Synthesis and biological evaluation of 3-([1,2,4]triazolo[4,3-a]pyridin-3-yl)-4-(indol-3-yl)-maleimides as potent, selective GSK-3β inhibitors and neuroprotective agents

A series of novel 3-([1,2,4]triazolo[4,3-a]pyridin-3-yl)-4-(indol-3-yl)-maleimides were designed, prepared and evaluated for their GSK-3β inhibitory activities. Most compounds showed high potency to GSK-3β inhibition with high selectivity. Among them, compounds 7c, 7f, 7h, 7l and 7m significantly reduced GSK-3β substrate Tau phosphorylation at Ser396 in primary neurons, showing the inhibition of cellular GSK-3β. In the in vitro neuronal injury models, compounds 7c, 7f, 7h, 7l and 7m prevented neuronal death against glutamate, oxygen-glucose deprivation and nutrient serum deprivation which are associated with cerebral ischemic stroke. In the in vivo cerebral ischemia animal model, compound 7f reduced infarct size by 15% and improved the neurological deficit following focal cerebral ischemia. These findings may provide new insights into the development of novel GSK-3β inhibitors with potential neuroprotective activity.