Allison Brudney

Steroid receptor and aromatase expression in baboon endometriotic lesions.

OBJECTIVE To evaluate steroid receptor and aromatase gene expression in endometriotic lesions, and determine the effects of endometriosis on uterine receptivity in a baboon model for endometriosis. DESIGN Prospective study to determine the expression of steroid receptors, and aromatase in ectopic endometriotic lesions and endometrial genes in the eutopic endometrium of baboons with induced endometriosis by reverse transcriptase-polymerase chain reaction (RT-PCR) and immunocytochemistry. SETTING University research laboratory and primate research facility. ANIMAL(S) Normally cycling baboons inoculated intraperitoneally with menstrual endometrium to induce endometriosis. INTERVENTION(S) Endometriotic lesions were resected during laparotomy, and endometrium was obtained by endometrectomy or after hysterectomy. MAIN OUTCOME MEASURE(S) Steroid receptor and aromatase expression by RT-PCR and immunocytochemistry in endometriotic lesions and glycodelin and alpha-smooth muscle actin expression and localization in endometrium after chorionic gonadotropin (CG) stimulation. RESULT(S) This study demonstrated that estrogen receptor-alpha (ERalpha) and progesterone receptor (PR) were expressed in both ectopic and eutopic endometrium between 1 and 10 months after inoculation. In contrast, ERbeta was only expressed in the ectopic endometriotic lesions. Aromatase expression was only evident in lesions obtained 10 months after inoculation. Infusion of CG during the luteal phase failed to induce the expression of glycodelin in the glandular epithelium or alpha-smooth muscle actin (alpha-SMA) in stromal cells in animals with endometriosis as early as 1 and 4 months after inoculation. CONCLUSION(S) The ERbeta expression is selectively up-regulated in the endometriotic lesions at all stages of the disease, whereas aromatase expression is not evident until the disease progresses. However, expression of uterine receptivity markers was down-regulated as early as 1 and 4 months after inoculation.

A Modified Baboon Model for Endometriosis

Abstract: Endometriosis is one of the most common causes of infertility and chronic pelvic pain and affects 1 in 10 women in the reproductive‐age group. Although existence of this disease has been known for over 100 years, our current knowledge of its pathogenesis, the pathophysiology of related infertility, and its spontaneous evolution is limited. Several reasons contribute to our lack of knowledge, the most critical being the difficulty in carrying out objective long‐term studies in women. Thus, we and others have developed the baboon as an appropriate nonhuman primate to study the etiology of this disease. We suggested that endometriosis develops in two distinct phases. Phase I is invasive and dependent on ovarian steroids. Phase II, which is the active phase of the disease, is characterized by endogenous estrogen biosynthesis. Following inoculation with menstrual endometrial tissues in two consecutive menstrual cycles, baboons develop lesions that are similar to those seen in humans. Laparoscopy at 1, 4, and 10 months revealed a preponderance of red raised nodules at the first month, while both red lesions and reddish‐blue proliferative endometriotic lesions were evident at 4 and 10 months. The presence of glandular tissue and stromal fibroblasts in these lesions was confirmed by histology. Lesions obtained at 1 and 4 months expressed estrogen receptor β (ERβ), matrix metalloproteinase‐7 (MMP‐7), and vascular endothelial growth factor (VEGF) predominantly. However, aromatase expression was only readily evident at 10 months, although some lesions obtained at 4 months expressed low levels of aromatase. Therefore, our preliminary data suggest that endometriosis can be artificially induced in baboons, and the role of exogenous and endogenous estradiol in proliferation, angiogenesis, and immune modulations can now be evaluated in a potentially systemic manner.

Signal Transduction Pathways Activated by Chorionic Gonadotropin in the Primate Endometrial Epithelial Cells

Abstract Successful implantation requires synergism between the developing embryo and the receptive endometrium. In the baboon, infusion of chorionic gonadotropin (CG) modulates both morphology and physiology of the epithelial and stromal cells of the receptive endometrium. This study explored the signal transduction pathways activated by CG in endometrial epithelial cells from baboon (BE) and human (HES). Incubations of BE and HES cells with CG did not significantly alter adenylyl cyclase activity or increase intracellular cAMP when compared with Chinese hamster ovarian cells stably transfected with the full-length human CG/luteinizing hormone (LH) receptor (CHO-LH cells). However, in BE and HES cells, CG induced the phosphorylation of several proteins, among them, extracellular signal-regulated protein kinases 1 and 2 (ERK 1/2). Phosphorylation of ERK 1/2 in uterine epithelial cells was protein kinase A (PKA) independent. This novel signaling pathway is functional because, in response to CG stimulation, prostaglandin E2 (PGE2) was released into the media and increased significantly 2 h following CG stimulation. CG-stimulated PGE2 synthesis in epithelial cells was inhibited by a specific mitogen-activated protein kinase (MEK 1/2) inhibitor, PD 98059. In conclusion, immediate signal transduction pathways induced by CG in endometrial epithelial cells are cAMP independent and stimulate phosphorylation of ERK 1/2 via a MEK 1/2 pathway, leading to an increase in PGE2 release as the possible result of cyclooxygenase-2 activation.

The Altered Distribution of the Steroid Hormone Receptors and the Chaperone Immunophilin FKBP52 in a Baboon Model of Endometriosis Is Associated With Progesterone Resistance During the Window of Uterine Receptivity

This study examines the distribution of estrogen receptors (ESR), progesterone receptors (Pgr), and the chaperone immunophilin FKBP52 in the eutopic endometrium in a baboon model of endometriosis during the window of receptivity to determine if their aberrant distribution contributes to reduced fecundity. Endometriosis was induced by inoculation of menstrual endometrium into the peritoneal cavity. Eutopic endometrium was collected at 3, 6, 9, 12, and 15 months postinoculation. Western blot (WB) and immunohistochemical analyses were performed. Isolated endometrial stromal cells were cultured in the presence or absence of steroid hormones. In animals with endometriosis, ESR-1 (ER-α) decreased in endometrial stromal cells, while ESR-2 (ER-β) was reduced in both glandular epithelial (GE) and stromal cells. Immunoreactive total Pgr was markedly diminished in the GE, which was confirmed by WB analysis. Furthermore, treatment of isolated stromal cells from baboons with endometriosis with hormones did not increase levels of PRA or PRB as in control baboons. FKBP52 was also reduced in the eutopic endometrium of baboons with endometriosis. Endometriosis results in an aberrant distribution of ESR-1, ESR-2, Pgr, and FKBP52 in the eutopic endometrium. The authors propose that a dysregulation in the paracrine signaling between the endometrial stromal and GE cells reduces the responsiveness of Pgr, creating an endometrial environment that is unsuitable for implantation.

Modulation of the Action of Chorionic Gonadotropin in the Baboon (Papio anubis) Uterus by a Progesterone Receptor Antagonist (ZK 137.316)

Abstract Signals from the developing mammalian blastocyst rescue the corpus luteum (CL) and modulate the uterine environment in preparation for implantation and early pregnancy. Our previous studies demonstrated that both short- and long-term administration of chorionic gonadotropin (CG) markedly alters the morphology and the biochemical activity of the receptive endometrium. Because the effects of CG were superimposed on a progesterone-primed endometrium, this study was undertaken to determine if the inhibition of progesterone action by progesterone receptor antagonists (PRa) in intact and ovariectomized baboons would alter the action of CG on the endometrium at the time of uterine receptivity. In the short-term hCG-treated baboons, the PRa reduced the epithelial plaque reaction, completely inhibited α-smooth muscle actin (αSMA) expression in stromal fibroblasts, and induced the reappearance of the progesterone (PR) and estrogen (ERα) receptors in epithelial cells. However, this treatment protocol had no effect on the expression of glycodelin in the glandular epithelium. In contrast, glycodelin expression in addition to αSMA was suppressed in the ovariectomized animals. In the long-term hCG-treated baboons, the PRa had a similar effect on both αSMA, PR, and ER. In addition, this treatment also resulted in an inhibition of glycodelin expression in the glandular epithelium. These results indicate that blocking the action of progesterone on the endometrium even for a short period of time has a profound effect on the hCG-induced response in stromal fibroblasts. In contrast, for the diminution of glandular epithelial function in the presence of an ovary requires prolonged inhibition of progesterone action, suggesting a potential paracrine effect on the endometrium from the CL in response to hCG.

Progesterone Induces Calcitonin Expression in the Baboon Endometrium Within the Window of Uterine Receptivity

Abstract The mammalian uterus can accept a developing blastocyst for implantation only within a limited period of time, termed the receptive phase. Our previous studies showed that the expression of calcitonin, a peptide hormone that regulates calcium homeostasis, is induced by progesterone immediately preceding implantation, and is required for the generation of a receptive rat uterus. In this study, we investigated the expression and hormonal regulation of calcitonin in the baboon endometrium during the window of implantation. We monitored the spatio-temporal expression of calcitonin at various days of the menstrual cycle. Reverse transcriptase-polymerase chain reaction analysis of the baboon endometrium on Days 9 and 10 postovulation revealed stage-specific expression of calcitonin mRNA, which overlapped with the window of uterine receptivity. Immunocytochemical analysis of baboon endometrium sections localized calcitonin expression in the glandular epithelial and stromal cells. Treatment of animals with the antiprogestin ZK 137.316 dramatically reduced calcitonin expression, indicating that calcitonin expression in the baboon endometrium is under progesterone regulation. Collectively, these findings strongly suggest that the appearance of calcitonin in progesterone-dominated endometrium is conserved among species and may serve as a marker of uterine receptivity for embryo implantation.

The altered distribution of the steroid hormone receptors and the chaperone immunophilin FKBP52 in a baboon model of endometriosis is associated with progesterone resistance during the window of uterine receptivity ((Reproductive Sciences) 390-394)

In the article “The Altered Distribution of the Steroid Hormone Receptors and the Chaperone Immunophilin FKBP52 in a Baboon Model of Endometriosis Is Associated With Progesterone Resistance During the Window of Uterine Receptivity” by Kevin S. Jackson, PhD, Allison Brudney, BS, Julie M. Hastings, PhD, Patricia A. Mavrogianis, MS, J. Julie Kim, PhD, and Asgerally T. Fazleabas, PhD, the following figures should have appeared in color