Project description:Thioredoxin-interacting protein (TXNIP) is ubiquitously expressed in blood cells, including hematopoietic stem cells (HSCs), monocytes, and platelets. Here we report a novel finding that TXNIP plays a crucial role in megakaryopoiesis and platelet biogenesis via interacting with GATA1, a transcription factor for megakaryocyte-erythroid differentiation. Txnip-/- mice displayed immature megakaryocytes in the bone marrow with thrombocytopenia, which had gotten worse as the mice aged. Transcriptome analysis revealed that the transcriptional activity of GATA1 was significantly enhanced in the Txnip-/- megakaryocyte precursors (MkPs) than wild type (WT) cells. During megakaryopoiesis in ex vivo, Txnip-/- MkPs remained small in cell size with less mitochondrial mass, and more glycolysis for ATP production, as opposed to the normal megakaryocyte maturation. The effects of TXNIP in megakaryocytes were recapitulated in human cord blood CD34+ HSC-derived differentiation. Taken together, this study demonstrates the importance of spatiotemporal expression of TXNIP in platelet biogenesis. We propose for the first time that TXNIP might play a critical role in determining a lineage between megakaryocytes and erythroid cells from a common megakaryocyte-erythroid progenitor via regulation of transcriptional activity of GATA1.
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.
Project description:Background: Recent advances in single-cell techniques have provided the opportunity to finely dissect cellular heterogeneity within populations previously defined by “bulk” assays and to uncover rare cell types. In human hematopoiesis, megakaryocytes and erythroid cells differentiate from a shared precursor, the megakaryocyte-erythroid progenitor (MEP), which remains poorly defined.Results: To clarify the cellular pathway in erythro-megakaryocyte differentiation, we correlated the surface immunophenotype, transcriptional profile and differentiation potential of individual MEP cells. Highly purified, single MEP cells (n=681) were analyzed using index fluorescence-activated cell sorting with parallel targeted transcriptional profiling of the same cells performed using a specifically designed panel of 87 genes. Differentiation potential was tested in novel, single-cell differentiation assays. Our results demonstrated that immunophenotypic MEP in fact comprise three distinct subpopulations: (1) “Pre-MEP”, enriched for erythroid/megakaryocyte progenitors but with residual myeloid differentiation capacity (2) “E-MEP”, strongly biased towards erythroid differentiation, and (3) “MK-MEP”, a previously undescribed, rare population of cells that are bipotent but primarily generate megakaryocytic progeny. Therefore, conventionally-defined MEP are in fact a mixed population: a minority give rise to mixed-lineage colonies while the majority of cells are transcriptionally-primed to generate exclusively single-lineage output. Conclusions: Our study clarifies the cellular hierarchy in human megakaryocyte/erythroid lineage commitment and highlights the importance of using a combination of single-cell approaches to dissect cellular heterogeneity and identify rare cell types within a population. We present a novel immunophenotyping strategy that enables the prospective identification of specific intermediate progenitor populations in erythro-megakaryopoiesis, allowing for in-depth study of disorders including inherited cytopenias, myeloproliferative disorders and erythromegakaryocytic leukemias.
Project description:Background: Recent advances in single-cell techniques have provided the opportunity to finely dissect cellular heterogeneity within populations previously defined by âbulkâ assays and to uncover rare cell types. In human hematopoiesis, megakaryocytes and erythroid cells differentiate from a shared precursor, the megakaryocyte-erythroid progenitor (MEP), which remains poorly defined.Results: To clarify the cellular pathway in erythro-megakaryocyte differentiation, we correlated the surface immunophenotype, transcriptional profile and differentiation potential of individual MEP cells. Highly purified, single MEP cells (n=681) were analyzed using index fluorescence-activated cell sorting with parallel targeted transcriptional profiling of the same cells performed using a specifically designed panel of 87 genes. Differentiation potential was tested in novel, single-cell differentiation assays. Our results demonstrated that immunophenotypic MEP in fact comprise three distinct subpopulations: (1) âPre-MEPâ, enriched for erythroid/megakaryocyte progenitors but with residual myeloid differentiation capacity (2) âE-MEPâ, strongly biased towards erythroid differentiation, and (3) âMK-MEPâ, a previously undescribed, rare population of cells that are bipotent but primarily generate megakaryocytic progeny. Therefore, conventionally-defined MEP are in fact a mixed population: a minority give rise to mixed-lineage colonies while the majority of cells are transcriptionally-primed to generate exclusively single-lineage output. Conclusions: Our study clarifies the cellular hierarchy in human megakaryocyte/erythroid lineage commitment and highlights the importance of using a combination of single-cell approaches to dissect cellular heterogeneity and identify rare cell types within a population. We present a novel immunophenotyping strategy that enables the prospective identification of specific intermediate progenitor populations in erythro-megakaryopoiesis, allowing for in-depth study of disorders including inherited cytopenias, myeloproliferative disorders and erythromegakaryocytic leukemias. Multiplex RT-PCR gene expression profiling of 807 human megakaryocyte-erythroid progenitor cells (MEP) isolated from three healthy donors by apheresis following G-CSF treatment. Cells were excluded if more than 70 assays did not result in amplification or displayed Ct higer than 13 for B2M or higher than 15 for GAPDH. Furthermore cells with a mean non-dropout Ct value greater than 20 were removed. This resulted in a dataset of 681 cells, which were subsequently normalised to the mean of B2M and GAPDH expression.
Project description:This SuperSeries is composed of the SubSeries listed below. Germline GATA1 mutations resulting in the production of an amino-truncated protein termed GATA1s (for M-bM-^@M-^\shortM-bM-^@M-^]) cause congenital hypoplastic anemia. Similar somatic mutations promote transient myeloproliferative disease and acute megakaryoblastic leukemia in trisomy 21 patients. Here we show that induced pluripotent stem cells (iPSCs) from patients with GATA1-truncating mutations exhibit impaired erythroid potential but enhanced megakaryopoiesis and myelopoiesis, faithfully recapitulating the major phenotypes of associated diseases. Similarly, GATA1s promotes megakaryopoiesis but not erythropoiesis in developmentally arrested Gata1- murine megakaryocyte-erythroid progenitors derived from murine embryonic stem cells (ESCs). Transcriptome studies demonstrate a selective deficiency in the ability of GATA1s to activate erythroid-expressed genes within populations of hematopoietic progenitors. Although its DNA binding domain is intact, chromatin immunoprecipitation studies show that GATA1s binding at specific erythroid regulatory regions is impaired, while binding at many non-erythroid sites, including megakaryocytic and myeloid target genes, is normal. These observations point to lineage specific GATA1 co-factor associations essential for normal chromatin occupancy and provide mechanistic insights into how GATA1s mutations cause human disease. More broadly, our studies underscore the value of ESCs and iPSCs to recapitulate and study disease phenotypes. Refer to individual Series
Project description:This SuperSeries is composed of the SubSeries listed below. Germline GATA1 mutations resulting in the production of an amino-truncated protein termed GATA1s (for “short”) cause congenital hypoplastic anemia. Similar somatic mutations promote transient myeloproliferative disease and acute megakaryoblastic leukemia in trisomy 21 patients. Here we show that induced pluripotent stem cells (iPSCs) from patients with GATA1-truncating mutations exhibit impaired erythroid potential but enhanced megakaryopoiesis and myelopoiesis, faithfully recapitulating the major phenotypes of associated diseases. Similarly, GATA1s promotes megakaryopoiesis but not erythropoiesis in developmentally arrested Gata1- murine megakaryocyte-erythroid progenitors derived from murine embryonic stem cells (ESCs). Transcriptome studies demonstrate a selective deficiency in the ability of GATA1s to activate erythroid-expressed genes within populations of hematopoietic progenitors. Although its DNA binding domain is intact, chromatin immunoprecipitation studies show that GATA1s binding at specific erythroid regulatory regions is impaired, while binding at many non-erythroid sites, including megakaryocytic and myeloid target genes, is normal. These observations point to lineage specific GATA1 co-factor associations essential for normal chromatin occupancy and provide mechanistic insights into how GATA1s mutations cause human disease. More broadly, our studies underscore the value of ESCs and iPSCs to recapitulate and study disease phenotypes.
Project description:Long non-coding RNAs (lncRNAs) and miRNAs have emerged as crucial regulators of gene expression and cell fate decisions. Here we present an integrated analysis of the ncRNA-landscape of purified human hematopoietic stem cells (HSCs) and their differentiated progenies, including granulocytes, monocytes, T-cells, NK-cells, B-cells, megakaryocytes and erythroid precursors. For each blood cell population, RNA from 5 healthy donors was hybridized onto three microarray platforms (Arraystar lncRNA V2.0, NCode™-miRNA/-ncRNA), yielding a coverage of more than 40,000 lncRNAs, 25,000 mRNAs and 900 miRNAs on 146 arrays. T-distributed stochastic neighbor embedding (t-SNE) on noncoding genes structured the dataset into groups of samples that matched the input populations, demonstrating their unique lncRNA expression profiles. Self-organizing maps (SOMs) revealed clusters of lncRNAs and mRNAs that were coordinately expressed in HSCs and during lineage commitment. Using a “guilt-by-association” approach we assigned putative functions to lncRNAs regulated during differentiation, which predicted LINC00173 as a novel non-coding regulator of granulopoiesis. We knocked down LINC00173 using two independent shRNA constructs, which resulted in diminished granulocytic in vitro differentiation, myeloid colony-formation and function. Next, we uncovered a strong and highly coordinated upregulation of miRNAs, small nucleolar RNAs (snoRNAs) and lncRNAs within the DLK1-DIO3 locus on chromosome 14 (hsa14) during megakaryocytic maturation. shRNA-mediated knock-down of noncoding members of the locus reduced erythroid colony-formation and megakaryocytic cell proliferation in vitro implicating the functional importance of this ncRNA locus in megakaryopoiesis.
Project description:Long non-coding RNAs (lncRNAs) and miRNAs have emerged as crucial regulators of gene expression and cell fate decisions. Here we present an integrated analysis of the ncRNA-landscape of purified human hematopoietic stem cells (HSCs) and their differentiated progenies, including granulocytes, monocytes, T-cells, NK-cells, B-cells, megakaryocytes and erythroid precursors. For each blood cell population, RNA from 5 healthy donors was hybridized onto three microarray platforms (Arraystar lncRNA V2.0, NCode™-miRNA/-ncRNA), yielding a coverage of more than 40,000 lncRNAs, 25,000 mRNAs and 900 miRNAs on 146 arrays. T-distributed stochastic neighbor embedding (t-SNE) on noncoding genes structured the dataset into groups of samples that matched the input populations, demonstrating their unique lncRNA expression profiles. Self-organizing maps (SOMs) revealed clusters of lncRNAs and mRNAs that were coordinately expressed in HSCs and during lineage commitment. Using a “guilt-by-association” approach we assigned putative functions to lncRNAs regulated during differentiation, which predicted LINC00173 as a novel non-coding regulator of granulopoiesis. We knocked down LINC00173 using two independent shRNA constructs, which resulted in diminished granulocytic in vitro differentiation, myeloid colony-formation and function. Next, we uncovered a strong and highly coordinated upregulation of miRNAs, small nucleolar RNAs (snoRNAs) and lncRNAs within the DLK1-DIO3 locus on chromosome 14 (hsa14) during megakaryocytic maturation. shRNA-mediated knock-down of noncoding members of the locus reduced erythroid colony-formation and megakaryocytic cell proliferation in vitro implicating the functional importance of this ncRNA locus in megakaryopoiesis.
Project description:Long non-coding RNAs (lncRNAs) and miRNAs have emerged as crucial regulators of gene expression and cell fate decisions. Here we present an integrated analysis of the ncRNA-landscape of purified human hematopoietic stem cells (HSCs) and their differentiated progenies, including granulocytes, monocytes, T-cells, NK-cells, B-cells, megakaryocytes and erythroid precursors. For each blood cell population, RNA from 5 healthy donors was hybridized onto three microarray platforms (Arraystar lncRNA V2.0, NCode™-miRNA/-ncRNA), yielding a coverage of more than 40,000 lncRNAs, 25,000 mRNAs and 900 miRNAs on 146 arrays. T-distributed stochastic neighbor embedding (t-SNE) on noncoding genes structured the dataset into groups of samples that matched the input populations, demonstrating their unique lncRNA expression profiles. Self-organizing maps (SOMs) revealed clusters of lncRNAs and mRNAs that were coordinately expressed in HSCs and during lineage commitment. Using a “guilt-by-association” approach we assigned putative functions to lncRNAs regulated during differentiation, which predicted LINC00173 as a novel non-coding regulator of granulopoiesis. We knocked down LINC00173 using two independent shRNA constructs, which resulted in diminished granulocytic in vitro differentiation, myeloid colony-formation and function. Next, we uncovered a strong and highly coordinated upregulation of miRNAs, small nucleolar RNAs (snoRNAs) and lncRNAs within the DLK1-DIO3 locus on chromosome 14 (hsa14) during megakaryocytic maturation. shRNA-mediated knock-down of noncoding members of the locus reduced erythroid colony-formation and megakaryocytic cell proliferation in vitro implicating the functional importance of this ncRNA locus in megakaryopoiesis.
Project description:Embryonic stem (ES) and induced pluripotent stem (iPS) cells represent a potential source of megakaryocytes and platelets for transfusion therapies. However, most current ES/iPS cell differentiation protocols are limited by low yields of hematopoietic progeny. Mutations in the mouse and human genes encoding transcription factor GATA1 cause accumulation of proliferating, developmentally arrested megakaryocytes. To exploit this clinical observation, we engineered wildtype (WT) murine ES cells to express doxycycline (dox)-regulated Gata1 short hairpin (sh) RNAs. In vitro differentiation with dox and thrombopoietin (Tpo) resulted in approximately 1013-fold expansion of immature hematopoietic progenitors. Upon dox withdrawal with multilineage cytokines, GATA1 expression was restored and the cells differentiated into erythroblasts and megakaryocytes. With Tpo alone, dox-deprived progenitors formed mainly mature megakaryocytes that generated functional platelets in vivo. Our findings provide a novel, readily reproducible strategy to expand ES-cell derived megakaryocyte-erythroid progenitors and direct their differentiation into megakaryocytes producing functional platelets in clinically relevant numbers. 3 classes of samples were compared 1) fetal liver derived megkaryocytes 2) G1ME (Gata1â megakaryocyte-erythroid) 3) G1ME2 (engineered wildtype (WT) murine ES cells to express doxycycline (dox)-regulated Gata1 short hairpin (sh) RNAs)