Project description:Reprogramming to pluripotency after overexpression of OCT4, SOX2, KLF4 and MYC is accompanied by global genomic and epigenomic changes. Histone modification and DNA methylation states in iPSCs have been shown to be highly similar with embryonic stem cells (ESCs). However, epigenetic differences still exist between iPSCs and ESCs. In particular, aberrant DNA methylation states found in iPSCs are a major concern for using iPSCs in a clinical setting. Thus, it is critical to find factors that regulate DNA methylation states in reprogramming. Here, we found that the miR-29 family is an important epigenetic regulator during human somatic cell reprogramming. Our global DNA methylation and hydroxymethylation analysis shows that DNA demethylation is a major event mediated by miR-29a depletion during early reprogramming, and that iPSCs derived from miR-29a depletion are epigenetically closer to ESCs. Our findings uncover an important miRNA-based approach to generate clinically robust iPSCs.
Project description:Reprogramming to pluripotency after overexpression of OCT4, SOX2, KLF4 and MYC is accompanied by global genomic and epigenomic changes. Histone modification and DNA methylation states in iPSCs have been shown to be highly similar with embryonic stem cells (ESCs). However, epigenetic differences still exist between iPSCs and ESCs. In particular, aberrant DNA methylation states found in iPSCs are a major concern for using iPSCs in a clinical setting. Thus, it is critical to find factors that regulate DNA methylation states in reprogramming. Here, we found that the miR-29 family is an important epigenetic regulator during human somatic cell reprogramming. Our global DNA methylation and hydroxymethylation analysis shows that DNA demethylation is a major event mediated by miR-29a depletion during early reprogramming, and that iPSCs derived from miR-29a depletion are epigenetically closer to ESCs. Our findings uncover an important miRNA-based approach to generate clinically robust iPSCs.
Project description:Reprogramming to pluripotency after overexpression of OCT4, SOX2, KLF4 and MYC is accompanied by global genomic and epigenomic changes. Histone modification and DNA methylation states in iPSCs have been shown to be highly similar with embryonic stem cells (ESCs). However, epigenetic differences still exist between iPSCs and ESCs. In particular, aberrant DNA methylation states found in iPSCs are a major concern for using iPSCs in a clinical setting. Thus, it is critical to find factors that regulate DNA methylation states in reprogramming. Here, we found that the miR-29 family is an important epigenetic regulator during human somatic cell reprogramming. Our global DNA methylation and hydroxymethylation analysis shows that DNA demethylation is a major event mediated by miR-29a depletion during early reprogramming, and that iPSCs derived from miR-29a depletion are epigenetically closer to ESCs. Our findings uncover an important miRNA-based approach to generate clinically robust iPSCs.
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).
Project description:Methylome-wide DNA methylation profiling of whole blood samples in health children to find age-associated methylation sites. The Illumina Infinium 450k Human DNA methylation Beadchip v1.2 was used to obtain DNA methylation profiles across approximately 485,000 CpGs in 48 samples. Samples included 29 boys and 19girls.
Project description:Somatic cell reprogramming by transcription factors and other modifiers such as small molecules or miRNAs has opened broad avenues for the study of developmental processes, cell fate determination, and interplay of molecular mechanisms in signaling pathways. However, many of the mechanisms that drive nuclear reprogramming itself remain yet to be elucidated. Here, we analyzed the role of miR-29 during reprogramming in more detail. Therefore, we evaluated miR-29 expression during reprogramming of fibroblasts transduced with lentiviral OKS and OKSM vectors and we show that addition of c-MYC to the reprogramming factor cocktail decreases miR-29 expression levels. Moreover, we found that transfection of pre-miR-29a strongly decreased OKS-induced formation of GFP+- colonies in MEF-cells from Oct4-eGFP reporter mouse, whereas anti-miR-29a showed the opposite effect. Furthermore, we studied two pathways which are important for reprogramming and which involve miR-29 targets: active DNA-demethylation and Wntsignaling. We show that inhibition of active DNA-demethylation as well as activation of Wnt-signaling leads to decreased reprogramming efficiency. Moreover, transfection of premiR-29 resulted in elevated expression of β-Catenin transcriptional target sFRP2 and increased TCF/LEF-reporter activity. Finally, we report that Gsk3-β is a direct target of miR-29 in MEF-cells. Together, our findings contribute to the understanding of the molecular mechanisms by which miR29 influences reprogramming.
Project description:Genome wide DNA methylation profiling of cervical cancer samples and normal tissue. The Illumina Infinium 450K Human DNA methylation Beadchip v1.2 was used to obtain DNA methylation profiles across approximately 450,000 CpGs in cervical cancer samples. Samples included 102 cervical cancer samples and 29 histologicall normal samples.