Effect of GFI1B ectopic expression in the hematopoietic or endothelial commitment of human iPSC derived CD34+CD43-CD73- hemogenic endothelium (HE)
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE246386 | GEO | 2024/12/18
REPOSITORIES: GEO
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Project description:The transcription factor Growth Factor Independence 1B (GFI1B) recruits Lysine Specific Demethylase 1A (LSD1/KDM1A) to stimulate gene programs relevant for megakaryocyte and platelet biology. Inherited pathogenic GFI1B variants result in thrombocytopenia and bleeding propensities with varying intensity. Whether these affect similar gene programs is unknow. Here we studied transcriptomic effects of four patient-derived GFI1B variants (GFI1BT174N,H181Y,R184P,Q287*) in MEG01 megakaryoblasts. Compared to normal GFI1B, each variant affected different gene programs with GFI1BQ287* uniquely failing to repress myeloid traits. In line with this, single cell RNA-sequencing of induced pluripotent stem cell (iPSC)-derived megakaryocytes revealed a 4.5-fold decrease in the megakaryocyte/myeloid cell ratio in GFI1BQ287* versus normal conditions. Inhibiting the GFI1B-LSD1 interaction with small molecule GSK-LSD1 resulted in activation of myeloid genes in normal iPSC-derived megakaryocytes similar as observed for GFI1BQ287* iPSC-derived megakaryocytes. Thus, GFI1B and LSD1 facilitate gene programs relevant for megakaryopoiesis while simultaneously repressing programs that induce myeloid differentiation.
2024-03-28 | PXD050401 | Pride
Project description:The zinc finger protein and SNAG domain transcription factor Gfi1b is highly expressed in hematopoietic stem cells (HSC) and in megakaryocytes (MKs). Deletion of Gfi1b in mice leads to a drastic expansion of both cell types, suggesting that Gfi1b controls their proliferation. Here we present evidence that Gfi1b exerts this control by modulating the Wnt/beta-catenin signaling pathway. We can show that Gfi1b binds to beta-catenin and is part of a larger complex that contains β-catenin co-factors. Gfi1b activates beta-catenin/TCF mediated transcription and is required for the activity of beta-catenin target gene promoter driven reporter genes in vivo. This is dependent of the ability of Gfi1b to recruit the histone modifying enzyme lysine demethylase 1 (LSD1) to β-catenin containing complexes. Moreover, LSD1 enhances the Gfi1b-mediated activation of beta-catenin/TCF dependent transcription. Both Gfi1b deficient HSCs and MKs show de-regulation of expression of many sets on Wnt/β-catenin target genes and Gfi1b and β-catenin co-occupy the promoters of many common target genes. Finally, activating the Wnt/β-catenin signaling pathway in Gfi1b deficient HSCs and MKs significantly reduces their expansion, which confirms that Gfi1b is a critical factor controlling the cellularity of HSCs and MKs and exerts this function by regulating the Wnt/β-catenin pathway in these cells.
2017-09-01 | GSE85737 | GEO
Project description:Dominant-negative mutations in transcription factor Growth Factor Independence-1B (GFI1B) cause a bleeding disorder characterized by a plethora of megakaryocyte and platelet abnormalities. The deregulated molecular mechanisms and pathways are unknown. Here we show that normal and mutant GFI1B interacted most strongly with the LSD1-RCOR-HDAC corepressor complex in megakaryoblasts. Sequestration of this complex by mutant GFI1B and chemical separation of GFI1B from LSD1 induced abnormalities in normal megakaryocytes comparable to those seen in patients. Megakaryocytes derived from GFI1B-mutant induced pluripotent stem cells (iPSC) also phenocopied abnormalities seen in patients. Proteome studies on normal and mutant iPSC-derived megakaryocytes identified a multitude of deregulated pathways downstream of mutant GFI1B. Proteome studies on primary normal and GFI1B-mutant platelets showed reduced expression of proteins implicated in platelet function, and sustained expression of proteins normally downregulated during megakaryocyte differentiation. Thus, GFI1B regulates a broad developmental program during megakaryopoiesis. Mutant GFI1B deregulates this program through LSD1-RCOR-HDAC sequestering.
2019-01-25 | PXD009020 | Pride
Project description:Gfi1b is a DNA binding transcriptional repressor highly expressed in hematopoietic stem cells (HSCs) and megakaryocytes (MKs). Gfi1b deficiency leads to the expansion of both cell types and abrogates the ability of MKs to respond to integrin substrates with spreading and movement. Here we show that Gfi1b is present in complexes with ²-catenin and its co-factors Pontin52, CHD8, TLE3 and CtBP1 and can regulate Wnt/²-catenin dependent gene expression. In reporter assays, Gfi1b can activate TCF-dependent transcription and this activation is enhanced upon treatment with Wnt3a. This requires the interaction between Gfi1b and lysine demethylase 1 (LSD1), but is independent of the ability of Gfi1b to bind DNA. This suggests that a tripartite ²-catenin/Gfi1b/LSD1 complex exists that regulates Wnt/²-catenin target genes. Consistently, expression of many canonical Wnt/²-catenin target genes is deregulated in Gfi1b-deficient cells and many of these target genes are co-occupied by Gfi1b, ²-catenin and LSD1 at promoter sites. When Gfi1b deficient cells were treated with Wnt3a, their normal cellularity was restored and Gfi1b-deficient MKs regained their ability to spread on integrin substrates. This suggests that Gfi1b controls both the cellularity and functional integrity of HSCs and MKs by regulating Wnt/²-catenin signaling pathway.
2019-02-21 | GSE117944 | GEO
Project description:Mutations in transcription factor Growth Factor Independence 1B (GFI1B) cause inherited bleedings with varying intensity possibly caused by different effects on the transcriptional function of GFI1B. We studied transcriptomic changes of normal and GFI1BT174N,H181Y,R184P,Q287* mutants in megakaryoblast MEG01 cells using RNA-sequencing. Compared to normal GFI1B each variant affected different gene modules with limited overlap between variants. Remarkably, GFI1BQ287* specifically activated a myeloid-associated gene module. Based on this finding we studied megakaryocyte differentiation using normal and GFI1BQ287* patient-derived induced pluripotent stem cells (IPSC) followed by single cell RNA-sequencing. This revealed a 45-fold decrease in the megakaryocyte/myeloid cell ratio in the GFI1BQ287* versus control condition. Moreover, myeloid specific genes were expressed within GFI1BQ287* but not normal megakaryocytes. Finally, we studied how megakaryocyte development was affected by inhibiting binding of GFI1B to Lysine Specific Demethylase 1 (LSD1), an interaction required for megakaryocyte development. Treatment of both MEG01 cells and normal IPSC-derived developing megakaryocytes with the small-molecule inhibitor GSK-LSD1 resulted in profound activation of myeloid gene programs within megakaryocytes, while the IPSC-derived megakaryocyte/myeloid ratio dropped two-fold. We conclude that GFI1B and LSD1 suppress myeloid differentiation allowing for proper megakaryocyte development. LSD1 inhibitor and GFI1BQ287*-mediated perturbation of this function causes myeloid skewing during megakaryocyte development.
2024-03-28 | GSE244756 | GEO
Project description:Mutations in transcription factor Growth Factor Independence 1B (GFI1B) cause inherited bleedings with varying intensity possibly caused by different effects on the transcriptional function of GFI1B. We studied transcriptomic changes of normal and GFI1BT174N,H181Y,R184P,Q287* mutants in megakaryoblast MEG01 cells using RNA-sequencing. Compared to normal GFI1B each variant affected different gene modules with limited overlap between variants. Remarkably, GFI1BQ287* specifically activated a myeloid-associated gene module. Based on this finding we studied megakaryocyte differentiation using normal and GFI1BQ287* patient-derived induced pluripotent stem cells (IPSC) followed by single cell RNA-sequencing. This revealed a 45-fold decrease in the megakaryocyte/myeloid cell ratio in the GFI1BQ287* versus control condition. Moreover, myeloid specific genes were expressed within GFI1BQ287* but not normal megakaryocytes. Finally, we studied how megakaryocyte development was affected by inhibiting binding of GFI1B to Lysine Specific Demethylase 1 (LSD1), an interaction required for megakaryocyte development. Treatment of both MEG01 cells and normal IPSC-derived developing megakaryocytes with the small-molecule inhibitor GSK-LSD1 resulted in profound activation of myeloid gene programs within megakaryocytes, while the IPSC-derived megakaryocyte/myeloid ratio dropped two-fold. We conclude that GFI1B and LSD1 suppress myeloid differentiation allowing for proper megakaryocyte development. LSD1 inhibitor and GFI1BQ287*-mediated perturbation of this function causes myeloid skewing during megakaryocyte development.
2024-03-28 | GSE244609 | GEO
Project description:Effect of GFI1B ectopic expression in the hematopoietic or endothelial commitment of human iPSC derived CD34+CD43-CD73- hemogenic endothelium (HE)
| PRJNA1032643 | ENA
Project description:Hematopoietic stem cells (HSCs) are generated via a natural transdifferentiation process known as endothelial-to-hematopoietic cell transition (EHT). Due to small numbers of embryonal arterial cells undergoing EHT and the paucity of markers to enrich for hemogenic endothelial cells, the genetic program driving HSC emergence is largely unknown. Here, we use a highly sensitive RNAseq method to examine the whole transcriptome of small numbers of enriched aortic HSCs (CD31+cKit+Ly6aGFP+), hemogenic endothelial cells (CD31+cKit-Ly6aGFP+) and endothelial cells (CD31+cKit-Ly6aGFP-). Comparison of mRNA profiles of endothelial cells, hemogenic endothelial cells, and hematopoietic stem cells generated by deep-sequencing of sorted populations from pool of embryos, in triplicate.
2014-12-14 | E-GEOD-63316 | biostudies-arrayexpress
Project description:During development, hematopoietic stem/progenitor cells (HSPCs) arise from specialized endothelial cells by a process termed endothelial-to-hematopoietic transition (EHT). The genetic program driving human HSPC emergence remains largely unknown. We previously reported that the generation of hemogenic precursor cells from mouse fibroblasts recapitulates developmental hematopoiesis. Here, we demonstrate that human fibroblasts can be reprogrammed into hemogenic cells by the same transcription factors. Induced cells display dynamic EHT transcriptional programs, generate hematopoietic progeny, possess HSPC cell surface phenotype and repopulate immunodeficient mice for three months. Mechanistically, GATA2 and GFI1B interact and co-occupy a cohort of targets. This cooperative binding is reflected by engagement of open enhancers and promoters, initiating silencing of fibroblast genes and activating the hemogenic program. However, GATA2 displays dominant and independent targeting activity during the early phases of reprogramming. These findings shed light on the processes controlling human HSC specification and support generation of reprogrammed HSCs for clinical applications.
2018-12-04 | GSE51025 | GEO
Project description:Transcription factor GFI1B suppresses its own gene expression, and deregulated GFI1B expression contributes to myeloid neoplasms. The DNA polymorphism rs621940 located 8 kb downstream of GFI1B predisposes for clonal hematopoiesis and myeloproliferative neoplasms. Whether rs621940 affects GFI1B expression is unknown. We observed clear GFI1B binding around the rs621940 locus in megakaryoblast MEG-01 cells using ChIP-seq. Pull-downs using DNA-sequences with either rs621940-allele followed by protein identification using mass spectrometry detected 24 differentially bound proteins in MEG-01 cells, but GFI1B was not among these. Also, GFI1B auto-repression was not different between either rs621940-allele in transient gene reporter assays. Deletion of an 1.6 kb fragment encompassing rs621940 in K562 cells did not alter GFI1B expression nor GFI1B auto-repression. In primary peripheral blood mononuclear cells from healthy donors, absolute GFI1B expression did not differ consistently between the rs621940 alleles. Finally, GFI1B haplotyping using long range DNA sequencing detected 3’ non-coding polymorphisms on the same chromosome as the rs621940 polymorphism. Yet, targeted deep RNA sequencing did not detect consistent effects of rs621940 on allelic GFI1B expression. These studies find no evidence that rs621940 affects GFI1B expression nor GFI1B auto-repression.
2022-01-02 | GSE125246 | GEO