title: Influence of Lentiviral β-Synuclein Overexpression in the Hippocampus of a Transgenic Mouse Model of Alzheimer's Disease on Amyloid Precursor Protein Metabolism and Pathology.
abstract: BACKGROUND
  β-Synuclein (β-Syn) is a member of the highly homologous synuclein protein family. The most prominent family member, α-synuclein (α-Syn), abnormally accumulates in so-called Lewy bodies, one of the major pathological hallmarks of α-synucleinopathies. Notably, parts of the peptide backbone, called the nonamyloid component, are also found in amyloid plaques. However, β-Syn seems to have beneficial effects by reducing α-Syn aggregation, and amyloid antiaggregatory activity has been described.
  
  
  OBJECTIVE
  The aim of the study was to analyze if wild-type β-Syn can counteract functional and pathological changes in a murine Alzheimer model over different time periods.
  
  
  METHODS
  At the onset of pathology, lentiviral particles expressing human β-Syn were injected into the hippocampus of transgenic mice overexpressing human amyloid precursor protein with Swedish and London mutations (APPSL). An empty vector served as the control. Behavioral analyses were performed 1, 3 and 6 months after injection followed by biochemical and histological examinations of brain samples.
  
  
  RESULTS
  β-Syn expression was locally concentrated and rather modest, but nevertheless changed its effect on APP expression and plaque load in a time- and concentration-dependent manner. Interestingly, the phosphorylation of glycogen synthase kinase 3 beta was enhanced in APPSL mice expressing human β-Syn, but an inverse trend was observed in wild-type animals.
  
  
  CONCLUSIONS
  The initially reported beneficial effects of β-Syn could be partially reproduced, but locally elevated levels of β-Syn might also cause neurodegeneration. To enlighten the controversial pathological mechanism of β-Syn, further examinations considering the relationship between concentration and exposure time of β-Syn are needed.
authors.affiliation: Institute of Biophysics, Medical University Graz, Graz, Austria.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Krassnig
authors.forename: Cornelia
authors.initials: C
authors.lastname: Schweinzer
authors.forename: Nicole
authors.initials: N
authors.lastname: Taub
authors.forename: Daniel
authors.initials: D
authors.lastname: Havas
authors.forename: Ewald
authors.initials: E
authors.lastname: Auer
authors.forename: Stefanie
authors.initials: S
authors.lastname: Flunkert
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Schreibmayer
authors.forename: Birgit
authors.initials: B
authors.lastname: Hutter-Paier
authors.forename: Manfred
authors.initials: M
authors.lastname: Windisch
mesh_terms: D000544:Alzheimer Disease / Q000378:metabolism*; D016564:Amyloid beta-Protein Precursor / Q000378:metabolism*; D000818:Animals; D001007:Anxiety / Q000517:prevention & control; D045744:Cell Line, Tumor; D004195:Disease Models, Animal; D004660:Encephalitis / Q000378:metabolism; D005822:Genetic Vectors; D006624:Hippocampus / Q000378:metabolism*; D006801:Humans; D016086:Lentivirus; D008297:Male; D008568:Memory / Q000187:drug effects; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D051844:alpha-Synuclein / Q000378:metabolism; D051846:beta-Synuclein / Q000008:administration & dosage / Q000235:genetics / Q000378:metabolism*
chemical_list: D016564:Amyloid beta-Protein Precursor; D051844:alpha-Synuclein; D051846:beta-Synuclein; D051057:Proto-Oncogene Proteins c-akt