Ikeda, Yumi



School of Medicine, Department of Internal Medicine (Rheumatology) (Shinanomachi)


Researcher (Non-tenured) / Project Researcher(Non-tenured)

Academic Background 【 Display / hide

  • 2013.04

    Osaka University, 薬学研究科

    Graduate School, Completed, Master's course


Research Areas 【 Display / hide

  • Life Science / Molecular biology

  • Life Science / Immunology


Papers 【 Display / hide

  • Elevated expression of BAFF receptor, BR3, on monocytes correlates with B cell activation and clinical features of patients with primary Sjögren's syndrome

    Yoshimoto K., Suzuki K., Takei E., Ikeda Y., Takeuchi T.

    Arthritis Research and Therapy (Arthritis Research and Therapy)  22 ( 1 )  2020.06

    ISSN  14786354

     View Summary

    Background: We reported that the production of BAFF (B cell-activating factor) and IL-6, both of which are involved in survival and differentiation of B cells, is dysregulated in monocytes of patients with primary Sjögren's syndrome (pSS). In this study, we investigate the relationship between possible aberrations of pSS monocytes and clinical features of pSS patients and the contribution of monocytes to B cell activation, a mechanism involved in the pathogenesis of pSS. Methods: Expression of BAFF-receptor (BR3) on peripheral monocytes from patients with pSS (n = 67) and healthy controls (HC: n = 37) was analyzed by FACS. Peripheral monocytes were stimulated with BAFF, and IL-6 production by the cells was measured by ELISA. Peripheral B cells were cultured with BAFF-stimulated monocytes in the presence or absence of anti-IL-6 receptor antibody, and IgG production by the cells was measured by ELISA. Patients' serological data were collected from their clinical records. Patients' disease activity was quantified based on their EULAR Sjögren's syndrome disease activity index (ESSDAI) scores. Results: The proportion of peripheral BR3-positive monocytes (BR3+/CD14+) was significantly increased in pSS patients compared to HC. Moreover, IL-6 production by BAFF-stimulated monocytes was remarkably higher than HC and was significantly correlated with BR3+/CD14+ ratios of patients. In addition, BR3 expression on pSS monocytes was elevated in anti-Ro/SSA and/or anti-La/SSB positive compared to negative patients. Remarkably, BR3 expression on peripheral monocytes was positively and significantly correlated with patients' serum IgG and IgM levels and ESSDAI scores. Moreover, the amount of IgG produced by B cells was markedly higher in pSS patients compared to HC when the cells were co-cultured with BAFF-stimulated autologous monocytes in vitro. Notably, addition of anti-IL-6 receptor antibody into the co-culture system led to inhibition of IgG production by B cells. Conclusions: Our data suggest that elevated BR3 expression in monocytes is associated with clinical features in pSS patients and that enhanced production of IL-6 by BAFF-stimulated monocytes plays a part in the overproduction of IgG by B cells in pSS. These results suggest that BAFF signaling pathways through BR3 in monocytes are possible therapeutic targets for pSS.

  • The role of galanin in the differentiation of mucosal mast cells in mice.

    Yamaguchi T., Ikeda Y., Tashiro K., Ohkawa Y., Kawabata K.

    European journal of immunology (Wiley-VCH GmbH, Weinheim)  50 ( 1 ) 110 - 118 2020.01

    Research paper (scientific journal), Joint Work, Accepted

     View Summary

    Mast cells are generally classified into two phenotypically distinct populations: mucosal-type mast cells (MMCs) and connective tissue-type mast cells (CTMCs). However, the molecular basis determining the different characteristics of the mast cell subclasses still remains unclear. Unfortunately, the number of mast cells that can be obtained from tissues is limited, which makes it difficult to study the function of each mast cell subclass. Here, we report the generation and characterization of MMCs and CTMCs derived from mouse BM mast cells (BMMCs). We found that the expression of galanin receptor 3 was elevated in MMCs when compared to the expression in CTMCs. Moreover, intraperitoneal injection of a galanin antagonist reduced MMCs and inhibited the inflammation of dextran sodium sulfate-induced colitis in mice. Therefore, these results suggest that galanin promotes MMC differentiation in vivo, and provide important insights into the molecular mechanisms underlying the differentiation of mast cell subclasses.

Presentations 【 Display / hide

  • 原発性シェーグレン症候群患者末梢血単球でのBAFF受容体発現亢進にはTLR4シグナル経路が関与する

    池田 由美



    Oral presentation (general)

  • Activation of signaling pathways of Toll-like receptor 4 promotes expression of BAFF receptor, BR3 in CD14+CD16+ human monocytes.

    Yumi Ikeda

    The 23nd Asia Pacific League of Associations for Rheumatology Congress, 


    Oral presentation (general)

  • 原発性シェーグレン症候群患者末梢血単球ではTLR4シグナル経路の活性化がBAFF受容体発現亢進に寄与する

    池田 由美



    Symposium, workshop panel (public)

  • Signaling pathways via Toll-like receptor 4 are involved in elevated expression of BAFF receptor in monocytes.

    Yumi Ikeda

    The 22nd Asia Pacific League of Associations for Rheumatology Congress, 


    Poster presentation

  • 原発性シェーグレン症候群患者末梢血単球でのBAFF受容体発現機構におけるToll様受容体の関与

    池田 由美

    第41回日本炎症・再生医学会 , 


    Poster presentation

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Research Projects of Competitive Funds, etc. 【 Display / hide

  • Elucidation of molecular mechanisms of monocyte activation through TLR signaling in Sjögrens syndrome.


    MEXT,JSPS, Grant-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Principal investigator

Awards 【 Display / hide

  • 優秀演題賞

    池田 由美, 2020.08, 日本炎症・再生医学会, 原発性シェーグレン症候群患者末梢血単球でのBAFF受容体発現機構におけるToll様受容体の関与

    Type of Award: Award from Japanese society, conference, symposium, etc.

  • 大学院生優秀発表者賞

    2014.05, マスト細胞関連疾患に対する創薬ツールとしての各種マスト細胞サブセットの分化誘導法の確立