title: Long-term neprilysin gene transfer is associated with reduced levels of intracellular Abeta and behavioral improvement in APP transgenic mice.
abstract: BACKGROUND
  Proteolytic degradation has emerged as a key pathway involved in controlling levels of the Alzheimer's disease (AD)-associated amyloid-beta (Abeta) peptide in the brain. The endopeptidase, neprilysin, has been implicated as a major Abeta degrading enzyme in mice and humans. Previous short and intermediate term studies have shown the potential therapeutic application of neprilysin by delivering this enzyme into the brain of APP transgenic mice using gene transfer with viral vectors. However the effects of long-term neprilysin gene transfer on other aspects of Abeta associated pathology have not been explored yet in APP transgenic mice.
  
  
  RESULTS
  We show that the sustained expression of neprilysin for up to 6 months lowered not only the amyloid plaque load but also reduced the levels of intracellular Abeta immunoreactivity. This was associated with improved behavioral performance in the water maze and ameliorated the dendritic and synaptic pathology in the APP transgenic mice.
  
  
  CONCLUSIONS
  These data support the possibility that long-term neprilysin gene therapy improves behavioral and neurodegenerative pathology by reducing intracellular Abeta.
authors.affiliation: Department of Neurosciences, University of California San Diego, La Jolla, California 92093, USA. b1spencer@ucsd.edu
authors.forename: Brian
authors.initials: B
authors.lastname: Spencer
authors.forename: Robert A
authors.initials: RA
authors.lastname: Marr
authors.forename: Edward
authors.initials: E
authors.lastname: Rockenstein
authors.forename: Leslie
authors.initials: L
authors.lastname: Crews
authors.forename: Anthony
authors.initials: A
authors.lastname: Adame
authors.forename: Rewati
authors.initials: R
authors.lastname: Potkar
authors.forename: Christina
authors.initials: C
authors.lastname: Patrick
authors.forename: Fred H
authors.initials: FH
authors.lastname: Gage
authors.forename: Inder M
authors.initials: IM
authors.lastname: Verma
authors.forename: Eliezer
authors.initials: E
authors.lastname: Masliah
mesh_terms: D000544:Alzheimer Disease / Q000235:genetics* / Q000473:pathology / Q000628:therapy*; D016229:Amyloid beta-Peptides / Q000378:metabolism*; D016564:Amyloid beta-Protein Precursor / Q000235:genetics*; D000818:Animals; D001522:Behavior, Animal; D001921:Brain / Q000378:metabolism* / Q000473:pathology; D004195:Disease Models, Animal; D015870:Gene Expression; D018014:Gene Transfer Techniques; D015316:Genetic Therapy / Q000379:methods; D006801:Humans; D007424:Intracellular Fluid / Q000378:metabolism; D016086:Lentivirus / Q000235:genetics; D018782:Maze Learning; D051379:Mice; D008822:Mice, Transgenic; D015260:Neprilysin / Q000096:biosynthesis / Q000235:genetics*; D009474:Neurons / Q000378:metabolism / Q000473:pathology; D058225:Plaque, Amyloid / Q000235:genetics / Q000473:pathology; D013995:Time
chemical_list: D016229:Amyloid beta-Peptides; D016564:Amyloid beta-Protein Precursor; D015260:Neprilysin