Neuroprotective effects of linarin through activation of the PI3K/Akt pathway in amyloid-β-induced neuronal cell death

Linarin, a natural occurring flavanol glycoside derived from Mentha arvensis and Buddleja davidii is known to have anti-acetylcholinesterase effects. The present study intended to explore the neuroprotective effects of linarin against Aβ25–35-induced neurotoxicity with cultured rat pheochromocytoma cells (PC12 cells) and the possible mechanisms involved. For this purpose, PC12 cells were cultured and exposed to 30 μM Aβ25–35 in the absence or presence of linarin (0.1, 1.0 and 10 μM). In addition, the potential contribution of the PI3K/Akt neuroprotective pathway in linarin-mediated protection against Aβ25–35-induced neurotoxicity was also investigated. The results showed that linarin dose-dependently increased cell viability and reduced the number of apoptotic cells as measured by MTT assay, Annexin-V/PI staining, JC-1 staining and caspase-3 activity assay. Linarin could also inhibit acetylcholinesterase activity induced by Aβ25–35 in PC12 cells. Further study revealed that linarin induced the phosphorylation of Akt dose-dependently. Treatment of PC12 cells with the PI3K inhibitor LY294002 attenuated the protective effects of linarin. Furthermore, linarin also stimulated phosphorylation of glycogen synthase kinase-3β (GSK-3β), a downstream target of PI3K/Akt. Moreover, the expression of the anti-apoptotic protein Bcl-2 was also increased by linarin treatment. These results suggest that linarin prevents Aβ25–35-induced neurotoxicity through the activation of PI3K/Akt, which subsequently inhibits GSK-3β and up-regulates Bcl-2. These findings raise the possibility that linarin may be a potent therapeutic compound against Alzheimer’s disease acting through both acetylcholinesterase inhibition and neuroprotection.

Linarin is a natural acetylcholinesterase inhibitor and the present study explored the neuroprotective effects against Aβ25–35-induced neurotoxicity in cultured rat pheochromocytoma cells and the possible mechanisms involved.Figure optionsDownload as PowerPoint slide