Fig. 6: Plexin-B3+ senile plaques (SPs) in AD brains.

a Cortical distribution of plexin-B3⁺ SPs in an AD brain Scale bar: 5 mm. b Enlarged image of the rectangular area in a (see also Supplementary Fig. 10). Scale bar: 200 μm. c, d Specificity of the anti-plexin-B3 polyclonal antibody against human plexin-B3 (See also Supplementary Fig. 11). Spatial relationship between plexin-B3⁺ and Aβ⁺ areas as analyzed based on the combination of phase contrast (e) and confocal images (f–h). Scale bar in d: 20 μm. See also Supplementary Fig. 12. i–l Fluorescent immunostaining of plexin-B3, CD68 (a marker for microglia), and GFAP in an SP. Scale bar: 20 μm. m Increased plexin-B3 levels in the Sarkosyl-soluble fractions of AD brains (BA6). Two major bands of plexin-B3 are observed (at 200 kDa, indicated by an arrow and marked “o” and around 130 kDa, indicated by an arrowhead and marked “p”). Note that a postmortem interval increased the intensity of the 130 kDa plexin-B3 band in the rat brains. Rat 0 & Rat 70: adult rat brain homogenate with 0 or 70 h postmortem intervals, respectively. Molecular weight marker: 200 kDa. n Accumulation of tau abnormally hyperphosphorylated at Ser396 (PS396) in the Sarkosyl-insoluble fractions of the AD brains. Braak stages (I–VI) are also specified below the blot. Note that abnormal tau accumulation in the AD BA6 is associated with Braak stage. Molecular weight markers: 87 and 35 kDa. o, p Quantification of the intensity of the plexin-B3 bands in panel m. Adjusted arbitrary units were plotted on the Y-axis (n = 8/group; **P < 0.01, ***P < 0.001; unpaired t-test). q A significant correlation is observed between plexin-B3 levels (arbitrary units; “o” + “p”) and Braak stages (Pearson’s correlation coefficient: r = 0.7838, P = 0.0003).