Pannexin-1 is required for ATP release during apoptosis but not for inflammasome activation

J Immunol. 2011 Jun 1;186(11):6553-61. doi: 10.4049/jimmunol.1100478. Epub 2011 Apr 20.

Abstract

Apoptotic cell death is important for embryonic development, immune cell homeostasis, and pathogen elimination. Innate immune cells also undergo a very rapid form of cell death termed pyroptosis after activating the protease caspase-1. The hemichannel pannexin-1 has been implicated in both processes. In this study, we describe the characterization of pannexin-1-deficient mice. LPS-primed bone marrow-derived macrophages lacking pannexin-1 activated caspase-1 and secreted its substrates IL-1β and IL-18 normally after stimulation with ATP, nigericin, alum, silica, flagellin, or cytoplasmic DNA, indicating that pannexin-1 is dispensable for assembly of caspase-1-activating inflammasome complexes. Instead, thymocytes lacking pannexin-1, but not the P2X7R purinergic receptor, were defective in their uptake of the nucleic acid dye YO-PRO-1 during early apoptosis. Cell death was not delayed but, unlike their wild-type counterparts, Panx1(-/-) thymocytes failed to recruit wild-type peritoneal macrophages in a Transwell migration assay. These data are consistent with pannexin-1 liberating ATP and other yet to be defined "find me" signals necessary for macrophage recruitment to apoptotic cells.

MeSH terms

  • Adenosine Triphosphate / metabolism*
  • Adenosine Triphosphate / pharmacology
  • Animals
  • Apoptosis Regulatory Proteins / metabolism
  • Apoptosis*
  • Benzoxazoles / metabolism
  • Benzoxazoles / pharmacokinetics
  • Blotting, Western
  • Calcium-Binding Proteins / metabolism
  • Carrier Proteins / metabolism
  • Caspase 1 / metabolism
  • Cell Movement
  • Cell Survival
  • Cells, Cultured
  • Connexins / genetics
  • Connexins / metabolism*
  • DNA-Binding Proteins
  • Flow Cytometry
  • Inflammasomes / metabolism*
  • Interleukin-18 / metabolism
  • Interleukin-1beta / metabolism
  • Macrophages / cytology
  • Macrophages / metabolism
  • Macrophages, Peritoneal / cytology
  • Macrophages, Peritoneal / metabolism
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • NLR Family, Pyrin Domain-Containing 3 Protein
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / metabolism*
  • Nuclear Proteins / metabolism
  • Quinolinium Compounds / metabolism
  • Quinolinium Compounds / pharmacokinetics
  • Receptors, Purinergic P2X7 / genetics
  • Receptors, Purinergic P2X7 / metabolism
  • Thymus Gland / cytology
  • Thymus Gland / metabolism

Substances

  • Aim2 protein, mouse
  • Apoptosis Regulatory Proteins
  • Benzoxazoles
  • Calcium-Binding Proteins
  • Carrier Proteins
  • Connexins
  • DNA-Binding Proteins
  • Inflammasomes
  • Interleukin-18
  • Interleukin-1beta
  • Ipaf protein, mouse
  • NLR Family, Pyrin Domain-Containing 3 Protein
  • Nerve Tissue Proteins
  • Nlrp3 protein, mouse
  • Nuclear Proteins
  • Panx1 protein, mouse
  • Quinolinium Compounds
  • Receptors, Purinergic P2X7
  • YO-PRO 1
  • Adenosine Triphosphate
  • Caspase 1