Details of a Researcher - KAMEKURA Ryuta

Papers - KAMEKURA Ryuta

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Interleukin 9 mediates T follicular helper cell activation to promote antibody responses

Taiki Sato, Ippei Ikegami, Masahiro Yanagi, Takeshi Ohyu, Taiki Sugaya, Shotaro Shirato, Masanobu Tanemoto, Shiori Kamiya, Kohei Kikuchi, Yuka Kamada, Takehito Nakata, Ryuta Kamekura, Akinori Sato, Ken-ichi Takano, Masahiro Miyajima, Atsushi Watanabe, Shingo Ichimiya

Frontiers in Immunology ( Frontiers Media SA ) 15 2024.09

Antigen-specific humoral responses are orchestrated through complex interactions among immune cells in lymphoid tissues, including the collaboration between B cells and T follicular helper (Tfh) cells. Accumulating evidence indicates a crucial role for interleukin-9 (IL-9) in the formation of germinal centers (GCs), enhancing the generation of class-switched high-affinity antibodies. However, the exact function of IL-9 in Tfh cell regulation remains unclear. In this study, we examined the humoral immune responses of CD4^Cre/+Il9ra^fl/fl mice, which lack an IL-9-specific receptor in Tfh cells. Upon intraperitoneal immunization with sheep red blood cells (SRBCs), CD4^Cre/+Il9ra^fl/fl mice displayed diminished levels of SRBC-specific IgG antibodies in their sera, along with reduced levels of GC B cells and plasma cells. Notably, Il9ra-deficient Tfh cells in the spleen exhibited decreased expression of their signature molecules such as B-cell lymphoma 6, C-X-C chemokine receptor 5, IL-4, and IL-21 compared to control mice. In models of allergic asthma induced by house dust mite (HDM) inhalation, CD4^Cre/+Il9ra^fl/fl mice failed to elevate serum levels of HDM-specific IgE and IgG. This was accompanied by reductions in Tfh cells, GC B cells, and plasma cells in mediastinal lymph nodes. Furthermore, group 2 innate lymphoid cells (ILC2s) were identified as producers of IL-9 under immunizing conditions, possibly induced by leukotrienes released by activated IgD⁺ B cells around the T-B border. These observations may indicate the critical role of IL-9 receptor signaling in the activation of Tfh cells, with ILC2s potentially capable of supplying IL-9 in organized lymphoid tissues.

DOI

Bob1 maintains T follicular helper cells for long-term humoral immunity.

Masahiro Yanagi, Ippei Ikegami, Ryuta Kamekura, Tatsuya Sato, Taiki Sato, Shiori Kamiya, Kosuke Murayama, Sumito Jitsukawa, Fumie Ito, Akira Yorozu, Miho Kihara, Takaya Abe, Hiromi Takaki, Koji Kawata, Katsunori Shigehara, Satsuki Miyajima, Hirotaka Nishikiori, Akinori Sato, Noritsugu Tohse, Ken-Ichi Takano, Hirofumi Chiba, Shingo Ichimiya

Communications biology 7 ( 1 ) 185 - 185 2024.02 [International journal]

Humoral immunity is vital for host protection, yet aberrant antibody responses can trigger harmful inflammation and immune-related disorders. T follicular helper (Tfh) cells, central to humoral immunity, have garnered significant attention for unraveling immune mechanisms. This study shows the role of B-cell Oct-binding protein 1 (Bob1), a transcriptional coactivator, in Tfh cell regulation. Our investigation, utilizing conditional Bob1-deficient mice, suggests that Bob1 plays a critical role in modulating inducible T-cell costimulator expression and cellular respiration in Tfh cells. This regulation maintains the long-term functionality of Tfh cells, enabling their reactivation from central memory T cells to produce antibodies during recall responses. In a bronchial asthma model induced by house dust mite (HDM) inhalation, Bob1 is observed to enhance HDM-specific antibodies, including IgE, highlighting its pivotal function in Tfh cell regulation. Further exploration of Bob1-dependent mechanisms in Tfh cells holds promise for governing protective immunity and addressing immune-related disorders.

DOI PubMed

Circulating T follicular helper 2 cells, T follicular regulatory cells and regulatory B cells are effective biomarkers for predicting the response to house dust mite sublingual immunotherapy in patients with allergic respiratory diseases

Katsunori Shigehara, Ryuta Kamekura, Ippei Ikegami, Hiroshi Sakamoto, Masahiro Yanagi, Shiori Kamiya, Kentaro Kodama, Yuichiro Asai, Satsuki Miyajima, Hirotaka Nishikiori, Eiji Uno, Keisuke Yamamoto, Kenichi Takano, Hirofumi Chiba, Hirofumi Ohnishi, Shingo Ichimiya

Frontiers in Immunology ( Frontiers Media SA ) 14 2023.11

The relationships between T follicular helper (Tfh) cells and antigen-specific immunoglobulins (sIgs) in patients with allergic respiratory diseases who are receiving antigen immunotherapy (AIT) have not been fully clarified. Therefore, we started to perform house dust mite sublingual immunotherapy (HDM-SLIT) for 20 patients with atopic asthma comorbid with allergic rhinitis (AA+AR) who were already receiving ordinary treatments including inhaled corticosteroid (ICS). We examined percentages of circulating T follicular helper (cTfh) and regulatory (cTfr) cells and percentages of circulating regulatory T (cTreg) and B (cBreg) cells by FACS and we examined levels of Der-p/f sIgs by ELISA. Based on the symptom score (asthma control questionnaire: ACQ) and medication score ((global initiative for asthma: GINA) treatment step score) in patients with AA, the patients were divided into responders and non-responders. The percentage of cTfh2 cells significantly decreased and the percentage of cTfh1 cells significantly increased within the first year. Der-p/f sIgEs decreased after a transient elevation at 3 months in both groups. Notably, the percentage of cTfh2 cells and the ratio of cTfh2/cBreg cells and Der-p/f sIgEs greatly decreased in responders from 6 months to 12 months. The percentages of cTfr and cTreg cells showed significant negative correlations with the percentage of cTfh2 cells. The percentage of IL-4⁺ cTfh cells were significantly decreased and the percentage of IFN-γ⁺ cTfh cells were increased before treatment to 24 months in 6 patients examined (4 responders and 2 non-responders). We performed multi plelogistic regression analysis based on these results, the ratios of cTfh2/cTfr cells and cTfh2/cBreg cells at the start of therapy were statistically effective biomarkers for predicting the response to HDM-SLIT in patients with AA+AR.

DOI

通年性アレルギー性鼻炎・各種鼻炎:治療・管理・診断ダニ舌下免疫療法の新しい効果発現のメカニズムの解明

亀倉隆太, 重原克則, 山本圭佑, 一宮慎吾, 高野賢一

アレルギー ( (一社)日本アレルギー学会 ) 72 ( 6-7 ) 872 - 872 2023.08

免疫療法・薬物療法(臨床) 鼻炎合併喘息患者におけるダニ舌下免疫療法のICS減量効果 3年間の解析

重原克則, 亀倉隆太, 宮島さつき, 小玉賢太郎, 錦織博貴, 千葉弘文

アレルギー ( (一社)日本アレルギー学会 ) 72 ( 6-7 ) 882 - 882 2023.08

喘息治療アレルギー性鼻炎合併喘息の家塵ダニ舌下免疫療法における吸入ステロイド減量効果

重原克則, 亀倉隆太, 宮島さつき, 小玉賢太郎, 柳昌弘, 錦織博貴, 千葉弘文

日本呼吸器学会誌 ( (一社)日本呼吸器学会 ) 12 ( 増刊 ) 185 - 185 2023.03

IgG4-related disease administered dupilumab: case series and review of the literature.

Masatoshi Kanda, Ryuta Kamekura, Masanari Sugawara, Ken Nagahata, Chisako Suzuki, Kenichi Takano, Hiroki Takahashi

RMD open 9 ( 1 ) 2023.03 [International journal]

Dupilumab (DUP) is a monoclonal antibody that acts on the interleukin (IL)-4 receptor alpha, which inhibits IL-4 and IL-13 signalling and is approved for type 2 inflammatory diseases such as asthma, chronic rhinosinusitis with nasal polyposis and atopic dermatitis; however, the efficacy of DUP to IgG4-related disease (IgG4-RD) is under discussion due to the controversial outcomes based on the several case reports. Here, we reviewed the efficacy of DUP in four consecutive patients with IgG4-RD in our institute and the previous literature.All patients administered DUP fulfilled the 2019 ACR/EULAR classification criteria for IgG4-RD complicated with severe asthma and chronic rhinosinusitis with nasal polyposis. Two cases were administered DUP without systemic glucocorticoids (GCs), and in 6 months, the volume of swollen submandibular glands (SMGs) was reduced by approximately 70%. Two cases receiving GCs successfully reduced their daily dose of GCs (10 and 50% reduction, respectively) with dupilumab in 6 months. In all four cases, serum IgG4 concentration and IgG4-RD responder index decreased in 6 months.DUP reduced the volume of the swollen SMGs, serum IgG4 levels, responder index and the daily dose of GCs in patients with IgG4-RD with severe asthma or eosinophilic rhinosinusitis in 6 months.The efficacy of DUP to IgG4-RD is under discussion due to the limited case reports with controversial outcomes. Here, we demonstrated that two patients with IgG4-RD treated by DUP without systemic GCs, showed volume reduction of swollen SMGs and two cases showed GC-sparing effects by DUP. DUP can ameliorate the disease activity and be a steroid-sparing agent in patients with IgG4-RD.

DOI PubMed

Tubarial gland involvement in IgG4-related diseases.

Kenichi Takano, Makoto Kurose, Ryuta Kamekura, Masatoshi Kanda, Motohisa Yamamoto, Hiroki Takahashi

Acta oto-laryngologica 1 - 4 2022.08 [International journal]

BACKGROUND: Tubarial glands (TGs) are a collection of unidentified salivary glands overlying the torus tubarius in the nasopharyngeal wall. Immunoglobulin G4-related disease (IgG4-RD) is a chronic fibroinflammatory state that often has multiple organ involvement. Involvement of the head and neck, especially the salivary glands, is common in IgG4-RD. AIMS/OBJECTIVES: This study aimed to elucidate the clinical significance of TGs in IgG4-RD. MATERIALS AND METHODS: We investigated the local findings of TGs in ten patients with IgG4-RD. RESULTS: Nasopharyngeal endoscopic examination revealed oedematous swelling of the nasopharyngeal wall surrounding the TGs, which improved after steroid treatment. Moreover, sonotubometry showed a stenotic pattern in three out of seven patients with IgG4-RD. CONCLUSIONS AND SIGNIFICANCE: TGs may be involved in IgG4-RD. The swollen TGs may be responsible for obstructive Eustachian tube dysfunction. Further studies are required to clarify the clinical significance and physiological roles of TGs in IgG4-RD.

DOI PubMed

アレルゲン・抗原・免疫療法・検査法ダニ舌下免疫療法における濾胞Tヘルパー細胞と特異的Igの2年間解析

重原克則, 亀倉隆太, 柳昌弘, 錦織博貴, 一宮慎吾

アレルギー ( (一社)日本アレルギー学会 ) 71 ( 6-7 ) 817 - 817 2022.08

CD4+CD8+ T follicular helper cells regulate humoral immunity in chronic inflammatory lesions.

Kosuke Murayama, Ippei Ikegami, Ryuta Kamekura, Hiroshi Sakamoto, Masahiro Yanagi, Shiori Kamiya, Taiki Sato, Akinori Sato, Katsunori Shigehara, Motohisa Yamamoto, Hiroki Takahashi, Ken-Ichi Takano, Shingo Ichimiya

Frontiers in immunology 13 941385 - 941385 2022 [International journal]

T follicular helper (Tfh) cells drive humoral immunity by facilitating B cell responses at the initial and recall phases. Recent studies have indicated the possible involvement of Tfh cells in the process of chronic inflammation. However, the functional role of Tfh cells in persistent immune settings remains unclear. Here, we report that CD4+CD8+ (double-positive, DP; CD3+CD4+CD8+CXCR5hiPD-1hi) Tfh cells, a subset of germinal-center-type Tfh cells, were abundantly present in the fibroinflammatory lesions of patients with immunoglobulin G4-related disease (IgG4-RD). Transcriptome analyses showed that these DP-Tfh cells in the lesions of IgG4-RD preferentially expressed signature genes characteristic of cytotoxic CD8+ T cells, such as Eomes, CRTAM, GPR56, and granzymes, in addition to CD70. Scatter diagram analyses to examine the relationships between tissue-resident lymphocytes and various clinical parameters revealed that the levels of DP-Tfh cells were inversely correlated to the levels of serum IgG4 and local IgG4-expressing (IgG4+) memory B cells (CD19+CD27+IgD-) in patients with IgG4-RD. Cell culture experiments using autologous tonsillar lymphocytes further suggested that DP-Tfh cells possess a poor B-cell helper function and instead regulate memory B cells. Since CD4+ (single positive, SP; CD3+CD4+CD8-CXCR5hiPD-1hi) Tfh cells differentiated into DP-Tfh cells under stimulation with IL-2 and IL-7 as assessed by in vitro experiments, these data imply that SP-Tfh cells are a possible origin of DP-Tfh cells under persistent inflammation. These findings highlight the potential feedback loop mechanism of Tfh cells in immune tolerance under chronic inflammatory conditions. Further studies on DP-Tfh cells may facilitate control of unresolved humoral responses in IgG4-RD pathological inflammation.

DOI PubMed

アレルギー性炎症疾患の病態形成における免疫系の役割細胞傷害性Tph細胞のオリゴクローナルな増殖がIgG4関連疾患の病態形成に関与する

亀倉隆太, 村山公介, 山本圭佑, 重原克則, 高野賢一, 一宮慎吾

アレルギー ( (一社)日本アレルギー学会 ) 70 ( 6-7 ) 817 - 817 2021.08

免疫療法鼻炎合併喘息患者におけるダニ舌下免疫療法の濾胞ヘルパー及び濾胞制御性T細胞を中心とした解析

重原克則, 亀倉隆太, 池上一平, 柳昌弘, 山本圭佑, 一宮慎吾

アレルギー ( (一社)日本アレルギー学会 ) 70 ( 6-7 ) 789 - 789 2021.08

Cytotoxic Tph-like cells are involved in persistent tissue damage in IgG4-related disease

Hayato Yabe, Ryuta Kamekura, Motohisa Yamamoto, Kosuke Murayama, Shiori Kamiya, Ippei Ikegami, Katsunori Shigehara, Hiromi Takaki, Hirofumi Chiba, Hiroki Takahashi, Kenichi Takano, Hiroki Takahashi, Shingo Ichimiya

Modern Rheumatology ( Informa UK Limited ) 31 ( 1 ) 249 - 260 2021.01 [International journal]

OBJECTIVES: The aim of this study was to determine pathological features of T peripheral helper (Tph)-like (PD-1+CXCR5-CD4+ T) cells in IgG4-related disease (IgG4-RD). METHODS: Tph-like cells in the blood and submandibular glands (SMGs) from IgG4-RD patients were analyzed by flow cytometry. Correlations between level of a Tph-like cell subset and clinical parameters of IgG4-RD were investigated. The cytotoxic capacity of Tph-like cells was also examined. Expression profiles of a molecule related to a Tph-like cell subset in IgG4-RD SMGs were assessed by immunohistochemistry. RESULTS: Tph-like cells from IgG4-RD patients highly expressed a fractalkine receptor, CX3CR1. Percentages of circulating CX3CR1+ Tph-like cells were significantly correlated with clinical parameters including IgG4-RD Responder Index, number of involved organs, and serum level of soluble IL-2 receptor. CX3CR1+ Tph-like cells abundantly possessed cytotoxic T lymphocyte-related molecules such as granzyme A, perforin, and G protein-coupled receptor 56. Functional assays revealed their cytotoxic potential against vascular endothelial cells and ductal epithelial cells. Immunohistochemistry showed that fractalkine was markedly expressed in vascular endothelial cells and ductal epithelial cells in IgG4-RD SMGs. CONCLUSION: CX3CR1+ Tph-like cells are thought to contribute to persistent tissue injury in IgG4-RD and are a potential clinical marker and/or therapeutic target for inhibiting progression of IgG4-RD.

DOI PubMed

ダニSLIT中のアレルギー性鼻炎合併喘息における末梢血濾胞ヘルパーT細胞の検討

重原克則, 亀倉隆太, 矢部隼人, 針生寛之, 宇野英二, 一宮慎吾

日本呼吸器学会誌 ( (一社)日本呼吸器学会 ) 9 ( 増刊 ) 324 - 324 2020.08

Activated circulating T follicular helper cells and skewing of T follicular helper 2 cells are down-regulated by treatment including an inhaled corticosteroid in patients with allergic asthma.

Satsuki Miyajima, Katsunori Shigehara, Ryuta Kamekura, Hiromi Takaki, Hayato Yabe, Ippei Ikegami, Yuichiro Asai, Hirotaka Nishikiori, Hirohumi Chiba, Eiji Uno, Hiroki Takahashi, Shingo Ichimiya

Allergology international : official journal of the Japanese Society of Allergology 69 ( 1 ) 66 - 77 2020.01 [International journal]

BACKGROUND: CXCR5+ T follicular helper (TFH) cells primarily promote B cells to produce an antigen-specific antibody through germinal centers (GCs). TFH cells exist in circulation, and circulating(c) TFH2 cells, a subset of cTFH cells, are able to help naïve B cells produce IgE in healthy individuals. Conversely, IL-10-producing regulatory B (Breg) cells inhibit an accelerated immune response. METHODS: We investigated the roles of cTFH cells and cBreg cells based on a TH2 response in patients with atopic asthma (AA). Thirty-two patients with AA and 35 healthy volunteers (HV) were enrolled. We examined cTFH cells including their subsets, their expression of ICOS and PD-1, and cBreg cells by flow cytometry and their associations with clinical biomarkers. Plasma levels of CXCL13, which is a counterpart of CXCR5, were also measured using ELISA. RESULTS: In patients with AA, cTFH2 cells were increased and cTFH1 cells were decreased compared with those in HV. The expression levels of ICOS on cTFH and their subset cells were elevated and Breg cells were greatly decreased. The plasma levels of CXCL13 in patients with AA were significantly elevated and correlated well with the cTFH2/cBreg ratio. These cells were examined in 10 patients AA before and after inhaled corticosteroid (ICS) treatment. Interestingly, the percentages and numbers of TFH2 and ICOS+ cTFH cells declined after ICS treatment together with improvements in symptoms and clinical biomarkers. CONCLUSIONS: The percentages and numbers of cTFH2 and ICOS+ cTFH cells might be useful as biomarkers of TH2 typed airway inflammation in patients with AA.

DOI PubMed

IgG4 関連疾患の免疫病態と治療への展望.

亀倉隆太, 一宮慎吾

リウマチ科 64 559 - 566 2020

Aberrant populations of circulating T follicular helper cells and regulatory B cells underlying idiopathic pulmonary fibrosis.

Yuichiro Asai, Hirofumi Chiba, Hirotaka Nishikiori, Ryuta Kamekura, Hayato Yabe, Shun Kondo, Satsuki Miyajima, Katsunori Shigehara, Shingo Ichimiya, Hiroki Takahashi

Respiratory research 20 ( 1 ) 244 - 244 2019.11 [International journal]

BACKGROUND: T follicular helper (Tfh) cells have been identified as a new category of helper T cells, which express CXCR5 on their surface and induce the production of antigen-specific antibodies. Many investigations have found morbid proliferation and/or activation of Tfh cells in systemic autoimmune and allergic diseases. It is also known that Tfh cells are regulated by regulatory B (Breg) cells in the deteriorating such diseases. Recently, CXCL13, a ligand of CXCR5, has been reported to increase in the peripheral blood and lungs of patients with idiopathic pulmonary fibrosis (IPF). This study aimed to investigate the involvement of Tfh cells and Breg cells in IPF. METHODS: Peripheral blood samples were obtained from 18 patients with IPF. We isolated heparinized peripheral blood mononuclear cells and investigated the proportions of Breg cells, Tfh cells, PD-1+ICOS+ Tfh cells (activated form of Tfh cells), and the Tfh-cell subsets by flow cytometry. These cell profiles were compared with those of 21 healthy controls. Furthermore, we investigated the correlations between profiles of lymphocytes and lung physiology. RESULTS: The median proportions of Tfh cells per total CD4+ T cells and of PD-1+ICOS+ proportion of Tfh cells per total Tfh cells was significantly more in the IPF patients (20.4 and 5.2%, respectively) compared with healthy controls (15.4 and 2.1%, respectively; p = 0.042 and p = 0.004, respectively). The proportion of Tfh2 cells per total Tfh cells was significantly higher and the proportion of Tfh17 was smaller in the IPF patients than healthy controls. The percentage of Breg cells to total B cells was significantly decreased in the IPF patients (median, 8.5%) compared with that in the controls (median, 19.7%; p < 0.001). The proportion of Breg cells was positively correlated with the annual relative change in diffusing capacity of the lungs for carbon monoxide in the IPF patients (r = 0.583, p = 0.018). CONCLUSION: Proliferation and activation of Tfh cells and a decrease in Breg cells were observed in the peripheral blood of patients with IPF. The profile of the Tfh-cell subset also changed. Specific humoral immunity aberration would likely underlie complicated pathophysiology of IPF.

DOI PubMed

Interleukin 5-producing ST2<sup>+</sup> memory Th2 cells in IgG4-related dacryoadenitis and sialadenitis.

Yamamoto M, Takano KI, Kamekura R, Aochi S, Suzuki C, Ichimiya S, Nakase H, Himi T, Takahashi H

Modern rheumatology ( TAYLOR & FRANCIS LTD ) 29 ( 5 ) 856 - 860 2019.09 [Refereed]

Objectives: Immunoglobulin (Ig) G4-related disease (IgG4-RD) is often complicated by allergic disorders. This study was conducted to investigate the mechanism of type 2 helper T-inflammation (Th2-inflammation) in IgG4-related dacryoadenitis and sialadenitis (IgG4-DS). Methods: We separated and analyzed the proportion of growth stimulation expressed gene 2 (ST2)(+) memory Th2 cells among the peripheral blood mononuclear cells by flow cytometry in cases with IgG4-DS and healthy individuals. Finally, we identified the role of ST2(+) memory Th2 cells in the involved tissues. Results: The proportion of circulating ST2(+) memory Th2 cells was much higher in the patients with IgG4-DS than in the healthy controls. Abundant infiltration of ST2(+) memory Th2 cells was detected in the involved salivary glands and lymph nodes, and these cells produced interleukin-5. Conclusion: We demonstrated that there is an increase of interleukin-5 producing ST2(+) memory Th2 cells in the involved tissues in IgG4-DS. This subset of cells is considered to be an important player in inducing the inflammatory Th2 environment characteristic of IgG4-DS.

DOI PubMed

Bob1 enhances RORγt-mediated IL-17A expression in Th17 cells through interaction with RORγt.

Ikegami I, Takaki H, Kamiya S, Kamekura R, Ichimiya S

Biochemical and biophysical research communications ( Elsevier BV ) 514 ( 4 ) 1167 - 1171 2019.07 [Refereed]

DOI PubMed

生体バリア機構とアレルギー疾患アレルギー性鼻炎に関連するエピイムノームの新機能

亀倉隆太, 矢部勇人, 重原克則, 高野賢一, 一宮慎吾

アレルギー ( (一社)日本アレルギー学会 ) 68 ( 4-5 ) 320 - 320 2019.05

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Papers - KAMEKURA Ryuta