Role of cathepsin B in leech wound healing

The wound healing process in leeches involves different types of cells like macrophages, NK-like cells and granulocytes. These cells that are involved in immune defence, can co-operate to attack and/or isolate the non self (de Eguileor et al., 1999; de Eguileor et al., 2000a; de Eguileor et al., 2000b). In addition other types of cells, like fibroblasts and endothelial cells, are involved in the formation of new vessels. To exert their functional role, all these cells must infiltrate and migrate through extracellular matrix (de Eguileor et al., 2001a; de Eguileor et al., 2003). Here we show, by histochemical and biochemical methods, that the cathepsin B peptidase is present and active in all migrating cells, involved in immune responses of leeches subjected to different stimuli. Interstingly the cellular function of cathepsin B in invertebrates appear to be equivalent to that of vertebrates, where the secreted enzyme plays a role in basement membrane and matrix disruption operated by cells involved in angiogenesis, wound repair and immune defence.