Effect of β-secretase inhibitor on amyloid protein precursor metabolism in okadaic acid-induced PC12 cells / 中华神经医学杂志

ABSTRACT

Objective To observe the effect of β-secretase inhibitor on amyloid protein precursor (APP) metabolism in okadaic acid (OA)-induced PC12 cells. Methods PC12 cells were pretreated with β-secretase inhibitor followed 30 min later by treatment with 10 nmol/L OA for 4, 8, 16, 24 or 48 h to induce tau phosphorylation. The viability of the PC12 cells was measured by MTT assay, and APP metabolism in the cells was examined by immunocytochemistry and Western blotting with specific antibodies against the APP-N-terminus (NT) and APP-C-terminus (CT). Results OA at the concentration of 10 nmol/L time-dependently inhibited PC12 cell viability, and this effect was obviously attenuated by pretreatment of the cells with β-secretase inhibitor. After OA treatment, both APP and β-C-terminal fragment (βCTF) were significantly increased in PC12 cells, and pretreatment with β-secretase inhibitor further increased the intracellular APP level and reduced the level of βCTF. Conclusion OA treatment causes a shift in APP metabolism to the β-secretase pathway that produces neurotoxic βCTF in PC12 cells. Inhibition of β-secretase may alleviate OA-induced cytotoxicity by decreasing the level of βCTF, but the application of β-secretase inhibitor may further increase APP level in the cells.