Human myelopoiesis is an exciting biological model for cellular differentiation since it represents a plastic process where pluripotent stem cells gradually limit their differentiation potential, generating different precursor cells which finally evolve into distinct terminally differentiated cells. This study aimed at investigating the genomic expression during myeloid differentiation through a computational approach that integrates gene expression profiles with functional information and genome organization. The genomic distribution of myelopoiesis genes was investigated integrating transcriptional and functional characteristics of genes. The analysis of genomic expression during human myelopoiesis using an integrative computational approach allowed discovering important relationships between genomic position, biological function and expression patterns and highlighting chromatin domains, including genes with coordinated expression and lineage-specific functions.
Motif discovery in promoters of genes co-localized and co-expressed during myeloid cells differentiation.
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View SamplesHuman myelopoiesis is an exciting biological model for cellular differentiation since it represents a plastic process where pluripotent stem cells gradually limit their differentiation potential, generating different precursor cells which finally evolve into distinct terminally differentiated cells. This study aimed at investigating the genomic expression during myeloid differentiation through a computational approach that integrates gene expression profiles with functional information and genome organization. The genomic distribution of myelopoiesis genes was investigated integrating transcriptional and functional characteristics of genes. The analysis of genomic expression during human myelopoiesis using an integrative computational approach allowed discovering important relationships between genomic position, biological function and expression patterns and highlighting chromatin domains, including genes with coordinated expression and lineage-specific functions.
Motif discovery in promoters of genes co-localized and co-expressed during myeloid cells differentiation.
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View SamplesSeveral reports indicate that mesalazine (5-aminosalicylic acid or 5-ASA) is a promising candidate for the chemoprevention of Colo-Rectal Cancer (CRC) due to its ability to reach the purpose, yet avoiding at the same time the side effects that are usually determined by prolonged administrations of Non Steroidal Anti-Inflammatory Drugs. This activity of 5-ASA is probably the consequence of a number of effects determined on colon cancer cells and consisting of reduced proliferation, increased apoptosis and activation of cell cycle checkpoints. A recent observation has suggested that these effects could be mediated by the capacity of 5-ASA to interfere with the nuclear translocation of beta-catenin, in turn responsible for the inhibition of its transcription activity. The aim of our study was to better characterize the molecular mechanism by which 5-ASA inhibits the beta-catenin signaling pathway. To address this issue we assessed, by means of the Affymetrix microarray methodology, the transcriptome changes determined on Caco2 cells by a 96 h treatment with 20 mM mesalazine.
Mesalazine inhibits the beta-catenin signalling pathway acting through the upregulation of mu-protocadherin gene in colo-rectal cancer cells.
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Association between gene and miRNA expression profiles and stereotyped subset #4 B-cell receptor in chronic lymphocytic leukemia.
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View SamplesHighly homologous B-cell receptors, stereotyped BCR, are expressed in a recurrent fraction of patients with chronic lymphocytic leukemia (CLL). In this study, we investigated the biological and molecular features of leukemic cells from 16 patients utilizing stereotyped subset #4 BCR (IGHV4-34) in a prospective cohort of 462 Binet stage A CLL patients. All subset #4 patients were characterized by the IGHV mutated gene configuration and by the absence of unfavorable cytogenetic lesions, and NOTCH1 and SF3B1 mutations. Gene expression profiling demonstrated a significant downregulation of WDFY4, MF2A and upregulation of PDGFA, FGFR1 and TFEC genes in leukemic cells from subset #4 compared to those from the remaining IGHV-mutated patients. Similarly, in the cells from subset #4 cases there was a specific miRNA expression pattern involving the upregulation of miR-497 and miR-29c. Furthermore transfection of miR-497 mimic in primary leukemic CLL cells induced a downregulation of BCL2, known to be a validated target of this miRNA. Our data identify a distinct gene and miRNA expression profile of the cells from subset #4 patients, providing further evidence for the putative role of BCR in shaping the features of the leukemic cells.
Association between gene and miRNA expression profiles and stereotyped subset #4 B-cell receptor in chronic lymphocytic leukemia.
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View SamplesAlthough a considerable number of reports indicate an involvement of the Hox-A10 gene in the molecular control of hematopoiesis, the conclusions of such studies are quite controversial since they support, in some cases, a role in the stimulation of stem cell self-renewal and myeloid progenitor expansion while, in others, implicate this transcription factor in the induction of monocyte - macrophage differentiation. To clarify this issue we analyzed the biological effects and the transcriptome changes determined in human primary CD34+ hematopoietic progenitors by retroviral transduction of a full length Hox-A10 cDNA. The results obtained clearly indicated that this homeogene is an inducer of monocyte differentiation, at least partly acting through the up-regulation of MafB gene, recently identified as master regulator of such maturation pathway. By using a combined approach based on computational analysis, EMSA experiments and luciferase assays, we were able to demonstrate the presence of a Hox-A10 binding site in the promoter region of the MafB gene, which suggested the likely molecular mechanism underlying the observed effect. Interestingly, stimulation of the same cells with the Vitamin D3 monocyte differentiation inducer resulted in a clear increase of Hox-A10 and MafB transcripts, indicating the existence of a precise transactivation cascade involving VDR, Hox-A10 and MafB transcription factors. Altogether these data allow to conclude that the Vitamin D3 / Hox-A10 pathway supports MafB function during the induction of monocyte differentiation.
The vitamin D3/Hox-A10 pathway supports MafB function during the monocyte differentiation of human CD34+ hemopoietic progenitors.
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View SamplesNucleotides triphosphates are extracellular messengers binding to specific plasma membrane receptors (P2Rs) that modulate responses as different as proliferation, differentiation, migration or cell death on several cell types including hematopoietic stem cells. Little and controversial information is available on the role of extracellular nucleotides in human mesenchimal stem cells (hMSCs). In this study, we assessed whether P2Rs are expressed and functional in bone marrow-derived hMSCs. Our results demonstrated, at the mRNA and protein level, the expression of all P2X and P2Y receptor subtypes identified so far. P2R activation by their natural ligands adenosine triphosphate (ATP) and uridine triphosphate (UTP) induced in hMSCs, intracellular Ca2+ concentration changes, plasma membrane depolarization and permeabilization. hMSCs were resistant to the cytotoxic effects of high dose ATP despite the expression of permeabilizing P2Rs as demonstrated by the lack of morphological changes, significant release of intracellular markers of cell death or modification of the mitochondrial network. Gene expression profiling revealed the down-regulation of cell proliferation genes whereas genes involved in cell migration and cytokine production were strongly up-regulated by ATP. Functional studies confirmed the inhibitory activity of ATP on proliferation of hMSCs and clonogenic progenitors. Moreover, ATP exerted a chemotactic effect on hMSCs and increased their migration in response to the chemokine CXCL12. Finally, whereas ATP did not affect T-cell inhibitory activity of hMSCs, the nucleotide increased the production of pro-inflammatory cytokines by hMSCs. Thus, our data show that purinergic signaling modulates hMSC functions and point to a role for extracellular nucleotides on hMSCs biology.
Purinergic stimulation of human mesenchymal stem cells potentiates their chemotactic response to CXCL12 and increases the homing capacity and production of proinflammatory cytokines.
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View SamplesHistone deacetylase (HDAC) inhibitors are widely utilized in hematopoietic malignance therapy; nevertheless, little is currently known concerning their effects on normal myelopoiesis. In order to investigate a putative interference of HDAC inhibitors in myeloid commitment of hematopoietic stem/progenitor cells (HSPCs) we treated CD34+ cells with valproic acid (VPA). Moreover, we investigate changes in gene expression induced by VPA treatment on HSPCs, by means of microarray analysis in VPA treated and untreated (CTR) CD34+ cells.
Valproic acid triggers erythro/megakaryocyte lineage decision through induction of GFI1B and MLLT3 expression.
Specimen part, Treatment
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Clinical monoclonal B lymphocytosis versus Rai 0 chronic lymphocytic leukemia: A comparison of cellular, cytogenetic, molecular, and clinical features.
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View SamplesProspective series of 136 clinical monoclonal B lymphocytosis (cMBL) and 216 chronic lymphocytic leukemia (CLL) Rai 0 patients, were investigated in this study. While the distribution of CD38 and ZAP-70 positivity was similar, IGHV-mutated cases were more frequent among cMBL (P = 0.005). A Cox multivariate analysis on the whole patient cohort showed that cMBL condition was predictive of longer PFS, while CD38 expression and IGHV-unmutated status and CD38 expression correlated significantly with a shorter PFS in cMBL and Rai0-CLL, respectively. Trisomy 12, 11q- and 17p- abnormalities were scanty and of no predictive value in both conditions. Notably, gene and miRNA expression profiling showed no significant differences between cMBL and Rai0-CLL. Furthermore, similar gene and miRNA expression signatures were found in cMBL and Rai0-CLL according to the IGHV gene mutational status: that is, unmutated cases had different signatures from mutated cases, irrespectively of the cMBL or CLL condition. Overall, our study based on a prospective series of patients indicates that no major biological differences exist in cMBL compared to Rai0-CLL, suggesting that this two entities mainly differ for the initial size of the monoclonal cell population which may reflect in the longer time for clonal expansion.
Clinical monoclonal B lymphocytosis versus Rai 0 chronic lymphocytic leukemia: A comparison of cellular, cytogenetic, molecular, and clinical features.
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