Project description:Illumina Infinium 450k Human DNA Methylation BeadChip was used to obtain DNA methylation profiles across approximately 470,000 CpG and 2,700 non-CG loci in 195 DNA extracts from iPSCs, ESCs and donor cell lines. Non-CG methylation is an unexplored epigenetic hallmark of pluripotent stem cells. Here we report that a reduction in non-CG methylation is associated with impaired differentiation capacity into endodermal lineages. Genome-wide analysis of 2,670 non-CG sites in a discovery cohort of 25 phenotyped human induced pluripotent stem cell (hiPSC) lines revealed unidirectional loss (Δβ = 13%, p<7.4x10-4) of non-CG methylation that correctly identifies endodermal differentiation capacity in 23 out of 25 (92%) hiPSC lines. Translation into a simplified assay of only 9 non-CG sites maintains predictive power in the discovery cohort (Δβ = 23%, p<9.1x10-6) and correctly identifies endodermal differentiation capacity in nince out of ten pluripotent stem cell lines in an independent replication cohort consisting of hiPSCs reprogrammed from different cell types and different delivery systems, as well as human embryonic stem cell (hESC) lines. This finding infers non-CG methylation at these sites as a biomarker when assessing endodermal differentiation capacity as a readout.
Project description:Metabolism is vital to cellular function and tissue homeostasis during human lung development. In utero, embryonic pluripotent stem cells undergo endodermal differentiation towards a lung progenitor cell fate that can be mimicked in vitro using induced human pluripotent stem cells (hiPSCs) to study genetic mutations. To identify differences between wild type and surfactant protein B (SFTPB)-deficient cell lines during endoderm specification towards lung, we used an untargeted metabolomics approach to evaluate the developmental changes in metabolites. We found that the metabolites most enriched during the differentiation from pluripotent stem cell to lung progenitor cell, regardless of cell line, were sphingomyelins and phosphatidylcholines, two important lipid classes in fetal lung development. The SFTPB mutation had no metabolic impact on early endodermal lung development. The identified metabolite signatures during lung progenitor cell differentiation may be utilized as biomarkers for normal embryonic lung development.
Project description:Quality control of induced pluripotent stem cells remains a challenge. For validation of the pluripotent state, it is crucial to determine trilineage differentiation potential toward endoderm, mesoderm, and ectoderm. Here, we report GermLayerTracker, a combination of site-specific DNA methylation (DNAm) assays that serve as biomarker for early germ layer specification. CG dinucleotides (CpGs) were identified with characteristic DNAm at pluripotent state and after differentiation into endoderm, mesoderm, and ectoderm. Based on this, a pluripotency score was derived that may be indicative for differentiation capacity, as well as lineage-specific differentiation scores to monitor either directed differentiation, or self-organized multilineage differentiation in embryoid bodies. Furthermore, we established pyrosequencing assays for fast and cost-effective analysis. In the future, the GermLayerTracker could be used for quality control of pluripotent cells and to estimate lineage-specific commitment during initial differentiation events.
Project description:Quality control of induced pluripotent stem cells remains a challenge. For validation of the pluripotent state, it is crucial to determine trilineage differentiation potential toward endoderm, mesoderm, and ectoderm. Here, we report GermLayerTracker, a combination of site-specific DNA methylation (DNAm) assays that serve as biomarker for early germ layer specification. CG dinucleotides (CpGs) were identified with characteristic DNAm at pluripotent state and after differentiation into endoderm, mesoderm, and ectoderm. Based on this, a pluripotency score was derived that may be indicative for differentiation capacity, as well as lineage-specific differentiation scores to monitor either directed differentiation, or self-organized multilineage differentiation in embryoid bodies. Furthermore, we established pyrosequencing assays for fast and cost-effective analysis. In the future, the GermLayerTracker could be used for quality control of pluripotent cells and to estimate lineage-specific commitment during initial differentiation events.
Project description:DNA methylation plays an important role in development and disease. The primary sites of DNA methylation in vertebrates are cytosines in the CpG dinucleotide context, which account for roughly three quarters of the total DNA methylation content in human and mouse cells. While the genomic distribution, inter-individual stability and functional role of CpG methylation are reasonably well understood, little is known about DNA methylation targeting CpA, CpC and CpT dinucleotides. Here we report a comprehensive analysis of non-CG methylation in 72 genome-scale DNA methylation maps across human pluripotent and differentiated cell types. We confirm non-CG methylation to be predominant in pluripotent cell types and observe an expected decrease upon differentiation and near complete absence in various differentiated cells. Our data highlight that non-CG methylation is highly variable and shows little conservation between different pluripotent cell lines. While we show a strong correlation of non-CG methylation and DNMT3 expression levels we find a statistical independence of non-CG methylation from pluripotency associated gene expression. Finally, non-CG methylation appears to be spatially correlated with CpG methylation. In summary these results contribute further to our understanding of DNA methylation in human cells and help clarify previous observations using a large representative sample set. Examination of nonCG DNA methylation patterns in pluripotent and differentiated cells
Project description:DNA methylation plays an important role in development and disease. The primary sites of DNA methylation in vertebrates are cytosines in the CpG dinucleotide context, which account for roughly three quarters of the total DNA methylation content in human and mouse cells. While the genomic distribution, inter-individual stability and functional role of CpG methylation are reasonably well understood, little is known about DNA methylation targeting CpA, CpC and CpT dinucleotides. Here we report a comprehensive analysis of non-CG methylation in 72 genome-scale DNA methylation maps across human pluripotent and differentiated cell types. We confirm non-CG methylation to be predominant in pluripotent cell types and observe an expected decrease upon differentiation and near complete absence in various differentiated cells. Our data highlight that non-CG methylation is highly variable and shows little conservation between different pluripotent cell lines. While we show a strong correlation of non-CG methylation and DNMT3 expression levels we find a statistical independence of non-CG methylation from pluripotency associated gene expression. Finally, non-CG methylation appears to be spatially correlated with CpG methylation. In summary these results contribute further to our understanding of DNA methylation in human cells and help clarify previous observations using a large representative sample set.
Project description:Immunodeficiency, Centromeric Instability, and Facial Anomalies Type I (ICF1) Syndrome is a rare genetic disease caused by mutations in DNMT3B, a de novo DNA methyltransferase. However, the molecular basis of how DNMT3B-deficiency leads to ICF1 pathogenesis is unclear. Induced pluripotent stem cell (iPSC) technology facilitates the study of early human developmental diseases via facile in vitro paradigms. Here, we generate iPSCs from ICF Type 1 Syndrome patient fibroblasts followed by directed differentiation of ICF1-iPSCs to mesenchymal stem cells (MSCs). By performing genome-scale bisulfite sequencing, we find that DNMT3B-deficient iPSCs exhibit global loss of non-CG methylation and select CG hypomethylation at gene promoters and enhancers. Further unbiased scanning of ICF1 iPSC methylomes also identifies large megabase regions of CG hypomethylation typically localized in centromeric and subtelomeric regions. RNA sequencing of ICF1 and control iPSCs reveals abnormal gene expression in ICF1 iPSCs relevant to ICF Syndrome phenotypes, some directly associated with promoter or enhancer hypomethylation. Upon differentiation of ICF1 iPSCs to mesenchymal stem cells (MSCs), we find virtually all CG hypomethylated regions remained hypomethylated when compared to either wild-type iPSC-derived MSCs or primary bone-marrow MSCs. Collectively, our results show specific methylome and transcriptome defects in both ICF1-iPSCs and differentiated somatic cell lineages, providing a valuable stem cell system for further in vitro study of the molecular pathogenesis of ICF1 Syndrome. MethylC-seq and RNA-Seq in ICF Syndrome patient fibroblast derived induced pluripotent stem cells.
Project description:The variation among induced pluripotent stem cells (iPSCs) in their differentiation capacity to specific lineages is frequently attributed to somatic memory. In this study, we compared hematopoietic differentiation capacity of 35 human iPSC lines derived from four different tissues and four embryonic stem cell lines. The analysis revealed that hematopoietic commitment capacity (PSCs to hematopoietic precursors) is correlated with the expression level of the IGF2 gene independent of the iPSC origins. In contrast, maturation capacity (hematopoietic precursors to mature blood) is affected by iPSC origin; blood-derived iPSCs showed the highest capacity. However, some fibroblast-derived iPSCs showed higher capacity than blood-derived clones. Tracking of DNA methylation changes during reprogramming reveals that maturation capacity is highly associated with aberrant DNA methylation acquired during reprogramming, rather than the types of iPSC origins. These data demonstrated that variations in the hematopoietic differentiation capacity of iPSCs are not attributable to somatic memories of their origins. Undifferentiated human induced pluripotent stem cells (N = 23)
Project description:The variation among induced pluripotent stem cells (iPSCs) in their differentiation capacity to specific lineages is frequently attributed to somatic memory. In this study, we compared hematopoietic differentiation capacity of 35 human iPSC lines derived from four different tissues and four embryonic stem cell lines. The analysis revealed that hematopoietic commitment capacity (PSCs to hematopoietic precursors) is correlated with the expression level of the IGF2 gene independent of the iPSC origins. In contrast, maturation capacity (hematopoietic precursors to mature blood) is affected by iPSC origin; blood-derived iPSCs showed the highest capacity. However, some fibroblast-derived iPSCs showed higher capacity than blood-derived clones. Tracking of DNA methylation changes during reprogramming reveals that maturation capacity is highly associated with aberrant DNA methylation acquired during reprogramming, rather than the types of iPSC origins. These data demonstrated that variations in the hematopoietic differentiation capacity of iPSCs are not attributable to somatic memories of their origins. human pluripotent stem cell-derived hematopoietic precursor cells (n = 33)
Project description:The variation among induced pluripotent stem cells (iPSCs) in their differentiation capacity to specific lineages is frequently attributed to somatic memory. In this study, we compared hematopoietic differentiation capacity of 35 human iPSC lines derived from four different tissues and four embryonic stem cell lines. The analysis revealed that hematopoietic commitment capacity (PSCs to hematopoietic precursors) is correlated with the expression level of the IGF2 gene independent of the iPSC origins. In contrast, maturation capacity (hematopoietic precursors to mature blood) is affected by iPSC origin; blood-derived iPSCs showed the highest capacity. However, some fibroblast-derived iPSCs showed higher capacity than blood-derived clones. Tracking of DNA methylation changes during reprogramming reveals that maturation capacity is highly associated with aberrant DNA methylation acquired during reprogramming, rather than the types of iPSC origins. These data demonstrated that variations in the hematopoietic differentiation capacity of iPSCs are not attributable to somatic memories of their origins. Bisulfite converted genomic DNA lysates from induced pluripotent stem cellã??and embryonic stem cell lines were hybridized to Illumina HumanMethylation450 BeadChip.