title: Purinergic receptor signaling regulates N-cadherin expression in primary astrocyte cultures.
abstract: Extracellular ATP exerts both short-term and long-term effects in the CNS by stimulating cell-surface purinergic receptors. Here we have examined the effect of purinergic receptor activation on N-cadherin expression, a calcium-dependent cell adhesion molecule involved in many processes, including glia-glia and axon-glia interactions. When primary cultures of rat cortical astrocytes were treated with ATP, N-cadherin protein expression increased in a time- and concentration-dependent manner. In addition, ATP treatment caused an increase in N-cadherin immunoreactivity in both the cytoplasm and on the cell surface membrane. Interestingly, experiments with cycloheximide revealed that relocalization of N-cadherin to the cell surface membrane were independent of protein synthesis. The ATP-induced increase in N-cadherin protein expression was blocked by reactive blue 2 and 8-(p-sulfophenyl)-theophylline, suggesting involvement of both P2 and P1 purinergic receptors, respectively. In addition, N-cadherin expression was partially blocked when signaling from purinergic receptors to extracellular signal regulated protein kinase or Akt was inhibited by 1,4-diamino-2,3-dicyano-1,4-bis(2-aminophenylthio)butadiene or wortmannin, respectively. By using an in vitro model of traumatic CNS injury, we found that N-cadherin expression was increased when astrocytes were subjected to rapid and reversible mechanical strain. The findings presented here demonstrate a role for extracellular ATP, purinergic receptors and protein kinase signaling in regulating N-cadherin expression and suggest a role for this mechanism in cell-cell interactions.
authors.affiliation: Research Service, Miami VA Medical Center, Department of Pathology, the Neuroscience Program, University of Miami Miller School of Medicine, Miami, Florida, USA.
authors.forename: Minh D
authors.initials: MD
authors.lastname: Tran
authors.forename: Ina B
authors.initials: IB
authors.lastname: Wanner
authors.forename: Joseph T
authors.initials: JT
authors.lastname: Neary
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D015820:Cadherins / Q000235:genetics / Q000378:metabolism*; D002540:Cerebral Cortex / Q000166:cytology; D003513:Cycloheximide / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology*; D008954:Models, Biological; D011494:Protein Kinases / Q000378:metabolism; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D021381:Protein Transport / Q000187:drug effects; D051381:Rats; D018048:Receptors, Purinergic P2 / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D013997:Time Factors; D014947:Wounds and Injuries / Q000209:etiology / Q000378:metabolism
chemical_list: D015820:Cadherins; D004791:Enzyme Inhibitors; D011500:Protein Synthesis Inhibitors; D018048:Receptors, Purinergic P2; D000255:Adenosine Triphosphate; D003513:Cycloheximide; D011494:Protein Kinases