Abstract: Objective  To explore the effect of puromycin-sensitive aminopeptidase (PSA) on  the apoptosis induced by TauP301L in SH-SY5Y cells and PC12 cells.  Methods  The proliferation and morphological changes of the cells  were detected after SH-SY5Y and PC12 cells were transfected with TauP301L for 24, 48 and 72h, respectively. The optimal time for TauP301L transfection was determined. To evaluate the effect of PSA on cell apoptosis, PC12 cells were transfected with PSA and TauP301L, and SH-SY5Y cells were transfected with PSA-siRNA and TauP301L. Cell apoptosis was determined by flow cytometry. The expression and activity of Caspase-3 were detected by Western blotting and Microplate reader, respectively. Results  TauP301L induced cells apoptosis in a time-dependent manner. After TauP301L transfection for 48h, the proliferations of SH-SY5Y and PC12 cells significantly decreased (P<0.01), while the apoptosis of the cells increased (P<0.01),as well as apoptosis-like cells could be found after Hoechst33342 staining of cell nuclei. Compared with TauP301L transfection, the expression and activity of Caspase-3 were downregulated (P<0.01), and the apoptosis decreased (P<0.01) after transfection with both PSA and TauP301L in PC12 cells. However, the expression and activity of Caspase-3 were upregulated (P<0.01) and the apoptosis increased (P<0.05) after transfection with both PSA-siRNA and TauP301L in SH-SY5Y cells. Conclusion  TauP301L can induce apoptosis in both SH-SY5Y cells and PC12 cells. PSA has a protective effect on nerve cells by inhibiting apoptosis induced by TauP301L.

Key words: Puromycin-sensitive aminopeptidase, TauP301L, Nerve cells, Caspase-3, Apoptosis