Establishment of endomembrane potential optical imaging

• Project/Area Number: 18K06873
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 48020:Physiology-related
• Research Institution: Osaka University
• Principal Investigator: Okochi Yoshifumi 大阪大学, 医学系研究科, 准教授 (90435818)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Project Status: Completed (Fiscal Year 2021)
• Budget Amount: ¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000); Fiscal Year 2020: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2019: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000); Fiscal Year 2018: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
• Keywords: 膜電位 / voltage probe / ファゴソーム膜 / ファゴソーム / BKチャネル / 過分極 / カルシウム / イメージング / イオンチャネル / 内膜 / 蛍光タンパク / 貪食細胞 / アクチン重合 / エンドソーム

Outline of Final Research Achievements

Several ion channels including voltage-gated ion channel has been identified in organelles, which suggests that membrane potential in endomembranes regulates organelle and whole cell functions. However, no reliable technique measuring membrane potential quantitatively has been established. In this study, we have developed a method measuring membrane potential in a living cell by using voltage probe Merm2. By focusing on phagosome, which is formed in phagocytes to eliminate pathogens from our body, we successfully visualized membrane potential change on phagosome and estimated membrane potential from fluorescent signal obtained.

Academic Significance and Societal Importance of the Research Achievements

本研究により、初めてファゴソームの膜電位がダイナミックに変化することが明らかになった。この結果は膜電位シグナルがファゴソーム機能を制御する可能性を示唆する。今後、この方法を用いてファゴソーム機能異常の原因を膜電位の観点から調べることで、ファゴソーム機能異常に起因する病気の原因の詳細を明らかにできると期待される。この結果は、また、リソソームなどの細胞内小器官の膜電位を測定する技術への応用が期待される。

Research Products

• [Journal Article] Regulation of Neutrophil Functions by Hv1/VSOP Voltage-Gated Proton Channels (2021)
  • Author(s): Okochi Yoshifumi、Okamura Yasushi
  • Journal Title: International Journal of Molecular Sciences Volume: 22 Issue: 5 Pages: 2620-2620
  • DOI: 10.3390/ijms22052620
  • Peer Reviewed / Open Access
• [Journal Article] Hv1/VSOP regulates neutrophil directional migration and ERK activity by tuning ROS production. (2020)
  • Author(s): Okochi Y, Umemoto E, Okamura Y.
  • Journal Title: Journal of Leukocyte Biology Volume: 107 Issue: 5 Pages: 819-831
  • DOI: 10.1002/jlb.2a0320-110rr
  • Peer Reviewed / Open Access
• [Journal Article] TRPM5 Negatively Regulates Calcium-Dependent Responses in Lipopolysaccharide-Stimulated B Lymphocytes (2020)
  • Author(s): Sakaguchi Taiki、Okumura Ryu、Ono Chisato、Okuzaki Daisuke、Kawai Takafumi、Okochi Yoshifumi、Tanimura Natsuko、Murakami Mari、Kayama Hisako、Umemoto Eiji、Kioka Hidetaka、Ohtani Tomohito、Sakata Yasushi、Miyake Kensuke、Okamura Yasushi、Baba Yoshihiro、Takeda Kiyoshi
  • Journal Title: Cell Reports Volume: 31 Issue: 10 Pages: 107755-107755
  • DOI: 10.1016/j.celrep.2020.107755
  • Peer Reviewed / Open Access
• [Journal Article] Regulation of hepatic oxidative stress by voltage‐gated proton channels (Hv1/VSOP) in Kupffer cells and its potential relationship with glucose metabolism (2020)
  • Author(s): Kawai Takafumi、Kayama Kento、Tatsumi Shoki、Akter Sharmin、Miyawaki Nana、Okochi Yoshifumi、Abe Manabu、Sakimura Kenji、Yamamoto Hiroyasu、Kihara Shinji、Okamura Yasushi
  • Journal Title: The FASEB Journal Volume: 34 Issue: 12 Pages: 15805-15821
  • DOI: 10.1096/fj.202001056rrr
  • Peer Reviewed / Open Access
• [Journal Article] Distinct functional properties of two electrogenic isoforms of the SLC 34 Na‐Pi cotransporter (2019)
  • Author(s): Mizutani Natsuki、Okochi Yoshifumi、Okamura Yasushi
  • Journal Title: Physiological Reports Volume: 7 Issue: 14
  • DOI: 10.14814/phy2.14156
  • Peer Reviewed / Open Access
• [Presentation] SLC34 Na+/Pi トランスポーターのリン酸輸送機能の理解 (2022)
  • Author(s): 大河内善史, 周俊先, 水谷夏希, 塩﨑雄治, 瀬川博子, 岡村康司
  • Organizer: 第99回日本生理学会大会
• [Presentation] Method of measuring the membrane potential of phagosomes by optical imaging (2021)
  • Author(s): Yoshifumi Okochi, Hidekazu Tsutsui, Yasushi Okamura
  • Organizer: 74th Annual Meeting and Symposium of the Society of General Physiologists Ion Channels & Transporters in Immunity, Inflammation and Antitumor Immunity
  • Int'l Joint Research
• [Presentation] マクロファージのファゴソーム膜電位変化を可視化し、膜電位の役割を探る (2021)
  • Author(s): 大河内 善史, 筒井 秀和, 岡村 康司
  • Organizer: 第98回日本生理学会大会
  • Invited
• [Presentation] Establishment of a method measuring membrane potential in phagosomes. (2020)
  • Author(s): Okochi Y, Tsutsui H, Okamura Y.
  • Organizer: 第97回日本生理学会大会
• [Presentation] Analysis of membrane potential of phagosome in phagocytes. (2019)
  • Author(s): Okochi Y, Tsutsui H, Okamura Y.
  • Organizer: 60th International Conference on the Bioscience of Lipids（ICBL2019）
  • Int'l Joint Research
• [Presentation] Measurement o f membrane potential change in phagosome of phagocytes (2018)
  • Author(s): Yoshifumi Okochi, Hidekazu Tsutsui and Yasushi Okamura
  • Organizer: 第95回日本生理学会大会
• [Presentation] Toward understanding of membrane potential in phagosomal membrane (2018)
  • Author(s): Yoshifumi Okochi, Hidekazu Tsutsui, Yasushi Okamura
  • Organizer: The 49th NIPS International Symposium: Ion channels: looking back, seeing ahead
  • Int'l Joint Research