NGF and Alzheimer disease: In addition, in line with previous findings reporting a modulatory effect of NGF signaling on APP expression [39,107], a significant upregulation in expression of three APP isoforms of ~110 kDa, ~120 kDa, and ~130 kDa along with marked increase in the immunoreactivity level of the carboxyl-terminal CTFβ fragment of 14 kDa, are detected in primary septal neurons upon 24–48 h of neurotrophin starvation, indicating that the APP metabolism is also greatly influenced following NGF withdrawal in this novel AD-like neuronal paradigm.