Kensuke Koyama

University of Yamanashi, Kōhu, Yamanashi, Japan

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Publications (14)56.27 Total impact

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    ABSTRACT: Thymic stromal lymphopoietin (TSLP) has been recently suggested to play an important role in the pathophysiology of rheumatoid arthritis (RA). However, there is little information on serum TSLP concentrations in RA and its clinical significance. The present study investigated whether serum TSLP concentrations were affected in patients with RA. Using an enzyme-linked immunosorbent assay (ELISA), we measured TSLP concentrations in the serum obtained from 100 patients with RA, 60 patients with osteoarthritis (OA), and 34 healthy volunteers. We also investigated the correlation between serum TSLP concentrations and clinical parameter of disease activity in RA (Disease activity score using 28 joint counts [DAS28]-C-reactive protein [CRP], DAS28-erythrocyte sedimentation rate [ESR], Clinical Disease Activity Index [CDAI], patient's/-physician's Visual Analog Scale [VAS], swollen joints count, tender joints count, CRP, ESR, and matrix metalloproteinase-3 [MMP-3] concentrations) . In addition, we investigated the correlation between serum TSLP concentrations and anti-citrullinated peptide antibody [ACPA] and serum tumor necrosis factor (TNF)-α. Serum TSLP levels in patients with RA were significantly higher than those in patients with OA and in healthy volunteers. Interestingly, serum TSLP concentrations were significantly correlated with ACPA titers, but not with other clinical parameters. There was a significant increase in serum TSLP concentrations in patients with RA, which was positively correlated with serum ACPA titers. These findings suggest that in patients with RA, TSLP may play a role in ACPA production by B-cells. This article is protected by copyright. All rights reserved. © 2015 British Society for Immunology.
    Clinical & Experimental Immunology 03/2015; DOI:10.1111/cei.12632 · 3.28 Impact Factor
  • K. Koyama, K. Matsuda, H. Haro
    Annals of the Rheumatic Diseases 06/2014; 73(Suppl 2):827-827. DOI:10.1136/annrheumdis-2014-eular.2017 · 9.27 Impact Factor
  • K. Koyama, T. Ohba, H. Sato, H. Haro
    03/2014; 2(1):e3-e3. DOI:10.2106/JBJS.CC.K.00049
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    ABSTRACT: Thymic stromal lymphopoietin (TSLP), an IL-7-like cytokine, is highly expressed in herniated disc (HD) tissue and may act as a key molecule for the initiation of macrophage recruitment into the tissue and natural resorption of HD. However, it remains unclear how TSLP expression is regulated in the intervertebral discs. This study showed that expression of TSLP and phosphorylated NF-κB in HD tissue samples was inversely correlated with expression of phosphorylated Smad2/3 (an indicator of active TGF-β signaling) and vice versa in posterior lumbar spinal fusion samples. The pharmacological blockades of endogenous TGF-β activity induced TSLP expression in mouse intervertebral disc tissue culture, which was inhibited by NF-κB inhibitors. Additionally, phosphorylation of Smad2/3 was constitutively detected in mouse intervertebral disc tissue in the steady states. Collectively, these results suggest that endogenous TGF-β activity limits TSLP expression in intervertebral disc tissue in the steady states by suppressing NF-κB activation. The findings reveal a regulatory mechanism how TSLP expression is induced in the intervertebral disc tissue and suggest a novel role of TGF-β in maintaining the homeostasis of intervertebral disc tissue. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.
    Journal of Orthopaedic Research 07/2013; 31(7). DOI:10.1002/jor.22337 · 2.97 Impact Factor
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    ABSTRACT: Subtilase cytotoxin (SubAB) is the prototype of a newly identified family of AB(5) cytotoxins produced by Shiga toxigenic Escherichia coli. SubAB specifically cleaves the essential endoplasmic reticulum (ER) chaperone BiP (GRP78), resulting in the activation of ER stress-induced unfolded protein response (UPR). We have recently shown that the UPR following ER stress can suppress cellular responses to inflammatory stimuli during the later phase, in association with inhibition of NF-kappaB activation. These findings prompted us to hypothesize that SubAB, as a selective UPR inducer, might have beneficial effects on inflammation-associated pathology via a UPR-dependent inhibition of NF-kappaB activation. The pretreatment of a mouse macrophage cell line, RAW264.7, with a subcytotoxic dose of SubAB-triggered UPR and inhibited LPS-induced MCP-1 and TNF-alpha production associated with inhibition of NF-kappaB activation. SubA(A272)B, a SubAB active site mutant that cannot induce UPR, did not show such effects. In addition, pretreatment with a sublethal dose of SubAB, but not SubA(A272)B, protected the mice from LPS-induced endotoxic lethality associated with reduced serum MCP-1 and TNF-alpha levels and also prevented the development of experimental arthritis induced by LPS in mice. Collectively, although SubAB has been identified originally as a toxin associated with the pathogenesis of hemolytic uremic syndrome, the unique ability of SubAB to selectively induce the UPR may have the potential to prevent LPS-associated inflammatory pathology under subcytotoxic conditions.
    The Journal of Immunology 07/2009; 183(2):1368-74. DOI:10.4049/jimmunol.0804066 · 5.36 Impact Factor
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    ABSTRACT: We previously demonstrated that VEGF and its receptors were expressed in human herniated discs (HD). TNF-alpha induced VEGF, resulting in neovascularization of disc tissues in a model of HD. The goal of the current research was to investigate the precise role of TNF-alpha-induced VEGF and the mechanism of angiogenesis in disc tissues. We performed ELISAs, Western blots, and immunohistological examinations to assess the role of TNF-alpha-induced VEGF using organ disc cultures with wild type, TNF receptor 1-null (TNF-RI(null)), or TNF receptor 2-null (TNF-RII(null)) mice. VEGF induction was inhibited when we used TNF-RI(null)-derived disc tissues. NF-kappaB pathway inhibitors also strongly suppressed VEGF induction. Thus, TNF-alpha induced VEGF expression in disc cells primarily through the NF-kappaB pathway. In addition, VEGF immunoreactivity was detected predominantly in annulus fibrosus cells and increased after TNF-alpha stimulation. TNF-alpha treatment also resulted in CD31 expression on endothelial cells and formation of an anastomosing network. In contrast, angiogenic activity was strongly inhibited in the presence of NF-kappaB inhibitors or anti-VEGF antibody. Our data show angiogenesis activity in disc tissues is regulated by VEGF and the NF-kappaB pathway, both of which are induced by TNF-alpha. The level of angiogenic activity in disc tissues was closely related to aging. Because neovascularization of HD is indispensable for HD resorption, the prognosis of HD and the rate of the resorption process in patients may vary as a function of the patient's age.
    Journal of Orthopaedic Research 02/2009; 27(2):229-35. DOI:10.1002/jor.20727 · 2.97 Impact Factor
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    ABSTRACT: Fatigue fractures frequently involve the tibia metatarsal bones in adolescents. In the diagnosis of fatigue fracture, medical history, physical examination, and plain radiographs are important but are limited for early and precise diagnosis, because fatigue fractures sometimes reveal no gait disturbance, slight limitation of hip motion, and normal plain radiographs. This article presents a rare case of fatigue fracture in the bilateral femoral neck of a 61-year-old woman. She had no history of trauma or disease. Although she had pain and limitation of movement in the hip, she was able to ambulate and continue to work. Plain radiographs and magnetic resonance imaging (MRI) showed fracture of the bilateral femoral neck without displacement. Bone mineral density of the lumbar spine was 0.82 g/cm2, which ruled out osteoporosis. Based on this, we diagnosed fatigue fracture. Regardless of nondisplacement type, we treat operatively. Two months postoperatively she returned to work, and 4 months postoperatively she recovered completely. Plain radiographs showed evidence of callus formation. This case indicates that fatigue fracture can occur in the elderly. Choice of treatment should be decided not only by plain radiographs but also by the condition of the individual patient. We suggest that an undisplaced femoral neck fatigue fracture be treated conservatively in principle, but recommend that operative treatment be considered in bilateral cases in the elderly and those noncooperative for bed rest. There is no doubt that MRI is the most useful method for early diagnosis of a femoral neck fatigue fracture. Early diagnosis by MRI and choice of treatment by plain radiograph will lead to a good prognosis.
    Orthopedics 12/2008; 31(11):1141. DOI:10.3928/01477447-20081101-09 · 0.98 Impact Factor
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    ABSTRACT: To determine whether thymic stromal lymphopoietin (TSLP) plays a role in the resorption of herniated disc tissue. The expression of TSLP messenger RNA (mRNA) and protein in mouse intervertebral disc cells was assessed by quantitative real-time polymerase chain reaction, enzyme-linked immunosorbent assay (ELISA), and immunohistochemical analysis. The ability of mouse intervertebral disc cells to respond to TSLP stimulation was examined by Western blot analysis, ELISA, and protein array analysis. Intracellular signaling pathways involved in TSLP signaling in mouse intervertebral disc cells were investigated using several chemical inhibitors. The role of TSLP in macrophage migration into the intervertebral disc was assessed by in vitro migration assay. Finally, TSLP expression in clinical specimens derived from patients with a herniated disc was examined by immunohistochemistry. Mouse intervertebral disc cells expressed TSLP mRNA and protein upon stimulation with NF-kappaB-activating ligands such as tumor necrosis factor alpha. In addition, the mouse intervertebral disc cells expressed the TSLP receptor and produced monocyte chemotactic protein 1 (MCP-1; CCL2) and macrophage colony-stimulating factor in response to TSLP stimulation. Both anulus fibrosus and nucleus pulposus intervertebral disc cells expressed MCP-1 upon TSLP stimulation, which was mediated via the phosphatidylinositol 3-kinase/Akt pathway. Consistently, the supernatants of TSLP-activated intervertebral disc cultures had the capacity to induce macrophage migration in an MCP-1-dependent manner. Finally, TSLP and MCP-1 were coexpressed in human herniated disc specimens in which macrophage infiltration into the tissue was observed. TSLP induced by NF-kappaB-activating ligands in intervertebral discs may contribute to the recruitment of macrophages to the intervertebral disc by stimulating MCP-1 production and may be involved in the resorption of herniated disc tissue.
    Arthritis & Rheumatology 11/2008; 58(11):3510-9. DOI:10.1002/art.23965 · 7.87 Impact Factor
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    ABSTRACT: Molecular biologic and immuno-histologic analyses using in vitro murine intervertebral disc tissue culture. To investigate the role of tumor necrosis factor-like weak inducer of apoptosis (TWEAK) in matrix metalloproteinase 3 (MMP-3) pathway induction, and the effect of TWEAK to induce other cytokines or angiogenesis factors in disc tissues. We previously demonstrated that TWEAK and its receptor Fn14 were expressed in murine disc tissues. TWEAK induced MMP-3 upregulation and aggrecan downregulation in disc tissues. Enzyme-Linked ImmunoSorbent Assay (ELISA), western blot, and immuno-histologic analyses were used to assess the role of TWEAK-induced MMP-3, using murine disc tissue culture. TWEAK induced disc cells to generate MMP-3 as did TNF-alpha and IL-1beta. MMP-3 activity was detectable in murine disc cells. MMP-3 induction was markedly inhibited with a c-Jun N-terminal kinase (JNK) inhibitor. Phosphorylation of JNK was also confirmed. Introduction of TWEAK resulted in the degradation of disc matrix in organ disc culture, whereas proteoglycan degradation was markedly abrogated in the presence of an MMP-3 specific inhibitor or a JNK inhibitor. In addition, TWEAK also induced monocyte chemotactic protein (MCP)-1 via the NF-kappaB pathway, as phosphorylation of NF-kappaB was confirmed by western blotting. TWEAK plays an important role in MMP-3 induction in murine disc cells via JNK that results in degradation of disc matrix. TWEAK also induces MCP-1, which belongs to the chemokine family that recruits inflammatory cells via the NF-kappaB pathway.
    Spine 11/2008; 33(23):2489-94. DOI:10.1097/BRS.0b013e318186b343 · 2.45 Impact Factor
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    ABSTRACT: Epidemiologic studies suggest that TGF-beta in breast milk provides protection against allergic disease during infancy. However, it is unclear whether orally administered TGF-beta, such as TGF-beta in human milk, retains and exerts its activity in the intestinal mucosa and can affect immune response (tolerance) to dietary antigens. We sought to determine whether orally administered TGF-beta is biologically active in intestinal mucosa and affects oral tolerance. Activity of orally administered TGF-beta in the intestinal mucosa was evaluated by means of in vivo imaging with transgenic mice expressing a Smad-responsive reporter construct (SBE-luc mice), by means of immunohistochemical staining with anti-phosphorylated Smad2 antibody, and by means of real-time RT-PCR analysis of TGF-beta and Smad7 mRNA expression. The effects of orally administered TGF-beta on oral tolerance induction were assessed in mice tolerized by means of high-dose ovalbumin (OVA) feeding. The oral administration of TGF-beta increased Smad-responsive reporter activity in the intestines of SBE-luc mice and induced Smad2 phosphorylation and TGF-beta and Smad7 mRNA expression in the intestines of BALB/c mice. Serum TGF-beta levels were also increased after oral administration of TGF-beta. BALB/c mice treated orally with OVA and TGF-beta showed augmented reduction of OVA-specific IgE and IgG1 antibodies, T-cell reactivity, and immediate-type skin reactions when compared with the mice treated orally with OVA alone. Orally administered TGF-beta retains sufficient biologic activity in intestinal mucosa and enhances oral tolerance. Oral administration of TGF-beta might become a potential strategy to prevent allergic diseases, such as food allergy.
    Journal of Allergy and Clinical Immunology 11/2007; 120(4):916-23. DOI:10.1016/j.jaci.2007.05.023 · 11.25 Impact Factor
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    ABSTRACT: Thymic stromal lymphopoietin (TSLP) is an IL-7-like cytokine that triggers dendritic cell-mediated Th2-type inflammatory responses and is considered as a master switch for allergic inflammation. In this study, we found increased levels of TSLP and, also TNF-alpha as previously reported, in synovial fluid specimens derived from patients with rheumatoid arthritis (RA) when compared with those from patients with osteoarthritis (OA). In addition, TNF-alpha up-regulated TSLP expression in RA- and OA-derived synovial fibroblasts, which was inhibited by IFN-gamma. Furthermore, anti-TSLP neutralizing antibody ameliorated a TNF-alpha-dependent experimental arthritis induced by anti-type II collagen antibody in mice. Collectively, these results suggest that TSLP, as a downstream molecule of TNF-alpha, may be involved in the pathophysiology of inflammatory arthritis. TSLP might thus play a role not only in allergic diseases but also in inflammatory arthritis such as RA.
    Biochemical and Biophysical Research Communications 06/2007; 357(1):99-104. DOI:10.1016/j.bbrc.2007.03.081 · 2.28 Impact Factor
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    ABSTRACT: Rheumatoid arthritis (RA) is characterized by hypertrophic synovial tissues comprising excessively proliferating synovial fibroblasts and infiltrating inflammatory cells. Transforming growth factor-beta (TGF-beta) is a multifunctional cytokine that regulates cell growth, inflammation and angiogenesis by acting on various cell types. In RA synovial tissues, TGF-beta is expressed at high levels. However, the precise role of TGF-beta in RA remains unclear. We herein demonstrated a causal link between the TGF-beta-induced RA synovial cell proliferation and induction of platelet-derived growth factor (PDGF)-AA. In addition, TGF-beta induced IL-6 and vascular endothelial growth factor (VEGF) production by RA synovial fibroblasts associated with nuclear factor-kappa B activation. These effects of TGF-beta on RA synovial fibroblasts were suppressed by TGF-beta type I receptor kinase inhibitor HTS466284. Furthermore, HTS466284 significantly prevented anti-collagen type II antibody-induced arthritis in mice according to the clinical manifestations, histology, tumor necrosis factor-alpha, PDGF and VEGF expression and 5-bromo-2'-deoxyuridine incorporation. These in vitro and in vivo results suggest that TGF-beta plays a role in the development of synovial hyperplasia consisting of synovial cell proliferation, inflammation and angiogenesis. The blockade of TGF-beta signaling may thus become an additional strategy for the treatment of RA.
    International Immunology 03/2007; 19(2):117-26. DOI:10.1093/intimm/dxl128 · 3.18 Impact Factor
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    ABSTRACT: Rheumatoid arthritis (RA) is a chronic inflammatory disease that is associated with joint destruction. Imatinib mesylate (imatinib) is an inhibitor that specifically targets a set of protein tyrosine kinase, such as abl, c-kit, and platelet-derived growth factor receptor (PDGFR) and it is widely used to treat chronic myeloid leukemia (CML). The purpose of the present study is to determine whether imatinib can provide benefit in the arthritis induced by anti-collagen type II antibody (CAIA) in mice, a model that provides an opportunity to study the effector inflammatory phase of arthritis without involving the priming phase of the immune responses. Mice treated with intraperitoneal administration of imatinib (1 or 10 mg/kg) prior to the development of CAIA displayed significant reductions in the severity of CAIA as assessed by arthritis score, histology, and synovial PDGF and vascular endothelial growth factor expression. In addition, treatment of the mice that had developed CAIA with intraperitoneal administration of imatinib (1 or 10 mg/kg) inhibited the progression of arthritis as assessed by those parameters. These results suggest that imatinib prevents and treats CAIA. Imatinib may thus have both a preventive and therapeutic potential for the joint inflammation at the effector stage of RA.
    Modern Rheumatology 02/2007; 17(4):306-10. DOI:10.1007/s10165-007-0592-9 · 2.21 Impact Factor
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    ABSTRACT: Thymic stromal lymphopoietin (TSLP) is an interleukin (IL)-7-like cytokine produced by epithelial cells and triggers dendritic cell-mediated Th2 type allergic inflammatory responses. This study investigated whether Toll-like receptor (TLR) ligands, lipopolysaccharide (LPS) and poly-IC affect TSLP production in synovial fibroblasts. Enzyme-linked immunosorbent assay showed that LPS and poly-IC upregulated TSLP production in synovial fibroblasts obtained from patients with rheumatoid arthritis (RA) and osteoarthritis (OA). In addition, we found that nuclear factor (NF)-kappaB inhibitor IMD-0354, dexamethasone, and interferon (IFN)-gamma inhibited the LPS- and poly-IC-induced TSLP production in RA and OA synovial fibroblasts. Thus, LPS and poly-IC can upregulate TSLP via a NF-kappaB pathway in synovial fibroblasts, which is downregulated by dexamethasone and interferon (IFN)-gamma. The current findings suggest that TSLP may be involved in the pathophysiology of inflammatory arthritis as well as allergic disease.
    Modern Rheumatology 02/2007; 17(6):459-63. DOI:10.1007/s10165-007-0620-9 · 2.21 Impact Factor