Kinase experiment:

Tau aggregation is monitored using thioflavin T. The test compound (PE859), 10 μM 3RMBD and 10 μM heparin are dissolved in 50 mM Tris-HCl (pH7.6), and incubated at 37℃ up to 144 hours. At each point of incubation time, 135 μL of the solutions are removed and mixed with 15 μL of 100 μM ThT solution (final concentration: 10 μM) and the fluorescence intensity with excitation at 440 nm and emission at 486 nm is measured[2].

Animal experiment:

Mice: PE859 is dissolved in 80% PEG400 and 20% water solution at 5 mg/mL, and orally-administered at a dose of 40 mg/kg/day for 6 months (from 9 to 15 months of age). The body weights of the mice are measured once a week during PE859 treatment[2].

PE859 is a potent inhibitor of both tau and Aβ aggregation with IC50 values of 0.66 and 1.2 μM, respectively.

PE859 inhibits the heparin-induced aggregation of both 3RMBD and full length tau in a concentration-dependent manner. In each assay, the IC50 values calculated at the last measurement periods are 0.81 μM, and 2.23 μM, respectively. PE859 inhibits tau aggregation through formation of beta-sheet structure[2].

PE859 could cross the blood-brain barrier and that PE859 could be distributed into the tissues of the central nervous system. The maximum concentration of PE859 is 2.005 μg/mL in the blood at 3 h and 1.428 μg/g in the brain at 6 h. PE859 delays onset and progression of the motor dysfunction in JNPL3 mice. PE859 delays progression of the motor dysfunction through the inhibition of accumulation of sarkosyl-insoluble tau. [2]

[1]. Okuda M, et al. Design and synthesis of curcumin derivatives as tau and amyloid β dual aggregation inhibitors. Bioorg Med Chem Lett. 2016 Oct 15;26(20):5024-5028. [2]. Okuda M, et al. PE859, a novel tau aggregation inhibitor, reduces aggregated tau and prevents onset and progression of neural dysfunction in vivo. PLoS One. 2015 Feb 6;10(2):e0117511.