Trophoblast function is altered by decidual factors in gestational-dependant manner

Inadequate implantation and placentation is associated with miscarriage and placental insufficiency. The decidual environment is thought to regulate trophoblast invasion, however this is poorly defined in humans. We aimed to determine the effect of decidualization on trophoblast function. In vitro decidualized primary human endometrial stromal cells (HESC) significantly enhanced first-trimester extravillous trophoblast (EVT) (6-8-weeks gestation) adhesion, outgrowth/invasion. In EVTs from 10 to 12-weeks gestation this effect was absent (adhesion, invasion) or reversed (outgrowth). HESC conditioned media had no effect on trophoblast MMP9 production/activity. Decidualization regulated EVT function in a gestational-dependent manner. This study highlights the importance of trophoblast-decidual synchrony.

Interleukin-11 up-regulates endoplasmic reticulum stress induced target, PDIA4 in human first trimester placenta and in vivo in mice

Interleukin (IL)11 is a crucial factor for human trophoblast function and placentation. Elevated levels are associated with pregnancy complications including preeclampsia, intrauterine growth restriction (IUGR) and preterm birth. However, the regulation of IL11 in the placenta has not been investigated. We examined the effect of pro-inflammatory cytokines IL1β and TNFα, as well as low oxygen tension (2%) on IL11 levels in first trimester placental villous explants. IL1β upregulated IL11 mRNA and protein, while TNFα and low oxygen had no effect. Using mass spectrometry, we identified protein disulfide isomerase 4 (PDIA4) in IL11-treated first trimester human placental explants (100 ng/ml, 24 h, n = 3), but not PBS control tissues. PDIA4 is a member of the PDI family, also known as endoplasmic reticulum (ER) stress protein (ERP)72. We previously identified GRP78 (a master regulator for ER stress) in human placenta for the first time and demonstrated that IL11 up-regulates GRP78 in the placenta. In this report, we demonstrated that IL11 upregulates PDIA4 protein in human placental villous tissue, HTR8-SVneo trophoblasts (cell line) and in vivo in IL11-treated mouse placenta. We aimed to determine whether IL11 upregulates other ER stress proteins in human first trimester placental villous. IL11 stimulated ERP44, but not GRP94, or PDI. Placental endoplasmic reticulum stress has been postulated in the pathophysiology of preeclampsia and IUGR, but its activation remains elusive. Together, these data suggest that IL11 could trigger an ER stress response in the placenta, which may contribute to obstetric complications such as preeclampsia.

Human extravillous trophoblast invasion: intrinsic and extrinsic regulation

During the establishment of pregnancy, a human blastocyst implants into the uterine endometrium to facilitate the formation of a functional placenta. Implantation involves the blastocyst adhering to the uterine luminal epithelium before the primitive syncytiotrophoblast and subsequently specialised cells, the extravillous trophoblast (EVT), invade into the decidua in order to engraft and remodel uterine spiral arteries, creating the placental blood supply at the end of the first trimester. Defects in EVT invasion lead to abnormal placentation and thus adverse pregnancy outcomes. The local decidual environment is thought to play a key role in regulating trophoblast invasion. Here we describe the major cell types present in the decidua during the first trimester of pregnancy and review what is known about their regulation of EVT invasion. Overall, the evidence suggests that in a healthy pregnancy almost all cell types in the decidua actively promote EVT invasion and, further, that reduced EVT invasion towards the end of the first trimester is regulated, in part, by the reduced invasive capacity of EVTs shown at this time.

Detection of TMPRSS2-ERG fusion gene in benign prostatic hyperplasia

The Ets-related gene fusions are among the most common molecular alterations in prostate cancer (PCa) and are detected in more than 50 % of PCas. Transmembrane protease serine 2 and Ets-related gene fusion (TMPRSS2-ERG) is the most frequently identified chimeric gene and has been associated with undifferentiated and invasive phenotypes. TMPRSS2-ERG has also been detected in prostate intraepithelial neoplasia (PIN) lesions and more rarely in benign prostatic hyperplasia (BPH) regions mainly in PCa-bearing glands. The possibility that the fusion TMPRSS2-ERG may be present in BPH samples in the absence of apparent PCa was addressed. Out of 115 BPH samples, three were found positive employing RT-PCR. The presence of the fusion gene was confirmed by FISH for these samples, and an additional four samples were found to carry the TMPRSS2-ERG fusion out of 43 tested by the later approach. The presence of the TMPRSS2-ERG fusion did not result in altered expression of 12 putative downstream targets. These findings indicate that TMPRSS2-ERG may or may not lead to PCa development.

The role of leukemia inhibitory factor in tubal ectopic pregnancy

INTRODUCTION

Ectopic pregnancy is unique to humans and a leading cause of maternal morbidity and mortality. The etiology remains unknown however factors regulating embryo implantation likely contribute. Leukemia inhibitory factor (LIF) has roles in extravillous trophoblast adhesion and invasion and is present in ectopic implantation sites. We hypothesised that LIF facilitates blastocyst adhesion/invasion in the Fallopian tube, contributing to ectopic pregnancy.

METHODS

We immunolocalised LIF receptor (R) in tubal ectopic pregnancy (N = 5). We used an oviduct cell line (OE-E6/E7) to model Fallopian tube epithelial cells and a trophoblast spheroid co-culture model (HTR-8/SVneo cell line formed spheroids) to model blastocyst attachment to the Fallopian tube. We examined LIF signaling pathways in OE-E6/E7 cells by Western blot. The effect of LIF and LIF inhibition (using a novel LIF inhibitor, PEGLA) on first-trimester placental outgrowth was determined.

RESULTS

LIFR localised to villous and extravillous trophoblast and Fallopian tube epithelium in ectopic pregnancy. LIF activated STAT3 but not the ERK pathway in OE-E6/E7 cells. LIF stimulated HTR-8/SVneo spheroid adhesion to OE-E6/E7 cells which was significantly reduced after PEGLA treatment. LIF promoted placental explants outgrowth, while co-treatment with PEGLA blocked outgrowth.

DISCUSSION

Our data suggests LIF facilitates the development of ectopic pregnancy by stimulating blastocyst adhesion and trophoblast outgrowth from placental explants. Ectopic pregnancy is usually diagnosed after 6 weeks of pregnancy, therefore PEGLA may be useful in targeting trophoblast growth/invasion.

CONCLUSION

LIF may contribute to the development of ectopic pregnancies and that pharmacologically targeting LIF-mediated trophoblast outgrowth may be useful as a treatment for ectopic pregnancy.

The chrondroitin sulfate proteoglycan (CSPG4) regulates human trophoblast function

INTRODUCTION

Trophoblast growth and invasion of the uterine endometrium are critical events during placentation and are tightly regulated by locally produced factors. Abnormal placentation can result in early miscarriage or preeclampsia and intrauterine growth restriction, leading to impaired fetal and/or maternal health. Chondroitin sulfate proteoglycan 4 (CSPG4) is involved in cancer cell migration and invasion, processes which are critical during placentation but unlike in cancer, trophoblast invasion is highly regulated. CSPG4 expression and function in trophoblast is unknown. We determined CSPG4 expression in human first trimester placenta and implantation sites, and investigated whether CSPG4 influenced proliferation, migration and invasion of a human extravillous trophoblast (EVT) cell line (HTR8/SVneo cells) as a model for extravillous trophoblast (EVT).

METHODS AND RESULTS

Immunoreactive CSPG4 localized to EVT cells in the trophoblast shell, subpopulations of interstitial EVT cells within the decidua and cytotrophoblast cells in placental villi. In HTR8/SVneo cells, siRNA knockdown of CSPG4 stimulated proliferation and decreased migration/invasion. In primary first trimester placental villi explants two cytokines, interleukin 11 (IL11) and leukemia inhibitory factor (LIF) with known roles in trophoblast function, stimulated CSPG4 mRNA expression and immunoreactive protein in the cyotrophoblast.

DISCUSSION AND CONCLUSION

This is the first demonstration of the production and function of CSPG4 in human placentation. These data suggest that locally produced CSPG4 stimulates human EVT migration and invasion and suggests that IL11 and LIF regulate villous cytotrophoblast differentiation towards the invasive phenotype at least in part via CSPG4.

Pancreatic pseudocyst in a child due to blunt andominal trauma during a football game

Pancreatic pseudocyst in children due to abdominal trauma is a rare entity. We report a 14-year-old boy suffering from acute pancreatitis due to blunt abdominal trauma that occurred during a football game, and resulted in a large pseudocyst formation. The child was treated conservatively for the post traumatic acute pancreatitis for 4 weeks and thereafter he was followed up for another 2 weeks. At the end of the 6 weeks after the first insult, the child underwent an open cystgastrostomy. Postoperative course was uneventful and the child was discharged on the 6(th) postoperative day.

153. COMBINATION METHOTREXATE AND EPIDERMAL GROWTH FACTOR RECEPTOR INHIBITION AS A NOVEL MEDICATION-BASED CURE OF ECTOPIC PREGNANCIES

Ectopic pregnancies are serious gynaecological emergencies that can cause fatal haemorrhage. Most are treated surgically. Given the placenta is heavily reliant on Epidermal Growth Factor Receptor (EGFR) signaling, we set out to develop a medication-based treatment of ectopics using combination gefitinib (EGFR inhibitor) and methotrexate (folate antagonist). Both drugs are well tolerated and available in tablet form. We used in vitro and in vivo approaches to test the ability of gefitinib and methotrexate to regress placental tissue, and to explore molecular mechanisms. In vitro assays included immunohistochemistry (EGFR staining) western blot (EGFR phosphorylation), cell viability assays (Cell-Titre Blue, LDH cytotoxicity assay, xCELLigence system), apoptosis assays (PCR, FACS of M30 antibody) and The Bioplex Platform (phosphorylation of the EGFR pathway). JEG-3 xenografts were used to assess regression of placental tissue in vivo, where serum hCG was also measured (ELISA). EGFR was highly expressed in placentae from ectopic pregnancies. Combination treatment was supra-additive in inducing cell death of placental tissue in vitro, with >70% cell death by 48 hours (Syncytialised BeWos, JEG-3 and 1st trimester trophoblast). This supra-additive effect was demonstrated in both end point assays (cell viability) and regular monitoring using The xCELLigence system. Gefitinib potently blocks EGFR phosphorylation in placental tissues in vitro (Western blot). Both drugs may be converging to inhibit Akt phosphorylation (Bioplex analysis). Combination treatment increases apoptosis (FACS of M30 antibody). In vivo, Gefitinib or MTX as single agents induced significant decrease in xenograft tumour volume in a dose dependent manner (n ≤ 5 mice per treatment). However, combining these drugs was supra-additive in decreasing xenograph tumour volume and weight. Serum hCG in mice was lowest with combination treatment. Combination gefitinib and methotrexate potently regresses placental tissue. It may be a novel therapeutic approach to cure ectopic pregnancies, potentially replacing surgery with tablets.

152. DEVELOPMENT OF A VAGINALLY APPLIED, NON-HORMONAL CONTRACEPTIVE: THE CONTRACEPTIVE EFFICACY AND IMPACT ON BONE TURNOVER OF PEGLA, A LONG-ACTING LIF ANTAGONIST

The WHO has called for the urgent development of pharmacological, non-hormonal contraceptives. Leukaemia inhibitory factor (LIF) is obligatory for embryo implantation in mice and associated with infertility in women. Injection of a long-acting LIF antagonist (PEGLA) blocks uterine LIF, preventing implantation in mice, making PEGLA a promising non-hormonal contraceptive. LIF and LIFR null mice show decreased bone volume associated with increased osteoclast number and size, suggesting PEGLA may target bone. Vaginally administered PEGLA could be a ‘dual-role’ contraceptive: delivered in a microbicide which blocks the vaginal transmission of sexually transmitted infections. We aimed to establish the contraceptive efficacy of vaginally administered PEGLA and identify non-uterine targets of PEGLA in mice. PEGLA was administered to mated female mice by intraperitoneal (IP) injection or vaginally (n = 4/group) during the peri-implantation period to determine its effect on implantation and bone turnover. The tissue and blood accumulation of 125I-PEGLA or control was identified at various time-points following IP injection (≤120 h) or vaginal administration (≤24 h) (n = 3/group). PEGLA administered via vaginal gel blocked implantation (0.0+0.0 vs 8.5+0.5) at a lower dose (500 μg) than IP injection (1500 μg). PEGLA administered by IP injection resulted in fewer (4.0+0.3% vs 7.7+1.5%; P < 0.05) but larger (20.9+0.9 μm vs 18.1+0.5 μm; P < 0.05) osteoclasts and increased trabecular bone volume (6.8+0.9% vs 3.1+1.1%; P < 0.05) but vaginally administered PEGLA had no effect on bone (P > 0.05). 125 I-PEGLA accumulated more quickly (10 min vs 30 min) and was retained longer (96 h vs 24 h) in blood and tissue following IP injection compared to vaginal administration. This is the first study to show the contraceptive efficacy of a PEGylated compound following vaginal delivery. Local delivery of PEGLA decreased the required dose and eliminated the effect on bone, suggesting that local administration would minimise the non-target effects of PEGLA. Contraceptive trials are now required in non-human primates to progress PEGLA towards human clinical trials.

301. LEUKEMIA INHIBITORY FACTOR IS A CRITICAL REGULATOR OF DECIDUALIZATION OF ENDOMETRIAL STROMAL CELLS IN HUMANS AND MICE

Decidualization is the differentiation of endometrial stromal cells into decidual cells. It is a critical process in embryo implantation, placentation and the establishment of pregnancy. Inadequate decidualization can lead to infertility, abnormal placentation and recurrent miscarriage. Endometrial leukemia inhibitory factor (LIF) is indispensible in blastocyst implantation in mice and dysregulated in infertile women. LIF is produced by 1st trimester decidual cells but its role in decidualization is not known. This study aimed to examine the role of LIF in human and mouse decidualization. Primary human endometrial stomal cells (HESC) were isolated and decidualized (D) by treatment with estradiol (E) +medroxyprogesterone acetate (MPA) for 14 days. HESC were also treated with E+MPA+/–LIF (0.5, 5, 50, 100 and 200 ng/mL) for 14 days. Prolactin secretion was used to assess the extent of decidualization (n = 6). D and non-D HESC were also treated with LIF (0.5, 5, 50, 100 and 200 ng/mL +/– LIF inhibitor) for 15min and the phosphorylation (p) of signal transducer and activator of transcription (STAT)3/STAT3 abundance was detected by Western blot (n = 4). RNA was isolated for analysis of LIF and LIF receptor (R) mRNA expression during decidualization (n = 4). HESC treated with E+MPA+LIF (50, 100 and 200 ng/mL) secreted more prolactin compared to cells treated with E+MPA alone (P < 0.05). LIF increased pSTAT3/STAT3 abundance in D and non-D cells while LIF+LIF inhibitor abolished pSTAT3/STAT3. LIF mRNA was downregulated while LIF-R mRNA increased during decidualization. In vivo, mated mice (n = 5) were injected intraperitoneally with a unique long acting LIF inhibitor post-implantation at day 4.5 of pregnancy and resulted in reduced decidualization compared to control. This is the first study to demonstrate that LIF promoted decidualization of HESC possibly via pSTAT3. It further suggested that LIF regulated decidualization in mice demonstrating a newly identified critical role for LIF in the establishment of pregnancy.

004. A NEW ERA IN CONTRACEPTIVE DEVELOPMENT: NON-HORMONAL OPTIONS THAT ALSO TARGET SEXUALLY TRANSMITTED INFECTIONS

Despite huge increases in access to contraceptives globally more than 700 000 maternal deaths related to unintended pregnancies occurred between 1995 and 2000 mostly in developing countries. Over 80 million women have unintended or unwanted pregnancies annually. Remarkably, there have been no new methods of contraceptives developed in the last 50 years. The extremely high incidence of sexually transmitted infections (STIs) indicates that it is desirable to develop contraceptives that also target STIs. Two interleukin (IL) 6-type cytokines, leukemia inhibitory factor (LIF) and IL11, are obligatory for implantation in mice and are dysregulated in endometrium of some women with infertility. Both LIF and IL11 are also thought to have roles in Chlamydia-induced inflammation which can lead to a multitude of pathologies. LIF and IL11 antagonists were produced and their contraceptive efficacy tested in mice. Polyethylene glycol (PEG) was conjugated to LIF antagonist (LA) or IL11 antagonist (IL11A) to increase their serum half-life. PEGLA injected during the peri-implantation period blocked LIF action in the endometrium and totally prevented embryo implantation while having no embryo toxic effects.1 Similarly, injection of PEGIL11A blocked decidua formation resulting in pregnancy failure.2 In women, vaginally administered drugs preferentially localise to the uterus suggesting that vaginal administration of PEGLA is an appropriate delivery method for contraceptive purposes. Further, vaginally administered PEGLA may be useful as a ‘dual-role’ contraceptive to also block STIs. PEGLA administered via vaginal gel was shown to prevent implantation having minimal effects on non-uterine LIF targets. This is the first study to show the contraceptive efficacy of a PEGylated compound delivered vaginally. It further indicates that PEGLA may be useful as a dual-role contraceptive. Contraceptive trials in non-human primates are currently underway to determine the effect of PEGLA on implantation. If effective, this will offer new opportunities as pharmacological, non-hormonal dual-role contraceptives for women. (1) White CA, Zhang JG, Salamonsen LA, Baca M, Fairlie WD, Metcalf D, Nicola NA, Robb L, Dimitriadis E (2007) Proc Natl Acad Sci USA 104: 19 357–62.(2) Menkhorst E, Salamonsen LA, Robb L, Dimitriadis E (2009) Biol of Reprod 80: 920–927.

Interleukin-11 and leukemia inhibitory factor regulate the adhesion of endometrial epithelial cells: implications in fertility regulation

Embryo implantation requires the closely harmonized processes of apposition, attachment, and adhesion of the conceptus to the maternal endometrial epithelium. IL-11 and leukemia inhibitory factor (LIF), two IL-6 family cytokines, are produced by the endometrium and are absolutely required for implantation in mice. We examined the effect of IL-11 and LIF on human endometrial epithelial cell adhesion. Both cytokines increased adhesion of primary human endometrial epithelial cells to fibronectin and collagen IV. IL-11 stimulated, whereas LIF had no effect on the adhesion of trophoblast to endometrial epithelial cells. Focused oligogene arrays were used to identify extracellular matrix and adhesion molecules mRNAs regulated by endometrial epithelial cells. We demonstrated by real-time RT-PCR and antibody arrays that both cytokines increased integrin-alpha2 mRNA and protein by endometrial epithelial cells. Signal transducers and activators of transcription (STAT)-3 inhibition reduced IL-11- and LIF-mediated epithelial cell adhesion to fibronectin, suggesting both cytokines regulated adhesion via phosphorylation of STAT3. Addition of either IL-11 neutralizing antibody and IL-11 or LIF and LIF antagonist to endometrial epithelial cells abolished cytokine induced phosphorylated STAT3. LIF but not IL-11 induced adhesion to collagen IV was reduced by an integrin-alpha2beta1 neutralizing antibody. This study demonstrated that IL-11 and LIF regulated endometrial epithelial cell adhesion, suggesting that targeting IL-11 and LIF may be useful in regulating fertility by either enhancing or blocking implantation.

172. DEVELOPMENT OF A NON-HORMONAL CONTRACEPTIVE: VAGINAL DELIVERY OF A LIF INHIBITOR: ITS TISSUE DISTRIBUTION AND EFFECT ON IMPLANTATION IN MICE

Uterine leukaemia inhibitory factor (LIF) is obligatory for fertility in mice and associated with infertility in women. Intraperitoneal injection (IPI) of a long-acting LIF inhibitor conjugated to polyethylene glycol (PEGLA) blocks endometrial LIF action preventing implantation1. Thus, PEGLA is a promising non-hormonal contraceptive. In women, vaginally applied (VA) compounds preferentially localize to the uterus suggesting a desirable delivery method for contraceptive purposes; however this has not been examined in mice. We aimed to compare the effects of VA and IPI PEGLA on tissue distribution and implantation in mice. Non-pregnant or mated female mice (Pregnant day [D] 2 [D0: day of plug], n=3/group) were given 125I-PEGLA by IPI (3x106cpm) or VA (7x105cpm). 125I-PEGLA was measured in blood and tissue at various time points. To block implantation, mated mice (n=4/group) were given PEGLA or control by IPI (500μg/injection) or VA (300μg/injection) at 1200h and 2200h on D2 and 1000h on D3 and the uterus examined for implantation sites on D6. 125 I-PEGLA accumulated in blood and uterus following IPI more rapidly (10min cf 30min), reached a higher concentration (10min, 6h and [blood] 24h; p<0.05) and remained longer (24h cf 6h) compared to VA. The percentage of protein-bound 125I in blood was higher following IPI (79.4+1.9%) than VA (47.5+6.7%) at 6h (p<0.05). Following IPI, 125I-PEGLA accumulated in the liver, gall bladder and stomach (2h) and spleen (24h) compared to control while no specific tissue accumulation was observed following VA. PEGLA prevented implantation following IPI (p<0.05) and reduced the size of implantation sites and decidualization in VA compared to controls. This study demonstrated differences in tissue distribution between VA and IPI PEGLA. It showed that VA PEGLA acted on the uterus in mice albeit to a lesser extent than IPI. It suggests that VA PEGLA is a potential route of delivery for contraceptive purposes.

525. ROLES FOR HUMAN CHORIONIC GONADOTROPHIN IN EMBRYO-ENDOMETRIAL CROSS-TALK DURING BLASTOCYST IMPLANTATION

Emerging evidence suggests an important role for the early embryo product human chorionic gonadotrophin (hCG) in embryo-endometrial interactions critical for successful embryo implantation1. The human endometrium is also a source of hCG, with maximal expression of hCG and its receptor, hCG/LHR, in endometrial epithelial cells during the window of implantation in vivo2,3, and in primary endometrial epithelial cells (EECs)3. Implantation is tightly regulated by growth and regulatory factors produced within the embryo-endometrial microenvironment. We hypothesise that embryo/endometrial-derived hCG mediates the molecular cross talk vital for successful implantation. The main objective of this study was to investigate the effect of hCG on the production of a selected cohort of 42 cytokines and growth factors by EECs. These included those with both known and previously unidentified roles during implantation. The secretory profile of cytokines/growth factors produced by EECs was also analysed. EECs (n=8 cultures) were isolated from biopsies collected from fertile cycling women. Cells were treated without or with recombinant hCG for 48 hr and conditioned media collected for quantitative analysis using LuminexTM multiplex technology. For the first time, a secretory profile of 42 cytokines and growth factors produced by EECs was established, as was the identification of fibroblast growth factor-2 (FGF-2) secretion by human endometrial epithelium. hCG (2 IU/ml) significantly increased the production of a number factors including those with known roles during trophoblast migration and adhesion (CX3CL1; 71±31%, CXCL10; 67±24%, CCL4; 87±12%), in trophoblast differentiation (IL-1α ; 68±31%) and with unidentified roles during implantation (CCL22; 78±40%, GM-CSF; 45±16%, FGF-2; 50±25%; all p<0.05). Upregulation of the known hCG regulated proteins, VEGF and LIF, validated this study. These findings clearly support roles for the embryo/endometrium via hCG in actively contributing to the molecular cross-talk during the early stages of implantation.

107. INTERLEUKIN 11 AND LEUKEMIA INHIBITORY FACTOR REGULATE CYTOKINE NETWORKS IN HUMAN FIRST TRIMESTER PLACENTA

Inadequate trophoblast invasion is thought to be involved in the pathogenesis of preeclampsia (PE). Shallow trophoblast invasion has been implicated to lead to placental hypoxia and a localised overproduction of pro-inflammatory cytokines. Interleukin (IL) 11 and leukemia inhibitory factor (LIF) are IL6-type cytokines produced at the maternal-fetal interphase and regulate human trophoblast migration/invasion, but their mechanisms of action are unknown. We aimed to determine the effect of hypoxia on human placental IL11/LIF secretion and the effect of IL11/LIF on placental cytokine secretion. As an in vitro model we cultured human first trimester placental villous explants (gestation weeks 7-9) in serum free conditions under either 2% (hypoxia) or 20% oxygen (normoxia) (N=8/gp) for 48h. Medium was assayed for IL11/LIF by ELISA. The effect of IL11/LIF (N=6/gp) on placental explant cytokine secretion (26 cytokines) was analysed using a quantitative multiplex immunoassay. Data was expressed as pg/mg wet weight and then as % change vs control (100%). IL11 secretion from explants was decreased by 76±5% (p<0.01) under hypoxia vs normoxia while LIF secretion did not differ significantly. Under normoxia the most highly abundant cytokines were IL6, IL8 and MCP-1 while moderate levels of G-CSF, CX3CL1, IP-10, and PGDF were present in conditioned medium. IL11 increased IL10 secretion while it decreased G-CSF, TNFa, IL1receptor antagonist (Ra), IL6 and PDGF secretion (p<0.05) vs control. Similarly LIF decreased G-CSF, TNFa, IL1Ra and additionally IL8 secretion (p<0.05) vs control. IL6 and VEGF secretion were increased (p<0.05) while MCP-1 was reduced (p<0.05) by hypoxia vs normoxia. This study identified for the first time that IL11 was reduced by hypoxia and identified a profile of cytokines secreted by placenta. IL11 and LIF regulated similar and unique anti-inflammatory cytokines in first trimester placenta. Whether placental IL11 or LIF is altered in women with PE remains to be elucidated however this study suggests mechanisms of action and confirms the importance of IL11/LIF in placentation.

414. The contraceptive potential of a long-acting IL-11 inhibitor

Interleukin 11 (IL-11) signalling is essential for the establishment of pregnancy in mice, through its action on the differentiation of uterine endometrial stromal cells (decidualisation), a critical process during embryo implantation. IL-11Rα deficient mice are infertile due to defective decidualisation1. IL-11 expression peaks between days (D) 4.5–9.5 of pregnancy (D0: day of plug) in mouse decidua. We examined the effect of administering (intraperitoneal [IP] injection or vaginal gel) a PEGylated IL-11 antagonist (PEGIL-11A) on decidualisation and pregnancy outcome in mice. The sera half-life of PEGIL-11A (IC50 2.8nM) following IP injection was 24h, compared with <1 h for the non-PEGylated antagonist (IC50 0.26nM). Following IP injection, PEGIL-11A localised to decidual cells and blocked the IL-11 decidual target protein, cyclin D3. IP injection of 600µg/application PEGIL-11A (or PEG control) at 1000 h and 1600 h on D3 and 1000 h on D4 (n = 4/group), resulted in smaller implantation sites than controls on D6 due to retarded mesometrial decidual formation. On D10, severe decidual destruction was visible: implantation sites contained regions of haemorrhage and the uterine luminal epithelium had reformed, suggesting a return to oestrous cycling. Following vaginal application in aqueous placebo gel, PEGIL-11A localised to decidual cells. Vaginal application of 200µg/application PEGIL-11A (or control) twice daily from D2 to D5 (n = 4/group), resulted in smaller implantation sites than controls on D6 due to partial inhibition of mesometrial decidual formation. This study demonstrates that PEGIL-11A blocked IL-11 action in the uterus, resulting in total pregnancy loss, equivalent to the IL-11Rα deficient mouse. In women, IL-11 and its receptor are produced by the uterine luminal and glandular epithelium during the period of uterine receptivity2, suggesting that IL-11 may act during initial blastocyst attachment to the luminal epithelium as well as stromal decidualisation. This study provides proof-of-principle for the development of a novel, non-hormonal contraceptive for women. (1) Robb L et al. Nature Medicine 1998; 4: 303–308. (2) Dimitriadis E et al. Molecular Human Reproduction 2000; 6: 907–914.

216. Activin A regulates trophoblast cell adhesion: implications for uterine receptivity and embryo implantation

Embryo implantation involves blastocyst attachment to the endometrial luminal epithelium, followed by trophoblast invasion. This process involves a coordinated crosstalk between the implanting blastocyst and the endometrium. Adhesion molecules play an instrumental role during implantation and are regulated by a variety of factors including cytokines and growth factors. Activin A, a TGF-β superfamily member, has been detected in uterine washings,1 and its subunit, β A, is produced by endometrial glands during the secretory phase of the menstrual cycle.2 In endometriosis, a disease that associated with sub-fertility, β A immunostaining is increased in endometrial glands,3 suggesting higher levels of activin A secreted into the uterine lumen could contribute to sub-fertility observed in endometriosis. Therefore we hypothesised that activin A secretion into the uterine cavity affects the adhesive properties of the cells present at the maternal-fetal interface. The aims of the study were to measure and compare activin A secretion in uterine washings from women with and without endometriosis and to demonstrate whether activin A regulates adhesion to extracellular matrix (ECM) components. Uterine washings (5 mL of sterile saline) were collected from women with and without endometriosis during the secretory phase. Activin A was measured by ELISA. HTR8 (human trophoblast cell-line) cells were treated with rhActivin A (50 ng/mL) and assessed for binding to fibronectin, laminin, vitronectin, collagen I and IV. Activin A (>10pg/mL) was detectable in uterine washings from women with and without endometriosis and levels were elevated in endometriosis patients. Untreated HTR8 cells adhered maximally to fibronectin, collagen I and collagen IV with low binding to vitronectin and laminin. Following activin treatment, HTR8 cell binding to fibronectin, collagen I and IV was significantly decreased (n = 3, P < 0.05). These results suggest that activin A regulates the adhesive properties of the blastocyst during implantation. This study also implies that abnormalities in local activin A levels during endometrial receptivity may contribute to sub-fertility in women. (1) Petraglia et., al. (1998) J Clin Endocrinol Metab. (2) Jones et., al. (2000) Mol Hum Reprod. (3) Rombauts et., al. (2006) Aust N Z J Obstet Gynaecol.

223. Interleukin-11 inhibits human trophoblast invasion via STAT-3 and not MAPK, indicating a likely role in the decidual restraint of trophoblast invasion during placentation

Successful pregnancy depends on the precise regulation of extravillous trophoblast (EVT) invasion into the uterine decidua, primarily by decidua-derived factors. In humans, during early pregnancy, interleukin (IL)-11 is maximally expressed in the decidua1, with its receptor, IL-11-receptor α (Rα) also identified on invasive EVT in vivo2. While a role for IL-11 in EVT migration has been established2, whether it also plays a role in regulating EVT invasion is unknown. We investigated whether IL-11 influences human EVT invasion and the signalling pathways and underlying mechanisms involved using the HTR-8/SVneo immortalised EVT cell-line and primary EVT as models for EVT. The effect of IL-11 on tyrosine phosphorylation (p) of signal transducer and activator of transcription (STAT)-3 was determined by Western Blot. EVT invasion was assessed using in vitro Matrigel invasion assays. To elucidate the mechanisms by which IL-11 may influence EVT invasion, matrix metalloproteinase (MMP) and urokinase plasminogen activator (uPA) activity were assessed by gelatin and plasminogen zymography / uPA activity assay respectively. Tissue inhibitor of MMPs (TIMPs)-1 and –2, plasminogen activator inhibitor (PAI)-1 and –2 and uPA receptor (uPAR) were assessed by ELISA whereas TIMP-3 was assessed by Western Blot. EVT adhesive properties and integrin expression were assessed by in vitro adhesion assays. IL-11 (100 ng/mL) significantly inhibited invasion of EVT cells by 40–60% (P < 0.001). This effect was abolished by inhibitors of STAT-3 but not of mitogen-activated protein kinase pathways. IL-11 (100 ng/mL) had no effect on MMP-2 and –9, TIMP 1–3, uPA, uPAR, PAI-1 and –2 in EVT conditioned media and / or cell lysates. IL-11 (100 ng/mL) also did not regulate EVT cell adhesion or integrin expression. These data demonstrate that IL-11 inhibits human EVT invasion via STAT-3 indicating an important role for IL-11 in the decidual restraint of EVT invasion during normal pregnancy. (1) Dimitriadis et al. (2003) Reprod Biol Endocrinol. 1, 34–38 (2) Paiva et al. (2007) Endocrinol. 148, 5566–72

Facilitation of decidualization by locally produced ghrelin in the human endometrium

Ghrelin acting via the growth hormone secretagogue receptor (GHS-R) stimulates GH secretion from pituitary glands. Both ligand and receptor are present in the pituitary, hypothalamus and many peripheral tissues including the uterus. This study demonstrates the cyclical expression of GHS-R and ghrelin in human endometrium. mRNA and protein for ghrelin and GHS-R were examined using RT-PCR and immunohistochemistry. Both ghrelin and GHS-R mRNA levels were highest in the secretory phase, with lower levels in the mid-proliferative phase and even lower expression in the menstrual phase. Immunoreactive ghrelin and GHS-R were confined predominantly to glandular epithelial and stromal cells with the greatest intensity of staining in secretory phase samples, consistent with the RT-PCR data. Additionally, we examined ghrelins effect on the decidualization of human endometrial stromal cells (HESCs) combined with sex steroid and cAMP treatments using prolactin (PRL) and insulin-like growth factor binding protein-1 (IGFBP-1) production as markers of decidualization. Ghrelin administered in combination with sex steroids to HESC, resulted in an increase in PRL and IGFBP-1 production above that obtained with cAMP, or sex steroids alone (P<0.001) whereas ghrelin in combination with cAMP inhibits the action of cAMP. These findings have potential clinical applications for the regulation of fertility.

Interleukin-11 inhibits expression of insulin-like growth factor binding protein-5 mRNA in decidualizing human endometrial stromal cells

Differentiation of endometrial stromal cells into decidual cells is essential for successful embryo implantation. Interleukin (IL)-11 signalling is critical for normal decidualization in the mouse. The expression of IL-11 and its receptors during the menstrual cycle, and the effect of exogenous IL-11 on the decidualization of human endometrial stromal cells in vitro, suggests a role for this cytokine in human decidualization. As the downstream target genes of IL-11 are also likely to be critical mediators of this process, this study aimed to identify genes regulated by IL-11 in decidualizing human endometrial stromal cells in vitro. Stromal cells isolated from endometrial biopsies were decidualized with 17beta estradiol (E) and medroxyprogesterone acetate (EP) in the presence or absence of exogenous IL-11, and total RNA used for cDNA microarray analysis and real-time RT-PCR. Microarray analysis revealed 16 up-regulated and 11 down-regulated cDNAs in EP + IL-11-treated compared with EP-treated cells. The most down-regulated gene was insulin-like growth factor binding protein-5 (IGFBP-5) (3.6-fold). Using real-time RT-PCR, IL-11 was confirmed to decrease IGFBP-5 transcript abundance 102-fold (P = 0.016; n = 6). No difference in IGFBP-5 immunostaining intensity was detected in stromal cells decidualized in the presence or absence of IL-11, and there was no effect of exogenous IGFBP-5 on the progression of steroid-induced in vitro decidualization. Interactions between IL-11 and its target genes, including IGFBP-5, may contribute to the regulation of decidualization and/or mediate communication between the decidua and invading trophoblast at implantation.

Cytokines, chemokines and growth factors in endometrium related to implantation

The complexity of the events of embryo implantation and placentation is exemplified by the number and range of cytokines with demonstrated roles in these processes. Disturbance of the normal expression or action of these cytokines results in complete or partial failure of implantation and abnormal placental formation in mice or humans. Of known importance are members of the gp130 family such as interleukin-11 (IL-11) and leukaemia inhibitory factor (LIF), the transforming growth factor beta (TGFbeta) superfamily including the activins, the colony-stimulating factors (CSF), the IL-1 system and IL-15 system. New data are also emerging for roles for a number of chemokines (chemoattractive cytokines) both in recruiting specific cohorts of leukocytes to implantation sites and in trophoblast differentiation and trafficking. This review focuses on those cytokines and chemokines whose expression pattern in the human endometrium is consistent with a potential role in implantation and placentation and for which some relevant actions are known. It examines what is known of their regulation and action along with alterations in clinically relevant situations.

mRNA quantification and clinical evaluation of telomerase reverse transcriptase subunit (hTERT) in intracranial tumours of patients in the island of Crete

Telomerase is a reverse transcriptase that maintains telomeres by adding telomeric TTAGGG repeats to the ends of human chromosomes. The aim of this study was to evaluate quantitatively the mRNA expression of telomerase catalytic subunit (hTERT) in different types of intracranial tumours in relation to their histologic pattern and grade and correlate it with progression-free (PFS) and overall survival (OS) of patients. Human telomerase reverse transcriptase mRNA levels were estimated by the use of real time RT–PCR in 68 samples of intracranial tumours. It revealed statistical correlation between hTERT mRNA expression levels and the grade of the tumours (P<0.001). Patients having negative expression of hTERT mRNA had statistically longer PFS (P=0.031) and OS (P=0.047). Cox univariate regression analysis revealed that hTERT mRNA-positive patients had a high and statistically significant risk of relapse (hazard ratio (HR) of 2.24 and P=0.038). In the Cox multivariate regression model, the levels of hTERT mRNA were adjusted for tumour grade and patients age, and since there was statistically significant relationship between the levels of hTERT mRNA and the grade of the tumours (P=0.003 or P=0.006, respectively), hTERT mRNA levels could not be considered as an independent prognostic factor for PFS or OS.

Relaxin and prostaglandin E(2) regulate interleukin 11 during human endometrial stromal cell decidualization

Decidualization of endometrial stromal cells and IL-11 signaling are essential for embryo implantation in the mouse. We investigated the effects of relaxin (RLX) and prostaglandin E(2) (PGE(2)) on IL-11 secretion by human endometrial stromal cells (HESC) and during cAMP or medroxyprogesterone acetate (P)-induced decidualization. cAMP-decidualized HESC secreted high levels of IL-11. RLX, cAMP, or PGE(2) increased IL-11 mRNA and IL-11 secretion, with maximal response to RLX and cAMP. Addition of the cAMP/protein kinase A inhibitor Rp-adenosine-3,5-cyclic-monophosphorothioate to either RLX- or PGE(2)-treated cells decreased IL-11 secretion. Indomethacin treatment decreased IL-11 secretion, which was largely restored by cotreatment with PGE(2) or RLX. Cotreatment of HESC with RLX, PGE(2), or cAMP and estrogen plus P down-regulated IL-11 mRNA and IL-11 secretion at 24 h, before secretion of prolactin (decidualization marker). Addition of W147AIL-11 (IL-11 signaling inhibitor) reduced prolactin secretion stimulated by RLX or PGE(2) and estrogen plus P. This is the first demonstration that cAMP-decidualized HESC secrete IL-11 and that IL-11 mRNA and IL-11 secretion are regulated by RLX and PGE(2), partly via a cAMP/protein kinase A-dependent pathway. Blocking IL-11 signaling reduced RLX+P- or PGE(2)+P-induced decidualization, suggesting that RLX and PGE(2) act via IL-11. This is important in understanding implantation and regulation of fertility.

266. Supressor of cytokine signalling 3 regulates IL-11 induced human endometrial stromal cell decidualization

Decidualization of endometrial stromal cells is critical for embryo implantation and establishment of pregnancy. Locally produced cytokines such as interleukin (IL)-11 enhance decidualization of human endometrial stromal cells (HESC). IL-11 signaling is negatively regulated by suppressor of cytokine signaling (SOCS) proteins. IL-11 stimulates SOCS3 in human pituitary cells. The aim of this study was to examine the role of SOCS3 on IL-11 induced HESC decidualization. Decidualization of HESC was assessed using an in vitro model in which estrogen (E)+progesterone (P) or cAMP was administered for 8 days to cells. Medium was collected for prolactin (PRL) assay (a decidual marker). Cellular protein was extracted for Western analysis and cellular RNA for real-time RT-PCR analysis. SOCS3 was overexpressed in HESC cells and the effect on decidualization assessed. HESC treated with E+P or cAMP secreted PRL from day 6. Treatment of HESC with E+P or cAMP increased the abundance of SOCS3 protein, coinciding with an increase in PRL secretion. cAMP maximally stimulated SOCS3 protein and mRNA during decidualization. Antiprogestin (onapristone) added to E+P or cAMP treated cells at day 6 reduced PRL secretion but had no influence on SOCS3 abundance suggesting that SOCS3 protein was not regulated via the P-receptor pathway. Addition of IL-11 to HESC increased SOCS3 abundance from 1 h. SOCS3 abundance returned to control levels following treatment of cells with IL-11 and IL-11 neutralising antibody. SOCS3 overexpression in HESC treated with cAMP reduced PRL secretion compared to mock- or non-transfected HESC. Furthermore, IL-11 mediated decidualization was diminished by SOCS3 overexpression. We have demonstrated for the first time that SOCS3 regulates IL-11 induced decidualization and that SOCS3 overexpression in HESC disrupts decidualization. This knowledge is important in understanding the mechanisms by which IL-11 promotes decidualization of HESC and thus the formation of decidua, an essential component of a functional placenta.

254.Interleukin-11 enhances endometrial stromal cell decidualisation via activation and inhibition of target genes

Differentiation of endometrial stromal cells into decidual cells is essential for successful embryo implantation. Interleukin (IL)-11 signalling is required for decidualisation in the mouse (1,2) and the expression pattern of IL-11 and its receptors during the menstrual cycle suggests a role for IL-11 in human decidualisation (3). Exogenous IL-11 has been shown to enhance hormone-induced decidualisation of human endometrial stromal cells in culture (4). This study aimed to determine the effects of IL-11 on downstream gene expression in endometrial stromal cells following 12 days of progesterone-induced decidualisation, and to examine the expression and functional significance of IL-11 target genes during this process. Stromal cells isolated from endometrial biopsies (n = 6) were decidualised with 17β-oestradiol and medroxyprogesterone acetate (EP) or EP with 100 ng/mL recombinant human IL-11. Medium was changed every 48 h, and total RNA extracted on Day 12 for gene expression analysis using custom-made 15K cDNA microarrays. Quantitative real-time RT-PCR was performed on the same samples to confirm gene expression levels. In subsequent experiments (n = 2), cells were cytocentrifuged onto glass slides for immunocytochemistry using specific antibodies. Microarray analysis revealed 16 upregulated and 11 downregulated cDNAs in EP + IL-11 compared to EP treated cells. Among these were IL-1β (6.1-fold upregulated) and insulin-like growth factor binding protein (IGFBP)-5 (3.6-fold downregulated). Using real-time RT-PCR, IL-11 was confirmed to increase IL-1β (fold change 1.3–107.1) and decrease IGFBP-5 (fold change 2.8–469.0) transcript abundance in 6 patients. Immunolocalisation of IL-1β in EP and EP + IL-11 treated cells revealed more intense vesicular cytoplasmic staining with IL-11 treatment, while staining intensity for IGFBP-5 was not affected. Interactions between IL-11 and its downstream targets IL-1β and IGFBP-5 are likely to have functional importance in early pregnancy, and may provide novel targets for the manipulation of human fertility. (1) Robb L, Li R, Hartley L, Nandurkar HH, Koentgen F, Begley CG (1998) Nat. Med. 4, 303–308. (2) Bilinski P, Roopenian D, Gossler A (1998) Gene Dev. 12, 2234–2243. (3) Dimitriadis E, Salamonsen LA, Robb L (2000) Mol. Hum. Reprod. 6, 907–914. (4) Dimitriadis E, Robb L, Salamonsen LA (2002) Mol. Hum. Reprod. 8, 636–643.

270.Macrophage inhibitory cytokine-1 at the maternal - fetal interface in early pregnancy

Macrophage inhibitory cytokine-1 (MIC-1) is a transforming growth factor-β (TGF-β) superfamily member, first isolated from activated macrophages and subsequently localised in the human placenta. We previously reported that decreased circulating levels in very early pregnancy are associated with subsequent miscarriage. We undertook these current in vitro studies to investigate possible roles for MIC-1 in early pregnancy: (1) regulation of placental matrix metalloproteinase-2 and -9 (MMP-2 and -9); (2) effect on placental apoptosis; and (3) regulation of endometrial stromal cell decidualisation. (1) First trimester placental explant cultures were treated with 100–200 ng/mL MIC-1 � 1/1000 (v/v) anti-MIC-1 antibody. MMP-2 and -9 were measured by gelatin zymography. MMP activation via the plasminogen activation pathway was examined by measuring mRNA expression for urokinase plasminogen activator and its receptor (uPA, uPAR) and type-1 plasminogen activation inhibitor (PAI-1). (2) In first trimester trophoblast explants, apoptosis was induced in vitro with tumor necrosis factor-α (TNF-α) and interferon-β (IFN-β) � 200 ng/mL MIC-1. The pro-apoptosis factor caspase-3 was localised by immunohistochemistry. (3) Using an established model of oestrogen and progesterone induced endometrial stromal cell decidualisation, MIC-1 production was measured and correlated with morphological changes. Cultures were also treated with 20 ng/mL MIC-1. MIC-1 treatment inhibited activation of both MMP-2 and MMP-9 while treatment with anti-MIC-1 antibody blocked the inhibition. uPA, uPAR and PAI-1 mRNA did not change with either treatment. MIC-1 treatment mitigated TNF-α/IFN-β induced trophoblast apoptosis. MIC-1 production increased during induced decidualisation and MIC-1 treatment facilitates further decidualisation in this model. MIC-1 appears to have a number of potentially important functions in the human placenta and decidua consistent with physiological roles in normal placentation. Whether these functions are key to successful pregnancy remains to be studied.

227.An inhibitor of leukemia inhibitory factor signalling blocks embryo implantation in the mouse

Embryo implantation is a critical step in the establishment of pregnancy. Endometrial leukemia inhibitory factor (LIF) is essential for embryo implantation in the mouse (1). Uterine LIF is expressed in the luminal epithelium on Day 3 of pregnancy (D3) (D0�=�day of plug detection) and signals via activation of signal transducer and activator of transcription (Stat) 3 (2). We examined the effect of a novel LIF signalling inhibitor on the phosphorylation (p) of Stat3 during early pregnancy and on embryo implantation in the mouse. We injected LIF inhibitor into one uterine horn and PBS into the other uterine horn of the mouse at D3 and examined the effect on pStat3 immunostaining in the luminal epithelium between 30 and 360�min later. We found no immunoreactive pStat3 in luminal epithelium following treatment with LIF inhibitor at 60 and 90�min but variable staining at other time points. The PBS-treated uterine horn showed intense immunostaining at all times. LIF inhibitor (1mg/kg body weight per day) or PBS was administered to mice (a) subcutaneously, (b) intraperitoneally, at 8-hourly intervals for 3�days from D2, or (c) continuously into the peritoneal cavity via Alzet pumps from D2. No effect was seen on implantation at D6. When LIF antagonist (3.5mg/kg/day) or PBS were administered by Alzet pumps from D2 together with ip injections, 4-hourly from D3 for 36�h, there were no implantation sites in the uteri of treated mice (n�=�5) while the control mice (n�=�4) had 3.6���0.5�sites (P�<�0.001). Histologically, the uteri of the treated mice resembled non-pregnant uterus, while the control uterus resembled post-implantation uterus. The results demonstrate that treatment of mice during early pregnancy with a novel LIF inhibitor blocks LIF action in vivo and embryo implantation. This knowledge is important for development of novel contraceptives. (1) Stewart, C. L., Kaspar, P., Brunet, L. J., Bhatt, H., Gadi, I., Kontgen, F., Abbondanzo, S. J. (1992) Nature 359, 76–79. (2) Cheng, J. G., Chen, J. R., Hernandez, L., Alvord, W. G., Stewart, C. L. (2001) Proc. Natl Acad. Sci. USA 98, 8680–8685.

IL-11 and IL-11Ralpha immunolocalisation at primate implantation sites supports a role for IL-11 in placentation and fetal development

Embryo implantation, endometrial stromal cell decidualization and formation of a functional placenta are critical processes in the establishment and maintenance of pregnancy. Interleukin (IL)-11 signalling is essential for adequate decidualization in the mouse uterus and IL-11 promotes decidualization in the human. IL-11 action is mediated via binding to the specific IL-11 receptor alpha (IL-11Ralpha). The present study examined immunoreactive IL-11 and IL-11Ralpha in cycling rhesus monkey endometrium, at implantation sites in cynomolgus and rhesus monkeys and in human first trimester decidua and defined distinct spatial and temporal patterns. In cycling rhesus monkey endometrium, IL-11 and IL-11Ralpha increased in both basalis and functionalis regions during the secretory compared with the proliferative phase, with changing cellular locations in luminal and glandular epithelium and stroma. The patterns were similar overall to those previously described in human endometrium. Differences were seen in immunostaining during implantation in cynomologus and rhesus monkey. In the cynomolgus, very little staining for IL-11 or IL-11Ralpha was seen in syncytio- and cyto-trophoblast cells in the villi between days 12 and 150 of pregnancy although there was moderate staining in cytotrophoblast in the shell between days 12 and 17 and in subpopulations of cytotrophoblast cells invading the arteries at day 17. By contrast in the rhesus monkey between days 24 and 35 of pregnancy and in human first trimester placenta, cyto- and syncytio-trophoblast in the villi but not cytotrophoblast in the shell were positively stained. The most intense staining for both IL-11 and IL-11Ralpha was present within the decidua in the maternal component of implantation sites in all three primates but moderate staining was also present in maternal vascular smooth muscle and glands perivascular cells and epithelial plaques. These results are consistent with a role for IL-11 both during decidualization and placentation in primates.

Complex regulation of decidualization: a role for cytokines and proteases--a review

Decidualization of the endometrial stroma is a precondition for successful establishment of pregnancy. While the local molecular mechanisms driving decidualization are still largely unknown, a number of autocrine/paracrine factors have been identified as differentiation factors in this process. These include the cytokines, interleukin 11, activin A and monoclonal non-specific suppressor factor beta (MNSFbeta). Furthermore, locally produced proteases, including proprotein convertase 6 and matrix metalloproteinases, enable expansion of the tissue and processing of regulatory molecules. This article reviews recent work from our laboratory on the roles of these factors in decidualization.

Interleukin 11 advances progesterone-induced decidualization of human endometrial stromal cells

Differentiation of endometrial stromal cells into decidual cells is crucial for embryo implantation and placentation. Interleukin (IL)-11 signalling is essential for adequate decidualization in the mouse uterus. We examined the role of IL-11 during progesterone-induced decidualization of human endometrial stromal cells over a 10-12 day period, using prolactin (PRL) production as a decidual marker. These cells produced biologically active IL-11 and expressed IL-11, IL-11Ralpha and PRL mRNA during decidualization. Neutralization of endogenous IL-11 with an anti-human (hu)IL-11 antibody (AB) reduced production of PRL from day 8 and insulin-like growth factor binding protein (IGFBP)-1, another marker of decidualization, from day 10 of culture. Following AB washout, PRL and IGFBP-1 secretion increased. Addition of recombinant (r)huIL-11 (10 or 100 ng/ml) to endometrial stromal cells increased secretion of PRL from day 4 and IGFBP-1 from day 6 compared with progesterone alone. Morphological signs of differentiation accompanied biochemical differentiation in the progesterone-treated cells and were further induced by exogenous rhuIL-11. Our observations demonstrate that human endometrial stromal cells produce biologically active IL-11, which promotes progesterone-induced decidualization. These results suggest that IL-11 has both paracrine and autocrine actions on human endometrial stromal cells and plays an important role in preparing the human endometrium for implantation.

Genes involved in implantation

The endometrium is normally a hostile environment for an embryo, except for a short phase in each reproductive cycle known as the 'window of receptivity'. The precise molecular events involved in this transformation are not well understood. Application of state-of-the-art techniques of the 1990s has identified some of the genes involved, which are reviewed here. Mice with a null mutation in either the gene for leukemia inhibitory factor or the interleukin-11 receptor alpha chain are infertile, owing in both cases to a failure of embryo implantation. Both of these genes are expressed in the human endometrium with patterns suggesting a role in human fertility. The technique of RNA differential display has been applied to a comparison of the expression of genes at implantation sites v. inter-implantation sites in the mouse uterus on the first day of implantation, and has defined additional genes whose products may be important for this process. Among these are the calcium-binding protein D9K, the monoclonal non-specific suppressor factor beta, and the splicing factor SC35. The major challenge is to determine whether manipulation of such genes can increase or decrease endometrial receptivity in humans.