PP124. Trofoblastic invasion: The role of subunits STAT1 and STAT3

INTRODUCTION

The trophoblastic migration/invasion are controlled by cytokines and growth factors that use intracellular pathways of signal to promote the regulation of gene expression, proliferation, cells differentiation, angiogenesis and embryonic development. The most important mediator of cytokine in trophoblastic invasion is the Janus-Kinase/signal transducer and activator of transcription (JAK/STAT). STATs are amino acids, compounds of 700-850 variable long-chain with isoforms α and β and molecular weight between 83-113kDa. The role of these factors in the pregnancy set up may contribute to adopt interventions that could contribute to prophylaxis and/or treatment of abnormalities in the course of gestation when installed early.

OBJECTIVES

Search on database the role of STAT in the process of trophoblastic invasion with emphasis on subunits STAT1 and STAT3.

METHODS

This is a review performed on PubMed database. Have been included Studies found from 1992 (the year of discovery of STATs) until July 2011, without language restriction. The descriptors were: "Signal transducers and activators of transcription "and" Trophoblast". In the end we excluded bibliographical review.

RESULTS

Five of the six selected papers studied the role of STAT3 in the physiology of the trophoblastc invasion process. One of them, indirectly by selection process of lactobacilli of vaginal flora endogenous, during change of vaginal pH on pregnancy, altering the release of greater or lesser number of Interleukin-10 which modulates the activation JAK/STAT. Among them, one of the study refers to involvement of STAT1 in the immunomodulation of interface fetus-mother.

CONCLUSION

STAT3 is directly involved in the process of trophoblast invasion either in its endometrium adherence to, angiogenesis, invasion and regulation of invasion. And STAT1 is involved in immunomodulation through its suppression by trophoblast STAT utron. Several soluble factors that are generally present in the decidua, especially hepatocyte growth factor, granulocyte macrophagocytic-colony stimulating factors, interleukin-6, interleukin-11 and inhibition leukemia factor , which have been described by using the JAK-STAT activating STAT1 and STAT3 for intracellular signaling and from this process may influence the invasion trophoblast.

PP055. Preliminary results of the more prepared study (microparticle orientated risk evaluation in the prediction of preeclampsia among risk gravidas): A multicenter prospective prognostic marker study

INTRODUCTION

Preeclampsia (PE) is a potentially dangerous pregnancy pathology contributing to a higher worldwide mortality and morbidity. The negative influence of syncytiotrophoblastic microparticles (STBMs) on the placenta and maternal endothelia is thought to play a key role in generating the inflammatory effects that lead to PE symptoms. Doppler sonography of the uterine arteries assists in identifying a risk population, however, the positive predictive value for this method is low.

OBJECTIVES

Aim of this study is to evaluate whether STBMs can serve as an accessory marker to conventional Doppler sonography to better identify pregnant women who will actually develop PE.

METHODS

Pregnant women between 19-21 gestational weeks (GW) with abnormal uterine perfusion were enrolled into this prospective study. Plasma samples were taken at inclusion (baseline) and at two further visits at 8 week intervals to follow STBM concentration alterations during pregnancy. The primary endpoint assessed is PE and/or hemolysis, elevated liver, low platelets (HELLP) syndrome. Other PE-associated pathologies (intrauterine growth retardation [IUGR], intrauterine fetal demise [IUFD], placental abruption, premature delivery) constitute the secondary endpoints. Maternal STBM concentrations were measured using a home made Enzyme Linked Sorbent Assay (ELSA) which specifically measures STBMs. The receiver operating characteristics (ROC) for baseline measures are graphically displayed and area under curve (AUC) is estimated including 95% confidence levels.

RESULTS

Of the 73 women included in the study, 16 developed PE (cases) and 56 did not (control). After analyses of mid-gestational probes, the ROC curve was in close proximity to the line of no-discrimination.

CONCLUSION

Our preliminary results indicate that the maternal STBM concentration at mid-gestation does not predict the development of PE or associated pregnancy pathologies. Further analysis is underway to assess whether STBM measurements at later gestational time points can predict PE shortly before onset of disease.

Inhibiton of RET and JAK2 signals and upregulation of VEGFR3 phosphorylation in vitro by galectin-1 in trophoblast tumor cells BeWo

BACKGROUND

Galectin-1 (gal-1), a member of the mammalian beta-galactoside-binding proteins, binds to cell surface glycoproteins (Mucin-1) on trophoblast cells. Although it has been demonstrated that gal-1 induces cell differentiation processes in these cells, no information on its signal transduction processes is available so far. As tyrosine phosphorylation is a major mechanism that controls multiple biological processes including cell differentiation, survival and proliferation, the aim of this study was to examine which human receptor tyrosine kinases (RTKs) were phosphorylated in trophoblast cells by gal-1.

MATERIALS AND METHODS

BeWo choriocarcinoma cells were incubated for 24h in the absence (controls) and presence of 60microg/ml galectin-1. With the RayBio Human RTK Phosphorylation Antibody Array 1, the relative levels of phosphorylation of different human RTKs could be detected simultaneously. The signal intensities were compared and quantified with the Quantity One Version 4.5.2 program. Gal-1-treated and non-treated cells were incubated with antibodies against REarranged during Transfection (RET) and phosphorylated RET(Y905). Staining reaction was performed with the avidin-biotinylated peroxidase complex (ABC) reagent.

RESULTS

We demonstrated that gal-1 inhibited RET and Janus Kinase 2 (JAK2) signals and upregulated Vascular endothelial growth factor receptor 3 (VEGFR3) signal in BeWo cells. We also showed the downregulation of phosphorylation on RET phosphotyrosine residue 905 in BeWo cells with phosphorylation specific antibodies and immunocytochemistry.

CONCLUSION

Out of a number of 71 different RTKs, the stimulation of BeWo cells with gal-1 showed a significant alteration of signal intensity in only 3 RTKs: JAK2, RET and VEGFR3. Our data suggest that phosphorylation of these RTKs could be involved in cell differentiation processes that could be responsible for the already known effect of gal-1 on BeWo cells, the inhibition of proliferation.