Loss of Dnmt3a impairs hematopoietic homeostasis and myeloid cell skewing via the PI3Kinase pathway II
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE208437 | GEO | 2022/11/30
REPOSITORIES: GEO
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Project description:To investigate the role of PI3K in Dnmt3a loss driven leukemia, bone marrow cells from wildtype or Dnmt3a knockout mice were assayed for differential gene expression.The signaling pathways by which DNMT3A mutations contribute to myeloid transformation are poorly understood. We investigated that loss of Dnmt3a in HSC/Ps results in myeloproliferation, which is associated with hyperactivation of the PI3Kinase pathway.
2022-11-30 | GSE208435 | GEO
Project description:Transcriptional profiling of mouse lung tumors comparing Dnmt3a KO/K-ras G12D mutant with Dnmt3a WT/K-ras G12D mutant. The goal is to search for the difference of mRNA abundance between Dnmt3a KO and WT tumors. Two-condition experiment, KO vs. WT tissure. Biological replicates: 12.
2011-10-25 | E-GEOD-32415 | biostudies-arrayexpress
Project description:DNMT3A (which encodes a de novo DNA methyltransferase) is one of the most frequently mutated genes in AML genomes. Point mutations at position R882 have been shown to cause a dominant negative loss of DNMT3A methylation activity, but 15% of DNMT3A mutations are predicted to produce truncated proteins, which could either have dominant negative activities, or cause loss-of-function and haploinsufficiency. We demonstrate that three of these mutants produce truncated, inactive proteins that do not dimerize with wild-type DNMT3A, strongly supporting the haploinsufficiency hypothesis. We therefore evaluated hematopoiesis in mice heterozygous for a constitutive null Dnmt3a mutation: unmanipulated mice developed myeloid skewing over time, and their stem/progenitor cells exhibited a long-term competitive transplantation advantage. Dnmt3a+/- mice spontaneously developed transplantable myeloid malignancies after a long latent period, and three of 12 tumors tested had cooperating mutations in the Ras- MAPK pathway. The residual Dnmt3a allele was neither mutated nor downregulated in tumors. The bone marrow cells of Dnmt3a+/- mice had a subtle but significant DNA hypomethylation phenotype that was not associated with gene dysregulation. These data demonstrate that haploinsufficiency for DNMT3A alters hematopoiesis, and predisposes mice (and probably humans) to myeloid malignancies by a mechanism that is not yet clear.
2017-08-01 | GSE100702 | GEO
Project description:Cytogenetically normal acute myeloid leukemia (CN-AML) represents nearly 50% of human acute myeloid leukemia (AML) cases with a 5-year overall survival of approximately 30%. In CN-AML with poorer prognosis, mutations in the de novo DNA methyltransferase (DNMT3A) and the FMS-like tyrosine kinase 3 (Flt3) commonly co-occur (1-3). We demonstrate that mice with Flt3-internal-tandem duplication (Flt3ITD) and inducible deletion of Dnmt3a spontaneously develop a rapidly-lethal, completely-penetrant, and transplantable AML of normal karyotype. These murine AML retain a single Dnmt3a floxed allele, revealing the oncogenic potential of Dnmt3a haploinsufficiency. FLT3-ITD/DNMT3A-mutant primary human and murine AML demonstrate a similar pattern of global DNA methylation. In the murine model, rescuing DNMT3A expression was accompanied by DNA re-methylation and loss of clonogenic potential, suggesting that Dnmt3a-mutant oncogenic effects are reversible. Differentially methylated genomic regions were associated with changes in the expression of nearby genes. Moreover, dissection of the cellular architecture of the AML model using single-cell RNA-Seq, flow cytometry and colony assays identified clonogenic subpopulations that differentially express genes that are sensitive to the methylation of nearby genomic loci and varied in response to Dnmt3a levels. Thus, Dnmt3a haploinsufficiency transforms Flt3ITD myeloproliferative disease by modulating methylation-sensitive gene expression within a clonogenic AML subpopulation. To identify the gene expression changes associated with Dnmt3a loss of function in human and murine Flt3-ITD and Dnmt3a-mutant AML (Bulk RNA-Seq).
2016-03-27 | E-GEOD-77846 | biostudies-arrayexpress
Project description:Cytogenetically normal acute myeloid leukemia (CN-AML) represents nearly 50% of human acute myeloid leukemia (AML) cases with a 5-year overall survival of approximately 30%. In CN-AML with poorer prognosis, mutations in the de novo DNA methyltransferase (DNMT3A) and the FMS-like tyrosine kinase 3 (Flt3) commonly co-occur (1-3). We demonstrate that mice with Flt3-internal-tandem duplication (Flt3ITD) and inducible deletion of Dnmt3a spontaneously develop a rapidly-lethal, completely-penetrant, and transplantable AML of normal karyotype. These murine AML retain a single Dnmt3a floxed allele, revealing the oncogenic potential of Dnmt3a haploinsufficiency. FLT3-ITD/DNMT3A-mutant primary human and murine AML demonstrate a similar pattern of global DNA methylation. In the murine model, rescuing DNMT3A expression was accompanied by DNA re-methylation and loss of clonogenic potential, suggesting that Dnmt3a-mutant oncogenic effects are reversible. Differentially methylated genomic regions were associated with changes in the expression of nearby genes. Moreover, dissection of the cellular architecture of the AML model using single-cell RNA-Seq, flow cytometry and colony assays identified clonogenic subpopulations that differentially express genes that are sensitive to the methylation of nearby genomic loci and varied in response to Dnmt3a levels. Thus, Dnmt3a haploinsufficiency transforms Flt3ITD myeloproliferative disease by modulating methylation-sensitive gene expression within a clonogenic AML subpopulation. To identify the gene expression changes associated with Dnmt3a loss of function in human and murine Flt3-ITD and Dnmt3a-mutant AML (Single Cell RNA-Seq).
2016-03-27 | E-GEOD-77847 | biostudies-arrayexpress
Project description:Epigenetic modifying enzymes DNMT3A and TET2 are recurrently mutated in hematological disorders despite possessing opposing biochemical functions in the DNA methylation processes. Using conditional ablation, we show these contrasting genotypes result in different functional effects in hematopoietic stem cells (HSCs). Loss of Dnmt3a bestows enhanced self-renewal on HSCs in serial, competitive repopulation assays while Tet2 loss functionally depletes HSCs after a tertiary transplant despite an initial competitive advantage. Moreover, loss of Tet2 sensitizes HSCs to the addition of a common leukemic driver mutation Flt3-ITD. Tet2-null mice experience a 5-fold decrease in median survival time when combined with Flt3-ITD while that of Dnmt3a-null mice decreases 1.5-fold. Molecular characterization of transcriptomes and chromatin accessibility reflects the functional differences between the genotypes as Dnmt3a-null cells reside in a more stem cell-like state while Tet2 loss leads to functional attrition of down-stream progenitors. These data further prove that DNMT3A and TET2 mutations lead HSCs down different molecular and functional pathways despite similar disease destinations.
2020-04-01 | GSE139911 | GEO
Project description:Transcriptional profiling of mouse lung tumors comparing Dnmt3a KO/K-ras G12D mutant with Dnmt3a WT/K-ras G12D mutant. The goal is to search for the difference of mRNA abundance between Dnmt3a KO and WT tumors.
2011-10-26 | GSE32415 | GEO
Project description:Deleterious somatic mutations in DNMT3A or TET2 are associated with clonal expansion of haematopoietic cells and higher risk of cardiovascular disease (CVD). In mice, most studies have indicated an over-activation of the inflammatory program in myeloid cells with reduced DNMT3A or TET2 expression. However, the effect of loss of function of DNMT3A and TET2 in human myeloid cells remains poorly understood. Here, we investigated the roles of DNMT3A and TET2 in normal human monocyte- derived macrophages (mDM), in mDM isolated from individuals with DNMT3A or TET2 mutations and in macrophages isolated from human atherosclerotic plaques. Using a combination of transcriptomic, epigenetic, and imaging assays, we provide evidence that, in addition to distinct roles in regulation of macrophage gene expression, DNMT3A and TET2 share a common role in maintaining mitochondrial DNA integrity by regulating the expression of Transcription Factor A, Mitochondria ( TFAM ). This shared function is dependent on interactions of DNMT3A and TET2 with RBPJ and ZNF143 at regulatory elements in the TFAM gene. Experimental reduction of DNMT3A or TET2 expression in normal human mDMs results in downregulation of TFAM, release of mtDNA into the cytoplasm and consequent activation of a type I interferon response mediated by cGAS. Single-cell RNA-seq analysis of mDMs from individuals with heterozygous loss-of-function mutations in DNMT3A and TET2 revealed a similar transcriptional signature. In addition, single-cell RNA-seq analysis of normal mDM and macrophages residing in human atherosclerotic plaques revealed higher expression of type I IFN signature genes specifically in cells with lower DNMT3A or TET2 expression. The production of IFN as a component of the type I IFN response induces activation of interferon-stimulated genes in neighbouring cells, representing a mechanism by which partial loss of function of DNMT3A or TET2 in a small fraction of cells could exert pathogenic effects in the artery wall. These findings suggest that targeting the type I IFN pathway may have therapeutic value in reducing risk of cardiovascular disease in patients with DNMT3A or TET2 mutations.
2022-08-05 | GSE206030 | GEO
Project description:To examine whether Dnmt3a deficiency resulted in genomic methylation changes we performed an unbiased methylome analysis. Methylated DNA isolated from three Dnmt3a deficient and two WT tumors was immunoprecipitated and subjected to high throughput sequencing (MeDIP-Seq). We observed that genes that were less expressed in Dnmt3a deficient tumors tended to have lower methylation levels in gene bodies. Examination of methylcytosine in two tumor types
2011-10-25 | E-GEOD-32484 | biostudies-arrayexpress
Project description:Loss of function mutations in the DNA methyltransferase DNMT3A are highly recurrent in acute myeloid leukemia (AML). DNMT3A and DNMT3B encode the two methyltransferases that are primarily responsible for the de novo methylation of specific DNA sequences during cellular differentiation. DNMT3A mutations are rarely found in AML patients with translocations that create oncogenic fusion genes (e.g. PML-RARA, RUNX1-RUNX1T1, CBFB-MYH11, and MLL-X). To begin to define the reasons why these mutations do not occur together, we used retroviral vectors to express PML-RARA, RUNX1-RUNX1T1, and MLL-AF9 in the bone marrow cells of wild type (WT) or Dnmt3a deficient mice; we also examined the hematopoietic phenotypes of Ctsg-PML-RARA animals (which express PML-RARA in early hematopoietic progenitors and myeloid precursors) with and without Dnmt3a. We demonstrated that the methyltransferase activity of Dnmt3a (but not Dnmt3b) is required for aberrant self-renewal ex vivo that is driven by PML-RARA (but not RUNX1-RUNX1T1 or MLL-AF9); furthermore, the PML-RARA-driven competitive transplantation advantage and leukemia generation both required Dnmt3a. Together, these findings demonstrate that PML-RARA is specifically dependent on Dnmt3a to initiate APL in mice, and may explain why loss-of-function DNMT3A mutations are not found in patients with acute promyelocytic leukemia.
2015-10-01 | GSE68844 | GEO