Fig. 2
VBIT-4 improves the cognitive performance of 5 × FAD mice. a Representative LC–MS/MS analysis of VBIT-4 concentration in VBIT-4-treated mouse brain extracts [1]. Control (PBS no peak detected); (2) PLGA nano-particle-VBIT-4 administered in drinking water; (3) PLGA-VBIT-4 administered through gavage; (4) VBIT-4 in drinking water. The retention time (RT) and VBIT-4 concentration in the brain is indicated. b PK profile studied in rats following administration of VBIT-4 by IV (5 mg/kg) and PO (20 mg/kg). The observed PK parameters showed moderate-high oral bioavailability. (F 65%), T1/2 = 7.6 h, Cmax = 3310 ng/ml, Tmax = 1.33 h, AUCinf = 38,369 h*ng/ml. c Disease progression timeline in 5 × FAD mice and the experimental protocol for VBIT-4-treatment. Mice behavioral tests were performed at the age of 7–7.5 months, about 5 months after initiating VBIT-4 or control (0.36% DMSO) treatment (number of mice in each group is indicated). Effect of VBIT-4 on WT was also tested (n = 8). d, e Performance at RAWM was analyzed at trial 6 at the end of day 1, and was expressed as the number of errors (d) or time it took to reach the platform (e). For (d), a one-way ANOVA yielded a significant difference among the groups [f(3,28) = 5.4, P = 0.005], and Tukey post-hoc analysis revealed that 5 × FAD mice performed more poorly than WT (P = 0.008) and WT-VBIT-4 mice (P = 0.013). 5 × FAD-VBIT-4-treated mice performed much better than the 5 × FAD mice (P = 0.008). For (e), a one-way ANOVA yielded a significant difference among the groups [f(3,30) = 6.9, P = 0.001]. A Tukey post-hoc analysis revealed that 5 × FAD mice performed more poorly than the WT mice (P = 0.001), and the WT + VBIT-4 (P = 0.021); 5 × FAD-VBIT-4 mice performed better than 5 × FAD mice (P = 0.003). f An open field habituation test yielded a significant difference among the groups in the time they spent in a mobile state [f(3,30) = 4.5, P = 0.009]. 5 × FAD mice spent less time than WT mice, and 5 × FAD-VBIT-4 treated mice spent longer than 5 × FAD mice (P = 0.053), and similar to that of WT mice. WT-VBIT-4-treated mice (P = 0.001) spent a longer time than the WT. A one-tailed t-test revealed significantly better performance of WT than 5 × FAD mice (P = 0.013). g Number of entries in a T-maze. A one-way ANOVA yielded a significant difference among the groups [f(3,28) = 4.22, P = 0.014], Tukey post-hoc analysis revealed that 5 × FAD mice performed more poorly than WT mice (P = 0.026), and that the 5 × FAD-VBIT-4-treated mice performed better than the 5 × FAD mice (P = 0.0242). 5 × FAD-VBIT-12-treated mice performed better than 5 × FAD but less than the VBIT-4-treated mice