Mechanism and physiological role of urinary excretion of aquaporin-2

2018 Fiscal Year Final Research Report

• Project/Area Number: 15K09301
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Kidney internal medicine
• Research Institution: Meiji Pharmaceutical University
• Principal Investigator: SASAKI SEI 明治薬科大学, 薬学部, 客員研究員 (60170677)
• Co-Investigator(Kenkyū-buntansha): 田中 靖子 明治薬科大学, 薬学部, 講師 (20386452) ; 石橋 賢一 明治薬科大学, 薬学部, 教授 (80223022)
• Project Period (FY): 2015-04-01 – 2019-03-31
• Keywords: アクアポリン / 水代謝 / 尿濃縮 / エクソソーム / 腎臓 / バソプレシン / 膜輸送 / 水透過性

Outline of Final Research Achievements

Aquaporin-2 is water channel located in kidney collecting duct, and plays an essential role in urinary concentration. We clarified that 1) urine AQP2 is excreted in exosomes through endocytosis-MVB pathway, 2) disruption of exosome membrane is required for accurate measurement of urine AQP2 by ELISA, 3) urine AQP2 is an useful biomarker for clinical water metabolism disorders, 4) AQP2 in exosome preserves its original water channel function, 5) urinary excretion of AQP2 is responsive to vasopressin and shows long- and short-term regulations mediated by multiple phosphorylation of AQP2.

Free Research Field

腎臓内科

Academic Significance and Societal Importance of the Research Achievements

学術的にはエクソソームに存在する膜タンパクが本来の機能を保持していること示したことが注目される。エクソソームの生体での新しい役割が今後明らかになるだろう。
社会的にはAQP2の臨床応用に耐えるELISA測定法の確立は意義深い。今後臨床応用が進むことが期待される。