The av integrins are likely to be an important group of molecules for regulating astrocyte behaviour within the central nervous system. Together with their ligand vitronectin, they are expressed by astrocytes in vivo and are further upregulated during neurological disease. Here we have characterised the expression of αv integrins on primary astrocytes from both rat and mouse, and shown that they express just two members, αvβ5 and αvβ8. By using RGD peptides and function-blocking antibodies against the β1 integrins and αvβ5, we find that both αvβ5 and αvβ8 can act as functional receptors for vitronectin, However, while αvβ5 is largely responsible for astrocyte adhesion to vitronectin this integrin appears to play no role in migration on vitronectin, with αvβ8 playing the dominant role in promoting migration on this substrate. pi integrins are not involved in mediating interactions between astrocytes and vitronectin, These results were confirmed in experiments with astrocytes derived from mice in which the β5 gene had been deleted by homologous recombination. β5 null astrocytes attached to vitronectin at a reduced rate, but showed no defect in migration on vitronectin relative to wild-type astrocytes. These data provide the first evidence that αvβ8 regulates migration and show that astrocyte αvβ5 and αvβ8 integrins have distinct functions.
|Number of pages||9|
|Journal||Journal of Cell Science|
|Publication status||Published - 1999|