Escitalopram attenuates β-amyloid-induced tau hyperphosphorylation in primary hippocampal neurons through the 5-HT _1A receptor mediated Akt/GSK-3β pathway

Abstract

Tau hyperphosphorylation is an important pathological feature of Alzheimer's disease (AD). To investigate whether escitalopram could inhibit amyloid-β (Aβ)-induced tau hyperphosphorylation and the underlying mechanisms, we treated the rat primary hippocampal neurons with Aβ _1-42 and examined the effect of escitalopram on tau hyperphosphorylation. Results showed that escitalopram decreased Aβ _1–42-induced tau hyperphosphorylation. In addition, escitalopram activated the Akt/GSK-3β pathway, and the PI3K inhibitor LY294002 blocked the attenuation of tau hyperphosphorylation induced by escitalopram. Moreover, the 5-HT _1A receptor agonist 8-OH-DPAT also activated the Akt/GSK-3β pathway and decreased Aβ _1-42-induced tau hyperphosphorylation. Furthermore, the 5-HT _1A receptor antagonist WAY-100635 blocked the activation of Akt/GSK-3β pathway and the attenuation of tau hyperphosphorylation induced by escitalopram. Finally, escitalopram improved Aβ _1–42 induced impairment of neurite outgrowth and spine density, and reversed Aβ _1–42 induced reduction of synaptic proteins. Our results demonstrated that escitalopram attenuated Aβ _1–42-induced tau hyperphosphorylation in primary hippocampal neurons through the 5-HT _1A receptor mediated Akt/GSK-3β pathway.