αν and β1 Integrins mediate Aβ-induced neurotoxicity in hippocampal neurons via the FAK signaling pathway

PLoS One. 2013 Jun 3;8(6):e64839. doi: 10.1371/journal.pone.0064839. Print 2014.

Abstract

αν and β1 integrins mediate Aβ-induced neurotoxicity in primary hippocampal neurons. We treated hippocampal neurons with 2.5 µg/mL 17E6 and 5 µg/mL ab58524, which are specific αν and β1 integrin antagonists, respectively, for 42 h prior to 10 µM Aβ treatment. Next, we employed small interfering RNA (siRNA) to silence focal adhesion kinase (FAK), a downstream target gene of integrins. The siRNAs were designed with a target sequence, an MOI of 10 and the addition of 5 µg/mL polybrene. Under these conditions, the neurons were transfected and the apoptosis of different cell types was detected. Moreover, we used real-time PCR and Western blotting analyses to detect the expression of FAK and ρFAK genes in different cell types and investigated the underlying mechanism and signal pathway by which αν and β1 integrins mediate Aβ-induced neurotoxicity in hippocampal neurons. An MTT assay showed that both 17E6 and ab58524 significantly increased cell viability compared with the Aβ-treated neurons (P<0.01 and P<0.05, respectively). However, this protective effect was markedly attenuated after transfection with silencing FAK (siFAK). Moreover, TUNEL immunostaining and flow cytometry indicated that both 17E6 and ab58524 significantly protected hippocampal neurons against apoptosis induced by Aβ (P<0.05) compared with the Aβ-treated cells. However, this protective effect was reversed with siFAK treatment. Both the gene and protein expression of FAK increased after Aβ treatment. Interestingly, as the gene and protein levels of FAK decreased, the ρFAK protein expression markedly increased. Furthermore, both the gene and protein expression of FAK and ρFAK were significantly diminished. Thus, we concluded that both αν and β1 integrins interfered with Aβ-induced neurotoxicity in hippocampal neurons and that this mechanism partially contributes to the activation of the Integrin-FAK signaling pathway.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amyloid beta-Peptides / toxicity*
  • Animals
  • Apoptosis / drug effects
  • Apoptosis / genetics
  • Cell Survival / drug effects
  • Cell Survival / genetics
  • Flow Cytometry
  • Focal Adhesion Protein-Tyrosine Kinases / genetics
  • Focal Adhesion Protein-Tyrosine Kinases / metabolism*
  • Gene Expression Regulation / drug effects
  • Hippocampus / pathology*
  • In Situ Nick-End Labeling
  • Integrin alphaV / metabolism*
  • Integrin beta1 / metabolism*
  • Lentivirus / metabolism
  • Microtubule-Associated Proteins / metabolism
  • Neurons / drug effects
  • Neurons / enzymology
  • Neurons / metabolism*
  • Neurons / pathology
  • Neuroprotective Agents / pharmacology
  • Neurotoxins / toxicity*
  • Phosphorylation / drug effects
  • RNA, Small Interfering / metabolism
  • Rats
  • Signal Transduction / drug effects
  • Signal Transduction / genetics
  • Transfection

Substances

  • Amyloid beta-Peptides
  • Integrin alphaV
  • Integrin beta1
  • Microtubule-Associated Proteins
  • Neuroprotective Agents
  • Neurotoxins
  • RNA, Small Interfering
  • Focal Adhesion Protein-Tyrosine Kinases

Grants and funding

The work was supported by National Natural Science Fundation (No. 30700244). The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.