title: Role of adenosine receptors in regulating chemotaxis and cytokine production of plasmacytoid dendritic cells.
abstract: Plasmacytoid dendritic cells (PDCs) are potent regulators of immune function and the major source of type I interferon (IFN) following viral infection. PDCs are found at sites of inflammation in allergic reactions, autoimmune disorders, and cancer, but the mechanisms leading to the recruitment of PDCs to these sites remain elusive. During inflammation, adenosine is released and functions as a signaling molecule via adenosine receptors. This study analyzes adenosine receptor expression and function in human PDCs. Adenosine was found to be a potent chemotactic stimulus for immature PDCs via an A(1) receptor-mediated mechanism. The migratory response toward adenosine was comparable to that seen with CXCL12 (stromal-derived factor-1 alpha [SDF-1 alpha), the most potent chemotactic stimulus identified thus far for immature PDCs. Upon maturation, PDCs down-regulate the A(1) receptor, resulting in a loss of migratory function. In contrast, mature PDCs up-regulate the A(2a) receptor, which is positively coupled to adenylyl cyclase and has been implicated in the down-regulation of DC cytokine-producing capacity. We show that in mature PDCs adenosine reduces interleukin-6 (IL-6), IL-12, and IFN-alpha production in response to CpG oligodeoxynucleotides (ODN). These findings indicate that adenosine may play a dual role in PDC-mediated immunity by initially recruiting immature PDCs to sites of inflammation and by subsequently limiting the extent of the inflammatory response induced by mature PDCs by inhibiting their cytokine-producing capacity.
authors.affiliation: Ludwig Institute Oncology Unit, Melbourne Tumour Biology Branch, Austin and Repatriation Medical Centre, Studley Rd, Heidelberg, Victoria 3084, Australia.
authors.forename: Max
authors.initials: M
authors.lastname: Schnurr
authors.forename: Tracey
authors.initials: T
authors.lastname: Toy
authors.forename: Amanda
authors.initials: A
authors.lastname: Shin
authors.forename: Gunther
authors.initials: G
authors.lastname: Hartmann
authors.forename: Simon
authors.initials: S
authors.lastname: Rothenfusser
authors.forename: Julia
authors.initials: J
authors.lastname: Soellner
authors.forename: Ian D
authors.initials: ID
authors.lastname: Davis
authors.forename: Jonathan
authors.initials: J
authors.lastname: Cebon
authors.forename: Eugene
authors.initials: E
authors.lastname: Maraskovsky
mesh_terms: D000241:Adenosine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002633:Chemotaxis / Q000276:immunology*; D000242:Cyclic AMP / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism; D003713:Dendritic Cells / Q000276:immunology* / Q000378:metabolism*; D006801:Humans; D012333:RNA, Messenger / Q000032:analysis; D043682:Receptor, Adenosine A1 / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D043705:Receptor, Adenosine A2A / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D043704:Receptor, Adenosine A2B / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D043684:Receptor, Adenosine A3 / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D018047:Receptors, Purinergic P1 / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000276:immunology
chemical_list: D016207:Cytokines; D012333:RNA, Messenger; D043682:Receptor, Adenosine A1; D043705:Receptor, Adenosine A2A; D043704:Receptor, Adenosine A2B; D043684:Receptor, Adenosine A3; D018047:Receptors, Purinergic P1; D000242:Cyclic AMP; D000241:Adenosine; D002118:Calcium