Significant combination of Aβ aggregation inhibitory and neuroprotective properties in silico, in vitro and in vivo by bis(propyl)-cognitin, a multifunctional anti-Alzheimer's agent

Inhibition of Aβ aggregation and neurotoxicity has been developed as an attractive therapeutic strategy to combat Alzheimer's disease (AD). Bis(propyl)-cognitin (B3C) is a multifunctional dimer derived from tacrine. Herein, the anti-aggregation and disassembly effects of B3C on Aβ, together with the neuroprotective effects and underlying mechanisms of B3C against Aβ-induced neurotoxicity were investigated in silico, in vitro and in vivo. Data from Thioflavin-T fluorescence and atomic force microscopy assays indicated that B3C (1-10 μM), but not its monomer tacrine, greatly inhibited the formation of Aβ fibrils and disaggregated pre-formed mature Aβ fibrils. Comparative molecular dynamics simulation results revealed a possible binding mode that prevented Aβ fibrils formation, showing that B3C favorably bound to Aβ via hydrophobic interactions. Additionally, B3C was able to block the neurotoxicity caused by Aβ fibrils in cultured PC12 cells. Very encouragingly, B3C (0.3 and 0.45 mg/kg) markedly alleviated the cognitive impairments in rats insulted by intra-hippocampal injection of Aβ_1-42 fibrils, more potently than tacrine (1 and 2 mg/kg). Furthermore, mechanistic studies demonstrated that B3C reversed the inhibition of phospho-GSK3β at Ser⁹ site in vitro and in vivo caused by Aβ, suggesting the neuroprotection of B3C was achieved through the inhibition of GSK3β pathway. These findings indicate that B3C could serve as an effective inhibitor of Aβ aggregation and neurotoxicity, and provide novel molecular insights into the potential application of B3C in AD prevention and treatment.