Project description:IM CD34+ vs BM CD34+ cells Experiment Overall Design: Differential gene expression profiling of CD34+ cells purified from the PB of 15 IM patients (3 distinct pools) and from the BM of 15 healthy subjects (3 distinct pools)
Project description:Tyrosine kinase inhibitors (TKI) are highly effective in treatment of chronic myeloid leukemia (CML) but do not eliminate leukemia stem cells (LSC), which remain a potential source of relapse. TKI treatment effectively inhibits BCR-ABL kinase activity in CML LSC, suggesting that additional kinase-independent mechanisms contribute to LSC preservation. We investigated whether signals from the bone marrow (BM) microenvironment protect CML LSC from TKI treatment. Coculture with human BM mesenchymal stromal cells (MSC) significantly inhibited apoptosis and preserved CML stem/progenitor cells following TKI exposure, maintaining colony forming ability and engraftment potential in immunodeficient mice. We found that the N-Cadherin receptor plays an important role in MSC-mediated protection of CML progenitors from TKI. N-Cadherin-mediated adhesion to MSC was associated with increased cytoplasmic N-Cadherin-M-NM-2-catenin complex formation, as well as enhanced M-NM-2-catenin nuclear translocation and transcriptional activity. Increased exogenous Wnt-mediated M-NM-2-catenin signaling played an important role in MSC-mediated protection of CML progenitors from TKI treatment. Our results reveal a close interplay between N-Cadherin and the Wnt-M-NM-2-catenin pathway in protecting CML LSC during TKI treatment. Importantly, these results reveal novel mechanisms of resistance of CML LSC to TKI treatment, and suggest new targets for treatment designed to eradicate residual LSC in CML patients. RNA was obtained from CML CD34+ cells treated with or without IM (5M-NM-<M) and MSC for 96 hours, amplified, labeled and hybridized to GeneChip 1.0 arrays (Affymetrix, Santa Clara, CA). Microarray data analysis was performed using R (version 2.9) with genomic analysis packages from Bioconductor (version 2.4). The 33297 probes represented on the microarray were filtered by cross-sample mean, and for standard deviation of greater than the 25% quantile, yielding 18624 probes representing 12553 genes. Linear regression was used to model the gene expression with the consideration of a 2x2 factorial design and matched samples. Differentially expressed genes were identified by calculating empirical Bayes moderated t-statistic, and p-values were adjusted by FDR using the M-bM-^@M-^\LIMMAM-bM-^@M-^] package. Gene Set Enrichment Analysis (GSEA) was performed using GSEA software version 2.04 to detect enrichment of predetermined gene sets using t-scores from all genes for 1263 gene sets in the C2 (curated gene sets) category from the Molecular Signature Database (MsigDB).
Project description:In this study we report the identification of a unipotent human neutrophil-committed progenitors (NCPs) within bone marrow (BM) CD34+ and CD34dim/- cells. We show that NCPs can be either CD45RA+ or CD45RA-. By scRNA-seq experiments, we could uncover that NCPs actually consist of four cell clusters (c1-c4), substantially matching with the phenotypic identification of NCPs based on CD34, but not CD45RA, expression. c1-c4 cells were found to be at different maturation levels, aligned along two developmental neutrophil trajectories, as well as characterized by specific gene profiles.
Project description:Homing and engraftment of hematopoietic stem cells (HSCs) to the bone marrow (BM) involve a complex interplay between chemokines, cytokines, and non-peptide molecules. Extracellular nucleotides and their cognate P2 receptors are emerging as key-factors of inflammation and related chemotactic responses. In this study, we investigated the activity of extracellular adenosine-triphosphate (ATP) and uridine-triphosphate (UTP) on CXCL12-stimulated CD34+ HSC chemotaxis. In vitro, UTP significantly improved HSC migration, inhibited cell membrane CXCR4 down-regulation of migrating CD34+ cells and increased cell adhesion to fibronectin. In vivo, pre-incubation with UTP significantly enhanced the BM homing efficiency of human CD34+ cells in immunodeficient mice. Pertussis toxin blocked CXCL12- and UTP-dependent chemotactic responses, suggesting that G-protein alpha-subunits (Gαi) may provide a converging signal for CXCR4- and P2Y-activated transduction pathways. In addition, gene expression profiling of UTP-treated CD34+ cells and in vitro inhibition assays demonstrated that Rho guanosine 5’-triphosphatases (GTPase) Rac2 and downstream effectors Rho GTPase–activated kinases 1 and 2 (ROCK1/2) are involved in UTP-promoted/CXCL12-dependent HSC migration. Our data suggest that UTP may physiologically modulate the migration of HSCs and their homing to the BM, in concert with CXCL12, via the activation of converging signaling pathways between CXCR4 and P2Y receptors, involving Gαi proteins and RhoGTPases. Keywords: treatment comparison
Project description:Philadelphia chromosome-negative myeloproliferative neoplasms (MPN) consist of primary myelofibrosis (PMF), polycythemia vera (PV), essential thrombocythemia (ET) and seconday myelofibrosis (pPV-MF or pET-MF) In this dataset, we compare the gene expression data of bone marrow (BM) or peripheral blood (PB) mononuclear cells of CD34+ cells from JAK2V617F mutated patients vs. healthy donors
Project description:The JAK2V617F mutation has been reported in about 40-60% of Essential Thrombocythemia (ET) patients. However, little is known about specific molecular abnormalities of the hematopoietic stem cell compartment of ET according to JAK2 mutation. Therefore, we compared the gene expression profiles of bone marrow (BM) CD34+ cells from 16 patients with and without the JAK2V617F mutation to identify differentially expressed genes. Keywords: cell type comparison Sample name and JAK2V617F mutation: - BM CD34+ cells from healthy subject (CTR) - ET JAK2V617F-positive: ET 1, ET 4, ET 6, ET 7, ET 8, ET 10, ET 12, ET 15 - ET JAK2V617F-negative: ET 2, ET 3, ET 5, ET 9, ET 11, ET 13, ET 14, ET 16
Project description:The JAK2V617F mutation has been reported in about 40-60% of Essential Thrombocythemia (ET) patients. However, little is known about specific molecular abnormalities of the hematopoietic stem cell compartment of ET according to JAK2 mutation. Therefore, we compared the gene expression profiles of bone marrow (BM) CD34+ cells from 16 patients with and without the JAK2V617F mutation to identify differentially expressed genes. Keywords: cell type comparison
Project description:In order to investigate the role of CD34 antigen in haematopoietic commitment, we overexpressed the human CD34 cDNA in human CD34+ cells by retroviral gene transfer. Keywords: treatment comparison