Migrating keratinocytes express urokinase-type plasminogen activator.

When confluent keratinocyte cultures were wounded by cutting with a blade, the cells rapidly retracted from the wounded site, leaving an area denuded of cells. Within 3-4 h of wounding, keratinocytes began to migrate from the edges and gradually reepithelialized the entire denuded area. Mitomycin C did not prevent the reepithelialization but did dramatically inhibit [3H]thymidine incorporation into the leading edge of cells. These results indicate that cell proliferation was not required for reepithelialization. Using a rabbit antibody against urokinase-type plasminogen activator (u-PA) and an avidin-biotin-peroxidase detection method, we localized u-PA in the keratinocytes at the leading edge of the migrating cultures. Cytochalasin B dramatically inhibited the extent of migration and also altered cell morphology; nonetheless, urokinase was detected in the limited number of cells that moved into the wounded area, even in the presence of cytochalasin B. A small but consistent enhancement (36% +/- 9) of plasminogen activator activity was observed in the supernatant of wounded cultures. These data suggest that plasminogen activator may be involved in the migration of keratinocytes that occurs during wound healing.

Duke Scholars

Author Gerald Sylvan Lazarus Dermatology