Aβ31-35-induced neuronal apoptosis is mediated by JNK-dependent extrinsic apoptosis pathway

Objective To investigate whether JNK-caspase-dependent apoptotic pathway is involved in A beta(31-35)-induced apoptosis of cultured cortical neurons. Methods Cultured cortical neurons were treated with A beta(31-35) (25 mu mol/L) for 4 h, 8 h, 16 h and 24 h, respectively. Caspase activities were measured using a spectrophotometer. Levels of c-Jun phosphorylation (p-c-Jun) and Fas ligand (FasL) expression were assessed by immunocytochemistry method and quantified using Image-pro plus11.0 image processing and analysis software. Results Treatment with A beta(31-35) (25 mu mol/L) for 24 h induced significant increases in the activities of caspase-3 and caspase-8 in the cortical neurons. Besides, A beta(31-35) could time-dependently enhance the expression of p-c-Jun protein. Moreover, SP600125 application (100 nmol/L) could completely abolish A beta(31-35) neurotoxicity. The increase in FasL expression was detected at 8 h, 16 h and 24 h after A beta(31-35) treatment, and SP600125 (100 nmol/L) significantly inhibited FasL expression. Conclusion JNK-c-Jun-FasL-caspase-dependent extrinsic apoptotic pathway plays a critical role in mediating A beta(31-35)-induced apoptosis of cultured neurons.