Figure 5

Tau APFs in the brain and spinal cord of the P301L tauopathy mouse model. (a) Tau APFs were detected by dot blots of brain tissue from P301L mice probed with αAPF, with a peak at 10 months. (b) Tau APFs were detected in the brainstem of P301L mice with αAPF IHC. (c) Tau APFs were also detected in P301L brains by double immunofluorescence using Tau-5 (green) and αAPF (red). Double labeling using AT8 (green) and αAPF (red) revealed a lack of colocalization, indicating that tau APFs were not phosphorylated at epitopes Ser202/Thr205 or that the phospho epitopes are inaccessible. (d) Tau APFs in oligodendrocytes were confirmed by double labeling using MOG and αAPF. Tau APFs were detected in the neurons of P301L mouse brain by double labeling with NeuN and αAPF, but double labeling with GFAP and αAPF demonstrated that tau APFs were not found in astrocytes in P301L brains. (e) Tau APFs were detected in 10-month-old P301L spinal cord by double immunofluorescence using Tau-5 (green) and αAPF (red). A low level of colocalization indicates that tau APFs are sporadically phosphorylated at epitopes Ser202/Thr205, specifically in axonal spheroids in the spinal cord. (f) Double labeling with GFAP (green) and αAPF (red) demonstrates that tau APFs are formed in astrocytes in P301L spinal cord. Tau APFs were also detected in neurons in P301L spinal cord. This was confirmed by double staining with NeuN (green) and αAPF (red). The location of tau APFs in oligodendrocytes was confirmed by double labeling for MOG (green) and αAPF (red). The scale bars for HRP (b) and IF (c-f) corresponded to 10 and 20 μm, respectively. White arrows indicated colocalization.