Heparanase-mediated cleavage of macromolecular heparin accelerates release of granular components of mast cells from extracellular matrices

Heparanase cleaves macromolecular heparin in the secretory granules of connective tissue-type mast cells. We investigated roles of the cleavage under a microenvironment mimicking where the mast cells physiologically reside. A connective tissue-type mast cell line MST and mouse peritoneal cell-derived mast cells stored macromolecular heparin in the secretory granules. The cells expressing heparanase stored fragmented heparin (≈10 kDa) due to heparanase-dependent cleavage of the heparin. We produced an artificial collagen-based extracellular matrix and placed the live cells or glycosaminoglycans purified from the cells in the matrix to measure the release of sulfated macromolecules into the medium. The sulfate-radiolabeled molecules from the degranulating heparanase-expressing cells, and the purified glycosaminoglycans showed significantly greater release into the medium than those derived from mock cells, which was not the case in suspension culture. Mast cell granular enzyme chymase, but not beta-hexosaminidase, showed significantly greater release from the degranulating heparanase-expressing cells than from mock cells. Purified chymase mixed with fragmented heparin derived from heparanase-expressing cells showed greater release from collagen gels than the enzyme alone or mixed with maclomolecular heparin derived from mock cells. We propose that the cleavage of macromolecular heparin by heparanase accelerates the release of heparin and chymase from extracellular matric...

Source: BJ Cell - December 18, 2013 Category: Biochemistry Authors: N Higashi, M Waki, M Sue, Y Kogane, H Shida, N Tsunekawa, A Hasan, T Sato, A Kitahara, T Kasaoka, Y Hayakawa, M Nakajima, T Irimura Tags: BJ Biomolecules Source Type: research