Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P05231 (interleukin-6)
 23,907 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have used a competitive repopulation assay in baboons to develop improved methods for hematopoietic stem cell transduction and have previously shown increased gene transfer into baboon marrow repopulating cells using a gibbon ape leukemia virus (GALV)-pseudotype retroviral vector (Kiem et al, Blood 90:4638, 1997). In this study using GALV-pseudotype vectors, we examined additional variables that have been reported to increase gene transfer into hematopoietic progenitor cells in culture for their ability to increase gene transfer into baboon hematopoietic repopulating cells. Baboon marrow was harvested after in vivo administration (priming) of stem cell factor (SCF) and granulocyte colony-stimulating factor (G-CSF). CD34-enriched marrow cells were divided into two equal fractions to directly compare transduction efficiencies under different gene transfer conditions. Transduction by either incubation with retroviral vectors on CH-296-coated flasks or by cocultivation on vector-producing cells was studied in five animals; in one animal, transduction on CH-296 was compared with transduction on bovine serum albumin (BSA)-coated flasks. The highest level of gene transfer was obtained after 24 hours of prestimulation followed by 48 hours of incubation on CH-296 in vector-containing medium in the presence of multiple hematopoietic growth factors (interleukin-6, stem cell factor, FLT-3 ligand, and megakaryocyte growth and development factor). Using these conditions, up to 20% of peripheral blood and marrow cells contained vector sequences for more than 20 weeks, as determined by both polymerase chain reaction and Southern blot analysis. Gene transfer rates were higher for cells transduced on CH-296 as compared with BSA or cocultivation. In one animal, we have used a vector expressing a cell surface protein (human placental alkaline phosphatase) and have detected 10% and 5% of peripheral blood cells expressing the transduced gene 2 and 4 weeks after transplantation as measured by flow cytometry. In conclusion, the conditions described here have resulted in gene transfer rates that will allow detection of transduced cells by flow cytometry to facilitate the evaluation of gene expression. The levels of gene transfer obtained with these conditions suggest the potential for therapeutic efficacy in diseases affecting the hematopoietic system.
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PMID:Improved gene transfer into baboon marrow repopulating cells using recombinant human fibronectin fragment CH-296 in combination with interleukin-6, stem cell factor, FLT-3 ligand, and megakaryocyte growth and development factor. 973 Oct 44

Thrombopoietin (Mpl ligand), interleukin-6 (IL-6), and interleukin-11 (IL-11) differ in their effects on megakaryocyte maturation and development. In the present study, the impact of these thrombocytopoietic cytokines on biochemical and structural granule and membrane components was examined. Western blotting was performed on equivalent amounts of isolated megakaryocyte or platelet protein and the relative intensities of the enhanced chemiluminescent-visualized bands were quantitated by densitometry. Megakaryocyte growth and development factor (MGDF), a recombinant thrombopoietin-related molecule, significantly increased megakaryocyte fibronectin (72%), thrombospondin (55%), von Willebrand factor (28%) and p-selectin (CD62p) (37%) when compared to equivalent amounts of protein from saline-treated controls (p<0.01). Megakaryocyte fibrinogen was not increased. Ultrastructurally, there was a marked increase in ribosomes and rough endoplasmic reticulum even in mature-appearing megakaryocytes. Platelets from MGDF-treated mice showed small increases in fibronectin (8%), and CD62p (18%), but did not show increases in other measured alpha-granule proteins. Neither IL-6 nor IL-11 increased megakaryocyte or platelet alpha-granule proteins over levels observed in saline controls. IL-11 treated megakaryocytes, while also exhibiting an increase in ribosomes, were characterized by prominent cytoplasmic fragmentation. The study demonstrates the impact of Mpl ligand in increasing synthesized megakaryocyte alpha-granule proteins and of IL-11 in promoting megakaryocyte fragmentation.
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PMID:The effects of Mpl-ligand, interleukin-6 and interleukin-11 on megakaryocyte and platelet alpha-granule proteins. 986 69

Thrombocytopenia is a major cause of morbidity following intensive chemotherapy for acute leukemia. Over recent years, there has been an increasing use of platelet transfusions which, although generally efficacious to prevent severe hemorrhage, have associated risks of transmitting blood-borne disease and of alloimmunization. Therefore, there is a clinical requirement for a drug that will reliably alleviate the thrombocytopenia associated with leukemia therapy. The c-mpl ligand thrombopoietin is the most interesting factor for the treatment of thrombocytopenia because of its lineage specificity. Phase I and II studies confirm its biological efficacy to induce rise in platelet count in patients with solid tumors and acute leukemia. Several other pleiotropic hematopoietic growth factors are also currently in clinical trials. These include interleukin-6, interleukin-3, interleukin-11, PIXY321 and stem cell factor. The effects of these cytokines appear to be modest at most and, with the exception of interleukin-11, their side effects are likely to limit their clinical application. Combinations of factors may prove more efficacious approaches to enhance platelet recovery.
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PMID:Thrombopoietic factors potentially useful in the treatment of acute leukemia. 992 79

Understanding the repopulating characteristics of human hematopoietic stem/progenitor cells is crucial for predicting their performance after transplant into patients receiving high-dose radiochemotherapy. We have previously reported that CD34(+) cord blood (CB) cells can be expanded in vitro for several months in serum containing culture conditions. The use of combinations of recombinant early acting growth factors and the absence of stroma was essential in determining this phenomenon. However, the effect of these manipulations on in vivo repopulating hematopoietic cells is not known. Recently, a new approach has been developed to establish an in vivo model for human primitive hematopoietic precursors by transplanting human hematopoietic cells into sublethally irradiated nonobese diabetic severe combined immunodeficient (NOD/SCID) mice. We have examined here the expansion of cells, CD34(+) and CD34(+)38(-) subpopulations, colony-forming cells (CFC), long-term culture initiating cells (LTC-IC) and the maintenance or the expansion of SCID-repopulating cells (SRC) during stroma-free suspension cultures of human CD34(+) CB cells for up to 12 weeks. Groups of sublethally irradiated NOD/SCID mice were injected with either 35,000, 20,000, and 10,000 unmanipulated CD34(+) CB cells, which were cryopreserved at the start of cultures, or the cryopreserved cells expanded from 35,000, 20,000, or 10,000 CD34(+) cells for 4, 8, and 12 weeks in the presence of a combination of early acting recombinant growth factors (flt 3/flk2 ligand [FL] + megakaryocyte growth and development factor [MGDF] +/- stem cell factor [SCF] +/- interleukin-6 [IL-6]). Mice that had been injected with >/=20,000 fresh or cryopreserved uncultured CD34(+) cells did not show any sign or showed little engraftment in a limited number of animals. Conversely, cells that had been generated by the same number of initial CD34(+) CB cells in 4 to 10 weeks of expansion cultures engrafted the vast majority of NOD/SCID mice. The level of engraftment, well above that usually observed when the same numbers of uncultured cells were injected in the same recipients (even in the presence of irradiated CD34(-) cells) suggested that primitive hematopoietic cells were maintained for up to 10 weeks of cultures. In addition, dilution experiments suggest that SRC are expanded more than 70-fold after 9 to 10 weeks of expansion. These results support and extend our previous findings that CD34(+) CB stem cells (identified as LTC-IC) could indeed be grown and expanded in vitro for an extremely long period of time. Such information may be essential to design efficient stem cell expansion procedures for clinical use.
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PMID:Engraftment in nonobese diabetic severe combined immunodeficient mice of human CD34(+) cord blood cells after ex vivo expansion: evidence for the amplification and self-renewal of repopulating stem cells. 1033 80

The thrombocytopenia and absent radii (TAR) syndrome is a rare disease associating bilateral radial agenesis and congenital thrombocytopenia. Here, we investigated in vitro megakaryocyte (MK) differentiation and expression of c-mpl in 6 patients. Using blood or marrow CD34(+) cells, the colony-forming unit (CFU)-MK number was markedly reduced. CD34(+) cells were also cultured in liquid medium in the presence of a combination of 3 cytokines (stem cell factor, interleukin-3, and interleukin-6) or megakaryocyte growth and development factor (PEG-rHuMGDF) with or without SCF. In the presence of PEG-rHuMGDF, the majority of mature megakaryocytes (CD41 high, CD42 high) underwent apoptosis. This phenomenon was also observed in cultures stimulated by three cytokines. However, this last combination of cytokines allowed a more complete terminal MK differentiation. Surprisingly, a homogeneous population of CD34(-)CD41(+)CD42(-) cells accumulated during the cultures. This population was unable to differentiate along the myeloid pathways. This result suggests that a fraction of MK cells is unable to differentiate in the TAR syndrome. We subsequently investigated whether this could be related to an abnormality in c-mpl. No mutation or rearrangement in the c-mpl gene was found by Southern blots or by sequencing of the c-mpl coding region and its promoter in any of the patients. Using Western blot analysis, a decreased level of Mpl was found in patient platelets. A decreased level of c-mpl messenger RNA in TAR platelets was also detected with a lower c-mpl-P to c-mpl-K ratio in comparison to adult platelets. Altogether, these results demonstrate that the thrombocytopenia of the TAR syndrome is associated with a dysmegakaryocytopoiesis characterized by cells blocked at an early stage of differentiation. (Blood. 2000;95:1633-1641)
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PMID:Existence of a differentiation blockage at the stage of a megakaryocyte precursor in the thrombocytopenia and absent radii (TAR) syndrome. 1068 18

Congenital thrombocytopenia with absent radii (TAR syndrome) is characterized by defective thrombopoiesis and bleeding in early infancy. To determine the frequency and responsiveness to cytokines of megakaryocyte progenitors (CFU-Meg) in TAR syndrome, the authors studied marrow samples from 3 patients and 6 normal controls, using optimally standardized megakaryocyte growth media incorporating interleukin-3, interleukin-6, stem cell factor, and granulocyte-monocyte colony-stimulating factor, with and without pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF). CFU-Meg was identified with a specific staining system utilizing monoclonal antibodies to glycoprotein IIb/IIIa. Growth of small CFU-Meg colonies (3-20 cells/colony) was observed in all patients in cultures without PEG-rHuMGDF, with a mean frequency of 8 (range 5-12) per 2.25 x 10(5) mononuclear cells plated (control mean 23; range 2-70). Identical cultures of marrow cells from patients and controls with added PEG-rHuMGDF produced more colonies per dish (mean 17, range 8-23; control mean 30, range 6-62). Except for 1 case, however, patients' colonies in response to PEG-rHuMGDF remained smaller than those of controls. Two patients tested had higher plasma thrombopoietin levels than 6 normal subjects. The findings demonstrate proliferative and PEG-rHuMGDF-responsive megakaryocytic progenitors in TAR syndrome. The modest reduction in frequency of megakaryocyte progenitors and the suboptimal size of colonies in response to PEG-rHuMGDF are compatible with the reported defective signal transduction in the c-mpl pathway in TAR syndrome.
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PMID:Thrombocytopenia with absent radii: frequency of marrow megakaryocyte progenitors, proliferative characteristics, and megakaryocyte growth and development factor responsiveness. 1103 26

The aim of this study was to clarify the mechanisms that regulate hematopoietic cell expansion in vitro by identifying defined culture conditions. We report the results of experiments with CD34(+) cells from cord blood (CB, n = 13), bone marrow (BM, n = 4), and mobilized peripheral blood stem cells (PBSC, n = 5) using two combinations of cytokines: (A) granulocyte colony-stimulating factor (G-CSF), interleukin-3 (IL-3), interleukin-6 (IL-6), stem cell factor (SCF), erythropoietin (EPO), insulin-like growth factor-1 (IGF-1), basic fibroblast growth factor (FGF-b) and (B) combination A plus FLT3 ligand (FL) and megakaryocyte growth and development factor (PEG rhMGDF). Cultures of immunoselected CD34(+) cells were performed in serum-free liquid medium without serum substitutes. The area under the curve (AUC) obtained by plotting the logarithm of the total number of viable cells, CD34(+) cells, and CFC per well, toward the week of culture was used as an index of cell expansion. With CB, a significant difference was obtained between the two combinations of cytokines with regard to the total number of viable cells, GM-CFC, and CD34(+) cells. The difference between the two combinations of cytokines obtained with BM was significant with respect to the total number of viable cells and CD34(+) cells but not for the erythroid and myeloid progenitors. When CD34(+) cells from peripheral blood stem cells (PBSC) were cultured in presence of the two combinations of cytokines, the difference in terms of AUC was not statistically significant. Our data indicate additional effects in terms of proliferation and expansion of hematopoietic cells in serum-free conditions when FL and polyethylene glycol (PEG) rhMGDF are included in culture and suggest a differential activity of these cytokines on cells from different hematopoietic sources.
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PMID:Effect of addition of FLT-3 ligand and megakaryocyte growth and development factor on hemopoietic cells in serum-free conditions. 1534 30


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