTIVE

To study the role of E-proteins in inducing NOTCH1 expression under the regulation of IL-6 in endometriosis.

SETTING AND DESIGN

The expression of E-proteins and NOTCH1 was first investigated in endometrium of women with endometriosis and the baboon model of endometriosis. Regulation of E-proteins and NOTCH1 expression was examined after IL-6 stimulation and siRNA mediated inhibition of E2A or/and HEB in human endometriotic epithelial cells (12Z) in vitro, and subsequently following IL-6 treatment in the mouse model of endometriosis in vivo.

RESULTS

E2A, HEB, and NOTCH1 were significantly upregulated in glandular epithelium (GE) of ectopic endometrium compared to eutopic endometrium in both women and the baboon model. IL-6 treatment upregulated the expression of NOTCH1 together with E2A and HEB in 12Z cells. Small interfering RNA inhibition of E2A and HEB or HEB alone decreased NOTCH1 expression. Binding efficiency of both E2A and HEB was significantly higher at the binding sites on the human NOTCH1 promoter after IL-6 treatment. Finally, IL-6 treatment resulted in a significantly increased number of endometriotic lesions along with increased expression of E2A, HEB, and NOTCH1 in GE of the lesions compared with the vehicle group in an endometriosis mouse model.

CONCLUSIONS

IL-6 induced NOTCH1 expression is mediated by E-proteins in the ectopic GE cells, which may promote endometriotic lesion development.

Krüppel-like factor 9 promotes neuroblastoma differentiation via targeting the sonic hedgehog signaling pathway

BACKGROUND

Neuroblastoma (NB) is a deadly solid tumor of children. Krüppel-like factor 9 (KLF9) has prodifferentiation and tumor suppression functions in several types of cancers. Here, we aimed to investigate the effects of KLF9 on NB differentiation and growth and to elucidate the underlying mechanism.

PROCEDURE

Sixty-five NB paraffin samples were assessed for expression levels of KLF9 and sonic hedgehog (SHH) signaling pathway proteins by immunohistochemistry. The associations between expression of KLF9 and the SHH pathway components and patients' clinicopathologic characteristics were estimated. The impacts of KLF9 on cell differentiation, proliferation, and invasion were investigated in two NB cell lines (SH-SY5Y and IMR32). Additionally, chromatin immunoprecipitation (ChIP) and luciferase reporter assays were used to elucidate the mechanism by which KLF9 regulates SHH signaling.

RESULTS

Differentiating NB specimens showed significantly higher KLF9 expression levels than undifferentiated/poorly differentiated ones. Moreover, increased KLF9 expression was associated with favorable prognoses in patients with NB. A negative correlation was found between KLF9 and SHH signaling expression levels in NB specimens. In vitro assays revealed that KLF9 promoted the differentiation of NB cells and inhibited their proliferation and invasion via suppression of the SHH pathway. Furthermore, KLF9 binding sites in the SHH promoter were identified by ChIP and luciferase reporter assays.

CONCLUSIONS

KLF9 exerts prodifferentiation and growth-inhibition effects on NB via suppression of the SHH pathway, suggesting a potential role of KLF9 in NB therapy.

CXCR4 or CXCR7 antagonists treat endometriosis by reducing bone marrow cell trafficking

Adult stem cells have a major role in endometrial physiology, including remodelling and repair. However, they also have a critical role in the development and progression of endometriosis. Bone marrow-derived stem cells engraft eutopic endometrium and endometriotic lesions, differentiating to both stromal and epithelial cell fates. Using a mouse bone marrow transplantation model, we show that bone marrow-derived cells engrafting endometriosis express CXCR4 and CXCR7. Targeting either receptor by the administration of small molecule receptor antagonists AMD3100 or CCX771, respectively, reduced BM-derived stem cell recruitment into endometriosis implants. Endometriosis lesion size was decreased compared to vehicle controls after treatment with each antagonist in both an early growth and established lesion treatment model. Endometriosis lesion size was not effected when the local effects of CXCL12 were abrogated using uterine-specific CXCL12 null mice, suggesting an effect primarily on bone marrow cell migration rather than a direct endometrial effect. Antagonist treatment also decreased hallmarks of endometriosis physiopathology such as pro-inflammatory cytokine production and vascularization. CXCR4 and CXCR7 antagonists are potential novel, non-hormonal therapies for endometriosis.

Dysregulation of miR-202-3p Affects Migration and Invasion of Endometrial Stromal Cells in Endometriosis via Targeting ROCK1

Dysregulation of microRNAs in endometrial cells plays a pivotal role in the pathogenesis of endometriosis (EM). This study aims to investigate the implication of aberrant miR-202-3p expression in EM and the underlying mechanisms. We demonstrated that miR-202-3p was significantly downregulated in eutopic endometrium of EM in comparison to normal endometrial samples (P < 0.05). Primary endometrial stromal cells (ESCs) isolated from eutopic or ectopic endometrium also showed a significant decrease in miR-202-3p level compared to ESCs from normal endometrium (P < 0.01). Functional studies using MTT, wound healing assay and transwell assay indicated that overexpression of miR-202-3p greatly impaired cell viability, migration, and invasion, whereas suppression of miR-202-3p exhibited the opposite effects (P < 0.05 or P < 0.01). miR-202-3p mimics or inhibitors transfection significantly decreased or increased expression of Rho-associated, coiled-coil containing protein kinase 1 (ROCK1), respectively, in ESCs (P < 0.01). Using dual luciferase reporter assay, we validated ROCK1 as a direct target of miR-202-3p. Moreover, negative correlations between miR-202-3p and ROCK1 mRNA/protein levels were determined in both eutopic and normal control endometrium (P < 0.01). In conclusion, these findings suggest that suppression of miR-202-3p in ESCs results in enhanced cell viability, invasion, and migration at least partially via upregulation of its target ROCK1, which eventually contributes to the development of endometriosis.

GLI1 is increased in ovarian endometriosis and regulates migration, invasion and proliferation of human endometrial stromal cells in endometriosis

BACKGROUND

Endometriosis is a benign gynecological disorder which shares certain characteristics with malignant tumor like migration, invasion and proliferation. Glioma-associated oncogene homolog 1 (GLI1) has been implicated in some cancers including endometrial cancer, however, its role in endometriosis remains unknown.

METHODS

The aim of this study was to explore the expression pattern of GLI1 in endometriosis, and further investigate the effect of GLI1 regulation on human endometrial stromal cells. The expression of GLI1 in normal endometrium and ectopic tissues was analyzed by immunohistochemistry, quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and western blot. The Short hairpin RNA (ShRNA) intervention technique and GLI1 inhibitor GANT-61 were used to silence GLI1. The expression levels of GLI1, MMP2 and MMP9 was detected by qRT-PCR and western blot. The migration and invasion ability of human endometrial stromal cells was determined by wound healing assay and transwell migration/invasion assay. The viability and proliferation potentiality of cells was detected by MTT assays and colony formation assay, respectively.

RESULTS

We found that the expression of GLI1 mRNA and protein were significantly higher in ectopic endometrium from patients with endometriosis. Our analyses also show that GLI1 downregulation attenuated cells migration, invasion and proliferation abilities. What's more, reduced expression of GLI1 inhibited the expression of matrix metalloproteinase 2 (MMP2) and matrix metalloproteinase 9 (MMP9).

CONCLUSIONS

Our findings suggest that high levels of GLI1 may contribute to the development of endometriosis by promoting cell migration, invasion and proliferation involving regulation of MMP2 and MMP9 expression. Therefore, inhibition of GLI1 might be a novel potential therapeutic approach to the treatment of endometriosis, which sheds new light on our understanding of the pathogenesis of endometriosis.

Aberrant expression of genes associated with stemness and cancer in endometria and endometrioma in a subset of women with endometriosis

STUDY QUESTION

Is there molecular evidence for a link between endometriosis and endometriosis-associated ovarian cancers (EAOC)?

STUDY ANSWER

We identified aberrant gene expression signatures associated with malignant transformation in a small subgroup of women with ovarian endometriosis.

WHAT IS KNOWN ALREADY

Epidemiological studies have shown an increased risk of EAOC in women with ovarian endometriosis. However, the cellular and molecular changes leading to EAOC are largely unexplored.

STUDY DESIGN, SIZE, DURATION

CD73+CD90+CD105+ multipotent stem cells/progenitors (SC cohort) were isolated from endometrium (n = 18) and endometrioma (n = 11) of endometriosis patients as well as from the endometrium of healthy women (n = 14). Extensive phenotypic and functional analyses were performed in vitro on expanded multipotent stem cells/progenitors to confirm their altered characteristics. Aberrant gene signatures were also validated in paired-endometrium and -endometrioma tissue samples from another cohort (Tissue cohort, n = 19) of endometriosis patients.

PARTICIPANTS/MATERIALS, SETTINGS, METHODS

Paired-endometrial and -endometriotic biopsies were obtained from women with endometriosis (ASRM stage III-IV) undergoing laparoscopic surgery. Control endometria were obtained from healthy volunteers. Isolated CD73+CD90+CD105+ SC were evaluated for the presence of known endometrial surface markers, colony forming efficiency, multi-lineage differentiation, cell cycle distribution and 3D-spheroid formation capacity. Targeted RT-PCR arrays, along with hierarchical and multivariate clustering tools, were used to determine both intergroup and intragroup gene expression variability for stem cell and cancer-associated markers, in both SC+ and tissue cohorts.

MAIN RESULTS AND THE ROLE OF CHANCE

Isolated and expanded SC+ from both control and patient groups showed significantly higher surface expression of W5C5+, clonal expansion and 3D-spheroid formation capacity (P < 0.05) compared with SC-. The SC+ cells also undergo mesenchymal lineage differentiation, unlike SC-. Gene expression from paired-endometriosis samples showed significant downregulation of PTEN, ARID1A and TNFα (P < 0.05) in endometrioma compared with paired-endometrium SC+ samples. Hierarchical and multivariate clustering from both SC+ and tissue cohorts together identified 4 out of 30 endometrioma samples with aberrant expression of stem cell and cancer-associated genes, such as KIT, HIF2α and E-cadherin, altered expression ratio of ER-β/ER-α and downregulation of tumour suppressor genes (PTEN and ARID1A). Thus, we speculate that above changes may be potentially relevant to the development of EAOC.

LARGE-SCALE DATA

N/A.

LIMITATIONS, REASON FOR CAUTION

As the reported frequency of EAOC is very low, we did not have access to those samples in our study. Moreover, by adopting a targeted gene array approach, we might have missed several other potentially-relevant genes associated with EAOC pathogenesis. The above panel of markers should be further validated in archived tissue samples from women with endometriosis who later in life developed EAOC.

WIDER IMPLICATIONS OF THE FINDINGS

Knowledge gained from this study, with further confirmation on EAOC cases, may help in developing screening methods to identify women with increased risk of EAOC.

STUDY FUNDING/COMPETING INTEREST(S)

The study is funded by the Swedish Research Council (2012-2844), a joint grant from Stockholm County and Karolinska Institutet (ALF), RGD network at Karolinska Institutet, Karolinska Institutet for doctoral education (KID), Estonian Ministry of Education and Research (IUT34-16), Enterprise Estonia (EU48695), Horizon 2020 innovation program (WIDENLIFE, 692065), European Union's FP7 Marie Curie Industry-Academia Partnerships and Pathways funding (IAPP, SARM, EU324509) and MSCA-RISE-2015 project MOMENDO (691058). All authors have no competing interest.

Notch-1 Signaling Activation and Progesterone Receptor Expression in Ectopic Lesions of Women With Endometriosis

Context

Progesterone (P) resistance is a hallmark of endometriosis, but the underlying mechanism(s) for loss of P sensitivity leading to lesion establishment remains poorly understood.

Objective

To evaluate the association between Notch-1 signaling activation and P resistance in the progression of endometriosis.

Design

Case control study; archived formalin-fixed, paraffin-embedded tissues.

Setting

University hospitals (United States, Taiwan).

Patients

Women with endometriosis; human endometrial stromal cell line (HESC).

Intervention

Eutopic endometria (EU) and ectopic lesions (ECs) were collected from surgically diagnosed patients. Archived tissue sections of EU and ECs were identified. HESCs were treated with N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester (DAPT) and valproic acid (VPA) to, respectively, suppress and induce Notch-1 activation.

Outcome Measures

Tissues were analyzed for Notch Intra-Cellular Domain 1 (NICD1) and progesterone receptor (PGR) protein expression by immunohistochemistry and for transcript levels of NICD1 target genes HES1, PGR, and PGR-B by quantitative reverse transcription polymerase chain reaction. DAPT- or VPA-treated HESCs with and without P cotreatment were evaluated for cell numbers and for PGR, HES1, and PGR target gene DKK1 transcript levels.

Results

Nuclear-localized stromal NICD1 protein levels were inversely associated with those of total PGR in EU and ECs. Stromal ECs displayed higher HES1 and lower total PGR and PGR-B transcript levels than EU. In HESCs, DAPT reduction of NICD1 decreased cell numbers and increased PGR transcript and nuclear PGR protein levels and, with P cotreatment, maintained P sensitivity. Conversely, VPA induction of NICD1 decreased PGR transcript levels and, with P cotreatment, abrogated P-induced DKK1 and maintained HES1 transcript levels.

Conclusions

Aberrant Notch-1 activation is associated with decreased PGR that contributes to P resistance in endometriosis.

Epithelial-to-mesenchymal transition in the development of endometriosis

Endometriosis, an estrogen-dependent chronic gynecological disease, is common in reproductive-age women and profoundly affects their life quality. Although various pathogenic theories have been proposed, the origin of endometriosis remains unclear. Epithelial to mesenchymal transition (EMT) is a process that epithelial cells lose polarized organization of the cytoskeleton and cell-to-cell contacts, acquiring the high motility of mesenchymal cells. These changes are thought to be prerequisites for the original establishment of endometriotic lesions. However, no study exactly indicates which type of EMT occurs in endometriosis. In this review, we conclude that two different types of EMT may participate in this disease. Besides, two stimulating signals, hypoxia and estrogen, can through different pathways to activate the EMT process in endometriosis. Those pathways involve many cellular factors such as TGF-beta and Wnt, ultimately leading to cell proliferation and migration. As infertility is becoming a serious and intractable issue for women, EMT, during the implantation process, is gaining attention. In this review, we will describe the known functions of EMT in endometriosis, and suggest further studies that may aid in the development of medical therapy.

Diet and endometriosis-revisiting the linkages to inflammation

Endometriosis is a chronic inflammatory condition that may cause pelvic pain, dysmenorrhea, and/or infertility in women of reproductive age. While treatments may include medical or surgical management, the majority of therapeutic options are non-curative, and women may experience longstanding pain and/or disability. In general, chronic diseases are believed to result from modifiable risk factors, including diet. In this review, we discuss recent data on evidence-based associations between diet and endometriosis and the mechanistic points of action of constituent dietary factors with emphasis on inflammatory events that may contribute to the promotion or inhibition of the disease. Understanding the convergence of diet and endometriosis may lead to the development of clinical strategies to improve the quality of life for symptomatic women.

Oestrogen, progesterone and stem cells: the discordant trio in endometriosis?

Oestrogen–progesterone signalling is highly versatile and critical for the maintenance of healthy endometrium in humans. The genomic and nongenomic signalling cascades initiated by these hormones in differentiated cells of endometrium have been the primary focus of research since 1920s. However, last decade of research has shown a significant role of stem cells in the maintenance of a healthy endometrium and the modulatory effects of hormones on these cells. Endometriosis, the growth of endometrium outside the uterus, is very common in infertile patients and the elusiveness in understanding of disease pathology causes hindrance in selection of treatment approaches to enhance fertility. In endometriosis, the stem cells are dysfunctional as it can confer progesterone resistance to their progenies resulting in disharmony of hormonal orchestration of endometrial homeostasis. The bidirectional communication between stem cell signalling pathways and oestrogen–progesterone signalling is found to be disrupted in endometriosis though it is not clear which precedes the other. In this paper, we review the intricate connection between hormones, stem cells and the cross-talks in their signalling cascades in normal endometrium and discuss how this is deregulated in endometriosis. Re-examination of the oestrogen–progesterone dependency of endometrium with a focus on stem cells is imperative to delineate infertility associated with endometriosis and thereby aid in designing better treatment modalities.

KRAS Activation and over-expression of SIRT1/BCL6 Contributes to the Pathogenesis of Endometriosis and Progesterone Resistance

Endometriosis is an inflammatory condition that is associated with progesterone resistance and cell proliferation, resulting in pain, infertility and pregnancy loss. We previously demonstrated phosphorylation of STAT3 in eutopic endometrium of infertile women with this disorder leading to over-expression of the oncogene BCL6 and stabilization of hypoxia-induced factor 1 alpha (HIF-1α). Here we report coordinated activation of KRAS and over-expression of Sirtuin 1 (SIRT1), a histone deacetylase and gene silencer, in the eutopic endometrium from women with endometriosis throughout the menstrual cycle. The mice with conditional activation of KRAS in the PGR positive cells reveal an increase of SIRT1 expression in the endometrium compared to control mice. The expression of progesterone receptor target genes including the Indian Hedgehog pathway genes are significantly down-regulated in the mutant mice. SIRT1 co-localizes with BCL6 in the nuclei of affected individuals and both proteins bind to and suppress the promoter of GLI1, a critical mediator of progesterone action in the Indian Hedgehog pathway, by ChIP analysis. In eutopic endometrium, GLI1 expression is reduced in women with endometriosis. Together, these data suggest that KRAS, SIRT1 and BCL6 are coordinately over-expressed in eutopic endometrium of women with endometriosis and likely participate in the pathogenesis of endometriosis.

An integrative transcriptomic analysis reveals bisphenol A exposure-induced dysregulation of microRNA expression in human endometrial cells

Bisphenol A (BPA) are commonly used in the manufacture of polycarbonate plastics. Higher BPA exposure levels have been found in patients with endometrial hyperplasia that is one of risk factors of endometrial cancer (EC). Aberrant microRNAs (miRNAs) regulation has been observed in the development of cancer. Thus, this study investigated whether BPA exposure can disrupt miRNA regulation and its gene expression regarding to EC carcinogenic progress. Microarray experiments of miRNA and mRNA were performed in human endometrial cancer RL95-2 cells with treatment of low-to-moderate (10, 10³ and 10⁵nM) BPA to explore the aberrant genes corresponding to human EC progression. According to the analysis of KEGG pathway and Cytoscape gene network, this study identified that BPA exposure reduced miR-149 expression to down-regulate DNA repair gene ARF6 (ADP-ribosylation factor 6) and tumor protein p53 (TP53), and up-regulate CCNE2 (cyclin E2) potentially to interrupt cell cycle. BPA also increased miR-107 to suppress hedgehog signaling factors, suppressor of fused homolog (SUFU) and GLI family zinc finger 3 (GLI3) to activate hedgehog signaling for cell proliferation underlying carcinogenesis. Furthermore, the BPA-induced cell proliferation was attenuated by transfection with miR-149 mimic and miR-107 inhibitor. These findings provided an insight into potential epigenetic mechanism of BPA exposure on the risk of endometrial carcinogenesis.

Progesterone Alleviates Endometriosis via Inhibition of Uterine Cell Proliferation, Inflammation and Angiogenesis in an Immunocompetent Mouse Model

Endometriosis, defined as growth of the endometrial cells outside the uterus, is an inflammatory disorder that is associated with chronic pelvic pain and infertility in women of childbearing age. Although the estrogen-dependence of endometriosis is well known, the role of progesterone in development of this disease remains poorly understood. In this study, we developed a disease model in which endometriosis was induced in the peritoneal cavities of immunocompetent female mice, and maintained with exogenous estrogen. The endometriosis-like lesions that were identified at a variety of ectopic locations exhibited abundant blood supply and extensive adhesions. Histological examination revealed that these lesions had a well-organized endometrial architecture and fibrotic response, resembling those recovered from clinical patients. In addition, an extensive proliferation, inflammatory response, and loss of estrogen receptor alpha (ERα) and progesterone receptor (PR) expression were also observed in these lesions. Interestingly, administration of progesterone before, but not after, lesion induction suppressed lesion expansion and maintained ERα and PR expressions. These progesterone-pretreated lesions exhibited attenuation in KI67, CD31, and pro-inflammatory cytokine expression as well as macrophage infiltration, indicating that progesterone ameliorates endometriosis progression by inhibiting cell proliferation, inflammation and neovascularization. Our studies further showed that suppression of global DNA methylation by application of DNA methyltransferase inhibitor to female mice bearing ectopic lesions restrained lesion expansion and restored ERα and PR expression in eutopic endometrium and ectopic lesions. These results indicate that epigenetic regulation of target gene expression via DNA methylation contributes, at least in part, to progesterone resistance in endometriosis.

Metabolic history impacts mammary tumor epithelial hierarchy and early drug response in mice

The emerging links between breast cancer and metabolic dysfunctions brought forth by the obesity pandemic predict a disproportionate early disease onset in successive generations. Moreover, sensitivity to chemotherapeutic agents may be influenced by the patient's metabolic status that affects the disease outcome. Maternal metabolic stress as a determinant of drug response in progeny is not well defined. Here, we evaluated mammary tumor response to doxorubicin in female mouse mammary tumor virus-Wnt1 transgenic offspring exposed to a metabolically compromised environment imposed by maternal high-fat diet. Control progeny were from dams consuming diets with regular fat content. Maternal high-fat diet exposure increased tumor incidence and reduced tumor latency but did not affect tumor volume response to doxorubicin, compared with control diet exposure. However, doxorubicin-treated tumors from high-fat-diet-exposed offspring demonstrated higher proliferation status (Ki-67), mammary stem cell-associated gene expression (Notch1, Aldh1) and basal stem cell-like (CD29(hi)CD24(+)) epithelial subpopulation frequencies, than tumors from control diet progeny. Notably, all epithelial subpopulations (CD29(hi)CD24(+), CD29(lo)CD24(+), CD29(hi)CD24(+)Thy1(+)) in tumors from high-fat-diet-exposed offspring were refractory to doxorubicin. Further, sera from high-fat-diet-exposed offspring promoted sphere formation of mouse mammary tumor epithelial cells and of human MCF7 cells. Untargeted metabolomics analyses identified higher levels of kynurenine and 2-hydroxyglutarate in plasma of high-fat diet than control diet offspring. Kynurenine/doxorubicin co-treatment of MCF7 cells enhanced the ability to form mammosphere and decreased apoptosis, relative to doxorubicin-only-treated cells. Maternal metabolic dysfunctions during pregnancy and lactation may be targeted to reduce breast cancer risk and improve early drug response in progeny, and may inform clinical management of disease.

Reversal of fortune: estrogen receptor-β in endometriosis

Enhanced inflammation and reduced apoptosis sustain the growth of endometriotic lesions. Alterations in the expression of estrogen receptor-alpha (ERα) and estrogen receptor-beta (ERβ) accompany the conversion of resident endometrial cells within the normal uterine environment to ectopic lesions located in extrauterine sites. Recent studies highlighted in this focused review linked ERβ to dysregulation of apoptotic and inflammatory networks involving novel interacting partners in endometriosis. The elucidation of these nongenomic actions of ERβ using human cells and mouse models is an important step in understanding key regulatory pathways that are disrupted leading to disease establishment and progression.

High-Fat Diet Promotion of Endometriosis in an Immunocompetent Mouse Model is Associated With Altered Peripheral and Ectopic Lesion Redox and Inflammatory Status

Endometriosis is a benign gynecological condition that causes considerable morbidity due to associated infertility, debilitating pelvic pain and inflammatory dysfunctions. Diet is a highly modifiable risk factor for many chronic diseases, but its contribution to endometriosis has not been extensively investigated, due partly to the paradoxical inverse association between obesity and disease incidence. Nevertheless, chronic exposure to dietary high-fat intake has been linked to greater systemic inflammation and oxidative stress, both features of women with endometriosis. Here, we evaluated the effects of a high-fat diet (HFD) (45% fat kcal) on endometriosis progression using an immunocompetent mouse model where ectopic lesion incidence was induced in wild-type recipients by ip administration of endometrial fragments from transcription factor Krüppel-like factor 9-null donor mice. We show that HFD significantly increased ectopic lesion numbers in recipient mice with no significant weight gain and modifications in systemic ovarian steroid hormone and insulin levels, relative to control diet-fed (17% fat kcal) mice. HFD promotion of lesion establishment was associated with reductions in stromal estrogen receptor 1 isoform and progesterone receptor expression, increased F4/80-positive macrophage infiltration, higher stromal but not glandular epithelial proliferation, and enhanced expression of proinflammatory and prooxidative stress pathway genes. Lesion-bearing HFD-fed mice also displayed higher peritoneal fluid TNFα and elevated local and systemic redox status than control diet-fed counterparts. Our results suggest that HFD intake exacerbates endometriosis outcome in the absence of ovarian dysfunction and insulin resistance in mice and warrants further consideration with respect to clinical management of endometriosis progression and recurrence in nonobese patients.

Multiple Beneficial Roles of Repressor of Estrogen Receptor Activity (REA) in Suppressing the Progression of Endometriosis

Endometriosis is an estrogen-dependent, inflammation-driven gynecologic disorder in which endometrial tissue creates inflammatory lesions at extrauterine sites, leading to pelvic pain and impaired fertility. Although dysregulated estrogen receptor (ER) signaling has been implicated, understanding of this disease is incomplete and current therapies are of limited benefit. Using an immunocompetent syngeneic murine model, we used combinations of donor uterine tissue and/or recipient host mice with partial genetic deletion of the ER coregulator, repressor of ER activity (REA) (also known as prohibitin 2), to investigate roles of REA in the contributions of donor uterine tissue and host cell influences on endometriosis establishment and progression. Ectopic lesions derived from donor tissue with half the wild-type gene dosage of REA (REA(+/-)) grown in REA(+/-) hosts displayed enhanced proliferation, vascularization, and markedly increased neuron innervation and inflammatory responses, including elevated cytokine production, nuclear factor kappa B activation, cyclooxygenase-2 expression, and immune cell infiltration. Although lesion progression was greatest when REA was reduced in both donor tissue and host animals, other donor/host combinations indicated that distinct stimulatory inputs were derived from ectopic tissue (proliferative signals) and host cells (inflammatory signals). Importantly, depletion of REA in primary human endometriotic stromal cells led to elevated proliferation and expression of cell cycle regulators. Notably, REA was significantly lower in human endometriotic tissue versus normal human endometrium. Thus, REA modulates cross talk among multiple cell types in the uterine tissue and host background, serving as a brake on the estradiol-ER axis and restraining multiple aspects that contribute to the pathologic progression of endometriosis.

ARID1A Is Essential for Endometrial Function during Early Pregnancy

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

Krüppel-like factor 12 is a novel negative regulator of forkhead box O1 expression: a potential role in impaired decidualization

BACKGROUND

Decidualization is a prerequisite for successful implantation and the establishment of pregnancy. Krüppel-like factor 12 (KLF12) is a negative regulator of endometrial decidualization in vitro. We investigated whether KLF12 was associated with impaired decidualization under conditions of repeated implantation failure (RIF).

METHODS

Uterine tissues were collected from a mouse model of early pregnancy and artificial decidualization for immunohistochemistry, Western blot and real-time PCR analysis. Reporter gene assays, chromatin immunoprecipitation-PCR and avidin-biotin conjugate DNA precipitation assays were performed to analyze the transcriptional regulation of forkhead box O1 (FOXO1) by KLF12. Furthermore, the protein levels of KLF12 and FOXO1 in patients with RIF were analyzed by Western blot and immunohistochemistry.

RESULTS

KLF12 led to defective implantation and decidualization in the mouse uterine model of early pregnancy and artificial decidualization by directly binding to the FOXO1 promoter region and inhibiting its expression in human endometrial stromal cells. Elevated KLF12 expression was accompanied by decreased FOXO1 expression in the endometria of patients with RIF.

CONCLUSIONS

As a novel regulator, KLF12 predominantly controls uterine endometrial differentiation during early pregnancy and leads to implantation failure.

Krüppel-Like Factor 13 Deficiency in Uterine Endometrial Cells Contributes to Defective Steroid Hormone Receptor Signaling but Not Lesion Establishment in a Mouse Model of Endometriosis

Krüppel-like Factor (KLF) 13 and the closely related KLF9 are members of the Sp/KLF family of transcription factors that have collectively emerged as essential regulators of tissue development, differentiation, proliferation, and programmed cell death. Steroid hormone-responsive tissues express multiple KLFs that are linked to progesterone receptor (PGR) and estrogen receptor (ESR) actions either as integrators or as coregulators. Endometriosis is a chronic disease characterized by progesterone resistance and dysregulated estradiol signaling; nevertheless, distinct KLF members' contributions to endometriosis remain largely undefined. We previously demonstrated promotion of ectopic lesion establishment by Klf9 null endometrium in a mouse model of endometriosis. Here we evaluated whether KLF13 loss of expression in endometrial cells may equally contribute to lesion formation. KLF13 transcript levels were lower in the eutopic endometria of women with versus women without endometriosis at menstrual midsecretory phase. In wild-type (WT) mouse recipients intraperitoneally administered WT or Klf13 null endometrial fragments, lesion incidence did not differ with donor genotype. No differences were noted for lesion volume, number, proliferation status, and apoptotic index as well. Klf13 null lesions displayed reduced total PGR and ESR1 (RNA and immunoreactive protein) and altered expression of several PGR and ESR1 target genes, relative to WT lesions. Unlike for Klf9 null lesions, changes in transcript levels for PGR-A, ESR1, and Notch/Hedgehog-associated pathway components were not observed for Klf13 null lesions. Results demonstrate lack of a causative relationship between endometrial KLF13 deficiency and lesion establishment in mice, and they support the broader participation of multiple signaling pathways, besides those mediated by steroid receptors, in the pathology of endometriosis.

The Krüppel-like factors in female reproductive system pathologies

Female reproductive tract pathologies arise largely from dysregulation of estrogen and progesterone receptor signaling, leading to aberrant cell proliferation, survival, and differentiation. The signaling pathways orchestrated by these nuclear receptors are complex, require the participation of many nuclear proteins serving as key binding partners or targets, and involve a range of paracrine and autocrine regulatory circuits. The members of the Krüppel-like factor (KLF) family of transcription factors are ubiquitously expressed in reproductive tissues and have been increasingly implicated as critical co-regulators and integrators of steroid hormone actions. Herein, we explore the involvement of KLF family members in uterine pathology, describe their currently known molecular mechanisms, and discuss their potential as targets for therapeutic intervention.

Prolonged pregnancy in women is associated with attenuated myometrial expression of progesterone receptor co-regulator Krüppel-like Factor 9

CONTEXT

Late-term pregnancy may lead to maternal and neonatal morbidity and mortality. Mice null for the progesterone receptor co-regulator Krüppel-like Factor 9 (KLF9) exhibit delayed parturition and increased incidence of neonatal deaths.

OBJECTIVE

Our aim is to evaluate the contribution of myometrial KLF9 to human parturition.

DESIGN

Myometrial biopsies were obtained from women with term (>37 to ≤41 wk) and late-term (>41 wk) pregnancies during cesarean delivery and assessed for gene and protein expression. Human myometrial cells transfected with nontargeting or KLF9 small interfering RNAs (siRNA) were treated with the progesterone antagonist RU486 and analyzed for pro-inflammatory chemokine/cytokine gene expression.

SETTING

The study took place in a University-affiliated tertiary care hospital and University research laboratory.

PATIENTS

Term patients (n = 8) were in spontaneous active labor whereas late-term patients (n = 5) were either in or were induced to active labor, prior to elective cesarean delivery.

OUTCOME MEASURES

Steroid hormone receptor, contractility, and inflammation-associated gene expression in myometrial biopsies and in siKLF9-transfected, RU486-treated human myometrial cells was associated with KLF9 expression levels.

RESULTS

Myometrium from women with late-term pregnancy showed lower KLF9, total PGR, and PGR-A/PGR-B isoform expression. Transcript levels of select chemokines/cytokines were up- (CSF3, IL1, IL12A, TGFB2) and down- (CCL3, CCL5, CXCL1, CXCL5, IL15) regulated in late-term relative to term myometrium. Knock-down of KLF9 expression in RU486-treated human myometrial cells modified the expression of PGR and labor-associated cytokines, relative to control siRNA-treated cells.

CONCLUSIONS

Myometrial KLF9 may contribute to the onset of human parturition through its regulation of PGR expression and inflammatory signaling networks.

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

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