Figure 2.

Doxycycline affects tau seeding ability and toxicity. (A) Effect of doxycycline on the seeding capability of pre-aggregated tau species. Pre-incubated tau species were obtained by incubating a tau:heparin solution (tau 22 μM; 0.2 mg/ml heparin) 24 h at 37°C under orbital agitation. 25 μl aliquots of this solution were used as seeds and added to fresh monomeric tau (22 μM) in the absence or presence of doxycycline 100 μM and incubated 0 h, 48 h and 168 h at 37°C under orbital agitation. (B) SH-SY5Y cells were treated with aggregated species of tau incubated in the presence of heparin, with or without doxycycline, and harvested after 16 h of incubation. Viability was measured using an MTT assay and expressed as a percentage relative to the untreated cells. Statistical analyses for both experiments were performed using the ANOVA test. n = 3 ns: not significant. ****p ≤ 0.0001. Error bars represent SD.