Heparanase activation induces epidermal hyperplasia, angiogenesis, lymphangiogenesis and wrinkles

To clarify the difference between cutaneous responses to single and repeated barrier disruption, changes of epidermal gene expression were examined by using RT-PCR. In repeatedly barrier-disrupted skin, heparanase was specifically up-regulated in epidermis. In addition, there was a marked decrease in heparan sulfate (HS) chains of perlecan in basement membrane at the dermal-epidermal junction (DEJ) compared with singly disrupted skin. HS chains form a reservoir for heparan sulfate-binding growth factors. In repeatedly barrier-disrupted skin, expression of vascular endothelial growth factor-A (VEGF-A), an angiogenic factor, was induced in epidermis, whereas thrombospondin-1 (TSP-1), an angiogenesis inhibitor, was down-regulated, and concomitantly blood vessels were elongated and enlarged in dermis. Expression of VEGF-C, a lymphangiogenesis factor, was augmented in epidermis of repeatedly barrier-disrupted skin, concomitantly with an increase in the number and size of lymphatic vessels. Topical application of a synthetic heparanase inhibitor, 1-[4-(1H-benzoimidazol-2-yl)phenyl]-3-[4-(1H-benzoimidazol-2-yl)phenyl]urea, to skin after barrier disruption significantly suppressed wrinkle formation, degradation of HS chains in the basement membrane, epidermal hyperplasia and the changes of blood and lymphatic vessels. These results suggest that chronic barrier disruption activates heparanase and induces gene expression changes, leading to increased growth factor interaction between epidermis and dermis, and facilitating various cutaneous changes, including wrinkle formation.