title: Extracellular ATP induces oscillations of intracellular Ca2+ and membrane potential and promotes transcription of IL-6 in macrophages.
abstract: The effects of low concentrations of extracellular ATP on cytosolic Ca(2+), membrane potential, and transcription of IL-6 were studied in monocyte-derived human macrophages. During inflammation or infection many cells secrete ATP. We show here that application of 10 microM ATP or 10 microM UTP induces oscillations in cytosolic Ca(2+) with a frequency of approximately 12 min(-1) and oscillations in membrane potential. RT-PCR analysis showed expression of P2Y(1), P2Y(2), P2Y(11), P2X(1), P2X(4), and P2X(7) receptors, large-conductance (KCNMA1 and KCNMB1-4), and intermediate-conductance (KCNN4) Ca(2+)-activated K(+) channels. The Ca(2+)oscillations were unchanged after removal of extracellular Ca(2+), indicating that they were mainly due to movements of Ca(2+) between intracellular compartments. Comparison of the effects of different nucleotides suggests that the Ca(2+) oscillations were elicited by activation of P2Y(2) receptors coupled to phospholipase C. Patch-clamp experiments showed that ATP induced a transient depolarization, probably mediated by activation of P2X(4) receptors, followed by membrane potential oscillations due to opening of Ca(2+)-activated K(+) channels. We also found that 10 microM ATP gamma S increased transcription of IL-6 approximately 40-fold within 2 h. This effect was abolished by blockade of P2Y receptors with 100 microM suramin. Our results suggest that ATP released from inflamed, damaged, or metabolically impaired cells represents a "danger signal" that plays a major role in activating the innate immune system.
authors.affiliation: Institute of Physiology, Marburg University, Deutschhausstrasse 2, 35037 Marburg, Germany.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Hanley
authors.forename: Boris
authors.initials: B
authors.lastname: Musset
authors.forename: Vijay
authors.initials: V
authors.lastname: Renigunta
authors.forename: Sven H
authors.initials: SH
authors.lastname: Limberg
authors.forename: Alexander H
authors.initials: AH
authors.lastname: Dalpke
authors.forename: Rainer
authors.initials: R
authors.lastname: Sus
authors.forename: Klaus M
authors.initials: KM
authors.lastname: Heeg
authors.forename: Regina
authors.initials: R
authors.lastname: Preisig-Müller
authors.forename: Jürgen
authors.initials: J
authors.lastname: Daut
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology*; D002118:Calcium / Q000502:physiology*; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D005786:Gene Expression Regulation / Q000187:drug effects / Q000276:immunology; D006801:Humans; D015850:Interleukin-6 / Q000235:genetics*; D051037:Large-Conductance Calcium-Activated Potassium Channel alpha Subunits; D008264:Macrophages / Q000187:drug effects / Q000276:immunology / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects*; D008969:Molecular Sequence Data; D009991:Oscillometry; D018408:Patch-Clamp Techniques; D018048:Receptors, Purinergic P2 / Q000187:drug effects / Q000502:physiology; D012964:Sodium / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects*
chemical_list: D015850:Interleukin-6; C494841:KCNMA1 protein, human; D051037:Large-Conductance Calcium-Activated Potassium Channel alpha Subunits; D018048:Receptors, Purinergic P2; D000255:Adenosine Triphosphate; D012964:Sodium; D002118:Calcium