Growth disrupting mutations in epigenetic regulatory molecules are associated with abnormalities of epigenetic aging
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE128801 | GEO | 2019/05/19
REPOSITORIES: GEO
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Project description:Purpose: DNA methyltransferase 3A (DNMT3A) mediates de novo DNA methylation. Mutations in DNMT3A are associated with hematological malignancies, most frequently acute myeloid leukemia. DNMT3A mutations are hypothesized to establish a pre-leukemic state, rendering cells vulnerable to secondary oncogenic mutations and malignant transformation. However, the mechanisms by which DNMT3A mutations contribute to leukemogenesis are not well-defined. Methods: Methylated DNA immunoprecipitation (MeDIP) was used to detect regional differences in DNA methylation between DNMT3A WT and MT clones. DNA extraction of WTblk, WT1, MT1, MT2, and MT4 cell lines was performed as previously described. 5-mC profiling, fragmentation, library preparation and sequencing were performed by Otogenetics (Atlanta, GA, USA). In brief, paired-end libraries were generated using the Illumina TruSeq DNA sample preparation kit. Illumina HiSeq2500 was used for sequencing with a paired-end sequencing length of 100-125 bp and approximately 40 million reads per sample. Results: We attempted to identify differentially methylated genes based on DNMT3A mutation status and found very few regions of differential methylation between WT and MT cell lines (Figure 3C), which did not exceed the number of regions expected to exhibit differential methylation by chance alone. These data suggest that regional methylation patterns do not differ between DNMT3A MT and WT cell lines in our gene-edited K562 cells. Conclusions: CRISPR/Cas9-mediated DNMT3A-mutated K562 cells may be used to model effects of DNMT3A mutations in human cells. Our findings implicate aberrant splicing and induction of genomic instability as potential mechanisms by which DNMT3A mutations might predispose to malignancy.
2018-01-09 | GSE96577 | GEO
Project description:DNA Methyltransferase 3A (DNMT3A) is an important facilitator of differentiation of both embryonic and hematopoietic stem cells. Heterozygous germline mutations in DNMT3A lead to Tatton-Brown-Rahman Syndrome (TBRS), characterized by obesity and excessive height. While DNMT3A is known to impact feeding behavior via the hypothalamus, here we investigated a role in adipocyte progenitors utilizing heterozygous knockout mice that recapitulate cardinal TBRS phenotypes. These mice become morbidly obese due to adipocyte enlargement and tissue expansion. Adipose tissue in these mice exhibited defects in preadipocyte maturation and precocious activation of inflammatory gene networks, including interleukin-6 signaling. Adipocyte progenitor cell lines lacking DNMT3A exhibited aberrant differentiation. Furthermore, mice in which Dnmt3a was specifically ablated in adipocyte progenitors showed enlarged fat depots and increased progenitor numbers, partly recapitulating the TBRS obesity phenotypes. Loss of DNMT3A led to constitutive DNA hypomethylation, such that the DNA methylation landscape of young adipocyte progenitors resemble that of older wild-type mice. Together, our results demonstrate that DNMT3A coordinates both the central and local control of energy storage required to maintain normal weight and prevent inflammatory obesity.
2022-05-10 | GSE164892 | GEO
Project description:Purpose: DNA methyltransferase 3A (DNMT3A) mediates de novo DNA methylation. Mutations in DNMT3A are associated with hematological malignancies, most frequently acute myeloid leukemia. DNMT3A mutations are hypothesized to establish a pre-leukemic state, rendering cells vulnerable to secondary oncogenic mutations and malignant transformation. However, the mechanisms by which DNMT3A mutations contribute to leukemogenesis are not well-defined. Methods: Whole-exome sequencing of extracted DNA was performed to confirm DNMT3A mutations. Library construction, exon capture, and sequencing was performed by Otogenetics (Atlanta, GA, USA). In brief, paired-end libraries were generated using the Illumina TruSeq DNA sample preparation kit. Exons were enriched using the Agilent Human All Exon V5 (51 Mb) capture system. Illumina HiSeq2500 was used for sequencing with a paired-end sequencing length of 100-125 bp and approximately 70 million reads per sample. Results: the DNMT3A mutations induced by K562 cells were transfected with a plasmid encoding Cas9, a CRISPR guide-RNA (gRNA) targeting the DNMT3A gene, and green fluorescent protein (GFP) followed by single-cell sorting. GFP-positive single cell clones were genotyped to confirm the presence of DNMT3A mutations. MT2-MT5 were verified by analysis of whole-exome sequencing data, and WTblk and WT1 were again confirmed to have no mutations in the DNMT3A gene. Conclusions: CRISPR/Cas9 gene editing allowed the generation of DNMT3A-mutated K562 cells that may be used to model effects of DNMT3A mutations in human cells. Our findings implicate aberrant splicing and induction of genomic instability as potential mechanisms by which DNMT3A mutations might predispose to malignancy.
2018-01-09 | GSE96625 | GEO
Project description:Aberrant DNA methylation of gene promoters is a hallmark of AML. To define more precisely how cytosine methylation is redistributed in AML, we performed base-pair resolution methylome sequencing in 119 patients. We find that leukemic DNA methylation patterning is tightly linked to somatic mutations and primarily driven by regulatory elements outside of promoters and by CpG shores as opposed to CpG islands. Active enhancers displayed much stronger focal differential methylation than promoters and were generally aberrantly hypomethylated except in IDH2 mutant and CEBPA silenced AMLs. AMLs with dominant hypermethylation feature greater epigenetic disruption of promoters. Those with dominant hypomethylation, such as DNMT3A mutated AMLs, display greater disruption of distal and intronic regions. IDH mutant AMLs manifest profound hypermethylation whereas DNMT3A mutant AMLs manifest profound hypomethylation of a different set of CpGs. In striking contrast, AMLs with co-occurring IDH1 and DNMT3A mutations exhibited epigenetic antagonism in which most CpGs affected by either mutation alone were no longer affected in the double mutant cases.
2017-04-28 | GSE96744 | GEO
Project description:DNA methyltransferases DNMT3A- and DNMT3B-mediated de novo DNA methylation critically regulates epigenomic and transcriptomic patterning during development. The hotspot DNMT3A mutations at the site of Arg822 (R882) promote macro-oligomer formation, leading to aberrant DNA methylation that in turn contributes to pathogenesis of acute myeloid leukemia (AML). However, the molecular basis underlying the hotspot mutation-induced functional mis-regulation of DNMT3A remains unclear. Here, we report the crystal structure of DNMT3A methyltransferase (MTase) domain, revealing a molecular basis for its DNMT3B-distinct oligomerization behavior. Introducing DNMT3B-converting mutations to DNMT3A R882 mutants also led to structure determination of R882H- and R882C-mutated DNMT3A, which show enhanced intermolecular contacts than wild-type DNMT3A. Consistently, our in vitro and genomic DNA methylation analyses reveal that the DNMT3B-converting mutations eliminate the gain-of-function effect of the DNMT3A R882 mutations in cells. Together, this study provides mechanistic insights into DNMT3A R882 mutation-triggered aberrant oligomerization and DNA hypomethylation in AML, with important implications in cancer therapy.
2023-12-31 | GSE225828 | GEO
Project description:DNA methyltransferases DNMT3A- and DNMT3B-mediated de novo DNA methylation critically regulates epigenomic and transcriptomic patterning during development. The hotspot DNMT3A mutations at the site of Arg822 (R882) promote macro-oligomer formation, leading to aberrant DNA methylation that in turn contributes to pathogenesis of acute myeloid leukemia (AML). However, the molecular basis underlying the hotspot mutation-induced functional mis-regulation of DNMT3A remains unclear. Here, we report the crystal structure of DNMT3A methyltransferase (MTase) domain, revealing a molecular basis for its DNMT3B-distinct oligomerization behavior. Introducing DNMT3B-converting mutations to DNMT3A R882 mutants also led to structure determination of R882H- and R882C-mutated DNMT3A, which show enhanced intermolecular contacts than wild-type DNMT3A. Consistently, our in vitro and genomic DNA methylation analyses reveal that the DNMT3B-converting mutations eliminate the gain-of-function effect of the DNMT3A R882 mutations in cells. Together, this study provides mechanistic insights into DNMT3A R882 mutation-triggered aberrant oligomerization and DNA hypomethylation in AML, with important implications in cancer therapy.
2023-12-31 | GSE226062 | GEO
Project description:Aberrant DNA methylation of gene promoters is a hallmark of AML. To define how cytosine methylation is redistributed in AML more precisely we performed base-pair resolution methylome sequencing in 119 patients. We find that leukemic DNA methylation patterning is tightly linked to somatic mutations and primarily driven by regulatory elements outside of promoters and by CpG shores as opposed to CpG islands. Active enhancers displayed much stronger focal differential methylation than promoters and were generally aberrantly hypomethylated except in IDH2 mutant and CEBPA silenced AMLs. AMLs with dominant hypermethylation feature greater epigenetic disruption of promoters. Those with dominant hypomethylation, such as DNMT3A mutated AMLs, display greater disruption of distal and intronic regions. IDH mutant AMLs manifest profound hypermethylation whereas DNMT3A mutant AMLs manifest profound hypomethylation of a different set of CpGs. In striking contrast, AMLs with co-occurring IDH1 and DNMT3A mutations exhibited epigenetic antagonism in which most CpGs affected by either mutation alone were no longer affected in the double mutant cases. These patients featured a unique gene expression profile featuring deregulated expression of RAS pathway that was not linked to DNA methylation.
2017-04-19 | GSE86952 | GEO
Project description:Purpose: DNA methyltransferase 3A (DNMT3A) mediates de novo DNA methylation. Mutations in DNMT3A are associated with hematological malignancies, most frequently acute myeloid leukemia. DNMT3A mutations are hypothesized to establish a pre-leukemic state, rendering cells vulnerable to secondary oncogenic mutations and malignant transformation. However, the mechanisms by which DNMT3A mutations contribute to leukemogenesis are not well-defined. Methods: mRNA profiles of wild-type (WT) and DNMT3A mutated k562 cell lines were generated by deep sequencing, using Illumina HiSeq2500. Sequence reads were trimmed to remove possible adapter sequences and nucleotides with poor quality at the ends. Remaining sequence reads were then aligned to the human reference genome (hg19) using Tophat2. Gene read counts were measured using FeatureCounts and FPKM values were calculated with cufflinks. edgeR was used to identify differentially expressed genes between conditions, and topGO was used for annotation (Alexa, Rahnenfuhrer, and Lengauer, 2006). Sample comparison for differential gene expression was as follows: WTblk and WT1 versus MT2, MT3, MT4, and MT5. Gene enrichment set analysis (GSEA) was conducted with KEGG, Biocarta, and Reactome pathway datasets (Subramanian et al., 2005). Results: DNMT3A-mutated cells displayed impaired differentiation capacity. RNA-seq was used to compare transcriptomes of DNMT3A-mutated and WT cells; DNMT3A ablation resulted in downregulation of genes involved in spliceosome function, causing dysfunction of RNA splicing. Unexpectedly, we observed DNMT3A-mutated cells to exhibit marked genomic instability and an impaired DNA damage response compared to WT. Conclusions: CRISPR/Cas9-mediated DNMT3A-mutated K562 cells may be used to model effects of DNMT3A mutations in human cells. Our findings implicate aberrant splicing and induction of genomic instability as potential mechanisms by which DNMT3A mutations might predispose to malignancy.
2018-01-09 | GSE96634 | GEO
Project description:Mutations in DNA methyltransferase 3A (DNMT3A) have been detected in autism and related disorders, but how these mutations disrupt nervous system function is unknown. Here we define the effects of neurodevelopmental disease-associated DNMT3A mutations. We show that diverse mutations affect different aspects of protein activity yet lead to shared deficiencies in neuronal DNA methylation. Heterozygous DNMT3A knockout mice mimicking DNMT3A disruption in disease display growth and behavioral alterations consistent with human phenotypes. Strikingly, in these mice we detect global disruption of neuron-enriched non-CG DNA methylation, a binding site for the Rett syndrome protein MeCP2. Loss of this methylation leads to enhancer and gene dysregulation that overlaps with models of Rett syndrome and autism. These findings define effects of DNMT3A haploinsufficiency in the brain and uncover disruption of the non-CG methylation pathway as a convergence point across neurodevelopmental disorders.
2020-11-13 | GSE147818 | GEO
Project description:Mutations in DNA methyltransferase 3A (DNMT3A) have been detected in autism and related disorders, but how these mutations disrupt nervous system function is unknown. Here we define the effects of neurodevelopmental disease-associated DNMT3A mutations. We show that diverse mutations affect different aspects of protein activity yet lead to shared deficiencies in neuronal DNA methylation. Heterozygous DNMT3A knockout mice mimicking DNMT3A disruption in disease display growth and behavioral alterations consistent with human phenotypes. Strikingly, in these mice we detect global disruption of neuron-enriched non-CG DNA methylation, a binding site for the Rett syndrome protein MeCP2. Loss of this methylation leads to enhancer and gene dysregulation that overlaps with models of Rett syndrome and autism. These findings define effects of DNMT3A haploinsufficiency in the brain and uncover disruption of the non-CG methylation pathway as a convergence point across neurodevelopmental disorders.
2020-11-13 | GSE147898 | GEO