Creutzfeldt-Jakob Disease Research Today is a free monthly online journal that collates and summarizes the latest research about Creutzfeldt-Jakob Disease, including details on mad cow disease, symptoms, causes, variants.

Close association of water channel AQP1 with amyloid-beta deposition in Alzheimer disease brains.

Misawa T, Arima K, Mizusawa H, Satoh JI

Department of Bioinformatics and Molecular Neuropathology, Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose, Tokyo, 204-8588, Japan.

Aquaporin-1 (AQP1), a membrane water channel protein, is expressed exclusively in the choroid plexus epithelium in the central nervous system under physiological conditions. However, AQP1 expression is enhanced in reactive astrocytes, accumulating in brain lesions of Creutzfeldt-Jakob disease and multiple sclerosis, suggesting a role of AQP1-expressing astrocytes in brain water homeostasis under pathological conditions. To clarify a pathological implication of AQP1 in Alzheimer disease (AD), we investigated the possible relationship between amyloid-beta (Abeta) deposition and astrocytic AQP1 expression in the motor cortex and hippocampus of 11 AD patients and 16 age-matched other neurological disease cases. In all cases, AQP1 was expressed exclusively in a subpopulation of multipolar fibrillary astrocytes. The great majority of AQP1-expressing astrocytes were located either on the top of or in close proximity to Abeta plaques in AD brains but not in non-AD cases, whereas those independent of Abeta deposition were found predominantly in non-AD brains. By Western blot, cultured human astrocytes constitutively expressed AQP1, and the levels of AQP1 protein expression were not affected by exposure to Abeta(1-42) peptide, but were elevated by hypertonic sodium chloride. By immunoprecipitation, the C-terminal fragment-beta (CTFbeta) of amyloid precursor protein interacted with the N-terminal half of AQP1 spanning the transmembrane helices H1, H2 and H3. These observations suggest the possible association of astrocytic AQP1 with Abeta deposition in AD brains.

Published 29 May 2008 in Acta Neuropathol.
Full-text of this article is available online (may require subscription).

© 2005-2008 Creutzfeldt-Jakob Disease Research Today. All Rights Reserved.