Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04141 (granulocyte-macrophage colony-stimulating factor)
 6,790 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A new and quantitative liquid culture system has been developed to measure the production of megakaryocytes from megakaryocyte progenitor cells (colony-forming units-megakaryocyte [CFU-MK]). The system uses as a target population a glycoprotein (Gp) IIb/IIIa+ subpopulation of rat bone marrow cells previously demonstrated to be highly enriched for CFU-MK. GpIIb/IIIa+ cells were cultured at 5 x 10(4) cells/mL (10(4) cells/well) with test samples in 96-well tissue culture plates for 4 days at 37 degrees C. During the final 3 hours of incubation, the cells were pulsed with [14C]5-hydroxytryptamine creatinine sulfate (14C-serotonin). After incubation, the plates were washed and the cell pellets were lysed with Triton-X 100. The cell lysate was infiltrated into a commercially available solid scintillator and dried, and radioactivity was measured. In this assay system, rat interleukin-3 (IL-3) was found to be the most potent among known cytokines tested. Murine granulocyte-macrophage colony-stimulating factor (GM-CSF), human erythropoietin (Epo), human IL-6, and murine stem cell factor (SCF) each alone stimulated megakaryocyte growth but were much less active than rat IL-3. Plasma of rats rendered thrombocytopenic by injection of monoclonal antirat platelet GpIIb/IIIa antibody exhibited significant activity, and the active protein fractions partially purified from the plasma showed much higher activity, but normal rat plasma had no effect. This liquid culture system allows the measurement of a large number of test samples--including a wide variety of cytokines and unknown growth factors, alone or in combinations--and provides a simple method for evaluating the early proliferative events involving CFU-MK in the megakaryocyte differentiation pathway.
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PMID:A simple and quantitative liquid culture system to measure megakaryocyte growth using highly purified CFU-MK. 755 34

The local cytokine environment and presence of stimulatory signals determine whether monocytes acquire dendritic cell (DC) or macrophage characteristics and functions. Because enhanced platelet activation is reported in patients with many allergic disorders, such as atopic dermatitis, platelet-derived factors may influence monocytic differentiation into DC. In this study we examined the effect of serotonin, a prototypic mediator of allergic inflammation released mainly by activated platelets at the inflammatory site, on the granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin (IL)-4-driven differentiation of monocytes into monocyte-derived DC. Monocytes from healthy adult donors were cultured with GM-CSF and IL-4 in the presence or absence of serotonin, and the phenotypes and function of these cells were analysed. In the presence of serotonin, monocytes differentiated into DC with reduced expression of co-stimulatory molecules and CD1a, whereas expression of CD14 was increased. These serotonin-treated DC exhibited significantly reduced stimulatory activity toward allogeneic T cells. However, these cells showed enhanced cytokine-producing capacity, including IL-10 but not IL-12. There was no significant difference between both types of DC in phagocytic activity. Experiments using agonists and antagonists indicated that serotonin 5-hydroxytryptamine (5-HT) induced the alteration of their phenotype and reduction in antigen-presenting capacity were mediated via 5-HTR(1/7). It is therefore suggested that serotonin-driven DC may have a regulatory function in the inflammatory process.
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PMID:Effect of serotonin on the differentiation of human monocytes into dendritic cells. 1703 89

Avidin conjugates have several important applications in biotechnology and medicine. In this work, we investigated the possibility to produce site-specific derivatives of avidin using microbial transglutaminase (TGase). TGase allows the modification of proteins at the level of Gln or Lys residues using as substrate an alkyl-amine or a Gln-mimicking moiety, respectively. The reaction is site-specific, since Gln and Lys derivatization occurs preferentially at residues embedded in flexible regions of protein substrates. An analysis of the X-ray structure of avidin allowed us to predict Gln126 and Lys127 as potential sites of TGase's attack, because these residues are located in the flexible/unfolded C-terminal region of the protein. Surprisingly, incubation of avidin with TGase in the presence of alkylamine containing substrates (dansylcadaverine, 5-hydroxytryptamine) revealed a very low level of derivatization of the Gln126 residue. Analysis of the TGase reaction on synthetic peptide analogues of the C-terminal portion of avidin indicated that the lack of reactivity of Gln126 was likely due to the fact that this residue is proximal to negatively charged carboxylate groups, thus hampering the interaction of the substrate at the negatively charged active site of TGase. On the other hand, incubation of avidin with TGase in the presence of carbobenzoxy-l-glutaminyl-glycine in order to derivatize Lys residue(s) resulted in a clean and high yield production of an avidin derivative, retaining the biotin binding properties and the quaternary structure of the native protein. Proteolytic digestion of the modified protein, followed by mass spectrometry, allowed us to identify Lys127 as the major site of reaction, together with a minor modification of Lys58. By using TGase, avidin was also conjugated via a Lys-Gln isopeptide bond to a protein containing a single reactive Gln residue, namely, Gln126 of granulocyte-macrophage colony-stimulating factor. TGase can thus be exploited for the site-specific derivatization of avidin with small molecules or proteins.
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PMID:Site-specific derivatization of avidin using microbial transglutaminase. 2451 23