title: Active Caspase-1 Induces Plasma Membrane Pores That Precede Pyroptotic Lysis and Are Blocked by Lanthanides.
abstract: Canonical inflammasome activation induces a caspase-1/gasdermin D (Gsdmd)-dependent lytic cell death called pyroptosis that promotes antimicrobial host defense but may contribute to sepsis. The nature of the caspase-1-dependent change in plasma membrane (PM) permeability during pyroptotic progression remains incompletely defined. We assayed propidium(2+) (Pro(2+)) influx kinetics during NLRP3 or Pyrin inflammasome activation in murine bone marrow-derived macrophages (BMDMs) as an indicator of this PM permeabilization. BMDMs were characterized by rapid Pro(2+) influx after initiation of NLRP3 or Pyrin inflammasomes by nigericin (NG) or Clostridium difficile toxin B (TcdB), respectively. No Pro(2+) uptake in response to NG or TcdB was observed in Casp1(-/-) or Asc(-/-) BMDMs. The cytoprotectant glycine profoundly suppressed NG and TcdB-induced lysis but not Pro(2+) influx. The absence of Gsdmd expression resulted in suppression of NG-stimulated Pro(2+) influx and pyroptotic lysis. Extracellular La(3+) and Gd(3+) rapidly and reversibly blocked the induced Pro(2+) influx and markedly delayed pyroptotic lysis without limiting upstream inflammasome assembly and caspase-1 activation. Thus, caspase-1-driven pyroptosis requires induction of initial prelytic pores in the PM that are dependent on Gsdmd expression. These PM pores also facilitated the efflux of cytosolic ATP and influx of extracellular Ca(2+) Although lanthanides and Gsdmd deletion both suppressed PM pore activity and pyroptotic lysis, robust IL-1β release was observed in lanthanide-treated BMDMs but not in Gsdmd-deficient cells. This suggests roles for Gsdmd in both passive IL-1β release secondary to pyroptotic lysis and in nonlytic/nonclassical IL-1β export.
authors.affiliation: Department of Pathology, Case Western Reserve University, Cleveland, OH 44106;
authors.forename: Hana M
authors.initials: HM
authors.lastname: Russo
authors.affiliation: Department of Pathology, Case Western Reserve University, Cleveland, OH 44106;
authors.forename: Joseph
authors.initials: J
authors.lastname: Rathkey
authors.affiliation: Department of Pharmacology, Case Western Reserve University, Cleveland, OH 44106; and.
authors.forename: Andrea
authors.identifier: 0000-0003-4209-2188
authors.initials: A
authors.lastname: Boyd-Tressler
authors.affiliation: Department of Pathology, Case Western Reserve University, Cleveland, OH 44106;
authors.forename: Michael A
authors.initials: MA
authors.lastname: Katsnelson
authors.affiliation: Department of Pathology, Case Western Reserve University, Cleveland, OH 44106;
authors.forename: Derek W
authors.identifier: 0000-0003-4387-8094
authors.initials: DW
authors.lastname: Abbott
authors.affiliation: Department of Pathology, Case Western Reserve University, Cleveland, OH 44106; Department of Pharmacology, Case Western Reserve University, Cleveland, OH 44106; and Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106 george.dubyak@case.edu.
authors.forename: George R
authors.identifier: 0000-0001-9720-4226
authors.initials: GR
authors.lastname: Dubyak
mesh_terms: D000818:Animals; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism*; D020170:Caspase 1 / Q000378:metabolism*; D002462:Cell Membrane / Q000473:pathology; D058847:Inflammasomes / Q000378:metabolism; D053583:Interleukin-1beta / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D028581:Lanthanoid Series Elements / Q000494:pharmacology; D008264:Macrophages / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D028044:Phosphate-Binding Proteins; D000069292:Pyroptosis / Q000502:physiology*; D000094524:Gasdermins
chemical_list: D051017:Apoptosis Regulatory Proteins; D020170:Caspase 1; D058847:Inflammasomes; D053583:Interleukin-1beta; D047908:Intracellular Signaling Peptides and Proteins; D028581:Lanthanoid Series Elements; D028044:Phosphate-Binding Proteins; C498368:Gsdmd protein, mouse; D000094524:Gasdermins