Identification of neurotoxic cytokines by profiling Alzheimer's disease tissues and neuron culture viability screening

Sci Rep. 2015 Nov 13:5:16622. doi: 10.1038/srep16622.

Abstract

Alzheimer's disease (AD) therapeutics based on the amyloid hypothesis have shown minimal efficacy in patients, suggesting that the activity of amyloid beta (Aβ) represents only one aspect of AD pathogenesis. Since neuroinflammation is thought to play an important role in AD, we hypothesized that cytokines may play a direct role in promoting neuronal death. Here, we profiled cytokine expression in a small cohort of human AD and control brain tissues. We identified AD-associated cytokines using partial least squares regression to correlate cytokine expression with quantified pathologic disease state and then used neuron cultures to test whether cytokines up-regulated in AD tissues could affect neuronal viability. This analysis identified cytokines that were associated with the pathological severity. Of the top correlates, only TNF-α reduced viability in neuron culture when applied alone. VEGF also reduced viability when applied together with Aβ, which was surprising because VEGF has been viewed as a neuro-protective protein. We found that this synthetic pro-death effect of VEGF in the context of Aβ was commensurate with VEGFR-dependent changes in multiple signaling pathways that govern cell fate. Our findings suggest that profiling of tissues combined with a culture-based screening approach can successfully identify new mechanisms driving neuronal death.

Publication types

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

MeSH terms

  • Aged
  • Aged, 80 and over
  • Alzheimer Disease / genetics
  • Alzheimer Disease / metabolism*
  • Amyloid beta-Peptides / metabolism
  • Amyloid beta-Peptides / pharmacology
  • Brain / metabolism
  • Cell Survival / drug effects
  • Cell Survival / genetics
  • Cells, Cultured
  • Cytokines / genetics
  • Cytokines / metabolism*
  • Cytokines / pharmacology
  • Female
  • Gene Expression Profiling / methods
  • Gene Regulatory Networks / genetics
  • Humans
  • Inflammation Mediators / metabolism*
  • Inflammation Mediators / pharmacology
  • Interleukin-5 / genetics
  • Interleukin-5 / metabolism
  • Interleukin-5 / pharmacology
  • Least-Squares Analysis
  • Male
  • Middle Aged
  • Multivariate Analysis
  • Neurons / drug effects
  • Neurons / metabolism*
  • Regression Analysis
  • Tumor Necrosis Factor-alpha / genetics
  • Tumor Necrosis Factor-alpha / metabolism
  • Tumor Necrosis Factor-alpha / pharmacology
  • Vascular Endothelial Growth Factor A / genetics
  • Vascular Endothelial Growth Factor A / metabolism
  • Vascular Endothelial Growth Factor A / pharmacology

Substances

  • Amyloid beta-Peptides
  • Cytokines
  • Inflammation Mediators
  • Interleukin-5
  • Tumor Necrosis Factor-alpha
  • Vascular Endothelial Growth Factor A