L-plastin enhances NLRP3 inflammasome assembly and bleomycin-induced lung fibrosis

Hemant Joshi, Alison Almgren-Bell, Edgar P. Anaya, Elizabeth M. Todd, Steven Van Dyken, Anushree Seth, Katherine M. McIntire, Srikanth Singamaneni, Fayyaz Sutterwala, Sharon C. Morley

Research output: Contribution to journalArticlepeer-review

Abstract

Macrophage adhesion and stretching have been shown to induce interleukin (IL)-1β production, but the mechanism of this mechanotransduction remains unclear. Here we specify the molecular link between mechanical tension on tissue-resident macrophages and activation of the NLRP3 inflammasome, which governs IL-1β production. NLRP3 activation enhances antimicrobial defense, but excessive NLRP3 activity causes inflammatory tissue damage in conditions such as pulmonary fibrosis and acute respiratory distress syndrome. We find that the actin-bundling protein L-plastin (LPL) significantly enhances NLRP3 assembly. Specifically, LPL enables apoptosis-associated speck-like protein containing a caspase activation and recruitment domain (ASC) oligomerization during NLRP3 assembly by stabilizing ASC interactions with the kinase Pyk2, a component of cell-surface adhesive structures called podosomes. Upon treatment with exogenous NLRP3 activators, lung-resident alveolar macrophages (AMs) lacking LPL exhibit reduced caspase-1 activity, IL-1β cleavage, and gasdermin-D processing. LPL−/− mice display resistance to bleomycin-induced lung injury and fibrosis. These findings identify the LPL-Pyk2-ASC pathway as a target for modulation in NLRP3-mediated inflammatory conditions.

Original languageEnglish
Article number110507
JournalCell Reports
Volume38
Issue number11
DOIs
StatePublished - Mar 15 2022

Keywords

  • NLRP3 inflammasome
  • acute lung injury
  • cytoskeleton
  • infection
  • inflammation
  • lung fibrosis
  • macrophages
  • mechanotransduction
  • respiratory diseases
  • signal-transduction

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