| 1. |
- NozadCharoudeh, Hojjatollah, et al.
(författare)
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Identification of a NK/T cell restricted progenitor in adult bone marrow contributing to bone marrow and thymic-dependent NK cells.
- 2010
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Ingår i: Blood. - : American Society of Hematology. - 1528-0020 .- 0006-4971. ; 116:2, s. 183-192
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Tidskriftsartikel (refereegranskat)abstract
- Although bone marrow (BM) is the main site of natural killer (NK)-cell development in adult mice, recent studies have identified a distinct thymic-dependent NK pathway, implicating a possible close link between NK- and T-cell development in adult hematopoiesis. To investigate whether a potential NK-/T-lineage restriction of multipotent progenitors might take place already in the BM, we tested the full lineage potentials of NK-cell progenitors in adult BM. Notably, although Lin(-)CD122(+)NK1.1(-)DX5(-) NK-cell progenitors failed to commit to the B and myeloid lineages, they sustained a combined NK- and T-cell potential in vivo and in vitro at the single-cell level. Whereas T-cell development from NK/T progenitors is Notch-dependent, their contribution to thymic and BM NK cells remains Notch-independent. These findings demonstrate the existence of bipotent NK-/T-cell progenitors in adult BM. (Blood. 2010; 116(2): 183-192)
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| 2. |
- Sitnicka Quinn, Ewa, et al.
(författare)
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Complementary Signaling through flt3 and Interleukin-7 Receptor {alpha} Is Indispensable for Fetal and Adult B Cell Genesis.
- 2003
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Ingår i: Journal of Experimental Medicine. - : Rockefeller University Press. - 1540-9538 .- 0022-1007. ; 198:10, s. 1495-1506
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Tidskriftsartikel (refereegranskat)abstract
- Extensive studies of mice deficient in one or several cytokine receptors have failed to support an indispensable role of cytokines in development of multiple blood cell lineages. Whereas B1 B cells and Igs are sustained at normal levels throughout life of mice deficient in IL-7, IL-7R{alpha}, common cytokine receptor gamma chain, or flt3 ligand (FL), we report here that adult mice double deficient in IL-7R{alpha} and FL completely lack visible LNs, conventional IgM+ B cells, IgA+ plasma cells, and B1 cells, and consequently produce no Igs. All stages of committed B cell progenitors are undetectable in FL-/- x IL-7R{alpha}-/- BM that also lacks expression of the B cell commitment factor Pax5 and its direct target genes. Furthermore, in contrast to IL-7R{alpha}-/- mice, FL-/- x IL-7R{alpha}-/- mice also lack mature B cells and detectable committed B cell progenitors during fetal development. Thus, signaling through the cytokine tyrosine kinase receptor flt3 and IL-7R{alpha} are indispensable for fetal and adult B cell development.
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| 3. |
- Sitnicka Quinn, Ewa, et al.
(författare)
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Critical role of FLT3 ligand in IL-7 receptor-independent T lymphopoiesis and regulation of lymphoid-primed multipotent progenitors
- 2007
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Ingår i: Blood. - Washington, DC : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 110:8, s. 2955-2964
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Tidskriftsartikel (refereegranskat)abstract
- The molecular pathways regulating lymphoid priming, fate, and development of multipotent bone marrow (BM) stem/progenitor cells that continuously replace thymic progenitors remain largely unknown. Herein, we show that fms-like tyrosine kinase 3 (Flt3) ligand (Fl)-deficient mice have distinct reductions in the earliest thymic progenitors in fetal, postnatal, and adult thymus. A critical role of FL in thymopoiesis was particularly evident in the absence of interleukin-7 receptor alpha (IL-7Ralpha) signaling. Fl-/-Il-7r-/- mice have extensive reductions in fetal and postnatal thymic progenitors that result in a loss of active thymopoiesis in adult mice, demonstrating an indispensable role of FL in IL-7Ralpha-independent fetal and adult T lymphopoiesis. Moreover, we establish a unique and critical role of FL, distinct from that of IL-7Ralpha, in regulation of the earliest lineage-negative (Lin(-)) Lin(-)SCA1+KIT+ (LSK) FLT3(hi) lymphoid-primed multipotent progenitors in BM, demonstrating a key role of FLT3 signaling in regulating the very earliest stages of lymphoid progenitors.
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| 4. |
- Svensson Frej, Marcus, et al.
(författare)
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Involvement of CCR9 at multiple stages of adult T lymphopoiesis.
- 2008
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Ingår i: Journal of Leukocyte Biology. - : Oxford University Press (OUP). - 1938-3673 .- 0741-5400. ; 83:1, s. 156-164
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Tidskriftsartikel (refereegranskat)abstract
- The chemokine CCL25 is constitutively expressed in the thymus, and its receptor CCR9 is expressed on subsets of developing thymocytes. Nevertheless, the function of CCL25/CCR9 in adult thymopoiesis remains unclear. Here, we demonstrate that purified CCR9–/– hematopoietic stem cells are deficient in their ability to generate all major thymocyte subsets including double-negative 1 (DN1) cells in competitive transfers. CCR9–/– bone marrow contained normal numbers of lineage– Sca-1+c-kit+, common lymphoid progenitors, and lymphoid-primed multipotent progenitors (LMPP), and CCR9–/– LMPP showed similar T cell potential as their wild-type (WT) counterparts when cultured on OP9–{delta}-like 1 stromal cells. In contrast, early thymic progenitor and DN2 thymocyte numbers were reduced in the thymus of adult CCR9–/– mice. In fetal thymic organ cultures (FTOC), CCR9–/– DN1 cells were as efficient as WT DN1 cells in generating double-positive (DP) thymocytes; however, under competitive FTOC, CCR9–/– DP cell numbers were reduced significantly. Similarly, following intrathymic injection into sublethally irradiated recipients, CCR9–/– DN cells were out-competed by WT DN cells in generating DP thymocytes. Finally, in competitive reaggregation thymic organ cultures, CCR9–/– preselection DP thymocytes were disadvantaged significantly in their ability to generate CD4 single-positive (SP) thymocytes, a finding that correlated with a reduced ability to form TCR-MHC-dependent conjugates with thymic epithelial cells. Together, these results highlight a role for CCR9 at several stages of adult thymopoiesis: in hematopoietic progenitor seeding of the thymus, in the DN-DP thymocyte transition, and in the generation of CD4 SP thymocytes.
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