Project description:Genome wide DNA methylation profiling of MZ twins discordant and concordant for BMI. The Illumina Infinium 450k Human DNA methylation Beadchip was used to obtain DNA methylation profiles across approximately 485,000 CpGs. Samples included 30 MZ twin pairs discordant for BMI and 10 pairs concordant for BMI.
Project description:This is the first high-throughput analysis of DNA methylation in autoimmune diseases. We have used a cohort of MZ twins discordant for three diseases whose clinical signs often overlap: systemic lupus erythematosus (SLE), rheumatoid arthritis and dermatomyositis. Only MZ twins discordant for SLE featured widespread changes in the DNA methylation status of a significant number of genes. Individual analysis confirmed the existence of DNA methylation and expression changes in genes relevant to SLE pathogenesis. Our findings not only identify potentially relevant DNA methylation markers for the clinical characterization of SLE patients but also support the notion that epigenetic changes may be critical in the clinical manifestations of autoimmune disease. Total DNA isolated by standard procedures from 59 White Blood Cell (WBC) samples corresponding to monozygotic twins discordant for three different autoimmune diseases: systemic lupus erythematosus (SLE), rheumatoid arthritis (RA) and dermatomyositis (DM) and two additional controls for each MZ twin pair.
Project description:This is the first high-throughput analysis of DNA methylation in autoimmune diseases. We have used a cohort of MZ twins discordant for three diseases whose clinical signs often overlap: systemic lupus erythematosus (SLE), rheumatoid arthritis and dermatomyositis. Only MZ twins discordant for SLE featured widespread changes in the DNA methylation status of a significant number of genes. Individual analysis confirmed the existence of DNA methylation and expression changes in genes relevant to SLE pathogenesis. Our findings not only identify potentially relevant DNA methylation markers for the clinical characterization of SLE patients but also support the notion that epigenetic changes may be critical in the clinical manifestations of autoimmune disease.
Project description:Genome wide DNA methylation profiling of adipose tissue of MZ twins discordant and concordant for BMI. The Illumina Infinium 450k Human DNA methylation Beadchip was used to obtain DNA methylation profiles across approximately 485,000 CpGs. Samples included 24 pairs discordant and 11 pairs concordant for BMI.
Project description:Immunoglobulin A nephropathy (IgAN) is the most common primary glomerulonephritis involves both genetic and environmental factors. DNA methylation, the most studied epigenetic modification, was shown to play a role in IgAN. In two pairs of IgAN-discordant monozygotic (MZ) twins, here we assessed genome-wide DNA methylation profiling and gene expression profiling in order to characterize DNA methylation changes in IgAN and their potential influences on gene expression.
Project description:Background: Low birth weight is associated with an increased adult metabolic disease risk. It is widely discussed that poor intrauterine conditions could induce long-lasting epigenetic modifications, leading to systemic changes in regulation of metabolic genes. In a unique cohort of 17 monozygotic (MZ) monochorionic female twins very discordant for birth weight (relative differences ranging from 21.3-35.7%), we examined if adverse prenatal growth conditions experienced by the smaller co-twins lead to systemic long-lasting DNA methylation changes. Genome-wide DNA methylation profiles were acquired from saliva DNA using the Infinium HumanMethylation450 BeadChip, targeting ~2% of all CpGs in the genome. Results: Overall, co-twins showed very similar genome-wide DNA methylation profiles. Since observed differences were almost exclusively caused by variable cellular composition, an original marker-based adjustment strategy was developed to eliminate such variation at affected CpGs. Among adjusted and unchanged CpGs 3153 were differentially methylated between the heavy and light co-twins at nominal significance (p<0.01), of which 45 showed absolute mean β-value differences >0.05 (max=0.08). Deep bisulfite sequencing of eight such loci revealed that differences remained in the range of technical variation, arguing against a reproducible biological effect. Analysis of methylation in repetitive elements using methylation-dependent primer extension assays also indicated no significant intra-pair differences. Conclusions: Severe intrauterine growth differences observed within these MZ twins are not associated with long-lasting DNA methylation differences in cells composing saliva, detectable with up-to-date technologies. Additionally, our results indicate that uneven cell type composition can lead to spurious results and should be addressed in epigenomic studies. DNA methylation profiles of saliva from 17 Adult Female MZ MC Twins discordant for birth weight.
Project description:Objective: Systemic lupus erythematosus (SLE) has limited monozygotic (MZ) twin concordance, implying a role for other pathogenic factors than genetic variation, such as epigenetic changes. Using the disease discordant twin model, we investigated genome-wide DNA methylation changes in sorted CD4+ T-cells, monocytes, granulocytes and B-cells in twin pairs with at least one SLE-affected twin. Methods: Peripheral blood from 15 SLE twin pairs (six MZ, nine dizygotic (DZ)) was processed using gradient density centrifugation for the granulocyte fraction. CD4+ T-cells, monocytes and B-cells were further isolated using magnetic beads. Genome-wide DNA methylation was analysed using Infinium HumanMethylation450K BeadChips. Probes with a p-value <0.01 between SLE twins and co-twins were considered statistically significant and a median DNA methylation difference >7% biologically relevant. Findings were validated using pyrosequencing and replicated in an independent case-control sample. Results: In paired analyses of discordant SLE twins restricted to the gene promoter and start region, we identified 55, 327, 247 and 1628 genes with differentially methylated CpGs in CD4+ T-cells, monocytes, granulocytes and B-cells, respectively. All cell types displayed marked hypomethylation in interferon-regulated genes, such as IFI44L, PARP9 and IFITM1, which was more pronounced in twins with flare within the past two years. In contrast to the other cell types, differentially methylated CpGs in B-cells were predominantly hypermethylated, where the most important upstream regulators included TNF and EP300. Conclusion: Hypomethylation of interferon-regulated genes occurs in all major cellular compartments in SLE twins. The observed B-cell promoter hypermethylation is a novel finding with potential significance for SLE pathogenesis.
Project description:The methylation profiles of bisulfite-modified DNA of CD19+ cells from MZ twins discordant for CVID were compared using the Infinium HumanMethylation450 BeadChips (Illumina, Inc., San Diego, CA,). This platform allows the interrogation of >485,000 methylation sites per sample at single-nucleotide resolution, and comprises an average of 17 CpG sites per gene in the 99% of RefSeq genes. 96% of CpG islands are covered, with additional coverage in CpG island shores and the regions flanking them. The samples were hybridized in the array following the manufacturer’s instructions. Total DNA isolated by standard procedures from CD19+ cells (total B lymphocytes) corresponding to two monozygotic twins discordant for common variable immunodeficiency.
Project description:In this study, we used Illumina Infinium HumanMethylation450 Beadchips to compare DNA methylation profiles in blood from 10 pairs of MZ twins and 8 individuals recruited at 0, 3, 6, and 9 months. MZ Group (Group A) contained 10 pairs of MZ twins ranging from 23 to 74 years old, including 8 female and 12 male subjects.Longitudinal study group (Group B) included a pair of MZ (male) twins and 6 unrelated individuals (3 male, 3 female), aged from 24 to 39. Except subject H, all participants in Longitudinal study group (Group B) were recalled every 3 months for 9 months (0, 3, 6, and 9 m). Subject H was studied only at 0, 6, and 9 months. Bisulphite converted DNA from the 60 samples were hybridised to the Illumina Infinium 450k Human Methylation Beadchip