Remodeling Of Maternal Spiral Arteries Research Articles

HLA-G isoforms, HLA-C allotype and their expressions differ between early abortus and placenta in relation to spontaneous abortions

IntroductionSpontaneous abortion (SAB) affects approximately 10% of clinically recognized pregnancies. Fetal trophobalst invasion and remodeling of maternal spiral arteries is reported to be dependent on crosstalk between HLA-C/HLA-G expressed on extra villous trophoblast (EVTs)and Killer cell Immunoglobin like receptors (KIRs) of decidual NK (dNK). Immune dysfunction in decidua contributes to early miscarriage. MethodologyThe study used mother neonate paired cord blood and term placenta samples (n = 46), elective abortus (n = 17,gestational age = 10–12 weeks of pregnancy) and SAB abortus (n = 24, gestational age = 12–15 weeks of pregnancy) for HLA-G, KIR2D and HLA-C. In addition, term placenta was collected from women with history of spontaneous pregnancy loss (n = 24) and women with history of live birth (n = 32). SSP-PCR was used for genotyping, RT-PCR for gene expression, copy number variation (CNVs) and HLA-C allotyping and ELISA for protein expression studies. ResultsMembrane bound HLA-G4 isoform proportion was higher 39.28%, p = 0.02) in term placenta. SAB abortus had higher proportion of HLA-G3 (50%),while elective abortus exhibited higher proportion of soluble isoforms (HLA-G5, = 5.9, HLA-G6 = 5.9%, HLA-G7 = 11.8%).Higher inhibitory KIR2DL1 content and copy numbers with lower HLA-C2 in SAB contrasted with higher copy numbers of KIR2DS1(p = 0.001), KIR2DS1+/2DL1+- HLA-C2 combined genotype in healthy placenta. Elevated KIR2D protein levels (p = 0.001), and concurrently, HLA-C levels were upregulated in healthy placenta. ConclusionOur data supports lower cognate receptor ligand KIR2DS1+/2DL1+ HLA–C2 together with predominance of HLA-G3 isoform in SAB as confounding factors in spontaneous pregnancy loss. HLA-G isoforms and expression differed between first trimester abortus and term placenta suggesting temporal modulation and marks novelty of the study.

Hypertensive Disorders of Pregnancy and the Cardiovascular System: Causes, Consequences, Therapy, and Prevention.

Hypertensive disorders of pregnancy continue to be significant contributors to adverse perinatal outcome and maternal mortality, as well as inducing life-long cardiovascular health impacts that are proportional to the severity and frequency of pregnancy complications. The placenta is the interface between the mother and fetus and its failure to undergo vascular maturation in tandem with maternal cardiovascular adaptation by the end of the first trimester predisposes to hypertensive disorders and fetal growth restriction. While primary failure of trophoblastic invasion with incomplete maternal spiral artery remodeling has been considered central to the pathogenesis of preeclampsia, cardiovascular risk factors associated with abnormal first trimester maternal blood pressure and cardiovascular adaptation produce identical placental pathology leading to hypertensive pregnancy disorders. Outside pregnancy blood pressure treatment thresholds are identified with the goal to prevent immediate risks from severe hypertension >160/100 mm Hg and long-term health impacts that arise from elevated blood pressures as low as 120/80 mm Hg. Until recently, the trend for less aggressive blood pressure management during pregnancy was driven by fear of inducing placental malperfusion without a clear clinical benefit. However, placental perfusion is not dependent on maternal perfusion pressure during the first trimester and risk-appropriate blood pressure normalization may provide the opportunity to protect from the placental maldevelopment that predisposes to hypertensive disorders of pregnancy. Recent randomized trials set the stage for more aggressive risk-appropriate blood pressure management that may offer a greater potential for prevention for hypertensive disorders of pregnancy. KEY POINTS: · Optimal management of maternal blood pressure to prevent preeclampsia and its risks is undefined.. · Early gestational rheological damage to the intervillous space predisposes to preeclampsia and FGR.. · First trimester blood pressure management may need to aim for normotension to prevent preeclampsia..

Cyclin G2 Is Involved in the Proliferation of Placental Trophoblast Cells and Their Interactions with Endothelial Cells

BackgroundRemodeling of maternal spiral arteries after embryo implantation relies on well-regulated trophoblast functions. Although cyclin G2 (CCNG2) is thought to be involved in placental development and function, its role in trophoblasts and the mechanisms underlying placental development and function remain unclear. The present study investigated the potential role of CCNG2 in trophoblast cell proliferation and their interactions with endothelial cells.Material/MethodsCCNG2 levels were modified by stable infection of HTR8/SVneo cells with lentiviruses overexpressing and silencing CCNG2. Cell proliferation was measured using CCK-8 assays. Network formation assays were performed using trophoblasts alone and co-cultured trophoblasts and endothelial cells to measure angiogenesis of trophoblasts and trophoblast-endothelial interactions. Levels of angiogenic factors (VEGF and sFlt-1) in the supernatant were measured by ELISA, and the expression of cell cycle regulatory (cyclin D1) and invasive (MMP2, MMP3, MMP9) markers implicated in artery remodeling were measured by western blotting.ResultsEctopic expression of CCNG2 blocked the proliferation of HTR8/SVneo cells, as well as their abilities to form networks and integrate into human umbilical vein endothelial cells, whereas CCNG2 inhibition had the opposite effects. CCNG2 upregulation significantly reduced the expression of VEGF, cyclin D1, MMP2, MMP3, and MMP9, but enhanced the expression of sFlt-1. In contrast, CCNG2 downregulation had the opposite effects.ConclusionsCCNG2 plays a critical role in trophoblast proliferation and trophoblast-endothelial cell interactions by significant affecting cell cycle, angiogenic, and invasive markers. CCNG2 may thus be a novel marker for the treatment of placental disorders.

Long non‑coding RNA NR_002794 is upregulated in pre‑eclampsia and regulates the proliferation, apoptosis and invasion of trophoblast cells.

Pre-eclampsia is a common complication during pregnancy, characterized by hypertension and proteinuria. The pathogenesis of pre-eclampsia is not fully understood. Studies on the maternal spiral artery have led scientists to consider that the ineffective infiltration of placental trophoblast cells may be a primary cause of pre-eclampsia. The present study aimed to investigate the differences in the profiles of long non-coding RNAs (lncRNAs) between the placentas of patients with pre-eclampsia and those of healthy pregnant women. The involvement of the differentially expressed lncRNAs in the biological activity of trophoblast cells was also assessed. A total of 26 differentially expressed lncRNAs were identified between the pre-eclampsia and healthy groups. Upregulation of NR_002794 was found in tissues from patients with pre-eclampsia. In SWAN71 trophoblast cells, NR_002794 had suppressive effects on proliferation and migration, and resulted in an increased rate of apoptosis. Furthermore, lncRNA NR_002794 had no effect on the phagocytosis of trophoblast cells. The present study suggested that abnormal levels of NR_002794 may lead to atypical conditions in trophoblast cells, which may be associated with the failure of maternal spiral artery remodeling during pregnancy and, consequently, with the development of pre-eclampsia.

UNK cell-derived TGF-β1 regulates the long noncoding RNA MEG3 to control vascular smooth muscle cell migration and apoptosis in spiral artery remodeling.

Successful pregnancy depends on correct spiral artery (SpA) remodeling, and thus, on normal patterns of the vascular smooth muscle cell (VSMC) apoptosis and migration. Uterine natural killer (uNK) cells-derived transforming growth factor β1 (TGF-β1) is known to mediate the separation of VSMC layers via as yet unknown mechanisms. Likewise, the long noncoding RNA maternally expressed gene 3 (MEG3) is a tumor suppressor that has been shown to regulate cancer cell apoptosis and migration; however, its role in VSMC loss is unclear. Thus, the aim of the present study was to assess the effects of uNK-derived TGF-β1 and MEG3 on VSMC function during SpA. Analyses were conducted to assess the effects of downregulating MEG3 expression, and/or administering treatments to increase or block TGF-β1 signaling on VSMC survival and behavior. The results of these analyses showed that treating the VSMC with uNK cell-derived supernatant or recombinant human TGF-β1 promoted MEG3 and matrix metalloprotease 2 expression and VSMC apoptosis and migration, and suppressed VSMC proliferation. Conversely, MEG3 silencing promoted VSMC proliferation and inhibited VSMC apoptosis and migration. Notably, TGF-β1 signaling induction had no significant effect on the proliferation, apoptosis, nor migration of the MEG3-silenced VSMC. Together, these findings suggest that MEG3 is regulated by uNK-derived TGF-β1, and itself mediates VSMC apoptosis and migration; thus, it may be an important positive regulator of VSMCs separation during maternal SpA remodeling.

Low-Density Lipoprotein Receptor-Related Protein 6 Is Essential for Trophoblast Survival and Invasion.

Remodeling of maternal spiral artery after the implantation of embryo relies on tightly regulated trophoblast functions and is pivotal to ensure the success of pregnancy. Low-density lipoprotein receptor-related protein 6 (LRP6) is implicated in angiogenesis and several vascular diseases, but its function in trophoblast regulation is still not fully understood. We aimed to investigate the involvement of LRP6 in trophoblast functions during maternal spiral artery remodeling. HTR-8/SVneo cells, a trophoblast cell line, were employed to examine the impact of LRP6 knockdown on proliferation, apoptosis, and migration, as well as invasion and tube formation. Expression of matrix metalloproteinases (MMPs), angiogenic factors placental growth factor (PlGF), and vascular endothelial growth factor (VEGF), as well as activation of canonical Wnt/β-catenin signaling pathway, which was involved in artery remodeling process, was also analyzed. Lipoprotein receptor-related protein 6 knockdown suppressed proliferation, migration, invasion, and tube formation, as well as induced apoptosis in HTR-8/SVneo cells. In addition, LRP6 knockdown also significantly decreased expression of MMPs, PlGF, and VEGF and activation of Wnt/β-catenin signaling pathway. Lipoprotein receptor-related protein 6 might positively regulate the remodeling of the maternal artery through both endovascular formation and trophoblast invasion.

MicroRNA-590-3p inhibits trophoblast-dependent maternal spiral artery remodeling by repressing low-density lipoprotein receptor-related protein 6.

BackgroundThe remodeling of maternal spiral artery following embryo implantation, which relies on well‐regulated trophoblast functions, is a pivotal process to ensure a successful pregnancy. Low‐density lipoprotein receptor‐related protein 6 (LRP6) and microRNAs (miRNAs, miRs) are suggested to be involved in angiogenesis and several vascular diseases; however, their functions in the control of trophoblast remain elusive. We therefore aimed to examine the roles of LRP6 and miR‐590‐3p in the regulation of trophoblast during the remodeling of maternal spiral artery.MethodsHTR‐8/SVneo cell, a trophoblast cell line, was utilized to study the effects of LRP6 and miR‐590‐3p on apoptosis, cell proliferation, migration, invasion, as well as tube formation. Expression of angiogenic factors placental growth factor (PlGF), matrix metalloproteinases (MMPs), vascular endothelial growth factor (VEGF), and activities of canonical Wnt/β‐catenin signaling pathway, which were implicated in the process of artery remodeling, were also examined.ResultsMiR‐590‐3p directly targeted 3′ untranslated region (3′‐UTR) of LRP6 mRNA and repressed LRP6 expression, which in turn inhibited proliferation, migration, invasion, as well as tube formation, and resulted in apoptosis in HTR‐8/SVneo cells. Further, inhibition of LRP6 through miR‐590‐3p significantly suppressed the expression of PlGF, MMPs, and VEGF and reduced the activation of Wnt/β‐catenin signaling pathway.ConclusionMicroRNAs‐590‐3p may inhibit trophoblast‐dependent maternal spiral artery remodeling, via both trophoblast invasion and endovascular formation, by repressing LRP6.

Effects of selective serotonin-reuptake inhibitors (SSRIs) in JEG-3 and HIPEC cell models of the extravillous trophoblast

IntroductionBetween 2 and 10% of pregnant women are treated with selective serotonin-reuptake inhibitors (SSRIs) for depression. The extravillous trophoblasts (evTBs), which migrate and invade maternal tissues, are crucial for embryo implantation and remodeling of maternal spiral arteries. Poor migration/invasion of evTBs can cause serious pregnancy complications, yet the effects of SSRIs on these processes has never been studied. To determine the effects of five SSRIs (fluoxetine, norfluoxetine, citalopram, sertraline and venlafaxine) on migration/invasion, we used JEG-3 and HIPEC cells as evTB models. MethodsCells were treated with increasing concentrations (0.03–10 μM) of SSRIs. Cell proliferation was monitored using an impedance-based system and cell cycle by flow cytometry. Migration was determined using a scratch test, and metalloproteinase (MMP) activities, by zymography. Invasion markers were determined by RT-qPCR. ResultsFluoxetine and sertraline (10 μM) significantly decreased cell proliferation by 94% and by 100%, respectively, in JEG-3 cells, and by 58.6% and 100%, respectively, in HIPEC cells. Norfluoxetine increased MMP-9 activity in JEG-3 cells by 2.0% at 0.03 μM and by 43.9% at 3 μM, but decreased MMP-9 activity in HIPEC cells by 63.7% at 3 μM. Sertraline at 0.03 μM increased mRNA level of TIMP-1 in JEG-3 cells by 36% and that of ADAM-10 by 85% and 115% at 0.3 and 3 μM, respectively. In HIPEC cells, venlafaxine at 0.03 and 0.3 μM, increased ADAM-10 mRNA levels by 156% and 167%, respectively. DiscussionThis study shows that SSRIs may affect evTBs homeostasis at therapeutic levels and provides guidance for future research.

Early first trimester uteroplacental flow and the progressive disintegration of spiral artery plugs: new insights from contrast-enhanced ultrasound and tissue histopathology.

Does the use of a vascular contrast agent facilitate earlier detection of maternal flow to the placental intervillous space (IVS) in the first trimester of pregnancy? Microvascular filling of the IVS was demonstrated by contrast-enhanced ultrasound from 6 weeks of gestation onwards, earlier than previously believed. During placental establishment and remodeling of maternal spiral arteries, endovascular trophoblast cells invade and accumulate in the lumen of these vessels to form 'trophoblast plugs'. Prior evidence from morphological and Doppler ultrasound studies has been conflicting as to whether the spiral arteries are completely plugged, preventing maternal blood flow to the IVS until late in the first trimester. Uteroplacental flow was examined across the first trimester in human subjects given an intravenous infusion of lipid-shelled octofluoropropane microbubbles with ultrasound measurement of destruction and replenishment kinetics. We also performed a comprehensive histopathological correlation using two separately archived uteroplacental tissue collections to evaluate the degree of spiral artery plugging and evaluate remodeling of the upstream myometrial radial and arcurate arteries. Pregnant women (n = 34) were recruited in the first trimester (range: 6+3 to 13+6 weeks gestation) for contrast-enhanced ultrasound studies with destruction-replenishment analysis of signal intensity for assessment of microvascular flux rate. Histological samples from archived in situ (Boyd Collection, n = 11) and fresh first, second, and third trimester decidual and post-hysterectomy uterine specimens (n = 16) were evaluated by immunohistochemistry (using markers of epithelial, endothelial and T-cells, as well as cell adhesion and proliferation) and ultrastructural analysis. Contrast agent entry into the IVS was visualized as early as 6+3 weeks of gestation with some variability in microvascular flux rate noted in the 6-7+6 week samples. Spiral artery plug canalization was observed from 7 weeks with progressive disintegration thereafter. Of note, microvascular flux rate did not progressively increase until 13 weeks, which suggests that resistance to maternal flow in the early placenta may be mediated more proximally by myometrial radial arteries that begin remodeling at the end of the first trimester. Gestational age was determined by crown-rump length measurements obtained by transvaginal ultrasound on the day of contrast-enhanced imaging studies, which may explain the variability in the earliest gestational age samples due to the margin of error in this type of measurement. Our comprehensive in situ histological analysis, in combination with the use of an in vivo imaging modality that has the sensitivity to permit visualization of microvascular filling, has allowed us to reveal new evidence in support of increasing blood flow to the IVS from 6 weeks of gestation. Histologic review suggested the mechanism may be blood flow through capillary-sized channels that form through the loosely cohesive 'plugs' by 7 weeks gestation. However, spiral artery remodeling on its own did not appear to explain why there is significantly more blood flow at 13 weeks gestation. Histologic studies suggest it may be related to radial artery remodeling, which begins at the end of the first trimester. This project was supported by the Oregon Health and Science University Knight Cardiovascular Institute, Center for Developmental Health and the Struble Foundation. There are no competing interests.

Manifestations of Hypoxia in the Second and Third Trimester Placenta.

The placental pathologies that develop in the context of hypoxic insults to the fetus and placenta are termed maternal vascular malperfusion (MVM). On molecular analysis, these lesions primarily show evidence of oxidative damage, suggesting that they arise in the context of hypoxia-reperfusion injury. The earliest abnormalities are likely incomplete or absent remodeling of maternal spiral arteries (decidual arteriopathy). These vascular remodeling defects then lead to subsequent damage patterns, including accelerated villous maturation, distal villous hypoplasia, increased syncytial knots, villous infarction, retroplacental hemorrhage, and placental hypoplasia. MVM may occur in a surprisingly wide array of clinical disorders, but the relation between these clinical disorders and placental MVM is complex. It seems likely that these clinical disorders represent final common pathways for multiple etiologies, only some of which result in MVM. Birth Defects Research 109:1345-1357, 2017.© 2017 Wiley Periodicals, Inc.

Placental Hypoxia During Early Pregnancy Causes Maternal Hypertension and Placental Insufficiency in the Hypoxic Guinea Pig Model.

Chronic placental hypoxia is one of the root causes of placental insufficiencies that result in pre-eclampsia and maternal hypertension. Chronic hypoxia causes disruption of trophoblast (TB) development, invasion into maternal decidua, and remodeling of maternal spiral arteries. The pregnant guinea pig shares several characteristics with humans such as hemomonochorial placenta, villous subplacenta, deep TB invasion, and remodeling of maternal arteries, and is an ideal animal model to study placental development. We hypothesized that chronic placental hypoxia of the pregnant guinea pig inhibits TB invasion and alters spiral artery remodeling. Time-mated pregnant guinea pigs were exposed to either normoxia (NMX) or three levels of hypoxia (HPX: 16%, 12%, or 10.5% O2) from 20 day gestation until midterm (39–40 days) or term (60–65 days). At term, HPX (10.5% O2) increased maternal arterial blood pressure (HPX 57.9 ± 2.3 vs. NMX 40.4 ± 2.3, P < 0.001), decreased fetal weight by 16.1% (P < 0.05), and increased both absolute and relative placenta weights by 10.1% and 31.8%, respectively (P < 0.05). At midterm, there was a significant increase in TB proliferation in HPX placentas as confirmed by increased PCNA and KRT7 staining and elevated ESX1 (TB marker) gene expression (P < 0.05). Additionally, quantitative image analysis revealed decreased invasion of maternal blood vessels by TB cells. In summary, this animal model of placental HPX identifies several aspects of abnormal placental development, including increased TB proliferation and decreased migration and invasion of TBs into the spiral arteries, the consequences of which are associated with maternal hypertension and fetal growth restriction.

Assessment of Maternal Vascular Remodeling During Pregnancy in the Mouse Uterus.

The placenta mediates the exchange of factors such as gases and nutrients between mother and fetus and has specific demands for supply of blood from the maternal circulation. The maternal uterine vasculature needs to adapt to this temporary demand and the success of this arterial remodeling process has implications for fetal growth. Cells of the maternal immune system, especially natural killer (NK) cells, play a critical role in this process. Here we describe a method to assess the degree of remodeling of maternal spiral arteries during mouse pregnancy. Hematoxylin and eosin-stained tissue sections are scanned and the size of the vessels analysed. As a complementary validation method, we also present a qualitative assessment for the success of the remodeling process by immunohistochemical detection of smooth muscle actin (SMA), which normally disappears from within the arterial vascular media at mid-gestation. Together, these methods enable determination of an important parameter of the pregnancy phenotype. These results can be combined with other endpoints of mouse pregnancy to provide insight into the mechanisms underlying pregnancy-related complications.

Assessment of Maternal Vascular Remodeling During Pregnancy in the Mouse Uterus

The placenta mediates the exchange of factors such as gases and nutrients between mother and fetus and has specific demands for supply of blood from the maternal circulation. The maternal uterine vasculature needs to adapt to this temporary demand and the success of this arterial remodeling process has implications for fetal growth. Cells of the maternal immune system, especially natural killer (NK) cells, play a critical role in this process. Here we describe a method to assess the degree of remodeling of maternal spiral arteries during mouse pregnancy. Hematoxylin and eosin-stained tissue sections are scanned and the size of the vessels analysed. As a complementary validation method, we also present a qualitative assessment for the success of the remodeling process by immunohistochemical detection of smooth muscle actin (SMA), which normally disappears from within the arterial vascular media at mid-gestation. Together, these methods enable determination of an important parameter of the pregnancy phenotype. These results can be combined with other endpoints of mouse pregnancy to provide insight into the mechanisms underlying pregnancy-related complications.

The effects of angiogenic growth factors on first trimester trophoblast invasion and proliferation

Maternal spiral artery remodeling after embryo implantation is a crucial process for successful pregnancy and rely on well-controlled trophoblast functions. Ephrin-B2 is found to be of great importance in various cell functions in both benign human tissue and tumors. However, its role in the regulation of trophoblast remains unknown. This study is conducted to investigate the role of ephrin-B2-induced trophoblast functions related to artery remodeling.Trophoblast cell line HTR-8/SVneo was used to investigate the effects of ephrin-B2 inhibition on cell proliferation, apoptosis, migration, invasion and tube formation. Placental-decidual co-culture (PDC) system was conducted to verify ephrin-B2-induced trophoblast functions ex vivo. Factors involving in artery remodeling process, such as matrix metalloproteinases (MMPs), placental growth factors (PlGF) and vascular endothelial growth factor (VEGF) were tested at transcriptional level.Inhibition of ephrin-B2 suppressed cell proliferation and induced cell apoptosis in HTR-8/SVneo cells. Down-regulation of ephrin-B2 impaired migration/invasion capabilities of HTR-8/SVneo cells and significantly decreased gene expression of MMPs. Also, a worse tube formation and a decrease in gene expression of PlGF was observed after down-regulation of ephrin-B2. However gene expression of VEGF-A did not show significantly statistical difference. These effects were further confirmed by PDC system showing an inadequate trophoblast invasion and spiral artery remodeling.Ephrin-B2 might be act as a positive regulator in maternal artery remodeling via both trophoblast invasion and endovascular formation.

Vascular Endothelial Growth Factor-A (VEGF-A) Mediates Activin A-Induced Human Trophoblast Endothelial-Like Tube Formation.

Remodeling of maternal spiral arteries during pregnancy requires a subpopulation of extravillous cytotrophoblasts (EVTs) to differentiate into endovascular EVTs. Activin A, which is abundantly expressed at the maternal-fetal interface, has been shown to promote trophoblast invasion, but its role in endovascular differentiation remains unknown. Vascular endothelial growth factor-A (VEGF-A) is well recognized as a key regulator in trophoblast endovascular differentiation. Whether and how activin A might regulate VEGF-A production in human trophoblasts and its relationship to endovascular differentiation have yet to be determined. In the present study, we found that activin A increased VEGF-A production in primary and immortalized (HTR8/SVneo) human EVT cells. In addition, activin A enhanced HTR8/SVneo endothelial-like tube formation, and these effects were attenuated by pretreatment with small interfering RNA targeting VEGF-A or the VEGF receptor 1/2 inhibitor SU4312. Pretreatment with the activin/TGF-β type 1 receptor (ALK4/5/7) inhibitor SB431542 abolished the stimulatory effects of activin A on phosphorylated mothers against decapentaplegic (SMAD)-2/3 phosphorylation, VEGF-A production, and endothelial-like tube formation. Moreover, small interfering RNA-mediated down-regulation of SMAD2, SMAD3, or common SMAD4 abolished the effects of activin A on VEGF-A production and endothelial-like tube formation. In conclusion, activin A may promote human trophoblast cell endothelial-like tube formation by up-regulating VEGF-A production in an SMAD2/3-SMAD4-dependent manner. These findings provide insight into the cellular and molecular events regulated by activin A during human implantation.

The role of the maternal immune system in the regulation of human birthweight.

Human birthweight is subject to stabilizing selection. Large babies are at risk of obstetric complications such as obstructed labour, which endangers both mother and child. Small babies are also at risk with reduced survival. Fetal growth requires remodelling of maternal spiral arteries to provide an adequate maternal blood supply to the placenta. This arterial transformation is achieved by placental trophoblast cells, which invade into the uterine wall. Under-invasion is associated with fetal growth restriction; but if invasion is excessive large babies can result. A growing body of evidence suggests that this process is controlled by interactions between killer-cell immunoglobulin-like receptors (KIRs) expressed on maternal uterine natural killer cells (uNK) and their corresponding human leukocyte antigen-C (HLA-C) ligands on invading trophoblast. Mothers with the KIR AA genotype and a fetus with a paternal HLA-C2 allele tend to have small babies, because this combination inhibits cytokine secretion by uNK. Mothers with the activating KIR2DS1 gene and an HLA-C2 fetus are more likely to have large babies. When KIR2DS1 binds to HLA-C2 this increases secretion of cytokines that enhance trophoblast invasion. We conclude that specific combinations of the highly polymorphic gene systems, KIR and HLA-C, contribute to successful reproduction by maintaining birthweight between two extremes.

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Objectives Human cytomegalovirus (HCMV) infection of the placenta is associated with significant pathological consequences, including pregnancy loss, intrauterine growth restriction, preeclampsia and preterm labor. It is thought that some of these pathological anomalies are attributed to the inability of extravillous cytotrophoblasts (EVT) to adequately invade the maternal uterine wall during first trimester pregnancy resulting in impaired remodeling of maternal spiral arteries. Our earlier studies show that HCMV inhibits cytotrophoblast invasion, although the mechanism(s) involved are not fully understood. We hypothesize that HCMV inhibits activity of histone deacetylase 6 (HDAC6) that is involved in the balanced control of deacetylation/acetylation of alpha-tubulin and cortactin that is essential for invadosome formation and function. The purpose of this study is to determine whether HCMV inhibits invasion of EVT through dysregulation of HDAC6-dependent invadosome formation and function. Methods An organotypic, 3-dimensional (3-D) model system using primary first trimester trophoblast progenitor cells (TBPCs) or the SGHPL-4 cell line was used to induce differentiation of cytotrophoblasts into an invasive phenotype. Invasive cytotrophoblasts were plated on fluorescein-labeled gelatin and analyzed for invadosome formation and function by confocal microscopy. Cells were infected with HCMV or treated with HDAC6-specific inhibitors to determine the ability of both to abrogate EVT invasion and to increase levels of acetylated alpha-tubulin, a cytoplasmic substrate of HDAC6, the latter of which has been shown, in cancer cells, to be required for invadosome formation and function. Results Cytotrophoblasts cultured in 3-D form actin-rich invasive protrusions that degrade extracellular matrix. HDAC6-specific inhibition and HCMV infection inhibit cytotrophoblast invasion and increase levels of acetylated alpha-tubulin. Conclusions These data suggest that HCMV impairs trophoblast invadosome formation and function through dysregulation of HDAC6. Elucidating the mechanism(s) by which HCMV impairs placentation may be key to understanding and inhibiting fetal and maternal pathologies, such as preeclampsia. Disclosures K.F. Swan: None. M. Ferris: None. G. Pridjian: None. D.E. Sullivan: None. C.A. Morris: None.

Editorial: New therapeutic targets for human placental angiogenesis disease.

Editorial: New therapeutic targets for human placental angiogenesis disease.

Uterine natural killer cells: their modulation by carbon monoxide and their impact on the remodeling of spiral arteries (MUC7P.768)

Abstract Pre-eclampsia (PE) and intrauterine growth restriction (IUGR) are linked to impaired remodeling of maternal spiral arteries (SA). We previously introduced Heme Oxygenase-1 (HO-1) as a positive modulator of pregnancy. Its main mediator, carbon monoxide, could mimic HO-1 protective effects in a mouse model of Hmox1 genetic deficiency. Here, we investigated whether HO-1 deficiency is related to gestational hypertension and if CO is able to prevent PE and IUGR through the modulation of uterine NK cells (uNK) that are necessary for initiation of SA remodeling. Hmox1+/- or Hmox1-/- implantations presented fewer uNK cell numbers and lower expression of uNK-related angiogeneic factors than Hmox1+/+ sites. Quantitative histology revealed that Hmox1+/- and Hmox1-/- implantations had shallow SA development. This was accompanied by IUGR and gestational hypertension. Application of CO at low dose during early to mid-gestation prevented IUGR in Hmox1+/- mothers, being this associated with enhanced in situ proliferation of uNKs and normalization of angiogenic parameters. Most importantly, CO improved SA remodeling and normalized blood pressure, ensuring a proper fetal growth. Thus, CO emerges as a key molecular player in pregnancy success by modulating uNKs, which results in promotion of SA remodeling, adequate fetal support/growth and prevention of gestational hypertension.

Carbon Monoxide Promotes Proliferation of Uterine Natural Killer Cells and Remodeling of Spiral Arteries in Pregnant Hypertensive Heme Oxygenase-1 Mutant Mice

Heme Oxygenase-1 (HO-1) and its metabolite carbon monoxide (CO) promote implantation and placentation. Pregnancy disorders such as preeclampsia and intrauterine growth restriction are linked to both HO-1 diminution and impaired remodeling of maternal spiral arteries (SAs). Here, we investigated whether CO is able to prevent preeclampsia and intrauterine growth restriction through the modulation of uterine natural killer (uNK) cells that are necessary for initiation of SA remodeling. Hmox1(+/-) or Hmox1(-/-) implantations presented fewer uNK cell numbers and lower expression of uNK-related angiogeneic factors compared with Hmox1(+/+) sites. Quantitative histology revealed that Hmox1(+/-) and Hmox1(-/-) implantations had shallow SA development that was accompanied by intrauterine growth restriction and gestational hypertension. Application of CO at low dose during early to midgestation prevented intrauterine growth restriction in Hmox1(+/-) mothers, this being associated with enhanced in situ proliferation of uNK cells and normalization of angiogenic parameters. Most importantly, CO improved SA remodeling and normalized blood pressure, ensuring a proper fetal growth. Thus, CO emerges as a key molecular player in pregnancy success by modulating uNK cells, which results in promotion of SA remodeling, adequate fetal support/growth, and prevention of hypertension.