Fig. 4

Tau deposits associated with the neuronal marker MAP2. A Representative image of the granular layer of the hippocampus showing the presence of tau deposits (green) and their association with the neuronal microtubule associated protein MAP2 (red) and the astrocyte endfeet marker AQP4 (white) with DAPI⁺ nuclei (blue). The region is represented as a single channel of tau-1, 3-channel overlays of DAPI/tau/MAP2 and DAPI/tau/AQP4 and as a 4-channel overlay of DAPI/tau/MAP2/AQP4. Tau (green) and MAP2 (red) colocalization is evident from the yellow signal of the aggregates in the merged or overlaid channels. The multi-channel confocal image was taken using 100x objective/1.45 NA and 2.188x scanner zoom. Scale bar 5 μm. B The ROI in A is cropped to show a higher zoom of the tau (green) association with MAP2 (red) and AQP4 (white) expression. The MAP2 neuronal microtubules wrapping the tau-1 aggregates generate the yellow colocalized signal as indicated in the 2- and 3-channel merged images. These neuronal tau aggregates were detected in conjunction with the AQP4-positive disc-like structures which constitute the neuron-facing membrane domains of astrocytes (n-AQP4). C Three-dimensional (3D) orthogonal slice view also indicates the tau deposits to be wrapped by neuronal MAP2 and nAQP4 astrocytic domains. Scale bars 5 μm. D The pyramidal layer of the hippocampus is showing a similar occurrence of tau deposits (green) and association with neuronal MAP2 (red) and AQP4⁺ astrocytes (white). Image taken using a 100x objective/1.45 NA. Scale bar 25 μm. E The region indicated by the ROI in (D) captured at a higher magnification and represented as a single, and 3- and 4-channel overlaid images. F 3D-orthogonal slice and (G) 3D-volume views depicting the occurrence of the tau deposits and their association with neurons and astrocytes. Images taken using a 100x objective/1.45 NA and 2.188 scanner zoom. Scale bar 5 μm. H Entorhinal cortex showing the distribution of tau deposits, colocalized with neuronal MAP2 and associated with AQP4. Image taken using a 100x objective/1.45 NA. Scale bar 5 μm.