(A) AVs clustering within swollen/dystrophic neurites around an amyloid plaque enriched with 6E10 antibody-labeled APP, C99, or Aβ deposits. (B and C) Representative images (B) and quantitative analysis (C) showing that soluble Aβ oligomers labeled by anti-A11 antibody was concentrated within Neurofilament (NF)-labeled axons surrounding amyloid plaques in mutant hAPP Tg mice. The percentage of soluble Aβ co-localization with 6E10 antibody-labeled Aβ or NF was quantified, respectively. (D and E) Quantitative analysis (D) and representative images (E) showing the association of soluble Aβ oligomers with amphisomes within dystrophic axons around amyloid plaques in the hippocampal regions of mutant hAPP mice. The percentage of oligomeric Aβ co-localization with CI-MPR, p62, and Ubiquitin (Ub) was quantified, respectively. (F–I) Immuno-EM analysis (I) and quantification (F, G, and H) showing that soluble Aβ oligomers in the cytoplasm, marked by anti-A11 immuno-gold particles (white arrows), associated with or surround AVd-like structures (black arrows) within the neurites of cultured mutant hAPP Tg neurons. Note that anti-A11 immuno-gold particles were also present within the AVd-like structures containing organelles and small vesicles along hAPP neurites. Anti-A11 immuno-gold particles were detected in the cytoplasm of neurites in WT neurons. The average numbers of the A11 gold grains per EM field (10 μm × 10 μm) and per 10 μm neurite were quantified in WT and hAPP neurons, respectively. The percentage of AVd-like compartments surrounded by the gold particles was quantified in hAPP neurons or in the absence of the primary antibody. The co-localized pixels of individual markers with Aβ oligomers were indicated in white (B and E). Data were quantified from a total number of imaging slice sections (320 μm × 320 μm) indicated on the top of bars (C and D) and from a total number of EM fields (F), neurites (G), or AVs (H) indicated in parentheses from more than three experiments. Scale bars: 25 μm (A), 10 μm (B and E), and 200 nm (I). Error bars represent SEM. Student’s t test: ***p<0.001, **p<0.01, *p<0.05.