Structure-based pharmacological screening, molecular docking and dynamic simulation reveals Dexketoprofen as a repurposable drug against Alzheimer's disease

Alzheimer's disease (AD) is a progressive, irreversible, neurodegenerative disease that has a profound impact on memory, reasoning, learning, and organizational abilities. Acetylcholinesterase is one of the well-established targets for managing this disease. However, the existing acetylcholinesterase inhibitors are limited in many ways. Hence, in this study, we aimed to identify potential new drugs that can be repurposed to treat AD. For this purpose, an in silico screening of drug molecules that are structural analogues of the three FDA-approved acetylcholinesterase inhibitors donepezil, rivastigmine and galantamine was performed, and 308 analogous compounds were recognized. To find the best possible drug repurposing candidates among them, an extremely rigorous filtering pipeline consisting of several drug-likeness parameters such as Lipinski, Ghose, Veber, Egan, Muegge, lead-likeness, and blood-brain barrier permeability was implemented. Finally, only 61 remained out of the 308 compounds. These 61 compounds then underwent molecular docking against the acetylcholinesterase receptor. Six compounds exhibited a higher binding affinity for the receptor compared to the FDA-approved drugs which were used as controls. Except for one compound that formed unfavorable molecular interactions, the rest were then subjected to sophisticated molecular dynamics simulation and Molecular Mechanics Poisson-Boltzmann Surface Area (MMPBSA) calculation in order to evaluate their binding properties under a simulated physiological environment. Based on all the analyses, we are suggesting Dexketoprofen, a nonsteroidal anti-inflammatory drug as the most promising candidate for repurposing against AD. Our findings will pave the way for narrowing down the list of candidates to be tested in vitro and in vivo in further studies.