Activation of P2X₇ receptors induces CCL3 production in microglial cells through transcription factor NFAT

• Published in: Journal of neurochemistry 2009-01, Vol.108 (1), p.115-125
• Main Authors: Kataoka, Ayako, Tozaki-Saitoh, Hidetoshi, Koga, Yui, Tsuda, Makoto, Inoue, Kazuhide
• Format: Article
• Language: English
• Subjects: Adenosine triphosphatase; Adenosine Triphosphate - pharmacology; Animals; Animals, Newborn; Anti-Bacterial Agents - pharmacology; ATP; Biochemistry; Biological and medical sciences; Brain - cytology; Calcimycin - pharmacology; Cells, Cultured; Cellular biology; Central nervous system; Central neurotransmission. Neuromudulation. Pathways and receptors; chemokine; Chemokine CCL3 - genetics; Chemokine CCL3 - metabolism; cytokine; Cytokines; Dose-Response Relationship, Drug; Enzyme Inhibitors - pharmacology; Enzyme-Linked Immunosorbent Assay - methods; Estrenes - pharmacology; Fundamental and applied biological sciences. Psychology; glia; inflammation; Isolated neuron and nerve. Neuroglia; Mice; Microglia - drug effects; Microglia - metabolism; Neurology; NFATC Transcription Factors - metabolism; Phosphodiesterase Inhibitors - pharmacology; Protein Transport - drug effects; purinergic; Pyrrolidinones - pharmacology; Rats; Receptors, Purinergic P2 - physiology; Receptors, Purinergic P2X7; Time Factors; Vertebrates: nervous system and sense organs
• ISSN: 0022-3042; 1471-4159
• DOI: 10.1111/j.1471-4159.2008.05744.x

Microglia are implicated as a source of diverse proinflammatory factors in the CNS. Extracellular nucleotides are well known to be potent activators of glial cells and trigger the release of cytokines from microglia through purinergic receptors. However, little is known about the role of purinoceptors in microglial chemokine release. In this study, we found that high concentrations of ATP evoked release of CC-chemokine ligand 3 (CCL3)/macrophage inflammatory protein-1α from MG-5 cells, a mouse microglial cell line, and rapid up-regulation of CCL3 mRNA was elicited within 30 min of ATP stimulation. The release of CCL3 was also stimulated by 2'- and 3'-O-(4-benzoylbenzoyl) ATP, an agonist of P2X₇ receptors. Brilliant Blue G, an antagonist of P2X₇ receptors, strongly inhibited this ATP-induced CCL3 release. Similar pharmacological profile was observed in primary microglia. In MG-5 cells, ATP caused de-phosphorylation and nuclear translocation of the transcription factor nuclear factor of activated T cells (NFAT). ATP-induced NFAT de-phosphorylation was also dependent on P2X₇ receptor activation. Furthermore, ATP-induced CCL3 release and production were prevented by a selective inhibitor of NFAT. Taken together, the results of this study demonstrate an involvement of NFAT in the mechanism underlying P2X₇ receptor-mediated CCL3 release.