title: Extracellular adenosine 5'-triphosphate modulates interleukin-6 production by human thyrocytes through functional purinergic P2 receptors.
abstract: We investigated the presence of P2 receptors (P2Rs) in human thyrocytes and their possible involvement in the modulation of cytokine release. P2Rs expression was assessed by RT-PCR and, when possible, by immunoblotting. Human primary thyrocytes express the mRNA for the following P2X and P2Y subtypes: P2X(3), P2X(5), P2X(6), P2X(7), and P2Y(1), P2Y(2), P2Y(4), and P2Y(11). Stimulation with extracellular nucleotides of fura-2-loaded thyrocytes triggered an intracellular Ca(2+) signal, suggesting expression of functional receptors. Thyrocytes spontaneously released the proinflammatory cytokine IL-6. The ATP-hydrolyzing enzyme apyrase reduced basal IL-6 release, whereas extracellular ATP dose-dependently increased IL-6 secretion. Uridine 5'-triphosphate was also an effective stimulus, whereas benzoyl-ATP was ineffective, suggesting a P2Y- rather than P2X-modulated response. Finally, TSH reduced both the intracellular Ca(2+) ([Ca(2+)](i)) rise and IL-6 release triggered by P2Rs stimulation. In conclusion, we provide functional, pharmacological, and biochemical evidence that human primary thyrocytes express P2YR and P2XR subtypes, coupled to increases in ([Ca(2+)](i)) and secretion of IL-6. P2R-dependent modulation of IL-6 release from human thyrocytes suggests a novel mechanism whereby an inflammatory and/or immune-mediated damage can be initiated and amplified in the thyroid.
authors.affiliation: Department of Internal Medicine, University of Pisa, Via Roma 67, I-56100 Pisa. Italy.
authors.forename: Nadia
authors.initials: N
authors.lastname: Caraccio
authors.forename: Fabio
authors.initials: F
authors.lastname: Monzani
authors.forename: Eleonora
authors.initials: E
authors.lastname: Santini
authors.forename: Sabina
authors.initials: S
authors.lastname: Cuccato
authors.forename: Davide
authors.initials: D
authors.lastname: Ferrari
authors.forename: Maria Giulia
authors.initials: MG
authors.lastname: Callegari
authors.forename: Sara
authors.initials: S
authors.lastname: Gulinelli
authors.forename: Cinzia
authors.initials: C
authors.lastname: Pizzirani
authors.forename: Francesco
authors.initials: F
authors.lastname: Di Virgilio
authors.forename: Ele
authors.initials: E
authors.lastname: Ferrannini
authors.forename: Anna
authors.initials: A
authors.lastname: Solini
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology / Q000502:physiology*; D019898:Autocrine Communication; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D045604:Extracellular Fluid / Q000378:metabolism*; D006801:Humans; D015850:Interleukin-6 / Q000096:biosynthesis* / Q000378:metabolism; D007425:Intracellular Membranes / Q000378:metabolism; D009994:Osmolar Concentration; D012333:RNA, Messenger / Q000378:metabolism; D018048:Receptors, Purinergic P2 / Q000235:genetics / Q000502:physiology*; D013961:Thyroid Gland / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D013997:Time Factors; D014544:Uridine Triphosphate / Q000494:pharmacology
chemical_list: D015850:Interleukin-6; D012333:RNA, Messenger; D018048:Receptors, Purinergic P2; D000255:Adenosine Triphosphate; D002118:Calcium; D014544:Uridine Triphosphate