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Atsushi Ogata,
Masahide Mori,
Shoji Hashimoto,
Yukihiro Yano,
Takeya Fujikawa,
Mari Kawai,
Yusuke Kuwahara,
Toru Hirano,
Junsuke Arimitsu,
Keisuke Hagihara,
Yoshihito Shima,
Masashi Narazaki,
Souichirou Yokota, Tadamitsu Kishimoto,
Ichiro Kawase,
Toshio Tanaka
[show abstract]
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ABSTRACT: Interferon gamma (IFN-gamma) production is a critical step of antituberculosis (anti-TB) immune response. The purpose of this study was to determine the influences of biologics, including the interleukin (IL)-6 receptor-inhibitor tocilizumab (TCZ), and tumor necrosis factor (TNF) antagonists infliximab (INF) and etanercept (ETA), on Mycobacterium tuberculosis (MTB) antigen-induced IFN-gamma production. MTB antigen (ESAT-6 and CFP-10)-induced IFN-gamma-releasing assay was performed with or without addition of biologics (TCZ, ETA, and INF) using whole blood from patients with active TB. ETA and INF inhibited IFN-gamma production in a dose-dependent manner. In whole blood from TB patients, ESAT-6 stimulated significant production of IFN-gamma (1.30 +/- 1.95 IU/ml), and TCZ did not inhibit IFN-gamma production (1.56 +/- 1.88 IU/ml). IFN-gamma production by ESAT-6 was inhibited by ETA and INF (0.98 +/- 1.74, 0.75 +/- 1.66 IU/ml, respectively). CFP-10 stimulated significant production of IFN-gamma (1.46 +/- 1.60 IU/ml), and TCZ did not inhibit IFN-gamma production (1.51 +/- 1.77 IU/ml). IFN-gamma production by CFP-10 was inhibited by ETA and INF (0.91 +/- 0.99, 0.72 +/- 0.88 IU/ml, respectively). TCD did not inhibit MTB antigen-induced IFN-gamma production. As IFN-gamma production is important in antimycobacterial host defenses, the minimal influence of TCZ on IFN-gamma-releasing assay suggests a low risk of latent TB infection reactivation during tocilizumab therapy.
Modern Rheumatology 11/2009; 20(2):130-3. · 1.58 Impact Factor
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Toshio Tanaka,
Yusuke Kuwahara,
Yoshihito Shima,
Toru Hirano,
Mari Kawai,
Masako Ogawa,
Junsuke Arimitsu,
Keisuke Hagihara,
Masashi Narazaki,
Atsushi Ogata,
Ichiro Kawase, Tadamitsu Kishimoto
Arthritis & Rheumatism 11/2009; 61(12):1762-4. · 7.87 Impact Factor
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Satoshi Serada,
Minoru Fujimoto,
Atsushi Ogata,
Fumitaka Terabe,
Toru Hirano,
Hideki Iijima,
Shinichiro Shinzaki,
Teppei Nishikawa,
Tomoharu Ohkawara,
Kota Iwahori,
Nobuyuki Ohguro, Tadamitsu Kishimoto,
Tetsuji Naka
[show abstract]
[hide abstract]
ABSTRACT: To identify a novel serum biomarker of disease activity in inflammatory autoimmune disorders.
Sera obtained from rheumatoid arthritis (RA) patients before and after anti-TNF therapy were analysed by iTRAQ (isobaric tags for relative and absolute quantitation) quantitative proteomic analysis and further validated by ELISA.
Of 326 proteins identified by proteomic analysis, increased serum levels of leucine-rich alpha-2 glycoprotein (LRG) was identified in RA patients before therapy. Serum LRG concentrations were significantly elevated in RA patients compared with healthy controls and decreased after anti-TNF therapy. Furthermore, serum LRG concentrations correlated with disease activity in RA and Crohn's disease (CD). Interestingly, in a subpopulation of patients with active CD and normal C-reactive protein levels, serum LRG concentrations were elevated.
LRG represents a novel serum biomarker for monitoring disease activity during therapy in autoimmune patients, particularly useful in patients with active disease but normal CRP levels.
Annals of the rheumatic diseases 10/2009; 69(4):770-4. · 8.11 Impact Factor
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ABSTRACT: Toll-like receptor (TLR) signals perform a crucial role in innate immune responses to pathogens. In this study, we found that the aryl hydrocarbon receptor (Ahr) negatively regulates inflammatory responses mediated by lipopolysaccharide (LPS) in macrophages. Ahr was induced in macrophages stimulated by LPS, but not by transforming growth factor (TGF)-beta plus interleukin (IL)-6, which can induce Ahr in naive T cells. The production of IL-6 and tumor necrosis factor (TNF)-alpha by LPS was significantly elevated in Ahr-deficient macrophages compared with that in wild-type (WT) cells. Ahr-deficient mice were more highly sensitive to LPS-induced lethal shock than WT mice. Signal transducer and activator of transcription 1 (Stat1) deficiency, as well as Ahr deficiency, augmented LPS-induced IL-6 production. We found that Ahr forms a complex with Stat1 and nuclear factor-kappa B (NF-kappaB) in macrophages stimulated by LPS, which leads to inhibition of the promoter activity of IL-6. Ahr thus plays an essential role in the negative regulation of the LPS signaling pathway through interaction with Stat1.
Journal of Experimental Medicine 09/2009; 206(9):2027-35. · 13.85 Impact Factor
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[show abstract]
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ABSTRACT: The cloning of IL-6 cDNA in 1986 revealed that IL-6 is a multifunctional cytokine that plays important roles in the immunopathogenesis
of rheumatoid arthritis (RA). A close relationship was observed between IL-6 levels in the synovial compartment and disease
activity in RA patients, and overproduction of IL-6 could readily explain the abnormal laboratory findings and clinical symptoms
seen in these patients. IL-6 therefore appeared to be a worthwhile and attractive therapeutic target for RA. In practice,
blockage of IL-6 signalling by a humanised anti-IL-6 receptor antibody [tocilizumab (TCZ); also known as MRA] has been found
to be very effective in the treatment of patients with RA. In recent Japanese Phase III clinical studies in RA patients, TCZ
clearly prevented radiographic progression of joint destruction and greatly improved signs and symptoms. Very interestingly
and importantly, this therapy has also proved quite effective at improving fever, fatigue and anaemia. No serious adverse
events have been reported. At present, several international clinical studies of TCZ are ongoing in more than 4000 patients
with active RA in 41 countries. The results are continuing to confirm the efficacy and safety of TCZ in the treatment of patients
with RA.
05/2009: pages 45-57;
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[show abstract]
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ABSTRACT: We investigated the clinical efficacy and safety of tocilizumab (a humanized anti-IL-6 receptor antibody) monotherapy in active rheumatoid arthritis (RA) patients with an inadequate response to low dose methotrexate (MTX). In a multicenter, double-blind, randomized, controlled trial, 125 patients were allocated to receive either tocilizumab 8 mg/kg every 4 weeks plus MTX placebo (tocilizumab group) or tocilizumab placebo plus MTX 8 mg/week (control group) for 24 weeks. The clinical responses were measured using the American College of Rheumatology (ACR) criteria and the Disease Activity Score in 28 joints. Serum vascular endothelial growth factor (VEGF) levels were also monitored. At week 24, 25.0% in the control group and 80.3% in the tocilizumab group achieved ACR20 response. The tocilizumab group showed superior ACR response criteria over control at all time points. Additionally, serum VEGF levels were significantly decreased by tocilizumab treatment. The overall incidences of adverse events (AEs) were 72 and 92% (serious AEs: 4.7 and 6.6%; serious infections: 1.6 and 3.3%) in the control and the tocilizumab groups, respectively. All serious adverse events improved by adequate treatment. Tocilizumab monotherapy was well tolerated and provided an excellent clinical benefit in active RA patients with an inadequate response to low dose MTX.
Modern Rheumatology 12/2008; 19(1):12-9. · 1.58 Impact Factor
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Minoru Fujimoto,
Satoshi Serada,
Masahiko Mihara,
Yasushi Uchiyama,
Hiroto Yoshida,
Nobuo Koike,
Yoshiyuki Ohsugi,
Teppei Nishikawa,
Barry Ripley,
Akihiro Kimura, Tadamitsu Kishimoto,
Tetsuji Naka
[show abstract]
[hide abstract]
ABSTRACT: To investigate the mechanism of interleukin-6 (IL-6) blockade in autoimmune arthritis, by comparing the effect of anti-IL-6 receptor (anti-IL-6R) monoclonal antibody (mAb) treatment with the effect of soluble tumor necrosis factor (sTNFR)-Fc fusion protein treatment on T helper cell differentiation in collagen-induced arthritis (CIA).
DBA/1 mice were immunized with type II collagen (CII) to induce arthritis and were left untreated or were treated with anti-IL-6R mAb or TNFR-Fc. T helper cell differentiation and cytokine expression during the development of arthritis in these mice were analyzed.
Immunization with CII predominantly increased the frequency of Th17 cells rather than Th1 cells. The frequency of FoxP3+ Treg cells was also increased after immunization. Treatment of mice with CIA with anti-IL-6R mAb on day 0 markedly suppressed the induction of Th17 cells and arthritis development, but treatment with this antibody on day 14 failed to suppress both Th17 differentiation and arthritis. In contrast, treatment of mice with CIA with TNFR-Fc from day 0 to day 14 suppressed neither Th17 differentiation nor arthritis, but treatment from day 21 to day 35 successfully ameliorated arthritis without inhibiting Th17 induction. Neither antibody treatment increased the frequency of Treg cells.
Our results indicate that the protective effect of IL-6 blockade, but not tumor necrosis factor (TNF) blockade, in CIA correlates with the inhibition of Th17 differentiation. Our findings suggest that IL-6 blockade in rheumatoid arthritis in human is also likely to involve a therapeutic mechanism distinct from that of TNF blockade and thus may represent an alternative therapy for patients in whom the disease is refractory to TNF blockade.
Arthritis & Rheumatism 12/2008; 58(12):3710-9. · 7.87 Impact Factor
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ABSTRACT: IL-17-producing T helper cells (Th17) have been recently identified as a previously undescribed subset of helper T cells. Here, we demonstrate that aryl hydrocarbon receptor (Ahr) has an important regulatory function in the commitment of Th17 cells. Ahr was robustly induced under Th17-polarizing conditions. Ahr-deficient naïve T cells showed a considerable loss in the ability to differentiate into Th17 cells when induced by TGF-beta plus IL-6. We were able to demonstrate that Ahr interacts with Stat1 and Stat5, which negatively regulate Th17 development. Whereas Stat1 activation returned to its basal level in Ahr wild type naïve T cells 24 h after stimulation with TGF-beta plus IL-6, Stat1 remained activated in Ahr-deficient naïve T cells after stimulation. These results indicate that Ahr participates in Th17 cell differentiation through regulating Stat1 activation, a finding that constitutes additional mechanisms in the modulation of Th17 cell development.
Proceedings of the National Academy of Sciences 08/2008; 105(28):9721-6. · 9.68 Impact Factor
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Satoshi Serada,
Minoru Fujimoto,
Masahiko Mihara,
Nobuo Koike,
Yoshiyuki Ohsugi,
Shintaro Nomura,
Hiroto Yoshida,
Teppei Nishikawa,
Fumitaka Terabe,
Tomoharu Ohkawara,
Tsuyoshi Takahashi,
Barry Ripley,
Akihiro Kimura, Tadamitsu Kishimoto,
Tetsuji Naka
[show abstract]
[hide abstract]
ABSTRACT: The development of Th17 cells is a key event in the pathogenesis of experimental autoimmune encephalomyelitis (EAE), a murine model of human multiple sclerosis (MS). Previous studies have demonstrated that an IL-6-dependent pathway is involved in the differentiation of Th17 cells from naïve CD4-positive T cells in vitro. However, the role of IL-6 in vivo in the development of Th17 cells in EAE has remained unclear. In the present study, we found that IL-6 blockade by treatment with an anti-IL-6 receptor monoclonal antibody (anti-IL-6R mAb) inhibited the development of EAE and inhibited the induction of myelin oligodendrocyte glycoprotein (MOG) peptide-specific CD4-positive, CD8-positive, and Th17 T cells, in inguinal lymph nodes. Thus, the protective effect of IL-6 blockade in EAE is likely to be mediated via the inhibition of the development of MOG-peptide-specific Th17 cells and Th1 cells, which in turn leads to reduced infiltration of T cells into the CNS. These findings indicate that anti-IL-6R mAb treatment might represent a novel therapy for human MS.
Proceedings of the National Academy of Sciences 08/2008; 105(26):9041-6. · 9.68 Impact Factor
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Jiro Horino,
Minoru Fujimoto,
Fumitaka Terabe,
Satoshi Serada,
Tsuyoshi Takahashi,
Yoshihito Soma,
Kentaro Tanaka,
Takatoshi Chinen,
Akihiko Yoshimura,
Shintaro Nomura,
Ichiro Kawase,
Norio Hayashi, Tadamitsu Kishimoto,
Tetsuji Naka
[show abstract]
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ABSTRACT: Inflammatory bowel disease (IBD) is a chronic disorder of the gastrointestinal tract. Although the etiology and pathogenesis of IBD remain unknown, pro-inflammatory cytokines including IFN-gamma play an important role in the development of IBD. Suppressor of cytokine signaling-1 (SOCS-1) is a crucial inhibitor of cytokine signaling, particularly of IFN-gamma. In this study, we investigated the role of SOCS-1 in the development of murine dextran sulfate sodium (DSS)-induced colitis, a model of colitis resembling human IBD. SOCS-1 heterozygous (SOCS-1(+/-)) and wild-type (WT) mice were given 3% DSS dissolved in drinking water for 5 days. Activation and expression of signal transducers and activators of transcription (STAT) in colonic tissues were assessed by western blot analysis. The expression of CD4, IFN-gamma, IL-4, IL-17 and Forkhead box P3 (Foxp3) in colonic lamina propria lymphocytes was analyzed by flow cytometry and cytokine concentrations in serum were measured. DSS-treated SOCS-1(+/-) mice developed more severe colitis than DSS-treated WT mice. Enhanced activation of STAT1, a higher ratio of CD4(+)IFN-gamma(+) T cells and a lower frequency of Foxp3(+) regulatory T (Treg) cells, were observed in the colon of DSS-treated SOCS-1(+/-) mice compared with DSS-treated WT mice. DSS-treated SOCS-1(+/-) mice showed higher levels of IFN-gamma in sera than did DSS-treated WT mice. Furthermore, T cell-specific SOCS-1-conditional knockout mice developed more severe colitis than control mice after DSS administration. Our findings suggest that SOCS-1, particularly in T cells, prevents the development of DSS-induced colitis in mice by inhibiting IFN-gamma/STAT1 signaling and by subsequently regulating Treg cell development.
International Immunology 07/2008; 20(6):753-62. · 3.41 Impact Factor
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ABSTRACT: IL-6 is a pro-inflammatory cytokine with multiple roles in the pathogenesis of rheumatoid arthritis (RA). Targeting IL-6 with the humanized anti IL-6 receptor antibody tocilizumab was effective in several placebo-controlled clinical studies in RA.
To address how clinically efficacious blockade of IL-6 signalling with inteleukin-6 receptor antibody is in RA patients and what the potential mode of action explaining tocilizumab activity in RA treatment could be.
IL-6 induces autoantibody-producing plasma cells and effector T cells and is implicated in the development of clinical signs and symptoms, including increased synthesis of acute phase reactants, fatigue, anaemia and anorexia. Its effects also included significant improvements in American College of Rheumatology (ACR)20, ACR50 and ACR70 values, as well as in health-related quality of life measures, compared with controls. Tocilizumab also prevents radiographic progression of joint damage. Tocilizumab is generally well tolerated and efficacious in patients refractive to conventional DMARD therapies.
Expert opinion on biological therapy 06/2008; 8(5):669-81. · 3.22 Impact Factor
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Shumpei Yokota,
Tomoyuki Imagawa,
Masaaki Mori,
Takako Miyamae,
Yukoh Aihara,
Shuji Takei,
Naomi Iwata,
Hiroaki Umebayashi,
Takuji Murata,
Mari Miyoshi,
Minako Tomiita,
Norihiro Nishimoto, Tadamitsu Kishimoto
[show abstract]
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ABSTRACT: Systemic-onset juvenile idiopathic arthritis does not always respond to available treatments, including antitumour necrosis factor agents. We investigated the efficacy and safety of tocilizumab, an anti-interleukin-6-receptor monoclonal antibody, in children with this disorder.
56 children (aged 2-19 years) with disease refractory to conventional treatment were given three doses of tocilizumab 8 mg/kg every 2 weeks during a 6-week open-label lead-in phase. Patients achieving an American College of Rheumatology Pediatric (ACR Pedi) 30 response and a C-reactive protein concentration (CRP) of less than 5 mg/L were randomly assigned to receive placebo or to continue tocilizumab treatment for 12 weeks or until withdrawal for rescue medication in a double-blind phase. The primary endpoint of the double-blind phase was an ACR Pedi 30 response and CRP concentration of less than 15 mg/L. Patients responding to tocilizumab and needing further treatment were enrolled in an open-label extension phase for at least 48 weeks. The analysis was done by intention to treat. This study is registered with ClinicalTrials.gov, numbers NCT00144599 (for the open-label lead-in and double-blind phases) and NCT00144612 (for the open-label extension phase).
At the end of the open-label lead-in phase, ACR Pedi 30, 50, and 70 responses were achieved by 51 (91%), 48 (86%), and 38 (68%) patients, respectively. 43 patients continued to the double-blind phase and were included in the efficacy analysis. Four (17%) of 23 patients in the placebo group maintained an ACR Pedi 30 response and a CRP concentration of less than 15 mg/L compared with 16 (80%) of 20 in the tocilizumab group (p<0.0001). By week 48 of the open-label extension phase, ACR Pedi 30, 50, and 70 responses were achieved by 47 (98%), 45 (94%), and 43 (90%) of 48 patients, respectively. Serious adverse events were anaphylactoid reaction, gastrointestinal haemorrhage, bronchitis, and gastroenteritis.
Tocilizumab is effective in children with systemic-onset juvenile idiopathic arthritis. It might therefore be a suitable treatment in the control of this disorder, which has so far been difficult to manage.
The Lancet 03/2008; 371(9617):998-1006. · 38.28 Impact Factor
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Keiichi Iwanami,
Isao Matsumoto,
Yoko Tanaka-Watanabe,
Asuka Inoue,
Masahiko Mihara,
Yoshiyuki Ohsugi,
Mizuko Mamura,
Daisuke Goto,
Satoshi Ito,
Akito Tsutsumi, Tadamitsu Kishimoto,
Takayuki Sumida
[show abstract]
[hide abstract]
ABSTRACT: To clarify the glucose-6-phosphate isomerase (GPI)-specific CD4+ T cell lineage involved in GPI-induced arthritis and to investigate their pathologic and regulatory roles in the induction of the disease.
DBA/1 mice were immunized with GPI to induce arthritis. CD4+ T cells and antigen-presenting cells were cocultured with GPI, and cytokines in the supernatant were analyzed by enzyme-linked immunosorbent assay. Anti-interferon-gamma (anti-IFNgamma) monoclonal antibody (mAb), anti-interleukin-17 (anti-IL-17) mAb, or the murine IL-6 receptor (IL-6R) mAb MR16-1 was injected at different time points, and arthritis development was monitored visually. After MR16-1 was injected, percentages of Th1, Th2, Th17, and Treg cells were analyzed by flow cytometry, and CD4+ T cell proliferation was analyzed using carboxyfluorescein diacetate succinimidyl ester.
GPI-specific CD4+ T cells were found to be differentiated to Th1 and Th17 cells, but not Th2 cells. Administration of anti-IL-17 mAb on day 7 significantly ameliorated arthritis (P < 0.01), whereas administration of anti-IFNgamma mAb exacerbated arthritis. Neither anti-IL-17 mAb nor anti-IFNgamma mAb administration on day 14 ameliorated arthritis. Administration of MR16-1 on day 0 or day 3 protected against arthritis induction, and MR16-1 administration on day 8 significantly ameliorated existing arthritis (P < 0.05). After administration of MR16-1, there was marked suppression of Th17 differentiation, without an increase in Th1, Th2, or Treg cells, and CD4+ T cell proliferation was also suppressed.
IL-6 and Th17 play an essential role in GPI-induced arthritis. Since it has previously been shown that treatment with a humanized anti-IL-6R mAb has excellent effects in patients with rheumatoid arthritis (RA), we propose that the IL-6/IL-17 axis might also be involved in the generation of RA, especially in the early effector phase.
Arthritis & Rheumatism 03/2008; 58(3):754-63. · 7.87 Impact Factor
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ABSTRACT: As conditional knockout mice for stat3 are impaired in liver regeneration after partial hepatectomy while those for gp130 have defects in early STAT3 phosphorylation but have normal DNA synthesis, late STAT3 phosphorylation induced independently of gp130 seems to be essential for liver regeneration. Since HGF and EGF can activate STAT3 via gp130-independent MET and EGFR, respectively, we assumed that these factors account for STAT3-dependent liver regeneration. Here, we investigated this hypothesis by introducing suppressor of cytokine signaling (SOCS)-1 and SOCS3, potent negative regulators of STAT3 signaling, selectively in hepatocytes.
We generated recombinant adenoviruses expressing socs1 and socs3.
Hepatocytes infected with socs1-virus lacked STAT3 phosphorylation in response to IL-6 and HGF, while cells infected with socs3-virus lacked the response to all of IL-6, HGF and EGF, indicating that those SOCS proteins differently regulate EGFR signaling. Mice infected with socs3-virus exhibited severe and persistent impairment while those with socs1-virus showed only delayed regeneration, indicating requirement of both MET and EGFR signalings.
These results clearly demonstrated that MET- and EGFR-mediated STAT3 signalings cooperatively contribute to liver regeneration and could provide new insights into tissue homeostasis.
Journal of Hepatology 03/2008; 48(2):237-45. · 9.26 Impact Factor
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ABSTRACT: To evaluate the ability of tocilizumab (a humanised anti-IL-6 receptor antibody) monotherapy to inhibit progression of structural joint damage in patients with RA.
In a multi-centre, x ray reader-blinded, randomised, controlled trial, 306 patients with active RA of <5 years' duration were allocated to receive either tocilizumab monotherapy at 8 mg/kg intravenously every 4 weeks or conventional disease-modifying antirheumatic drugs (DMARDs) for 52 weeks. Radiographs of hands and forefeet were scored by the van der Heijde modified Sharp method.
Patients had a mean disease duration of 2.3 years and a disease activity score in 28 joints of 6.5 at baseline. Mean total modified Sharp score (TSS) was 29.4, which was very high despite the relatively short disease duration. At week 52, the tocilizumab group showed statistically significantly less radiographic change in TSS (mean 2.3; 95% CI 1.5 to 3.2) than the DMARD group (mean 6.1; 95% CI 4.2 to 8.0; p<0.01). Tocilizumab monotherapy also improved signs and symptoms. The overall incidences of AEs were 89% and 82% (serious AEs: 18% and 13%; serious infections: 7.6% and 4.1%) in the tocilizumab and DMARD groups, respectively.
Tocilizumab monotherapy was generally well tolerated and provided radiographic benefit in patients with RA.
Annals of the Rheumatic Diseases 10/2007; 66(9):1162-7. · 8.73 Impact Factor
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ABSTRACT: CD4(+) T cells producing IL-17 [T helper (Th)17], as distinct from Th1 or Th2 cells, have recently been shown to be associated with autoimmunity, but it is not entirely clear how Th17 cells are generated from naïve T cells. We demonstrate here that IL-6, but not TNF-alpha or IL-1beta, can, in combination with TGF-beta, induce Th17 cell generation from naïve T cells and inhibit TGF-beta-induced Foxp3 expression. Moreover, conditioned medium from lipopolysaccharide-stimulated bone marrow-derived dendritic cells (DCCM) can induce IL-17 production in naïve T cells. Interestingly, IL-17 was produced by DCCM even with the addition of anti-gp130 antibody or DCCM from IL-6 KO mice. The combination of IL-6 and TGF-beta could maintain activation of signal transducer and activator of transcription (Stat)3, but not of Stat1. IL-27 or IFN-gamma suppressed the induction of Th17 cells by TGF-beta plus IL-6 and maintained Stat1 activation under these conditions. In contrast, both Stat1 and Stat3 remained to be activated in naïve T cells cultured with DCCM. These findings represent a different basis for Th17 differentiation from naïve T cells.
Proceedings of the National Academy of Sciences 08/2007; 104(29):12099-104. · 9.68 Impact Factor
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Susetta Finotto,
Tatjana Eigenbrod,
Roman Karwot,
Ildiko Boross,
Aysefa Doganci,
Hiroaki Ito,
Norihiro Nishimoto,
Kazuyuki Yoshizaki, Tadamitsu Kishimoto,
Stefan Rose-John,
Peter R Galle,
Markus F Neurath
[show abstract]
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ABSTRACT: We previously reported high levels of the soluble form of the IL-6R (sIL-6R) in the airways of asthmatic subjects. Here, we analyzed the IL-6R effects on Th2 cell survival in the lung by locally antagonizing sIL-6R-mediated trans-signaling with a designer fusion protein (gp130-Fc) as well as IL-6R signaling with an antibody against the gp80 unit of the IL-6R (alphaIL-6R) in a murine model of asthma after ovalbumin peptide (OVA) sensitization and challenge. Blockade of the sIL-6R led to a significant decrease in inflammatory cells by an apoptosis-independent mechanism. In contrast, local treatment with alphaIL-6R antibodies that also block signaling via the membrane-bound IL-6R (mIL-6R) led to decreased signal transducers and activators of transcription (STAT)-3 but not STAT-1 phosphorylation in the lung of treated mice as compared with control-treated mice. Moreover, this treatment induced apoptosis of the cells present in the airways of OVA-treated mice as well as apoptosis of lung CD4+ effector T cells. Subsequent studies showed that this effect was mediated by lung CD4+CD25+Foxp3+ T regulatory cells by a cell-cell interaction, thereby contributing to the resolution of airway hyperresponsiveness in OVA-treated mice given anti-IL-6R antibodies. Taken together, these data suggest that blockade of mIL-6R signaling leads to cell death of lung effector T cells by activating regulatory T cells in experimental asthma. Local targeting of IL-6R signaling could be a novel approach for inducing Th2 T cell death in allergic airways via regulatory T cells.
International Immunology 07/2007; 19(6):685-93. · 3.41 Impact Factor
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Ryusuke Kimura,
Makiko Maeda,
Atsushi Arita,
Yuichi Oshima,
Masanori Obana,
Takashi Ito,
Yasuhiro Yamamoto,
Tomomi Mohri, Tadamitsu Kishimoto,
Ichiro Kawase,
Yasushi Fujio,
Junichi Azuma
[show abstract]
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ABSTRACT: Interleukin (IL)-6 family cytokines, which share glycoprotein 130 (gp130) as a signal-transducing receptor component, play important roles in the maintenance of cardiac homeostasis. IL-11, a member of IL-6 family cytokines, is expressed in cardiac myocytes, though it remains to be elucidated how IL-11 functions in the hearts. In the present study, first, we showed that IL-11 administration reduced the ischemia/reperfusion injury in the hearts. IL-11 receptor alpha was expressed in cardiomyocytes. IL-11 treatment rapidly activated signal transducer and activator of transcription 3 (STAT3) and extracellular signal-regulated kinase (ERK) 1/2 in cardiac myocytes. IL-11 stimulation resulted in the translocation of phosphorylated STAT3 into nuclei. Immunofluorescence microscopic analyses revealed that IL-11 treatment led to the cell elongation, as is the case with other cardiotrophic members of IL-6 family, such as leukemia inhibitory factor. Finally we showed that IL-11 treatment conferred the resistance to cell death induced by hydrogen peroxide, which was abrogated by adenoviral transfer of dominant negative STAT3, but not by the inhibition of ERK1/2 with U0126. These findings indicate that IL-11 mediates cytoprotective signals in cardiomyocytes, proposing that IL-11 has the potential to exhibit cardioprotection as a novel biological function.
Cytokine 06/2007; 38(2):107-15. · 3.02 Impact Factor
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ABSTRACT: Pioglitazone is widely used for the treatment of diabetic patients with insulin resistance. The mechanism of pioglitazone to improve insulin sensitivity is not fully understood. Recent studies have shown that the induction of suppressor of cytokine signaling 3 (SOCS3) is related to the development of insulin resistance. Here, we examined whether the insulin-sensitizing effect of pioglitazone affects the SOCS induction. In db/db mice and high-fat-fed mice, expression of SOCS3 mRNA in fat tissue was increased compared with that in lean control mice, and pioglitazone suppressed SOCS3 levels. In 3T3-L1 adipocytes, mediators of insulin resistance such as tumor necrosis factor-alpha (TNF-alpha), interleukin-6, growth hormone, and insulin increased SOCS3 expression, which was partially inhibited by pioglitazone. The ability of pioglitazone to suppress SOCS3 induction by TNF-alpha was greatly augmented by peroxisome proliferator-activated receptor gamma overexpression. SOCS3 overexpression and tyrphostin AG490, a Janus kinase 2 inhibitor, or dominant-negative STAT3 expression partially inhibited adiponectin secretion and was accompanied by decreased STAT3 phosphorylation. Conversely, pioglitazone increased adiponectin secretion and STAT3 phosphorylation in fat tissue of db/db mice and in 3T3-L1 adipocytes. These results suggest that pioglitazone exerts its effect to improve whole-body insulin sensitivity in part through the suppression of SOCS3, which is associated with the increase in STAT3 phosphorylation and adiponectin production in fat tissue.
Diabetes 04/2007; 56(3):795-803. · 8.29 Impact Factor
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ABSTRACT: Interleukin (IL)-6 is a pleiotropic cytokine that has important roles in the regulation of the immune response, inflammation, and hematopoiesis. Disruption of IL-6 regulation might, however, affect the immune response and consequently induce immune-mediated inflammatory diseases such as rheumatoid arthritis, systemic juvenile idiopathic arthritis, Castleman disease, and Crohn's disease. Overproduction of IL-6 also contributes, through its roles as a growth factor or an antiapoptotic factor, to the development of malignant diseases such as multiple myeloma and renal cancer. Progress in the study of IL-6 has increased our understanding of the pathological roles of this cytokine in these diseases and provided key evidence that antagonizing its activities can be used as a therapeutic strategy. The application of molecular biology techniques to design monoclonal antibodies as therapeutic agents has made it possible to regulate the IL-6 signal to successfully treat diseases that have so far proved refractory to conventional therapies. Blocking IL-6 actions by use of a humanized antibody, tocilizumab, which targets the IL-6 receptor, has been proven to be therapeutically effective for rheumatoid arthritis, systemic juvenile idiopathic arthritis, Castleman disease and Crohn's disease. In this review, we discuss a paradigm of IL-6 from basic science to clinical use.
Nature Clinical Practice Rheumatology 12/2006; 2(11):619-26. · 5.85 Impact Factor
