| 1. |
- Mandal, Pankaj K, et al.
(författare)
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Efficient Ablation of Genes in Human Hematopoietic Stem and Effector Cells using CRISPR/Cas9.
- 2014
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Ingår i: Cell Stem Cell. - : Elsevier BV. - 1934-5909. ; 15:5, s. 643-652
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Tidskriftsartikel (refereegranskat)abstract
- Genome editing via CRISPR/Cas9 has rapidly become the tool of choice by virtue of its efficacy and ease of use. However, CRISPR/Cas9-mediated genome editing in clinically relevant human somatic cells remains untested. Here, we report CRISPR/Cas9 targeting of two clinically relevant genes, B2M and CCR5, in primary human CD4(+) T cells and CD34(+) hematopoietic stem and progenitor cells (HSPCs). Use of single RNA guides led to highly efficient mutagenesis in HSPCs but not in T cells. A dual guide approach improved gene deletion efficacy in both cell types. HSPCs that had undergone genome editing with CRISPR/Cas9 retained multilineage potential. We examined predicted on- and off-target mutations via target capture sequencing in HSPCs and observed low levels of off-target mutagenesis at only one site. These results demonstrate that CRISPR/Cas9 can efficiently ablate genes in HSPCs with minimal off-target mutagenesis, which could have broad applicability for hematopoietic cell-based therapy.
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| 2. |
- Morcos, M. N. F., et al.
(författare)
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Continuous mitotic activity of primitive hematopoietic stem cells in adult mice
- 2020
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Ingår i: Journal of Experimental Medicine. - : Rockefeller University Press. - 0022-1007 .- 1540-9538. ; 217:6
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Tidskriftsartikel (refereegranskat)abstract
- The proliferative activity of aging hematopoietic stem cells (HSCs) is controversially discussed. Inducible fluorescent histone 2B fusion protein (H2B-FP) transgenic mice are important tools for tracking the mitotic history of murine HSCs in label dilution experiments. A recent study proposed that primitive HSCs symmetrically divide only four times to then enter permanent quiescence. We observed that background fluorescence due to leaky H2B-FP expression, occurring in all H2B-FP transgenes independent of label induction, accumulated with age in HSCs with high repopulation potential. We argue that this background had been misinterpreted as stable retention of induced label. We found cell division-independent half-lives of H2B-FPs to be short, which had led to overestimation of HSC divisional activity. Our data do not support abrupt entry of HSCs into permanent quiescence or sudden loss of regeneration potential after four divisions, but show that primitive HSCs of adult mice continue to cycle rarely.
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| 3. |
- Olén, Ola, et al.
(författare)
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Increasing Risk of Lymphoma Over Time in Crohn's Disease but Not in Ulcerative Colitis : A Scandinavian Cohort Study
- 2023
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Ingår i: Clinical Gastroenterology and Hepatology. - : Elsevier. - 1542-3565 .- 1542-7714. ; 21:12, s. 3132-3142
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Tidskriftsartikel (refereegranskat)abstract
- Background & Aims: Earlier studies have provided varying risk estimates for lymphoma in patients with inflammatory bowel disease (IBD), but often have been limited by detection biases (especially during the first year of follow-up evaluation), misclassification, and small sample size; and rarely reflect modern-day management of IBD.Methods: We performed a binational register-based cohort study (Sweden and Denmark) from 1969 to 2019. We compared 164,716 patients with IBD with 1,639,027 matched general population reference individuals. Cox regression estimated hazard ratios (HRs) for incident lymphoma by lymphoma subtype, excluding the first year of follow-up evaluation.Results: From 1969 to 2019, 258 patients with Crohn's disease (CD), 479 patients with ulcerative colitis (UC), and 6675 matched reference individuals developed lymphoma. This corresponded to incidence rates of 35 (CD) and 34 (UC) per 100,000 person-years in IBD patients, compared with 28 and 33 per 100,000 person-years in their matched reference individuals. Although both CD (HR, 1.32; 95% CI, 1.16–1.50) and UC (HR, 1.09; 95% CI, 1.00–1.20) were associated with an increase in lymphoma, the 10-year cumulative incidence difference was low even in CD patients (0.08%; 95% CI, 0.02–0.13). HRs have increased in the past 2 decades, corresponding to increasing use of immunomodulators and biologics during the same time period. HRs were increased for aggressive B-cell non-Hodgkin lymphoma in CD and UC patients, and for T-cell non-Hodgkin lymphoma in CD patients. Although the highest HRs were observed in patients exposed to combination therapy (immunomodulators and biologics) or second-line biologics, we also found increased HRs in patients naïve to such drugs.Conclusions: During the past 20 years, the risk of lymphomas have increased in CD, but not in UC, and were driven mainly by T-cell lymphomas and aggressive B-cell lymphomas.
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| 4. |
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| 5. |
- Jaako, P., et al.
(författare)
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Induction of the 5S RNP-Mdm2-p53 ribosomal stress pathway delays the initiation but fails to eradicate established murine acute myeloid leukemia
- 2017
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Ingår i: Leukemia. - : NATURE PUBLISHING GROUP. - 0887-6924 .- 1476-5551. ; 31:1, s. 213-221
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Tidskriftsartikel (refereegranskat)abstract
- Mutations resulting in constitutive activation of signaling pathways that regulate ribosome biogenesis are among the most common genetic events in acute myeloid leukemia (AML). However, whether ribosome biogenesis presents as a therapeutic target to treat AML remains unexplored. Perturbations in ribosome biogenesis trigger the 5S ribonucleoprotein particle (RNP)-Mdm2-p53 ribosomal stress pathway, and induction of this pathway has been shown to have therapeutic efficacy in Myc-driven lymphoma. In the current study we address the physiological and therapeutic role of the 5S RNP-Mdm2-p53 pathway in AML. By utilizing mice that have defective ribosome biogenesis due to downregulation of ribosomal protein S19 (Rps19), we demonstrate that induction of the 5S RNP-Mdm2-p53 pathway significantly delays the initiation of AML. However, even a severe Rps19 deficiency that normally results in acute bone marrow failure has no consistent efficacy on already established disease. Finally, by using mice that harbor a mutation in the Mdm2 gene disrupting its binding to 5S RNP, we show that loss of the 5S RNP-Mdm2-p53 pathway is dispensable for development of AML. Our study suggests that induction of the 5S RNP-Mdm2-p53 ribosomal stress pathway holds limited potential as a single-agent therapy in the treatment of AML.
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| 6. |
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| 7. |
- Takahashi, M., et al.
(författare)
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Reconciling Flux Experiments for Quantitative Modeling of Normal and Malignant Hematopoietic Stem/Progenitor Dynamics
- 2021
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Ingår i: Stem Cell Reports. - : Elsevier BV. - 2213-6711. ; 16:4, s. 741-753
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Tidskriftsartikel (refereegranskat)abstract
- Hematopoiesis serves as a paradigm for how homeostasis is maintained within hierarchically organized cell populations. However, important questions remain as to the contribution of hematopoietic stem cells (HSCs) toward maintaining steady state hematopoiesis. A number of in vivo lineage labeling and propagation studies have given rise to contradictory interpretations, leaving key properties of stem cell function unresolved. Using processed flow cytometry data coupled with a biology-driven modeling approach, we show that in vivo flux experiments that come from different laboratories can all be reconciled into a single unifying model, even though they had previously been interpreted as being contradictory. We infer from comparative analysis that different transgenic models display distinct labeling efficiencies across a heterogeneous HSC pool, which we validate by marker gene expression associated with HSC function. Finally, we show how the unified model of HSC differentiation can be used to simulate clonal expansion in the early stages of leukemogenesis. © 2021 The Authors
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| 10. |
- Ugale, A., et al.
(författare)
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MLL-ENL-mediated leukemia initiation at the interface of lymphoid commitment
- 2017
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Ingår i: Oncogene. - : Springer Science and Business Media LLC. - 0950-9232 .- 1476-5594. ; 36, s. 3207-3212
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Tidskriftsartikel (refereegranskat)abstract
- Translocations involving the mixed lineage leukemia-1 are recurrent events in acute leukemia and associate with lymphoid (ALL), myeloid (AML) or mixed lineage (MLL) subtypes. Despite an association with ALL in humans, murine MLL fusion models are persistently restricted to AML. We here explored this issue using an inducible mixed lineage leukemia-eleven nineteen leukemia (MLL-ENL) mouse model. Although multiple progenitor cell types with myeloid potential are potent AML leukemia-initiating cells, also the earliest lymphoid progenitors were capable of initiating AML. This ability to evoke a latent myeloid potential in the earliest lymphoid progenitors was lost upon further lymphoid commitment. At the same time, more downstream/committed lymphoid precursors also failed to initiate lymphoid leukemia. Co-expression of MLL-ENL with a constitutively active RAS allele, the most common co-mutation in MLL fusion leukemias, could influence on both disease latency and lineage assignment of developing leukemia in what appears to be a mutation-order-dependent manner. Finally, CEBPB-mediated transdifferentation of committed and otherwise leukemia-incompetent B-cell progenitors imbued these cells with leukemic competence for AML. Therefore, apart from providing detailed insight into the differential responsiveness of candidate target cells to a first-hit MLL fusion event, our data warrants caution to therapeutic approaches based on the concept of transdifferentiation.Oncogene advance online publication, 9 January 2017; doi:10.1038/onc.2016.470.
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