Mechanisms of P2X7 receptor-mediated ERK1/2 phosphorylation in human astrocytoma cells.
Astrocytes are involved in normal and pathological brain functions, where they become activated and undergo reactive gliosis. Astrocytes have been shown to respond to extracellular nucleotides via the activation of P2 receptors, either G protein-coupled P2Y receptors or P2X receptors that are ligand-gated ion channels. In this study, we have examined the manner in which activation of the P2X(7) nucleotide receptor, an extracellular ATP-gated ion channel expressed in astrocytes, can lead to the phosphorylation of ERK1/2. Results showed that the P2X(7) receptor agonist 2',3'-O-(4-benzoyl)benzoyl-ATP induced ERK1/2 phosphorylation in human astrocytoma cells overexpressing the recombinant rat P2X(7) receptor (rP2X(7)-R), a response that was inhibited by the P2X(7) receptor antagonist, oxidized ATP. Other results suggest that rP2X(7)-R-mediated ERK1/2 phosphorylation was linked to the phosphorylation of the proline-rich/Ca(2+)-activated tyrosine kinase Pyk2, c-Src, phosphatidylinositol 3'-kinase, and protein kinase Cdelta activities and was dependent on the presence of extracellular Ca(2+). These results support the hypothesis that the P2X(7) receptor and its signaling pathways play a role in astrocyte-mediated inflammation and neurodegenerative disease.
Gendron
Fernand-Pierre
FP
Department of Biochemistry, University of Missouri-Columbia, Columbia, Missouri 65212, USA. fpgendron@hotmail.com
Neary
Joseph T
JT
Theiss
Patty M
PM
Sun
Grace Y
GY
Gonzalez
Fernando A
FA
Weisman
Gary A
GA
D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D001254:Astrocytoma; D001921:Brain / Q000378:metabolism*; D001932:Brain Neoplasms / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005911:Gliosis / Q000378:metabolism*; D006801:Humans; D019950:Mitogen-Activated Protein Kinase 1 / Q000187:drug effects / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000187:drug effects / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D020033:Protein Isoforms / Q000037:antagonists & inhibitors / Q000378:metabolism; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D018048:Receptors, Purinergic P2 / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D058486:Receptors, Purinergic P2X7; D014407:Tumor Cells, Cultured
C546468:P2RX7 protein, human; C546470:P2rx7 protein, rat; D020033:Protein Isoforms; D018048:Receptors, Purinergic P2; D058486:Receptors, Purinergic P2X7; D011493:Protein Kinase C; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D002118:Calcium