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

We obtained a human myeloma cell line (XG4-CNTF) whose growth was completely dependent on addition of ciliary neurotrophic factor (CNTF). Half-maximal proliferation was induced by adding 20 pg/mL CNTF. Response to CNTF correlated with expression of membrane CNTF receptor alpha-chain (CNTFR alpha), as shown by PCR analysis and immunostaining with anti-CNTFR alpha antibodies. CNTF-induced proliferation was completely inhibited by antibodies to gp130 interleukin-6 (IL-6) transducer, unlike antibodies to IL-6 or IL-6 receptor (IL-6R). Growth of XG4-CNTF cells using the gp130 IL-6 transducer was also supported by other cytokines: IL-6, leukemia inhibitory factor (LIF), and oncostatin M (OM). This cell line should be very useful for studying the interactions of IL-6-related cytokines with their receptors.
 ...
PMID:A ciliary neurotrophic factor-sensitive human myeloma cell line. 876 94

Two of the most potent cytokines regulating anterior pituitary cell function are leukemia inhibitory factor and interleukin-6 (IL-6), which belong to the cytokine receptor family using the common gp130 signal transducer. We studied the actions of two other members of this family, IL-11 and ciliary neurotropic factor (CNTF), on folliculostellate (FS) cells (TtT/GF cell line) and lactosomatotropic cells (GH3 cell line). The messenger RNA (mRNA) for the alpha-chain specific for the IL-11 receptor (1.7 kb) and CNTF receptor (2 kb) are expressed on both cell types. In addition, we detected CNTF receptor mRNA in normal rat anterior pituitary cells. IL-11 (1.25-5 nM) dose dependently stimulated the proliferation of FS cells. CNTF, at doses from 0.4-2 nM, also significantly stimulated the growth of these cells. In addition, both cytokines significantly stimulated proliferation of lactosomatotropic GH3 cells, and CNTF stimulated hormone production (GH and PRL) at 24 h by these cells. At 16-72 h, IL-11 stimulates the secretion of the angiogenic factor vascular endothelial growth factor by FS cells. In addition, both GH3 and FS cells express CNTF mRNA. These data suggest that IL-11 and CNTF may act as growth and regulatory factors in anterior pituitary cells.
 ...
PMID:The gp130 cytokines interleukin-11 and ciliary neurotropic factor regulate through specific receptors the function and growth of lactosomatotropic and folliculostellate pituitary cell lines. 1080 85

Ciliary neurotrophic factor (CNTF) is expressed in glial cells within the central and peripheral nervous systems. CNTF stimulates gene expression, cell survival or differentiation in a variety of neuronal cell types such as sensory, sympathetic, ciliary and motor neurons. In addition, effects of CNTF on oligodendrocytes as well as denervated and intact skeletal muscle have been documented. CNTF itself lacks a classical signal peptide sequence of a secreted protein, but is thought to convey its cytoprotective effects after release from adult glial cells by some mechanism induced by injury. Interestingly, mice that are homozygous for an inactivated CNTF gene develop normally and initially thrive. Only later in adulthood do they exhibit a mild loss of motor neurons with resulting muscle weakness, leading to the suggestion that CNTF is not essential for neural development, but instead acts in response to injury or other stresses. The CNTF receptor complex is most closely related to, and shares subunits with the receptor complexes for interleukin-6 and leukemia inhibitory factor. The specificity conferring alpha subunit of the CNTF complex (CNTFR alpha), is extremely well conserved across species, and has a distribution localized predominantly to the nervous system and skeletal muscle. CNTFR alpha lacks a conventional transmembrane domain and is thought to be anchored to the cell membrane by a glycosyl-phosphatidylinositol linkage. Mice lacking CNTFR alpha die perinatally, perhaps indicating the existence of a second developmentally important CNTF-like ligand. Signal transduction by CNTF requires that it bind first to CNTFR alpha, permitting the recruitment of gp130 and LIFR beta, forming a tripartite receptor complex. CNTF-induced heterodimerization of the beta receptor subunits leads to tyrosine phosphorylation (through constitutively associated JAKs), and the activated receptor provides docking sites for SH2-containing signaling molecules, such as STAT proteins. Activated STATs dimerize and translocate to the nucleus to bind specific DNA sequences, resulting in enhanced transcription of responsive genes. The neuroprotective effects of CNTF have been demonstrated in a number of in vitro cell models as well as in vivo in mutant mouse strains which exhibit motor neuron degeneration. Intracerebral administration of CNTF and CNTF analogs has also been shown to protect striatal output neurons in rodent and primate models of Huntington's disease. Treatment of humans and animals with CNTF is also known to induce weight loss characterized by a preferential loss of body fat. When administered systemically, CNTF activates downstream signaling molecules such as STAT-3 in areas of the hypothalamus which regulate food intake. In addition to its neuronal actions, CNTF and analogs have been shown to act on non-neuronal cells such as glia, hepatocytes, skeletal muscle, embryonic stem cells and bone marrow stromal cells.
 ...
PMID:The ciliary neurotrophic factor and its receptor, CNTFR alpha. 1081 68

The biological actions of interleukin-6 (IL-6), leukemia inhibitory factor (LIF), and ciliary neurotrophic factor (CNTF) are mediated via respective functional receptor complexes consisting of a common signal-transducing component, gp130, and other specific receptor components, IL-6 receptor alpha (IL-6R), LIF receptor beta (LIFR), and CNTF receptor alpha (CNTFR). IL-6, LIF, and CNTF are implicated in skeletal muscle regeneration. However, the cell populations that express these receptor components in regenerating muscles are unknown. Using in situ hybridization histochemistry, we examined spatiotemporal expression patterns of gp130, IL-6R, LIFR, and CNTFR mRNAs in regenerating muscles after muscle contusion. At the early stages of regeneration (from 3 hr to Day 2 post contusion), significant signals for gp130 and LIFR mRNAs were detected in myonuclei and/or nuclei of muscle precursor cells (mpcs) and in mononuclear cells located in extracellular spaces between myofibers after muscle contusion, but IL-6R mRNA was expressed only in mononuclear cells. At Day 7 post contusion, signals for gp130, LIFR, and IL-6R mRNAs were not detected in newly formed myotubes, whereas the CNTFR mRNA level was upregulated in myotubes. These findings suggest that the upregulation of receptor subunits in distinct cell populations plays an important role in the effective regeneration of both myofibers and motor neurons. (J Histochem Cytochem 48:1203-1213, 2000)
 ...
PMID:Gene expression of receptors for IL-6, LIF, and CNTF in regenerating skeletal muscles. 1095 Aug 77

The mRNA levels of neuropoietic cytokines, ciliary neurotrophic factor (CNTF), leukemia inhibitory factor (LIF), and interleukin-6 (IL-6), and their receptor components (CNTFR alpha, LIFR beta, IL-6R alpha, and gp130) were examined in seventy-six patients with various peripheral neuropathies to determine the extent of expression of these cytokines and receptors, and their relationship to nerve fiber pathology and cell infiltration in the diseased nerves. The CNTF mRNA levels were significantly decreased in the diseased nerves and were correlated to residual myelinated fiber population. In contrast, the mRNA levels of LIF, IL-6 and the ligand-binding receptor components (CNTFR alpha, LIFR beta and IL-6R alpha) were elevated to variable extent in the diseased nerves. The CNTFR alpha, LIFR beta, and IL-6R alpha mRNA levels showed a weak positive correlation with the extent of demyelinating pathology and their levels were related to each other. Moreover, the CNTF and LIF mRNA levels were inversely proportional to the extent of macrophage invasion, whereas the CNTFR alpha and IL-6R alpha mRNA expressions were correlated to the increase in macrophage infiltration. The neuropoietic cytokine family and its receptor expressions in the diseased human nerves are regulated by an underlying pathology-related process rather than type of diseases, and could play a role in peripheral nerve regeneration and repair.
 ...
PMID:Expression of mRNAs for ciliary neurotrophic factor (CNTF), leukemia inhibitory factor (LIF), interleukin-6 (IL-6), and their receptors (CNTFR alpha, LIFR beta, IL-6R alpha, and gp130) in human peripheral neuropathies. 1135 82

The cytokines that signal through the common receptor subunit gp130, including ciliary neurotrophic factor (CNTF), interleukin-6, leukemia inhibitory factor (LIF) and oncostatin M, have pleiotropic functions in CNS development. Given the restricted expression domain of the CNTF receptor alpha (CNTFR) in the developing forebrain germinal zone and adult forebrain periventricular area, we have examined the putative role of CNTFR/LIFR/gp130-mediated signaling in regulating forebrain neural stem cell fate in vivo and in vitro. Analysis of LIFR-deficient mice revealed that a decreased level of LIFR expression results in a reduction in the number of adult neural stem cells. In adult LIFR heterozygote (+/-) mice, the number of neural stem cells and their progeny in the forebrain subependyma and TH-immunoreactive neurons in the olfactory bulb were significantly reduced. Intraventricular infusion of CNTF into the adult mouse forebrain, in the absence or presence of epidermal growth factor (EGF), enhanced self-renewal of neural stem cells in vivo. Analyses of EGF-responsive neural stem cells proliferating in vitro found that CNTF inhibits lineage restriction of neural stem cells to glial progenitors, which in turn results in enhanced expansion of stem cell number. These results suggest that CNTFR/LIFR/gp130-mediated signaling supports the maintenance of forebrain neural stem cells, likely by suppressing restriction to a glial progenitor cell fate.
 ...
PMID:The ciliary neurotrophic factor/leukemia inhibitory factor/gp130 receptor complex operates in the maintenance of mammalian forebrain neural stem cells. 1156 54

Ciliary neurotrophic factor (CNTF) is a member of the gp130 family of cytokines. The functional receptor complex of CNTF is composed of the CNTF receptor alpha (CNTFR), gp130 and the leukemia inhibitory factor receptor (LIFR). Three regions on CNTF have been identified as binding sites for its receptors. The ligand-receptor interactions are mediated through the cytokine binding domains (CBDs) and/or the immunoglobulin-like domains of the receptors. However, in the case of CNTF, the precise nature of the protein-protein contacts in the signaling complex has not yet been resolved. In this study, we provide the first demonstration that the membrane distal CBD (CBD1) of LIFR associates in vitro with soluble CNTFR in the absence of CNTF. Moreover, purified CBD1 partially blocks CNTF signaling, but not that of interleukin-6 or LIF, in human embryonal carcinoma cell line Ntera/D1 cells. These data raise the possibility that LIFR has the capability to form a ligand-free complex with CNTFR.
 ...
PMID:Membrane distal cytokine binding domain of LIFR interacts with soluble CNTFR in vitro. 1194 54

Human ciliary neurotrophic factor (CNTF) is a neurotrophic cytokine that exerts a neuroprotective effect in multiple sclerosis and amyotrophic lateral sclerosis. Clinical application of human CNTF, however, was prevented by high toxicity at higher dosages. Human CNTF elicits cellular responses by induction of a receptor complex consisting of the CNTF alpha-receptor (CNTFR), which is not involved in signal transduction, and the beta-receptors gp130 and leukemia inhibitory factor receptor (LIFR). Previous studies with rat CNTF demonstrated that rat CNTF is unable to interact with the human interleukin-6 alpha-receptor, whereas at high concentrations, it can directly induce a signaling heterodimer of human gp130 and human LIFR in the absence of the CNTF receptor. Here, we demonstrate that human CNTF cannot directly induce a heterodimer of human gp130 and LIFR. However, human CNTF can use both the membrane-bound and the soluble human IL-6R as a substitute for its cognate alpha-receptor and thus widen the target spectrum of human CNTF. Engineering a CNTFR-specific human CNTF variant may therefore be a prerequisite to improving the safety profile of CNTF.
 ...
PMID:Signaling of human ciliary neurotrophic factor (CNTF) revisited. The interleukin-6 receptor can serve as an alpha-receptor for CTNF. 1264 74

Ciliary neurotrophic factor (CNTF) signals via a tripartite receptor complex consisting of the glycosyl-phosphatidylinositol (GPI)-anchored CNTF receptor (CNTF-R), the leukaemia inhibitory factor receptor (LIF-R) and the interleukin-6 (IL-6) signal transducer gp130. We have recently reported that gp130 is endogenously expressed in the polarised epithelial model cell line Madin-Darby canine kidney (MDCK) and we have demonstrated a preferential basolateral localisation of this protein. In the present study we show that MDCK cells also express the LIF-R and respond to stimulation with human LIF by activation of tyrosine phosphorylation of signal transducer and activator of transcription-3 (STAT3), both however in an unpolarised fashion. This suggests that MDCK cells may be target cells for LIF. We have furthermore stably expressed the human CNTF-R in MDCK cells and by two different assays we found an apical localisation. Consistent with these findings, stimulation of CNTF-R-positive cells resulted only in an activation of STAT3 when CNTF was added apically. These data demonstrate that each subunit of the CNTF receptor complex has a distinct distribution in polarised cells which may reflect the different roles the respective cytokines play in vivo. Since it is currently believed that lipid rafts are involved in signal transduction as well as protein sorting we studied the association of the three receptor complex components with membrane rafts using different protocols. Whereas the CNTF-R cofractionated quantitatively with lipid rafts independently of the method used, gp130 and the LIF-R were found to associate with lipid rafts only partially when detergents were used for isolation. These findings could indicate that either the three receptor complex subunits are localised to the same kind of raft but with different affinities to the liquid-ordered environment, or that they are localised to different types of rafts. CNTF-, LIF-, and IL-6-dependent STAT3 activation was sensitive to the cholesterol-depleting drug methyl-beta-cyclodextrin (MCD) suggesting that the integrity of lipid rafts is important for IL-6-type cytokine-induced STAT activation.
 ...
PMID:Polarity and lipid raft association of the components of the ciliary neurotrophic factor receptor complex in Madin-Darby canine kidney cells. 1505 6

The cytokines of the interleukin-6 family are multifunctional proteins that regulate cell growth, differentiation, and other cell functions in a variety of biological systems including the immune, inflammatory, hematopoietic, and nervous systems. One member of this family, ciliary neurotrophic factor (CNTF), displays biological functions more restricted to the neuromuscular axis. We have recently identified two additional ligands for the CNTF receptor complex. Both are composite cytokines formed by cardiotrophin-like cytokine (CLC) associated to either the soluble type I cytokine receptor CLF or the soluble form of CNTF receptor alpha (CNTFRalpha). The present study was aimed at analyzing the interactions between the cytokine CLC and its different receptor chains. For this purpose, we modeled CLC/receptor interactions to define the residues potentially involved in the contact sites. We then performed site-directed mutagenesis on these residues and analyzed the biological interactions between mutants and receptor chains. Importantly, we found that CLC interacts with the soluble forms of CNTFRalpha and CLF via sites 1 and 3, respectively. For site 1, the most crucial residues involved in the interaction are Trp67, Arg170, and Asp174, which interact with CNTFRalpha. Surprisingly, the residues that are important for the interaction of CLC with CLF are part of the conserved FXXK motif of site 3 known to be the interaction site of LIFRbeta. Obtained results show that the Phe151 and Lys154 residues are effectively involved in the interaction of CLC with LIFRbeta. This study establishes the molecular details of the interaction of CLC with CLF, CNTFRalpha, and LIFRbeta and helps to define the precise role of each protein in this functional receptor complex.
 ...
PMID:Two different contact sites are recruited by cardiotrophin-like cytokine (CLC) to generate the CLC/CLF and CLC/sCNTFRalpha composite cytokines. 1527 19


<< Previous 1 2 3 Next >>