| 1. |
- 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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| 2. |
- Debnath, Shubhranshu
(författare)
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Development of novel therapies for Diamond-Blackfan Anemia
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Diamond-Blackfan anemia is a congenital erythroid hypoplasia manifesting early inlife. In at least 60-70% of cases, DBA is caused by a functional haploinsufficiencyof genes encoding for ribosomal proteins. Approximately, 25% percent of patientshave mutations in the gene encoding ribosomal protein S19 (RPS19). Thehematological profile of DBA patients shows macrocytic anemia withreticulocytopenia, normal or decreased levels of neutrophils and variable plateletscounts. DBA patients also exhibit various non-hematological manifestations suchas physical abnormalities and cancer predisposition. Corticosteroids are the maintherapeutic option in DBA. Around 80% of the patients initially respond tocorticosteroids, but only 40% of patients sustain the therapeutic response and theremaining 40% of patients need chronic blood transfusion. Twenty% of patients gointo spontaneous remission and maintain an acceptable hemoglobin level withouttherapeutic intervention. The only curative treatment available for DBA patients isallogeneic bone marrow transplantation.This thesis focuses on understanding the disease pathogenesis and development ofnovel therapies for DBA. In Article-I we sought to understand the physiologicalrelevance of the 5S RNP-Mdm2-p53 pathway for generation of the erythroid defectupon RPS19 deficiency. In Article-II we aimed to evaluate the therapeutic effect ofthe amino acid L-leucine in the treatment of DBA. In Article-III and IV we examinethe feasibility of RPS19 gene therapy in the treatment of RPS19 deficient DiamondBlackfan Anemia.In summary, this work focuses on basic and translational research towardsevaluating novel therapies and understanding molecular mechanisms for DBA.
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| 3. |
- Debnath, Shubhranshu, et al.
(författare)
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Lentiviral Vectors with Cellular Promoters Correct Anemia and Lethal Bone Marrow Failure in a Mouse Model for Diamond-Blackfan Anemia
- 2017
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Ingår i: Molecular Therapy. - : Elsevier BV. - 1525-0016. ; 25:8, s. 1805-1814
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Tidskriftsartikel (refereegranskat)abstract
- Diamond-Blackfan anemia is a congenital erythroid hypoplasia and is associated with physical malformations and a predisposition to cancer. Twenty-five percent of patients with Diamond-Blackfan anemia have mutations in a gene encoding ribosomal protein S19 (RPS19). Through overexpression of RPS19 using a lentiviral vector with the spleen focus-forming virus promoter, we demonstrated that the Diamond-Blackfan anemia phenotype can be successfully treated in Rps19-deficient mice. In our present study, we assessed the efficacy of a clinically relevant promoter, the human elongation factor 1α short promoter, with or without the locus control region of the β-globin gene for treatment of RPS19-deficient Diamond-Blackfan anemia. The findings demonstrate that these vectors rescue the proliferation defect and improve erythroid development of transduced RPS19-deficient bone marrow cells. Remarkably, bone marrow failure and severe anemia in Rps19-deficient mice was cured with enforced expression of RPS19 driven by the elongation factor 1α short promoter. We also demonstrate that RPS19-deficient bone marrow cells can be transduced and these cells have the capacity to repopulate bone marrow in long-term reconstituted mice. Our results collectively demonstrate the feasibility to cure RPS19-deficient Diamond-Blackfan anemia using lentiviral vectors with cellular promoters that possess a reduced risk of insertional mutagenesis. Diamond-Blackfan anemia is a congenital erythroid hypoplasia. Twenty-five percent of patients have mutations in a gene encoding ribosomal protein S19. Using an RPS19-deficient mouse model, Debnath et al. demonstrate the feasibility to cure RPS19-deficient Diamond-Blackfan anemia by means of lentiviral vectors with cellular promoters that possess a reduced risk of insertional mutagenesis.
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| 4. |
- Jaako, Pekka, et al.
(författare)
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Dietary L-leucine improves the anemia in a mouse model for Diamond-Blackfan anemia.
- 2012
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Ingår i: Blood. - : American Society of Hematology. - 1528-0020 .- 0006-4971. ; 120:11, s. 2225-2228
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Tidskriftsartikel (refereegranskat)abstract
- Diamond-Blackfan anemia (DBA) is a congenital erythroid hypoplasia caused by a functional haploinsufficiency of genes encoding for ribosomal proteins. Recently, a case study reported a patient who became transfusion-independent in response to treatment with the amino acid L-leucine. Therefore, we have validated the therapeutic effect of L-leucine using our recently generated mouse model for RPS19-deficient DBA. Administration of L-leucine significantly improved the anemia in Rps19-deficient mice (19 % improvement in hemoglobin concentration; 18% increase in the number of erythrocytes), increased the bone marrow cellularity and alleviated stress hematopoiesis. Furthermore, the therapeutic response to L-leucine appeared specific for Rps19-deficient hematopoiesis and was associated with downregulation of p53 activity. Our study supports the rationale for clinical trials of L-leucine as a therapeutic agent for DBA.
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| 5. |
- Jaako, Pekka, et al.
(författare)
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Disruption of the 5S RNP-Mdm2 interaction significantly improves the erythroid defect in a mouse model for Diamond-Blackfan anemia.
- 2015
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Ingår i: Leukemia. - : Springer Science and Business Media LLC. - 1476-5551 .- 0887-6924. ; 29:11, s. 2221-2229
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Tidskriftsartikel (refereegranskat)abstract
- Diamond-Blackfan anemia (DBA) is a congenital erythroid hypoplasia caused by haploinsufficiency of genes encoding ribosomal proteins (RPs). Perturbed ribosome biogenesis in DBA has been shown to induce a p53-mediated ribosomal stress response. However, the mechanisms of p53 activation and its relevance for the erythroid defect remain elusive. Previous studies have indicated that activation of p53 is caused by the inhibition of Mdm2, the main negative regulator of p53, by the 5S ribonucleoprotein particle (RNP). Meanwhile, it is not clear whether this mechanism solely mediates the p53-dependent component found in DBA. To approach this question, we crossed our mouse model for RPS19-deficient DBA with Mdm2(C305F) knock-in mice that have a disrupted 5S RNP-Mdm2 interaction. Upon induction of the Rps19 deficiency, Mdm2(C305F) reversed the p53 response and improved expansion of hematopoietic progenitors in vitro, and ameliorated the anemia in vivo. Unexpectedly, disruption of the 5S RNP-Mdm2 interaction also led to selective defect in erythropoiesis. Our findings highlight the sensitivity of erythroid progenitor cells to aberrations in p53 homeostasis mediated by the 5S RNP-Mdm2 interaction. Finally, we provide evidence indicating that physiological activation of the 5S RNP-Mdm2-p53 pathway may contribute to functional decline of the hematopoietic system in a cell-autonomous manner over time.Leukemia accepted article preview online, 19 May 2015. doi:10.1038/leu.2015.128.
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| 6. |
- Jaako, Pekka, et al.
(författare)
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Gene therapy cures the anemia and lethal bone marrow failure in mouse model for RPS19-deficient Diamond-Blackfan anemia.
- 2014
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Ingår i: Haematologica. - : Ferrata Storti Foundation (Haematologica). - 1592-8721 .- 0390-6078. ; 99:12, s. 1792-1798
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Tidskriftsartikel (refereegranskat)abstract
- Diamond-Blackfan anemia is a congenital erythroid hypoplasia caused by functional haploinsufficiency of genes encoding ribosomal proteins. Mutations involving the ribosomal protein S19 gene are detected in 25 % of patients. Enforced expression of ribosomal protein S19 improves the overall proliferative capacity, erythroid colony-forming potential and erythroid differentiation of hematopoietic progenitors from ribosomal protein S19-deficient patients in vitro and in vivo following xenotransplantation. However, studies using animal models are needed to assess the therapeutic efficacy and safety of the viral vectors. In the present study we have validated the therapeutic potential of gene therapy using mouse models for ribosomal protein S19-deficient Diamond-Blackfan anemia. Using lentiviral gene transfer we demonstrate that enforced expression of ribosomal protein S19 cures the anemia and lethal bone marrow failure in recipients transplanted with ribosomal protein S19-deficient cells. Furthermore, gene-corrected ribosomal protein S19-deficient cells showed an increased pan-hematopoietic contribution over time compared to untransduced cells without signs of vector-mediated toxicity. Our study provides a proof of principle for the development of clinical gene therapy to cure ribosomal protein 19-deficient Diamond-Blackfan anemia.
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| 7. |
- Komorowska, Karolina, et al.
(författare)
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Hepatic Leukemia Factor Maintains Quiescence of Hematopoietic Stem Cells and Protects the Stem Cell Pool during Regeneration
- 2017
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Ingår i: Cell Reports. - : Elsevier BV. - 2211-1247. ; 21:12, s. 3514-3523
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Tidskriftsartikel (refereegranskat)abstract
- The transcription factor hepatic leukemia factor (HLF) is strongly expressed in hematopoietic stem cells (HSCs) and is thought to influence both HSC self-renewal and leukemogenesis. However, the physiological role of HLF in hematopoiesis and HSC function is unclear. Here, we report that mice lacking Hlf are viable with essentially normal hematopoietic parameters, including an intact HSC pool during steady-state hematopoiesis. In contrast, when challenged through transplantation, Hlf-deficient HSCs showed an impaired ability to reconstitute hematopoiesis and became gradually exhausted upon serial transplantation. Transcriptional profiling of Hlf-deficient HSCs revealed changes associated with enhanced cellular activation, and cell-cycle analysis demonstrated a significant reduction of quiescent HSCs. Accordingly, toxic insults targeting dividing cells completely eradicated the HSC pool in Hlf-deficient mice. In summary, our findings point to HLF as a critical regulator of HSC quiescence and as an essential factor for maintaining the HSC pool during regeneration. Komorowska et al. report that the transcription factor HLF is required to maintain hematopoietic stem cell (HSC) function during regeneration. Moreover, Hlf-deficient HSCs are less quiescent. In accordance with this, toxic insults targeting dividing cells completely eradicate the HSC pool in Hlf-deficient mice.
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| 8. |
- Liu, Yang, et al.
(författare)
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Successful gene therapy of Diamond-Blackfan anemia in a mouse model and human CD34+ cord blood hematopoietic stem cells using a clinically applicable lentiviral vector
- 2022
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Ingår i: Haematologica. - : Ferrata Storti Foundation (Haematologica). - 1592-8721 .- 0390-6078. ; 107:2, s. 446-456
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Tidskriftsartikel (refereegranskat)abstract
- Diamond-Blackfan anemia (DBA) is an inherited bone marrow failure disorder in which pure red blood cell aplasia is associated with physical malformations and a predisposition to cancer. Twentyfive percent of patients with DBA have mutations in a gene encoding ribosomal protein S19 (RPS19). Our previous proof-of-concept studies demonstrated that DBA phenotype could be successfully treated using lentiviral vectors in Rps19-deficient DBA mice. In our present study, we developed a clinically applicable single gene, self-inactivating lentiviral vector, containing the human RPS19 cDNA driven by the human elongation factor 1a short promoter, which can be used for clinical gene therapy development for RPS19-deficient DBA. We examined the efficacy and safety of the vector in a Rps19-deficient DBA mouse model and in human primary RPS19-deficient CD34+ cord blood cells. We observed that transduced Rps19-deficient bone marrow cells could reconstitute mice long-term and rescue the bone marrow failure and severe anemia observed in Rps19-deficient mice, with a low risk of mutagenesis and a highly polyclonal insertion site pattern. More importantly, the vector can also rescue impaired erythroid differentiation in human primary RPS19-deficient CD34+ cord blood hematopoietic stem cells. Collectively, our results demonstrate the efficacy and safety of using a clinically applicable lentiviral vector for the successful treatment of Rps19-deficient DBA in a mouse model and in human primary CD34+ cord blood cells. These findings show that this vector can be used to develop clinical gene therapy for RPS19-deficient DBA patients.
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| 9. |
- Subramaniam, Agatheeswaran, et al.
(författare)
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Lysine-specific demethylase 1A (LSD1) restricts ex vivo propagation of human HSCs and is a target of UM171
- 2020
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Ingår i: Blood. - : American Society of Hematology. - 1528-0020 .- 0006-4971. ; 136:19, s. 2151-2161
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Tidskriftsartikel (refereegranskat)abstract
- Culture conditions in which hematopoietic stem cells (HSCs) can be expanded for clinical benefit are highly sought after. Here, we report that inhibition of the epigenetic regulator Lysine-specific histone demethylase 1A (LSD1) induces a rapid expansion of human cord blood derived CD34+ cells and promotes in vitro propagation of long-term repopulating HSCs by preventing differentiation. The phenotype and molecular characteristics of cells treated with LSD1 inhibitors were highly similar to cells treated with UM171, an agent promoting expansion of HSCs through undefined mechanisms, and currently tested in clinical trials. Strikingly, we found that LSD1 as well as other members of the LSD1 containing chromatin remodeling complex CoREST are rapidly poly-ubiquitinated and degraded upon UM171 treatment. CRISPR/Cas9 depletion of the CoREST core member, RCOR1, resulted in expansion of CD34+ cells similar to LSD1 inhibition and UM171. Taken together, LSD1 and CoREST restrict HSC expansion, and are principal targets of UM171, forming a mechanistic basis for the HSC promoting activity of UM171.
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