| 1. |
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| 2. |
- Eriksson, Björn, et al.
(författare)
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Establishment and characterization of a mouse strain (TLL) that spontaneously develops T-cell lymphomas/leukemia
- 1999
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Ingår i: Experimental Hematology. - 0301-472X .- 1873-2399. ; 27:4, s. 682-688
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Tidskriftsartikel (refereegranskat)abstract
- In this study, a mouse strain (TLL) that spontaneously develops T-cell lymphomas/leukemia with an early onset and high incidence was established and characterized. All tumors analyzed were found to express the alpha,beta T-cell receptor, and the majority of them had a mature, CD3+CD4+CD8- immunophenotype. In a few cases, tumors with a more immature CD3+CD4+CD8+ phenotype were isolated. Expanded phenotyping using a broad panel of lymphocyte differentiation markers confirmed the mature T-cell phenotype of the tumors. Histologic and cell cycle analysis of the tumors revealed an aggressive lymphoblastic malignancy with a very high proliferation rate and widespread engagement of bone marrow and lymphoid as well as nonlymphoid organs. Thus, the TLL mouse strain represents a unique model for the analysis of the oncogenesis and progression of mature T-cell tumors and for the development of therapeutic measures to combat such tumors.
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| 3. |
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| 5. |
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| 6. |
- Pinto do O, Perpetua, et al.
(författare)
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Multipotent hematopoietic progenitor cells immortalized by Lhx2 self-renew by a cell nonautonomous mechanism
- 2001
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Ingår i: Experimental Hematology. - : Elsevier. - 0301-472X .- 1873-2399. ; 29:8, s. 1019-1028
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Direct molecular and cellular studies of hematopoietic stem cells (HSCs) are hampered by the low levels of HSCs in hematopoietic tissues. To address these issues, we generated immortalized multipotent hematopoietic precursor cell (HPC) lines by expressing the LIM-homeobox gene Lhx2 (previously LH2) in hematopoietic progenitors derived from embryonic stem cells differentiated in vitro.MATERIALS AND METHODS: To validate further the relevance of the HPC lines as a model for normal HSCs, we analyzed in detail the growth requirements of HPC lines in vitro.RESULTS: Lhx2 immortalized the HPC lines by a putatively novel and cell nonautonomous mechanism. Self-renewal of the HPC lines is dependent on functional Lhx2 expression. Most early-acting hematopoiesis-related growth factors show synergistic effects on the HPC lines, whereas late-acting factors do not induce differentiation by themselves. Transforming growth factor-beta(1) is a potent inhibitor of proliferation of the HPC lines. HPC lines form cobblestone areas with high efficiency when seeded onto stromal cell lines, and the cobblestone area-forming cell can be maintained in these cultures for several months.CONCLUSIONS: Our data show that, in many respects, HPC lines are similar to normal hematopoietic progenitor/stem cells on the cellular level, in contrast to most previously described multipotent hematopoietic cell lines. The cell nonautonomous mechanism for immortalization of the HPC lines suggests that Lhx2 regulates, directly or indirectly, soluble mediators involved in self-renewal of the HPC lines.
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| 7. |
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| 9. |
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| 10. |
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| 11. |
- Alves, Rita, et al.
(författare)
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GATA2 at the mitosis-to-G1 transition is critical for definitive hematopoiesis
- 2021
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Ingår i: Experimental Hematology. - : Elsevier BV. - 1873-2399 .- 0301-472X. ; 100:Suppl, s. 35-35
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Konferensbidrag (refereegranskat)abstract
- In mitosis, transcription factors (TFs) and RNA polymerase disperse across the cytoplasm leading to transcriptional silencing, but some TFs are retained on condensed chromatin and mark genomic sites, a mechanism termed mitotic bookmarking. In pluripotent and differentiated cells this mechanism is important for pluripotency maintenance, cell reprogramming and lineage inheritance. However, the role of bookmarking in adult stem cells or in an in vivo system is yet to be addressed. Hematopoietic stem cells undergo drastic changes in cell cycle during development while balancing self-renewal and differentiation, suggesting a possible role for bookmarking.Here, we first addressed the mitotic retention capacity of the hemogenic TFs GATA2, GFI1B and FOS. We show that GATA2 remains bound to chromatin at all phases of cell cycle, as opposed to GFI1B and FOS. The C-terminal zinc finger (C-ZF) and the nuclear localization signal domains are required for GATA2 mitotic binding. Point mutations in the C-ZF associated with leukemia also impact GATA2 retention. To address the role of GATA2-mediated mitotic bookmarking, we have fused GATA2 to a mitosis degradation (MD) domain, which promotes protein destruction at the mitosis-to-G1 transition (M-G1). Degradation of GATA2 at M-G1 impacts the reprogramming of human fibroblasts to hemogenic cells. To address the role of GATA2 at M-G1 in vivo, we have generated a mouse model with the MD domain inserted upstream the Gata2 gene. Remarkably, homozygous mice are lethal, phenocopying Gata2 null mice which die at the onset of definitive hematopoiesis, showing a deficit in hematopoietic stem and progenitor cells.These findings implicate GATA2 as a mitotic bookmarking factor and its critical role at M-G1 for definitive hematopoiesis. Overall, our study highlights a dependency on mitotic bookmarkers for in vivo lineage commitment.
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| 12. |
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| 13. |
- Argiropoulos, Bob, et al.
(författare)
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Linkage of Meis1 leukemogenic activity to multiple downstream effectors including Trib2 and Ccl3.
- 2008
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Ingår i: Experimental hematology. - : Elsevier BV. - 0301-472X. ; 36:7, s. 845-59
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: MEIS1, a HOX cofactor, collaborates with multiple HOX and NUP98-HOX fusion proteins to accelerate the onset of acute myeloid leukemia (AML) through largely unknown molecular mechanisms. MATERIALS AND METHODS: To further resolve these mechanisms, we conducted a structure-function analysis of MEIS1 and gene-expression profiling, in the context of NUP98-HOXD13 (ND13) leukemogenesis. RESULTS: We show, in a murine bone marrow transplantation model, that the PBX-interaction domain, the homeodomain, and the C-terminal domain of MEIS1, are all required for leukemogenic collaboration with ND13. In contrast, the N-terminal domain of MEIS1 is dispensable for collaboration with ND13, but is required for Flt3 upregulation, indicating additional roles for MEIS1 in induction of leukemia independent of alterations in Flt3 expression. Gene-expression profiling of a cloned ND13 preleukemic cell line transduced with wild-type or Meis1 mutant forms revealed deregulation of multiple genes, including a set not previously implicated as MEIS1 targets. Chromatin immunoprecipitation revealed the in vivo occupancy of MEIS1 on regulatory sequences of Trib2, Flt3, Dlk1, Ccl3, Ccl4, Pf4, and Rgs1. Furthermore, engineered overexpression of Trib2 complements ND13 to induce AML while Ccl3 potentiates the repopulating ability of ND13. CONCLUSION: This study shows that Meis1-induced leukemogenesis with ND13 can occur in the absence of Flt3 upregulation and reveals the existence of other pathways activated by MEIS1 to promote leukemia.
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| 14. |
- Askmyr, Maria, et al.
(författare)
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Low-dose busulphan conditioning and neonatal stem cell transplantation preserves vision and restores hematopoiesis in severe murine osteopetrosis.
- 2009
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Ingår i: Experimental Hematology. - : Elsevier BV. - 1873-2399 .- 0301-472X. ; 37, s. 302-308
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Infantile malignant osteopetrosis is a fatal disease caused by lack of functional osteoclasts. In most of patients, TCIRG1, encoding a subunit of a proton pump essential for bone resorption, is mutated. Osteopetrosis leads to bone marrow failure and blindness due to optic nerve compression. Oc/oc mice have a deletion in Tcirg1 and die around 3 to 4 weeks, but can be rescued by neonatal stem cell transplantation (SCT) after irradiation conditioning. However, as irradiation of neonatal mice results in retinal degeneration, we wanted to investigate whether conditioning with busulphan prior to SCT can lead to preservation of vision and reversal of osteopetrosis in the oc/oc mouse model. MATERIALS AND METHODS: Pregnant dams were conditioned with busulphan and their litters transplanted with 1 x 10(6) normal lineage-depleted bone marrow cells intravenously or intraperitoneally. Mice were followed in terms of survival and engraftment level, as well as with peripheral blood lineage analysis, bone and eye histopathology and a visual-tracking drum test to assess vision. RESULTS: Busulphan at 15 mg/kg was toxic to oc/oc mice. However, six of seven oc/oc mice conditioned with busulphan 7.5 mg/kg survived past the normal lifespan with 10% engraftment, correction of the skeletal phenotype, and normalization of peripheral blood lineages. Busulphan, in contrast to irradiation, did not have adverse effects on the retina as determined by histopathology, and 8 weeks after transplantation control and oc/oc mice retained their vision. CONCLUSION: Low-dose busulphan conditioning and neonatal SCT leads to prolonged survival of oc/oc mice, reverses osteopetrosis and prevents blindness even at low engraftment levels.
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| 15. |
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| 16. |
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| 17. |
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| 18. |
- Billing, Matilda, et al.
(författare)
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A network including TGFβ/Smad4, Gata2 and p57 regulates proliferation of mouse hematopoietic progenitor cells.
- 2016
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Ingår i: Experimental Hematology. - : Elsevier BV. - 1873-2399 .- 0301-472X. ; 44:5, s. 399-409
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Tidskriftsartikel (refereegranskat)abstract
- Transforming growth factor-β (TGFβ) is a potent inhibitor of hematopoietic stem and progenitor cell proliferation. However, the precise mechanism for this effect is unknown. Here, we have identified the transcription factor Gata2, previously described as an important regulator of hematopoietic stem cell (HSC) function, as an early and direct target gene for TGFβ-induced Smad signaling in hematopoietic progenitor cells. We also report that Gata2 is involved in mediating a significant part of the TGFβ response in primitive hematopoietic cells. Interestingly, the cell cycle regulator and TGFβ signaling effector molecule p57 was found to be upregulated as a secondary response to TGFβ. We observed Gata2 binding upstream of the p57 genomic locus, and importantly loss of Gata2 abolished TGFβ-stimulated induction of p57 as well as the resulting growth arrest of hematopoietic progenitors. Our results connect key molecules involved in HSC self-renewal and reveal a functionally relevant network regulating proliferation of primitive hematopoietic cells.
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| 19. |
- Billing, Matilda, et al.
(författare)
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Signaling via Smad2 and Smad3 is dispensable for adult murine hematopoietic stem cell function in vivo
- 2017
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Ingår i: Experimental Hematology. - : Elsevier BV. - 0301-472X.
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Tidskriftsartikel (refereegranskat)abstract
- Transforming growth factor-β (TGFβ) is a member of a large family of polypeptide growth factors. TGFβ signals mainly through the intracellular proteins Smad2 and Smad3, which are highly similar in amino acid sequence identity. A number of studies have shown that these proteins, dependent on context, have distinct roles in the TGFβ signaling pathway. TGFβ is one of the most potent inhibitors of hematopoietic stem and progenitor cell proliferation in vitro, but its role in hematopoiesis in vivo is still being determined. To circumvent possible redundancies at the receptor level and to address specifically the role of the Smad circuitry downstream of TGFβ and activin in hematopoiesis, we studied the effect of genetically deleting both Smad2 and Smad3 in adult murine hematopoietic cells. Indeed, TGFβ signaling is impaired in vitro in primitive bone marrow (BM) cells of Smad2 and Smad3 single knockout models. However, blood parameters appear normal under steady state and in the transplantation setting. Interestingly, upon deletion of both Smad2 and Smad3 in vivo, mice quickly develop a lethal inflammatory disease, suggesting that activin/TGFβ signaling is crucial for immune cell homeostasis in the adult context. Furthermore, concurrent deletion of Smad2 and Smad3 in BM cells in immune-deficient nude mice did not result in any significant alterations of the hematopoietic system. Our findings suggest that Smad2 and Smad3 function to mediate crucial aspects of the immunoregulatory properties of TGFβ, but are dispensable for any effect that TGFβ has on primitive hematopoietic cells in vivo.
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| 20. |
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| 21. |
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| 22. |
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| 23. |
- Borssen, Magnus, et al.
(författare)
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hTERT promoter methylation and telomere length in childhood acute lymphoblastic leukemia-associations with immunophenotype and cytogenetic subgroup
- 2011
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Ingår i: Experimental Hematology. - New York : Elsevier. - 0301-472X .- 1873-2399. ; 39:12, s. 1144-1151
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Tidskriftsartikel (refereegranskat)abstract
- Telomere maintenance, important for long-term cell survival and malignant transformation, is directed by a multitude of factors, including epigenetic mechanisms, and has been implicated in outcomes for patients with leukemia. In the present study, the objective was to investigate the biological and clinical significance of telomere length and promoter methylation of the human telomerase reverse transcriptase gene in childhood acute lymphoblastic leukemia. A cohort of 169 childhood acute lymphoblastic leukemias was investigated for telomere length, human telomerase reverse transcriptase gene promoter methylation status, genomic aberrations, immunophenotype, and clinical outcomes. Methylation of the core promoter of the human telomerase reverse transcriptase (hTERT) gene was demonstrated in 24% of diagnostic samples, with a significant difference between B-cell precursor (n = 130) and T-cell acute lymphoblastic leukemia (ALL) (n = 17) cases (18% and 72%, respectively; p < 0.001). No remission sample demonstrated hTERT promoter methylation (n = 40). Within the B-cell precursor group, t(12;21)(p13;q22) [ETV6/RUNX1] cases (n = 19) showed a much higher frequency of hTERT methylation than high-hyperdiploid (51 61 chromosomes) ALL (n = 44) (63% and 7%, respectively; p < 0.001). hTERT messenger RNA levels were negatively associated with methylation status and, in the t(12;21) group, methylated cases had shorter telomeres (p = 0.017). In low-risk B-cell precursor patients (n = 101), long telomeres indicated a worse prognosis. The collected data from the present study indicate that the telomere biology in childhood ALL has clinical implications and reflects molecular differences between diverse ALL subgroups. (C) 2011 ISEH - Society for Hematology and Stem Cells. Published by Elsevier Inc.
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| 24. |
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| 25. |
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| 26. |
- Cammenga, Jörg
(författare)
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Of gains and losses : SAMD9/SAMD9L and monosomy 7 in myelodysplastic syndrome
- 2024
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Ingår i: Experimental Hematology. - 0301-472X. ; 134
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Forskningsöversikt (refereegranskat)abstract
- SAMD9 and SAMD9L are two interferon-regulated genes located adjacent to each other on chromosome 7q21.2. Germline gain-of-function (GL GOF) mutations in SAMD9/SAMD9L are the genetic cause of MIRAGE syndrome, ataxia-pancytopenia (ATXPC) syndrome, myeloid leukemia syndrome with monosomy 7 (MLSM7), refractory cytopenia of childhood (RCC), transient monosomy 7 in children, SAMD9L-associated autoinflammatory disease (SAAD), and a proportion of inherited aplastic anemia and bone marrow failure syndromes. The myeloid neoplasms associated with GL GOF SAMD9/SAMD9L mutations have been included in the World Health Organization (WHO) 2022 classification. The discovery of SAMD9/SAMD9L-related diseases has revealed some interesting pathobiological mechanisms, such as a high rate of primary somatic compensation, with one of the mechanisms being (transient) monosomy 7 a mechanism also described as “adaption by aneuploidy.” The somatic compensation in the blood can complicate the diagnosis of SAMD9/SAMD9L-related disease when relying on hematopoietic tissues for diagnosis. Recently, GL loss-of function (LOF) mutations have been identified in older individuals with myeloid malignancies in accordance with a mouse model of SAMD9L loss that develops a myelodysplastic syndrome (MDS)-like disease late in life. The discovery of SAMD9/SAMD9L-associated syndromes has resulted in a deeper understanding of the genetics and biology of diseases/syndromes that were previously oblivious and thought to be unrelated to each other. Besides giving an overview of the literature, this review wants to also provide some practical guidance for the classification of SAMD9/SAMD9L variants that is complicated by the nonrecurrent nature of these mutations but also by the fact that both GL GOF, as well as loss-of-function mutations, have been identified.
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| 27. |
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| 28. |
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| 29. |
- Chou, Song, et al.
(författare)
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Fetal hepatic progenitors support long-term expansion of hematopoietic stem cells
- 2013
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Ingår i: Experimental Hematology. - : Elsevier BV. - 1873-2399 .- 0301-472X. ; 41:5, s. 479-490
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Tidskriftsartikel (refereegranskat)abstract
- We have developed a coculture system that establishes DLK+ fetal hepatic progenitors as the authentic supportive cells for expansion of hematopoietic stem (HSCs) and progenitor cells. In 1-week cultures supplemented with serum and supportive cytokines, both cocultured DLK+ fetal hepatic progenitors and their conditioned medium supported rapid expansion of hematopoietic progenitors and a small increase in HSC numbers. In 2- and 3-week cultures DLK+ cells, but not their conditioned medium, continuously and significantly (>20-fold) expanded both hematopoietic stem and progenitor cells. Physical contact between HSCs and DLK+ cells was crucial to maintaining this long-term expansion. Similar HSC expansion (approximately sevenfold) was achieved in cocultures using a serum-free, low cytokine- containing medium. In contrast, DLK- cells are incapable of expanding hematopoietic cells, demonstrating that hepatic progenitors are the principle supportive cells for HSC expansion in the fetal liver. (C) 2013 ISEH - Society for Hematology and Stem Cells. Published by Elsevier Inc.
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| 30. |
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| 31. |
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| 32. |
- Dahl, Maria, et al.
(författare)
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Bone marrow transplantation without myeloablative conditioning in a mouse model for Diamond-Blackfan anemia corrects the disease phenotype
- 2021
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Ingår i: Experimental Hematology. - : Elsevier BV. - 0301-472X. ; 99, s. 2-53
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Tidskriftsartikel (refereegranskat)abstract
- Diamond-Blackfan anemia (DBA) is a congenital erythroid hypoplasia caused by a functional haploinsufficiency of genes coding for ribosomal proteins. Among these genes, the ribosomal protein S19 (RPS19) gene is the most frequently mutated. Previously, a mouse model deficient in RPS19 was developed by our laboratory, which recapitulates the hematopoietic disease phenotype by manifesting pathologic features and clinical symptoms of DBA. Characterization of this model revealed that chronic RPS19 deficiency leads to exhaustion of hematopoietic stem cells and subsequent bone marrow (BM) failure. In this study, we evaluated a nonmyeloablative conditioning protocol for BM transplants in RPS19-deficient mice by transplanting wild-type BM cells to RPS19-deficient recipients given no conditioning or sublethal doses of irradiation before transplant. We describe full correction of the hematopoietic phenotype in mice given sublethal doses of irradiation, as well as in animals completely devoid of any preceding irradiation. In comparison, wild-type animals receiving the same preconditioning regimen and number of transplanted cells exhibited significantly lower engraftment levels. Thus, robust engraftment and repopulation of transplanted cells can be achieved in reduced-intensity conditioned RPS19-deficient recipients. As gene therapy studies with autologous gene-corrected hematopoietic stem cells are emerging, we propose the results described here can guide determination of the level of conditioning for such a protocol in RPS19-deficient DBA. On the basis of our findings, a relatively mild conditioning strategy would plausibly be sufficient to achieve sufficient levels of engraftment and clinical success.
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| 33. |
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| 34. |
- Eliasson, Pernilla, et al.
(författare)
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Hypoxia mediates low cell-cycle activity and increases the proportion of long-term reconstituting hematopoietic stem cells during in vitro culture
- 2010
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Ingår i: Experimental Hematology. - : Elsevier. - 0301-472X .- 1873-2399. ; 38:4, s. 301-310
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Tidskriftsartikel (refereegranskat)abstract
- Objective. Recent evidence suggests that hematopoietic stem cells (HSCs) in the bone marrow (BM) are located in areas where the environment is hypoxic. Although previous studies have demonstrated positive effects by hypoxia, its role in HSC maintenance has not been fully elucidated, neither has the molecular mechanisms been delineated. Here, we have investigated the consequence of in vitro incubation of HSCs in hypoxia prior to transplantation and analyzed the role of hypoxia-inducible factor (HIF)-1 alpha. Materials and Methods. HSC and progenitor populations isolated from mouse BM were cultured in 20% or 1% O-2, and analyzed for effects on cell cycle, expression of cyclin-dependent kinase inhibitors genes, and reconstituting ability to lethally irradiated mice. The involvement of HIF-1 alpha was studied using methods of protein stabilization and gene silencing. Results. When long-term FLT3(-)CD34(-)Lin(-)Sca-1(+)c-Kit(+) (LSK) cells were cultured in hypoxia, cell numbers were significantly reduced in comparison to normoxia. This was due to a decrease in proliferation and more cells accumulating in G(0). Moreover, the proportion of HSCs with long-term engraftment potential was increased. Whereas expression of the cyclin-dependent kinase inhibitor genes p21(cip1), p27(Kip1), and p57(Kip2) increased in LSK cells by hypoxia, only p21(cip1) was upregulated in FLT3(-)CD34(-)LSK cells. We could demonstrate that expression of p27(KiP1) and p57(Kip2) was dependent of HIF-1 alpha. Surprisingly, overexpression of constitutively active HIF-1 alpha or treatment with the HIF stabilizer agent FG-4497 led to a reduction in HSC reconstituting ability. Conclusions. Our results imply that hypoxia, in part via HIF-1 alpha, maintains HSCs by decreasing proliferation and favoring quiescence.
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| 35. |
- Eriksson, Anna, et al.
(författare)
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Epigenetic aberrations in acute myeloid leukemia : Early key events during leukemogenesis
- 2015
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Ingår i: Experimental Hematology. - : Elsevier BV. - 0301-472X .- 1873-2399. ; 43:8, s. 609-624
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Tidskriftsartikel (refereegranskat)abstract
- As a result of the introduction of new sequencing technologies, the molecular landscape of acute myeloid leukemia (AML) is rapidly evolving. From karyotyping, which detects only large genomic aberrations of metaphase chromosomes, we have moved into an era when sequencing of each base pair allows us to define the AML genome at highest resolution. This has revealed a new complex landscape of genetic aberrations where addition of mutations in epigenetic regulators has been one of the most important contributions to the understanding of the pathogenesis of AML. These findings, together with new insights into epigenetic mechanisms, have placed dysregulated epigenetic mechanisms at the forefront of AML development. Not only have several new mutations in genes directly involved in epigenetic regulatory mechanisms been discovered, but also previously well-known gene fusions have been found to exert aberrant effects through epigenetic mechanisms. In addition, mutations in epigenetic regulators such as DNMT3A, TET2, and ASXL1 have recently been found to be the earliest known events during AML evolution and to be present as preleukemic lesions before the onset of AML. In this article, we review epigenetic changes in AML also in relation to what is known about their mechanism of action and their prognostic role.
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| 36. |
- Erslev, A. J., et al.
(författare)
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The biogenesis of erythropoietin
- 1980
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Ingår i: Experimental Hematology. - 0301-472X .- 1873-2399. ; 8:Suppl 8, s. 1-13
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Tidskriftsartikel (refereegranskat)abstract
- Aerobic living demands a constant supply of oxygen at the cellular mitochondrial level. Numerous interlocking feedback mechanisms insure the constancy of this supply by adapting the supply lines to changes in the intra and extracellular milieu. Among these mechanisms is the feedback circuit which, triggered by an intracellular decrease in oxygen supply, initiates the production of a polypeptide hormone, erythropoietin, which in turn augments the production of an oxygen carrier, the hemoglobin-containing red cell. The biogenesis of this hormone is an important biologic process which is being studied intensively and slowly unravelled.
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| 37. |
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| 38. |
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| 39. |
- Ferreira, Alexandra Gabriela, et al.
(författare)
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Restoring the immunogenicity of cancer cells with dendritic cell reprogramming
- 2021
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Ingår i: Experimental Hematology. - : Elsevier BV. - 1873-2399 .- 0301-472X. ; 100:Suppl, s. 72-72
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Konferensbidrag (refereegranskat)abstract
- An important hallmark of cancer is the ability to evade the immune system. Genetic mutations may result in the accumulation of tumor antigens, however, downregulation of antigen presentation in tumor cells results in decreased immunogenicity and immune surveillance evasion. Recently, we demonstrated that enforced expression of PU.1, IRF8 and BATF3 (PIB) imposes a conventional dendritic cell type 1 (cDC1) fate in fibroblasts by direct cell reprogramming. As such, we hypothesise that a similar combination of transcription factors can reprogram cancer cells into antigen presenting cells.Here, we show that expression of PIB factors is sufficient to induce hematopoietic and cDC1 markers in the mouse melanoma and lung cancer cell lines B16 and 3LL. We further show that reprogramming restores the expression of antigen presentation molecules (MHC-II, MHC-I and B2M) at cancer cell surface. This is accompanied by the activation of the co-stimulatory molecules CD80 and CD86. This reprogrammed tumor antigen presenting cell (tumor-APC) phenotype is specified gradually within the course of 9 days. PIB overwrites the cancer transcriptional program imposing global antigen presentation and cDC1 gene signatures. Functionally, tumor-APCs secrete inflammatory cytokines such as IL-12, IL-6, CXCL10 and type 1 interferons. After reprogramming they also acquire the capacity to uptake and process proteins as well as dead cells. Importantly, tumor-APCs directly prime antigen-specific naïve CD8+ T-cells after antigen loading. Finally, tumor-APCs are capable to show endogenous antigens to T cells and become prone to T cell mediated cell killing.Our approach combines cDC1’s antigen processing and presenting abilities with the endogenous generation of tumor antigens, and serves as a platform for the development of novel immunotherapies based on endowed antigen presentation in cancer cells.
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| 40. |
- Flygare, Johan, et al.
(författare)
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Gene therapy of Diamond Blackfan anemia CD34(+) cells leads to improved erythroid development and engraftment following transplantation.
- 2008
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Ingår i: Experimental Hematology. - : Elsevier BV. - 1873-2399 .- 0301-472X. ; 36, s. 1428-1435
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Diamond-Blackfan anemia (DBA) is a rare congenital hypoplastic anemia caused by mutations in ribosomal protein (RP) genes. Our aim is to develop gene therapy for DBA patients with mutations in RPS19. We previously demonstrated that RPS19 gene transfer partially corrects erythroid development in vitro. In this study, we asked if RPS19 gene transfer corrects erythroid development in unsorted cells transplanted to immunodeficient mice and if the RPS19-corrected fraction has a proliferative advantage after transplantation. We further determined if high level of RPS19 expression is required for correction. MATERIAL AND METHODS: Mobilized peripheral blood CD34(+) cells were transduced by oncoretroviral vector particles pseudotyped with the feline endogenous retrovirus envelope. Vectors containing two different promoters with different RPS19 transgene expression levels were compared. Transduced cells were transplanted to immunocompromised nonobese diabetic/severe combined immunodeficient-beta2 microglobulin null mice in order to assess therapeutic effects of RPS19 gene transfer in vivo. RESULTS: We show that correction of erythroid development requires high RPS19 expression. The corrected fraction of unselected DBA cells have a survival advantage in vivo, suggesting that successful gene therapy may only require correction of a fraction of the patient cells. CONCLUSION: Our findings are fundamental for development of clinical gene therapy for DBA because they demonstrate increased engraftment of RPS19-transduced cells without selection of gene-corrected cells prior to transplantation, an essential prelude to studying long-term therapeutic effects in emerging animal models for DBA.
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| 41. |
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| 42. |
- Glimelius, Ingrid, et al.
(författare)
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The effect of Eosinophil cationic protein (ECP) on Hodgkin lymphoma cell lines
- 2011
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Ingår i: Experimental Hematology. - : Elsevier BV. - 0301-472X .- 1873-2399. ; 39:8, s. 850-858
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Tidskriftsartikel (refereegranskat)abstract
- Background In classical Hodgkin lymphoma (HL), many eosinophils in tumour tissue indicate poor prognosis, probably caused by stimulation of the tumour cells, the Hodgkin Reed Sternberg (HRS) cells. However, eosinophils are primarily known for their role in innate immunity, where one function is to secrete the toxic substances eosinophil cationic protein (ECP), and eosinophil protein X (EPX). The aim of this study was to investigate the effects of ECP on HRS cells in vitro.Method The fluorometric microculture cytotoxicity-assay (FMCA) measured survival index (SI) of cells from the HL cell lines HDLM-2, KMH2, and L428 after incubation with ECP or EPX. The gene products of a coding ECP polymorphism, ECP97arg and ECP97thr, and ECPs, with different levels of glycosylation were investigated. Flow cytometry was used to monitor the effects of ECP on markers of cell death.Results A concentration dependent reduction of SI was seen after ECP treatment. For the B-cell derived cell lines, KMH2 and L428, ECP was cytotoxic with a dose response relationship similar to a previously investigated small-cell lung cancer cell-line. In contrast, for HDLM-2, which is a cell line of T-cell origin, the cytotoxicity was even more pronounced at the lowest concentrations tested, and then reached a plateau at about 0.018µM. At a concentration of 0.14µM of ECP, an SI of 71%±1.9 was recorded for HDLM-2, which did not accentuate despite higher concentrations of ECP. ECP97arg and ECP97thr displayed similar cytotoxicity, and the level of glycosylation did not affect cytotoxicity for HDLM-2, in contrast to the small-cell lung cancer cell-line. For EPX, no or very limited reduction in SI was seen, compared to ECP (p<0.001). The majority of cells that died from ECP (the HDLM-2 cell line) were PI positive, and only a few were annexin V positive.Conclusions ECP is cytotoxic for HRS cells, but heterogeneity between cell lines was seen. The two cell lines of B-cell origin, KMH2 and L428, were sensitive to high ECP concentrations, but for HDLM-2, of T-cell origin, the cytotoxicity reached a plateau at higher concentrations. Thus, even at presumably high concentrations, ECP can be present around HRS cells without eradicating all cells.
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| 43. |
- Gundry, Michael C., et al.
(författare)
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Technical considerations for the use of CRISPR/Cas9 in hematology research
- 2017
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Ingår i: Experimental Hematology. - : Elsevier BV. - 0301-472X.
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Tidskriftsartikel (refereegranskat)abstract
- The hematopoietic system is responsible for transporting oxygen and nutrients, fighting infections, and repairing tissue damage. Hematopoietic system dysfunction therefore causes a range of serious health consequences. Lifelong hematopoiesis is maintained by repopulating multipotent hematopoietic stem cells (HSCs) that replenish shorter-lived, mature blood cell types. A prokaryotic mechanism of immunity, the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Cas9 nuclease system, has been recently "repurposed" to mutate mammalian genomes efficiently and in a sequence-specific manner. The application of this genome-editing technology to hematology has afforded new approaches for functional genomics and even the prospect of "correcting" dysfunctional HSCs in the treatment of serious genetic hematological diseases. In this Perspective, we provide an overview of three recent CRISPR/Cas9 methods in hematology: gene disruption, gene targeting, and saturating mutagenesis. We also summarize the technical considerations and advice provided during the May 2017 International Society of Experimental Hematology New Investigator Committee webinar on the same topic.
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- Hidalgo, Isabel, et al.
(författare)
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Bmi1 induction protects hematopoietic stem cells against pronounced long-term hematopoietic stress
- 2022
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Ingår i: Experimental Hematology. - : Elsevier BV. - 1873-2399 .- 0301-472X. ; 109, s. 35-44
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Tidskriftsartikel (refereegranskat)abstract
- The Polycomb complex protein Bmi1 is regarded as a master regulator of hematopoietic stem cells (HSCs). In the blood system, HSCs express Bmi1 most abundantly and Bmi1 expression vanes as cells differentiate. Furthermore, Bmi1 has been found overexpressed in several hematologic cancers. Most studies exploring the normal role of Bmi1 in HSC biology have utilized loss-of-function models, which have established Bmi1 as an important regulator for HSC maintenance. Additionally, gain-of-function studies using retroviral and lentiviral approaches have observed increased self-renewal of Bmi-1 transduced HSCs. However, the clinical and biological relevance of such studies are typically hampered by uncontrolled transgenic integration and supraphysiological expression levels. Here, we developed a novel Tetracycline-inducible gain-of-function Bmi1 (iBmi1) transgenic mouse model. We find that Bmi1 induction had minor, if any, effects on steady-state hematopoiesis or following 5-fluorouracil-induced cytostatic stress. On the contrary, secondary transplantation of iBmi1 HSCs into wild type recipients resulted in remarkable increases of HSC numbers and chimerism levels. These data, in concert with previous loss-of-function studies, suggest that while endogenous Bmi1 levels are required and sufficient for normal HSC maintenance, the stabilization of these levels over time protects HSC from transplantation-associated stress.
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