Leo F. Doherty

Bisphenol-A exposure in utero leads to epigenetic alterations in the developmental programming of uterine estrogen response

Bisphenol‐A (BPA) is a nonsteroidal estrogen that is ubiquitous in the environment. The homeobox gene Hoxa10 controls uterine organogenesis, and its expression is affected by in utero BPA exposure. We hypothesized that an epigenetic mechanism underlies BPA‐mediated alterations in Hoxa10 expression. We analyzed the expression pattern and methylation profile of Hoxa10 after in utero BPA exposure. Pregnant CD‐1 mice were treated with BPA (5 mg/kg IP) or vehicle control on d 9–16 of pregnancy. Hoxa10 mRNA and protein expression were increased by 25% in the reproductive tract of mice exposed in utero. Bisulfite sequencing revealed that cytosine‐guanine dinucleotide methylation was decreased from 67 to 14% in the promoter and from 71 to 3% in the intron of Hoxa10 after in utero BPA exposure. Decreased DNA methylation led to an increase in binding of ER‐α to the Hoxa10 ERE both in vitro as and in vivo as determined by EMSA and chromatin immunoprecipitation, respectively. Diminished methylation of the ERE‐containing promoter sequence resulted in an increase in ERE‐driven gene expression in reporter assays. We identify altered methylation as a novel mechanism of BPA‐induced altered developmental programming. Permanent epigenetic alteration of ERE sensitivity to estrogen may be a general mechanism through which endocrine disruptors exert their action.—Bromer, J. G., Zhou, Y., Taylor, M. B., Doherty, L., Taylor, H. S.. Bisphenol‐A exposure in utero leads to epigenetic alterations in the developmental programming of uterine estrogen response. FASEBJ. 24, 2273–2280 (2010). www.fasebj.org

In utero exposure to diethylstilbestrol (DES) or bisphenol-A (BPA) increases EZH2 expression in the mammary gland: an epigenetic mechanism linking endocrine disruptors to breast cancer.

Diethylstilbestrol (DES) and bisphenol-A (BPA) are estrogen-like endocrine-disrupting chemicals that induce persistent epigenetic changes in the developing uterus. However, DES exposure in utero is also associated with an increased risk of breast cancer in adult women. Similarly, fetal exposure to BPA induces neoplastic changes in mammary tissue of mice. We hypothesized that epigenetic alterations would precede the increased risk of breast neoplasia after in utero exposure to endocrine disruptors. Enhancer of Zeste Homolog 2 (EZH2) is a histone methyltransferase that has been linked to breast cancer risk and epigenetic regulation of tumorigenesis. We examined the effect of BPA and DES on EZH2 expression and function in MCF-7 cells and in mammary glands of mice exposed in utero. DES and BPA treatment approximated human exposure. EZH2 functional activity was assessed by measuring histone H3 trimethylation. Treatment of MCF-7 cells with DES or BPA led to a 3- and 2-fold increase in EZH2 mRNA expression, respectively (p < 0.05) as well as increased EZH2 protein expression. Mice exposed to DES in utero showed a >2-fold increase in EZH2 expression in adult mammary tissue compared with controls (p < 0.05). EZH2 protein was elevated in mammary tissue of mice exposed to DES or BPA. Histone H3 trimethylation was increased in MCF-7 cells treated with BPA or DES. Similarly, mice exposed to BPA or DES in utero showed increased mammary histone H3 trimethylation. Developmental programming of EZH2 is a novel mechanism by which in utero exposure to endocrine disruptors leads to epigenetic regulation of the mammary gland.

Uterine Fibroids Clinical Manifestations and Contemporary Management

Uterine fibroids (leiomyomata) are extremely common lesions that are associated with detrimental effects including infertility and abnormal uterine bleeding. Fibroids cause molecular changes at the level of endometrium. Abnormal regulation of growth factors and cytokines in fibroid cells may contribute to negative endometrial effects. Understanding of fibroid biology has greatly increased over the last decade. Although the current armamentarium of Food and Drug Administration-approved medical therapies is limited, there are medications approved for use in heavy menstrual bleeding that can be used for the medical management of fibroids. Emergence of the role of growth factors in pathophysiology of fibroids has led researchers to develop novel therapeutics. Despite advances in medical therapies, surgical management remains a mainstay of fibroid treatment. Destruction of fibroids by interventional radiological procedures provides other effective treatments. Further experimental studies and clinical trials are required to determine which therapies will provide the greatest benefits to patients with fibroids.

Regulation of Tryptophan 2,3-Dioxygenase by HOXA10 Enhances Embryo Viability Through Serotonin Signaling

Tryptophan 2,3-dioxygenase (TDO) is expressed in endometrium and catabolizes tryptophan, a precursor in the biosynthesis of serotonin. Tryptophan metabolism is an important mechanism for regulation of serotonin levels. Preimplantation mouse embryos are known to express serotonin receptors, specifically the 5-HT1D and 5-HT7 serotonin receptor subtypes. Here we demonstrate that Hoxa10 regulates endometrial TDO expression and improves embryo viability through increased serotonin production. Transfection of pcDNA-Hoxa10 to the murine uterus increased total TDO expression. In vitro, epithelial cell TDO expression was decreased after transfection with Hoxa10. Decreased glandular TDO in response to HOXA10 may augment serotonin production by increasing tryptophan availability. Conversely, stromal TDO expression increased with constitutive Hoxa10 expression. In mice, epithelial serotonin was increased in response to constitutive expression of Hoxa10. Embryo quality was impaired after treatment with Hoxa10 antisense. Blockade of serotonin receptors 1D and 7 also resulted in impaired embryo development, indicating an essential role for Hoxa10 induction of TDO and subsequent serotonin production in embryo development. Transfection of pcDNA-TDO also decreased the number of T cells in the endometrial stroma. We have shown a novel mechanism by which HOXA10 regulates endometrial TDO expression. In the endometrial stroma, HOXA10 increases TDO mRNA, which may increase tryptophan catabolism, allowing for immune tolerance at the time of embryo implantation. In endometrial glands, HOXA10 decreases TDO mRNA leading to increased serotonin that in turn acts to promote normal embryo development.

Leiomyoma-derived transforming growth factor-β impairs bone morphogenetic protein-2-mediated endometrial receptivity.

OBJECTIVE To determine whether transforming growth factor (TGF)-β3 is a paracrine signal secreted by leiomyoma that inhibits bone morphogenetic protein (BMP)-mediated endometrial receptivity and decidualization. DESIGN Experimental. SETTING Laboratory. PATIENT(S) Women with symptomatic leiomyomas. INTERVENTION(S) Endometrial stromal cells (ESCs) and leiomyoma cells were isolated from surgical specimens. Leiomyoma-conditioned media (LCM) was applied to cultured ESC. The TGF-β was blocked by two approaches: TGF-β pan-specific antibody or transfection with a mutant TGF-β receptor type II. Cells were then treated with recombinant human BMP-2 to assess BMP responsiveness. MAIN OUTCOME MEASURE(S) Expression of BMP receptor types 1A, 1B, 2, as well as endometrial receptivity mediators HOXA10 and leukemia inhibitory factor (LIF). RESULT(S) Enzyme-linked immunosorbent assay showed elevated TGF-β levels in LCM. LCM treatment of ESC reduced expression of BMP receptor types 1B and 2 to approximately 60% of pretreatment levels. Preincubation of LCM with TGF-β neutralizing antibody or mutant TGF receptor, but not respective controls, prevented repression of BMP receptors. HOXA10 and LIF expression was repressed in recombinant human BMP-2 treated, LCM exposed ESC. Pretreatment of LCM with TGF-β antibody or transfection with mutant TGF receptor prevented HOXA10 and LIF repression. CONCLUSION(S) Leiomyoma-derived TGF-β was necessary and sufficient to alter endometrial BMP-2 responsiveness. Blockade of TGF-β prevents repression of BMP-2 receptors and restores BMP-2-stimulated expression of HOXA10 and LIF. Blockade of TGF signaling is a potential strategy to improve infertility and pregnancy loss associated with uterine leiomyoma.

A novel mutation of HOXA13 in a family with hand-foot-genital syndrome and the role of polyalanine expansions in the spectrum of Müllerian fusion anomalies

OBJECTIVE To report a novel mutation found in a family with hand-foot-genital syndrome (HFGS). To characterize the genetic basis of true HFGS versus presence of non-HFGS-related uterovaginal septa. DESIGN Case-control study. SETTING Academic medical center. PATIENT(S) The HFGS patients and family members; women with uterine or uterovaginal septa without other sequelae of HFGS. INTERVENTION(S) Sequence analysis of HOXA13 in members of a family with HFGS (3 affected, 1 unaffected); sequence analysis of HOXA13 in biopsy samples obtained from 17 non-HFGS patients with idiopathic uterine or uterovaginal septa and in 11 normal controls. MAIN OUTCOME MEASURE(S) Presence or absence of mutations of HOXA13. RESULT(S) Affected members of a family with HFGS showed a novel expansion of the third polyalanine tract of HOXA13, inserting 10 alanines in-frame. None of the patients with idiopathic uterovaginal septa displayed mutations of HOXA13. CONCLUSION(S) The cause of uterovaginal septa without hand and foot symptoms differs from true HFGS. When patients present with septa, it is not necessary to subject them to roentgenograms of the distal limbs or to sequence analysis of HOXA13 unless they show clear signs of the other sequelae characteristic of true HFGS.

Abnormal streak gonads in 46,XY complete gonadal dysgenesis

OBJECTIVE To describe the surgical findings in two adolescents with 46,XY complete gonadal dysgenesis. DESIGN Report of two cases. SETTING University teaching hospital. PATIENT(S) Two adolescents with 46,XY complete gonadal dysgenesis who underwent laparoscopic bilateral gonadectomy. INTERVENTION(S) Laparoscopic bilateral gonadectomy. MAIN OUTCOME MEASURE(S) Removal of dysgenetic gonads. RESULT(S) One benign fibrothecoma and one gonadoblastoma were identified upon pathologic evaluation of the streak gonads. CONCLUSION(S) Individuals with 46,XY complete gonadal dysgenesis are at risk for malignant transformation of the dysgenetic gonads. Because the risk of malignancy is approximately 30%, prompt gonadectomy should be performed after diagnosis of 46,XY complete gonadal dysgenesis.