Project description:Background: Preeclampsia, traditionally characterized by high blood pressure and proteinuria, is a common pregnancy complication, which affects 2-8% of all pregnancies. Although children born to women with preeclampsia have a higher risk of hypertension in later life, the mechanism of this increased risk is unknown. DNA methylation is an epigenetic modification that has been studied as a mediator of cellular memory of adverse exposures in utero. Since each cell type in the body has a unique DNA profile, cell subtype composition is a major confounding factor in studies of tissues with heterogeneous cell types. The best way to avoid this confounding effect is by using purified cell types. However, the use purified cell types in large cohort translational studies is difficult. The amnion, the inner layer of the fetal membranes of placenta, is derived from the epiblast and consists of two cell types, which are easy to isolate from the delivered placenta. In this study, we demonstrate the value of using amnion samples for DNA methylation studies, revealing distinctive patterns between fetuses exposed to preeclampsia or hypertension and fetuses from normal pregnancies. Results: We performed a genome-wide DNA methylation analysis, HELP-tagging, on 62 amnion samples from placentas of uncomplicated, normal pregnancies, and those with complications of preeclampsia or hypertension. Using a regression model approach, we found 123, 85 and 99 loci with high confidence hypertension-associated, proteinuria-associated and hypertension and proteinuria-associated DNA methylation changes, respectively. We also found that these differentially methylated regions overlap loci previously reported as differentially methylated regions in preeclampsia. Conclusions: Our findings support prior observations that preeclampsia is associated with changes of DNA methylation near genes that have previously been found to be dysregulated in preeclampsia. We propose that amnionic membranes represent a valuable surrogate fetal tissue on which to perform epigenome-wide association studies of adverse intrauterine conditions.

Project description:Preeclampsia (PE), which affects 4-8% of human pregnancies, causes significant maternal and neonatal morbidity and mortality. Within the basal plate, placental cytotrophoblasts (CTBs) of fetal origin invade the uterus and extensively remodel the maternal vasculature. In PE, CTB invasion is often shallow, and vascular remodeling is rudimentary. To better understand possible causes, we conducted a global analysis of gene expression at the maternal-fetal interface in placental samples from women with PE (n = 12; 24-36 wk) vs. samples from women who delivered due to preterm labor with no evidence of infection (n = 11; 24-36 wk), a condition that our previous work showed is associated with normal CTB invasion. Using the HG-U133A&B Affymetrix GeneChip platform, and statistical significance set at log odds-ratio of B >0, 55 genes were differentially expressed in PE. They encoded proteins previously associated with PE [e.g. Flt-1 (vascular endothelial growth factor receptor-1), leptin, CRH, and inhibin] and novel molecules [e.g. sialic acid binding Ig-like lectin 6 (Siglec-6), a potential leptin receptor, and pappalysin-2 (PAPP-A2), a protease that cleaves IGF-binding proteins]. We used quantitative PCR to validate the expression patterns of a subset of the genes. At the protein level, we confirmed PE-related changes in the expression of Siglec-6 and PAPP-A2, which localized to invasive CTBs and syncytiotrophoblasts. Notably, Siglec-6 placental expression is uniquely human, as is spontaneous PE. The functional significance of these novel observations may provide new insights into the pathogenesis of PE, and assaying the circulating levels of these proteins could have clinical utility for predicting and/or diagnosing PE. Keywords: disease state analysis Basal plate biopsies of preterm labor (24-36 weeks; n=11) and preterm severe preeclampsia (24-36 weeeks; n=12) were isolated and the global gene expression profiles determined using Affymetrix Human GeneChips. Comparisons between the preeclampsia samples and the preterm labor controls revealed genes differentially expressed in preeclampsia.

Project description:Background: Preeclampsia (PE) is a placental disease characterized by hypertension and proteinuria in pregnant women, which is associated with a high maternal and infantile morbidity. However, circulating biomarkers able to predict the prognosis of PE are lacking. Methods: Thirty-eight women were included in the study. They consisted of 19 patients with PE (13 with severe PE and 6 women with non-severe PE) and 19 gestational age-matched normal pregnancy controls. We measured coagulation pathway, endothelial responses and microparticle release and circulating gene expression in PE patient groups and normotensive controls. Results: The measurement of markers associated with coagulation pathway, endothelial activation and circulating microparticles enabled to discriminate PE from normal pregnancy but were not sufficient to distinguish severe from non-severe PE. PE patients also exhibited a specific transcriptional program distinct from that of control women and subtle differences were observed between severe and non-severe PE. Functional annotation of the up-modulated signature in PE highlighted two main functions related to ribosome and complement. Importantly, we found that 8 genes were specifically up-modulated in severe preeclampsia. Among these genes, the expression of VSIG4 was significantly increased in patients with severe preeclampsia in comparison with controls and patients with non-severe preeclampsia. Conclusion: Using transcriptional signatures of blood samples, we identified the gene encoding the estrogen receptor as a potential diagnostic marker of severe preeclampsia. In addition, the determination of this gene may improve the prognostic assessment of severe preeclampsia. Thirty-eight women were included in the study: 19 patients with PE, including 6 women with non-severe PE and 13 with severe PE, and 19 women with normal pregnancy (NP) selected according to age, weight, smoking status, race, gestational age at the inclusion, and blood pH (Table 1 of manuscript). Women with NP had no history of medical illness or medication, and received routing prenatal care. The diagnostic of PE was based on a blood pressure of M-bM-^IM-% 140/90 mmHg taken twice, uricemia above normal laboratory range (120-420 M-BM-5mol/L), and proteinuria higher than 300 mg in a 24 hour-collection, occurring after 20 gestational weeks in previously normotensive women (Table 2). The criteria used to define severe PE included one of the following conditions: a blood pressure higher than 160/110 mmHg, a proteinuria higher than 1500 mg/24h), a multisystem disorder, maternal cerebral symptoms (seizures, stroke) or intrauterine growth restriction below the 3M-BM-0 percentile. Women with multiple gestations, fetal congenital malformations/chromosomal abnormalities, recent infection, antiphospholipid antibodies, trauma, drug or alcohol abuse during pregnancy, preexisting hypertension, thrombophilia with PE history, or women receiving anticoagulant or antiaggregation therapy were excluded from the study. Two microarrays (one non-severe PE and one normal) were discarded from the analysis for technical reasons. Thus, only 36 microarrays are included here.

Project description:Purpose: Next generation bulk RNA sequencing of a large group (37 individuals) of matched tissues (fetal brain and fetal placenta) from human fetuses collected via elective termination at 72-82 days post conception (d.p.c.), a timeframe that closely matches the embryonic developmental window used in our mouse studies (14.5-16.5) Methods: Human placenta (maternal decidua separated from fetal placenta) and fetal brain tissues were obtained from the NIH-supported Laboratory of Developmental Biology at the University of Washington between the years 1999 and 2010 and used under a protocol approved by the Duke University Institutional Review Board (Pro00014066). Tissue specimens were stored at -80°C until required for RNA or protein extraction. Prior to collection, informed consent was obtained from all individuals undergoing the elective termination. RNA from human tissue was prepared for sequencing using an Illumina TrueSeq RNA Exome kit and sequenced on an Illumina NovaSeq 6000 configured for a S2 flow cell at 50bp PE. Results: PCR for the Y chromosome (SRY) identified 17 male and 20 female fetal tissue sets, with the average age of 78.2 d.p.c. for both sexes. No maternal data were available, so we assessed decidual triglyceride accumulation to use as a proxy for maternal weight, given that women with overweight/obesity exhibit triglyceride accumulation in the placenta. Triglyceride levels trended higher in pregnancies with female fetuses, but there was no significant difference between triglyceride accumulation in decidua associated with male or female pregnancies. Pearson's Correlation of gene expression with maternal triglyceride accumulation from bulk RNA-seq from 16 matched male and 19 matched female brain and placenta samples revealed a strong dimorphic trend in gene expression. In male pregnancies, differentially correlated genes were predominantly over-expressed with increasing maternal weight (i.e. gene expression increased as maternal triglycerides increased); the opposite effect was seen in female pregnancies. In the male brain, only 45 genes significantly correlated with maternal triglyceride accumulation (either positive or negative), whereas 781 genes were significantly correlated in females.

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Dysregulation of the circulating and tissue-based renin-angiotensin system in preeclampsia

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