Project description:This SuperSeries is composed of the following subset Series:; GSE9188: Differentially regulated genes in LT-HSC from control or Pbx1-null mice; GSE9189: Differentially regulated genes in normal LT-HSC vs ST-HSC Experiment Overall Design: Refer to individual Series
Project description:Life-long blood production requires long-term hematopoietic stem cells (LT-HSC) - marked by stemness states involving quiescence and self-renewal - to transition into activated short-term HSC (ST-HSC) with reduced stemness. As few transcriptional changes underlie this transition, we used single-cell and bulk ATAC-seq on human HSC and stem/progenitor subsets (HSPC) to uncover chromatin accessibility signatures, one including LT-HSC (LT/HSPC signature) and another excluding LT-HSC (Act/HSPC signature). These signatures inversely correlated during early hematopoietic commitment and differentiation. The Act/HSPC signature contains CTCF binding sites mediating 351 chromatin interactions, engaged in ST-HSC but not LT-HSC, enclosing multiple stemness pathway genes active in LT-HSC and repressed in ST-HSC. CTCF silencing derepressed stemness genes, restraining quiescent LT-HSC from transitioning to activated ST-HSC. Hence, 3D chromatin interactions centrally mediated by CTCF, endow a gatekeeper function that governs the earliest fate transitions HSC make by coordinating disparate stemness pathways linked to quiescence and self-renewal.
Project description:Here we tracked transcriptional changes in LT, ST-HSC and MLP after transplantation into immunocompromised mice. We show that LT- and ST-HSC activate similar pathways upon transplantation but they modulate distinct sets of genes.
Project description:Purpose: The goal of this study is to compare NGS-derived transcriptome profiling (RNA-seq) of Ltbr-deficient and -proficient LT/ST-HSCs isolated from chimeric mice. Methods: Transcriptomic profiles of Ltbr-/- and Ly5.1 LT/ST-HSCs isolated from chimeric mice 6 weeks after reconstitution were assessed in triplicate by deep sequencing, using Illumina NextSeq 500. qRT–PCR validation was performed using TaqMan and SYBR Green assays. Results: We mapped about 60 million sequence reads per sample to the mouse genome (GRCm38 - mm10) and identified expressed transcripts in Ltbr-/- and Ly5.1 LT/ST-HSCs isolated from chimeric mice. RNA-seq. data confirmed stable expression of known housekeeping genes. Differentially expressed genes between the Ltbr-/- and Ly5.1 LT/ST-HSCs were identified with a fold change ≥1.5 and FDR p-value <0.05. Conclusions: Our study represents the first detailed transcriptome analysis of Ltbr-deficient and -proficient LT/ST-HSCs, with biologic replicates, generated by RNA-seq. technology. Our results show that Ltbr signaling regulates HSC proliferation and differentiation. Evaluation of mRNA content in Ltbr-/- LT/ST-HSCs revealed that Ltbr-deficiency enhances HSC proliferation, differentiation, cell cycle and reduces the activity of canonical NFkB signaling.
Project description:We have developed a new conditional transgenic mouse showing that MLL-ENL, at an endogenous-like expression level, induces leukemic transformation selectively in LT-HSCs. To investigate the molecular mechanism of leukemic transformation in LT-HSCs conditionally expressing MLL-ENL, we preliminarily performed comprehensive gene expression profiling of CreER-transduced LT-HSCs and ST-HSCs using cDNA microarray analysis. For initial screening of candidate genes invloved in the leukemic transformation, total RNA was extracted from colony-forming cells derived from LT-HSCs and ST-HSCs transduced with CreER or mock. Four samples were analyzed, and CreER-transduced LT/ST-HSC-derived cells were compared with mock-transduced LT/ST-HSC-derived cells, while CreER/mock-transduced LT-HSC-derived cells were compared with CreER/mock-transduced ST-HSC-derived cells.
Project description:Here we tracked transcriptional changes in LT, ST-HSC and MLP after transplantation into immunocompromised mice. We show that LT- and ST-HSC activate similar pathways upon transplantation but they modulate distinct sets of genes. Total RNA was obtained from flow-sorted populations of human LT-, ST-HSC and MLP isolated from cord blood or immunocompromised mice transplanted with human at hematopoeitic progenitors at different time points after transplantation.
Project description:We applied a novel approach of parallel transcriptional analysis of multiple, highly fractionated stem and progenitor populations from patients with acute myeloid leukemia (AML) and a normal karyotype. We isolated phenotypic long-term HSC (LT-HSC), short-term HSC (ST-HSC), and committed granulocyte-monocyte progenitors (GMP) from individual patients, and measured gene expression profiles of each population, and in comparison to their phenotypic counterparts from age-matched healthy controls. Bone marrow samples from AML patients with normal karyotype and age-matched healthy controls were used in this study. Hematopoietic stem and progenitor compartments were purified by multiparameter-high speed fluorescence-activated cell sorting (FACS) from CD34+ enriched bone marrow to isolate LT-HSC (Lin-/CD34+/CD38-/CD90+), ST-HSC (Lin-/CD34+/CD38-/CD90-), and GMP (Lin-/CD34+/CD38+/CD123+/CD45R+).
