Reduction of streptolysin O (SLO) pore-forming activity enhances inflammasome activation

Peter A. Keyel, Robyn Roth, Wayne M. Yokoyama, John E. Heuser, Russell D. Salter

Research output: Contribution to journalArticle

22 Scopus citations

Abstract

Pore-forming toxins are utilized by bacterial and mammalian cells to exert pathogenic effects and induce cell lysis. In addition to rapid plasma membrane repair, macrophages respond to pore-forming toxins through activation of the NLRP3 inflammasome, leading to IL-1β secretion and pyroptosis. The structural determinants of pore-forming toxins required for NLRP3 activation remain unknown. Here, we demonstrate using streptolysin O (SLO) that pore-formation controls IL-1β secretion and direct toxicity. An SLO mutant incapable of pore-formation did not promote direct killing, pyroptosis or IL-1β production. This indicated that pore formation is necessary for inflammasome activation. However, a partially active mutant (SLO N402C) that was less toxic to macrophages than wild-type SLO, even at concentrations that directly lysed an equivalent number of red blood cells, enhanced IL-1β production but did not alter pyroptosis. This suggests that direct lysis may attenuate immune responses by preventing macrophages from successfully repairing their plasma membrane and elaborating more robust cytokine production. We suggest that mutagenesis of pore-forming toxins represents a strategy to enhance adjuvant activity.

Original languageEnglish
Pages (from-to)1105-1118
Number of pages14
JournalToxins
Volume5
Issue number6
DOIs
StatePublished - Jun 2013

Keywords

  • Caspase-1
  • Inflammasome
  • NLRP3
  • Plasma membrane repair
  • Streptolysin O

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