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.

The Impact of Oxidative Stress of Environmental Origin on the Onset of Placental Diseases

Oxidative stress (OS) plays a pivotal role in placental development; however, abnormal loads in oxidative stress molecules may overwhelm the placental defense mechanisms and cause pathological situations. The environment in which the mother evolves triggers an exposure of the placental tissue to chemical, physical, and biological agents of OS, with potential pathological consequences. Here we shortly review the physiological and developmental functions of OS in the placenta, and present a series of environmental pollutants inducing placental oxidative stress, for which some insights regarding the underlying mechanisms have been proposed, leading to a recapitulation of the noxious effects of OS of environmental origin upon the human placenta.

Reference ranges of AMH in early pregnancy: the Generation R Study, a population-based prospective cohort study

Objective: The objective of this study is to establish maternal reference values of AMH in a fertile multi-ethnic urban pregnant population and to evaluate the effect of gestational age. Design: The Generation R Study is an ongoing population-based prospective cohort study from early pregnancy onwards. Setting: Rotterdam, the Netherlands, out of hospital setting. Population: In 5806 women serum AMH levels were determined in early pregnancy (median 13.5 weeks; 95% range 10.5-17.2). Methods: The model-based AMH reference ranges for maternal age and gestational age were created using GAMLSS. Associations between AMH and several first trimester biomarkers were analyzed using multivariate linear regression analyses. Main outcome measures: AMH levels in early pregnancy and the association with placental biomarkers, hCG, sFLT, and PLGF. Results: A nomogram of AMH in early pregnancy was developed. Serum AMH levels showed a decline with advancing gestational age. Higher AMH levels were associated with a higher level of hCG and sFLT. This last association was predominantly mediated by hCG. AMH levels were negatively associated with PLGF levels. Conclusion: In this large study we show that AMH levels in the first trimester decrease with advancing gestational age. The association between AMH and the placental biomarkers hCG, sFLT and PLGF suggests a better placental development with a lower vascular resistance in mothers with higher AMH levels. AMH might be useful in predicting adverse pregnancy outcome due to impaired placental development. Keywords: Ovarian reserve, placental biomarker, nomogram, first trimester, human Choriogonadotrophin (hCG), soluble FMS-Like Tyrosine kinase-1 (sFLT), Placental Growth Factor (PLGF).

Pregnancy depends on a delicate balance of immune activation and regulation

It is well recognized that immune tolerance is important to prevent semiallografted fetuses from rejection by maternal immunocompetent cells; however, immune activation also plays an important role in placental development and fetal growth. Basic and clinical studies have shown that an imbalance between immune activation and regulation can lead to implantation failure, miscarriage, and preeclampsia. Here, the balance between immunostimulation and immunoregulation in reproduction will be reviewed.

Gestational age and infection are greater predictors of placental histopathology than maternal prepregnancy BMI.

The placenta undergoes morphological and functional adaptions to adverse exposures during pregnancy. The effects of suboptimal maternal body mass index (BMI), preterm birth, and infection on placental histopathological phenotypes remain unclear, despite the association between these conditions and poor offspring outcomes. We hypothesized that suboptimal maternal prepregnancy BMI and preterm birth (with and without infection) would associate with altered placental maturity and morphometry, and that altered placental maturity would associate with poor birth outcomes. Clinical data and human placentae were collected from 96 pregnancies where mothers were underweight, normal weight, overweight, or obese, without other major complications. Placental histopathological characteristics were scored with an anatomical pathologist. Associations between maternal BMI, placental pathology (immaturity and hypermaturity), placental morphometry, and infant outcomes were investigated at term and preterm, with and without infection. Fetal vascular endothelium volumetric proportion was decreased, whereas syncytial knot volumetric proportion was increased, in placentae from preterm pregnancies with chorioamnionitis compared to term placentae. At term and preterm, pregnancies with overweight and obesity had a high percentage increase in proportion of immature placentae compared to normal weight. Placental maturity did not associate with infant birth outcomes. We observed placental hypermaturity and altered placental morphometry among preterm pregnancies with chorioamnionitis, suggestive of altered placental development, which may inform about pregnancies susceptible to preterm birth and infection. Our data increase our understanding of how common metabolic exposures and preterm birth, in the absence of other comorbidities or perinatal events, potentially contribute to poor pregnancy outcomes and the programming of offspring development.

Investigation of HoxB3 and Growth Factors Expression in Placentas of Various Gestational Ages

An evaluation of transforming growth factor beta (TGFβ), hepatocyte growth factor (HGF), basic fibroblast growth factor (FGF-2), fibroblast growth factors receptor 1 (FGFR1) and Hox-positive cells in the human placenta, and their correlation with gestational time at delivery and pregnancy outcomes, may provide not only a better understanding of the role of Hox genes and growth factors in human development, but also may be of clinical importance in reproductive medicine. This study analyzed the immunohistochemical identification of TGFβ, HGF, FGF-2, FGFR1 and HoxB3 in placentas of various gestational ages. We found few (+) TGFβ, moderate (++) FGF-2 and numerous (+++) HGF and FGFR1 positive structures. Occasional (0/+) to numerous (+++) HoxB3-positive structures were detected in different types of placental cells specifically, cytotrophoblasts, syncytiotrophoblast, extravillous trophoblasts, and Höfbauer cells. Correlating the appearance of HoxB3 staining in placentas with neonatal parameters, we found a statistically significant negative correlation with ponderal index (r = −0.323, p = 0.018) and positive correlation with neonate body length (r = 0.541, p = 0.046). The number of HoxB3-positive cells did not correlate with growth factors and gestational age, but with neonatal anthropometrical parameters, indicating the role of HoxB3 not only in placental development, but also in the longitudinal growth of the fetus. TGFβ and FGF-2 did not play a significant role in the development of the placenta beyond 22nd week of pregnancy, while HGF and FGFR1 immunoreactive cells increased with advancing gestation, indicating increasingly evolving maturation (growth, proliferation) of the placenta, especially in the third trimester.

Galectins in Early Pregnancy and Pregnancy-Associated Pathologies

Galectins are a family of conserved soluble proteins defined by an affinity for β-galactoside structures present on various glycoconjugates. Over the past few decades, galectins have been recognized as important factors for successful implantation and maintenance of pregnancy. An increasing number of studies have demonstrated their involvement in trophoblast cell function and placental development. In addition, several lines of evidence suggest their important roles in feto-maternal immune tolerance regulation and angiogenesis. Changed or dysregulated galectin expression is also described in pregnancy-related disorders. Although the data regarding galectins’ clinical relevance are still at an early stage, evidence suggests that some galectin family members are promising candidates for better understanding pregnancy-related pathologies, as well as predicting biomarkers. In this review, we aim to summarize current knowledge of galectins in early pregnancy as well as in pregnancy-related pathologies.

Mitochondria-mediated Maternal-fetal Interactions and Consequences of Mitochondrial Dysregulation Indicate New Roles for Mitochondria in Hypertensive Pregnancies

Oxidative stress, placental mitochondrial morphological alterations, and impaired bioenergetics are associated with hypertensive disorders of pregnancy. Here we examined mitochondrial DNA mutational load in pregnant women with pregnancy-induced hypertension and reanalyzed publicly available high-throughput transcriptomic datasets from maternal and fetal tissues from normotensive and hypertensive pregnancies. Mitochondrial dysregulation was indicated by aberrant mitochondrial gene expression, and putative consequences were examined. Women with hypertensive pregnancy had elevated mitochondrial DNA mutational load. Maternal mitochondrial dysregulation in hypertensive pregnancies was associated with pathways involved in inflammation, cell death/survival, and placental development. In fetal tissues from hypertensive pregnancies, mitochondrial dysregulation was associated with increased extracellular vesicle production. Our study demonstrates mitochondria-mediated maternal-fetal interactions during healthy pregnancy and maternal mitochondrial dysregulation in hypertensive pregnancy development.

Epigenetic Dysregulation of Trophoblastic Gene Expression in Gestational Trophoblastic Disease

Gestational trophoblastic diseases (GTDs) have not been investigated for their epigenetic marks and consequent transcriptomic changes. Here, we analyzed genome-wide DNA methylation and transcriptome data to reveal the epigenetic basis of disease pathways that may lead to benign or malignant GTDs. RNA-Seq, mRNA microarray, and Human Methylation 450 BeadChip data from complete moles and choriocarcinoma cells were bioinformatically analyzed. Paraffin-embedded tissues from complete moles and control placentas were used for tissue microarray construction, DNMT3B immunostaining and immunoscoring. We found that DNA methylation increases with disease severity in GTDs. Differentially expressed genes are mainly upregulated in moles while predominantly downregulated in choriocarcinoma. DNA methylation principally influences the gene expression of villous trophoblast differentiation-related or predominantly placenta-expressed genes in moles and choriocarcinoma cells. Affected genes in these subsets shared focal adhesion and actin cytoskeleton pathways in moles and choriocarcinoma. In moles, cell cycle and differentiation regulatory pathways, essential for trophoblast/placental development, were enriched. In choriocarcinoma cells, hormone biosynthetic, extracellular matrix-related, hypoxic gene regulatory, and differentiation-related signaling pathways were enriched. In moles, we found slight upregulation of DNMT3B protein, a developmentally important de novo DNA methylase, which is strongly overexpressed in choriocarcinoma cells that may partly be responsible for the large DNA methylation differences. Our findings provide new insights into the shared and disparate molecular pathways of disease in GTDs and may help in designing new diagnostic and therapeutic tools.