| 1. |
- 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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| 2. |
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| 3. |
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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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eIF6 rebinding dynamically couples ribosome maturation and translation.
- 2022
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Ingår i: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Protein synthesis is a cyclical process consisting of translation initiation, elongation, termination and ribosome recycling. The release factors SBDS and EFL1-both mutated in the leukemia predisposition disorder Shwachman-Diamond syndrome - license entry of nascent 60S ribosomal subunits into active translation by evicting the anti-association factor eIF6 from the 60S intersubunit face. We find that in mammalian cells, eIF6 holds all free cytoplasmic 60S subunits in a translationally inactive state and that SBDS and EFL1 are the minimal components required to recycle these 60S subunits back into additional rounds of translation by evicting eIF6. Increasing the dose of eIF6 in mice in vivo impairs terminal erythropoiesis by sequestering post-termination 60S subunits in the cytoplasm, disrupting subunit joining and attenuating global protein synthesis. These data reveal that ribosome maturation and recycling are dynamically coupled by a mechanism that is disrupted in an inherited leukemia predisposition disorder.
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| 7. |
- 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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| 8. |
- Jaako, Pekka, et al.
(författare)
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Mice with ribosomal protein S19 deficiency develop bone marrow failure and symptoms like patients with Diamond-Blackfan anemia.
- 2011
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Ingår i: Blood. - : American Society of Hematology. - 1528-0020 .- 0006-4971. ; 118, s. 6087-6096
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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. Among these genes, ribosomal protein S19 (RPS19) is mutated most frequently. Generation of animal models for diseases like DBA is challenging since the phenotype is highly dependent on the level of RPS19 downregulation. We report the generation of mouse models for RPS19-deficient DBA using transgenic RNA interference that allows an inducible and graded downregulation of Rps19. Rps19-deficient mice develop a macrocytic anemia together with leukocytopenia and variable platelet count that with time leads to the exhaustion of hematopoietic stem cells and bone marrow failure. Both RPS19 gene transfer and the loss of p53 rescue the DBA phenotype implying the potential of the models for testing novel therapies. This study demonstrates the feasibility of transgenic RNA interference to generate mouse models for human diseases caused by haploinsufficient expression of a gene.
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| 9. |
- Jaako, Pekka
(författare)
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Modeling Diamond-Blackfan Anemia in the Mouse: Disease Pathogenesis and Evaluation of Novel Therapies
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Diamond-Blackfan anemia (DBA) is a congenital erythroid hypoplasia that presents early in infancy. The main hematopoietic symptoms include macrocytic anemia with reticulocytopenia and selective absence of erythroid precursors in a normocellular bone marrow. In addition to the hematopoietic symptoms, DBA is characterized by the presence of physical abnormalities and cancer predisposition. Mutations in genes encoding ribosomal proteins have been identified in approximately 60-70% of DBA patients. Among these genes, ribosomal protein S19 (RPS19) is the most common disease gene (25% of the cases). All reported patients are heterozygous for the mutations and in most cases the mutations are predicted to result in haploinsufficiency of the respective ribosomal protein. Knowledge about DBA pathophysiology has been limited due to lack of appropriate animal models. The aim of this thesis was to generate mouse models for RPS19-deficient DBA and to use these models to study DBA pathophysiology and to evaluate novel therapies. In article I we generated and characterized novel mouse models for RPS19-deficient DBA. These models contain a doxycycline-regulatable Rps19-targeting shRNA that allows an inducible and graded downregulation of Rps19. We demonstrate that Rps19-deficient mice recapitulate many of the phenotypic and molecular features seen in patients, and are therefore well suited for the evaluation of novel therapies. In article II we used these mouse models to assess the therapeutic potential of the amino acid L-leucine in the treatment of DBA. We show that L-leucine treatment improves the anemia and alleviates the stress hematopoiesis in Rps19-deficient mice. In article III we evaluated the therapeutic efficacy of gene therapy using our mouse models for RPS19-deficient DBA. Using lentiviral vectors we demonstrate that enforced expression of RPS19 cures the lethal bone marrow failure in recipient mice transplanted with Rps19-deficient bone marrow cells. Taking together the generated mouse models provide novel tools to study DBA pathophysiology and to evaluate novel therapies. Our studies strengthen the rationale for clinical trials of L-leucine and provide a proof of principle for the development of clinical gene therapy in the treatment of RPS19-deficient DBA.
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| 10. |
- Singbrant, Sofie, et al.
(författare)
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Canonical BMP signaling is dispensable for hematopoietic stem cell function in both adult and fetal liver hematopoiesis, but essential to preserve colon architecture.
- 2010
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Ingår i: Blood. - : American Society of Hematology. - 1528-0020 .- 0006-4971. ; 115, s. 4689-4698
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Tidskriftsartikel (refereegranskat)abstract
- Numerous publications have described the importance of Bone Morphogenetic Protein (BMP) signaling in the specification of hematopoietic tissue in developing embryos. Here we investigate the full role of canonical BMP signaling in both adult and fetal liver hematopoiesis using conditional knockout strategies, since conventional disruption of components of the BMP signaling pathway result in early death of the embryo. By targeting both Smad1 and Smad5, we have generated a double knockout mouse with complete disruption of canonical BMP signaling. Interestingly, concurrent deletion of Smad1 and Smad5 results in death due to extra-hematopoietic pathological changes in the colon. However, Smad1/5 deficient bone marrow (BM) cells can compete normally with wild-type cells and display unaffected self-renewal and differentiation capacity when transplanted into lethally irradiated recipients. Moreover, although BMP receptor expression is increased in fetal liver, fetal liver cells deficient in both Smad1 and Smad5 remain competent to long-term reconstitute lethally irradiated recipients in a multi-lineage manner. In conclusion, canonical BMP signaling is not required to maintain either adult or fetal liver hematopoiesis, despite its crucial role in the initial patterning of hematopoiesis in early embryonic development.
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