Loss of astrocyte polarization in the tg-ArcSwe mouse model of Alzheimer's disease.

Aquaporin-4 (AQP4) is the predominant water channel in brain and is selectively expressed in astrocytes. Astrocytic endfoot membranes exhibit tenfold higher densities of AQP4 than non-endfoot membranes, making AQP4 an excellent marker of astrocyte polarization. Loss of astrocyte polarization is known to compromise astrocytic function and to be associated with impaired water and K+ homeostasis.

Amyloid deposits show complexity and intimate spatial relationship with dendrosomatic plasma membranes: an electron microscopic 3D reconstruction analysis in 3xTg-AD mice and aged canines.

Little is known about how amyloid-beta (Abeta) is deposited in relation to the complex ultrastructure of the brain. Here we combined serial section immunoelectron microscopy with 3D reconstruction to elucidate the spatial relationship between Abeta deposits and ultrastructurally identified cellular compartments. The analysis was performed in a transgenic mouse model with mutant presenilin-1, and mutant amyloid-beta protein precursor (AbetaPP) and tau transgenes (3xTg-AD mice) and in aged dogs that develop Abeta plaques spontaneously.