Mast cell tryptase potentiates neutrophil extracellular trap formation

• Previous research has indicated an intimate functional communication between mast cells and neutrophils during inflammatory conditions, but the nature of such communication is not fully understood. Activated neutrophils are known to release DNA-containing extracellular traps (NETs) and, based on the known ability of tryptase to interact with negatively charged polymers, we here hypothesized that tryptase might interact with NET-contained DNA and thereby regulate NET formation. In support of this, we show that tryptase markedly enhances NET formation in phorbol myristate acetate (PMA)-activated human neutrophils. Moreover, tryptase was found to bind vividly to the NETs, to cause proteolysis of core histones and to cause a reduction in the levels of citrullinated histone-3. Secretome analysis revealed that tryptase caused increased release of numerous neutrophil granule compounds, including gelatinase, lactoferrin and myeloperoxidase. We also show that DNA can induce the tetrameric, active organization of tryptase, suggesting that NET-contained DNA can maintain tryptase activity in the extracellular milieu. In line with such a scenario, DNA-stabilized tryptase was shown to efficiently degrade numerous pro-inflammatory compounds. Finally, we show that tryptase is associated with NET formation in vivo in a melanoma setting, and that NET formation in vivo is attenuated in mice lacking tryptase expression. Altogether, these findings reveal that NET formation can be regulated by mast cell tryptase, thus introducing a novel mechanism of communication between mast cells and neutrophils.

Ämnesord

NATURVETENSKAP  -- Biologi -- Immunologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Immunology (hsv//eng)

Nyckelord

mast cells

neutrophils

tryptase

neutrophil extracellular traps

histones

melanoma

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)