title: Transient P2X7 receptor activation triggers macrophage death independent of Toll-like receptors 2 and 4, caspase-1, and pannexin-1 proteins.
abstract: The function of P2X(7) receptors (ATP-gated ion channels) in innate immune cells is unclear. In the setting of Toll-like receptor (TLR) stimulation, secondary activation of P2X(7) ion channels has been linked to pro-caspase-1 cleavage and cell death. Here we show that cell death is a surprisingly early triggered event. We show using live-cell imaging that transient (1-4 min) stimulation of mouse macrophages with high extracellular ATP ([ATP]e) triggers delayed (hours) cell death, indexed as DEVDase (caspase-3 and caspase-7) activity. Continuous or transient high [ATP]e did not induce cell death in P2X(7)-deficient (P2X(7)(-/-)) macrophages or neutrophils (in which P2X(7) could not be detected). Blocking sustained Ca(2+) influx, a signature of P2X(7) ligation, was highly protective, whereas no protection was conferred in macrophages lacking caspase-1 or TLR2 and TLR4. Furthermore, pannexin-1 (Panx1) deficiency had no effect on transient ATP-induced delayed cell death or ATP-induced Yo-Pro-1 uptake (an index of large pore pathway formation). Thus, "transient" P2X(7) receptor activation and Ca(2+) overload act as a death trigger for native mouse macrophages independent of Panx1 and pro-inflammatory caspase-1 and TLR signaling.
authors.affiliation: Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany,. Electronic address: hanley@uni-muenster.de.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Hanley
authors.affiliation: Institut für Physiologie II, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany.
authors.forename: Moritz
authors.initials: M
authors.lastname: Kronlage
authors.affiliation: Institut für Medizinische Mikrobiologie, Universität Duisburg-Essen, 45147 Essen, Germany.
authors.forename: Carsten
authors.initials: C
authors.lastname: Kirschning
authors.affiliation: Institut für Physiologie und Pathophysiologie, Philipps-Universität Marburg, 35037 Marburg, Germany.
authors.forename: Adriana
authors.initials: A
authors.lastname: Del Rey
authors.affiliation: Department of Experimental and Diagnostic Medicine, University of Ferrara, 44100 Ferrara, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Di Virgilio
authors.affiliation: Institute of Physiology and Biophysics, Aarhus University, DK-8000 Aarhus, Denmark.
authors.forename: Jens
authors.initials: J
authors.lastname: Leipziger
authors.affiliation: Neuroscience Centre of Excellence, MedImmune, Cambridge CB21 6GH, United Kingdom, and.
authors.forename: Iain P
authors.initials: IP
authors.lastname: Chessell
authors.affiliation: Institut für Physiologie II, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany.
authors.forename: Sarah
authors.initials: S
authors.lastname: Sargin
authors.affiliation: Klinische Neurobiologie, Neurologische Klinik, Universitätsklinikum Heidelberg, 69120 Heidelberg, Germany.
authors.forename: Mikhail A
authors.initials: MA
authors.lastname: Filippov
authors.affiliation: Institut für Physiologie II, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany.
authors.forename: Otto
authors.initials: O
authors.lastname: Lindemann
authors.affiliation: Institut für Physiologie II, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany.
authors.forename: Simon
authors.initials: S
authors.lastname: Mohr
authors.affiliation: Institut für Physiologie II, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany.
authors.forename: Volker
authors.initials: V
authors.lastname: Königs
authors.affiliation: Institut für Physiologie II, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany.
authors.forename: Hermann
authors.initials: H
authors.lastname: Schillers
authors.affiliation: Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Bähler
authors.affiliation: Institut für Physiologie II, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany.
authors.forename: Albrecht
authors.initials: A
authors.lastname: Schwab
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism; D020170:Caspase 1 / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D016923:Cell Death / Q000187:drug effects / Q000235:genetics; D002478:Cells, Cultured; D017630:Connexins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D017737:Macrophages, Peritoneal / Q000276:immunology / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D058486:Receptors, Purinergic P2X7 / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D051195:Toll-Like Receptor 2 / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D051197:Toll-Like Receptor 4 / Q000235:genetics / Q000276:immunology / Q000378:metabolism*
chemical_list: D017630:Connexins; D009419:Nerve Tissue Proteins; C503631:Panx1 protein, mouse; D058486:Receptors, Purinergic P2X7; C493486:Tlr2 protein, mouse; C493487:Tlr4 protein, mouse; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D000255:Adenosine Triphosphate; D020170:Caspase 1; D002118:Calcium