Purification and Characterization of the Endoglycosidase Heparanase 1 from Human Plantar Stratum Corneum: a Key Enzyme in Epidermal Physiology?

Abstract

A protein exhibiting endoglycosidase activity was purified from plantar stratum corneum to apparent homogeneity in two sequential column chromatographic steps. Protein sequencing revealed its identity with the recently cloned human heparanase 1, an enzyme, the expression of which is reported to be related to the metastasic potential of tumor cells. By using a heparanase 1 specific antibody we were able to demonstrate that, in the plantar stratum corneum, heparanase 1 exists in two forms, the active 50 kDa protein and the inactive 63 kDa form, probably a proform of the enzyme. The antibody also decorated numerous degradation fragments. Reverse transcription polymerase chain reaction studies as well as immunohistochemical analysis using reconstructed and normal human epidermis demonstrated clearly a keratinocyte differentiation related expression of heparanase 1. Interestingly, the antibody also strongly decorated dendritic cells, which after double labeling could be identified to be a subpopulation of the epidermal Langerhans cells. Based on our findings and the known history of this enzyme, we advanced the hypothesis that heparanase 1 has multiple physiologic functions in the epidermis: (i) it plays an important role in epidermal differentiation, possibly by modulating the liberation of heparan sulfate bound (growth) factors; (ii) in the stratum corneum, the endoglycosidase activity of heparanase 1 might be indispensable and represent the first step in the desquamation process; and (iii) in Langerhans cells, its catalytic activity is required for the trans-tissue migration of these cells.

Translocation of Active Heparanase to Cell Surface Regulates Degradation of Extracellular Matrix Heparan Sulfate upon Transmigration of Mature Monocyte-Derived Dendritic Cells

“…Moreover, addition of a chemoattractant FMLP induced heparanase redistribution at the leading edge of migration, and neutralizing anti-heparanase Abs significantly inhibited transmigration of PMA-treated cells (15). These results support the idea that translocation of cytoplasmic heparanase to the cell surface is involved in the migratory activity of mDCs, and the presence of heparanase in Langerhans cells supports the relevance of these findings in vivo (31).…”

Processing and activation of latent heparanase occurs in lysosomes

“…The role that heparanase may play in these and other pathologies (Dempsey et al, 2000b) is only poorly understood. Moreover, heparanase expression is not restricted to pathological conditions and high levels of activity have long been found in placenta and more recently in the skin (Bernard et al, 2001) and other tissues (Dempsey et al, 2000a). Specific heparanase inhibitors are expected to provide pivotal tools for studying heparanase functions under normal and pathological conditions.…”

Targeted ablation of Arnt in mouse epidermis results in profound defects in desquamation and epidermal barrier function

“…Among these enzymes are the stratum corneum chymotryptic and tryptic enzymes (SCCE and SCTE), stratum corneum thiol protease (SCTP or cathepsin L-2), cathepsin E, and cathepsin D (reviewed by Rawlings and Matts, 2005). Endoglucosidases including heparanase 1 (Bernard et al, 2001) and other enzymes are also known to play a role in corneosome degradation. Corneodesmosin, one of the major corneosomal components secreted by lamellar bodies during desmosome-to-corneosome transformation (Rawlings et al, 1994), also undergoes desquamation-associated proteolytic degradation, which appears to be inhibited by calcium (Rawlings and Matts, 2005).…”