Human trophoblast function during the implantation process

mTOR mediates human trophoblast invasion through regulation of matrix-remodeling enzymes and is associated with serine phosphorylation of STAT3

The intracellular signaling molecule mammalian target of rapamycin (mTOR) is essential for cell growth and proliferation. It is involved in mouse embryogenesis, murine trophoblast outgrowth and linked to tumor cell invasiveness. In order to assess the role of mTOR in human trophoblast invasion we analyzed the in vitro invasiveness of HTR-8/SVneo immortalized first-trimester trophoblast cells in conjunction with enzyme secretion upon mTOR inhibition and knockdown of mTOR protein expression. Additionally, we also tested the capability of mTOR to trigger signal transducer and activator of transcription (STAT)-3 by its phosphorylation status. Rapamycin inhibited mTOR kinase activity as demonstrated with a lower phosphorylation level of the mTOR substrate p70 S6 kinase (S6K). With the use of rapamycin and siRNA-mediated mTOR knockdown we could show that cell proliferation, invasion and secretion of matrix-metalloproteinases (MMP)-2 and -9, urokinase-like plasminogen activator (uPA) and its major physiological uPA inhibitor (PAI)-1 were inhibited. While tyrosine phosphorylation of STAT3 was unaffected by mTOR inhibition and knockdown, serine phosphorylation was diminished. We conclude that mTOR signaling is one major mechanism in a tightly regulated network of intracellular signal pathways including the JAK/STAT system to regulate invasion in human trophoblast cells by secretion of enzymes that remodel the extra-cellular matrix (ECM) such as MMP-2, -9, uPA and PAI-1. Dysregulation of mTOR may contribute to pregnancy-related pathologies caused through impaired trophoblast invasion.

New discoveries on the biology and detection of human chorionic gonadotropin

Human chorionic gonadotropin (hCG) is a glycoprotein hormone comprising 2 subunits, alpha and beta joined non covalently. While similar in structure to luteinizing hormone (LH), hCG exists in multiple hormonal and non-endocrine agents, rather than as a single molecule like LH and the other glycoprotein hormones. These are regular hCG, hyperglycosylated hCG and the free beta-subunit of hyperglycosylated hCG. For 88 years regular hCG has been known as a promoter of corpus luteal progesterone production, even though this function only explains 3 weeks of a full gestations production of regular hCG. Research in recent years has explained the full gestational production by demonstration of critical functions in trophoblast differentiation and in fetal nutrition through myometrial spiral artery angiogenesis. While regular hCG is made by fused villous syncytiotrophoblast cells, extravillous invasive cytotrophoblast cells make the variant hyperglycosylated hCG. This variant is an autocrine factor, acting on extravillous invasive cytotrophoblast cells to initiate and control invasion as occurs at implantation of pregnancy and the establishment of hemochorial placentation, and malignancy as occurs in invasive hydatidiform mole and choriocarcinoma. Hyperglycosylated hCG inhibits apoptosis in extravillous invasive cytotrophoblast cells promoting cell invasion, growth and malignancy. Other non-trophoblastic malignancies retro-differentiate and produce a hyperglycosylated free beta-subunit of hCG (hCG free beta). This has been shown to be an autocrine factor antagonizing apoptosis furthering cancer cell growth and malignancy. New applications have been demonstrated for total hCG measurements and detection of the 3 hCG variants in pregnancy detection, monitoring pregnancy outcome, determining risk for Down syndrome fetus, predicting preeclampsia, detecting pituitary hCG, detecting and managing gestational trophoblastic diseases, diagnosing quiescent gestational trophoblastic disease, diagnosing placental site trophoblastic tumor, managing testicular germ cell malignancies, and monitoring other human malignancies. There are very few molecules with such wide and varying functions as regular hCG and its variants, and very few tests with such a wide spectrum of clinical applications as total hCG.

Interleukin 11 inhibits human trophoblast invasion 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 11 (IL11) is maximally expressed in the decidua, with its receptor, IL11 receptor alpha (IL11RA), also identified on invasive EVTs in vivo. Although a role for IL11 in EVT migration has been established, whether it also plays a role in regulating EVT invasion is unknown. We investigated whether IL11 influences human EVT invasion and the signaling pathways and underlying mechanisms that may be involved, using the HTR-8/SVneo immortalized EVT cell line and primary EVTs as models for EVTs. Interleukin 11 (100 ng/ml) significantly inhibited invasion of EVT cells by 40% to 60% (P < 0.001). This effect was abolished by inhibitors of signal transducer and activator of transcription 3 (STAT3) but not of mitogen-activated protein kinase (MAPK) pathways. Interleukin 11 (100 ng/ml) had no effect on matrix metallopeptidases 2 and 9 (MMP2 and MMP9), tissue inhibitors of MMP (TIMP1, TIMP2, and TIMP3), plasminogen activator urokinase (PLAU), plasminogen activator urokinase receptor (PLAUR), and serpin peptidase inhibitors 1 and 2 (SERPINE1 and SERPINE2) in EVT-conditioned media and/or cell lysates. Interleukin 11 (100 ng/ml) also did not regulate EVT cell adhesion or integrin expression. These data demonstrate that IL11 inhibits human EVT invasion via STAT3, indicating a likely role for IL11 in the decidual restraint of EVT invasion during normal pregnancy.

Opposite effects of transforming growth factor-beta activation and rho-associated kinase inhibition on human trophoblast migration in a reconstituted placental-endometrial coculture system

Placental implantation involves highly regulated trophoblast invasion of the endometrial stroma. TGFbeta is a known regulator of this process. This study examines the effect of TGFbeta on extravillous cytotrophoblastic cell (EVCT) migration in cocultures of first-trimester human chorionic villus explants and primary human endometrial fibroblasts. Migration of EVCTs was followed by phase-contrast time-lapse microscopy and was shown to highly depend on the endometrial fibroblast matrix. Interstitial EVCT invasion was also analyzed by confocal microscopy of fluorescently prelabeled trophoblasts and endometrial fibroblasts. As expected, addition of TGFbeta led to inhibition of EVCT invasion of the endometrial cell layer. This inhibition was characterized by formation of compact EVCT stacks at migration fronts and displacement of endometrial fibroblasts. We tested the role of the RhoA/Rho-associated kinase (ROCK) pathway, a TGFbeta-dependent pathway known to regulate cell migration. Interestingly, blocking ROCK with the chemical inhibitor Y27632 had an effect opposite to TGFbeta activation because it promoted superficial EVCT migration on the endometrial cell layer. These data suggest a role for ROCK in the TGFbeta-dependent control of trophoblast migration. Furthermore, they indicate that even though ROCK signaling plays a role in human trophoblast cell invasion, EVCT migration can still occur in the absence of ROCK activity.

Cellular and molecular physiopathology of congenital toxoplasmosis: the dual role of IFN-gamma

Toxoplasma gondii is one of the few pathogens that can cross the placenta. Frequency and severity of transmission vary with gestational age. While the control of acquired toxoplasmosis is already well explored, the control of materno-foetal transmission of the parasite remains almost unknown. This is partly due to the lack of an animal model to study this process. This review summarises the studies which have been undertaken and shows that the mouse is a valuable model despite obvious differences to the human case. The paramount role of the cellular immune response has been shown by several experiments. However, IFN-gamma has a dual role in this process. While its beneficial effects in the control of toxoplasmosis are well known, it also seems to have transmission-enhancing effects and can also directly harm the developing foetus. The ultimate goal of these studies is to develop a vaccine which protects both mother and foetus. Therefore, it is useful to study the mechanisms of natural resistance against transmission during a secondary infection. In this setting, the process is more complicated, involving both cellular and also humoral components of the immune system. In summary, even if the whole process is far from being elucidated, important insights have been gained so far which will help us to undertake rational vaccine research.

Use of reticulin stain in the diagnosis of intra-uterine gestation

AIMS

The diagnosis of intra-uterine gestation may be problematic when specimens from clinically suspected products of conception lack chorionic villi and/or fetal somatic tissues, since the distinction of intermediate trophoblast from decidual or myometrial elements can be difficult. The placental site is also characterised by stromal changes, including the deposition of a characteristic extracellular fibrinoid matrix. We have noted that these stromal changes may be highlighted by a simple reticulin stain; therefore, we have evaluated reticulin staining in a series of endometrial biopsy specimens from patients with intra-uterine and ectopic gestations.

METHODS

Reticulin staining was performed in 28 endometrial specimens from patients with first trimester intra-uterine gestations, including 14 cases that lacked chorionic elements. Eight endometrial samples from patients with concurrent histologically verified tubal ectopic pregnancy were also examined. Selected cases were also studied using a Masson trichrome stain, and immunohistochemically with antisera to cytokeratin and HPL.

RESULTS

There was a distinct increase in reticulin staining, usually evident at low power magnification, in most areas of decidua showing implantation site. Prominent reticulin staining was present around the decidual and trophoblast cells and there was also accentuation around stromal vessels, glands and myometrial cells. There was no clear difference in staining within areas of decidua including only rare intermediate trophoblast cells but this pattern was seldom seen in isolation. Minimal changes were seen in the placental site using the Masson trichrome stain.

CONCLUSION

Reticulin stains may prove useful in the assessment of endometrial specimens from patients with purported intra-uterine gestations when chorionic elements are not identified. Since the staining technique is simple and can be quickly performed, it could be used as an adjunct to conventional H&E assessment and to select appropriate specimen blocks for additional more sensitive studies, including immunohistochemistry.

Cyclosporin A improves murine pregnancy outcome in abortion-prone matings: involvement of CD80/86 and CD28/CTLA-4

Immune regulation during pregnancy is complex, and thus an optimal therapy for pregnancy complications is always a big challenge to reproductive medicine. Cyclosporin A (CsA), a potent immunosuppressant, prevents rejection of allografts by hosts, but little is known about the modulating effect of CsA on the materno-fetal relationship. Here, pregnant CBA/J females mated with DBA/2 males as an abortion-prone model were administered with CsA on day 4.5 of gestation, and the pregnant CBA/J females mated with BALB/c males were established as successful pregnancy control. It was demonstrated that administration of CsA at the window of implantation significantly up-regulated the expression of CTLA-4, while down-regulating the levels of CD80, CD86, and CD28 at the materno-fetal interface in the CBA/J×DBA/2 abortion-prone matings, and the embryo resorption rate of the abortion-prone matings reduced significantly after CsA treatment, implying that modulation of costimulatory molecule expression by CsA might contribute to preventing the fetus from maternal immune attack. In addition, treatment with CsA induced enhanced growth and reduced cell apoptosis of the murine trophoblast cells. Together, these findings indicate that CsA has a beneficial effect on the materno-fetal interface in abortion-prone matings, leading to a pregnancy outcome improvement, which might provide new therapeutics for spontaneous pregnancy wastage.

Genetic and epigenetic factors contribute to the onset of preeclampsia

Preeclampsia (PE) is a major cause of perinatal materno-foetal morbidity and pregnancy-associated-mortality in industrialized countries. Clinically, PE associates maternal pregnancy-induced hypertension with proteinuria. PE is often considered as a two-stage disease. The first stage is a shallow cytotrophoblastic invasion which induces cycles of hypoxia-reoxygenation at the placental level. Subsequently an abnormal expression pattern occurs and is followed by the release of soluble factors and trophoblastic debris in the maternal blood flow. These stimuli trigger the second phase of the disease, the maternal syndrome. Although some molecular actors have been recently identified, mechanisms of the disease onset remains poorly understood. It seems that combinations of genetic, epigenetic and environmental factors are involved. Here, we suggest that epigenetic marks have to be considered to decipher the physiopathological process of PE. Since these marks must be established early and are traceable in the maternal blood flow, they could constitute a diagnosis tool.

Myocardial Matrix Remodeling and the Matrix Metalloproteinases: Influence on Cardiac Form and Function

It is now becoming apparent that dynamic changes occur within the interstitium that directly contribute to adverse myocardial remodeling following myocardial infarction (MI), with hypertensive heart disease and with intrinsic myocardial disease such as cardiomyopathy. Furthermore, a family of matrix proteases, the matrix metalloproteinases (MMPs) and the tissue inhibitors of MMPs (TIMPs), has been recognized to play an important role in matrix remodeling in these cardiac disease states. The purpose of this review is fivefold: 1) to examine and redefine the myocardial matrix as a critical and dynamic entity with respect to the remodeling process encountered with MI, hypertension, or cardiomyopathic disease; 2) present the remarkable progress that has been made with respect to MMP/TIMP biology and how it relates to myocardial matrix remodeling; 3) to evaluate critical translational/clinical studies that have provided a cause-effect relationship between alterations in MMP/TIMP regulation and myocardial matrix remodeling; 4) to provide a critical review and analysis of current diagnostic, prognostic, and pharmacological approaches that utilized our basic understanding of MMP/TIMPs in the context of cardiac disease; and 5) most importantly, to dispel the historical belief that the myocardial matrix is a passive structure and supplant this belief that the regulation of matrix protease pathways such as the MMPs and TIMPs will likely yield a new avenue of diagnostic and therapeutic strategies for myocardial remodeling and the progression to heart failure.

Role of placentally produced inflammatory and regulatory cytokines in pregnancy and the etiology of preeclampsia

Human pregnancy is a metabolic and immune challenge for the mother who has to accommodate in her womb a semi-allogeneic fetus whose energy needs increase tremendously with gestation. Recent compelling research has suggested that proper inflammatory changes and oxidative balance are a requisite for successful pregnancy. The placenta is an integral component of this inflammatory response as it actively produces a variety of cytokines and immunomodulatory hormones. In preeclampsia, a life-threatening disorder of pregnancy that is characterized by widespread damage and dysfunction of the maternal endothelium, placental oxidative stress and aberrant cytokine expression induces an exaggerated maternal systemic inflammatory response to pregnancy.

Impact of piroxicam beta-cyclodextrin on the efficacy of the intrauterine device in a rat model

OBJECTIVE

To elucidate the effect of piroxicam beta-cyclodextrin (PbetaCD), a non-steroidal anti-inflammatory drug (NSAID), on the efficacy of the intrauterine device (IUD) in a rat model.

METHODS

Forty nulliparous female Wistar rats were allocated to one of four groups, comprising each 10 of these animals. Group I: neither IUD nor medication; group II: IUD, but no medication; group III: IUD and PbetaCD; and group IV: PbetaCD only. In groups II and III, a string of 3/0 silk suture of 2 cm long was transcervically placed in one of the horns of the bicornuate uterus of the rat. Rats in group III were treated during the 18 days following IUD placement with 3 mg/kg/day PbetaCD administered via a feeding tube; group IV received PbetaCD for the same length of time, but had no IUD inserted. The rats were then mated. Thereafter, vaginal smears were taken and assessed daily, in the early morning, for the presence of spermatozoa. The day when spermatozoa were detected was considered to be the first day of gestation. On gestational day 19, both uterine horns of all rats were evaluated for the presence and number of embryos.

RESULTS

In group II, mean embryo counts in the horn with or without IUD were 1.0 +/- 0.2 and 4.5 +/- 0.3, respectively (p < 0.01). The comparison of group II with group I showed that the presence of an IUD in one horn did not affect the mean embryo counts in the contralateral horn (4.5 +/- 0.3 versus 5.1 +/- 0.9, p > 0.05). In groups II and III, mean numbers of embryos in the horn with IUD were 1.0 +/- 0.2 and 2.7 +/- 0.4, respectively (p < 0.01). No difference in the mean embryo counts was observed between group I (5.1 +/- 0.9) and IV (4.8 +/- 0.9; p > 0.05).

CONCLUSIONS

The IUD had a contraceptive effect in the rat model. The IUD in one horn did not affect the number of embryos in the contralateral horn. In this model, IUDs appear to exert a local effect, i.e. counteracted by PbetaCD. This drug had no adverse effect on the fertility of rats without IUD in situ.