Involvement of N-cadherin in the protective effect of glial cell line-derived neurotrophic factor on dopaminergic neuron damage

Int J Mol Med. 2013 Mar;31(3):561-8. doi: 10.3892/ijmm.2013.1226. Epub 2013 Jan 3.

Abstract

The aim of this study was to further confirm that glial cell line-derived neurotrophic factor (GDNF) exerts a neuro-protective effect on dopaminergic neurons (DAs) and to investigate the protective mechanism. Cadherins are calcium-dependent adhesion proteins, and N-cadherins are found in neurons. Our study attempted to ascertain whether GDNF activates the PI3K/Akt signaling pathway through the mediation of N-cadherin to confer a protective effect on DAs. Flow cytometry and Hoechst 33258 staining results indicated that the apoptosis rate of damaged neurocytes increased following interference of N-cadherin expression. Immunoblotting results demonstrated that the amount of phosphorylated Akt (p-Akt) in the cytoplasm decreased, while the total Akt quantity remained unchanged following interference of N-cadherin expression. The immunohistochemical staining results demonstrated that the levels of total N-cadherin, phosphorylated N-cadherin (Tyr860) and p-Akt decreased; however, the amount of total Akt remained unchanged. In addition, we also demonstrated that Tyr860 and p-Akt levels were reduced in a GDNF dose-dependent manner with the phosphorylation level peaking at GDNF dose of 50 ng/ml (in vitro) and 50 ng/4 µl (in vivo), and also in a time-dependent manner with the phosphorylation level peaking at 15 min (in vitro) and 30 min (in vivo). Statistical analysis also showed that changes in the phosphorylation levels of Tyr860 and p-Akt demonstrated a positive correlation. Collectively, GDNF activates the PI3K/Akt pathway via N-cadherin to protect DAs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis
  • Cadherins / genetics
  • Cadherins / metabolism*
  • Cell Line
  • Dopaminergic Neurons / metabolism*
  • Glial Cell Line-Derived Neurotrophic Factor / metabolism
  • Glial Cell Line-Derived Neurotrophic Factor / pharmacology*
  • Male
  • Mice
  • Nerve Growth Factors / metabolism*
  • Neuroglia / metabolism
  • Neuroprotective Agents
  • Parkinson Disease / metabolism
  • Phosphatidylinositol 3-Kinases / metabolism*
  • Phosphorylation
  • Proto-Oncogene Proteins c-akt / metabolism*
  • RNA Interference
  • RNA, Small Interfering
  • Rats
  • Rats, Sprague-Dawley
  • Signal Transduction

Substances

  • Cadherins
  • Glial Cell Line-Derived Neurotrophic Factor
  • Nerve Growth Factors
  • Neuroprotective Agents
  • RNA, Small Interfering
  • Phosphatidylinositol 3-Kinases
  • Proto-Oncogene Proteins c-akt