Project description:Genome wide DNA methylation profiling of normal and trisomic placentas, and maternal blood cell DNA. The aim of this study was to search for methylation differences between maternal and fetal(placenta) cell free DNA, and between normal and trisomic placentas for an optimized methylation based noninvasive prenatal diagnosis of fetal chromosomal aberations. The Illumina Infinium 450k Human DNA methylation Beadchip was used to obtain DNA methylation profiles across approximately 450,000 CpGs in DNA samples from Chorionic villus samples(CVS) and DNA samples from whole blood. Samples included 12 Maternal blood cell samples from normal pregnancies, 12 normal CVS, 12 Trisomy 21 CVS, 12 trisomy 18 CVS and 6 trisomy 13 CVS samples. Bisulphite converted DNA from the 54 samples were hybridized to the Illumina Infinium 450k Human Methylation Beadchip.
Project description:Comparative analysis of DNA methylation in 12 human chorionic villus samples and 12 human maternal blood cell samples We performed a genome wide analysis of DNA methylation first trimester CVS samples and gestational age matched MBCs. We analyzed DNA samples obtained from 12 CVS samples and 12 MBC samples. Data were generated using two high-throughput approaches: the Infinium “humanmethylation27” platform marketed by Illumina and a custom Agilent-based platform. We then compared these data with genome wide transcription data for the same tissues. This Series covers only the Illumina HumanMethylation27 part of the study.
Project description:Genome wide DNA methylation profiling of normal and trisomic placentas, and maternal blood cell DNA. The aim of this study was to search for methylation differences between maternal and fetal(placenta) cell free DNA, and between normal and trisomic placentas for an optimized methylation based noninvasive prenatal diagnosis of fetal chromosomal aberations. The Illumina Infinium 450k Human DNA methylation Beadchip was used to obtain DNA methylation profiles across approximately 450,000 CpGs in DNA samples from Chorionic villus samples(CVS) and DNA samples from whole blood. Samples included 12 Maternal blood cell samples from normal pregnancies, 12 normal CVS, 12 Trisomy 21 CVS, 12 trisomy 18 CVS and 6 trisomy 13 CVS samples.
Project description:Noninvasive prenatal diagnosis currently used does not achieve desirable levels of sensitivity and specificity. Recently, fetal methylated DNA biomarkers in maternal whole blood have been explored for noninvasive prenatal detection. However, such efforts cover only chromosomal aneuploidy; fetal methylated DNA biomarkers for detecting single-gene disease remain to be discovered. To address this issue, we systematically screened significantly hypermethylated genes in fetal tissues compared with maternal blood for noninvasive prenatal diagnosis of various inherited diseases. First, Methylated-CpG island recovery assay combined with CpG island array was performed in four maternal peripheral bloods and their corresponding placental tissues. Subsequently, direct bisulfite sequencing and combined bisulfite restriction analysis (COBRA) were carried out to validate the reliability of methylation microarray analysis. As results, 310 significantly hypermethylated genes in fetal tissues were detected by microarray. Two of five randomly selected hypermethylated genes detected by microarray were confirmed to be hypermethylated in fetal tissue samples by direct bisulfite sequencing. All four randomly selected hypermethylated genes detected by microarray were confirmed to be hypermethylated in five independent amniotic fluid samples and five independent chorionic villus samples from 10 pregnant women by CORBA. In conclusions, We found a lot of hypermethylated genes and methylation sites in fetal tissues, some of which have great potential to be developed into molecular markers for noninvasive prenatal diagnosis of monogenic disorders. Further clinical study is warranted to confirm these findings. Paired experiments, placental tissues vs. maternal peripheral bloods. Biological replicates: 4 placental tissues and 4 correspoding maternal peripheral bloods.
Project description:We present a detailed structural and functional analysis of the placental epigenome at its maternal interface. Specifically, we analyzed the DNA methylation pattern of chromsomes 13, 18, and 21 in samples of chorionic villus (CVS) and maternal blood cells (MBC) using custom designed microarrays. We then compared these data with transcription data for the same tissues. In addition to the discovery that CVS genomes are significantly more hypomethylated than their MBC counterparts, we identified numerous tissue-specific differentially methylated regions (T-DMRs). We further discovered that these T-DMRs are clustered spatially along the genome and are enriched for genes with tissue-specific biological functions. We identified unique patterns of DNA methylation associated with distinct genomic structures such as gene bodies, promoters and CpG islands and identified both direct and inverse relationships between DNA methylation levels and gene expression levels in gene bodies and promoters respectively. Furthermore, we found that these relationships were significantly associated with CpG content. We conclude that the early gestational placental DNA methylome is highly organized and is significantly associated with transcription. These data provide a unique insight into the structural and regulatory characteristics of the placental epigenome at its maternal interface and will drive future analyses of the role of placental dysfunction in gestational disease.
Project description:We present a detailed structural and functional analysis of the placental epigenome at its maternal interface. Specifically, we analyzed the DNA methylation pattern of chromsomes 13, 18, and 21 in samples of chorionic villus (CVS) and maternal blood cells (MBC) using custom designed microarrays. We then compared these data with transcription data for the same tissues. In addition to the discovery that CVS genomes are significantly more hypomethylated than their MBC counterparts, we identified numerous tissue-specific differentially methylated regions (T-DMRs). We further discovered that these T-DMRs are clustered spatially along the genome and are enriched for genes with tissue-specific biological functions. We identified unique patterns of DNA methylation associated with distinct genomic structures such as gene bodies, promoters and CpG islands and identified both direct and inverse relationships between DNA methylation levels and gene expression levels in gene bodies and promoters respectively. Furthermore, we found that these relationships were significantly associated with CpG content. We conclude that the early gestational placental DNA methylome is highly organized and is significantly associated with transcription. These data provide a unique insight into the structural and regulatory characteristics of the placental epigenome at its maternal interface and will drive future analyses of the role of placental dysfunction in gestational disease. Two-condition experiment, CVS vs. MBC cells. Biological replicates: 2 pooled CVS samples, 2 pooled MBC samples, collected from different patients. Each sample is divided into two parts, one part treated with HpaII enzyme, one part without. The two parts then are hybridized to the two channels of the same array. Two arrays for each sample, with dye swap to remove dye bias.
Project description:Noninvasive prenatal diagnosis currently used does not achieve desirable levels of sensitivity and specificity. Recently, fetal methylated DNA biomarkers in maternal whole blood have been explored for noninvasive prenatal detection. However, such efforts cover only chromosomal aneuploidy; fetal methylated DNA biomarkers for detecting single-gene disease remain to be discovered. To address this issue, we systematically screened significantly hypermethylated genes in fetal tissues compared with maternal blood for noninvasive prenatal diagnosis of various inherited diseases. First, Methylated-CpG island recovery assay combined with CpG island array was performed in four maternal peripheral bloods and their corresponding placental tissues. Subsequently, direct bisulfite sequencing and combined bisulfite restriction analysis (COBRA) were carried out to validate the reliability of methylation microarray analysis. As results, 310 significantly hypermethylated genes in fetal tissues were detected by microarray. Two of five randomly selected hypermethylated genes detected by microarray were confirmed to be hypermethylated in fetal tissue samples by direct bisulfite sequencing. All four randomly selected hypermethylated genes detected by microarray were confirmed to be hypermethylated in five independent amniotic fluid samples and five independent chorionic villus samples from 10 pregnant women by CORBA. In conclusions, We found a lot of hypermethylated genes and methylation sites in fetal tissues, some of which have great potential to be developed into molecular markers for noninvasive prenatal diagnosis of monogenic disorders. Further clinical study is warranted to confirm these findings.
Project description:The maternal and paternal copies of the genome are both required for mammalian development and this is primarily due to imprinted genes, those that are mono-allelically expressed based on parent-of-origin. Typically, this pattern of expression is regulated by differentially methylated regions (DMRs) that are established in the germline and maintained after fertilisation. There are a large number of germline DMRs that have not yet been associated with imprinting and their function in development is unknown. In this study, we developed a genome-wide approach to identify novel imprinted DMRs, specifically in the human placenta, and investigated the dynamics of imprinted DMRs during development in somatic and extra-embryonic tissues. DNA methylation was evaluated using the Illumina HumanMethylation450 array in 116 human tissue samples, publically available reduced representation bisulfite sequencing in the human embryo and germ cells, and targeted bisulfite sequencing in term placentas. 43 known and 101 novel imprinted DMRs were identified in the human placenta, by comparing methylation between diandric and digynic triploids and female and male gametes. 72 novel DMRs showed a pattern consistent with placental-specific imprinting and this mono-allelic methylation was entirely maternal in origin. Strikingly, these DMRs exhibited polymorphic imprinted methylation specifically in placenta. These data suggest that imprinting in human development is far more extensive and dynamic than previously reported and that the placenta preferentially maintains maternal germline-derived DNA methylation For the identification of imprinted DMRs in the placenta, chorionic villous samples from 5 diandric and 5 digynic triploids pregnancies were assayed, along with a pooled sample of complete hydatiform moles (CHM). Placental chorionic villous samples (n=63) included 29 control pregnancies delivered at term, while the remaining 34 were delivered preterm or miscarried, or had abnormal MSS results, IUGR or LOPET. The preterm births were associated with one or more of: preterm labour, premature rupture of membranes (PROM), chorioamnionitis, placental abruption, and incompetent cervix. All samples were determined to be chromosomally normal using standard karyotyping or comparative genome hybridization, as previously described (Robinson et al. 2010). Two to four independent sites were taken from each placenta and after DNA extraction from chorionic villous, the DNA was pooled before being utilized in this study. Thirty-three fetal tissues, including brain (n=8), spinal cord (n=7), muscle (n=9), and kidney (n=9) were collected from second trimester foetuses, as previously described (Price et al. 2012). Adult female whole blood samples (n=10) were collected from control women. Extra-embryonic cell types (n=19), including cord blood (embryonic), cord, amniotic membrane, chorionic membrane, 1st, 2nd and 3rd trimester trophoblast and mesenchyme, and decidua (maternal), were isolated from control placental samples.