[Show abstract][Hide abstract] ABSTRACT: Context: Endometriosis is one of the most common gynecological diseases in women with a prevalence rate of approximately 10%. Chronic pelvic inflammation has been observed in patients with endometriosis and is associated with disease severity. However, how pelvic inflammation promotes endometriosis progression remains unknown. Objective: To investigate the regulatory network of pro-inflammatory cytokines in endometriosis progression. Design, settings, and patients: Immunostaining of human endometrial (n=21) and endometriotic (n=36) sections, quantitative RT-PCR, Western blotting, chromatin immunoprecipitation (ChIP), and luciferase reporter assays in primary culture human endometrial stromal cells were performed. Autologous transplantation of uterine endometrium from control (COUP-TFII flox/flox) and uterus-specific COUP-TFII knockout mice was performed. Results: Expression of chicken ovalbumin upstream promoter-transcription factor II (COUP-TFII) was significantly reduced in endometriotic stroma. Reduction of COUP-TFII in endometriotic stromal cells was mediated by proinflammatory cytokines including interleukin-1β, tumor necrosis factor-α, and transforming growth factor-β1 via a common effector, microRNA-302a (miR-302a). Treatment with these proinflammatory cytokines increased the expression of miR-302a, which targets the 3'UTR of COUP-TFII to cause its downregulation. Intriguingly, downregulation of COUP-TFII in endometrial stromal cells resulted in de-repression of cyclooxygenase-2 (COX-2). Further investigation demonstrated that COUP-TFII directly binds to COX-2 promoter to inhibit its transcription. Forced expression of COUP-TFII inhibited interleukin-1β-induced COX-2 upregulation while knockdown of COUP-TFII augmented this effect. Conclusion: Since overexpression of COX-2 has been demonstrated to be a master regulator in endometriosis progression, our data demonstrate the critical function of pro-inflammatory cytokines and COUP-TFII regulatory gene network in the progression of endometriosis.
The Journal of Clinical Endocrinology and Metabolism 12/2014; · 6.31 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Endometrial cancer is closely associated with endometrial hyperplasia, unopposed estrogen exposure, and genetic alterations. However, the exact cause of endometrial cancer is still unknown. We previously identified mitogen inducible gene 6 (Mig-6) as an important mediator of progesterone signaling in uterus. Tumor suppressor function of progesterone, acting through Mig-6, coordinates endometrial stromal-epithelial communication. The expression of Mig-6 in these cellular compartments is under tight temporal and endocrine control. Here, the role of Mig-6 in the uterine epithelium was defined using floxed Mig-6 (Mig-6(f/f)) mice crossed to Wnt7a-Cre mice (Wnt7a(cre+) Mig-6(f/f)). Wnt7a(cre+) Mig-6(f/f) mice developed endometrial hyperplasia and estrogen-dependent endometrial cancer. Wnt7a(cre+) Mig-6(f/f) mice significantly increased proliferation in epithelial cells as well as apoptosis in sub-epithelial stroma cells. The expression of NOTCH1 and BIRC3 were increased in epithelial cells of Wnt7a(cre+) Mig-6(f/f) mice whereas PR levels were decreased in stromal cells. Progesterone therapy has been shown to be effective in preventing endometrial cancer as well as controlling growth of the endometrium. However, the effectiveness of progesterone for women with endometrial cancer is less clear. The hyperplasia phenotype of Wnt7a(cre+) Mig-6(f/f) mice was prevented by progesterone treatment while PR(cre+) Mig-6(f/f) mice, ablation of Mig-6 in all compartments of the uterus, did not have any effects. We showed that activation of progesterone signaling in the stroma regulates proliferation and apoptosis via suppression of ERα signaling in epithelium. Thus, epithelial Mig-6 is a critical tumor suppressor involved in progesterone mediated protection against the development of endometrial cancer.
[Show abstract][Hide abstract] ABSTRACT: Nuclear receptors and coregulators orchestrate diverse aspects of biological functions and inappropriate expression of these factors often associates with human diseases. The present study describes a conditional overexpression system consisting of a minigene located at the Rosa26 locus in the genome of mouse embryonic stem (ES) cells. Before activation, the minigene is silent due to a floxed STOP cassette inserted between the promoter and the transgene. Upon cre-mediated excision of the STOP cassette, the minigene constitutively expresses the tagged transgene driven by the ubiquitous CAGGS promoter. Thus, this system can be used to express target gene in any tissue in a spatial and/or temporal manner if respective cre mouse lines are available. Serving as proof of principle, the CAG-S-hCOUP-TFI allele was generated in ES cells and subsequently in mice. This allele was capable of conditionally overexpressing human chicken ovalbumin upstream promoter-transcription factor I (COUP-TFI) in all tissues tested upon activation by cre drivers. This allele was further subjected to address functionality of expressed COUP-TFI and the functional similarity between COUP-TFI and COUP-TFII. Expression of COUP-TFI in COUP-TFII-ablated uterus suppressed aberrant estrogen receptor-alpha activities and rescued implantation and decidualization defects of COUP-TFII mutants, suggesting that COUP-TFI and COUP-TFII are able to functionally compensate for each other in the uterus. A toolbox currently under construction will contain ES cell lines for overexpressing all 48 nuclear receptors and selected 10 coregulators. Upon completion, it will be a very valuable resource for the scientific community. Several ES cells are currently available for distribution.
[Show abstract][Hide abstract] ABSTRACT: Synchrony between embryo competency and uterine receptivity is essential for successful implantation. Mice with ablation of chicken ovalbumin upstream promoter-transcription factor II (COUP-TFII) in the uterus (PR(Cre/+);COUP-TFII(flox/flox)) exhibit implantation defects and increased estrogen receptor (ER)alpha activity in the luminal epithelium, suggesting high ERalpha activity may disrupt the window of uterine receptivity. To determine whether increased ERalpha activity in the PR(Cre/+);COUP-TFII(flox/flox) uterus is the cause of defective implantation, we assessed whether inhibition of ERalpha activity could rescue the PR(Cre/+);COUP-TFII(flox/flox) uterine implantation defect. ICI 182,780 (ICI), a pure ERalpha antagonist, was administered to PR(Cre/+);COUP-TFII(flox/flox) mutant and COUP-TFII(flox/flox) control mice during the receptive period, and the number of implantation sites was examined. COUP-TFII(flox/flox) control mice treated with oil or ICI showed the normal number of implantation sites. As expected, no implantation sites were observed in PR(Cre/+);COUP-TFII(flox/flox) mutant mice treated with oil, consistent with previous observations. In contrast, implantation sites were greatly increased in ICI-treated PR(Cre/+);COUP-TFII(flox/flox) mutant mice, albeit at a reduced number in comparison with the control mice. ICI treatment was also able to restore the expression of Wnt4 and bone morphogenetic protein 2, important for endometrial decidualization in the PR(Cre/+);COUP-TFII(flox/flox) mutant mice. To confirm that the rescue of embryo attachment and decidualization is a consequence of a reduced ERalpha activity upon ICI treatment, we showed a reduction of the expression of ERalpha target genes in PR(Cre/+);COUP-TFII(flox/flox) mutant mice. Because COUP-TFII was also shown in our laboratory to be important for placentation during pregnancy, we asked whether ICI treatment could also rescue the placentation defect to allow full-term pregnancy in these mice. We found that whereas mice were born in COUP-TFII(flox/flox) control mice given ICI, no pups were born in the PR(Cre/+);COUP-TFII(flox/flox) mutant mice, suggesting that the increased ERalpha activity is not the reason for placentation defects. These results demonstrate that during the periimplantation period, COUP-TFII regulates embryo attachment and decidualization through controlling ERalpha activity. However, COUP-TFII expression is still required in the postimplantation period to facilitate placentation.
[Show abstract][Hide abstract] ABSTRACT: Normal endometrial function requires a balance of progesterone (P4) and estrogen (E2) effects. E2 acts to stimulate the proliferation of uterine epithelial cells, while P4 action inhibits E2-mediated proliferation of the epithelium. P4 through its cognate receptor, the P4 receptor (Pgr), has important roles in the establishment and maintenance of pregnancy. In previous studies, we have identified ERBB receptor feedback inhibitor 1 (Errfi1) as a downstream target of Pgr action in the uterus. Herein, we show that Errfi1 mRNA expression was significantly increased in the uterus after Day 2.5 of gestation. Its expression is also induced in the uterus by acute E2 treatment, and this induction is synergistically induced by chronic E2 and P4 treatment. Although it is known that conditional ablation of Errfi1 in the Pgr-positive cells (Errfi1(d/d)) results in infertility, the function of Errfi1 in reproductive biology has remained elusive. Using Errfi1(d/d) mice, we have identified Errfi1 as an important mediator of uterine implantation. Epithelial ESR1 and target genes were significantly increased in the uteri of Errfi1(d/d) mice. Our results identify a new signaling paradigm of steroid hormone regulation in female reproductive biology that adds insight into the underlying dysregulation of hormonal signaling in human reproductive disorders such as endometriosis and endometrial cancer.
Biology of Reproduction 12/2009; 82(4):706-13. · 3.45 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Progesterone and estrogen are critical regulators of uterine receptivity. To facilitate uterine remodeling for embryo attachment, estrogen activity in the uterine epithelia is attenuated by progesterone; however, the molecular mechanism by which this occurs is poorly defined. COUP-TFII (chicken ovalbumin upstream promoter transcription factor II; also known as NR2F2), a member of the nuclear receptor superfamily, is highly expressed in the uterine stroma and its expression is regulated by the progesterone-Indian hedgehog-Patched signaling axis that emanates from the epithelium. To further assess COUP-TFII uterine function, a conditional COUP-TFII knockout mouse was generated. This mutant mouse is infertile due to implantation failure, in which both embryo attachment and uterine decidualization are impaired. Using this animal model, we have identified a novel genetic pathway in which BMP2 lies downstream of COUP-TFII. Epithelial progesterone-induced Indian hedgehog regulates stromal COUP-TFII, which in turn controls BMP2 to allow decidualization to manifest in vivo. Interestingly, enhanced epithelial estrogen activity, which impedes maturation of the receptive uterus, was clearly observed in the absence of stromal-derived COUP-TFII. This finding is consistent with the notion that progesterone exerts its control of implantation through uterine epithelial-stromal cross-talk and reveals that stromal-derived COUP-TFII is an essential mediator of this complex cross-communication pathway. This finding also provides a new signaling paradigm for steroid hormone regulation in female reproductive biology, with attendant implications for furthering our understanding of the molecular mechanisms that underlie dysregulation of hormonal signaling in such human reproductive disorders as endometriosis and endometrial cancer.
[Show abstract][Hide abstract] ABSTRACT: Activating signal cointegrator-2 (ASC-2), a coactivator of multiple transcription factors that include retinoic acid receptor (RAR), associates with histone H3-K4 methyltranferases (H3K4MTs) MLL3 and MLL4 in mixed-lineage leukemia. Here, we show that mice expressing a SET domain mutant of MLL3 share phenotypes with isogenic ASC2+/- mice and that expression and H3-K4 trimethylation of RAR target gene RAR-beta2 are impaired in ASC-2-null mouse embryo fibroblasts (MEFs) or in MEFs expressing siRNAs against both MLL3 and MLL4. We also show that MLL3 and MLL4 are found in distinct ASC-2-containing complexes rather than in a common ASC-2 complex, and they are recruited to RAR-beta2 by ASC-2. In contrast, RAR-beta2 expression is intact in MEFs devoid of menin, a component of MLL1 and MLL2 H3K4MT complexes. These results suggest that ASC-2 confers target gene specificity to MLL3 and MLL4 H3K4MT complexes and that recruitment of H3K4MTs to their target genes generally involves interactions between integral components of H3K4MT complexes and transcription factors.
Proceedings of the National Academy of Sciences 11/2006; 103(42):15392-7. · 9.81 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Insulin-induced gene-1 (Insig-1) and its homolog Insig-2 encode closely related proteins of the endoplasmic reticulum that block proteolytic activation of sterol regulatory element binding proteins, membrane-bound transcription factors that activate synthesis of cholesterol and fatty acids in animal cells. These proteins also restrict lipogenesis in mature adipocytes and block differentiation of preadipocytes. Herein, we identified a novel 1alpha,25-dihydroxyvitamin D3 [1,25-(OH)2D3] response element in the promoter region of Insig-2 gene, which specifically binds to the heterodimer of retinoid X receptor and vitamin D receptor (VDR) and directs VDR-mediated transcriptional activation in a 1,25-(OH)2D3-dependent manner. Interestingly, 1,25-(OH)2D3 is known to directly suppress the expression of peroxisome proliferator-activated receptor gamma2 protein and inhibits adipocyte differentiation of 3T3-L1 preadipocytes and murine bone marrow stromal cells. Consistent with an idea that the antiadipogenic action of 1,25-(OH)2D3 may also involve up-regulation of Insig-2, we found that 1,25-(OH)2D3 transiently but strongly induces Insig-2 expression in 3T3-L1 cells. This novel regulatory circuit may also play important roles in other lipogenic cell types that express VDR, and collectively our results suggest an intriguing, new linkage between 1,25-(OH)2D3 and lipogenesis.