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S Rose-John

Publications and source records attributed to S Rose-John.

At least 73 records · Page 4Linked to original sources
PubMed1999

Neural activities of IL-6-type cytokines often depend on soluble cytokine receptors.

Cytokines of the interleukin-6 (IL-6) family participate in regulatory and inflammatory processes within the nervous system. IL-6, ciliary neurotrophic factor (CNTF) and IL-11 act via specific membrane receptors which, together with their ligands, associate with signal-transducing receptor subunits thereby initiating cytoplasmic signalling. Cells which only express signal-transducing receptor subunits but no ligand binding subunits for IL-6, CNTF and IL-11 are refractory to these cytokines. An unusual feature of the IL-6 cytokine family is that the soluble forms of the ligand binding receptor subunits generated by one cell type in complex with their ligands can directly stimulate the signal-transducing receptor subunits on different cell types which lack ligand binding receptor subunits. This process has been named transsignalling. This article focuses on the importance of transsignalling events in neuronal differentiation and survival responses.

Animals↗
PubMed1999

The IL-6/sIL-6R fusion protein hyper-IL-6 promotes neurite outgrowth and neuron survival in cultured enteric neurons.

The undisturbed development of the enteric nervous system depends on the supply of various neurotrophic factors during ontogenesis. Besides glial cell line-derived neurotrophic factor (GDNF), leukemia inhibitory factor (LIF) and ciliary neurotrophic factor (CNTF) take part in its development. CNTF and LIF belong to the interleukin-6 (IL-6) family of cytokines. The combination of IL-6 and the soluble IL-6 receptor accelerates peripheral nerve regeneration. In this study, we examined the effect of the fusion protein Hyper-IL-6, which consists of IL-6 and the soluble receptor sIL-6R, on neurite outgrowth and neuronal survival in vitro. Myenteric plexus of newborn rats was dissected and dissociated. Cells were grown in either serum-free chemically defined medium alone or medium supplemented with sIL-6R, IL-6, sIL-6+IL-6, Hyper-IL-6, CNTF, LIF, or GDNF. Average neurite outgrowth per neuron was highest in GDNF-treated and Hyper-IL-6-treated cultures. The number of neurite-bearing neurons was reduced in GDNF cultures compared with Hyper-IL-6-treated cells, so that the total neurite outgrowth was maximal after Hyper-IL-6 stimulation. Hyper-IL-6 furthermore stimulated neuronal survival and morphologic differentiation of the enteric glia.

Animals↗
PubMed1999

TGF-beta1 in liver fibrosis: an inducible transgenic mouse model to study liver fibrogenesis.

Transforming growth factor-beta1 (TGF-beta1) is a powerful stimulus for collagen formation in vitro. To determine the in vivo effects of TGF-beta1 on liver fibrogenesis, we generated transgenic mice overexpressing a fusion gene [C-reactive protein (CRP)/TGF-beta1] consisting of the cDNA coding for an activated form of TGF-beta1 under the control of the regulatory elements of the inducible human CRP gene promoter. Two transgenic lines were generated with liver-specific overexpression of mature TGF-beta1. After induction of the acute phase response (15 h) with lipopolysaccharide (100 microgram ip), plasma TGF-beta1 levels reached >600 ng/ml in transgenic animals, which is >100 times above normal plasma levels. Basal plasma levels of uninduced transgenic animals were about two to five times above normal. As a consequence of hepatic TGF-beta1 expression, we could demonstrate marked transient upregulation of procollagen I and procollagen III mRNA in the liver 15 h after the peak of TGF-beta1 expression. Liver histology after repeated induction of transgene expression showed an activation of hepatic stellate cells in both transgenic lines. The fibrotic process was characterized by perisinusoidal deposition of collagen in a linear pattern. This transgenic mouse model gives in vivo evidence for the important role of TGF-beta1 in stellate cell activation and liver fibrogenesis. Due to the ability to control the level of TGF-beta1 expression, this model allows the study of the regulation and kinetics of collagen synthesis and fibrolysis as well as the degree of reversibility of liver fibrosis. The CRP/TGF-beta1 transgenic mouse model may finally serve as a model for the testing of antifibrogenic agents.

Animals↗
PubMed1999

New developments in IL-6 dependent biology and therapy: where do we stand and what are the options?

Interleukin-6 (IL-6) is a four-helical protein which, on target cells, binds to a specific IL-6-receptor and two molecules of the promiscuous signal transducing protein gp130. Structure-function analysis defined three molecular contact sites between IL-6 and its receptor subunits. Using this information, competitive antagonistic proteins as well as hyperagonistic proteins were developed. Possible therapeutic applications of IL-6 antagonists are in IL-6 dependent haematological disorders (Castleman's disease, POEMS syndrome, multiple myeloma) and bone diseases (Paget's disease, osteoporosis). Designer IL-6 antagonists could suppress inflammatory activity in rheumatic and autoimmune diseases and could prevent secondary amyloidosis. IL-6 antagonists could also prove advantageous in myocardial infarction and unstable angina pectoris. IL-6 antagonists might slow down development of (mesangioproliferative) glomerulonephritis. On the other hand, hyperagonistic variants of IL-6 have a potential in ex vivo expansion of bone marrow stem cells and as thrombopoietic agents. They might also be developed into drugs to support liver regeneration in vivo and to treat stress-induced cardiac insufficiency.

Journal Article↗
PubMed1998

Role of IL-6 and the soluble IL-6 receptor in inhibition of VCAM-1 gene expression.

Adhesion molecules such as VCAM-1 and ICAM-1 are increased in the central nervous system (CNS) during inflammatory responses and contribute to extravasation of leukocytes across the blood-brain barrier (BBB) and into CNS parenchyma. Astrocytes contribute to the structural integrity of the BBB and can be induced to express VCAM-1 and ICAM-1 in response to cytokines such as TNF-alpha, IL-1beta, and IFN-gamma. In this study, we investigated the influence of IL-6 on astroglial adhesion molecule expression. IL-6, the soluble form of the IL-6R (sIL-6R), or both IL-6 plus sIL-6R, had no effect on VCAM-1 or ICAM-1 gene expression. Interestingly, the IL-6/sIL-6R complex inhibited TNF-alpha-induced VCAM-1 gene expression but did not affect TNF-alpha-induced ICAM-1 expression. The inhibitory effect of IL-6/sIL-6R complex was reversed by the inclusion of anti-IL-6R and gp130 Abs, demonstrating the specificity of the response. A highly active fusion protein of sIL-6R and IL-6, covalently linked by a flexible peptide, which is designated H-IL-6, also inhibited TNF-alpha-induced VCAM-1 expression. sIL-6R alone was an effective inhibitor of TNF-alpha-induced VCAM-1 due to endogenous IL-6 production. These results indicate that the IL-6 system has an unexpected negative effect on adhesion molecule expression in glial cells and may function as an immunosuppressive cytokine within the CNS.

Antigens, CD↗
PubMed1998

A new type of cytokine receptor antagonist directly targeting gp130.

The interleukin-6-type family of cytokines bind to receptor complexes that share gp130 as a common signal-transducing subunit. So far, receptor antagonists for interleukin-6-type cytokines have been constructed that still bind to the specific ligand binding subunit of the receptor complex, but have lost the ability to stimulate gp130. Such receptor antagonists compete for a specific receptor of a member of the cytokine family. Interleukin-6 only binds to gp130 when complexed with the interleukin-6 receptor that exists as a membrane bound and soluble molecule. Here we have constructed fusion proteins that consist of the soluble form of the human interleukin-6 receptor covalently linked to interleukin-6 receptor antagonists. These fusion proteins directly bind to gp130. Moreover, at concentrations of 10-50 nM they completely neutralize not only the biological activity of interleukin-6 but also of other cytokines of the interleukin-6-type family that act via gp130 homodimers or gp130/LIF-R heterodimers. Therefore, these gp130 targeting cytokine antagonists might be useful therapeutic tools in disease states that are related to cytokines of the interleukin-6 family.

Antigens, CD↗
PubMed1998

Coexpression of IL-6 and soluble IL-6R causes nodular regenerative hyperplasia and adenomas of the liver.

Studies with tumor necrosis factor p55 receptor- and interleukin-6 (IL-6)-deficient mice have shown that IL-6 is required for hepatocyte proliferation and reconstitution of the liver mass after partial hepatectomy. The biological activities of IL-6 are potentiated when this cytokine binds soluble forms of its specific receptor subunit (sIL-6R) and the resulting complex interacts with the transmembrane signaling chain gp130. We show here that double transgenic mice expressing high levels of both human IL-6 and sIL-6R under the control of liver-specific promoters spontaneously develop nodules of hepatocellular hyperplasia around periportal spaces and present signs of sustained hepatocyte proliferation. The resulting picture is identical to that of human nodular regenerative hyperplasia, a condition frequently associated with immunological and myeloproliferative disorders. In high expressors, hyperplastic lesions progress with time into discrete liver adenomas. These data strongly suggest that the IL-6/sIL-6R complex is both a primary stimulus to hepatocyte proliferation and a pathogenic factor of hepatocellular transformation.

Adenoma↗
PubMed1998

In vivo and in vitro activities of the gp130-stimulating designer cytokine Hyper-IL-6.

IL-6 is a multifactorial cytokine mediating acute inflammatory responses in the liver. When IL-6 binds to a specific receptor (IL-6R), the IL-6/IL-6R complex associates with the signal transducer gp130, initiating intracellular signaling. A soluble form of the IL-6R (sIL-6R) renders target cells sensitive to IL-6 that do not express the IL-6R on their surfaces. A designer cytokine, termed Hyper-IL-6, consisting of IL-6 covalently linked to the sIL-6R was fully active on gp130-expressing cells at 100- to 1000-fold lower concentrations than unlinked IL-6 and IL-6R. Mice were injected i.p. with Hyper-IL-6 or IL-6. Upon injection of Hyper-IL-6 into mice, the acute phase response, as measured by haptoglobin mRNA expression in the liver, was markedly increased and lasted significantly longer compared with that in mice injected with a 10-fold higher dose of IL-6 alone. On human hepatoma cells, Hyper-IL-6 caused similar effects, indicating that the longer lasting response to the fusion protein could not only be explained by the longer plasma half-life of the fusion protein. Experiments using iodinated IL-6 and Hyper-IL-6 revealed that Hyper-IL-6 bound with high affinity to gp130 and was less efficiently internalized. This effect might explain the longer lasting activity of this protein on cells. The highly active IL-6/sIL-6R designer protein might be of significant clinical importance for the stimulation of cells that are more responsive to the IL-6/sIL-6R complex than to IL-6 alone. Such cells include hemopoietic progenitor cells and hepatocytes.

Acute-Phase Reaction↗
PubMed1998

The membrane proximal cytokine receptor domain of the human interleukin-6 receptor is sufficient for ligand binding but not for gp130 association.

Interleukin-6 (IL-6) belongs to the family of the "four-helix bundle" cytokines. The extracellular parts of their receptors consist of several Ig- and fibronectin type III-like domains. Characteristic of these receptors is a cytokine-binding module consisting of two such fibronectin domains defined by a set of four conserved cysteines and a tryptophan-serine-X-tryptophan-serine (WSXWS) sequence motif. On target cells, IL-6 binds to a specific IL-6 receptor (IL-6R), and the complex of IL-6.IL-6R associates with the signal transducing protein gp130. The IL-6R consists of three extracellular domains. The NH2-terminal Ig-like domain is not needed for ligand binding and signal initiation. Here we have investigated the properties and functional role of the third membrane proximal domain. The protein can be efficiently expressed in bacteria, and the refolded domain is shown to be sufficient for IL-6 binding. When complexed with IL-6, however, it fails to associate with the gp130 protein. Since the second and the third domain together with IL-6 can bind to gp130 and induce signaling, our data demonstrate the ligand binding function of the third domain and point to an important role of the second domain in complex formation with gp130 and signaling.

Antigens, CD↗
PubMed1998

Regulation of the type II oncostatin M receptor expression in lung-derived epithelial cells.

Oncostatin M (OSM) is a potent modulator of human lung-derived epithelial cell function. This cytokine binds two distinct receptor complexes: type I OSM receptor which is also a functional receptor for leukemia inhibitory factor (LIF), and type II OSM-specific receptor. The role of these two distinct receptors in mediating the response of individual cell types to OSM has not been delineated. In contrast to LIF, OSM induces synthesis of alpha1-antichymotrypsin and alpha1-antiproteinase inhibitor in lung-derived epithelial cells. The differential responsiveness to LIF and OSM suggested that the response of lung epithelial cells to OSM may be mediated by the OSM-specific receptor. Therefore, we characterized lung-derived epithelial cells for the expression of type II OSM receptor mRNAs, and the regulation of the mRNAs encoding the components of the OSM-specific receptor by cytokines and dexamethasone.

Antigens, CD↗
PubMed1998

Sympathetic neurons can produce and respond to interleukin 6.

Neuronal expression of cytokines is an area of active investigation in the contexts of development, disease, and normal neural function. Although cultured rat sympathetic neurons respond very weakly to exogenous interleukin 6 (IL-6), we find that addition of soluble IL-6 receptor (sIL-6R) and IL-6 enhances neuronal survival in the absence of nerve growth factor. Neutralizing monoclonal antibodies against IL-6 block these effects. Addition of IL-6 and sIL-6R also induces a subset of neuropeptide and transmitter synthetic enzyme mRNAs identical to that demonstrated for leukemia inhibitory factor, ciliary neurotrophic factor, and oncostatin M. Both of these effects are duplicated by addition of a highly active fusion protein of sIL-6R and IL-6, covalently linked by a flexible peptide chain, which is designated H-IL-6. In addition, we show that sympathetic neurons produce IL-6. In situ hybridization indicates a neuronal localization of IL-6 mRNA in superior cervical ganglia, and bioactive IL-6 protein is detected in ganglion culture supernatants. Interestingly, the IL-6 produced by sympathetic neurons does not lead to survival of these cells in culture unless sIL-6R is added. Thus, sympathetic neurons can produce IL-6 and may respond to it in an autocrine/paracrine manner if sIL-6R is present. Moreover, the prior findings of sIL-6R in serum and inflammatory fluids now have added interest in the context of neuro-immune interactions.

3T3 Cells↗
PubMed1998

Recombinant human single chain Fv antibodies recognizing human interleukin-6. Specific targeting of cytokine-secreting cells.

A human antibody library was displayed on the surface of filamentous bacteriophage and screened for binding to human interleukin-6 (IL-6). Two antibody-bearing phages were selected that bound IL-6. The complementary-determining region 3 loops of the variable heavy chains of these two antibodies differed in length and sequence and recognized two distinct epitopes. One of the single chain Fv fragments isolated (H1) was found to bind human (but not murine) IL-6 with an affinity comparable to that of the human IL-6 receptor. H1 also recognized newly synthesized human IL-6 intracellularly, as shown by indirect immunofluorescence. H1 did not neutralize human IL-6, and the H1 epitope was mapped to a region of IL-6 not involved in interactions with IL-6, IL-6 receptor, or the signal-transducing protein gp130. To target IL-6-secreting cells, we then constructed a bispecific antibody fragment (a diabody) comprising H1 and the antigen binding site of the T-cell activating monoclonal antibody OKT3. The diabody led to T-cell-mediated killing of cells secreting IL-6.

Antibodies, Bispecific↗
PubMed1998

Oncostatin M, leukaemia-inhibitory factor and interleukin 6 trigger different effects on alpha1-proteinase inhibitor synthesis in human lung-derived epithelial cells.

Interleukin 6 (IL-6), oncostatin M (OSM) and leukaemia-inhibitory factor (LIF) share a common signal-transducing subunit in each of their receptors and thus mediate an overlapping spectrum of biological activities. Although all of these cytokines stimulate the production of alpha1-proteinase inhibitor (alpha1-PI) in hepatocyte-derived cells, only OSM is able to up-regulate levels of this inhibitor in epithelial cells originating from the lung. In this study we characterized human lung-derived epithelial-like HTB58 cells for their ability to synthesize alpha1-PI after treatment with IL-6, OSM and LIF. The results demonstrate that the resistance of HTB58 cells to the effects of IL-6 and LIF was not because of a lack of their individual functional receptors and suggest that OSM utilizes two different receptors, gp130/LIF receptor and gp130/OSM receptor, in lung-derived epithelial cells.

Blotting, Northern↗
PubMed1998

Soluble interleukin 6 (IL-6) receptor influences the expression of the protooncogene junB and the production of fibrinogen in the HepG2 human hepatoma cell line and primary rat hepatocytes.

Interleukin 6 (IL-6) belongs to a family of cytokines using receptors sharing a common signal-transducing chain, gp130 and containing a specific ligand-binding chain (IL-6R alpha). It was shown that both the membrane-bound and the soluble form (sIL-6R) of this ligand specific receptor chain occurs naturally. The soluble form of IL-6 receptor was found to be able to associate with the membrane-bound gp130 and to generate active IL-6 receptor complex capable of inducing signal transduction. This study on a human hepatoma cell line and primary rat hepatocytes examined how the effectiveness of IL-6 is modified by the presence of soluble IL-6 receptor and whether the sIL-6R in the absence of IL-6 acts on hepatocytes. The authors studied the gene expression of junB, a member of the Jun family of transcription factors, and the production of fibrinogen in response to IL-6 and sIL-6R. The data show that in hepatic cells, endogeneously expressing IL-6R, the IL-6 induced junB and fibrinogen expression is inhibited by the presence of sIL-6R. In addition we found that sIL-6R alone (in the absence of IL-6) induced junB mRNA expression, but had no effect on fibrinogen production.

Animals↗
PubMed1998

Hepatocellular hyperplasia, plasmacytoma formation, and extramedullary hematopoiesis in interleukin (IL)-6/soluble IL-6 receptor double-transgenic mice.

Cytokines interact not only with membrane anchored receptors, but also with specific soluble receptors which circulate in the bloodstream. In general, soluble cytokine receptors such as soluble tumor necrosis factor receptor, soluble interleukin 1 receptor, and soluble interleukin 4 receptor compete with their membrane-bound counterparts for the ligands and therefore act as antagonists. In contrast, soluble receptors for cytokines of the interleukin-6 (IL-6) family complex with their ligands act agonistically. Interestingly, the complex of IL-6 and the soluble interleukin 6 receptor (sIL-6R) activates target cells that do not express the membrane-bound IL-6R and therefore cannot respond to IL-6. To identify cellular responses that are due to IL-6/sIL-6R but not to IL-6 alone, IL-6/sIL-6R double-transgenic mice were generated and compared with IL-6 single-transgenic mice. IL-6/sIL-6R transgenic mice develop a severe phenotype showing 1) marked hepatocellular hyperplasia frequently surrounded by peliosis and necrosis, 2) significant acceleration and aggravation of plasmacytoma formation, and 3) excessive activation of extramedullary hematopoiesis in spleen and liver followed by a subsequent increase of all cellular components in the peripheral blood. These in vivo data suggest that the sIL-6R recruits primarily unresponsive cell populations such as hematopoietic progenitor cells and hepatocytes to IL-6-induced proliferation, but also enhances the known mitogenic effect of IL-6 on plasma cells and thereby contributes to plasmacytoma formation.

Animals↗