Deep learning identifies Pbx1 as a network hub of hematopoietic stem cell aging [26hr ATAC-seq]
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE286955 | GEO | 2026/07/10
REPOSITORIES: GEO
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Project description:Nuclear receptor binding SET domain protein 1 (NSD1) is recurrently mutated in human cancers including acute leukemia. We found that NSD1 knockdown altered erythroid clonogenic growth of human CD34+ hematopoietic cells. Ablation of Nsd1 in the hematopoietic system induced a transplantable erythroleukemia in mice. Despite abundant expression of the transcriptional master regulator GATA1, in vitro differentiation of Nsd1-/- erythroblasts was majorly impaired associated with reduced activation of GATA1-induced targets, while GATA1-repressed target genes were less affected. Retroviral expression of wildtype Nsd1, but not a catalytically-inactive Nsd1N1918Q SET-domain mutant induced terminal maturation of Nsd1-/- erythroblasts. Despite similar GATA1 levels, exogenous Nsd1 but not Nsd1N1918Q significantly increased GATA1 chromatin occupancy and target gene activation. Notably, Nsd1 expression reduced the association of GATA1 with the co-repressor SKI, and knockdown of SKI induced differentiation of Nsd1-/- erythroblasts. Collectively, we identified the NSD1 methyltransferase as a novel regulator of GATA1-controlled erythroid differentiation and leukemogenesis.
2020-04-08 | PXD017657 | Pride
Project description:Gene expression during cellular differentiation is coordinated by combinatorial interactions between transcription factors (TFs) and cofactors at promoters and enhancers. The “master TF” GATA1 coordinates gene transcription in a subset of hematopoietic lineages, including erythroid, megakaryocytic, mast, and eosinophil, while repressing the development of other blood lineages. However, the specific cofactors required for GATA1-activated gene expression during hematopoiesis are incompletely defined. We identified the cofactor KMT2D, an H3K4 methyltransferase that collaborates with H3K27 acetyltransferases to activate transcription, in an unbiased CRISPR/Cas9 screen for epigenetic regulators of erythropoiesis. Loss of KMT2D in human erythroid precursors caused developmental arrest with impaired expression of numerous erythroid genes. Mechanistically, KMT2D colocalized with GATA1 on more than one thousand erythroid enhancers associated with over two hundred erythroid genes. In general, co-occupancy of GATA1 and KMT2D at erythroid enhancers was associated with stronger transcriptional activity than occupancy by GATA1 alone. Acute depletion of KMT2D in erythroid precursors caused rapid reductions of H3K4me1 and H3K27ac on a subset of GATA1-bound enhancers and impaired the expression of canonical erythroid genes, including ZFPM1, SLC4A1, and EPOR. Moreover, acute depletion of GATA1 or KMT2D individually caused downregulation of overlapping gene sets. Thus, KMT2D controls erythropoiesis by selectively activating GATA1-dependent erythroid enhancers. Our studies identify KMT2D as a novel cofactor for transcriptional activation by GATA1 during erythropoiesis. More generally, our findings demonstrate how a lineage-specific TF cooperates with a ubiquitous epigenetic regulator to drive lineage-specific gene expression during cellular differentiation.
2026-04-10 | PXD076443 | Pride
Project description:Myelodysplastic syndromes (MDS) are a group of hematologic neoplasms in which the bone marrow fails to produce enough mature blood cells, leading to peripheral blood cytopenias and myeloproliferation1-3. The average survival time following diagnosis of MDS is 2.5 years4, owing to few treatment options5. Roughly 20-30% of MDS patients progress to acute myeloid leukemia6. Risks of allogeneic bone marrow transplants in elderly patients, together with a dearth of effective FDA-approved drugs, make it imperative to revisit the origins of hematopoietic differentiation defects underlying MDS to identify new druggable targets7-9. We recently reported that haploinsufficiency of the atypical kinase Riok2 (Right open reading frame kinase 2)10 in mice leads to anemia and MDS-associated phenotypes11. However, the underlying molecular mechanisms remain largely unexplored. Here we show that RIOK2 is a master transcription factor that not only drives erythroid lineage commitment, but simultaneously suppresses megakaryocytic and myeloid lineages in primary human stem and progenitor cells. Structural modeling, chromatin immunoprecipitation sequencing, ATAC-sequencing and structure-function domain deletion mutants revealed that RIOK2 activates or represses specific genetic programs in hematopoiesis via its previously unappreciated winged helix-turn-helix DNA-binding domain and two transactivation domains. Mechanistically, RIOK2 functions as a master regulator of hematopoietic lineage commitment by controlling the expression of key lineage-specific transcription factors, such as GATA1, GATA2, SPI1, RUNX3 and KLF1. We also show that GATA1 and RIOK2 function in a positive feedback loop to drive erythroid differentiation. These discoveries present novel therapeutic opportunities to correct hematopoietic differentiation defects in MDS, in the anemia of chronic diseases such as renal failure and inflammation, and in other bone marrow failure disorders.
2021-10-16 | MSV000088238 | MassIVE
Project description:Enhancers of transcription activate transcription via binding of sequence-specific transcription factors to their target sites in chromatin. In this report, we identify GATA1-bound enhancers genome-wide and find a global reorganization of the nucleosomes at these enhancers during differentiation of hematopoietic stem cells (HSCs) to erythrocytes. We show that the catalytic subunit BRG1 of BAF complexes localizes to these enhancers during differentiation and generates a longer nucleosome repeat length surrounding the GATA1 sites by shifting the flanking nucleosomes away. Intriguing, we find that the nucleosome shifting specifically facilitates binding of TAL1 but not GATA1, which subsequently activates transcription of target genes. Human hematopoietic stem cells (referred as CD34+ cells) were differentiated into erythroid lineage expressing the cell surface marker CD36 (referred as CD36+ cells). To study the function of ATP-dependent chromatin remodeling BAF complexes in the establishment of erythroid specific enhancers during differentiation, we mapped the genome-wide binding sites of GATA1 and TAL1, the key transcription regulators of erythroid differentiation, in CD36+ cells, then determined the genomic positions of the catalytic subunit BRG1 of the BAF complexes and the nucleosome landscapes, by ChIP-Seq and Mnase-Seq, respectively, for both HSCs and the differentiated cells. We compared changes in nucleosome landscapes with BRG1 binding at GATA1 and TAL1 binding sites and found that BRG1 binding is correlated with nucleosome shifting away from the binding sites, which is critical for TAL1 binding. To confirm that BRG1 is responsible for the nucleosome shift, we knocked down BRG1 in CD36+ cells and analyzed the nucleosome changes in the knockdown cells. The data indicated that inhibition of BRG1 caused a nucleosome shift towards the GATA1 or TAL1 sites, indicating that BRG1 is indeed responsible for the observed nucleosome shift.
2011-07-01 | E-GEOD-26501 | biostudies-arrayexpress
Project description:Increasing evidence links metabolic activity and cell growth to decline in hematopoietic stem cell (HSC) function during aging. The Lin28b/Hmga2 pathway controls tissue development and in the hematopoietic system the postnatal downregulation of this pathway causes a decrease in self renewal of adult HSCs compared to fetal HSCs. Igf2bp2 is an RNA binding protein and a mediator of the Lin28b/Hmga2 pathway, which regulates metabolism and growth signaling by influencing RNA stability and translation of its target genes. It is currently unknown whether Lin28/Hmga2/Igf2bp2 signaling impacts on aging-associated impairments in HSC function and hematopoiesis. Here, we analyzed homozygous Igf2bp2 germline knockout mice and wildtype control animals to address this question. The study shows that Igf2bp2 deletion rescues aging phenotypes of the hematopoietic system, such as the expansion of HSC numbers in bone marrow and the biased increase of myeloid cells in peripheral blood. This rescue of hematopoietic aging coincides with reduced mitochondrial metabolism and glycolysis in Igf2bp2-/- HSCs compared to Igf2bp2+/+ HSCs. Conversely, Igf2bp2 overexpression activates protein synthesis pathways in HSCs and leads to a rapid loss of self renewal by enhancing myeloid skewed differentiation in an mTOR/PI3K-dependent manner. Together, these results show that Igf2bp2 regulates energy metabolism and growth signaling in HSCs and that the activity of this pathways influences self renewal, differentiation, and aging of HSCs.
2024-05-21 | PXD018535 | Pride
Project description:MTD project_description Inflammation and decreased stem cell function characterize organism aging, yet the relationship between these factors remains incompletely understood. This study shows that aged hematopoietic stem and progenitor cells exhibit increased ground-stage NF-κB activity, which enhances their responsiveness to undergo differentiation and loss of self-renewal in response to inflammation. The study identifies Rad21/cohesin as a critical mediator of NF-κB signals, by increasing chromatin accessibility of inter-/intra-genic and enhancer regions. Rad21/NF-κB are required for normal differentiation, but limit self-renewal of hematopoietic stem cells (HSCs) during aging and inflammation in an NF-κB dependent manner. HSCs from aged mice fail to downregulate Rad21/cohesin and inflammation/differentiation inducing signals in the resolution phase after acute inflammation. and The inhibition of cohesin/NF-κB is sufficient to revert the hypersensitivity of aged HSPCs to inflammation-induced differentiation. During aging, myeloid-biased HSCs with disrupted and naturally occurring reduced expression of Rad21/cohesin are increasingly selected over lymphoid-biased HSCs. Together, Rad21/cohesin mediated NF-κB signaling limits HSPC function during aging and selects for cohesin deficient HSCs with myeloid skewed differentiation.
2018-11-28 | PXD011537 | Pride
Project description:Missense mutations in transcription factor GATA1 underlie several distinct forms of anemia and thrombocytopenia. Clinical severity depends on the site and type of substitution, and distinct substiutions of the same residue produce disparate phenotypes. To investigate the effect of GATA1 missense mutations on erythroid differentiation we expressed conditionally activated wild type or mutant versions of GATA1 in GATA1-null G1E cells. We used gene expression microarrays to explore how GATA1 missense mutations affect erythroid transcription programs. GATA1-null G1E cells ectopically expressing conditionally activated versions of GATA1 (GATA1-ER, GATA1(R216Q)-ER, GATA1(R216W)-ER, GATA1(D218G)-ER, or GATA1(D218Y)-ER) were treated with estradiol for 24 hours to initiate erythroid differentiation. Total RNA from treated cells was extracted for Affymetrix microarray. All data were generated from three biological replicates. Transcript levels were compared in wild type vs. mutant lines.
2013-03-04 | E-GEOD-43356 | biostudies-arrayexpress
Project description:The transcription factor GATA1 has pleiotropic hematopoietic functions, particularly in erythroid and megakaryocytic ontogeny. While mechanistic investigations have uncovered many facets of GATA1 biology, how GATA1 co-regulates divergent cell fates remains incompletely characterized. We previously described that loss of Stag2, a member of the cohesin complex and a recurrent mutational target in myelodysplastic syndrome (MDS) and myeloid leukemia of Down Syndrome, results in altered chromatin accessibility, transcription factor function, and cell differentiation. Hence, we hypothesized that chromatin accessibility determines GATA1 cistrome specificity and lineage fate decisions. To understand the connection between chromatin accessibility and GATA1, we comprehensively studied erythropoiesis in Stag2∆ mice. Defects in Stag2-deficient hematopoiesis included reduced numbers of erythroid progenitors (EryPs), impaired terminal erythroid differentiation, increased number of MkPs, and increased megakaryocytes. RNA- and ATAC-sequencing of EryPs revealed altered patterns of Gata1 target gene expression with altered accessibility in conjunction with loss of expression of erythroid targets and gain of megakaryocyte targets. Despite unchanged Gata1 expression, Gata1 occupancy was reprogrammed from erythroid to megakaryocyte targets with Fli1 motifs enriched at Stag2∆ Gata1 binding sites. Functionally, we observed that Stag2-deficient EryPs have diminished erythroid output and augmented megakaryocyte output in orthogonal differentiation assays, which was partially reversed with Fli1 knockdown. Human models and primary MDS patients recapitulated the essential phenotypic and molecular features of our in vivo murine MDS model. Collectively, this study establishes chromatin accessibility as a determinant of transcription factor binding specificity, revealing an accessibility-driven Gata1 retargeting mechanism underlying MDS dyserythropoiesis.
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Project description:Ribosomopathies constitute a range of disabling conditions associated with defective protein synthesis mainly affecting hematopoietic stem cells (HSCs) and erythroid development. Here we demonstrate that deletion of Polypyrimidine Tract Binding Protein 1 (PTBP1) in the hematopoietic compartment led to the development of a ribosomopathy-like condition. Specifically, loss of PTBP1 was associated with a decrease in HSC self-renewal, erythroid differentiation and protein synthesis. Consistent with its function as a splicing regulator, PTBP1 deficiency led to splicing defects in hundreds of genes and we demonstrate that the up-regulation of a specific isoform of CDC42 could partly mimic the protein synthesis defect associated with loss of PTBP1. Furthermore, PTBP1 deficiency was associated with a marked defect in ribosome biogenesis and a selective reduction in the translation of mRNAs encoding ribosomal proteins. Collectively, this work identifies PTBP1 as a key integrator of ribosomal functions and highlights the broad functional repertoire of RNA binding proteins.
2022-05-04 | PXD023879 | Pride
Project description:<p>Methionine cycle plays critical roles in cell fate determination by shaping epigenetic landscape, yet its function in human erythropoiesis remains undefined. Here, we show that disruption of methionine metabolism by compromising key enzyme adenosylhomocysteinase (AHCY) reshapes H3K4me3 landscape, causing erythroid cell fate reprogramming. AHCY deficiency severely impaired erythroid differentiation and expansion, leading to the generation of non-erythroid lineage hematopoietic cells, including stem/progenitor cells and immune cells, as evidenced by single-cell RNA sequencing, Pseudo temporal analysis delineated a precise dedifferentiation trajectory, revealing erythroblasts transitioning back to MEPs and HSCs. Moreover, human hematopoietic system could be reconstituted in the immunodeficient NCG-X mice by transplanting AHCY deficient erythroblasts. Mechanistically, AHCY deficiency reduced global H3K4me3 levels and altered its genomic distribution, resulting in the upregulated expression of non-erythroid transcription factors and downregulated expression of erythrocyte lineage-specific transcription factors. Integrated single-cell analyses identified transitional states with diminished AHCY in the erythroblasts of acute myeloid leukemia (AML) patient. Further flow cytometry confirmed the reduced H3K4me3 level in patient derived erythroid cells. Erythroblast isolated from AML patients with reduced H3K4me3 exhibited dedifferentiation potential into progenitor-like states. Our findings reveal a metabolic-epigenetic axis governing cell fate reprogramming in human erythropoiesis and provide insights into leukemia associated anemia.</p>
2026-06-10 | MTBLS10469 | MetaboLights