Explant cultures of embryonic rat dorsal root ganglia exhibit heparanase expression in migrating cells

Abstract

Mammalian heparanase is an endo- -D-glucuronidase that cleaves heparan sulfate moieties of proteoglycans at limited sites. Its enzymatic activity is strongly implicated in the regulation of cell growth, migration and differentiation of tumor cells, endothelial cells and inflammatory cells [1] . The findings of the differences in cellular expression of heparanase in normal adult spinal cord [2]open a new area for us to explore the functions of heparanase in cell migration, during neural development and regulation of cellular environments in adult neural tissue. Here, we provide in vitro evidence that heparanase expression correlates with cell migration as revealed by model cultures of embryonic rat dorsal root ganglia (DRG). Cells migrating away and cells about to exit the DRG core showed strong expression of heparanase protein and mRNA, while those cells remaining sessile in the DRG center showed low ISH signals. The upregulated expression of heparanase protein and endoglucuronidase activity in explant cultures compared with neat explants suggest heparanase functions as an active enzyme to facilitate the cellular emigration from the dorsal root ganglia in vitro. Acknowledgement: This work is supported by CRCG, The University of Hong Kong, grants 10204997&10205634 to D.K.Y.S. References 1 Vlodavsky I, et al: Nat Med 1999; 5: 793–802. 2 Zhang Y, et al: J Comp Neurol 2005.