A cellular model of Alzheimer's disease therapeutic efficacy: PKC activation reverses Abeta-induced biomarker abnormality on cultured fibroblasts

Neurobiol Dis. 2009 May;34(2):332-9. doi: 10.1016/j.nbd.2009.02.003. Epub 2009 Feb 20.

Abstract

PKC signaling is critical for the non-toxic degradation of amyloid precursor protein (APP) and inhibition of GSK3beta, which controls phosphorylation of tau protein in Alzheimer's disease (AD). Thus the misregulation of PKC signaling could contribute to the origins of AD. Bryostatin, a potent PKC modulator, has the potential to ameliorate both the neurodegeneration and the recent memory loss associated with AD. As reported herein bryostatin and a potent synthetic analog (picolog) are found to cause stimulation of non-amyloidogenic pathways by increasing alpha-secretase activity and thus lowering the amount of toxic Abeta produced. Both bryostatin and picolog increased the secretion of the alpha-secretase product (s-APP-alpha) of APP at sub-nanomolar to nanomolar concentrations. A peripheral AD-Biomarker has previously been autopsy-validated. This Biomarker, based on bradykinin-induced differential phosphorylation of Erk1 and Erk2, has been used here to test the therapeutic efficacy both for bryostatin and picolog. Both of these PKC activators are then shown to convert the AD Erk1/2 phenotype of fibroblasts into the phenotype of "normal" control skin fibroblasts. This conversion occurred for both the abnormal Erk1/2 phenotype induced by application of Abeta(1-42) to the fibroblasts or the phenotype observed for fibroblasts of AD patients. The Abeta(1-42)-induction, and PKC modulator reversal of the AD Erk1/2 biomarker phenotype demonstrate the AD-Biomarker's potential to monitor both disease progression and treatment response. Additionally, this first demonstration of the therapeutic potential in AD of a synthetically accessible bryostatin analog warrants further preclinical advancement.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alzheimer Disease / drug therapy*
  • Alzheimer Disease / metabolism
  • Alzheimer Disease / physiopathology
  • Amyloid Precursor Protein Secretases / drug effects
  • Amyloid Precursor Protein Secretases / metabolism
  • Amyloid beta-Peptides / drug effects
  • Amyloid beta-Peptides / metabolism*
  • Biomarkers / analysis
  • Biomarkers / metabolism
  • Bradykinin / pharmacology
  • Bryostatins / pharmacology*
  • Bryostatins / therapeutic use
  • Cell Differentiation / drug effects
  • Cell Differentiation / physiology
  • Cells, Cultured
  • Dose-Response Relationship, Drug
  • Drug Evaluation, Preclinical / methods*
  • Enzyme Activation / drug effects
  • Enzyme Activation / physiology
  • Extracellular Signal-Regulated MAP Kinases / drug effects
  • Extracellular Signal-Regulated MAP Kinases / metabolism
  • Fibroblasts / drug effects
  • Fibroblasts / metabolism
  • Humans
  • Models, Biological*
  • Neuroprotective Agents / pharmacology
  • Neuroprotective Agents / therapeutic use
  • Peptide Fragments / drug effects
  • Peptide Fragments / metabolism
  • Phenotype
  • Phosphorylation / drug effects
  • Protein Kinase C / drug effects*
  • Protein Kinase C / metabolism

Substances

  • Amyloid beta-Peptides
  • Biomarkers
  • Bryostatins
  • Neuroprotective Agents
  • Peptide Fragments
  • amyloid beta-protein (1-42)
  • Protein Kinase C
  • Extracellular Signal-Regulated MAP Kinases
  • Amyloid Precursor Protein Secretases
  • Bradykinin