Computational Drug Repurposing For The Identification Of Novel AchE Inhibtiors

Cognition and memory impairment are hallmarks of the pathological cascade of various neurodegenerative disorders such as Alzheimer’s disease, Parkinson’s disease, and Huntington’s disease. However, to the best of our knowledge, only four approved small-molecule therapeutics are on the market, of which three are acetylcholinesterase (AchE) inhibitors (donepezil, rivastigmine and galanthamine), for the treatment of mild to moderate AD symptoms. Unfortunately, none of these drugs can alter the course of AD progression. Our goal is to achieve novel AchE inhibitors with tolerable side effects to benefit order patients with neurodegenerative orders.In this study, we developed a novel computational strategy with two-dimensional virtual screening for not only affinity but also specificity. We integrated the two-dimensional virtual screening with ligand screening for 3D shape, electrostatic similarity and local binding site similarity to find existing drugs that may reduce the signs of cognitive deficits. Based on the results of virtual screening, we choose thirteen TKIs to perform in vitro AchE enzymatic assay and pazopanib stands out as the most potent molecule. We evaluated and compared the effects of intragastrically-administered pazopanib with donepezil, a marketed AchE inhibitor, in cognitive and behavioral assays including the novel object recognition test, Y maze and Morris water maze test. Our specific conclusions are as follow:(1) Based on the results of two-dimensional virtual screening with ligand screening for 3D shape, electrostatic similarity, we found 3 TKIs have similar ISR values and molecular property with Donepezil. The three TKIs are sunitinib, sorafinib and pazopanib.(2) The results of local binding site similarity suggests that the majority of top ranked protein belong to the protein kinase family and the majority belong to the tyrosine kinase family. This result is correlated with the virtual screening of FDA approved small molecules.(3) The results of in vitro AchE enzymatic assay confirmed that our novel virtual screening staregy is practical and valuable. For the first time, we found that pazopanib and sunitinib, two tyrosine kinase inhibitors marketed for cancer treatment, inhibits acetylcholinesterase (AchE) activities at 0.93μM and 5.87μM respectively.(4) Our in vivo experiments suggested that pazopanib can restore memory loss and cognitive dysfunction to a similar extent as donepezil in a dosage of 15 mg/kg, only one fifth of the equivalent clinical dosage for cancer treatment. Furthermore, we demonstrated that pazopanib dramatically enhances the hippocampal Ach levels and increases the expression of the synaptic marker SYP.The present study which coupled the computer virtual screening techniques and biological experiments suggested that pazopanib may become a viable treatment option for memory and cognitive deficits with a good safety profile in humans.