Casirati et al. Epitope Editing of Hematopoietic Stem Cells
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ABSTRACT: Data for the manuscript Casirati et al. "Epitope Editing of Hematopoietic Stem Cells Enables Adoptive Immunotherapies for Acute Myeloid Leukemia"
Project description:A Scalable Epitope Tagging Approach for High Throughput ChIP-seq Analysis ChIP-seq comparison between CRISPR editing cells using epitope antibody and non-editing cells using endogeneous TF antibody
Project description:Ex-vivo gene editing in T cells and hematopoietic stem/progenitor cells (HSPCs) holds promise for treating diseases by non-homologous end joining (NHEJ) gene disruption or homology-driven repair (HDR) gene correction. Gene editing encompasses delivery of nucleases by electroporation and, when aiming to HDR, of a DNA template often provided by viral vectors. Whereas HSPCs activate robust p53-dependent DNA damage response (DDR) upon editing, the responses triggered in T cells remain poorly characterized. Here, we performed comprehensive multi-omics analyses and found that electroporation is the culprit of cytotoxicity in T cells, causing death and cell cycle delay, perturbing metabolism and inducing inflammatory response. Nuclease delivery by lipid nanoparticles (LNPs) nearly abolished cell death and ameliorated cell growth, improving tolerance to the procedure and yielding higher number of edited cells compared to electroporation. Transient transcriptomic changes upon LNP treatment were mostly caused by cellular loading with exogenous cholesterol, whose potentially detrimental impact could be overcome by limiting exposure. Notably, LNP-based HSPC editing dampened p53 pathway induction and supported higher reconstitution by long-term repopulating HSPCs compared to electroporation, reaching similar editing efficiencies. Overall, LNPs may allow efficient and stealthier ex-vivo gene editing in hematopoietic cells for treatment of human diseases.
Project description:Chromatin organization is a highly orchestrated process that influences gene expression, in part by modulating access of regulatory factors to DNA and nucleosomes. We found that the chromatin accessibility regulator HMGN1, a target of recurrent DNA copy gains in leukemia, controls myeloid differentiation. HMGN1 amplification was associated with increased accessibility, expression, and histone H3K27 acetylation of loci important for hematopoietic stem cell (HSC) function and AML, such as HoxA cluster genes. In vivo, HMGN1 overexpression was linked to decreased quiescence and increased HSC activity in bone marrow transplantation. HMGN1 overexpression also cooperated with the AML-ETO9a fusion oncoprotein to impair myeloid differentiation and enhance leukemia stem cell (LSC) activity. Inhibition of histone acetyltransferases CBP/p300 relieved the HMGN1-associated differentiation block. These data nominate factors that modulate chromatin accessibility as regulators of HSCs and LSCs and suggest that targeting HMGN1 or its downstream effects on histone acetylation could be therapeutically active in AML.
Project description:Genome editing provides a potential approach to model de novo leukemogenesis in primary human hematopoietic stem and progenitor cells (HSPCs) through induction of chromosomal translocations by targeted DNA double-strand breaks. However, very low efficiency of translocations and lack of markers for translocated cells serve as barriers to their characterization and model development. Here we utilized TALENs to generate t(9;11) chromosomal translocations encoding MLL-AF9 and reciprocal AF9-MLL fusion products in CD34+ human cord blood cells. Selected cytokine combinations enabled monoclonal outgrowth and immortalization of initially rare translocated cells, which were distinguished by elevated MLL target gene expression, high surface CD9 expression, and increased colony forming ability. Subsequent transplantation into immune-compromised mice induced myeloid leukemias within 48 weeks, whose pathologic and molecular features extensively overlap with de novo patient MLL-rearranged leukemias. No evidence of secondary pathogenic mutations was revealed by targeted exome sequencing and whole genome RNA-seq analyses, suggesting the genetic sufficiency of t(9;11) translocation for leukemia development from human HSPCs. Thus, genome editing enables modeling of human acute MLL-rearranged leukemia in vivo reflecting the genetic simplicity of this disease and provides an experimental platform for biological and disease modeling applications.
Project description:Loss of immune function and an increased incidence of myeloid leukemia are two of the most clinically significant consequences of aging of the hematopoietic system. To better understand the mechanisms underlying hematopoietic aging, we evaluated the cell intrinsic functional and molecular properties of highly purified long-term hematopoietic stem cells (LT-HSCs) from young and old mice. We found that LT-HSC aging was accompanied by cell autonomous changes, including increased stem cell self-renewal, differential capacity to generate committed myeloid and lymphoid progenitors, and diminished lymphoid potential. Expression profiling revealed that LT-HSC aging was accompanied by the systemic down-regulation of genes mediating lymphoid specification and function and up-regulation of genes involved in specifying myeloid fate and function. Moreover, LT-HSCs from old mice expressed elevated levels of many genes involved in leukemic transformation. These data support a model in which age-dependent alterations in gene expression at the stem cell level presage downstream developmental potential and thereby contribute to age-dependent immune decline, and perhaps also to the increased incidence of leukemia in the elderly.
Project description:In this project, we studied how the nucleosome binding protein HMGN1 affects myeloid differentiation and hematopoietic and leukemia stem cell activity
Project description:In this project, we studied how the nucleosome binding protein HMGN1 affects myeloid differentiation and hematopoietic and leukemia stem cell activity.
Project description:In this project, we studied how the nucleosome binding protein HMGN1 affects myeloid differentiation and hematopoietic and leukemia stem cell activity.
Project description:Loss of immune function and an increased incidence of myeloid leukemia are two of the most clinically significant consequences of aging of the hematopoietic system. To better understand the mechanisms underlying hematopoietic aging, we evaluated the cell intrinsic functional and molecular properties of highly purified long-term hematopoietic stem cells (LT-HSCs) from young and old mice. We found that LT-HSC aging was accompanied by cell autonomous changes, including increased stem cell self-renewal, differential capacity to generate committed myeloid and lymphoid progenitors, and diminished lymphoid potential. Expression profiling revealed that LT-HSC aging was accompanied by the systemic down-regulation of genes mediating lymphoid specification and function and up-regulation of genes involved in specifying myeloid fate and function. Moreover, LT-HSCs from old mice expressed elevated levels of many genes involved in leukemic transformation. These data support a model in which age-dependent alterations in gene expression at the stem cell level presage downstream developmental potential and thereby contribute to age-dependent immune decline, and perhaps also to the increased incidence of leukemia in the elderly. 3 old mice and 5 young mice were assayed