Phosphorylation of eukaryotic initiation factor-2alpha (eIF2alpha) is associated with neuronal degeneration in Alzheimer's disease

Neuroreport. 2002 Dec 20;13(18):2429-32. doi: 10.1097/00001756-200212200-00011.

Abstract

Inhibition of protein translation is a mode of inducing neuronal apoptosis and neurodegeneration in Alzheimer's disease (AD). Phosphorylation of eukaryotic initiation factor-2alpha (eIF2alpha) terminates global protein translation and induces apoptosis. We examined whether this signaling pathway occurs in degenerating neurons of AD. Brain sections from young individuals, age-matched control individuals and AD patients were examined for immunoreactivity of phosphorylated eIF2alpha by immunohistochemical analysis. While young brain sections did not display and age-matched brain sections have mild immunoreactive positive cells, AD brain sections revealed intense immunoreactivity for phosphorylated eIF2alpha. Most of the phosphorylated eIF2alpha immunoreactive positive neurons have high immunoreactivity for phosphorylated tau using AT8 antibody. Also, intense staining of phosphorylated eIF2alpha is associated vacuoles in degenerating neurons. This phenomenon was also observed for the immunohistochemical staining of phosphorylated PKR (double-stranded RNA-dependent protein kinase), the upstream kinase for eIF2alpha. Activation of PKR-eIF2alpha pathway is considered to be pro-apoptotic. In addition, formation of autophagy is regulated by eIF2alpha kinase. Therefore, it is concluded that phosphorylation of eIF2alpha is associated with the degeneration of neurons in AD.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Alzheimer Disease / metabolism*
  • Alzheimer Disease / pathology
  • Eukaryotic Initiation Factor-2 / metabolism*
  • Female
  • Fluorescent Antibody Technique
  • Fluorescent Dyes
  • Humans
  • Male
  • Nerve Degeneration / metabolism*
  • Nerve Degeneration / pathology
  • Phosphorylation
  • Signal Transduction

Substances

  • Eukaryotic Initiation Factor-2
  • Fluorescent Dyes