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Evidence that elastase is the TNF‐R75 shedding enzyme in resting human polymorphonuclear leukocytes
Author(s) -
Gasparini Chiara,
Menegazzi Renzo,
Patriarca Pierluigi,
Dri Pietro
Publication year - 2003
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(03)01046-9
Subject(s) - elastase , serine protease , neutrophil elastase , biology , metalloproteinase , tumor necrosis factor alpha , receptor , stimulation , microbiology and biotechnology , biochemistry , protease , enzyme , inflammation , endocrinology , immunology
We previously showed that a metalloprotease and a serine protease mediate shedding of the TNF‐R75 (75‐kDa tumor necrosis factor receptor) in neutrophils. Here we show that elastase is the TNF‐R75 solubilizing serine protease. Release of the TNF‐R75 by resting cells was almost totally inhibited by the serine protease inhibitor diisopropylfluorophosphate (DFP), by two synthetic, chemically unrelated, elastase‐specific inhibitors and by α1‐protease inhibitor. Release after TNF or FMLP ( N ‐formyl‐ L ‐methionyl‐ L ‐leucyl‐ L ‐phenylalanine) stimulation was blocked by DFP and a metalloprotease inhibitor used in combination. Supernatants from resting neutrophils contained a 28‐kDa fragment of the receptor, compatible with that generated by elastase, whose appearance was inhibited by DFP. Upon FMLP stimulation, the release of 28‐kDa and 40‐kDa fragments was observed, which was inhibited by DFP and a metalloprotease inhibitor, respectively. We conclude that elastase is the TNF‐R75 sheddase of resting neutrophils and that it contributes to shedding of this receptor in stimulated cells.