Alzheimer-associated neuronal thread protein mediated cell death is linked to impaired insulin signaling

J Alzheimers Dis. 2004 Jun;6(3):231-42. doi: 10.3233/jad-2004-6304.

Abstract

Alzheimer-associated neuronal thread protein, AD7c-NTP, accumulates in cortical neurons and co-localizes with phospho-tau-containing cytoskeletal lesions in brains with AD. Over-expression of AD7c-NTP results in increased neuronal death mediated by apoptosis and mitochondrial dysfunction. Empirical studies demonstrating differential growth factor responses to AD7c-NTP led to us to further investigate the effects of insulin, insulin-like growth factor, type 1 (IGF-1), nerve growth factor (NGF), and platelet-derived growth factor (PDGF) stimulation on neuronal survival mechanisms in relation to AD7c-NTP expression. PNET2 human CNS-derived neuronal cells were stably transfected with a cDNA encoding AD7c-NTP or chloramphenicol acetyl transferase (CAT) whereby gene expression was regulated by an inducible promoter. In cells that expressed AD7c-NTP, insulin or IGF-1 stimulation was associated with reduced viability with increased levels of p53, p21/Waf-1, phospho-JNK, and phospho-tau, and reduced levels of Bcl-2 and phospho-Erk MAPK. In contrast, AD7c-NTP-transfected cells stimulated with NGF or PDGF, and CAT-transfected cells stimulated with any one of the four growth factors remained viable and had low levels of p53, p21/Waf-1, phospho-JNK, and phospho-tau, and abundant Bcl-2 and phospho-Erk expression. The results suggest that reduced survival in neurons that over-express AD7c-NTP may be mediated by impaired insulin/IGF-1 signaling, and that CNS neurons with abundant insulin or IGF-1 receptors may be particularly vulnerable to the adverse effects of AD7c-NTP.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Alzheimer Disease / genetics
  • Alzheimer Disease / metabolism*
  • Alzheimer Disease / physiopathology*
  • Animals
  • Antibodies, Monoclonal / metabolism
  • Blotting, Western
  • Brain / metabolism*
  • Brain / physiopathology*
  • Calcium-Binding Proteins / genetics
  • Calcium-Binding Proteins / metabolism
  • Cell Death / physiology
  • DNA, Complementary / genetics
  • Genes, bcl-2 / genetics
  • Humans
  • Insulin / genetics
  • Insulin / metabolism*
  • Insulin-Like Growth Factor I / genetics
  • Insulin-Like Growth Factor I / metabolism
  • Lithostathine
  • Nerve Growth Factor / genetics
  • Nerve Growth Factor / metabolism
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / metabolism
  • Platelet-Derived Growth Factor / genetics
  • Platelet-Derived Growth Factor / metabolism
  • Promoter Regions, Genetic / genetics
  • Signal Transduction / physiology*

Substances

  • AD7c-NTP protein, human
  • Antibodies, Monoclonal
  • Calcium-Binding Proteins
  • DNA, Complementary
  • Insulin
  • Lithostathine
  • Nerve Tissue Proteins
  • Platelet-Derived Growth Factor
  • Insulin-Like Growth Factor I
  • Nerve Growth Factor