Project description:Precise study of HSCs during regeneration has been impeded by the rarity of the HSC population and depletion of phenotypic HSCs early following genotoxic stresses, such as total body irradiation (TBI). We isolated bone marrow (BM) ckit+sca-1+lin- (KSL) cells, which are enriched for HSCs, from adult C57Bl6 mice before and at several time points following TBI, as a means to map the dynamic molecular response of HSC regeneration. We isolated BM KSL cells and myeloid progenitor cells (c-kit+sca-1-lin- cells) at day +14 after irradiation and compared the gene expression profile of regenerating HSCs versus steady state HSCs (non-irradiated) and committed progenitor cells.
Project description:Transcriptional profiling of murine bone marrow c-kit+, Sca-1+ lineage neative (KSL) cells from p21CDKN1a-/- and p21+/+ overexpressing Flt3/ITD. The goal was to determine the effect on global gene expression by loss of p21 in Flt3/ITD transformed KSL cells Internal tandem duplication (ITD) mutations in the Flt3 gene (Flt3-ITD) are associated with poor prognosis in patients with acute myeloid leukemia (AML). Few inhibitors of Flt3-ITD are effective against Flt3-ITD+ AML due to the development of drug-resistance. In this study, we demonstrate that Flt3-ITD activates a novel pathway involving p21Cdkn1a (p21) and pre-B cell leukemia transcription factor 1 (Pbx1) that attenuates Flt3-ITD cell proliferation and is involved in the development drug resistance. Flt3-ITD up-regulated p21 expression in mouse bone marrow c-kit+-Sca-1+-Lin- (KSL) cells and in Ba/F3 cells. Loss of p21 expression enhanced growth factor-independent proliferation and sensitivity to cytarabine as a consequence of enriching the S+G2/M phase population concomitant with a significant increase in the expression of Pbx1, but not Evi-1, in Flt3-ITD+ cells. This enhancement of cell proliferation by loss of p21 was partially abrogated when Pbx1 expression was silenced in Flt3-ITD+ primary bone marrow colony-forming cells (CFCs) and Ba/F3 cells. Antagonizing Flt3-ITD using AC220, a selective inhibitor of Flt3-ITD, decreased the expression of p21, coincident with the up-regulation of Pbx1 mRNA and a rapid decline in the number of viable Flt3-ITD+ Ba/F3 cells, however the cells eventually became refractory to AC220. Overexpressing p21 in Flt3-ITD+ Ba/F3 cells delayed the emergence of cells refractory to AC220, whereas silencing p21 accelerated their development. These data demonstrate that Flt3-ITD is capable of inhibiting the proliferation of Flt3-ITD+ cells through the p21/Pbx1 axis and that antagonizing Flt3-ITD contributes to the subsequent development of cells refractory to Flt3-ITD inhibitor by disrupting p21 expression. biological replicates: 3 KSL cell replicates overexpressing ITD-Flt3 from p21+/+ and p21-/- cells, 1 KSL cell replicate from p21+/+ and p21-/- cells
Project description:The Notch signaling pathway plays a critical role in regulating the proliferation and differentiation of stem and progenitor cells including hematopoietic stem and progenitor cells (HSPCs). Notch receptors and ligands are expressed in BM stromal and hematopoietic cells. A large body of evidence has demonstrated that activating Notch signaling enhances HSCs self-renewal and facilitates its expansion ex vivo. We report that an endothelium-targeted soluble Notch ligand, the DSL domain of mouse Delta-like 1 fused with a RGD motif (mD1R), efficiently promotes the expansion ex vivo of mouse bone marrow HSPCs in a Notch signaling and endocytosis dependent manner. HSPCs expanded in the presence of mD1R kept long-term HSPC repopulation capacity. We used microarrays to compare the gene expression profiles of HSPCs expanded in the presence of PBS and mD1R. KSL cells were plated on Human umbilical vein endothelial cells (HUVECs) and cultured in a serum-free medium supplemented with a cocktail containing 5 types of mouse cytokines (m5GF) in the presence of PBS or mD1R for 7 days. Then KSL cells were sorted from these cultured hematopoietic cells for RNA extraction and hybridization on Affymetrix microarrays. The experiments were repeated 3 times.
Project description:Analyses of gene expression by RNA-Seq in mouse E14.5 fetal liver burst-forming unit erythroid (BFU-E) cells untreated or treated by dexamethasone (DEX) with or without PPAR? agonist GW7647. RNA-Seq was performed on enriched populations of mouse BFU-E isolated from E14.5 fetal liver, as well as BFU-E enriched cells treated with Dex ± GW7647.
Project description:To determine the molecules involved in beta3 integrin signaling in HSCs, we carried out DNA microarray analyses using HSCs stimulated with ligand-mimic antibody for intetegrin beta3 in the presence of stem cell factor(SCF) and/or thrombopoietin (TPO). All experiments were performed in duplicate or triplicate using sorted cells that were independently prepared in separate experiments. After CD34-KSL HSCs were cultured with 2C9.G2 or control IgG for 5 days in S-Clone SF-03 medium supplemented with 50 ng/ml SCF and/or 50 ng/ml TPO, gene expression profiles were examimed using 5,000 sorted CD48-KSL cells from each sample.
Project description:Early erythroid progenitors were isolated from mouse E14.5 fetal liver, infected with viruses encoding either control shRNA or shRNAs targeting the RNA binding protein (RBP), and cultured in a medium containing stem cell factor, erythropoietin, and insulin-like growth factor 1, in the absence or presence of dexamethasone (DEX). After 3 days of culture, microarray experiments were carried out to profile the gene expression pattern of these cells. Examination of mRNA expression profiles in day3 cultured cells
Project description:We investigated the role of amino acid to maintain HSC function. To identify essential amino acids for HSCs, CD34-KSL cells were cultured in single amino acids deficient medium. And cultured cells were transplanted into lethally irradiated mice. Then, the donor chimerism and lineage contribution was estimated. Surprisingly, HSC proliferation was prevented in valine and cysteine deficient medium in vitro. Donor cells cultured in these medium were also not engrafted. To elucidate the effects and influences of cysteine and valine in HSCs, we performed global gene expression profiling experiments by RNA-sequencing analysis. Gene sets categorized with cell cycle, mitosis, cell division or DNA replication were strongly down-regulated in both valine- or cysteine-depleted conditions These results imply distinctive amino-acid metabolism involved in HSC division. Gene expression profiles of ten thousand HSCs cultured in cysteine or valine deficient medium for 24 hours were compared with that of HSCs cultured in complete medium by using RNA-sequencing analysis
Project description:The transcriptome of Ctrl and Vitamin A-deficient longterm hematopoietic stem cells (LT-HSC) and multipotant progenitors (MPP3/4) was assessed by RNAseq.