Platsenta geeniekspressiooni ning raseduse kulgu mõjutavad ühenukleotiidsed variandid

Väitekirja elektrooniline versioon ei sisalda publikatsioonePlatsenta on unikaalne organ, mis eksisteerib inimkehas ainult raseduse ajal ning kõrvalekalded selle normaalsest arengust ja funktsioonist võivad kaasa tuua rasedustüsistusi, näiteks preeklampsia. Nende üks riskitegureid on nihe oluliste platsenta geenide avaldumise profiilis. Mehhanismid, mis vastutavad platsenta genoomi regulatsiooni eest vastavalt loote vajadustele ja raseduse etapile pole seni detailselt teada. Muude regulaatorite seas on esile tõusnud ka geneetiliste variantide ehk eVariantide mõju geenide avaldumise taseme mõjutajatena. Platsenta koes on neid seni vähe uuritud. Antud töö eesmärk oli uurida platsenta genoomi variantide mõju geenide avaldumisele ning rasedustüsistuste tekke riskile. Esiteks analüüsin kahe preeklampsia kandidaatgeeni Vaskulaarse endoteeli kasvufaktori retseptor 1 (FLT1) ja Stanniokaltsiin 1 (STC1) varieeruvust. Eesti rasedate valimis (2097 naist) tuvastasin FLT1 geeni lähedal asuva variandi tugeva ning spetsiifilise seose preeklampsia esinemise riskiga. On huvitav, et see variant mõjutas FLT1 geeni avaldumise taset ainult preeklampsia juhtumite platsentades. Leidsin ka STC1 geeniprodukti taset mõjutava geenivariandi, kuid selle seos preeklampsiaga vajab veel täiendavaid uuringuid. Teiseks viisin läbi ülegenoomse analüüsi, et uurida laiemalt platsenta kude mõjutavaid eVariante. Tuvastasin 199 geneetilist seost, mis mõjutasid 63 geeni avaldumist. Neist 13 olid varasemalt platsentas kirjeldamata. Illustreerides platsenta geneetiliste variantide laia fenotüübilist mõju, oli osa leitud geenivariante varasemalt seostatud täiskasvanuea haiguste riskidega või olid minu analüüsitud valimis seotud vastsündinu kasvuparameetritega. Kombineerides tulemusi varasema kirjandusega, koostasin koondnimekirja ~400 platsenta geenist, mille avaldumine on mõjutatud geneetilisest varieeruvusest. See ülevaade on hea lähtepunkt tulevastele platsenta eVariantide uurimustele nii bioloogilises kui meditsiinilises võtmes, e.g., seoses rasedustüsistusetega.The placenta is a unique transient organ only present during the pregnancy. Deviations from normal placental development can lead to pregnancy complications such as preeclampsia. One of the risk factors for complications is a disruption of important placental gene expression profiles. Mechanisms that regulate the placental genes to provide accurate and dynamic expression in response to fetal needs and pregnancy stage are still not fully understood. Genetic variants modulating gene expression or eVariants are among many possible mechanisms. Still, placental eVariants are underexplored. This thesis project aimed to investigate the effect of placental variants on gene expression and the risk of developing a pregnancy complication. First, the variation near two preeclampsia candidate genes, Vascular endothelial growth factor receptor 1 (FLT1) and stanniocalcin-1 (STC1) were analyzed. I detected a specific association between preeclampsia risk and a FLT1 variant in a sizeable Estonian cohort (2097 pregnant women). Interestingly, the preeclampsia risk variant affected FLT1 gene expression only in the preeclampsia placentas. Another variant near STC1 was shown to affect the gene expression, but its link to preeclampsia risk needs further research. Secondly, I conducted a genome-wide analysis to identify placental eVariants broadly. Overall, I uncovered 199 links that affected the expression of 63 genes, 13 of which were previously unknown for the placenta. Illustrating the broad impact of placental genetic variants, some eVariants were previously associated with adult diseases or pointed to an association with newborn parameters in the analyzed sample set. Combining the results with previous studies, I compiled a list of over 400 robust placental genes affected by genetic variation. This overview is a good starting point for future placenta eVariant research both in biological and medical aspects, e.g., regarding pregnancy complications.https://www.ester.ee/record=b545014

Stanniocalcin-1 Hormone in Nonpreeclamptic and Preeclamptic Pregnancy : Clinical, Life-Style, and Genetic Modulators

Context and Objectives: The study represents the first comprehensive analysis of Stanniocalcin-1 (STC1) hormone in human pregnancy, assessing clinical, lifestyle, and genetic determinants of circulating STC1 at term. Design, Setting, and Participants: Participants included women with (n = 50) and without (n = 316) preeclampsia (PE) at delivery, recruited in the REPROgrammed fetal and/or maternal METAbolism (REPROMETA) study (2006-2011, Estonia). Genetic association analysis combined PE cases (n = 597) and controls (n = 623) from the REPROMETA and Finnish Genetics of Preeclampsia Consortium (2008-2011) studies. Main Outcome Measure(s): Maternal postpartum plasma STC1 was measured by ELISA (n = 366) and placental STC1 gene expression by TaqMan quantitative RT-PCR (n = 120). Genotyping was performed using Sequenom MassArray. Results: Significantly higher STC1 plasma level was measured for the PE (median, 1952 pg/mL; 1030-4284 pg/mL) compared with non-PE group (median, 1562 pg/mL; 423-3781 pg/mL; P = 3.7 = 10 = 4, Mann-Whitney U test). Statistical significance was enhanced after adjustment for cofactors (linear regression, P = 1.8 x 10(-6)). STC1 measurements were negatively correlated with maternal smoking. Prepregnancy body mass index had a positive correlation with STC1 only among PE patients (r = 0.45; P =.001). The strongest genetic association with hormone concentrations was detected for STC1 single nucleotide polymorphisms rs3758089 (C allele: minor allele frequency, 5%; linear regression: beta = 249.2 pg/mL; P =.014) and rs12678447 (G allele: minor allele frequency, 7%; beta = 147.0 pg/mL; P =.082). rs12678447 placental genotypes were significantly associated with STC1 gene expression (P =.014). The REPROMETA/Finnish Genetics of Preeclampsia Consortium metaanalysis suggested an increased risk to develop late-onset PE for the rs12678447 G allele carriers (P =.05; odds ratio = 1.38 [0.98 -1.93]). Conclusions: Increased STC1 hormone represents a hallmark of late-onset PE. STC1 gene variants modulate placental gene expression and maternal hormone levels.Peer reviewe

Extensive shift in placental transcriptome profile in preeclampsia and placental origin of adverse pregnancy outcomes

One in five pregnant women suffer from gestational complications, prevalently driven by placental malfunction. Using RNASeq, we analyzed differential placental gene expression in cases of normal gestation, late-onset preeclampsia (LO-PE), gestational diabetes (GD) and pregnancies ending with the birth of small-for-gestational-age (SGA) or large-for-gestational-age (LGA) newborns (n = 8/group). In all groups, the highest expression was detected for small noncoding RNAs and genes specifically implicated in placental function and hormonal regulation. The transcriptome of LO-PE placentas was clearly distinct, showing statistically significant (after FDR) expressional disturbances for hundreds of genes. Taqman RT-qPCR validation of 45 genes in an extended sample (n = 24/group) provided concordant results. A limited number of transcription factors including LRF, SP1 and AP2 were identified as possible drivers of these changes. Notable differences were detected in differential expression signatures of LO-PE subtypes defined by the presence or absence of intrauterine growth restriction (IUGR). LO-PE with IUGR showed higher correlation with SGA and LO-PE without IUGR with LGA placentas. Whereas changes in placental transcriptome in SGA, LGA and GD cases were less prominent, the overall profiles of expressional disturbances overlapped among pregnancy complications providing support to shared placental responses. The dataset represent a rich catalogue for potential biomarkers and therapeutic targets.Peer reviewe

Novel Early Pregnancy Multimarker Screening Test for Preeclampsia Risk Prediction

Preeclampsia (PE) is a common pregnancy-linked disease, causing preterm births, complicated deliveries, and health consequences for mothers and offspring. We have previously developed 6PLEX, a multiplex assay that measures PE-related maternal serum biomarkers ADAM12, sENG, leptin, PlGF, sFlt-1, and PTX3 in a single test tube. This study investigated the potential of 6PLEX to develop novel PE prediction models for early pregnancy. We analyzed 132 serum samples drawn at 70–275 gestational days (g days) from 53 pregnant women (PE, n = 22; controls, n = 31). PE prediction models were developed using a machine learning strategy based on the stepwise selection of the most significant models and incorporating parameters with optimal resampling. Alternative models included also placental FLT1 rs4769613 T/C genotypes, a high-confidence risk factor for PE. The best performing PE prediction model using samples collected at 70–98 g days comprised of PTX3, sFlt-1, and ADAM12, the subject's parity and gestational age at sampling (AUC 0.94 [95%CI 0.84–0.99]). All cases, that developed PE several months later (onset 257.4 ± 15.2 g days), were correctly identified. The model's specificity was 80% [95%CI 65–100] and the overall accuracy was 88% [95%CI 73–95]. Incorporating additionally the placental FLT1 rs4769613 T/C genotype data increased the prediction accuracy to 93.5% [AUC = 0.97 (95%CI 0.89–1.00)]. However, 6PLEX measurements of samples collected at 100–182 g days were insufficiently informative to develop reliable PE prediction models for mid-pregnancy (accuracy <75%). In summary, the developed model opens new horizons for first-trimester PE screening, combining the easily standardizable 6PLEX assay with routinely collected antenatal care data and resulting in high sensitivity and specificity

STC1 polümorfismide seos riskiga preeklampsia tekkeks

2018-06-0

Changes in Children's Answers to Open Questions about the Earth and Gravity

Many studies that have been conducted to describe children's knowledge about the Earth and gravity have produced discrepant results. However, as most of these studies have been cross-sectional and they have used different methods for collecting and analyzing data, the question Do children at some point construct internally consistent but incorrect explanations to elementary astronomical phenomena? has not been fully answered. The aim of the study was to further explore this question by examining how children respond to open questions about the Earth and gravity and how these answers change over time. Schoolchildren's (=159) answers were examined four times with one-year intervals. It was found that directly after learning the topics in school many children gave synthetic responses and some oscillated between correct and incorrect explanations for a time. By the fourth grade more than half of the children were able to give scientifically accurate answers and good knowledge of facts supported children's ability to correctly generalize their existing knowledge. It was also shown that most children do not construct consistent nonscientific models of the Earth and that only thorough understanding of the discussed phenomena will lead to consistent answering