Altered cytokine production in mice lacking P2X(7) receptors.
The P2X(7) receptor (P2X(7)R) is an ATP-gated ion channel expressed by monocytes and macrophages. To directly address the role of this receptor in interleukin (IL)-1 beta post-translational processing, we have generated a P2X(7)R-deficient mouse line. P2X(7)R(-/-) macrophages respond to lipopolysaccharide and produce levels of cyclooxygenase-2 and pro-IL-1 beta comparable with those generated by wild-type cells. In response to ATP, however, pro-IL-1 beta produced by the P2X(7)R(-/-) cells is not externalized or activated by caspase-1. Nigericin, an alternate secretion stimulus, promotes release of 17-kDa IL-1 beta from P2X(7)R(-/-) macrophages. In response to in vivo lipopolysaccharide injection, both wild-type and P2X(7)R(-/-) animals display increases in peritoneal lavage IL-6 levels but no detectable IL-1. Subsequent ATP injection to wild-type animals promotes an increase in IL-1, which in turn leads to additional IL-6 production; similar increases did not occur in ATP-treated, LPS-primed P2X(7)R(-/-) animals. Absence of the P2X(7)R thus leads to an inability of peritoneal macrophages to release IL-1 in response to ATP. As a result of the IL-1 deficiency, in vivo cytokine signaling cascades are impaired in P2X(7)R-deficient animals. Together these results demonstrate that P2X(7)R activation can provide a signal that leads to maturation and release of IL-1 beta and initiation of a cytokine cascade.
Solle
M
M
Department of Respiratory, Allergy, Immunology, Inflammation, and Infectious Diseases, Pfizer Inc., Groton, Connecticut 06340, USA.
Labasi
J
J
Perregaux
D G
DG
Stam
E
E
Petrushova
N
N
Koller
B H
BH
Griffiths
R J
RJ
Gabel
C A
CA
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002478:Cells, Cultured; D051546:Cyclooxygenase 2; D004790:Enzyme Induction / Q000187:drug effects; D005456:Fluorescent Dyes / Q000378:metabolism; D017353:Gene Deletion; D018390:Gene Targeting; D007249:Inflammation / Q000235:genetics; D007375:Interleukin-1 / Q000096:biosynthesis* / Q000378:metabolism; D015850:Interleukin-6 / Q000096:biosynthesis / Q000378:metabolism; D007527:Isoenzymes / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D009550:Nigericin / Q000494:pharmacology; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism; D011498:Protein Precursors / Q000096:biosynthesis* / Q000378:metabolism; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D058910:Purinergic P2 Receptor Agonists; D018048:Receptors, Purinergic P2 / Q000172:deficiency* / Q000235:genetics / Q000502:physiology*; D058486:Receptors, Purinergic P2X7
D005456:Fluorescent Dyes; D007375:Interleukin-1; D015850:Interleukin-6; D007527:Isoenzymes; D008070:Lipopolysaccharides; C546469:P2rx7 protein, mouse; D011498:Protein Precursors; D058910:Purinergic P2 Receptor Agonists; D018048:Receptors, Purinergic P2; D058486:Receptors, Purinergic P2X7; C043830:interleukin 1 precursor; D000255:Adenosine Triphosphate; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases; D009550:Nigericin