Fig. 2: Ageing and thyroidectomy increased exosomal transport of liver-derived ApoE4 into the brain.

A Experimental design: adult and old mice were injected with lenti-Arg1-ApoE4-eGFP vector through hepatic portal veins; 2 months-old mice were randomly operated sham or thyroidectomy. Four weeks after surgery mice were injected lenti-Arg1-ApoE4-eGFP vector through hepatic portal veins. B Injection of lentivirus vectors of h-ApoE4 and Arg1 (Lenti-Arg1-ApoE4-eGFP) through hepatic portal vein. C Immunofluoresence images taken from liver tissue of h-ApoE4 (green) and Arg1 (red) with nucleus marker DAPI (blue) performed 3 days after injection of lenti-Arg1-ApoE4-eGFP or lentivirus negative control vectors in adult mice. Scale bar = 50 μm. D Electron microscope images of exosome extracted from liver and serum (left), and the representative Western blots for h-ApoE4 in exosomes extracted from liver and blood serum (right). E Relative expression ratio of h-ApoE4 and GAPDH is plotted as mean ± SD, n = 6. One-way ANOVA for comparisons including more than two groups; unpaired two-tailed t-test for two-group comparisons. Compared to adult group, *p < 0.05, **p < 0.01, ***p < 0.001. F Immunofluorescence images of h-ApoE4 (green) co-stained with AQP1 (red) and DAP1 (blue) in choroid plexus. Scale bar = 50 μm. G Immunofluorescence images of h-ApoE4 (green) co-stained with AQP1 (red) and DAP1 (blue) in the whole cortex and hippocampus. Scale bar = 50 μm. H Immunofluorescence intensity of h-ApoE4 normalised to adult group. The normalised intensity is plotted as mean ± SD, n = 6. One-way ANOVA for comparisons including more than two groups; unpaired two-tailed t-test for two-group comparisons. One-way ANOVA for comparisons including more than two groups; unpaired two-tailed t-test for twogroup comparisons. Compared to adult group, *p < 0.05, **p < 0.01, ***p < 0.001.