Figure 6

The availability of cysteines drastically influences the trans-propagation of tau. (a) CHO_K1 cells expressing either tau E14 or tau E14 C291/322A were co-cultured with FGF2-GFP cells for 48 h and were subsequently stained for tau, FGF2, and nucleus using antibodies against HA, GFP, and the Hoechst dye, respectively (scale bars, 10 µm and 3 µm for the magnified image). (b) The tau-positive signal inside FGF2-GFP cells was quantified through an image-based analysis (3 independent biological replicates with at least 400 processed cells per case). The data represent mean values ± s.d. and were statistically analysed through one-way ANOVA followed by Tukey’s post hoc analysis. (c) CHO_K1 RD-GFP cells were co-cultured with CHO_K1 tau E14, CHO₇₄₅ tau E14, and CHO_K1 tau E14 C291/322A cells. All combinations were stained with tau10 and GFP antibodies for full-length tau and RD-GFP detection, respectively. Hoechst dye was used for nuclear staining. Scale bars correspond to 15 µm and 5 µm for the original and magnified images, respectively. (d) The RD-GFP positive inclusions were quantified through a semi-automated image analysis of randomly selected z-projected scans and the number of inclusions/cell for each condition was compared to the CHO_K1 tau E14-CHO_K1 RD-GFP co-culture combination (3 independent biological replicates with at least 330 processed cells per case). The data represent mean values ± SEM and were statistically analysed through one-way ANOVA followed by Tukey’s post hoc analysis.