Project description:We used microarray to create a normal cell landscape for the myeloid arm of the hematopoietic system. Mononuclear bone marrow cells from heathly donors were enriched for 34+ and hematopoietic stem and progenitor cells were sorted by FACS.
Project description:Several individual miRNAs (miRs) have been implicated as potent regulators of important processes during normal and malignant hematopoiesis. In addition, many miRs have been shown to fine-tune intricate molecular networks, in concert with other regulatory elements. In order to study hematopoietic networks as a whole, we first created a comprehensive map of global miR expression during early murine hematopoiesis. Next, we determined the copy number per cell for each miR in each of the examined stem and progenitor cell types. As data is emerging indicating that miRs function robustly mainly when they are expressed above a certain threshold (~100 copies per cell), our database provides a resource for determining which miRs are expressed at a potentially functional level in each cell type. Finally, we combine our miR expression map with matched mRNA expression data and external prediction algorithms, using a Bayesian modeling approach to create a global landscape of predicted miR-mRNA interactions within each of these hematopoietic stem and progenitor cell subsets. This approach identifies several interaction networks comprising a “stemness” signature in the most primitive hematopoietic stem cell (HSC) populations, as well as “myeloid” patterns associated with two branches of myeloid development. Six populations of mouse hematopoietic stem and progenitors have been analyzed (LT-HSC, ST-HSC, MPP, CMP, GMP, MEP). 2-3 replicates are included for each sample.
Project description:Several individual miRNAs (miRs) have been implicated as potent regulators of important processes during normal and malignant hematopoiesis. In addition, many miRs have been shown to fine-tune intricate molecular networks, in concert with other regulatory elements. In order to study hematopoietic networks as a whole, we first created a comprehensive map of global miR expression during early murine hematopoiesis. Next, we determined the copy number per cell for each miR in each of the examined stem and progenitor cell types. As data is emerging indicating that miRs function robustly mainly when they are expressed above a certain threshold (~100 copies per cell), our database provides a resource for determining which miRs are expressed at a potentially functional level in each cell type. Finally, we combine our miR expression map with matched mRNA expression data and external prediction algorithms, using a Bayesian modeling approach to create a global landscape of predicted miR-mRNA interactions within each of these hematopoietic stem and progenitor cell subsets. This approach identifies several interaction networks comprising a “stemness” signature in the most primitive hematopoietic stem cell (HSC) populations, as well as “myeloid” patterns associated with two branches of myeloid development. Six populations of mouse hematopoietic stem and progenitors have been analyzed (LT-HSC, ST-HSC, MPP, CMP, GMP, MEP). 2-3 replicates are included for each sample.
Project description:Aim of the experiment was to compare the genes enriched in the heavy polysome fraction of myeloid progenitors originating from control Elp3fl/fl mice, and in myeloid progenitors originating from mice that underwent hematopoietic cell-restricted deletion of the catalytic subunit Elp3 of the Elongator complex (Elp3HscKO mice). The Elp3fl/fl strain was generated in house and first described in (DOI: 10.1084/jem.20142288). Littermates of 8-12 weeks old were used in all experiments.
Project description:Investigation of immune cell differentiation and function is limited by shortcomings of suitable and scalable experimental systems. Although forced expression of certain Hox genes allows immortalization of hematopoietic progenitor cells, their differentiation potential is limited to select myeloid lineages. Here we show that an estrogen-regulated form of Hoxb8 that is retrovirally delivered into bone marrow cells can be used along with FLT3 ligand to conditionally immortalize early hematopoietic progenitor cells (Hoxb8-FL). Hoxb8-FL cells have lost self-renewal capacity and the ability to adopt megakaryocyte/ erythroid lineage fates, but sustain myeloid and lymphoid differentiation potential. Hoxb8-FL cells differentiate in vitro and in vivo into different myeloid and lymphoid cell types, including macrophages, granulocytes, dendritic cells and B- and T-lymphocytes, which are phenotypically and functionally indistinguishable from their primary counterparts. Given the simplicity to generate Hoxb8-FL cells and their unlimited proliferative capacity, this system provides unique opportunities to investigate cell differentiation and immune cell functions. Hoxb8 expressing immortalized cells
Project description:Increasing evidence links metabolic activity and cell growth to decline in hematopoietic stem cell (HSC) function during aging. The Lin28b/Hmga2 pathway controls tissue development and in the hematopoietic system the postnatal downregulation of this pathway causes a decrease in self renewal of adult HSCs compared to fetal HSCs. Igf2bp2 is an RNA binding protein and a mediator of the Lin28b/Hmga2 pathway, which regulates metabolism and growth signaling by influencing RNA stability and translation of its target genes. It is currently unknown whether Lin28/Hmga2/Igf2bp2 signaling impacts on aging-associated impairments in HSC function and hematopoiesis. Here, we analyzed homozygous Igf2bp2 germline knockout mice and wildtype control animals to address this question. The study shows that Igf2bp2 deletion rescues aging phenotypes of the hematopoietic system, such as the expansion of HSC numbers in bone marrow and the biased increase of myeloid cells in peripheral blood. This rescue of hematopoietic aging coincides with reduced mitochondrial metabolism and glycolysis in Igf2bp2-/- HSCs compared to Igf2bp2+/+ HSCs. Conversely, Igf2bp2 overexpression activates protein synthesis pathways in HSCs and leads to a rapid loss of self renewal by enhancing myeloid skewed differentiation in an mTOR/PI3K-dependent manner. Together, these results show that Igf2bp2 regulates energy metabolism and growth signaling in HSCs and that the activity of this pathways influences self renewal, differentiation, and aging of HSCs.
Project description:Data for the manuscript Casirati et al. "Epitope Editing of Hematopoietic Stem Cells Enables Adoptive Immunotherapies for Acute Myeloid Leukemia"