Structure-activity relationship of GSK-3β inhibitors: insight into drug design for Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disorder characterised by cognitive impairment, memory loss, and decline in thinking and learning skills. The exact pathophysiology of the disease is still unknown; however, theories such as tau hyperphosphorylation, amyloid-β (Aβ) aggregation, and cholinergic dysfunction explain its pathogenesis. A few available drugs provide only symptomatic relief, while recently approved monoclonal antibody-based drugs target aggregated amyloid beta clearance. Extensive research is ongoing for drug development targeting various pathways, where one of the targets is glycogen synthase kinase (GSK-3β). GSK-3β plays diverse roles in physiological functions, and its dysregulation may lead to pathological conditions such as Alzheimer's disease (AD). GSK-3β comprises serine and threonine residues, is responsible for phosphorylation of the tau protein, and activates the amyloid precursor protein (APP) to synthesise Aβ. Consequently, the abnormal functioning of GSK-3β leads to hyperphosphorylation of the tau protein, and the formation of Aβ plaques eventually leads to neurofibrillary tangles. To develop GSK-3β inhibitors, one must know the requirements of crucial structural features in drug candidates to act at the active site for interaction. This review focuses on the latest pool of GSK-3β inhibitors and their design strategy, structure-activity relationship (SAR), molecular docking, and permeability across the brain layers. This broad review collection may benefit readers by providing the structural requirements to develop new GSK-3β inhibitors for treating AD.