Combining an amyloid-beta (Aβ) cleaving enzyme inhibitor with a γ-secretase modulator results in an additive reduction of Aβ production

FEBS J. 2015 Jan;282(1):65-73. doi: 10.1111/febs.13103. Epub 2014 Nov 7.


A major hallmark of Alzheimer's disease (AD) is the deposition of amyloid-β (Aβ) peptides in amyloid plaques. Aβ peptides are produced by sequential cleavage of the amyloid precursor protein by the β amyloid cleaving enzyme (BACE) and the γ-secretase (γ-sec) complex. Pharmacological treatments that decrease brain levels of in particular the toxic Aβ42 peptide are thought to be promising approaches for AD disease modification. Potent and selective BACE1 inhibitors as well as γ-sec modulators (GSMs) have been designed. Pharmacological intervention of secretase function is not without risks of either on- or off-target adverse effects. One way of improving the therapeutic window could be to combine treatment on multiple targets, using smaller individual doses and thereby minimizing adverse effect liability. We show that combined treatment of primary cortical neurons with a BACE1 inhibitor and a GSM gives an additive effect on Aβ42 level change compared with the individual treatments. We extend this finding to C57BL/6 mice, where the combined treatment results in reduction of brain Aβ42 levels reflecting the sum of the individual treatment efficacies. These results show that pharmacological targeting of two amyloid precursor protein processing steps is feasible without negatively interfering with the mechanism of action on individual targets. We conclude that targeting Aβ production by combining a BACE inhibitor and a GSM could be a viable approach for therapeutic intervention in AD modification.

Keywords: Alzheimer's disease; amyloid beta peptides; beta amyloid cleaving enzyme; gamma-secretase complex.

MeSH terms

  • Alzheimer Disease / drug therapy
  • Alzheimer Disease / metabolism
  • Amyloid Precursor Protein Secretases / antagonists & inhibitors*
  • Amyloid Precursor Protein Secretases / metabolism*
  • Amyloid beta-Peptides / biosynthesis
  • Amyloid beta-Peptides / metabolism*
  • Animals
  • Aspartic Acid Endopeptidases / antagonists & inhibitors
  • Aspartic Acid Endopeptidases / metabolism
  • Brain / drug effects
  • Brain / metabolism
  • Drug Synergism
  • Female
  • HEK293 Cells
  • Humans
  • Mice
  • Mice, Inbred C57BL
  • Peptide Fragments / metabolism
  • Protease Inhibitors / administration & dosage
  • Protease Inhibitors / pharmacology
  • Pyrans / administration & dosage
  • Pyrans / pharmacology
  • Pyrimidines / administration & dosage
  • Pyrimidines / pharmacology


  • AZ4800
  • Amyloid beta-Peptides
  • Peptide Fragments
  • Protease Inhibitors
  • Pyrans
  • Pyrimidines
  • amyloid beta-protein (1-42)
  • Amyloid Precursor Protein Secretases
  • Aspartic Acid Endopeptidases
  • BACE1 protein, human