Premium
P2Y receptors in brain astroglial cells: Identification of a gliotic P2Y receptor coupled to activation of a calcium‐independent ras/ERK 1/2 pathway
Author(s) -
Brambilla Roberta,
Neary Joseph T.,
Fumagalli Marta,
Cottini Lorenzo,
Cattabeni Flaminio,
Schiller Paul R.,
Abbracchio Maria P.
Publication year - 2003
Publication title -
drug development research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.582
H-Index - 60
eISSN - 1098-2299
pISSN - 0272-4391
DOI - 10.1002/ddr.10217
Subject(s) - ppads , phospholipase c , gliosis , p2y receptor , pertussis toxin , astrogliosis , p2 receptor , signal transduction , receptor , mapk/erk pathway , microbiology and biotechnology , calcium in biology , kinase , stimulation , extracellular , biology , chemistry , purinergic receptor , biochemistry , endocrinology , g protein , neuroscience , central nervous system
Exposure of rat cortical astrocytes to αβmethyleneATP results in features of reactive astrogliosis via activation of a novel P2Y receptor linked to cyclooxygenase‐2 (COX‐2) upregulation [Brambilla et al., J Neurochem 2002, 83:1285–1296]. Here, we have investigated the role of extracellular signal‐regulated kinases (ERK1/2) in αβmethyleneATP‐induced gliosis. Challenge of cultures with αβmethyleneATP resulted in early (5–10 min) and marked time‐dependent ERK1/2 activation. Pertussis toxin completely abolished this effect. ERK1/2 activation was also completely prevented by the selective ERK1/2 inhibitor PD 098059 and by the P2 antagonist pyridoxalphosphate‐6‐azophenyl‐2′‐4′‐disulphonic acid. Because αβmethyleneATP induced no changes of intracellular calcium concentrations “Brambilla et al., 2002”, a role for phosphoinositide‐specific phospholipase C was ruled out. Conversely, D609, an inhibitor of phosphatidylcholine‐PLC (PC‐PLC) and PLD, fully abolished both αβmethyleneATP‐induced ERK1/2 activation and the associated gliosis. The Ras inhibitor FTI‐277 could also partially abolish ERK1/2 activation. Exposure of cells to αβmethyleneATP resulted in a time‐dependent increase in the DNA binding activity of AP‐1 and NF‐κB, two transcription factors known to be phosphorylated by ERKs and involved in COX‐2 gene transcription. We conclude that stimulation of a gliotic P2Y receptor leads to ERK1/2 activation via multiple parallel signaling pathways involving G i/o ‐dependent and calcium‐independent stimulation of PC‐PLC and/or PLD, and consequent activation of the Ras/Raf systems. We are currently trying to clone this receptor from these cells. Its molecular identification may lead to the development of a new class of antineurodegenerative agents, which, by counteracting excessive gliosis and COX‐2 upregulation, may prove useful in neurological disorders characterized by astrogliosis and inflammation. Drug Dev. Res. 59:161–170, 2003. © 2003 Wiley‐Liss, Inc.