Mast cell proteinases activate precursor forms of collagenase and stromelysin, but not of gelatinases A and B

Authors


Correspondence to D. E. Woolley, University Department of Medicine, University Hospital of South Manchester, West Didsbury, Manchester, England M20 8LR
Fax: +44 61 434 5194.

Abstract

Mast cell activation in vivo is often associated with areas of oedema and connective-tissue degradation. Tryptase and chymase are the major serine proteinases released by mast cells, but they appear to have little activity on most components of the extracellular matrix. The matrix metalloproteinases (MMP) are purported to degrade almost all connective tissue elements and are secreted by cells in the form of inactive precursors. Since the mechanisms of MMP activation in vivo are poorly understood we have examined the potential of mast cell proteinases to activate the precursor forms of human collagenase (MMP-1), stromelysin (MMP-3), gelatinase A (MMP-2) and gelatinase B (MMP-9).

Mast cell proteinases prepared from purified dog mastocytoma cells were shown to process and activate purified precursor forms of both MMP-1 and MMP-3. Using antipain and chymostatin, inhibitors for tryptase and chymase, respectively, it was demonstrated that both pMMP-1 and pMMP-3 were effectively processed and activated by the chymase component. By contrast, tryptase activated only pMMP-3. The mast cell proteinases were unable to process or activate purified precursor forms of MMP-2 and MMP-9. However, MMP-3 previously activated by mast cell proteinases was shown to activate pMMP-9, but not pMMP-2. Since we have no evidence that mast cells express these four metalloenzymes, the release of mast cell serine proteinases following activation/degranulation could contribute to local metalloproteinase activation and subsequent matrix degradation.

Abbreviations
MCP

mast cell products

pMMP-1

-2, -3 and -9, promatrix metalloproteinase 1, 2, 3 and 9

H2NPhHgAc

amino-phenylmercuric acetate

BzArgNH-Np

N-benzoyl-d,l-arginine p-nitroanilide

IL-1

interleukin-1

TNFα

tumour-necrosis factor α

TIMP

tissue inhibitor of metalloproteinases

Enzymes
 

Matrix metalloproteinases (EC 3.4.24.–)

 

vertebrate collagenase (EC 3.4.24.7)

 

stromelysin (EC 3.4.24.17)

 

gelatinase A (EC 3.4.24.24)

 

gelatinase B (EC 3.4.24.35)

 

serine proteinases (EC 3.4.21. –)

 

tryptase (EC 3.4.21.59)

 

chymase (EC 3.4.21.39)

Ancillary