Biomedical subjects

T Kishimoto

Publications and source records attributed to T Kishimoto.

At least 19 recordsLinked to original sources

PubMed1992

Functional inhibition of hematopoietic and neurotrophic cytokines by blocking the interleukin 6 signal transducer gp130.

Functional pleiotropy and redundancy are characteristic features of cytokines. To understand the signaling mechanisms of such cytokines, we have proposed a two-chain interleukin (IL) 6 receptor model: IL-6 triggers the association of a ligand-binding chain (IL-6 receptor) and a nonbinding signal transducer (gp130) to form a high-affinity receptor complex, resulting in transmission of the signal by the cytoplasmic portion of gp130. This model would explain the functional redundancy of cytokines if we were to assume that gp130 interacts with several different receptor chains. Here we present data indicating that gp130 functions as a common signal transducer for IL-6, oncostatin M, leukemia inhibitory factor, and ciliary neurotrophic factor. We show that anti-gp130 monoclonal antibodies completely block the biological responses induced by all of these factors. Since leukemia inhibitory factor functions as a cholinergic differentiation factor in nerve cells, as does ciliary neurotrophic factor, these results suggest that gp130 may also play a role in the nervous system.

Animals↗

PubMed1992

Relationship between tissue content of TC-81 and relaxation of rat aorta.

This study dealt with the relationship between the relaxant action of TC-81, a new Ca2+ antagonist, and its distribution in rat aorta depolarized by high K+ (65.4 mM). The inhibitory effect by TC-81 on K(+)-induced contraction and 45Ca2+ uptake was strongly time-dependent. TC-81 and nicardipine, each 10(-9) M, produced gradual relaxation of high-K(+)-induced contraction. The tissue contents of TC-81 and nicardipine increased with time courses that reflected decreasing tension. Both the maximum tissue content of TC-81 and the maximum relaxation were significantly greater than those for nicardipine. Also, the relaxations produced by TC-81 and nicardipine were correlated with the logarithm of the content of each drug in muscle tissues. However, the dissociation of TC-81 from the tissues was slower than that of nicardipine. The data suggest that the action of TC-81 is closely related to a gradual distribution of drug into muscle tissue, resulting in a slow onset of action. Also, the saturation time of TC-81 was longer than that of nicardipine, thereby accounting for the greater relaxation with TC-81.

Animals↗

PubMed1992

Role of leucine residues in the C-terminal region of human interleukin-6 in the biological activity.

Site-directed mutagenesis of two sets of three periodic leucine residues which appear at every seventh position in the C-terminal region of human interleukin-6 (IL-6) was performed. Both receptor-binding and immunoglobulin (Ig)-induction activities of a triple mutant Leu168,175,182-->Val were only 1% compared with those of wild-type IL-6. However, the mutant Leu152,159,166-->Val had 13% receptor-binding and 2% Ig-induction activities of those of wild-type IL-6. In order to obtain more direct information on the receptor-binding region, we prepared two synthetic peptides. A significant binding activity was observed for the peptide Leu168-Met185, but not for the peptide Leu152-Arg169. These results indicate that leucine residues in the C-terminal region, especially Leu168, Leu175, and Leu182, play an important role in the receptor-binding and Ig-induction activities.

Amino Acid Sequence↗

PubMed1992

Interleukin-6 and its receptor: a paradigm for cytokines.

Many cytokines and cytokine receptors involved in the regulation of hematopoiesis, immune responses, and inflammation have been identified and characterized at the molecular level. Several characteristic features of cytokines, such as pleiotropy and redundancy, are now more clearly understood on the basis of their molecular structures. Accumulating evidence has demonstrated an intimate link between cytokines and various diseases such as allergy, autoimmune diseases, and cancer. The pathogenesis of these diseases and therapies to treat them will be discussed based on insights derived from cytokine research.

Cytokines↗

PubMed1992

p13suc1 suppresses the catalytic function of p34cdc2 kinase for intermediate filament proteins, in vitro.

The regulation of p34cdc2 kinase activity controls the entry into and exit from mitosis. Although genetic and biochemical evidence suggested close interactions between cyclins, p13suc1 and p34cdc2 kinase, the roles of p13suc1 on p34cdc2 kinase functions remain unclear. To examine the effects of p13suc1 on p34cdc2 kinase function we developed a simple purification procedure for p34cdc2 kinase, unassociated with p13suc1. The key to the purification procedures we used was buffer containing 0.5 M NaCl and 50% ethylene glycol, as a specific elutant of p34cdc2 kinase from p13suc1-Sepharose. This purified p34cdc2 kinase stoichiometrically phosphorylated vimentin and desmin. Exogenous p13suc1 suppressed the phosphorylation of these filament proteins by the kinase and prevented disassembly, although histone H1 phosphorylation was not affected. Peptide mapping analysis showed a similar extent of inhibition by p13suc1 for all five phosphorylation sites by p34cdc2 kinase of vimentin and desmin, hence these p13suc1-induced inhibitions are probably not site-specific. It thus appears that p13suc1 has a selective effect on the catalytic activity of p34cdc2 kinase for these filament proteins.

Amino Acid Sequence↗

PubMed1992

Interleukin-6 signal transducer gp130 mediates oncostatin M signaling.

Oncostatin M (OM) is a multifunctional cytokine that is structurally and functionally related to interleukin 6 (IL-6) and leukemia inhibitory factor (LIF). The specific receptor for OM has been demonstrated (by chemical cross-linking) to be a 150-kDa protein in a number of cell lines. The IL-6 signal transducer, gp130, is also an affinity converter for the LIF receptor. It does not bind to either IL-6 or LIF, but associates with the alpha subunits of the receptors and transduces the signals. We examined the possible involvement of gp130 in OM binding and signaling. We demonstrate that: (a) anti-gp130 monoclonal antibodies (mAbs) block the inhibitory effect of OM on A375 cell growth, (b) the binding and cross-linking of 125I-OM to H2981 cells are completely abolished by anti-gp130 mAbs, (c) the cross-linked OM-receptor complex is immunoprecipitated by anti-gp130 mAbs, and (d) COS-7 cells transfected with the full-length cDNA encoding gp130 exhibit increased OM binding and cross-linking, which are also blocked by anti-gp130 mAbs. Therefore, we conclude that the 150-kDa OM binding protein previously characterized in a variety of cell lines is gp130. OM is the natural ligand for gp130 and gp130 mediates the biological responses of OM.

Animals↗

PubMed1992

Interleukin-6 production in high-grade B lymphomas: correlation with the presence of malignant immunoblasts in acquired immunodeficiency syndrome and in human immunodeficiency virus-seronegative patients.

The mechanisms leading to malignant cell proliferation may differ between the different histologic forms of high-grade non-Hodgkin's lymphomas. To analyze the potential role of interleukin-6 (IL-6) as a growth factor for lymphomatous cells in these different forms, the in situ production of this cytokine was analyzed in lymphomatous samples taken from 24 patients, 18 of whom were human immunodeficiency virus (HIV) infected. Eleven Burkitt's lymphomas (BLs), seven diffuse large-cell lymphomas, and six immunoblastic lymphomas were studied. In situ hybridization experiments showed that the IL-6 gene was expressed in all tissues. The number of IL-6 gene-expressing cells was 7 times higher in the non-BLs than in the BLs, and it was 17 times higher than that of 14 control lymph nodes displaying a benign follicular hyperplasia. Analysis of individual cases indicated that the level of IL-6 gene expression was strongly correlated with the presence of immunoblasts within the malignant clone. In contrast, this level was not correlated with the presence of Epstein-Barr virus genome in the lymphoma or with the HIV status of patients. Immunohistochemical studies with an anti-IL-6 monoclonal antibody showed that IL-6 was produced in non-BLs, but not in BLs. In the former, IL-6 mainly originated from reactive, nonmalignant cells. Immunohistochemical analyses of non-BLs also showed that malignant cells produced the 80-Kd chain of the IL-6 receptor. Taken together, these results suggest that IL-6 may act as a growth factor in some forms of high-grade B lymphomas. The presence of immunoblasts may be an indicator of such forms.

Acquired Immunodeficiency Syndrome↗

PubMed1992

Transfer of multiple sclerosis into severe combined immunodeficiency mice by mononuclear cells from cerebrospinal fluid of the patients.

To investigate the mode of the pathogenesis of multiple sclerosis (MS), we transferred cerebrospinal fluid (CSF) cells, predominantly mononuclear cells, from MS patients at both exacerbation and remission stages of the disease into severe combined immunodeficiency mice by intracisternal injection. As controls, (i) CSF cells from patients with cervical spondylosis and (ii) peripheral blood mononuclear cells from normal individuals were transferred. Four to 6 weeks after transfer, most mice transferred with CSF cells from MS patients at the exacerbation stage of the disease developed paralysis and ataxia. The histopathological examination on the sacrificed mice revealed multiple scattered, discrete lesions localized in the white matter of the brainstems and spinal cords. These lesions were characterized by various degrees of tissue necrosis, involving inflammatory-cell infiltration. Most infiltrating cells were macrophages, although a smaller number of granulocytes appeared in several foci. Reactive astrocytic gliosis was also seen around the necrotic foci. Furthermore, these lesions exhibited demyelination. These histopathological changes are similar to those seen in MS. In contrast, none of the severe combined immunodeficiency mice transferred with CSF cells from MS patients at the remission stage of the disease, or with CSF cells from the patients with cervical spondylosis, or with peripheral blood mononuclear cells from normal individuals showed any such histopathological changes. These observations provide convincing direct evidence of encephalitogenicity of mononuclear cells in CSF from MS patients at the exacerbation stage of the disease.

Animals↗

PubMed1992

CNTF and LIF act on neuronal cells via shared signaling pathways that involve the IL-6 signal transducing receptor component gp130.

Ciliary neurotrophic factor (CNTF) has a variety of actions within the nervous system. While some of the actions of leukemia inhibitory factor (LIF) on neurons resemble those of CNTF, LIF also has broad actions outside of the nervous system that in many cases mimic those of interleukin-6 (IL-6). Comparison of the tyrosine phosphorylations and gene activations induced by CNTF and LIF in neuron cell lines reveals that they are indistinguishable and also very similar to signaling events that characterize LIF and IL-6 responses in hematopoietic cells. We provide a basis for the overlapping actions of these three factors by demonstrating that the shared CNTF and LIF signaling pathways involve the IL-6 signal transducing receptor component gp130. Thus, the receptor system for CNTF is surprisingly unlike those used by the nerve growth factor family of neurotrophic factors, but is instead related to those used by a subclass of hematopoietic cytokines.

Animals↗

PubMed1992

Molecular cloning of a murine IL-6 receptor-associated signal transducer, gp130, and its regulated expression in vivo.

The IL-6R system comprises two functionally different chains: a ligand binding-chain (IL-6R) and a non-ligand-binding but signal-transducing chain (gp130). gp130 associates with the IL-6-IL-6R complex, resulting in the formation of high-affinity IL-6 binding sites, and transduces the signal. A cDNA for murine gp130 has been cloned from the cDNA library of murine macrophages by using a human gp130 cDNA as a probe. The overall homology with human gp130 was 76.8% at the protein level. The extracellular region of murine gp130, as observed in human gp130, comprises 6 U of a fibronectin type III module and part of this region of approximately 200 amino acids has typical features of a cytokine receptor family. Cloned murine gp130 could transduce the growth signal in a murine IL-3-dependent cell line in response to a complex of IL-6 and soluble IL-6R. Two species of murine gp130 mRNA (7 and 10 kb) were expressed in almost all the cell lines. These transcripts were also ubiquitously expressed in murine tissues, embryonic stem cells, and embryos as early as day 6 of gestation. Administration of IL-6 in mouse caused up-regulation of the gp130 mRNA levels in several tissues. Both gp130 and IL-6R mRNA in liver were up-regulated in vivo by IL-6.

Amino Acid Sequence↗

PubMed1992

Two forms of the low-affinity Fc receptor for IgE differentially mediate endocytosis and phagocytosis: identification of the critical cytoplasmic domains.

We have previously identified two species of the low-affinity human Fc receptor for IgE, Fc epsilon RIIa and Fc epsilon RIIb, which differ only in a short stretch of amino acids at the N-terminal cytoplasmic end. Their differential expressions on B cells and monocytes suggest that Fc epsilon RIIa and Fc epsilon RIIb are involved in B-cell function and IgE-mediated immunity, respectively. Here we show that Fc epsilon RII-mediated endocytosis is observed only in Fc epsilon RIIa-expressing cells, whereas IgE-dependent phagocytosis is observed only in Fc epsilon RIIb-expressing cells, demonstrating the functional difference between Fc epsilon RIIa and Fc epsilon RIIb. Furthermore, site-directed mutagenesis revealed that the tyrosine residue in the Fc epsilon RIIa-specific region is important for endocytosis, and the Asn-Pro residues in the Fc epsilon RIIb-specific region are required for phagocytosis. These findings suggest that endocytosis and phagocytosis are functionally separable phenomena involving distinct amino acid residues.

Amino Acid Sequence↗

PubMed1992

Intensity of exposure to asbestos in metropolitan Kure City as estimated by autopsied cases.

In this study, the intensity of exposure to asbestos was evaluated in the residents of Kure City, the site of the Japanese naval shipyard, Kure. The number of asbestos bodies was counted in 728 autopsied cases from those treated surgically in Kure Kyosai Hospital. Five grams of lung tissue was lysed, and the number of asbestos bodies was counted with the use of light microscopic examination. By this method, the number of asbestos bodies detected in men was significantly higher than that in women. There was a peak between 60 and 70 years of age. The number of asbestos bodies in exposed cadavers in Kure City exceeded greatly that found in other districts of Japan. By this criterion, 58 of 109 patients with lung cancer had asbestos exposure, and 39 had a high exposure to asbestos. All 13 patients with malignant mesothelioma had a high exposure to asbestos. Excess asbestos exposure also was found in a large proportion of patients with gastric cancer, colon cancer, and acute leukemia. The crocidolite type of asbestos was detected frequently in patients of malignant mesothelioma or leukemia, and the chrysotile form was found in those with lung cancer.

Adult↗

PubMed1992

A new highly sensitive immunoassay for cytokines by dissociation-enhanced lanthanide fluoroimmunoassay (DELFIA).

Non-isotopic immunoassays for human tumor necrosis factor alpha (TNF alpha) and human interleukin-6 (IL-6) were established by employing the dissociation-enhanced lanthanide fluoroimmunoassay (DELFIA) system based on the time-resolved fluoroimmunoassay technique with europium-labeled antibody. Compared to enzyme-linked immunosorbent assays and bioassays, the sensitivity and range of measurement were significantly increased by applying the DELFIA systems to TNF alpha and IL-6. TNF alpha was measurable from 100 fg/ml to 10 ng/ml with the TNF alpha-DELFIA and IL-6 was measurable from 100 fg/ml to 1 ng/ml with the IL-6-DELFIA.

Antibodies, Monoclonal↗

PubMed1992

Human soluble IL-6 receptor: its detection and enhanced release by HIV infection.

By using a fluorescence sandwich ELISA for the quantification of soluble human IL-6R, normal human PBMC were found to be induced to release IL-6R into culture supernatant by stimulation with PHA. Furthermore, certain promonocyte cell lines and human T-cell leukemia virus I (HTLV-I)-positive cell lines produced sIL-6R into culture supernatants constitutively. However, this was not found with HTLV-I negative T cell lines and Burkitt's B cell line. In addition, generation of supernatant IL-6R of the promonocyte cell line was significantly increased 27-fold after PMA treatment and sevenfold after infection with HIV. The released IL-6R molecules were characterized as an apparent m.w. of 50 to 55 kDa by both size-exclusion HPLC and immunoprecipitation of the soluble protein with IL-6R-specific mAb followed by SDS-PAGE analysis. Furthermore, increased levels of serum IL-6R were detected in blood donors seropositive for HIV. Moreover, the released IL-6R could bind efficiently to purified rIL-6 on solid phase and suppressed the proliferative responses of PBMC. These results suggest that the release of soluble IL-6R might be linked to regulatory functions of immune responses induced by IL-6 stimulation during normal and human retrovirus-infected cell growth and differentiation.

Enzyme-Linked Immunosorbent Assay↗

PubMed1992

Characterization of the promoter region of the murine fibroblast growth factor receptor 1 gene.

To obtain some clue for the regulatory mechanism by which fibroblast growth factor (FGF) receptor 1 (FGFR 1) gene is expressed, we have cloned the promoter region of this gene from genomic library of mouse FGF-responsive cell lines. The genomic clone isolated here includes the FGFR 1 gene from position -868 to +697 relative to transcription initiation site. Sequence analysis reveals the presence of various consensus sequences for the binding sites of transcriptional factors such as SP 1, GCF, Oct-I, AP 1 and AP 2, but the absence of TATA and CAAT sequence motif. The transfection of this promoter-CAT constructs into NIH 3T3 cells demonstrates its promoter activity which is at least located between base -106 and +104.

3T3 Cells↗

PubMed1992

Oncostatin M as a potent mitogen for AIDS-Kaposi's sarcoma-derived cells.

Oncostatin M, a cytokine produced by activated lymphoid cells, regulates the growth and differentiation of a number of tumor and normal cells. In contrast to its effects on normal endothelial and aortic smooth muscle cell cultures, Oncostatin M was a potent mitogen for cells derived from acquired immunodeficiency syndrome-related Kaposi's sarcoma (AIDS-KS). After exposure to Oncostatin M, AIDS-KS cells assumed a spindle morphology, had an increased ability to proliferate in soft agar, and secreted increased amounts of interleukin-6. Oncostatin M RNA and immunoreactive Oncostatin M protein were found in AIDS-KS-derived cell isolates. These results suggest that Oncostatin M may play a role in the pathogenesis of AIDS-KS.

Acquired Immunodeficiency Syndrome↗

PubMed1992

A member of the C/EBP family, NF-IL6 beta, forms a heterodimer and transcriptionally synergizes with NF-IL6.

Using a DNA probe from the DNA-binding portion of the NF-IL6 gene and an antibody against the DNA-binding domain of NF-IL6, we isolated a gene homologous to NF-IL6 in the DNA-binding and leucine zipper domains. This intronless gene, termed NF-IL6 beta encodes a 269-amino acid protein with a potential leucine zipper structure, and the gene product can bind to the CCAAT homology as well as the viral enhancer core sequence, as in the cases of NF-IL6 and C/EBP. This gene is expressed at an undetectable or a minor level in normal tissues but is induced by lipopolysaccharide or inflammatory cytokines, as in the case of NF-IL6. NF-IL6 beta easily forms a heterodimer with NF-IL6 in vitro and the heterodimeric complex binds to the same DNA sequence as the respective homodimers. When examined by transient luciferase assays, NF-IL6 beta is consistently a stronger transactivator than NF-IL6. Furthermore, NF-IL6 beta shows a synergistic transcriptional effect with NF-IL6. These data suggest that NF-IL6 beta is an important transcriptional activator in addition to NF-IL6 in regulation of the genes involved in the immune and inflammatory responses.

Amino Acid Sequence↗

PubMed1992

A stromal cell-specific monoclonal antibody augments the stromal cell-dependent B lymphopoiesis.

We produced the mAb R25 against the stromal cell line ST2, which could support B lymphopoiesis in vitro. R25 enhanced the ability of ST2 to support B lymphopoiesis and precipitated molecules of 110 and 120 kDa (p110/120) from ST2 cell lysates. p110/120 were also expressed on other stromal and fibroblast cell lines but not on freshly isolated bone marrow hematopoietic cells, spleen cells, and lymphoid cell lines. However, R25 had no or weak effect on the stromal cell-dependent myelopoiesis. Even under conditions in which bone marrow cells were separated from stromal cells with a membrane filter, R25 could augment the stromal cell-dependent B lymphopoiesis. However, R25 did not induce the increase of IL-7 mRNA of ST2 cells. Taken together, these findings suggest that the stromal cell surface molecules p110/120 are involved in the stromal cell-dependent B lymphopoiesis and that certain soluble factors distinct from IL-7 may contribute to the p110/120-mediated B cell generation.

Animals↗