Gene expression profiling in erythroid progenitors through ontogeny
ABSTRACT: Background: It has been reported that the phosphatidylinositol 3-kinase (PI3K)-AKT signaling pathway regulates erythropoietin (EPO)-induced survival, proliferation, and maturation of early erythroid progenitors. Erythroid cell proliferation and survival has also been related to activation of the JAK-STAT pathway. The goal of this study was to observe the function of EPO activation of JAK-STAT and PI3K/AKT pathways in the development of erythroid progenitors from hematopoietic CD34+ progenitor cells, as well as to distinguish early EPO target genes in human erythroid progenitors during ontogeny. Methods: Hematopoietic CD34+ progenitor cells, isolated from fetal and adult hematopoietic tissues, were differentiated into erythroid progenitor cells. We have used microarray analysis to examine JAK-STAT and PI3K/AKT related genes, as well as broad gene expression modulation in these human erythroid progenitor cells. Results: In microarray studies, a total of 1755 genes were expressed in fetal liver, 3844 in cord blood, 1770 in adult bone marrow, and 1325 genes in peripheral blood-derived erythroid progenitor cells. The erythroid progenitor cells shared 1011 common genes. Using the Ingenuity Pathways Analysis software, we evaluated the network pathways of genes linked to hematological system development, cellular growth and proliferation. The KITLG, EPO, GATA1, PIM1 and STAT3 genes represent the major connection points in the hematological system development linked genes. Some JAK-STAT signaling pathway-linked genes were steadily upregulated throughout ontogeny (PIM1, SOCS, MYC, PTPN11), while others were downregulated (PTPN6, PIAS, SPRED2). In addition, some JAK-STAT pathway related genes have specific expression just at certain stages of ontogeny (STATs, GRB2, CREBB). Beside continuously upregulated (AKT1, PPP2CA, CHUK, NFKB1) and downregulated (FOXO1, PDPK1, PIK3CG) genes in the PI3K-AKT signaling pathway, we also observed intermittently regulated gene expression (NFKBIA, YWHAH). Conclusions: This broad overview of gene expression in erythropoiesis revealed transcription factors with a prevalence at certain stages of ontogenesis. Finally, our results show that EPO-mediated proliferation and survival of erythroid progenitors occurs mainly through modulation of JAK-STAT pathway associated STATs, GRB2 and PIK3 genes, as well as AKT pathway- coupled NFKBIA and YWHAH genes. Adult peripheral blood mononuclear cells were isolated from buffy coats of 3 healthy donors using Lymphocyte Separation Medium (BioWhittaker, Walkersville, MD). We washed mononuclear cells twice with Dulbecco's phosphate-buffered saline (PBS, Invitrogen Corporation, Carlsbad, CA), and CD34+ cells were purified by positive immunomagnetic selection using the MACS cell isolation system (Miltenyi Biotec, Auburn, CA). Fresh bone marrow CD34+ cells were collected (AllCells LLC, Berkeley, CA). Cord blood CD34+ cells (AllCells LLC) and fetal liver CD34+ cells (Cambrex Bio Science, Inc., Walkersville, MD) were collected and frozen. For analysis, CD34+ cells were resuspended in medium, which contained 30% FBS, 2 mmol/L glutamine, 100 U/ml penicillin, 100 µg/ml streptomycin, 1% deionized BSA, 10 mmol/L beta-mercaptoethanol, 1 mmol/L dexamethasone, 33 µg/ml holo-transferrin, 10 ng/ml SCF, 1 ng/ml IL-3 and 1 ng/ml GM-CSF (Sigma, St. Louis, MO), and 1 U/ml human recombinant EPO (Amgen Inc, Thousand Oaks, CA) Erythroid progenitor cells differentiated from hematopoietic CD34+ progenitor cells of fetal liver, cord blood, bone marrow and peripheral blood origin Biological replicates: 2 fetal liver, 3 cord blood, 3 bone marrow, 3 peripheral blood origin
Project description:To investigate the effects of EDAG knockdown on gene exrpession profile in human cord blood CD34+ cells with EPO treatment with microarray assay. Freshly isolated human cord blood CD34+ cells were pre-activated for 24 hours and then infected with EDAG RNAi lentivirus or control lentivirus for 3 times within 24 hours. Then the cells were cultured in the presence of EPO to induce erythroid differentiation. Four days later, the cells were harvested for microarray test. The microarray showed that 3149 differentially expressed genes in siEDAG group compared to control group.The altered genes were associated with gene exrpression, cell cycle and hematopoietic differentiation. These data show that EDAG knckdown led to down-regulation of erythroid genes which are activated by GATA1. Human CD34+ cells infected with EDAG RNAi or control lentivirus were treated with EPO (5U/ml) for 4 days and gene expression were measured using Agilent human whole Genome 8*60K array. Two replicates.
Project description:Analysis of mobilized peripheral blood CD34+ cells from a healthy volunteer under erythroid differentiation conditions with and without stimulation to the BMP or Wnt signaling pathways. For erythroid differentiation, expanded CD34+ cells were placed in Stemspan SFEM medium supplemented with 2% pen/strep, 20ng/ml SCF, 1U/ml Epo, 5ng/ml IL3, 2uM dexamethasone, and 1uM beta-estradiol. Arrays were performed 2 hours after addition of cytokines. For signaling pathway stimulation, cells were exposed to 0.5uM BIO (a GSK3 inhibitor) for Wnt pathway activation, 25ng/ml rhBMP4 for BMP pathway activation, or vehicle control for 2 hours. Three biological replicates were performed per treatment group. We used microarrays to detail the global program of gene expression changes after Wnt or BMP pathway stimulation in human CD34+ hematopoietic progenitors under erythroid differentiation conditions. Overall design: To investigate the changes to gene expression in human CD34+ hematopoietic progenitors following stimulation of the Wnt or BMP pathways during the early stages of erythroid differentiation. Three biological replicates were performed per treatment group.
Project description:Analysis of mobilized peripheral blood CD34+ cells from a healthy volunteer under erythroid differentiation conditions with and without stimulation to the BMP or Wnt signaling pathways. For erythroid differentiation, expanded CD34+ cells were placed in Stemspan SFEM medium supplemented with 2% pen/strep, 20ng/ml SCF, 1U/ml Epo, 5ng/ml IL3, 2uM dexamethasone, and 1uM beta-estradiol. Arrays were performed 2 hours after addition of cytokines. For signaling pathway stimulation, cells were exposed to 0.5uM BIO (a GSK3 inhibitor) for Wnt pathway activation, 25ng/ml rhBMP4 for BMP pathway activation, or vehicle control for 2 hours. Three biological replicates were performed per treatment group. We used microarrays to detail the global program of gene expression changes after Wnt or BMP pathway stimulation in human CD34+ hematopoietic progenitors under erythroid differentiation conditions. To investigate the changes to gene expression in human CD34+ hematopoietic progenitors following stimulation of the Wnt or BMP pathways during the early stages of erythroid differentiation. Three biological replicates were performed per treatment group.
Project description:Myeloproliferative neoplasms (MPN) are clonal hematopoietic diseases that include essential thrombocytosis (ET), polycythemia vera (PV) and primary myelofibrosis (PMF) as well as BCR-ABL+ chronic myelogenous leukemia (CML). In the past several years, studies with cDNA microarrays have defined patterns of gene expression corresponding to specific molecular abnormalities, oncologic phenotypes, and clinical outcomes in hematologic malignancies. This study was aimed at the description of a gene expression signature in MPN which would eventually present a new pathogenetic approaching and also diagnostic as well as prognostic information. Using cDNA microarray analysis, involving 25,100 unique genes, we studied the gene expression profile of the pluripotent hematopoietic CD34+ stem cells and mature granulocytes obtained from peripheral blood of ET, PV, PMF and CML patients compared with healthy individuals. The average number of CD34+ cells (cells/µl) in peripheral blood was approximately 6 in PV and ET, 111 in PMF and 2880 in CML as measured by flow cytometry. A somatic point mutation JAK2V617F was detected in 93% of PV, 73% of PMF and 55% of ET patients within genetically homogenous population. The homozigosity for JAK2V617F mutation was the highest in PV (60%), less prominent in PMF (42%) and low in ET (11%) patients. The JAK2V617F mutation negative patients were also negative for exon 12 mutations. Approximately 420, 680 and 1130 genes had unique expression among CD34+ cells of ET, PV and PMF patients, respectively. In addition comparing to healthy controls, ET, PV, PMF and CML patients showed difference in 840, 1180, 1160 and 2050 expressed genes, respectively. Furthermore, we studied EPO and JAK-STAT signaling pathways related genes expression in MPN. The FOS, RAF1 and JAK2 gene expression, related to EPO signaling pathway, was elevated in ET, PV, PMF and reduced in CML comparing to healthy controls. Related to these genes, the JAK2V617F mutation homozygous and heterozygous patients generally displayed more significant differences comparing to patients with no mutation. STAT5 gene expression was decreased in all MPN patients. CSF3R, STAT1 and STAT3 gene expression, related to JAK-STAT signaling pathway, was elevated in ET, PV, PMF and reduced in CML comparing to healthy controls. CREBBP gene expression was reduced in CD34+ cells of ET, PV and PMF patients, but during maturation it enhanced expression in granulocytes. In conclusion, molecular profiling of CD34+ cells and granulocytes revealed a certain number of genes with changed expression that, beyond their recognized function in disease pathogenesis, can be related to patients’ clinical characteristics and may have an imminent prognostic relevance. Overall design: All study de novo patients were subjects to 30 ml of peripheral blood draw on one occasion, collected in 10% sodium citrate. The maximum time interval between venepuncture and arrival in the laboratory was 2 hours. Each 30 ml of diluted lymphocytes and other mononuclear cells (1:1,2 with Ca2+/Mg2+-free PBS) was then layered gently on top of 15 ml lymphocyte separation medium (LSM, PAA Laboratories GmbH, Pasching, Austria). After centrifugation (400g, 30 min, 20C), the interface of containing mononuclear cells was collected and washed with PBS. The CD34+ progenitor cells were isolated from the collected mononuclear cells using a magnetic separation column (Super Macs II, Miltenyi Biotec, Bergisch Gladbach, Germany) and a mixture of magnetic microbeads conjugated with antibody against CD34 (Miltenyi Biotec) according to the manufacturer's instructions. The pellet which is formed, during centrifugation with LSM, is comprised mostly of erythrocytes and granulocytes that migrated through the gradient. Contaminating erythrocytes were removed by using lysing solution (0.15 M NH4Cl, 0.1 mM Na2EDTA, 12 mM NaHCO3). High quality of purified granulocytes was confirmed by cytospin preparations and Wright–Giemsa staining. The viable CD34+ cell and granulocyte counts were performed with the use of a trypan-blue exclusion technique (BioWhittaker). The purity of recovered cells was determined by flow cytometry using PE–anti-CD34 mAb (BD Biosciences, San Jose, CA, USA) and was over 80% in samples for microarray analysis. Karyotype analysis did not show any chromosome aberrations in samples for microarray analysis.
Project description:The erythropoietin (EPO) hormone induces red blood cell production and its recombinant form is the most prescribed drug for the treatment of anemia, including that arising in cancer patients. Based on randomized trials showing that EPO administration to cancer patients result in a decreased survival, we investigated the impact of EPO modulation on tumorigenesis. Using genetically engineered mouse models of breast cancer we found that EPO promoted tumorigenesis by activating JAK/STAT signaling specifically in breast tumor initiating cells (TICs) and promoting their self-renewal. Moreover, we define an active role for endogenous EPO in breast cancer progression and breast TIC self-renewal and demonstrate a potential application of EPO pathway inhibition in breast cancer therapy. reference x sample
Project description:The I/11 and R10 erythroid progenitor cell line was cultivated in serum free medium (StemPro34) supplemented with Epo (0,5U/ml), SCF (100ng/ml) and dexamethasone (10-6M). To identify genes specifically regulated by Epo/SCF-induced polysome recruitment, cells were factor deprived for 4h and subsequently treated for 2h with 5U/ml Epo and 200ng/ml SCF or left untreated. Subsequently we isolated both total and polysome bound mRNA from each condition, which was hybridised to oligonucleotide arrays (Affymetrix). Analysis of data with Rosetta Resolver allowed to identify and compare Epo/SCF induced gene expression in total and polysome bound RNA. To assess gene expression during erythroid differentiation, cells were induced to differentiate in presence of 5U/ml Epo and 0.5mg/ml Fe-loaded transferrin. Polysome bound mRNA was isolated from cells proliferating in presence of Epo, SCF and dexamethasone (renewal conditions), and from cells induced to differentiate for 48h or 60h.
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 investigated the miRNA expression in ex vivo human erythroid cultures from K562 cells. Hypothetically, the decline of certain miRNAs may promote erythropoiesis by unblocking expression of key functional proteins while the up-regulation of other miRNAs may block commitment to non-erythroid lineages. By comparison with the miRNA expression changes in human umbilical cord blood-derived CD34 cells, signature miRNAs for erythroid development can be discovered. Keywords: miRNA expression profiling Overall design: Human K562 cell line was obtained from ATCC and maintained in IMDM with 10% fetal calf serum (Hyclone). For erythropoietic induction, the cells were adapted to the serum free defined media StemLineII (Sigma) first and then induced to differentiate in the StemLineII media supplemented with 50 ng/ml IL3 and 7.5 U/ml EPO (Mahdi et al. 1998). miRNAs were harvested at regular time points through out this period and hybridized onto the array.
Project description:Homodimerization of Mpl can also be accomplished in the absence of Tpo, by binding of a synthetic ligand (Chemical inducer of dimerization, CID) to a constitutively expressed fusion protein F36VMpl consisting of a ligand binding domain (F36V) and the intracellular signaling domain of Mpl. In contrast to Tpo stimulation, F36VMpl dimerization in human CD34+ progenitor cells generates robust erythropoiesis. Microarray gene expression profiling of progenitors demonstrated that F36VMpl dimerization, but not Tpo, results in upregulation of critical erythroid genes. CD34+ cord blood cells were transduced with F36VMpl-GFP (GFP reporter gene) and cultured on MS-5 stroma for 7 days in the presence of CID, Tpo, Epo or no factors (no CID, negative control). CD34+GFP+ cells were sorted on day 7 and subjected to microarray (n=3 independent experiments).
Project description:Transcriptional profiles of human CD34+ cells cultured in EPO and EST conditions. Overall design: After obtaining informed consent, human CD34+ cells were isolated in high purity from the peripheral blood of normal human volunteers. The cells were cultured at a concentration of 104 - 105 cells/mL in medium supplemented with 4 U/mL Erythropoietin (EPO) versus 4 U/mL Erythropoietin + 50 ng/mL Stem Cell Factor + 1.25 ng/mL Transforming Growth Factor Beta (EST) as described previously. Cells were sampled on culture Day 7, culture Day 14, or both culture days and enumerated using an electronic cell counter (Coulter, Hialeah, FL). Adult and fetal hemoglobin was analysed by HPLC. RNA was extracted using QIAshredder and Rneasy Minikit.