Necroptosis directly induces the release of full-length biologically active IL-33 in vitro and in an inflammatory disease model

FEBS J. 2019 Feb;286(3):507-522. doi: 10.1111/febs.14738. Epub 2019 Jan 4.


Interleukin-33 (IL-33) is a pro-inflammatory cytokine that plays a significant role in inflammatory diseases by activating immune cells to induce type 2 immune responses upon its release. Although IL-33 is known to be released during tissue damage, its exact release mechanism is not yet fully understood. Previously, we have shown that cleaved IL-33 can be detected in the plasma and epithelium of Ripk1-/- neonates, which succumb to systemic inflammation driven by spontaneous receptor-interacting protein kinase-3 (RIPK3)-dependent necroptotic cell death, shortly after birth. Thus, we hypothesized that necroptosis, a RIPK3/mixed lineage kinase-like protein (MLKL)-dependent, caspase-independent cell death pathway controls IL-33 release. Here, we show that necroptosis directly induces the release of nuclear IL-33 in its full-length form. Unlike the necroptosis executioner protein, MLKL, which was released in its active phosphorylated form in extracellular vesicles, IL-33 was released directly into the supernatant. Importantly, full-length IL-33 released in response to necroptosis was found to be bioactive, as it was able to activate basophils and eosinophils. Finally, the human and murine necroptosis inhibitor, GW806742X, blocked necroptosis and IL-33 release in vitro and reduced eosinophilia in Aspergillus fumigatus extract-induced asthma in vivo, an allergic inflammation model that is highly dependent on IL-33. Collectively, these data establish for the first time, necroptosis as a direct mechanism for IL-33 release, a finding that may have major implications in type 2 immune responses.

Keywords: DAMP; MLKL; IL-33; cell death; necroptosis.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / drug effects
  • Apoptosis / genetics
  • Apoptosis / immunology*
  • Aspergillus fumigatus / chemistry
  • Aspergillus fumigatus / immunology
  • Asthma / chemically induced
  • Asthma / drug therapy
  • Asthma / genetics
  • Asthma / immunology*
  • Basophils / drug effects
  • Basophils / immunology
  • Basophils / pathology
  • Cell Line
  • Complex Mixtures / administration & dosage
  • Complex Mixtures / chemistry
  • Complex Mixtures / immunology
  • Disease Models, Animal
  • Eosinophils / drug effects
  • Eosinophils / immunology
  • Eosinophils / pathology
  • Female
  • Fibroblasts / drug effects
  • Fibroblasts / immunology
  • Fibroblasts / pathology
  • Gene Expression Regulation
  • Humans
  • Immunity, Innate / drug effects
  • Interleukin-33 / genetics
  • Interleukin-33 / immunology*
  • Keratinocytes / drug effects
  • Keratinocytes / immunology
  • Keratinocytes / pathology
  • Mice
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Necrosis / genetics
  • Necrosis / immunology*
  • Necrosis / pathology
  • Necrosis / prevention & control
  • Primary Cell Culture
  • Protein Kinase Inhibitors / pharmacology
  • Protein Kinases / genetics
  • Protein Kinases / immunology*
  • Receptor-Interacting Protein Serine-Threonine Kinases / genetics
  • Receptor-Interacting Protein Serine-Threonine Kinases / immunology
  • Signal Transduction


  • Complex Mixtures
  • Il33 protein, mouse
  • Interleukin-33
  • Protein Kinase Inhibitors
  • MLKL protein, mouse
  • Protein Kinases
  • Receptor-Interacting Protein Serine-Threonine Kinases
  • Ripk3 protein, mouse