BTL reduce AS aggregation and neuroinflammation in the AAV-based PD mice model.

(A). A schematic diagram illustrating the experiment to assess therapeutic efficacy: Healthy mice received unilateral AAV injection encoding human AS into the right hemisphere of the brain. Mice were injected every other day with the different treatments, i.e., free SynO4 mAbs or BTL, for two or four weeks. In the final stage, the brains were harvested, sectioned, and stained for biochemical and histological analysis and compared with the untreated PD group and healthy group (B(i), C(i)). Representative histological images of sections of the substantia nigra area after (B(i)) two weeks and (B(ii)) four weeks of treatment. Sections were stained against aggregated AS and dopaminergic neurons (scale bar: 2000 µm). (B(ii), C(ii)). The percentage of aggregated AS after (B(ii)) two weeks and (C(ii)) four weeks of different treatments. (B(iii), C(iii)). The percentage of dopaminergic neuron survival after (B(iii)) two weeks and (C(iii)) four weeks of different treatments. The healthy group values were normalized to 100%, and the values of other groups were normalized to the mean value of the healthy group. (D(i), E(i)). The number of activated microglia cells (D(i)) after two weeks and (E(i)) four weeks of different treatments; the sections were stained with an antibody against the Iba1 marker. (D(ii), E(ii)). The number of reactive astrocyte cells (D(ii)) after two weeks and (E(ii)) four weeks of different treatments; the sections were stained with an antibody against the GFAP marker. The results of B(ii), B(iii), D(i), D(ii), and E(ii) (3–4 independent repetitions in 1–3 technical replicates), C(ii) and E(i) (4–5 independent repetitions in 1–3 technical replicates) and C(iii) (3–5 independent repetitions in 1–3 technical replicates) are presented as mean±standard deviation (SD). One-way ANOVA was used for the statistical analysis in B, C, D, and E; *p≤0.0370, **p≤0.0072, ***p≤ 0.0004, ****p< 0.0001. AAV, adeno-associated virus; AS, alpha-synuclein; BTL, brain-targeted liposomes; mAbs, monoclonal antibodies; PD, Parkinson’s disease.