アクアポリンと神経疾患

Roles of Aquaporins in Brain Disorders

アクアポリンの発見から20年が過ぎた。アクアポリンの分子生物学的，生化学的研究はかなり進展したといえるが，まだまだ未解決の問題も多い。中枢神経系で発現しているアクアポリン4は視神経脊髄炎や脳浮腫の病態との関連が明らかとなり，臨床的にもその重要性が認識された。さらに脳のリンパ流にも関与していることから，神経変性疾患や精神神経疾患との関係も指摘されている。アクアポリン4機能の解明と創薬が期待される。

Abstract

Aquaporin (AQP) is a water channel protein that is expressed in the cell membranes. AQPs are related to several kinds of human diseases such as cataract. In the mammalian central nervous system (CNS), AQP4 is specifically expressed in the astrocyte membranes lining the perivascular and periventricular structures. AQP4 plays a role in the development of brain edema associated with certain brain disorders. Neuromyelitis optica (NMO) is a demyelinating disorder, and patients with NMO develop autoimmune antibodies against AQP4 in their serum. Therefore, AQP4 is involved in NMO pathogenesis. A new concept referred to as "glymphatic pathway" has been recently proposed to explain the lymphatic system in the CNS. Dysfunction of the "glymphatic pathway" may cause several neurodegenerative diseases and mood disorders. Importantly, AQP4 may play a role in the "glymphatic pathway". Further investigation of AQP4 in CNS disorders is necessary, and a new drug against AQP4 is expected.