Project description:β-thalassemia cell lines were generated via CRISPR-Cas9 genome editing of Bristol Erythroid Line Adult (BEL-A) and differentiated to the basophilic and polychromatic erythroid cell stage. TMT comparative proteomics was then performed on stage matched WT and β-thalassemia cells isolated by FACS.
Project description:Terminal differentiation of mammalian erythroid progenitors involves 4-5 cell divisions and induction of many erythroid important genes, followed by chromatin and nuclear condensation and enucleation. The protein levels of c-myc (Myc) are reduced dramatically during late stage erythroid maturation, coinciding with cell cycle arrest in G1-phase and enucleation, suggesting possible roles for c-myc in either or both of these processes. Here we demonstrate that ectopic Myc expression affects terminal erythroid maturation in a dose-dependent manner. Expression of Myc at physiological levels did not affect erythroid differentiation or cell cycle shutdown, but specifically blocked erythroid nuclear condensation and enucleation. Myc prevented deacetylation of several lysine residues in histones H3 and H4 that are normally deacetylated during erythroid maturation. When over-expressed at levels higher than the physiological range, Myc blocked erythroid differentiation and the cells continued to proliferate in cytokine-free, serum-containing culture medium with an early erythroblast morphology. These studies reveal an important dose-dependent function of Myc in regulating terminal maturation in mammalian erythroid cells. Our findings further support the emerging notion that Myc regulates chromatin structure by regulating global histone acetylation states. Five groups with three biological replicates in each.
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:Burst-forming unit-erythroid (BFU-E) and colony-forming unit-erythroid (CFU-E) cells are erythroid progenitors traditionally defined by colony assays. We developed a flow cytometry-based strategy for isolating human BFU-E and CFU-E cells based on the changes in expression of cell surface markers during in vitro erythroid cell culture. BFU-E and CFU-E are characterized by CD45+GPA-IL-3R-CD34+CD36-CD71low and CD45+GPA-IL-3R-CD34-CD36+CD71high phenotypes, respectively. Colony assays validated phenotypic assignment giving rise to BFU-E and CFU-E colonies, both at a purity ~90%. The BFU-E colony forming ability of CD45+GPA-IL-3R-CD34+CD36-CD71low cells required SCF and erythropoietin, while the CFU-E colony forming ability of CD45+GPA-IL-3R-CD34-CD36+CD71high cells required only erythropoietin. Bioinformatic analysis of the RNA-seq data revealed unique transcriptomes in each differentiation stage. The sorting strategy was validated in uncultured primary cells isolated from bone marrow and peripheral blood, indicating that marker expression is not an artifact of in vitro cell culture, but represents an in vivo characteristic of erythroid progenitor populations. The ability to isolate highly pure human BFU-E and CFU-E progenitors will enable detailed cellular and molecular characterization of these distinct progenitor populations and define their contribution to disordered erythropoiesis in inherited and acquired hematological disease. Our data provide important resource for future studies. Transcription profiles of Human erythroid progenitors at distinct developmental stages were generated by deep sequencing, in triplicate, using IlluminaHiSeq 2000. The complete dataset comprises 4 sample types: CD34, BFU, CFU, and Pro (reanalysis of GSM1304777-GSM1304779).
Project description:The chromatin modifying enzymes that drive the erythroid-specific transcription program are incompletely understood. Setd8 is the sole histone methyltransferase in mammals capable of generating mono-methylated histone H4 lysine 20 (H4K20me1) and is expressed at significantly higher levels in erythroid cells than any other cell- or tissue- type, suggesting that Setd8 has an erythroid-specific function. To test this hypothesis, stable knockdown of Setd8 was established in extensively self-renewing erythroblasts (ESREs), a well-characterized, non-transformed, model of erythroid maturation. Setd8 knockdown impaired erythroid maturation, characterized by a delay in hemoglobin accumulation, larger cell area, persistent kit expression, incomplete nuclear condensation, and lower rates of enucleation than control cells. Setd8 knockdown did not alter ESRE proliferation or viability, or result in accumulation of DNA damage. Global gene expression analyses following Setd8 knockdown suggests that in erythroid cells, Setd8 functions primarily as a repressor and demonstrated high levels of Gata2 expression. Setd8 occupies critical regulatory elements in the Gata2 locus, and knockdown of Setd8 resulted in loss of H4K20me1 and gain of H4 acetylation at the Gata2 1S promoter. Taken together, these results imply that Setd8 is an important regulator of erythroid maturation that works in part through repression of Gata2. RNA-seq was performed of Setd8 knockdown and control cells, both while the cells were proliferating, and after 6 hours of maturation.
Project description:The aim of the study is to develop a scalable continuous agitation suspension culture bioprocess for differentiation of hiPSCs towards erythroid cells. Using process optimization, we developed the entire process completely in agitation suspension culture condition starting from hiPSC expansion through to hematopoietic induction and erythroid differentiation. Transcriptome profiling was carried out to facilitate comparisons between erythroid cells differentiated from hiPSCs using this bioprocess, and erythroid cells differentiated from cord blood and adult CD34+ cells.
Project description:Terminal differentiation of mammalian erythroid progenitors involves 4-5 cell divisions and induction of many erythroid important genes, followed by chromatin and nuclear condensation and enucleation. The protein levels of c-myc (Myc) are reduced dramatically during late stage erythroid maturation, coinciding with cell cycle arrest in G1-phase and enucleation, suggesting possible roles for c-myc in either or both of these processes. Here we demonstrate that ectopic Myc expression affects terminal erythroid maturation in a dose-dependent manner. Expression of Myc at physiological levels did not affect erythroid differentiation or cell cycle shutdown, but specifically blocked erythroid nuclear condensation and enucleation. Myc prevented deacetylation of several lysine residues in histones H3 and H4 that are normally deacetylated during erythroid maturation. When over-expressed at levels higher than the physiological range, Myc blocked erythroid differentiation and the cells continued to proliferate in cytokine-free, serum-containing culture medium with an early erythroblast morphology. These studies reveal an important dose-dependent function of Myc in regulating terminal maturation in mammalian erythroid cells. Our findings further support the emerging notion that Myc regulates chromatin structure by regulating global histone acetylation states.
Project description:Analysis of gene expression in Mouse Ter119+ erythroid cells Paired end RNA-seq analysis of PolyA selected RNA from Mouse Ter119+ erythroid cells