title: P2Y1 Receptor Activation of the TRPV4 Ion Channel Enhances Purinergic Signaling in Satellite Glial Cells.
abstract: Transient receptor potential (TRP) ion channels of peripheral sensory pathways are important mediators of pain, itch, and neurogenic inflammation. They are expressed by primary sensory neurons and by glial cells in the central nervous system, but their expression and function in satellite glial cells (SGCs) of sensory ganglia have not been explored. SGCs tightly ensheath neurons of sensory ganglia and can regulate neuronal excitability in pain and inflammatory states. Using a modified dissociation protocol, we isolated neurons with attached SGCs from dorsal root ganglia of mice. SGCs, which were identified by expression of immunoreactive Kir4.1 and glutamine synthetase, were closely associated with neurons, identified using the pan-neuronal marker NeuN. A subpopulation of SGCs expressed immunoreactive TRP vanilloid 4 (TRPV4) and responded to the TRPV4-selective agonist GSK1016790A by an influx of Ca(2+) ions. SGCs did not express functional TRPV1, TRPV3, or TRP ankyrin 1 channels. Responses to GSK1016790A were abolished by the TRPV4 antagonist HC067047 and were absent in SGCs from Trpv4(-/-) mice. The P2Y1-selective agonist 2-methylthio-ADP increased [Ca(2+)]i in SGCs, and responses were prevented by the P2Y1-selective antagonist MRS2500. P2Y1 receptor-mediated responses were enhanced in TRPV4-expressing SGCs and HEK293 cells, suggesting that P2Y1 couples to and activates TRPV4. PKC inhibitors prevented P2Y1 receptor activation of TRPV4. Our results provide the first evidence for expression of TRPV4 in SGCs and demonstrate that TRPV4 is a purinergic receptor-operated channel in SGCs of sensory ganglia.
authors.affiliation: From the Monash Institute of Pharmaceutical Sciences, Australian Research Council Centre of Excellence in Convergent Bio-Nano Science and Technology, and.
authors.forename: Pradeep
authors.initials: P
authors.lastname: Rajasekhar
authors.affiliation: From the Monash Institute of Pharmaceutical Sciences, Australian Research Council Centre of Excellence in Convergent Bio-Nano Science and Technology, and the Departments of Anatomy and Neuroscience.
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Poole
authors.affiliation: the Department of Neurology, School of Medicine, Duke University, Durham, North Carolina 27710.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Liedtke
authors.affiliation: From the Monash Institute of Pharmaceutical Sciences, Australian Research Council Centre of Excellence in Convergent Bio-Nano Science and Technology, and Department of Anaesthesia and Peri-operative Medicine, Monash University, Victoria 3052, Australia, Pharmacology and Therapeutics, University of Melbourne, Parkville, Victoria 3010, Australia, and nigel.bunnett@monash.edu.
authors.forename: Nigel W
authors.initials: NW
authors.lastname: Bunnett
authors.affiliation: From the Monash Institute of Pharmaceutical Sciences, Australian Research Council Centre of Excellence in Convergent Bio-Nano Science and Technology, and Genetics, and nicholas.veldhuis@monash.edu.
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Veldhuis
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology*; D057809:HEK293 Cells; D006801:Humans; D007930:Leucine / Q000031:analogs & derivatives / Q000494:pharmacology; D051379:Mice; D018345:Mice, Knockout; D009457:Neuroglia / Q000166:cytology / Q000378:metabolism*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D058472:Receptors, Purinergic P2Y1 / Q000235:genetics / Q000378:metabolism*; D013449:Sulfonamides / Q000494:pharmacology; D050916:TRPV Cation Channels / Q000235:genetics / Q000378:metabolism*
chemical_list: C530602:N-(1-((4-(2-(((2,4-dichlorophenyl)sulfonyl)amino)-3-hydroxypropanoyl)-1-piperazinyl)carbonyl)-3-methylbutyl)-1-benzothiophene-2-carboxamide; D047428:Protein Kinase Inhibitors; D058472:Receptors, Purinergic P2Y1; D013449:Sulfonamides; D050916:TRPV Cation Channels; C416986:TRPV4 protein, human; C486576:Trpv4 protein, mouse; D000244:Adenosine Diphosphate; D011493:Protein Kinase C; D007930:Leucine; D002118:Calcium
keywords: G protein-coupled receptor (GPCR); Satellite glial cells; cell signaling; inflammation; nociception; purinergic receptor; transient receptor potential channels (TRP channels)