Fig. 4: WAM forms nodules at aging fiber tracts.

A Immunofluorescence microscopy showing the expression of LGALS3 (green) and AIF1 (red) -positive microglia in mouse hemisphere sections with nuclear staining with DAPI (blue). Scale bars are 500 µm. The white insets are magnified on the right and show the corpus callosum and corticospinal tracts in the young and old brain. B Confocal images showing expression of LGALS3 (green) and AIF1 (red) -positive microglia in the corpus callosum area. C Same as (B) except showing corticospinal tract area. For (B, C), scale bars are 50 µm. D Clipped 3D images showing LGALS3 (green) and AIF1 (red) -positive microglia in the corpus callosum of young and old mice. Scale bars are 15 µm. E Bar plot showing quantification of AIF-positive microglia in five fields from corpus callosum and corticospinal tract region per mouse (n = 3 mice per group; average age, young = 14.67 weeks, old = 85.67 weeks). F Bar plot showing the fraction of LGALS3 and AIF1 double positive microglia nodules (18.2%) and LGALS3 and AIF1 single positive microglia (81.8%) quantified from the same fields as (E). Data were summarized as mean ± standard error of the mean fraction value of 15 fields of three mice. G Confocal images showing expression of GFAP (green) in the corpus callosum. Scale bars are 50 µm. H Bar plot showing quantification of GFAP-positive cells from five fields in the corpus callosum and corticospinal tract area per mouse (n = 3 mice per group; average age, young = 14.67 weeks, old = 85.67 weeks. For (E, H), data were summarized as mean ± standard error of the mean cell number from 15 fields of three mice. p values are reported from an unpaired two-tailed t-test with Welch’s correction comparing old vs young. Source data are provided as a Source Data file.