Developmental regulation of αv integrins produces functional changes in astrocyte behavior

To examine the role of the extracellular matrix in regulating astrocyte behavior we previously characterized αv integrin expression on postnatal astrocytes in vitro and found that they express αvβ5 and αvβ8. Here we show that differentiation of immature cells into astrocytes is accompanied by developmental regulation of αv integrins, downregulation of αvβ1 and αvβ8, and upregulation of αvβ5. In addition, using two previously described astrocyte cell lines, we found that the neurite-permissive A7 cell line expressed high levels of αvβ1 in addition to αvβ5 and αvβ8, while the neurite-inhibitory Neu7 cell line expressed only αvβ5. To examine integrin function we generated clones of the Neu7 cell line expressing αvβ1 or αvβ3 in addition to αvβ5. This showed that the parent Neu7 cells migrated more slowly than the A7 cells on fibronectin and vitronectin, but that Neu7 cells expressing αvβ1 or αvβ3 integrins showed enhanced migration on fibronectin and vitronectin, respectively. These results show that αv integrin expression is regulated during astrocyte development and confirm an instructive role in cell migration for αvβ1 in embryonic cells and αvβ3 in astroglial tumors