Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0153470 (Spleen)
 4,015 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

During embryonic development, the components of the avian immune system undergo ontogeny in several distinct organs, including the bone marrow, spleen, thymus, and bursa of Fabricius. This process is regulated and controlled by the complex interactions of various cytokines and colony-stimulating factors (CSF). The objective was to examine the action of two different sources of hematopoietic growth factors, spleen-conditioned media (SCM) and chick embryo extract (CEE), on the proliferation of hematopoietic cells from various organs and on the differentiation of progenitor cells in semi-solid culture. Spleen and bone marrow cells obtained at Day 16 of incubation responded in a dose-dependent manner to the addition of SCM and CEE alone or in combination. No proliferative effect of SCM was observed on cells obtained from embryonic thymus or bursa. Clonal analysis of bone marrow and spleen cells suggested that CEE may contain the avian equivalents of stem cell factor, interleukin-3, granulocyte-macrophage CSF, granulocyte-CSF, and macrophage-CSF. Clonal analysis of SCM cultures suggested that in addition to myelomonocytic growth factor, which affects primarily macrophage-granulocyte lineages, a thrombocyte-CSF-like activity was also apparent. The SCM alone tended to act upon committed late progenitors. The combination of CEE and SCM amplified the size and the total number of colonies obtained and appeared to act synergistically upon progenitors with a high level of proliferative potential. This response on young progenitors was confirmed when cells were cultured in CEE and SCM prior to clonal analysis. These results document the presence of thrombocyte CSF in SCM and the effect of both CEE and SCM on the proliferative differentiation of avian embryonic hematopoietic progenitors.
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PMID:Synergistic action of two sources of avian growth factors on proliferative differentiation of chick embryonic hematopoietic cells. 747 87

The mobilization of hematopoietic stem cells (HSCs) into the peripheral blood of mice was induced by recombinant human granulocyte colony-stimulating factor (rhG-CSF) (250 microgram/kg/d) alone or combined with recombinant rat stem cell factor (rrSCF) (34 microgram/kg/d), injected subcutaneously (s.c.) once a day for 10 and 17 days. After administering G-CSF plus SCF or G-CSF alone for 10 days, the level of day-11 spleen colony-forming units (CFU-S-11) in the peripheral blood increased 169- and 93-fold, respectively. The effect was lower--30- and 17-fold--after 17 days of treatment. A 1.5- to three-fold decrease in CFU-S-11 content in the bone marrow of treated mice was observed. In normal mice, the content of long-term culture initiating cells (LTC-IC) in blood was below the threshold level. Cytokine treatment mobilized LTC-IC in the circulation. Following a 10- and 17-day course of G-CSF plus SCF, the proliferation of CFU-S-11 in the peripheral blood but not in the bone marrow increased from <10% in the controls to 44 and 72%, respectively, as measured by hydroxyurea (HU) suicide. Spleen-repopulating ability (SRA) of CFU-S (daughter CFU-S-8 content in an 11-day-old spleen colony) increased two-fold in the peripheral blood after a 10-day course and seven-fold after a 17-day course of combined cytokines. One month after the final cytokine injection, all hematopoietic indexes (including the number of different precursors, their proliferative rate, and their SRA) were near normal. The results suggest that the age structure of the mobilized progenitor population depends on both the cytokines used and the duration of the treatment: more immature CFU-S with higher proliferative activity and an increased SRA were mobilized preferentially after a 17-day course of combined cytokines.
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PMID:Effect of cytokine treatment (granulocyte colony-stimulating factor and stem cell factor) on hematopoiesis and the circulating pool of hematopoietic stem cells in mice. 864 32

We have recently isolated the erythroleukemic cell line, HB60-5, that proliferates in the presence of erythropoietin (Epo) and stem cell factor (SCF), but undergoes terminal differentiation in the presence of Epo alone. Ectopic expression of the ets related transcription factor Fli-1 in these cells resulted in the establishment of the Epo-dependent cell line HB60-ED that proliferates in the presence of Epo. In this study, we utilized these two cell lines to examine the signal transduction pathways that are activated in response to Epo and SCF stimulation. We demonstrate that Epo, but not SCF, phosphorylates STAT-5 in both HB60-5 and HB60-ED cells. Interestingly, SCF activates the Shc/ras pathway in HB60-5 cells while Epo does not. However, both Epo and SCF are capable of activating the Shc/ras pathway in HB60ED cells. Furthermore, enforced expression of gp55 in HB60-5 cells by means of infection with the Spleen Focus Forming virus-P (SFFV-P), confers Epo independent growth, which is associated with the up-regulation of Fli-1. Activation of the Shc/ras pathway is readily detected in gp55 expressing cells in response to both Epo and SCF, and is associated with a block in STAT-5B tyrosine phosphorylation. These results suggest that STAT-5 activation, in the absence of Shc/ras activation, plays a role in erythroid differentiation. Moreover, Fli-1 is capable of switching Epo-induced differentiation to Epo-induced proliferation, suggesting that this ets factor regulated genes whose products modulate the Epo-Epo-R signal transduction pathway.
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PMID:Epo regulates erythroid proliferation and differentiation through distinct signaling pathways: implication for erythropoiesis and Friend virus-induced erythroleukemia. 1082 80