Project description:Early, low risk IPSS (International Prognostic Scoring System) myelodysplasia (MDS) is a heterogeneous disorder where the molecular and cellular haematopoietic defects are poorly understood. To gain insight into this condition, we analyzed gene expression profiles of marrow CD34+ progenitor cells from normal karyotype, low blast count MDS patients, age-matched controls and patients with non-MDS anaemia. The aim of the study was to further understanding of the cellular defect in MDS and to identify biomarkers of disease Experiment Overall Design: Bone marrow (BM) CD34 cells were purified from patients with MDS, non-MDS anemia and from normal donors. Total RNA was extracted from Tri-reagent and quality verified on by capillary electrophoresis (Agilent). RNA was amplified by the Affymetrix small sample protocol. cRNA was hybridised to Affymetrix U133A chips under standard conditions. Initial data was analysed in MAS 5.0
Project description:CD34 positive cells of bone marrow samples from normal and MDS samples were cultured ex vivo into erythroid conditions. We used microarrays to detail the gene expression programm of erythroid cells between normal and pathological (MDS) samples Mononuclear cells from bone marrow samples were selected on the expression of the CD34 membran marker. Then, they were cultured ex vivo during 14 days and total RNA samples were analyzed at day 7, 10 and/or 14 then compared between normal and MDS samples.
Project description:CD34 positive cells of bone marrow samples from normal and MDS samples were cultured ex vivo into erythroid conditions. We used microarrays to detail the gene expression programm of erythroid cells between normal and pathological (MDS) samples
Project description:Myelodysplastic syndromes (MDS) are a group of clonal hematological disorders characterized by ineffective hematopoiesis with morphological evidence of marrow cell dysplasia resulting in peripheral blood cytopenia. Microarray technology has permitted a refined high-throughput mapping of the transcriptional activity in the human genome. Noncoding-RNAs (ncRNAs) transcribed from intronic regions of genes are involved in a number of processes related to post-transcriptional control of gene expression, and in the regulation of exon-skipping and intron retention. Characterization of ncRNAs in progenitor cells and stromal cells of MDS patients could be strategic for understanding gene expression regulation in this disease. In this study, gene expression profiles of CD34+ and stromal cells of MDS patients with refractory anemia with ringed sideroblasts (RARS) subgroup were compared those of healthy individuals, using 44k combined intron-exon oligoarrays, which included probes for protein-coding genes, for sense and antisense strands of totally intronic noncoding (TIN) and for partially intronic noncoding (PIN) RNAs. In CD34+ cells of MDS-RARS patients, 217 genes were significantly differentially expressed (q-value < 0.01) in comparison to healthy individuals, of which 68 (31%) were noncoding transcripts. In stromal cells of MDS-RARS, 13 genes were significantly differentially expressed (q-value < 0.05) in comparison to healthy individuals, of which 4 (30%) were noncoding transcripts. These results demonstrated, for the first time, in CD34+ cells and stromal cells the differential ncRNA expression profile between MDS-RARS and healthy individuals, suggesting that ncRNAs may play an important role during the development of myelodysplastic syndromes. Bone marrow (BM) CD34+ cell samples were collected from 4 healthy subjects and from 4 MDS patients. Stromal samples were collected from 4 healthy subjects and 3 MDS patients. All patients were diagnosed as RARS according to the French-American-British (FAB) classification and did not present chromosomal abnormalities; they received no growth factors or any further MDS treatment.
Project description:Early, low risk IPSS (International Prognostic Scoring System) myelodysplasia (MDS) is a heterogeneous disorder where the molecular and cellular haematopoietic defects are poorly understood. To gain insight into this condition, we analyzed gene expression profiles of marrow CD34+ progenitor cells from normal karyotype, low blast count MDS patients, age-matched controls and patients with non-MDS anaemia. The aim of the study was to further understanding of the cellular defect in MDS and to identify biomarkers of disease Keywords: Disease v normal
Project description:An increasing body of work reveals aberrant hypermethylation of genes occurring in and potentially contributing to the pathogenesis of myeloid malignancies. Several of these diseases, such as myelodysplastic syndromes (MDS), are responsive to DNA methyltransferase inhibitors. In order to determine the extent of promoter hypermethylation in such tumors we compared the distribution of DNA methylation of 14,000 promoters in MDS and secondary AML patients enrolled in a phase I trial of 5-azacytidine and the histone deacetylase inhibitor entinostat against de novo AML patients and normal CD34+ bone marrow cells. The MDS and secondary AML patients displayed more extensive aberrant DNA methylation involving thousands of genes than did the normal CD34+ bone marrow cells or de novo AML blasts. Aberrant methylation in MDS and secondary AML tended to affect particular chromosomal regions, occurred more frequently in Alu poor genes, and included prominent involvement of genes involved in the WNT and MAPK signaling pathways. DNA methylation was also measured at days 15 and 29 after the first treatment cycle. DNA methylation was reversed at day 15 in a uniform manner throughout the genome, and this effect persisted through day 29, even without continuous administration of the study drugs. Keywords: DNA methylation profiling Direct comparison of DNA methylation in bone marrow samples from patients with Myelodysplastic syndrome or secondary Acute Myeloid Leukemia (AML) at baseline and after in vivo treatment with 5-azacytidine + etinostat. A comparison to de novo normal karyotype AML was also performed. Two control groups were included: one consisting of 8 CD34+ bone marrow samples from healthy donors and a second one consisting of matched CD34+ and CD34- fractions from the bone marrows of 4 healthy donors.
Project description:The splicing factor SF3B1 is the most commonly mutated gene in the myelodysplastic syndromes (MDS), particularly in patients with refractory anemia with ring sideroblasts (RARS). MDS is a disorder of the hematopoietic stem cell and we thus studied the transcriptome of CD34+ cells from MDS patients with SF3B1 mutations using RNA-sequencing. Genes significantly differentially expressed at the transcript and/or exon level in SF3B1 mutant compared to wildtype cases include genes involved in MDS pathogenesis (ASXL1, CBL), iron homeostasis and mitochondrial metabolism (ALAS2, ABCB7, SLC25A37) and RNA splicing/processing (PRPF8, HNRNPD). Many genes regulated by a DNA damage-induced BRCA1-BCLAF1-SF3B1 protein complex showed differential expression/splicing in SF3B1 mutant cases. Our data indicate that SF3B1 plays a critical role in MDS by affecting the expression and splicing of genes involved in specific cellular processes/pathways, many of which are relevant to the known RARS pathophysiology, suggesting a causal link. RNA-Seq was performed to compare the transcriptome of bone marrow CD34+ cells from eight MDS patients with SF3B1 mutation, four MDS patients with no known splicing mutation and five healthy controls.
Project description:Epigenetic mechanisms contribute to deregulated gene expression of hematopoietic progenitors in Myelodysplastic Syndromes (MDS). Hypomethylating agents are able to improve peripheral cytopenias in MDS patients. To identify critical gene expression changes induced by hypomethylating agents, we analyzed gene expression profiling (GEP) of myelodysplastic and normal CD34+ hematopoietic stem cells treated in vitro with or without decitabine. Four MDS and two untreated early stage Hodgkin’s lymphomas were analyzed for GEP. Mock treated CD34+ stem cells segregate according to diagnosis and karyotype. After decitabine treatment, gene expression changes were more consistent on MDS CD34+ cells with abnormal kayotype. Comparing decitabine-induced genes with those found down-regulated in mock-treated MDS cells, we identified a list of candidate tumor suppressor genes in MDS. By real-time RT-PCR we confirmed expression changes for three selected genes CD9, CXCR4 and GATA2 in 12 MDS patients and 4 controls. CD9 was widely repressed in most MDS CD34+ cell samples, although similar levels of methylation were found in both normal and MDS total bone marrows. CXCR4 promoter methylation was absent in total bone marrows from 36 MDS patients. In conclusion, changes in gene expression changes induced by hypomethylating treatment are more pronounced in CD34+ cells from abnormal karyotype.
Project description:Myelodysplastic syndromes (MDS) are a heterogenous group of hematopoietic stem cell disorders characterized by dysplastic blood cell formation and peripheral blood cytopenias. Up to 30% of patients with MDS will progress to a highly chemotherapy-resistant secondary acute myeloid leukemia (sAML). We identified mutations in U2AF1 in MDS patients and patients with U2AF1 mutations are at an increased risk of developing sAML. We identified mutations in U2AF1 in patients with MDS and hypothesized that U2AF1 mutations may represent a novel mechanism that could alter gene expression in MDS. To elucidate gene expression changes associated with U2AF1 mutations, we analyzed the global mRNA expression profile obtained from bone marrow CD34+ cells purified from 5 MDS patients with a U2AF1 mutation, 10 MDS patients without a mutation, and 4 normal donors.
Project description:Recent studies have shown that multiple components of the mRNA splicing machinery are mutated in myelodysplastic syndrome (MDS) patients. SF3B1 is frequently mutated in refractory anemia with ringed sideroblasts (RARS)-MDS patients, however, the pathophysiological role of SF3B1 mutations has not been elucidated yet. In this study, we examined the function of Sf3b1 in murine hematopoiesis. Since Sf3b1 null homozygotes died during preimplantation development, in this study, we utilized Sf3b1 heterozygous mice showing grossly normal growth. We harvested bone marrow stem/progenitor (LSK) cells from wild type (WT) and Sf3b1+/- mice (n=4) at 20 weeks old. In addition, to exclude the possibility of indirect effect from bone marrow environment, we transplanted total bone marrow cells from WT or Sf3b1+/- (CD45.2+) mice into lethally irradiated CD45.1+ recipient mice, and then harvested (CD45.2+) LSK cells from the recipients (n=5) at 9 months-post transplantation.