In order to gain insight into the molecular pathogenesis of the myelodysplastic syndromes (MDS), we performed global gene expression profiling and pathway analysis on the hematopoietic stem cells (HSC) of 183 MDS patients as compared with the HSC of 17 healthy controls. The most significantly deregulated pathways in MDS include interferon signaling, thrombopoietin signaling and the Wnt pathway. Among the most significantly deregulated gene pathways in early MDS are immunodeficiency, apoptosis and chemokine signaling, whereas advanced MDS is characterized by deregulation of DNA damage response and checkpoint pathways. We have identified distinct gene expression profiles and deregulated gene pathways in patients with del(5q), trisomy 8 or 7/del(7q). Patients with trisomy 8 are characterized by deregulation of pathways involved in the immune response, patients with 7/del(7q) by pathways involved in cell survival, whilst patients with del(5q) show deregulation of integrin signaling and cell cycle regulation pathways. This is the first study to determine deregulated gene pathways and ontology groups in the HSC of a large group of MDS patients. The deregulated pathways identified are likely to be critical to the MDS HSC phenotype and give new insights into the molecular pathogenesis of this disorder thereby providing new targets for therapeutic intervention.
Deregulated gene expression pathways in myelodysplastic syndrome hematopoietic stem cells.
Specimen part, Disease
View SamplesIn order to gain insight into the poorly understood pathophysiology of the myelodysplastic syndromes (MDS), we have determined the gene expression profiles of the CD34+ cells of 55 MDS patients using the Affymetrix GeneChip U133 Plus2.0 platform
Gene expression profiles of CD34+ cells in myelodysplastic syndromes: involvement of interferon-stimulated genes and correlation to FAB subtype and karyotype.
No sample metadata fields
View SamplesWe aimed to determine the impact of the common mutations on the transcriptome in myelodysplastic syndromes (MDS). We linked genomic data with gene expression microarray data and we deconvoluted the expression of genes into contributions stemming from each genetic and cytogenetic alteration, providing insights into how driver mutations interfere with the transcriptomic state. We modelled the influence of mutations and expression changes on diagnostic clinical variables as well as survival.
Combining gene mutation with gene expression data improves outcome prediction in myelodysplastic syndromes.
Specimen part, Disease
View SamplesMutations of the splicing factor U2AF1 are frequent in the myeloid malignancy myelodysplastic syndromes (MDS) and in other cancers. Patients with MDS suffer from peripheral blood cytopenias, including anemia, and increasing bone marrow blasts. We investigated the impact of the common U2AF1 S34F mutation on cellular function and mRNA splicing in the main cell lineages affected in MDS. We demonstrated that U2AF1 S34F expression in human hematopoietic progenitors impairs erythroid differentiation, and skews granulomonocytic differentiation towards granulocytes. RNA-sequencing of erythroid and granulomonocytic colonies revealed that U2AF1 S34F induced a higher number of cassette exon splicing events in granulomonocytic than erythroid cells, and altered mRNA splicing of many transcripts (expressed in both cell types) in a lineage-specific manner. The introduction of isoform changes identified in the target genes H2AFY and STRAP into hematopoietic progenitors recapitulated phenotypes associated with U2AF1 S34F expression in erythroid and/or granulomonocytic cells, suggesting a causal link. Importantly, we provided evidence showing that isoform modulation of the U2AF1 S34F target genes H2AFY and STRAP rescues the erythroid differentiation defect in U2AF1 S34F MDS cells, raising the possibility of using splicing modulators therapeutically. These data have critical implications for understanding MDS phenotypic heterogeneity, and for the development of new targeted therapies. Overall design: RNA sequencing was performed to identify the aberrant splicing events associated with U2AF1 S34F mutation (n=3) compared to U2AF1 wild-type (n=3) and empty vector control (n=3) in BFU-E and CFU-G/M colonies respectively.
The U2AF1S34F mutation induces lineage-specific splicing alterations in myelodysplastic syndromes.
Subject
View SamplesThe 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. Overall design: 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.
Disruption of SF3B1 results in deregulated expression and splicing of key genes and pathways in myelodysplastic syndrome hematopoietic stem and progenitor cells.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
CALR mutational status identifies different disease subtypes of essential thrombocythemia showing distinct expression profiles.
Sex, Specimen part, Disease
View SamplesPolycythemia vera (PV) and essential thrombocythemia (ET) are Philadelphia-negative myeloproliferative neoplasms (MPNs) characterized by erythrocytosis and thrombocytosis, respectively. Approximately 95% of PV and 5070% of ET patients harbour the V617F mutation in the exon 14 of JAK2 gene, while about 20-30% of ET patients carry CALRins5 or CALRdel52 mutations. These ET CARL-mutated subjects show higher platelet count and lower thrombotic risk compared to JAK2-mutated patients. Here we showed that CALR-mutated and JAK2V617F-positive CD34+ cells have different gene and miRNA expression profiles. Indeed, we highlighted several pathways differentially activated between JAK2V617F- and CALR-mutated progenitors, i.e. mTOR, MAPK/PI3K and MYC pathways. Furthermore, we unveiled that the expression of several genes involved in DNA repair, chromatin remodelling, splicing and chromatid cohesion are decreased in CALR-mutated cells. According to the low risk of thrombosis in CALR-mutated patients, we also found the down-regulation of several genes involved in thrombin signalling and platelet activation. As a whole, these data support the model in which CALR-mutated ET could be considered as a distinct disease entity from JAK2V617F-positive MPNs and may provide the molecular basis supporting the different clinical features of these patients.
CALR mutational status identifies different disease subtypes of essential thrombocythemia showing distinct expression profiles.
Sex, Specimen part, Disease
View SamplesWe sequenced mRNA from 6 samples of FACsorted telencephalons from E14.5 Sip1|Nkx2-1 knockout and WT|Nkx2-1 control mouse embryos to find differentially expressed genes in the absence of the transcription factor Sip1. Overall design: Examination of mRNA levels in 3 control and 3 Sip1|Nkx2-1 knockout samples
Directed migration of cortical interneurons depends on the cell-autonomous action of Sip1.
Specimen part, Cell line, Subject
View SamplesRegulation of carotenoid composition and shoot branching in Arabidopsis by a chromatin modifying histone methyltransferase, SDG8<br></br>Comparison of transcript profiles between wild type Columbia and ccr1 (carotenoid and chloroplast regulatory) mutant, which contains a mutation in At1g77300 (SDG8)
Regulation of carotenoid composition and shoot branching in Arabidopsis by a chromatin modifying histone methyltransferase, SDG8.
Age
View SamplesSF3B1, SRSF2 and U2AF1 are the most frequently mutated splicing factor genes in MDS. We have performed a comprehensive analysis to determine the impact of these commonly mutated splicing factors on pre-mRNA splicing in the stem/progenitor cells and in the erythroid and myeloid precursors in splicing factor mutant MDS. Using RNA-seq, we determined the aberrantly spliced genes and dysregulated pathways in bone marrow CD34+ cells of a large group of 82 MDS patients. Splicing factor mutations in MDS result in different mechanistic alterations in splicing and largely affect different genes, but these converged in common dysregulated pathways and cellular processes, including RNA splicing, translation and mitochondrial dysfunction, indicating that these mutations operate through common mechanisms in MDS. Many of these dysregulated pathways and cellular processes can be linked to the known disease pathophysiology and to the phenotypes associated with splicing factor mutations in MDS, whilst several others have not been previously associated with MDS, such as sirtuin signalling. Overall design: RNA-sequencing was performed on bone marrow CD34+ hematopoeitic stem and progenitor cells from patients with myelodysplastic syndrome and healthy controls to identify differential splicing between samples with mutations in the splicing factor SF3B1, SRSF2 or U2AF1 comparative to samples from myelodysplactic syndrome patients without mutations in these splicing factors and healthy controls. Processed data for the CD34+ hematopoeitic stem and progenitor cells are available in the files: CPM_table.txt.gz, Count_table.txt.gz and TPM_table.txt.gz. RNA-sequencing was also performed on monocytic, granulocytic and erythroid precursors from the bone marrow of patients with myelodysplastic syndrome and healthy controls to identify aberrant splicing in samples with mutations in splicing factors SF3B1 and SRSF2 comparative from healthy controls. Processed data for the monocytic, granulocytic and erythroid precursors are available in the files: CPM_table_fractions.txt, Count_table_fractions.txt and TPM_table_fractions.txt.
Impact of spliceosome mutations on RNA splicing in myelodysplasia: dysregulated genes/pathways and clinical associations.
Specimen part, Disease, Subject
View Samples