ABSTRACT: This SuperSeries is composed of the following subset Series: GSE20544: TAL1 knock down in Jurkat cells GSE20545: TAL1 knock down in human erythroid progenitors Refer to individual Series
ORGANISM(S): Homo sapiens
SUBMITTER: OGIC Ontario Genomics Innovation Centre (OGIC)
Project description:We used microarray profiling in erythroid cells to uncover TAL1 dependent genes in a hematopoietic differentiation context. Differentiated ex vivo hematopoietic multipotential progenitors isolated from adult peripheral blood. The knockdown of TAL1 (KD) was induced in pro-erythroblasts (Days 8 and 9 of differentiation) using lentivirus-delivered shRNA. A scramble (scr) shRNA sequence was used as a negative control.
Project description:Signaling through the AKT and ERK pathways controls cell proliferation. However, the integrated regulation of this multistep process, involving signal processing, cell growth and cell-cycle progression, is poorly understood. Here we study different murine hematopoietic cell types, in which AKT and ERK signaling is triggered by erythropoietin (Epo). Although these cell types share the molecular network topology for pro-proliferative Epo signaling, they exhibit distinct proliferative responses. Iterating quantitative experiments and mathematical modeling, we identify two molecular sources for cell-type-specific proliferation. First, cell-type-specific protein abundance patterns cause differential signal flow along the AKT and ERK pathways. Second, downstream regulators of both pathways have differential effects on proliferation, suggesting that protein synthesis is rate-limiting for faster-cycling cells while slower cell-cycles are controlled at the G1-S progression. The integrated mathematical model of Epo-driven proliferation explains cell-type-specific effects of targeted AKT and ERK inhibitors and faithfully predicts based on the protein abundance anti-proliferative effects of inhibitors in primary human erythroid progenitor cells. Our findings suggest that the effectiveness of targeted cancer therapy might become predictable from protein abundance patterns.
Project description:We derived B-lineage cells by in vitro culture of neonatal cord blood CD34+ cells on MS-5 stromal cells with recombinant IL-7. These cultures yielded CD19+CD127+ and CD19+CD127- cell populations. We performed gene expression profiling on these populations and compared these with each other and with published expression profiles of freshly isolated BM precursor B-cell subsets (E-MEXP-384). These analyses yielded new insights into their different functionality and developmental stage.<br><br>A file containing statistical analysis of the normalized data is included in the file named E-MEXP-2878.additional.zip on the FTP site for this experiment.
Project description:Developmental and homeostatic remodeling of cellular organelles is mediated by a complex process termed autophagy. The cohort of proteins that constitute the autophagy machinery function in a multistep biochemical pathway. Though components of the autophagy machinery are broadly expressed, autophagy can occur in specialized cellular contexts, and mechanisms underlying cell type-specific autophagy are poorly understood. We demonstrate that the master regulator of hematopoiesis GATA-1 directly activates transcription of genes encoding the essential autophagy component Microtubule Associated Protein 1 Light Chain 3B (LC3B) and its homologs (MAP1LC3A, GABARAP, GABARAPL1, GATE-16). In addition, GATA-1 directly activates genes involved in the biogenesis/function of lysosomes, which mediate autophagic protein turnover. We demonstrate that GATA-1 utilizes the forkhead protein FoxO3 to activate select autophagy genes. GATA-1-dependent LC3B induction is tightly coupled to accumulation of the active form of LC3B and autophagosomes, which mediate mitochondrial clearance as a critical step in erythropoiesis. These results illustrate a novel mechanism by which a master regulator of development establishes a genetic network to instigate cell type-specific autophagy. Genome-wide maps of GATA1 factor occupancy in primary human PBMC derived erythroblasts
Project description:Homing and engraftment of hematopoietic stem cells (HSCs) to the bone marrow (BM) involve a complex interplay between chemokines, cytokines, and non-peptide molecules. Extracellular nucleotides and their cognate P2 receptors are emerging as key-factors of inflammation and related chemotactic responses. In this study, we investigated the activity of extracellular adenosine-triphosphate (ATP) and uridine-triphosphate (UTP) on CXCL12-stimulated CD34+ HSC chemotaxis. In vitro, UTP significantly improved HSC migration, inhibited cell membrane CXCR4 down-regulation of migrating CD34+ cells and increased cell adhesion to fibronectin. In vivo, pre-incubation with UTP significantly enhanced the BM homing efficiency of human CD34+ cells in immunodeficient mice. Pertussis toxin blocked CXCL12- and UTP-dependent chemotactic responses, suggesting that G-protein alpha-subunits (Gαi) may provide a converging signal for CXCR4- and P2Y-activated transduction pathways. In addition, gene expression profiling of UTP-treated CD34+ cells and in vitro inhibition assays demonstrated that Rho guanosine 5â-triphosphatases (GTPase) Rac2 and downstream effectors Rho GTPaseâactivated kinases 1 and 2 (ROCK1/2) are involved in UTP-promoted/CXCL12-dependent HSC migration. Our data suggest that UTP may physiologically modulate the migration of HSCs and their homing to the BM, in concert with CXCL12, via the activation of converging signaling pathways between CXCR4 and P2Y receptors, involving Gαi proteins and RhoGTPases. Experiment Overall Design: Highly purified CD34+ cells from 6 healthy donors were seeded at 1000000 cells/ml in serum free medium (EX vivo 15) w/o cytokines and treated with 10 mM UTP, 150ng/ml CXCL12, or 10 mM UTP plus 150ng/ml CXCL12 respectively for 24 hours. As a control, CD34+ untreated cells were maintained in the same culture conditions at the same time.
Project description:Gene expression profiling was performed on primary human erythroid progenitor cells left untreated or treated with 2uM NK57 for 3 days. The worldwide burden of sickle cell disease is enormous, with over 200,000 infants born with the disease each year in Africa alone. Induction of fetal hemoglobin is a validated strategy to improve symptoms and complications of this disease. The development of targeted therapies has been limited by the absence of discrete druggable targets. We developed a novel bead-based strategy for the identification of inducers of fetal hemoglobin transcripts in primary human erythroid cells. A small-molecule screen of bioactive compounds identified remarkable class-associated activity among histone deacetylase (HDAC) inhibitors. Using a chemical genetic strategy combining focused libraries of biased chemical probes and reverse genetics by RNA interference, we have identified HDAC1 and HDAC2 as molecular targets mediating fetal hemoglobin induction. Our findings suggest the potential of isoform-selective inhibitors of HDAC1 and HDAC2 for the treatment of sickle cell disease. Gene expression profiling was performed on primary human erythroid progenitor cells left untreated (n=7) or treated with 2uM NK57 for 3 days (n=2).
Project description:Global, genomic responses of erythrocytes to infectious agents have been difficult to measure, because these cells are e-nucleated. We have previously demonstrated that in vitro matured, nucleated erythroblast cells at the orthochromatic stage can be efficiently infected by the human malaria parasite Plasmodium falciparum. We now show that infection of orthochromatic cells induces change in 609 host genes. 592 of these transcripts are up-regulated and associated with metabolic and chaperone pathways unique to P. falciparum infection, as well as a wide range of signaling pathways that are also induced in related apicomplexan infections of mouse hepatocytes or human fibroblast cells. Our data additionally show that polychromatophilic cells, which precede the orthochromatic stage and are not infected when co-cultured with P. falciparum, up-regulate a small set of 35 genes, 9 of which are associated with pathways of hematopoiesis and/or erythroid cell development. These data unexpectedly predict that blood stage P. falciparum may induce host responses common to infections of other pathogens. Further P. falciparum may modulate gene expression in bystander erythroblasts and thus influence pathways of erythrocyte development. Human primary erythroid cells were differentiated from CD34+ hematopoietic stem cells isolated from growth factor-mobilized peripheral blood (ALL Cells, Inc.). Cells from five donors were cultured until polychromatophilic and orthochromatophilic stages of differentiation and served as uninfected control samples. Of the five donors, three were used to initiate Plasmodium falciparum (3D7) infection at a multiplicity of infection = 5. Infected cells were harvested 24 hours post-infection, and RNA was isolated with Trizol (Invitrogen) and purified with RNeasy columns (QIAGEN) according to manufacturer recommendations. Microarray labeling and hybridizations were done according to Affymetrix protocols using HG U133 plus 2.0 chips. For GenePattern analysis, all samples (5 control and 3 infected samples) were analyzed; for Dchip analysis, only three samples were analyzed (the same 3 donors served as control and infected samples).
Project description:Gene expression profiling was performed on primary human erythroid progenitor cells expressing a control shRNA (luciferase), two different HDAC1 shRNAs, and two different HDAC2 shRNAs. The worldwide burden of sickle cell disease is enormous, with over 200,000 infants born with the disease each year in Africa alone. Induction of fetal hemoglobin is a validated strategy to improve symptoms and complications of this disease. The development of targeted therapies has been limited by the absence of discrete druggable targets. We developed a novel bead-based strategy for the identification of inducers of fetal hemoglobin transcripts in primary human erythroid cells. A small-molecule screen of bioactive compounds identified remarkable class-associated activity among histone deacetylase (HDAC) inhibitors. Using a chemical genetic strategy combining focused libraries of biased chemical probes and reverse genetics by RNA interference, we have identified HDAC1 and HDAC2 as molecular targets mediating fetal hemoglobin induction. Our findings suggest the potential of isoform-selective inhibitors of HDAC1 and HDAC2 for the treatment of sickle cell disease. Gene expression profiling was performed on primary human erythroid progenitor cells expressing a control shRNA (luciferase, n=3), two different HDAC1 shRNAs (n=2 and n=3), and two different HDAC2 shRNAs (n=3 for each).