Abstract
Glycogen synthase kinase-3beta (GSK-3beta) is implicated in regulating apoptosis and tau protein hyperphosphorylation in Alzheimer's disease (AD). We investigated the effects of two key AD molecules, namely apoE (E3 and E4 isoforms) and beta-amyloid (Abeta) 1-42 on GSK-3beta and its major upstream regulators, intracellular calcium and protein kinases C and B (PKC and PKB) in human SH-SY5Y neuroblastoma cells. ApoE3 induced a mild, transient, Ca2+-independent and early activation of GSK-3beta. ApoE4 effects were biphasic, with an early strong GSK-3beta activation that was partially dependent on extracellular Ca2+, followed by a GSK-3beta inactivation. ApoE4 also activated PKC-alpha and PKB possibly giving the subsequent GSK-3beta inhibition. Abeta(1-42) effects were also biphasic with a strong activation dependent partially on extracellular Ca2+ followed by an inactivation. Abeta(1-42) induced an early and potent activation of PKC-alpha and a late decrease of PKB activity. ApoE4 and Abeta(1-42) were more toxic than apoE3 as shown by MTT reduction assays and generation of activated caspase-3. ApoE4 and Abeta(1-42)-induced early activation of GSK-3beta could lead to apoptosis and tau hyperphosphorylation. A late inhibition of GSK-3beta through activation of upstream kinases likely compensates the effects of apoE4 and Abeta(1-42) on GSK-3beta, the unbalanced regulation of which may contribute to AD pathology.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amyloid beta-Peptides / pharmacology*
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Apolipoprotein E3
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Apolipoprotein E4
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Apolipoproteins E / chemistry
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Apolipoproteins E / pharmacology*
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Calcium / metabolism
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Caspase 3
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Caspases / metabolism
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Cell Line, Tumor
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Cell Survival / drug effects
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Culture Media, Serum-Free / chemistry
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Cytoskeletal Proteins / metabolism
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Enzyme Activation / drug effects
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Glycogen Synthase Kinase 3 / chemistry
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Glycogen Synthase Kinase 3 / drug effects*
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Glycogen Synthase Kinase 3 / metabolism*
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Glycogen Synthase Kinase 3 beta
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Humans
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Neuroblastoma / chemistry
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Neuroblastoma / drug therapy
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Neuroblastoma / metabolism*
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Peptide Fragments / pharmacology*
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Phosphorylation / drug effects
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Protein Isoforms / chemistry
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Protein Isoforms / pharmacology
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Protein Kinase C / drug effects
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Protein Kinase C / metabolism
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Protein Kinase C-alpha
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Protein Serine-Threonine Kinases*
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Protein Transport / drug effects
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Proto-Oncogene Proteins / drug effects
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Proto-Oncogene Proteins / metabolism
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Proto-Oncogene Proteins c-akt
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Trans-Activators / metabolism
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beta Catenin
Substances
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Amyloid beta-Peptides
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Apolipoprotein E3
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Apolipoprotein E4
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Apolipoproteins E
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CTNNB1 protein, human
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Culture Media, Serum-Free
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Cytoskeletal Proteins
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Peptide Fragments
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Protein Isoforms
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Proto-Oncogene Proteins
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Trans-Activators
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amyloid beta-protein (1-42)
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beta Catenin
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GSK3B protein, human
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Glycogen Synthase Kinase 3 beta
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Protein Serine-Threonine Kinases
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Proto-Oncogene Proteins c-akt
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PRKCA protein, human
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Protein Kinase C
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Protein Kinase C-alpha
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Glycogen Synthase Kinase 3
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CASP3 protein, human
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Caspase 3
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Caspases
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Calcium