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Activation and Measurement of NLRP3 Inflammasome Activity Using IL-1β in Human Monocyte-derived Dendritic Cells
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Mitochondrial cardiolipin is required for Nlrp3 inflammasome activation

Shankar S Iyer1, Qiong He1,2, John R Janczy1,2

  • 1Inflammation Program, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA.

Immunity
|August 20, 2013
PubMed

Insights

The Nlrp3 inflammasome can be activated independently of reactive oxygen species (ROS) by the antibiotic linezolid. This pathway converges on mitochondrial dysfunction and direct binding of cardiolipin to Nlrp3.

Area of Science:

  • Immunology
  • Molecular Biology
  • Cell Biology

Background:

  • Nlrp3 inflammasome activation is crucial in immune responses but its precise mechanism remains elusive.
  • Previously identified Nlrp3 agonists consistently induce mitochondrial reactive oxygen species (ROS), suggesting ROS as a necessary upstream mediator.
  • The role of mitochondrial dysfunction in Nlrp3 inflammasome activation requires further elucidation.

Purpose of the Study:

  • To investigate novel agonists and mechanisms of Nlrp3 inflammasome activation.
  • To determine if Nlrp3 activation can occur independently of ROS.
  • To identify the specific mitochondrial components involved in Nlrp3 inflammasome assembly.

Main Methods:

  • Screening of compounds for Nlrp3 inflammasome activation.
  • Assessment of ROS generation in response to Nlrp3 agonists.
  • Analysis of mitochondrial function and cardiolipin levels.
  • Direct binding assays between Nlrp3 and cardiolipin.
  • Genetic or chemical inhibition of cardiolipin synthesis.

Main Results:

  • The oxazolidinone antibiotic linezolid was identified as a Nlrp3 agonist.
  • Linezolid-induced Nlrp3 activation proceeded independently of ROS generation.
  • Both ROS-dependent and ROS-independent pathways converged on mitochondrial dysfunction.
  • Cardiolipin was found to bind directly to Nlrp3.
  • Inhibition of cardiolipin synthesis abrogated Nlrp3 inflammasome activation.

Conclusions:

  • Mitochondria play a critical role in Nlrp3 inflammasome activation.
  • Nlrp3 inflammasome activation can occur via ROS-dependent and ROS-independent pathways.
  • Mitochondrial cardiolipin directly interacts with Nlrp3, mediating inflammasome activation.

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