Autoantibodies against aquaporin-5 in the sera from patients with Sjögren's syndrome.

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K08290
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Biological pharmacy
• Research Institution: Tokyo University of Science
• Principal Investigator: Isohama Yoichiro 東京理科大学, 薬学部薬学科, 教授 (10240920)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: シェーグレン症候群 / アクアポリン / 自己抗体 / 漢方薬

Outline of Final Research Achievements

Sjogren's syndrome (SJS), a systemic autoimmune disease targeting exocrine tissues. However, specific autoantibodies to cause selective pathogenesis in this disease have not been identified. Aquaporins-5 (AQP5), one of membrane water channels, is selectively expressed in exocrine glands. AQP5 knockout mice have shown dysfunction of fluid secretion in these tissues. In this study, we have found SjS patients possess autoantibodies against AQP5. This antibody causes internalization and degradation of AQP5, suggesting it may be related to SJS pathogenesis. We have also found that Seihaito, a traditional Oriental medicine attenuates abnormal localization and degradation of AQP5 induced by IgG from SJS patient. These data suggested anti-AQP5 may be a key factor to understand SJS pathogenesis, and to establish therapeutic strategy.

Free Research Field

生物型薬学

Academic Significance and Societal Importance of the Research Achievements

シェーグレン症候群は，自己免疫疾患ではあるが，その特徴的な病態をしめす原因となる自己抗体は不明であり，治療法についても乾燥症状に対して人工涙液や人工唾液などの対症療法に限られている．研究で，患者血清中に抗アクアポリン5自己抗体が存在することや，本抗体の機能が明らかになったことで，本疾患の病因解明の一助となる．また，漢方薬にこの自己抗体の作用を抑制する効果があることが見出されたことも，治療に新たな選択肢を与える情報として貴重である．