Neuroprotective effect of protease-activated receptor-2 in the hypoxia-induced apoptosis of rat RGC-5 cells

J Mol Neurosci. 2013 May;50(1):98-108. doi: 10.1007/s12031-012-9876-4. Epub 2012 Sep 5.

Abstract

Hypoxia-induced apoptosis of retinal ganglion cells (RGCs) is regarded as a pivotal pathological process in various ocular diseases. Protease-activated receptor-2 (PAR-2) is involved in the regulation of cell inflammation, differentiation, and apoptosis in many cell types and tissues, but the role of PAR-2 in RGCs under pathological conditions remains unknown. The purpose of this study was to investigate the role of PAR-2 in the apoptosis of RGCs under hypoxic stress. An immortalized rat RGC line (RGC-5) was exposed to hypoxia (5 % O₂). The expression and location of PAR-2 in RGC-5 cells under hypoxia stress were investigated using real-time PCR, western blotting and immunocytochemistry. Cell viability was determined using the Cell Counting Kit-8 assay. Apoptosis was detected using Hoechst 33342 staining and AnnexinV-FITC/PI assays. The role of Bcl-2, Bax, and the active subunit of caspase-3 was also investigated. The results showed that PAR-2 was functionally expressed in RGC-5 cells and up-regulated at both mRNA and protein levels under hypoxic stress. The PAR-2 selective agonist, SLIGRL, rescued RGC-5 cells from hypoxia-induced apoptosis through up-regulation of the Bcl-2/Bax ratio and down-regulation of caspase-3 activation. This study provides the first evidence that PAR-2 has a protective effect against the hypoxia-induced apoptosis of RGC-5 cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis* / genetics
  • Cell Hypoxia
  • Cell Line
  • Cell Survival
  • Protein Transport
  • Rats
  • Receptor, PAR-2 / genetics
  • Receptor, PAR-2 / metabolism*
  • Retinal Ganglion Cells / metabolism*
  • Transcription, Genetic
  • Up-Regulation

Substances

  • Receptor, PAR-2