Genome-Wide Mapping of 5-mC and 5-hmC in severely Preeclamptic Placentas.
ABSTRACT: Preeclampsia (PE) is a major contributor of maternal mortality with uncertain etiology. Recent studies suggested that epigenetic modifications, including DNA methylation, play a vital role in the development of PE. In this study, we have mapped genome-wide distribution of 5-methylcytosin (5-mC) and 5-hydroxymethylcytosine (5-hmC) using MeDIP and (h)MeDIP in the placentas from severely preeclamptic patients and normal controls. A total 194485 pooled 5-mC peaks and 138133 pooled 5-hmC peaks were identified, of which 714 5-mC peaks and 119 5-hmC peaks showed significant difference between patients and controls (>2-fold, p<0.05).To our knowledge, this is the first report of DHMRs (Differentially Hydroxy-Methylated Regions) in preeclamptic placenta. We not only confirmed the aberrant DNA methylated regions in the process of preeclampsia reported previously, but also identified unreported regions. A total of 4 selected DMRs (Differentially Methylated Regions) were also confirmed by MassARRAY EppiTYPER. Of these, PTPRN2, which had low level of 5-mC and high level of 5-hmC at gene body, was further verified to have lower methylation level at promoter regions in case group compared with controls. In conclusion, our study provided genome-wide distribution of 5-mC and 5-hmC in severe PE and normal controls, which have further clinical value for the identification of diagnostic and therapeutic markers for severe PE. Examination of 5-mC and 5-hmC pattern in 4 control cases' tissue and 4 severely Preeclamptic Placentas cases' tissue.
Project description:5-Hydroxymethylcytosine (hmC) is particularly abundant in mammalian brains with yetto be revealed functions. Here, we present genome-wide and single-base-resolutionmaps of hmC and mC in the human brain. We demonstrated that hmCs increasemarkedly from the fetal to the adult stage, and in the adult brain, 13.4% of all CpGs arehighly hydroxymethylated with strong enrichment at genic regions and distal regulatoryelements. Notably, hmC peaks were identified at the 5' splicing sites at the exon-intronboundary, suggesting a mechanistic link between hmC and splicing. We also report asurprising transcription-correlated hmC bias toward the sense strand and an mC biastoward the antisense strand of gene bodies. Furthermore, hmC is negatively correlatedwith H3K27me3-marked repressive genomic regions, and is more enriched in poisedenhancers than active enhancers. Our results provide insights into understanding themultiple potential functions of hmC in the human brain. A cell type specific hydroxymethylome sample of NeuN+ neurons in frontal lobe from the same adult individual, whose TAB-Seq data was deposited in GSE46710
Project description:Preeclampsia (PE) is a pregnancy disorder characterized by high blood pressure and proteinuria that can cause adverse health effects in both mother and fetus. There is no current cure for PE other than delivery of the fetus. While the etiology is unknown, poor placentation of the placenta due to aberrant signaling of growth and angiogenic factors has been postulated as causal factors of PE. In addition, environmental contaminants, such as the metal cadmium (Cd), have been linked to placental toxicity and increased risk of developing PE. Here, we use a translational study design to investigate genomic and epigenomic alterations in both placentas and placental trophoblasts, focused on the angiogenesis-associated transforming growth factor-beta (TGF-β) pathway. Genes within the TGF-β pathway displayed increased expression in both the preeclamptic placenta and Cd-treated trophoblasts. In addition, miRNAs that target the TGF-β pathway were also significantly altered within the preeclamptic placenta and Cd-treated trophoblasts. Integrative analysis resulted in the identification of a subset of Cd-responsive miRNAs, including miR-26a and miR-155, common to preeclamptic placentas and Cd-treated trophoblasts. These miRNAs have previously been linked to PE and are predicted to regulate members of the TGF-β pathway. Results from this study provide future targets for PE treatment. Overall design: Placental Tissue Samples from 32 women (16 normotensive women, denoted with a P, and 16 preeclamptic women, denoted with a Q) were analyzed for differenital miRNA expression controling for age, race and gestational age JEG3 cells were exposed and not exposed to cadmium and were analyzed for differential miRNA expression JEG3 cell changes were compared to preelcampsia associated changes to determine overlaps
Project description:Though the pathophysiology of preeclampsia (PE) is unclear worldwide, placental hypoxia has been implicated in the pathologic processes of PE.In this study, we profiled the transcriptome in BeWo and JEG-3 cells cultured in hypoxic condition or normal ones based on the RNA sequencing dataset. After filtered the low-quality ones, the RNA readers was aligned to human genome hg19 by TopHat and then assembled by Cufflinks. The expression value of each transcript was calculated and consequently differentially expressed genes were screened out. CD39 and ZDHHC14 were found to have both different mRNA in hypoxic cells and abnormal methylation level in severely preeclamptic placentas. The mRNA expression of CD39 and ZDHHC14 in placental tissues were analyzed using qRT-PCR. The differential methylated regions (DMRs) of CD39 and ZDHHC14 were confirmed by MassARRY EppiTYPER. The effect of hypoxia on trophoblast cells was detected with western blotting and enzyme linked immunosorbent assay. The results showed CD39 and ZDHHC14were significantly lower in severe PE placenta, hypoxia significantly reduced the expression of CD39 and ZDHHC14 and the secretion of CD39 in trophoblast cells. Therefore, we believed hypoxia plays an important role in the processes of severe PE via decreasing the expression of CD39 and ZDHHC14 by changing their methylation level in placenta. Overall design: mRNA profiles of three cell lines at five stages and two different conditions were generated by deep sequencing, using HiSeq 2500.
Project description:We analyzed the genome-wide binding of Tet1 in control (shScr) and Tet1 knockdown (shTet1) mouse ES cells using two different Tet1 antibodies (Tet1-C and Tet1-N). Furthermore, we generated genome-wide mapping of hydroxymethyl cytosine (hmC) and methyl cytosine (mC). We find that hmC, in contrast to mC, is also found at transcription start sites (TSSs), and that there is a significant overlap between Tet1 binding and hmC positive regions. Surprisingly, our results also suggest, that Tet1 has a role in transcriptional repression. We showed that Tet1 associates with Sin3A co-repressor complex, and by performing ChIP-sequencing of Sin3A, we find co-localisation of Tet1 and Sin3a throughout the genome Overall design: Examination of Tet1 and Sin3A binding as well as hmC and mC localization in mouse ES cells
Project description:We analyzed the genome-wide binding of Tet1 in control (shScr) and Tet1 knockdown (shTet1) mouse ES cells using two different Tet1 antibodies (Tet1-C and Tet1-N). Furthermore, we generated genome-wide mapping of hydroxymethyl cytosine (hmC) and methyl cytosine (mC). We find that hmC, in contrast to mC, is also found at transcription start sites (TSSs), and that there is a significant overlap between Tet1 binding and hmC positive regions. Surprisingly, our results also suggest, that Tet1 has a role in transcriptional repression. We showed that Tet1 associates with Sin3A co-repressor complex, and by performing ChIP-sequencing of Sin3A, we find co-localisation of Tet1 and Sin3a throughout the genome Examination of Tet1 and Sin3A binding as well as hmC and mC localization in mouse ES cells
Project description:Normal pregnancy requires adaptations of the maternal vasculature. During preeclampsia these adjustments are not well established, resulting in maternal hypertension and proteinuria. The effects of preeclampsia on the maternal vasculature are not yet fully understood. We aimed to identify gene expression differences in the aorta between non pregnant, healthy pregnant, and experimental preeclamptic rats using a genome wide approach. Whole aortic tissue was isolated from rats with low-dose LPS-induced preeclampsia, healthy pregnant and non-pregnant rats. Gene expression was measured by a whole genome microarray. Overall design: 3 groups were compared. Preeclamptic animals (n=5), healthy pregnant animals (n=5), and non pregnant animals (n=4)
Project description:An important question for the use of the mouse as a model for studying human disease is the degree of functional conservation of genetic control pathways from human to mouse. The human placenta and mouse placenta show structural similarities but there has been no systematic attempt to assess their molecular similarities or differences. We built a comprehensive database of protein and microarray data for the highly vascular exchange region micro-dissected from the human and mouse placenta near-term. Abnormalities in this region are associated with two of the most common and serious complications of human pregnancy, maternal preeclampsia (PE) and fetal intrauterine growth restriction (IUGR), each disorder affecting ~5% of all pregnancies. To compare the gene expression patterns in the vascular exchange regions of the human (villus tree) and mouse (labyrinth) placenta. Experiment Overall Design: Mouse labyrinth tissue was micro-dissected form naturally mated crosses of C57Bl/6J mice. Placentas were individually dissected on embryonic day 17.5. From each litter ¼ of the tissue were set aside for RNA extraction and microarray analysis and ¾ for cellular fractionation and proteomic analysis, as recently described (Kislinger et al., 2006). Human villous trees were dissected from term normal placenta delivered by cesarean section from a term pregnancy (~ 38 weeks). Tissue was divided for organellar fractionation and RNA extraction.
Project description:Plasma from normal and preeclamptic pregnancies was collected and added in the culture medium of HUVEC cells. The aims are double: identifying putative biomarkers that could be modified recurrently in the endothelium under preeclampsia and understand at term the molecular bases of the increased risk of cardiovascular and kidney diseases in woman that have had a preeclampsia. 2 pools of 3 control plasmas and 2 pools of 4 preeclamptic plasma were organized and added at a concentration of 1/10 on HUVEC cells, during 24 hours before transcriptomic analysis
Project description:Preeclampsia (PE), a hypertensive disorder of pregnancy, is hypothesized to be associated with, if not mechanistically related to abnormal placental function. However, the exact mechanisms regulating the pathogenesis of PE remain unclear. While many studies have investigated changes in gene expression in the PE placenta, the role of epigenetics in PE associated placental dysfunction remains unclear. Using the genome-wide Illumina Infinium Methylation 450 BeadChip array, we analyzed gene-specific alterations in DNA methylation in placental biopsies collected from normal pregnant women delivering at term (n=14), with term PE (≥37 weeks; n=19) or with preterm PE (<37 weeks, n=12). Of the 485,582 gene loci on the array, compared to controls, 229 loci were differentially methylated in PE placentas and 3411 loci were differentially methylated in preterm PE (step up p-value <0.05 and >5% methylation difference). Functional annotation of the differentially methylated genes in preterm PE placentas revealed a 32 gene cluster in the cadherin and cell adhesion functional groups (Benjamini p<0.00001). Hypermethylation of CDH11 (p=0.0143), COL5A1 (p=0.0127) and TNF (p=0.0098) and hypomethylation of NCAM1 (p=0.0158) was associated with altered mRNA expression in preterm PE placentas. These studies demonstrate aberrant methylation, correlating with disease severity, in PE placentas. Bisulphite converted DNA from the 45 samples were hybridised to the Illumina Infinium 450k Human Methylation Beadchip v1.2
Project description:Enzymes catalyzing the methylation of the 5-position of cytosine (mC) have essential roles in regulating gene expression, genome stability, and maintaining cellular identity. Recently Tet1, which is highly expressed in embryonic stem (ES) cells, was found to oxidize the methyl group of mC converting it to 5-hydroxymethyl cytosine (hmC)3. Here, we present the genome-wide mapping of Tet1 and hmC in mouse ES cells. We show that Tet1 binds throughout the genome with the majority of binding sites located at transcription start sites (TSSs) and within genes. Similar to Tet1 and mC, also hmC is found throughout the genome and in particular in gene bodies. However, in contrast to mC, hmC is enriched at TSSs. Tet1 and hmC are associated with genes critical for the control of development and differentiation, which become methylated during differentiation. Surprisingly our results also suggest that Tet1 has a role in transcriptional repression. We show that Tet1 binds to a significant proportion of target genes that are positive for the Polycomb repressive histone mark H3K27me3, and that downregulation of Tet1 also leads to increased expression of a group of Tet1 target genes. In agreement with a potential repressive function, we show that Tet1 associates with the Sin3A co-repressor complex, which also co-localises with Tet1 throughout the genome. We propose that Tet1 fulfils dual functions in transcriptional regulation, where it fine-tunes DNA methylation and associates with the Sin3A co-repressor complex to prevent transcriptional activation. Overall design: [GSM611209-GSM611217] Control (shScr) or two different Tet1 knockdown (shTet1#4 or shTet1#5) mouse ES cells were used. Each experiment was performed in triplicates. [GSM675884-GSM675889] Control (shScr) or Sin3A knockdown (shSin3A) mouse ES cells were used.Each experiment was performed in triplicates.