Fig. 6: Inhibition of oligomer release from fibrils prevents their toxicity.

a Representative confocal scanning microscope images showing the median sections of SH-SY5Y cells treated for 24 h with the indicated αS species at 0.3 μM, in the absence or presence of A11 (AHB0052, Thermo Fisher Scientific) and OC (AB2286, Sigma-Aldrich) antibodies at 1:2.5 molar ratio. Red and green fluorescence indicates the cell membranes and the αS species revealed with WGA and polyclonal anti-αS antibodies (ab52168, Abcam), respectively. The arrows in the images show the intracellular green-fluorescent punctae. b Semi-quantitative analysis of the green fluorescence signal referring to panel (a) and derived from intracellular αS species expressed as the percentage of untreated cells. c MTT reduction in SH-SY5Y cells treated for 24 h with the indicated αS species at 0.3 µM in the absence or presence of A11 and OC antibodies (1:2.5 molar ratio). d Dependence of MTT reduction (values reported in panel c) on the αS-derived fluorescence values in cells treated with OB*/SF/LF (values from panel b) in the absence or presence of A11 and OC antibodies (1:2.5 molar ratio). In all panels, experimental errors are S.E.M. (n = 4 with three internal replicates). Samples were analyzed by one-way ANOVA followed by Bonferroni’s multiple comparison test relative to untreated cells (in panels b and c, *P < 0.05, **P < 0.01, ***P < 0.001) and cells treated with the αS species (in panels b and c, ^§P < 0.05, ^§§P < 0.01, ^§§§P < 0.001). In panel d, P < 0.001. A total of 200–250 cells (a, b), and 150,000–200,000 cells (c) were analyzed per condition.