Dimeric bis (heptyl)-Cognitin Blocks Alzheimer's β-Amyloid Neurotoxicity Via the Inhibition of Aβ Fibrils Formation and Disaggregation of Preformed Fibrils.
OBJECTIVE
Fibrillar aggregates of β-amyloid protein (Aβ) are the main constituent of senile plaques and considered to be one of the causative events in the pathogenesis of Alzheimer's disease (AD). Compounds that could inhibit Aβ fibrils formation, disaggregate preformed Aβ fibrils as well as reduce their associated neurotoxicity might have therapeutic values for treating AD. In this study, the inhibitory effects of bis (heptyl)-cognitin (B7C), a multifunctional dimer derived from tacrine, on aggregation and neurotoxicity of Aβ1-40 were evaluated both in vitro and in vivo.


METHODS
Thioflavin T fluorescence assay was carried out to evaluate Aβ aggregation, MTT and Hoechst-staining assays were performed to investigate Aβ-associated neurotoxicity. Fluorescent probe DCFH-DA was used to estimate the accumulation of intracellular reactive oxygen stress (ROS). Morris water maze was applied to determine learning and memory deficits induced by intracerebroventricular infusion of Aβ in rats.


RESULTS
B7C (0.1-10 μM), but not tacrine, effectively inhibited Aβ fibrils formation and disaggregated preformed Aβ fibrils following co-incubation of B7C and Aβ monomers or preformed fibrils, respectively. In addition, B7C markedly reduced Aβ fibrils-associated neurotoxicity in SH-SY5Y cell line, as evidenced by the increase in cell survival, the decrease in Hoechst-stained nuclei and in intracellular ROS. Most encouragingly, B7C (0.1 and 0.2 mg/kg), 10 times more potently than tacrine (1 and 2 mg/kg), inhibited memory impairments after intracerebroventricular infusion of Aβ in rats, as evidenced by the decrease in escape latency and the increase in the spatial bias in Morris water maze test along with upregulation of choline acetyltransferase activity and downregulation of acetylcholinesterase activity.


CONCLUSIONS
These findings provide not only novel molecular insight into the potential application of B7C in treating AD, but also an effective approach for screening anti-AD agents.
Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, China.|The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen, China.
Sheng-Quan
SQ
Hu
Department of Pharmaceutical Science, School of Pharmacy, Shanghai Key Laboratory of New Drug Design, East China University of Science and Technology, Shanghai, China.
Rui
R
Wang
Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, China.|The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen, China.
Wei
W
Cui
Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, China.|The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen, China.
Shing-Hung
SH
Mak
National Engineering Laboratory for Modern Silk, College of Textile and Clothing Engineering, Soochow University, Suzhou, China.
Gang
G
Li
State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau, China.
Yuan-Jia
YJ
Hu
State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau, China.
Ming-Yuen
MY
Lee
Computer-Aided Molecular Design Laboratory, Mayo Clinic, Rochester, MN, USA.
Yuan-Ping
YP
Pang
Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, China.|The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen, China.
Yi-Fan
YF
Han
D000544:Alzheimer Disease / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology; D000682:Amyloid / Q000187:drug effects* / Q000378:metabolism; D016229:Amyloid beta-Peptides / Q000633:toxicity*; D000818:Animals; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical; D006801:Humans; D008297:Male; D018782:Maze Learning / Q000187:drug effects / Q000502:physiology; D008569:Memory Disorders / Q000188:drug therapy / Q000503:physiopathology; D018696:Neuroprotective Agents / Q000737:chemistry / Q000494:pharmacology*; D010446:Peptide Fragments / Q000633:toxicity*; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D013619:Tacrine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology
D000682:Amyloid; D016229:Amyloid beta-Peptides; D018696:Neuroprotective Agents; D010446:Peptide Fragments; D017382:Reactive Oxygen Species; C078592:amyloid beta-protein (1-40); C000609450:bis(heptyl)cognitin; D013619:Tacrine
Alzheimer's disease; Aβ fibrils; Bis (heptyl)-cognitin; Morris water maze; Reactive oxygen stress; Thioflavin T