Effect of hematopoietic-specific heterozygous loss of Dnmt3a on the molecular pathophysiology of colitis-associated colon cancer (CAC) in a mouse model
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PROVIDER: PRJNA879452 | ENA |
REPOSITORIES: ENA
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Project description:To model clonal hematopoiesis driven by DNMT3A loss-of-function, bone marrow chimerae with Dnmt3a(+/-) (experiment) or Dnmt3a(+/+) (control) were established in C57BL6/J wt mice, followed by standard CAC induction by AOM/DSS
2023-06-12 | GSE213178 | GEO
Project description:Clonal hematopoiesis (CH) is defined as clonal expansion of mutant hematopoietic stem cells absent diagnosis of a hematologic malignancy. Presence of CH in solid tumor patients, including colon cancer, correlates with shorter survival. We hypothesized that bone marrow-derived cells with heterozygous loss-of-function mutations of DNMT3A, the most common genetic alteration in CH, contribute to the pathogenesis of colon cancer. In a mouse model that combines colitis-associated colon cancer (CAC) with experimental CH driven by Dnmt3a+/Δ, we found higher tumor penetrance and increased tumor burden compared with controls. Histopathological analysis revealed accentuated colonic epithelium injury, dysplasia, and adenocarcinoma formation. Transcriptome profiling of colon tumors identified enrichment of gene signatures associated with carcinogenesis, including angiogenesis. Treatment with the angiogenesis inhibitor axitinib eliminated the colon tumor-promoting effect of experimental CH driven by Dnmt3a haploinsufficiency and rebalanced hematopoiesis. This study provides conceptually novel insights into non-tumor-cell-autonomous effects of hematopoietic alterations on colon carcinogenesis and identifies potential therapeutic strategies.
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Project description:Function of Epithelium BRG1 in colitis and CAC
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Project description:Function of Epithelium BRG1 in colitis and CAC II
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Project description:In response to vascular injury, early EPC or Circulating angiogenic cells (CAC) are thought to be recruited to the damaged areas, participating mainly in a paracrine fashion, by releasing pro-angiogenic factors, promoting the mobilization of other cell populations such as the late EPC, or endothelial colony-forming cells (ECFC). ECFC will help by replacing the damaged endothelium and promoting neovascularization. Unfortunately, however, despite the regenerative role, the number and function of EPC are severely affected under pathological conditions, making compulsory to better understand how these cells react under those environments in order to implement their use in regenerative cell therapies. Herein we evaluated, for the first time to our knowledge, the effect of atherosclerotic factors over the paracrine role of CAC, by direct incubation ex vivo of healthy CAC with the secretome of atherosclerotic arteries. The application of a label free proteomics approach allowed the identification of 194 altered proteins in the secretome of pre-conditioned CAC, many of them related, among others, with inhibition of angiogenesis and cell migration. Functional assays corroborated that, after atherosclerotic pre-conditioning, the pro-angiogenic effect of CAC over ECFC was impaired, affecting ECFC migration as well as their ability to form tubules on a basement membrane matrix assay. Up-regulation of several anti-angiogenic proteins in the CAC secretome could help to explain such angiogenic switch which, in turns, could reflect a protective and beneficial effect against the atherosclerotic process.
2021-09-09 | PXD019395 | Pride
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:DNA methylation occurs as 5-methylcytosines mainly at cytosine-guanine dinucleotides, so-called CpG sites, and such methylation is a well-studied epigenetic mechanism for transcriptional regulation. Generally, DNA methylation of the gene promoter is correlated with transcriptional repression. Genomic DNA methylation patterns are established by the actions of the de novo methyltransferases Dnmt3a and Dnmt3b, and are maintained by the methyltransferase Dnmt1. Expression of Dnmt3a mRNA is relatively high in skeletal muscle, suggesting a major role in transcriptional regulation. Also, denervation of skeletal muscle decreased expression of Dnmt3a mRNA, suggesting involvement of Dnmt3a in pathophysiology during atrophy. Decreased regeneration capacity in atrophied skeletal muscle hampers muscle mass recovery after injury and the impaired muscle function, lowers the quality of life. We found that in skeletal muscle of atrophy models, Dnmt3a was decreased. Muscle regeneration was delayed in the skeletal muscle-specific Dnmt3a knockout (Dnmt3a-KO) mice, in which Dnmt3a was deleted in skeletal muscle as well as in satellite cells, important for muscle regeneration. In this study, we used Dnmt3a-KO mice, and attempt to clarify the mechanism of reduced muscle regeneration during atrophy. The microarray data shows that expression of a Gdf/Bmp family protein Gdf5, which suppressed differentiation of satellite cells, is activated in Dnmt3a-KO mice compared with wild-type mice.
2019-04-01 | GSE97340 | GEO
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:MUC1 is a tumor-associated antigen that is aberrantly expressed in cancer and inflammatory bowel disease (IBD). Even though immune cells express low MUC1 levels, their modulations of MUC1 are important in tumor progression. Consistent with previous clinical data that show increased myeloid-derived suppressor cells (MDSCs) in IBD, we now show that down-regulation of MUC1 on hematopoietic cells increases MDSCs in IBD, similar to our data in tumor-bearing mice. We hypothesize that MDSC expansion in IBD is critical for tumor progression. In order to mechanistically confirm the linkage between Muc1 down-regulation and MDSC expansion, we generated chimeric mice that did not express Muc1 in the hematopoietic compartment (KOM-bM-^FM-^RWT). These mice were used in 2 models of colitis and colitis-associated cancer (CAC) and their responses were compared to wildtype chimeras (WTM-bM-^FM-^RWT). KOM-bM-^FM-^RWT mice show increased levels of MDSCs during colitis that was responsible for the larger colon tumors that eventually developed in these mice. Using microarray and qRT-PCR analysis, we observed increased pro-tumorigenic signaling in the colons of KOM-bM-^FM-^RWT mice during colitis as compared to WTM-bM-^FM-^RWT mice. Our RNA (microarray and qRT-PCR analysis) and protein analysis demonstrate increased up-regulation of metalloproteinases, collagenases, defensins, complements, growth factors, cytokines and chemokines in KOM-bM-^FM-^RWT mice as compared to WTM-bM-^FM-^RWT mice. Antibody-mediated depletion of MDSCs in mice during colitis reduced colon tumor formation during CAC. Development of CAC is a serious complication of colitis and our data highlight MDSCs as a targetable link between inflammation and cancer. A total of 12 samples were analysed. RNA was made from the mucosa of the colon of WTM-bM-^FM-^RWT and KOM-bM-^FM-^RWT mice that were either untreated or treated with azoxymethane (AOM) and dextran sodium sulfate (DSS). There are 4 groups, n=3 for each group: untreated WTM-bM-^FM-^RWT mice, untreated KOM-bM-^FM-^RWT mice, AOM+DSS treated WTM-bM-^FM-^RWT mice, AOM+DSS treated KOM-bM-^FM-^RWT mice = 12 samples in total.
2013-05-30 | E-GEOD-47487 | biostudies-arrayexpress
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