Fig. 4. Migrasomes derived from macrophages upon Aβ40 stimulation directly cause brain blood vessel damage.

a Primary brain blood vessel endothelial cells were treated with 50 μg/ml of PBS-M or Aβ40-M derived from BMDM for 2 h. ZO-1 expression (red) in migrasome-treated endothelial cells was assessed with immunostaining and ZO-1 MFI was calculated. Data shown are representative of 3 biologically independent experiments. Data are presented as mean values ± SEM with the indicated significance (by one-way ANOVA followed by Tukey’s post-test). b Endothelial cells were seeded on top of a cell culture insert (pore diameter = 0.4 μm) as a simulation of endothelial barrier. Permeability to Fluorescein sodium (NaF) and the trans-endothelial electrical resistance (TEER) of the barrier were assessed after 2 h of migrasome treatment (50 μg/ml). Data shown are representative of 3 biologically independent experiments. Data are presented as mean values ± SEM with the indicated significance (by one-way ANOVA followed by Tukey’s post-test). c–f Healthy C57/BL6 WT mice (age = 8–10w) were treated with 4 serial doses of Raw264.7 cell derived migrasomes (10 mg/kg, i.v. injected at day 1, 2, 3, 5). Six days after the first treatment (day 7), recipients were injected with 10 mg/kg 3kDa-Dextran at 90 min before sacrifice. Mice were perfused with PBS then 4% paraformaldehyde after peripheral blood collection. c Diagram indicating the experimental time line. d Coronal brain sections of the recipients were collected and subjected to immunostaining of CD31 (green) and ZO-1 (red) to evaluate the tight junction integrity. e Leakage of 3kDa-Dextran in the brain parenchyma was assessed with fluorescent microscopy. f Fluorescent intensity of 3kDa-Dextran in the plasma and eyeballs of the recipients were assessed with a 96-well plate fluorescence reader. N = 6 in each group. Data are presented as mean values ± SEM with the indicated significance (by one-way ANOVA followed by Tukey’s post-test). Source data are provided as a Source Data file.