Secreted forms of beta-amyloid precursor protein protect hippocampal neurons against amyloid beta-peptide-induced oxidative injury

Exp Neurol. 1994 Jul;128(1):1-12. doi: 10.1006/exnr.1994.1107.


Alternative processing of the beta-amyloid precursor protein (beta APP) can result in liberation of either secreted forms of beta APP (APPSs), which may play roles in neuronal plasticity and survival, or amyloid beta-peptide (A beta), which can be neurotoxic. In rat hippocampal cell cultures A beta 1-40 caused a time- and concentration-dependent reduction in neuronal survival. APPS695 and APPS751 significantly reduced A beta-induced injury in a concentration-dependent manner. A beta caused an elevation of intracellular calcium levels ([Ca2+]i) which was significantly attenuated by APPSs. A beta also caused induction of reactive oxygen species (measured using the oxidation-sensitive fluorescent dye 2,7-dichlorofluorescein) which was also attenuated by APPSs. A beta-induced neurotoxicity and elevations of [Ca2+]i were attenuated by vitamin E, suggesting the involvement of free radicals in A beta-induced loss of calcium homeostasis and neuronal injury. The APPSs protected neurons against oxidative injury caused by exposure to iron. Taken together, the data indicate that A beta kills neurons by causing free radical production and increased [Ca2+]i. APPSs can protect neurons against such free radical- and Ca(2+)-mediated injury. These findings support the hypothesis that altered processing of beta APP contributes to neuronal injury in Alzheimer's disease.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amyloid beta-Peptides / toxicity*
  • Amyloid beta-Protein Precursor / metabolism
  • Amyloid beta-Protein Precursor / physiology*
  • Animals
  • Calcium / metabolism
  • Cell Survival / drug effects
  • Hippocampus / cytology
  • Hippocampus / drug effects*
  • Hippocampus / metabolism
  • Humans
  • Intracellular Membranes / metabolism
  • Neurons / drug effects*
  • Neurons / metabolism
  • Oxidants / toxicity*
  • Rats
  • Reactive Oxygen Species / metabolism


  • Amyloid beta-Peptides
  • Amyloid beta-Protein Precursor
  • Oxidants
  • Reactive Oxygen Species
  • Calcium