title: P2X7 receptor activation mediates retinal ganglion cell death in a human retina model of ischemic neurodegeneration.
abstract: OBJECTIVE
  There is evidence implicating ischemia and excitotoxicity in the pathogenesis of glaucoma. ATP-mediated excitotoxicity via activation of the P2X7 receptor (P2X7R) has been proposed to play a role in retinal ganglion cell (RGC) degeneration in this disease. The aim of this research was to determine whether stimulation of the P2X7R mediated ischemia-induced RGC death in the human retina.
  
  
  METHODS
  Human organotypic retinal cultures were exposed to the P2X7R agonist 2',3'-O-(4-benzoylbenzoyl)-ATP (BzATP) and simulated ischemia (oxygen/glucose deprivation) in the presence or absence of the P2X7R antagonist, Brilliant Blue G (BBG). Neuronal death in the RGC layer was quantified by neuronal nuclei (NeuN)-positive cell counts and quantitative real-time PCR for THY-1 mRNA. The P2X7R was localized by immunohistochemistry and P2X7R mRNA profiling using a cryosectioning technique.
  
  
  RESULTS
  P2X7R stimulation by BzATP (100 μM) induced loss of RGC markers in human organotypic retinal cultures (HORCs), which was inhibited by BBG (1 μM). Simulated ischemia led to loss of RGCs that was also inhibited by BBG, indicating that ischemia-induced RGC degeneration was mediated by the P2X7R. The P2X7R was immunolocalized to the outer and inner plexiform layers of the human retina, and P2X7R mRNA expression was confirmed in the inner retina and ganglion cell layer.
  
  
  CONCLUSIONS
  These studies demonstrated that stimulation of the P2X7R can mediate RGC death and that this mechanism plays a role in ischemia-induced neurodegeneration in the human retina.
authors: School of Pharmacy, University of East Anglia, Norwich, United Kingdom.
authors: Nuwan
authors: N
authors: Niyadurupola
authors: Peter
authors: P
authors: Sidaway
authors: Ning
authors: N
authors: Ma
authors: Jeremy D
authors: JD
authors: Rhodes
authors: David C
authors: DC
authors: Broadway
authors: Julie
authors: J
authors: Sanderson
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000494:pharmacology; D016923:Cell Death; D002478:Cells, Cultured; D006801:Humans; D007150:Immunohistochemistry; D007511:Ischemia / Q000150:complications*; D008954:Models, Biological; D058911:Purinergic P2X Receptor Agonists / Q000494:pharmacology*; D058486:Receptors, Purinergic P2X7 / Q000378:metabolism; D012162:Retinal Degeneration / Q000209:etiology / Q000378:metabolism / Q000473:pathology*; D012165:Retinal Ganglion Cells / Q000187:drug effects* / Q000502:physiology
chemical_list: D058911:Purinergic P2X Receptor Agonists; D058486:Receptors, Purinergic P2X7; C033901:3'-O-(4-benzoyl)benzoyladenosine 5'-triphosphate; D000255:Adenosine Triphosphate