The P2X7 receptor (P2X7R), an ATP-gated ion channel, has been implicated in the process of cell-to-cell fusion into multinucleated macrophages (MA), but its contribution to MA fusion driven by physiological/pathological stimuli is not clearly established. Based on several lines of evidence, we demonstrate that P2X7R is critical for the induction of multinucleated MA by the inflammatory cytokine GM-CSF: 1) pharmacological inhibition of P2X7R with oxidized ATP (oATP), KN-62, and the selective antagonist A740003 abrogated GM-CSF action on rat alveolar MA and murine peritoneal MA; 2) a murine J774 P2X7 low MA clone, selected for defective P2X7R function, was unresponsive; 3) MA from mice lacking P2X7R failed to respond to GM-CSF, in contrast to wild-type. GM-CSF also stimulated ATP-induced membrane permeabilization in J774 P2X7 high MA and rat alveolar MA, an effect absent in the P2X 7 low MA clone and inhibited by the P2X7 blockers oATP and KN-62. Notably, the stimulatory effects of GM-CSF on pore formation and MA fusion were both inhibited by blocking functional Pannexin-1 (Panx-1), and GM-CSF failed to stimulate MA fusion in cells from Panx-1 knockout mice. We provide further evidence that extracellular ATP release from peritoneal MA is dependent on P2X7 but not on Panx-1 expression and that its metabolism to adenosine mediates P2X7-dependent MA fusion. These data demonstrate that both P2X7 and Panx-1 are required for GM-CSF promotion of MA fusion but likely act independently through different signaling pathway(s). Copyright © 2011 by The American Association of Immunologists, Inc.

The P2X7 receptor and pannexin-1 are both required for the promotion of multinucleated macrophages by the inflammatory cytokine GM-CSF

FALZONI, Simonetta;PELLEGATTI, Patrizia;DI VIRGILIO, Francesco
2011

Abstract

The P2X7 receptor (P2X7R), an ATP-gated ion channel, has been implicated in the process of cell-to-cell fusion into multinucleated macrophages (MA), but its contribution to MA fusion driven by physiological/pathological stimuli is not clearly established. Based on several lines of evidence, we demonstrate that P2X7R is critical for the induction of multinucleated MA by the inflammatory cytokine GM-CSF: 1) pharmacological inhibition of P2X7R with oxidized ATP (oATP), KN-62, and the selective antagonist A740003 abrogated GM-CSF action on rat alveolar MA and murine peritoneal MA; 2) a murine J774 P2X7 low MA clone, selected for defective P2X7R function, was unresponsive; 3) MA from mice lacking P2X7R failed to respond to GM-CSF, in contrast to wild-type. GM-CSF also stimulated ATP-induced membrane permeabilization in J774 P2X7 high MA and rat alveolar MA, an effect absent in the P2X 7 low MA clone and inhibited by the P2X7 blockers oATP and KN-62. Notably, the stimulatory effects of GM-CSF on pore formation and MA fusion were both inhibited by blocking functional Pannexin-1 (Panx-1), and GM-CSF failed to stimulate MA fusion in cells from Panx-1 knockout mice. We provide further evidence that extracellular ATP release from peritoneal MA is dependent on P2X7 but not on Panx-1 expression and that its metabolism to adenosine mediates P2X7-dependent MA fusion. These data demonstrate that both P2X7 and Panx-1 are required for GM-CSF promotion of MA fusion but likely act independently through different signaling pathway(s). Copyright © 2011 by The American Association of Immunologists, Inc.
2011
Lemaire, I.; Falzoni, Simonetta; Zhang, B.; Pellegatti, Patrizia; DI VIRGILIO, Francesco
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11392/1506336
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