title: Chronic treatment with amyloid beta(1-42) inhibits non-cholinergic high-affinity choline transport in NG108-15 cells through protein kinase C signaling.
abstract: We investigated the influence of the amyloid-beta-peptide(1-42) on hemicholinum-3-sensitive high-affinity choline uptake in NG108-15 cells. RT-PCR analysis revealed the presence of mRNA for a choline transporter-like protein but not for cholinergic high-affinity choline transporter. Differentiation of cells increased both hemicholinum-3-sensitive choline uptake and high-affinity hemicholinium-3 binding. This transport was not influenced by tenfold excess of carnitine. Continuous presence of submicromolar concentrations of amyloid-beta-peptide(1-42) during differentiation resulted in a decrease of both choline uptake and hemicholinium-3 binding. These effects were not present when amyloid-beta-peptide(1-42) was added 5 min prior to measurements. Neither differentiation nor amyloid-beta-peptide(1-42) treatment changed levels of choline transporter-like protein mRNA. Protein kinase C inhibition by staurosporine or its inactivation by continuous presence of tetradecanoyl phorbol acetate prevented the inhibitory effect of amyloid-beta-peptide(1-42) treatment on choline uptake. Activation of protein kinase C by tetradecanoyl phorbol acetate during measurement had inhibitory effect on choline uptake in control but not amyloid-beta-peptide(1-42)-treated cells. The concentration of amyloid-beta-peptide(1-42) maximally effective on hemicholinium-3-sensitive choline uptake had no effect on cell growth, oxidative activity, membrane integrity, number of surface muscarinic receptors, caspase-3 and -8 activities, or uptake of deoxyglucose. Results demonstrate that long-term treatment with non-toxic concentrations of amyloid-beta-peptide(1-42) downregulates choline uptake presumably mediated by a choline transporter-like protein through activation of protein kinase C signaling. The decrease of choline uptake may have relevance to the pathogenesis of Alzheimer's disease.
authors.affiliation: Institute of Physiology, Czech Academy of Sciences, Department of Neurochemistry, Vídenská 1083, 14220 Prague 4, Czech Republic.
authors.forename: Jana
authors.initials: J
authors.lastname: Nováková
authors.forename: Lenka
authors.initials: L
authors.lastname: Mikasová
authors.forename: Eva
authors.initials: E
authors.lastname: Machová
authors.forename: Vĕra
authors.initials: V
authors.lastname: Lisá
authors.forename: Vladimír
authors.initials: V
authors.lastname: Dolezal
mesh_terms: D016229:Amyloid beta-Peptides / Q000008:administration & dosage / Q000502:physiology*; D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D002460:Cell Line; D018678:Cholinergic Agents / Q000494:pharmacology; D006426:Hemicholinium 3 / Q000494:pharmacology; D026901:Membrane Transport Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D009474:Neurons / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D010446:Peptide Fragments / Q000008:administration & dosage / Q000502:physiology*; D011493:Protein Kinase C / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D016229:Amyloid beta-Peptides; D018678:Cholinergic Agents; D026901:Membrane Transport Proteins; D010446:Peptide Fragments; D012333:RNA, Messenger; C075222:amyloid beta-protein (1-42); C065637:choline transporter; D006426:Hemicholinium 3; D011493:Protein Kinase C