Project description:Over the last 20-80 million years the mammalian placenta has taken on a variety of morphologies through both divergent and convergent evolution. Recently we have shown that the human placenta genome has a unique epigenetic pattern of large partially methylated domains (PMDs) and highly methylation domains (HMDs) with gene body DNA methylation positively correlating with level of gene expression. In order to determine the evolutionary conservation of DNA methylation patterns and transcriptional regulatory programs in the placenta, we performed a genome-wide methylome (MethylC-seq) analysis of human, rhesus macaque, squirrel monkey, mouse, dog, horse, and cow placentas as well as opossum extraembryonic membrane. We found that, similar to human placenta, mammalian placentas and opossum extraembryonic membrane have globally lower levels of methylation compared to somatic tissues. However, not all species have clear PMD/HMDs in their placentas. Instead what is conserved is higher methylation over the bodies of genes involved in mitosis, vesicle-mediated transport, protein phosphorylation, and chromatin modification compared with the rest of the genome. As in human placenta, high gene body methylation is associated with higher gene expression across species. Analysis of DNA methylation in mouse and cow oocytes shows the same pattern of gene body methylation over many of the same genes as in the placenta, suggesting that this conserved pattern of active gene body methylation of the placenta may be established very early in development. MethylC-seq on placentas of 7 mammals, trophoblasts of rhesus, brains of 3 mammals, oocytes of cow, and human cordblood
Project description:Over the last 20-80 million years the mammalian placenta has taken on a variety of morphologies through both divergent and convergent evolution. Recently we have shown that the human placenta genome has a unique epigenetic pattern of large partially methylated domains (PMDs) and highly methylation domains (HMDs) with gene body DNA methylation positively correlating with level of gene expression. In order to determine the evolutionary conservation of DNA methylation patterns and transcriptional regulatory programs in the placenta, we performed a genome-wide methylome (MethylC-seq) analysis of human, rhesus macaque, squirrel monkey, mouse, dog, horse, and cow placentas as well as opossum extraembryonic membrane. We found that, similar to human placenta, mammalian placentas and opossum extraembryonic membrane have globally lower levels of methylation compared to somatic tissues. However, not all species have clear PMD/HMDs in their placentas. Instead what is conserved is higher methylation over the bodies of genes involved in mitosis, vesicle-mediated transport, protein phosphorylation, and chromatin modification compared with the rest of the genome. As in human placenta, high gene body methylation is associated with higher gene expression across species. Analysis of DNA methylation in mouse and cow oocytes shows the same pattern of gene body methylation over many of the same genes as in the placenta, suggesting that this conserved pattern of active gene body methylation of the placenta may be established very early in development.
Project description:We investigated the DNA methylation and gene expression of 20 chorionic villi samples from early onset preeclampsia placentas to 20 gestational age matched controls. From this we were able to see a widespread disregulation in DNA methylation across a subset of genes in the genome. This may help to elucidate the underlying biological problems that lead to early onset preeclampsia. We noted that there were DNA methylation changes in many genes of importance as well as in different genomic elements such as enhancers. Bisulfite converted DNA from 20 third trimester early onset preeclampsia placentas and 20 gestational age matched controls
Project description:Genome-wide DNA methylation profiling of placentas from diandric and digynic triploidies. DNA methylation profiles across more than 27,000 CpGs were obtained by using the Illumina Infinium 27k Human DNA methylation Beadchip v1.2. Placentas of 10 diandric and 10 digynic triploidies were included.
Project description:We investigated the DNA methylation and gene expression of 20 chorionic villi samples from early onset preeclampsia placentas to 20 gestational age matched controls. From this we were able to see a widespread disregulation in DNA methylation across a subset of genes in the genome. This may help to elucidate the underlying biological problems that lead to early onset preeclampsia. We noted that there were DNA methylation changes in many genes of importance as well as in different genomic elements such as enhancers.
Project description:Preeclampsia is one of the leading causes of maternal death worldwide. While the root cause is still unknown, the underlying biology of the disorder is becoming more clear. We recently published a study showing large, significant differences in DNA methylation in 3rd trimester placental samples associated with early-onset preeclampsia (EOPET) compared to controls. In this study, to identify DNA methylation differences associated with preeclampsia that occur early in pregnancy and to further delineate common EOPET-associated differences, we utilized a genetic defect, trisomy 16 (T16), that is predisposing to preeclampsia. We ran T16 placental samples from the 1st trimester (n=5) and 3rd trimester (n=10) against gestational age matched controls on the Illumina Infinium HumanMethylation450 BeadChip. Third trimester samples were from pregnancies with T16 confined to the placenta (confined placental mosaicism 16;CPM16), and consisted of samples that were and were not associated with EOPET (n=5 each). We identified a large number of DNA methylation differences in CPM16 samples compared to controls using stringent criteria (n=2254;False Discovery Rate <0.01, ->0.15). Several of these differences (11%) overlapped differences observed in chromosomally normal EOPET using similarly stringent criteria (FDR<0.01;->0.125). Isolating EOPET-associated probes produced a similar - distribution amongst CPM16 samples, although samples associated with EOPET showed a tendency towards larger DNA methylation differences. We also identified 262 DNA methylation differences between 1st trimester T16 and 1st trimester controls. Of these, 77 overlapped differences seen in 3rd trimester CPM16. Investigating these 77 T16/CPM16 specific DNA methylation differences, we identified three probes near two genes (ARGHEF37 and JUNB) that were also present as EOPET-associated methylation differences. In summary, we identified significant overlapping DNA methylation profiles of placentas with T16 and chromosomally normal placentas associated with EOPET. Specific DNA methylation marks within these profiles may be of future clinical utility in early identification of pregnancies susceptible to EOPET. Bisulfite converted DNA from 5 1st trimester trisomy 16 placentas, 5 chromosomally normal 1st trimester placentas, 10 third trimester placentas from confined placental mosaicism placentas and 10 chromosomally normal 3rd trimester placentas
Project description:Genome-wide DNA methylation profiling of placentas from diandric and digynic triploidies. DNA methylation profiles across more than 27,000 CpGs were obtained by using the Illumina Infinium 27k Human DNA methylation Beadchip v1.2. Placentas of 10 diandric and 10 digynic triploidies were included. Bisulfite converted DNA from the 20 samples were hybridized to the Illumina Infinium 27k Human Methylation Beadchip v1.2
Project description:Fetal growth in utero is affected by both inherent genetic programming in combination with environmental factors, such as maternal health and nutrition. Epidemiologic data in growth-altered fetuses, either growth-restricted (IUGR) or large for gestational age (LGA), demonstrate compelling evidence that these fetuses are at increased risk for cardiovascular and metabolic disease in adulthood. In this study, we used RRBS to examine genome wide DNA methylation variation in placental samples from offspring born IUGR, LGA, and appropriate for gestational age (AGA). We identified almost 200 differentially methylated genes among these groups. Among these genes, the differentially methylated regions were disproportionately located in transcription-regulatory regions such as promoters. Our results suggest that the gene expression and methylation state of the human placenta are related and sensitive to the intrauterine environment. We profiled DNA methylation for 17 human placentas, in which 5 were from LGA, 6 from IUGR and 6 from AGA placentas as controls
Project description:Transfer of frozen-thawed embryos leads to sex-specific DNA hypermethylation in both human and mouse placentas. : In humans, frozen ET led to placentas with significant alterations in DNA methylation with most genes demonstrating hypermethylation compared to placentas from fresh ET (4402 CpGs; 1600 genes; p-value < 0.05 in two–tailed unpaired t tests, and a mean methylation difference > 0.05). When compared to control samples, both frozen and fresh samples showed significant differences in methylation.(Frozen vs Control: 5600 CpGs, 2775 genes; Fresh vs Control: 4096 CpGS; 1914 genes; p-value < 0.05, mean methylation difference > 0.05). Paired analysis showed similar trends, despite controlling for maternal environment. Sex specific analysis revealed that these changes were primarily driven by male placentas, as seen by a larger number of CpGs that were differentially methylated, and a larger proportion of genes with at least 2 differentially methylated CpG sites in male placentas as compared to female placentas. (Males: 15572 CpGs, 4399 genes; Females: 7441 CpGs, 3070 genes; p-value < 0.05, mean methylation difference > 0.05). In order to isolate the effects of vitrification we utilized the mouse model, controlling for the effect of the maternal hormonal milieu. In the first genome-wide profiling of DNA methylation in a mouse IVF model, we found that trends in DNA methylation differences paralleled those seen in human placentas. Using similar significance cutoffs as for human samples, and BumpHunter analysis that identifies differentially methylated regions to compensate for a lower number of samples, placentas derived from frozen embryos were predominantly hypermethylated compared to placentas after fresh ET (589 DMRs, 445 genes). Both frozen and fresh embryo transfer samples demonstrated perturbations compared to control samples (Frozen vs Control: 1787 DMRs, 1319 genes; Fresh vs Control: 1119 DMRs, 808 genes). Consistent with the sex-specific trends we observed in human placentas, differences between samples derived from frozen compared to fresh embryo transfer were driven by changes in male placentas (Males: 1069 DMRs, 798 genes; Females:14 DMRs, 11 genes) . When considering the effect of IVF as a whole, murine placentas were predominantly hypomethylated, replicating existing human genome-wide methylation data. As seen previously, IVF led to changes in placental weight, placental morphology and microvessel density in mice, but no persistent changes were seen after embryo vitrification alone. Sexually dimorphic epigenetic changes could indicate differential susceptibility of male and female embryos to IVF-associated perturbations. This observation highlights the importance of sex-specific evaluation of the incidence of adverse outcomes. Similarities between changes seen in mouse and human samples underscore the suitability of the mouse model in evaluating the effect of ART on the epigenetic landscape. This convergence is especially valuable, given limited access to human tissues and the ability to isolate specific interventions in the mouse model.
Project description:Background: The placenta is vital for fetal development and its contributions to various developmental issues, such as pregnancy complications, fetal growth restriction, and maternal exposure, have been extensively studied in mice. Contrary to popular belief, the placenta forms mainly from fetal tissue; therefore, it has the same biological sex as the fetus it supports. However, while placental function is linked to increased risks of pregnancy complications and neurodevelopmental diseases in male offspring in particular, the sex-specific epigenetic (e.g., DNA methylation) and transcriptomic features of the late-gestation mouse placenta remain largely unknown.Methods: We collected male and female mouse placentas at late gestation (E18.5, n = 3/sex) and performed next-generation sequencing to identify genome-wide sex-specific differences in transcription and DNA methylation. Results: Our sex-specific analysis revealed 358 differentially expressed genes (DEGs) on autosomes, which were associated with signaling pathways involved in transmembrane transport and the responses to viruses and external stimuli. X chromosome DEGs (n = 39) were associated with different pathways, including those regulating chromatin modification and small GTPase-mediated signal transduction. Sex-specific differentially methylated regions (DMRs) were more common on the X chromosomes (n = 3756) than on autosomes (n = 1705). Interestingly, while most X chromosome DMRs had higher DNA methylation levels in female placentas and tended to be included in CpG dinucleotide-rich regions, 73% of autosomal DMRs had higher methylation levels in male placentas and were distant from CpG-rich regions. Several sex-specific DEGs were correlated with sex-specific DMRs. A subset of the sex-specific DMRs present in late-stage placentas were already established in mid-gestation (E10.5) placentas, while others were acquired later in placental development.Conclusion: Our study provides comprehensive lists of sex-specific DEGs and DMRs that collectively cause profound differences in the DNA methylation and gene expression profiles of late-gestation mouse placentas. Our results demonstrate the importance of incorporating sex-specific analyses into epigenetic and transcription studies to enhance the accuracy and comprehensiveness of their conclusions and help address the significant knowledge gap regarding how sex differences influence placental function.