The impact of capsaicinoids on APP processing in Alzheimer's disease in SH-SY5Y cells

Sci Rep. 2020 Jun 8;10(1):9164. doi: 10.1038/s41598-020-66009-6.

Abstract

The vanilloid capsaicin is a widely consumed spice, known for its burning and "hot" sensation through activation of TRPV1 ion-channels, but also known to decrease oxidative stress, inflammation and influence tau-pathology. Beside these positive effects, little is known about its effects on amyloid-precursor-protein (APP) processing leading to amyloid-β (Aβ), the major component of senile plaques. Treatment of neuroblastoma cells with capsaicinoids (24 hours, 10 µM) resulted in enhanced Aβ-production and reduced Aβ-degradation, leading to increased Aβ-levels. In detailed analysis of the amyloidogenic-pathway, both BACE1 gene-expression as well as protein-levels were found to be elevated, leading to increased β-secretase-activity. Additionally, γ-secretase gene-expression as well as activity was enhanced, accompanied by a shift of presenilin from non-raft to raft membrane-domains where amyloidogenic processing takes place. Furthermore, impaired Aβ-degradation in presence of capsaicinoids is dependent on the insulin-degrading-enzyme, one of the major Aβ-degrading-enzymes. Regarding Aβ-homeostasis, no differences were found between the major capsaicinoids, capsaicin and dihydrocapsaicin, and a mixture of naturally derived capsaicinoids; effects on Ca2+-homeostasis were ruled out. Our results show that in respect to Alzheimer's disease, besides the known positive effects of capsaicinoids, pro-amyloidogenic properties also exist, enhancing Aβ-levels, likely restricting the potential use of capsaicinoids as therapeutic substances in Alzheimer's disease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alzheimer Disease / etiology
  • Alzheimer Disease / metabolism*
  • Amyloid Precursor Protein Secretases / genetics
  • Amyloid Precursor Protein Secretases / metabolism
  • Amyloid beta-Peptides / metabolism*
  • Amyloid beta-Protein Precursor / metabolism*
  • Aspartic Acid Endopeptidases / genetics
  • Aspartic Acid Endopeptidases / metabolism
  • Capsaicin / adverse effects*
  • Cell Line, Tumor
  • Contraindications, Drug
  • Gene Expression
  • Humans
  • Neuroblastoma

Substances

  • Amyloid beta-Peptides
  • Amyloid beta-Protein Precursor
  • Amyloid Precursor Protein Secretases
  • Aspartic Acid Endopeptidases
  • BACE1 protein, human
  • Capsaicin