β-asarone Protects p-tau from Okadaic Acid in PC12 Cells by Activating PP2A and Involving Akt/mTOR/Beclin-1 Pathway

Abstract

Background The aggregation of tau hyperphosphorylation (p-tau) into neurofibrillary tangles (NFT) is a hallmark in the histopathology of Alzheimer’s disease (AD). Our previous experiments found that β-asarone could prevent injury of PC12 cells induced by A 1–42, but could it fight cell damage of p-tau induced by okadaic acid (OA) is poorly understood. Objectives The emphasis of this study lies in β-asarone’s therapeutical effect on p-tau inhibition stimulated by OA. Materials and Methods 175 nmol OA was used to establish AD cells. Cell viability rate and cell toxicity were evaluated by the CCK-8 kit and LDH kit, respectively. The p-tau, Aβ42, β-secretase, and protein phosphatase 2A (PP2A) were examined by ELISA. Proteins closely related to the pathogenesis of AD are involved p-tau, Beclin-1, p-Akt, and p-mTOR were analyzed by western-blotting and immunofluorescence detection. Results The results revealed that β-asarone enhanced cell viability induced by OA in a dose-dependent manner. Moreover, compared to the OA model, p-tau, Aβ42, β-secretase, and Beclin-1 were reduced, while PP2A, p-Akt, and p-mTOR increased after treatment with β-asarone. Conclusion All data suggested that β-asarone decreased p-tau, Aβ42, and β-secretase levels, and activated PP2A levels by inhibiting Beclin-1-dependent autophagy in OA model cells, involving Akt/mTOR/Beclin-1 pathway.