Growth differentiation factor myostatin regulates epithelial-mesenchymal transition genes and enhances invasion by increasing serine protease inhibitors E1 and E2 in human trophoblast cells

Placental insufficiency disorders, including preeclampsia and intrauterine growth restriction, are major obstetric complications that can have devastating effects on both the mother and the fetus. These syndromes have underlying poor placental trophoblast cell invasion into uterine tissues. Placental invasion is controlled by many hormones and growth factors. Myostatin (MSTN) is a transforming growth factor-β superfamily member recognized for its important role in muscle growth control. MSTN has also been shown to be secreted and functioning in the placenta, and its serum and/or placental levels were found to be upregulated in preeclampsia and intrauterine growth restriction. Considering that the mechanistic role of MSTN in placentation remains poorly understood, we hypothesized that MSTN uses ALK4/5-SMAD2/3/4 signaling to increase human trophoblast invasion through a group of epithelial-mesenchymal transition genes including SERPINE2, PAI-1, and SOX4. mRNA sequencing of control and MSTN-treated primary human trophoblast cells (n = 5) yielded a total of 610 differentially expressed genes (false discovery rate <0.05) of which 380 genes were upregulated and 230 were downregulated. These differentially expressed genes were highly enriched in epithelial-mesenchymal transition genes, and a subset including SERPINE2, PAI-1, and SOX4 was investigated for its role in MSTN-induced trophoblast cell invasion. We found that MSTN induced upregulation of SERPINE2 via ALK4/5-SMAD2/3/4 signaling; however, SMAD2 was not involved in MSTN-induced PAI-1 upregulation. SOX4 was involved in MSTN-induced upregulation of SERPINE2, but not PAI-1. Collectively, this study discovers novel molecular mechanisms of MSTN-induced human trophoblast cell invasion and provides insight into the functional consequences of its dysregulation in placental insufficiency disorders.

Interleukin-1β and plasminogen activating system members in endometriotic stromal cell migration/invasion

OBJECTIVE

To study the role of interleukin (IL)-1β and the plasminogen activating (PA) system members in endometriotic stromal cell (ESC) migration/invasion.

DESIGN

Primary cultures of ESCs.

SETTING

Tertiary referral center for endometriosis and pelvic pain.

PATIENT(S)

Patients with surgically excised endometriosis.

INTERVENTION(S)

Interleukin-1β stimulation of primary cultures of ESCs and knockdown of the PA system members urokinase plasminogen activator (uPA), uPA receptor, and plasminogen activator inhibitor-1 (PAI-1).

MAIN OUTCOME MEASURE(S)

Invasion/migration assays.

RESULT(S)

In primary cultures, IL-1β-stimulated ESC production of the PA system members uPA, uPA receptor, and PAI-1. Interleukin-1β also enhanced ESC migration and invasion, and these effects were inhibited by the IL-1 receptor-1 antagonist anakinra. Knockdown of each of the 3 PA system members also inhibited ESC migration and invasion. Knockdown of these PA system members further attenuated the impact of IL-1β on migration and invasion, suggesting that they mediated the promigration and proinvasion effects of IL-1β. To supplement the cell culture work, immunohistochemistry was performed on tissue sections of endometriotic epithelium/stroma: uPA, PAI-1, and IL-1β histoscores were not found to be correlated with each other.

CONCLUSION(S)

In primary cultures of ESCs, IL-1β induces migration and invasion, which is mediated by PA system members and inhibited by the drug anakinra. However, the immunohistochemistry expression of IL-1β, urokinase plasminogen inhibitor-1, and PAI-1 were not correlated, suggesting other regulatory mechanisms for PA system members. Inhibition of IL-1β (e.g., with anakinra) may have potential as a novel treatment approach for the migration/invasion of endometriosis.

Characterization of the roles of amphiregulin and transforming growth factor β1 in microvasculature-like formation in human granulosa-lutein cells

Vascular endothelial-cadherin (VE-cadherin) is an essential component that regulates angiogenesis during corpus luteum formation. Amphiregulin (AREG) and transforming growth factor β1 (TGF-β1) are two intrafollicular factors that possess opposite functions in directing corpus luteum development and progesterone synthesis in human granulosa-lutein (hGL) cells. However, whether AREG or TGF-β1 regulates the VE-cadherin expression and subsequent angiogenesis in the human corpus luteum remains to be elucidated. Results showed that hGL cells cultured on Matrigel spontaneously formed capillary-like and sprout-like microvascular networks. Results of specific inhibitor treatment and small interfering RNA-mediated knockdown revealed that AREG promoteed microvascular-like formation in hGL cells by upregulating the VE-cadherin expression mediated by the epidermal growth factor receptor (EGFR)-extracellular signal-regulated kinase1/2 (ERK1/2) signaling pathway. However, TGF-β1 suppressed microvascular-like formation in hGL cells by downregulating VE-cadherin expression mediated by the activin receptor-like kinase (ALK)5-Sma- and Mad-related protein (SMAD)2/3/4 signaling pathway. Collectively, this study provides important insights into the underlying molecular mechanisms by which TGF-β1 and AREG differentially regulate corpus luteum formation in human ovaries.

Activin a promotes hyaluronan production and upregulates versican expression in human granulosa cells via the ALK4-SMAD2/3-SMAD4 signaling pathway

Hyaluronan is a structural component of the expanded cumulus matrix, and hyaluronan synthase 2 (HAS2) is the major enzyme for the synthesis of hyaluronan in humans. Versican cross-links the hyaluronan-rich matrix to cumulus cells and is critical for successful ovulation. Activin A is a critical intrafollicular regulator of ovarian function. Although activin A has been shown to promote cumulus matrix expansion in mice, the functional role of activin A in the regulation of cumulus expansion in the human ovary remains to be elucidated. Using primary and immortalized human granulosa-lutein (hGL) cells as study models, we provide the first data showing that activin A increased the production of hyaluronan by upregulating the expression of HAS2 in these cells. Additionally, activin A also promoted the expression of the hyaluronan-binding protein versican. Moreover, using inhibitor- and siRNA-mediated inhibition approaches, we found that these stimulatory effects of activin A are most likely mediated through the type I receptor ALK4-mediated SMAD2/SMAD3-SMAD4 signaling pathway. Notably, the ChIP analyses demonstrated that SMAD4 could bind to human HAS2 and VERSICAN promoters. The results obtained from this in vitro study suggest that locally produced activin A plays a functional role in the regulation of hyaluronan production and stabilization in hGL cells.

Myostatin increases human trophoblast cell invasion by upregulating N-cadherin via SMAD2/3-SMAD4 Signaling

Placental insufficiency disorders are major obstetric complications that share a common phenomenon of poor placental trophoblast cell invasion and remodeling of uterine tissues. Myostatin is a transforming growth factor (TGF)-β superfamily member well-known for its important role in muscle growth control. Myostatin is also produced in the placenta and has been shown to regulate some trophoblast functions. However, its roles in placental development are still poorly understood. In this study, we tested the hypothesis that myostatin increases trophoblast cell invasion by upregulating N-cadherin via SMAD2/3-SMAD4 signaling. Primary and immortalized (HTR8/SVneo) trophoblast cells were used as study models. Matrigel-coated transwell invasion assays were used to study the effects of recombinant human myostatin on trophoblast cell invasion. RT-qPCR and Western blot were used to measure myostatin effects on N-cadherin mRNA and protein levels, respectively. Small inhibitor molecules as well as siRNA-mediated knockdown were used to block myostatin receptor and downstream signaling, respectively. Data were analyzed either by unpaired Student T test or one-way ANOVA followed by Newman Keuls test for multiple group comparisons. Myostatin significantly increased primary and HTR8/SVneo trophoblast cell invasion. Moreover, myostatin upregulated N-cadherin mRNA and protein levels in a time dependent manner in both study models. These effects were blocked by inhibition of TGF-β type I receptors as well as siRNA-mediated knockdown of SMAD2/3 combined or common SMAD4. Importantly, myostatin-induced trophoblast cell invasion was abolished by knockdown of N-cadherin, SMAD2/3 or SMAD4. Myostatin may increase human trophoblast cell invasion by upregulating N-cadherin via SMAD2/3-SMAD4 signaling.

Dysregulated BMP2 in the Placenta May Contribute to Early-Onset Preeclampsia by Regulating Human Trophoblast Expression of Extracellular Matrix and Adhesion Molecules

Many pregnancy disorders, including early-onset preeclampsia (EOPE), are associated with defects in placental trophoblast cell invasion and differentiation during early placental development. Bone morphogenetic protein 2 (BMP2) belongs to the TGF-β superfamily and controls various physiological and developmental processes. However, the expression of BMP2 in the placenta and underlying molecular mechanisms of how BMP2 regulates trophoblast function remain unclear. In this study, we analyzed several publicly available microarray and RNA-seq datasets and revealed differences in expression of TGF-β superfamily members between gestational age-matched non-preeclamptic control and EOPE placentas. Importantly, BMP2 levels were significantly reduced in EOPE placentas compared with controls, and RNAscope in situ hybridization further demonstrated BMP2 expression was disrupted in EOPE placental villi. To explore the molecular mechanisms of BMP2-regulated early trophoblast differentiation, we examined BMP2 expression in first-trimester human placenta and found it to be localized to all subtypes of trophoblasts and the decidua. RNA-seq analysis on control and BMP2-treated primary human trophoblast cells identified 431 differentially expressed genes, including several canonical TGF-β/BMP signaling targets (BAMBI, ID1, INHBA, IGFBP3). Gene ontology annotations revealed that differentially expressed genes were involved in cell adhesion and extracellular matrix organization. Furthermore, we identified adhesion molecule with IgG-like domain 2 (AMIGO2) as a novel target for BMP2 that contributed to BMP2-induced trophoblast invasion and endothelial-like tube formation. Overall, our findings provide insight into the molecular processes controlled by BMP2 during early placental development that may contribute to the pathogenesis of EOPE.

Transcription factor SOX4 facilitates BMP2-regulated gene expression during invasive trophoblast differentiation

The interplay between growth factors, signaling pathways and transcription factors during placental development is key to controlling trophoblast differentiation. Bone morphogenetic protein 2 (BMP2) has been implicated in trophoblast invasion and spiral artery remodeling during early placental development. However, the molecular mechanisms by which these are accomplished have not been fully elucidated, particularly for transcriptional regulation of key transcription factors. Here, we identified SOX4 as a direct target gene induced by BMP2 in first-trimester placental trophoblasts. Analysis of single-cell RNA-seq data from first-trimester placentas and decidua tissues revealed that SOX4 expression is mainly localized in extravillous trophoblast and decidual stromal cells. Moreover, gain- and loss-of-function approaches demonstrated that SOX4 exerts a pro-invasive role in human trophoblasts, and this effect contributes to BMP2-enhanced trophoblast invasion. Importantly, we found that SOX4 was required for BMP2-induced regulation of a subset of genes associated with cell migration and extracellular matrix organization. We also show that SOX4-dependent regulation of the BMP2 target SERPINE2 occurs via binding of SOX4 to regulatory elements such as enhancers, thereby promoting BMP2-induced trophoblast invasion. In conclusion, these findings uncover a novel mechanism involving SOX4 that shapes the BMP2-regulated transcriptional network during invasive trophoblast development.

GDF8 Promotes the Cell Invasiveness in Human Trophoblasts by Upregulating the Expression of Follistatin-Like 3 Through the ALK5-SMAD2/3 Signaling Pathway

Growth differentiation factor 8 (GDF8) and its antagonist follistatin-like 3 (FSTL3) are expressed in the placenta during early pregnancy. These two factors may have a role to play in the regulation of normal placentation. However, whether GDF8 can regulate the expression of FSTL3 in human trophoblasts remains to be elucidated. In this study, we aimed to investigate the effects of GDF8 on the expression of FSTL3 and the underlying molecular mechanisms using human trophoblasts as a study model. Our results showed that GDF8 significantly upregulates the expression and production of FSTL3, which further promotes cell invasiveness in immortalized extravillous cytotrophoblast cells and primary extravillous cytotrophoblast cells obtained from human first-trimester placentae. Additionally, using an siRNA-mediated knockdown approach, we found that this regulatory effect is most likely mediated by the ALK5-Sma- and Mad-related protein (SMAD)2/3-induced signaling pathway. These findings deepen our understanding of the functional roles of GDF8 and FSTL3 in the regulation of cell invasiveness of trophoblasts.

NPFF increases fusogenic proteins syncytin 1 and syncytin 2 via GCM1 in first trimester primary human cytotrophoblast cells

Neuropeptide FF (NPFF) is well-known for its roles in the central nervous system. Despite studies demonstrating that NPFF receptor 2 (NPFFR2) mRNA is highest in placenta, nothing is known about NPFF-NPFFR2 functions in placental development. Here, we investigated the effects of NPFF-NPFFR2 on expression of syncytial [human chorionic gonadotropin (hCG) β] and fusogenic [syncytin 1, syncytin 2, and glial cells missing 1 (GCM1)] genes in first trimester primary human cytotrophoblast cells. By analyzing two publicly available microarray data sets, we found that NPFF is consistently expressed throughout gestation whereas NPFFR2 increases in first trimester and is elevated in placenta samples from women with preeclampsia. Immunohistochemistry showed that NPFFR2, syncytin 1/2, and GCM1 each displayed unique patterns of expression among different trophoblast populations in first trimester placenta. Treatment of primary human cytotrophoblast cells with NPFF increased the mRNA and protein levels of hCG β, syncytin 1, syncytin 2, and GCM1; and knockdown of NPFFR2 abolished these effects. Interestingly, GCM1 mediated NPFF-induced upregulation of syncytin 1 and syncytin 2, but not hCG β, in primary human cytotrophoblasts. Our results demonstrate that NPFF acts via NPFFR2 to enhance production of hCG β and promote GCM1-dependent expression of syncytin 1 and 2 in human cytotrophoblasts.

Novel dihydroartemisinin dimer containing nitrogen atoms inhibits growth of endometrial cancer cells and may correlate with increasing intracellular peroxynitrite

In the present study, a novel dimer, SM1044, selected from a series of dihydroartemisinin (DHA) derivatives containing nitrogen atoms comprising simple aliphatic amine linkers, showed strong growth inhibition in six types of human endometrial cancer (EC) cells, with half maximal inhibitory concentration (IC₅₀) and 95% confidence interval (CI) < 3.6 (1.16~11.23) μM. SM1044 evoked apoptosis and activated caspase-3, -8 and -9 in a concentration- and time-dependent manner, and these effects were manifested early in RL95-2 compared to KLE cells, possibly correlated with the induction of intracellular ONOO^-. Catalase and uric acid attenuated the growth inhibitory effects of SM1044 on EC cells, but sodium pyruvate did not. In vivo, the average xenograft tumour growth inhibition rates ranged from 35.8% to 49.9%, respectively, after 2.5 and 5.0 mg/kg SM1044 intraperitoneal treatment, and no obvious behavioural and histopathological abnormalities were observed in SM1044-treated mice in this context. SM1044 predominantly accumulated in the uteri of mice after a single injection. SM1044 displayed efficacy as a tumour suppressor with distinct mechanism of action and unique tissue distribution, properties that distinguish it from other artemisinin analogues. Our findings provide a new clue for artemisinin analogue against cancer.

Betacellulin enhances ovarian cancer cell migration by up-regulating Connexin43 via MEK-ERK signaling

Epithelial ovarian cancer is the fifth common cause of cancer death in women and the most lethal gynecological malignancies. Our previous studies have shown that up-regulation of Connexin43, a gap-junction subunit crucial for cell-cell communication, enhances ovarian cancer cell migration. Betacellulin is a member of the epidermal growth factor (EGF) family which can bind to multiple EGF family receptors. Overexpression of betacellulin is found in a variety of cancers and is associated with reduced survival. However, the specific roles and molecular mechanisms of betacellulin in ovarian cancer progression are poorly understood. In the current study, we tested the hypothesis that betacellulin induces ovarian cancer cell migration by up-regulating Connexin43. Our results showed that treatment with betacellulin significantly increased Connexin43 expression and cell migration in both OVCAR4 and SKOV3 ovarian cancer cell lines. Moreover, betacellulin induced the activation of MEK-ERK signaling, and its effects on Connexin43 were inhibited by pre-treatment with U0126. Pre-treatment with AG1478 totally blocked the activation of MEK-ERK signaling but only partially inhibited betacellulin-induced Connexin43 expression and cell migration. Most importantly, betacellulin-induced cell migration was attenuated by knockdown of Connexin43, and co-treatment with gap junction inhibitor carbenoxolone did not alter this effect. Our results suggest a bilateral role of Connexin43 in ovarian cancer migration, and also demonstrate a gap junction-independent mechanism of betacellulin.

Plasminogen activator inhibitor-1 (PAI-1) expression in endometriosis

Purpose

Deep infiltrating endometriosis (DIE) is defined as an endometriotic lesion penetrating to a depth of >5 mm and is associated with pelvic pain, but the underlying mechanisms are unclear. Our objective is to investigate whether plasminogen activator inhibitor-1 expression (PAI-1) in endometriotic tissues is increased in women with DIE.

Methods

In this blinded in vitro study, immunohistochemistry and Histoscore were used to examine the expression of PAI-1 in glandular epithelium (GECs) and stroma (SCs) in a total of 62 women: deep infiltrating uterosacral/rectovaginal endometriosis (DIE; n = 13), ovarian endometrioma (OMA; n = 14), superficial peritoneal uterosacral/cul-de-sac endometriosis (SUP; n = 23), uterine (eutopic) endometrium from women with endometriosis (UE; n = 6), and non-endometriosis eutopic endometrium (UC; n = 6). The following patient characteristics were also collected: age, American Fertility Society stage, hormonal suppression, phase of menstrual cycle, dysmenorrhea score and deep dyspareunia score.

Results

PAI-1 expression in GECs and SCs of the DIE group was significantly higher than that of SUP group (p = 0.01, p = 0.01, respectively) and UE group (p = 0.03, p = 0.04, respectively). Interestingly, increased PAI-1 expression in GECs and SCs was also significantly correlated with increased dysmenorrhea (r = 0.38, p = 0.01; r = 0.34, p = 0.02, respectively).

Conclusions

We found higher expression of PAI-1 in DIE, and an association between PAI-1 and worse dysmenorrhea.

Bone Morphogenetic Protein 2 Promotes Human Trophoblast Cell Invasion by Inducing Activin A Production

Bone morphogenetic protein (BMP) 2 and activin A belong to the TGF-β superfamily and are highly expressed in human endometrium and placenta. Studies have demonstrated that activin A and BMP2 play essential roles in the process of early embryo implantation by promoting human trophoblast cell invasion. However, whether activin A production can be regulated by BMP2 in human trophoblast cells remains unknown. The aim of our study was to determine the effects of BMP2 on activin A production and its role in human trophoblast invasion. Primary human extravillous trophoblast (EVT) cells were used as study models. BMP2 treatment significantly increased inhibin βA (INHBA) mRNA levels and activin A production without altering inhibin α and inhibin βB levels. BMP2-induced EVT cell invasion was attenuated by knockdown of INHBA. The increased INHBA transcription and activin A production by BMP2 were blocked by the type I receptor activin receptor (ACVR)-like kinase 2 (ALK2) and activin receptor-like kinase 3 (ALK3) inhibitor dorsomorphin homolog 1 (DMH-1). BMP2-induced INHBA upregulation was also inhibited by knockdown of type I receptor ALK3 or combined knockdown of type II receptors for BMP2 (BMPR2) and ACVR2A. Whereas BMP2 initiated both canonical SMAD1/5/8 and noncanonical SMAD2/3 signaling, only knockdown of SMAD4, but not SMAD2 and SMAD3, abolished the effects of BMP2 on INHBA. Our results show that BMP2 increases human trophoblast invasion by upregulating INHBA and activin A production via ALK3-BMPR2/ACVR2A-SMAD1/5/8-SMAD4 signaling.

miR-106a Increases Granulosa Cell Viability and Is Downregulated in Women With Diminished Ovarian Reserve

CONTEXT

Women with diminished ovarian reserve (DOR) have reduced fertility, cardiovascular events, and osteoporosis. Although differential microRNA (miRNA) expression has been described in several ovarian disorders, little is known about the role of miRNAs in the pathogenesis of DOR.

OBJECTIVE

Identify differentially expressed miRNAs in DOR and explore the role of miR-106a in human granulosa cell proliferation.

DESIGN

miRNA microarray (n = 3) and quantitative reverse transcription polymerase chain reaction (n = 30) were used to examine miRNA expression in serum and granulosa cells from normal-cycling and women with DOR. Primary human granulosa cells were treated alone or in combination with miR-106a mimic, miR-106a inhibitor, apoptosis signal-regulating kinase 1 (ASK1) small interfering RNA (siRNA), or p38 mitogen-activated protein kinase (MAPK) inhibitor (SB203580) before assessment of cell viability and apoptosis. Western blot was used to measure ASK1 protein and phosphorylation/activation of p38 MAPK. Binding of miR-106a to ASK1 mRNA was examined by 3' untranslated region (3'UTR) luciferase analysis.

RESULTS

Fifteen miRNAs were differentially expressed (n = 30), and miR-106a was downregulated in serum and granulosa cells of women with DOR. miR-106a mimic increased cell viability and attenuated apoptosis, whereas the converse occurred following treatment with miR-106a inhibitor. miR-106a suppressed ASK1 expression by directly targeting its 3'UTR. miR-106a inhibitor increased p38 MAPK phosphorylation/activation, and this effect was abolished by treatment with ASK1 siRNA. Whereas knockdown of ASK1 abolished the effects of miR-106a inhibitor on cell viability/apoptosis, pretreatment with SB203580 did not significantly alter the effects of miR-106a inhibitor.

CONCLUSIONS

Downregulation of miR-106a may contribute to the pathogenesis of DOR by reducing granulosa cell viability and promoting apoptosis via enhanced ASK1 signaling.

TGF-β1 stimulates migration of type II endometrial cancer cells by down-regulating PTEN via activation of SMAD and ERK1/2 signaling pathways

PTEN acts as a tumor suppressor primarily by antagonizing the PI3K/AKT signaling pathway. PTEN is frequently mutated in human cancers; however, in type II endometrial cancers its mutation rate is very low. Overexpression of TGF-β1 and its receptors has been reported to correlate with metastasis of human cancers and reduced survival rates. Although TGF-β1 has been shown to regulate PTEN expression through various mechanisms, it is not yet known if the same is true in type II endometrial cancer. In the present study, we show that treatment with TGF-β1 stimulates the migration of two type II endometrial cancer cell lines, KLE and HEC-50. In addition, TGF-β1 treatment down-regulates both mRNA and protein levels of PTEN. Overexpression of PTEN or inhibition of PI3K abolishes TGF-β1-stimulated cell migration. TGF-β1 induces SMAD2/3 phosphorylation and knockdown of common SMAD4 inhibits the suppressive effects of TGF-β1 on PTEN mRNA and protein. Interestingly, TGF-β1 induces ERK1/2 phosphorylation and pre-treatment with a MEK inhibitor attenuates the suppression of PTEN protein, but not mRNA, by TGF-β1. This study provides important insights into the molecular mechanisms mediating TGF-β1-induced down-regulation of PTEN and demonstrates an important role of PTEN in the regulation of type II endometrial cancer cell migration.

Bone morphogenetic protein 2 promotes human trophoblast cell invasion by upregulating N-cadherin via non-canonical SMAD2/3 signaling

BMP2 expression is spatiotemporally correlated with embryo implantation and is crucial for endometrial decidualization and fertility in mice. BMP2 has been reported to increase the mesenchymal adhesion molecule N-cadherin and enhance cell invasion in cancer cells; moreover, studies suggest that N-cadherin promotes placental trophoblast invasion. However, whether BMP2 can promote trophoblast cell invasion during placentation remains unknown. The objective of our study was to investigate the effects of BMP2 on human trophoblast cell invasion and the involvement of N-cadherin and SMAD signaling. Primary and immortalized (HTR8/SVneo) cultures of human extravillous trophoblast (EVT) cells were used as study models. Treatment with recombinant human BMP2 increased HTR8/SVneo cell transwell Matrigel invasion as well as N-cadherin mRNA and protein levels, but had no significant effect on cell proliferation. Likewise, BMP2 treatment enhanced primary human EVT cell invasion and N-cadherin production. Basal and BMP2-induced invasion were attenuated by small interfering RNA-mediated downregulation of N-cadherin in both HTR8/SVneo and primary EVT cells. Intriguingly, BMP2 induced the phosphorylation/activation of both canonical SMAD1/5/8 and non-canonical SMAD2/3 signaling in HTR8/SVneo and primary EVT cells. Knockdown of SMAD2/3 or common SMAD4 totally abolished the effects of BMP2 on N-cadherin upregulation in HTR8/SVneo cells. Upregulation of SMAD2/3 phosphorylation and N-cadherin were totally abolished by type I receptor activin receptor-like kinases 2/3 (ALK2/3) inhibitor DMH1; moreover, knockdown of ALK2 or ALK3 inhibited N-cadherin upregulation. Interestingly, activation of SMAD2/3 and upregulation of N-cadherin were partially attenuated by ALK4/5/7 inhibitor SB431542 or knockdown of ALK4, but not ALK5. Our results show that BMP2 promotes trophoblast cell invasion by upregulating N-cadherin via non-canonical ALK2/3/4-SMAD2/3-SMAD4 signaling.

Activin B promotes endometrial cancer cell migration by down-regulating E-cadherin via SMAD-independent MEK-ERK1/2-SNAIL signaling

High-risk type II endometrial cancers account for ~30% of cases but ~75% of deaths due, in part, to their tendency to metastasize. Histopathological studies of type II endometrial cancers (non-endometrioid, mostly serous) suggest overproduction of activin B and down-regulation of E-cadherin, both of which are associated with reduced survival. Our previous studies have shown that activin B increases the migration of type II endometrial cancer cell lines. However, little is known about the relationship between activin B signaling and E-cadherin in endometrial cancer. We now demonstrate that activin B treatment significantly decreases E-cadherin expression in both a time- and concentration-dependent manner in KLE and HEC-50 cell lines. Interestingly, these effects were not inhibited by knockdown of SMAD2, SMAD3 or SMAD4. Rather, the suppressive effects of activin B on E-cadherin were mediated by MEK-ERK1/2-induced production of the transcription factor SNAIL. Importantly, activin B-induced cell migration was inhibited by forced-expression of E-cadherin or pre-treatment with the activin/TGF-β type I receptor inhibitor SB431542 or the MEK inhibitor U0126. We have identified a novel SMAD-independent pathway linking enhanced activin B signaling to reduced E-cadherin expression and increased migration in type II endometrial cancer.

HOXB4 Immunoreactivity in Endometrial Tissues From Women With or Without Endometriosis

Endometriosis is a common disease characterized by the presence of ectopic endometrial tissue. Although the pathogenesis of endometriosis remains unclear, several factors have been implicated, including the dysregulation of homeobox ( HOX) genes. Our objective was to investigate the localization and immunoreactivity of HOXB4 in endometrial tissues from women with or without endometriosis. We studied samples of eutopic endometrium (EE), endometriomas (Eoma), superficial endometriosis (SE), and deep infiltrating endometriosis (DIE) from 34 women with endometriosis, as well as eutopic endometrium from 38 women without endometriosis (EC). HOXB4 localization and immunoreactivity was assessed using immunohistochemistry and histoscore analysis. Data were analyzed with and without stratification by menstrual cycle phase. HOXB4 protein was present in the nuclei of endometrial glandular epithelial cells but not in stromal cells. HOXB4 immunoreactivity was reduced in DIE samples compared to all other groups. A smaller reduction in HOXB4 immunoreactivity was observed in SE samples compared to EC samples. HOXB4 immunoreactivity was significantly greater in proliferative compared to secretory phase samples in the EC group but not in EE, Eoma, or DIE groups. Among only proliferative phase samples, HOXB4 immunoreactivity was reduced in EE, Eoma, and DIE groups compared to EC. Based on these data, we suggest that an impaired capacity of eutopic and ectopic endometrial tissue to upregulate levels of HOXB4 during the proliferative phase may play a role in the pathogenesis of endometriosis and that further downregulation of HOXB4 may enhance ectopic implant invasiveness.

SMAD1/5 mediates bone morphogenetic protein 2-induced up-regulation of BAMBI expression in human granulosa-lutein cells

Bone morphogenetic protein and activin membrane-bound inhibitor (BAMBI) is a transforming growth factor β (TGF-β) type I receptor antagonist that negatively regulates TGF-β and bone morphogenetic protein (BMP) signaling. BAMBI has been shown to be regulated by TGF-β signaling; however, whether BAMBI can be regulated by BMP signaling remains to be determined. The aim of this study was to investigate the effect of BMP2 on the regulation of BAMBI expression in human granulosa-lutein cells and the underlying mechanisms. Both primary and immortalized human granulosa-lutein cells were used as research models. Using dual inhibition approaches, our results showed that BMP2 activated SMAD1/5/8 phosphorylation and up-regulated BAMBI mRNA levels, which was reversed by the BMP type I receptor inhibitors, DMH-1 and dorsomorphin, but not by SB431542 (activin/TGF-β type I receptor inhibitor). Moreover, the combined knockdown of SMAD1 and SMAD5 completely abolished the BMP2-induced up-regulation of BAMBI. Similarly, knockdown of SMAD4 reversed the BMP2-induced up-regulation of BAMBI. Pre-treatment with BMP2 inhibited the TGF-β1-induced phosphorylation of SMAD2/3 and up-regulation of MMP2, and these inhibitory effects were reversed by knockdown of endogenous BAMBI. Our findings indicate that BAMBI is a BMP-responsive gene and that BAMBI participates in the negative feedback regulation of TGF-β signaling in the human ovary.

TGFβ1 induces endometrial cancer cell adhesion and migration by up-regulating integrin αvβ3 via SMAD-independent MEK-ERK1/2 signaling

Endometrial cancer is the most common, and second most lethal, gynecological malignancy, and its rates of incidence and death are growing. This is likely attributable to increased numbers of high-risk type II endometrial cancers which account for ~30% of cases but ~75% of deaths due to their aggressive and metastatic behaviour. Histopathological and in vitro functional studies suggest that aberrant TGFβ1 signaling may contribute to endometrial cancer development and the acquisition of invasive/metastatic characteristics. However, little is known about the cellular and molecular mechanisms of TGFβ1 in high-risk endometrial cancers. In the present study, we examined the roles and mechanisms of TGFβ1 on cell adhesion and motility in type II endometrial cancer cell lines, KLE and HEC-1B. We show that treatment with TGFβ1 increases cell adhesion to vitronectin and transwell cell migration. We also demonstrate that TGFβ1 treatment increases integrin β3 and αv mRNA and protein levels via SMAD-independent MEK-ERK1/2 signaling. Importantly, siRNA depletion or antibody-mediated blocking of integrin αvβ3 reversed the effects of TGFβ1 on cell adhesion and migration. Our results suggest that TGFβ1-MEK-ERK1/2-integrin αvβ3 signaling could contribute to the invasive behaviour of high-risk endometrial cancer by promoting cell adhesion and migration.

Prevalence of Prediabetes Risk in Offspring Born to Mothers with Hyperandrogenism

Background

Excessive androgen exposure during pregnancy has been suggested to induce diabetic phenotypes in offspring in animal models. The aim of this study was to investigate whether pregestational maternal hyperandrogenism in human influenced the glucose metabolism in offspring via epigenetic memory from mother's oocyte to child's somatic cells.

Methods

Of 1782 reproductive-aged women detected pregestational serum androgen, 1406 were pregnant between 2005 and 2010. Of 1198 women who delivered, 1116 eligible mothers (147 with hyperandrogenism and 969 normal) were recruited. 1216 children (156 children born to mothers with hyperandrogenism and 1060 born to normal mother) were followed up their glycometabolism in mean age of 5 years. Imprinting genes of oocyte from mothers and lymphocytes from children were examined. A pregestational hyperandrogenism rat model was also established.

Findings

Children born to women with hyperandrogenism showed increased serum fasting glucose and insulin levels, and were more prone to prediabetes (adjusted RR: 3.98 (95%CI 1.16–13.58)). Oocytes from women with hyperandrogenism showed increased insulin-like growth factor 2 (IGF2) expression. Lymphocytes from their children also showed increased IGF2 expression and decreased IGF2 methylation. Treatment of human oocytes with dihydrotestosterone upregulated IGF2 and downregulated DNMT3a levels. In rat, pregestational hyperandrogenism induced diabetic phenotypes and impaired insulin secretion in offspring. In consistent with the findings in human, hyperandrogenism also increased Igf2 expression and decreased DNMT3a in rat oocytes. Importantly, the same altered methylation signatures of Igf2 were identified in the offspring pancreatic islets.

Interpretation

Pregestational hyperandrogenism may predispose offspring to glucose metabolism disorder via epigenetic oocyte inheritance.

Clinical trial registry no.: ChiCTR-OCC-14004537; www.chictr.org.

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Maternal hyperandrogenism may increase the risks of glucose metabolism disorder and prediabetes in their children.

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High androgen levels in women may directly increased IGF2 expression and decreased IGF2 methylation in oocytes

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Intergenerational inheritance of epigenetic alteration could be regarded important in determining development of diabetes.

Hyperandrogenemia can be observed in most patients with polycystic ovarian syndrome that is a common endocrine disorder in women of reproductive age, especially in subfertile women. We found that maternal hyperandrogenism may increase the risks of glucose metabolism disorder and prediabetes in their children. Also, Data from human and rat suggest that this glucose metabolism disorder may be mediated by DNA methylation modifications, and this kind of epigenetic modification may be transmitted from oocytes of mothers to somatic cells of offspring. Hence, intergenerational inheritance of epigenetic alteration should be regarded important in determining development of diabetes in the future.

Activin A-induced increase in LOX activity in human granulosa–lutein cells is mediated by CTGF

Lysyl oxidase (LOX) is the key enzyme involved in the crosslinking of collagen and elastin that is essential for the formation of extracellular matrix (ECM). LOX-mediated ECM remodeling plays a critical role in follicle development, oocyte maturation and corpus luteum formation. To date, the regulation of LOX in human ovary has never been elucidated. Activin A and its functional receptors are highly expressed in ovarian follicles from an early developmental stage. They locally regulate follicle progression. The aim of this study was to investigate the effects of activin A on the expression of LOX and its extracellular enzyme activity in primary and immortalized human granulosa–lutein cells obtained from patients undergoing anin vitrofertilization procedure. We demonstrated that activin A significantly upregulated the expression of connective tissue growth factor (CTGF) and LOX via an activin/TGF-β type I receptor mediated-signaling pathway. Using a target depletion small interfering RNA knockdown approach, we further confirmed that the upregulation of CTGF expression resulted in an activin-A-induced increases in LOX expression and activity. These findings may provide insight into the mechanisms by which intrafollicular growth factors regulate the expression of LOX for ECM formation and tissue remodeling in the human ovary.

Activin B induces human endometrial cancer cell adhesion, migration and invasion by up-regulating integrin β3 via SMAD2/3 signaling

Endometrial cancer is the fourth most common female cancer and the most common gynecological malignancy. Although it comprises only ~10% of all endometrial cancers, the serous histological subtype accounts for ~40% of deaths due to its aggressive behavior and propensity to metastasize. Histopathological studies suggest that elevated expression of activin/inhibin βB subunit is associated with reduced survival in non-endometrioid endometrial cancers (type II, mostly serous). However, little is known about the specific roles and mechanisms of activin (βB dimer) in serous endometrial cancer growth and progression. In the present study, we examined the biological functions of activin B in type II endometrial cancer cell lines, HEC-1B and KLE. Our results demonstrate that treatment with activin B increases cell migration, invasion and adhesion to vitronectin, but does not affect cell viability. Moreover, we show that activin B treatment increases integrin β3 mRNA and protein levels via SMAD2/3-SMAD4 signaling. Importantly, siRNA knockdown studies revealed that integrin β3 is required for basal and activin B-induced cell migration, invasion and adhesion. Our results suggest that activin B-SMAD2/3-integrin β3 signaling could contribute to poor patient survival by promoting the invasion and/or metastasis of type II endometrial cancers.

Transforming growth factor-β1 increases lysyl oxidase expression by downregulating MIR29A in human granulosa lutein cells

Lysyl oxidase (LOX), a key enzyme in the formation and stabilization of the extracellular matrix, is expressed in granulosa cells and plays a critical role in the regulation of granulosa cell differentiation, oocyte maturation and ovulation. To date, the regulation of LOX expression in human granulosa cells remains largely unknown. In this study, using primary and immortalized human granulosa lutein cells, we demonstrated that transforming growth factor (TGF)-β1 (TGFB1) upregulated LOX expression and downregulated microRNA-29a (MIR29A) expression via a TGF-β type I receptor-mediated signaling pathway. Additionally, we showed that MIR29A downregulated the expression of LOX in both types of cells. Furthermore, the downregulation of MIR29A contributed to the TGFB1-induced increase in LOX expression because the inhibition of MIR29A with a MIR29A inhibitor not only reversed the MIR29A-induced downregulation of LOX but also enhanced the TGFB1-induced upregulation of LOX. Our findings suggest that TGFB1 and MIR29A may play essential roles in the regulation of extracellular matrix remodeling during the periovulatory phase.

Differential activation of noncanonical SMAD2/SMAD3 signaling by bone morphogenetic proteins causes disproportionate induction of hyaluronan production in immortalized human granulosa cells

Successful fertilization depends upon proper cumulus-oocyte complex (COC) expansion. Synthesized by hyaluronan synthases (HASs), hyaluronan forms the backbone of the COC matrix and plays a critical role in COC expansion. This study investigated the effects and mechanisms of ovarian BMPs on HAS expression and hyaluronan production in human granulosa cells. Treatment with BMP4, BMP6, BMP7 or BMP15 induced differing levels of noncanonical SMAD2/3, but equal levels of canonical SMAD1/5/8, phosphorylation which were mirrored by differing levels of HAS2 up-regulation and hyaluronan production. The effects of BMP4 and BMP15 on HAS2 mRNA were partially reversed by knockdown of SMAD3, and blocked by knockdown of SMAD2+SMAD3 or SMAD4. BMP4-induced SMAD2/3 phosphorylation and HAS2 mRNA up-regulation were mediated by both BMP and activin/transforming growth factor-β type I receptors. Our results suggest differential activation of noncanonical SMAD2/SMAD3 signaling by BMPs causes disproportionate induction of HAS2 expression and hyaluronan production in immortalized human granulosa cells.

Gonadotropin-releasing hormone and gonadotropin-releasing hormone receptor are expressed at tubal ectopic pregnancy implantation sites

OBJECTIVE

To investigate whether gonadotropin-releasing hormone (GnRH) and GnRH receptor (GnRHR) are expressed at tubal ectopic pregnancy sites, and to study the potential role of GnRH signaling in regulating immortalized human trophoblast cell viability.

DESIGN

Immunohistochemical and experimental studies.

SETTING

Academic research laboratory.

PATIENT(S)

Fallopian tube implantation sites (n = 25) were collected from women with ectopic pregnancy. First-trimester human placenta biopsies (n = 5) were obtained from elective terminations of pregnancy.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

GnRH and GnRHR expression was examined by means of immunohistochemistry and histoscoring. Trophoblastic BeWo choriocarcinoma and immortalized extravillous trophoblast (HTR-8/SVneo) cell viability was examined by means of cell counting after incubation with GnRH and/or GnRH antagonist (Antide).

RESULT(S)

GnRH and GnRHR immunoreactivity was detected in cytotrophoblast, syncytiotrophoblast, and extravillous trophoblast in all women with tubal pregnancy. GnRH immunoreactivity was higher and GnRHR immunoreactivity lower in syncytiotrophoblast compared with cytotrophoblast. GnRH and GnRHR immunoreactivity was detected in adjacent fallopian tube epithelium. Whereas neither GnRH nor Antide altered HTR-8/SVneo cell viability, treatment with GnRH significantly increased the overall cell viability of BeWo cells at 48 and 72 hours, and these effects were abolished by pretreatment with Antide.

CONCLUSION(S)

GnRH and GnRHR are expressed in trophoblast cell populations and fallopian tube epithelium at tubal ectopic pregnancy sites. GnRH increases BeWo cell viability, an effect mediated by the GnRHR. Further work is required to investigate the potential role of GnRH signaling in ectopic pregnancy.

GnRH regulates trophoblast invasion via RUNX2-mediated MMP2/9 expression

STUDY HYPOTHESIS

We hypothesized that Runt-related transcription factor 2 (RUNX2), matrix metalloproteinase (MMP)2 and MMP9 are involved in basal and gonadotrophin-releasing hormone (GnRH)-induced human extravillous trophoblast (EVT) cell invasion.

STUDY FINDING

Our finding indicates that GnRH-induced RUNX2 expression enhances the invasive capacity of EVT cells by modulating the expression of MMP2 and MMP9.

WHAT IS KNOWN ALREADY

GnRH is expressed in first-trimester placenta and exerts pro-invasive effects on EVT cells in vitro. RUNX2 regulates MMP2 and MMP9 expression and is often associated with invasive phenotypes.

STUDY DESIGN, SAMPLES/MATERIALS, METHODS

First-trimester human placenta (n = 9) was obtained from women undergoing elective termination of pregnancy. The localization of RUNX2, MMP2 and MMP9 in first-trimester human placenta was examined by immunohistochemistry. Primary or immortalized (HTR-8/SVneo) EVT cells were treated alone or in combination with GnRH, GnRH antagonist Antide, MAPK kinase inhibitor PD98095, phosphatidylinositol 3-kinase inhibitor LY294002, MMP2/9 inhibitor or small interfering RNAs (siRNAs) targeting RUNX2, MMP2 and/or MMP9. Protein and mRNA levels were measured by western blot and RT-PCR, respectively. Cell invasiveness was evaluated by transwell Matrigel or collagen I invasion assays.

MAIN RESULTS AND THE ROLE OF CHANCE

RUNX2, MMP2 and MMP9 were detected in the cell column regions of human first-trimester placental villi. GnRH treatment increased RUNX2 mRNA and protein levels in HTR-8/SVneo cells and primary EVTs, and these effects were attenuated by co-treatment with Antide, PD98095 or LY294002. Down-regulation of RUNX2 by siRNA reduced basal and GnRH-induced MMP2/9 expression and cell invasion. Moreover, pharmacological inhibition or siRNA-mediated knockdown of MMP2/9 reduced basal and GnRH-induced cell invasion.

LIMITATIONS, REASONS FOR CAUTION

The lack of an in vivo model is the major limitation of our in vitro study.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings provide important insight into the functions of the GnRH - GnRH receptor system in early implantation and placentation.

LARGE SCALE DATA

Not applicable.

STUDY FUNDING AND COMPETING INTERESTS

This research was supported by Canadian Institutes of Health Research (Grant #143317) to P.C.K.L. The authors have nothing to disclose.

Activin A Increases Human Trophoblast Invasion by Inducing SNAIL-Mediated MMP2 Up-Regulation Through ALK4

CONTEXT

Activin A increases matrix metalloproteinase (MMP) 2 expression and cell invasion in human trophoblasts, but whether the expression of MMP2 is essential for the proinvasive effect of activin A has yet to be determined. Moreover, the identity of the activin receptor-like kinase (ALK; TGF-β type I receptors) and downstream transcription factors (eg, SNAIL and SLUG) mediating the effects of activin on MMP2 expression and trophoblast cell invasion remains unknown.

OBJECTIVE

To elucidate the role of MMP2 in activin A-induced human trophoblast cell invasion as well as the involvement of ALK4 and SNAIL.

DESIGN

HTR8/SVneo immortalized human extravillous cytotrophoblast (EVT) cells and primary cultures of human first-trimester EVT cells were used as study models. Small interfering RNA (siRNA)-mediated knockdown approaches were used to investigate the molecular determinants of activin A-mediated functions.

MAIN OUTCOME MEASURES

Levels of mRNA and protein were examined by reverse transcription-quantitative real-time PCR and Western blot, respectively. Cell invasiveness was measured by Matrigel-coated transwell assays.

RESULTS

Treatment of HTR8/SVneo cells with activin A increased the production of SNAIL, SLUG, and MMP2 without altering that of MMP9, TIMP1, TIMP2, TWIST, RUNX2, ZEB1, or ZEB2. Similarly, activin A up-regulated the mRNA and protein levels of SNAIL and MMP2 in primary EVT cells. Knockdown of SNAIL attenuated activin A-induced MMP2 up-regulation in HTR8/SVneo and primary EVT cells. In HTR8/SVneo cells, activin A-induced production of SNAIL and MMP2 was abolished by pretreatment with the TGF-β type I receptor (ALK4/5/7) inhibitor SB431542 or siRNA targeting ALK4, SMAD2/3, or common SMAD4. Likewise, knockdown of ALK4 or SMAD4 abolished the stimulatory effects of activin A on SNAIL and MMP2 expression in primary EVT cells. Importantly, activin A-induced HTR8/SVneo and primary EVT cell invasion were attenuated by siRNA-mediated depletion of ALK4 or MMP2.

CONCLUSION

Activin A induces human trophoblast cell invasion by inducing SNAIL-mediated MMP2 expression through ALK4 in a SMAD2/3-SMAD4-dependent manner.

Vascular Endothelial Growth Factor-A (VEGF-A) Mediates Activin A-Induced Human Trophoblast Endothelial-Like Tube Formation

Remodeling of maternal spiral arteries during pregnancy requires a subpopulation of extravillous cytotrophoblasts (EVTs) to differentiate into endovascular EVTs. Activin A, which is abundantly expressed at the maternal-fetal interface, has been shown to promote trophoblast invasion, but its role in endovascular differentiation remains unknown. Vascular endothelial growth factor-A (VEGF-A) is well recognized as a key regulator in trophoblast endovascular differentiation. Whether and how activin A might regulate VEGF-A production in human trophoblasts and its relationship to endovascular differentiation have yet to be determined. In the present study, we found that activin A increased VEGF-A production in primary and immortalized (HTR8/SVneo) human EVT cells. In addition, activin A enhanced HTR8/SVneo endothelial-like tube formation, and these effects were attenuated by pretreatment with small interfering RNA targeting VEGF-A or the VEGF receptor 1/2 inhibitor SU4312. Pretreatment with the activin/TGF-β type 1 receptor (ALK4/5/7) inhibitor SB431542 abolished the stimulatory effects of activin A on phosphorylated mothers against decapentaplegic (SMAD)-2/3 phosphorylation, VEGF-A production, and endothelial-like tube formation. Moreover, small interfering RNA-mediated down-regulation of SMAD2, SMAD3, or common SMAD4 abolished the effects of activin A on VEGF-A production and endothelial-like tube formation. In conclusion, activin A may promote human trophoblast cell endothelial-like tube formation by up-regulating VEGF-A production in an SMAD2/3-SMAD4-dependent manner. These findings provide insight into the cellular and molecular events regulated by activin A during human implantation.

BMP4 and BMP7 Suppress StAR and Progesterone Production via ALK3 and SMAD1/5/8-SMAD4 in Human Granulosa-Lutein Cells

Adequate production of progesterone by the corpus luteum is critical to the successful establishment of pregnancy. In animal models, bone morphogenetic protein (BMP) 4 and BMP7 have been shown to suppress either basal or gonadotropin-induced progesterone production, depending on the species examined. However, the effects of BMP4 and BMP7 on progesterone production in human granulosa cells are unknown. In the present study, we used immortalized (SVOG) and primary human granulosa-lutein cells to investigate the effects of BMP4 and BMP7 on steroidogenic acute regulatory protein (StAR) expression and progesterone production and to examine the underlying molecular mechanism. Treatment of primary and immortalized human granulosa cells with recombinant BMP4 or BMP7 decreased StAR expression and progesterone accumulation. In SVOG cells, the suppressive effects of BMP4 and BMP7 on StAR expression were blocked by pretreatment with inhibitors of activin receptor-like kinase (ALK)2/3/6 (dorsomorphin) or ALK2/3 (DMH1) but not ALK4/5/7 (SB-431542). Moreover, small interfering RNA-mediated depletion of ALK3, but not ALK2 or ALK6, reversed the effects of BMP4 and BMP7 on StAR expression. Likewise, BMP4- and BMP7-induced phosphorylation of SMAD 1/5/8 was reversed by treatment with DMH1 or small interfering RNA targeting ALK3. Knockdown of SMAD4, the essential common SMAD for BMP/TGF-β signaling, abolished the effects of BMP4 and BMP7 on StAR expression. Our results suggest that BMP4 and BMP7 down-regulate StAR and progesterone production via ALK3 and SMAD1/5/8-SMAD4 signaling in human granulosa-lutein cells.

AP-1 Transcription Factors c-FOS and c-JUN Mediate GnRH-Induced Cadherin-11 Expression and Trophoblast Cell Invasion

GnRH is expressed in first-trimester human placenta and increases cell invasion in extravillous cytotrophoblasts (EVTs). Invasive phenotypes have been reported to be regulated by transcription factor activator protein 1 (AP-1) and mesenchymal cadherin-11. The aim of our study was to investigate the roles of AP-1 components (c-FOS/c-JUN) and cadherin-11 in GnRH-induced cell invasion in human EVT cells. Phosphorylated c-FOS and phosphorylated c-JUN were detected in the cell column regions of human first-trimester placental villi by immunohistochemistry. GnRH treatment increased c-FOS, c-JUN, and cadherin-11 mRNA and protein levels in immortalized EVT (HTR-8/SVneo) cells. Moreover, GnRH treatment induced c-FOS and c-JUN protein phosphorylation and nuclear accumulation. Pretreatment with antide, a GnRH antagonist, attenuated GnRH-induced cadherin-11 expression. Importantly, basal and GnRH-induced cadherin-11 expression and cell invasion were reduced by small interfering RNA-mediated knockdown of c-FOS, c-JUN, and cadherin-11 in HTR-8/SVneo cells. Our results suggest that GnRH induces the expression and phosphorylation of the AP-1 transcription factors c-FOS and c-JUN in trophoblast cells, which contributes to GnRH-induced elevation of cadherin-11 expression and cell invasion.

Transforming growth factor-α induces human ovarian cancer cell invasion by down-regulating E-cadherin in a Snail-independent manner

Transforming growth factor-α (TGF-α), like epidermal growth factor (EGF) and amphiregulin (AREG) binds exclusively to EGF receptor (EGFR). We have previously demonstrated that EGF, AREG and TGF-α down-regulate E-cadherin and induce ovarian cancer cell invasion, though whether these ligands use the same molecular mediators remains unknown. We now show that, like EGF, TGF-α- and AREG-induced E-cadherin down-regulation involves both EGFR and HER2. However, in contrast to EGF and AREG, the transcription factor Snail is not required for TGF-α-induced E-cadherin down-regulation. This study shows that TGF-α uses common and divergent molecular mediators to regulate E-cadherin expression and cell invasion.

Growth differentiation factor 8 down-regulates pentraxin 3 in human granulosa cells

Growth differentiation factor 8 (GDF8), also known as myostatin, is highly expressed in the mammalian musculoskeletal system and plays critical roles in the regulation of skeletal muscle growth. Though not exclusively expressed in the musculoskeletal system, the expression and biological function of GDF8 has never been examined in the human ovary. Pentraxin 3 (PTX3) plays a key role in the assembly of extracellular matrix, which is essential for cumulus expansion, ovulation and in vivo fertilization. The aim of this study was to investigate GDF8 expression and function in human granulosa cells and to examine its underlying molecular determinants. An established immortalized human granulosa cell line (SVOG), granulosa cell tumor cell line (KGN) and primary granulosa-lutein cells were used as study models. We now demonstrate for the first time that GDF8 is expressed in human granulosa cells and follicular fluid. All 16 follicular fluid samples tested contained GDF8 protein at an average concentration of 3 ng/ml. In addition, GDF8 treatment significantly decreased PTX3 mRNA and protein levels. These suppressive effects, along with the induction of SMAD2/3 phosphorylation, were abolished by co-treatment with the ALK4/5/7 inhibitor SB431542. Knockdown of ALK5, ACVR2A/ACVR2B or SMAD4 reversed the effects of GDF8-induced PTX3 suppression. These results indicate that GDF8 down-regulates PTX3 expression via ACVR2A/ACVR2B-ALK5-mediated SMAD-dependent signaling in human granulosa cells. These novel findings support a potential role for GDF8 in the regulation of follicular function, likely via autocrine effects on human granulosa cells.

Recombinant BMP4 and BMP7 increase activin A production by up-regulating inhibin βA subunit and furin expression in human granulosa-lutein cells

CONTEXT

Granulosa cell-derived activins play important roles in the regulation of ovarian functions. To date, there is limited information pertaining to the intracellular regulation, assembly, and secretion of endogenous activin A in human granulosa cells.

OBJECTIVE

The aim of this study was to examine the effects of BMP4 and BMP7 on furin expression and activin A production as well as the underlying mechanisms of action in human granulosa cells.

DESIGN

An established immortalized human granulosa cell line (SVOG) and primary granulosa-lutein cells were used as study models. Expression of inhibin subunits and furin as well as activin A accumulation were examined after exposure to recombinant human BMP4 or BMP7. A BMP type I receptor inhibitor (dorsomorphin), a furin inhibitor (Decanoyl-Arg-Val-Lys-Arg-chloromethylketone), and small interfering RNAs targeting SMAD4 and furin were used to verify the specificity of the effects and investigate potential mechanisms.

SETTING

The study was conducted in an academic center.

MAIN OUTCOME MEASURES

Specific mRNA and protein levels were examined using real time qPCR and Western blot. Activin A levels were measured using enzyme immunoassay.

RESULTS

Treatment with bone morphogenetic protein (BMP) 4 and BMP7 significantly increased furin mRNA and protein, inhibin βA mRNA, and activin A accumulation. Pre-treatment with dorsomorphin or SMAD4 knockdown reversed the stimulatory effects of BMP4 and BMP7 on furin and inhibin βA expression. In addition, furin knockdown or pre-treatment with a furin inhibitor attenuated the BMP4- and BMP7-induced accumulation of activin A.

CONCLUSION

Recombinant BMP4 and BMP7 increase the production of bioactive mature activin A by up-regulating both the production and proteolytic processing of inhibin βA subunit in human granulosa cells. The enhancement of inhibin βA subunit processing is attributable to a SMAD-dependent up-regulation of its proprotein convertase, furin. These findings provide a potential mechanism by which theca cells can regulate neighboring granulosa cells in the ovary.

Recombinant BMP4 and BMP7 downregulate pentraxin 3 in human granulosa cells

CONTEXT

Theca cell-derived bone morphogenetic protein 4 (BMP4) and BMP7 are important regulators of folliculogenesis and have been shown to inhibit luteinization. Pentraxin 3 (PTX3) plays a critical role in the assembly of the cumulus oophorus extracellular matrix, which is essential for cumulus expansion during ovulation and may be modulated by BMP4 and BMP7.

OBJECTIVE

The aim of this study was to investigate the effects of BMP4 and BMP7 on the expression of PTX3 in human granulosa cells and to examine their underlying molecular determinants.

DESIGN

An established immortalized human granulosa cell line (SVOG), a granulosa cell tumor cell line (KGN), and primary granulosa-lutein cells were used as study models. PTX3 expression and accumulation as well as Smad1/5/8 phosphorylation were examined after exposure to recombinant human BMP4 and BMP7. BMP type I receptor involvement was investigated with inhibitors (dorsomorphin and DMH-1 (4-[6-[4-(1-Methylethoxy)phenyl]pyrazolo[1,5-a]pyrimidin-3-yl]-quinoline)) and small interfering RNAs targeting activin receptor-like kinase (ALK)2, ALK3, and/or ALK6. Small interfering RNAs targeting Smad4 were used to verify the involvement of Smad signaling.

SETTING

The study was conducted at an academic research center.

MAIN OUTCOME MEASURES

Quantitative RT-PCR and Western blot were used to measure mRNA and protein levels, respectively. Levels of PTX3 and BMP4 were measured by ELISA.

RESULTS

Treatment with BMP4 and BMP7 significantly decreased PTX3 mRNA and protein production. These suppressive effects, along with the induction of Smad1/5/8 phosphorylation, were attenuated by cotreatment with 2 BMP type I receptor inhibitors (dorsomorphin and/or DMH-1). Combined knockdown (ALK3/ALK6 for BMP4 and ALK2/ALK3 for BMP7) reversed the effects of BMP4- and BMP7-induced Smad1/5/8 phosphorylation and PTX3 suppression. Furthermore, Smad4 knockdown reversed the suppressive effects of BMP4 and BMP7 on PTX3 expression. In follicular fluid, concentrations of PTX3 were negatively correlated with concentrations of BMP4.

CONCLUSION

BMP4 and BMP7 use differential subsets of BMP type I receptors to downregulate PTX3 expression via Smad-dependent signaling in human granulosa cells.

Activin A, B, and AB increase human trophoblast cell invasion by up-regulating N-cadherin

CONTEXT

Inhibin β-subunits and activin receptors are expressed by human trophoblast cells. Although activin A has been shown to enhance human trophoblast cell invasion, whether two additional activin isoforms, activin B and AB, exert similar effects remains unknown. Moreover, whether the expression of mesenchymal adhesion molecule neural cadherin (N-cadherin) is essential for this proinvasive effect of activin has yet to be determined.

OBJECTIVE

To examine the effects of all three activin isoforms on human trophoblast cell invasion and the involvement of N-cadherin.

DESIGN

HTR8/SVneo immortalized extravillous cytotrophoblast cells and primary cultures of human extravillous cytotrophoblast cells were used as study models. Small interfering RNA-mediated knockdown approaches were used to investigate the molecular determinants of activin-mediated functions.

SETTING

An academic research center.

MAIN OUTCOME MEASURES

Reverse transcription-quantitative real-time PCR and Western blot analysis were used to examine mRNA and protein levels, respectively. Cell invasiveness was assessed by Matrigel-coated transwell assays.

RESULTS

All three activin isoforms produced comparable increases in HTR8/SVneo cell invasion as well as N-cadherin expression. In addition, the up-regulatory effect of activin isoforms on N-cadherin was confirmed in primary cultures of human trophoblast cells. Interestingly, small interfering RNA-mediated down-regulation of N-cadherin attenuated basal and activin-induced invasion of both HTR8/SVneo and primary trophoblast cells. All three activin isoforms induced equivalent phosphorylation of SMAD2 and SMAD3. Importantly, activin-stimulated cell invasion, up-regulation of N-cadherin, as well as activation of SMAD2/SMAD3 were abolished by the TGF-β type I receptor inhibitor SB431542 in HTR8/SVneo cells. Furthermore, knockdown of SMAD2/3 or common SMAD4 abolished the stimulatory effects of all three activin isoforms on N-cadherin expression.

CONCLUSION

Activin A, B, and AB produce comparable increases in human trophoblast cell invasion by up-regulating N-cadherin expression in a SMAD2/3-SMAD4-dependent manner.

Effects of recombinant activins on steroidogenesis in human granulosa-lutein cells

CONTEXT

Exerting a broad range of biological effects in various tissues, activins are homo- or heterodimers of activin/inhibin β-subunits (βA, βB, βC, and βE in humans). Although activins A (βAβA), B (βBβB), AB (βAβB), and AC (βAβC) have been demonstrated in the female reproductive system, little is known about their individual functions in the ovary.

OBJECTIVE

To investigate the biological roles and activities of activins in regulating steroidogenesis in human granulosa cells.

DESIGN

Human granulosa-lutein cells obtained from 32 patients undergoing in vitro fertilization were used to investigate the effects of activin A, B, AB, and AC on the expression of steroidogenic enzymes and steroid production.

SETTING

An academic research center.

MAIN OUTCOME MEASURES

mRNA and protein levels were examined by reverse transcription quantitative real-time PCR and Western blot analysis, respectively. The production of estradiol and progesterone was measured by enzyme immunoassay.

RESULTS

P450 aromatase, FSH receptor, and estradiol levels were increased, whereas steroidogenic acute regulatory protein (StAR), LH receptor, and progesterone levels were decreased after treatment with activin A, B, and AB, but not activin AC. FSH or LH induced the production of aromatase/estradiol and StAR/progesterone; however, pretreatment with activin A, B, or AB enhanced the effects of gonadotropins on aromatase/estradiol, but suppressed their effects on StAR/progesterone. Treatment with activin A, B, or AB induced the phosphorylation of SMA- and MAD-related proteins (SMAD2 and 3), whereas activin AC had no such effects. Furthermore, co-culture of activin AC (1-100 ng/mL) with activin A (25 ng/mL) did not alter the effects of activin A on P450 aromatase or StAR mRNA levels.

CONCLUSION

Activin A, B, and AB have similar effects on steroidogenesis in human granulosa cells. In contrast, activin AC is not biologically active and does not act as a competitive antagonist.

CLIPPERS among patients diagnosed with non-specific CNS neuroinflammatory diseases

Chronic Lymphocytic Inflammation with Pontine Perivascular Enhancement Responsive to Steroids (CLIPPERS) is an inflammatory CNS disorder characterized by 1) subacute onset of cerebellar and brainstem symptoms, 2) peripontine contrast-enhancing perivascular lesions with a "salt-and-pepper" appearance on MRI, and 3) angiocentric, predominantly T-lymphocytic infiltration as revealed by brain biopsy. Inflammatory diseases including neuroinfections, CNS lymphoma and neurosarcoidosis must be excluded. Since CLIPPERS was described in 2010, many patients might have been misdiagnosed in the past. We therefore searched medical records from a large tertiary neurological center, the Department of Neurology at Rigshospitalet, Copenhagen University Hospital, for patients discharged between 1999 and 2013 with a diagnosis of "sarcoidosis with other localization", "other acute disseminating demyelination", "other demyelinating disease in the CNS" or "encephalitis, myelitis or encephalomyelitis". Of 206 identified patients, 24 had been examined by brain biopsy and were included for further evaluation. Following clinical, neuroradiological and neuropathological review, 3 patients (12.5%) were reclassified as having CLIPPERS. Median long-term follow-up was 75 months. The present results suggest that clinical re-evaluation of patients previously diagnosed with unspecified inflammatory demyelinating CNS disease or atypical neurosarcoidosis may increase the detection rate of CLIPPERS. Further, potentially severe neurological deficits and progressive parenchymal atrophy on MRI may suggest neurodegenerative features, which emphasizes the need for early immunomodulatory treatment.

BMP15 suppresses progesterone production by down-regulating StAR via ALK3 in human granulosa cells

In addition to somatic cell-derived growth factors, oocyte-derived growth differentiation factor (GDF)9 and bone morphogenetic protein (BMP)15 play essential roles in female fertility. However, few studies have investigated their effects on human ovarian steroidogenesis, and fewer still have examined their differential effects or underlying molecular determinants. In the present study, we used immortalized human granulosa cells (SVOG) and human granulosa cell tumor cells (KGN) to compare the effects of GDF9 and BMP15 on steroidogenic enzyme expression and investigate potential mechanisms of action. In SVOG cells, neither GDF9 nor BMP15 affects the mRNA levels of P450 side-chain cleavage enzyme or 3β-hydroxysteroid dehydrogenase. However, treatment with BMP15, but not GDF9, significantly decreases steroidogenic acute regulatory protein (StAR) mRNA and protein levels as well as progesterone production. These suppressive effects, along with the induction of Sma and Mad-related protein (SMAD)1/5/8 phosphorylation, are attenuated by cotreatment with 2 different BMP type I receptor inhibitors (dorsomorphin and DMH-1). Furthermore, depletion of activin receptor-like kinase (ALK)3 using small interfering RNA reverses the effects of BMP15 on SMAD1/5/8 phosphorylation and StAR expression. Similarly, knockdown of ALK3 abolishes BMP15-induced SMAD1/5/8 phosphorylation in KGN cells. These results provide evidence that oocyte-derived BMP15 down-regulates StAR expression and decreases progesterone production in human granulosa cells, likely via ALK3-mediated SMAD1/5/8 signaling. Our findings suggest that oocyte may play a critical role in the regulation of progesterone to prevent premature luteinization during the late stage of follicle development.

Overexpression of wild-type but not C134W mutant FOXL2 enhances GnRH-induced cell apoptosis by increasing GnRH receptor expression in human granulosa cell tumors

The etiology of granulosa cell tumors (GCTs) is largely unknown. The primary mode of treatment is surgical, however not all women are cured by surgery alone. Thus, it is important to develop improved treatments through a greater understanding of the molecular mechanisms that contribute to this disease. Recently, it has been shown that a FOXL2 402C>G (C134W) mutation is present in 97% of human adult-type GCTs, suggesting an important role for this mutation in the development of GCTs. We have shown previously that gonadotropin-releasing hormone (GnRH)-I and -II induce apoptosis in cultured normal human granulosa cells. Moreover, it has been reported that FOXL2 can bind to the promoter of the mouse GnRH receptor gene and regulate its transcription. Thus, we hypothesized that C134W mutant FOXL2 could modulate the pro-apoptotic effects of GnRH via aberrant regulation of GnRH receptor levels. Using KGN cells, a human GCT-derived cell line which harbors the FOXL2 402C>G mutation, we show that treatment with GnRH-I and -II induces cell apoptosis, and that small interfering RNA-mediated depletion of GnRH receptor abolishes these effects. Overexpression of wild-type FOXL2 increases both mRNA and protein levels of GnRH receptor and consequently enhances GnRH-induced apoptosis. Importantly, neither the expression levels of GnRH receptor nor GnRH-induced apoptosis were affected by overexpression of the C134W mutant FOXL2. Interestingly, knockdown of endogenous FOXL2 down-regulates GnRHR expression in normal human granulosa cells with wild-type FOXL2, but not in KGN cells. These results suggest that the FOXL2 402C>G mutation may contribute to the development of human adult-type GCTs by reducing the expression of GnRH receptor, thus conferring resistance to GnRH-induced cell apoptosis.

Hypoxia-inducible factor 1 alpha mediates epidermal growth factor-induced down-regulation of E-cadherin expression and cell invasion in human ovarian cancer cells

Hypoxia-inducible factor 1α (HIF-1α) regulates the transcription of a number of genes under hypoxia and other extracellular stimulations. It has been shown that E-cadherin is down-regulated by epidermal growth factor receptor (EGF) stimulation, and that cells with low E-cadherin expression are more invasive. Our recent study demonstrated a novel mechanism by which EGF down-regulates E-cadherin expression through production of hydrogen peroxide (H(2)O(2)) and the activation of p38 MAPK in human ovarian cancer cells. In this study, we were interested in examining the potential role of HIF-1α in cell invasion under normoxic conditions, specifically when cells are treated with EGF, which is known to down-regulate E-cadherin and increase invasiveness. We show that EGF treatment induces HIF-1α expression in two human ovarian cancer cell lines (SKOV3 and OVCAR5), and that this effect is diminished by treatment with a membrane-permeable H(2)O(2) scavenger, PEG-catalase. However, the induction of HIF-1α by EGF did not require the activation of p38 MAPK. Treatment with siRNA targeting HIF-1α reduces both basal and EGF-induced HIF-1α levels. Importantly, treatment with HIF-1α siRNA diminishes the up-regulation of Snail and Slug as well as the down-regulation of E-cadherin by EGF. The involvement of HIF-1α in the down-regulation of E-cadherin was confirmed with cobalt chloride (CoCl(2)), a hypoxia-mimetic reagent. Finally, we also show that EGF-induced cell invasion is attenuated by treatment with HIF-1α siRNA. This study demonstrates an important role for HIF-1α in mediating the effects of EGF on Snail, Slug and E-cadherin expression as well as invasiveness in human ovarian cancer cells.

The human gonadotropin-inhibitory hormone ortholog RFamide-related peptide-3 suppresses gonadotropin-induced progesterone production in human granulosa cells

RFamide-related peptide-3 (RFRP-3), a mammalian ortholog of avian gonadotropin-inhibitory hormone, has pronounced inhibitory effects on reproduction in a number of species. RFRP-3 suppresses gonadotropin release at the hypothalamic and/or pituitary levels; however, increasing evidence also suggests putative functions within the ovary. We have now demonstrated the expression of both RFRP and its receptor (GPR147) in primary cultures of human granulosa-lutein cells. Immunohistochemical analysis of normal human ovaries from premenopausal women showed that RFRPs and GPR147 were primarily localized in the granulosa cell layer of large preovulatory follicles as well as in the corpus luteum. Treatment of human granulosa-lutein cells with RFRP-3 reduced FSH-, LH- and forskolin-stimulated progesterone production and steroidogenic acute regulatory protein expression but did not affect basal or 8-bromoadenosine 3'5'-cyclic monophosphate stimulated levels. In addition, RFRP-3 inhibited gonadotropin- and forskolin-induced intracellular cAMP accumulation, and these effects were abolished by pretreatment with an inhibitor of inhibitory G(i/o) proteins (pertussis toxin). Importantly, the effects of RFRP-3 on FSH-, LH-, and forskolin-induced cAMP and progesterone accumulation were completely eliminated by cotreatment with the bifunctional GPR147/GPR74 antagonist RF9 or by pretreatment with GPR147 small interfering RNA. These results suggest that RFRP-3 is expressed in human granulosa cells in which it acts via its receptor, GPR147, to inhibit gonadotropin signaling at the level of adenylyl cyclase via activation of a pertussis toxin-sensitive Gα(i/o) protein. This leads to reduced gonadotropin-stimulated cAMP accumulation and progesterone synthesis, likely via reduced steroidogenic acute regulatory protein expression. Thus, ovarian RFRP-3/GPR147 signaling could contribute to normal ovarian function.