Elevated neuronal α-synuclein promotes microglia activation after spinal cord ischemic/reperfused injury

Neuroreport. 2015 Aug 5;26(11):656-61. doi: 10.1097/WNR.0000000000000406.

Abstract

The present study aimed to investigate the mechanism of injured neurons caused by ischemia/reperfusion in the induction of microglia activation. Spinal neurons were prepared and exposed to ischemic/reperfused conditions. The α-synuclein protein levels in these cells were analyzed by western blot, immunofluorescence, or enzyme-linked immunosorbent assay. Ischemia/reperfusion exposure led to elevated α-synuclein protein expression and release. Furthermore, when cocultured with injured neurons or supernatants from injured neurons, nitric oxide generation, H2O2 production, and tumor necrosis factor-α expression were promoted in microglia. Nevertheless, this effect was impeded by pretreatment of the α-synuclein antibody in the supernatants from injured neurons. Moreover, toll-like receptor 2 (TLR2) rather than TLR3 or TLR4 mediated microglia activation by α-synuclein. This process involved p38 MAPK and NF-κB activation, the inhibition of which resulted in reduced NADPH oxidase 2 (Nox2) in microglia. In conclusion, ischemia/reperfusion-injured neurons could express and release increased levels of α-synuclein and cause microglia activation through TLR2 both in vitro and in vivo.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Newborn
  • Antibodies / pharmacology
  • Cells, Cultured
  • Coculture Techniques
  • Embryo, Mammalian
  • Enzyme-Linked Immunosorbent Assay
  • Gene Expression Regulation
  • Hydrogen Peroxide / metabolism
  • Ischemia / metabolism
  • Ischemia / pathology*
  • Microglia / drug effects
  • Microglia / metabolism*
  • Neurons / enzymology*
  • Nitric Oxide / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Reperfusion Injury / metabolism
  • Reperfusion Injury / pathology*
  • Spinal Cord / cytology*
  • Time Factors
  • Toll-Like Receptor 2 / genetics
  • Toll-Like Receptor 2 / metabolism
  • Tumor Necrosis Factor-alpha / metabolism
  • alpha-Synuclein / immunology
  • alpha-Synuclein / metabolism*

Substances

  • Antibodies
  • Tlr2 protein, rat
  • Toll-Like Receptor 2
  • Tumor Necrosis Factor-alpha
  • alpha-Synuclein
  • Nitric Oxide
  • Hydrogen Peroxide