MIGRATION OF BOVINE BRONCHIAL EPITHELIAL-CELLS TO EXTRACELLULAR-MATRIX COMPONENTS

Migration of epithelial cells is an important feature of wound healing . Components of extracellular matrix stimulate migration of other cell s, and we hypothesized that basement membrane components, laminin and type IV collagen, stimulate migration of bovine bronchial epithelial c ells (BBEC). BBEC cultured for 3 days were used in migration assays us ing the blindwell chamber technique. BBEC migrated in a concentration- dependent manner to laminin, type IV collagen, and fibronectin, ''Chec kerboard'' analysis demonstrated that the migration was directional fo r each of the components studied. We also evaluated the stimulatory ac tivity of fibronectin fragments. A fragment containing the RGDS peptid e was stimulatory of migration while other fragments were much less so , suggesting a role for RGDS-sensitive, integrin-mediated mechanisms. In order to evaluate whether bound or soluble matrix components were r equired to direct cell migration, we performed haptotaxis assays with precoated filters in the migration chambers. Fibronectin-precoated fil ters demonstrated significant stimulation of migration, suggesting tha t some of the migration in our original assays with fibronectin presen t in the lower chambers could be termed haptotactic. Laminin- and type IV collagen-precoated filters were less active. When insulin was used as a chemoattractant, the fibronectin-precoated filters were more fac ilitatory of migration than the other matrix coatings. In summary, BBE C can, chemotactically migrate to extracellular matrix components. Thu s, the composition of the provisional matrix that forms at sites of ep ithelial injury may play an important role in the repair processes tha t occur after injury to the bronchial epithelium.