Fig. 3: Cellular response and cellular localization of Q32-HttEx1 fibrils prepared in the presence and absence of curcumin.

a MTT metabolic activity assay was performed following a 24, 48, and 72 h of exposure of HT22 cells with varying concentrations of HttEx1 fibrils. N = 3 independent experiments. One-way ANOVA followed by Bonferroni multiple comparisons test. Comparisons were performed against the untreated control for each incubation period. Bars represent the mean ± SD. Shading indicates protein concentration, as shown. b MTT metabolic activity assay was performed following a 72-h exposure of HT22 cells with varying concentrations of HttEx1 fibrils and HttEx1 fibrils prepared with different ratios of curcumin (as indicated. N = 3 independent experiments. One-way ANOVA followed by Dunnett’s multiple comparisons. Indicated p-values corresponding to the comparison between the untreated control and the condition in which the value is placed. Bars represent the mean ± SD. (c) Representative pictures of differentiated LUHMES cells exposed for 24 h to HttEx1 fibrcumin. Scale bars are 20 μm. d Total neurite length normalized by nuclei number. N = 1, with three experimental replicates. Shading indicates curcumin ratio, as shown. e Schematic representation of the experimental workflow for the determination of HttEx1 fibrils’ cellular localization. f Detection of HttEx1 C-terminal His-tag after post-fixing permeabilization of cells treated with HttEx1 prepared in the presence or absence of curcumin. N = 4 independent experiments. Two-way ANOVA followed by Bonferroni’s multiple comparisons test. Comparisons were performed between the non-permeabilized and permeabilized conditions for each treatment. Bars represent the mean ± SD. Schematic representations of the experiments were created using images from Servier Medical Art (Servier, http://smart.servier.com).