Alzheimer's disease genetic mutation evokes ultrastructural alterations: correlation to an intracellular Abeta deposition and the level of GSK-3beta-P(Y216) phosphorylated form.
Herein we demonstrate that PC12 cells, which overexpress human wild-type amyloid-beta precursor protein (AbetaPPwt) or AbetaPP bearing double Swedish mutation (AbetaPPsw), reveal phenotype characteristic for Alzheimer's disease (AD). The examination of cell ultrastructure showed the presence of peptide aggregates within the cells, activation of endosomal-lysosomal system and extensive exocytosis. Furthermore, the autophagy induction was also characteristic hallmark of amyloid-beta-induced cytotoxicity. Morphological changes were positively correlated with the extent of phosphorylated glycogen synthase kinase-3beta (phospho-Tyr(216)-GSK-3beta, GSK-3beta-P(Y216)). The activity of GSK-3beta is believed to cause tau protein hyper-phosphorylation, increased amyloid-beta production and local plaque-associated microglial-mediated inflammatory responses. All of them are symptomatic for AD. In our studies, the highly significant Y216 phosphorylation and over-expression of total GSK-3beta were observed in AbetaPPsw-transfected PC12 cells. In addition, the immuocytochemical analysis showed co-localization of GSK-3beta-P(Y216) and amyloid-beta deposits. Thus, our data support a functional role of GSK-3beta in AbetaPP processing, further implicating this kinase in the amyloid-beta-dependent pathogenesis.
Pajak
Beata
B
Department of Cell Ultrastructure, Mossakowski Medical Research Centre, Polish Academy of Sciences, Pawinskiego 5, 02-106 Warsaw, Poland. bepaj@wp.pl
Songin
Martyna
M
Strosznajder
Joanna B
JB
Gajkowska
Barbara
B
D016229:Amyloid beta-Peptides / Q000235:genetics / Q000378:metabolism*; D016564:Amyloid beta-Protein Precursor / Q000235:genetics*; D000818:Animals; D001343:Autophagy / Q000235:genetics; D004571:Electrokymography; D011992:Endosomes / Q000378:metabolism / Q000648:ultrastructure; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism*; D000071679:Glycogen Synthase Kinase 3 beta; D006801:Humans; D008247:Lysosomes / Q000378:metabolism / Q000648:ultrastructure; D016253:Microscopy, Immunoelectron / Q000379:methods; D009154:Mutation; D016716:PC12 Cells / Q000378:metabolism / Q000648:ultrastructure; D010766:Phosphorylation / Q000235:genetics; D051381:Rats; D013347:Subcellular Fractions / Q000378:metabolism; D014162:Transfection / Q000379:methods; D014443:Tyrosine / Q000235:genetics / Q000378:metabolism*
D016229:Amyloid beta-Peptides; D016564:Amyloid beta-Protein Precursor; D014443:Tyrosine; C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; C000605508:Gsk3b protein, rat; D038362:Glycogen Synthase Kinase 3