Inhibition of Cranial Neural Crest Adhesion in Vitro and Migration in Vivo Using Integrin Antisense Oligonucleotides

Abstract

Although it is well-established that β_1 integrins play a functional role in the migration of cranial neural crest cells, little is known about the number or importance of their associated α subunits. Here, we have utilized antisense oligonucleotides (aONs) against various mammalian integrin α subunits to functionally “knock out” integrinsin vitro and in vivo. First, we examined the attachment in vitro of cranial neural crest cells to fibronectin and laminin in the presence of antisense or reversed-sense oligonucleotides using a quantitative adhesion assay. We found three α integrin aONs that blocked attachment to fibronectin substrates only, one that blocked attachment to laminin substrates only, and one that blocked attachment to both fibronectin and laminin. As expected, an aON to chick β_1 integrin reduced attachment to both fibronectin and laminin substrates. These results suggest that there are three or more functionally distinct integrin heterodimers on avian cranial neural crest cells. Second, we examined the ability of aONs against various α integrin subunits to perturb cranial neural crest migrationin vivoby injecting the oligonucleotides into the cranial mesenchyme through which neural crest cells migrate. Those α aONs that inhibited cell attachment in vitro also caused neural crest and/or neural tube abnormalities after injection in vivo.In addition, two aONs that had no effect in vitro did affect emigration of neural crest cells in vivo. Immunoprecipitations revealed that some integrin subunits were depleted after treatment with antisense but not reversed-sense oligonucleotides both in vivo and in vitro. The results suggest that integrin α subunits are required for cranial neural crest cell attachment and emigration.