P2X7 receptors on microglial cells mediate injury to cortical neurons in vitro

• Published in: Glia 2006-08, Vol.54 (3), p.234-242
• Main Authors: Skaper, Stephen D., Facci, Laura, Culbert, Ainsley A., Evans, Nicholas A., Chessell, Iain, Davis, John B., Richardson, Jill C.
• Format: Article
• Language: English
• Subjects: Alzheimer's disease; ATP; Biological and medical sciences; central nervous system; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Fundamental and applied biological sciences. Psychology; gene deletion; glia; inflammation; Isolated neuron and nerve. Neuroglia; Medical sciences; neurodegeneration; Neurology; purinergic receptor; reactive oxide species; Vertebrates: nervous system and sense organs
• ISSN: 0894-1491; 1098-1136
• DOI: 10.1002/glia.20379

The P2X7 receptor has been implicated in the release of cytokines and in the induction of cell death, and is up‐regulated in a transgenic mouse model of Alzheimer's disease. Using cocultures of rat cortical neurons and microglia, we show that ATP and the more potent P2X7 agonist benzoylbenzoyl‐ATP (BzATP) cause neuronal cell injury. The deleterious effects of BzATP‐treated microglia were prevented by nonselective P2X antagonists (PPADS and oxidized ATP) and by the more selective P2X7 antagonist Brilliant Blue G. Similar concentrations of BzATP caused release of superoxide and nitric oxide from isolated microglia, and neuronal cell injury was attenuated by a superoxide dismutase mimetic and by a peroxynitrite decomposition catalyst, suggesting a role for reactive oxide species. Cocultures composed of wild‐type cortical neurons, and microglia from P2X7 receptor‐deficient mice failed to exhibit neuronal cell injury in the presence of BzATP, but retained sensitivity to injury when microglia were derived from genotypically matched normal (P2X7+/+ mice), thereby establishing P2X7 involvement in the injury process. P2X7 receptor activation on microglia thus appears necessary for microglial‐mediated injury of neurons, and proposes that targeting P2X7 receptors may constitute a novel approach for the treatment of acute and chronic neurodegenerative disorders where a microglial component is evident. © 2006 Wiley‐Liss, Inc.