title: ER stress is involved in Abeta-induced GSK-3beta activation and tau phosphorylation.
abstract: Intracellular neurofibrillary tangles, one of the characteristic hallmarks of Alzheimer's disease (AD), are mainly composed of hyperphosphorylated tau. The abnormal tau phosphorylation seems to be related to altered activity of kinases such as glycogen synthase kinase-3beta (GSK-3beta). Tau pathology is thought to be a later event during the progression of the disease, and it seems to occur as a consequence of amyloid-beta (Abeta) peptide accumulation. The aim of this work was to investigate whether soluble Abeta1-42, particularly oligomers that correspond to the neurotoxic species involved early in the development of AD, triggers tau phosphorylation by a mechanism involving activation of tau-kinase GSK-3beta. Several studies suggest that GSK-3beta plays a central role in signaling the downstream effects of endoplasmic reticulum (ER) stress. Therefore, the involvement of ER Ca(2+) release in GSK-3beta activation and tau phosphorylation induced by Abeta1-42 oligomers was evaluated using dantrolene, an inhibitor of Ca(2+) release through channels associated with ER ryanodine receptors. We observed that Abeta1-42 oligomers increase tau phosphorylation and compromises cell survival through a mechanism mediated by GSK-3beta activation. We also demonstrated that oligomeric Abeta1-42 induces ER stress and that ER Ca(2+) release is involved in oligomer-induced GSK-3beta activation and tau phosphorylation. This work suggests that GSK-3beta can be a promising target for therapeutic intervention in AD.
authors.affiliation: Institute of Biochemistry, Faculty of Medicine and Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.
authors.forename: Rosa
authors.initials: R
authors.lastname: Resende
authors.forename: Elisabete
authors.initials: E
authors.lastname: Ferreiro
authors.forename: Cláudia
authors.initials: C
authors.lastname: Pereira
authors.forename: Catarina Resende
authors.initials: CR
authors.lastname: Oliveira
mesh_terms: D016229:Amyloid beta-Peptides / Q000494:pharmacology*; D000818:Animals; D002478:Cells, Cultured; D004622:Embryo, Mammalian; D004721:Endoplasmic Reticulum / Q000502:physiology*; D004789:Enzyme Activation; D038362:Glycogen Synthase Kinase 3 / Q000187:drug effects / Q000378:metabolism*; D000071679:Glycogen Synthase Kinase 3 beta; D009474:Neurons / Q000166:cytology; D010446:Peptide Fragments / Q000494:pharmacology*; D010766:Phosphorylation; D051381:Rats; D016875:tau Proteins / Q000187:drug effects / Q000378:metabolism*
chemical_list: D016229:Amyloid beta-Peptides; D010446:Peptide Fragments; C075222:amyloid beta-protein (1-42); D016875:tau Proteins; D000071679:Glycogen Synthase Kinase 3 beta; C000605508:Gsk3b protein, rat; D038362:Glycogen Synthase Kinase 3