| 1. |
- Kahn, J, et al.
(författare)
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Overexpression of CXCR4 on human CD34(+) progenitors increases their proliferation, migration, and NOD/SCID repopulation
- 2004
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Ingår i: Blood. - : American Society of Hematology. - 1528-0020 .- 0006-4971. ; 103:8, s. 2942-2949
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Tidskriftsartikel (refereegranskat)abstract
- A major limitation to clinical stem cell-mediated gene therapy protocols is the low levels of engraftment by transduced progenitors. We report that CXCR4 overexpression on human CD34(+) progenitors using a lentiviral gene transfer technique helped navigate these cells to the murine bone marrow and spleen in response to stromal-derived factor 1 (SDF-1) signaling. Cells overexpressing CXCR4 exhibited significant increases in SDF-1-mediated chemotaxis and actin polymerization compared with control cells. A major advantage of CXCR4 overexpression was demonstrated by the ability of transduced CD34(+) cells to respond to lower, physiologic levels of SDF-1 when compared to control cells, leading to improved SDIF-1-induced migration and proliferation/survival, and finally resulting in significantly higher levels of in vivo repopulation of nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice including primitive CD34(+)/CD38(-/low) cells. Importantly, no cellular transformation was observed following transduction with the CXCR4 vector. Unexpectedly, we documented lack of receptor internalization in response to high levels of SDF-1, which can also contribute to increased migration and proliferation by the transduced CD34(+) cells. Our results suggest CXCR4 overexpression for improved definitive human stem cell motility, retention, and multilineage repopulation, which could be beneficial for in vivo navigation and expansion of hematopoietic progenitors.
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| 2. |
- Larsson, Jonas, et al.
(författare)
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Abnormal angiogenesis but intact hematopoietic potential in TGF-beta type I receptor-deficient mice
- 2001
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Ingår i: EMBO Journal. - : Wiley. - 1460-2075. ; 20:7, s. 1663-1673
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Tidskriftsartikel (refereegranskat)abstract
- Deletion of the transforming growth factor beta1 (TGF-beta1) gene in mice has previously suggested that it regulates both hematopoiesis and angiogenesis. To define the function of TGF-beta more precisely, we inactivated the TGF-beta type I receptor (T beta RI) gene by gene targeting. Mice lacking T beta RI die at midgestation, exhibiting severe defects in vascular development of the yolk sac and placenta, and an absence of circulating red blood cells. However, despite obvious anemia in the T beta RI-/- yolk sacs, clonogenic assays on yolk sac-derived hematopoietic precursors in vitro revealed that T beta RI-/- mice exhibit normal hematopoietic potential compared with wild-type and heterozygous siblings, Endothelial cells derived from T beta RI-deficient embryos show enhanced cell proliferation, improper migratory behavior and impaired fibronectin production in vitro, defects that are associated with the vascular defects seen in vivo. We thus demonstrate here that, while T beta RI is crucial for the function of TGF-beta during vascular development and can not be compensated for by the activin receptor-like kinase-1 (ALK-1), functional hematopoiesis and development of hematopoietic progenitors is not dependent on TGF-beta signaling via T beta RI.
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| 3. |
- Levéen, Per, et al.
(författare)
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Induced disruption of the transforming growth factor beta type II receptor gene in mice causes a lethal inflammatory disorder that is transplantable.
- 2002
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Ingår i: Blood. - 1528-0020. ; 100:2, s. 560-568
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Tidskriftsartikel (refereegranskat)abstract
- Recent studies in mouse models deficient in transforming growth factor beta (TGF-beta) signaling have documented TGF-beta as one of the major regulators of immune function. TGF-beta1-null animals demonstrated massive autoimmune inflammation affecting multiple organs, but attempts to transfer the phenotype to normal animals by bone marrow transplantation only resulted in minor inflammatory lesions. We wanted to ask whether a lethal inflammatory phenotype would develop following transplantation of bone marrow deficient for the TGF-beta type II receptor (TbetaRII) gene to normal recipient animals. The TbetaRII-null mutation would generate a cell autonomous phenotype that cannot be reverted by the influence of endocrine or paracrine TGF-beta derived from the recipient animal. We have generated conditional knockout mice in which the TbetaRII gene is disrupted upon induction with interferon-alphabeta or polyI:polyC. We show that induction of TbetaRII gene disruption in these mice by polyI:polyC results in a lethal inflammatory disease. Importantly, bone marrow from conditional knockout mice transferred to normal recipent mice caused a similar lethal inflammation, regardless of whether induction of TGF-beta receptor deficiency occurred in donor animals before, or in recipient animals after transplantation. These results show that TGF-beta signaling deficiency within cells of hematopoietic origin is sufficient to cause a lethal inflammatory disorder in mice. This animal model provides an important tool to further clarify the pathogenic mechanisms in animals deficient for TGF-beta signaling and the importance of TGF-beta to regulate immune functions. (Blood. 2002;100:560-568)
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