title: P2Y receptors activate neuroprotective mechanisms in astrocytic cells.
abstract: Mechanical or ischemic trauma to the CNS causes the release of nucleotides and other neurotransmitters into the extracellular space. Nucleotides can activate nucleotide receptors that modulate the expression of genes implicated in cellular adaptive responses. In this investigation, we used human 1321N1 astrocytoma cells expressing a recombinant P2Y2 receptor to assess the role of this receptor in the regulation of anti-apoptotic (bcl-2 and bcl-xl) and pro-apoptotic (bax) gene expression. Acute treatment with the P2Y2 receptor agonist UTP up-regulated bcl-2 and bcl-xl, and down-regulated bax, gene expression. Activation of P2Y2 receptors was also coupled to the phosphorylation of cyclic AMP responsive element binding protein that positively regulates bcl-2 and bcl-xl gene expression. Cyclic AMP responsive element decoy oligonucleotides markedly attenuated the UTP-induced increase in bcl-2 and bcl-xl mRNA levels. Activation of P2Y2 receptors induced the phosphorylation of the pro-apoptotic factor Bad and caused a reduction in bax/bcl-2 mRNA expression ratio. All these signaling pathways are known to be involved in cell survival mechanisms. Using cDNA microarray analysis and RT-PCR, P2Y2 receptors were found to up-regulate the expression of genes for neurotrophins, neuropeptides and growth factors including nerve growth factor 2; neurotrophin 3; glia-derived neurite-promoting factor, as well as extracellular matrix proteins CD44 and fibronectin precursor--genes known to regulate neuroprotection. Consistent with this observation, conditioned media from UTP-treated 1321N1 cells expressing P2Y2 receptors stimulated the outgrowth of neurites in PC-12 cells. Taken together, our results suggest an important novel role for the P2Y2 receptor in survival and neuroprotective mechanisms under pathological conditions.
authors.affiliation: Department of Chemistry, Rio Piedras Campus, University of Puerto Rico, San Juan, Puerto Rico.
authors.forename: Nataliya E
authors.initials: NE
authors.lastname: Chorna
authors.forename: Laura I
authors.initials: LI
authors.lastname: Santiago-Pérez
authors.forename: Laurie
authors.initials: L
authors.lastname: Erb
authors.forename: Cheikh I
authors.initials: CI
authors.lastname: Seye
authors.forename: Joseph T
authors.initials: JT
authors.lastname: Neary
authors.forename: Grace Y
authors.initials: GY
authors.lastname: Sun
authors.forename: Gary A
authors.initials: GA
authors.lastname: Weisman
authors.forename: Fernando A
authors.initials: FA
authors.lastname: González
mesh_terms: D000818:Animals; D001081:Apyrase / Q000494:pharmacology; D001253:Astrocytes / Q000187:drug effects / Q000502:physiology*; D001254:Astrocytoma; D015153:Blotting, Western / Q000379:methods; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D017077:Culture Media, Conditioned / Q000494:pharmacology; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects / Q000502:physiology*; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D018960:Hyaluronan Receptors / Q000235:genetics / Q000378:metabolism; D018613:Microscopy, Confocal / Q000379:methods; D009414:Nerve Growth Factors / Q000235:genetics / Q000378:metabolism; D016501:Neurites / Q000187:drug effects / Q000378:metabolism; D009479:Neuropeptides / Q000235:genetics / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods; D009841:Oligonucleotides / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D018048:Receptors, Purinergic P2 / Q000235:genetics / Q000502:physiology*; D058473:Receptors, Purinergic P2Y2; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D013997:Time Factors; D014162:Transfection / Q000379:methods; D014544:Uridine Triphosphate / Q000494:pharmacology; D051020:bcl-X Protein
chemical_list: C494811:BCL2L1 protein, human; C494813:Bcl2l1 protein, rat; D017077:Culture Media, Conditioned; D017362:Cyclic AMP Response Element-Binding Protein; D004791:Enzyme Inhibitors; D018960:Hyaluronan Receptors; D009414:Nerve Growth Factors; D009479:Neuropeptides; D009841:Oligonucleotides; C546385:P2RY2 protein, human; C546387:P2ry2 protein, rat; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D018048:Receptors, Purinergic P2; D058473:Receptors, Purinergic P2Y2; D051020:bcl-X Protein; D001081:Apyrase; D014544:Uridine Triphosphate