Extended Data Fig. 8. Thalamic plaques contain Aβ derived from cortical and hippocampal sources and plaque deposition is not directly proportional to APPNLGF gene dosage.
(a) Fluorescence microscopy images of thalami of control and ExN-Bace1cKO;AD samples with no apparent reduction in Bace1 transcripts in ExNs. (b) Violin plots showing individual mouse distribution of Bace1 puncta/thalamic nuclei. Solid lines represent medians and faded lines represent quartiles. (c) Isocortical regions containing neuronal projections into the thalamus (left) and the inferior colliculus (right). Inferior colliculus primarily receives cortical input from the auditory cortex. Images were adapted from the Allen Brain Atlas: Mouse Connectivity: Projection (https://connectivity.brain-map.org/). (d) Fluorescence microscopy images of 5xFAD mouse cortex (left) and thalamus (right) stained for Aβ42 (blue) and human-specific APP (yellow). White arrowheads point to neuronal somas in the cortex but not the thalamus of 5xFAD mice positive for human-specific APP. Immunolabeling was performed once on brain slices of 6-month-old 5xFAD mice (n = 4) (e-g) Plaque deposition is not directly proportional to APPNLGF gene dosage. (e) LSM 3D visualization of female WT, heterozygous, and homozygous APPNLGF hemibrains at 6 months of age. (f) Quantification of LSM data between female homozygous (n = 10) and heterozygous APPNLGF mice (n = 7). Heterozygous data points were normalized to homozygous data. Circles represent homozygous APPNLGF mice and half-filled circles represent heterozygous APPNLGF mice. For each parameter, unpaired, two-tailed Student’s t-test was performed (P values indicated in graphs) comparing the two groups. Bars represent means with SEM and individual data points displayed. Raw unnormalized data is available in Supplementary Table 3. (g) Immunoblot of 6-month-old male homozygous APPNLGF, heterozygous APPNLGF, and WT mice labeled for APP (n = 2 per group). Heterozygous mice express half of the APPNLGF gene dosage, resulting in a FL-APP level between WT and homozygous APPNLGF mice. This is accompanied by a concomitant accumulation of half β-CTFs in heterozygous lysates compared to the homozygous amount.