Degradation of heparan sulfate in the subendothelial extracellular matrix by a readily released heparanase from human neutrophils. Possible role in invasion through basement membranes.

Abstract

Freshly isolated human neutrophils were investigated for their ability to degrade heparan sulfate proteoglycans in the subendothelial extracellular matrix (ECM) produced by cultured corneal and vascular endothelial cells. The ECM was metabolically labeled with Na2(35S)04 and labeled degradation products were analyzed by gel filtration over Sepharose 6B. More than 90% of the released radioactivity consisted of heparan sulfate fragments 5-6 times smaller than intact heparan sulfate side chains released from the ECM by either papain or alkaline borohydride. These fragments were sensitive to deamination with nitrous acid and were not produced in the presence of either heparin or serine protease inhibitors. In contrast, degradation of soluble high molecular weight heparan sulfate proteoglycan, which was first released from the ECM, was inhibited by heparin but there was no effect of protease inhibitors. These results indicate that interaction of human neutrophils with the subendothelial ECM is associated with degradation of its heparan sulfate by means of a specific, newly identified, heparanase activity and that this degradation is facilitated to a large extent by serine proteases.The neutrophil heparanase was readily and preferentially released (15-25% of the cellular content in 60 min) by simply incubating the cells at 40C in the absence of added stimuli. Under these conditions, <5% of the cellular content of lactate dehydrogenase, lysozyme, and globin degrading proteases was released. Further purification of the neutrophil heparanase was achieved by its binding to heparin-Sepharose and elution at 1 M NaCI. It is suggested that heparanase activity is involved in the early events of extravasation and diapedesis of neutrophils in response to a threshold signal from an extravascular inflamed organ.

Heparanase-neutralizing antibodies attenuate lymphoma tumor growth and metastasis

“…4 and 5) is thus a result of neutralization of heparanase contributed by the tumor microenvironment. The microenvironment of B-cell lymphomas contains variable numbers of immune cells (i.e., T-cells, macrophages, neutrophils), stromal cells (i.e., fibroblasts), and endothelial cells (17,32,33), many of which have been reported to express heparanase (34,35). The significance of the tumor microenvironment in tumorigenesis is well documented and accepted (36).…”

Heparanase upregulation by colonic epithelium in inflammatory bowel disease

“…Among the few cell types that express heparanase under normal physiological conditions are placental cytothrophoblasts, skin keratinocytes and blood borne cells such as lymphocytes, neutrophils, macrophages and platelets. 2,3 Heparanase was localized to tertiary granules of neutrophils 6,27 and mast cells, 28 and its release by degranulation has been implicated in diapedesis of a number of immune cells, including neutrophils, macrophages, mast cells, dendritic cells and lymphocytes, 13,29,30 thus strongly implying heparanase as a pro-inflammatory mediator. Surprisingly, however, only a weak heparanase staining was observed in immune cells of IBD specimens ( Figure 2).…”

“…4,5 Traditionally, heparanase activity was well correlated with the metastatic potential of tumor-derived cells, attributed to enhanced cell dissemination as a consequence of HS cleavage and remodeling of the ECM barrier. [6][7][8][9] A proof-of-concept of this notion has recently been established by using a specific antiheparanase ribosyme and siRNA methodology, 10 clearly implicating heparanase activity as a critical requisite for metastatic spread. Similarly, heparanase was implicated in cell dissemination associated with inflammation and autoimmunity.…”

Spatial and temporal heparanase expression in colon mucosa throughout the adenoma-carcinoma sequence

“…1,2 Traditionally, heparanase activity was implicated in cellular invasion associated with angiogenesis, inflammation and cancer metastasis. [10][11][12][13][14] Recently, this notion gained further support by employing siRNA and ribozyme technologies, clearly depicting heparanase-mediated heparan sulfate cleavage and extracellular …”

“…1,2 Traditionally, heparanase activity was implicated in cellular invasion associated with angiogenesis, inflammation and cancer metastasis. [10][11][12][13][14] Recently, this notion gained further support by employing siRNA and ribozyme technologies, clearly depicting heparanase-mediated heparan sulfate cleavage and extracellular matrix remodeling as critical requisites for metastatic spread. 15 Since the cloning of the heparanase gene and the availability of specific molecular probes, heparanase upregulation was documented in an increasing number of primary human tumors.…”