The endocannabinoid, anandamide, augments Notch-1 signaling in cultured cortical neurons exposed to amyloid-β and in the cortex of aged rats

J Biol Chem. 2012 Oct 5;287(41):34709-21. doi: 10.1074/jbc.M112.350678. Epub 2012 Aug 13.

Abstract

Aberrant Notch signaling has recently emerged as a possible mechanism for the altered neurogenesis, cognitive impairment, and learning and memory deficits associated with Alzheimer disease (AD). Recently, targeting the endocannabinoid system in models of AD has emerged as a potential approach to slow the progression of the disease process. Although studies have identified neuroprotective roles for endocannabinoids, there is a paucity of information on modulation of the pro-survival Notch pathway by endocannabinoids. In this study the influence of the endocannabinoids, anandamide (AEA) and 2-arachidonoylglycerol, on the Notch-1 pathway and on its endogenous regulators were investigated in an in vitro model of AD. We report that AEA up-regulates Notch-1 signaling in cultured neurons. We also provide evidence that although Aβ(1-42) increases expression of the endogenous inhibitor of Notch-1, numb (Nb), this can be prevented by AEA and 2-arachidonoylglycerol. Interestingly, AEA up-regulated Nct expression, a component of γ-secretase, and this was found to play a crucial role in the enhanced Notch-1 signaling mediated by AEA. The stimulatory effects of AEA on Notch-1 signaling persisted in the presence of Aβ(1-42). AEA was found to induce a preferential processing of Notch-1 over amyloid precursor protein to generate Aβ(1-40). Aging, a natural process of neurodegeneration, was associated with a reduction in Notch-1 signaling in rat cortex and hippocampus, and this was restored with chronic treatment with URB 597. In summary, AEA has the proclivity to enhance Notch-1 signaling in an in vitro model of AD, which may have relevance for restoring neurogenesis and cognition in AD.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aging / metabolism*
  • Aging / pathology
  • Alzheimer Disease / genetics
  • Alzheimer Disease / metabolism
  • Alzheimer Disease / pathology
  • Amyloid Precursor Protein Secretases / biosynthesis
  • Amyloid beta-Peptides / metabolism
  • Amyloid beta-Peptides / pharmacology*
  • Animals
  • Arachidonic Acids / metabolism*
  • Benzamides / pharmacology
  • Carbamates / pharmacology
  • Cells, Cultured
  • Cerebral Cortex / metabolism*
  • Cerebral Cortex / pathology
  • Endocannabinoids / metabolism*
  • Gene Expression Regulation, Enzymologic / drug effects
  • Glycerides / metabolism*
  • Hippocampus / metabolism
  • Hippocampus / pathology
  • Male
  • Membrane Glycoproteins / biosynthesis
  • Neurons / metabolism*
  • Neurons / pathology
  • Peptide Fragments / metabolism
  • Peptide Fragments / pharmacology*
  • Polyunsaturated Alkamides / metabolism*
  • Rats
  • Rats, Wistar
  • Receptor, Notch1 / metabolism*
  • Signal Transduction / drug effects*
  • Up-Regulation / drug effects

Substances

  • Amyloid beta-Peptides
  • Arachidonic Acids
  • Benzamides
  • Carbamates
  • Endocannabinoids
  • Glycerides
  • Membrane Glycoproteins
  • Notch1 protein, rat
  • Peptide Fragments
  • Polyunsaturated Alkamides
  • Receptor, Notch1
  • amyloid beta-protein (1-40)
  • amyloid beta-protein (1-42)
  • cyclohexyl carbamic acid 3'-carbamoylbiphenyl-3-yl ester
  • nicastrin protein
  • glyceryl 2-arachidonate
  • Amyloid Precursor Protein Secretases
  • anandamide