alphaVbeta8 integrin is a Schwann cell receptor for fibrin

The interaction of Schwann cells with molecules in the extracellular environment following peripheral nerve injury is a critical aspect of nerve repair. A principal component of this material is fibrin, which derives from fibrinogen infiltrating into the nerve after the injury. This study was undertaken to identify cell surface receptor(s) that mediate the interaction of Schwann cells with fibrin. We found that adhesion of Schwann cells to fibrin could be effectively inhibited by low concentrations of RGD-containing peptides. Among RGD-sensitive integrins expressed by Schwann cell, alphaVbeta8, but not alpha5beta1, was found to bind to fibrin-Sepharose. In contrast, both of these integrins bound to fibronectin-Sepharose. We also found that alphaV, but not alpha5 or beta1 integrin subunit, accumulated in focal contacts of Schwann cell plated on fibrin. Taken together, these results strongly suggest that alphaVbeta8 integrin is a Schwann cell receptor for fibrin.