Different expression of placental pyruvate kinase in normal,preeclamptic and intrauterine growth restriction pregnancies

IntroductionPreeclampsia (PE) and intrauterine growth restriction (IUGR) are two diseases that affect pregnant women and their unborn children. These diseases cause low birth weight, pre-term delivery, and neurological and cardiovascular disorders in babies. Combined they account for 20% of preterm deliveries. Pyruvate kinase M2 (PKM2) is a metabolism enzyme found in developing embryonic and cancer tissues. Our objective is to determine the expression of PKM2 in human PE and IUGR compared to normal pregnancies. Understanding expression of PKM2 in PE and IUGR could help us to better understand the mechanisms and find treatments for PE and IUGR.MethodsHuman placental tissues were obtained for PKM2 determination and analyzed by immunohistochemistry, Western blot, and a pyruvate assay. Placental samples were homogenized and cytoplasmic and nuclear proteins were extracted for Western blot analysis.ResultsPreeclampsia samples had elevated levels of p-PKM2, p-ERK, and ERK in the cytoplasm. Beta-catenin and lactose dehydrogenase (LDH) were also elevated in preeclampsia placenta samples.Discussion and conclusionWe conclude that PKM2 is expressed in normal, PE and IUGR pregnancies. Also, that this expression is increased in the PE placenta at delivery. These results suggest placental metabolism through PKM2 could play a role in human preeclampsia.     

Association of first-trimester angiogenic factors with placental histological findings in late-onset preeclampsia

ObjectiveTo explore in women with late-onset preeclampsia (PE) the association between maternal levels of angiogenic/antiangiogenic factors in the first trimester of pregnancy and histological findings attributable to placental underperfusion (PUP).MethodsA nested case-control cohort study was conducted in 73 women with pregnancies complicated by late-onset PE (>34 weeks at delivery) matched with controls. First trimester uterine artery Doppler (UtA); maternal levels of placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt-1) were retrieved. Placentas were histologically evaluated using a hierarchical and standardized classification system. One-way ANOVA with linear polynomial contrast or linear-by-linear association test was performed to test the hypothesis of a linear association across study groups (controls, PE without PUP and PE with PUP).ResultsIn 54 (74%) placentas, 89 placental histological findings qualifying for PUP were found. Across study groups, significant values were observed in maternal levels of decreased PlGF (MoM values: 1.53, 1.41 and 1.37; p < 0.001), increased sFlt-1 (MoM values: 3.11, 3.11 and 3.22; p = 0.002), increased sFlt-1/PlGF ratio (MoM values: 2.3, 2.3 and 2.44; p < 0.001), abnormal UtA Doppler (MoM values: 1, 1.26 and 1.32; p < 0.001), and worse perinatal outcomes in terms of gestational age at delivery, cesarean section for not reassuring fetal status, birth weight and neonatal acidosis.DiscussionIn late-onset PE an imbalance of circulating angiogenic and anti-angiogenic factors already present at 8–10 weeks of pregnancy was associated with histological findings reflecting placental insufficiency. An early first trimester screening by angiogenic factors might help to identify patients with placental involvement among late-onset PE cases.ConclusionIn late-onset preeclampsia, first-trimester uterine Doppler and circulating levels of angiogenic/antiangiogenic factors are associated with placental underperfusion.     

Protective proteins and telomere length in placentas from patients with pre-eclampsia in the last trimester of gestation

IntroductionVisfatin/nicotinamide phosphoribosyltransferase (Nampt), an enzyme involved in energy metabolism and sirtuins, SIRT1 and SIRT3, which are NAD-dependent deacetylases, are critical for cellular function. All three either regulate or are regulated by intracellular NAD+ levels and therefore available cellular energy, important for placental cell survival and successful pregnancy. This study investigates whether these protective proteins are involved in the placental pathophysiology of pre-eclampsia (PE) and if they are associated with 8-oxo-deoxyguanosine (8OHdG), a marker of oxidative damage or with placental telomere length.MethodsMaternal blood and placental samples were collected from 31 patients with PE and 30 controls between 31 and 40 weeks gestation. Quantitative immunohistochemistry was performed on placental specimens for visfatin/Nampt, SIRT1, SIRT3, and nuclear 8OHdG. Plasma visfatin was measured by ELISA and telomere length by Southern blot analysis of telomere restriction fragments.ResultsVisfatin/Nampt and SIRT1 in syncytiotrophoblast decreased in PE compared to controls (p < 0.0001, p = 0.004 respectively). SIRT3 decreased in PE most significantly at preterm (p = 0.002). 8OHdG was only significantly lower in preterm controls compared to term controls (p = 0.01) and correlated with SIRT1 in all samples (r = 0.27). Telomere length was not different in PE and controls.DiscussionDecreased visfatin/Nampt, SIRT1 and SIRT3 in syncytiotrophoblast in PE suggests a lack of placental reserve in metabolic energy efficiency, increased inflammation, and lower resistance to environmental stressors. However, there was little effect on nuclear function, or evidence of genomic DNA damage, which would lead to cellular senescence and death.     

Impact of early- and late-onset preeclampsia on features of placental and newborn vascular health

IntroductionOffspring exposed to preeclampsia (PE) show an increased risk of cardiovascular disease in adulthood. We hypothesize that this is mediated by a disturbed vascular development of the placenta, umbilical cord and fetus. Therefore, we investigated associations between early-onset PE (EOPE), late-onset PE (LOPE) and features of placental and newborn vascular health.MethodsWe performed a nested case-control study in The Rotterdam Periconceptional Cohort, including 30 PE pregnancies (15 EOPE, 15 LOPE) and 218 control pregnancies (164 uncomplicated controls, 54 complicated controls including 28 fetal growth restriction, 26 preterm birth) and assessed macroscopic and histomorphometric outcomes of the placenta and umbilical cord.ResultsA significant association was observed between PE and a smaller umbilical vein area and wall thickness, independent of gestational age and birth weight. In EOPE we observed significant associations with a lower weight, length and width of the placenta, length of the umbilical cord, and thickness and wall area of the umbilical vein and artery. These associations attenuated after gestational age and birth weight adjustment. In LOPE a significant association with a larger placental width and smaller umbilical vein wall thickness was shown, independent of gestational age and birth weight.DiscussionOur study suggests that PE is associated with a smaller umbilical cord vein area and wall thickness, independent of gestational age and birth weight, which may serve as a proxy of disturbed cardiovascular development in the newborn. Follow-up studies are needed to ultimately predict and lower the risk of cardiovascular disease in offspring exposed to PE.     

Increased placental phospholipase A2 gene expression and free F2-isoprostane levels in response to oxidative stress in preeclampsia

Vasoactive eicosanoids such as thromboxane (TX) A₂ and F₂-isoprostanes (F₂-isoPs) were shown to be increased in the preeclamptic placenta. Only one of the 64 possible isomers of F₂-isoPs derived from the oxidation of arachidonic acid was investigated in the placenta so far. F₂-isoPs are released from membrane phospholipids by phospholipases A₂ (PLA₂) and were shown to act on the TXA₂ receptor (TBXA2R). However, the PLA₂ deregulated in preeclampsia (PE) remains to be determined. In this study, we analyzed the concentrations of six isomers of F₂-isoPs; 8-iso-PGF_2α, 8-iso-15(R)-PGF_2α, 15(R)-PGF_2α, iPF_2α-IV, iPF_2α-VI, 5-iPF_2α-VI and the concentrations of the stable metabolites of TXA₂, TXB_2, by high performance liquid chromatography coupled with tandem mass spectrometry in placentas of PE (n = 17) and normotensive (n = 15) pregnancies according to the biopsy site: peri-insertion or periphery. In the same biopsies, relative mRNA expression of PLA2G2A, PLA2G4A, PLA2G5, PLA2G7, the PLA2 receptor (PLA2R1), the TXA₂ synthase and TBXAR2 were measured by quantitative RT-PCR. We observed similar concentrations of total F₂-isoP isomers between groups whereas higher concentrations (>40%) of free F₂-isoP were observed for all isomers (p ≤ 0.033) in PE than normotensive controls. As expected, we also observed higher placental concentrations of TXB₂ in PE (p = 0.005). Interestingly, we concomitantly found higher mRNA expression of secretory PLA2G2A (p = 0.010), PLA2G5 (p = 0.038) and TBXA2R (p = 0.023) in PE than normotensive placentas. In sum, deregulated PLA₂ could potentially be implicated in freeing F₂-isoP which could participate in local hypertension observed in the PE placenta through the TX pathway.     

YAP mediates human decidualization of the uterine endometrial stromal cells

IntroductionThe decidualization of uterine endometrial stromal cells (ESCs) is critical for the successful establishment and maintenance of pregnancy and involves extensive cell proliferation and differentiation. A newly established signaling pathway, the Hippo/Yes-associated protein (YAP) pathway, plays a critical role in these proliferation processes. Our previous study demonstrated that YAP is expressed in human ESCs. However, its role in decidualization remains unclear. The objective of the present study was to explore the role of YAP in the decidualization of human ESCs.MethodsThe expression of YAP was first investigated in the endometrium of non-pregnant women and in the decidua of pregnant women. The role of YAP was investigated by transfecting ESCs with mRNA silencing constructs and observing the negative effects of this action upon decidualization induced in vitro.ResultsOur results revealed that the expression of YAP was higher in decidual cells from early pregnant decidua compared with ESCs from non-pregnant endometrium. The expression levels of YAP and TEA domain 1 (TEAD1) were both increased in ESCs during in vitro decidualization and the knockdown of YAP in ESCs caused negative effects upon decidualization in vitro.DiscussionOur study suggests that YAP is upregulated in human decidual cells compared with ESCs and influences the decidualization of ESCs.     

Porphyromonas gingivalis induces IL-8 and IFN-gamma secretion and apoptosis in human extravillous trophoblast derived HTR8/SVneo cells via activation of ERK1/2 and p38 signaling pathways

IntroductionPreterm birth is a major cause for infant mortality and morbidity. A large number of studies have suggested a link between periodontal disease and preterm birth. The purpose of this study was to investigate the interaction between a periodontopathic bacterium Porphyromonas gingivalis and human extravillous trophoblast derived HTR8/SVneo cells.MethodsProduction of cytokines in HTR8 cells was measured via ELISA. Annexin V/PI flow cytometry was performed to assess apoptosis. Protein expression was measured by western blot. Specific pharmacological inhibitors were used to inactivate relevant signaling pathways (p38 MAPK, SB203580; ERK1/2, U0126; JNK, SP600125; NF-κB, JSH-23) to determine their roles in inflammation and apoptosis.ResultsHTR8 cells released significant amounts of IL-8 and IFN-γ during exposure to P. gingivalis. Meanwhile, the percentages of both early and late apoptotic cells increased significantly in response to P. gingivalis. The most significant effect on inflammation was found using SB203580 and U0126, followed by SP600125 and JSH-23. Moreover, U0126 and SB203580 both partially but significantly suppressed P. gingivalis-induced apoptosis, with a large effect by U0126. Additionally, both heat-killed P. gingivalis and P. gingivalis lipopolysaccharide significantly induced IL-8 production.ConclusionP. gingivalis induces inflammation and apoptosis in HTR8 cells, and we demonstrated for the first time that activation of ERK1/2 and p38 MAPK pathways participates in P. gingivalis-induced inflammation and apoptosis. The abnormal regulation of inflammation and apoptosis in human trophoblasts by P. gingivalis infection may give new insights into how maternal periodontal disease and periodontal pathogens might be linked to preterm birth.     

Endometrial androgen signaling and decidualization regulate trophoblast expansion and invasion in co-culture: A time-lapse study

IntroductionTo elucidate whether trophoblast expansion and invasion are modulated by androgen signaling in an in vitro co-culture model system with decidualizing endometrial stromal cells (ESCs).MethodsWe employed an in vitro co-culture model of early embryo implantation, consisting of human ESCs (EtsT499 cells) and spheroids generated by extravillous trophoblast (EVT) derived HTR8/Svneo. The ESCs were decidualized with 8-bromo-cAMP (8-br-cAMP) in the presence or absence of dihydrotestosterone (DHT) at various concentrations for 5 days before co-culture with EVT spheroids. Trophoblast expansion was monitored by fluorescent time-lapse imaging microscopy. ESCs motility was visualized by using CellTracker™ Orange CMRA fluorescent probe. Apoptosis of ESCs was detected by CellEvent™ Caspase-3/7^® green detection reagent. Invasion assays were performed to quantify EVT invasion through a chemotaxis cell membrane.ResultsExpansion of EVT spheroids was significantly enhanced by decidualized compared to undifferentiated ESCs. This process was further stimulated if ESCs were first decidualized in the presence of DHT. In contrast to decidualized ESCs, undifferentiated cells actively migrated away from expanding EVT spheroids. Invasiveness of EVT toward decidualized ESCs was significantly attenuated in comparison to undifferentiated ESCs. DHT had no effect on EVT invasion. However, an inhibitor of intercellular gap junction communication significantly enhanced EVT invasion towards decidualized ESCs.ConclusionsThese results indicate distinct roles for androgen signaling and gap junction formation in decidual cells in regulating trophoblast expansion and invasion.     

Increased placental trophoblast inclusions in placenta accreta

IntroductionTrophoblast inclusions (TIs) are often found in placentas of genetically abnormal gestations. Although best documented in placentas from molar pregnancies and chromosomal aneuploidy, TIs are also associated with more subtle genetic abnormalities, and possibly autism. Less than 3% of non-aneuploid, non-accreta placentas have TIs. We hypothesize that placental genetics may play a role in the development of placenta accreta and aim to study TIs as a potential surrogate indicator of abnormal placental genetics.MethodsForty cases of placenta accreta in the third trimester were identified in a search of the medical records at one institution. Forty two third trimester control placentas were identified by a review of consecutively received single gestation placentas with no known genetic abnormalities and no diagnosis of placenta accreta.ResultsForty percent of cases with placenta accreta demonstrated TIs compared to 2.4% of controls. More invasive placenta accretas (increta and percreta) were more likely to demonstrate TIs than accreta (47% versus 20%). Prior cesarean delivery was more likely in accreta patients than controls (67% versus 9.5%).DiscussionPlacenta accreta is thought to be the result of damage to the endometrium predisposing to abnormal decidualization and invasive trophoblast growth into the myometrium. However, the etiology of accreta is incompletely understood with accreta frequently occurring in women without predisposing factors and failing to occur in predisposed patients.ConclusionThis study has shown that TIs are present at increased rates in cases of PA. Further studies are needed to discern what underlying pathogenic mechanisms are in common between abnormal placentation and the formation of TIs.     

Dynamic maternal and fetal Notch activity and expression in placentation

IntroductionMurine placentation requires trophoblast Notch2, while the Notch ligand, JAGGED1, is reduced in invasive trophoblasts from women with preeclampsia. However, the placental cells with active Notch signaling and expression of other Notch proteins and ligands in placentation have yet to be defined. We sought to identify endothelial cell and trophoblast subtypes with canonical Notch signaling in the decidua and placenta and correlate this to expression of Notch proteins and ligands.MethodsNotch reporter transgenic mice were used to define canonical Notch activity and immunofluorescence staining performed to characterize expression of Notch1, 2, 3, 4 and ligands, Delta-like 4 (Dll4) and Jagged1 (Jag1) during early placentation and in the mature placenta.ResultsNotch signaling is active in maternal and fetal endothelial cells and trophoblasts during early placentation and in the mature placenta. Dll4, Jag1, Notch1, and Notch4 are expressed in maternal vasculature in the decidua. Dll4, Jag1 and Notch1 are expressed in fetal vasculature in the labyrinth. Dll4, Notch2 and Notch4 are co-expressed in the ectoplacental cone. Notch2 and Notch4 are expressed in parietal-trophoblast giant cells and junctional zone trophoblasts with active canonical Notch signaling and in labyrinthine syncytiotrophoblasts and sinusoidal-trophoblast giant cells.DiscussionCanonical Notch activity and distinct expression patterns for Notch proteins and ligands was evident in endothelium and trophoblasts, suggesting Notch1, Notch2, Notch4, Dll4, and Jag1 have distinct and overlapping functions in placentation. Characterization of Notch signaling defects in existing mouse models of preeclampsia may shed light on the role of Notch in developing the preeclampsia phenotype.     

The granulocyte colony-stimulating factor (G-CSF) upregulates metalloproteinase-2 and VEGF through PI3K/Akt and Erk1/2 activation in human trophoblast Swan 71 cells

IntroductionAlthough the expression of the granulocyte colony-stimulating factor (G-CSF) and its receptor (G-CSFR) in placental tissues suggests that the cytokine could play a role in placental development, the relevance of G-CSF:G-CSFR interaction in trophoblast cells remains to be studied. Thus, the possible functional role of G-CSF was examined in a human trophoblast cell line (Swan 71 cells).Methods and resultsThe expression of G-CSFR was detected by immunocytochemistry and Western blot assays. G-CSF treatment exerted neither a proliferative nor a protective effect on H₂O₂-mediated cell death in trophoblast cells. Gelatin zymography of supernatants collected from G-CSF-treated cells showed an increment of metalloproteinase-2 (MMP-2) activity. We also found higher MMP-2 and VEGF expression levels in conditioned medium from cells exposed to G-CSF. In addition, it was demonstrated that G-CSF induced the activation of PI3K/Akt and Erk1/2 pathways, which in turn activated NF-kB. By using selective pharmacological inhibitors, it was showed that these pathways are mediating the biological effects produced by G-CSF in Swan 71 cells.Discussion and conclusionWe have demonstrated for the first time that G-CSF increases MMP-2 activity and VEGF secretion in Swan 71 cells through activation of PI3K/Akt and Erk signaling pathways, both contributing to the translocation of NF-kB to the nucleus. These data suggest that G-CSF is involved in the regulation of trophoblast function, and should be considered as a locally produced cytokine probably contributing to embryo implantation and the development of a functional placenta.     

Mouse prolyl oligopeptidase plays a role in trophoblast stem cell differentiation into trophoblast giant cell and spongiotrophoblast

IntroductionProlyl oligopeptidase (prolyl endopeptidase, Prep), a multifunctional protease hydrolyzing -Pro-X- peptide bonds, is highly expressed in the mouse placenta, but the function during development is not known. We explored the possibility of Prep's involvement in placental differentiation.MethodsWe cultured trophoblast stem cells (TSCs) derived from the E6.5 mouse embryo and investigated the detailed expression pattern of Prep during their differentiation. Prep-specific inhibitors were added to the TSC culture, and the effect on the differentiation was assessed by microscopic observation and the expression of marker gene for each placental cell.ResultsDuring TSC differentiation for 6 days, Prep was constantly detected at mRNA, protein, and activity levels, and the protein was found mainly in the cytoplasm. The addition of 30 μM and 10 μM SUAM-14746, a Prep-specific inhibitor, effectively inhibited the differentiation into spongiotrophoblasts (SpTs) and trophoblast giant cells (TGCs), while the TSC viability was not affected. 5 μM SUAM-14746 impaired the differentiation into SpTs, and 1 μM SUAM-14746 exhibited no effects. Another Prep-specific inhibitor, KYP-2047, did not affect the differentiation. We confirmed efficient inhibition of Prep enzymatic activity in TSCs by both inhibitors.ConclusionThe dose-dependent effect of SUAM-14746 on TSCs suggests that Prep plays an important role in the differentiation into SpTs and TGCs in the mouse placenta.     

Transendothelial migration of human umbilical mesenchymal stem cells across uterine endothelial monolayers: Junctional dynamics and putative mechanisms

IntroductionDuring pregnancy, fetal stem cells can transfer to the maternal circulation and participate in tissue repair. How they transmigrate across maternal endothelial barriers and whether they can subsequently influence maternal endothelial integrity is not known.MethodsMesenchymal stem cells (WJ-MSC) were isolated from Wharton's jelly and their interactions with human uterine microvascular endothelial cell (HUtMEC) monolayers, junctional occupancy and expression/phosphorylation of vascular endothelial (VE)- cadherin and vascular endothelial growth factor (VEGF-A) secretion was studied over 48h by real time, confocal microscopy, immunoblotting and ELISA.ResultsWJ-MSC displayed exploratory behaviour with interrogation of paracellular openings and spreading into the resultant increased gaps followed by closing of the endothelium over the WJ-MSC. 62% of added cells crossed within 22h to sub-endothelial niches. There was a concomitant loss of junctional VE-cadherin in HUtMEC followed by a full return and increased VE-cadherin expression after 22h. During early hours, VE-cadherin showed a transient phosphorylation at Tyrosine (Tyr)-685 when VEGF-A secretion were high. From 16 to 22h, there was increased de-phosphorylation of Tyr-731. Anti-VEGF-A blocked Tyr-685 phosphorylation but not the decrease in P-Tyr731; this partially inhibited WJ-MSC transmigration.DiscussionFetal WJ-MSC can traverse uterine endothelial monolayers by mediating a non-destructive paracellular pathway. They can promote junctional stability of uterine endothelium from the sub-endothelial niche. Mechanistically, WJ-MSC induces VEGF-dependent phosphorylation events linked with paracellular permeability and VEGF-independent de-phosphorylation events associated with leukocyte extravasation. Our data also allows consideration of a possible role of fetal MSC in mature functioning of the uterine vasculature needed for optimal utero-placental perfusion.     

Maternal obesity induced by a ‘cafeteria’ diet in the rat does not increase inflammation in maternal,placental or fetal tissues in late gestation

IntroductionObesity during pregnancy can cause serious complications for maternal and infant health. While this has often been attributed to increased inflammation during obese pregnancy, human and animal studies exhibit variable results with respect to the inflammatory status of the mother, placenta and fetus. Cafeteria (CAF) feeding induces more inflammation than standard high-fat feeding in non-pregnant animal models. This study investigated whether maternal obesity induced by a CAF diet increases maternal, fetal or placental inflammation.MethodsMaternal obesity was established in rats by 8 weeks of pre-pregnancy CAF feeding. Maternal plasma inflammatory markers (IL-1β, IL-6, IL-10, IL-12p40, MCP1, GRO/KC, MIP-2 and TNFα) and expression of inflammatory genes (Tnfα, Il-6, Il-1β, Tlr2, Tlr4, Cox2 and Emr1) in maternal, placental and fetal tissues were measured at day 21 of gestation.ResultsDespite CAF animals having 63% more central body fat than controls at day 21 of gestation, plasma inflammatory markers were not increased; indeed, levels of IL-6, IL-12p40 and MIP2 were reduced slightly. Similarly, inflammatory gene expression remained largely unaffected by CAF feeding, except for slight reductions to Tlr4 and Emr1 expression in CAF maternal adipose tissue, and reduced Tlr4 expression in male labyrinth zone (LZ). The junctional zone (JZ) displayed increased Il-6 expression in CAF animals when fetal sexes were combined, but no inflammatory genes were affected by the CAF diet in fetal liver.ConclusionsMaternal obesity induced by a CAF diet before and during pregnancy does not increase the inflammatory status of the mother, placenta or fetus in late gestation.