Chronic treatment with amyloid beta(1-42) inhibits non-cholinergic high-affinity choline transport in NG108-15 cells through protein kinase C signaling

Brain Res. 2005 Nov 16;1062(1-2):101-10. doi: 10.1016/j.brainres.2005.09.021. Epub 2005 Oct 26.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amyloid beta-Peptides / administration & dosage
  • Amyloid beta-Peptides / physiology*
  • Animals
  • Cell Differentiation / physiology
  • Cell Line
  • Cholinergic Agents / pharmacology
  • Hemicholinium 3 / pharmacology
  • Membrane Transport Proteins / drug effects
  • Membrane Transport Proteins / genetics
  • Membrane Transport Proteins / metabolism*
  • Mice
  • Neurons / drug effects
  • Neurons / enzymology
  • Neurons / metabolism*
  • Peptide Fragments / administration & dosage
  • Peptide Fragments / physiology*
  • Protein Kinase C / metabolism*
  • RNA, Messenger / analysis
  • Rats
  • Reverse Transcriptase Polymerase Chain Reaction
  • Signal Transduction / physiology*

Substances

  • Amyloid beta-Peptides
  • Cholinergic Agents
  • Membrane Transport Proteins
  • Peptide Fragments
  • RNA, Messenger
  • amyloid beta-protein (1-42)
  • choline transporter
  • Hemicholinium 3
  • Protein Kinase C