p75NTR mediates sAPPα-induced neurite outgrowth.
(A) p75NTR siRNA specifically reduced target protein expression. Cortical neurons were transfected with scrambled control or p75NTR siRNA. Cell lysates were prepared 72 h after transfection and subjected to western blotting. β-actin expression was used as an internal control. (B, C) siRNA-mediated knockdown of endogenous p75NTR suppressed sAPPα-induced neurite outgrowth. (B) Representative images of cortical neurons are displayed. Cortical neurons were transfected with scramble siRNA (control) or p75NTR siRNA. Three days after transfection, the neurons were incubated in the presence or absence of sAPPα for 24 h. Scale bar: 100 µm. (C) The mean lengths of the longest neurite per neuron were measured by image J software and represented in the graph. The graph showed the mean ± SEM from of three independent experiments. The number of neurons was 150 for each experiment. ** p<0.01, Scheffe's F test.