800.227.0627

The N-terminal copper-binding domain of the amyloid precursor protein protects against Cu2+ neurotoxicity in vivo

Waldo F. Cerpa; María I. Barría; Marcelo A. Chacón; Miriam Suazo; Mauricio González; Carlos Opazo; Ashley I. Bush; Nibaldo C. Inestrosa;
01/15/2013
The FASEB Journal

The amyloid precursor protein (APP) contains a Cu binding domain (CuBD) localized between amino acids 135 and 156 (APP135-156), which can reduce Cu2+ to Cu1+ in vitro. The physiological function of this APP domain has not yet being established; nevertheless several studies support the notion that the CuBD of APP is involved in Cu homeostasis. We used APP synthetic peptides to evaluate their protective properties against Cu2+ neurotoxicity in a bilateral intra-hippocampal injection model. We found that human APP135-156 protects against Cu2+-induced neurotoxic effects, such as, impairment of spatial memory, neuronal cell loss, and astrogliosis. APP135-156 lacking two histidine residues showed protection against Cu 2+; however, APP135-156 mutated in cysteine 144, a key residue in the reduction of Cu2+ to Cu1+ , did not protect against Cu2+ neurotoxicity. In accordance with recent reports, the CuBD of the Caenorhabditis elegans, APL- 1, protected against Cu2+ neurotoxicity in vivo. We also found that Cu2+ neurotoxicity is associated with an increase in nitrotyrosine immunofluorescence as well as with a decrease in Cu2+ uptake. The CuBD of APP therefore may play a role in the detoxification of brain Cu.