Epigenome analysis of fetal and adult liver samples
Ontology highlight
ABSTRACT: Genome wide DNA methylation analysis of 96 adult and 14 fetal liver samples The study includes 110 individuals, 14 fetal and 96 adult samples, no replicates. Liver samples from 14 fetuses were obtained at gestational week 8-12. Adult liver samples were collected from 52 organ donors who had met accidental death and 44 liver samples from patients undergoing liver resection due to malignant tumors, most commonly from patients with metastatic colon cancers. Liver biopsies from these patients were collected from 'healthy' tissue that showed no visible pathological changes compared to the adjacent tumor.
Project description:Diploidy is a fundamental genetic feature in mammals, in which haploid cells normally arise only as post-meiotic germ cells that serve to insure a diploid genome upon fertilization. Gamete manipulation has yielded haploid embryonic stem (ES) cells from several mammalian species, but as of yet not from humans. Here we analyzed a large collection of human parthenogenetic ES cell lines originating from haploid oocytes, leading to the successful isolation and maintenance of human ES cell lines with a normal haploid karyotype. Haploid human ES cells exhibited typical pluripotent stem cell characteristics such as self-renewal capacity and a pluripotency-specific molecular signature. Although haploid human ES cells resembled their diploid counterparts, they also displayed distinct properties including differential regulation of X chromosome inactivation and genes involved in oxidative phosphorylation, alongside reduction in absolute gene expression levels and cell size. Intriguingly, we found that a haploid genome is compatible not only with the undifferentiated pluripotent state, but also with differentiated somatic fates representing all three embryonic germ layers, despite a persistent dosage imbalance between the autosomes and X chromosome. We expect that haploid human ES cells will provide novel means for studying human functional genomics, development and evolution. Genome-wide DNA methylation profiling by Illumina Infinium HumanMethylation 450K Beadchip was performed on a total of 12 samples, including undifferentiated haploid and diploid human parthenogenetic embryonic stem cells in either G1 or G2/M, as well as 3 in vitro fertilization (IVF) control embryonic stem cell lines.
Project description:Aging is a progressive process that results in the accumulation of intra- and extracellular alterations that in turn contribute to a reduction in health. Age-related changes in DNA methylation have been reported before and may be responsible for aging-induced changes in gene expression, although a causal relationship has yet to be shown. Using genome-wide assays, we analyzed age-induced changes in DNA methylation and their effect on gene expression with and without transient induction with the synthetic transcription modulating agent WY14,643. To demonstrate feasibility of the approach, we isolated peripheral blood mononucleated cells (PBMCs) from five young and five old healthy male volunteers and cultured them with or without WY14,643. Infinium 450K BeadChip and Affymetrix Human Gene 1.1 ST expression array analysis revealed significant differential methylation of at least 5 % (M-NM-^TYOM-bM-^@M-^I>M-bM-^@M-^I5 %) at 10,625 CpG sites between young and old subjects, but only a subset of the associated genes were also differentially expressed. Age-related differential methylation of previously reported epigenetic biomarkers of aging including ELOVL2, FHL2, PENK, and KLF14 was confirmed in our study, but these genes did not display an age-related change in gene expression in PBMCs. Bioinformatic analysis revealed that differentially methylated genes that lack an age-related expression change predominantly represent genes involved in carcinogenesis and developmental processes, and expression of most of these genes were silenced in PBMCs. No changes in DNA methylation were found in genes displaying transiently induced changes in gene expression. In conclusion, aging-induced differential methylation often targets developmental genes and occurs mostly without change in gene expression. Peripheral blood mononuclear cells were isolated from 10 volunteers (5 young 5 old), treated with the synthetic PPARalpha agonists WY14,643 or control for 13 hrs, and subjected to genome-wide DNA methylation and gene expression analysis. This entry contains the DNA methylation data.
Project description:Human pluripotent stem cells can be derived from somatic cells by forced expression of defined factors, and more recently by nuclear-transfer into human oocytes, revitalizing a debate on whether one reprogramming approach might be advantageous over the other. Here we compared the genetic and epigenetic stability of human nuclear-transfer embryonic stem cell (NT-ESC) lines and isogenic induced pluripotent stem cell (iPSC) lines, derived from the same somatic cell cultures of fetal, neonatal and adult origin. Both cell types shared similar genome-wide gene expression and DNA methylation profiles. Importantly, NT-ESCs and iPSCs have comparable numbers of de novo coding mutations but significantly higher than parthenogenetic ESCs. Similar to iPSCs NT-ESCs displayed clone- and gene-specific aberrations in DNA methylation and allele-specific expression of imprinted genes, similarly to iPSCs. The occurrence of these genetic and epigenetic defects in both NT-ESCs and iPSCs suggests that they are inherent to reprogramming, regardless of the underlying technique. Genome-wide DNA methylation profiling by Illumina Infinium HumanMethylation 450K Beadchip was performed on a total of 21 human cell lines, including: an isogenic set of 3 nuclear-transfer embryonic stem cell (NT-ESC) lines, 2 RNA-reprogrammed induced pluripotent stem cell (iPSC) lines and their parental neonatal fibroblast cell line; an isogenic set of 1 NT-ESC line, 6 iPSC lines and their parental adult fibroblast cell line (derived from a type 1 diabetic subject); as well as 7 control embryonic stem cell (ESC) lines.
Project description:Methylation profiling can reveal patterns of hypermethlation and hypomethylation associated with distinct biologic subtypes of acute lymphoblastic leukemia (ALL). We performed methylation profiling of Down syndrome ALL cases and controls to identify unique biologic features of this ALL subgroup. Ficoll-enriched, cryopreserved bone marrow aspirate samples were obtained from patients with B-precursor ALL at diagnosis and in remission
Project description:Determine methylation pattern in PDAC a genome-wide analysis was performed in a cohort of 167 PDAC and 29 adjacent pancreatic tissues samples using the Infinium 450k methylation arrays (Illumina). 167 pancreatic tumors (PDAC) x 29 adjacent -non tumor samples.
Project description:Many studies have compared the genetic and epigenetic profiles of human induced pluripotent stem cells (hiPSCs) to human embryonic stem cells (hESCs) and yet the picture remains unclear. To address this, we derived a population of neural precursor cells (NPCs) from the H1 (WA01) hESC line and generated isogenic iPSC lines by reprogramming. The gene expression and methylation profile of three lines were compared to the parental line and intermediate NPC population. We found no gene probe with expression that differed significantly between hESC and iPSC samples under undifferentiated or differentiated conditions. Analysis of the global methylation pattern also showed no significant difference between the two PSC populations. Both undifferentiated populations were distinctly different from the intermediate NPC population in both gene expression and methylation profiles. One point to note is that H1 is a male line and so extrapolation to female lines should be cautioned. However, these data confirm our previous findings that there are no significant differences between hESCs and hiPSCs at the gene expression or methylation level. 12 samples: 1 human NPC, 5 human ESC (UNDIFF), 6 human iPSC (UNDIFF)
Project description:In Gravesâ disease (GD), a combination of genetic, epigenetic and environmental factors causes an autoimmune response to the thyroid gland, characterized by lymphocytic infiltrations and autoantibodies targeting the thyroid stimulating hormone receptor (TSHR) and other thyroid antigens. To identify the epigenetic changes involved in GD, we performed a genome-wide analysis of DNA methylation and enrichment of H3K4me3 and H3K27ac histone marks in sorted CD4+ and CD8+ T cells. We found 365 and 3322 differentially methylated CpG sites in CD4+ and CD8+ T cells, respectively. Among the hypermethylated CpG sites, we specifically found enrichment of genes involved in T cell signaling (CD247, LCK, ZAP70, CD3D, CD3E, CD3G, CTLA4 and CD8A) and decreased expression of CD3 gene family members. The hypermethylation was accompanied with the active chromatin histone modifications as we found decreased signals of H3K4me3 and H3K27ac marks at several T cell signaling genes in ChIP-seq analysis. In addition, we found hypermethylation of the TSHR gene first intron, where several GD-associated polymorphisms are located. Our results demonstrate an involvement of dysregulated DNA methylation and histone modifications at T cell signaling genes in GD patients. Individuals were recruited from the Estonian Genome Center of the University of Tartu. Genomic DNA was extracted from sorted CD4+ (31 controls and 36 GD patients) and CD8+ (31 controls and 37 GD patients) T cells. The data collection was performed at the SNP&SEQ Technology Platform in Uppsala University, and data analysis was done at the Institute of Biomedicine and Translational Medicine in the University of Tartu.