Developmental regulation of alpha v integrins produces functional changes in astrocyte behavior

To examine the role of the extracellular matrix in regulating astrocyte beh avior we previously characterized av integrin expression on postnatal astro cytes in vitro and found that they express alphav beta5 and alphav beta8. H ere we show that differentiation of immature cells into astrocytes is accom panied by developmental regulation of av integrins, downregulation of alpha v beta1 and alphav beta8, and upregulation of alphav beta5. In addition, us ing two previously described astrocyte cell lines, we found that the neurit e-permissive A7 cell line expressed high levels of alphav beta1 in addition to alphav beta5 and alphav beta8, while the neurite-inhibitory Neu7 cell l ine expressed only alphav beta5. To examine integrin function we generated clones of the Neu7 cell line expressing alphav beta1 or alphav beta3 in add ition to alphav beta5. This showed that the parent Neu7 cells migrated more slowly than the A7 cells on fibronectin and vitronectin, but that Neu7 cel ls expressing alphav beta1 or alphav beta3 integrins showed enhanced migrat ion on fibronectin and vitronectin, respectively. These results show that a v integrin expression is regulated during astrocyte development and confirm an instructive role in cell migration for alphav beta1 in embryonic cells and alphav beta3 in astroglial tumors.