AKT1 and Alzheimer disease: Moreover, 1,25(OH)2D3 was shown to be neuroprotective in an in vitro model of Alzheimer’s Disease through the restoration of Aβ-induced decrease in GDNF level and activation of the phosphatidylinositol 3 kinase (PI3K)/protein kinase B (Akt)/glycogen synthase kinase-3β (GSK-3β) pathway [86].