Figure 3.

S100A9 expression in neuronal cell culture. (A) Fluorescence immunocytochemistry images by confocal microscopy of wild-type (WT) mouse primary neurons treated with Aβ₄₂ oligomers. DAPI nuclei staining shown in blue and Aβ₄₂ specific fluorescence – in green. Neurons before (B) and after Aβ₄₂ oligomer treatment (C), respectively, with S100A9 content manifested in red fluorescence. (D) Quantification of S100A9 specific immunofluorescence signal per cell by using an Imaris software in untreated neurons (purple bar) and Aβ₄₂ oligomer treated neurons (dark blue bar); the procedure is shown in Supplementary Fig. S7. Bars present means ± standard deviations in arbitrary units out of n = 7 and n = 6 measurements of untreated and treated cells, respectively. ***p < 0.0001 by Student’s t test. Scale bars are 30 µm (A), 15 µm (B) and 20 µm (C).