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)

Highly purified progenitors (including erythroid [BFU-E], granulo-monocytic [CFU-GM], multipotent [CFU-GEMM] progenitors, as well as multipotent progenitors with self-renewal capacity [CFU-B]) express high-affinity growth factor receptors (GFRs), with prevalent interleukin-3 receptors (IL-3Rs) (2,700/cell), a > or = 10-fold lower number of IL-6Rs (145/cell) and granulocyte-macrophage colony-stimulating factor receptors (GM-CSFRs) (300/cell), and a barely detectable level of erythropoietin (Ep) receptors (75/cell). Hematopoietic growth factor (HGF) dosages inducing peak clonogenetic effects are associated with partial/subtotal occupancy of the homologous HGF receptor (HGFR). Cross-reactivity between GFRs and heterologous GFs (including IL-6, IL-3, GM-CSF, Ep, and the kit ligand [KL]) was explored by competition experiments on purified progenitors with radiolabeled and excess cold HGFs at +4 degrees C. No cross-reaction was observed between IL-6R, IL-3R, EpR, and the heterologous GFs, whereas the GM-CSFR showed cross-reactivity with IL-3 and, to a lesser extent, KL. Modulation of GFRs was examined after 18 or 40 hours of incubation with GF(s) at 37 degrees C, followed by ligand-binding assay at 20 degrees C. IL-6, IL-3, GM-CSF, and Ep induce a marked down-modulation of their own receptors. Interestingly, each GF induces the transactivation of the R(s) for the "distal" GF(s): (1) IL-6 induces transactivation of IL-3R, but not of GM-CSFR/EpR; (2) IL-3 causes a rapid upmodulation of GM-CSFR/EpR ("pure" progenitors treated with IL-3 show upmodulation of GM-CSFR alpha-chain mRNA by reverse transcriptase-polymerase chain reaction); whereas (3) GM-CSF induces the transactivation of the EpR. This chain upmodulation of HGFRs may underlie the synergistic interactions between the HGFs in clonogenetic culture. It is emphasized that KL does not induce upmodulation of the other GFRs. Finally, Ep, GM-CSF, and IL-3 do not modulate the expression of the "proximal" HGFRs (ie, GM-CSFR/IL-3R/IL-6R, IL-3R/IL-6R, and IL-6R, respectively). These results allow insight into the cellular basis of hematopoiesis, ie, the complex and coordinate interactions between HGFs and their receptors. They are compatible with a model of cascade transactivation via upmodulation of GFRs in the initial key steps of hematopoietic differentiation, whereby the action of each GF enhances the effect of the distal GF(s) by a multistep chain-potentiation mechanism.
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PMID:Cascade transactivation of growth factor receptors in early human hematopoiesis. 845 93

Bone marrow (BM) stromal cells are required for normal hematopoiesis. A number of soluble factors secreted by these cells that mediate hematopoiesis have been characterized. However, the mechanism of hematopoiesis cannot be explained solely by these known factors, and the existence of other, still unknown stromal factors has been postulated. We showed that hepatocyte growth factor (HGF) is one such cytokine produced by human BM stromal cells. BM stromal cells were shown to constitutively produce HGF and also to express the c-MET/HGF receptor. The production of HGF was enhanced by addition of heparin and phorbol ester. Dexamethasone and tumor growth factor-beta (TGF-beta) inhibited the production of HGF. Interleukin-1 alpha (IL-1 alpha) tumor necrosis factor-alpha (TNF-alpha), and N6,2'-o-dibutyryl-adenosine-3':5'-cyclic monophosphate (dbc-AMP) showed no obvious influence on HGF production. Western blot analysis of HGF derived from BM stromal cells showed two bands at 85 and 28 kD corresponding to native and variant HGF, respectively. Addition of recombinant HGF significantly promoted the formation of burst-forming unit-erythroid (BFU-E) and colony-forming unit-granulocyte erythroid macrophage (CFU-GEM) by BM mononuclear cells in the presence of erythropoietin and granulocyte-macrophage colony-stimulating factor (GM-CSF), but the formation of CFU-GM was not modified. However, HGF had no effects on colony formation by purified CD34+ cells. Within BM mononuclear cells, c-MET was expressed on a proportion of cells (CD34-, CD33+, CD13+, CD14+, and CD15+), but was not found on CD34+ cells. We conclude that HGF is constitutively produced by BM stromal cells and that it enhances hematopoiesis. In addition, expression of c-MET on the stromal cells suggests the presence of an autocrine mechanism, operating through HGF, among stromal cells.
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PMID:Hepatocyte growth factor is constitutively produced by human bone marrow stromal cells and indirectly promotes hematopoiesis. 905 37

Hematopoietic growth factors (HGFs) act on the hematopoietic cells via binding to specific cell surface receptors. Many HGF receptors have certain common structural features and have therefore been grouped in the superfamily of hematopoietin or cytokine receptors, also referred to as the class I receptor superfamily [1, 2]. Activation of these receptors by their cognate growth factors is mediated through the formation of dimeric or oligomeric complexes of receptor structures. Some HGF receptors are composed of heteromeric complexes, comprising two or three different receptor chains. For instance, this is the case for receptors of interleukins 2, 3, and 5 and granulocyte-macrophage colony-stimulating factor [3]. Other receptor structures, for example, those of granulocyte colony-stimulating factor and erythropoietin, form homodimeric complexes upon growth factor binding [2, 4]. This brief overview begins with an introduction of the major principles of HGF receptor signaling: this is followed by a discussion of the consequences of HGF receptor signaling defects for the development of disorders of the hematopoietic system and the presentation of clinical examples of such diseases.
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PMID:Molecular understanding of hematopoietin/cytokine receptor signaling defects in hematopoietic disorders. 925 10

Increased numbers of tumor-infiltrating neutrophils are linked to poorer outcome in patients with adenocarcinoma of the bronchioloalveolar carcinoma (BAC) subtype. Hepatocyte growth factor (HGF) is a pleiotropic cytokine operating through activation of the proto-oncogene c-met and is a factor of poor prognosis in various cancers. Reports that neutrophils produce HGF led us to investigate their participation in the aerogenous spread of tumor cells and the prognosis of BAC, through the effect of HGF on c-met-expressing tumor cells. Immunoreactive HGF was detected in bronchoalveolar lavage fluid (BALF) supernatants from 34 of 36 patients, whereas it was undetectable in BALF from healthy controls. The HGF thus detected was locally produced, because HGF mRNA was expressed by the patients' fresh alveolar cells, and HGF protein was detected in 24-h culture supernatants. In immunocytochemical studies of BALF cytospin preparations and tumor specimens from the patients, neutrophils were always HGF-positive, whereas alveolar macrophages and tumor cells gave inconsistent results. Alveolar neutrophil-derived HGFs induced significant, concentration-dependent migration of BAC-derived tumor cells in vitro, and this effect was inhibited by anti-HGF neutralizing antibodies. Granulocyte-macrophage colony-stimulating factor and tumor necrosis factor alpha (present in the lung tumor microenvironment) provoked HGF release from neutrophil intracellular stocks, and the capacity of blood neutrophils from BAC patients to produce HGF was unaltered. Immunochemical studies of c-met expression in BALF cytospin preparations and tumor sections showed that most HGF receptor-bearing cells were tumor cells. High HGF levels in BALF supernatants were significantly associated with poorer outcome in patients with BAC and were an independent predictor of clinical outcome in multivariate analysis. Altogether, our results support the notion that BAC generates a local environment that attracts functionally normal neutrophils from peripheral blood and leads to neutrophil release of biologically active HGF on contact with HGF receptor-expressing tumor cells, thereby contributing to poorer patient outcome.
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PMID:Hepatocyte growth factor production by neutrophils infiltrating bronchioloalveolar subtype pulmonary adenocarcinoma: role in tumor progression and death. 1264 6