R Murayama

Publications (2)2.65 Total impact

• Article: MAPKs, activator protein-1 and nuclear factor-κB mediate production of interleukin-1β-stimulated cytokines, prostaglandin E₂ and MMP-1 in human periodontal ligament cells.

  R Murayama, M Kobayashi, A Takeshita, T Yasui, M Yamamoto
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  ABSTRACT: Determination of the interleukin-1 (IL-1) signaling cascades that lead to the production of various inflammatory mediators and catabolic factors may clarify attractive targets for therapeutic intervention for periodontitis. We comprehensively assessed the involvement of MAPKs, activator protein-1 (AP-1) and nuclear factor-κB (NF-κB) in IL-1β-induced production of interleukin-6 (IL-6), interleukin-8 (IL-8), prostaglandin E(2) (PGE(2) ) and MMP-1 in human periodontal ligament cells. Human periodontal ligament cells were pretreated with an inhibitor for each of the MAPKs or NF-κB and subsequently treated with IL-1β. Following treatment, phosphorylation of three types of MAPK (ERK, p38 MAPK and c-Jun N-terminal kinase), IκB kinase (IKK) α/β/γ and IκB-α, as well as the DNA binding activity of AP-1 and NF-κB and the production of IL-6, IL-8, PGE(2) and MMP-1, were determined by western blotting, a gel mobility shift assay and ELISA, respectively. The three MAPKs, simultaneously activated by IL-1β, mediated the subsequent DNA binding of AP-1 at various magnitudes, while IKKα/β/γ, IκB-α and NF-κB were also involved in the IL-1 signaling cascade. Furthermore, IL-1β stimulated the production of IL-6, IL-8, PGE(2) and MMP-1 via activation of the three MAPKs and NF-κB, because inhibitors of these significantly suppressed the IL-1β-stimulated production of these factors. Our results strongly suggest that MAPK, AP-1 and NF-κB mediate the IL-1β-stimulated synthesis of IL-6, IL-8, PGE(2) and MMP-1 in human periodontal ligament cells. Therefore, inhibition of activation of MAPK, AP-1 and/or NF-κB may lead to therapeutic effects on progression of periodontitis.
  Journal of Periodontal Research 05/2011; 46(5):568-75. · 1.69 Impact Factor
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  Available from: biosciencetrends.com

  Article: Association between the serum folate levels and tea consumption during pregnancy.

  Mie Shiraishi, Megumi Haruna, Masayo Matsuzaki, Erika Ota, Ryoko Murayama, Sachiyo Murashima
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  ABSTRACT: Folate is a vital nutrient during pregnancy for the prevention of neural tube defects, intrauterine fetal growth restriction and preeclampsia. Circulating folate levels might be negatively affected by ()-epigallocatechin gallate, which is a tea catechin found in green tea and oolong tea. The aim of this study was to determine whether consumption of green tea or oolong tea was associated with circulating folate levels among pregnant women in Japan. Two hundred and fifty-four healthy women with a singleton pregnancy (age: 30.4 ± 4.7, gestational age: 27.5 ± 9.6 weeks) were recruited from a prenatal clinic in metropolitan Tokyo, Japan. The serum folate levels were measured. Nutrient intake was assessed using a self-administered diet history questionnaire. Information on lifestyle variables was obtained from the questionnaire. The high consumption of green tea or oolong tea was defined as consumption more than 57.3 mL per 1,000 kcal, which is the 75th percentile of participants. The serum folate levels of the participants with high consumption of green tea or oolong tea was significantly lower than those of others (p = 0.027). A multiple regression analysis revealed the high consumption of green tea or oolong tea to be associated with a low serum folate level during pregnancy, after adjusting for confounding variables including dietary folate intake and use of folic acid supplements or multivitamins (β = -0.131, p = 0.016). The association between folate and the consumption of green tea or oolong tea may be useful to clarify the mechanism which links adverse perinatal outcomes and tea consumption.
  Bioscience trends 10/2010; 4(5):225-30. · 0.97 Impact Factor