To study the underlying molecular mechanisms causing the defect in megakaryocyte development by FLI1 p.Met100*
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE291026 | GEO | 2026/01/14
REPOSITORIES: GEO
Similar Datasets
Project description:Megakaryocytes and platelets arise from hematopoietic stem and progenitor cells through a tightly regulated process involving various transcription factors, including ETS family member FLI1. Pathogenic variants in FLI1, particularly those affecting the ETS DNA-binding domain, have been implicated in inherited thrombocytopenia and are associated with abnormal giant alpha granules, as seen in Paris-Trousseau Syndrome. However, the precise pathophysiological mechanisms remain unclear. Here, we describe a patient with a de novo heterozygous nonsense mutation, FLI1Met100* (c.297del), and investigate its effects on megakaryopoiesis using the Meg01 megakaryoblast cell line as a model. We hypothesized that this variant generates a truncated protein that exerts a dominant-negative effect on megakaryocyte maturation. Western blot analysis confirmed the presence of the truncated protein following FLI1Met100* overexpression in Meg01 cells. To further examine its impact, we overexpressed both wild-type FLI1 (FLI1WT) and FLI1Met100* in Meg01 cells, followed by bulk RNA sequencing and proteomics analysis. Gene set enrichment analysis revealed that FLI1WT enhanced megakaryocytic phenotypes while suppressing erythroid phenotypes, whereas FLI1Met100* upregulated both. Flow cytometry further confirmed that erythroid markers CD235a, CD36, and KLF1 were downregulated by FLI1WT but elevated by FLI1Met100*. Additionally, FLI1WT promoted megakaryocyte maturation and adhesion, as evidenced by increased expression of the megakaryocyte marker CD61 and adhesion markers CD34 and CD44. Moreover, we demonstrated through immunoprecipitation that both FLI1WT and FLI1Met100* interact with shared cofactors. Collectively, our findings suggest that FLI1Met100* impairs megakaryocyte maturation through a dominant-negative manner, potentially contributing to thrombocytopenia by promoting erythroid features at the expense of proper megakaryocytic development.
2025-12-05 | PXD063984 | Pride
Project description:In this study, we explored the function of the transcription factor ETV6 in megakaryopoiesis and assessed the impact of the pathogenic variant ETV6 p.R369W on megakaryocyte and platelet development. We hypothesized that ETV6 p.R369W acts in a dominant-negative manner, mimicking the molecular consequences of ETV6 deficiency. To investigate this, we overexpressed both wild-type ETV6 and the ETV6 p.R369W variant in Meg01 cells. Transcriptomic analysis revealed that ETV6 p.R369W upregulated genes associated with hematopoietic progenitor states and platelet activation, closely resembling the gene expression changes observed in ETV6 knockout cells.
2025-12-31 | GSE306384 | GEO
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:To study the underlying molecular mechanisms causing the defect in megakaryocyte development by FLI1 p.Met100*
| PRJNA1231424 | ENA
Project description:Germline variations in FLI1, essential for megakaryopoiesis, are linked to bleeding disorders, platelet aggregation defects and mild thrombocytopenia. However, the mechanisms behind these abnormalities remain unclear. This study aims to elucidate the impact of FLI1 variants on human megakaryocytes and platelets.
2025-03-31 | GSE273210 | GEO
Project description:Despite our growing understanding of embryonic immune development, rare early megakaryocytes (MKs) remain relatively understudied. Here we used single-cell RNA sequencing of human MKs from embryonic yolk sac (YS) and fetal liver (FL) to characterize the transcriptome, cellular heterogeneity, and developmental trajectories of early megakaryopoiesis. In the YS and FL, we found heterogeneous MK subpopulations with distinct developmental routes and patterns of gene expression that could reflect early functional specialization. Intriguingly, we identified a subpopulation of CD42b+CD14+ MKs in vivo that exhibit high expression of genes associated with immune responses and can also be derived from human embryonic stem cells (hESCs) in vitro. Furthermore, we identified THBS1 as an early marker for MK-biased embryonic endothelial cells. Overall, we provide important insights and invaluable resources for dissection of the molecular and cellular programs underlying early human megakaryopoiesis.
2020-12-21 | GSE144024 | GEO
Project description:MicroRNAs are small non-coding RNAs that regulate cellular development by interfering with mRNA stability and translation. We defined the kinetics of global microRNA expression during the differentiation of murine hematopoietic progenitors into megakaryocytes. Of 435 miRNAs analyzed, 13 were upregulated and 81 were downregulated. Many of these changes are consistent with miRNA profiling studies of human megakaryocytes and platelets, although new patterns also emerged. Among 7 conserved miRNAs that were upregulated most strongly in megakaryocytes, 6 were also induced in the related erythroid lineage. MiR-146a was strongly upregulated during mouse and human megakaryopoiesis, but not erythropoiesis. However, overexpression of miR-146a in mouse bone marrow hematopoietic progenitor populations produced no detectable alterations in megakaryocyte development or platelet production in vivo or in colony assays. Our findings extend the repertoire of differentially regulated miRNAs during murine megakaryopoiesis and provide a useful new dataset for hematopoiesis research. In addition, we show that enforced hematopoietic expression of miR-146a has minimal effects on megakaryopoiesis. These results are compatible with prior studies indicating that miR-146a inhibits megakaryocyte production indirectly by suppressing cytokine production from innate immune cells, but cast doubt on a different study, which suggests that this miRNA inhibits megakaryopoiesis cell-autonomously.
2010-12-07 | GSE22480 | GEO
Project description:MicroRNAs are small non-coding RNAs that regulate cellular development by interfering with mRNA stability and translation. We defined the kinetics of global microRNA expression during the differentiation of murine hematopoietic progenitors into megakaryocytes. Of 435 miRNAs analyzed, 13 were upregulated and 81 were downregulated. Many of these changes are consistent with miRNA profiling studies of human megakaryocytes and platelets, although new patterns also emerged. Among 7 conserved miRNAs that were upregulated most strongly in megakaryocytes, 6 were also induced in the related erythroid lineage. MiR-146a was strongly upregulated during mouse and human megakaryopoiesis, but not erythropoiesis. However, overexpression of miR-146a in mouse bone marrow hematopoietic progenitor populations produced no detectable alterations in megakaryocyte development or platelet production in vivo or in colony assays. Our findings extend the repertoire of differentially regulated miRNAs during murine megakaryopoiesis and provide a useful new dataset for hematopoiesis research. In addition, we show that enforced hematopoietic expression of miR-146a has minimal effects on megakaryopoiesis. These results are compatible with prior studies indicating that miR-146a inhibits megakaryocyte production indirectly by suppressing cytokine production from innate immune cells, but cast doubt on a different study, which suggests that this miRNA inhibits megakaryopoiesis cell-autonomously. Exiqon locked nucleic acid (LNA) microarrays were used to compare microRNA expression in starting populations (ter 119- progenitors) and purified megakaryocytes. Day13.5-14.5 murine fetal livers (strain CD1) were depleted of erythroid cells and cultured with thrombopoietin to generate megakaryocytes. Each total RNA sample (0.5 μg per reaction) was labeled with Hy3 and Hy5 dyes using the Exiqon Power Labeling Kit and automated microarray hybridizations and washes were performed on a Tecan HS4800 station with 20 hr hybridization at 56ºC. Dye-swap pairs of three replicate experiments comparing Ter119- fetal liver cells vs. BSA-purified megakaryocytes were co-hybridized to six arrays. The geometric average of the 532 and 635 measurements after normalization was determined for each sample.
2010-12-07 | E-GEOD-22480 | biostudies-arrayexpress
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:Megakaryocyte is the naturally polyploid cell that gives rise to platelets. Polyploidization occurs by endomitosis, a process corresponding to a late failure of cytokinesis with a backward movement of the daughter cells. Generally, a pure defect in cytokinesis produces a multinucleated cell, but megakaryocytes are characterized by a single polylobulated nucleus with a 2 (N) ploidy. Here, we show the existence of a defect in karyokinesis during the endomitotic process. From late telophase until the reversal of cytokinesis, some dipolar mitosis/endomitosis and most multipolar endomitosis present a thin DNA link between the segregated chromosomes surrounded by an incomplete nuclear membrane formation, which implies that sister chromatid separation is not complete. This observation may explain why polyploid megakaryocytes display a single polylobulated nucleus along with an increase in ploidy.
| S-EPMC3552921 | biostudies-literature