Project description:Epigenetic processes such as DNA methylation play a key role in regulating tissue-specific and temporally-appropriate patterns of gene expression during development. Our knowledge about temporal changes to the epigenome in the developing human pancreas is limited. In this study we quantified levels of DNA methylation at over 800,000 sites in 112 human fetal pancreatic samples (51 male and 61 female) spanning from 6 to 21 post conception weeks (pcw). We found dramatic changes in DNA methylation across human pancreas development, with >22% of all methylation sites displaying significant changes across developmental age, with the majority of these sites showing stable levels of DNA methylation in the mature pancreas. Sites associated with developmental changes in DNA methylation during fetal pancreas development were significantly underrepresented in promoter regulatory regions but significantly overrepresented in regions flanking CpG islands (shores and shelves) and gene bodies. Highly significant differences in DNA methylation were observed between males and females at a number of autosomal sites, with a small number of regions showing sex-specific DNA methylation trajectories across pancreas development. Weighted gene correlation network analysis (WGCNA) revealed modules of co-methylated loci associated with developmental age were enriched for genes involved in maturity onset diabetes of the young (MODY) and other metabolic phenotypes. A comparison with developmentally-dynamic patterns of DNA methylation in the developing human brain revealed significant tissue specific differences between the fetal pancreas and the fetal brain. Our data confirms the prenatal period to be a time of dynamic epigenetic changes. To our knowledge, this is the most extensive study of DNA methylation patterns in human fetal pancreatic development.
Project description:Dynamic changes to the epigenome mediate key neurobiological and cognitive processes in the central nervous system, and also play a role in transcriptional regulation during brain development. Although the importance of DNA methylation in brain development is highlighted by the neurodevelopmental deficits associated with mutations in genes including methyl-CpG binding protein 2 (MECP2), our knowledge about the specific methylomic trajectories associated with human neurodevelopment is extremely limited. Here we report an analysis of genome-wide patterns of DNA methylation in 179 human fetal cortex samples. Bisulphite converted DNA from 179 human brain samples was hybridized to the Illumina 450K Human Methylation Beadchip.
Project description:Dynamic changes to the epigenome mediate key neurobiological and cognitive processes in the central nervous system, and also play a role in transcriptional regulation during brain development. Although the importance of DNA methylation in brain development is highlighted by the neurodevelopmental deficits associated with mutations in genes including methyl-CpG binding protein 2 (MECP2), our knowledge about the specific methylomic trajectories associated with human neurodevelopment is extremely limited. Here we report an analysis of genome-wide patterns of DNA methylation in 179 human fetal brain samples.
Project description:The progress made in directed differentiation of stem cells has shown that understanding human pancreas development can provide cues for generating unlimited amounts of insulin-producing beta cells for transplantation therapy in diabetes. However, current differentiation protocols have not been successful in reproducibly generating functional human beta cells in vitro, partly due to incomplete understanding of human pancreas development. Here, we present detailed transcriptomic analysis of the various cell types of the developing human pancreas, including their spatial gene patterns. We integrated single cell RNA sequencing with spatial transcriptomics at multiple developmental timepoints and revealed distinct temporal-spatial gene cascades in the developing human pancreas.
Project description:The progress made in directed differentiation of stem cells has shown that understanding human pancreas development can provide cues for generating unlimited amounts of insulin-producing beta cells for transplantation therapy in diabetes. However, current differentiation protocols have not been successful in reproducibly generating functional human beta cells in vitro, partly due to incomplete understanding of human pancreas development. Here, we present detailed transcriptomic analysis of the various cell types of the developing human pancreas, including their spatial gene patterns. We integrated single cell RNA sequencing with spatial transcriptomics at multiple developmental timepoints and revealed distinct temporal-spatial gene cascades in the developing human pancreas.
Project description:Pancreatic and duodenal homeobox 1 (PDX1) is crucial for pancreas organogenesis, yet the dynamic changes in PDX1 binding in human or mouse developing pancreas have not been examined. To address this knowledge gap, we performed PDX1 ChIP-seq and single-cell RNA-seq using fetal human pancreata. We integrated our datasets with published datasets and revealed the dynamics of PDX1 binding and potential cell-lineage-specific PDX1 bound genes in the pancreas from fetal to adult stages. We identified a core set of developmentally conserved PDX1 bound genes that reveal the broad multifaceted role of PDX1 in pancreas development. Despite the well-known, dramatic changes in PDX1 function and expression, we found that PDX1 bound genes are largely conserved from embryonic to adult stages. This points towards a dual role of PDX1 in regulating the expression of its targets at different ages, dependent on other functionally-congruent or directly-interacting partners. We also showed that PDX1 binding is largely conserved in mouse pancreas. Together, our study reveals PDX1 targets in the developing pancreas in vivo and provides an essential resource for future studies on pancreas development.
Project description:Epigenetic processes play a key role in orchestrating transcriptional regulation during development. The importance of DNA methylation in fetal brain development is highlighted by the dynamic expression of de novo DNA methyltransferases during the perinatal period and neurodevelopmental deficits associated with mutations in the methyl-CpG binding protein 2 (MECP2) gene. However, our knowledge about the temporal changes to the epigenome during fetal brain development has, to date, been limited. We quantified genome-wide patterns of DNA methylation at ∼ 400,000 sites in 179 human fetal brain samples (100 male, 79 female) spanning 23 to 184 d post-conception. We identified highly significant changes in DNA methylation across fetal brain development at >7% of sites, with an enrichment of loci becoming hypomethylated with fetal age. Sites associated with developmental changes in DNA methylation during fetal brain development were significantly underrepresented in promoter regulatory regions but significantly overrepresented in regions flanking CpG islands (shores and shelves) and gene bodies. Highly significant differences in DNA methylation were observed between males and females at a number of autosomal sites, with a small number of regions showing sex-specific DNA methylation trajectories across brain development. Weighted gene comethylation network analysis (WGCNA) revealed discrete modules of comethylated loci associated with fetal age that are significantly enriched for genes involved in neurodevelopmental processes. This is, to our knowledge, the most extensive study of DNA methylation across human fetal brain development to date, confirming the prenatal period as a time of considerable epigenomic plasticity.