title: A human prion protein peptide (PrP(59-91)) protects against copper neurotoxicity.
abstract: Human cellular prion protein (PrP(C)) is involved in several neurodegenerative disorders; however, its normal function is unknown. We report here that a synthetic peptide corresponding to the four-octarepeat sequence of the PrP(C) (PrP(59-91)) protects hippocampal neurons against copper neurotoxic effects in vivo. Using a rat bilateral intrahippocampal injection model, we found that PrP(59-91) protects against copper-induced neurotoxicity, including a recovery in spatial learning performance and a reduced neuronal cell loss and astrogliosis. Previous studies from our laboratory indicated that a tryptophan (Trp) residue plays a key role in the reduction of copper(II) to copper(I); therefore several PrP(59-91) fragments lacking histidine (His) and Trp residues were tested for their capacity to protect from copper toxicity. A PrP(59-91) peptide lacking His residue shows as much neuroprotection as the native peptide; however, PrP(59-91) without Trp residues only partially protected against copper toxicity. The neuroprotective effect not only occurs with PrP(59-91), in fact a full neuroprotection was also observed using just one octamer of the N-terminal region of prion protein. We conclude that the N-terminal tandem octarepeat of the human PrP(C) protects neurons against copper toxicity by a differential contribution of the binding (His) and reducing (Trp) copper activities of PrP(59-91). Our results are consistent with the idea that PrP(C) function is related to copper homeostasis.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000473:pathology; D003300:Copper / Q000633:toxicity*; D006624:Hippocampus / Q000187:drug effects / Q000473:pathology / Q000502:physiology; D007276:Injections, Intraventricular; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D008568:Memory / Q000187:drug effects*; D008969:Molecular Sequence Data; D009498:Neurotoxins / Q000494:pharmacology; D010446:Peptide Fragments / Q000737:chemistry / Q000494:pharmacology*; D011328:Prions / Q000737:chemistry / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013028:Space Perception / Q000187:drug effects*
chemical_list: D009498:Neurotoxins; D010446:Peptide Fragments; D011328:Prions; C474324:prion protein (59-91); D003300:Copper