Neutrophil cannibalism triggers transforming growth factor β1 production and self regulation of neutrophil inflammatory function in monosodium urate monohydrate crystal-induced inflammation in mice

Arthritis Rheum. 2013 Mar;65(3):815-23. doi: 10.1002/art.37822.


Objective: To identify macrophage-independent sources of transforming growth factor β1 (TGFβ1) production during monosodium urate monohydrate (MSU) crystal-induced inflammation and to determine how TGFβ1 alters MSU crystal-recruited neutrophil functions.

Methods: C57BL/6J mice were injected intraperitoneally with MSU crystals with or without TGFβ1-neutralizing antibody. MSU crystal-recruited peritoneal and blood neutrophils were purified and cultured ex vivo. Peritoneal neutrophils were treated with the caspase inhibitor Q-VD-OPh, anti-TGFβ1 antibody, or fluorochrome-labeled apoptotic neutrophils. Neutrophils were analyzed for expression of annexin V, caspase 3, and TGFβ1 by flow cytometry or fluorescence microscopy, for superoxide production using the redox-sensitive dye water-soluble tetrazolium 1, and for TGFβ1 and interleukin-1β (IL-1β) production by enzyme-linked immunosorbent assay.

Results: Eighteen hours after MSU crystal administration in vivo, TGFβ1 levels were elevated in peritoneal lavage fluids, and a significant number of peritoneal neutrophils were TGFβ1+. Purified blood or peritoneal neutrophils cultured ex vivo showed TGFβ1+ neutrophils coexpressing the apoptosis marker caspase 3 and increased TGFβ1 production, both of which dropped following inhibition of apoptosis. Live neutrophils that had phagocytosed apoptotic neutrophils showed greatest TGFβ1 expression. Superoxide production by purified MSU crystal-recruited neutrophils ex vivo was enhanced by anti-TGFβ1 antibody treatment. Neutrophils purified from the peritoneum of MSU crystal-challenged mice treated with anti-TGFβ1 antibody produced elevated levels of superoxide, but neutrophil IL-1β production was unaffected.

Conclusion: Neutrophil cannibalism and TGFβ1 production have the potential to make a significant contribution to the controlled resolution of neutrophil-driven inflammatory diseases such as gout.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antioxidants / chemistry
  • Antioxidants / toxicity
  • Apoptosis / immunology
  • Cells, Cultured
  • Crystallization
  • Cytophagocytosis / immunology*
  • Disease Models, Animal
  • Gout / chemically induced
  • Gout / immunology*
  • Gout / pathology
  • Inflammation / chemically induced
  • Inflammation / immunology
  • Inflammation / pathology
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Neutrophils / cytology
  • Neutrophils / immunology*
  • Neutrophils / metabolism
  • Peritoneal Cavity / cytology
  • Respiratory Burst / immunology
  • Transforming Growth Factor beta1 / immunology
  • Transforming Growth Factor beta1 / metabolism*
  • Uric Acid / chemistry
  • Uric Acid / toxicity*


  • Antioxidants
  • Transforming Growth Factor beta1
  • Uric Acid