Mouse model for endometriosis is characterized by proliferation and inflammation but not epithelial-to-mesenchymal transition and fibrosis.

Endometriosis is a common disorder of unknown etiology, and non-surgical therapies are still a challenge. To understand the pathogenesis and preclinical testing of drugs for endometriosis, animal models are highly desirous. Herein, we carried out longitudinal characterization of a mouse model for endometriosis where uterine tissue was transplanted onto the intestinal mesentery. During the course of lesion development from day 15 to 60 post-induction, the ectopic endometrium became pale, fluid-filled and the animals developed peritoneal adhesions. Most lesions resembled a well-differentiated type of endometriosis and ~13% of animals had mixed type of lesions. There was extensive stromal compaction in the ectopic tissue. During the progression of endometriosis, there was increased proliferation of epithelial and stromal cells as evident by PCNA staining. Cyp19a1 (aromatase) mRNA was detected in the ectopic lesions on day 15 and 30 post-induction of endometriosis, by day 60 the expression was reduced. As compared to the control endometrium, the mRNA levels of Esr1 progressively reduced while the levels of inflammation associated genes (Esr2, Ifng, Tnf and Il1b) increased in the ectopic lesions. Infiltration of macrophages and polymorphonuclear leucocytes was also observed in the ectopic lesions indicative of inflammation. As compared to control, there was no change in levels of Cytokeratin and E-cadherin in the epithelial cells of ectopic endometrium. We did not observe excessive collagen deposition or α -SMA positive myofibroblasts in the stroma of the ectopic endometrium. Thus, epithelial-to-mesenchymal transition and fibrosis are not detected in the mouse model of endometriosis. Our results show that the mouse model of endometriosis mimics some but not all the features of human endometriosis.

Spatial and temporal changes in the expression of steroid hormone receptors in mouse model of endometriosis.

PURPOSE: Endometriosis is recognized as a steroid hormone-dependent disorder. However, controversies exist regarding the status of the steroid hormone receptor expression in endometriotic tissues. The purpose of this study was to determine the ontogeny of cellular changes in the expression of estrogen receptors (ERα, ERß), G protein-coupled estrogen receptor 1 (GPER1), and progesterone receptors (PRs) in endometriosis using a mouse model. METHODS: We used the autologous uterine tissue transfer mouse model and studied the mRNA and protein expression of ERα, ERß, GPER1, and PR in ectopic lesions at 2, 4, and 8 weeks of induction of endometriosis. RESULT: As compared to endometrium of controls, in the ectopic endometrium, ERα is reduced while ERß was elevated in stromal cells; however, Gper1 and PR levels are reduced in both stromal and epithelial cells in a time-specific manner. There is a high inter-animal variation in the levels of these receptors in ectopic endometrium as compared to controls; the levels also varied by almost 100-fold within the same lesion resulting in "micro-heterogeneity." The expression of all these receptors also deferred between two lesions from the same animal. CONCLUSION: In the endometriotic tissue, there is extensive inter-animal and intra-lesion heterogeneity in the expression of ERα, ERß, GPER1, and PR. These changes are not due to the influence of the peritoneal environment but appear to be tissue intrinsic. We propose that the variable outcomes in hormonal therapy for endometriosis could be possibly due to heterogeneity in the expression of steroid hormone receptors in the ectopic endometrium.

Correction to: Progesterone requires heat shock protein 90 (HSP90) in human sperm to regulate motility and acrosome reaction.

In the original Fig 1, we had inadvertently placed the DAPI channel image of the HSP90α as negative control.

Estrogen is essential but not sufficient to induce endometriosis.

Endometriosis is a common gynaecological disorder of unknown aetiology. Among the several factors, estrogen has been implicated as a causative factor in endometriosis. In the present study using mouse model, we assessed the role of estrogen in the initial implantation and growth of endometrium in ectopic locations. Uterine tissues from green fluorescent protein (GFP) mice were transplanted in to the peritoneum of wild type mice in presence and absence of estrogen. As compared to untreated controls, the implantation of uterine tissue at ectopic locations was higher when estrogen was administered to both host and donor animals. However, this effect was not sustained as lesions regressed within 14 days of treatment. Irrespective of the treatment, peritoneal adipose was the most preferred site of lesion establishment. The lesions did not have typical features of the endometriosis (presence of glands and stroma) even after estrogen treatment and the ectopic tissue underwent regression by apoptosis irrespective of treatment. Since estrogen promotes implantation of endometrial tissue to ectopic locations but failure of these ectopic lesions to grow and sustain even in high estrogenic environment we propose that estrogen is necessary but not sufficient to sustain endometriosis.

Decrease in Expression of HOXA10 in the Decidua After Embryo Implantation Promotes Trophoblast Invasion.

An important step toward successful pregnancy involves invasion of the trophoblast cells into the decidua for placentation. Herein, we show that in the human and baboon decidua HOXA10 expression is downregulated after implantation and that this reduction is most prominent in the decidual cells juxtaposed to the invading placental villi. The supernatants derived from HOXA10-depleted human decidual cells increase the invasiveness of the trophoblast cell lines ACH-3P and JEG3 in vitro; this increase is due to higher expression and activity of matrix metalloproteases (MMPs) and reduced expression of tissue inhibitors of MMPs in both the cell lines. The proinvasive ability of HOXA10-depleted decidual cells is due to increased levels and secretion of leukemia inhibitor factor (LIF) and interleukin (IL)-6. Both these cytokines individually promote invasion of ACH-3P and JEG3 cell by increasing the activities of MMPs and decreasing mRNA levels of TIMPs. Finally, we demonstrate that the supernatants derived from HOXA10-depleted decidual cell-phosphorylated STAT3 (Tyr 705) and knocking down STAT3 in ACH-3P and JEG3 cells restrained the invasion mediated by supernatants derived from HOXA10-depleted decidual cells. These results imply that STAT3 activity is essential and sufficient to promote invasion in response to downregulation of HOXA10 in decidual cells. We propose that downregulation of HOXA10 in the decidual cells promotes the expression of LIF and IL-6, which, in a paracrine manner, activates STAT3 in the trophoblast cells, leading to an increase in MMPs to facilitate invasion.

Progesterone requires heat shock protein 90 (HSP90) in human sperm to regulate motility and acrosome reaction.

PURPOSE: The aims of this paper were to study whether heat shock protein 90 (HSP90) is a regulator of sperm functions and to determine its association with oligoasthenozoospermia. METHODS: The levels of HSP90 in sperm lysates were measured by ELISA. Localization of HSP90 and its isoforms was evaluated by immunofluorescence. Sperm motility and kinetics were assessed by computer-assisted sperm analysis. Acrosome reaction was determined by lectin staining. RESULTS: The levels of HSP90 were lower in oligoasthenozoospermic men and correlated positively with the number of motile spermatozoa. In capacitated human spermatozoa, HSP90α was mostly found in residual nuclear envelope, and the HSP90ß isoform was higher in the flagella. Inhibition of HSP90 by geldanamycin or 17-AAG did not affect basal motility, but suppressed progesterone-mediated forward progressive motility, hyperactivation and acrosome reaction. Progesterone treatment dephosphorylated both HSP90α and HSP90ß at Ser/Thr-Pro residues, but not Tyr residues. CONCLUSION: HSP90 levels are downregulated in oligoasthenozoospermia, and its functional inhibition attenuates progesterone-mediated sperm motility and acrosome reaction.

Progesterone utilizes the PI3K-AKT pathway in human spermatozoa to regulate motility and hyperactivation but not acrosome reaction.

Progesterone is a physiologic regulator of sperm hyperactivation and acrosome reaction and it does so by activating a range of kinases present in the spermatozoa. In the present study, the involvement of the AKT- phosphatidylinositol 3-kinase (PI3K) signaling pathway in mediating progesterone response in human spermatozoa was investigated. In capacitated spermatozoa, progesterone transiently and concentration dependently lead to phosphorylation of AKT at both Thr 308 and Ser 473 in the tail region. This phosphorylation was inhibited by the PI3K inhibitor wortmannin, suggesting that progesterone leads to activation of PI3K-AKT pathway. The activation of AKT in response to progesterone is calcium dependent and the CatSper channel inhibitor mibefradil significantly reduced progesterone mediated AKT phosphorylation. Preincubation of spermatozoa with wortmannin inhibited the progesterone mediated increase in tyrosine phosphorylation and also attenuated the increase in number of motile, progressively motile and hyperactive spermatozoa but not the number of acrosome reacted spermatozoa. These observations imply that progesterone via CatSper activates the PI3K-AKT pathway required for motility and hyperactivation but not for acrosome reaction.