The insulin-like growth factor II/mannose 6-phosphate receptor is required for proliferin-induced angiogenesis

Proliferin stimulates endothelial cell migration in culture and neovascularization in vivo. Previous studies have demonstrated that proliferin can bind to the insulin-like growth factor II/mannose 6-phosphate receptor, and that binding can be blocked by mannose 6-phosphate. We have now found that this receptor plays an essential role in proliferin-induced angiogenesis. Proliferin binding to endothelial cells is blocked by the addition of mannose 6-phosphate, as is the ability of both recombinant and placental-derived proliferin to stimulate the migration of capillary endothelial cells in vitro and to induce neovascularization in the rat cornea. Consistent with a direct role of this receptor in angiogenesis, insulin-like growth factor II, as well as a mutant form of insulin-like growth factor II that binds to the insulin-like growth factor II/mannose 6- phosphate receptor but not to the insulin-like growth factor I receptor, also stimulate endothelial cell migration and neovascularization.