title: Cell-line specific protection by berry polyphenols against hydrogen peroxide challenge and lack of effect on metabolism of amyloid precursor protein.
abstract: Amyloid precursor protein (APP) altered metabolism, Aβ-overproduction/aggregation and oxidative stress are implicated in the development of Alzheimer's disease pathology. Based on our previous data indicating that administration of a polyphenol-rich (PrB) blueberry extract (from wild Vaccinium angustifolium) is memory enhancing in healthy mice and in order to delineate the neuroprotective mechanisms, this study investigated the antioxidant effects of PrB in H₂O₂-induced oxidative damage, Aβ peptide fibrillogenesis and APP metabolism. PrB suppressed H₂O₂-initiated oxidation (DCF assay) and cell death (MTT assay) in SH-SY5Y cells. Protective effects were observed on Chinese hamster ovary (CHO) cells overexpressing APP770 carrying the mutation Val717Phe only at high concentrations, while further damage on HEK293 cells was induced after co-treatment with 250 µM H₂O₂ and PrB in comparison with H₂O₂ alone. Using the thioflavine T assay, blueberry polyphenols inhibited Aβ-aggregation (~70%, 15 µg/mL) in a time-dependent manner, while in the CHO(APP770) cells it had no effect on APP metabolism as assessed by western blot. The results suggest that blueberry polyphenols exhibit antioxidant and/or pro-oxidant properties according to the cellular environment and have no effect on APP metabolism.
authors.affiliation: Laboratory of Human and Animal Physiology, Department of Biology, University of Patras, Greece.
authors.forename: Magdalini A
authors.initials: MA
authors.lastname: Papandreou
authors.forename: Maria
authors.initials: M
authors.lastname: Tsachaki
authors.forename: Spiros
authors.initials: S
authors.lastname: Efthimiopoulos
authors.forename: Dorothy
authors.initials: D
authors.lastname: Klimis-Zacas
authors.forename: Marigoula
authors.initials: M
authors.lastname: Margarity
authors.forename: Fotini N
authors.initials: FN
authors.lastname: Lamari
mesh_terms: D016564:Amyloid beta-Protein Precursor / Q000378:metabolism*; D000818:Animals; D000872:Anthocyanins / Q000494:pharmacology; D029798:Blueberry Plants / Q000737:chemistry*; D016466:CHO Cells; D002470:Cell Survival; D006224:Cricetinae; D005638:Fruit / Q000737:chemistry; D057809:HEK293 Cells; D006801:Humans; D006861:Hydrogen Peroxide / Q000633:toxicity*; D018384:Oxidative Stress; D010936:Plant Extracts / Q000494:pharmacology; D059808:Polyphenols / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000032:analysis
chemical_list: D016564:Amyloid beta-Protein Precursor; D000872:Anthocyanins; D010936:Plant Extracts; D059808:Polyphenols; D017382:Reactive Oxygen Species; D006861:Hydrogen Peroxide