Sachie Kitano

Publications (8)17.29 Total impact

• Source

  Available from: Atsushi Satake

  Dataset: The Protective Role of Host Toll-Like Receptor-4 in aGVHD (Transplantation 2010)

  Takehito Imado, Tsuyoshi Iwasaki, Sachie Kitano, Atsushi Satake, Takanori Kuroiwa, Sachi Tsunemi, Hajime Sano
• Article: Effect of transient expression of fluorescent protein probes in synovial and myoblast cell lines.

  Seiji Shibasaki, Aika Fujita, Chihiro Usui, Sachiko Watanabe, Sachie Kitano, Hajime Sano, Tsuyoshi Iwasaki
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  ABSTRACT: Here, we investigate the appropriate fluorescent proteins for use in the culture of synovial MH7A and myoblast C2C12 cells. Fluorescent signal intensities of 3 different fluorescent proteins were examined in these cell lines. The fluorescent intensity of transiently expressed AcGFP, DsRed, and mStrawberry were examined in these cell lines, and the influence of the amount of plasmid used on transfection efficiency and cell viability were investigated.
  SpringerPlus. 12/2012; 1(1):36.
• Article: Sphingosine 1-phosphate receptor activation enhances BMP-2-induced osteoblast differentiation.

  Chieri Sato, Tsuyoshi Iwasaki, Sachie Kitano, Sachi Tsunemi, Hajime Sano
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  ABSTRACT: We previously demonstrated that sphingosine 1-phosphate (S1P) receptor-mediated signaling induced proliferation and prostaglandin productions by synovial cells from rheumatoid arthritis (RA) patients. In the present study we investigated the role of S1P receptor-mediated signaling for osteoblast differentiation. We investigated osteoblast differentiation using C2C12 myoblasts, a cell line derived from murine satellite cells. Osteoblast differentiation was induced by the treatment of bone morphogenic protein (BMP)-2 in the presence or absence of either S1P or FTY720 (FTY), a high-affinity agonist of S1P receptors. Osteoblast differentiation was determined by osteoblast-specific transcription factor, Runx2 mRNA expression, alkaline phosphatase (ALP) activity and osteocalcin production by the cells. Smad1/5/8 and extracellular signal-regulated kinase (ERK) 1/2 phosphorylation was examined by Western blotting. Osteocalcin production by C2C12 cells were determined by ELISA. Runx2 expression and ALP activity by BMP-2-stimulated C2C12 cells were enhanced by addition of either S1P or FTY. Both S1P and FTY enhanced BMP-2-induced ERK1/2 and Smad1/5/8 phosphorylation. The effect of FTY was stronger than that of S1P. S1P receptor-mediated signaling on osteoblast differentiation was inhibited by addition of mitogen-activated protein kinase/ERK kinase (MEK) 1/2 inhibitor, indicating that the S1P receptor-mediated MEK1/2-ERK1/2 signaling pathway enhanced BMP-2-Smad signaling. These results indicate that S1P receptor-mediated signaling plays a crucial role for osteoblast differentiation.
  Biochemical and Biophysical Research Communications 05/2012; 423(1):200-5. · 2.48 Impact Factor
• Article: Sphingosine 1-phosphate (S1P)/S1P receptor 1 signaling regulates receptor activator of NF-κB ligand (RANKL) expression in rheumatoid arthritis.

  Harunori Takeshita, Masayasu Kitano, Tsuyoshi Iwasaki, Sachie Kitano, Sachi Tsunemi, Chieri Sato, Masahiro Sekiguchi, Naoto Azuma, Keiji Miyazawa, Timothy Hla, Hajime Sano
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  ABSTRACT: Sphingosine 1-phosphate (S1P)/S1P receptor 1 (S1P1) signaling plays an important role in synovial cell proliferation and inflammatory gene expression by rheumatoid arthritis (RA) synoviocytes. The purpose of this study is to clarify the role of S1P/S1P1 signaling in the expression of receptor activator of NF-κB ligand (RANKL) in RA synoviocytes and CD4(+) T cells. We demonstrated MH7A cells, a human RA synovial cell line, and CD4(+) T cells expressed S1P1 and RANKL. Surprisingly, S1P increased RANKL expression in MH7A cells and CD4(+) T cells in a dose-dependent manner. Moreover, S1P enhanced RANKL expression induced by stimulation with TNF-α in MH7A cells and CD4(+) T cells. These effects of S1P in MH7A cells were inhibited by pretreatment with PTX, a specific Gi/Go inhibitor. These findings suggest that S1P/S1P1 signaling may play an important role in RANKL expression by MH7A cells and CD4(+) T cells. S1P/S1P1 signaling of RA synoviocytes is closely connected with synovial hyperplasia, inflammation, and RANKL-induced osteoclastogenesis in RA. Thus, regulation of S1P/S1P1 signaling may become a novel therapeutic target for RA.
  Biochemical and Biophysical Research Communications 02/2012; 419(2):154-9. · 2.48 Impact Factor
• Source

  Available from: Tsuyoshi Iwasaki

  Article: Therapy of autoimmune diseases by novel immunosuppressant FTY720

  Sachi Tsunemi, Tsuyoshi Iwasaki, Keiji Miyazawa, Sachie Kitano, Chieri Kanda, Harunori Takeshita, Masahiro Sekiguchi, Masayasu Kitano, Hajime Sano
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  ABSTRACT: FTY720 (FTY) is a new immunosuppressant which modulates sphingosine 1-phospate re-ceptors. FTY has been shown to be highly effective to multiple sclerosis in clinical studies. Recently, we reported the effects and the mechanisms by which FTY inhibited arthritis in rheumatoid arthritis model of SKG mice. Here, we briefly review up to date reports of FTY including our experimental results.
  Inflammation and Regeneration 04/2011; 31.
• Source

  Available from: Atsushi Satake

  Article: The protective role of host Toll-like receptor-4 in acute graft-versus-host disease.

  Takehito Imado, Tsuyoshi Iwasaki, Sachie Kitano, Atsushi Satake, Takanori Kuroiwa, Sachi Tsunemi, Hajime Sano
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  ABSTRACT: Mutations in Toll-like receptor (TLR)-4 have been associated with the hyporesponsiveness of macrophages to lipopolysaccharide, possibly reducing the risk of acute graft-versus-host disease (GVHD). However, TLR-4 mutations may also increase the risk of intestinal damage and microbial infection, thereby accelerating acute GVHD. In this study, we investigated the role of TLR-4 in triggering acute GVHD using C3H/HeJ mice with disrupted TLR-4 and C3H/HeN mice with intact TLR-4 as recipients in an acute GVHD model. TLR-4 expression was significantly increased in the intestines and livers from acute GVHD mice. TLR-4-mutant C3H/HeJ hosts that received C57BL/6 (B6) donor cells developed significantly more severe GVHD than TLR-4-intact C3H/HeN hosts receiving B6 donor cells. Antibiotic treatment prolonged the survival of C3H/HeN-host GVHD mice but reduced the survival of C3H/HeJ-host GVHD mice. C3H/HeJ-host GVHD mice showed increased lipopolysaccharide levels in the blood, donor cell and CD68+ cell infiltration, tumor necrosis factor-α mRNA expression, and more apoptotic cells in the intestine compared with C3H/HeN host GVHD mice. In contrast, intestinal cyclooxygenase-2, prostaglandin E2, and hepatocyte growth factor expression in C3H/HeJ-host GVHD mice were significantly decreased compared with C3H/HeN-host GVHD mice. Our results indicated that host TLR-4 is crucial for the induction of tissue protective factors and for protection against intestinal cell apoptosis during acute GVHD.
  Transplantation 10/2010; 90(10):1063-70. · 4.00 Impact Factor
• Article: Effects of the novel immunosuppressant FTY720 in a murine rheumatoid arthritis model.

  Sachi Tsunemi, Tsuyoshi Iwasaki, Sachie Kitano, Takehito Imado, Keiji Miyazawa, Hajime Sano
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  ABSTRACT: We investigated the effects and mechanisms by which FTY720 (FTY) inhibits arthritis development in the SKG mouse rheumatoid arthritis (RA) model. FTY (1mg/kg/day) administration suppressed the progression of laminarin-induced arthritis in SKG mice. FTY treatment decreased IL-6 and TNF-alpha expression in synovial fibroblast cells and the number of inflammatory cells overall. Bone destruction was also suppressed by treatment with FTY. The numbers of CD4(+) and CD8(+) T cells were significantly increased in the thymus and decreased in the spleen in FTY-treated SKG mice. FTY enhanced IL-4 production by CD4(+) T cells stimulated by allogeneic spleen cells and inhibited prostaglandin E(2) (PGE(2)) production by a TNF-alpha-stimulated synovial fibroblast cell line. These results indicate that FTY can inhibit arthritis in SKG mice via sequestration of autoimmune CD4(+) T cells in the thymus, enhancement of Th2 immune responses, and inhibition of PGE(2) production by synovial cells.
  Clinical Immunology 08/2010; 136(2):197-204. · 4.05 Impact Factor
• Source

  Available from: Tsuyoshi Iwasaki

  Article: Hepatocyte growth factor ameliorates dermal sclerosis in the tight-skin mouse model of scleroderma.

  Tsuyoshi Iwasaki, Takehito Imado, Sachie Kitano, Hajime Sano
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  ABSTRACT: The tight-skin (TSK/+) mouse, a genetic model of systemic sclerosis (SSc), develops cutaneous fibrosis and defects in pulmonary architecture. Because hepatocyte growth factor (HGF) is an important mitogen and morphogen that contributes to the repair process after tissue injury, we investigated the role of HGF in cutaneous fibrosis and pulmonary architecture defects in SSc using TSK/+ mice. TSK/+ mice were injected in the gluteal muscle with either hemagglutinating virus of Japan (HVJ) liposomes containing 8 mug of a human HGF expression vector (HGF-HVJ liposomes) or a mock vector (untreated control). Gene transfer was repeated once weekly for 8 weeks. The effects of HGF gene transfection on the histopathology and expression of tumor growth factor (TGF)-beta and IL-4 mRNA in TSK/+ mice were examined. The effect of recombinant HGF on IL-4 production by TSK/+ CD4+ T cells stimulated by allogeneic dendritic cells (DCs) in vitro was also examined. Histologic analysis revealed that HGF gene transfection in TSK/+ mice resulted in a marked reduction of hypodermal thickness, including the subcutaneous connective tissue layer. The hypodermal thickness of HGF-treated TSK/+ mice was decreased two-fold to three-fold compared with untreated TSK/+ mice. However, TSK/+ associated defects in pulmonary architecture were unaffected by HGF gene transfection. HGF gene transfection significantly inhibited the expression of IL-4 and TGF-beta1 mRNA in the spleen and skin but not in the lung. We also performed a mixed lymphocyte culture and examined the effect of recombinant HGF on the generation of IL-4. Recombinant HGF significantly inhibited IL-4 production in TSK/+ CD4+ T cells stimulated by allogeneic DCs. HGF gene transfection inhibited IL-4 and TGF-beta mRNA expression, which has been postulated to have a major role in fibrinogenesis and reduced hypodermal thickness, including the subcutaneous connective tissue layer of TSK/+ mice. HGF might represent a novel strategy for the treatment of SSc.
  Arthritis research & therapy 02/2006; 8(6):R161. · 4.27 Impact Factor