P2X7 nucleotide receptor activation enhances IFN gamma-induced type II nitric oxide synthase activity in BV-2 microglial cells.
Under normal and pathological conditions, brain cells release nucleotides that regulate a wide range of cellular responses due to activation of P2 nucleotide receptors. In this study, the effect of extracellular nucleotides on IFN gamma-induced NO release in murine BV-2 microglial cells was investigated. BV-2 cells expressed mRNA for metabotropic P2Y and ionotropic P2X receptors. Among the P2 receptor agonists tested, ATP, ADP, 2',3'-O-(4-benzoylbenzoyl)-ATP (BzATP), and 2-methylthio-ATP (2-MeSATP), but not UTP, enhanced IFN gamma-induced iNOS expression and NO production, suggesting that the uridine nucleotide receptors P2Y2 and P2Y6 are not involved in this response. U0126, an antagonist for MEK1/2, a kinase that phosphorylates the extracellular signal-regulated kinases ERK1/2, decreased IFN gamma-induced NO production. BzATP, a potent P2X7 receptor agonist, was more effective than ATP, ADP, or 2-MeSATP at enhancing IFN gamma-induced ERK1/2 phosphorylation. Consistent with activation of the P2X7 receptor, periodate-oxidized ATP, a P2X7 receptor antagonist, and suramin, a non-specific P2 receptor antagonist, inhibited the effect of ATP or BzATP on IFN gamma-induced NO production, whereas pyridoxal-phosphate-6-azophenyl-2',4'-disulfonic acid (PPADS), an antagonist of several P2X receptor subtypes, was ineffective. These results suggest that activation of P2X7 receptors may contribute to inflammatory responses in microglial cells seen in neurodegenerative diseases.
D000244:Adenosine Diphosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D002460:Cell Line; D004357:Drug Synergism; D004789:Enzyme Activation / Q000187:drug effects; D020536:Enzyme Activators / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007371:Interferon-gamma / Q000494:pharmacology*; D051379:Mice; D017628:Microglia / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000187:drug effects / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II; D018048:Receptors, Purinergic P2 / Q000187:drug effects / Q000378:metabolism*; D058486:Receptors, Purinergic P2X7; D013873:Thionucleotides / Q000494:pharmacology; D014544:Uridine Triphosphate / Q000494:pharmacology
D020536:Enzyme Activators; D004791:Enzyme Inhibitors; C546469:P2rx7 protein, mouse; D018048:Receptors, Purinergic P2; D058486:Receptors, Purinergic P2X7; D013873:Thionucleotides; D009569:Nitric Oxide; C033901:3'-O-(4-benzoyl)benzoyladenosine 5'-triphosphate; D000244:Adenosine Diphosphate; D007371:Interferon-gamma; D000255:Adenosine Triphosphate; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D014544:Uridine Triphosphate; C008501:2-methylthio-ATP