Pre-formed haSyn fibrils are taken up by oligodendroglial cell lines and evoke the formation of Triton-insoluble aSyn species. Representative immunoblots of Triton-, SDS-, and urea-soluble protein fractions derived from OLN-93, OLN-AS7, and OLN-p25α cells treated with 0.5 μg of haSyn PFFs for various times (24–96 h). a A small fraction of human and total aSyn (detected with 4B12 and C20 antibodies, respectively) is present in the Triton-soluble fraction of OLN-93 and OLN-AS7 (left panel) or OLN-p25α cell lysates (right panel). b, c Monomeric and high molecular weight (HMW) aSyn species (human and total) are mainly detected in the SDS- and urea-soluble fractions, following the addition of haSyn PFFs, thus representing rather insoluble aSyn species in OLN-93 and OLN-AS7 (left panel) or p25α cell lysates (right panel). Equal loading was verified by the detection of β-actin levels. Asterisk represents non-specific bands obtained with the human-specific 4B12 antibody (also detected in the PBS-treated OLN-93 or OLN-p25α cells where no human aSyn was present). d, e Quantification of monomeric and HMW species of human (upper panels) and total (lower panels) aSyn levels detected in the urea-soluble fraction of OLN-93 and OLN-AS7 cells (d) or OLN-93 and OLN-p25α cells (e) treated with 0.5 μg PFFs for 24–96 h. Data are expressed as the mean ± SE of five independent experiments with triplicate samples/condition within each experiment; *p < 0.05; **p < 0.01; ***p < 0.001, by two-way ANOVA with Bonferroni’s correction, comparing between OLN-93 and OLN-AS7 or OLN-p25α cells treated with haSyn PFFs at all time points.